Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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ROTARY PISTON TYPE ACTUATOR WITH
MODULAR HOUSING
CLAIM OF PRIORITY
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Patent Application No.
14/170,461 filed on January 31, 2014, which is a continuation in part of and
claims the benefit of the priority to U.S. Patent Application No. 13/778,561,
filed February 27, 2013, U.S. Patent Application No. 13/831,220, filed March
14, 2013, and U.S. Patent Application No. 13/921,904, filed June 19, 2013, the
disclosures of which are incorporated by reference in their entirety.
TECHNICAL FIELD
[0002] This invention relates to an actuator device and more particularly
to
a rotary piston type actuator device wherein the pistons of the rotor are
moved
by fluid under pressure and wherein the actuator device includes a central
actuation assembly adapted for attachment to and external mounting feature
on a member to be actuated.
BACKGROUND
[0003] Rotary hydraulic actuators of various forms are currently used in
industrial mechanical power conversion applications. This industrial usage is
commonly for applications where continuous inertial loading is desired without
the need for load holding for long durations, e.g. hours, without the use of
an
external fluid power supply. Aircraft flight control applications generally
implement loaded positional holding, for example, in a failure mitigation
mode,
using substantially only the blocked fluid column to hold position.
[0004] In certain applications, such as primary flight controls used for
aircraft operation, positional accuracy in load holding by rotary actuators is
desired. Positional accuracy can be improved by minimizing internal leakage
characteristics inherent to the design of rotary actuators. However, it can be
difficult to provide leak-free performance in typical rotary hydraulic
actuators,
e.g., rotary "vane" or rotary "piston" type configurations.
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SUMMARY
[0005] In general, this document relates to rotary actuators.
[0006] In a first aspect, a rotary actuator includes a housing, first
piston
housing assembly comprising a first cavity, a first fluid port in fluid
communication with the first cavity, and a first open end, a second piston
housing assembly comprising a second cavity, a second fluid port in fluid
communication with the second cavity and a second open end, a rotor
assembly rotatably journaled in said housing and comprising a rotary output
shaft and a first rotor arm extending radially outward from the rotary output
io shaft to a first distal end, a second rotor arm extending radially
outward from
the rotary output shaft to a second distal end, and an arcuate-shaped first
piston disposed in said first piston housing assembly for reciprocal movement
in the first piston housing assembly through the first open end along a first
radius of curvature, wherein a first seal, the first cavity, and the first
piston
define a first pressure chamber, and a first portion of the first piston
connects
to the first rotor arm at a first end portion, and an arcuate-shaped second
piston disposed in said second piston housing assembly for reciprocal
movement in the second piston housing assembly along the second radius of
curvature, wherein a second seal, the second cavity, and the second piston
define a second pressure chamber, and a second portion of the second piston
connects to the second rotor arm at a second end portion. The first retainers
and the second retainers are intermeshed along the radius of curvature such
that movement of the rotor assembly urges movement of the first piston and
movement of the first piston urges movement of the rotor assembly.
[0007] Various embodiments can include some, all, or none of the following
features. The first distal end can comprise one or more first retainers, the
second distal end can comprise one or more second retainers, the first end
portion can comprise one or more third retainers and the second end portion
can comprise one or more fourth retainers. The first retainers, the second
retainers, the third retainers, and the fourth retainers can be intermeshed
along
the radius of curvature such that movement of the rotor assembly urges
movement of the first piston and the second piston, and movement of the first
piston and the second piston urges movement of the rotor assembly. The
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rotary actuator can include a first connecting rod, and the first distal end
can
include a first bore, the first end portion can includes a second bore, and
the
first connecting rod can be located within the first bore and the second bore
when the first retainers and the third retainers are intermeshed. The rotary
actuator can include a second connecting rod and the second distal end can
include a third bore, the second end portion can include a fourth bore, and
the
second connecting rod can be located within the third bore and the fourth bore
when the second retainers and the fourth retainers are intermeshed. The
second piston can be oriented in the same rotational direction as the first
piston. The second piston can be oriented in the opposite rotational direction
as the first piston. The first piston housing assembly and the second piston
housing assembly can be coupled to each other. The rotary actuator can
include an outer housing having a bore, the first piston housing assembly and
the second piston housing assembly being assembled to the outer housing
within the bore. The first piston housing assembly can be formed within the
outer housing as a unitary housing. The first piston housing assembly can be
located within a cavity of the outer housing formed as a unitary piston
housing.
The first piston housing assembly can be formed as a unitary piston housing,
the second piston housing can be formed as a unitary piston housing, and the
outer housing can include a housing cavity formed to accommodate the first
piston housing and the second piston housing. The first connecting rod, the
first bore, and the second bore can be configured with cross-sectional
geometries that prevent rotation of the first connecting rod within the first
bore
and the second bore around the longitudinal axis of the first connecting rod.
At
least one of the first retainers and the second retainers or the third
retainers
and the fourth retainers can be formed with radial geometries that prevent
rotation of the first piston away from the radius of curvature. At least one
of
the first retainers and the second retainers or the third retainers and the
fourth
retainers can be connected by one or more fasteners that prevent rotation of
the first piston away from the radius of curvature. The rotary actuator can
include a second connecting rod and the first distal end can include a third
bore, the first end portion can include a fourth bore, and the second
connecting
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rod can be located within the third bore and the fourth bore when the first
retainers and the second retainers are intermeshed.
[0008] In a second aspect, a method of rotary actuation includes
providing
a rotary actuator comprising a housing, a first piston housing assembly
comprising a first cavity, a first fluid port in fluid communication with the
first
cavity, and a first open end, a second piston housing assembly comprising a
second cavity, a second fluid port in fluid communication with the second
cavity and a second open end, a rotor assembly rotatably journaled in said
housing and comprising a rotary output shaft and a first rotor arm extending
io radially outward from the rotary output shaft to a first distal end, a
second rotor
arm extending radially outward from the rotary output shaft to a second distal
end, and an arcuate-shaped first piston disposed in said first piston housing
assembly for reciprocal movement in the first piston housing assembly
through the first open end along a first radius of curvature, wherein a first
seal,
the first cavity, and the first piston define a first pressure chamber, and a
first
portion of the first piston connects to the first rotor arm at a first end
portion,
and an arcuate-shaped second piston disposed in said second piston housing
assembly for reciprocal movement in the second piston housing assembly
along the second radius of curvature, wherein a second seal, the second
cavity, and the second piston define a second pressure chamber, and a
second portion of the second piston connects to the second rotor arm at a
second end portion, wherein movement of the rotor assembly urges movement
of the first piston and the second piston, and movement of the first piston
and
the second piston urges movement of the rotor assembly. The method also
includes urging a portion of the first piston partially out of the first
pressure
chamber to urge rotation of the rotary output shaft in a first direction,
rotating
the rotary output shaft in a second direction opposite that of the first
direction,
and urging the first piston partially into the first pressure chamber to urge
pressurized fluid out the first fluid port.
[0009] Various implementations can include some, all, or none of the
following features. The first distal end can comprise one or more first
retainers, the second distal end can comprise one or more second retainers,
the first end portion can comprise one or more third retainers and the second
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end portion can comprise one or more fourth retainers. The first retainers,
the
second retainers, the third retainers, and the fourth retainers can be
intermeshed along the radius of curvature such that movement of the rotor
assembly urges movement of the first piston and the second piston, and
movement of the first piston and the second piston urges movement of the
rotor assembly. The rotary actuator can include a first connecting rod and
wherein the first distal end can include a first bore, the first end portion
can
include a second bore, and the first connecting rod can be located within the
first bore and the second bore when the first retainers and the third
retainers
io are intermeshed. The rotary actuator can include a second connecting rod
and wherein the second distal end can include a third bore, the second end
portion can include a fourth bore, and the second connecting rod can be
located within the third bore and the fourth bore when the second retainers
and
the fourth retainers are intermeshed. The second piston can be oriented in the
same rotational direction as the first piston. The second piston can be
oriented
in the opposite rotational direction as the first piston. The first piston
housing
assembly and the second piston hosing assembly are coupled to each other.
The rotary actuator can include an outer housing having a bore, the first
piston
housing assembly and the second piston housing assembly being assembled
to the outer housing within the bore. The first piston housing assembly can be
formed within the outer housing as a unitary housing. The first piston housing
assembly can be located within a cavity of the outer housing formed as a
unitary piston housing. The first piston housing assembly can be formed as a
unitary piston housing, the second piston housing can be formed as a unitary
piston housing, and the outer housing can include a housing cavity formed to
accommodate the first piston housing and the second piston housing. The first
connecting rod, the first bore, and the second bore can be configured with
cross-sectional geometries that prevent rotation of the first connecting rod
within the first bore and the second bore around the longitudinal axis of the
first
connecting rod. At least one of the first retainers and the second retainers
or
the third retainers and the fourth retainers can be formed with radial
geometries that prevent rotation of the first piston away from the radius of
curvature. At least one of the first retainers and the second retainers or the
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third retainers and the fourth retainers can be connected by one or more
fasteners that prevent rotation of the first piston away from the radius of
curvature. The rotary actuator can include a second connecting rod and the
first distal end can include a third bore, the first end portion can include a
fourth bore, and the second connecting rod can be located within the third
bore
and the fourth bore when the first retainers and the second retainers are
intermeshed.
[0010] In a third aspect, a rotary actuator includes a first piston
housing
assembly comprising a first cavity, a first fluid port in fluid communication
with
io the first cavity, and a first open end, a second piston housing assembly
comprising a second cavity, a second fluid port in fluid communication with
the
second cavity, and a second open end. A rotor assembly is rotatably journaled
in said first piston housing assembly and said second piston housing
assembly, and includes a rotary output shaft a first rotor arm extending
radially outward from the rotary output shaft to a first distal end having one
or
more first retainers, a second rotor arm extending radially outward from the
rotary output shaft to a second distal end comprising one or more second
retainers, an arcuate-shaped first piston disposed in said first piston
housing
assembly for reciprocal movement in the first piston housing assembly
through the first open end along a first radius of curvature, wherein a first
seal,
the first cavity, and the first piston define a first pressure chamber, and a
first
portion of the first piston connects to the first rotor arm at a first end
portion
comprising one or more third retainers, and an arcuate-shaped second piston
disposed in said second piston housing assembly for reciprocal movement in
the second piston housing assembly through the second open end along a
second radius of curvature, wherein a second seal, the second cavity, and the
second piston define a second pressure chamber, and a second portion of the
second piston connects to the second rotor arm at a second end portion
comprising one or more fourth retainers. The first retainers, the second
retainers, the third retainers, and the fourth retainers are intermeshed along
the radius of curvature such that movement of the rotor assembly urges
movement of the first piston and the second piston, and movement of the first
piston and the second piston urges movement of the rotor assembly.
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[0011] Various embodiments can include some, all, or none of the
following
features. The second piston can be oriented in the same rotational direction
as the first piston. The second piston can be oriented in the opposite
rotational
direction as the first piston. The rotary actuator can include a housing
having a
bore, the first piston housing assembly and the second piston housing
assembly being assembled to the housing within the bore. The rotary actuator
can include at least one end cap assembled to at least one axial end of the
first piston housing assembly. The first piston housing assembly and the
second piston housing assembly can be coupled to each other. The rotary
io actuator can also include a first connecting rod and the first distal
end can
include a first bore, the first end portion can include a second bore, and the
first connecting rod can be located within the first bore and the second bore
when the first retainers and the third retainers are intermeshed. The first
connecting rod, the first bore, and the second bore can be configured with
cross-sectional geometries that prevent rotation of the first connecting rod
within the first bore and the second bore around the longitudinal axis of the
first
connecting rod. At least one of the first retainers and the second retainers
or
the third retainers and the fourth retainers can be formed with radial
geometries that prevent rotation of the first piston or the second piston away
from the radius of curvature. At least one of the first retainers and the
second
retainers or the third retainers and the fourth retainers can be connected by
one or more fasteners that prevent rotation of the first piston or the second
piston away from the radius of curvature. The rotary actuator can include a
second connecting rod and the first distal end can include a third bore, the
first
end portion can include a fourth bore, and the second connecting rod can be
located within the third bore and the fourth bore when the first retainers and
the third retainers are intermeshed.
[0012] In a fourth aspect, a method of rotary actuation includes
providing a
rotary actuator that includes a first piston housing assembly comprising a
first
cavity, a first fluid port in fluid communication with the first cavity, and a
first
open end, a second piston housing assembly comprising a second cavity, a
second fluid port in fluid communication with the second cavity, and a second
open end. The actuator also includes a rotor assembly rotatably journaled in
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said first piston housing assembly and said second piston housing assembly,
and has a rotary output shaft, a first rotor arm extending radially outward
from
the rotary output shaft to a first distal end comprising one or more first
retainers, a second rotor arm extending radially outward from the rotary
output
shaft to a second distal end, an arcuate-shaped first piston disposed in said
first piston housing assembly for reciprocal movement in the first piston
housing assembly through the first open end along a first radius of curvature,
wherein a first seal, the first cavity, and the first piston define a first
pressure
chamber, and a first portion of the first piston connects to the first rotor
arm at
io a first end portion comprising one or more second retainers, and an
arcuate-
shaped second piston disposed in said second piston housing assembly for
reciprocal movement in the second piston housing assembly through the
second open end along a second radius of curvature, wherein a second seal,
the second cavity, and the second piston define a second pressure chamber,
and a second portion of the second piston connects to the second rotor arm at
a second end portion comprising one or more third retainers. The first
retainers, the second retainers, and the third retainers are intermeshed along
the radius of curvature such that movement of the rotor assembly urges
movement of the first piston and the second piston, and movement of the first
piston and the second piston urges movement of the rotor assembly. The
method also includes urging a portion of the first piston partially out of the
first
pressure chamber to urge rotation of the rotary output shaft in a first
direction,
rotating the rotary output shaft in a second direction opposite that of the
first
direction, and urging the first piston partially into the first pressure
chamber to
urge pressurized fluid out the first fluid port.
[0013] Various implementations can include some, all, or none of the
following features. The second piston can be oriented in the same rotational
direction as the first piston. The second piston can be oriented in the
opposite
rotational direction as the first piston. The rotary actuator can include a
housing having a bore, the first piston housing assembly and the second
piston housing assembly being assembled to the housing within the bore. The
rotary actuator can include at least one end cap assembled to at least one
axial end of the first piston housing assembly. The first piston housing
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assembly and the second piston housing assembly can be coupled to each
other. The rotary actuator can include a first connecting rod and wherein the
first distal end further comprises a first bore, the first end portion further
comprises a second bore, and the first connecting rod is located within the
first
bore and the second bore when the first retainers and the third retainers are
intermeshed. The first connecting rod, the first bore, and the second bore can
be configured with cross-sectional geometries that prevent rotation of the
first
connecting rod within the first bore and the second bore around the
longitudinal axis of the first connecting rod. At least one of the first
retainers
io and the second retainers or the third retainers and the fourth retainers
can be
formed with radial geometries that prevent rotation of the first piston or the
second piston away from the radius of curvature. At least one of the first
retainers and the second retainers or the third retainers and the fourth
retainers can be connected by one or more fasteners that prevent rotation of
the first piston or the second piston away from the radius of curvature. The
rotary actuator can include a second connecting rod and the first distal end
can
include a third bore, the first end portion can include a fourth bore, and the
second connecting rod can be located within the third bore and the fourth bore
when the first retainers and the third retainers are intermeshed.
[0014] In a fifth aspect, a rotary actuator includes a first piston housing
comprising a first cavity, a fluid port in fluid communication with the first
cavity,
and an open end, a housing assembly comprising a first outer housing
comprising a first recess formed to partly accommodate the first piston
housing, a second outer housing comprising a second recess formed to partly
accommodate the first piston housing, wherein the second outer housing is
configured to be assembled to the outer housing such that the first recess and
the second recess define a second cavity configured to accommodate the first
piston housing, and an arcuate-shaped first piston disposed in said first
piston
housing for reciprocal movement in the first piston housing through the open
end along a radius of curvature, wherein a first seal, the first cavity, and
the
first piston define a pressure chamber.
The rotary actuator can further comprise a second piston housing comprising a
third cavity, a fluid port in fluid communication with the third cavity, and
an
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open end, and a fluid conduit connecting the first cavity and the third
cavity,
wherein the second cavity is further configured to accommodate the second
piston housing.
[0015] In a sixth aspect, a method of assembling a rotary actuator
comprises providing a first piston housing comprising a first cavity, a fluid
port
in fluid communication with the cavity, and an open end, providing a housing
assembly comprising a first outer housing comprising a first recess formed to
partly accommodate the first piston housing, a second outer housing
comprising a second recess formed to partly accommodate the first piston
housing, wherein the second outer housing is configured to be assembled to
the first piston housing such that the first recess and the second recess
define
a second cavity configured to accommodate the first piston housing, and
providing an arcuate-shaped first piston disposed in said first piston housing
for reciprocal movement in the first piston housing through the open end along
a radius of curvature, wherein a first seal, the first cavity, and the first
piston
define a first pressure chamber, inserting a portion of the first piston at
least
partly into the first pressure chamber; and positioning the first piston
housing
within the first recess and the second recess such that the second cavity is
defined and the first piston housing is accommodated within the second cavity.
The method can further comprise providing a second piston housing
comprising a third cavity, a fluid port in fluid communication with the
cavity, and
an open end, providing a fluid conduit connecting the first cavity and the
third
cavity, providing an arcuate-shaped second piston disposed in said second
piston housing for reciprocal movement in the second piston housing through
the open end along a radius of curvature, wherein a second seal, the second
cavity, and the second piston define a second pressure chamber; wherein the
second cavity is further configured to accommodate the second piston
housing, inserting a portion of the second piston at least partly into the
second
pressure chamber, and positioning the second piston housing within the first
recess and the second recess such that the second cavity is defined and the
first piston housing and the second piston housing are accommodated within
the second cavity.
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[0016] The systems and techniques described herein may provide one or
more of the following advantages. First, piston ends can be intermeshed with
rotor arm ends to prevent separation of the pistons from the rotor arms.
Second, piston ends can be intermeshed with rotor arm ends to prevent a
connector pin from becoming dislodged if the connector pin were to break.
Third, modular piston housings can reduce the cost and/or complexity of rotary
piston actuators.
[0017] The details of one or more implementations are set forth in the
accompanying drawings and the description below. Other features and
io advantages will be apparent from the description and drawings, and from
the
claims.
DESCRIPTION OF DRAWINGS
[0018] FIG. 1 is a perspective view of an example rotary piston-type
actuator.
[0019] FIG. 2 is a perspective view of an example rotary piston assembly.
[0020] FIG. 3 is a perspective cross-sectional view of an example rotary
piston-type actuator.
[0021] FIG. 4 is a perspective view of another example rotary piston-type
actuator.
[0022] FIGs. 5 and 6 are cross-sectional views of an example rotary piston-
type actuator.
[0023] FIG. 7 is a perspective view of another embodiment of a rotary
piston-type actuator.
[0024] FIG. 8 is a perspective view of another example of a rotary piston-
type actuator.
[0025] FIGs. 9 and 10 show and example rotary piston-type actuator in
example extended and retracted configurations.
[0026] FIG. 11 is a perspective view of another example of a rotary
piston-
type actuator.
[0027] FIGs. 12-14 are perspective and cross-sectional views of another
example rotary piston-type actuator.
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[0028] FIGs. 15 and 16 are perspective and cross-sectional views of
another example rotary piston-type actuator that includes another example
rotary piston assembly.
[0029] FIGs. 17 and 18 are perspective and cross-sectional views of
another example rotary piston-type actuator that includes another example
rotary piston assembly.
[0030] FIGs. 19 and 20 are perspective and cross-sectional views of
another example rotary piston-type actuator.
[0031] FIGs. 21A-21C are cross-sectional and perspective views of an
io example rotary piston.
[0032] FIGs. 22 and 23 illustrate a comparison of two example rotor shaft
embodiments.
[0033] FIG. 24 is a perspective view of another example rotary piston.
[0034] FIG. 25 is a flow diagram of an example process for performing
rotary actuation.
[0035] FIG. 26 is a perspective view of another example rotary piston-
type
actuator.
[0036] FIG. 27 is a cross-sectional view of another example rotary piston
assembly.
[0037] FIG. 28 is a perspective cross-sectional view of another example
rotary piston-type actuator.
[0038] FIG. 29A is a perspective view from above of an example rotary-
piston type actuator with a central actuation assembly.
[0039] FIG. 29B is a top view of the actuator of FIG 29A.
[0040] FIG. 29C is a perspective view from the right side and above
illustrating the actuator of FIG. 29A with a portion of the central actuation
assembly removed for illustration purposes.
[0041] FIG. 29D is a lateral cross section view taken at section AA of
the
actuator of Fig 29B.
[0042] FIG. 29E is a partial perspective view from cross section AA of FIG.
29B.
[0043] FIG. 30A is a perspective view from above of an example rotary
actuator with a central actuation assembly.
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[0044] FIG. 30B is another perspective view from above of the example
rotary actuator of FIG. 30A.
[0045] FIG. 30C is a top view of the example rotary actuator of FIG. 30A.
[0046] FIG. 30D is an end view of the example rotary actuator of FIG.
30A.
[0047] FIG. 30E is a partial perspective view from cross section AA of FIG.
30C.
[0048] FIG. 31A is a perspective view from above of another example
rotary actuator with a central actuation assembly.
[0049] FIG. 31B is another perspective view from above of the example
io rotary actuator of FIG. 31A.
[0050] FIG. 31C is a top view of the example rotary actuator of FIG. 31A.
[0051] FIG. 31D is an end view of the example rotary actuator of FIG.
31A.
[0052] FIG. 31E is a partial perspective view from cross section AA of
FIG.
31C.
[0053] FIG. 32 is an exploded perspective view of another example
pressure chamber assembly.
[0054] FIGs. 33A-33C are exploded and assembled perspective views of
another example rotary piston assembly.
[0055] FIGs. 34A and 34B are perspective views of another example rotary
piston.
[0056] FIG. 35A is a perspective view of another example pressure
chamber assembly.
[0057] FIG. 35B is a perspective partial cutaway view of the example
pressure chamber assembly of FIG. 35A.
[0058] FIG. 35C is a perspective exploded view of the example pressure
chamber assembly of FIG. 35A.
[0059] FIG. 36 is a perspective view of an example piston housing
assembly.
DETAILED DESCRIPTION
[0060] This document describes devices for producing rotary motion. In
particular, this document describes devices that can convert fluid
displacement
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into rotary motion through the use of components more commonly used for
producing linear motion, e.g., hydraulic or pneumatic linear cylinders. Vane-
type rotary actuators are relatively compact devices used to convert fluid
motion into rotary motion. Rotary vane actuators (RVA), however, generally
use seals and component configurations that exhibit cross-vane leakage of the
driving fluid. Such leakage can affect the range of applications in which such
designs can be used. Some applications may require a rotary actuator to hold
a rotational load in a selected position for a predetermined length of time,
substantially without rotational movement, when the actuator's fluid ports are
blocked. For example, some aircraft applications may require that an actuator
hold a flap or other control surface that is under load (e.g., through wind
resistance, gravity or g-forces) at a selected position when the actuator's
fluid
ports are blocked. Cross-vane leakage, however, can allow movement from
the selected position.
[0061] Linear pistons use relatively mature sealing technology that
exhibits
well-understood dynamic operation and leakage characteristics that are
generally better than rotary vane actuator type seals. Linear pistons,
however,
require additional mechanical components in order to adapt their linear
motions to rotary motions. Such linear-to-rotary mechanisms are generally
larger and heavier than rotary vane actuators that are capable of providing
similar rotational actions, e.g., occupying a larger work envelope. Such
linear-
to-rotary mechanisms may also generally be installed in an orientation that is
different from that of the load they are intended to drive, and therefore may
provide their torque output indirectly, e.g., installed to push or pull a
lever arm
that is at a generally right angle to the axis of the axis of rotation of the
lever
arm. Such linear-to-rotary mechanisms may therefore become too large or
heavy for use in some applications, such as aircraft control where space and
weight constraints may make such mechanisms impractical for use.
[0062] In general, rotary piston assemblies use curved pressure chambers
and curved pistons to controllably push and pull the rotor arms of a rotor
assembly about an axis. In use, certain embodiments of the rotary piston
assemblies described herein can provide the positional holding characteristics
generally associated with linear piston-type fluid actuators, to rotary
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applications, and can do so using the relatively more compact and lightweight
envelopes generally associated with rotary vane actuators.
[0063] FIGs. 1-3 show various views of the components of an example
rotary piston-type actuator 100. Referring to FIG. 1, a perspective view of
the
example rotary piston-type actuator 100 is shown. The actuator 100 includes
a rotary piston assembly 200 and a pressure chamber assembly 300. The
actuator 100 includes a first actuation section 110 and a second actuation
section 120. In the example of actuator 100, the first actuation section 110
is
configured to rotate the rotary piston assembly 200 in a first direction,
e.g.,
counter-clockwise, and the second actuation section 120 is configured to
rotate the rotary piston assembly 200 in a second direction substantially
opposite the first direction, e.g., clockwise.
[0064] Referring now to FIG. 2, a perspective view of the example rotary
piston assembly 200 is shown apart from the pressure chamber assembly 300.
The rotary piston assembly 200 includes a rotor shaft 210. A plurality of
rotor
arms 212 extend radially from the rotor shaft 210, the distal end of each
rotor
arm 212 including a bore (not shown) substantially aligned with the axis of
the
rotor shaft 210 and sized to accommodate one of the collection of connector
pins 214.
[0065] As shown in FIG. 2, the first actuation section 110 includes a pair
of
rotary pistons 250, and the second actuation section 120 includes a pair of
rotary pistons 260. While the example actuator 100 includes two pairs of the
rotary pistons 250, 260, other embodiments can include greater and/or lesser
numbers of cooperative and opposing rotary pistons. Examples of other such
embodiments will be discussed below, for example, in the descriptions of FIGs.
4-25
[0066] In the example rotary piston assembly shown in FIG. 2, each of the
rotary pistons 250, 260 includes a piston end 252 and one or more connector
arms 254. The piston end 252 is formed to have a generally semi-circular
body having a substantially smooth surface. Each of the connector arms 254
includes a bore 256 substantially aligned with the axis of the semi-circular
body of the piston end 252 and sized to accommodate one of the connector
pins 214.
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[0067] The rotary pistons 260 in the example assembly of FIG. 2 are
oriented substantially opposite each other in the same rotational direction.
The
rotary pistons 250 are oriented substantially opposite each other in the same
rotational direction, but opposite that of the rotary pistons 260. In some
embodiments, the actuator 100 can rotate the rotor shaft 210 about 60
degrees total.
[0068] Each of the rotary pistons 250, 260 of the example assembly of
FIG.
2 may be assembled to the rotor shaft 210 by aligning the connector arms 254
with the rotor arms 212 such that the bores (not shown) of the rotor arms 212
io align with the bores 265. The connector pins 214 may then be inserted
through the aligned bores to create hinged connections between the pistons
250, 260 and the rotor shaft 210. Each connector pin 214 is slightly longer
than the aligned bores. In the example assembly, about the circumferential
periphery of each end of each connector pin 214 that extends beyond the
aligned bores is a circumferential recess (not shown) that can accommodate a
retaining fastener (not shown), e.g., a snap ring or spiral ring.
[0069] FIG. 3 is a perspective cross-sectional view of the example rotary
piston-type actuator 100. The illustrated example shows the rotary pistons 260
inserted into a corresponding pressure chamber 310 formed as an arcuate
cavity in the pressure chamber assembly 300. The rotary pistons 250 are also
inserted into corresponding pressure chambers 310, not visible in this view.
[0070] In the example actuator 100, each pressure chamber 310 includes a
seal assembly 320 about the interior surface of the pressure chamber 310 at
an open end 330. In some implementations, the seal assembly 320 can be a
circular or semi-circular sealing geometry retained on all sides in a standard
seal groove. In some implementations, commercially available reciprocating
piston or cylinder type seals can be used. For example, commercially available
seal types that may already be in use for linear hydraulic actuators flying on
current aircraft may demonstrate sufficient capability for linear load and
position holding applications. In some implementations, the sealing complexity
of the actuator 100 may be reduced by using a standard, e.g., commercially
available, semi-circular, unidirectional seal designs generally used in linear
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hydraulic actuators. In some embodiments, the seal assembly 320 can be a
one-piece seal.
[0071] In some embodiments of the example actuator 100, the seal
assembly 320 may be included as part of the rotary pistons 250, 260. For
example, the seal assembly 320 may be located near the piston end 252,
opposite the connector arm 254, and slide along the interior surface of the
pressure chamber 310 to form a fluidic seal as the rotary piston 250, 260
moves in and out of the pressure chamber 310. An example actuator that
uses such piston-mounted seal assemblies will be discussed in the
io descriptions of FIGs. 26-28. In some embodiments, the seal 310 can act
as a
bearing. For example, the seal assembly 320 may provide support for the
piston 250, 260 as it moves in and out of the pressure chamber 310.
[0072] In some embodiments, the actuator 100 may include a wear
member between the piston 250, 260 and the pressure chamber 310. For
example, a wear ring may be included in proximity to the seal assembly 320.
The wear ring may act as a pilot for the piston 250, 260, and/or act as a
bearing providing support for the piston 250, 260.
[0073] In the example actuator 100, when the rotary pistons 250, 260 are
inserted through the open ends 330, each of the seal assemblies 320 contacts
the interior surface of the pressure chamber 310 and the substantially smooth
surface of the piston end 252 to form a substantially pressure-sealed region
within the pressure chamber 310. Each of the pressure chambers 310 may
include a fluid port 312 formed through the pressure chamber assembly 300,
through which pressurized fluid may flow. Upon introduction of pressurized
fluid, e.g., hydraulic oil, water, air, gas, into the pressure chambers 310,
the
pressure differential between the interior of the pressure chambers 310 and
the ambient conditions outside the pressure chambers 310 causes the piston
ends 252 to be urged outward from the pressure chambers 310. As the piston
ends 252 are urged outward, the pistons 250, 260 urge the rotary piston
assembly 200 to rotate.
[0074] In the example of the actuator 100, cooperative pressure chambers
may be fluidically connected by internal or external fluid ports. For example,
the pressure chambers 310 of the first actuation section 110 may be
fluidically
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interconnected to balance the pressure between the pressure chambers 310.
Similarly the pressure chambers 310 of the second actuation section 120 may
be fluidically interconnected to provide similar pressure balancing. In some
embodiments, the pressure chambers 310 may be fluidically isolated from
each other. For example, the pressure chambers 310 may each be fed by an
independent supply of pressurized fluid.
[0075] In the example of the actuator 100, the use of the alternating
arcuate, e.g., curved, rotary pistons 250, 260 arranged substantially opposing
each other operates to translate the rotor arms in an arc-shaped path about
io the axis of the rotary piston assembly 200, thereby rotating the rotor
shaft 210
clockwise and counter-clockwise in a substantially torque balanced
arrangement. Each cooperative pair of pressure chambers 310 operates uni-
directionally in pushing the respective rotary piston 250 outward, e.g.,
extension, to drive the rotor shaft 210 in the specific direction. To reverse
direction, the opposing cylinder section's 110 pressure chambers 260 are
pressurized to extend their corresponding rotary pistons 260 outward.
[0076] The pressure chamber assembly 300, as shown, includes a
collection of openings 350. In general, the openings 350 provide space in
which the rotor arms 212 can move when the rotor shaft 210 is partly rotated.
In some implementations, the openings 350 can be formed to remove material
from the pressure chamber assembly 300, e.g., to reduce the mass of the
pressure chamber assembly 300. In some implementations, the openings 350
can be used during the process of assembly of the actuator 100. For example,
the actuator 100 can be assembled by inserting the rotary pistons 250, 260
through the openings 350 such that the piston ends 252 are inserted into the
pressure chambers 310. With the rotary pistons 250, 260 substantially fully
inserted into the pressure chambers 310, the rotor shaft 210 can be
assembled to the actuator 100 by aligning the rotor shaft 210 with an axial
bore 360 formed along the axis of the pressure chamber assembly 300, and by
aligning the rotor arms 212 with a collection of keyways 362 formed along the
axis of the pressure chamber assembly 300. The rotor shaft 210 can then be
inserted into the pressure chamber assembly 300. The rotary pistons 250, 260
can be partly extracted from the pressure chambers 310 to substantially align
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the bores 256 with the bores of the rotor arms 212. The connector pins 214
can then be passed through the keyways 362 and the aligned bores to connect
the rotary pistons 250, 260 to the rotor shaft 210. The connector pins 214 can
be secured longitudinally by inserting retaining fasteners through the
openings
350 and about the ends of the connector pins 214. The rotor shaft 210 can be
connected to an external mechanism as an output shaft in order to transfer the
rotary motion of the actuator 100 to other mechanisms. A bushing or bearing
362 is fitted between the rotor shaft 210 and the axial bore 360 at each end
of
the pressure chamber assembly 300.
[0077] In some embodiments, the rotary pistons 250, 260 may urge rotation
of the rotor shaft 210 by contacting the rotor arms 212. For example, the
piston ends 252 may not be coupled to the rotor arms 212. Instead, the piston
ends 252 may contact the rotor arms 212 to urge rotation of the rotor shaft as
the rotary pistons 250, 260 are urged outward from the pressure chambers
310. Conversely, the rotor arms 212 may contact the piston ends 252 to urge
the rotary pistons 250, 260 back into the pressure chambers 310.
[0078] In some embodiments, a rotary position sensor assembly (not
shown) may be included in the actuator 100. For example, an encoder may be
used to sense the rotational position of the rotor shaft 210 relative to the
pressure chamber assembly or another feature that remains substantially
stationary relative to the rotation of the shaft 210. In some implementations,
the rotary position sensor may provide signals that indicate the position of
the
rotor shaft 210 to other electronic or mechanical modules, e.g., a position
controller.
[0079] In use, pressurized fluid in the example actuator 100 can be applied
to the pressure chambers 310 of the second actuation section 120 through the
fluid ports 312. The fluid pressure urges the rotary pistons 260 out of the
pressure chambers 310. This movement urges the rotary piston assembly 200
to rotate clockwise. Pressurized fluid can be applied to the pressure chambers
310 of the first actuation section 110 through the fluid ports 312. The fluid
pressure urges the rotary pistons 250 out of the pressure chambers 310. This
movement urges the rotary piston assembly 200 to rotate counter-clockwise.
The fluid conduits can also be blocked fluidically to cause the rotary piston
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assembly 200 to substantially maintain its rotary position relative to the
pressure chamber assembly 300.
[0080] In some embodiments of the example actuator 100, the pressure
chamber assembly 300 can be formed from a single piece of material. For
example, the pressure chambers 310, the openings 350, the fluid ports 312,
the keyways 362, and the axial bore 360 may be formed by molding,
machining, or otherwise forming a unitary piece of material.
[0081] FIG. 4 is a perspective view of another example rotary piston-type
actuator 400. In general, the actuator 400 is similar to the actuator 100, but
io instead of using opposing pairs of rotary pistons 250, 260, each acting
uni-
directionally to provide clockwise and counter-clockwise rotation, the
actuator
400 uses a pair of bidirectional rotary pistons.
[0082] As shown in FIG. 4, the actuator 400 includes a rotary piston
assembly that includes a rotor shaft 412 and a pair of rotary pistons 414. The
rotor shaft 412 and the rotary pistons 414 are connected by a pair of
connector
pins 416.
[0083] The example actuator shown in FIG. 4 includes a pressure chamber
assembly 420. The pressure chamber assembly 420 includes a pair of
pressure chambers 422 formed as arcuate cavities in the pressure chamber
assembly 420. Each pressure chamber 422 includes a seal assembly 424
about the interior surface of the pressure chamber 422 at an open end 426.
The seal assemblies 424 contact the inner walls of the pressure chambers 422
and the rotary pistons 414 to form fluidic seals between the interiors of the
pressure chambers 422 and the space outside. A pair of fluid ports 428 is in
fluidic communication with the pressure chambers 422. In use, pressurized
fluid can be applied to the fluid ports 428 to urge the rotary pistons 414
partly
out of the pressure chambers 422, and to urge the rotor shaft 412 to rotate in
a
first direction, e.g., clockwise in this example.
[0084] The pressure chamber assembly 420 and the rotor shaft 412 and
rotary pistons 414 of the rotary piston assembly may be structurally similar
to
corresponding components found in to the second actuation section 120 of the
actuator 100. In use, the example actuator 400 also functions substantially
similarly to the actuator 100 when rotating in a first direction when the
rotary
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pistons 414 are being urged outward from the pressure chambers 422. e.g.,
clockwise in this example. As will be discussed next, the actuator 400 differs
from the actuator 100 in the way that the rotor shaft 412 is made to rotate in
a
second direction, e.g., counter-clockwise in this example.
[0085] To provide actuation in the second direction, the example actuator
400 includes an outer housing 450 with a bore 452. The pressure chamber
assembly 420 is formed to fit within the bore 452. The bore 452 is fluidically
sealed by a pair of end caps (not shown). With the end caps in place, the bore
452 becomes a pressurizable chamber. Pressurized fluid can flow to and from
io the bore 452 through a fluid port 454. Pressurized fluid in the bore 452
is
separated from fluid in the pressure chambers 422 by the seals 426.
[0086] Referring now to FIG. 5, the example actuator 400 is shown in a
first
configuration in which the rotor shaft 412 has been rotated in a first
direction,
e.g., clockwise, as indicated by the arrows 501. The rotor shaft 412 can be
rotated in the first direction by flowing pressurized fluid into the pressure
chambers 422 through the fluid ports 428, as indicated by the arrows 502. The
pressure within the pressure chambers 422 urges the rotary pistons 414 partly
outward from the pressure chambers 422 and into the bore 452. Fluid within
the bore 452, separated from the fluid within the pressure chambers 422 by
the seals 424 and displaced by the movement of the rotary pistons 414, is
urged to flow out the fluid port 454, as indicated by the arrow 503.
[0087] Referring now to FIG. 6, the example actuator 400 is shown in a
second configuration in which the rotor shaft 412 has been rotated in a second
direction, e.g., counter-clockwise, as indicated by the arrows 601. The rotor
shaft 412 can be rotated in the second direction by flowing pressurized fluid
into the bore 452 through the fluid port 454, as indicated by the arrow 602.
The pressure within the bore 452 urges the rotary pistons 414 partly into the
pressure chambers 422 from the bore 452. Fluid within the pressure
chambers 422, separated from the fluid within the bore 452 by the seals 424
and displaced by the movement of the rotary pistons 414, is urged to flow out
the fluid ports 428, as indicated by the arrows 603. In some embodiments,
one or more of the fluid ports 428 and 454 can be oriented radially relative
to
the axis of the actuator 400, as illustrated in FIGs. 4-6, however in some
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embodiments one or more of the fluid ports 428 and 454 can be oriented
parallel to the axis of the actuator 400 or in any other appropriate
orientation.
[0088] FIG. 7 is a perspective view of another embodiment of a rotary
piston assembly 700. In the example actuator 100 of FIG. 1, two opposing
pairs of rotary pistons were used, but in other embodiments other numbers
and configurations of rotary pistons and pressure chambers can be used. In
the example of the assembly 700, a first actuation section 710 includes four
rotary pistons 712 cooperatively operable to urge a rotor shaft 701 in a first
direction. A second actuation section 720 includes four rotary pistons 722
io cooperatively operable to urge the rotor shaft 701 in a second
direction.
[0089] Although examples using four rotary pistons, e.g., actuator 100,
and
eight rotary pistons, e.g., assembly 700, have been described, other
configurations may exist. In some embodiments, any appropriate number of
rotary pistons may be used in cooperation and/or opposition. In some
embodiments, opposing rotary pistons may not be segregated into separate
actuation sections, e.g., the actuation sections 710 and 720. While
cooperative pairs of rotary pistons are used in the examples of actuators 100,
400, and assembly 700, other embodiments exist. For example, clusters of
two, three, four, or more cooperative or oppositional rotary pistons and
pressure chambers may be arranged radially about a section of a rotor shaft.
As will be discussed in the descriptions of FIGs. 8-10, a single rotary piston
may be located at a section of a rotor shaft. In some embodiments,
cooperative rotary pistons may be interspersed alternatingly with opposing
rotary pistons. For example, the rotary pistons 712 may alternate with the
rotary pistons 722 along the rotor shaft 701.
[0090] FIG. 8 is a perspective view of another example of a rotary piston-
type actuator 800. The actuator 800 differs from the example actuators 100
and 400, and the example assembly 700 in that instead of implementing
cooperative pairs of rotary pistons along a rotor shaft, e.g., two of the
rotary
pistons 250 are located radially about the rotor shaft 210, individual rotary
pistons are located along a rotor shaft.
[0091] The example actuator 800 includes a rotor shaft 810 and a pressure
chamber assembly 820. The actuator 800 includes a first actuation section
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801 and a second actuation section 802. In the example actuator 800, the first
actuation section 801 is configured to rotate the rotor shaft 810 in a first
direction, e.g., clockwise, and the second actuation section 802 is configured
to rotate the rotor shaft 810 in a second direction substantially opposite the
first
direction, e.g., counter-clockwise.
[0092] The first actuation section 801 of example actuator 800 includes a
rotary piston 812, and the second actuation section 802 includes a rotary
piston 822. By implementing a single rotary piston 812, 822 at a given
longitudinal position along the rotor shaft 810, a relatively greater range of
rotary travel may be achieved compared to actuators that use pairs of rotary
pistons at a given longitudinal position along the rotary piston assembly,
e.g.,
the actuator 100. In some embodiments, the actuator 800 can rotate the rotor
shaft 810 about 145 degrees total.
[0093] In some embodiments, the use of multiple rotary pistons 812, 822
along the rotor shaft 810 can reduce distortion of the pressure chamber
assembly 820, e.g., reduce bowing out under high pressure. In some
embodiments, the use of multiple rotary pistons 812, 822 along the rotor shaft
810 can provide additional degrees of freedom for each piston 812, 822. In
some embodiments, the use of multiple rotary pistons 812, 822 along the rotor
shaft 810 can reduce alignment issues encountered during assembly or
operation. In some embodiments, the use of multiple rotary pistons 812, 822
along the rotor shaft 810 can reduce the effects of side loading of the rotor
shaft 810.
[0094] FIG. 9 shows the example actuator 800 with the rotary piston 812
in
a substantially extended configuration. A pressurized fluid is applied to a
fluid
port 830 to pressurize an arcuate pressure chamber 840 formed in the
pressure chamber assembly 820. Pressure in the pressure chamber 840 urges
the rotary piston 812 partly outward, urging the rotor shaft 810 to rotate in
a
first direction, e.g., clockwise.
[0095] FIG. 10 shows the example actuator 800 with the rotary piston 812
in a substantially retracted configuration. Mechanical rotation of the rotor
shaft
810, e.g., pressurization of the actuation section 820, urges the rotary
piston
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812 partly inward, e.g., clockwise. Fluid in the pressure chamber 840
displaced by the rotary piston 812 flows out through the fluid port 830.
[0096] The example actuator 800 can be assembled by inserting the rotary
piston 812 into the pressure chamber 840. Then the rotor shaft 810 can be
inserted longitudinally through a bore 850 and a keyway 851. The rotary
piston 812 is connected to the rotor shaft 810 by a connecting pin 852.
[0097] FIG. 11 is a perspective view of another example of a rotary
piston-
type actuator 1100. In general, the actuator 1100 is similar to the example
actuator 800, except multiple rotary pistons are used in each actuation
section.
[0098] The example actuator 1100 includes a rotary piston assembly 1110
and a pressure chamber assembly 1120. The actuator 1100 includes a first
actuation section 1101 and a second actuation section 1102. In the example
of actuator 1100, the first actuation section 1101 is configured to rotate the
rotary piston assembly 1110 in a first direction, e.g., clockwise, and the
second
actuation section 1102 is configured to rotate the rotary piston assembly 1110
in a second direction substantially opposite the first direction, e.g.,
counter-
clockwise.
[0099] The first actuation section 1101 of example actuator 1100 includes
a
collection of rotary pistons 812, and the second actuation section 1102
includes a collection of rotary pistons 822. By implementing individual rotary
pistons 812, 822 at various longitudinal positions along the rotary piston
assembly 1110, a range of rotary travel similar to the actuator 800 may be
achieved. In some embodiments, the actuator 1100 can rotate the rotor shaft
1110 about 60 degrees total.
[00100] In some embodiments, the use of the collection of rotary pistons 812
may provide mechanical advantages in some applications. For example, the
use of multiple rotary pistons 812 may reduce stress or deflection of the
rotary
piston assembly, may reduce wear of the seal assemblies, or may provide
more degrees of freedom. In another example, providing partitions, e.g.,
webbing, between chambers can add strength to the pressure chamber
assembly 1120 and can reduce bowing out of the pressure chamber assembly
1120 under high pressure. In some embodiments, placement of an end tab on
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the rotor shaft assembly 1110 can reduce cantilever effects experienced by the
actuator 800 while under load, e.g., less stress or bending.
[00101] FIGs. 12-14 are perspective and cross-sectional views of another
example rotary piston-type actuator 1200. The actuator 1200 includes a rotary
piston assembly 1210, a first actuation section 1201, and a second actuation
section 1202.
[00102] The rotary piston assembly 1210 of example actuator 1200 includes
a rotor shaft 1212, a collection of rotor arms 1214, and a collection of dual
rotary pistons 1216. Each of the dual rotary pistons 1216 includes a connector
io section 1218 a piston end 1220a and a piston end 1220b. The piston ends
1220a-1220b are arcuate in shape, and are oriented opposite to each other in
a generally semicircular arrangement, and are joined at the connector section
1218. A bore 1222 is formed in the connector section 1218 and is oriented
substantially parallel to the axis of the semicircle formed by the piston ends
1220a-1220b. The bore 1222 is sized to accommodate a connector pin (not
shown) that is passed through the bore 1222 and a collection of bores 1224
formed in the rotor arms 1213 to secure each of the dual rotary pistons 1216
to
the rotor shaft 1212.
[00103] The first actuation section 1201 of example actuator 1200 includes a
first pressure chamber assembly 1250a, and the second actuation section
1202 includes a second pressure chamber assembly 1250b. The first
pressure chamber assembly 1250a includes a collection of pressure chambers
1252a formed as arcuate cavities in the first pressure chamber assembly
1250a. The second pressure chamber assembly 1250b includes a collection
of pressure chambers 1252b formed as arcuate cavities in the first pressure
chamber assembly 1250b. When the pressure chamber assemblies 1250a-
1250b are assembled into the actuator 1200, each of the pressure chambers
1252a lies generally in a plane with a corresponding one of the pressure
chambers 1252b, such that a pressure chamber 1252a and a pressure
chamber 1252b occupy two semicircular regions about a central axis. A
semicircular bore 1253a and a semicircular bore 1253b substantially align to
accommodate the rotor shaft 1212.
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[00104] Each of the pressure chambers 1252a-1252b of example actuator
1200 includes an open end 1254 and a seal assembly 1256. The open ends
1254 are formed to accommodate the insertion of the piston ends 1220a-
1220b. The seal assemblies 1256 contact the inner walls of the pressure
chambers 1252a-1252b and the outer surfaces of the piston ends 1220a-
1220b to form a fluidic seal.
[00105] The rotary piston assembly 1210 of example actuator 1200 can be
assembled by aligning the bores 1222 of the dual rotary pistons 1216 with the
bores 1224 of the rotor arms 1214. The connector pin (not shown) is passed
io through the bores 1222 and 1224 and secured longitudinally by retaining
fasteners.
[00106] The example actuator 1200 can be assembled by positioning the
rotor shaft 1212 substantially adjacent to the semicircular bore 1253a and
rotating it to insert the piston ends 1220a substantially fully into the
pressure
chambers 1252a. The second pressure chamber 1252b is positioned adjacent
to the first pressure chamber 1252a such that the semicircular bore 1253b is
positioned substantially adjacent to the rotor shaft 1212. The rotary piston
assembly 1210 is then rotated to partly insert the piston ends 1220b into the
pressure chambers 1252b. An end cap 1260 is fastened to the longitudinal
ends 1262a of the pressure chambers 1252a-1252b. A second end cap (not
shown) is fastened to the longitudinal ends 1262b of the pressure chambers
1252a-1252b. The end caps substantially maintain the positions of the rotary
piston assembly 1210 and the pressure chambers 1252a-1252b relative to
each other. In some embodiments, the actuator 1200 can provide about 90
degrees of total rotational stroke.
[00107] In operation, pressurized fluid is applied to the pressure chambers
1252a of example actuator 1200 to rotate the rotary piston assembly 1210 in a
first direction, e.g., clockwise. Pressurized fluid is applied to the pressure
chambers 1252b to rotate the rotary piston assembly 1210 in a second
direction, e.g., counter-clockwise.
[00108] FIGs. 15 and 16 are perspective and cross-sectional views of
another example rotary piston-type actuator 1500 that includes another
example rotary piston assembly 1501. In some embodiments, the assembly
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1501 can be an alternative embodiment of the rotary piston assembly 200 of
FIG. 2.
[00109] The assembly 1501 of example actuator 1500 includes a rotor shaft
1510 connected to a collection of rotary pistons 1520a and a collection of
rotary pistons 1520b by a collection of rotor arms 1530 and one or more
connector pins (not shown). The rotary pistons 1520a and 1520b are arranged
along the rotor shaft 1510 in a generally alternating pattern, e.g., one
rotary
piston 1520a, one rotary piston 1520b, one rotary piston 1520a, one rotary
piston 1520b. In some embodiments, the rotary pistons 1520a and 1520b may
io be arranged along the rotor shaft 1510 in a generally intermeshed
pattern,
e.g., one rotary piston 1520a and one rotary piston 1520b rotationally
parallel
to each other, with connector portions formed to be arranged side-by-side or
with the connector portion of rotary piston 1520a formed to one or more male
protrusions and/or one or more female recesses to accommodate one or more
corresponding male protrusions and/or one or more corresponding female
recesses formed in the connector portion of the rotary piston 1520b.
[00110] Referring to FIG. 16, a pressure chamber assembly 1550 of
example actuator 1500 includes a collection of arcuate pressure chambers
1555a and a collection of arcuate pressure chambers 1555b. The pressure
chambers 1555a and 1555b are arranged in a generally alternating pattern
corresponding to the alternating pattern of the rotary pistons 1520a-1520b.
The rotary pistons 1520a-1520b extend partly into the pressure chambers
1555a-1555b. A seal assembly 1560 is positioned about an open end 1565 of
each of the pressure chambers 1555a-1555b to form fluidic seals between the
inner walls of the pressure chambers 1555a-1555b and the rotary pistons
1520a-1520b.
[00111] In use, pressurized fluid can be alternatingly provided to the
pressure chambers 1555a and 1555b of example actuator 1500 to urge the
rotary piston assembly 1501 to rotate partly clockwise and counterclockwise.
In some embodiments, the actuator 1500 can rotate the rotor shaft 1510 about
92 degrees total.
[00112] FIGs. 17 and 18 are perspective and cross-sectional views of
another example rotary piston-type actuator 1700 that includes another
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example rotary piston assembly 1701. In some embodiments, the assembly
1701 can be an alternative embodiment of the rotary piston assembly 200 of
FIG. 2 or the assembly 1200 of FIG. 12.
[00113] The assembly 1701 of example actuator 1700 includes a rotor shaft
1710 connected to a collection of rotary pistons 1720a by a collection of
rotor
arms 1730a and one or more connector pins 1732. The rotor shaft 1710 is
also connected to a collection of rotary pistons 1720b by a collection of
rotor
arms 1730b and one or more connector pins 1732. The rotary pistons 1720a
and 1720b are arranged along the rotor shaft 1710 in a generally opposing,
io symmetrical pattern, e.g., one rotary piston 1720a is paired with one
rotary
piston 1720b at various positions along the length of the assembly 1701.
[00114] Referring to FIG. 18, a pressure chamber assembly 1750 of
example actuator 1700 includes a collection of arcuate pressure chambers
1755a and a collection of arcuate pressure chambers 1755b. The pressure
chambers 1755a and 1755b are arranged in a generally opposing, symmetrical
pattern corresponding to the symmetrical arrangement of the rotary pistons
1720a-1720b. The rotary pistons 1720a-1720b extend partly into the pressure
chambers 1755a-1755b. A seal assembly 1760 is positioned about an open
end 1765 of each of the pressure chambers 1755a-1755b to form fluidic seals
between the inner walls of the pressure chambers 1755a-1755b and the rotary
pistons 1720a-1720b.
[00115] In use, pressurized fluid can be alternatingly provided to the
pressure chambers 1755a and 1755b of example actuator 1700 to urge the
rotary piston assembly 1701 to rotate partly clockwise and counterclockwise.
In some embodiments, the actuator 1700 can rotate the rotor shaft 1710 about
52 degrees total.
[00116] FIGs. 19 and 20 are perspective and cross-sectional views of
another example rotary piston-type actuator 1900. Whereas the actuators
described previously, e.g., the example actuator 100 of FIG. 1, are generally
elongated and cylindrical, the actuator 1900 is comparatively flatter and more
disk-shaped.
[00117] Referring to FIG. 19, a perspective view of the example rotary
piston-type actuator 1900 is shown. The actuator 1900 includes a rotary
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piston assembly 1910 and a pressure chamber assembly 1920. The rotary
piston assembly 1910 includes a rotor shaft 1912. A collection of rotor arms
1914 extend radially from the rotor shaft 1912, the distal end of each rotor
arm
1914 including a bore 1916 aligned substantially parallel with the axis of the
rotor shaft 1912 and sized to accommodate one of a collection of connector
pins 1918.
[00118] The rotary piston assembly 1910 of example actuator 1900 includes
a pair of rotary pistons 1930 arranged substantially symmetrically opposite
each other across the rotor shaft 1912. In the example of the actuator 1900,
io the rotary pistons 1930 are both oriented in the same rotational
direction, e.g.,
the rotary pistons 1930 cooperatively push in the same rotational direction.
In
some embodiments, a return force may be provided to rotate the rotary piston
assembly 1910 in the direction of the rotary pistons 1930. For example, the
rotor shaft 1912 may be coupled to a load that resists the forces provided by
the rotary pistons 1930, such as a load under gravitational pull, a load
exposed
to wind or water resistance, a return spring, or any other appropriate load
that
can rotate the rotary piston assembly. In some embodiments, the actuator
1900 can include a pressurizable outer housing over the pressure chamber
assembly 1920 to provide a back-drive operation , e.g., similar to the
function
provided by the outer housing 450 in FIG. 4. In some embodiments, the
actuator 1900 can be rotationally coupled to an oppositely oriented actuator
1900 that can provide a back-drive operation.
[00119] In some embodiments, the rotary pistons 1930 can be oriented in
opposite rotational directions, e.g., the rotary pistons 1930 can oppose each
other push in the opposite rotational directions to provide bidirectional
motion
control. In some embodiments, the actuator 100 can rotate the rotor shaft
about 60 degrees total.
[00120] Each of the rotary pistons 1930 of example actuator 1900 includes a
piston end 1932 and one or more connector arms 1934. The piston end 1932
is formed to have a generally semi-circular body having a substantially smooth
surface. Each of the connector arms 1934 includes a bore 1936 (see FIGs.
21B and 21C) substantially aligned with the axis of the semi-circular body of
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the piston end 1932 and sized to accommodate one of the connector pins
1918.
[00121] Each of the rotary pistons 1930 of example actuator 1900 is
assembled to the rotor shaft 1912 by aligning the connector arms 1934 with
the rotor arms 1914 such that the bores 1916 of the rotor arms 1914 align with
the bores 1936. The connector pins 1918 are inserted through the aligned
bores to create hinged connections between the pistons 1930 and the rotor
shaft 1912. Each connector pin 1916 is slightly longer than the aligned bores.
About the circumferential periphery of each end of each connector pin 1916
io that extends beyond the aligned bores is a circumferential recess (not
shown)
that can accommodate a retaining fastener (not shown), e.g., a snap ring or
spiral ring.
[00122] Referring now to FIG. 20 a cross-sectional view of the example
rotary piston-type actuator 1900 is shown. The illustrated example shows the
rotary pistons 1930 partly inserted into a corresponding pressure chamber
1960 formed as an arcuate cavity in the pressure chamber assembly 1920.
[00123] Each pressure chamber 1960 of example actuator 1900 includes a
seal assembly 1962 about the interior surface of the pressure chamber 1960 at
an open end 1964. In some embodiments, the seal assembly 1962 can be a
circular or semi-circular sealing geometry retained on all sides in a standard
seal groove.
[00124] When the rotary pistons 1930 of example actuator 1900 are inserted
through the open ends 1964, each of the seal assemblies 1962 contacts the
interior surface of the pressure chamber 1960 and the substantially smooth
surface of the piston end 1932 to form a substantially pressure-sealed region
within the pressure chamber 1960. Each of the pressure chambers 1960 each
include a fluid port (not shown) formed through the pressure chamber
assembly 1920, through with pressurized fluid may flow.
[00125] Upon introduction of pressurized fluid, e.g., hydraulic oil, water,
air,
gas, into the pressure chambers 1960 of example actuator 1900, the pressure
differential between the interior of the pressure chambers 1960 and the
ambient conditions outside the pressure chambers 1960 causes the piston
ends 1932 to be urged outward from the pressure chambers 1960. As the
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piston ends 1932 are urged outward, the pistons 1930 urge the rotary piston
assembly 1910 to rotate.
[00126] In the illustrated example actuator 1900, each of the rotary pistons
1930 includes a cavity 1966. FIGs. 21A-21C provide additional cross-sectional
and perspective views of one of the rotary pistons 1930. Referring to FIG.
21A,
a cross-section the rotary piston 1930, taken across a section of the piston
end
1932 is shown. The cavity 1966 is formed within the piston end 1932.
Referring to FIG. 21B, the connector arm 1934 and the bore 1936 is shown in
perspective. FIG. 21C features a perspective view of the cavity 1966.
[00127] In some embodiments, the cavity 1966 may be omitted. For
example, the piston end 1932 may be solid in cross-section. In some
embodiments, the cavity 1966 may be formed to reduce the mass of the rotary
piston 1930 and the mass of the actuator 1900. For example, the actuator
1900 may be implemented in an aircraft application, where weight may play a
role in actuator selection. In some embodiments, the cavity 1966 may reduce
wear on seal assemblies, such as the seal assembly 320 of FIG. 3. For
example, by reducing the mass of the rotary piston 1930, the amount of force
the piston end 1932 exerts upon the corresponding seal assembly may be
reduced when the mass of the rotary piston is accelerated, e.g., by gravity or
G-forces.
[00128] In some embodiments, the cavity 1966 may be substantially hollow
in cross-section, and include one or more structural members, e.g., webs,
within the hollow space. For example, structural cross-members may extend
across the cavity of a hollow piston to reduce the amount by which the piston
may distort, e.g., bowing out, when exposed to a high pressure differential
across the seal assembly.
[00129] FIGs. 22 and 23 illustrate a comparison of two example rotor shaft
embodiments. FIG. 22 is a perspective view of an example rotary piston-type
actuator 2200. In some embodiments, the example actuator 2200 can be the
example actuator 1900.
[00130] The example actuator 2200 includes a pressure chamber assembly
2210 and a rotary piston assembly 2220. The rotary piston assembly 2220
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includes at least one rotary piston 2222 and one or more rotor arms 2224. The
rotor arms 2224 extend radially from a rotor shaft 2230.
[00131] The rotor shaft 2230 of example actuator includes an output section
2232 and an output section 2234 that extend longitudinally from the pressure
chamber assembly 2210. The output sections 2232-2234 include a collection
of splines 2236 extending radially from the circumferential periphery of the
output sections 2232-2234. In some implementations, the output section 2232
and/or 2234 may be inserted into a correspondingly formed splined assembly
to rotationally couple the rotor shaft 2230 to other mechanisms. For example,
by rotationally coupling the output section 2232 and/or 2234 to an external
assembly, the rotation of the rotary piston assembly 2220 may be transferred
to urge the rotation of the external assembly.
[00132] FIG. 23 is a perspective view of another example rotary piston-type
actuator 2300. The actuator 2300 includes the pressure chamber assembly
2210 and a rotary piston assembly 2320. The rotary piston assembly 2320
includes at least one of the rotary pistons 2222 and one or more of the rotor
arms 2224. The rotor arms 2224 extend radially from a rotor shaft 2330.
[00133] The rotor shaft 2330 of example actuator 2300 includes a bore 2332
formed longitudinally along the axis of the rotor shaft 2330. The rotor shaft
2330 includes a collection of splines 2336 extending radially inward from the
circumferential periphery of the bore 2332. In some embodiments, a
correspondingly formed splined assembly may be inserted into the bore 2332
to rotationally couple the rotor shaft 2330 to other mechanisms.
[00134] FIG. 24 is a perspective view of another example rotary piston 2400.
In some embodiments, the rotary piston 2400 can be the rotary piston 250,
260, 414, 712, 812, 822, 1530a, 1530b, 1730a, 1730b, 1930 or 2222.
[00135] The example rotary piston 2400 includes a piston end 2410 and a
connector section 2420. The connector section 2420 includes a bore 2430
formed to accommodate a connector pin, e.g., the connector pin 214.
[00136] The piston end 2410 of example actuator 2400 includes an end
taper 2440. The end taper 2440 is formed about the periphery of a terminal
end 2450 of the piston end 2410. The end taper 2440 is formed at a radially
inward angle starting at the outer periphery of the piston end 2410 and ending
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at the terminal end 2450. In some implementations, the end taper 2440 can
be formed to ease the process of inserting the rotary piston 2400 into a
pressure chamber, e.g., the pressure chamber 310.
[00137] The piston end 2410 of example actuator 2400 is substantially
smooth. In some embodiments, the smooth surface of the piston end 2410
can provide a surface that can be contacted by a seal assembly. For example,
the seal assembly 320 can contact the smooth surface of the piston end 2410
to form part of a fluidic seal, reducing the need to form a smooth,
fluidically
sealable surface on the interior walls of the pressure chamber 310.
[00138] In the illustrated example, the rotary piston 2400 is shown as having
a generally solid circular cross-section, whereas the rotary pistons piston
250,
260, 414, 712, 812, 822, 1530a, 1530b, 1730a, 1730b, 1930 or 2222 have
been illustrated as having various generally rectangular, elliptical, and
other
shapes, both solid and hollow, in cross section. In some embodiments, the
cross sectional dimensions of the rotary piston 2400, as generally indicated
by
the arrows 2491 and 2492, can be adapted to any appropriate shape, e.g.,
square, rectangular, ovoid, elliptical, circular, and other shapes, both solid
and
hollow, in cross section.. In some embodiments, the arc of the rotary piston
2400, as generally indicated by the angle 2493, can be adapted to any
appropriate length. In some embodiments, the radius of the rotary piston
2400, as generally indicated by the line 2494, can be adapted to any
appropriate radius. In some embodiments, the piston end 2410 can be
substantially solid, substantially hollow, or can include any appropriate
hollow
formation. In some embodiments, any of the previously mentioned forms of
the piston end 2410 can also be used as the piston ends 1220a and/or 1220b
of the dual rotary pistons 1216 of FIG. 12.
[00139] FIG. 25 is a flow diagram of an example process 2500 for
performing rotary actuation. In some implementations, the process 2500 can
be performed by the rotary piston-type actuators 100, 400, 700, 800, 1200,
1500, 1700, 1900, 2200, 2300, and/or 2600 which will be discussed in the
descriptions of FIGs. 26-28.
[00140] At 2510, a rotary actuator is provided. The rotary actuator of
example actuator 2500 includes a first housing defining a first arcuate
chamber
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including a first cavity, a first fluid port in fluid communication with the
first
cavity, an open end, and a first seal disposed about an interior surface of
the
open end, a rotor assembly rotatably journaled in the first housing and
including a rotary output shaft and a first rotor arm extending radially
outward
from the rotary output shaft, an arcuate-shaped first piston disposed in the
first
housing for reciprocal movement in the first arcuate chamber through the open
end. The first seal, the first cavity, and the first piston define a first
pressure
chamber, and a first connector, coupling a first end of the first piston to
the first
rotor arm. For example, the actuator 100 includes the components of the
io pressure chamber assembly 300 and the rotary piston assembly 200
included
in the actuation section 120.
[00141] At 2520, a pressurized fluid is applied to the first pressure chamber.
For example, pressurized fluid can be flowed through the fluid port 320 into
the
pressure chamber 310.
[00142] At 2530, the first piston is urged partially outward from the first
pressure chamber to urge rotation of the rotary output shaft in a first
direction.
For example, a volume of pressurized fluid flowed into the pressure chamber
310 will displace a similar volume of the rotary piston 260, causing the
rotary
piston 260 to be partly urged out of the pressure cavity 310, which in turn
will
cause the rotor shaft 210 to rotate clockwise.
[00143] At 2540, the rotary output shaft is rotated in a second direction
opposite that of the first direction. For example, the rotor shaft 210 can be
rotated counter-clockwise by an external force, such as another mechanism, a
torque-providing load, a return spring, or any other appropriate source of
rotational torque.
[00144] At 2550, the first piston is urged partially into the first pressure
chamber to urge pressurized fluid out the first fluid port. For example, the
rotary piston 260 can be pushed into the pressure chamber 310, and the
volume of the piston end 252 extending into the pressure chamber 310 will
displace a similar volume of fluid, causing it to flow out the fluid port 312.
[00145] In some embodiments, the example process 2500 can be used to
provide substantially constant power over stroke to a connected mechanism.
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For example, as the actuator 100 rotates, there may be substantially little
position-dependent variation in the torque delivered to a connected load.
[00146] In some embodiments, the first housing further defines a second
arcuate chamber comprising a second cavity, a second fluid port in fluid
communication with the second cavity, and a second seal disposed about an
interior surface of the open end, the rotor assembly also includes a second
rotor arm, the rotary actuator also includes an arcuate-shaped second piston
disposed in said housing for reciprocal movement in the second arcuate
chamber, wherein the second seal, the second cavity, and the second piston
io define a second pressure chamber, and a second connector coupling a
first
end of the second piston to the second rotor arm. For example, the actuator
100 includes the components of the pressure chamber assembly 300 and the
rotary piston assembly 200 included in the actuation section 110.
[00147] In some embodiments, the second piston can be oriented in the
same rotational direction as the first piston. For example, the two pistons
260
are oriented to operate cooperatively in the same rotational direction. In
some
embodiments, the second piston can be oriented in the opposite rotational
direction as the first piston. For example, the rotary pistons 250 are
oriented to
operate in the opposite rotational direction relative to the rotary pistons
260.
[00148] In some embodiments, the actuator can include a second housing
and disposed about the first housing and having a second fluid port, wherein
the first housing, the second housing, the seal, and the first piston define a
second pressure chamber. For example, the actuator 400 includes the outer
housing 450 that substantially surrounds the pressure chamber assembly 420.
Pressurized fluid in the bore 452 is separated from fluid in the pressure
chambers 422 by the seals 426.
[00149] In some implementations, rotating the rotary output shaft in a second
direction opposite that of the first direction can include applying
pressurized
fluid to the second pressure chamber, and urging the second piston partially
outward from the second pressure chamber to urge rotation of the rotary
output shaft in a second direction opposite from the first direction. For
example, pressurized fluid can be applied to the pressure chambers 310 of the
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first actuation section 110 to urge the rotary pistons 260 outward, causing
the
rotor shaft 210 to rotate counter-clockwise.
[00150] In some implementations, rotating the rotary output shaft in a second
direction opposite that of the first direction can include applying
pressurized
fluid to the second pressure chamber, and urging the first piston partially
into
the first pressure chamber to urge rotation of the rotary output shaft in a
second direction opposite from the first direction. For example, pressurized
fluid can be flowed into the bore 452 at a pressure higher than that of fluid
in
the pressure chambers 422, causing the rotary pistons 414 to move into the
io pressure chambers 422 and cause the rotor shaft 412 to rotate counter-
clockwise.
[00151] In some implementations, rotation of the rotary output shaft can urge
rotation of the housing. For example, the rotary output shaft 412 can be held
rotationally stationary and the housing 450 can be allowed to rotate, and
application of pressurized fluid in the pressure chambers 422 can urge the
rotary pistons 414 out of the pressure chambers 422, causing the housing 450
to rotate about the rotary output shaft 412.
[00152] FIGs. 26-28 show various views of the components of another
example rotary piston-type actuator 2600. In general, the actuator 2600 is
similar to the example actuator 100 of FIG. 1, except for the configuration of
the seal assemblies. Whereas the seal assembly 320 in the example actuator
100 remains substantially stationary relative to the pressure chamber 310 and
is in sliding contact with the surface of the rotary piston 250, in the
example
actuator 2600, the seal configuration is comparatively reversed as will be
described below.
[00153] Referring to FIG. 26, a perspective view of the example rotary
piston-type actuator 2600 is shown. The actuator 2600 includes a rotary
piston assembly 2700 and a pressure chamber assembly 2602. The actuator
2600 includes a first actuation section 2610 and a second actuation section
2620. In the example of actuator 2600, the first actuation section 2610 is
configured to rotate the rotary piston assembly 2700 in a first direction,
e.g.,
counter-clockwise, and the second actuation section 2620 is configured to
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rotate the rotary piston assembly 2700 in a second direction substantially
opposite the first direction, e.g., clockwise.
[00154] Referring now to FIG. 27, a perspective view of the example rotary
piston assembly 2700 is shown apart from the pressure chamber assembly
2602. The rotary piston assembly 2700 includes a rotor shaft 2710. A plurality
of rotor arms 2712 extend radially from the rotor shaft 2710, the distal end
of
each rotor arm 2712 including a bore (not shown) substantially aligned with
the
axis of the rotor shaft 2710 and sized to accommodate one of a collection of
connector pins 2714.
[00155] As shown in FIG. 27, the first actuation section 2710 of example
rotary piston assembly 2700 includes a pair of rotary pistons 2750, and the
second actuation section 2720 includes a pair of rotary pistons 2760. While
the example actuator 2600 includes two pairs of the rotary pistons 2750, 2760,
other embodiments can include greater and/or lesser numbers of cooperative
and opposing rotary pistons.
[00156] In the example rotary piston assembly shown in FIG. 27, each of the
rotary pistons 2750, 2760 includes a piston end 2752 and one or more
connector arms 2754. The piston end 252 is formed to have a generally semi-
circular body having a substantially smooth surface. Each of the connector
arms 2754 includes a bore 2756 substantially aligned with the axis of the semi-
circular body of the piston end 2752 and sized to accommodate one of the
connector pins 2714.
[00157] In some implementations, each of the rotary pistons 2750, 2760
includes a seal assembly 2780 disposed about the outer periphery of the
piston ends 2752. In some implementations, the seal assembly 2780 can be a
circular or semi-circular sealing geometry retained on all sides in a standard
seal groove. In some implementations, commercially available reciprocating
piston or cylinder type seals can be used. For example, commercially available
seal types that may already be in use for linear hydraulic actuators flying on
current aircraft may demonstrate sufficient capability for linear load and
position holding applications. In some implementations, the sealing complexity
of the actuator 2600 may be reduced by using a standard, e.g., commercially
available, semi-circular, unidirectional seal designs generally used in linear
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hydraulic actuators. In some embodiments, the seal assembly 2780 can be a
one-piece seal.
[00158] FIG. 28 is a perspective cross-sectional view of the example rotary
piston-type actuator 2600. The illustrated example shows the rotary pistons
2760 inserted into a corresponding pressure chamber 2810 formed as an
arcuate cavity in the pressure chamber assembly 2602. The rotary pistons
2750 are also inserted into corresponding pressure chambers 2810, not visible
in this view.
[00159] In the example actuator 2600, when the rotary pistons 2750, 2760
io are each inserted through an open end 2830 of each pressure chamber
2810,
each seal assembly 2780 contacts the outer periphery of the piston end 2760
and the substantially smooth interior surface of the pressure chamber 2810 to
form a substantially pressure-sealed region within the pressure chamber 2810.
[00160] In some embodiments, the seal 2780 can act as a bearing. For
example, the seal 2780 may provide support for the piston 2750, 2760 as it
moves in and out of the pressure chamber 310.
[00161] FIGs. 29A-29E are various views of another example rotary piston-
type actuator 2900 with a central actuation assembly 2960. For a brief
description of each drawing see the brief description of each of these
drawings
included at the beginning of the Description of the Drawings section of this
document.
[00162] In general, the example rotary piston-type actuator 2900 is
substantially similar to the example rotary piston-type actuator 1200 of
FIGs.12-14, where the example rotary piston-type actuator 2900 also includes
a central actuation assembly 2960 and a central mounting assembly 2980.
Although the example rotary piston-type actuator 2900 is illustrated and
described as modification of the example rotary piston-type actuator 1200, in
some embodiments the example rotary piston-type actuator 2900 can
implement features of any of the example rotary piston-type actuators 100,
400, 700, 800, 1200, 1500, 1700, 1900, 2200, 2300, and/or 2600 in a design
that also implements the central actuation assembly 2960 and/or the central
mounting assembly 2980.
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[00163] The actuator 2900 includes a rotary actuator assembly 2910, a first
actuation section 2901 and a second actuation section 2902. The rotary piston
assembly 2910 includes a rotor shaft 2912, a collection of rotor arms 2914,
and the collection of dual rotary pistons, e.g., the dual rotary pistons 1216
of
FIGs. 12-14.
[00164] The first actuation section 2901 of example actuator 2900 includes a
first pressure chamber assembly 2950a, and the second actuation section
2902 includes a second pressure chamber assembly 2950b. The first
pressure chamber assembly 2950a includes a collection of pressure
chambers, e.g., the pressure chambers 1252a of FIGs. 12-14, formed as
arcuate cavities in the first pressure chamber assembly 2950a. The second
pressure chamber assembly 2950b includes a collection of pressure
chambers, e.g., the pressure chambers 1252b of FIGs. 12-14, formed as
arcuate cavities in the second pressure chamber assembly 2950b. A
semicircular bore 2953 in the housing accommodates the rotor shaft 2912.
[00165] The central mounting assembly 2980 is formed as a radially
projected portion 2981 of a housing of the second pressure chamber assembly
2950b. The central mounting assembly 2980 provides a mounting point for
removably affixing the example rotary piston-type actuator 2900 to an external
surface, e.g., an aircraft frame. A collection of holes 2982 formed in the
radially projected section 2981 accommodate the insertion of a collection of
fasteners 2984, e.g., bolts, to removably affix the central mounting assembly
2980 to an external mounting feature 2990, e.g., a mounting point (bracket) on
an aircraft frame.
[00166] The central actuation assembly 2960 includes a radial recess 2961
formed in a portion of an external surface of a housing of the first and the
second actuation sections 2901, 2902 at a midpoint along a longitudinal axis
AA to the example rotary piston-type actuator 2900. An external mounting
bracket 2970 that may be adapted for attachment to an external mounting
feature on a member to be actuated, (e.g., aircraft flight control surfaces)
is
connected to an actuation arm 2962. The actuation arm 2962 extends through
the recess 2961 and is removably attached to a central mount point 2964
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formed in an external surface at a midpoint of the longitudinal axis of the
rotor
shaft 2912.
[00167] Referring more specifically to FIGs. 29D and 29E now, the example
rotary piston-type actuator 2900 is shown in cutaway end and perspective
views taken though a midpoint of the central actuation assembly 2960 and the
central mounting assembly 2980 at the recess 2961. The actuation arm 2962
extends into the recess 2961 to contact the central mount point 2964 of the
rotor shaft 2912. The actuation arm 2962 is removably connected to the
central mount point 2964 by a fastener 2966, e.g., bolt, that is passed
through
io a pair of holes 2968 formed in the actuation arm 2962 and a hole 2965
formed
through the central mount point 2964. A collection of holes 2969 are formed
in a radially outward end of the actuation arm 2962. A collection of fasteners
2972, e.g., bolts, are passed through the holes 2969 and corresponding holes
(not shown) formed in an external mounting feature (bracket) 2970. As
mentioned above, the central actuation assembly 2960 connects the example
rotary piston actuator 2900 to the external mounting feature 2970 to transfer
rotational motion of the rotor assembly 2910 to equipment to be moved
(actuated), e.g., aircraft flight control surfaces.
[00168] In some embodiments, one of the central actuation assembly 2960
or the central mounting assembly 2980 can be used in combination with
features of any of the example rotary piston-type actuators 100, 400, 700,
800,
1200, 1500, 1700, 1900, 2200, 2300, and/or 2600. For example, the example
rotary piston-type actuator 2900 may be mounted to a stationary surface
through the central mounting assembly 2980, and provide actuation at one or
both ends of the rotor shaft assembly 2910. In another example, the example
rotary piston assembly 2900 may be mounted to a stationary surface through
non-central mounting points, and provide actuation at the central actuation
assembly 2960.
[00169] FIGs. 30A-30E are various views of an example rotary actuator 3000
with a central actuation assembly 3060. For a brief description of each
drawing
see the brief description of each of these drawings included at the beginning
of
the Description of the Drawings section of this document.
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[00170] In general, the example rotary actuator 3000 is substantially similar
to the rotary piston-type actuator 2900 of FIGs. 29A-29E, where the example
rotary actuator 3000 also includes a central actuation assembly 3060 and a
central mounting assembly 3080. In some embodiments, the example rotary
actuator 3000 can be a modification of the example rotary piston-type actuator
2900 in which rotational action can be performed by a mechanism other than a
rotary piston-type actuator. For example, the example rotary actuator 3000
can be include a rotary vane type actuator, a rotary fluid type actuator, an
electromechanical actuator, a linear-to-rotary motion actuator, or
combinations
io of these or any other appropriate rotary actuator. Although the example
rotary
actuator 3000 is illustrated and described as modification of the example
rotary
piston-type actuator 2900, in some embodiments the example rotary actuator
3000 can implement features of any of the example rotary piston-type
actuators 100, 400, 700, 800, 1200, 1500, 1700, 1900, 2200, 2300, 2600
and/or 2900 in a design that also implements the central actuation assembly
3060 and/or the central mounting assembly 3080.
[00171] The actuator 3000 includes a rotary actuator section 3010a and a
rotary actuator section 3010b. In some embodiments, the rotary actuator
sections 3010a and 3010b can be rotary vane type actuators, a rotary fluid
type actuators, electromechanical actuators, a linear-to-rotary motion
actuators, or combinations of these or any other appropriate rotary actuators.
The rotary actuator section 3010a includes a housing 3050a, and the rotary
actuator section 3010b includes a housing 3050b. A rotor shaft 3012a runs
along the longitudinal axis of the rotary actuator section 3010a, and a rotor
shaft 3012b runs along the longitudinal axis of the rotary actuator section
3010b.
[00172] The central mounting assembly 3080 is formed as a radially
projected portion 3081 of the housings 3050a and 3050b. The central
mounting assembly 3080 provides a mounting point for removably affixing the
example rotary actuator 3000 to an external surface or an external structural
member, e.g., an aircraft frame, an aircraft control surface. A collection of
holes 3082 formed in the radially projected section 3081 accommodate the
insertion of a collection of fasteners (not shown), e.g., bolts, to removably
affix
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the central mounting assembly 3080 to an external mounting feature, e.g., the
external mounting feature 2090 of FIG. 29, a mounting point (bracket) on an
aircraft frame or control surface.
[00173] The central actuation assembly 3060 includes a radial recess 3061
formed in a portion of an external surfaces of the housings 3050a, 3050b at a
midpoint along a longitudinal axis AA to the example rotary actuator 3000. In
some implementations, an external mounting bracket, such as the external
mounting bracket 2970, may be adapted for attachment to an external
mounting feature of a structural member or a member to be actuated, (e.g.,
io aircraft flight control surfaces) can be connected to an actuation arm
3062. An
actuation arm, such as the actuation arm 2962, can extend through the recess
3061 and can be removably attached to a central mount point 3064 formed in
an external surface at a midpoint of the longitudinal axis of the rotor shafts
3012a and 3012b.
[00174] Referring more specifically to FIGs. 30D and 30E now, the example
rotary piston-type actuator 3000 is shown in end and cutaway perspective
views taken though a midpoint of the central actuation assembly 3060 and the
central mounting assembly 3080 at the recess 3061. The actuation arm (not
shown) can extend into the recess 3061 to contact the central mount point
3064 of the rotor shafts 3012a, 3012b. The actuation arm can be removably
connected to the central mount point 3064 by a fastener, e.g., bolt, that can
be
passed through a pair of holes (e.g. the holes 2968 formed in the actuation
arm 2962) and a hole 3065 formed through the central mount point 3064.
Similarly to as was discussed in the description of the rotary piston-type
actuator 2900 and the central actuation assembly 2960, the central actuation
assembly 3060 connects the example rotary actuator 3000 to an external
mounting feature or structural member to impart rotational motion of the
actuator sections 3010a, 3010b to equipment to be moved (actuated), e.g.,
aircraft flight control surfaces, relative to structural members, e.g.,
aircraft
frames.
[00175] In some embodiments, one of the central actuation assembly 3060
or the central mounting assembly 3080 can be used in combination with
features of any of the example rotary piston-type actuators 100, 400, 700,
800,
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1200, 1500, 1700, 1900, 2200, 2300, 2600 and/or 2900. For example, the
example rotary actuator 3000 may be mounted to a stationary surface through
the central mounting assembly 3080, and provide actuation at one or both
ends of the rotor shafts 3012a, 3012b. In another example, the example rotary
actuator 3000 may be mounted to a stationary surface through non-central
mounting points, and provide actuation at the central actuation assembly 3060.
In another example, the rotary actuator 3000 may be mounted to a stationary
surface through the central mount point 3064, and provide actuation at the
central mounting assembly 3080.
[00176] FIGs. 31A-31E are various views of an example rotary actuator 3100
with a central actuation assembly 3160. For a brief description of each
drawing
see the brief description of each of these drawings included at the beginning
of
the Description of the Drawings section of this document.
[00177] In general, the example rotary actuator 3100 is substantially similar
to the rotary actuator 3000 of FIGs. 30A-30E, where the example rotary
actuator 3100 also includes a central actuation assembly 3160 and a central
mounting assembly 3180. In some embodiments, the example rotary actuator
3100 can be a modification of the example rotary piston-type actuator 3000 in
which rotational action can be performed by a mechanism other than a rotary
fluid actuator. The example rotary actuator 3100 is an an electromechanical
actuator. Although the example rotary actuator 3100 is illustrated and
described as modification of the example rotary actuator 3000, in some
embodiments the example rotary actuator 3100 can implement features of any
of the example rotary piston-type actuators 100, 400, 700, 800, 1200, 1500,
1700, 1900, 2200, 2300, 2600 and/or 2900 and/or the rotary actuator 3000 in a
design that also implements the central actuation assembly 3160 and/or the
central mounting assembly 3180.
[00178] The actuator 3100 includes a rotary actuator section 3110a and a
rotary actuator section 3110b. In some embodiments, the rotary actuator
sections 3110a and 3110b can be electromechanical actuators. The rotary
actuator section 3110a includes a housing 3150a, and the rotary actuator
section 3110b includes a housing 3150b. A rotor shaft 3112a runs along the
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longitudinal axis of the rotary actuator section 3110a, and a rotor shaft
3112b
runs along the longitudinal axis of the rotary actuator section 3110b.
[00179] The central mounting assembly 3180 is formed as a radially
projected portion 3181 of the housings 3150a and 3150b. The central
mounting assembly 3180 provides a mounting point for removably affixing the
example rotary actuator 3100 to an external surface or an external structural
member, e.g., an aircraft frame, an aircraft control surface. A collection of
holes 3182 formed in the radially projected section 3181 accommodate the
insertion of a collection of fasteners (not shown), e.g., bolts, to removably
affix
io the central mounting assembly 3180 to an external mounting feature,
e.g., the
external mounting feature 2090 of FIG. 29, a mounting point (bracket) on an
aircraft frame or control surface.
[00180] The central actuation assembly 3160 includes a radial recess 3161
formed in a portion of an external surfaces of the housings 3150a, 3150b at a
midpoint along a longitudinal axis AA to the example rotary actuator 3100. In
some implementations, an external mounting bracket, such as the external
mounting bracket 2970, may be adapted for attachment to an external
mounting feature of a structural member or a member to be actuated, (e.g.,
aircraft flight control surfaces) can be connected to an actuation arm 3162.
An
actuation arm, such as the actuation arm 2962, can extend through the recess
3161 and can be removably attached to a central mount point 3164 formed in
an external surface at a midpoint of the longitudinal axis of the rotor shafts
3112a and 3112b.
[00181] Referring more specifically to FIGs. 31D and 31E now, the example
rotary piston-type actuator 3100 is shown in end and cutaway perspective
views taken though a midpoint of the central actuation assembly 3160 and the
central mounting assembly 3080 at the recess 3161. The actuation arm (not
shown) can extend into the recess 3161 to contact the central mount point
3164 of the rotor shafts 3112a, 3112b. The actuation arm can be removably
connected to the central mount point 3164 by a fastener, e.g., bolt, that can
be
passed through a pair of holes (e.g. the holes 2968 formed in the actuation
arm 2962) and a hole 3165 formed through the central mount point 3164.
Similarly to as was discussed in the description of the rotary piston-type
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actuator 2900 and the central actuation assembly 2960, the central actuation
assembly 3160 connects the example rotary actuator 3100 to an external
mounting feature or structural member to impart rotational motion of the
actuator sections 3110a, 3110b to equipment to be moved (actuated), e.g.,
aircraft flight control surfaces, relative to structural members, e.g.,
aircraft
frames.
[00182] In some embodiments, one of the central actuation assembly 3160
or the central mounting assembly 3180 can be used in combination with
features of any of the example rotary piston-type actuators 100, 400, 700,
800,
1200, 1500, 1700, 1900, 2200, 2300, 2600 and/or 2900 and/or the rotary
actuator 3000. For example, the example rotary actuator 3100 may be
mounted to a stationary surface through the central mounting assembly 3180,
and provide actuation at one or both ends of the rotor shafts 3112a, 3112b. In
another example, the example rotary actuator 3100 may be mounted to a
stationary surface through non-central mounting points, and provide actuation
at the central actuation assembly 3160. In another example, the rotary
actuator 3100 may be mounted to a stationary surface through the central
mount point 3164, and provide actuation at the central mounting assembly
3180.
[00183] FIG. 32 is an exploded perspective view of another example
pressure chamber assembly 3200. In some embodiments, features of the
pressure chamber assembly 3200 can be used with any of the actuators 400,
800, 1200, 1500, 1750, 1900, 2200, 2300, and 2600. The pressure chamber
assembly 3200 includes a housing 3210, a modular piston housing 3250a, and
a modular piston housing 3250b. The housing 3210 includes a central
longitudinal cavity 3212. The central longitudinal cavity 3212 is formed to
accommodate a rotor shaft (not shown) such as the rotor shaft 210 of the
rotary piston assembly 200 of FIG. 2.
[00184] The modular piston housing 3250a of example pressure chamber
assembly 3200 is an arcuate-shaped assembly that includes a collection of
pressure chambers 3252a formed as arcuate cavities in the modular piston
housing 3250a. Similarly, the modular piston housing 3250b is also an
arcuate-shaped assembly that includes a collection of pressure chambers
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3252b formed as arcuate cavities in the modular piston housing 3250b. In the
illustrated example, the modular piston housing 3250b mirrors the arcuate
shape of the modular piston housing 3250a. The pressure chambers 3252a,
3252b are formed to accommodate rotary pistons (not shown) such as rotary
pistons 250. In some implementations, the modular piston housings 3250a,
3250b can be formed as unitary piston housings. For example, the modular
piston housings 3250a, 3250b may each be machined, extruded, or otherwise
formed without forming seams within the pressure chambers 3251a, 3252b.
[00185] In the assembled form of the example pressure chamber assembly
3200, the modular piston housings 3250a, 3250b are removably affixed to the
housing 3210. In some embodiments, the pressure chamber assembly 3200
can include radial apertures into which the modular piston housings 3250a,
3250b can be inserted. In some embodiments, the pressure chamber
assembly 3200 can include longitudinal apertures into which the modular
piston housings 3250a, 3250b can be inserted.
[00186] The modular piston housings 3250a, 3250b of example pressure
chamber assembly 3200 include a collection of bores 3254. In the assembled
form of the pressure chamber assembly 3200 the bores 3254 align with a
collection of bores 3256 formed in the housing 3210, a collection of fasteners
(not shown), e.g., bolts or screws, are passed through the bores 3256 and into
the bores 3254 to removably affix the modular piston housings 3250a, 3250b
to the housing 3210.
[00187] In some embodiments, modular piston housings 3250a, 3250b can
include a seal assembly about the interior surface of the pressure chambers
3252a, 3252b. In some embodiments, the seal assembly can be a circular or
semi-circular sealing geometry retained on all sides in a standard seal
groove.
In some embodiments, commercially available reciprocating piston or cylinder
type seals can be used. For example, commercially available seal types that
may already be in use for linear hydraulic actuators flying on current
aircraft
may demonstrate sufficient capability for linear load and position holding
applications. In some embodiments, the sealing complexity of the example
pressure chamber assembly 3200 may be reduced by using a standard, e.g.,
commercially available, semi-circular, unidirectional seal design generally
used
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in linear hydraulic actuators. In some embodiments, the seal assemblies can
be a one-piece seal. In some embodiments of the modular piston housings
3250a, 3250b, the seal assemblies may be included as part of the rotary
pistons. In some embodiments, the modular piston housings 3250a, 3250b
may include a wear member between the pistons and the pressure chambers
3252a, 3252b.
[00188] Each of the pressure chambers 3252a, 3252b of example pressure
chamber assembly 3200 may include a fluid port (not shown) formed through
the modular piston housings 3250a, 3250b, through which pressurized fluid
io may flow. Upon introduction of pressurized fluid (e.g., hydraulic oil,
water, air,
gas) into the pressure chambers 3252a, 3252b, the pressure differential
between the interior of the pressure chambers 3252a, 3252b and the ambient
conditions outside the pressure chambers 3252a, 3252b can cause ends of
the pistons to be urged outward from the pressure chambers 3252a, 3252b.
As the piston ends are urged outward, the pistons urge a rotary piston
assembly, such as the rotary piston assembly 200, to rotate.
[00189] In some embodiments, the modular piston housings 3250a, 3250b
may include the central longitudinal cavity 3212 and other features of the
housing 3210. In some embodiments, the modular piston housings 3250a,
3250b may be removably affixed to each other. For example, the modular
piston housings 3250a, 3250b may be bolted, screwed, clamped, welded,
pinned, or otherwise directly or indirectly retained relative to each other
such
that the assembled combination provides the features of the housing 3210,
eliminating the need for the housing 3210.
[00190] FIGs. 33A-33C are exploded and assembled perspective views of
another example rotary piston assembly 3300. In some embodiments,
features of the rotary piston assembly 3300 can be used with any of the rotary
piston assemblies 200, 700, 1100, 1501, 1701, and 2700, and/or with any of
the actuators 400, 800, 1200, 1500, 1750, 1900, 2200, 2300, 2600, 2900, and
3000. The rotary piston assembly 3300 includes a rotor shaft 3310. A plurality
of rotor arms 3312 extend radially from the rotor shaft 3310, the distal end
of
each rotor arm 3312 including a bore (not shown) substantially aligned with
the
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axis of the rotor shaft 3310 and sized to accommodate one of a collection of
connector pins 3314.
[00191] The example rotary piston assembly 3300 includes a pair of rotary
pistons 3350. While the example rotary piston assembly 3300 includes two of
the rotary pistons 3350, other embodiments can include greater and/or lesser
numbers of cooperative and opposing rotary pistons. Each of the rotary
pistons 3350 includes a piston end 3352 and one or more connector arms
3354. The piston end 3352 is formed to have a generally semi-circular body
having a substantially smooth surface. Each of the connector arms 3354
io includes a bore 3356 substantially aligned with the axis of the semi-
circular
body of the piston end 3352 and sized to accommodate one of the connector
pins 3314.
[00192] Each of the rotary pistons 3350 of the example rotary piston
assembly 3300 may be assembled to the rotor shaft 3310 by aligning the
connector arms 3354 with the rotor arms 3312 such that the bores (not shown)
of the rotor arms 3312 align with the bores 3365. The connector pins 3314
may then be inserted through the aligned bores to create connections between
the pistons 3350 and the rotor shaft 3310. As shown, each connector pin 3314
is slightly longer than the aligned bores. In the example assembly, about the
circumferential periphery of each end of each connector pin 3314 that extends
beyond the aligned bores is a circumferential recess (not shown) that can
accommodate a retaining fastener (not shown), e.g., a snap ring or spiral
ring.
[00193] The connections between the connector arms 3354 with the rotor
arms 3312, unlike embodiments such as the rotary piston assembly 200, are
not hinged. The connector arms 3312 include retainer elements 3380, and the
rotor arms 3312 include retainer elements 3382. When the assembly 3300 is
in its assembled form, the retainer elements 3380, 3382 are intermeshed
relative to the rotary motion of the pistons 3350 and the rotor shaft 3310. In
some embodiments, the retainer elements 3380, 3382 can be formed with
radial geometries that prevent rotation of the rotary pistons 3350 away from
the radius of curvature of the rotary pistons 3350.
[00194] In the exemplary embodiment, contact among the retainer elements
3380, 3382 permits rotary movement to be transmitted between the rotor shaft
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3310 and the rotary pistons 3350. Movement of the pistons 3350 urges motion
of the rotor arms 3312 and the rotor shaft 3310 through contact among the
retainer elements 3380, 3382. Likewise, movement of the rotor shaft 3310 and
the rotor arms 3312 urges motion of the pistons 3350 through contact among
the retainer elements 3380, 3382. In some embodiments, the retainer
elements 3380, 3382 can be connected by one or more fasteners that prevent
rotation of the rotary pistons 3350 away from the radius of curvature of the
rotary pistons 3350. For example, the retainer elements 3380, 3382 can be
connected by bolts, screws, clamps, welds, adhesives, or any other
io appropriate form of connector or fastener.
[00195] In the example rotary piston assembly 3300, contact among the
retainer elements 3380, 3382 permits rotary movement to be transmitted
between the rotor shaft 3310 and the rotary pistons 3350 even if the connector
pin 3314 becomes broken or is missing. In some embodiments, the connector
pin 3314 may be longitudinally constrained by a piston housing (not shown).
For example, the connector pin 3314 may break at some point along its length,
but the housing may be formed such that the ends of the connector pin 3314
may not have sufficient room to permit a broken section of the connector pin
3314 to move far enough longitudinally to become disengaged from the bores
3356. In some embodiments such as this, the retainer elements 3380, 3382
and/or the housing can provide a fail-safe construction that can prevent
broken
pieces of the connector pin 3314 from becoming dislodged from their normal
locations, which can present a risk of if such broken pieces were to become
jammed within components of a rotary actuator in which the rotary piston
assembly 3300 may be used.
[00196] In some embodiments, the connector pin 3314 and the bores 3356
and the bores (not shown) of the rotor arms 3312 can be formed with cross-
sectional geometries that prevent rotation of the connector pin 3314 within
the
bores 3356 and the bores (not shown) of the rotor arms 3312 around the
longitudinal axis of the connector pin 3314. For example, the connector pin
3314 can be a "locking pin" formed with a square, rectangular, triangular,
hex,
star, oval, or any other appropriate non-circular cross-section, and the bores
3356 and the bores (not shown) of the rotor arms 3312 are formed with
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corresponding cross-sections, such that the connector pin 3314 can be
inserted when the bores are aligned and the pistons 3350 are substantially
prevented from rotating about the axis of the connector pin 3314 when the
connector pin 3314 is inserted within the bores.
[00197] In some embodiments, the retainer elements 3380, 3382 and/or the
"locking pin" embodiment of the connector pin 3314 can affect the performance
of the rotary piston assembly 3300. For example, embodiments of the rotary
piston assembly 3300 implementing the retainer elements 3380, 3382 and/or
the "locking pin" embodiment of the connector pin 3314, can reduce or prevent
io relative movement between the pistons 3350 and the rotor arms 3312 as
the
rotary piston assembly 3300 moves within a rotary piston actuator, which can
provide substantially constant torque over a relatively full range of motion
of
the assembly 3300.
[00198] FIGs. 34A and 34B are perspective views of another example rotary
piston 3400. In some embodiments, the rotary piston 3400 can be the rotary
piston 3350 of FIGs. 33A-33C. In some embodiments, features of the rotary
piston 3400 can be used with any of the rotary piston assemblies 200, 700,
1100, 1501, 1701, and 2700, and/or with any of the actuators 400, 800, 1200,
1500, 1750, 1900, 2200, 2300, 2600, 2900, 3000, 3200 and 3300.
[00199] As shown in the example rotary piston of FIGs. 34A-34B, the rotary
piston 3400 includes a piston end 3432 and one or more connector arms 3434.
The piston end 3432 is formed to have a generally elliptical body having a
substantially smooth surface. Each of the connector arms 3434 includes a
bore 3436a and a bore 3436b substantially aligned with the axis of the
elliptical
body of the piston end 3432 and sized to accommodate a connector pin such
as one of the connector pins 3314. Other embodiments may include more
than two bores in a rotary piston. In other embodiments, the piston end 3432
is formed to have a generally rectangular body, or a body having any other
appropriate cross-section.
[00200] In some embodiments, the "multiple pin" embodiment of the rotary
piston 3400 can affect the performance of a rotary piston assembly. For
example, embodiments of rotary piston assemblies implementing the rotary
piston 3400, two locking pins, and a correspondingly formed rotor arm can
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reduce or prevent relative movement between the piston 3400 and the rotor
arms as the rotary piston assembly moves within a rotary piston actuator,
which can provide substantially constant torque over a relatively full range
of
motion of the assembly.
[00201] In some embodiments, one or more of the bores 3436a, 3436b can
be formed with cross-sectional geometries that prevent rotation of a connector
pin, such as the connector pin 3314, within the bores 3436a, 3436b around the
longitudinal axis of the connector pin. For example, one or more of the bores
3436a, 3436b can be formed with square, rectangular, triangular, hex, star,
oval, or any other appropriate non-circular cross-sections, such that
correspondingly configured connector pins can be inserted to substantially
prevent the rotary piston 3400 from rotating about the axes of the bores
3436a,
3436b when the connector pins are inserted within the bores 3436a, 3436b.
[00202] FIG. 35A is a perspective view of another example pressure
chamber assembly 3500. FIG. 35B is a perspective partial cutaway view of
the example pressure chamber assembly 3500. FIG. 35C is a perspective
exploded view of the example pressure chamber assembly 3500. In some
embodiments, features of the pressure chamber assembly 3500 can be used
with any of the rotary piston assemblies 200, 700, 1100, 1501, 1701, and
2700, the rotary piston 3400, and/or with any of the actuators 400, 800, 1200,
1500, 1750, 1900, 2200, 2300, 2600, 2900, 3000, 3200 and 3300. As shown in
FIG. 35C, the pressure chamber assembly 3500 includes a piston housing
3550, a modular housing 3510a, and a modular housing 3510b. The modular
housing 3510a includes an arcuate central recess 3512a, and the modular
housing 3510b includes an arcuate central recess 3512b. In their assembled
form, the arcuate central recesses 3512a and 3512b accommodate the piston
housing 3550.
[00203] As shown in FIG. 35C, the piston housing 3550 is formed to
accommodate a rotary piston 3514 in a cavity 3558. The piston housing 3550
includes a collar 3552. The collar 3552 is formed to hold a seal 3554 in
sealing contact with the rotary piston 3514. In some embodiments, the rotary
piston can be any of the rotary pistons 260, 414, 712, 812, 822,1216, 1520a,
1520b, 1720, 1930, 2222, 2400, 2754, 3350, and 3400. In some
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implementations, the pressure chamber 3550 can be formed as a unitary
piston housing. For example, pressure chamber 3550 may be machined,
extruded, hydro formed, or otherwise formed without forming seams within the
pressure chambers 3550.
[00204] The example rotary piston 3514 includes a bore 3556. In some
embodiments, the bore 3356 can be formed with a cross-sectional geometry
that prevents rotation of a connector pin, such as the connector pin 3314 of
FIGs. 33A-33C, within the bore 3556 and the bores (not shown) of a rotor arm,
such as the rotor arms 3312 around the longitudinal axis of the connector pin.
io For example, the bore 3356 can be formed to accommodate a "locking pin"
formed with a square, rectangular, triangular, hex, star, oval, or any other
appropriate non-circular cross-section, such that the connector pin can be
inserted through the bore 3556 and are substantially prevented from rotating
about the axis of the bore 3556 when the connector pin is inserted within the
bore 3556.
[00205] In some embodiments, the rotary piston 3514 can include retainer
elements. For example, the rotary piston 3514 can include the retainer
elements 3380 (for example, as shown in FIGS 33A-C) that can intermesh with
the retainer elements 3382 to prevent rotation of the rotary piston 3550 away
from the radius of curvature of the rotary pistons 3550.
[00206] FIG. 36 is a perspective view of an example piston housing
assembly 3600. The assembly 3600 includes a piston housing 3650a and a
piston housing 3650b. The piston housings 3650a-3650b each includes a
cavity 3658. In some embodiments, the piston housings 3650a-3650b can be
used in place or in addition to the piston housing 3550 of the example
pressure
chamber assembly 3500 of FIGs. 35A-35C. For example, the piston housings
3650a-3650b can be enclosed by modular housings such as the modular
housings 3510a and 3510b.
[00207] The assembly 3600 includes a collection of fluid ports 3652a and
3652b. The fluid ports 3652a-3652b are in fluid communication with the
cavities 3658 and or fluid supply lines (not shown). In some embodiments, the
fluid ports 3652 can flow fluid among the piston housings 3650a-3650b. For
example, fluid may be applied to pressurize the piston housings 3650a, and
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the fluid will flow through the fluid port 3652a to pressurize the piston
housings
3650b as well. In some embodiments, any appropriate number of piston
housings, such as the piston housings 3650a-3650b, and fluid ports, such as
the fluid ports 3652, can be assembled in an alternating daisy-chain
arrangement to form the assembly 3600.
[00208] Although a few implementations have been described in detail
above, other modifications are possible. For example, the logic flows depicted
in the figures do not require the particular order shown, or sequential order,
to
achieve desirable results. In addition, other steps may be provided, or steps
io may be eliminated, from the described flows, and other components may be
added to, or removed from, the described systems. Accordingly, other
implementations are within the scope of the following claims.
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