Patent Application
20140174287
This invention relates to an actuator device and more particularly to a pressurized rotary vane actuator device wherein the vanes of the rotor are moved by fluid under pressure.
Rotary vane actuators are used as part of some mechanical devices, such as rotary valve assemblies. Such rotary vane actuators typically include multiple subcomponents such as a rotor and two or more stator housing components. These subcomponents generally include a number of seals to prevent leakage of fluid between hydraulic chambers of such rotary valve assemblies.
A common source of leakage in rotary vane actuators can occur across corner seals. Corner seals are used around rotor hubs to overlap the vane seals to prevent cross-vane leakage, but these seals are prone to leaks due to gaps and discontinuities between mating or near-mating surfaces.
U.S. Pat. Nos. 2,984,221; 2,966,144; and 2,951,470 disclose rotary actuators; however, the rotary vane actuator of the present disclosure is distinguishable from and has advantages over prior art rotary vane actuators.
In general, this document describes rotary vane actuators with continuous vane seals disposed on the peripheral edges of the vanes.
In a first aspect, a rotary vane actuator includes a rotor assembly including a rotor hub having a longitudinal axis, said assembly being adapted to connect to an output shaft. The rotor hub has at least a first vane assembly disposed radially on the rotor hub. The first vane assembly includes a first vane of the first vane assembly disposed substantially perpendicular to the longitudinal axis of the rotor hub, and a second vane of the first vane assembly disposed substantially perpendicular to the longitudinal axis of the rotor hub, with an integral valley member between the first vane and second vane. A first continuous seal groove is disposed continuously along a first pathway following a longitudinal peripheral face of the first vane of the first vane assembly, then along a first lateral peripheral face of the first vane, then across a first lateral face of the valley member, then along a first lateral peripheral face of the second vane of the first vane assembly, then along a longitudinal peripheral face of the second vane, then along a second lateral peripheral face of the second vane, then across a second lateral peripheral face of the valley member, and then along a second lateral peripheral face of the second vane to a point of beginning of the first pathway. A first continuous seal is disposed in the first continuous seal groove along the first pathway. At least one other second vane assembly is disposed radially on the rotor hub, and the second vane assembly includes a first vane of the second vane assembly disposed substantially perpendicular to the longitudinal axis of the rotor hub, and a second vane of the second vane assembly disposed substantially perpendicular to the longitudinal axis of the rotor hub, with an integral valley member between the first vane and second vane. A second continuous seal groove disposed continuously along a second pathway follows a longitudinal peripheral face of the first vane of the second vane assembly, then along a first lateral peripheral face of the first vane, then across a first lateral face of the valley member, then along a first lateral peripheral face of the second vane of the second vane assembly, then along a longitudinal peripheral face of the second vane, then along a second lateral peripheral face of the second vane, then across a second lateral peripheral face of the valley member, and then along a second lateral peripheral face of the second vane to a point of beginning of the second pathway. A second continuous seal is disposed in the second continuous seal groove along the second pathway. A stator housing having a central chamber includes an interior surface adapted to receive the rotor assembly, the interior surface is adapted to continuously contact the first continuous seal and the second continuous seal when the rotor assembly is rotated inside of the central chamber. The first vane and second vane assemblies and the stator housing define four pressure chambers inside of the central chamber. A portion of the first pathway of the first seal groove and the first seal that crosses at least one of the lateral peripheral faces of at least one of the valley members is spaced apart from the rotor a predetermined distance to form a fluid flow path for fluid from two pressure chambers positioned substantially opposite each other in the central chamber.
Implementations can include some, all, or none of the following features. The continuous seal can be an elastomer seal or a seal energized by other means such as a spring. The housing can include a split casing comprised of two mating portions each having a mating surface disposed toward the mating portion, each mating portion having a central longitudinal bore for receiving the rotor hub, and a cylindrical recess in the mating surface disposed coaxial with the central bore, said cylindrical recess having a diameter larger than the diameter of the central bore, said cylindrical recess adapted to receive the vanes of the rotor assembly. The housing faces can be mated together, and the two recesses in the mating surfaces can define a pressure chamber. A first external pressure source can provide a rotational fluid at a first pressure for contacting the first vane of the first vane assembly and a second external pressure source can provide a rotational fluid for contacting the second vane of the first vane assembly. Opposing pressure chambers defined by the housing and rotor can have equal surface areas as the rotor rotates within the housing. The output shaft can be configured to connect to a rotary valve stem. The stator housing can be adapted for connection to a valve housing.
In a second aspect, a rotary vane actuator includes a rotor assembly including a rotor hub having a longitudinal axis, said assembly being adapted to connect to an output shaft. The rotor hub includes at least a first vane assembly disposed radially on the rotor hub. The first vane assembly includes a first vane of the first vane assembly disposed substantially perpendicular to the longitudinal axis of the rotor hub and having a first side and a second side, and a second vane of the first vane assembly disposed substantially perpendicular to the longitudinal axis of the rotor hub, with an integral valley member between the first vane and second vane. A first continuous seal groove is disposed continuously along a first pathway following a longitudinal peripheral face of the first vane of the first vane assembly, then along a first lateral peripheral face of the first vane, then across a first lateral face of the valley member, then along a first lateral peripheral face of the second vane of the first vane assembly, then along a longitudinal peripheral face of the second vane, then along a second lateral peripheral face of the second vane, then across a second lateral peripheral face of the valley member, and then along a second lateral peripheral face of the second vane to a point of beginning of the first pathway. A first continuous seal is disposed in the first continuous seal groove along the first pathway. At least a second vane assembly is disposed radially on the rotor hub. The second vane assembly includes a first vane of the second vane assembly disposed substantially perpendicular to the longitudinal axis of the rotor hub and having a first side and a second side, and a second vane of the second vane assembly disposed substantially perpendicular to the longitudinal axis of the rotor hub, with an integral valley member between the first vane and second vane. A second continuous seal groove is disposed continuously along a second pathway following a longitudinal peripheral face of the first vane of the second vane assembly, then along a first lateral peripheral face of the first vane, then across a first lateral face of the valley member, then along a first lateral peripheral face of the second vane of the second vane assembly, then along a longitudinal peripheral face of the second vane, then along a second lateral peripheral face of the second vane, then across a second lateral peripheral face of the valley member, and then along a second lateral peripheral face of the second vane to a point of beginning of the second pathway. A second continuous seal is disposed in the second continuous seal groove along the second pathway. A stator housing having a central chamber includes an interior surface adapted to receive the rotor assembly, said interior surface adapted to continuously contact the first continuous seal and the second continuous seal when the rotor assembly is rotated inside of the central chamber. The central chamber includes a first opposing arcuate ledge and a second opposing arcuate ledge disposed radially inward along the perimeter of the chamber, said first ledge having a first terminal end adapted to contact the first vane of the first vane assembly and the second arcuate ledge adapted to contact the second vane of the first vane assembly.
Various implementations can include some, all, or none of the following features. The continuous seal can be an elastomer seal or a seal energized by other means such as a spring. The vanes of the rotor assembly and the two arcuate ledges can be configured to define four pressure chambers. Opposing pressure chambers defined by the housing and rotor can have substantially equal surface areas as the rotor rotates within the housing. A first opposing pair of the pressure chambers can be adapted to be connected to an external pressure source and a second opposing pair of the pressure chambers can be adapted to be connected to a second external pressure source. The housing can be a split casing that includes two mating portions each having a mating surface disposed toward the mating portion, each mating portion having a central longitudinal bore for receiving the rotor hub, and a cylindrical recess in the mating surface disposed coaxial with the central bore, said cylindrical recess having a diameter larger than the diameter of the central bore, said cylindrical recess adapted to receive the vanes of the rotor assembly. The housing faces can be mated together, and the two recesses in the mating surfaces can define a pressure chamber. A first external pressure source can provide a rotational fluid at a first pressure for contacting the first side of the first vane of the first vane assembly and for contacting the first side of the first vane of the second vane assembly, and the second external pressure source can provide a rotational fluid for contacting the second side of the first vane of the first vane assembly and for contacting the second side of the first vane of the second vane assembly. The first terminal end can also include a first fluid port formed therethrough and the second terminal end can include a second fluid port formed therethrough and the first fluid port can be connected to a rotational fluid provided at a first pressure and the second fluid port can be connected to a rotational fluid provided at a second pressure. The output shaft can be configured to connect to a rotary valve stem. The stator housing can be adapted for connection to a valve housing.
In a third aspect, a method of rotary actuation includes providing a rotor assembly including a rotor hub adapted to connect to an output shaft, said rotor hub having at least two opposing vane assemblies disposed radially on the rotor hub. Each of said vane assemblies includes a first vane disposed substantially perpendicular to a longitudinal axis of the rotor hub and having a first side and a second side, and a second vane disposed substantially perpendicular to a longitudinal axis of the rotor hub, with a valley member between the first vane and second vane. A continuous seal groove is disposed on a peripheral edge of the first and second vanes and the valley member, and a continuous seal is disposed in the continuous seal groove. A stator housing is provided having a central chamber including a first opposing pair of arcuate ledges and a second opposing pair of arcuate ledges disposed radially inward along the perimeter of the chamber, each of said first opposing ledges having a first terminal end and a second terminal end. A rotational fluid is provided at a first pressure and contacting the first side of the first vanes of the opposing vane assemblies with the first rotational fluid. A rotational fluid is provided at a second pressure less than the first pressure and contacting the second side of the first vanes of the opposing vane assemblies with the second rotational fluid. The rotor assembly is rotated in a first direction of rotation. The rotation of the rotor assembly is stopped by contacting at least one of the first terminal ends with at least one of the first vanes.
Various implementations can include some, all, or none of the following features. The second pressure can be increased and the first pressure can be decreased until the second pressure is greater than the first pressure, rotating the rotor assembly in an opposite direction to the first direction of rotation. The rotation of the rotor assembly in the opposite direction can be stopped by contacting at least one of the second terminal ends with at least one of the first vanes of the opposing vane assemblies. The vane assemblies can isolate the rotational fluid into a first opposing pair of chambers and a second opposing pair of chambers, and the method can also include providing the first rotational fluid at the first pressure to the first opposing pair of chambers, and providing the second rotational fluid at the second pressure to the second opposing pair of chambers. Pressure can communicate from the first chamber to the second chamber of the first opposing pair of chambers across a peripheral edge of the rotor hub. The first terminal end can also include a first fluid port formed therethrough and the second terminal end can include a second fluid port formed therethrough, and wherein providing the rotational fluid at a first pressure can be provided through the first fluid port and providing the rotational fluid at a second pressure can be provided through the second fluid port.
The systems and techniques described herein may provide one or more of the following advantages. The rotary vane actuator of the present disclosure has (1) a single continuous vane seal that replaces separate prior art rotor and stator vane seals; (2) in some implementations, eliminates the need for separate corner seals by connecting two opposing pressure chambers across the center of the rotor; (3) eliminates prior art gaps and cross seal leak paths; (4) eliminates check valves and passages in the stator housing necessary to pressure load corner seals used in prior art designs; and (5) in some implementations includes a single continuous unitary seal disposed in a single groove disposed on the peripheral edges of the vanes instead of two or more seals and associated seal support equipment disposed on the peripheral edges of the vanes; (6) pressure can communicate from the first chamber to the second chamber of the first opposing pair of chambers across the peripheral edge of the rotor hub. The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.
This document describes example rotary vane actuators with continuous vane seals. In general, by using continuous vane seals between rotor assemblies and stator housings, the use of corner seals may be eliminated. Corner seals can be associated with undesirable effects, such as reduced mechanical performance, thermal management issues, increased pump size requirements, and reduced reliability.
The housing assembly 12 includes a cylindrical bore 18. As
The rotor 20 is able to rotate about 85 degrees total in a clockwise and counterclockwise direction relative to the stator housing assembly 12. Within the central bore 18, the stator housing 12 includes a first member 32 and a second member 34. The members 32 and 34 act as stops for the rotor 20 and prevent further rotational movement of the rotor 20. A collection of outside lateral surfaces 40 of the members 32 and 34 provide the stops for the rotor 20.
The first and second vanes 57a and 57b include a groove 56. As shown in
As seen in
By creating a fluid pressure differential between the pressure chambers 66 and the pressure chambers 68, the rotor 20 can be urged to rotate clockwise or counterclockwise relative to the stator housing assembly 12. In such designs, however, the corner seals 75 can be a common source of fluid leakage between the pressure chambers 66 and 68. Cross-vane leakage can also negatively impact performance, thermal management, pump sizing, and reliability of the rotary vane actuator 10.
The central chamber 310 includes a central longitudinal bore 315 disposed through a partial inner cylindrical bore section 312a and a partial inner cylindrical bore section 312b that are axially concentric with a partial outer cylindrical bore section 314a and a partial outer cylindrical bore section 314b. The partial cylindrical bore sections 312a, 312b, 314a, and 314b collectively form the surface of the central chamber 310, in which the partial cylindrical bore sections 312a, 312b, 314a, and 314b each form substantially one-quarter of the surface of the central chamber 310. The partial inner cylindrical bore sections 312a and 312b are located substantially opposite each other and in substantially perpendicular opposition to the partial outer cylindrical bore sections 314a and 314b.
The partial inner cylindrical bore sections 312a-312b and the partial outer cylindrical bore sections 314a-314b form arcuate ledges 316a and 316b disposed radially inward along the perimeter of the central chamber 310, substantially perpendicular to the plane of view of
Included in or near the arcuate ledges 316a and 316b is a collection of fluid ports 318a-318b. The fluid ports 318a are in fluidic communication with a fluid port 320a, and the fluid ports 318b are in fluidic communication with a fluid port 320b. In use, a non-compressible fluid (e.g., hydraulic fluid) or compressible fluid (e.g. air, gas) can be flowed to or from the central bore 310 between the fluid ports 318a and the fluid port 320a. Similarly, a fluid can be flowed to or from the central bore 310 between the fluid ports 318b and the fluid port 320b. These fluid flows will be discussed in further detail in the descriptions of
A face 329 of the first housing assembly 301 includes an inner seal groove 330 formed concentrically with an outer seal groove 332. The seal groove 330 accommodates a continuous seal 334 (e.g., an energized seal, an elastomer seal, an o-ring, a d-ring, a square seal), and the seal groove 332 accommodates a continuous seal 336. In some implementations, the continuous seal 334 can be an energized seal, energized by means such as a spring. When the second housing assembly 302 is assembled to the first housing assembly 301, the continuous seals 334-336 form a pair of concentric static seals to resist the passage of pressurized fluid from the central cavity 310 to the ambient environment. In use, the continuous seal 334 contacts a face of the second housing assembly 302 to substantially prevent the passage of pressurized fluid from the central cavity 310. Any fluid that does get past the continuous seal 334 is substantially contained in a space 338 between the seal grooves 330 and 332. A drain hole 340 is formed in the space 338 to divert fluid that leaks past the continuous seal 334 to a drain port (not shown). In some embodiments, the drain port and the drain hole 340 can maintain the space 338 at substantially ambient pressure, and can drain fluid that leaks past the continuous seal 334 before the fluid can become pressurized and possibly leak past the continuous seal 336.
Referring now to
Each of the vane assemblies 402 also includes a continuous seal groove 410. The continuous seal groove 410 is formed on a peripheral edge of the first vane 406, the second vane 408, and the valley member 409. In some implementations, the continuous seal groove 410 can be a single seal groove disposed on the peripheral edge of the first vane 406, the second vane 408, and the valley member 409.
Referring now to
Referring again to
A collection of threaded holes 370 are formed in the rotor hub 404. The threaded holes 370 are axially perpendicular to the rotor hub 404 and, in some implementations, can provide attachment points to which an external mechanism can be attached to and rotated by the rotor hub 404. For example, a shaft for operating the internal moveable closure device of a rotary valve can be bolted to the rotor hub 404 through the threaded holes 370, and the shaft can be rotated by the rotor hub 404 to movably operate the internal movable closure device of a valve. A collection of holes 372 are formed through the housing assemblies 301 and 302. A collection of bolts, such as a bolt 374, can be passed through the holes 372. In some implementations, the bolts 374 can be passed through the holes 372 and threaded into holes in an external mounting surface (not shown). For example, the second housing assembly 302 can be mounted to a rotary valve housing by the bolts 374 to keep the housings 301 and 302 in relative position to a rotary valve housing while the rotor hub 404 rotates the shaft of the internal movable closure device of the rotary valve.
In some implementations, the housing assemblies 301 and 302 can form a split casing, in which the housing assemblies 301 and 302 can act as two mating portions, each having a mating surface disposed toward the mating portion. In some implementations, each mating portion can include the central longitudinal bore 315 for receiving the rotor hub 404, and a cylindrical recess (e.g., the cylindrical bore sections 312a-312b and 314a-314b) in the mating surface disposed coaxial with the central bore 315 in which the cylindrical recess having a diameter larger than the diameter of the central bore 315, and the cylindrical recess can be adapted to receive the vanes 406 and 408 of the rotor assembly 400. In some implementations, when the housing faces are mated together, the two recesses in the mating surfaces can define a pressure chamber.
The seals 522 contact the outer walls of a pair of opposing inner arcuate ledges 514 and contact a pair of opposing outer arcuate ledges 516 to form a pair of opposing first pressure chambers 530 and a pair of opposing second pressure chambers 532. The opposing second pressure chambers 532 are in fluid communication with each other through a fluid passage 534 formed between the seal 522 and a rotor wall 536. The opposing first pressure chambers 530 are in fluid communication with each other through a fluid passage (not shown) formed within the stator housing 504. In some implementations, opposing pressure chambers can be in fluid communication to balance the fluid pressures in opposing pairs of pressure chambers.
The opposing pressure chambers 530 and 532 defined by the stator housing assembly 504 and the rotor assembly 502 have substantially equal surface areas as the rotor assembly 502 rotates within the stator housing assembly 504. In some implementations, such a configuration of equal opposing chambers supplies balanced torque to the rotor assembly 502.
In the configuration illustrated in
Referring now to
Referring now to
U.S. Pat. No. 2,984,221, which was mentioned previously, discloses use of continuous parallel seals on the distal peripheral edges of the vanes (blades) described in that document. However, the seals described in that patent are backed by washers and divider plates, both of which detract from the available travel of that rotor. The seals form a 5th and 6th pressure chamber at each end between continuous seals. Fluid leakage management and/or containment are not apparent or addressed in the prior art patent.
U.S. Pat. No. 2,966,144, also mentioned previously, discloses use of continuous parallel seals on the distal peripheral edge of the vanes described therein. Sealing elements are disposed to form pressure chambers, much the same as the corner seals 75 do in the previous descriptions of
Referring to
Referring to
The stator housing component 700 includes a central chamber 710. The central chamber 710 includes a partial inner cylindrical bore section 712a and a partial inner cylindrical bore section 712b that are axially concentric with a partial outer cylindrical bore section 714a and partial outer cylindrical bore section 714b. The partial cylindrical bore sections 712a, 712b, 714a, and 714b collectively form the surface of the central chamber 710, in which the partial cylindrical bore sections 712a, 712b, 714a, and 714b each form substantially one-quarter of the surface of the central chamber 710. The partial inner cylindrical bore sections 712a and 712b are located substantially opposite each other and in substantially perpendicular opposition to the partial outer cylindrical bore sections 714a and 714b.
The partial inner cylindrical bore sections 712a-712b and the partial outer cylindrical bore sections 714a-714b form arcuate ledges disposed radially inward along the perimeter of the central chamber 710. Each of the arcuate ledges includes a first terminal end 716a adapted to contact a first vane of a rotor assembly (e.g., the rotor assembly 400) and a second terminal end 716b adapted to contact a first vane of a rotor assembly rotated in the opposite direction.
A collection of holes 772 are formed through the stator housing component 700. In some implementations, bolts (e.g., the bolts 374) or other appropriate fasteners can be passed through the holes 772 to couple the stator housing assembly to an external mounting surface (not shown).
Each of the vane assemblies 802 also includes a continuous seal groove 810. The continuous seal groove 810 is formed on a peripheral edge of the first vane 806, the second vane 808, and the valley member 809.
Referring now to
At step 920, a stator housing (e.g., the stator housing 504) is provided. The stator housing has a central chamber including an opposing pair of arcuate ledges (e.g., arcuate ledges 514 and 516) disposed radially inward along the perimeter of the chamber, each of said ledges having a first terminal end (e.g., 316a and hard stop 512) and a second terminal end (e.g., 316b and hard stop 570).
At step 930, a rotational fluid is provided at a first pressure and contacting the first sides of the first vanes with the first rotational fluid. For example, hydraulic fluid can be applied through the fluid port 560 to the fluid ports 562 to contact the first sides of the first vanes.
At step 940, a rotational fluid is provided at a second pressure less than the first pressure and contacting the second sides of the first vanes with the rotational fluid. For example, as the rotor assembly rotates clockwise, fluid in the fluid chambers 530 is displaced and flows through the fluid ports 564 and out through the fluid port 566.
At step 950, the rotor assembly is rotated in a first direction of rotation. For example,
At step 960, the rotation of the rotor assembly is stopped by contacting at least one of the second terminal ends of the first ledges with at least one of the first vanes. For example,
In some implementations, the rotor assembly can be rotated in the opposite direction to the first direction of rotation by increasing the second pressure and reducing the first pressure until the second pressure is greater than the first pressure. For example,
In some implementations, the rotation of the rotor assembly in the opposite direction can be stopped by contacting at least one of the first terminal ends of the first ledges with at least one of the first vanes. For example,
In some implementations, the first terminal end can include a first fluid port formed therethrough and the second terminal end can include a second fluid port formed therethrough. Rotational fluid at a first pressure can be provided through the first fluid port and rotational fluid at a second pressure can be provided through the second fluid port. For example, fluid can be applied at the fluid port 560 and flowed through the fluid ports 562 formed in the hard stops 512. Similarly, fluid can be applied at the fluid port 566 and flowed through the fluid ports 562 formed in the hard stops 570.
In some implementations, the vane assemblies can isolate the rotational fluid into a first opposing pair of chambers and a second opposing pair of chambers, and the process can also include providing the first rotational fluid at the first pressure to the first opposing pair of chambers, and providing the second rotational fluid at the second pressure to the second opposing pair of chambers. For example, fluid applied or removed at the fluid port 560 flows through both fluid ports 562, and will therefore present the same pressure to both of the fluid chambers 532. Similarly, fluid applied or removed at the fluid port 566 flows through both fluid ports 564, and will therefore present the same pressure to both of the fluid chambers 530.
In some implementations, the rotor assembly can be adapted to allow pressure communication from the first chamber to the second chamber of the first opposing pair of chambers across a peripheral edge of the rotor hub. For example, the fluid chambers 532 are in fluid communication with each other across the rotor hub 508, behind the seals 522 through the fluid passages 534.
In some implementations, the rotor assembly can implement a single vane assembly with a single continuous seal. In some implementations, a single-vane rotor assembly may achieve about 170 degrees of total travel in the clockwise and counterclockwise directions of rotation. In some implementations, a two-vane rotor assembly can implement two continuous seals and three different radii of contact. In some implementations, such two-vane rotor assemblies can achieve about 115 degrees of total travel in the clockwise and counterclockwise directions of rotation.
Although a few implementations have been described in detail above, other modifications are possible. Accordingly, other implementations are within the scope of the following claims.
