U.S. patent application number 10/277179 was filed with the patent office on 2003-07-10 for actuator with sealing assembly.
This patent application is currently assigned to Alstom. Invention is credited to Collier, Greg, Klassen, William, Lyons, Andy, Mcllwain, Chris, Prince, Jeff, Schilling, Tyler, Whelan, Pat.
Application Number | 20030126985 10/277179 |
Document ID | / |
Family ID | 26823379 |
Filed Date | 2003-07-10 |
United States Patent
Application |
20030126985 |
Kind Code |
A1 |
Collier, Greg ; et
al. |
July 10, 2003 |
Actuator with sealing assembly
Abstract
Disclosed herein is a rotary vane actuator device with sealing
assembly. The device includes a housing and a sealing assembly. The
housing has a center opening defining a chamber. The housing
includes opposing end plates for surrounding a stator. The stator
having an aligned center opening and a rotor within the chamber.
Within the chamber there are two openings, one serving as an inlet,
the other serving as an outlet for rotational fluid. The rotor
includes a vane assembly fixedly connected thereto. When the fluid
enters the chamber, the fluid contacts the vane and moves the
rotationally in the same direction. Each of the stator and the vane
include seal packs. The end plates include sealing members which
contact the stator and vane seal packs whether in the static or
dynamic condition of the rotor. The combination of the seal packs
and the end plate seal form the sealing assembly.
Inventors: |
Collier, Greg; (Davis,
CA) ; Klassen, William; (Davis, CA) ; Lyons,
Andy; (Davis, CA) ; Mcllwain, Chris;
(Sacramento, CA) ; Prince, Jeff; (Kennewick,
WA) ; Schilling, Tyler; (Davis, CA) ; Whelan,
Pat; (Vacaville, CA) |
Correspondence
Address: |
PENINSULA IP GROUP
A Professional Law Corporation
Suite 101
2290 North First Street
San Jose
CA
95131
US
|
Assignee: |
Alstom
|
Family ID: |
26823379 |
Appl. No.: |
10/277179 |
Filed: |
October 19, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10277179 |
Oct 19, 2002 |
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09520562 |
Mar 8, 2000 |
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6520068 |
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60125215 |
Mar 18, 1999 |
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Current U.S.
Class: |
92/120 |
Current CPC
Class: |
F01C 9/002 20130101;
F01C 21/0881 20130101; B25J 9/148 20130101; F15B 15/12 20130101;
F05C 2225/00 20130101 |
Class at
Publication: |
92/120 |
International
Class: |
F01C 009/00 |
Claims
What is claimed is:
1. A rotary actuator device, comprising: a housing including: the
housing having at least one opening for allowing fluid into and out
of the housing; first and second end plates; a stator housing
between the end plates, the stator housing having a central opening
and when assembled with the end plates defining a chamber, a stator
fixedly located on the stator housing and being within the central
opening; and a rotor within the central opening and journaled by
the housing for rotational movement relative to the stator, the
rotor including a vane assembly for facilitating movement of rotor
upon flow of fluid into and out of the chamber; and a sealing
assembly including: a stator seal pack removably connected to the
stator, a rotor seal pack removably connected to the rotor vane
assembly; and each end plates having an end plate seal inside the
central opening of the stator housing and between the end plates
and the rotor, whereby, upon assembly of the actuator device, at
least a portion of the end plate seal is within the chamber.
2. A sealing assembly for a high pressure, fluid rotary actuator
device including a rotor, a stator housing having a central opening
and a stator fixedly positioned thereto and end plates, the end
plates journaling rotor in the central opening for rotational
movement relative to the stator and the end plates enclosing the
central opening to define a chamber, the sealing assembly
comprising: the rotor having a rotor seal pack preventing fluid
by-pass to the ports or the environment; the stator having a stator
seal pack preventing fluid by-pass to the the ports or the
environment; and the end plates each having a seal, at least a
portion of the seal extending into the chamber and being retained
at the housing from failing into the chamber, the end caps seals
pack preventing fluid by-pass to the the ports or the environment,
whereby, a three dimensional seal is provided throughout the
chamber for preventing fluid leakage from the chamber.
3. For use in a rotary actuator including a rotor within a chamber
defined by a housing formed by end plates and a stator housing, a
sealing assembly comprising: at least two vane seal packs including
a sealing member and a suspension system; and an end seal on each
end of the rotor, the end seal being at least partially within the
housing and mating each vane seal to form a fluid tight seal both
statically and through rotation of the rotor.
Description
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
[0001] This invention relates to an actuator device and more
particularly to a high pressure rotary vane actuator device wherein
the vanes of the rotor are moved by fluid under high pressure.
[0002] Rotary vane actuators are used as an essential part of some
robotic devices. When connected with a series of servo-motors and
drives and using the proper electro-mechanical principles and
devices, such vane actuators are essential to the entire robotic
device. For example, some robotic arms, such Alstom Automation
Schilling Robotics' Orion manipulator have as many as seven joints.
Such robotic arms employ a ported rotary vane actuator having a
like number of ports. Each joint is connected to one or more ports
and a valve for moving each joint separately and/or conjunctively
depending on the user's desires.
[0003] An important use of such robotic arms is for submersible
exploration. For example, exploring to find oil or other minerals
and deposits requires exploration of undersea areas. A robotic arm
is attached to either a manned or unmanned submersible. The sea
bottom can then be explored as if a man were walking on the ocean
bottom instead of being safely on a ship or in the submersible. The
robotic arm must be able to work in difficult and even treacherous
environments whose is ecology is highly sensitive to pollution,
especially hydro carbons found in oil leaks.
[0004] In order for these robotic arms to function properly, the
rotor is rotated by fluid under extremely high pressure. The
rotating fluid is typically under pressures of 3000 pounds per
square inch (PSI) ambient as is known for such devices. The adverse
environmental conditions also create working difficulties. For
example pressures at up to 13,000 PSI gage on the ocean floor are
experienced during operation of the robotic arms.
[0005] As noted above, the robotic arm typically works in
environments having sensitive ecology, which are subject to close
political scrutiny. It is consequently unacceptable for the
rotating fluid to leak into such environments. Great care must be
taken to ensure that there is no fluid leakage even under the
extreme conditions presented by environments such as the North Sea,
for example. Also, the pressure within the actuator must likewise
not give rise to any leakage.
[0006] Additionally, any leakage of fluid in the actuator will
cause the robotic device to be moved freely without operator
activation. When there is a drop in fluid pressure due to such
leakage there will be play in the affected joint. This means that
the arm joint can move by the forces of its surroundings. Given the
gravitational forces acting upon the robotic device, the affected
robotic arm can move freely, destroying the ability of the robotic
device to remain stationary when electrical and/or hydraulic power
is turned off. A submersible is, by design, tightly packed with
sensitive and crucial instruments and devices. If a robotic device
were to move when turned off, these sensitive and crucial
instruments and devices may be damaged. This too is an unacceptable
condition and one which requires the actuator to be as nearly leak
proof as possible.
[0007] Various devices have been aimed at resolving the leakage
issue in rotary vane actuator devices with limited success. For
example, in U.S. Pat. No. 4,510,850, attempts are made to place a
seal between the end walls of the vane and the actuator housing. In
this embodiment the vane seals are linear and attempt to match seal
length with the seal between the vane seal and actuator
housing.
[0008] In U.S. Pat. No. 4,495,856, a body sleeve houses a stator
and a rotary vane. The rotary vane extends radially from the drive
shaft is seals are placed at either end of the drive shaft where it
is secured by a pair of head assemblies. The body sleeve includes
metal end plates at either end of the head assemblies which are
designed to retain tapered, roller thrust bearings within the head
assemblies. By tapering, the potential leak path becomes narrower
and then can be filled with sealing materials. However, the
machining and consequently manufacturing costs may be quite high
and even prohibitive for providing this type of arrangement.
[0009] In U.S. Pat. No. 4,565,119, there is disclosed a vane-type
rotary actuator employing a disc like seal member made of an
elastic material with a center opening. The vanes here appear to
use one or more elastomeric O-rings to make continuous contact with
the with a cylinder. However, this disclosure does appear not
address the potential leak path between either the ports or the end
plates.
[0010] In order to perfect a seal in any of the above devices or
any known device, special attention to manufacturing detail may
cause the actuator to become so expensive and difficult to
manufacture as to be useless. Tolerances required between flat
surface seals and a matching of lengths of flat surface seals are
difficult if not impossible to accomplish consistently using
traditional economically acceptable and known manufacturing
techniques.
[0011] What is needed is an actuator which lends itself to known
manufacturing techniques and provides the actuator with virtually
no leak paths. Such an actuator must neither leak internally (port
to port) nor externally, chamber to environment. The desired
actuator would cost no more to manufacture than known actuators and
would add to the effective and efficient operation of the device of
which it was a part.
SUMMARY OF THE INVENTION
[0012] It is an object of this invention to provide a rotary vane
actuator device that provides three dimensional sealing whether the
actuator is static or dynamic.
[0013] It is an additional object of this invention to provide such
an actuator device that minimizes the potential leak paths using
system sealing assemblies positioned within the chamber of rotation
and at least partially external thereto.
[0014] It is an additional object of this invention to provide such
an actuator device which is manufactured using traditional methods
and equipment.
[0015] In accordance with the above objects and those that will be
mentioned and will become apparent below, the rotary vane actuator
device in accordance with this invention comprises:
[0016] a housing including:
[0017] the housing having at least one opening for allowing fluid
into and out of the housing;
[0018] first and second end plates;
[0019] a stator housing between the end plates, the stator housing
having a central opening and when assembled with the end plates
defining a chamber, a stator fixedly located on the stator housing
and being within the central opening; and
[0020] a rotor within the central opening and journaled by the
housing for rotational movement relative to the stator, the rotor
including a vane assembly for facilitating movement of rotor upon
flow of fluid into and out of the chamber; and
[0021] a sealing assembly including:
[0022] a stator seal pack removably connected to the stator, a
rotor seal pack removably connected to the rotor vane assembly;
and
[0023] each end plate having an end plate seal inside the central
opening of the stator housing and between the end plates and the
rotor,
[0024] whereby, upon assembly of the actuator device, at least a
portion of the end plate seal is within the chamber.
[0025] With the actuator described above, a three dimensional
sealing system is provided which seals potential leak paths from
port to port, from port to the environment and from the chamber to
the environment. Each of these potential leak paths is blocked by
at least one of the seals described above.
[0026] In a preferred embodiment of the actuator in accordance with
the invention, each of the seal packs includes a vane seal and each
of the vane seals and the end plate seal are made from a plastic
material. Preferably, the vane seals are made from polyurethane and
the end plate seal is made from a high strength plastic such as
Delrin.RTM. and Kynar.RTM..
[0027] In another preferred embodiment, the end plate seals are at
least partially within the chamber and fixed from falling into the
chamber. Preferably the end plate seal has an open center and is
force fit over the rotor and on either side where the end plates
fit with the rotor squeezing the end plate seal therebetween.
[0028] It is an advantage of this invention to provide a system of
compatible plastic seals which when in contact with one another
provides a fluid proof seal.
[0029] It is an additional advantage of this invention to provide
an actuator, which features end plate seals that are at least
partially within the chamber.
BRIEF DESCRIPTION OF THE DRAWING
[0030] For a further understanding of the objects and advantages of
the present invention, reference should be had to the following
detailed description, taken in conjunction with the accompanying
drawing, in which like parts are given like reference numerals and
wherein:
[0031] FIG. 1 is a perspective plan view of one embodiment of the
rotary actuator device in accordance with the invention.
[0032] FIG. 2 is a sectional plan view of the embodiment of the
actuator device in accordance with the invention shown in FIG. 1
illustrating the rotor in the chamber.
[0033] FIG. 3 is another sectional plan view of the embodiment of
the rotary actuator device in accordance with the invention shown
in FIG. 1 illustrating the stator in relationship to the rotor
within the chamber.
[0034] FIG. 4 is an enlarged perspective view of the end plate seal
illustrating the seal being at least partially inside the
chamber.
[0035] FIG. 5 is an enlarged perspective view of the assembled
stator seal pack.
[0036] FIG. 6 is an enlarged perspective plan view illustrating the
seal and rotor pack assemblies in exploded view.
[0037] FIG. 7 is a partial sectional view of the end plate seal in
perspective.
[0038] FIG. 8 illustrates an alternative end plate seal at least
partially within the chamber.
[0039] FIG. 9 illustrates an alternative seal pack assembly
compatible with the end plate seal of FIG. 8.
DETAILED DESCRIPTION OF THE INVENTION
[0040] The invention will now be described with reference to FIG.
1, which illustrates a preferred embodiment of the invention, a
rotary actuator device, shown generally by the numeral 10. The
rotary actuator device 10 includes a housing assembly, generally
indicated by the numeral 12 (FIG. 2) and a sealing assembly
generally indicated by the numeral 14. The details of each assembly
12 and 14 are set forth below.
[0041] The housing assembly 14 includes a stator housing 16 having
a central opening 18. The housing assembly 14 includes a rotor 20
within the central opening 18 and the rotor 20 journaled within the
housing assembly 14 for rotation within the central opening 18. The
housing assembly 14 includes end plates 22 having a central opening
24. The central opening 24 being aligned with the central opening
18. The openings 18 and 24 define a chamber 26.
[0042] As shown in FIGS. 1 and 3, the stator assembly 14 includes a
stator 30 in the central opening 18. The stator 30 includes a first
member 32 and a second member 34 and a groove 36 in-between the
members 32 and 34. Each of the members 32 and 34 act as stops for
the rotor 20 and prevents further rotational movement of the rotor
20 as will become more apparent with respect to the detailed
description of the rotor 20 operation below. The inside lateral
surfaces 38 of each of the members 32 and 34 are opposed and define
the groove 36.
[0043] The outside lateral surfaces 40 of the members 32 and 34
provide the stops for the rotor 20. The outside lateral surfaces 40
serve as abutment members for the rotor vane as will be more fully
appreciated below.
[0044] The rotor 20 includes a vane assembly 50 secured to the
outside surface as clearly shown in FIGS. 1, 2 and 3. The vane
assembly 50 includes first and second vanes 52 and 54 and a groove
56 defined therebetween. In the preferred embodiment shown in
accordance with the drawing, the rotor 20 includes a machined outer
surface 58 (FIG. 1) for facilitating each of the vanes 52 and 54
being secured to the rotor 20. Each of the vanes 52 and 54 also
includes a similar machine surface 60 for mating with the rotor
machined surface 58.
[0045] The opposed inside surfaces 62 of the vanes 52 and 54 define
the groove 56. The outer surfaces 64 of the vane 50 serve as stops.
The surfaces 64 abut against compatible surfaces 40 of the stator
30, alternatively during full rotation. As can be seen in FIG. 3,
the abutment surfaces 40 and 64 prevent 360.degree. through
rotation and instead provide approximately 270.degree. of
rotation.
[0046] As seen in FIG. 2, the rotor 20 is journaled for rotation
within the housing assembly 12. The rotor 20 rotates within the
chamber 26 (FIG. 3) depending upon the ingress and egress of fluid
into and out of the chamber. As show in FIG. 3, the housing
assembly includes a first and a second opening 70 and 72 for
allowing fluid into and out of the chamber 26. It will be
appreciated that as fluid flows through opening 70 and is drawn out
of opening 72, an inlet is thereby defined by opening 70 and an
outlet by opening 72. Such movement of the fluid causing pressures
against the vane assembly 50 and the vane assembly causes the rotor
20 to move in the same direction. To reverse direction of the rotor
20, the roles of openings 70 and 72 are reversed such that the
opening 70 becomes the outlet and opening 72 becomes the inlet.
[0047] As is well known, rotary vane actuators of the type
disclosed herein may include a plurality of ports on the rotor.
Each of these ports is controlled by an electro-mechanical
mechanism by the operator known as servomotors. The servo motors
control a series of leaves located on the rotor and designated as
numeral 80 which seal the ports upon activation and de-activation
of the servo motors by the operators.
[0048] The vane assembly 50 is secured to the rotor 20 by a
plurality of bolts which are threaded through the vanes 52 and 54
and into the rotor 20 which has a compatible threaded openings.
Each of the vanes 52 and 54 are secured in this manner to the
rotor. It will be appreciated that other methods of securing the
vane assembly 50 to the rotor 20 are possible and within the scope
of the instant invention.
[0049] As shown in FIGS. 1-3, the end plates 22 are secured to the
stator housing 16 through bolts and nuts. With the addition of
seals, as described below, the stator housing 16 and the end plates
22 are sealed to one another. The stator housing 16 has a machined
face on either side and the end plates 22 have a compatible
machined face to facilitate the seal.
[0050] In addition to the usual O-ring seals, the sealing assembly
14 includes three additional assemblies to promote
three-dimensional sealing of the chamber 26. With respect to FIG.
1, there is shown a plurality of O-ring seals designated generally
90 as is conventional with rotary vane actuator devices.
Additionally, the stator 30 and the rotor 20 include seal packs
generally designated by the numeral 100.
[0051] As shown in FIG. 6, each of the seal packs 100 fits in and
is connected to their respective groove, 36 and 56. Each seal pack
100 includes a vane seal 102. The vane seal 102 is donut shaped and
made from polyurethane. It will be appreciated that other
configurations and materials are all within the scope of the
invention. For example other materials include thermoplastics and
thermoset plastics.
[0052] The outer surface 104 of the vane seal 102 has a notch on
either end and in profile appears as arcuate surface 106. As will
appreciated more fully below this accommodates each of the end
plate seals 122 (FIG. 7). Also by providing two notches one need
not be concerned with matching a particular end plate seal to a
particular seal pack. Consequently, manufacturing is relatively
simple and each seal pack can be made the same. In this way only
one vane seal 102 need to be made to facilitate both rotor and
stator seal packs 100.
[0053] The donut opening (illustrated clearly in FIG. 2) of the
vane seal 102 includes a suspension system 110 for the seal pack
100. The suspension system 110 illustrated in FIGS. 5 and 6 include
a stabilizer mechanism 112 and a shock absorber 114. In the
preferred embodiment, the stabilizer mechanism 112 comprises
aluminum filler plate 116 and the shock absorber 114 comprises an
O-ring 118 wrapped tightly around the outer surface of the aluminum
filler plate 116.
[0054] The seal packs 100 include backing plates 120 on either side
of the seal 102 which add rigidity to the backing plates 120 and
the seal 102 as well as the suspension system 110. The backing
plates 120 are allowed to move small amounts but are constrained
from large movement by the inside of the chamber including the
stator groove 36, rotor groove 56, the stator housing 16, the end
plates 22, the rotor 20, and the end plate seals 122. The backing
plates are made from an engineering plastic or other materials,
which function similarly.
[0055] Each of the aluminum filler plate 116 and the backing plates
120 include a notch similarly shaped and compatibly positioned so
that it matches the notch 106 with a similar arcuate surface as
best shown in FIGS. 5 and 6. This allows the suspension system to
maintain the seal in the chamber 26 during rotation.
[0056] The end plates 22 include an end plate seal 122 between the
end plates 22 and the rotor 20. As clearly shown in FIG. 4, the end
plate seal 122 is fit between the rotor 20 and the end plates 22
and at least of portion of the end plate seal 122 is within the
chamber 26. And, at least a portion of the end plate seal 122 is
out of the chamber 26 and secured to the end plate 22. The end
plate seals 122 are fit over the rotor 20. The end plate seals 122
rotates with the rotor 20 or remains stationary during rotation of
the rotor 20. Alternatively, the end seal plates 122 may be fixed
to the end plates 22 through an opening in the end plate seals 122.
In any case, the end plate seals 122 is fit to either the rotor 20
or the end plates 22 so that even under high pressure and rotation
it does not fall into the chamber 26. This is similarly true under
static conditions as well.
[0057] As best shown in FIG. 7, the end plate seal 122 has a lipped
surface 124. The lipped surface 124 is compatibly arcuate with the
arcuate surfaces of the notch 106. This allows the notch 106 of the
rotor seal pack 100 to ride along the lipped surface 124 during
rotation of the rotor 20. The suspension system 110 flexes and
maintains the contact with the end plate seals 122 during rotation
of the rotor 20 despite various imperfections of the contacting
surfaces of the seal packs 100 and the end plate seals 122.
[0058] Similarly the stator seal pack notch 106 engages the lipped
surface of the end plate seals 122. It will be appreciated that
both ends of the stator seal pack and the rotor seal pack 100 has
notches at either end to accommodate each end plate seal 122.
[0059] By maintaining contact the chamber seal is maintained and no
fluid can leak either between the ports or out to the environment.
In other words, the possible leak paths are blocked three
dimensionally. More particularly, each of leak paths between the
end plate seals 122 and the seal pack 100 and the rotor 20 and
between the end plate seals 122 and the seal pack 100 and the end
plate 22 are three dimensionally blocked.
[0060] As illustrated in FIGS. 8 and 9, there is shown an
alternative sealing assembly including alternative end plate seals
150 and an alternative seal pack 160. In this embodiment, the outer
surface 152 of the end plate seals 150 is flat and not arcuate.
Similarly, the vane seal 162 of seal pack 160 has a compatible
outer surface 164, which is flat. The two outer surfaces 152 and
164 must be at virtually the same length to prevent leakage.
Contact throughout the adjoining lengths of the outer surfaces 152
and 164 must be maintained to prevent the development of leak paths
the chamber 26.
[0061] Clearly, making the lengths exactly the same or virtually
exactly the same is difficult and costly. Even small amounts of
leakage into the environment from the chamber are unacceptable in
sensitive environmental areas. Thus, while the embodiment shown in
FIGS. 8 and 9 is functional and within the scope and spirit of the
invention, it is not necessarily the preferred embodiment.
[0062] The arcuate lengths of the lipped surfaces 124 on the end
plate seal and the compatible arcuate surfaces of the notches 106
and allows a certain amount of tolerance not present in flat
structures. In combination with the suspension system 110, the
arcuate surfaces allow the dynamic seal to hold throughout movement
of the rotor 20. Even with irregularities in the arcuate surfaces
and slight length variations, the arcuate surfaces maintain contact
and cause the seal to be maintained three dimensionally. By
maintaining contact a complete seal is assured.
[0063] Additionally, the arcuate length is also a preferred version
because they are longer and therefore a greater amount of surface
area contacts. This provides the three dimensional seal with a
greater amount of surface area and therefore a greater tolerance in
movement while still maintaining the seal contact.
[0064] The end seal is made from a compatible plastic material,
such as Delrin.RTM. or Kynar.RTM. which when in contact with each
of the vane seals 102 to form a fluid proof seal. Thus, whether
static or dynamic, the seals, when in contact maintain a fluid
proof seal with all sealing surfaces being plastic. Each potential
leak path is thus blocked appropriately by a fluid proof seal for
three dimensional sealing because the vane seal is continuously in
contact with the end plate seal as the rotor 20 rotates through the
chamber 26.
[0065] As described above, a fluid proof seal blocks all possible
three leak paths through the rotary vane actuator device 10. The
three possible leak paths are from port to the port, from the port
to the environment and from the chamber 26 to the environment. Each
of these potential paths is blocked by at least one of the seals
described above.
[0066] In operation, the device 10 is installed and assembled as
part of a robotic arm or other such device. The seal packs 100 are
assembled in their respective grooves 36 and 56 and affixed
thereto. The end plate seals 122 are set in place between the
stator housing 16, the rotor 20 and each end plate plates 22 with
at least a portion of the end plate seals being within the chamber
26. The remaining portion of the end plate seal being outside the
chamber 26 and being trapped by the mating of the end plate seals
22, the rotor 20 and the stator housing 16.
[0067] As noted above, the housing assembly 12 has at least two
openings 70 and 72 as clearly shown in FIG. 3. Each of the openings
70 and 72 may serve alternatively as an inlet or outlet depending
upon the direction of rotation desired. For example if it is
desired to rotate the rotor 20 from opening 70 towards opening 72,
the fluid under pressure (approximately 3000 PSI) is sent through
opening 70 and retracted from opening 72. The flow of the fluid
against the first vane 52 forces the second vane 54 to rotate
towards the second opening 72.
[0068] As noted above, the stator and rotor seal packs 100 maintain
continuous sealing contact with the end plate seals 122 thereby
creating a constant three-dimensional seal even during rotation.
The suspension system 110 holds the contact despite the
irregularities in surface areas or movement of the rotor.
[0069] The rotational movement continues until the second vane 54
rotates against the abutment surface defined by the outside of the
stator 30. This gives the rotor 20 approximately 270.degree.. It
will be appreciated that similar rotation is possible in the
reverse direction by alternating the inlet and outlet. Thus to
reverse the rotational direction of the rotor 20, the inlet is
defined by opening 72 and the outlet by opening 70.
[0070] While the foregoing detailed description has described
several embodiments of the rotary vane actuator in accordance with
this invention, it is to be understood that the above description
is illustrative only and not limiting of the disclosed invention.
Particularly, the rotary vane actuator need not include any
particular arcuate shaped mating sealing surface, but rather the
arcuate shaped mating surfaces of each sealing member provide the
tolerance and flexibility preferred for manufacturing using
traditional methods for same. Additionally, the while plastic
sealing elements need not be used exclusively, they are preferred
because of the flexibility and durability of the sealing elements
in the design provided herein. While plastic sealing elements may
be used in other designs their effectiveness is in question. This
design represents an advance so that such plastic materials may be
used. Thus, the invention is to be limited only by the claims as
set forth below.
* * * * *