Note: Descriptions are shown in the official language in which they were submitted.
MAGNETIC BEARINGS AND ELECTRIC MOTORS
CROSS REFERENCE TO RELATED APPLICATIONS
[001] This application claims priority to International Patent Application No.
PCT/US2021/042859, filed on July 22, 2021. This application further claims
priority to U.S.
Continuation Patent Application No. 17/497,033 filed on October 8, 2021, U.S
Continuation
Patent Application No. 17/501,424 filed October 14, 2021, and U.S.
Continuation Patent
Application No. 17/534,390 filed November 23, 2021.
FIELD OF THE DISCLOSURE
[002] The present disclosure relates broadly to magnetic bearings and electric
motors, which
have inter alia a novel configuration of permanent magnets. In particular,
this disclosure
relates to a new type of magnetic bearing which uses piezoelectric elements to
push permanent
magnets or electromagnets together or pull them apart, allowing the magnetic
bearing to
withstand high amounts of torque with high efficiency. Novel configurations of
permanent
magnets allow the magnetic bearing to remain stable at load and over long
operating times. In
addition, this disclosure relates to a new type of electric stepper motor
which uses piezoelectric
elements to push permanent magnets or electromagnets together or pull them
apart to create
rotational force, delivering high amounts of torque with high efficiency and
high precision.
Novel configurations of permanent magnets allow the motor assembly to deliver
large amounts
of torque while providing high precision while remaining stable at load and
over long operating
times. Yet further, this disclosure relates to a new type of electronic motor
with a position
sensor which uses piezoelectric elements to detect the interaction of
permanent magnets or
electromagnets. The sensor is integrated into a brushless electric motor
design. Novel
configurations of permanent magnets allow the motor assembly to deliver large
amounts of
torque while remaining stable at load and over long operating times but still
delivering
extremely precise and reliable sensor position information.
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BACKGROUND
[003] One aspect of the present disclosure relates to a magnetic bearing.
Magnetic bearings
are well-known in the art: the fact that similar poles of a magnet repel each
other has been used
for everything up to and including levitating entire high-speed trains. The
advantages of
magnetic bearings are that they can be switched on and off, or varied in power
as required by
the load, and that they are entirely contact-free, which means that there is
no physical friction
between the bearing and the load as there would be when using a roller
bearing, ball bearing,
or other type conventional physical bearing.
[004] While magnetic bearings were a large improvement over physical bearings
in many
ways, as they have less frictional load, they have many inefficiencies. Most
magnetic bearings
use electromagnets. Constantly power cycling and/or reversing the
electromagnets causes
electrical inefficiencies, and the windings of the electromagnets can suffer
fatigue and/or heat
breakdown which causes the bearing to become inefficient or stop functioning.
[005] Electromagnets are also fairly heavy and contribute to parasitic load
and/or weight
inefficiency.
[006] A magnetic bearing which did not use electromagnets and therefore was
more efficient
and more economical to build would be a useful invention. A magnetic bearing
which did not
use electromagnets and was therefore more efficient and economical to power
would be a
useful invention. A magnetic bearing which did not use electromagnets and was
therefore more
durable and reliable would be a useful invention. This aspect of the present
disclosure, relating
to a magnetic bearing, may at least partially address these concerns.
[007] Another aspect of the present disclosure relates to electric stepper
motors. Electric
stepper motors are well-known in the art: electric stepper motors date from
the first half of the
20th Century.
[008] Stepper motors are electric motors which use gears or other physical
positional
detection means to switch the motor on and off when it moves through a fixed
fraction of its
full rotation. Traditionally, the gear uses a switching system of some kind
and turns the motor
off after it moves through a fixed fraction of its rotation. In such motors it
is necessary to turn
the motor on, let it advance one fixed fraction, and then turn it on again,
repeating until it
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reaches the desired number of full or fractional rotations.
[009] For instance, if the fixed fraction is one-one-hundredth of a full
rotation, and it is desired
to rotate the motor through half a rotation, the motor must go through fifty
"steps" of activation,
movement, and deactivation. If it is desired to rotate the motor through two
and a half rotations,
the motor must go through two hundred and fifty steps. As is obvious, the more
steps that are
used, the more possibility for error or uncertainty enters into a given set of
rotations. Also,
gears wear, producing additional uncertainty and eventual failure in the
precise rotation of the
stepper motor.
[0010] Like most modern motors, most stepper motors use electromagnets to turn
electrical
energy into rotational energy. Electromagnets are expensive, heavy, and prone
to multiple
kinds of failure. They are also very energy- inefficient and uneconomical to
operate.
[0011] An electric stepper motor which did not use gears or equivalent
physical on/off controls
and was therefore more durable and reliable would be a useful invention. An
electric stepper
motor which did not use electromagnets and therefore was more efficient and
more economical
to build would be a useful invention. An electric stepper motor which did not
use
electromagnets and was therefore more efficient and economical to power would
be a useful
invention. An electric stepper motor which did not use electromagnets andwas
therefore more
durable and reliable would be a useful invention. An electric stepper motor
which did not use
electromagnets and was therefore lighter than a motor of equivalent output
which did use
electromagnets would be a useful invention. This aspect of the present
disclosure, relating to
electric stepper motors, may at least partially address these concerns.
[0012] Another aspect of the present disclosure relates to a brushless
electric motor with
integrated positional sensing. Electric motors and positional sensing are well-
known in the art:
the "brushless" type of electric motor dates from the latter half of the 20th
Century and uses
solid-state electronics to replace the physical commutator (polarity reversal
switch) that
allowed brush-type electric motors to function. Positional sensing, dating
back to switches that
tripped when an element of a larger machine physically engaged them, is
likewise well-known
in the art.
[0013] While brushless motors were a large improvement in many ways, as they
have less
frictional load and fewer mechanical parts, they have many inefficiencies.
Constantly reversing
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the electromagnets causes electrical inefficiencies, and the windings of the
electromagnets can
suffer fatigue and/or heat breakdown which causes the motor to become
inefficient or stop
functioning. While brushless motors are typically more than 50% efficient in
terms of
mechanical energy out compared to electrical energy in, they do suffer from
loss of energy due
to various factors such as wire heating, resistance, et cetera. Brushless
motors require
intricately wound electromagnetic rotor and/or stator magnets which are
expensive and
inefficient to construct.
[0014] Electromagnets are also fairly heavy and contribute to parasitic load
and/or weight
inefficiency. Historically, positional sensing was done by some external
detection means, such
.. as a switch or counter. This adds complexity and expense. Traditional
electric motors can also
be used to detect countermotion by a load or torque: if something moves the
rotor of an electric
motor, it will induce a current in the motor. (As is well known to persons of
ordinary skill in
the art, if you turn a motor, you create a generator.) The current can be
detected and used to
indicate that the motor is being turned. However, traditional motors do not
provide fine enough
.. creation and detection of such currents to precisely identify the position
of the motor's rotor or
elements affixed to the rotor of the motor. In many applications, such as
robotics, it would be
extremely useful to be able to precisely detect the position/motion of the
rotor of a motor or
the elements affixed to the rotor of the motor.
[0015] An electric motor with positional sensing which did not use
electromagnets and
therefore was more efficient and more economical to build would be a useful
invention. An
electric motor with positional sensing which did not use electromagnets and
was therefore more
efficient and economical to power would be a useful invention. An electric
motor with
positional sensing which did not use electromagnets and was therefore more
durable and
reliable would be a useful invention. An electric motor with positional
sensing which did not
.. use electromagnets and was therefore lighter than a motor of equivalent
output which did use
electromagnets would be a useful invention. An electric motor with positional
sensing which
did not require external detection means and produced a precise measurement of
the position
and/or motion of the motor would be a useful invention. This aspect of the
present disclosure,
relating to a brushless electric motor with integrated positional sensing, may
at least partially
address these concerns.
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[0016] This background information is provided to reveal information believed
by the
applicant to be of possible relevance. No admission is necessarily intended,
nor should be
construed, that any of the preceding information constitutes prior art or
forms part of the
general common knowledge in the relevant art.
SUMMARY
[0017] The following presents a simplified summary of the general inventive
concept(s)
described herein to provide a basic understanding of some aspects of the
disclosure. This
summary is not an extensive overview of the disclosure. It is not intended to
restrict key or
critical elements of embodiments of the disclosure or to delineate their scope
beyond that which
is explicitly or implicitly described by the following description and claims.
[0018] Generally, among the many objectives of the present disclosure is the
provision of a
magnetic bearing. One objective is the provision of a magnetic bearing which
uses piezoelectric
impulse and permanent magnets as a source of generating mechanical energy from
electrical
energy and using that mechanical energy to support and control the magnetic
bearing. Another
objective is the provision of a magnetic bearing which does not use
electromagnets and is
therefore more efficient and economical to construct. Another objective is the
provision of a
magnetic bearing which does not use electromagnets and is therefore more
efficient and
economical to operate. Yet another objective is the provision of a magnetic
bearing which does
not use electromagnets and is therefore more durable and easier to maintain.
Other advantages
and objectives of the magnetic bearing disclosed will become clear by reading
the application
and the disclosures herein.
[0019] In accordance with one aspect of the present disclosure, there is
provided a magnetic
bearing comprising: a) at least one group of piezoelectric actuators, the at
least one group of
piezoelectric actuators comprising at least one piezoelectric actuator, all of
the piezoelectric
actuators electrically connected to a power supply; b) a group of actuator
magnets, the group
of actuator magnets comprising at least one actuator magnet, each of the at
least one
piezoelectric actuators mechanically affixed to the group of actuator magnets;
c) a group of
response magnets, the group of response magnets physically opposed to the
first plurality of
piezoelectric elements separated by a variable gap having a size, such that
when one or more
of the plurality of piezoelectric actuators are energized by the power supply,
the size of the
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variable gap changes; and d) a bearing assembly including a mobile assembly
and a static
assembly, the mobile assembly mechanically affixed to either the group of
actuator magnets or
the group of response magnets, the static assembly mechanically affixed to
whichever of the
group of actuator magnets or the group of response magnets the mobile assembly
is not
mechanically affixed, such that a magnetic repulsion force between the
actuator magnets and
the response magnets acts to maintain the size of the variable gap against a
load.
[0020] In one embodiment, there is one and only one group of piezoelectric
actuators, and the
one and only one group of piezoelectric actuators comprises one and only one
piezoelectric
actuator, and there is one and only one group of actuator magnets, and the one
and only one
group of actuator magnets comprises two actuator magnets.
[0021] In one embodiment, the group of response magnets comprises a single
piece of
magnetic material, the single piece of magnetic material having a plurality of
magnetic regions,
each magnetic region having a local north pole and a local south pole.
[0022] In one embodiment, the magnetic bearing further comprises e) a group of
actuator
capacitor plates, the group of actuator capacitor plates comprising at least
one actuator
capacitor plate, the group of actuator capacitor plates connected to the power
supply and
mechanically affixed to a housing of the magnetic bearing such that when the
group of
capacitor plates are energized by the power supply, they form a capacitor
circuit with one or
more of the piezoelectric actuators, causing a current to be induced in the
piezoelectric
actuators in the capacitor circuit.
[0023] In one embodiment, there are two groups of piezoelectric actuators,
further comprising:
e) a first group of piezoelectric actuators forming a group of stator
piezoelectric actuators, each
of the stator piezoelectric actuators mechanically affixed to a stator magnet;
and f) a second
group of piezoelectric actuators forming a group of rotor piezoelectric
actuators, each of the
.. rotor piezoelectric actuators mechanically affixed to a rotor magnet.
[0024] In one embodiment, the magnetic bearing further comprises g) a group of
actuator
capacitor plates, the group of actuator capacitor plates comprising at least
one actuator
capacitor plate, the group of actuator capacitor plates connected to the power
supply and
mechanically affixed to a housing of the magnetic bearing such that when the
group of
capacitor plates are energized by the power supply, they form a capacitor
circuit with one or
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more of the piezoelectric actuators, causing a current to be induced in the
piezoelectric
actuators in the capacitor circuit.
[0025] In one embodiment, each group of actuator magnets has two ends, and the
actuator
magnets in each group of actuator magnets overlap each other to produce a
combined actuator
magnetic field, and each of the actuator magnets in a group of actuator
magnets has a north
pole and a south pole, and the south pole of any particular actuator magnet is
either physically
proximate to one of the two ends, or to the north pole of another actuator
magnet in the group
of actuator magnets, and the north pole of any particular actuator magnet is
either physically
proximate to one of the two ends, or to the south pole of another actuator
magnet in the group
of actuator magnets.
[0026] In one embodiment, each group of actuator magnets has two ends, and the
actuator
magnets in each group of actuator magnets overlap each other to produce a
combined actuator
magnetic field, and each of the actuator magnets in a group of actuator
magnets has a north
pole and a south pole, and the south pole of any particular actuator magnet is
either physically
proximate to one of the two ends, or to the north pole of another actuator
magnet in the group
of actuator magnets, and the north pole of any particular actuator magnet is
either physically
proximate to one of the two ends, or to the south pole of another actuator
magnet in the group
of actuator magnets.
[0027] In one embodiment, the magnetic bearing further comprises e) a group of
elastic
members, the elastic members mechanically affixed to at least one
piezoelectric actuator such
that when the piezoelectric actuator is energized, the elastic member will
acquire an elastic
potential energy, and when the piezoelectric actuator is de-energized, the
elastic potential
energy will be converted into an elastic force which will push against the
piezoelectric actuator.
[0028] In one embodiment, the magnetic bearing further comprises e) a group of
elastic
members, the elastic members mechanically affixed to at least one
piezoelectric actuator such
that when the piezoelectric actuator is energized, the elastic member will
acquire an elastic
potential energy, and when the piezoelectric actuator is de-energized, the
elastic potential
energy will be converted into an elastic force which will push against the
piezoelectric actuator.
[0029] In one embodiment, the magnetic bearing further comprises f) a group of
elastic
members, the elastic members mechanically affixed to at least one
piezoelectric actuator such
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that when the piezoelectric actuator is energized, the elastic member will
acquire an elastic
potential energy, and when the piezoelectric actuator is de-energized, the
elastic potential
energy will be converted into an elastic force which will push against the
piezoelectric actuator.
[0030] In one embodiment, the magnetic bearing further comprises e) a group of
elastic
.. members, the elastic members mechanically affixed to at least one
piezoelectric actuator such
that when the piezoelectric actuator is energized, the elastic member will
acquire an elastic
potential energy, and when the piezoelectric actuator is de-energized, the
elastic potential
energy will be converted into an elastic force which will push against the
piezoelectric actuator.
[0031] In accordance with another aspect of the present disclosure, there is
provided a
magnetic bearing comprising: a) at least one group of static piezoelectric
actuators, the at least
one group of static piezoelectric actuators comprising at least one static
piezoelectric actuator,
all of the static piezoelectric actuators electrically connected to a power
supply; b) a group of
static magnets, the group of static magnets comprising at least one static
magnet, each of the
at least one static piezoelectric actuators mechanically affixed to the group
of static magnets;
c) at least one group of mobile piezoelectric actuators, the at least one
group of mobile
piezoelectric actuators comprising at least one mobile piezoelectric actuator,
all of the mobile
piezoelectric actuators electrically connected to the power supply; d) a group
of mobile
magnets, the group of mobile magnets comprising at least one mobile magnet,
each of the at
least one mobile piezoelectric actuators mechanically affixed to the group of
mobile magnets;
e) a motor assembly having a mobile assembly and a static assembly, the mobile
assembly
mechanically affixed to the group of mobile piezoelectric actuators, the
static assembly
mechanically affixed to the group of static piezoelectric actuators, such that
there is a variable
gap having a size between the group of mobile magnets and the group of static
magnets and
when the size of the variable gap changes, a magnetic force is exerted on the
mobile assembly,
causing the mobile assembly to move relative to the static assembly.
[0032] In one embodiment, the magnetic bearing further comprises f) a group of
energizer
capacitor plates, the group of energizer capacitor plates comprising at least
one energizer
capacitor plate, the group of actuator capacitor plates connected to the power
supply and
mechanically affixed to a housing of the magnetic bearing such that when the
group of
.. capacitor plates are energized by the power supply, they form a capacitor
circuit with one or
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more of the piezoelectric actuators, causing a current to be induced in the
piezoelectric
actuators in the capacitor circuit.
[0033] In one embodiment, each group of static magnets and/or each group of
mobile magnets
is a group of magnets containing at least two magnets, and each group of
magnets has two
ends, and the magnets in each group of magnets overlap each other to produce a
combined
magnetic field, and each of the magnets in a group of magnets has a north pole
and a south
pole, and the south pole of any particular magnet is either physically
proximate to one of the
two ends, or to the north pole of another magnet in the same group of magnets,
and the north
pole of any particular magnet is either physically proximate to one of the two
ends, or to the
south pole of another magnet in the same group of magnets.
[0034] In one embodiment, the piezoelectric actuators are electrically
connected to the power
supply with a capacitive connection, such that at least one of the
piezoelectric actuators form a
first terminal of a capacitor, and a capacitive surface electrically connected
to the power supply
forms a second terminal of the capacitor, the capacitive surface separated
from at least one
piezoelectric actuator by a gap, such that when the second capacitive surface
is energized by
the power supply, a current is induced in at least one piezoelectric actuator,
energizing at least
one piezoelectric actuator.
[0035] In one embodiment, the magnetic bearing further comprises e) a
frequency controller,
the frequency controller controlling the power supply such that the frequency
controller can
cause the power supply to apply a positive voltage or a negative voltage to
one or more of the
piezoelectric actuators.
[0036] In one embodiment, the magnetic bearing further comprises f) a heat
sensor, the heat
sensor linked to the frequency controller controlling the power supply such
that the frequency
controller can cause the power supply to adjust the positive voltage or the
negative voltage of
the piezoelectric actuators in response to a detected temperature.
[0037] In one embodiment, the magnetic bearing further comprises f) a gap
sensor, the gap
sensor linked to the frequency controller controlling the power supply such
that the frequency
controller can cause the power supply to adjust the positive voltage or the
negative voltage of
the piezoelectric actuators in response to a change in the size of the
variable gap.
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[0038] In one embodiment, the magnetic bearing further comprises f) an
acceleration sensor,
the acceleration sensor linked to the frequency controller controlling the
power supply such
that the frequency controller can cause the power supply to adjust the
positive voltage or the
negative voltage of the piezoelectric actuators in response to a detected
acceleration.
[0039] In one embodiment, the magnetic bearing further comprises f) a gap
sensor, the gap
sensor linked to the frequency controller controlling the power supply such
that the frequency
controller can cause the power supply to adjust the positive voltage or the
negative voltage of
the piezoelectric actuators in response to a change in the size of the
variable gap.
[0040] Generally, among the many objectives of the present disclosure is the
provision of an
electric stepper motor. One objective is the provision of an electric stepper
motor which uses
piezoelectric impulse and permanent magnets as a source of generating
mechanical energy
from electrical energy and rotating the motor through a very precise rotation.
Another objective
is the provision of an electric stepper motor which does not use
electromagnets and is therefore
more efficient and economical to construct. Another objective is the provision
of an electric
stepper motor which does not use electromagnets and is therefore more
efficient and
economical to operate. Yet another objective is the provision of an electric
stepper motor which
does not use electromagnets and is therefore more durable and easier to
maintain. Still another
objective of an electric stepper motor which does not use electromagnets and
is therefore lighter
in weight than a traditional electric stepper motor of equivalent output.
Other advantages and
objectives of the electric stepper motor will become clear by reading the
application and the
disclosures herein.
[0041] In accordance with another aspect of the present disclosure, there is
provided an electric
stepper motor comprising: a) at least one group of piezoelectric actuators,
the at least one group
of piezoelectric actuators comprising at least one piezoelectric actuator, all
of the piezoelectric
actuators electrically connected to a switching power supply; b) a group of
actuator magnets,
the group of actuator magnets comprising at least one actuator magnet, each of
the at least one
piezoelectric actuators mechanically affixed to the group of actuator magnets;
c) a group of
response magnets, the group of response magnets physically opposed to the
first plurality of
piezoelectric elements separated by a variable gap having a size, such that
when one or more
of the plurality of piezoelectric actuators are energized by the switching
power supply, the size
of the variable gap changes; d) a motor assembly including a mobile assembly
and a static
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assembly, the mobile assembly mechanically affixed to either the group of
actuator magnets or
the group of response magnets, the static assembly mechanically affixed to
whichever of the
group of actuator magnets or the group of response magnets the mobile assembly
is not
mechanically affixed, such that when the size of the variable gap changes, a
magnetic force is
exerted on the mobile assembly, causing the mobile assembly to move relative
to the static
assembly; and e) a frequency controller, electrically connected to the
switching power supply,
which causes the switching power supply to energize, and then de-energize,
some or all of the
piezoelectric actuators a fixed number of times such that the mobile assembly
moves a target
fixed distance.
[0042] In one embodiment, there is one and only one group of piezoelectric
actuators, and the
one and only one group of piezoelectric actuators comprises one and only one
piezoelectric
actuator, and there is one and only one group of actuator magnets, and the one
and only one
group of actuator magnets comprises two actuator magnets.
[0043] In one embodiment, the group of response magnets comprises a single
piece of
magnetic material, the single piece of magnetic material having a plurality of
magnetic regions,
each magnetic region having a local north pole and a local south pole.
[0044] In one embodiment, the electric stepper motor further comprises f) a
group of actuator
capacitor plates, the group of actuator capacitor plates comprising at least
one actuator
capacitor plate, the group of actuator capacitor plates connected to the
switching power supply
and mechanically affixed to a housing of the electric stepper motor such that
when the group
of capacitor plates are energized by the switching power supply, they form a
capacitor circuit
with one or more of the piezoelectric actuators, causing a current to be
induced in the
piezoelectric actuators in the capacitor circuit.
[0045] In one embodiment, there are two groups of piezoelectric actuators,
further comprising:
e) a first group of piezoelectric actuators forming a group of stator
piezoelectric actuators, each
of the stator piezoelectric actuators mechanically affixed to a stator magnet;
and f) a second
group of piezoelectric actuators forming a group of rotor piezoelectric
actuators, each of the
rotor piezoelectric actuators mechanically affixed to a rotor magnet.
[0046] In one embodiment, the electric stepper motor further comprises g) a
group of actuator
capacitor plates, the group of actuator capacitor plates comprising at least
one actuator
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capacitor plate, the group of actuator capacitor plates connected to the
switching power supply
and mechanically affixed to a housing of the electric stepper motor such that
when the group
of capacitor plates are energized by the switching power supply, they form a
capacitor circuit
with one or more of the piezoelectric actuators, causing a current to be
induced in the
piezoelectric actuators in the capacitor circuit.
[0047] In one embodiment, each group of actuator magnets has two ends, and the
actuator
magnets in each group of actuator magnets overlap each other to produce a
combined actuator
magnetic field, and each of the actuator magnets in a group of actuator
magnets has a north
pole and a south pole, and the south pole of any particular actuator magnet is
either physically
proximate to one of the two ends, or to the north pole of another actuator
magnet in the group
of actuator magnets, and the north pole of any particular actuator magnet is
either physically
proximate to one of the two ends, or to the south pole of another actuator
magnet in the group
of actuator magnets.
[0048] In one embodiment, the actuator magnets in each group of actuator
magnets are secured
by an adhesive, the adhesive securing the actuator magnets in a fixed
orientation.
[0049] In one embodiment, the electric stepper motor further comprises e) a
group of elastic
members, the elastic members mechanically affixed to at least one
piezoelectric actuator such
that when the piezoelectric actuator is energized, the elastic member will
acquire an elastic
potential energy, and when the piezoelectric actuator is de-energized, the
elastic potential
energy will be converted into an elastic force which will push against the
piezoelectric actuator.
[0050] In one embodiment, the electric stepper motor further comprises e) a
group of elastic
members, the elastic members mechanically affixed to at least one
piezoelectric actuator such
that when the piezoelectric actuator is energized, the elastic member will
acquire an elastic
potential energy, and when the piezoelectric actuator is de-energized, the
elastic potential
energy will be converted into an elastic force which will push against the
piezoelectric actuator.
[0051] In one embodiment, the electric stepper motor further comprises f) a
group of elastic
members, the elastic members mechanically affixed to at least one
piezoelectric actuator such
that when the piezoelectric actuator is energized, the elastic member will
acquire an elastic
potential energy, and when the piezoelectric actuator is de-energized, the
elastic potential
energy will be converted into an elastic force which will push against the
piezoelectric actuator.
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[0052] In accordance with another aspect of the present disclosure, there is
provided an electric
stepper motor comprising: a) at least one group of static piezoelectric
actuators, the at least
one group of static piezoelectric actuators comprising at least one static
piezoelectric actuator,
all of the static piezoelectric actuators electrically connected to a
switching power supply; b)
a group of static magnets, the group of static magnets comprising at least one
static magnet,
each of the at least one static piezoelectric actuators mechanically affixed
to the group of static
magnets; c) at least one group of mobile piezoelectric actuators, the at least
one group of
mobile piezoelectric actuators comprising at least one mobile piezoelectric
actuator, all of the
mobile piezoelectric actuators electrically connected to the switching power
supply; d) a group
of mobile magnets, the group of mobile magnets comprising at least one mobile
magnet, each
of the at least one mobile piezoelectric actuators mechanically affixed to the
group of mobile
magnets; e) a motor assembly having a mobile assembly and a static assembly,
the mobile
assembly mechanically affixed to the group of mobile piezoelectric actuators,
the static
assembly mechanically affixed to the group of static piezoelectric actuators,
such that there is
a variable gap having a size between the group of mobile magnets and the group
of static
magnets and when the size of the variable gap changes, a magnetic force is
exerted on the
mobile assembly, causing the mobile assembly to move relative to the static
assembly; and f)
a frequency controller, electrically connected to the switching power supply,
which causes the
switching power supply to energize, and then de-energize, some or all of the
static piezoelectric
actuators and/or some or all of the mobile piezoelectric actuators a fixed
number of times such
that the mobile assembly moves a target fixed distance.
[0053] In one embodiment, the electric stepper motor further comprises g) a
group of elastic
members, the elastic members mechanically affixed to at least one of the
static or mobile
piezoelectric actuator such that when the piezoelectric actuator is energized,
the elastic member
will acquire an elastic potential energy, and when the piezoelectric actuator
is de-energized,
the elastic potential energy will be converted into an elastic force which
will push against the
piezoelectric actuator.
[0054] In one embodiment, the electric stepper motor further comprises f) a
group of energizer
capacitor plates, the group of energizer capacitor plates comprising at least
one energizer
capacitor plate, the group of actuator capacitor plates connected to the
switching power supply
and mechanically affixed to a housing of the electric stepper motor such that
when the group
of capacitor plates are energized by the switching power supply, they form a
capacitor circuit
3021P-MBE-CAD1 13
Date Recue/Date Received 2022-02-28
with one or more of the piezoelectric actuators, causing a current to be
induced in the
piezoelectric actuators in the capacitor circuit.
[0055] In one embodiment, each group of static magnets and/or each group of
mobile magnets
is a group of magnets containing at least two magnets, and each group of
magnets has two
.. ends, and the magnets in each group of magnets overlap each other to
produce a combined
magnetic field, and each of the magnets in a group of magnets has a north pole
and a south
pole, and the south pole of any particular magnet is either physically
proximate to one of the
two ends, or to the north pole of another magnet in the same group of magnets,
and the north
pole of any particular magnet is either physically proximate to one of the two
ends, or to the
south pole of another magnet in the same group of magnets.
[0056] In one embodiment, the piezoelectric actuators are electrically
connected to the
switching power supply with a capacitive connection, such that at least one of
the piezoelectric
actuators form a first terminal of a capacitor, and a capacitive surface
electrically connected to
the switching power supply forms a second terminal of the capacitor, the
capacitive surface
separated from at least one piezoelectric actuator by a gap, such that when
the second capacitive
surface is energized by the switching power supply, a current is induced in at
least one
piezoelectric actuator, energizing at least one piezoelectric actuator.
[0057] In one embodiment, the piezoelectric actuators are electrically
connected to the
switching power supply with a capacitive connection, such that a first
capacitive surface
electrically connected to at least one of the piezoelectric actuators forms a
first terminal of a
capacitor, and a second capacitive surface electrically connected to the
switching power supply
forms a second terminal of the capacitor, the first and second terminals
separated by a gap,
such that when the second capacitive surface is energized by the switching
power supply, a
current is induced in the first capacitive surface, energizing at least one
piezoelectric actuator.
.. [0058] In one embodiment, the electric stepper motor further comprises f) a
rotary position
sensor which can detect an absolute rotary position of the mobile assembly.
[0059] In one embodiment, the rotary position sensor is operably attached to
the frequency
controller such that the frequency controller can use the absolute rotary
position of the mobile
assembly to determine when to switch the switching power supply on and off
such that the
.. mobile assembly moves the target fixed distance.
3021P-MBE-CAD1 1 4
Date Recue/Date Received 2022-02-28
[0060] Generally, among the many objectives of the present disclosure is the
provision of an
electric motor with positional sensing. One objective is the provision of an
electric motor with
positional sensing which uses piezoelectric impulse and permanent magnets as a
source of
generating mechanical energy from electrical energy. Another objective is the
provision of an
electric motor with positional sensing which does not use electromagnets and
is therefore more
efficient and economical to construct. Another objective is the provision of
an electric motor
with positional sensing which does not use electromagnets and is therefore
more efficient and
economical to operate. Yet another objective is the provision of an electric
motor with
positional sensing which does not use electromagnets and is therefore more
durable and easier
to maintain. Still another objective is the provision of an electric motor
with positional sensing
which does not use electromagnets and is therefore lighter in weight than a
traditional brushless
electric motor of equivalent output. The disclosure also provides an electric
motor with
positional sensing which does not require external detection means and
produces a precise
measurement of the position and/or motion of the motor. Other advantages and
objectives of
the electric motor with positional sensing will become clear by reading the
application and the
disclosures herein.
[0061] In accordance with another aspect of the present disclosure, there is
provided an electric
motor with positional sensing comprising: a) at least one group of
piezoelectric actuators, the
at least one group of piezoelectric actuators comprising at least one
piezoelectric actuator, all
of the piezoelectric actuators electrically connected to a power supply; b) a
group of actuator
magnets, the group of actuator magnets comprising at least one actuator
magnet, each of the at
least one piezoelectric actuators mechanically affixed to the group of
actuator magnets; c) a
group of response magnets, the group of response magnets physically opposed to
the first
plurality of piezoelectric elements separated by a variable gap having a size,
such that when
one or more of the plurality of piezoelectric actuators are energized by the
power supply, the
size of the variable gap changes; d) a motor assembly including a mobile
assembly and a static
assembly, the mobile assembly mechanically affixed to either the group of
actuator magnets or
the group of response magnets, the static assembly mechanically affixed to
whichever of the
group of actuator magnets or the group of response magnets the mobile assembly
is not
mechanically affixed, such that when the size of the variable gap changes, a
magnetic force is
exerted on the mobile assembly, causing the mobile assembly to move relative
to the static
assembly; and e) a counting device, which counts a number of times that one or
more of the
3021P-MBE-CAD1 15
Date Recue/Date Received 2022-02-28
actuator magnets passes by one or more of the response magnets in turn from a
known starting
position, such that a relative position of the mobile assembly relative to the
known starting
position can be determined by using a ratio of an angle swept by a single
actuator magnet or a
single response magnet to a total diameter of the static assembly, the
counting device being
able to count the number of times whether the mobile assembly moves relative
to the static
assembly due to the plurality of piezoelectric actuators being energized by
the power supply or
due to an external load which imparts an external torque onto one or both of
the static assembly
or the mobile assembly.
[0062] In one embodiment, the counting device counts the number of times by
detecting a
back-current when the piezoelectric actuators are not energized by the power
supply, the back
current caused by the piezoelectric actuators being compressed as the actuator
magnets move
relative to the response magnets due to the external torque.
[0063] In one embodiment, the group of response magnets comprises a single
piece of
magnetic material, the single piece of magnetic material having a plurality of
magnetic regions,
each magnetic region having a local north pole and a local south pole.
[0064] In one embodiment, the electric motor with positional sensing comprises
f) a group of
actuator capacitor plates, the group of actuator capacitor plates comprising
at least one actuator
capacitor plate, the group of actuator capacitor plates connected to the power
supply and
mechanically affixed to a housing of the electric motor with positional
sensing such that when
the group of capacitor plates are energized by the power supply, they form a
capacitor circuit
with one or more of the piezoelectric actuators, causing a current to be
induced in the
piezoelectric actuators in the capacitor circuit.
[0065] In one embodiment, there are two groups of piezoelectric actuators,
further comprising:
e) a first group of piezoelectric actuators forming a group of stator
piezoelectric actuators, each
of the stator piezoelectric actuators mechanically affixed to a stator magnet;
and f) a second
group of piezoelectric actuators forming a group of rotor piezoelectric
actuators, each of the
rotor piezoelectric actuators mechanically affixed to a rotor magnet.
[0066] In one embodiment, the electric motor with positional sensing comprises
g) a group of
actuator capacitor plates, the group of actuator capacitor plates comprising
at least one actuator
capacitor plate, the group of actuator capacitor plates connected to the power
supply and
3021P-MBE-CAD1 1 6
Date Recue/Date Received 2022-02-28
mechanically affixed to a housing of the electric motor with positional
sensing such that when
the group of capacitor plates are energized by the power supply, they form a
capacitor circuit
with one or more of the piezoelectric actuators, causing a current to be
induced in the
piezoelectric actuators in the capacitor circuit.
[0067] In one embodiment, each group of actuator magnets has two ends, and the
actuator
magnets in each group of actuator magnets overlap each other to produce a
combined actuator
magnetic field, and each of the actuator magnets in a group of actuator
magnets has a north
pole and a south pole, and the south pole of any particular actuator magnet is
either physically
proximate to one of the two ends, or to the north pole of another actuator
magnet in the group
.. of actuator magnets, and the north pole of any particular actuator magnet
is either physically
proximate to one of the two ends, or to the south pole of another actuator
magnet in the group
of actuator magnets.
[0068] In one embodiment, actuator magnets in each group of actuator magnets
are secured by
an adhesive, the adhesive securing the actuator magnets in a fixed
orientation.
[0069] In one embodiment, there are two groups of piezoelectric actuators,
further comprising:
f) a first group of piezoelectric actuators forming a group of stator
piezoelectric actuators, each
of the stator piezoelectric actuators mechanically affixed to a stator magnet;
and g) a second
group of piezoelectric actuators forming a group of rotor piezoelectric
actuators, each of the
rotor piezoelectric actuators mechanically affixed to a rotor magnet.
[0070] In one embodiment, each group of actuator magnets has two ends, and the
actuator
magnets in each group of actuator magnets overlap each other to produce a
combined actuator
magnetic field, and each of the actuator magnets in a group of actuator
magnets has a north
pole and a south pole, and the south pole of any particular actuator magnet is
either physically
proximate to one of the two ends, or to the north pole of another actuator
magnet in the group
of actuator magnets, and the north pole of any particular actuator magnet is
either physically
proximate to one of the two ends, or to the south pole of another actuator
magnet in the group
of actuator magnets.
[0071] In one embodiment, the actuator magnets in each group of actuator
magnets are secured
by an adhesive, the adhesive securing the actuator magnets in a fixed
orientation.
3021P-MBE-CAD1 1 7
Date Recue/Date Received 2022-02-28
[0072] In one embodiment, the electric motor with positional sensing further
comprises e) a
group of elastic members, the elastic members mechanically affixed to at least
one piezoelectric
actuator such that when the piezoelectric actuator is energized, the elastic
member will acquire
an elastic potential energy, and when the piezoelectric actuator is de-
energized, the elastic
potential energy will be converted into an elastic force which will push
against the piezoelectric
actuator.
[0073] In one embodiment, the electric motor with positional sensing further
comprises e) a
group of elastic members, the elastic members mechanically affixed to at least
one piezoelectric
actuator such that when the piezoelectric actuator is energized, the elastic
member will acquire
an elastic potential energy, and when the piezoelectric actuator is de-
energized, the elastic
potential energy will be converted into an elastic force which will push
against the piezoelectric
actuator.
[0074] In one embodiment, the electric motor with positional sensing further
comprises f) a
group of elastic members, the elastic members mechanically affixed to at least
one piezoelectric
actuator such that when the piezoelectric actuator is energized, the elastic
member will acquire
an elastic potential energy, and when the piezoelectric actuator is de-
energized, the elastic
potential energy will be converted into an elastic force which will push
against the piezoelectric
actuator.
[0075] In one embodiment, the electric motor with positional sensing further
comprises e) a
group of elastic members, the elastic members mechanically affixed to at least
one piezoelectric
actuator such that when the piezoelectric actuator is energized, the elastic
member will acquire
an elastic potential energy, and when the piezoelectric actuator is de-
energized, the elastic
potential energy will be converted into an elastic force which will push
against the piezoelectric
actuator.
[0076] In one embodiment, the piezoelectric actuators are electrically
connected to the power
supply with a capacitive connection, such that at least one of the
piezoelectric actuators form a
first terminal of a capacitor, and a capacitive surface electrically connected
to the power supply
forms a second terminal of the capacitor, the capacitive surface separated
from at least one
piezoelectric actuator by a gap, such that when the second capacitive surface
is energized by
3021P-MBE-CAD1 1 8
Date Recue/Date Received 2022-02-28
the power supply, a current is induced in at least one piezoelectric actuator,
energizing at least
one piezoelectric actuator.
[0077] In accordance with another aspect of the present disclosure, there is
provided an electric
motor with positional sensing comprising: a) at least one group of
piezoelectric actuators, the
at least one group of piezoelectric actuators comprising at least one
piezoelectric actuator, all
of the piezoelectric actuators electrically connected to a power supply; b) a
group of actuator
magnets, the group of actuator magnets comprising at least one actuator
magnet, each of the at
least one piezoelectric actuators mechanically affixed to the group of
actuator magnets; c) a
group of response magnets, the group of response magnets physically opposed to
the first
plurality of piezoelectric elements separated by a variable gap having a size,
such that when
one or more of the plurality of piezoelectric actuators are energized by the
power supply, the
size of the variable gap changes; d) a motor assembly including a mobile
assembly and a static
assembly, the mobile assembly mechanically affixed to either the group of
actuator magnets or
the group of response magnets, the static assembly mechanically affixed to
whichever of the
group of actuator magnets or the group of response magnets the mobile assembly
is not
mechanically affixed, such that when the size of the variable gap changes, a
magnetic force is
exerted on the mobile assembly, causing the mobile assembly to move relative
to the static
assembly; and e) an induced-current sensor, which detects a back-current, the
back-current
being induced in the piezoelectric actuators when due to an external load
imparting an external
torque onto one or both of the static assembly or the mobile assembly, the
mobile assembly
moves relative to the static assembly.
[0078] In one embodiment, the electric motor with positional sensing further
comprises f) a
calibration memory device, which can store a plurality of calibration back-
current values, the
calibration back-current values obtained by using the induced-current sensor
to measure the
back-current at a plurality of times.
[0079] In one embodiment, the electric motor with positional sensing further
comprises g) a
calibration load, the calibration load comprising an external driving device
which can be
removably connected to the electric motor to impart a controllable external
torque onto one or
the other of the mobile assembly or the static assembly.
3021P-MBE-CAD1 19
Date Recue/Date Received 2022-02-28
[0080] In one embodiment, the calibration memory device stores a first
plurality of calibration
back-current values measured when the piezoelectric actuators are not
energized by the power
supply, and a second plurality of calibration back-current values measured
when the
piezoelectric actuators are energized by the power supply.
[0081] In one embodiment, the calibration memory device stores a first
plurality of calibration
back-current values measured when the piezoelectric actuators are not
energized by the power
supply, and a second plurality of calibration back-current values measured
when the
piezoelectric actuators are energized by the power supply.
[0082] In one embodiment, the electric motor with positional sensing further
comprises g) a
position determining device, the position determining device dynamically
receiving a plurality
of operating back-current values from the induced-current sensor, the position
determining
device comparing the plurality of operating back-current values to the
plurality of calibration
back-current values to determine a relative position of the mobile assembly to
the static
assembly.
[0083] In one embodiment, the electric motor with positional sensing further
comprises h) a
position determining device, the position determining device dynamically
receiving a plurality
of operating back-current values from the induced-current sensor, the position
determining
device comparing the plurality of operating back-current values to the
plurality of calibration
back-current values to determine a relative position of the mobile assembly to
the static
assembly.
[0084] In one embodiment, the calibration memory device stores a first
plurality of calibration
back-current values measured when the piezoelectric actuators are not
energized by the power
supply, and a second plurality of calibration back-current values measured
when the
piezoelectric actuators are energized by the power supply, and the position
determining device
compares the first plurality of calibration back-current values and the second
plurality of
calibration values to the plurality of operating back-current values to
determine a relative
position of the mobile assembly to the static assembly.
[0085] In one embodiment, the calibration memory device stores a first
plurality of calibration
back-current values measured when the piezoelectric actuators are not
energized by the power
supply, and a second plurality of calibration back-current values measured
when the
3021P-MBE-CAD1 20
Date Recue/Date Received 2022-02-28
piezoelectric actuators are energized by the power supply, and the position
determining device
compares the first plurality of calibration back-current values and the second
plurality of
calibration values to the plurality of operating back-current values to
determine a relative
position of the mobile assembly to the static assembly.
[0086] In one embodiment, the calibration memory device stores a first
plurality of calibration
back-current values measured when the piezoelectric actuators are not
energized by the power
supply, and a second plurality of calibration back-current values measured
when the
piezoelectric actuators are energized by the power supply, and the first
plurality of calibration
back-current values and the second plurality of calibration back-current
values are combined
into a plurality of average calibration back-current values, and the position
determining device
compares the plurality of average calibration back-current values to the
plurality of operating
back-current values to determine a relative position of the mobile assembly to
the static
assembly.
[0087] In one embodiment, the electric motor with positional sensing further
comprises a) a
group of elastic members, the elastic members mechanically affixed to at least
one of the static
or mobile piezoelectric actuator such that when the piezoelectric actuator is
energized, the
elastic member will acquire an elastic potential energy, and when the
piezoelectric actuator is
de-energized, the elastic potential energy will be converted into an elastic
force which will
push against the piezoelectric actuator.
[0088] In one embodiment, the electric motor with positional sensing further
comprises f) a
group of energizer capacitor plates, the group of energizer capacitor plates
comprising at least
one energizer capacitor plate, the group of actuator capacitor plates
connected to the power
supply and mechanically affixed to a housing of the electric motor with
positional sensing such
that when the group of capacitor plates are energized by the power supply,
they form a capacitor
circuit with one or more of the piezoelectric actuators, causing a current to
be induced in the
piezoelectric actuators in the capacitor circuit.
[0089] In one embodiment, each group of static magnets and/or each group of
mobile magnets
is a group of magnets containing at least two magnets, and each group of
magnets has two
ends, and the magnets in each group of magnets overlap each other to produce a
combined
magnetic field, and each of the magnets in a group of magnets has a north pole
and a south
3021P-MBE-CAD1 21
Date Recue/Date Received 2022-02-28
pole, and the south pole of any particular magnet is either physically
proximate to one of the
two ends, or to the north pole of another magnet in the same group of magnets,
and the north
pole of any particular magnet is either physically proximate to one of the two
ends, or to the
south pole of another magnet in the same group of magnets.
[0090] In one embodiment, the piezoelectric actuators are electrically
connected to the power
supply with a capacitive connection, such that at least one of the
piezoelectric actuators form a
first terminal of a capacitor, and a capacitive surface electrically connected
to the power supply
forms a second terminal of the capacitor, the capacitive surface separated
from at least one
piezoelectric actuator by a gap, such that when the second capacitive surface
is energized by
the power supply, a current is induced in at least one piezoelectric actuator,
energizing at least
one piezoelectric actuator.
BRIEF DESCRIPTION OF THE FIGURES
[0091] Several embodiments of the present disclosure will be provided, by way
of examples
only, with reference to the appended drawings, wherein:
[0092] FIGURE 1 depicts a perspective view of a magnetic bearing, in
accordance with one
aspect of the disclosure;
[0093] FIGURE 2 depicts an overhead view of a first alternate embodiment of
the magnetic
bearing depicted in Figure 1;
[0094] FIGURE 3 depicts a cutaway perspective view of the first alternate
embodiment of the
magnetic bearing depicted in Figure 2;
[0095] FIGURE 4 depicts a detail view of the interfacing stator and rotor
elements of the first
alternate embodiment of the magnetic bearing depicted in Figures 2 and 3;
[0096] FIGURE 5 depicts an exploded perspective view of the first alternate
embodiment
magnetic bearing assembly depicted in Figures 2 to 4;
[0097] FIGURE 6 depicts an overhead view of a second alternate embodiment of
the magnetic
bearing depicted in Figure 1;
3021P-MBE-CAD1 22
Date Recue/Date Received 2022-02-28
[0098] FIGURE 7 depicts an exploded perspective view of the second alternate
magnetic
bearing assembly depicted in Figure 6;
[0099] FIGURE 8 depicts an alternate exploded perspective view of the second
alternate
magnetic bearing assembly depicted in Figures 6 and 7;
[00100] FIGURE 9 depicts a cutaway view of the second alternate magnetic
bearing
assembly depicted in Figures 6 to 8;
[00101] FIGURE 10 depicts a perspective view of a third alternate
embodiment of the
magnetic bearing depicted in Figure 1;
[00102] FIGURE 11 depicts a cross-sectional perspective view of the
third alternate
embodiment of the magnetic bearing depicted in Figure 10;
[00103] FIGURE 12 depicts a perspective view of an electric stepper
motor, in
accordance with another aspect of the disclosure;
[00104] FIGURE 13 depicts an overhead view of a first alternate
embodiment of the
electric stepper motor depicted in Figure 12;
[00105] FIGURE 14 depicts a cutaway perspective view of the first alternate
embodiment of the electric stepper motor depicted in Figure 13;
[00106] FIGURE 15 depicts a detail view of the interfacing stator and
rotor elements of
the first alternate embodiment of the electric stepper motor depicted in
Figures 13 and 14;
[00107] FIGURE 16 depicts an exploded perspective view of the first
alternate
embodiment electric stepper motor assembly depicted in Figures 13 to 15;
[00108] FIGURE 17 depicts an overhead view of a second alternate
embodiment of the
electric stepper motor depicted in Figure 12;
[00109] FIGURE 18 depicts an exploded perspective view of the second
alternate
electric stepper motor assembly depicted in Figure 17;
[00110] FIGURE 19 depicts an alternate exploded perspective view of the
second
alternate electric stepper motor assembly depicted in Figures 17 and 18;
3021P-MBE-CAD1 23
Date Recue/Date Received 2022-02-28
[00111] FIGURE 20 depicts a cutaway view of the second alternate
electric stepper
motor assembly depicted in Figures 17 to 19;
[00112] FIGURE 21 depicts a perspective view of a third alternate
embodiment of the
electric stepper motor depicted in Figure 12;
[00113] FIGURE 22 depicts a cross-sectional perspective view of the third
alternate
embodiment of the electric stepper motor depicted in Figure 21;
[00114] FIGURE 23 depicts a perspective view of an electric motor with
positional
sensing in accordance with another aspect of the disclosure;
[00115] FIGURE 24 depicts an overhead view of a first alternate
embodiment of the
electric motor with positional sensing depicted in Figure 23;
[00116] FIGURE 25 depicts a cutaway perspective view of the first
alternate
embodiment of the electric motor with positional sensing depicted in Figure
24;
[00117] FIGURE 26 depicts a detail view of the interfacing stator and
rotor elements of
the first alternate embodiment electric motor with positional sensing depicted
in Figures 24
and 25;
[00118] FIGURE 27 depicts an exploded perspective view of the first
alternate
embodiment electric motor with positional sensing assembly depicted in Figures
24 to 26;
[00119] FIGURE 28 depicts an overhead view of a second alternate
embodiment of the
electric motor with positional sensing depicted in Figure 23;
[00120] FIGURE 29 depicts an exploded perspective view of the second
alternate
electric motor with positional sensing assembly depicted in Figure 28;
[00121] FIGURE 30 depicts an alternate exploded perspective view of the
second
alternate electric motor with positional sensing assembly depicted in Figures
28 and 29;
[00122] FIGURE 31 depicts a cutaway view of the second alternate
electric motor with
positional sensing assembly depicted in Figures 28 to 30;
3021P-MBE-CAD1 24
Date Recue/Date Received 2022-02-28
[00123] FIGURE 32 depicts a perspective view of a third alternate
embodiment of the
electric motor with positional sensing depicted in Figure 23; and
[00124] FIGURE 33 depicts a cross-sectional perspective view of the
third alternate
embodiment of the electric motor with positional sensing depicted in Figure
32.
[00125] In the figures, like reference numerals denote like parts unless
the contrary is
indicated, as will become apparent from the detailed description.
[00126] Elements in the several figures are illustrated for simplicity
and clarity and have
not necessarily been drawn to scale. For example, the dimensions of some of
the elements in
the figures may be emphasized relative to other elements for facilitating
understanding of the
various presently disclosed embodiments. Also, common, but well-understood
elements that
are useful or necessary in commercially feasible embodiments are often not
depicted in order
to facilitate a less obstructed view of these various embodiments of the
present disclosure.
DETAILED DESCRIPTION
[00127] Various implementations and aspects of the specification will
be described with
reference to details discussed below. The following description and drawings
are illustrative of
the specification and are not to be construed as limiting the specification.
Numerous specific
details are described to provide a thorough understanding of various
implementations of the
present specification. However, in certain instances, well-known or
conventional details are
not described in order to provide a concise discussion of implementations of
the present
.. specification.
[00128] Reference will now be made in detail to several embodiments of
the disclosure
that are illustrated in accompanying drawings. Whenever possible, the same or
similar
reference numerals are used in the drawings and the description to refer to
the same or like
parts or steps. The drawings are in simplified form and are not to precise
scale. For purposes
of convenience and clarity only, directional terms such as top, bottom, left,
right, up, down,
over, above, below, beneath, rear, and front, can be used with respect to the
drawings. These
and similar directional terms are not to be construed to limit the scope of
the disclosure in any
manner. The words attach, connect, couple, and similar terms with their
inflectional
3021P-MBE-CAD1 25
Date Recue/Date Received 2022-02-28
morphemes do not necessarily denote direct or intermediate connections, but
can also include
connections through mediate elements or devices.
[00129] It should be noted that the sizes and configurations of the
preferred
embodiment(s) described in the drawings are exaggerated for clarity of
disclosure: in actual
practice, the tolerances between the elements of embodiments of the disclosure
would be much
more precise. It is a feature of the disclosure that it allows such very
precise tolerances.
[00130] Various aspects of this application include magnetic bearings
and electric
motors, which will now be described.
MAGNETIC BEARING
[00131] In acccordance with one aspect of the disclosure, a magnetic
bearing 10 will
now be described in terms of a brushless electric motor such as is disclosed
in U.S. Patent
Application No. 16/941,477 filed July 28, 2020. The distinction between such a
brushless
electric motor and a magnetic bearing, in the context of this application, is
that the bearing is
active even when the motor is not energized, with these additional features:
[00132] If and when the load cannot be rotated at a desired rate by an
external driving
force, the piezoelectric actuators can be powered to add additional torque and
serve as an
auxiliary source of power.
[00133] If and when the load begins to rotate faster than is desired,
the piezoelectric
actuators can be powered to provide torque in the opposite direction of
rotation, slowing the
rotation of the load.
[00134] The piezoelectric actuators can be used to stabilize the spin
of the load without
adding any net torque or "drive."
[00135] The piezoelectric actuators can be used to recover some of the
energy from the
rotation of the load as they will provide a current if the load rotates
freely.
[00136] For purposes of this aspect of the disclosure, piezoelectric
actuators are
described as being "electrically connected" to a power supply. Such a
connection can be made
via physical conductors (wires, PCB conductive paths, conductive inks, et
cetera) or by any
3021P-MBE-CAD1 26
Date Recue/Date Received 2022-02-28
other reasonable means that allows the power supply to supply energy to the
piezoelectric
actuators and causes the piezoelectric effect to change the dimensions of the
piezoelectric
actuators. This includes, but is not limited to, electromagnetic induction or
transfer by
capacitance. It is required that the means of electrical connection be able to
switch the
.. piezoelectric actuators on and off and/or apply a current flow in one
direction and then in the
other direction fast enough to allow the motor to operate, as will be made
clear in the
specification below. This will be referred to generally as "rise" time ¨ the
period of time it
takes to energize the piezoelectric actuator and/or the capacitator powering
it ¨ and the "fall"
time ¨ the period of time it takes to deenergize the piezoelectric actuator
and/or the capacitor
powering it.
[00137] For purposes of this aspect of the disclosure, the magnetic
bearing, as embodied
in a "motor," will generally have a group of components which remains static
relative to a load,
and a second group of components which will move relative to the first group
of components.
The first group of components will be referred to collectively as a stator
assembly, and the
second group referred to collectively as a rotor assembly. Prefixing a
component with the word
"rotor" or "stator" indicates which group of components it belongs to in the
embodiment/configuration which is currently being described. Piezoelectric
actuators in the
stator assembly are stator piezoelectric actuators (or simply stator
actuators) and magnets
affixed to stator piezoelectric actuators are stator magnets, and vice versa
with regard to the
rotor assembly.
[00138] At the same time, for purposes of this aspect of the
disclosure, magnets can also
be described as falling into one or both of two distinct types independent of
whether they are
part of the stator assembly or the rotor assembly. Actuator magnets are
magnets which have/are
having force imposed upon them by a piezoelectric actuator. Response magnets
are magnets
which have/are having force imposed upon them via magnetic field interactions
with actuator
magnets. If only one group of magnets is affixed to piezoelectric actuators,
those are the
actuator magnets, and the rest of the magnets in the motor are response
magnets. If multiple
groups of magnets are affixed to piezoelectric actuators, magnets affixed to a
piezoelectric
actuator which is being energized and causing it to impose force on those
magnets are actuator
magnets, and magnets which are not so affixed, or which are affixed to a
piezoelectric actuator
which is not being energized, are response magnets. It is possible for any
given magnet to be
an actuator magnet or a response magnet or both at any given time depending on
the bearing
3021P-MBE-CAD1 27
Date Recue/Date Received 2022-02-28
controller's configuration and energization of the piezoelectric actuators. A
rotor magnet or a
stator magnet may at any time be an actuator magnet, a response magnet, or
both.
[00139] By referring to FIGURE 1, the basic nature of the magnetic
bearing 10 can be
easily understood. Outer rotor housing 11 surrounds optional mechanical
bearing 12 which is
free to rotate on balls 13, which bear the load between the motor and whatever
it is mounted in
and whatever it is driving.
[00140] It should be clearly understood that in the primary
configuration of the magnetic
bearing, the mechanical bearing elements (12 and 13) are provided only for
supplemental
bearing capability. They are not required. The magnetic bearing can function
without them.
[00141] Inner rotor element 14 has multiple rotor magnets 15 having rotor
north poles
15a and rotor south poles 15b. Any suitable magnet may be used for rotor
magnets 15,
including but not limited to rare-earth magnets, ferromagnets, and/or ceramic
magnets
containing ferromagnetic and/or rare-earth magnetic particles. Electromagnets
may also be
used. If electromagnets are used, it is optional, but neither preferred nor
required, to allow them
to reverse polarity as driven by a solid-state commutator of the type found in
traditional
brushless electric motors.
[00142] Stator assembly 19 consists of central hub 18, which supports
multiple stator
piezoelectric actuators 17. Stator piezoelectric actuators 17 have a magnet
mount end 17a and
a hub end 17b. Stator piezoelectric actuators 17 are connected to a switching
power supply (not
shown) which can energize the stator piezoelectric actuators at any reasonable
driving
frequency. When the stator piezoelectric actuators are energized, they expand,
using the
principle of piezoelectric expansion, also known as the piezoelectric effect,
which is well
known to persons of ordinary skill in the art. Stator piezoelectric actuators
17 are constructed
so that their expansion is along their long axes: in other words, when the
stator piezoelectric
actuators are energized, the distance between magnet mount end 17b and hub end
17a
increases.
[00143] Mounted to magnet mount ends 17b are stator magnets 16, having
stator north
poles 16a and stator south poles 16b. Any suitable magnet may be used for
stator magnets 16,
including but not limited to rare-earth magnets, ferromagnets, and/or ceramic
magnets
containing ferromagnetic and/or rare- earth magnetic particles. Electromagnets
may also be
3021P-MBE-CAD1 28
Date Recue/Date Received 2022-02-28
used. If electromagnets are used, it is optional, but neither preferred nor
required, to allow them
to reverse polarity as driven by a solid-state commutator of the type found in
traditional
brushless electric motors.
[00144] It is strongly preferred that the rotor magnets and the stator
magnets have the
same poles (north and north or south and south) in opposition at their closest
points (as shown)
but with proper configuration, it is possible to practice the invention with
the rotor magnets
and the stator magnets having opposite poles (north and south or south and
north) in opposition.
If opposite poles are put into opposition, the motor may require an external
initiating force
and/or the stator piezoelectric actuators may be required to be energized in a
staggered
sequence. If reversible electromagnets are used for either the rotor magnets,
the stator magnets,
or both, the question of initial polarities is unimportant.
[00145] The preferred embodiment pictured in FIGURE 1 shows the
invention ready to
be practiced. The magnetic forces from the rotor magnets and the stator
magnets are at a point
of equilibrium where the magnets are in the lowest possible potential energy
state with regard
to the magnetic repulsion between the rotor magnets and the stator magnets.
Inner rotor element
14 will, absent the addition of energy from some exterior source, remain at
this point of
equilibrium indefinitely.
[00146] To practice this aspect of the disclosure, when a torque of
some sort is imposed
on the rotor assembly, the rotor may rotate, but the rotor magnets and the
stator magnets will
.. continue to repel each other, and a controlled, friction free rotation is
provided by the bearing.
It should be noted that the components in FIGURE 1 are greatly simplified:
while the bearing
as shown in FIGURE 1 would function, in practice the magnetic bearing would
have far fewer
gaps between the individual rotor magnets and the individual stator magnets
(see e.g. FIGURE
6.)
[00147] When additional control or torque ¨ either in the same direction of
current
rotation or opposed to the current rotation ¨ is required, stator
piezoelectric actuators 17 are
energized. This causes the distance between hub end 17b and magnet mount end
17a to
increase, pushing stator magnet 16 closer to rotor magnet 15. This increases
the magnetic
repulsion between the rotor magnet and the stator magnet, disturbing the
equilibrium between
them.
3021P-MBE-CAD1 29
Date Recue/Date Received 2022-02-28
[00148] The switching power supply is controlled by a frequency
controller (not shown)
which causes it to energize and de-energize stator piezoelectric actuators 17
at a frequency
which maintains optimal rotational characteristics for the magnetic bearing.
Additional sensors
can be linked to the frequency controller to enable such control. For
instance, and without
limiting the possible control means and methods:
[00149] If transient accelerations are detected, the frequency
controller could energize
those piezoelectric actuators on the appropriate side of the bearing to push
the rotor back into
a more centralized orientation, resisting the transient diametric
accelerations; and/or
[00150] If excessive heat is detected, the frequency controller could
de- energize the
piezoelectric actuators to increase the overall gap between the stator magnets
and the rotor
magnets, allowing more air to flow through the gap and provide additional
cooling; and/or
[00151] If the stator or rotor elements are detected to have expanded
or contracted due
to thermal changes, the frequency controller could energize or de-energize the
piezoelectric
actuators as needed to maintain a target gap between the rotor magnets and the
stator magnets.
[00152] As is apparent, if desired the frequency controller can energize
and de-energize
the piezoelectric actuators in ways which can convert magnetic potential
energy into rotational
energy and accelerate or decelerate inner rotor element 14 in a rotational
fashion. It is preferred,
but not required, that sensors (not shown) be operably connected to the inner
rotor element or
otherwise be able to detect its angular velocity, and communicate it to the
frequency controller
such that the frequency controller can adjust the driving frequency to
increase or decrease the
force exerted by the stator magnets on the rotor magnets and thus either
increase the speed of
rotation (under constant load,) increase the applied torque (under increasing
load,) or both.
[00153] If such sensors are used, the invention can also be used as an
extremely precise
stepper motor and/or rotational position sensor. It is preferred, but not
required, that a sensor
allowing absolute rotational position data also be incorporated into the
invention if such a usage
is desired. This allows the frequency controller to know where the inner rotor
element is at the
beginning and the end of a step cycle.
[00154] Once the equilibrium between the rotor magnets and the stator
magnets is
disturbed, the system will have more magnetic potential energy than before,
which will cause
3021P-MBE-CAD1 30
Date Recue/Date Received 2022-02-28
the rotor magnets to exert a force on inner rotor 14. Inner rotor element 14
is free to rotate, so
it will rotate in one direction or the other as impelled by the balance of
forces. As will be shown
in later figures, control of the shape and orientation of the rotor magnets
and/or stator magnets
will allow for a preferred direction of rotation.
[00155] Although the preferred embodiment is described as a magnetic
bearing, which
is designed to provide a highly controllable magnetic bearing between a load
and a fixed base,
it will be apparent to persons of ordinary skill in the art that since the
piezoelectric effect works
both ways ¨ electrical potential can be turned into mechanical force, and
mechanical force can
be turned into electrical potential ¨ that the preferred embodiment can also
serve as a generator
of electrical power if an external load forces the inner rotor element to
rotate against the
magnetic force attempting to hold it in equilibrium. Similarly, the preferred
embodiment can
also be used as a drive motor which also provides regenerative braking by
switching from
power in (during drive mode) to power out (during regenerative braking mode.)
All of the
alternate configurations/embodiments/methods of practice described in this
paragraph are
applicable to all of the embodiments of the invention disclosed in this
application.
[00156] FIGURE 2 shows a first alternate embodiment of the magnetic
bearing. The
first alternate embodiment of the magnetic bearing works in the same general
fashion as the
embodiment of FIGURE 1, except where noted otherwise. It likewise would
incorporate a
switching power supply, frequency controller, and could incorporate sensors,
et cetera.
[00157] Magnetic bearing 20 incorporates rotor piezoelectric actuators 27b,
analogous
to stator piezoelectric actuators 17 in FIGURE 1. Magnetic bearing 20 also
incorporates stator
piezoelectric actuators 27a. It is neither preferred nor required for either
configuration to be
applied with a single (inner and outer) group of piezoelectric actuators or a
double (inner and
outer) group of piezoelectric actuators: the two configurations are shown for
clarity of
disclosure.
[00158] When either stator piezoelectric actuators 27a or rotor
piezoelectric actuators
27b are energized, rotor magnets 25 are pushed toward stator magnets 26, and
as in FIGURE
1, magnetic repulsion is increased, incurring a force against the rotor
piezoelectric actuators.
As the rotor piezoelectric actuators are affixed to outer casing 21, which is
free to rotate relative
to hub 29 on optional mechanical bearing 52 (not identified, see FIGURE 5)
which includes
3021P-MBE-CAD1 31
Date Recue/Date Received 2022-02-28
race 22 containing balls 23, balls 23 bearing the load and allowing rotation
of rotary center
bearing element 24 relative to fixed center bearing element 28.
[00159] As with the previous embodiment, the elements of mechanical
bearing 52 are
optional. They are not required, and the magnetic bearing will function
without them. They
could also serve as a secondary bearing if for whatever reason it was desired
that the hub
elements could rotate independenly of the rotor elements. It is optional, if
such a mechanical
bearing is incorporated into the invention, to add mechanical or electrical
features that allow it
to only rotate in one direction. This would create a mechanical lock between
the rotor elements
and the hub elements such that the rotor could drive the hub if the rotor is
rotating in the same
direction as the hub, but if the magnetic bearing fails in such a way as to
prevent the magnetic
bearing from rotating, the hub elements would be free to rotate and come to a
controlled stop,
minimizing damage to the magnetic bearing assembly.
[00160] Depending on the desired method of operation, the stator
piezoelectric actuators
can be activated in concert with the rotor piezoelectric actuators, or only
one or the other group
of piezoelectric actuators can be active at any given time. If using the
magnetic bearing to
accelerate or decelerate the load, activating both at once can be used to
increase
torque/rotational velocity, whereas activating only one or the other can be
used for lower output
modes. Alternatively, one group of piezoelectric actuators can be wired to
deliver input power
(motor driving) and the other group wired to receive output power
(generation/regenerative
braking.) The groups of piezoelectric actuators can also be wired such that
some of the
actuators in each group are preferentially used to deliver input power and
some are
preferentially used to receive output power. Finally, all or fewer than all of
the piezoelectric
actuators in a particular group can be active at any given time to deliver any
particular desired
amount of input power or receive any particular desired amount of output
power, allowing an
additional means of controlling power flow and/or reducing electrical fatigue
on the individual
components as they are cycled in and out of service.
[00161] FIGURE 3 shows the first alternate embodiment in cutaway form.
Magnetic
bearing 20, having the same components as in FIGURE 2, is surrounded by
backing plate 33
and housing 31, while hollow shaft 32, which is operably affixed to hub 29
(see FIGURE 2)
and/or rotary center bearing element 24, allows either delivery of mechanical
rotational energy
3021P-MBE-CAD1 32
Date Recue/Date Received 2022-02-28
(motor mode) or input of mechanical rotational energy (generation/regenerative
braking
mode.)
[00162] FIGURE 4 shows a pair of opposing piezoelectric actuators and
their
corresponding magnets in detail. Stator piezoelectric actuator 27b is affixed
to stator magnet
.. 25 which has stator north pole 25a and stator south pole 25b. Rotor
piezoelectric actuator 27a
is affixed to rotor magnet 26 which has rotor north pole 26a and rotor south
pole 27a. It is
preferred, but not required, that the rotor magnets and the stator magnets be
asymmetrical to
each other (that is, the rotor magnets are not symmetrical with the stator
magnets, shown here
as their being different sizes) to make it easier to overcome the tendency of
the system to "lock"
into a position of minimized magnetic potential energy. Since the magnets are
not symmetrical,
when they are moved in relation to each other the corresponding magnetic
fields will tend to
push more in one direction than the other, overcoming such locking symmetry.
[00163] FIGURE 5 shows a more complete assembly of the first alternate
embodiment
of the invention for clarity of disclosure. Axial bolt 51 holds the assembly
together and keeps
the rotary elements on-center. Bearing 52 incorporates rotary center bearing
element 24, race
22, balls 23, and fixed center bearing element 28. (See FIGURE 2 for more
detail.)
[00164] FIGURE 6 shows a second alternate embodiment of the magnetic
bearing with
a more complex configuration of rotor magnets and stator magnets. This
configuration, while
not required, is somewhat preferred as it provides multiple benefits to the
practice of the
invention at the price of higher complexity and cost of manufacture.
[00165] Magnetic bearing 60 comprises rotor assembly 614 and stator
assembly 618.
Rotably affixing the rotor assembly to the stator assembly is bearing 652
which rotates around
central point 611. Mechanically affixed to bearing 652 are one or more stator
piezoelectric
elements.
[00166] As with the previously described embodiments, the elements of
mechanical
bearing 652 are optional. They are not required, and the magnetic bearing will
function without
them.
[00167] Shown is a configuration with six such stator piezoelectric
elements including
stator piezoelectric element 619. Mechanically affixed to the stator
piezoelectric elements are
3021P-MBE-CAD1 33
Date Recue/Date Received 2022-02-28
stator magnet elements such as stator magnet element 640. The stator magnet
elements
comprise one or more magnets having a north pole and a south pole, such as
stator magnet 617
having stator magnet north pole 617a and stator magnet south pole 617b. There
is a gap
between the stator magnet elements and one or more rotor magnet elements.
Shown is a
configuration with six such rotor magnet elements including rotor magnet
element 642. Each
rotor magnet element includes one or more rotor magnets such as rotor magnet
616, which has
rotor magnet north pole 616a and rotor magnet south pole 616b.
[00168] It is not required that each rotor magnet element be exactly
geometrically
opposed to a stator magnet element at any particular time during operation or
non-operation
and in fact it is likely that the equilibrium during non-operation will result
in some degree of
offset. It is strongly preferred that there be a rotor magnet element for each
stator magnet
element, and vice versa. It is required that there be a gap between the rotor
magnet elements
and the stator magnet elements sufficient to allow the rotor magnet elements
to move freely
without contacting the stator magnet elements under any reasonable amount of
bearing load,
rotary speed, or transient vibratory load.
[00169] Although the configuration of magnets shown will be inherently
stable due to
magnetic attraction between the individual magnets, it is preferred that the
magnets in each
rotor magnet element and stator magnet element be epoxied or otherwise
physically affixed to
each other to maintain the desired alignment and prevent shifting under load
or due to vibration
or other transient phenomena.
[00170] It is strongly preferred, but not required, to use an
overlapping configuration of
magnets as shown in the rotor magnet elements and the stator magnet elements
as this will
minimize asymmetries in the overall magnetic field structure in the brushless
magnetic motor.
[00171] FIGURE 7 shows a more complete assembly of the second alternate
embodiment of the invention for clarity of disclosure along with the addition
of an optional set
of stator piezoelectric actuators as in FIGURE 2. (See FIGURE 6 for more
detail.) Axial bolt
651 holds the assembly together and keeps the elements on-center. Capacitor
array bolts 680
affix capacitor array 656 to base element 682 by means of threaded receivers
681. Although
shown as traditional capacitive plates, any desired means of capacitive
induction of current,
such as vacuum-tube capacitors, can be used.
3021P-MBE-CAD1 34
Date Recue/Date Received 2022-02-28
[00172] For purposes of this description, it is assumed that base
element 682 is secured
to something which is designated as static and therefore base element 682
forms part of a stator
assembly. For example, if motor 60 were to be used to bear the load of the
wheel of an electric
vehicle, base element 682 would ultimately be statically affixed to the
chassis of the vehicle,
whereas housing 612 would ultimately be statically affixed to the wheel of the
vehicle.
[00173] Capacitor array 680, which does not rotate relative to the
stator assembly,
includes capacitor plates such as capacitor plate 658, each capacitor plate
separated by a gap
such as capacitor gaps 657a and 657b. Capacitor array energizes rotor
piezoelectric array 621,
which includes one or more rotor piezoelectric actuators such as rotor
piezoelectric actuator
621. The rotor piezoelectric actuators are mechanically affixed to one or more
(optional) rotor
magnet brackets 678, each rotor magnet bracket having a rotor circumferential
surface 662,
and (optional) rotor vertical guides 661a and 661b, with all of the rotor
magnet brackets
forming rotor magnet bracket assembly 660.
[00174] Mechanically affixed to the rotor piezoelectric actuators,
either directly or via
the (optional) rotor magnet brackets, are one or more rotor magnet elements
such as rotor
magnet element 642, each rotor magnet element comprising one or more rotor
magnets such
as rotor magnet 616, with all of the rotor magnet elements forming rotor
magnet assembly 672.
[00175] During active operation of the piezoelectric actuators, the
rotor piezoelectric
actuators are energized, causing them to expand toward the center of motor 60
(since they
cannot expand against the fixed position of the rest of the rotor assembly
including ultimately
housing 612) pushing the rotor magnet elements toward the stator magnet
elements (see below)
and imparting a magnetic force as explained in previous descriptions (see
FIGURES 1, 2, and
6.) The rotor piezoelectric actuators can be energized one at a time, all
together, or in sequence,
as is desired and appropriate for the load and conditions. The rotor
piezoelectric actuators can
be energized without energizing the stator piezoelectric actuators (see below)
or in concert with
them.
[00176] Rotor magnet assembly 672 radially surrounds stator magnet
assembly 670, the
rotor magnet assembly separated from the stator magnet assembly by a gap (NOT
SHOWN,
see FIGURE 9.) Stator magnet assembly 670 comprises one or more stator magnet
elements
such as stator magnet element 640, each stator magnet element comprising one
or more stator
3021P-MBE-CAD1 35
Date Recue/Date Received 2022-02-28
magnets such as stator magnet 617. Stator magnet elements are mechanically
affixed to stator
piezoelectric assembly 669, which includes one or more stator piezoelectric
actuators such as
stator piezoelectric actuator 619, either directly or by means of (optional)
stator magnet bracket
assembly 655. (Optional) stator magnet bracket assembly 655 comprises one or
more stator
magnet brackets such as stator magnet bracket 676, each stator magnet bracket
including a
stator circumferential surface such as stator circumferential surface 654 and
(optional) stator
vertical guides 653a and 653b.
[00177] When energized, the stator piezoelectric actuators expand
toward the outer
circumference of motor 60 (since they cannot expand toward the fixed position
of the rest of
the stator assembly) pushing the stator magnet elements toward the rotor
magnet elements and
imparting a magnetic force as explained in previous descriptions (see FIGURES
1, 2, and 6.)
This ultimately causes the rotor assembly, including housing 612, to rotate,
allowing for rotary
force to be exerted through hollow shaft 632. The stator piezoelectric
actuators can be
energized one at a time, all together, or in sequence, as is desired and
appropriate for the load
and conditions. The stator piezoelectric actuators can be energized without
energizing the rotor
piezoelectric actuators or in concert with them.
[00178] FIGURE 8 shows the configuration of FIGURE 7 in an alternate
phase of
assembly for clarity of disclosure. Housing 612 is ready to be placed over the
rest of the motor
assembly, with capacitor array 656 ready to be secured to base element 682
with capacitor
array bolts 680. The rotor and stator elements are assembled, for example
rotor piezoelectric
actuator affixed to rotor circumferential surface 662 and stator piezoelectric
actuator affixed to
stator circumferential surface 654, and both ready to be inserted into their
respective
assemblies.
[00179] FIGURE 9 shows the configuration of FIGURE 7 in a cutaway view
for clarity
of disclosure. Housing 612 is axially secured by axial bolt 651 but is free to
rotate relative to
base element 682 as they are mechanically connected only by bearings 652 and
683. Rotor
magnet element 642 is separated from stator magnet element 640 by gap 690. The
size of gap
690 can be changed by energizing stator piezoelectric actuator 619 and/or
rotor piezoelectric
actuator 621. As the piezoelectric actuators change the size of gap 690, the
relative orientation
of the magnetic fields of the rotor magnet elements and the stator magnet
elements will change.
This will cause magnetic force to be exerted between magnet elements, but as
only the rotor
3021P-MBE-CAD1 36
Date Recue/Date Received 2022-02-28
magnet elements (ultimately connected to housing 612) can move, the force will
cause housing
612 to move, allowing rotary motion to be imparted to hollow shaft 632 and
thus to an axle, a
wheel, or any other rotary member or rotary load desired.
[00180] FIGURE 10 shows a third alternate embodiment of this aspect of
the invention.
In this embodiment, rather than a plurality of distinctive magnets, the rotor
magnets comprise
a single piece of rotor magnetic material, which is structured to have a
plurality of magnetic
regions, each magnetic region having a north pole and a south pole. Similarly,
there are two
individual pieces of stator magnetic material having a plurality of magnetic
regions. Each piece
of stator magnetic material is attached to one end of a single piezoelectric
actuator.
[00181] Magnetic bearing 80 comprises rotor assembly 82, stator magnet
assemblies 84
and 87, and piezoelectric actuator 810 which is operably affixed to PCB 92
(NOT SHOWN:
See FIGURE 11.) Rotor assembly 82, which is free to rotate relative to all
stator assembly
components and is attached to whatever rotational load (NOT SHOWN) it is
desired to bear
with the bearing, is comprised of magnetic material (or can have an inner
section of magnetic
material surrounded by non-magnetic material as desired) which has magnetic
regions, each
magnetic region having a north pole and a south pole such as rotor north poles
82a and 82b and
rotor south poles 83a and 83b. Opposite the rotor assembly's magnetic
material, separated by
a gap (See FIGURE 11) are stator magnet assemblies 84 and 87. It is possible
to construct this
embodiment of the invention with a single stator magnet assembly, but it is
strongly preferred
to use two symmetrical stator magnet assemblies as shown for purposes of
balance and to
maximize the piezoelectric actuator's efficiency. First stator magnet assembly
84, similarly to
rotor section 82, is composed in whole or in part of magnetic material, which
has multiple
magnetic regions, each magnetic region having a north pole such as stator
north poles 85a and
85b and rotor south poles 86a and 86b. Second stator magnet assembly 87, is
likewise
composed in whole or in part of magnetic material, which has multiple magnetic
regions, each
magnetic region having a north pole such as stator north poles 85a and 85b and
stator south
poles 86a and 86b.
[00182] FIGURE 11 shows a cutaway view of the third alternate
embodiment of this
aspect of the invention for additional clarity of disclosure. Magnetic bearing
80 has gap 91,
which separates the various stator and rotor assemblies (see FIGURE 10) and
allows the
magnetic bearing to serve as a no-contact magnetic bearing so long as the
planar load does not
3021P-MBE-CAD1 37
Date Recue/Date Received 2022-02-28
materially affect the gap as maintained by the magnet assembly and the stator
magnet
assemblies. This is an additional advantage of several of the embodiments and
configurations
of the invention disclosed herein. PCB 92 is a printed circuit board which is
both mechanically
and electrically affixed to piezoelectric actuator 810 and provides it with
electrical potential
from a switching power supply (NOT SHOWN).
[00183] If necessary, fluid can be forcibly circulated around the
assemblies or even
through the gap to cool the motor, but as many piezoelectric devices actually
work better when
they reach a relatively high operating temperature, the need for cooling will
be minimal in
many applications. This is another advantage of the invention. It is required
that for all
embodiments and configurations of the invention, that operating temperatures
be kept low
enough to avoid demagnetization of any permanent magnets which are used. This
will vary as
various kinds of magnetic material have different demagnetization thresholds.
(For example,
some ferrite magnets can tolerate temperatures up to 250 C, whereas some rare-
earth magnets
can only tolerate temperatures up to 100 C.)
[00184] To practice an embodiment of this aspect of the invention, an
electrical potential
is put across piezoelectric actuator 810, which is electrically connected to
PCB 92. This causes
piezoelectric actuator 810 to expand along its long axis, changing the
relative position of the
stator magnet assemblies and the rotor assembly. This in turn causes
electromagnetic force to
be exerted on the rotor assembly, which will rotate to a position which will
minimize the
magnetic potential energy between the rotor assembly and the stator
assemblies. The electrical
potential across piezoelectric actuator 810, is then removed and/or reversed,
causing it to
contract along its long axis, again changing the relative position of the
various magnet
assemblies. A switching power supply (NOT SHOWN) continuously cycles the
electrical
potential across the piezoelectric actuator to produce the desired magnetic
bearing load and/or
acceleration or deceleration as in previously described embodiments.
[00185] It is optional, but neither preferred nor required, for either
the rotor assembly or
the stator assembly, or both, to comprise multiple magnets as in earlier
described
configurations. (See FIGURE 1, FIGURE 2, and/or FIGURE 6.) So long as the
rotor assembly
and the stator assembly are configured as shown, the configuration of this
third alternate
embodiment incorporating a single piezoelectric actuator will function and
provide the benefits
of the invention.
3021P-MBE-CAD1 38
Date Recue/Date Received 2022-02-28
[00186] Alternate configurations of this aspect of the disclosure,
which can be applied
to any of the described embodiments, will now be disclosed.
[00187] In a first alternate configuration of this aspect (NOT SHOWN)
some or all of
the rotor magnets, or some or all of the stator magnets, of either the
preferred embodiment or
the first alternate embodiment are replaced with electromagnets.
[00188] In a second alternate configuration of this aspect (NOT SHOWN)
one or more
elastic members is fitted into the motor assembly such that the piezoelectric
actuators are
working against the elastic members when they are energized, compressing them
and creating
elastic potential energy, so that when the piezoelectric actuator(s) is/are de-
energized, the
magnet(s) affixed to the piezoelectric actuator(s) return to their prior
position more quickly and
without the need to impose a reverse polarity potential across the
piezoelectric actuator when
the elastic potential energy provides impetus to the piezoelectric actuators.
[00189] In a third alternate configuration of this aspect (NOT SHOWN),
the features of
the first and second configurations are combined.
[00190] It will be apparent to those of ordinary skill in the art that
while the invention
and its preferred embodiments are described in terms of rotary bearings, the
principles taught
by the invention can be used to create linear bearings, such as reciprocating
bearings, by using
the basic principle of piezoelectric motivation of opposing magnetic elements
to create a
magnetic repulsion along a linear bearing interface instead of a rotary
bearing interface. Thus,
.. the claims below include both rotary configurations and linear
configurations where and as
appropriate.
ELECTRIC STEPPER MOTOR
[00191] In acccordance with another aspect of the disclosure, an
electric stepper motor
10 will now be described.
[00192] For purposes of this aspect of the disclosure, piezoelectric
actuators are
described as being "electrically connected" to a switching power supply. Such
a connection
can be made via physical conductors (wires, PCB conductive paths, conductive
inks, et cetera)
or by any other reasonable means that allows the switching power supply to
supply energy to
the piezoelectric actuators and causes the piezoelectric effect to change the
dimensions of the
3021P-MBE-CAD1 39
Date Recue/Date Received 2022-02-28
piezoelectric actuators. This includes, but is not limited to, electromagnetic
induction or
transfer by capacitance. It is required that the means of electrical
connection be able to switch
the piezoelectric actuators on and off and/or apply a current flow in one
direction and then in
the other direction fast enough to allow the motor to operate, as will be made
clear in the
specification below. This will be referred to generally as "rise" time ¨ the
period of time it
takes to energize the piezoelectric actuator and/or the capacitator powering
it ¨ and the "fall"
time ¨ the period of time it takes to deenergize the piezoelectric actuator
and/or the capacitor
powering it.
[00193] For purposes of this aspect of the disclosure, motors will
generally have a group
of components which remains static relative to a load, and a second group of
components which
will move relative to the first group of components. The first group of
components will be
referred to collectively as a stator assembly, and the second group referred
to collectively as a
rotor assembly. Prefixing a component with the word "rotor" or "stator"
indicates which group
of components it belongs to in the embodiment/configuration which is currently
being
described. Piezoelectric actuators in the stator assembly are stator
piezoelectric actuators (or
simply stator actuators) and magnets affixed to stator piezoelectric actuators
are stator magnets,
and vice versa with regard to the rotor assembly.
[00194] At the same time, for purposes of this aspect of the
disclosure, magnets can also
be described as falling into one or both of two distinct types independent of
whether they are
part of the stator assembly or the rotor assembly. Actuator magnets are
magnets which have/are
having force imposed upon them by a piezoelectric actuator. Response magnets
are magnets
which have/are having force imposed upon them via magnetic field interactions
with actuator
magnets. If only one group of magnets is affixed to piezoelectric actuators,
those are the
actuator magnets, and the rest of the magnets in the motor are response
magnets. If multiple
groups of magnets are affixed to piezoelectric actuators, magnets affixed to a
piezoelectric
actuator which is being energized and causing it to impose force on those
magnets are actuator
magnets, and magnets which are not so affixed, or which are affixed to a
piezoelectric actuator
which is not being energized, are response magnets. It is possible for any
given magnet to be
an actuator magnet or a response magnet or both at any given time depending on
the motor
controller's configuration and energization of the piezoelectric actuators. A
rotor magnet or a
stator magnet may at any time be an actuator magnet, a response magnet, or
both.
3021P-MBE-CAD1 40
Date Recue/Date Received 2022-02-28
[00195] By referring to FIGURE 12, the basic nature of this aspect of
the disclosure can
be easily understood. Outer rotor housing 11 surrounds bearing 12 which is
free to rotate on
balls 13, which bear the load between the motor and whatever it is mounted in
and whatever it
is driving. Inner rotor element 14 has multiple rotor magnets 15 having rotor
north poles 15a
and rotor south poles 15b. Any suitable magnet may be used for rotor magnets
15, including
but not limited to rare-earth magnets, ferromagnets, and/or ceramic magnets
containing
ferromagnetic and/or rare- earth magnetic particles. Electromagnets may also
be used. If
electromagnets are used, it is optional, but neither preferred nor required,
to allow them to
reverse polarity as driven by a solid-state commutator of the type found in
traditional brushless
electric motors.
[00196] Stator assembly 19 consists of central hub 18, which supports
multiple stator
piezoelectric actuators 17. Stator piezoelectric actuators 17 have a magnet
mount end 17a and
a hub end 17b. Stator piezoelectric actuators 17 are connected to a switching
power supply (not
shown) which can energize the stator piezoelectric actuators at any reasonable
driving
frequency. When the stator piezoelectric actuators are energized, they expand,
using the
principle of piezoelectric expansion, also known as the piezoelectric effect,
which is well
known to persons of ordinary skill in the art. Stator piezoelectric actuators
17 are constructed
so that their expansion is along their long axes: in other words, when the
stator piezoelectric
actuators are energized, the distance between magnet mount end 17b and hub end
17a
increases.
[00197] Mounted to magnet mount ends 17b are stator magnets 16, having
stator north
poles 16a and stator south poles 16b. Any suitable magnet may be used for
stator magnets 16,
including but not limited to rare-earth magnets, ferromagnets, and/or ceramic
magnets
containing ferromagnetic and/or rare- earth magnetic particles. Electromagnets
may also be
used. If electromagnets are used, it is optional, but neither preferred nor
required, to allow them
to reverse polarity as driven by a solid-state commutator of the type found in
traditional
brushless electric motors.
[00198] It is strongly preferred that the rotor magnets and the stator
magnets have the
same poles (north and north or south and south) in opposition at their closest
points (as shown)
but with proper configuration, it is possible to practice the invention with
the rotor magnets
and the stator magnets having opposite poles (north and south or south and
north) in opposition.
3021P-MBE-CAD1 41
Date Recue/Date Received 2022-02-28
If opposite poles are put into opposition, the motor may require an external
initiating force
and/or the stator piezoelectric actuators may be required to be energized in a
staggered
sequence. If reversible electromagnets are used for either the rotor magnets,
the stator magnets,
or both, the question of initial polarities is unimportant.
[00199] The preferred embodiment pictured in FIGURE 12 shows the invention
ready
to be practiced. The magnetic forces from the rotor magnets and the stator
magnets are at a
point of equilibrium where the magnets are in the lowest possible potential
energy state with
regard to the magnetic repulsion between the rotor magnets and the stator
magnets. Inner rotor
element 14 will, absent the addition of energy from some exterior source,
remain at this point
of equilibrium indefinitely.
[00200] To practice the invention, stator piezoelectric actuators 17
are energized. This
causes the distance between hub end 17b and magnet mount end 17a to increase,
pushing stator
magnet 16 closer to rotor magnet 15. This increases the magnetic repulsion
between the rotor
magnet and the stator magnet, disturbing the equilibrium between them. In the
configuration
shown, it may be necessary to impart a slight initial rotational force and/or
to energize the stator
piezoelectric actuators in sequence so as to asymmetrically disturb the
equilibrium of magnetic
forces and allow rotation to begin.
[00201] Once the equilibrium between the rotor magnets and the stator
magnets is
disturbed, the system will have more magnetic potential energy than before,
which will cause
the rotor magnets to exert a force on inner rotor 14. Inner rotor element 14
is free to rotate, so
it will rotate in one direction or the other as impelled by the balance of
forces. As will be shown
in later figures, control of the shape and orientation of the rotor magnets
and/or stator magnets
will allow for a preferred direction of rotation.
[00202] The switching power supply is controlled by a frequency
controller (not shown)
which causes it to energize and de-energize stator piezoelectric actuators 17
at a frequency
which will continue to convert magnetic potential energy into rotational
energy and accelerate
inner rotor element 14 in a rotational fashion. It is preferred, but not
required, that sensors (not
shown) be operably connected to the inner rotor element or otherwise be able
to detect its
angular velocity, and communicate it to the frequency controller such that the
frequency
controller can adjust the driving frequency to increase or decrease the force
exerted by the
3021P-MBE-CAD1 42
Date Recue/Date Received 2022-02-28
stator magnets on the rotor magnets and thus either increase the speed of
rotation (under
constant load,) increase the applied torque (under increasing load,) or both.
[00203] If
such sensors are used, the utility of the invention as a precise stepper motor
is further increased. It is preferred, but not required, that a sensor
allowing absolute rotational
position data also be incorporated into the invention if such a usage is
desired. This allows the
frequency controller to know where the inner rotor element is at the beginning
and the end of
a step cycle.
[00204]
With or without the sensors, the switching power supply energizes and de-
energizes the stator piezoelectric actuators, with each energization/de-
energization cycle
imparting a fixed amount of energy into the rotation of the motor. Since the
geometry of the
stator magnets and the rotor magnets is known, in its simplest embodiment, the
invention can
be practiced as a stepper motor simply by sending a single energization/de-
energization pulse
to the stator piezoelectric actuators. This will cause the motor assembly to
rotate through the
arc-section occupied by a single set of opposing rotor/stator magnets. Once
the stator
piezoelectric actuators are de-energized, magnetic repulsion between the rotor
magnets and the
stator magnets will cause the rotation of the rotor to stop as the rotor
magnets will not want to
move "past" the stator magnets absent the impulse provided by the stator
piezoelectric
actuators. To get additional fractional rotations, additional energization/de-
energization pulses
can be sent, which will each produce an additional single rotation through
such arc-section.
[00205] If the rotor and the external load on the rotor have too much
inertia for the rotor
and stator magnets to stop the rotor after the energization/de- energization
cycles stop by simple
magnetic repulsion, multiple methods of further precisely controlling the
rotation of the electric
stepper motor may be applied, including but not limited to:
1) It
is preferred to use the stator piezoelectric actuators to apply a braking
force to the
rotor. The frequency controller can be used to cause the stator piezoelectric
actuators to push
the stator magnets toward the rotor magnets at the point in their rotation
where it would tend
to slow the rotation of the rotor, not accelerate it. As modern frequency
controllers and
switching power supplies are capable of very fast and very precise control of
electrical circuits,
this can provide very precise control of the acceleration/braking of the
electric stepper motor.
3021P-MBE-CAD1 43
Date Recue/Date Received 2022-02-28
2) An
external brake (not shown) of some kind can be engaged whenever the stepper
motor is not desired to be moving, such that as soon as the stator
piezoelectric actuators are not
being energized, sufficient friction to stop the rotation of the rotor (and
the external load) is
applied.
[00206] Although the preferred embodiment is described as an electric
stepper motor,
which is designed to convert electrical potential from a switching power
supply into rotational
energy, it will be apparent to persons of ordinary skill in the art that since
the piezoelectric
effect works both ways ¨ electrical potential can be turned into mechanical
force, and
mechanical force can be turned into electrical potential ¨ that the preferred
embodiment can
also serve as a generator of electrical power if an external load forces the
inner rotor element
to rotate against the magnetic force attempting to hold it in equilibrium.
[00207]
Similarly, the preferred embodiment can also be used as a drive motor which
also provides regenerative braking by switching from power in (during drive
mode) to power
out (during regenerative braking mode.) All of the alternate
configurations/embodiments/methods of practice described in this paragraph are
applicable to
all of the embodiments of the invention disclosed in this application.
[00208]
Additional embodiments of the electric stepper motor will now be described.
All of the additional embodiments are alternate configurations of the physical
motor itself: the
principles by which each embodiment can be used as an electric stepper motor
is identical to
that described above.
[00209]
FIGURE 13 shows a first alternate embodiment of the electric stepper motor.
The first alternate embodiment of the electric stepper motor works in the same
general fashion
as the embodiment of FIGURE 12, except where noted otherwise. It likewise
would
incorporate a switching power supply, frequency controller, and could
incorporate sensors, et
cetera.
[00210]
Electric stepper motor 20 incorporates rotor piezoelectric actuators 27b,
analogous to stator piezoelectric actuators 17 in FIGURE 12. Electric stepper
motor 20 also
incorporates stator piezoelectric actuators 27a. It is neither preferred nor
required for either
configuration to be applied with a single (inner and outer) group of
piezoelectric actuators or a
3021P-MBE-CAD1 44
Date Recue/Date Received 2022-02-28
double (inner and outer) group of piezoelectric actuators: the two
configurations are shown for
clarity of disclosure.
[00211] When either stator piezoelectric actuators 27a or rotor
piezoelectric actuators
27b are energized, rotor magnets 25 are pushed toward stator magnets 26, and
as in FIGURE
.. 12, magnetic repulsion is increased, incurring a force against the rotor
piezoelectric actuators.
As the rotor piezoelectric actuators are affixed to outer casing 21, which is
free to rotate relative
to hub 29 on bearing 52 (not identified, see FIGURE 16) which includes race 22
containing
balls 23, balls 23 bearing the load and allowing rotation of rotary center
bearing element 24
relative to fixed center bearing element 28.
[00212] Depending on the desired method of operation, the stator
piezoelectric actuators
can be activated in concert with the rotor piezoelectric actuators, or only
one or the other group
of piezoelectric actuators can be active at any given time. Activating both at
once can be used
to increase torque/rotational velocity, whereas activating only one or the
other can be used for
lower output modes. Alternatively, one group of piezoelectric actuators can be
wired to deliver
input power (motor driving) and the other group wired to receive output power
(generation/regenerative braking.) The groups of piezoelectric actuators can
also be wired such
that some of the actuators in each group are preferentially used to deliver
input power and some
are preferentially used to receive output power. Finally, all or fewer than
all of the piezoelectric
actuators in a particular group can be active at any given time to deliver any
particular desired
amount of input power or receive any particular desired amount of output
power, allowing an
additional means of controlling power flow and/or reducing electrical fatigue
on the individual
components as they are cycled in and out of service.
[00213] FIGURE 14 shows the first alternate embodiment in cutaway form.
Electric
stepper motor 20, having the same components as in FIGURE 13, is surrounded by
backing
plate 33 and housing 31, while hollow shaft 32, which is operably affixed to
hub 29 (see
FIGURE 13) and/or rotary center bearing element 24, allows either delivery of
mechanical
rotational energy (motor mode) or input of mechanical rotational energy
(generation/regenerative braking mode.)
[00214] FIGURE 15 shows a pair of opposing piezoelectric actuators and
their
corresponding magnets in detail. Stator piezoelectric actuator 27b is affixed
to stator magnet
3021P-MBE-CAD1 45
Date Recue/Date Received 2022-02-28
25 which has stator north pole 25a and stator south pole 25b. Rotor
piezoelectric actuator 27a
is affixed to rotor magnet 26 which has rotor north pole 26a and rotor south
pole 27a. It is
preferred, but not required, that the rotor magnets and the stator magnets be
asymmetrical to
each other (that is, the rotor magnets are not symmetrical with the stator
magnets, shown here
as their being different sizes) to make it easier to overcome the tendency of
the system to "lock"
into a position of minimized magnetic potential energy. Since the magnets are
not symmetrical,
when they are moved in relation to each other the corresponding magnetic
fields will tend to
push more in one direction than the other, overcoming such locking symmetry.
However, if it
is desired to mainly use pure magnetic repulsion as a braking force for steps
of the stepper
motor, it may be preferred to make the magnets as symmetrical as possible so
as to maximize
the efficiency of the individual attraction/repulsion of the individual rotor
magnet/stator
magnet pairs.
[00215] FIGURE 16 shows a more complete assembly of the first alternate
embodiment
of the invention for clarity of disclosure. Axial bolt 51 holds the assembly
together and keeps
the rotary elements on-center. Bearing 52 incorporates rotary center bearing
element 24, race
22, balls 23, and fixed center bearing element 28. (See FIGURE 13 for more
detail.)
[00216] FIGURE 17 shows a second alternate embodiment of the electric
stepper motor
with a more complex configuration of rotor magnets and stator magnets. This
configuration,
while not required, is somewhat preferred as it provides multiple benefits to
the practice of the
invention at the price of higher complexity and cost of manufacture.
[00217] Electric stepper motor 60 comprises rotor assembly 614 and
stator assembly
618. Rotably affixing the rotor assembly to the stator assembly is bearing 652
which rotates
around central point 611. Mechanically affixed to bearing 652 are one or more
stator
piezoelectric elements. Shown is a configuration with six such stator
piezoelectric elements
including stator piezoelectric element 619. Mechanically affixed to the stator
piezoelectric
elements are stator magnet elements such as stator magnet element 640. The
stator magnet
elements comprise one or more magnets having a north pole and a south pole,
such as stator
magnet 617 having stator magnet north pole 617a and stator magnet south pole
617b. There is
a gap between the stator magnet elements and one or more rotor magnet
elements. Shown is a
configuration with six such rotor magnet elements including rotor magnet
element 642. Each
3021P-MBE-CAD1 46
Date Recue/Date Received 2022-02-28
rotor magnet element includes one or more rotor magnets such as rotor magnet
616, which has
rotor magnet north pole 616a and rotor magnet south pole 616b.
[00218] To practice this aspect of the invention, as with prior
described embodiments,
one or more of the stator piezoelectric actuators, such as stator
piezoelectric actuator 619, is
energized by a switching power supply (NOT SHOWN) controlled by a frequency
controller
(NOT SHOWN) such that when, for example, stator piezoelectric actuator 619 is
energized, it
expands along axis of expansion 619a, causing the corresponding stator magnet
element to get
closer to one or more rotor magnet elements. This produces a change in the
orientation of the
magnetic fields of the stator and rotor magnetic elements, causing the
corresponding stator
magnetic element to exert a force on the rotor magnetic element which in turn
causes the rotor
magnet element to exert a force on the housing 612, causing it, along with the
entire rotor
assembly 614 to rotate around central point 611 on bearing 652 relative to
stator assembly 618.
This rotational force is transmitted to an external load via hollow shaft 632
(NOT SHOWN,
see FIGURE 18.)
[00219] It is not required that each rotor magnet element be exactly
geometrically
opposed to a stator magnet element at any particular time during operation or
non-operation
and in fact it is likely that the equilibrium during non-operation will result
in some degree of
offset. It is strongly preferred that there be a rotor magnet element for each
stator magnet
element, and vice versa. It is required that there be a gap between the rotor
magnet elements
and the stator magnet elements sufficient to allow the rotor magnet elements
to move freely
without contacting the stator magnet elements under any reasonable amount of
bearing load,
rotary speed, or transient vibratory load.
[00220] Although the configuration of magnets shown will be inherently
stable due to
magnetic attraction between the individual magnets, it is preferred that the
magnets in each
rotor magnet element and stator magnet element be epoxied or otherwise
physically affixed to
each other to maintain the desired alignment and prevent shifting under load
or due to vibration
or other transient phenomena.
[00221] It is strongly preferred, but not required, to use an
overlapping configuration of
magnets as shown in the rotor magnet elements and the stator magnet elements
as this will
minimize asymmetries in the overall magnetic field structure in the brushless
magnetic motor.
3021P-MBE-CAD1 47
Date Recue/Date Received 2022-02-28
[00222] FIGURE 18 shows a more complete assembly of the second
alternate
embodiment of the invention for clarity of disclosure along with the addition
of an optional set
of stator piezoelectric actuators as in FIGURE 13. (See FIGURE 17 for more
detail.) Axial bolt
651 holds the assembly together and keeps the elements on-center. Capacitor
array bolts 680
affix capacitor array 656 to base element 682 by means of threaded receivers
681. Although
shown as traditional capacitive plates, any desired means of capacitive
induction of current,
such as vacuum-tube capacitors, can be used.
[00223] For purposes of this description, it is assumed that base
element 682 is secured
to something which is designated as static and therefore base element 682
forms part of a stator
assembly. For example, if motor 60 were to be used to drive a turntable, base
element 682
would ultimately be statically affixed to the base assembly of the turntable,
whereas housing
612 would ultimately be statically affixed to the turntable itself.
[00224] Capacitor array 680, which does not rotate relative to the
stator assembly,
includes capacitor plates such as capacitor plate 658, each capacitor plate
separated by a gap
such as capacitor gaps 657a and 657b. Capacitor array energizes rotor
piezoelectric array 621,
which includes one or more rotor piezoelectric actuators such as rotor
piezoelectric actuator
621. The rotor piezoelectric actuators are mechanically affixed to one or more
(optional) rotor
magnet brackets 678, each rotor magnet bracket having a rotor circumferential
surface 662,
and (optional) rotor vertical guides 661a and 661b, with all of the rotor
magnet brackets
forming rotor magnet bracket assembly 660. Mechanically affixed to the rotor
piezoelectric
actuators, either directly or via the (optional) rotor magnet brackets, are
one or more rotor
magnet elements such as rotor magnet element 642, each rotor magnet element
comprising one
or more rotor magnets such as rotor magnet 616, with all of the rotor magnet
elements forming
rotor magnet assembly 672.
[00225] When energized, the rotor piezoelectric actuators expand toward the
center of
motor 60 (since they cannot expand against the fixed position of the rest of
the rotor assembly
including ultimately housing 612) pushing the rotor magnet elements toward the
stator magnet
elements (see below) and imparting a magnetic force as explained in previous
descriptions (see
FIGURES 12, 13, and 17.) This ultimately causes the rotor assembly, including
housing 612,
to rotate, allowing for rotary force to be exerted through hollow shaft 632.
The rotor
piezoelectric actuators can be energized one at a time, all together, or in
sequence, as is desired
3021P-MBE-CAD1 48
Date Recue/Date Received 2022-02-28
and appropriate for the load and conditions. The rotor piezoelectric actuators
can be energized
without energizing the stator piezoelectric actuators (see below) or in
concert with them.
[00226] Rotor magnet assembly 672 radially surrounds stator magnet
assembly 670, the
rotor magnet assembly separated from the stator magnet assembly by a gap (NOT
SHOWN,
see FIGURE 20.) Stator magnet assembly 670 comprises one or more stator magnet
elements
such as stator magnet element 640, each stator magnet element comprising one
or more stator
magnets such as stator magnet 617. Stator magnet elements are mechanically
affixed to stator
piezoelectric assembly 669, which includes one or more stator piezoelectric
actuators such as
stator piezoelectric actuator 619, either directly or by means of (optional)
stator magnet bracket
assembly 655. (Optional) stator magnet bracket assembly 655 comprises one or
more stator
magnet brackets such as stator magnet bracket 676, each stator magnet bracket
including a
stator circumferential surface such as stator circumferential surface 654 and
(optional) stator
vertical guides 653a and 653b.
[00227] When energized, the stator piezoelectric actuators expand
toward the outer
circumference of motor 60 (since they cannot expand toward the fixed position
of the rest of
the stator assembly) pushing the stator magnet elements toward the rotor
magnet elements and
imparting a magnetic force as explained in previous descriptions (see FIGURES
12, 13, and
17.) This ultimately causes the rotor assembly, including housing 612, to
rotate, allowing for
rotary force to be exerted through hollow shaft 632. The stator piezoelectric
actuators can be
energized one at a time, all together, or in sequence, as is desired and
appropriate for the load
and conditions. The stator piezoelectric actuators can be energized without
energizing the rotor
piezoelectric actuators or in concert with them.
[00228] FIGURE 19 shows the configuration of FIGURE 18 in an alternate
phase of
assembly for clarity of disclosure. Housing 612 is ready to be placed over the
rest of the motor
assembly, with capacitor array 656 ready to be secured to base element 682
with capacitor
array bolts 680. The rotor and stator elements are assembled, for example
rotor piezoelectric
actuator affixed to rotor circumferential surface 662 and stator piezoelectric
actuator affixed to
stator circumferential surface 654, and both ready to be inserted into their
respective
assemblies.
3021P-MBE-CAD1 49
Date Recue/Date Received 2022-02-28
[00229] FIGURE 20 shows the configuration of FIGURE 18 in a cutaway
view for
clarity of disclosure. Housing 612 is axially secured by axial bolt 651 but is
free to rotate
relative to base element 682 as they are mechanically connected only by
bearings 652 and 683.
Rotor magnet element 642 is separated from stator magnet element 640 by gap
690. The size
of gap 690 can be changed by energizing stator piezoelectric actuator 619
and/or rotor
piezoelectric actuator 621. As the piezoelectric actuators change the size of
gap 690, the
relative orientation of the magnetic fields of the rotor magnet elements and
the stator magnet
elements will change. This will cause magnetic force to be exerted between
magnet elements,
but as only the rotor magnet elements (ultimately connected to housing 612)
can move, the
.. force will cause housing 612 to move, allowing rotary motion to be imparted
to hollow shaft
632 and thus to an axle, a wheel, or any other rotary member or rotary load
desired.
[00230] FIGURE 21 shows a third alternate embodiment of the invention.
In this
embodiment, rather than a plurality of distinctive magnets, the rotor magnets
comprise a single
piece of rotor magnetic material, which is structured to have a plurality of
magnetic regions,
each magnetic region having a north pole and a south pole. Similarly, there
are two individual
pieces of stator magnetic material having a plurality of magnetic regions.
Each piece of stator
magnetic material is attached to one end of a single piezoelectric actuator.
As shown, the
rotational precision of the electric stepper motor would not be high, and it
would not be possible
to make this embodiment as precise as the previously described embodiments due
to the
inherent properties of the type of magnetic material used. It is preferred to
use this embodiment
of the invention in applications where fine control is less important than
simplicity and lower
cost.
[00231] Electric stepper motor 80 comprises rotor assembly 82, stator
magnet
assemblies 84 and 87, and piezoelectric actuator 810 which is operably affixed
to PCB 92
(NOT SHOWN: See FIGURE 22.) Rotor assembly 82, which is free to rotate
relative to all
stator assembly components and is attached to whatever rotational load (NOT
SHOWN) it is
desired to accelerate with the motor, is comprised of magnetic material (or
can have an inner
section of magnetic material surrounded by non-magnetic material as desired)
which has
magnetic regions, each magnetic region having a north pole and a south pole
such as rotor
north poles 82a and 82b and rotor south poles 83a and 83b. Opposite the rotor
assembly's
magnetic material, separated by a gap (See FIGURE 22,) are stator magnet
assemblies 84 and
87. It is possible to construct this embodiment of the invention with a single
stator magnet
3021P-MBE-CAD1 50
Date Recue/Date Received 2022-02-28
assembly, but it is strongly preferred to use two symmetrical stator magnet
assemblies as shown
for purposes of balance and to maximize the piezoelectric actuator's
efficiency.
[00232] First stator magnet assembly 84, similarly to rotor section 82,
is composed in
whole or in part of magnetic material, which has multiple magnetic regions,
each magnetic
region having a north pole such as stator north poles 85a and 85b and rotor
south poles 86a and
86b. Second stator magnet assembly 87, is likewise composed in whole or in
part of magnetic
material, which has multiple magnetic regions, each magnetic region having a
north pole such
as stator north poles 85a and 85b and stator south poles 86a and 86b.
[00233] FIGURE 22 shows a cutaway view of the third alternate
embodiment of the
invention for additional clarity of disclosure. Electric stepper motor 80 has
gap 91, which
separates the various motor assemblies (see FIGURE 21) and allows the motor to
also serve as
a no-contact magnetic bearing so long as the planar load does not materially
affect the gap as
maintained by the magnetic fields of the rotor magnet assembly and the stator
magnet
assemblies. This is an additional advantage of several of the embodiments and
configurations
of the invention disclosed herein. PCB 92 is a printed circuit board which is
both mechanically
and electrically affixed to piezoelectric actuator 810 and provides it with
electrical potential
from a switching power supply (NOT SHOWN.)
[00234] To practice this aspect of the invention, an electrical
potential is put across
piezoelectric actuator 810, which is electrically connected to PCB 92. This
causes piezoelectric
actuator 810 to expand along its long axis, changing the relative position of
the stator magnet
assemblies and the rotor assembly.
[00235] This in turn causes electromagnetic force to be exerted on the
rotor assembly,
which will rotate to a position which will minimize the magnetic potential
energy between the
rotor assembly and the stator assemblies. The electrical potential across
piezoelectric actuator
810, is then removed and/or reversed, causing it to contract along its long
axis, again changing
the relative position of the various magnet assemblies, and imparting more
rotational energy to
the rotor assembly. A switching power supply (NOT SHOWN) continuously cycles
the
electrical potential across the piezoelectric actuator to produce the desired
rotational energy as
in earlier described embodiments.
3021P-MBE-CAD1 51
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[00236] It is optional, but neither preferred nor required, for either
the rotor assembly or
the stator assembly, or both, to comprise multiple magnets as in earlier
described
configurations. (See FIGURE 12, FIGURE 13, and/or FIGURE 17.) So long as the
rotor
assembly and the stator assembly are configured as shown, the configuration of
this third
alternate embodiment incorporating a single piezoelectric actuator will
function and provide
the benefits of the invention.
[00237] Alternate configurations of this aspect the invention, which
can be applied to
any of the described embodiments, will now be disclosed.
[00238] In a first alternate configuration of this aspect (NOT SHOWN)
some or all of
.. the rotor magnets, or some or all of the stator magnets, of either the
preferred embodiment or
the first alternate embodiment are replaced with electromagnets.
[00239] In a second alternate configuration of this aspect (NOT SHOWN)
one or more
elastic members is fitted into the motor assembly such that the piezoelectric
actuators are
working against the elastic members when they are energized, compressing them
and creating
.. elastic potential energy, so that when the piezoelectric actuator(s) is/are
de-energized, the
magnet(s) affixed to the piezoelectric actuator(s) return to their prior
position more quickly and
without the need to impose a reverse polarity potential across the
piezoelectric actuator when
the elastic potential energy provides impetus to the piezoelectric actuators.
[00240] In a third alternate configuration of this aspect (NOT SHOWN)
the features of
the first and second configurations are combined.
[00241] In many of the described embodiments and if necessary, fluid
can be forcibly
circulated around the assemblies or even through the gap(s) to cool the motor,
but as many
piezoelectric devices actually work better when they reach a relatively high
operating
temperature, the need for cooling will be minimal in many applications. This
is another
advantage of the invention. It is required that for all embodiments and
configurations of the
invention, that operating temperatures be kept low enough to avoid
demagnetization of any
permanent magnets which are used. This will vary as various kinds of magnetic
material have
different demagnetization thresholds. (For example, some ferrite magnets can
tolerate
temperatures up to 250 C, whereas some rare-earth magnets can only tolerate
temperatures up
.. to 100 C.)
3021P-MBE-CAD1 52
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[00242] It will be apparent to those of ordinary skill in the art that
while this aspect of
the invention and its preferred embodiments are described in terms of rotary
motors, the
principles taught by the invention can be used to create linear motors, such
as reciprocating
motors, by using the basic principle of piezoelectric motivation of opposing
magnetic elements
to create a linear force instead of a centripetal force. Thus, the claims
below include both rotary
configurations and linear configurations where and as appropriate.
ELECTRIC MOTOR WITH POSITIONAL SENSING
[00243] In acccordance with another aspect of the disclosure, an
electric motor with
positional sensing 10 will now be described.
[00244] For purposes of this aspect, piezoelectric actuators are described
as being
"electrically connected" to a power supply. Such a connection can be made via
physical
conductors (wires, PCB conductive paths, conductive inks, etcetera) or by any
other reasonable
means that allows the power supply to supply energy to the piezoelectric
actuators and causes
the piezoelectric effect to change the dimensions of the piezoelectric
actuators. This includes,
but is not limited to, electromagnetic induction or transfer by capacitance.
It is required that
the means of electrical connection be able to switch the piezoelectric
actuators on and off and/or
apply a current flow in one direction and then in the other direction fast
enough to allow the
motor to operate, as will be made clear in the specification below. This will
be referred to
generally as "rise" time ¨ the period of time it takes to energize the
piezoelectric actuator and/or
the capacitator powering it ¨ and the "fall" time ¨ the period of time it
takes to deenergize the
piezoelectric actuator and/or the capacitor powering it.
[00245] For purposes of this aspect, motors will generally have a group
of components
which remains static relative to a load, and a second group of components
which will move
relative to the first group of components. The first group of components will
be referred to
collectively as a stator assembly, and the second group referred to
collectively as a rotor
assembly. Prefixing a component with the word "rotor" or "stator" indicates
which group of
components it belongs to in the embodiment/configuration which is currently
being described.
Piezoelectric actuators in the stator assembly are stator piezoelectric
actuators (or simply stator
actuators) and magnets affixed to stator piezoelectric actuators are stator
magnets, and vice
versa with regard to the rotor assembly. At the same time, for purposes of
this aspect, magnets
3021P-MBE-CAD1 53
Date Recue/Date Received 2022-02-28
can also be described as falling into one or both of two distinct types
independent of whether
they are part of the stator assembly or the rotor assembly. Actuator magnets
are magnets which
have/are having force imposed upon them by a piezoelectric actuator. Response
magnets are
magnets which have/are having force imposed upon them via magnetic field
interactions with
actuator magnets. If only one group of magnets is affixed to piezoelectric
actuators, those are
the actuator magnets, and the rest of the magnets in the motor are response
magnets. If multiple
groups of magnets are affixed to piezoelectric actuators, magnets affixed to a
piezoelectric
actuator which is being energized and causing it to impose force on those
magnets are actuator
magnets, and magnets which are not so affixed, or which are affixed to a
piezoelectric actuator
which is not being energized, are response magnets. It is possible for any
given magnet to be
an actuator magnet or a response magnet or both at any given time depending on
the motor
controller's configuration and energization of the piezoelectric actuators. A
rotor magnet or a
stator magnet may at any time be an actuator magnet, a response magnet, or
both.
[00246] By referring to FIGURE 23, the basic nature of the electric
motor with
positional sensing 10 can be easily understood. Outer rotor housing 11
surrounds bearing 12
which is free to rotate on balls 13, which bear the load between the motor and
whatever it is
mounted in and whatever it is driving. Inner rotor element 14 has multiple
rotor magnets 15
having rotor north poles 15a and rotor south poles 15b. Any suitable magnet
may be used for
rotor magnets 15, including but not limited to rare-earth magnets,
ferromagnets, and/or ceramic
magnets containing ferromagnetic and/or rare-earth magnetic particles.
Electromagnets may
also be used. If electromagnets are used, it is optional, but neither
preferred nor required, to
allow them to reverse polarity as driven by a solid-state commutator of the
type found in
traditional brushless electric motors.
[00247] Stator assembly 19 consists of central hub 18, which supports
multiple stator
piezoelectric actuators 17. Stator piezoelectric actuators 17 have a magnet
mount end 17a and
a hub end 17b. Stator piezoelectric actuators 17 are connected to a switching
power supply (not
shown) which can energize the stator piezoelectric actuators at any reasonable
driving
frequency. When the stator piezoelectric actuators are energized, they expand,
using the
principle of piezoelectric expansion, also known as the piezoelectric effect,
which is well
known to persons of ordinary skill in the art. Stator piezoelectric actuators
17 are constructed
so that their expansion is along their long axes: in other words, when the
stator piezoelectric
3021P-MBE-CAD1 54
Date Recue/Date Received 2022-02-28
actuators are energized, the distance between magnet mount end 17b and hub end
17a
increases.
[00248] Mounted to magnet mount ends 17b are stator magnets 16, having
stator north
poles 16a and stator south poles 16b. Any suitable magnet may be used for
stator magnets 16,
including but not limited to rare-earth magnets, ferromagnets, and/or ceramic
magnets
containing ferromagnetic and/or rare- earth magnetic particles. Electromagnets
may also be
used. If electromagnets are used, it is optional, but neither preferred nor
required, to allow them
to reverse polarity as driven by a solid-state commutator of the type found in
traditional
brushless electric motors.
[00249] It is strongly preferred that the rotor magnets and the stator
magnets have the
same poles (north and north or south and south) in opposition at their closest
points (as shown)
but with proper configuration, it is possible to practice the invention with
the rotor magnets
and the stator magnets having opposite poles (north and south or south and
north) in opposition.
If opposite poles are put into opposition, the motor may require an external
initiating force
and/or the stator piezoelectric actuators may be required to be energized in a
staggered
sequence. If reversible electromagnets are used for either the rotor magnets,
the stator magnets,
or both, the question of initial polarities is unimportant.
[00250] The preferred embodiment pictured in FIGURE 23 shows the
invention ready
to be practiced. The magnetic forces from the rotor magnets and the stator
magnets are at a
point of equilibrium where the magnets are in the lowest possible potential
energy state with
regard to the magnetic repulsion between the rotor magnets and the stator
magnets. Inner rotor
element 14 will, absent the addition of energy from some exterior source,
remain at this point
of equilibrium indefinitely.
[00251] To practice the invention, stator piezoelectric actuators 17
are energized. This
causes the distance between hub end 17b and magnet mount end 17a to increase,
pushing stator
magnet 16 closer to rotor magnet 15. This increases the magnetic repulsion
between the rotor
magnet and the stator magnet, disturbing the equilibrium between them. In the
configuration
shown, it may be necessary to impart a slight initial rotational force and/or
to energize the stator
piezoelectric actuators in sequence so as to asymmetrically disturb the
equilibrium of magnetic
forces and allow rotation to begin.
3021P-MBE-CAD1 55
Date Recue/Date Received 2022-02-28
[00252] Once the equilibrium between the rotor magnets and the stator
magnets is
disturbed, the system will have more magnetic potential energy than before,
which will cause
the rotor magnets to exert a force on inner rotor 14. Inner rotor element 14
is free to rotate, so
it will rotate in one direction or the other as impelled by the balance of
forces. As will be shown
in later figures, control of the shape and orientation of the rotor magnets
and/or stator magnets
will allow for a preferred direction of rotation.
[00253] The switching power supply is controlled by a frequency
controller (not shown)
which causes it to energize and de-energize stator piezoelectric actuators 17
at a frequency
which will continue to convert magnetic potential energy into rotational
energy and accelerate
inner rotor element 14 in a rotational fashion. It is preferred, but not
required, that sensors (not
shown) be operably connected to the inner rotor element or otherwise be able
to detect its
angular velocity, and communicate it to the frequency controller such that the
frequency
controller can adjust the driving frequency to increase or decrease the force
exerted by the
stator magnets on the rotor magnets and thus either increase the speed of
rotation (under
constant load,) increase the applied torque (under increasing load,) or both.
[00254] To obtain the benefits of the positional sensing aspect of the
invention, the
frequency controller is connected to, or integrated with, a counting device,
an induced current
sensor, or both.
[00255] If a counting device is used, the frequency controller is
connected to or
integrated with the counting device (not shown,) which can detect each
instance of a current
being induced by the rotor magnets rotating past the stator magnets. The
counting device could
be as simple as a circuit in the frequency controller which can detect back-
currents or it can be
a more sophisticated separate device as is appropriate to the application in
which the electric
motor with positional sensing is being used.
[00256] Because the geometry of the rotor magnets and the stator magnets is
known, the
amount of rotational arc the motor, or any element attached to it, goes
through each time the
rotor magnets rotate past the stator magnets is also known. For instance, if
the rotor
magnet/stator magnet pairs each encompass an arc of 10 degrees (or it /18
radians) of the
rotation of the motor, each instance of a current induction equals a rotation
of 10 degrees (or it
/18 radians). To obtain distance moved, the diameter of the circle described
by the element
3021P-MBE-CAD1 56
Date Recue/Date Received 2022-02-28
whose position is to be measured is multiplied times the number of current
inductions and
hence the number of fractional rotations. In a device with a positional
element located one
meter from the center of the rotor, each current induction / movement of the
rotor and stator
magnets would equate to an angular movement of:
[00257] 2 * n * 1 meter * 10 degrees / 360 degrees = it /16 meters (or
¨19.6cm) (Where
2 * n * r is the formula for the circumference of a circle with
[00258] radius r and the circle here has a radius of one meter.)
[00259] It is trivial to derive the angular velocity of the positional
element once its
angular motion is known: the amount of distance traveled in the prior step is
simply divided by
the time it took for the element to move that distance. If it took 0.1 seconds
for the positional
element in the prior example to move through an arc of 10 degrees (or it /18
radians) and thus
move it /16 meters then the angular velocity would be:
[00260] it /16 meters / 0.1 seconds = it /1.6 meters/second (or ¨1.96
m/s)
[00261] It is required that the counting device be able to keep track
of the motion of the
motor whether or not the piezoelectric actuators are being energized by the
switching power
supply in some fashion. It is strongly preferred, but not required, that the
counting device be
able to separately keep track of both the currents which are induced into the
motor by the
switching power supply (for causing the actuators to move the stator magnets
and thus turn the
rotor assembly) and currents which are induced into the motor by countermotion
of the load or
.. other elements attached to the rotor assembly which cause it to rotate by
the imposition of an
external torque. It is optional, but neither preferred nor required, for the
frequency counter to
interact with the counting device in such a way as to calibrate the number of
current inductions
the frequency controller has initiated with the number the counting device
detects so that the
counting device has a redundant source of information it can use to ensure
that current
inductions are being counted correctly.
[00262] If an induced current sensor is used, the frequency controller
is connected to or
integrated with the counting device (not shown,) which can dynamically detect
the induced
current of a current being induced by the rotor magnets rotating past the
stator magnets. The
induced current sensor can be as simple as a circuit in the frequency
controller which can detect
3021P-MBE-CAD1 57
Date Recue/Date Received 2022-02-28
back- currents or it can be a more sophisticated separate device as is
appropriate to the
application in which the electric motor with positional sensing is being used.
[00263] To use the induced current sensor, the electric motor with
positional sensing is
operably connected to another motor or other device (hereafter the
"calibration load") which
can rotate the electric motor with positional sensing without having to apply
power to the
piezoelectric actuators. It is strongly preferred to use the calibration load
to rotate the rotor
assembly, but depending on the needs of the particular application, it is
optional to use the
calibration load to rotate the stator assembly. Whichever of the rotor/stator
assemblies is being
rotated, it is required that the other either be held static or that its
motion be somehow separately
measured to allow for full calibration. The former is strongly preferred.
[00264] Once the calibration load is connected (for illustration the
following will assume
that the stator assembly and the rest of the motor as a whole is being held
static and the rotor
assembly is being rotated by the calibration load) it is used to accelerate
the rotor assembly at
a known rate until it is spinning at a known and fixed angular velocity. On a
first calibration
pass, the induced current sensor is used to dynamically track the current
induced in the electric
motor with positional sensing by the motion of the rotor magnets past the
stator magnets. It is
strongly preferred that the motor be rotated for several revolutions to obtain
a good set of
average values. Because no two of the rotor magnets and/or stator magnets will
have exactly
the same magnetic strength (this can be varied by design or the inevitable
inconsistencies in
manufacture can be used) the induced current sensor will track the current
being induced as a
variable periodic wave (the "base wave.")
[00265] As the base wave will be unique, at sufficient precision of
measurement, at each
point in the rotation of the rotor assembly to any reasonable level, it can be
used to map the
magnetic field of the rotor magnets relative to the stator magnets. This data
is stored for a later
step in the process.
[00266] It is optional but strongly preferred to then repeat the
calibration steps above
with the piezoelectric actuators energized by the stepping power supply,
creating
measurements of another variable periodic wave, the "energized" wave. This can
be done at
any reasonable level of energization, but it is required that the calibration
load have sufficient
power to rotate the motor against the resulting (potentially) increased
magnetic
3021P-MBE-CAD1 58
Date Recue/Date Received 2022-02-28
attraction/repulsion, especially if the motor starts out from a dead stop. As
will be apparent to
persons of ordinary skill in the art, the "back-current" which will be
measured if the
piezoelectric actuators are energized by the power supply will be the sum of
the current being
induced by the power supply and the current being induced by the calibration
load, which will
not be in phase, and the measurements must be used accordingly when using the
energized
wave in later steps.
[00267] It is optional to first spin up the motor with the frequency
controller and then
apply the calibration load with (and against) up to full energization of the
piezoelectric
actuators. This will create yet another variable periodic wave or waves (the
base wave and all
of the energized waves collectively the "waves.") All of the waves should be
quite similar to
the base wave when adjusted for the current being supplied by the power
supply, but will
contain additional minute variations. This data is also stored for a later
step in the process. It is
optional, but not preferred, to use multiple levels of energization, or even
to only used an
energized level and not measure the base wave.
[00268] Once the waves are measured and the data stored, it is used to
construct a map
of the magnetic fields of the rotor and stator magnets (the "field map.") To
practice the
invention using the induced current sensor, the motor is put into operation,
and the point on the
map of the magnetic fields where the rotor assembly is located is determined
at a time or times
when the position of the rotor is to be determined. This is known as
"resolving" the motor or
.. resolving the rotor position.
[00269] It is optional, but strongly preferred, to use some exterior
sensor to measure any
material external electromagnetic fields, variations in temperature, et
cetera, which might
affect the nature of the waves when using the positional sensing capability of
the motor. While
the relative positions of the rotor magnets and stator magnets should produce
consistently
shaped waves, the actual amplitude and frequency of the waves, and thus the
precision of the
positional sensing, will vary according to these and other factors which will
be apparent to
those of ordinary skill in the art.
[00270] Although the preferred embodiment is described as an electric
motor with
positional sensing, which is designed to convert electrical potential from a
switching power
supply into rotational energy, it will be apparent to persons of ordinary
skill in the art that since
3021P-MBE-CAD1 59
Date Recue/Date Received 2022-02-28
the piezoelectric effect works both ways ¨ electrical potential can be turned
into mechanical
force, and mechanical force can be turned into electrical potential ¨ that the
preferred
embodiment can also serve as a generator of electrical power if an external
load forces the inner
rotor element to rotate against the magnetic force attempting to hold it in
equilibrium.
.. Similarly, the preferred embodiment can also be used as a drive motor which
also provides
regenerative braking by switching from power in (during drive mode) to power
out (during
regenerative braking mode.) All of the alternate
configurations/embodiments/methods of
practice described in this paragraph are applicable to all of the embodiments
of the invention
disclosed in this application.
[00271] Additional embodiments of the electric motor with positional
sensing will now
be described. All of the additional embodiments are alternate configurations
of the physical
motor itself: the principles by which each embodiment can be used as an
electric motor with
positional sensing is identical to that described above.
[00272] FIGURE 24 shows a first alternate embodiment of the electric
motor with
positional sensing. The first alternate embodiment of the electric motor with
positional sensing
works in the same general fashion as the embodiment of FIGURE 23, except where
noted
otherwise. It likewise would incorporate a switching power supply, frequency
controller, and
could incorporate sensors, et cetera.
[00273] Electric motor with positional sensing 20 incorporates rotor
piezoelectric
actuators 27b, analogous to stator piezoelectric actuators 17 in FIGURE 23.
[00274] Electric motor with positional sensing 20 also incorporates
stator piezoelectric
actuators 27a. It is neither preferred nor required for either configuration
to be applied with a
single (inner and outer) group of piezoelectric actuators or a double (inner
and outer) group of
piezoelectric actuators: the two configurations are shown for clarity of
disclosure.
[00275] When either stator piezoelectric actuators 27a or rotor
piezoelectric actuators
27b are energized, rotor magnets 25 are pushed toward stator magnets 26, and
as in FIGURE
23, magnetic repulsion is increased, incurring a force against the rotor
piezoelectric actuators.
As the rotor piezoelectric actuators are affixed to outer casing 21, which is
free to rotate relative
to hub 29 on bearing 52 (not identified, see FIGURE 27) which includes race 22
containing
3021P-MBE-CAD1 60
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balls 23, balls 23 bearing the load and allowing rotation of rotary center
bearing element 24
relative to fixed center bearing element 28.
[00276] Depending on the desired method of operation, the stator
piezoelectric actuators
can be activated in concert with the rotor piezoelectric actuators, or only
one or the other group
of piezoelectric actuators can be active at any given time. Activating both at
once can be used
to increase torque/rotational velocity, whereas activating only one or the
other can be used for
lower output modes. Alternatively, one group of piezoelectric actuators can be
wired to deliver
input power (motor driving) and the other group wired to receive output power
(generation/regenerative braking.) The groups of piezoelectric actuators can
also be wired such
that some of the actuators in each group are preferentially used to deliver
input power and some
are preferentially used to receive output power. Finally, all or fewer than
all of the piezoelectric
actuators in a particular group can be active at any given time to deliver any
particular desired
amount of input power or receive any particular desired amount of output
power, allowing an
additional means of controlling power flow and/or reducing electrical fatigue
on the individual
components as they are cycled in and out of service.
[00277] FIGURE 25 shows the first alternate embodiment in cutaway form.
Electric
motor with positional sensing 20, having the same components as in FIGURE 24,
is surrounded
by backing plate 33 and housing 31, while hollow shaft 32, which is operably
affixed to hub
29 (see FIGURE 24) and/or rotary center bearing element 24, allows either
delivery of
mechanical rotational energy (motor mode) or input of mechanical rotational
energy
(generation/regenerative braking mode.)
[00278] FIGURE 26 shows a pair of opposing piezoelectric actuators and
their
corresponding magnets in detail. Stator piezoelectric actuator 27b is affixed
to stator magnet
which has stator north pole 25a and stator south pole 25b. Rotor piezoelectric
actuator 27a
25 is affixed to rotor magnet 26 which has rotor north pole 26a and rotor
south pole 27a. It is
preferred, but not required, that the rotor magnets and the stator magnets be
asymmetrical to
each other (that is, the rotor magnets are not symmetrical with the stator
magnets, shown here
as their being different sizes) to make it easier to overcome the tendency of
the system to "lock"
into a position of minimized magnetic potential energy. Since the magnets are
not symmetrical,
when they are moved in relation to each other the corresponding magnetic
fields will tend to
push more in one direction than the other, overcoming such locking symmetry.
3021P-MBE-CAD1 61
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[00279] FIGURE 27 shows a more complete assembly of the first alternate
embodiment
of the invention for clarity of disclosure. Axial bolt 51 holds the assembly
together and keeps
the rotary elements on-center. Bearing 52 incorporates rotary center bearing
element 24, race
22, balls 23, and fixed center bearing element 28. (See FIGURE 24 for more
detail.)
[00280] FIGURE 28 shows a second alternate embodiment of the electric motor
with
positional sensing with a more complex configuration of rotor magnets and
stator magnets.
This configuration, while not required, is somewhat preferred as it provides
multiple benefits
to the practice of the invention at the price of higher complexity and cost of
manufacture.
[00281] Electric motor with positional sensing 60 comprises rotor
assembly 614 and
stator assembly 618. Rotably affixing the rotor assembly to the stator
assembly is bearing 652
which rotates around central point 611. Mechanically affixed to bearing 652
are one or more
stator piezoelectric elements. Shown is a configuration with six such stator
piezoelectric
elements including stator piezoelectric element 619. Mechanically affixed to
the stator
piezoelectric elements are stator magnet elements such as stator magnet
element 640. The stator
magnet elements comprise one or more magnets having a north pole and a south
pole, such as
stator magnet 617 having stator magnet north pole 617a and stator magnet south
pole 617b.
There is a gap between the stator magnet elements and one or more rotor magnet
elements.
Shown is a configuration with six such rotor magnet elements including rotor
magnet element
642. Each rotor magnet element includes one or more rotor magnets such as
rotor magnet 616,
which has rotor magnet north pole 616a and rotor magnet south pole 616b.
[00282] To practice this aspect of the invention, as with prior
described embodiments,
one or more of the stator piezoelectric actuators, such as stator
piezoelectric actuator 619, is
energized by a switching power supply (NOT SHOWN) controlled by a frequency
controller
(NOT SHOWN) such that when, for example, stator piezoelectric actuator 619 is
energized, it
expands along axis of expansion 619a, causing the corresponding stator magnet
element to get
closer to one or more rotor magnet elements. This produces a change in the
orientation of the
magnetic fields of the stator and rotor magnetic elements, causing the
corresponding stator
magnetic element to exert a force on the rotor magnetic element which in turn
causes the rotor
magnet element to exert a force on the housing 612, causing it, along with the
entire rotor
assembly 614 to rotate around central point 611 on bearing 652 relative to
stator assembly 618.
3021P-MBE-CAD1 62
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This rotational force is transmitted to an external load via hollow shaft 632
(NOT SHOWN,
see FIGURE 29.)
[00283] It is not required that each rotor magnet element be exactly
geometrically
opposed to a stator magnet element at any particular time during operation or
non-operation
and in fact it is likely that the equilibrium during non-operation will result
in some degree of
offset. It is strongly preferred that there be a rotor magnet element for each
stator magnet
element, and vice versa. It is required that there be a gap between the rotor
magnet elements
and the stator magnet elements sufficient to allow the rotor magnet elements
to move freely
without contacting the stator magnet elements under any reasonable amount of
bearing load,
rotary speed, or transient vibratory load.
[00284] Although the configuration of magnets shown will be inherently
stable due to
magnetic attraction between the individual magnets, it is preferred that the
magnets in each
rotor magnet element and stator magnet element be epoxied or otherwise
physically affixed to
each other to maintain the desired alignment and prevent shifting under load
or due to vibration
.. or other transient phenomena.
[00285] It is strongly preferred, but not required, to use an
overlapping configuration of
magnets as shown in the rotor magnet elements and the stator magnet elements
as this will
minimize asymmetries in the overall magnetic field structure in the brushless
magnetic motor.
FIGURE 7 shows a more complete assembly of the second alternate embodiment of
the
invention for clarity of disclosure along with the addition of an optional set
of stator
piezoelectric actuators as in FIGURE 24. (See FIGURE 28 for more detail.)
Axial bolt 651
holds the assembly together and keeps the elements on-center. Capacitor array
bolts 680 affix
capacitor array 656 to base element 682 by means of threaded receivers 681.
Although shown
as traditional capacitive plates, any desired means of capacitive induction of
current, such as
vacuum-tube capacitors, can be used.
[00286] For purposes of this description, it is assumed that base
element 682 is secured
to something which is designated as static and therefore base element 682
forms part of a stator
assembly. For example, if motor 60 were to be used to drive the wheel of an
electric vehicle,
base element 682 would ultimately be statically affixed to the chassis of the
vehicle, whereas
housing 612 would ultimately be statically affixed to the wheel of the
vehicle.
3021P-MBE-CAD1 63
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[00287] Capacitor array 680, which does not rotate relative to the
stator assembly,
includes capacitor plates such as capacitor plate 658, each capacitor plate
separated by a gap
such as capacitor gaps 657a and 657b. Capacitor array energizes rotor
piezoelectric array 621,
which includes one or more rotor piezoelectric actuators such as rotor
piezoelectric actuator
621. The rotor piezoelectric actuators are mechanically affixed to one or more
(optional) rotor
magnet brackets 678, each rotor magnet bracket having a rotor circumferential
surface 662,
and (optional) rotor vertical guides 661a and 661b, with all of the rotor
magnet brackets
forming rotor magnet bracket assembly 660. Mechanically affixed to the rotor
piezoelectric
actuators, either directly or via the (optional) rotor magnet brackets, are
one or more rotor
magnet elements such as rotor magnet element 642, each rotor magnet element
comprising one
or more rotor magnets such as rotor magnet 616, with all of the rotor magnet
elements forming
rotor magnet assembly 672.
[00288] When energized, the rotor piezoelectric actuators expand toward
the center of
motor 60 (since they cannot expand against the fixed position of the rest of
the rotor assembly
including ultimately housing 612) pushing the rotor magnet elements toward the
stator magnet
elements (see below) and imparting a magnetic force as explained in previous
descriptions (see
FIGURES 23, 24, and 28.) This ultimately causes the rotor assembly, including
housing 612,
to rotate, allowing for rotary force to be exerted through hollow shaft 632.
The rotor
piezoelectric actuators can be energized one at a time, all together, or in
sequence, as is desired
and appropriate for the load and conditions. The rotor piezoelectric actuators
can be energized
without energizing the stator piezoelectric actuators (see below) or in
concert with them.
[00289] Rotor magnet assembly 672 radially surrounds stator magnet
assembly 670, the
rotor magnet assembly separated from the stator magnet assembly by a gap (NOT
SHOWN,
see FIGURE 31.) Stator magnet assembly 670 comprises one or more stator magnet
elements
such as stator magnet element 640, each stator magnet element comprising one
or more stator
magnets such as stator magnet 617. Stator magnet elements are mechanically
affixed to stator
piezoelectric assembly 669, which includes one or more stator piezoelectric
actuators such as
stator piezoelectric actuator 619, either directly or by means of (optional)
stator magnet bracket
assembly 655. (Optional) stator magnet bracket assembly 655 comprises one or
more stator
magnet brackets such as stator magnet bracket 676, each stator magnet bracket
including a
stator circumferential surface such as stator circumferential surface 654 and
(optional) stator
vertical guides 653a and 653b.
3021P-MBE-CAD1 64
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[00290] When energized, the stator piezoelectric actuators expand
toward the outer
circumference of motor 60 (since they cannot expand toward the fixed position
of the rest of
the stator assembly) pushing the stator magnet elements toward the rotor
magnet elements and
imparting a magnetic force as explained in previous descriptions (see FIGURES
23, 24, and
28.) This ultimately causes the rotor assembly, including housing 612, to
rotate, allowing for
rotary force to be exerted through hollow shaft 632. The stator piezoelectric
actuators can be
energized one at a time, all together, or in sequence, as is desired and
appropriate for the load
and conditions. The stator piezoelectric actuators can be energized without
energizing the rotor
piezoelectric actuators or in concert with them.
[00291] FIGURE 30 shows the configuration of FIGURE 29 in an alternate
phase of
assembly for clarity of disclosure. Housing 612 is ready to be placed over the
rest of the motor
assembly, with capacitor array 656 ready to be secured to base element 682
with capacitor
array bolts 680. The rotor and stator elements are assembled, for example
rotor piezoelectric
actuator affixed to rotor circumferential surface 662 and stator piezoelectric
actuator affixed to
stator circumferential surface 654, and both ready to be inserted into their
respective
assemblies.
[00292] FIGURE 31 shows the configuration of FIGURE 29 in a cutaway
view for
clarity of disclosure. Housing 612 is axially secured by axial bolt 651 but is
free to rotate
relative to base element 682 as they are mechanically connected only by
bearings 652 and 683.
Rotor magnet element 642 is separated from stator magnet element 640 by gap
690. The size
of gap 690 can be changed by energizing stator piezoelectric actuator 619
and/or rotor
piezoelectric actuator 621. As the piezoelectric actuators change the size of
gap 690, the
relative orientation of the magnetic fields of the rotor magnet elements and
the stator magnet
elements will change. This will cause magnetic force to be exerted between
magnet elements,
.. but as only the rotor magnet elements (ultimately connected to housing 612)
can move, the
force will cause housing 612 to move, allowing rotary motion to be imparted to
hollow shaft
632 and thus to an axle, a wheel, or any other rotary member or rotary load
desired.
[00293] FIGURE 32 shows a third alternate embodiment of the invention.
In this
embodiment, rather than a plurality of distinctive magnets, the rotor magnets
comprise a single
piece of rotor magnetic material, which is structured to have a plurality of
magnetic regions,
each magnetic region having a north pole and a south pole. Similarly, there
are two individual
3021P-MBE-CAD1 65
Date Recue/Date Received 2022-02-28
pieces of stator magnetic material having a plurality of magnetic regions.
Each piece of stator
magnetic material is attached to one end of a single piezoelectric actuator.
[00294] Electric motor with positional sensing 80 comprises rotor
assembly 82, stator
magnet assemblies 84 and 87, and piezoelectric actuator 810 which is operably
affixed to PCB
92 (NOT SHOWN: See FIGURE 33.) Rotor assembly 82, which is free to rotate
relative to all
stator assembly components and is attached to whatever rotational load (NOT
SHOWN) it is
desired to accelerate with the motor, is comprised of magnetic material (or
can have an inner
section of magnetic material surrounded by non-magnetic material as desired)
which has
magnetic regions, each magnetic region having a north pole and a south pole
such as rotor
north poles 82a and 82b and rotor south poles 83a and 83b. Opposite the rotor
assembly's
magnetic material, separated by a gap (See FIGURE 33,) are stator magnet
assemblies 84 and
87. It is possible to construct this embodiment of the invention with a single
stator magnet
assembly, but it is strongly preferred to use two symmetrical stator magnet
assemblies as shown
for purposes of balance and to maximize the piezoelectric actuator's
efficiency. First stator
magnet assembly 84, similarly to rotor section 82, is composed in whole or in
part of magnetic
material, which has multiple magnetic regions, each magnetic region having a
north pole such
as stator north poles 85a and 85b and rotor south poles 86a and 86b. Second
stator magnet
assembly 87, is likewise composed in whole or in part of magnetic material,
which has multiple
magnetic regions, each magnetic region having a north pole such as stator
north poles 85a and
85b and stator south poles 86a and 86b.
[00295] FIGURE 33 shows a cutaway view of the third alternate
embodiment of this
aspect of the disclosure for additional clarity. Electric motor with
positional sensing 80 has gap
91, which separates the various motor assemblies (see FIGURE 32) and allows
the motor to
also serve as a no-contact magnetic bearing so long as the planar load does
not materially affect
the gap as maintained by the magnetic fields of the rotor magnet assembly and
the stator magnet
assemblies. This is an additional advantage of several of the embodiments and
configurations
of the invention disclosed herein. PCB 92 is a printed circuit board which is
both mechanically
and electrically affixed to piezoelectric actuator 810 and provides it with
electrical potential
from a switching power supply (NOT SHOWN.)
[00296] If necessary, fluid can be forcibly circulated around the
assemblies or even
through the gap to cool the motor, but as many piezoelectric devices actually
work better when
3021P-MBE-CAD1 66
Date Recue/Date Received 2022-02-28
they reach a relatively high operating temperature, the need for cooling will
be minimal in
many applications. This is another advantage of the invention. It is required
that for all
embodiments and configurations of the invention, that operating temperatures
be kept low
enough to avoid demagnetization of any permanent magnets which are used. This
will vary as
various kinds of magnetic material have different demagnetization thresholds.
(For example,
some ferrite magnets can tolerate temperatures up to 250 C, whereas some rare-
earth magnets
can only tolerate temperatures up to 100 C.)
[00297] To practice an embodiment of this aspect of the invention, an
electrical potential
is put across piezoelectric actuator 810, which is electrically connected to
PCB 92. This causes
piezoelectric actuator 810 to expand along its long axis, changing the
relative position of the
stator magnet assemblies and the rotor assembly. This in turn causes
electromagnetic force to
be exerted on the rotor assembly, which will rotate to a position which will
minimize the
magnetic potential energy between the rotor assembly and the stator
assemblies. The electrical
potential across piezoelectric actuator 810, is then removed and/or reversed,
causing it to
contract along its long axis, again changing the relative position of the
various magnet
assemblies, and imparting more rotational energy to the rotor assembly. A
switching power
supply (NOT SHOWN) continuously cycles the electrical potential across the
piezoelectric
actuator to produce the desired rotational energy as in earlier described
embodiments.
[00298] It is optional, but neither preferred nor required, for either
the rotor assembly or
the stator assembly, or both, to comprise multiple magnets as in earlier
described
configurations. (See FIGURE 23, FIGURE 24, and/or FIGURE 28.) So long as the
rotor
assembly and the stator assembly are configured as shown, the configuration of
this third
alternate embodiment incorporating a single piezoelectric actuator will
function and provide
the benefits of the invention.
[00299] Alternate configurations of this aspect of the disclosure, which
can be applied
to any of the described embodiments, will now be disclosed.
[00300] In a first alternate configuration of this aspect (NOT SHOWN)
some or all of
the rotor magnets, or some or all of the stator magnets, of either the
preferred embodiment or
the first alternate embodiment are replaced with electromagnets.
3021P-MBE-CAD1 67
Date Recue/Date Received 2022-02-28
[00301] In a second alternate configuration of this aspect (NOT SHOWN)
one or more
elastic members is fitted into the motor assembly such that the piezoelectric
actuators are
working against the elastic members when they are energized, compressing them
and creating
elastic potential energy, so that when the piezoelectric actuator(s) is/are de-
energized, the
magnet(s) affixed to the piezoelectric actuator(s) return to their prior
position more quickly and
without the need to impose a reverse polarity potential across the
piezoelectric actuator when
the elastic potential energy provides impetus to the piezoelectric actuators.
[00302] In a third alternate configuration of this aspect (NOT SHOWN)
the features of
the first and second configurations are combined.
[00303] It will be apparent to those of ordinary skill in the art that
while this aspect and
its preferred embodiments are described in terms of rotary motors, the
principles taught by the
invention can be used to create linear motors, such as reciprocating motors,
by using the basic
principle of piezoelectric motivation of opposing magnetic elements to create
a linear force
instead of a centripetal force. Thus, the claims below include both rotary
configurations and
linear configurations where and as appropriate.
[00304] While various embodiments and configurations of the present
invention have
been described above, it should be understood that they have been presented by
way of example
only, and not limitation. Thus, the breadth and scope of the present invention
should not be
limited by any of the above exemplary embodiments.
[00305] This application ¨ taken as a whole with the abstract,
specification, and
drawings being combined ¨ provides sufficient information for a person having
ordinary skill
in the art to practice the invention as disclosed herein. Any measures
necessary to practice this
invention are well within the skill of a person having ordinary skill in this
art after that person
has made a careful study of this disclosure.
[00306] Because of this disclosure and solely because of this disclosure,
modification of
this device and method can become clear to a person having ordinary skill in
this particular art.
Such modifications are clearly covered by this disclosure.
[00307] While the present disclosure describes various embodiments for
illustrative
purposes, such description is not intended to be limited to such embodiments.
On the contrary,
3021P-MBE-CAD1 68
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the applicant's teachings described and illustrated herein encompass various
alternatives,
modifications, and equivalents, without departing from the embodiments, the
general scope of
which is defined in the appended claims. Except to the extent necessary or
inherent in the
processes themselves, no particular order to steps or stages of methods or
processes described
in this disclosure is intended or implied. In many cases the order of process
steps may be varied
without changing the purpose, effect, or import of the methods described.
[00308] Information as herein shown and described in detail is fully
capable of
attaining the above-described object of the present disclosure, the presently
preferred
embodiment of the present disclosure, and is, thus, representative of the
subject matter which
is broadly contemplated by the present disclosure. The scope of the present
disclosure fully
encompasses other embodiments which may become apparent to those skilled in
the art, and is to
be limited, accordingly, by nothing other than the appended claims, wherein
any reference to an
element being made in the singular is not intended to mean "one and only one"
unless
explicitly so stated, but rather "one or more." All structural and functional
equivalents to
the elements of the above-described preferred embodiment and additional
embodiments as
regarded by those of ordinary skill in the art are intended to be encompassed
by the present
claims. Moreover, no requirement exists for a system or method to address each
and every
problem sought to be resolved by the present disclosure, for such to be
encompassed by the
present claims. Furthermore, no element, component, or method step in the
present disclosure
is intended to be dedicated to the public regardless of whether the element,
component, or
method step is explicitly recited in the claims. However, that various changes
and
modifications in form, material, work-piece, and fabrication material detail
may be made, without
departing from the spirit and scope of the present disclosure, as set forth in
the appended claims,
as may be apparent to those of ordinary skill in the art, are also encompassed
by the disclosure.
3021P-MBE-CAD1 69
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