Abstract:
The subject matter of this specification can be embodied in, among other things, a rotary vane actuator that includes a rotor assembly including a rotor hub. The rotor hub has a first and second vane assembly disposed radially on the rotor hub. Continuous seals are disposed in continuous seal grooves along pathways provided along the vanes. 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 vane assemblies and the stator housing define pressure chambers inside of the central chamber.

Description:
TECHNICAL FIELD 
       [0001]    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. 
       BACKGROUND 
       [0002]    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. 
         [0003]    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. 
         [0004]    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. 
       SUMMARY 
       [0005]    In general, this document describes rotary vane actuators with continuous vane seals disposed on the peripheral edges of the vanes. 
         [0006]    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. 
         [0007]    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. 
         [0008]    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. 
         [0009]    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. 
         [0010]    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. 
         [0011]    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. 
         [0012]    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. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0013]      FIGS. 1 and 2  are cross-sectional views of an example of a prior art rotary vane actuator. 
           [0014]      FIGS. 3 ,  3 A,  3 B, and  4  are cross-sectional views of components of a first implementation of an example rotary vane actuator with continuous vane seals. 
           [0015]      FIGS. 5A-5D  and  6 A- 6 D are cross-sectional views of the first example rotary vane actuator with continuous vane seals in various operational positions. 
           [0016]      FIG. 7  is a perspective view of a stator housing component of the first example rotary vane actuator. 
           [0017]      FIGS. 8A-8E  are perspective views of the first example rotor assembly. 
           [0018]      FIG. 9  is a flow diagram of an example process for rotating a rotary vane actuator with continuous vane seals. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    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. 
         [0020]      FIGS. 1 and 2  are cross-sectional views of an example of a prior art rotary vane actuator  10 . The rotary actuator device  10  includes a stator housing assembly  12  and a sealing assembly generally indicated by the numeral  14 . The details of each assembly  12  and  14  are set forth below. 
         [0021]    The housing assembly  12  includes a cylindrical bore  18 . As  FIG. 1  shows, the cylindrical bore  18  is a chamber that encloses a cylindrical rotor  20 . As  FIG. 1  also shows, the rotor  20  is a machined cylindrical component consisting of a first rotor vane  57   a , a second rotor vane  57   b  and a centered cylindrical hub  59 . In some implementations, the diameter and linear dimensions of the first and second rotor vanes  57   a ,  57   b  are equivalent to the diameter and depth of the cylindrical bore  18 . 
         [0022]    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 . 
         [0023]    The first and second vanes  57   a  and  57   b  include a groove  56 . As shown in  FIG. 2 , each of the grooves  56  includes one or more sealing assemblies configured to contact the wall of the cylindrical bore  18  The sealing assemblies include a cap seal, an elastomer seal  58 , and a spacer. The first and second members  32  and  34  include a groove  60 . Each of the grooves  60  includes one or more sealing assemblies  14  configured to contact the cylindrical rotor  20 . The sealing assemblies  14  include a cap seal, an elastomer seal  62 , and a spacer. The stator housing assembly  12  also includes a groove  74  that is formed to accommodate a corner seal  75 . 
         [0024]    As seen in  FIG. 1 , the sealing assemblies (e.g., sealing assembly  14 ), and the corner seal  75 , define a pair of pressure chambers  66  positioned radially opposite of each other across the rotor  20 , and a pair of opposing pressure chambers  68  positioned radially opposite each other across the rotor  20 . In use, fluid is introduced or removed from the pressure chambers  66  through a fluid port  70 , and fluid is oppositely flowed from the pressure chambers  68  through a fluid port  72 . 
         [0025]    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 . 
         [0026]      FIGS. 3 ,  3 A,  3 B, and  4  are cross-sectional views of components of an example rotary vane actuator  300  with continuous vane seals. When assembled, the rotary vane actuator includes a stator housing and a rotor assembly. In use, the rotor assembly is coupled to a mechanical device, such as a valve mechanism, and fluid is controllably applied or removed from the rotary vane actuator to cause the rotor assembly to rotate, and in turn cause the coupled mechanical device to rotate. In some implementations, the rotor assembly may also be coupled to a rotational position sensor to detect the position of the rotor assembly as it is controllably rotated. 
         [0027]      FIGS. 3 and 4  are cross-sectional views of an example stator housing of a rotary vane actuator  300 . The rotary vane actuator  300  includes a first housing assembly  301  and a second housing assembly  302 . In an exemplary implementation, as shown in  FIG. 4 , the housing assemblies  301 - 302  are coupled to each other by a collection of bolts  303  that pass through corresponding holes  304  in the second housing assembly  302 , and are threaded into threaded holes  305  formed within the first housing assembly  301 . The first and second housing assemblies  301 - 302 , when appropriately coupled together, form a central chamber  310 . 
         [0028]    The central chamber  310  includes a central longitudinal bore  315  disposed through a partial inner cylindrical bore section  312   a  and a partial inner cylindrical bore section  312   b  that are axially concentric with a partial outer cylindrical bore section  314   a  and a partial outer cylindrical bore section  314   b . The partial cylindrical bore sections  312   a ,  312   b ,  314   a , and  314   b  collectively form the surface of the central chamber  310 , in which the partial cylindrical bore sections  312   a ,  312   b ,  314   a , and  314   b  each form substantially one-quarter of the surface of the central chamber  310 . The partial inner cylindrical bore sections  312   a  and  312   b  are located substantially opposite each other and in substantially perpendicular opposition to the partial outer cylindrical bore sections  314   a  and  314   b.    
         [0029]    The partial inner cylindrical bore sections  312   a - 312   b  and the partial outer cylindrical bore sections  314   a - 314   b  form arcuate ledges  316   a  and  316   b  disposed radially inward along the perimeter of the central chamber  310 , substantially perpendicular to the plane of view of  FIG. 3 . Each of the arcuate ledges includes a first terminal end  316   a  adapted to contact a first vane of a rotor assembly and a second terminal end  316   b  adapted to contact a second vane of a rotor assembly. The rotor assembly will be discussed further in the descriptions of  FIGS. 3A ,  3 B, and  8 A- 8 E. 
         [0030]    Included in or near the arcuate ledges  316   a  and  316   b  is a collection of fluid ports  318   a - 318   b . The fluid ports  318   a  are in fluidic communication with a fluid port  320   a , and the fluid ports  318   b  are in fluidic communication with a fluid port  320   b . 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  318   a  and the fluid port  320   a . Similarly, a fluid can be flowed to or from the central bore  310  between the fluid ports  318   b  and the fluid port  320   b . These fluid flows will be discussed in further detail in the descriptions of  FIGS. 5A-5D  and  6 A- 6 D. 
         [0031]    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 . 
         [0032]    Referring now to  FIG. 3A , an end view of an example rotor assembly  400  is shown. The rotor assembly  400  includes two opposing vane assemblies  402  disposed radially on a rotor hub  404 . Each of the vane assemblies  402  includes a first vane  406  disposed substantially perpendicular to a longitudinal axis of the rotor hub  404 , and a second vane  408  disposed substantially perpendicular to the longitudinal axis of the rotor hub  404 . A valley member  409  is formed between the first vane  406  and the second vane  408 . 
         [0033]    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 . 
         [0034]    Referring now to  FIG. 3B , the rotor assembly  400  is shown with a continuous seal  450  disposed in the continuous seal groove  410 . In some implementations, the seal  450  can be an energized seal, an elastomer seal, an o-ring, a d-ring, a square seal, or any other appropriate form of seal. In some implementations, the seal  450  can be an energized seal, energized by means such as a spring. The first vane  406  extends from the rotor hub  404  a distance, that when the rotor assembly  400  is disposed in chamber  310 , is sufficient to bring a section of the continuous seal  450 , disposed along a surface  452  of the first vane  406 , into sealing contact with the outer cylindrical bore sections  314   a - 314   b  (see  FIG. 3 ). Similarly, second vane  408  extends from the rotor hub  404  a distance that is sufficient to bring a section of the continuous seal  450 , disposed along a surface  454  of the second vane  408 , into sealing contact with the inner cylindrical bore sections  312   a - 312   b . As will be discussed further in reference to  FIGS. 5A-5D  and  6 A- 6 D, when the rotor assembly  400  is appropriately assembled with the stator housing assembly  301 - 302 , four fluidic chambers are formed within the rotary vane actuator  300 . 
         [0035]    Referring again to  FIG. 4 , the housing assemblies  301  and  302  also include a collection of seal grooves  460  and seals  462 . In some implementations, the seals  462  can be an energized seal, an elastomer seal, an o-ring, a d-ring, a square seal, or any other appropriate form of seal. In some implementations, the seal  450  can be an energized seal, energized by means such as a spring. In some implementations, the seals  462  can be dynamic seals that resist the leakage of fluid from the central chamber  310  to the ambient environment along the axis of the rotor hub  404 . 
         [0036]    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. 
         [0037]    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  312   a - 312   b  and  314   a - 314   b ) 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. 
         [0038]      FIGS. 5A-5D  and  6 A- 6 D are cross-sectional views of an example rotary vane actuator  500  with continuous vane seals in various operational positions. In some implementations, the rotary vane actuator  500  can be an assemblage of the first housing assembly  301 , second housing assembly  302  and the rotor assembly  400  of  FIGS. 3 ,  3 A,  3 B, and  4 . 
         [0039]      FIGS. 5A-5D  depict the clockwise rotational operation of the actuator  500 . Referring to  FIG. 5A , the actuator  500  is shown with a rotor assembly  502  in a fully-counterclockwise position relative to a stator housing  504 . A pair of opposing vane assemblies  505  is disposed radially on a rotor hub  508 . A seal  522  is disposed in a seal groove  520  that is formed along the edges of each vane assembly  505 . The seal groove  520  extends along the edges of a long vane  506 , a valley member  507 , and a short vane  510 . In some implementations, the seal groove  520  can be a single seal groove disposed on the peripheral edge of the vane assembly  505  and the valley member  507 . In some implementations, the seal  522  can be a single elastic member. 
         [0040]    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. 
         [0041]    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 . 
         [0042]    In the configuration illustrated in  FIG. 5A , the rotor assembly  502  is in a fully counterclockwise position, in which the long vanes  506  are in contact with hard stops  512  formed at the junctions of the inner and outer arcuate ledges  514  and  516 . A pressurized fluid (e.g., hydraulic fluid) can be applied to a fluid port  560  that is in fluid communication with a pair of fluid ports  562 . Similarly, the pressurized fluid can be applied to a fluid port  566  that is in fluid communication with a pair of fluid ports  564 . In some implementations the opposing pressure chambers can be adapted to be connected to an external pressure source through the fluid ports  560  and the fluid ports  562 , and the opposing pressure chambers  532  can be adapted to be connected to a second external pressure source through the fluid ports  566  and the fluid ports  564 . In some implementations, the first external pressure source can provide a rotational fluid (e.g., hydraulic fluid) at a first pressure for contacting the long vanes  506  and the second external pressure source can provide a rotational fluid for contacting the short vane  510 . In some implementations, the first rotational fluid can contact the long vane  506  of the opposing chamber and the second rotational fluid can contact the short vane  510  of the opposing chamber. 
         [0043]    Referring now to  FIG. 5B , as the fluid is applied through the fluid ports  562  the rotor assembly  502  is urged clockwise relative to the stator housing  504 . As the rotor assembly  502  rotates, the long vanes  506  sweep along the outer arcuate ledges  516  and the short vanes  510  sweep along the inner arcuate ledges  514 . The fluid applied through the fluid ports  562  intermingles with the fluid in the second chambers  532  and gradually fills the spaces originally occupied by the first pressure chambers  530 . Fluid in the first pressure chambers  530 , displaced by the rotation of the rotor assembly  502 , flows out a pair of fluid ports  564  in fluid communication with a fluid port  566 . 
         [0044]    Referring now to  FIG. 5C , as the fluid further fills the second pressure chambers  532 , the rotor assembly  502  continues to rotate clockwise. Eventually, as depicted in  FIG. 5D , the rotor assembly  502  can reach a terminal clockwise position relative to the stator housing  504 . Clockwise rotation of the rotor assembly  502  stops when the long vanes  506  contact hard stops  570  formed at the junctions of the inner and outer arcuate ledges  514  and  516 . 
         [0045]    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 5 th  and 6 th  pressure chamber at each end between continuous seals. Fluid leakage management and/or containment are not apparent or addressed in the prior art patent. 
         [0046]    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  FIGS. 1 and 2 , with the same disadvantages. The embodiments described in the present disclosure do not include parallel seals running down the distal peripheral edge of vanes  406  and  408 . The disclosure of the U.S. Pat. No. 2,966,144 describes gates similar to the arcuate ledges  316   a - 316   b  projecting from the stator wall, the arcuate ledges  316   a - 316   b  are configured and function differently from the gates described by the U.S. Pat. No. 2,966,144. Fluid leakage management and/or containment are not addressed in the prior art patent. 
         [0047]      FIGS. 6A-6D  depict the counter-clockwise rotational operation of the actuator  500 . Referring to  FIG. 6A , the actuator  500  is shown in substantially the same configuration as was discussed in the description of  FIG. 5D . The rotor assembly  502  is depicted as being in a terminal clockwise position relative to the stator housing  504 . The long vanes  506  are in contact with the hard stops  570 . Counter-clockwise rotation of the rotor assembly  502  can be accomplished by applying pressurized fluid to the fluid ports  564  through the fluid port  566 . 
         [0048]    Referring to  FIG. 6B , the fluid has partly filled the first pressure chambers  530 . As the first pressure chambers  530  are filled, the rotor assembly  502  is urged counter-clockwise relative to the stator housing  504 . Fluid in the second pressure chambers  532  displaced by the rotation of the rotor assembly  502  flows out the fluid ports  562  to the fluid port  560 . 
         [0049]    Referring to  FIG. 6C , the fluid continues to fill the first pressure chambers  530  and rotate the rotor assembly  502  counter-clockwise. Referring now to  FIG. 6D , the rotor assembly  502  is shown fully rotated in the counter-clockwise direction. The counter-clockwise rotation is stopped when the long vanes  506  contact the hard stops  512 . 
         [0050]      FIG. 7  is a perspective view of a stator housing component  700 . In some implementations, the stator housing component  700  can be the second housing assembly  302  of  FIGS. 3 and 4 . The stator housing component  700  includes a collection of holes  704 . In some implementations, bolts or other appropriate fasteners can be passed through the holes  704  to couple the stator housing component  700  to other components. For example, the stator housing component  700  may be coupled to the first housing assembly  301  of  FIGS. 3 and 4  by passing the bolts  303  through the holes  704  and into the threaded holes  305  within the first housing assembly  301 . 
         [0051]    The stator housing component  700  includes a central chamber  710 . The central chamber  710  includes a partial inner cylindrical bore section  712   a  and a partial inner cylindrical bore section  712   b  that are axially concentric with a partial outer cylindrical bore section  714   a  and partial outer cylindrical bore section  714   b . The partial cylindrical bore sections  712   a ,  712   b ,  714   a , and  714   b  collectively form the surface of the central chamber  710 , in which the partial cylindrical bore sections  712   a ,  712   b ,  714   a , and  714   b  each form substantially one-quarter of the surface of the central chamber  710 . The partial inner cylindrical bore sections  712   a  and  712   b  are located substantially opposite each other and in substantially perpendicular opposition to the partial outer cylindrical bore sections  714   a  and  714   b.    
         [0052]    The partial inner cylindrical bore sections  712   a - 712   b  and the partial outer cylindrical bore sections  714   a - 714   b  form arcuate ledges disposed radially inward along the perimeter of the central chamber  710 . Each of the arcuate ledges includes a first terminal end  716   a  adapted to contact a first vane of a rotor assembly (e.g., the rotor assembly  400 ) and a second terminal end  716   b  adapted to contact a first vane of a rotor assembly rotated in the opposite direction. 
         [0053]    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). 
         [0054]      FIGS. 8A-8E  are perspective views of an example rotor assembly  800 . In some implementations, the rotor assembly  800  can be the rotor assembly  400  of  FIGS. 3A and 3B , or the rotor assembly  502  of  FIGS. 5A-5D  and  6 A- 6 D. The rotor assembly  800  includes two opposing vane assemblies  802  disposed radially on a rotor hub  804 . Each of the vane assemblies  802  includes a first vane  806  disposed substantially perpendicular to a longitudinal axis of the rotor hub  804 , and a second vane  808  disposed substantially perpendicular to the longitudinal axis of the rotor hub  804 . A valley member  809  is formed between the first vane  806  and the second vane  808 . 
         [0055]    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 . 
         [0056]    Referring now to  FIGS. 8D and 8E , the rotor assembly  800  is shown with a continuous seal  850  disposed in the continuous seal groove  810 . In some implementations, the seal  850  can be an energized seal, an elastomer seal, an o-ring, a d-ring, a square seal, or any other appropriate form of seal. In some implementations, the seal  450  can be an energized seal, energized by means such as a spring. When the rotor assembly  800  is properly assembled with a stator housing assembly, such as the first housing assembly  301  and second housing assembly  302  or the stator housing assembly  504 , the vane assemblies  802  extend from the rotor hub  804  a distance that is sufficient to bring the continuous seal  850  into sealing contact with the walls of the central bore sections of the stator housing assembly. 
         [0057]      FIG. 9  is a flow diagram of an example process  900  for rotating a rotary vane actuator with continuous vane seals (e.g., the rotary vane actuator  500  of  FIGS. 5A-5D  and  6 A- 6 D). At step  910 , a rotor assembly (e.g., the rotor assembly  502 ) is provided. The rotor assembly includes a rotor hub (e.g., rotor hub  508 ) adapted to connect to an output shaft, and has at least two opposing vane assemblies (e.g., vane assemblies  505 ) disposed radially on the rotor hub. Each of the vane assemblies includes a first vane disposed substantially perpendicular to a longitudinal axis of the rotor (e.g., the long vane  506 ) and having a first side and a second side, and a second vane disposed substantially perpendicular to a longitudinal axis of the rotor (e.g., the short vane  510 ), with a valley member between the first vane and second vane (e.g., the valley member  507 ), and a continuous seal groove disposed on a peripheral edge of the first and second vanes and the valley member (e.g., seal groove  410  and  810 ), a continuous seal disposed in the continuous seal groove (e.g., the seal  450  and  850 ). 
         [0058]    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.,  316   a  and hard stop  512 ) and a second terminal end (e.g.,  316   b  and hard stop  570 ). 
         [0059]    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. 
         [0060]    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 . 
         [0061]    At step  950 , the rotor assembly is rotated in a first direction of rotation. For example,  FIGS. 5A-5C  illustrate the rotor assembly  502  being rotated in a clockwise direction. 
         [0062]    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,  FIG. 5D  illustrates the rotor assembly  502  with the long vanes  506  in contact with hard stops  512 . 
         [0063]    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,  FIGS. 6A-6C  illustrate the rotor assembly  502  being rotated in a counter-clockwise direction. 
         [0064]    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,  FIG. 6D  shows the rotor assembly  502  at a counter-clockwise rotational hard stop. 
         [0065]    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 . 
         [0066]    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 . 
         [0067]    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 . 
         [0068]    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. 
         [0069]    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.