Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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MAGNET COUPLER HAVING ENHANCED ELECTROMAGNETIC
TORQUE
Related Applications
This application claims the benefit of U. S. provisional applications
S Nos. 60/042,986, filed on April 14, 1997; 60/047,284, filed on May 20, 1997;
60/049,630, filed on June 13, 1997; 60/049,994, filed on May S, 1997; and
601051,101, filed on June 27, 1997, all of which are incorporated herein by
reference.
Field of the Invention
The present invention relates to magnetic couplers, and more particularly to
magnet couplers having increased electromagnetic torque.
Background of the Invention
Industrial processes frequently use rotating machinery. The use of rotating
machinery entails coupling a load to a motor. The connection between the load
and
the motor can be a direct physical connection, such as a clutch, a belt and
pulley
system, or in-Iine couplings. All of these direct connections require precise
alignment
of the motor shaft and the load shaft. This precise alignment can be achieved
using
techniques such as laser alignment. However, Iaser alignment is expensive and
time
consuming, and may be ineffective if either the motor shaft or the load shaft
is out of
round.
The use of flexible couplings allows a limited degree of misalignment between
the motor shaft and the load shaft. However, a flexible coupling will wear and
will
' eventually fail. This introduces additional costs and equipment downtime.
An alternative to a direct connection is an electromagnetic coupling. One
example of an electromagnetic coupling is an eddy current coupling. An eddy
current
coupling couples the motor shaft and the load shaft by magnetic fields
produced by
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controlled DC currents. Thus, the motor shaft and load shaft are not
physically
connected. However, an eddy current coupling is expensive, complex, and may be
inappropriate for heavy industrial applications.
Another type of electromagnetic coupling is a permanent magnet coupling. A
permanent magnet coupling couples the motor shaft and the load shaft by
magnetic
fields produced by permanent magnets rather than by controlled DC currents.
The
permanent magnet coupler is simpler, less expensive, and better adapted to
heavy
industrial use than the eddy current coupler. However, the amount of
electromagnetic
torque that can be transferred between the motor shaft and the load shaft by
known
permanent magnet couplers is limited.
An increase in output loading, requiring additional electromagnetic torque,
causes additional slip in permanent magnet couplers known in the art. As slip
increases from zero, a maximum torque, known as "breakdown torque" is
generated.
As slip increases past the slip at which breakdown torque is achieved, known
as
"breakdown slip," the generated torque decreases. This torque-slip
relationship is
shown in FIGURE 1. Breakdown torque is usually about twice the rated torque of
the permanent magnet coupler. Breakdown torque is not ordinarily attained
under
normal, steady state operation, but may be developed under momentary transient
overloads. It would be desirable to increase the slip at which breakdown
torque
occurs in permanent magnet couplers because a higher starting torque would be
achieved. However, as slip increases in permanent magnet couplers, additional
heat is
generated in the conductors due to increased conductor losses. Increased
conductor
losses result in lowered operating efficiency, can cause warping of the
conductor, and
can ultimately lead to failure of the conductor. Thus, there is an unmet need
in the art
for a permanent magnet coupler having an increased breakdown slip and an
increased
starting torque.
The conductor assemblies used in conventional permanent magnet couplers
are made from plates of a conductor, such as copper. The conductor plates must
be
machined. Similarly, permanent magnet assemblies used in conventional
permanent
magnet couplers are also machined. Machining is a complex and costly
manufacturing
process. In order to fabricate conductor assemblies and permanent magnet
assemblies
of various sizes, retooling is required. This retooling further increases the
complexity
and cost. Therefore, there is also an unmet need in the art for permanent
magnet
couplers having permanent magnet assemblies and conductor assemblies that do
not
have the above drawbacks imposed by machining.
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Summary of the Invention
The present invention provides a magnet coupler having increased
electromagnetic torque. The present invention accomplishes
this by providing a
coupler that includes a first shaft having a first axis and
a second shaft that is separate
from the first shaft, The second shaft has a second axis
that is substantially aligned
with the first axis. A first disk is arranged to rotate about
the first shaft. An array of
permanent magnet assemblies is mounted on the first disk.
A second disk is arranged
to rotate about the second shaft. A composite conductor assembly
is mounted on the
second disk. The permanent magnet assemblies and the conductor
assembly are
laterally spaced apart from each other, such that rotation
of the first disk causes
rotation of the second disk due to electromagnetic coupling
between the permanent
magnet assemblies and the conductor assembly.
According to one aspect, the composite conductor assembly
includes a
copper-semiconductor composite. The semiconductor is suitably
silicon. The use of
a copper-semiconductor composite for the conductor assembly
raises the resistance of
the conductor assembly and advantageously raises the slip
at which breakdown torque
occurs. The copper-semiconductor composite is able to withstand
heat generated by
the increased slip without resulting in warping or failure
of the conductor assembly.
Another advantage resulting from the use of a copper-semiconductor
conductor
assembly is that starting torque for the coupler is also
increased.
According to another aspect of the invention, the coupler
further includes a
ferrous backing mounted between the conductor assembly and
the second disk. The
ferrous backing is suitably an electrolytic iron composite.
The use of an electrolytic
iron composite backing increases inductance and compensates
for additional
conductor losses due to the use of the semiconductor in the
conductor assembly.
The present invention increases electromagnetic torque even
further over
torque generated by permanent magnet couplers known in the
art. The present
invention accomplishes this by providing a moment arm that
is greater than that in
permanent magnet couplers currently known in the art. According
to one
embodiment of the present invention, a permanent magnet coupler
includes a first
shaft having a first axis. A second shaft is separate from
the first shaft, and the second
shaft has a second axis that is substantially aligned with
the first axis. A first disk is
arranged to rotate about the first shaft. An array of permanent
magnet assemblies is
mounted on the first disk, and the permanent magnet assemblies
are located radially
about the first disk at a first distance from the first axis.
A second disk is arranged to
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rotate about the second shaft. A composite conductor assembly is mounted on
the
second disk. The composite conductor assembly is located radially about the
second
disk at a second distance from the second axis that is less than the first
distance. The
permanent magnet assembly and the conductor assembly are laterally and
radially
spaced apart from each other, such that rotation of the first disk causes
rotation of the
second disk due to electromagnetic coupling between the permanent magnet
assemblies and the conductor assembly.
The present invention increases the electromagnetic torque even further by
providing an increased surface area of permanent magnets and an increased
surface
area of conductor for cutting through magnetic lines of flux. According to one
aspect
of the invention, the permanent magnet assemblies include first and second
permanent
magnets having first and second faces, and the composite conductor assembly
includes first and second conductor segments that are arranged to face toward
the
first and second faces of the first and second permanent magnets The first and
second
permanent magnets are suitably arranged substantially normal to each other,
and the
first and second conductor segments are suitably arranged substantially normal
to
each other. According to another aspect of the present invention, the
permanent
magnet assemblies include a third permanent magnet having a third face, and
the first,
second, and third permanent magnets are arranged in substantially a U-
configuration.
The conductor assembly includes a third conductor segment that is arranged to
face
the third permanent magnets.
According to another aspect of the present invention, the conductor assembly
and the permanent magnet assembly are fabricated by modular construction. The
conductor assemblies include a plurality of individual conductor elements that
may be
any suitable shape as desired. The individual conductor elements link
together, and
varying the number of individual conductor elements that are linked together
varies
the diameter of the conductor assembly.
According to another aspect of the present invention, the permanent magnet
assembly is also fabricated using modular construction techniques similar to
those
used for the conductor assembly.
Brief Description of the Drawings
The foregoing aspects and many of the attendant advantages of this invention
will become more readily appreciated as the same becomes better understood by
reference to the following detailed description, when taken in conjunction
with the
3 5 accompanying drawings, wherein:
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FIGURE 1 is a graph of torque versus slip speed for prior art permanent
magnet couplers;
FIGURE 2 is a perspective view of a permanent magnet coupler according to
the present invention, with part of the magnet disk removed for detail;
FIGURE 3 is an exploded view of the permanent magnet coupler of
FIGURE 2;
FIGURE 4 is a front plan view of the magnet unit of the permanent magnet
coupler of FIGURE 2;
FIGURE 5 is a front plan view of an alternate rotary magnet unit of the
permanent magnet coupler of FIGURE 2;
FIGURE 6 is a sectional view of the magnet assembly of the permanent
magnet coupler of FIGURE 2 taken along the section lines 6--6 of FIGURE 4;
FIGURE 7 is a front plan view of an alternate conductor assembly for the
permanent magnet coupler of FIGURE 2;
FIGURE 8 is a graph of torque versus slip speed for the permanent magnet
coupler of the present invention;
FIGURE 9 is a sectional view of the conductor assembly of FIGURE 2 taken
along the section lines 9--9 of FIGURE 7;
FIGURE 10 is a plan view of an alternate conductor assembly for the
permanent magnet coupler of FIGURE 2;
FIGURE 11 is a diagrammatic side view of an alternate permanent magnet
coupler according to a first embodiment of the present invention;
FIGURE 11A is a diagrammatic side view of an alternate permanent magnet
coupler according to the first embodiment of the present invention;
FIGURE 11B is a diagrammatic side view of yet another permanent magnet
coupler according to the first embodiment of the present invention;
FIGURE 12 is a diagrammatic side view of a permanent magnet coupler
according to a second embodiment of the present invention;
FIGURE 12A is a diagrammatic side view of an aspect of an alternate
permanent magnet coupler according to the second embodiment of the present
invention;
FIGURE 13 is a diagrammatic side view of a permanent magnet coupler
according to a third embodiment of the present invention;
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FIGURE 13A is a diagrammatic side view of an alternate arrangement of the
permanent magnet coupler according to the third embodiment of the present
invention;
FIGURE 13B is a diagrammatic side view of yet another arrangement of a
permanent magnet coupler according to the third embodiment of the present
invention;
FIGURE 13C is a diagrammatic side view of still another arrangement of the
permanent magnet coupler according to the third embodiment of the present
invention;
FIGURE 14 is a diagrammatic side view of a permanent magnet coupler
according to a fourth embodiment of the present invention;
FIGURE 15 is a rear perspective view of a permanent magnet coupler
according to a fifth embodiment of the present invention;
FIGURE 16 is a diagrammatic side view of the permanent magnet coupler of
FIGURE 15;
FIGURE 17 is a perspective view of the magnet rotor assembly for the
permanent magnet coupler of FIGURE 15;
FIGURE 18 is an exploded perspective view of the magnet rotor assembly of
FIGURE 17;
FIGURE 19 is a perspective view of a permanent magnet used to form one of
the magnetic assemblies for the magnet rotor assembly of FIGURE 17;
FIGURE 19A is a perspective view of alternate permanent magnet for use in
the magnet rotor assembly of FIGURE 17;
FIGURE 20 is a perspective view of a magnet holder of the magnet assembly
shown in FIGURES 18 and 19;
FIGURE 21 is a perspective view of a conductor rotor assembly for the
permanent magnet coupler of FIGURE 15;
FIGURE 22 is an exploded perspective view of the conductor rotor assembly
of FIGURE 21;
FIGURE 23 is a perspective view of a conductor rotor component of the
conductor rotor assembly ofFIGURE 21;
FIGURE 24 is a perspective view of an alternate arrangement of the
conductor rotor component of FIGURE 23;
FIGURE 25A is a plan view of an alternate rotor assembly according to the
3 5 present invention;
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FIGURE 25B is a link subassembly for fabricating the rotor assembly of
FIGURE 25A;
FIGURE 26 is a perspective view of a variable speed magnetic drive coupler
having a moving motor stand;
- 5 FIGURE 27 is a plan view of a conductor rotor assembly formed according to
the modular rotor components provided by the present invention;
FIGURE 28 is a plan view of yet another conductor rotor assembly formed by
the modular components used in FIGURE 27 and additional modular components;
FIGURE 29 is a plan view of still another conductor rotor assembly formed
from the modular components of FIGURE 28 and still more modular components;
FIGURE 30 is a plan view of a four-element magnet holder of a magnet
assembly according to another aspect of the present invention; and
FIGURE 31 is an exploded view of the four-element magnet holder of
FIGURE 32;
FIGURE 32 is a perspective view of a hexagon-shaped link rotor assembly
according to another aspect of the present invention;
FIGURE 33 shows the female side of the hexagonal link rotor assembly of
FIGURE 3 2;
FIGURE 34 shows the male side of the hexagonal link rotor assembly of
FIGURE 32;
FIGURE 35 is a bottom view of a magnet rotor formed using the hexagonal
rotor assembly ofFIGURE 32;
FIGURE 36 is a bottom view of two magnet holders for use in the magnet
rotor of FIGURE 3 5;
FIGURE 37 shows a bottom view of an alternate magnet rotor formed from
the hexagonal rotor assembly of FIGURE 32;
FIGURE 38 is a bottom view of a conductor rotor using the hexagonal rotor
assembly of FIGURE 32;
FIGURE 39 is a perspective view showing the male side of another hexagonal
link that may be used to make a rotor assembly according to another aspect of
the
present invention;
FIGURE 40 is the female side of the hexagonal link of FIGURE 39;
FIGURE 41 is a top view of an assembly of hexagonal links as shown in
FIGURE 39;
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FIGURE 42 is a sectional view of the assembly of FIGURE 41 taken along the
section lines 42--42 of FIGURE 41;
FIGURE 43 is a top perspective view of the assembly of FIGURE 41;
FIGURE 44 is a perspective view of an exemplary snap-ring fastener used to
connect the hexagon links of FIGURE 41;
FIGURE 45 is a perspective view of the underside of the assembly of
FIGURE 41;
FIGURE 46 shows a detail of the snap-ring fastener of FIGURE 44 fastening
the hexagon links of FIGURE 41 together;
FIGURES 47 and 48 show perspective views of exemplary magnet holders
that may be used with the hexagon links of FIGURES 39-46;
FIGURE 49 is a perspective view of an assembled magnet rotor assembly
including hexagon links, magnet holders, and magnets of FIGURES 39-48;
FIGURE 50 shows an variable speed coupler embodiment of the present
invention illustrating a variable resistor connected in parallel with the
conductor rotor
assembly;
FIGURE 51 shows a embodiment of the present invention containing
ferrofiuid in the fixed gap between the magnets and the conductors of the
coupler;
FIGURE 52 shows a side perspective view of an additional hexagonal link
structure for use in the invention;
FIGURE 53 shows a top view of the hexagonal link structure of FIGURE 52;
FIGURE 54 shows a side view of the hexagonal link structure of FIGURE 52;
FIGURE 55 shows a side perspective view of three assembled hexagonal link
structures such as is shown in FIGURE 52; and
FIGURE 56 shows a side perspective view of two assembled hexagonal link
structures such as is shown in FIGURE 52.
D etailed Description of the Preferred Embodiment
FIGURES 2 and 3 show a permanent magnet coupler 10 according to the
present invention. The coupler 10 includes a first shaft 12 having a first
axis 14 and a
second shaft 16 having a second axis 18 that is substantially aligned with the
first
axis 14. A rotary magnet unit 20 is mounted to rotate about the first shaft
12. The
rotary magnet unit 20 includes an array of permanent magnet assemblies 22. A
rotary
electroconductive unit 24 is mounted to rotate about the second shaft 16. The
rotary
electroconductive unit 24 includes a composite conductor assembly 26. The
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composite conductor assembly 26 and the permanent magnet assemblies 22 are
spaced apart from each other. Rotation of the first shaft 12 causes rotation
of the
second shaft 16 due to electromagnetic coupling between the rotary magnet unit
20
and the electroconductive unit 24.
S The first shaft 12 is suitably a motor shaft, and the second shaft 16 is
suitably a
load shaft. However, it is not necessary that the first shaft 12 be a motor
shaft and the
second shaft 16 be a load shaft. The first shaft 12 is also suitably a load
shaft, and the
second shaft 16 is also suitably a motor shaft. The first shaft 12 and the
second
shaft 16 are separated from each other. The first axis 14 and the second axis
18 are
preferably substantially aligned with each other. Longitudinal and radial
misalignment
may be tolerated between the first and second axes 14 and 18, depending upon
the
gap between the rotary magnet unit 20 and the rotary electroconductive unit
24, as
will be discussed more fially below.
The rotary magnet unit 20 includes a disk 28 that is coupled to the first
shaft 12. The permanent magnet assemblies 22 can be spaced in an array around
the
perimeter of the disk 28 in a variety of arrangements as is described in
detail below.
The disk 28 is attached to the first shaft 12 in any one of a number of
acceptable
mounting methods well known in the art, such as hubs (not shown), set screws
(not
shown), keys (not shown), and key-ways (not shown). The disk 28 has a radius
Rl.
It is desirable that the disk 28 have high strength characteristics yet be
lightweight.
Therefore, the disk 28 can be made of aluminum or stainless steel, but is
preferably
made of a composite material, such as RytexTM. In one exemplary embodiment
shown in FIGURE 1 l, given by way of a non-limiting example, the radius RI is
suitably approximately 8 inches, and the disk 28 has a suitable thickness TI
of
approximately '/4 inch. It will be appreciated that it is not necessary that
the disk 28
have these dimensions but, rather, may have any radius and thickness as
desired for a
particular application.
FIGURE 4 shows construction of the permanent magnet assemblies 22. The
permanent magnet assemblies 22 include permanent magnets 23 that are suitably
rare
earth-type magnets, such as lanthanides like samarium, cobalt, and neodymium
iron
boron, as are well known in the art. Neodymium iron boron magnets are
presently
preferred because they have a high flux density and because their domains can
be
preoriented before final magnetization. The permanent magnet assemblies 22 may
be
arranged in any number of acceptable manners. The arrangement of the permanent
3 S magnet assemblies 22 for the embodiments given by way of non-limiting
examples will
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be discussed later. When the permanent magnet assembly 22 includes more than
one
permanent magnet 23, as will be discussed later, all the permanent magnets 23
of the
given permanent magnet assembly 22 are arranged such that the same pole is
oriented
to face a corresponding conductor. The poles of adjacent permanent magnet
assemblies 22 alternate between north and south. The permanent magnets 23 each
have a suitable thickness as desired for a particular application.
As shown in the embodiment given by way of the non-limiting example in
FIGURES 2 and 4, the permanent magnets 23 are suitably arcuate sectors having
arcuate outer and inner circumferential edges. Each permanent magnet 23
contains an
arcuate concave notches 23' (FIGURE 3) on both sides of the permanent magnet
23.
The side walls of these arcuate concave notches 23' are preferably sloped
downward
in a funnel-shaped configuration, as most readily shown in FIGURE 6, and as is
described in detail below.
In addition to the permanent magnet 23, the permanent magnet assemblies 22
each preferably include a non-magnetic spacer 25. As shown in the embodiment
given
by way of non-limiting example shown in FIGURE 4, the non-magnetic spacers 25
are
suitably disks. The disks are shaped and sized such that the circumference of
the disk
substantially conforms to the shape of the arcuate concave notch 23' in the
side of the
permanent magnets 23. This permits the permanent magnets 23 and the non-
magnetic
spacers 25 to be interleaved, as will be discussed in detail below. The non-
magnetic
spacers 25 are attached to the disk 28 with bolts 27 (FIGURE 2) that are
suitably
made of stainless steel.
It will be appreciated that the number and size of permanent magnet
assemblies 22 that are mounted about the disk 28 determines the radial
distance from
the first axis 14 at which the permanent magnet assemblies 22 are located.
Thus, the
use of the permanent magnets 23 and the non-magnetic spacers 25 in the
permanent
magnet assemblies 22 results in a modular construction. As an example, FIGURE
5
shows that the permanent magnet assemblies 22a are radiaIly located closer to
the first
axis 14 than are the permanent magnet assemblies 22 as shown in FIGURE 4.
Therefore, the number of nonmagnetic spacers 25 and permanent magnets 23
needed
are less.
The modular construction of the permanent magnet assemblies 22 permits the
manufacture of numerous rotary magnet units 20 having permanent magnet
assemblies 22 located at various radial distances about disks 28. This
manufacture
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can be done without the need to retool for making disks 28 of various sizes.
This
represents a tremendous cost savings over known rotary magnet units.
. FIGURE 6 shows a cross section of the permanent magnet assemblies 22.
Each permanent magnet 23 has a mating surface 29 that extends at an angle
outward
. 5 from the outer surface of the permanent magnet 23. Each non-magnetic
spacer 25
includes a mating surface 31 that extends at an angle inward from the outer
surface of
the non-magnetic spacer 25. The angles of the mating surfaces 29, 31
substantially
match so that the two surfaces align when the permanent magnetic assembly 22
is
assembled. The mating surfaces 29 and 31 are suitably rough, non-machined
surfaces.
Advantageously, the permanent magnets 23 and non-magnetic spacers 25 are
suitably
formed by being pressed in a mold of a desired shape, such as the shapes of
the non-
limiting examples discussed above, and then sintered. The permanent magnets 23
are
then magnetized in a known manner. The permanent magnets 23 are arranged about
the disk 28 at a radial distance as desired for a particular application. The
mating
surfaces 31 of the non-magnetic spacers 25 are inserted in an interleaved
manner
between the permanent magnets 23 such that the mating surfaces 31 abut against
the
mating surfaces 29. When the non-magnetic spacers 25 are attached to the disk
28,
such as with the bolts 27, the non-magnetic spacers 25 hold down the adjacent
permanent magnets 23 to the disk 28.
The rotary electroconductive unit 24 includes a disk 40 having a radius R2. It
is desirable that the disk 40 have high strength characteristics and be
lightweight. The
disk 40 is suitably made from aluminum or from stainless steel, but is
preferably made
of a composite material, such as RytexTM. In one exemplary embodiment shown in
FIGURE 11, given by way of a non-limiting example, the radius R2 is
approximately 7.5 inches, and the disk 40 has a thickness T2 of approximately
'/4 inch.
It will be appreciated that it is not necessary that the disk 40 have these
dimensions
but, rather, may have any thickness as desired for a particular application.
Further, it
will be appreciated that any radius is acceptable that provides sufficient
clearance
between the permanent magnets 22 and the conductor assembly 26, as will be
discussed more fully below.
As can be seen in FIGURES 2 and 3, the disk 40 extends outward and
includes U-shaped flanges 21 at its circumference that extend over and around
the
rotary magnet unit 20. The composite conductor assembly 26 on the disk 40
consists
of first, second, and third conductors 42, 44, and 46. The conductors 42, 44,
and 46
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are bonded within the U-shaped flange on the disk 40 on the front, top, and
rear sides
of the rotary magnet unit 20.
FIGURE 7 shows an alternate embodiment for a conductor assembly 26' that
can be used with the permanent magnet coupler 10. An arrangement similar to
the
conductor assembly 26' can replace one or all of the conductors 42, 44 or 46.
The
conductor assembly 26' includes modular conductor subassemblies 33 and 35. The
subassemblies alternate between arcuate-wedge-shaped modular conductor
subassemblies 33 and truncated disk-shaped modular conductor subassemblies 35.
The modular conductive subassemblies 33 and 35 are shaped and are fitted
together in
much the same way as the permanent magnets 23 and the non-magnetic spacers 25
described above. The modular conductor subassemblies 33 and 35 are made from a
composite material. The composite material includes a conductor, and
preferably
includes copper. The composite material also preferably includes a
semiconductor,
such as silicon, to raise the resistance of the conductor assembly 26'. A
suitable
composite that includes copper and silicon is GlidCop~, available from SCM
Metal
Products, Inc. of Research Triangle Park, North Carolina. The amounts of
copper
and silicon can be adjusted to adjust the resistance of the conductor assembly
26' as
desired. Increasing the resistance of the conductor assembly 26' is desired to
increase
the breakdown slip and also increase the starting torque.
FIGURE 8 shows a graph of torque versus slip speed for the present
invention. The curve A of torque versus slip speed for prior art permanent
magnet
couplers as shown in FIGURE 1 has been reproduced in FIGURE 8. Curve B shows
torque versus slip speed for the present invention when a first amount of
resistance is
added to the conductor assembly 26. As is known, breakdown torque occurs at a
breakdown slip (sb) that is determined according to the relationship:
R (1)
X
where R is the resistance of the conductor assembly 26 and X is the inductive
reactance of the conductor assembly 26 at standstill. Because the value of
breakdown
torque is a constant for a given permanent magnet coupler, it will be
appreciated that
increasing the resistance R of the conductor assembly 26 increases the
breakdown slip
sb as shown in curve B of FIGURE 8. It will be appreciated that the breakdown
slip sb as shown in curve B occurs at a higher slip speed, that is closer to
standstill,
than in the prior art. Curve C shows that the resistance R can be adjusted
such that
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can be done without the need to
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breakdown torque corresponds to a breakdown slip sb having a value of one.
That is,
breakdown torque is generated at standstill.
. It will be appreciated that increasing the breakdown slip and increasing the
starting torque also increase the steady state operating slip. However, the
use of a
composite material, such as GlidCop~, allows the conductor assembly 26 to
withstand additional heat generated from increased slip. For example, GlidCop~
having 90% copper by volume and 10% ceramic silicon by volume can withstand
temperatures up to 1,800°F without any appreciable creep. Thus, the
present
invention can provide increased electromagnetic torque and withstand increased
slip
without warping or failure of the conductor assembly 26.
As shown in FIGURE 9, the modular conductor subassemblies 33 and 35
suitably have ferrous backings 33' and 35'. The ferrous backings 33' and 35'
are
suitably substantially pure iron, such as A-131 electrolytic iron available
from SCM
Metal Products, Inc., of Research Triangle Park, North Carolina. The ferrous
backings 33' and 35' increase induction, and make up for induction losses of
the
copper used in the modular conductor subassemblies, as is known. However, in
the
presently preferred embodiment that uses a backing of substantially pure A-131
electrolytic iron, the resultant induction can be increased by a factor of
about 1000
over permanent magnet couplers that include copper conductors without a
backing of
substantially pure iron. The iron of the presently preferred embodiment is
pressed
iron powder that has a nominal mesh of less than 44p.m, and typically contains
70%
by weight of particles less than 20~m. The particles in the preferred iron
powder
have an irregular, dendritic (fern-like) shape resulting in a high specific
surface area.
A suitable binder, such as Silver epoxy from MasterBond or GenymerT'~'
bonding agent, is used to assemble all the magnet and conductor components.
This
epoxy increases the conductor components efFlciency at developing eddy
currents in a
composite layered assembly. As an alternative, the magnet pieces would be
injection
molded into one component. For example, the magnet holders can be injected
around
the magnets as one part.
FIGURE 10 shows another conductor assembly 26' that has a larger radius
. than the conductor assembly of FIGURE 7 because a greater number of modular
conductor subassemblies 33 and 35 are utilized and because the modular
conductor
subassemblies 33 and 35 are approximately of the same size. While the modular
conductor subassemblies 33 and 35 in FIGURES 7 and 10 are approximately in
same
size, modular conductor subassemblies 33 slightly differ in configuration to
account
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far the less dramatic curvature between adjacent subassemblies, causing the
truncated
wedge-shape in FIGURE 7 to become a substantially I-beam shape with rounded
corners or chamfered edges in FIGURE 10. Other configurations can be provided
so
as to properly space the subassemblies about the circumference of the disk 40.
The
magnitude of the radius of the conductor assembly could also be adjusted by
varying
the size of the modular conductor subassemblies 33 and 35.
In the following embodiments that are given by way of non-limiting examples,
it will be appreciated that many of the details of construction and operation
are as
described above. Accordingly, these details are not repeated. It will fizrther
be
appreciated that details regarding material selection in the following non-
limiting
embodiments are as described above and are also not repeated.
FIGURE 11 shows an alternate embodiment of a permanent magnet
coupler 10a. In contrast to the previous embodiment, the rotary magnet unit
20a of
the permanent magnet coupler l0a extends outside of and around the rotary
electroconductive unit 24a.
The rotary magnet unit 20a also includes a magnet mount assembly 30. The
magnet mount assembly 30 includes a mount arm 32 attached to the disk 28a,
extending parallel to the first axis 14, and orthogonal to the disk 28a. The
mount
arm 32 defines a hoop that extends along the outer circumference of the disk
28a and
has an inner diameter of 2R1. The mount arm 32 is suitably a high-strength,
lightweight material, such as a composite material. A suitable composite
material is a
fiber-reinforced thermoset composite material such as Black-Amalgon~,
available
from Amalga Composites, Inc., of Milwaukee, Wisconsin. In the exemplary
embodiments, given by way of non-limiting example, in which the radius R1
is 8 inches and the hoop 32 has an inner diameter of 16 inches, a suitable
mount
arm 32 is the model BA1600-B, made of Black-Amalgon~, available from Amalga
Composites, Inc. The mount arm 32 is suitably attached to the disk 28 in any
number
of methods well known in the art, such as with epoxy resin.
The permanent magnet assemblies 22a in FIGURE 11 are each formed by
three magnets 34, 36, and 38 and corresponding non-magnetic spacers (not
shown).
An array of the magnet assemblies 22a extends around the circumference of the
disk 28a and the mount arm 32. The magnets 34, 36, and 38 are arranged in
substantially a U-shape such that the opening of the U-shape is oriented to
face
toward the second shaft 16. In the present embodiment, the first magnet 34 is
bonded
in a known manner, such as with epoxy, to the mount arm 32 such that the first
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magnet 34 is substantially normal to the first axis 14. The second magnet 36
abuts the
first magnet 34, extends orthogonally thereto, and is bonded in a known
manner, such
as with epoxy, along the length of the mount arm 32 such that the second
magnet 36
extends substantially parallel to the first axis 14. The third magnet 38 abuts
the
second magnet 36, extends orthogonally thereto, and is bonded in a known
manner,
such as with epoxy, to the end of the mount arm 32. The third magnet 38
extends
substantially parallel to the first magnet 34.
The conductor assembly 26a in FIGURE 11 is formed by three conductor
plates 42, 44, and 46. The conductor plates 42, 44, and 46 are bonded to the
disk 40
in a U-shaped configuration. The first and third conductor plates 42 and 46
are
bonded to the sides of the disk 40 and are oriented parallel with the first
and third
magnets 34 and 38. The first and third conductor plates 42 and 46 extend
beyond the
ends of the first and third magnets 34 and 38 toward the second shaft i6. This
permits the first and third conductor plates 42 and 46 to be placed in
magnetic
1 S communication with the lines of magnetic flux that extend beyond the end
of the first
and third magnets 34 and 38. The second conductor plate 44 is bonded to the
end of
the disk 40 and is oriented sinularly to the second magnet 22. The second
conductor
plate 44 can be provided as a hoop because of its circumferential mounting.
The first,
second, and third magnets 34, 36, and 38 and the first, second, and third
conductor
plates 42, 44, and 46 are separated by an air gap of up to '/2 inch in the non-
limiting
example of the exemplary embodiment described above. An air gap on the order
of
%z inch allows misalignment between the first shaft 12 and the second shaft
16.
The orientation of the first and third magnets 36 and 38 with respect to each
other may be adjusted to provide a desired gap with respect to the conductor
plates 42, 44, and 46. Therefore, it will be appreciated that the first and
second
magnets 34 and 36 need not be normal to each other. Likewise, the second and
third
magnets 36 and 38 need not be normal to each other. Rather, they may be
adjusted
about a normal orientation as desired for a given application. In the same
manner, the
orientation of the conductor plates 42, 44, and 46 can be adjusted for a given
application.
Each magnet 34, 36, and 38 of the U-shaped permanent magnet assembly 22a
faces a corresponding plate 42, 44, and 46 of the U-shaped conductor assembly
26a.
The addition of the second magnet 36 increases the magnetic field generated by
the
rotary magnet unit 20 beyond that capable of being generated in known
permanent
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magnet couplers. The increased magnetic field contributes to an increased
electromagnetic torque.
The addition of the second conductor plate 44 increases the surface area of
conductors that magnetically communicate with lines of magnetic flux from
permanent magnets beyond those currently known in the art. By increasing the
amount of conductor that cuts through the lines of magnetic flux, an increased
current
is generated within the conductor. This in turn increases the electromagnetic
force
attracting the conductor to the permanent magnet. Thus, because force is
increased,
torque is increased. Thus, the embodiment of FIGURE 11 increases the amount of
electromagnetic torque available to be transferred between the first shaft 12
and the
second shaft 16.
FIGURE 11A shows an alternate arrangement of a rotary magnet unit 20b and
a rotary electroconductive unit 24b of a permanent magnet coupler lOh. A disk
28b is
sinular to the disk 28a (FIGURE 11) and is coupled to the first shaft (not
shown) in a
manner similar to the disk 28a. A plurality of U-shaped permanent magnet
assemblies 22b are receivably mounted within the disk 28b. Each of the U-
shaped
permanent magnet assemblies 22b includes first, second, and third permanent
magnets 35, 37, and 39. The permanent magnets 35, 37, and 39 are oriented to
each
other as the magnets 34, 36, and 3 8 (FIGURE 11 ) are oriented to each other.
However, the U-shaped magnet assemblies are shaped so that the open side of
the
"U" extends parallel to the first axis 14, instead of normal to the first axis
as was
shown in FIGURE 11.
The rotary electroconductor unit 24b includes a disk 40b that is similar to
the
disk 40a (FIGURE 11) and is coupled to a second shaft {not shown) in a manner
similar to the disk 40a. The opening of each of the U-shaped permanent magnet
assemblies 22b is oriented to generally face toward the disk 40b. The disk 40b
has an
extension 41 that forms a hoop that is oriented toward and extends into the
openings
of the U-shaped permanent magnet assemblies 22b. The conductor assembly 26b is
attached to the extension 41 and the side of the disk 40b facing the first
disk 28b. The
conductor assembly 26b includes conductor plates 43, 43a, 45, 47, and 47a. The
conductor plates 43a and 47a extend on the outside and inside, respectively,
of the
extension 4I . The conductor plate 45 extends along the distal end of the
extension 41
and extends substantially parallel to the conductor plates 43a and 47a. The
conductor
plates 43 and 47 extend along the inside and outside circumference of the
extension 41. The conductor plates 43a, 45, and 47a are suitably disks, such
as the
. .
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conductor plates 42 and 46 {FIGURE 11 ). The conductor plates 43 and 47 are
suitably hoops, such as the conductor plate 44 (FIGURE 11). The operation and
benefits of the coupler 11 is similar to the coupler 10 in FIGURE 11. However,
in
addition to the benefits of the coupler 10 in FIGURE 11, the coupler 11 of
FIGURE 11 A includes additional magnetic field contributed by the distal ends
of the
magnets 35 and 39, and increased current from the conductor plates 43a and
47a.
FIGURE 11B shows another alternate arrangement of a permanent magnet
coupler lOc having a rotary magnet unit 20c and a rotary electroconductive
unit 24c.
As with the previous embodiments, the permanent magnet coupler lOc has first
and
second disks 28c and 40c. The first and second disks 28c and 40c are shaped
substantially the same as the disks 28a and 40a in FIGURE 11. However, the
magnets and conductors in this embodiment are located in different locations.
In the
embodiment shown in FIGURE 11B, the first and second disks 28c and 40c each
include magnets and conductors. The first disk 28c includes a first L-shaped
conductor 42a that extends at right angle along a portion of the inside of the
U-shaped distal end of the disk 28c and along the right side of the disk 28c.
The
second and third conductors 44a and 46a are attached to the second disk 40c
and
extend along the outer and right distal end surfaces, respectively. Each of a
plurality
of permanent magnet assemblies 22c includes a first permanent magnet 34a
mounted
on the disk 40c opposite the conductor 42a, and second and third permanent
magnets 36a and 38a mounted on the disk 28c opposite the conductors 44a, 46a,
respectively. When one of the disks 28c or 40c is rotated, the first magnets
34a
become electromagnetically coupled to the first conductor 42a, and the second
and
third magnets 36a and 38a become electromagnetically coupled to the second
conductor 44a and the third conductor 46a, respectively.
FIGURE 12 shows a permanent magnet coupler 50 according to another
embodiment of the present invention. Many of the details of the construction
of the
coupler 50 are similar to that of the coupler 10 shown in FIGURE 1 l, and will
not be
discussed below. The coupler 50 includes an array of L-shaped permanent magnet
assemblies 52 and an L-shaped conductor assembly 54. The L-shaped permanent
magnet assemblies 52 each include a first permanent magnet 56 and a second
permanent magnet 58. The magnets 56 and 58 of the L-shaped permanent magnet
assembly 52 correspond to the magnets 36 and 38 of the U-shaped permanent
magnet
assembly 22. The L-shaped conductor assembly 54 includes a first conductor 60
and
a second conductor 62. The first and second conductors 60 and 62 of the L-
shaped
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conductor assembly 54 correspond to the conductors 44 and 46 of the U-shaped
conductor assembly 26.
The domains of the magnets 56 and 58 are suitably aligned by known
techniques to balance electromagnetic forces such that no net lateral torque
is
generated. The remainder of the details of the construction of the coupler 50
are
similar to those of the previously described permanent magnet couplers 10.
FIGURE 12A shows an alternate arrangement of a rotary magnet unit 20e and
a rotary electroconductive unit 24e of a permanent magnet coupler 50a. A disk
28e is
similar to the disk 28d (FIGURE 12) and is coupled to the first shaft (not
shown) in a
manner similar to the disk 28d. A disk 40e is similar to the disk 40d (FIGURE
12)
and is coupled to the second shaft (not shown) in a manner similar to the disk
40d. A
first plurality of L-shaped permanent magnet assemblies 52a are mounted on the
disk 28e. Each of the L-shaped permanent magnet assemblies 52a includes first
and
second permanent magnets 56a and 58a. A second plurality of L-shaped permanent
magnet assemblies 52b are mounted on the disk 40e. Each of the L-shaped
permanent magnet assemblies 52b includes third and fourth permanent magnets
56b
and 58b.
The disk 40e includes a first L-shaped conductor assembly 54a that includes a
first conductor 60a, that is suitably a copper hoop, and a second conductor
62a, that
is suitably a copper disk. The disk 28e includes a second L-shaped conductor
assembly 54b that includes a third conductor 60b, thus is suitably a copper
hoop, and
a fourth conductor 62b, that is suitably a copper disk. When one of the disks
28e
or 40e is rotated, the first plurality of L-shaped permanent magnet assemblies
52a
become electromagnetically coupled to the first L-shaped conductor assembly
54a,
and the second plurality of L-shaped permanent magnet assemblies 52b become
eiectromagnetically coupled to the second L-shaped conductor assembly 54b.
FIGURE 13 shows a permanent magnet coupler 70 according to another
embodiment of the present invention. The permanent magnet coupler 70 includes
a
disk 28f, mount arm 32, and disk 40f that are similar to the disk 28a, mount
arm 32,
and disk 40a of FIGURE 1 i. The permanent magnet coupler 70 includes an array
of
permanent magnets 72 located along the inner side of the mount arm 32 and a
conductor 74 on the end of the disk 40f. The remainder of the construction of
the
coupler 70 is similar to that of the permanent magnet coupler 10 and the
permanent
magnet coupler 50. Because the magnets 72 are located at the distance R1 from
the
second shaft 16, and the conductor 74 is located at the shorter distance R2
from the
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second shaft 16, the electromagnetic force generated by the magnet 72 has a
moment
arm greater than that in known couplers. Because the moment arm is longer, the
coupler 70 generates an electromagnetic torque that is greater than that
generated by
known couplers,
FIGURE 13A shows an alternate arrangement of a permanent magnet
coupler 70a. The coupler 70a includes a disk 28g that is sinular to the disk
28f
(FIGURE 13) and is similarly attached to the first shaft (not shown) as the
disk 28f.
The disk 28g includes a right-angle triangular mount arm 32a attached to its
distal end
and arranged so that the hypotenuse 76 of the mount arm extends at a
45° angle to
the plane of the disk 28g. The coupler 70a also includes a disk 40g that is
similar to
the disk 40f (FIGURE 13) and is similarly attached to the second shaft (not
shown).
A second right-angle triangular mount arm 75 is attached to the end of the
disk 40g
and is arranged so that its hypotenuse 77 is 45° to the plane of the
disk 40g and so
that the hypotenuse 77 of the second right-angle triangular mount arm 75 is
located
adjacent and along the hypotenuse 76 of the right-angle triangular mount arm
32a.
The disk 28g includes a first array of permanent magnets 72a located on the
outer end
of the hypotenuse 76, and the disk 40g includes a second array of permanent
magnets 72b located on the inner end of the hypotenuse 77. The disk 40g
includes a
first conductor 74a that is substantially aligned within the right-angle
triangular mount
arm 75 across from the first permanent magnets 72a, and the right-angle
triangular
mount arm 32a includes a second conductor 74b that is substantially aligned
within
the disk 28g across from the second permanent magnets 72b. The alignment
between
the magnets 72a and the conductor 74b, and the alignment between the magnets
72b
and the conductor 74a, is suitably within 2° and is preferably within
5° to
accommodate as large a gap as practicable between the permanent magnets 72a
and
the conductor 74a, and between the permanent magnets 72b and the conductor
74b,
respectively.
Mounting the magnets 72a at an angle relative to the magnets 72
(FIGURE 13) further increases the moment arm and therefore further increases
the
electromagnetic torque over the amount of torque produced by the embodiment in
FIGURE 13. The addition of the second array of magnets 72b and the second
conductor 74b further increases the magnetic field, and thus further increases
the
electromagnetic torque.
FIGURE 13B shows an alternate arrangement of a permanent magnet
coupler 70b. The coupler 70b is similar to the coupler 70a (FIGURE 13A) except
for
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orientation of the magnets and conductor mounted on the disks. A disk 28h
includes
first and second triangular mount arms 78, 79 that extend toward the disk 40g
and
upon which are mounted the permanent magnets 72a and the conductor 74b with an
angle a therebetween. A disk 40h includes a triangular mount arm 75a that
extends
toward and between the first and second triangular mount arms 78, 79, and that
is
arranged for mounting the permanent magnets 72b and the conductor 74a with an
angle ~i therebetween. As shown in the non-limiting example of FIGURE 13B, the
angle a is suitably about 90°, and an angle (3 is suitably about
270°. It will be
appreciated that the angle a and the angle p are not limited to angles of
about 90°
and 270°, respectively. Rather, the angle a and angle (3 may have value
according to
the relationship:
a + [3 ~ 3 60° (2)
It will be appreciated that when a ~ ~3 ~ 180°, the coupler 70b is
similar to the
coupler 70a (FIGURE 13A).
FIGURE 13C shows another alternate arrangement of a permanent magnet
coupler 70c. The coupler 70c is an example of an alternate embodiment of the
coupler 70a (FIGURE 13A) wherein a ~ ~i ~ 180°. In the coupler 70c, a
disk 28j is
arranged to receivably mount the magnets 72a and the conductor 74b, and a disk
40j
is arranged to receivably mount the magnets 72b and the conductor 74a.
However,
the disks 28j and 40j are arranged such that the magnets 72a and 72b and the
conductors 74b and 74a are oriented along opposing faces of the disks 28j and
40j. It
will be appreciated that, in the example shown in FIGURE 13C, the magnets 72a
and 72b and the conductors 74a and 74b are aligned substantially normal to the
first
and second shafts (not shown).
FIGURE 14 shows a permanent magnet coupler 80 according to another
embodiment of the present invention. The permanent magnet coupler 80 includes
an
array of permanent magnets 82 and a U-shaped conductor assembly 84. The
permanent magnets 82 are bonded to the mount arm 32 as discussed above. If
desired, an additional permanent magnet 82a may be attached to the end of the
permanent magnets 82 to increase the magnetic field adjacent the end of the
permanent magnets 82. The U-shaped conductor assembly 84 includes first,
second,
and third conductors 86, 88, and 90. The conductors 86, 88, and 90 are similar
to the
first, second, and third conductors 42, 44, and 46 of the permanent magnet
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coupler l0a {FIGURE 11). Thus, the conductors 86, 88, and 90 are suitably
copper
plates, as described above.
The conductor 86 is bonded to the disk 40k, as described above. The plate 90
is similarly bonded to a second disk 91 which is mounted on the second arms 16
parallel to the disk 40k. The second disk 91 is similar to the disk 40a
(FIGURE 11)
and is attached to the second shaft 16 similarly to the disk 40k. The disks
40k and 91
are spaced apart along the second shaft 16 such that the second conductor 88
may be
placed between the first conductor 86 and the third conductor 90. The second
conductor 88 is bonded to the first and third conductors 86 and 90 in a known
manner. The disks 40k and 91 are physically coupled with a plurality of non-
magnetic
spacers 92. Coupling the disks 40k and 91 with the non-magnetic spacers 92 is
considered to be well-known and will not be discussed in detail.
It will be appreciated that each face of the magnet 82 is in magnetic
communication with a corresponding conductor 86, 88, and 90. Thus, the
permanent
magnet coupler 80 achieves the gains in increased electromagnetic torque over
known
couplers in a similar manner to the permanent magnet coupler l0a (FIGURE 11).
FIGURES 1 S and 16 show a permanent magnet coupler 110 according to
another embodiment of the present invention. The permanent coupler 110
includes a
magnet rotor shaft 112 (FIGURE 16) having a magnet rotor shaft axis 114 and a
conductor rotor shaft 116 having a conductor rotor shaft axis 118 that is
substantially
aligned with the magnet rotor shaft axis 114. A magnet rotor assembly 120
(best
shown in FIGURE 17) is mounted to rotate with the magnet rotor shaft 112. The
magnet rotor assembly 120 includes an array of permanent magnet assemblies 122
that form two spaced-apart hoops 125 of permanent magnet assemblies. A
conductor
rotor assembly 124 (FIGURE 21) is mounted to rotate with the conductor rotor
shaft 116. The conductor rotor assembly 124 includes a plurality of conductor
rotor
components 126 that are joined together to form those spaced-apart hoops 127
of the
conductor rotor components 126. The hoops 127 of the conductor rotor
components 126 and the hoops 125 of the permanent magnet assemblies 122 are
intertwined and spaced apart from each other. Rotation of the magnet rotor
shaft 112
causes rotation of the conductor rotor shaft 116 due to electromagnetic
coupling
between the magnet rotor assembly 120 and the conductor rotor assembly 124.
- Turning now to FIGURE 18, the magnet rotor shaft 112 is suitably a motor
shaft, and the conductor rotor shaft 116 (FIGURE 21 ) is suitably a load
shaft.
However, it is not necessary that the magnet rotor shaft 112 be a motor shaft
and the
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conductor rotor shaft 116 be a load shaft. The magnet rotor shaft 112 is also
suitably
a load shaft, and the conductor rotor shaft 116 is also suitably a motor
shaft. The
magnet rotor shaft 112 and the conductor rotor shaft 116 are separated from
each
other. The magnet rotor shaft axis I14 and the conductor rotor shaft axis 118
are
substantially aligned with each other. Longitudinal and radial misalignment
may be
tolerated between the magnet rotor shaft axis 114 and the conductor rotor
shaft
axis I18, depending upon the gap between the magnet rotor assembly 120 and the
conductor rotor assembly 124, as will be discussed more fully below.
The magnet rotor assembly 120 includes a magnet rotor disk 128
(FIGURE 18). It is desirable that the magnet rotor disk 128 have high strength
characteristics yet be lightweight. Therefore, the magnet rotor disk 128 is
preferably
made from a composite material, such as RytexT"~. However, the magnet rotor
disk 128 is suitably made of aluminum or stainless steel. In one exemplary
embodiment, given by way of a non-limiting example, the magnet rotor disk 128
has a
radius Rl of approximately 15 inches and a suitable thickness T1 of
approximately 1/4
inch. It will be appreciated that it is not necessary that the magnet rotor
disk 128
have these dimensions but, rather, may have any radius and thickness as
desired for a
particular application. The magnet rotor disk 128 includes a plurality of
mounting
holes 130. The magnet rotor assembly 120 also includes a magnet rotor plate
132.
The magnet rotor plate 132 includes a plurality of mounting holes 134. The
magnet
rotor plate is also preferably made from a composite material, such as
RytexTM, and is
also suitably made from aluminum or stainless steel. The magnet rotor assembly
120
also includes a B-lock 136. The B-lock 136 is attached to the magnet rotor
shaft 112
in a known manner, and is coupled to the magnet rotor plate 132 in a well
known
manner. The magnet rotor plate 132 is coupled to the magnet rotor disk 128
bolts
(not shown) received through the mounting holes 130 of the magnet rotor disk
128
and the mounting holes 134 of the magnet rotor plate 132. The magnet rotor
assembly 120 is suitably housed within composite tubing, such as carbon-
graphite
high-speed tubing, as described above.
Each permanent magnet assembly 122 includes a permanent magnet 138
(FIGURE 19). FIGURE 19 shows a permanent magnet 13 8. The permanent
magnets 138 are suitably rare-earth-type magnets, such as lanthanides like
samarium,
cobalt, and neodymium iron boron, as are well known in the art. Neodymium iron
boron magnets are presently preferred because they have a high flux density
and
because their domains can be preoriented before final magnetization. As shown
in
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FIGURE 19, the side of the permanent magnet 138 is preferably sinusoidally
curved.
The curve on the side of the permanent magnet 138 is for stress relief. The
shape of
the permanent magnet 138 is preferably different on each side.
The magnet rotor assembly 120 includes a plurality of magnet holders 140
- 5 {FIGURE 17). FIGURE 20 shows a single magnet holder 140. Two magnet
holders 140 are used on opposite sides of the permanent magnet to hold the
magnet in
the magnet rotor subassembly. The magnet holder 140 is a high-strength, high
temperature SAE standard gear-grade thermoplastic with fibers integral to the
injection material. The magnet holder 140 is preferably made from
FiberstranTM,
available from DSM Engineering Plastics, Evansville, Indiana. The magnet
holder 140 is suitably made from a polyurethane such as Isoplast lOILGF40NAT,
manufactured by Dow Plastics and available from N.A. Hanna Resin Distribution.
The magnet holder 140 shown in FIGURE 20 includes a cavity 142 adapted to
receive the permanent magnet 138. The magnet holders 140 include tabs 139 for
interlocking adjacent magnet holders.
To form the magnet holder 140, the permanent magnet 138 is placed in a
thermoplastic injection molder immediately after sintering is finished.
Material as
described above is injected around the magnet, forming two of the magnet
holders 140 on opposite sides of the permanent magnet 138. Alternatively, two
magnet holders 140 can be injected to net shape, as individual half sections,
and can
then be glued together over the symmetrical permanent magnet 138.
The magnet holders 140 are attached to the magnet rotor disk 128 in a known
manner, such as with bolts that extend through the mounting holes 130 of the
magnet
rotor disk 128. It will appreciated that the size of the magnet rotor assembly
120 can
be varied simply by sizing the diameter D1 of the magnet rotor disk 128 as
desired and
then mounting the desired number of permanent magnet assemblies 122 about the
magnet rotor disk I28 as described above. The modular construction of the
permanent magnet assemblies 122 permits the manufacture of numerous magnet
rotor
assemblies 120 having permanent magnet assemblies I22 located at various
radial
distances about the magnet rotor disks 128. This flexible manufacturing of
making
magnet rotor assemblies 120 of various sizes can be performed without
retooling.
This represents a tremendous cost savings over known magnet rotor assemblies.
FIGURES 21 and 22 show a conductor rotor assembly 124 for the permanent
magnet coupling 110. The conductor rotor assembly 124 includes a conductor
rotor
3 5 disk 144 {best shown in FIGURE 22). The conductor rotor disk 144 is
constructed
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from the same materials and in the same manner as the magnet rotor disk 128,
as
described above. In addition, the conductor rotor disk 144 includes a
plurality of air
cooling holes 146. The conductor rotor assembly 124 includes a conductor rotor
plate 148 and a B-lock 150 that are constructed as described above for the
magnet
rotor plate 132 and B-lock 136. The conductor rotor disk 144 is attached to
the
conductor rotor shaft 116 with the conductor rotor plate 148 and the B-lock
150 in
the same manner as the magnet rotor disk 128 is coupled to the magnet rotor
shaft 112, as described above. In one exemplary embodiment, the conductor
rotor
disk 144 has a diameter D2 of about 30 inches and a thickness T2 of about 1/4
inch.
The conductor rotor assembly 124 is suitably housed within composite tubing,
such as
carbon-graphite high-speed tubing, as described above.
The conductor rotor assembly 124 includes a plurality of conductor rotor
components 126. FIGURE 23 shows a single conductor rotor component 126. The
conductor rotor component 126 is made from a suitable conductor, such as
copper,
iron, or steel. The conductor rotor component 126 is also suitably made from a
conductive ceramic material, like zinc oxide-type, in place of copper. The
conductor
rotor component 126 is also suitably made from iron cobalt for increased
magnetic
permeability. A suitable iron cobalt conductor is Hiperco 50, available from
Carpenter Technology of Reading, Pennsylvania. Copper coatings can be applied
to
iron cobalt, steel, or iron if the surface is raised or grooved. The copper
can be cast
onto a rough surface that provides a gripping system to hold the copper
coating. The
conductor rotor component 126 is suitably coated with silver or gold, or a
combination of silver and gold for increased corrosion resistance and
conductivity.
The conductor rotor component 126 is preferably made from a composite
material that includes a conductor such as copper. The composite material also
preferably includes material that raises the electrical resistance of the
conductor rotor
component 126. A suitable composite material that includes copper and a
semiconductor is GlidCop~, available from SCM Metal Products, Inc. of Research
Triangle Park, North Carolina. GlidCop~ contains copper and aluminum oxide.
The
percentage of aluminum oxide content in the copper is preferably in a range of
about
.l% to 1%. A content of .1% aluminum oxide in copper yields a conductivity
that is
about 90% the conductivity of copper, and a 1% aluminum oxide content in
copper
yields a conductivity that is about 78% the conductivity of copper. The
amounts of
copper and aluminum oxide can be adjusted to adjust the resistance of the
conductor
rotor component 126 as desired. Increasing the resistance of the conductor
rotor
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component 126 above that of copper is desired to increase the breakdown slip
and
also increase the starting torque.
As shown in FIGURES 21 and 22, the conductor rotor components 126 are
arranged in a substantially circular ring having a diameter of about the
diameter D2 of
the conductor rotor disk 144. The rings of conductor rotor components 126 are
layered axially. If desired, alternating layers of rings of conductor rotor
components 126 can include conductor rotor components 126 made of iron, such
as a
substantially pure iron like A-131 electrolytic iron available from SCM Metal
Products, Inc. of Research Triangle Park, North Carolina. The iron of the
presently
preferred embodiment is pressed iron powder that has a nominal mesh of -325
(<44p,m), and typically contains 70% by weight of particles less than 20p,m.
The
particles in the preferred iron powder have an irregular, dendritic {fern-
like) shape
resulting in a high specific surface area. The use of a ferrous conductor
rotor
component 126 increases induction, and makes up for induction losses of the
copper
used in other rings of conductor rotor components 126. According to the
present
invention, the use of substantially pure electrolytic iron can increase
induction by a
factor of about 1,000 times over permanent magnet couplers that include copper
conductors only with no substantially pure iron. In addition, every other
conductor
rotor component 126 within the same ring of conductor rotor components 126 can
be
a ferrous conductor rotor component 126, such as one made from substantially
pure
electrolytic iron, steel, or iron, to focus the flux field. Further, alternate
layers of rings
of the conductor rotor components 126 suitably overlap. Therefore, the
permanent
magnet assemblies 122 do not see a discontinuity in the conductor rotor
assembly 124
because of the overlap.
The conductor rotor components 126 each include a mounting hole 152
(FIGURE 23). Layers of rings of conductor rotor components 126 are aligned
such
that the mounting holes 152 are aligned with each other. The number of layers
of
rings of conductor rotor components 152 can be adjusted as desired for a
particular
application. The number of rings of conductor rotor components 126 determines
the
thickness of the conductor hoop 127 between the permanent magnets 138. More
- layers can be added in the axial direction to match increased powers of
permanent
magnets 138. The number of layers of rings of conductor rotor components 126,
as
- well as the thickness of each conductor rotor component 126 can be adjusted
as
desired to match strengths of permanent magnets 138. However, the thickness of
copper and steel are preferably about the same. When magnet power is
increased, the
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thickness, or number of layers, should be increased. The layers of rings of
conductor
rotor components 126 are spaced apart by spacers 154. Bolts or pins (not
shown)
extend through the mounting holder 152 and the spacers 154 to hold the arrays
of
rotor components 126 together. In a presently preferred embodiment, the
spacers 154 are made of any suitable material and have about a one-inch
diameter
with a length of about one and one-fourth inch. This length of the spacer 154
provides an air gap of about 1/8 inch between each permanent magnet 138 and
each
conductor rotor component 136. If it is desired to provide attachment of
adjacent
rotor components 126 to each other, a conductor rotor components 126 can be
bolted
or riveted together about a pivot point 156 (FIGURE 23) on each conductor
rotor
component 126. However, bolts can be placed anywhere in the conductor rotor
component 126 or in a permanent magnet 138. Further, optional grooves 158 in
the
radial direction of rotation can provide up to about a 50% increase in surface
area as
seen by the permanent magnets 13 8.
FIGURE 24 shows another conductor rotor assembly 124a according to the
present invention. In the conductor rotor assembly 124 shown in FIGURE 24, the
mounting holes I52 are oriented inward toward the conductor rotor shaft 116.
FIGURE 25A shows an optional rotor assembly that can be made without the
use of a disk. The optional rotor assembly 158 may be either a magnet rotor
assembly
or a conductor rotor assembly. The rotor assembly 158 is made from a plurality
of
link assemblies 160. Details of the link assembly 160 are shown in FIGURE 25B.
Each link assembly 160 has a rounded male end 162 and a rounded female end
164.
The male end 162 includes a peg i66 and the female end 164 includes a cavity
168.
The peg 166 and the cavity 168 are shaped and sized such that the peg 166 is
received
within the cavity 168 for connecting link assemblies 160. As best seen in
FIGURE 25A, the female ends 164 are arranged to face radially outward and the
male
ends 162 are arranged to face radially inward toward a shaft such as the
magnet rotor
shaft 112 or the conductor rotor shaft 116. The male ends 162 may be coupled
to a
magnet rotor plate 132 or a conductor rotor plate 148 as desired. Further, the
number of rings of link assemblies 160 may be adjusted as desired to adjust
the size of
the rotor assembly 158. A permanent magnet assembly 122 or a conductor rotor
assembly 124 may be connected to the outwardly facing female ends 164 of the
rotor
assembly 158 as desired for a particular application.
FIGURE 26 shows a variable speed drive coupler 190 according to an
3 S alternate embodiment of the present invention. In the non-limiting example
shown, a
r , ,
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motor 192 is slidably mounted on a tray 193 for slidable movement
substantially
transverse with the axis 14 of the motor's shaft 12. Thus, the motor shaft 12
and the
motor 192 are mobile relative to the load shaft 16. A magnet rotor assembly
194 is
attached to the motor shaft 12 and is received within a conductor rotor
assembly 196
that is connected to the load shaft 16. The structure of the magnet rotor
assembly 194 and the conductor motor assembly is similar to the embodiments in
FIGURES 21-25.
The magnet rotor assembly 194 and the conductor rotor assembly 196 are
coupled by a magnetic eddy current drive only when the conductor rotor
assembly 196 is off center, because the conductor rotor assembly 196 is small
enough
that it can fit within the magnet rotor assembly without forming an eddy
current. The
axis of the motor shaft 12 and the axis of the load shaft 16 are substantially
parallel to
each other. The slidable tray 193 can be slid along an alignment channel the
distance
of the radial length of the magnets, or the motor can be mounted on an
elevated pivot
(not shown).
The slidable tray 193 or the elevated pivot acts to balance the motor 192 at
the center so that very little energy is needed to move the motor 192 and
magnet
rotor assembly 194 in and out of the conductor rotor assembly 196 field,
thereby
increasing or decreasing the speed of the load shaft 16. The load shaft 16
will be at
rest when the magnet rotor assembly 194 is moved to the center of the
conductor
rotor assembly 196. In this position, no eddy current is formed in the
conductor, so
no movement is initiated in the conductor rotor assembly. Thus, by moving the
motor 192 back and forth, the speed of the load shaft can be varied. In an
alternate
embodiment, the load shaft 16 could be moved instead of the motor shaft 12, or
both
could be moved relative to each other.
FIGURE 27 shows an alternate conductor rotor assembly 200 according to
another aspect of the present invention. In this non-limiting example, ten
conductor
rotor components 126a have been linked together and are further mounted to
rotor
units 170, which are placed substantially adjacent one another to form a
generally
circular pattern that may be suitably formed into a rotor. It will be
appreciated that
the use of these rotor units 170 will permit modular assembly of rotors. The
rotor
units 170 shown in this FIGURE 29 are of a substantially triangular shape, but
other
shapes may be used where suitable to permit modular assembly of a rotor.
FIGURE 28 shows a further alternative conductor rotor assembly according
to the present invention. In this non-limiting example, 20 conductor rotor
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components 126a are linked together and further mounted to an array of rotor
units 172, which are themselves connected to other rotor units 170. Rotor
units 172
are shown in the shape of irregular trapezoids, while rotor units 170 are the
substantially triangular shape of the previous FIGURE 27, but it will be
appreciated
that other shapes may be used where suitable to permit modular assembly of the
rotor.
The embodiment of FIGURE 28 gives yet another example of the changeability and
modular component structure of the rotor assemblies of the present invention.
FIGURE 29 shows a further alternative conductor rotor assembly according
to the present invention. In this non-limiting example, 30 conductor rotor
components 126 are linked together and further mounted to an array of rotor
units 172, which are in turn fastened to another array of rotor units 172
arranged to
form a smaller diameter, and they are in turn mounted to rotor units 170.
FIGURE 29
as well as the previous two figures, illustrates the modular assembly of
rotors that
forms an aspect of the present invention.
FIGURES 30 and 31 show an alternative magnet holder 180 capable of
retaining four permanent magnets 138 in the four cavities 182 of the magnet
holder.
While modularity of assembly of permanent magnet assemblies is served by using
a
suitable number of single magnet holders 140 as shown in FIGURE 20, it will be
appreciated that in some applications a multiple-magnet holder such as the
four-
magnet holder 180 of FIGURE 30 will grant a manufacturing advantage and
promote
ease of assembly. The four magnet holder 180 incorporates cavities 182 that
accept
four permanent magnets i38. The use of multiple magnet holders may include any
suitable numbers of magnets that may be assembled modularly.
Assembled hexagons or other suitable tessellations can be assembled into
rotors. A hexagon is a preferred embodiment. FIGURE 32 shows a hexagonal link
rotor assembly 210 that provides a modular assembly whereby the male side of a
hexagonal link 212 interconnects with the female side of adjacent hexagonal
links 212.
The joined hexagonal links 212 of the rotor assembly 210 forms a conductor
rotor or
a magnet rotor as desired. FIGURE 33 shows the female side of the hexagonal
link
and FIGURE 34 shows the male side of the hexagonal link. As can be seen, the
female sides of the hexagonal links include six recessed triangles 214, all
pointing
toward the center of the hexagonal link 212. In contrast, the male sides of
the
hexagonal links 212 includes six triangular-shaped protrusions 216. Two
recessed
triangles 214 are fitted over two triangular-shaped protrusions 216 of an
adjacent and
3 5 underlying hexagonal link 212. Two more recessed triangles 214, each from
two
.,
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more hexagonal links 212, fit over the other four triangular-shaped
protrusions 216.
The hexagonal links 212 can continue to be built in this manner so as to form
a
gridwork pattern of connected hexagonal links 212.
FIGURE 35 shows a magnet rotor 220 formed using the hexagonal link rotor
assembly 210 of FIGURE 32. As can be seen in the figure, the magnet rotor 220
includes two different types of magnet holders 222, 224 that extend around the
circumference of the hexagonal link rotor assembly 210 and which hold a
plurality of
magnets 13 8 therein. The arrangement within the magnet holders 222, 224 for
holding the magnets 138 are similar to the cavities and structure described
with
reference to FIGURES 30 and 31. The magnet holders 222, 224, however, instead
of
including mounting holes, include triangular connectors 226. The triangular
connectors 226 can be either protrusions or recesses, depending upon the
layout of
the hexagonal link rotor assembly 210 and the position of the magnet holders
222,
224. Alternatively, the connectors 226 can be located on both the top and
bottom
surfaces of the magnet holders 222, 224. For example, protrusions can be
located on
one side and recesses on the other.
As can be seen in FIGURE 36, the hexagonal pattern of the triangular
connectors 226 is slightly different for the two magnet holders 222, 224.
Specifically,
the triangular patterns are offset 30° relative to one another so that
adjacent magnet
holders 222, 224 can extend from different orientations of the recess
triangles 214 or
the triangular-shaped protrusions 216 of the hexagonal links 212. In addition,
the
central axis for the triangular connectors 226 of the magnet holder 222 is
slightly
offset relative to the central axis of the triangular connectors 226 of the
magnet
holder 224 so that the magnets 138 within the magnet holders are aligned the
same
radial distance away from the central axis of the magnet rotor 220.
FIGURE 37 shows an alternate arrangement for a magnet rotor 230 formed
from the hexagonal link rotor assembly 210. The magnet rotor 230 includes two
different magnet holders 232, 234 that are alternated around the perimeter of
the
magnet rotor. The first of the magnet holders 232 holds four magnets, and has
sides
which are substantially parallel to each other and a bottom that includes two
or four
. triangular connectors 236. The second magnet holder 234 is substantially
triangularly-shaped, and includes six triangular connectors 236 for connecting
to the
recessed triangles 216 or triangular-shaped protrusions 216 of the hexagonal
links 212
within the hexagonal link rotor assembly 210.
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It can be understood that a variety of different magnet holders having a
variety
of different patterns of triangular connectors 236 can be provided for making
a variety
of different magnet rotors, or conductor rotors, for use in the present
invention.
These additional embodiments can include additional hexagonal links 212 so as
to
form a larger hexagonal link rotor assembly 210 and to extend outward the
magnet
holders 232, 234, or 222, 224.
FIGURE 38 shows a conductor rotor 240 formed using the hexagonal Link
rotor assembly 210 of FIGURE 32. The conductor rotor 240 includes an array of
alternating conductors 242, 244 that extend around the circumference of the
hexagonal link rotor assembly 210. The conductors 242, 244 are shaped similar
to
the magnet holders 222, 224 of FIGURES 35 and 36, and are arranged in the same
manner about the hexagonal link rotor assembly 210.
FIGURE 39 shows another hexagonal link 250 that is used to make a rotor
assembly 252 (FIGURE 49), such as a conductor rotor assembly or a magnet rotor
assembly (FIGURE 49), of the hexagonal links. As shown in FIGURE 39, the
hexagonal link 250 includes a cylindrical peg 254 projecting from one side of
the
hexagonal link. The hexagonal link 250 also includes rounded concave corners
256
that are arranged to receive the central pegs of other links. As can be seen
in
FIGURE 39, the male side of the hexagonal link 250 includes protrusions 258,
whereas the female side of the hexagonal link includes recesses 260 (FIGURE
40).
As can be seen in FIGURE 41, the hexagonal links 250 fit together in much the
same
way as the hexagonal links 212 described with reference to FIGURE 32. However,
in
addition to the recesses and protrusions 258, 260, the peg 254 provides
additional
connection support for adjacent interlinked hexagonal links 250. As can best
be seen
in FIGURE 42, the hexagonal Iinks 250 include rounded, concave shoulders 262
through which the peg 254 extends. A snap ring 264 fits over the end of the
peg and
against the shoulders 262 {FIGURE 44). The final assembled snap ring 265 is
shown
in place in FIGURE 46.
Two types of magnet holders 240, 242 respectively shown in FIGURES 47
and 48, are used in the rotor assembly of FIGURE 49. In FIGURE 49, the magnet
holders shown in FIGURES 47 and 48 cooperate as offset magnet holders. As with
the previously described magnet holders 222, 224 (FIGURES 35 AND 36) and 232,
234 (FIGURE 3?), the magnet holders 240, 242 shown in FIGURES 47 and 48
include connectors 244, 246 for fitting onto the recesses 260, protrusions
258, or
peg 254 of the rotor assembly 252 formed by the hexagonal links 250. Also as
with
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the previous embodiments, the two connectors are offset relative to one
another so as
to provide a variety of connection arrangements.
, FIGURE SO shows a further alternative conductor rotor assembly according
to the present invention. In this non-limiting example, a rotor conductor
assembly
280, such as one of the previously described conductor rotor arrangements,
including
disks, links or other modularly interconnected conductor subassemblies as
necessary,
is utilized and linked in parallel with a variable resistor 282 (not shown) to
produce a
variable speed permanent magnet coupler. The rotor conductor assembly 280 is
used
with a magnet rotor assembly (not shown). The resistance potential can be
varied
adjusting the variable resistor to resist or maximize the magnetic field
potential in the
fixed resistance portion of the conductor rotor assembly. Thus, in a permanent
magnet or electromagnetic system the speed can be adjusted by varying the
resistance
of the conductor circuit resistance. Preferably, the variable resistor is
connected in
parallel across the face of the conductor rotor assembly. The fixed resistor
in the
conductor assembly is preferably a copper resistor, but varistors,
thermistors,
conductive plastics, ceramic conductors, zinc oxide type conductors, others
are also
suitably utilized. Semiconductors, mufti-layer ferromagnetics, and magneto-
resistant
systems can also be layered in this configuration.
Variable speed coupling applications are numerous. For example, windmills
need an increase in the field strength timed for when the blade moves in front
of a
mounting pole. Four stroke internal combustion engines need to have speed
varied to
provide load free operation just after the engine fires. Prior art variable
speed
technologies are not effective at varying the speed at fractions of a second
and then
returning to full engagement in cases like the windmill and four stroke
engine.
FIGURE 51 show an additional alternate embodiment of a magnetic coupler
290 of the present invention. In the non-limiting example shown, the fixed
(typically
air) gap between the permanent magnets 138 of the magnet rotor assembly 292
and
the conductors 294 of the conductor rotor assembly 296 is reduced to zero by
adding
ferrofluids 298. Ferrofluidic material is lubricating, magnetic fluid that
focuses the
flux field between magnets and conductors. In this respect, the ferrofluid 298
maximizes the magnetic field formed between the magnets and the conductors in
the
magnetic coupler. These ferrofluids 298 can also be utilized at different
density levels
(through dilution of the ferrofluids) to vary the magnetic field resistance
between the
magnets and the conductors. This ferrofluidic embodiment of the present
invention
3 5 can be incorporated either in conjunction with, or without the use of the
variable
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resistor circuit connected in parallel with conductor rotor assembly, as
described
above. Although the ferrofluids 298 are shown in FIGURE 51 as extending
between
the disks 28m and 40m, the ferrofluids could alternatively extend only between
the
permanent magnets 138 of the magnet rotor assembly 292 and the conductors 294
of
the conductor rotor assembly 296 and serve the same purpose. Ferrofluids
densities
can also be varied to vary the speed of the magnetic coupler 290. Ferrofluids
298 can
also be used in couplers in which the magnets a "U" shape such as is drown in
FIGURE 11. The U-shape is such an embodiment helps to contain the ferrofluids.
FIGURE 52 shows an additional hexagonal link structure 300 for use in the
invention. The hexagonal link structure 300 includes two disks 302, 304, the
outer
shapes of which substantially match the shape of the hexagonal Links 250. The
two
disks 302, 304 extend substantially parallel to one another and are separated
by a
round core connector 306 (FIGURE 54). A central aperture 308 extends
orthogonal
to the two disks 302, 304, through the two disks 302, 304 and the a round core
connector 306. Six holes 310 extend orthogonally through the two disks 302,
304
and are spaced evenly about the circumference of the disks 302, 304
approximately
half way between the central aperture 308 and the outer edges of the disks.
As can be seen in FIGURE 56, the hexagonal link structures 300 are designed
so that one of the two disks 302, 304 of one of the hexagonal link structures
300 can
be inserted between the two disks 302, 304 of a second hexagonal link
structures 300.
A number of the hexagonal link structures 300 can be assembled to form
structures
(see, for example, FIGURE 55. Concave corners 312 of the two disks 302, 304
press
against the round core connector 306. The round core connector 306 is
preferably
formed from a compressible material so as to provide a low-stress consolidated
part.
The hexagonal link structures 300 described can be used to form rotor
structures or, more preferably, variable resistant conductors. In the variable
resistant
conductors embodiment, the two disks 302, 304 serve as layered offset
hexagons.
Each individual hexagon, preferably the face and back of the hexagon, is wired
in
parallel with a resistance circuit (not shown). This structure and wiring
provides a
layered structure in which the flux field can be reduced. A solid part does
not have
the range resistance that a layered conductor has.
Each hexagon can be wired as a resister independent of the others. To isolate
each of the wired disks 302, 304, thin film of rubber tape 314 (FIGURE 53
only) can
extend around the edges of the two disks 302, 304. The rubber tape 314
compresses
3 5 and provides the insulation needed to separate the hexagons electrically
in the radial
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direction. A film 316 (FIGURE 45 only) on the face of each of the disks 302,
304
provides insulation on the face.
The U shaped magnets or any other magnet systems in the magnet couplings
described above can be assembled from multiple magnets that do not have their
field
directly pointing into the face of the conductor. In prior art magnet
couplers, some of
the magnets were joined and stacked, but all magnets faced north or south and
were
directly pointed toward the conductor. The optimum design is a magnet
composite
such as is produced by Magnet-Solutions in Dublin, Ireland. Magnet Solutions
provides a one Tesla magnet in a very compact design that has many small
magnets
shaped and arranged so as to provide optimum geometries of the magnets related
directly to the field orientation needed to direct the flux where required to
optimize
the system. This type of magnet assembly is called a "multiple geometry
magnetic
field directed magnetic composite" magnet assembly. For example, in one
Magnetic
Solution magnet assembly, the one Tesla power was measurable in the central
hole of
a donut-shaped composite magnet assembly.
All the magnets described in this disclosure could be multiple geometry
magnetic field directed magnetic composite magnets. The multiple geometry
magnetic field directed magnetic composite magnets permit the formation of
lighter
components with high magnet ratings. If the same overall geometry was one
single
magnet, the useful power or the magnet surface would be significantly lower
than
multiple magnets optimized for their geometry and field. For example, low cost
lower
power injected magnets in the 17 MGOe range often do not form an eddy current
strong enough to obtain a permanent magnet coupling. However, multiple
geometry
magnetic field directed magnetic composite magnet assemblies are used, the
assemblies would orient the field and focus the composite of the lower power
magnets
into a 36 MGOe field strength at the "exit point of the fields", for example
at the point
the magnetic field was needed. This design provides a more economical magnet
and a
lighter magnet per torque transfernng across the system.
Minimal or no iron is needed to keeper the back unused side of the multiple
geometry magnetic field directed magnetic composite magnets, because the field
is
directed into a circuit orientation within the magnet cluster. A large heavy
backing
plate would not be needed in the couplings in Figure 11 - 13C to keeper the
magnet
cluster.
The face of the magnets in a multiple geometry magnetic field directed
3 S magnetic composite magnet assemblies would most likely not be
perpendicular or
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parallel to the face of the conductor or magnet rotor. Instead, there would be
clusters
of magnets oriented through the exit point of the magnet cluster face. Magnet
orientation direction applied during the manufacture of magnets has to be
applied
individually to magnets assembled in the multiple geometry magnetic field
directed
magnetic composite magnet assemblies. It is possible to add shunting within
these
multiple geometry magnetic field directed magnetic composite magnet assemblies
to
drop the field within these clusters and vary speed. Alternatively, variable
speed can
be provided by moving one cluster of magnets relative to another by means such
as
piezoelectric mechanical movement, whereby the changed fields will cancel the
potentials of the opposite magnets.
The conductors described above can be made from porous conductive carbon
fibers, such as is commercially available through TechNature, Inc. of Redmond
Washington. The porous conductive carbon materials can be compressed into
dense
materials after manufactured, and manufacturing processing can be varied to
obtain
various densities. Ferroelectric fluids can be absorbed physically into the
voids of the
porous conductive carbon materials. This feature provides a distinct advantage
over
copper conductive material, because copper will not physically hold
ferrofluids, but
the porous conductive carbon materials will. Thus, ferrofluids can be absorbed
into
the porous conductive carbon materials to provide a reservoir of ferrofluids
to
physically contact the magnets positioned at a distance.
As the magnets move relative to the ferrofluid-filled porous conductive carbon
materials, the ferrofluids stiffen and form a strong mechanical "touching"
bond
between the magnet and conductor. This feature allows a smaller, denser
coupling to
be manufactured that still has all the qualities of the prior art of "air gap"
couplings.
The contact is through a lubricating magnetic fluid that will compress and
elongate, so
the system can still be misaligned in every direction and the conductor and
magnets
will maintain fluid contact.
If carbon materials are used for the conductors, these materials can be
"activated" to absorb gases or fluids as common as water. Carbon will absorb
and
"wick" the water into the conductor. The conductor components made from carbon
will release their vapor or gas when heated. This provides a cooling effect on
the
conductor.
It is desirable in some couplings to put magnetocaloric materials in the
carbon
to dump heat from the system. Magnetocaloric materials heat when a magnetic
field
is present and cool when the magnetic field is removed. Carbon materials with
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magnetocaloric materials integrated into their matrix or applied to their
surface with
binders will thermally cycle rapidly. This cycle can be used as a heat pipe to
remove
the heat generated by the slip of the coupling.
While the preferred embodiment of the invention has been illustrated and
described with reference to preferred embodiments thereof, it will be
appreciated that
various changes can be made therein without departing from the spirit and
scope of
the invention as defined in the appended claims.
