rotary actuator

Abstract

An exemplary rotary actuator includes: a tube; an end cap coupled to an end of the tube, wherein the end cap has a main sensor cavity; a shaft disposed in the tube, wherein the shaft is rotatable within the tube when fluid flow is provided within the tube; a sensing target ring rotatably coupled to the shaft, wherein the sensing target ring has a sensor surface and an annular groove, and a rotary pressure seal disposed in the annular groove; and a main sensor mounted in the main sensor cavity of the end cap, wherein the main sensor interacts with the sensor surface of the sensing target ring to provide sensor information indicating the rotational position of the sensing target ring and the shaft, and wherein the rotary pressure seal isolates the main sensor from the high-pressure fluid in the tube.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 602,874, filed November 27, 2023, the entire contents of which are incorporated herein by reference as if fully set forth in this specification. Background Technology

[0002] Some rotary actuators involve using high-pressure fluid to induce rotation of the output shaft. Such rotary actuators are exposed to high torque, thrust, and radial loads because they are designed to be part of the structural load path in most applications. In particular, existing rotary actuator constructions resolve axial forces generated by internal hydraulic pressure solely through end caps or shafts. Therefore, it may be desirable to construct rotary actuators in a manner that reduces stress on their components.

[0003] In some applications, it may be desirable to measure the rotational position of the output shaft of a rotary actuator. However, standard encoders and position sensors are not designed to withstand the loads that rotary actuators can handle, and therefore such sensors cannot be placed in high-load conditions without additional support structures and space to operate.

[0004] Therefore, it might be desirable to integrate the sensor within the pressure chamber of the rotary actuator to remove the sensor from external loads. However, exposing the sensor to high pressure levels (e.g., 5000 pounds per square inch) presents an additional obstacle to the use of some sensors. Therefore, it might be desirable to have a position sensor configured to accurately measure the rotational position of the rotary actuator's output shaft, regardless of the operating pressure within the actuator, external conditions, or the internal load under which the rotary actuator operates.

[0005] These and other considerations are presented in this article. Summary of the Invention

[0006] This disclosure describes an implementation involving a rotary actuator.

[0007] In a first example embodiment, this disclosure describes a rotary actuator comprising: a tube; an end cap coupled to an end of the tube, wherein the end cap has a main sensor cavity; a shaft disposed within the tube, wherein the shaft is rotatable within the tube when fluid flow is provided within the tube; a sensing target ring rotatably coupled to the shaft, wherein the sensing target ring has a sensor surface and an annular groove, a rotary pressure seal disposed in the annular groove; and a main sensor mounted in the main sensor cavity of the end cap, wherein the main sensor interacts with the sensor surface of the sensing target ring to provide sensor information indicating the rotational position of the sensing target ring and the shaft, and wherein the rotary pressure seal isolates the main sensor from the high-pressure fluid in the tube.

[0008] In a second exemplary embodiment, this disclosure also describes a method of operating the rotary actuator of the first exemplary embodiment.

[0009] The foregoing description of the invention is merely illustrative and is not intended to be limiting in any way. Other aspects, embodiments, and features will become apparent from the accompanying drawings and the following detailed description, in addition to the illustrative aspects, embodiments, and features described above. Attached Figure Description

[0010] The appended claims set forth novel features that are considered illustrative examples. However, the illustrative examples, preferred modes of use, further purposes, and description thereof will be best understood by referring to the following detailed description of the illustrative examples of this disclosure when read in conjunction with the accompanying drawings.

[0011] Figure 1 A perspective view of a rotary actuator according to an example embodiment is shown.

[0012] Figure 2 An example implementation is shown. Figure 1 A perspective view of the end cap of the rotary actuator.

[0013] Figure 3 An example implementation is shown. Figure 2 Transparent front view of the end cap.

[0014] Figure 4 An example implementation is shown. Figure 2-3 A perspective bottom view of the end cap.

[0015] Figure 5 An example implementation is shown. Figure 1 A perspective cross-sectional side view of a rotary actuator.

[0016] Figure 6A An example implementation is shown. Figure 5An enlarged partial cross-sectional side view of the rotary actuator.

[0017] Figure 6B An enlarged partial cross-sectional side view of a rotary actuator 100 with a dedicated cap according to an example embodiment is shown.

[0018] Figure 7 An example implementation is shown. Figure 6A A perspective view of the ring of the rotary actuator.

[0019] Figure 8A An example implementation is shown. Figure 1 A top view of the cross-section of a rotary actuator, in which the piston sleeve extends.

[0020] Figure 8B An example implementation is shown. Figure 1 A top view of the cross-section of a rotary actuator, with the piston sleeve retracted.

[0021] Figure 9 An example implementation is shown. Figure 1 A perspective bottom view of a rotary actuator.

[0022] Figure 10A A perspective view of a sensor according to an example embodiment is shown.

[0023] Figure 10B An example implementation is shown. Figure 10A A top view of the sensor.

[0024] Figure 10C Cross-sectional views of the sensor shown in Figures 10A-10B according to an exemplary embodiment are illustrated.

[0025] Figure 11 This is a flowchart of a method for operating a rotary actuator according to an example implementation. Detailed Implementation

[0026] In this example, a rotary actuator is disclosed that enhances the load-bearing capacity of the rotary actuator. The rotary actuator is also configured to be serviceable without complete disassembly and without damaging the pressure chamber of the rotary actuator.

[0027] In the example, the disclosed rotary actuator also provides a combination of an integrated rotary position sensor fully contained within the rotary actuator's coverage area. The rotary actuator may include a double-precision sensing target ring for the sensor, wherein the target ring is incorporated within the rotary actuator and timed independently for the rotation of the rotary actuator.

[0028] Furthermore, in the disclosed actuator configuration, the internal axial force generated by hydraulic pressure is distributed between the shaft and the end cap. This results in a reduced stress level for each component compared to conventional rotary actuators.

[0029] Figure 1 A perspective view of a rotary actuator 100 according to an example embodiment is shown. The rotary actuator 100 includes a tube 102 that operates as a housing for components of the rotary actuator 100. In one example, the tube 102 may be made of a high-grade weldable steel material (e.g., A514 DOM or 4130 steel) and has a honed inner diameter (ID) surface and machined attachment features / structures (e.g., holes) at each end.

[0030] In the example, tube 102 can be mounted to a housing 104 supporting tube 102. For example, housing 104 can be made of sheet metal. Housing 104 is secured to a first end cap 106 and a second end cap 108 (e.g., via screws) and is sealed along the periphery of its adjacent end caps 106, 108 and tube 102. (The following text is related to...) Figure 9 The enclosure 104 may enclose the electronic circuitry for the sensor, wherein the output of such a sensor is provided via a connector 109 (e.g., a 12-pin connector) located at the center of one side of the enclosure 104.

[0031] The tube 102 is held between a first end cap 106 and a second end cap 108. End caps 106 and 108 may also be referred to as “legs” of the rotary actuator 100. End caps 106 and 108 include machined features that allow the rotary actuator 100 to be securely mounted to a rigid grounded structure and allow the end caps 106 and 108 to be coupled to the tube 102. End caps 106 and 108 may be made of, for example, high-grade steel (such as 4140 steel).

[0032] In the example embodiment shown in the figures, end caps 106 and 108 are configured as pillow blocks, which facilitate mounting the rotary actuator 100 to a flat surface of a frame or fixture. Tube 102, together with end caps 106 and 108, forms a pressure vessel or enclosure for the rotary actuator 100. End caps 106 and 108 also function as axial stops for pistons, as described below.

[0033] The rotary actuator 100 includes a first compression seal / dedicated seal 110 at one end of the rotary actuator 100, and also includes a second compression seal / dedicated seal 112 at the other end of the rotary actuator 100. The compression seals / dedicated seals 110, 112 may be, for example, elastomeric seals, and function as primary seals to prevent debris (e.g., dust) and moisture from being drawn into the rotary actuator 100.

[0034] According to the example implementation, Figure 2 A perspective view of the first end cap 106 is shown. Figure 3 A transparent front view of the first end cap 106 is shown, and Figure 4 A perspective bottom view of the first end cap 106 is shown. The first end cap 106 has an end cap body 200, and the end cap body 200 has a mounting base 202 integrated therewith.

[0035] For example, the mounting base 202 has a first foot 204 and a second foot 206 for mounting the first end cap 106 to a flat surface. For example, as Figure 3 As shown, the first leg 204 has a mounting hole 205, and the second leg 206 has a mounting hole 207. Fasteners (e.g., screws or bolts) can be installed through the mounting holes 205, 207 to couple the first end cap 106 to, for example, a frame or other base component.

[0036] The end cap body 200 has a circular cavity 208 in which the sensing target ring and the sealing carrier are mounted, as described below. Furthermore, the first end cap 106 has a plurality of holes, such as holes 210, formed in a circular array around its outward-facing side. The tube 102 of the rotary actuator 100 may have a corresponding set of holes, allowing fasteners to be installed through the holes (e.g., holes 210) of the first end cap 106 and the corresponding holes of the tube 102 to couple the first end cap 106 to the tube 102.

[0037] The end cap body 200 of the first end cap 106 defines or includes one or more ports, such as a first port 212 and a second port 214. A fluid source (e.g., a pump) can be fluidly coupled to ports 212, 214 to provide fluid flow thereto. The fluid can then flow through a transverse channel, for example... Figure 3 The transverse channels 216 and 218 are shown.

[0038] refer to Figure 4 The transverse channels 216, 216 then connect the fluid to the axial or longitudinal channel 219 and the longitudinal channel 220, respectively. The longitudinal channels 219, 220 can then deliver the fluid to the chamber within the tube 102 of the rotary actuator 100 to move the piston, as described below. Figures 8A-8B As stated above.

[0039] like Figure 3-4As shown, the first end cap 106 also includes a main sensor cavity 222. In this example, the first end cap 106 may also include a reference sensor cavity 224. The sensor cavities 222 and 224 may be configured, for example, as countersunk recesses, and corresponding sensors may be mounted in the main sensor cavity 222 and the reference sensor cavity 224 to detect the position of the rotation axis, as described in more detail below. The end cap 106 also includes a slot 223 extending from the main sensor cavity 222 and a slot 225 extending from the reference sensor cavity 224. The slots 223 and 225 operate as wire channels or conduits through which wires are routed from the sensor to a connector 109 in the central section of the housing 104. The second end cap 108 may be configured similarly to the first end cap 106.

[0040] Figure 5 A perspective cross-sectional side view of a rotary actuator 100 according to an example embodiment is shown. Figure 5 The rotary actuator 100 depicted in the example embodiment is a helical rotary actuator.

[0041] The rotary actuator 100 includes a shaft 300 disposed along the longitudinal axis of the rotary actuator 100. The shaft 300 of the rotary actuator 100 is coaxial with the tube 102 and is configured to rotate about the longitudinal axis of the rotary actuator 100.

[0042] In one example, shaft 300 may be made of high-grade steel, such as 4140 steel or Austempered Ductile Iron (ADI). Shaft 300 has a straight spline portion 301 (e.g., an AGMA-classified straight spline) that allows shaft 300 to be rotatably coupled to output hub 318. As shown, a first compression seal 110 is mounted in a recess formed between output hub 318 and first end cap 106.

[0043] Specifically, the output hub 318 may include a machined straight spline (e.g., an AGMA straight spline) that mates with the straight spline portion 301 of the shaft 300 for transmitting torque to the output hub 318. Thus, as the shaft 300 rotates, the output hub 318 rotates with it. Other torque transmission mechanisms, such as key-keyway devices or self-retaining tapered devices, may be used. In this way, the shaft 300 is configured to transmit torque and maintain the alignment of the output hub 318 (a similar output hub at the other end of the rotary actuator 100). In this example, the output hub 318 may be made of high-grade steel (such as 4140 steel) or ADI.

[0044] At each end of the shaft 300, the shaft 300 includes a first threaded portion 303 and a second threaded portion 305 machined into the shaft 300. In one example, the threaded portions 303 and 305 may have opposite directions of rotation. For example, the first threaded portion 303 may be a standard UN series right-hand (RH) primary thread, and the second threaded portion 305 may be a standard UN series left-hand (LH) secondary thread.

[0045] The helix of a thread can be configured to twist in two possible directions, and this configuration is referred to as the thread's "helix orientation." A thread oriented such that a threaded article (e.g., the first threaded portion 303), when viewed from an axis passing through the center of the helix, moves away from the observer when rotating clockwise and towards the observer when rotating counterclockwise, is called an RH thread because this configuration follows the right-hand grip rule. A thread oriented in the opposite direction (e.g., the second threaded portion 305) is called an LH thread. Shaft 300 also includes an external helical spline portion 307 machined within shaft 300. For example, the external helical spline portion 307 may be a helical spline classified according to standard AGMA.

[0046] The rotary actuator 100 has an annular gear 302 that projects radially inward from a tube 102 into a cavity 304 within the tube 102. The annular gear 302 may, for example, be welded to the inner surface of the tube 102. In one example, the annular gear 302 may be made of a high-grade weldable steel (such as A514 DOM or 4130 steel). The annular gear 302 includes an internal helical spline 309 (e.g., an AGMA helical spline) machined onto the inner diameter of the annular gear and projecting radially inward within the cavity 304.

[0047] The rotary actuator 100 also includes a piston sleeve 306 (hollow annular piston) mounted in a cavity 304 around a shaft 300. In other words, the piston sleeve 306 surrounds the shaft 300 and is radially positioned between the shaft 300 and the inner surfaces of the annular gear 302 and the tube 102. The piston sleeve 306 has a piston head 308 and a piston rod 310. The piston head 308 may have external and internal recesses, in which radial seals are provided to seal fluid between the two sides of the piston head 308. In one example, the piston sleeve 306 may be made of ductile iron.

[0048] The piston sleeve 306 has an outer helical spline 312 that projects radially outward from the piston rod 310 and is configured to engage with the inner helical spline 309 of the ring gear 302. The piston sleeve 306 also has an inner helical spline 314 that projects radially inward into the longitudinal cavity of the piston sleeve 306 to engage with the outer helical spline portion 307 of the shaft 300.

[0049] For example, the external helical spline 312 and the internal helical spline 314 of the shaft 300 can be AGMA helical splines. They have opposite helical spline directions. For example, the internal helical spline 314 can be a clockwise helical spline machined on the inner diameter of the piston rod 310, and the external helical spline 312 can be a counterclockwise helical spline machined on the outer diameter of the piston rod 310. The piston sleeve 306 is configured to convert its linear motion under hydraulic pressure into rotational motion of the shaft 300 via opposite helical splines, as described below. Figures 8A to 8B As stated above.

[0050] Figure 6A An enlarged partial cross-sectional side view of a rotary actuator 100 according to an example embodiment is shown. The output hub 318 may have a plurality of holes, such as holes 320, arranged in a circular array around an end face of the output hub 318. Fasteners may be installed in these holes to couple the output hub 318 to a rotatable component of the device.

[0051] The output hub 318 is held within the rotary actuator 100 via a retaining ring 322 and a locking ring 324. The retaining ring 322 and the locking ring 324 are threaded onto the shaft 300.

[0052] Specifically, the retaining ring 322 may have an RH thread (e.g., a UN series right-hand thread on its inner diameter) to facilitate threaded engagement with the first threaded portion 303 of the shaft 300. As shown, the retaining ring 322 interfaces with the output hub 318 to retain the output hub 318. In one example, the retaining ring 322 may be made of high-grade steel (such as 4140 steel).

[0053] On the other hand, the locking ring 324 may have an LH thread (e.g., a UN series left-hand thread on its inner diameter) to facilitate threaded engagement with the second threaded portion 305 of the shaft 300. As shown, the locking ring 324 abuts against the retaining ring 322. In this example, the locking ring 324 may be made of high-grade steel (such as 4140 or 4340 steel).

[0054] The retaining ring 322 and locking ring 324 hold the output hub 318 to the shaft 300 and prevent accidental loosening or disassembly of the rotary actuator 100. Specifically, as described above, the thread of the retaining ring 322 may have a helix direction opposite to that of the corresponding thread of the locking ring 324. Specifically, in the exemplary embodiment described above, the thread of the retaining ring 322 is an RH thread, while the thread of the locking ring 324 is an LH thread. With this configuration, the locking ring 324 can be further tightened as the shaft 300 rotates, preventing the retaining ring 322 and the output hub 318 from being unscrewed from the shaft 300.

[0055] Figure 6BAn enlarged partial cross-sectional side view of a rotary actuator 100 with a dedicated cap 321 according to an example embodiment is shown. In one example embodiment, the rotary actuator 100 may include a dedicated cap 321 at the end of a shaft 300 to completely enclose the shaft 300, retaining ring 322, and locking ring 324 from the external environment of the rotary actuator 100.

[0056] The special cap 321 may have threads defining a center hole 323 and aligned with a corresponding hole in the shaft 300. A flush-mounted fastener (not shown) may be screwed into the center hole 323 and the corresponding hole in the shaft 300 to couple the special cap 321 to the shaft 300. A radial seal 325 may be mounted in a groove formed in the output hub 318 surrounding the outer surface of the special cap 321. With this configuration, the shaft 300 is completely enclosed, protected, and sealed by the protective sleeve defined by the special cap 321.

[0057] Return to reference Figure 6A The rotary actuator 100 includes a radial seal 326 (e.g., an elastomeric seal) mounted in an annular groove formed in the output hub 318. The radial seal 326 operates as an auxiliary compression seal to the first compression seal 110 (the main compression seal) described above.

[0058] The rotary actuator 100 also includes a face seal 328 mounted in an annular groove formed on the end face of the output hub 318. The face seal 328 is also a compression seal and may be particularly advantageous in a device in which the rotary actuator 100 is mounted vertically, where, for example, water may accumulate on the end face of the output hub 318.

[0059] The rotary actuator 100 also includes a wear ring 330 radially mounted between the output hub 318 and the first end cap 106. The wear ring 330 operates as a radial bearing or wear guide to facilitate rotation of the output hub 318 relative to the first end cap 106. As an example, the wear ring 330 may be made of a durable bronze alloy or a low-friction composite material.

[0060] As described above, the output hub 318 is configured as a rotatable component, which is coupled to the output hub 318 via fasteners in the bore 320. When the output hub 318 rotates, causing the rotatable component to rotate with it, the output hub 318 is subjected to a load. The load borne by the output hub 318 is transmitted to the wear ring 330 and then to the first end cap 106, which is configured to be mounted to a fixed frame (ground). Thus, the wear ring 330 transmits radial force from the output hub 318 to the first end cap 106 in the load path from the fixed frame or the ground.

[0061] This configuration of the rotary actuator 100 (where the axial distance between the fastener in the bore 320 and the first end cap 106 is short) enhances the torque-carrying capacity of the rotary actuator 100. In particular, the length of the torque arm between the fastener and the first end cap 106 is short, resulting in a smaller torque. This significantly reduces the torque experienced by the shaft 300.

[0062] The rotary actuator 100 also includes a thrust bearing 332 axially mounted between the output hub 318 and the first end cap 106. The thrust bearing 332 may be a thrust washer or a thrust roller bearing and is configured to transmit thrust from the output hub 318 to the first end cap 106 in the load path from the device to the ground. In this way, the thrust bearing 332 can increase the thrust (axial) carrying capacity of the rotary actuator 100.

[0063] The thrust bearing 332 can be made of any number of materials or constructions. For example, it can be made of low-friction composite homogeneous materials or steel roller thrust bearing types.

[0064] Advantageously, this configuration facilitates the maintenance of the rotary actuator. In particular, the output hub 318 can be removed to provide access to the thrust bearing 332, wear ring 330, retaining ring 322, locking ring 324, first compression seal 110, and radial seal 326. The output hub 318, thrust bearing 332, wear ring 330, retaining ring 322, locking ring 324, first compression seal 110, and radial seal 326 can then be repaired or replaced without interrupting the chamber 304 (the pressure chamber of the rotary actuator 100), without introducing air, and without having to vent air from the rotary actuator 100.

[0065] The rotary actuator 100 also includes a sensing target ring 334. The sensing target ring 334 is at least partially mounted to the shaft 300 within the first end cap 106 (in the circular cavity 208). Specifically, the sensing target ring 334 is radially sandwiched between the shaft 300 and the first end cap 106 and is rotatably coupled to the shaft 300. The sensing target ring 334 operates as a target ring for a sensor mounted to the first end cap 106 and also as a seal carrier.

[0066] Figure 7 A perspective view of a sensing target ring 334 according to an example embodiment is shown. In the example, the sensing target ring 334 may be made of steel or aluminum.

[0067] The sensing target ring 334 may have an internal spline 400 (e.g., a machined AGMA straight spline) that is machined into the inner diameter of the sensing target ring and configured to engage a corresponding spline or tooth in the shaft 300 such that the sensing target ring 334 rotates with the shaft 300 as the shaft 300 rotates.

[0068] The sensing target ring 334 may have timing marks, such as notches 402, on its end face. These timing marks facilitate mounting the sensing target ring 334 to the shaft 300 at specific (repeatable or "timed") rotational positions. The sensing target ring 334 has a sensor surface 404 (e.g., an inclined surface or a cam surface) with a precisely machined specific profile that provides a radial surface position that varies continuously from the longitudinal axis of the shaft 300 (i.e., from the center of the sensing target ring 334) during rotational movement of the shaft 300 and the sensing target ring 334. A main sensor mounted to the first end cap 106 interacts with the sensor surface 404 to sense the rotational position of the shaft 300 and the sensing target ring 334, as described below.

[0069] In the example, the rotary actuator 100 includes components mounted on the above-mentioned... Figure 3-4 The reference sensor is described in the reference sensor cavity 224, with a first end cap 106 serving as the reference sensor. In these examples, the sensing target ring 334 includes a cylindrical portion 406 concentric with the shaft 300. The cylindrical portion 406 has a circular surface 407, which functions as a reference surface that can make the measurements of the main sensor more accurate.

[0070] The circular surface 407 of the cylindrical portion 406 has a constant radius (i.e., points on the circular surface 407 are equidistant from the axis 300 and the center of the sensing target ring 334). A reference sensor can interact with the cylindrical portion 406 to provide corresponding sensor information indicating the position of the circular surface 407 of the cylindrical portion 406, which is concentric with the axis 300. The circular surface 407 of the cylindrical portion 406 provides a baseline surface for measurement via the reference sensor.

[0071] like Figure 7 As shown, the sensing target ring 334 also includes a first annular groove 408 adjacent to the cylindrical portion 406 and a second annular groove 410 axially spaced from the first annular groove 408. Referring together to Figures 6-7, the rotary actuator 100 includes a first rotary pressure seal 338 disposed in the first annular groove 408 and a second rotary pressure seal 340 disposed in the second annular groove 410.

[0072] Rotary pressure seals 338 and 340 seal the pressure chamber within tube 102 relative to the external environment of the rotary actuator 100. Therefore, the rotary pressure seals 338 and 340 create a seal around the sensing target ring 334 as the sensing target ring 334 rotates. Furthermore, the rotary pressure seals 338 and 340 isolate the sensor and reference sensor, mounted in the first end cap 106, relative to the high-pressure fluid in the cavity 304 within tube 102.

[0073] Rotary pressure seals 338 and 340 further distribute axial hydraulic pressure between the first end cap 106 and the shaft 300. Specifically, a portion of the axial hydraulic / fluid force is applied to the first end cap 106, while a portion is applied to the shaft 300. This reduces stress on the first end cap 106 and the shaft 300.

[0074] like Figure 5 As shown, the other side of the rotary actuator 100 (with) Figure 6A (The side shown is opposite) can be similar to Figure 6A The side shown is constructed. Therefore, on this opposite side, the rotary actuator 100 similarly includes a corresponding output hub, a corresponding retaining ring and locking ring, a corresponding wear-resistant ring and thrust bearing, and a corresponding sensor target ring, as shown. Figure 5 As shown.

[0075] Figure 8A A cross-sectional top view of a rotary actuator 100 according to an exemplary embodiment is shown, wherein a piston sleeve 306 extends. A second end cap 108 may include one or more ports, such as port 500 and port 502 (similar to ports 212, 214 of the first end cap 106). Fluid can be received from a fluid source (e.g., a pump) through one or both of ports 500 and 502. Fluid received at port 500 flows through a transverse channel 504 and a longitudinal channel 506 into a head chamber 508 within a cavity 304 in the tube 102. Similarly, fluid received at port 502 flows through a transverse channel 510 and a longitudinal channel 512 into the head chamber 508.

[0076] Therefore, when fluid is supplied to one or both of ports 500 and 502, the fluid flows into head chamber 508 and in the distal axial direction (e.g., in...). Figure 8A (From center to right) A fluid force is applied to the piston head 308 of the piston sleeve 306. The fluid force causes the piston sleeve 306 to move axially or longitudinally in the distal axial direction until it reaches... Figure 8A The extended position shown is where it is stopped by the first end cap 106.

[0077] Due to the engagement of the outer helical spline 312 of the piston sleeve 306 with the inner helical spline 309 of the ring gear 302 (which is fixed), the piston sleeve 306 rotates as it translates linearly in the distal direction. Furthermore, due to the engagement of the inner helical spline 314 of the piston sleeve 306 with the outer helical spline portion 307 of the shaft 300, the shaft 300 rotates along with the piston sleeve 306 as it moves and rotates linearly in the distal direction. As the piston sleeve 306 moves, fluid is discharged from the rod chamber 514 through the longitudinal channels 219, 220, the transverse channels 216, 218, and the ports 212, 214 of the first end cap 106.

[0078] Figure 8B A cross-sectional top view of a rotary actuator 100 according to an exemplary embodiment is shown, with the piston sleeve 306 retracted. When fluid is received at one or both ports 212, 214 of the first end cap 106, fluid is supplied to the rod chamber 514 within the cavity 304 via transverse channels 216, 218 and longitudinal channels 219, 220, and in the proximal axial direction (e.g., in...). Figure 5 (From center to left) A corresponding fluid force is applied to the piston sleeve 306. The corresponding fluid force causes the piston sleeve 306 to move longitudinally in the proximal axial direction until it reaches... Figure 8B The retracted position shown is where it is stopped by the second end cap 108.

[0079] Due to the engagement of the outer helical spline 312 of the piston sleeve 306 with the inner helical spline 309 of the ring gear 302 (which is fixed), the piston sleeve 306 rotates during its linear translation. Furthermore, due to the engagement of the inner helical spline 314 of the piston sleeve 306 with the outer helical spline portion 307 of the shaft 300, when the piston sleeve 306 moves and rotates linearly in the proximal direction, the shaft 300 rotates together with it in a second rotational direction (opposite to the first rotational direction). As the piston sleeve 306 moves, fluid is discharged from the head chamber 508 through the longitudinal channels 506, 512, the transverse channels 504, 510, and the ports 500, 502.

[0080] Thus, in response to the selective application of fluid to either side of the piston sleeve 306, the reciprocating longitudinal movement of the piston sleeve 306 within the tube 102 causes the shaft 300 to rotate clockwise or counterclockwise relative to the tube 102. For example, the rotational speed of the shaft 300 may depend on the pitch of the helical spline of the piston sleeve 306. For example, the rotational range of the shaft 300 corresponding to the stroke of the piston sleeve 306 may be 350 degrees.

[0081] The references to “far side” and “proximal side” are not intended to suggest a particular orientation of the components of the rotary actuator 100 relative to any surrounding environment. Rather, these directional terms are intended to facilitate the description of the interrelationships and functions among the various components of the rotary actuator 100.

[0082] As described above, when shaft 300 rotates, sensing target ring 334 rotates with it. The main sensor detects the rotational motion and position of shaft 300. A reference sensor can be added to provide a reference signal to compensate for any radial backlash or distortion. Rotary actuator 100 may also include sensing target ring 516 (similar to sensing target ring 334) mounted within a second end cap 108, and the second end cap 108 may have a corresponding sensor that detects the rotational position of sensing target ring 516 to achieve redundancy and enhance reliability.

[0083] Figure 9 A perspective bottom view of a rotary actuator 100 according to an exemplary embodiment is shown. As shown, the rotary actuator 100 includes a main sensor 600 mounted in a main sensor cavity 222 to interact with a sensor surface 404 of a sensing target ring 334. The rotary actuator 100 may also include a reference sensor 602 mounted through a reference sensor cavity 224 in a first end cap 106 to interact with a cylindrical portion 406 of the sensing target ring 334. The reference sensor 602 is also... Figure 5 As shown in -6.

[0084] In the event of failure of the main sensor 600 and / or the reference sensor 602, the second end cap 108 may similarly include a main sensor cavity 604, wherein the main sensor 606 is mounted to interact with a sensor surface (similar to sensor surface 404) of a sensing target ring 516 mounted within the second end cap 108. The second end cap 108 may also include a reference sensor cavity 608, in which a reference sensor 610 is mounted to interact with a cylindrical portion (similar to cylindrical portion 406) of the sensing target ring 516 of the second end cap 108.

[0085] Using this configuration, the rotary actuator 100 has sensor redundancy fully integrated within the end caps 106 and 108. Furthermore, as... Figure 9 As shown, the sensor is completely enclosed within end caps 106 and 108, and isolated from the pressure chamber (cavity 304). No sensor portion protrudes, and there are no exposed wires. Therefore, the sensor's electronic components can be completely enclosed within the weatherproof enclosure of end caps 106 and 108.

[0086] In one example, the main sensors 600, 606 and the reference sensors 602, 610 can be contact sensors, wherein the driven element contacts the sensor surface or circular surface of the respective sensing target ring. However, this document also envisions the use of non-contact sensors. Such non-contact sensors can be configured to measure the position of the sensing target ring 334, for example, based on interaction with sensor surface 404 without contacting sensor surface 404.

[0087] For example, the sensor may include an optical sensor probe having an optical disc that operates as a window for monitoring the sensor surface 404 of the sensing target ring 334. Such an optical sensor may have a light source that emits light through the optical disc. The optical sensor may also have a sensing element that receives light reflected from the sensor surface 404 and converts the light into an electronic signal. Specifically, the sensing element may measure the distance to the sensor surface 404 and then convert the measurement into an electrical signal indicating the distance and thus the rotational position of the sensing target ring 334.

[0088] Therefore, the term "interact" (with sensor surface 404 (or circular surface 407)) is used herein to encompass both contact with sensor surface 404 (or circular surface 407) and non-contact with sensor surface 404 (or circular surface 407) but configured to determine the rotational position of sensor surface 404 (or circular surface 407). Thus, although the main sensor 600 is described below as a contact sensor by way of example, it should be understood that a non-contact sensor may be used alternatively.

[0089] According to the example implementation, Figure 10A A perspective view of the main sensor 600 is shown. Figure 10B A top view of the main sensor 600 is shown, and Figure 10C A cross-sectional view of the main sensor 600 is shown. (Attached) Figures 10A to 10C They were described together.

[0090] The main sensor 600 includes an adapter 700. In one example, the adapter 700 may be constructed as a hexagonal body, such as... Figure 10A As shown. As an example, the adapter 700 may be made of machined stainless steel. The adapter 700 includes an external thread 702 (e.g., SAE-4 male thread) formed at the distal end of the adapter and configured to engage a corresponding internal thread in the first end cap 106 of the rotary actuator 100 to mount the main sensor 600 to the rotary actuator 100.

[0091] The adapter 700 may also include an internal thread 704 (e.g., a female SAE-4 threaded connection) at the proximal end of the adapter 700, such as... Figure 10C As shown. Adapter 700 is configured to operate as a guide for slave 706 of master sensor 600. Slave 706 may also be referred to as a tracer and is configured to move within master sensor 600 in an oscillating / reciprocating linear motion, as described in more detail below.

[0092] In one example, the follower 706 may be made of an injection-molded thermoplastic material (e.g., Delrin®). In one example, the follower 706 may have a distal end 707 at the distal end of the follower 706. For example, the distal end 707 is configured to contact the sensor surface 404 of the sensing target ring 334.

[0093] In this example, the end 707 can be configured as a spherical end. In this example, by being configured to have a spherical shape, the end 707 ensures smooth and consistent contact with the sensor surface 404 it follows. The spherical end also allows the follower 706 to maintain a consistent point of contact with the sensor surface 404, regardless of the orientation of the follower 706 or the position of the sensing target ring 334. This is because a sphere has the same curvature in all directions, which ensures that the contact point between the follower 706 and the sensor surface 404 remains constant, regardless of any small changes in the orientation of the follower 706 or the position of the sensing target ring 334.

[0094] The follower 706 has a cavity at its proximal end, and the main sensor 600 includes a magnet 708 disposed in the cavity. As an example, the magnet 708 may be a rare-earth magnet coupled to or held within the cavity of the follower 706 and configured to generate a magnetic field.

[0095] The main sensor 600 also includes a tube 710 configured for use with a magnetron in the main sensor 600. In one example, the tube 710 is a machined stainless steel part with external threads (e.g., SAE-4 male thread connection) at its distal end, said external threads being configured to engage the internal threads 704 of the adapter 700 to couple the tube 710 to the adapter 700. Figure 10C As shown, the tube 710 has an open distal end and a closed distal end, and the follower 706 is disposed through the open distal end such that the tube 710 and the adapter 700 form a longitudinal orifice 711, in which the follower 706 can oscillate / reciprocate in a linear motion.

[0096] The main sensor 600 also includes a spring 712 (e.g., a steel spring) disposed in a longitudinal aperture 711. The spring 712 is compressed between the enlarged portion 713 (e.g., a larger diameter section) of the follower 706 and an internal shoulder formed in the tube 710, as shown below. Figure 10C As shown. With this configuration, the proximal end of the spring 712 is fixed, while the distal end of the spring 712 abuts against the enlarged portion 713 of the follower 706, thereby applying a biasing force to the follower 706 in the distal direction. In this way, the spring 712 ensures that the end 707 of the follower 706 remains in contact with the surface that the follower 706 tracks during operation. The travel of the follower 706 in the distal direction is limited when the enlarged portion 713 contacts the inner shoulder 714 at the distal end of the adapter 700.

[0097] The main sensor 600 also includes an electronic module 716 mounted to the outer surface of the tube 710. The electronic module 716 may also be referred to as a "read head" and is configured to have a generally cylindrical body containing electronics that detect changes in the magnetic field as the follower 706 and the magnet 708 move linearly, thereby determining the linear position of the follower 706.

[0098] For example, electronic module 716 may include a printed circuit board (PCB) located within a molded frame, and such PCB may have electronics configured to resolve the magnetic field generated by magnet 708 to determine the linear position of follower 706. The PCB uses conductive traces, pads, and other features etched from one or more copper layers onto and / or between layers of a non-conductive substrate to mechanically support and electrically connect electronic components (e.g., microprocessors, integrated circuits, capacitors, resistors, etc.). Components are typically soldered to the PCB to electrically connect and mechanically secure them to the PCB.

[0099] In one example, magnet 708 operates as a magnetic target for electronic module 716, configured to measure changes in magnetic field strength. As follower 706 moves, magnet 708 moves accordingly, and the magnetic field strength sensed or measured by electronic module 716 changes. The position of follower 706 to which magnet 708 is attached can be correlated with the magnetic field strength measured by electronic module 716. Specifically, the processor of electronic module 716 can receive magnetic field strength information as magnet 708 moves, and can then determine the position of follower 706 based on the magnetic field strength information.

[0100] In the example, electronic module 716 has one or more coils that receive power and responsively generate a magnetic field that can interact with the magnetic field of magnet 708. When follower 706 and magnet 708 move, the magnetic field changes, and this change is sensed by the coils of electronic module 716. The coils of electronic module 716 can then generate one or more voltage signals indicating the change in magnetic field, which is correlated with the linear position of follower 706.

[0101] In one example, the main sensor 600 may include a retaining ring 718 and a washer 720, which are circumferentially mounted around the tube 710 and configured to axially hold the electronics module 716 relative to the tube 710. As an example, the retaining ring 718 may be a steel retaining ring mounted in a groove formed at the proximal end of the tube 710. The washer 720 may be a stainless steel flat washer used in conjunction with the retaining ring 718 to axially hold the electronics module 716 to the tube 710.

[0102] In one example, the main sensor 600 may include a spring 722 sandwiched between the electronics module 716 and the tube 710. The spring 722 is depicted as a wave spring; however, other types of biasing devices may be used. The spring 722 is configured to apply a biasing force on the electronics module 716 in a proximal direction toward the retaining ring 718 and the washer 720 to hold the electronics module 716 at a specific repeatable position relative to the follower 706 to compensate for manufacturing errors in the follower 706 or the electronics module 716.

[0103] The main sensor 600 also includes a first seal 726 (e.g., an elastomeric O-ring seal) disposed around the outer surface of the adapter 700. The first seal 726 is configured to seal the main sensor cavity 222 in the first end cap 106 of the rotary actuator 100, wherein the main sensor 600 is configured to prevent leakage from the fluid-filled cavity within the tube 102 or the first end cap 106 to the external environment of the rotary actuator 100. The main sensor 600 also includes a second seal 728 disposed in an annular groove formed in the tube 710 to seal the connection between the adapter 700 and the tube 710, thereby providing a pressure-sealed cavity in which the follower 706 linearly reciprocates.

[0104] Referring together to Figures 6-7 and 10A-10C, when the sensing target ring 334 rotates, the main sensor cavity 222 installed in the first end cap 106 (see Figure 6-7) Figure 3-4 The slave 706 of the master sensor 600 in the rotary actuator 100 contacts and tracks the sensor surface 404 of the sensing target ring 334 within the rotary actuator 100. The profile of the sensor surface 404 provides a radial surface position that varies continuously from the central axis of rotation of the shaft 300 of the rotary actuator 100. As the sensing target ring 334 rotates, the rotational motion of the sensing target ring 334 is translated into reciprocating motion of the slave 706 of the master sensor 600 due to the configuration of the sensor surface 404, and therefore the linear position of the slave 706 indicates the rotational position of the shaft 300 of the rotary actuator 100.

[0105] As an example for illustration, the master sensor 600 can be configured such that the total travel of the follower 706 (e.g., the total axial movement of the follower between its highest and lowest positions on sensor surface 404) is approximately 0.18 inches, corresponding to a 180-degree rotation of the sensing target ring 334. The master sensor 600 can be configured to detect movements as small as one-tenth of an inch (0.0001 inch). In this example, the master sensor 600 can determine the rotational position of the sensing target ring 334 and the shaft 300 with an accuracy of 0.1 degrees.

[0106] In some examples, due to manufacturing errors, the assembly of shaft 300, piston sleeve 306, and sensing target ring 334 may be offset from the center of tube 102. As an example, a gap (e.g., 0.005-0.008 inches) may exist between the outer surface of sensing target ring 334 (and the outer surface of piston head 308) and the inner surface of tube 102. Therefore, some radial “play” or movement may exist within the assembly of shaft 300, piston sleeve 306, and sensing target ring 334 within cavity 304 of tube 102.

[0107] In these examples, this radial clearance can cause the position of the follower 706 of the master sensor 600 to provide an inaccurate indication of the rotational position of the shaft 300. For example, if the assembly is displaced downward in the cavity 304, the follower 706 may extend into the cavity 304, which could inaccurately or incorrectly indicate that the sensor surface 404 has rotated.

[0108] In another example, components of the rotary actuator 100, such as tube 102, sensing target ring 334, or piston sleeve 306, may deform due to the high fluid pressure in cavity 304 (e.g., pressure levels up to 5000 psi). For example, the inner surface of tube 102 may not remain circular under high pressure. Such deformation can also affect the accuracy of the main sensor 600 in indicating the rotational position of shaft 300.

[0109] In these examples, it may be desirable to configure the rotary actuator 100 to have a reference sensor that provides a baseline or reference value for the location of the internal components of the rotary actuator 100. This reference value can be used to adjust or modify the rotational position determined by the main sensor 600 to compensate for radial clearance or deformation. In particular, the reference value can be subtracted from the measurement (value) of the main sensor 600 to counteract the effects of any radial clearance or distortion / deformation.

[0110] Therefore, the rotary actuator 100 may include a reference sensor 602, which is mounted within a first end cap 106 in a reference sensor cavity 224 and configured to interact with the cylindrical portion 406 of the sensing target ring 334. As described above, the circular surface 407 of the cylindrical portion 406 has a constant radius, and points on the circular surface 407 are equidistant from the center of the shaft 300. A follower (similar to follower 706) of the reference sensor 602 contacts the cylindrical portion 406, and thus the reference sensor 602 can measure and provide corresponding sensor information indicating the position of the circular surface 407 of the cylindrical portion 406 concentric with the shaft 300.

[0111] In the example, the measured value or position of the circular surface 407 of the cylindrical portion 406 detected by the follower of the reference sensor 602 can be subtracted from the measured value of the position of the follower of the master sensor 600 to eliminate any inaccuracies caused by unintended movement (e.g., radial clearance) of the sensing target ring 334. Eliminating such external radial movement (when the sensing target ring 334 is subjected to radial deflection of the follower component assembly clearance relative to the tube 102 or under large external loads) can produce a more accurate and repeatable angular position resolution of the axis 300 determined by the master sensor 600.

[0112] Advantageously, such as Figure 7 As shown, the cylindrical portion 406 is positioned adjacent to the sensor surface 404. This proximity between the sensor surface 404, tracked by the follower 706 of the master sensor 600, and the circular surface 407, tracked by the follower of the reference sensor 602, allows for more accurate determination of the rotational position of the shaft 300 after eliminating any radial backlash or deformation. In particular, positioning the sensor surface 404 adjacent to the circular surface 407 and permanently fixing both to the sensing target ring 334 allows for instantaneous subtraction of the output value of the master sensor 600, thus canceling out any positional changes of the sensing target ring 334 relative to the tube 102.

[0113] Furthermore, rotary pressure seals 338 and 340 isolate the primary sensor 600 and reference sensor 602, mounted in the first end cap 106, from the high-pressure fluid in the cavity 304 within the tube 102. A corresponding rotary pressure seal on the sensing target ring 516 also isolates the primary sensor 606 and reference sensor 610 (in an example where such sensors are mounted to the second end cap 108 for redundancy) from the high-pressure fluid.

[0114] Figure 11 This is a flowchart of a method 800 for operating a rotary actuator 100 according to an example embodiment. Method 800 may include one or more operations or actions as shown in one or more of blocks 802-808. Although the blocks are shown in sequential order, in some cases these blocks may be performed in parallel, and / or in an order different from that described herein. Furthermore, various blocks may be combined into fewer blocks, divided into additional blocks, and / or removed based on desired implementation methods.

[0115] Furthermore, for method 800 and other processes and operations disclosed herein, the flowchart illustrates one possible implementation of the operation of this example. In this regard, some boxes may represent modules, segments, or portions of program code, which include one or more instructions executable by a processor (e.g., the processor of the main sensor 600 or the controller of the rotary actuator 100) for implementing specific logical operations or steps in the process. The program code may be stored on any type of computer-readable medium or memory, such as storage devices including disks or hard disks. Computer-readable media may include non-transitory computer-readable media or memory, such as computer-readable media that store data for a short period of time, such as register memory, processor cache, and random access memory (RAM). Computer-readable media may also include non-transitory media or memory, such as auxiliary or persistent long-term storage devices, such as read-only memory (ROM), optical disks or magnetic disks, and optical disc read-only memory (CD-ROM). Computer-readable media may also be any other volatile or non-volatile storage system. For example, a computer-readable medium may be considered a computer-readable storage medium, a tangible storage device, or other article of manufacture. Furthermore, for method 800 and other processes and operations disclosed herein, Figure 11 One or more boxes in the diagram can represent circuits or digital logic arranged to perform specific logical operations during the process.

[0116] At block 802, method 800 includes providing a fluid flow to a rotary actuator 100, wherein the rotary actuator 100 has: (i) a tube 102, (ii) a first end cap 106 coupled to an end of the tube 102, wherein the first end cap 106 has a main sensor cavity 222, (iii) a shaft 300 disposed in the tube 102, wherein the shaft 300 is rotatable within the tube 102 when a fluid flow is provided within the tube 102, (iv) a sensing target ring 334 rotatably coupled to the shaft 300, wherein the sensing target ring 334 has a sensor surface 404 and an annular groove (e.g., a first annular groove 408), in which a rotary pressure seal 338 is disposed, and (v) a main sensor 600 mounted in the main sensor cavity of the end cap to interact with the sensor surface.

[0117] At block 804, method 800 includes rotating a shaft in response to providing fluid flow within the tube, thereby causing a sensing target ring to rotate together with the shaft.

[0118] At block 806, method 800 includes generating sensor information from a master sensor based on interaction with a sensor surface, wherein a rotating pressure seal isolates the master sensor relative to the high-pressure fluid in the tube.

[0119] At block 808, method 800 includes determining the rotational position of the sensing target ring and shaft based on sensor information from the master sensor.

[0120] Method 800 may also include any operation described throughout this document.

[0121] The above detailed description, with reference to the accompanying drawings, illustrates various features and operations of the disclosed system. The illustrative embodiments described herein are not intended to be limiting. Certain aspects of the disclosed system can be arranged and combined in a variety of different configurations, all of which are considered herein.

[0122] Furthermore, unless the context otherwise requires, the features shown in each figure can be used in combination with each other. Therefore, the figures should generally be considered as component aspects of one or more overall embodiments, and it should be understood that not all features shown are necessary for every embodiment.

[0123] Furthermore, any enumeration of elements, blocks, or steps in this specification or claims is for clarity purposes. Therefore, such enumeration should not be construed as requiring or implying that these elements, blocks, or steps are performed in a particular arrangement or in a particular order.

[0124] Furthermore, devices or systems can be used or configured to perform the functions illustrated in the accompanying drawings. In some cases, components of the devices and / or systems can be configured to perform functions such that the components are actually configured and constructed (using hardware and / or software) to achieve this performance. In other examples, components of the devices and / or systems can be arranged to be suitable, capable of, or adapted to perform functions, such as when operating in a particular manner.

[0125] The terms “substantially” or “about” mean that the listed characteristic, parameter, or value does not need to be precisely achieved, but rather that deviations or variations (including, for example, tolerances, measurement errors, measurement accuracy limitations, and other factors known to those skilled in the art) may occur in a quantity that does not preclude the effect that the characteristic is intended to provide.

[0126] The arrangements described herein are for illustrative purposes only. Therefore, those skilled in the art will understand that other arrangements and other elements (e.g., machines, interfaces, operations, sequences, and operational groups, etc.) can be used alternatively, and some elements can be omitted entirely depending on the desired results. Furthermore, many of the elements described are functional entities that can be implemented as discrete or distributed components or combined with other components in any suitable combination and location.

[0127] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The aspects and embodiments disclosed herein are for illustrative purposes and not restrictive, and the true scope is indicated by the appended claims and the full scope of their equivalents. Furthermore, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0128] Therefore, embodiments of this disclosure may relate to one of the exemplary embodiments (EEEs) listed below.

[0129] EEE 1 is a rotary actuator comprising: a tube; an end cap coupled to an end of the tube, wherein the end cap has a main sensor cavity; a shaft disposed in the tube, wherein the shaft is rotatable within the tube when fluid flow is provided within the tube; a sensing target ring rotatably coupled to the shaft, wherein the sensing target ring has a sensor surface and an annular groove, and a rotary pressure seal is disposed in the annular groove; and a main sensor mounted in the main sensor cavity of the end cap, wherein the main sensor interacts with the sensor surface of the sensing target ring to provide sensor information indicating the rotational position of the sensing target ring and the shaft, and wherein the rotary pressure seal isolates the main sensor from the high-pressure fluid in the tube.

[0130] EEE 2 is a rotary actuator of EEE 1, wherein the sensing target ring is at least partially disposed within the end cap, such that the sensing target ring is radially clamped between the shaft and the end cap.

[0131] EEE 3 is a rotary actuator of any of EEE 1-2, wherein the sensor surface of the sensing target ring provides a continuously varying position from the center of the shaft as the sensing target ring rotates together with the shaft.

[0132] EEE 4 is a rotary actuator of any of EEE 1-3, wherein the sensing target ring further includes a circular surface concentric with the shaft, wherein the end cap further includes a reference sensor cavity, and wherein the rotary actuator further includes: a reference sensor mounted in the reference sensor cavity of the end cap, wherein the reference sensor interacts with the circular surface such that the reference sensor provides corresponding sensor information indicating the position of the circular surface, and wherein the corresponding sensor information of the reference sensor is used to modify the sensor information of the main sensor to determine the rotational position of the sensing target ring and the shaft.

[0133] EEE 5 is a rotary actuator of any one of EEE 1-4, wherein the end cap is a first end cap coupled to a first end of the tube, wherein the sensing target ring is a first sensing target ring, and wherein the rotary actuator further includes: a second end cap coupled to a second end of the tube, wherein the second end cap has a corresponding main sensor cavity; and a second sensing target ring rotatably coupled to the shaft, wherein the second sensing target ring has a corresponding sensor surface and a corresponding annular groove, wherein a corresponding rotary pressure seal is disposed in the annular groove.

[0134] EEE 6 is a rotary actuator of EEE 5, wherein the main sensor is a first main sensor, and wherein the rotary actuator further includes: a second main sensor mounted in a corresponding main sensor cavity of a second end cap, wherein the second main sensor interacts with a corresponding sensor surface of a second sensing target ring to provide sensor information indicating a corresponding rotational position of the second sensing target ring, and wherein a corresponding rotational pressure seal isolates the second main sensor from the high-pressure fluid in the tube.

[0135] EEE 7 is a rotary actuator of any one of EEE 1-6, wherein the annular groove of the sensing target ring is a first annular groove, wherein the rotary pressure seal is a first rotary pressure seal, and wherein the sensing target ring has a second annular groove axially spaced from the first annular groove, and the second rotary pressure seal is disposed in the second annular groove.

[0136] EEE 8 is a rotary actuator of any of EEE 1-7, and further includes: an output hub rotatably coupled to a shaft; and a wear-resistant ring radially mounted between the output hub and the end cap, such that the wear-resistant ring operates as a radial bearing to facilitate rotation of the output hub relative to the end cap.

[0137] EEE 9 is a rotary actuator of any of EEE 1-8, and further includes: an output hub rotatably coupled to a shaft; and a thrust bearing axially mounted between the output hub and the end cap.

[0138] EEE 10 is a rotary actuator of any of EEE 1-9, wherein the shaft has a first threaded portion and a second threaded portion formed in the end of the shaft, and wherein the rotary actuator further includes: an output hub rotatably coupled to the shaft; a retaining ring threadedly engaging the first threaded portion of the shaft and mating with the output hub; and a locking ring threadedly engaging the second threaded portion of the shaft and mating with the retaining ring.

[0139] EEE 11 is a rotary actuator of EEE 10, wherein the second threaded portion has a rotational direction opposite to that of the first threaded portion, such that the rotation of the shaft further tightens the locking ring and prevents the retaining ring and output hub from loosening.

[0140] EEE 12 is a rotary actuator of any of EEE 1-11, wherein the end cap has (i) one or more ports for receiving fluid from a fluid source, and (ii) one or more channels fluidly coupled to the one or more ports for supplying fluid received at the one or more ports into the tube, and wherein the rotary actuator further includes: a piston sleeve mounted to the shaft such that the fluid supplied into the tube exerts a fluid force on the piston sleeve, causing the piston sleeve to move linearly within the tube, thereby rotating the shaft.

[0141] EEE 13 is a rotary actuator of EEE 12, and also includes: a ring gear coupled to a tube and having an internal helical spline projecting radially inward within the tube, wherein the piston sleeve includes an external helical spline engaging with the internal helical spline of the ring gear, such that linear movement of the piston sleeve causes the piston sleeve to rotate relative to the tube.

[0142] EEE 14 is a rotary actuator of EEE 13, wherein the piston sleeve also includes a corresponding internal helical spline that engages with an external helical spline portion formed in the shaft, such that rotation of the piston sleeve causes the shaft to rotate relative to the tube.

[0143] EEE 15 is a rotary actuator of any of EEE 12-14, wherein the end cap operates as a stop for the piston sleeve.

[0144] EEE 16 is a rotary actuator of any of EEE 12-15, wherein the end cap is a first end cap, wherein a piston sleeve divides a cavity within a tube into a head chamber and a rod chamber, and wherein the rotary actuator further comprises: a second end cap having (i) one or more corresponding ports for receiving fluid from the fluid source, and (ii) one or more corresponding channels fluidly coupled to the one or more corresponding ports for providing fluid received at the one or more corresponding ports into the tube, wherein: fluid received at the one or more ports of the first end cap is provided to the head chamber through the one or more channels, thereby driving the piston sleeve in a first direction until the piston sleeve reaches the second end cap, wherein fluid in the rod chamber is discharged through the one or more corresponding channels and one or more corresponding ports of the second end cap, and fluid received at the one or more corresponding ports of the second end cap is provided to the rod chamber through the one or more corresponding channels, thereby driving the piston sleeve in a second direction until the piston sleeve reaches the first end cap, wherein fluid in the head chamber is discharged through the one or more channels and one or more ports of the first end cap.

[0145] EEE 17 is a rotary actuator of any of EEE 12-16, wherein the sensing target ring has one or more timing marks that facilitate mounting the sensing target ring to the shaft at a specific rotational position.

[0146] EEE 18 is a method of operating a rotary actuator of any of EEE 1-17. For example, the method includes: providing a fluid flow to the rotary actuator, wherein the rotary actuator has: (i) a tube; (ii) an end cap coupled to an end of the tube, wherein the end cap has a main sensor cavity; (iii) a shaft disposed in the tube, wherein the shaft is rotatable within the tube when a fluid flow is provided within the tube; (iv) a sensing target ring rotatably coupled to the shaft, wherein the sensing target ring has a sensor surface and an annular groove, a rotary pressure seal disposed in the annular groove; and (v) a main sensor mounted in the main sensor cavity of the end cap to interact with the sensor surface; rotating the shaft in response to the fluid flow being provided within the tube, thereby causing the sensing target ring to rotate with the shaft; generating sensor information from the main sensor based on the interaction with the sensor surface, wherein the rotary pressure seal isolates the main sensor relative to the high-pressure fluid in the tube; and determining the rotational position of the sensing target ring and the shaft based on the sensor information from the main sensor.

[0147] EEE 19 is a method of EEE 18, wherein the sensing target ring further includes a circular surface concentric with the shaft, wherein the end cap further includes a reference sensor cavity, and wherein the rotary actuator further includes a reference sensor mounted in the reference sensor cavity of the end cap to interact with the circular surface, and wherein the method further includes: generating corresponding sensor information by the reference sensor based on the interaction with the circular surface, wherein a rotary pressure seal isolates the reference sensor from the high-pressure fluid in the tube; and adjusting the rotational position of the sensing target ring and the shaft determined by sensor information from the main sensor based on the corresponding sensor information generated by the reference sensor.

[0148] EEE 20 is a method of any one of EEE 18-19, wherein the end cap is a first end cap coupled to a first end of the tube, wherein the sensing target ring is a first sensing target ring, wherein the master sensor is a first master sensor, wherein the rotary actuator further includes: (i) a second end cap coupled to a second end of the tube, wherein the second end cap has a corresponding master sensor cavity, (ii) a second sensing target ring rotatably coupled to a shaft, wherein the second sensing target ring has a corresponding sensor surface and a corresponding annular groove, wherein a corresponding rotary pressure seal is disposed in the corresponding annular groove, and (iii) a second master sensor mounted in the corresponding master sensor cavity of the second end cap to interact with the corresponding sensor surface, and wherein the method further includes: generating sensor information from the second master sensor based on the interaction with the corresponding sensor surface, wherein the corresponding rotary pressure seal isolates the second master sensor from the high-pressure fluid in the tube; and determining the rotational position of the second sensing target ring and the shaft based on the sensor information from the second master sensor.

Claims

1. A rotary actuator, comprising: Tube; An end cap coupled to the end of the tube, wherein the end cap has a main sensor cavity; A shaft disposed in the tube, wherein the shaft is rotatable within the tube when a fluid flow is provided within the tube; A sensing target ring rotatably coupled to the shaft, wherein the sensing target ring has a sensor surface and an annular groove, and a rotary pressure seal is disposed in the annular groove; as well as A main sensor is mounted in the main sensor cavity of the end cap, wherein the main sensor interacts with the sensor surface of the sensing target ring to provide sensor information indicating the rotational position of the sensing target ring and the shaft, and wherein the rotational pressure seal isolates the main sensor relative to the high-pressure fluid in the tube.

2. The rotary actuator of claim 1, wherein, The sensing target ring is at least partially disposed within the end cap, such that the sensing target ring is radially sandwiched between the shaft and the end cap.

3. The rotary actuator of claim 1, wherein, As the sensing target ring rotates together with the shaft, the sensor surface of the sensing target ring provides a continuously changing position from the center of the shaft.

4. The rotary actuator according to claim 1, wherein, The sensing target ring further includes a circular surface concentric with the shaft, wherein the end cap further includes a reference sensor cavity, and wherein the rotary actuator further includes: A reference sensor is mounted in a reference sensor cavity of the end cap, wherein the reference sensor interacts with the circular surface such that the reference sensor provides corresponding sensor information indicating the position of the circular surface, and wherein the corresponding sensor information of the reference sensor is used to modify the sensor information of the main sensor to determine the rotational position of the sensing target ring and the shaft.

5. The rotary actuator according to claim 1, wherein, The end cap is a first end cap coupled to a first end of the tube, wherein the sensing target ring is a first sensing target ring, and wherein the rotary actuator further includes: A second end cap, coupled to a second end of the tube, wherein the second end cap has a corresponding main sensor cavity; and A second sensing target ring is rotatably coupled to the shaft, wherein the second sensing target ring has a corresponding sensor surface and a corresponding annular groove, and a corresponding rotational pressure seal is disposed in the corresponding annular groove.

6. The rotary actuator according to claim 5, wherein, The main sensor is a first main sensor, and the rotary actuator further includes: A second master sensor is mounted in a corresponding master sensor cavity of the second end cap, wherein the second master sensor interacts with a corresponding sensor surface of the second sensing target ring to provide sensor information indicating a corresponding rotational position of the second sensing target ring, and wherein the corresponding rotational pressure seal isolates the second master sensor relative to the high-pressure fluid in the tube.

7. The rotary actuator according to claim 1, wherein, The annular groove of the sensing target ring is a first annular groove, the rotary pressure seal is a first rotary pressure seal, and the sensing target ring has a second annular groove axially spaced from the first annular groove, the second rotary pressure seal being disposed in the second annular groove.

8. The rotary actuator according to claim 1, further comprising: The output hub is rotatably coupled to the shaft; as well as A wear-resistant ring is radially mounted between the output hub and the end cap, such that the wear-resistant ring operates as a radial bearing to facilitate rotation of the output hub relative to the end cap.

9. The rotary actuator according to claim 1, further comprising: The output hub is rotatably coupled to the shaft; as well as A thrust bearing is axially mounted between the output hub and the end cover.

10. The rotary actuator according to claim 1, wherein, The shaft has a first threaded portion and a second threaded portion formed into an end of the shaft, and the rotary actuator further includes: The output hub is rotatably coupled to the shaft; A retaining ring, which is threadedly engaged with a first threaded portion of the shaft and abuts against the output hub; and A locking ring, which is threaded into a second threaded portion of the shaft and abuts against the retaining ring.

11. The rotary actuator according to claim 10, wherein, The second threaded portion has a rotational direction opposite to that of the first threaded portion, such that rotation of the shaft further tightens the locking ring and prevents the retaining ring and the output hub from loosening.

12. The rotary actuator according to claim 1, wherein, The end cap has (i) one or more ports for receiving fluid from a fluid source, and (ii) one or more channels fluidly coupled to the one or more ports for providing the fluid received at the one or more ports into the tube, and wherein the rotary actuator further includes: A piston sleeve is mounted to the shaft such that fluid disposed in the tube exerts a fluid force on the piston sleeve, causing the piston sleeve to move linearly within the tube, thereby rotating the shaft.

13. The rotary actuator according to claim 12, further comprising: A ring gear coupled to the tube and having an internal helical spline projecting radially inward within the tube, wherein the piston sleeve includes an external helical spline engaging with the internal helical spline of the ring gear, such that linear movement of the piston sleeve causes the piston sleeve to rotate relative to the tube.

14. The rotary actuator according to claim 13, wherein, The piston sleeve also includes a corresponding internal helical spline that engages with an external helical spline portion formed in the shaft, such that rotation of the piston sleeve causes the shaft to rotate relative to the tube.

15. The rotary actuator according to claim 12, wherein, The end cap operates as a stop for the piston sleeve.

16. The rotary actuator according to claim 12, wherein, The end cap is a first end cap, wherein the piston sleeve divides the cavity within the tube into a head chamber and a rod chamber, and wherein the rotary actuator further includes: A second end cap having (i) one or more corresponding ports for receiving fluid from the fluid source, and (ii) one or more corresponding channels fluidly coupled to the one or more corresponding ports for providing the fluid received at the one or more corresponding ports into the pipe, wherein: Fluid received at one or more ports of the first end cap is supplied to the head chamber through one or more channels, thereby driving the piston sleeve in a first direction until the piston sleeve reaches the second end cap, wherein fluid in the rod chamber is discharged through one or more corresponding channels and one or more corresponding ports of the second end cap, and Fluid received at one or more corresponding ports of the second end cap is supplied to the rod chamber through one or more corresponding channels, thereby driving the piston sleeve in a second direction until the piston sleeve reaches the first end cap, wherein fluid in the head chamber is discharged through one or more channels and one or more ports of the first end cap.

17. The rotary actuator according to claim 12, wherein, The sensing target ring has one or more timing marks that facilitate mounting the sensing target ring to the shaft at a specific rotational position.

18. A method comprising: A fluid flow is provided to a rotary actuator, wherein the rotary actuator has: (i) a tube, (ii) an end cap coupled to an end of the tube, wherein the end cap has a main sensor cavity, (iii) a shaft disposed in the tube, wherein the shaft is rotatable within the tube when a fluid flow is provided therein, (iv) a sensing target ring rotatably coupled to the shaft, wherein the sensing target ring has a sensor surface and an annular groove, a rotary pressure seal disposed in the annular groove, and (v) a main sensor mounted in the main sensor cavity of the end cap to interact with the sensor surface; In response to providing the fluid flow within the tube, the shaft is rotated, thereby causing the sensing target ring to rotate together with the shaft; Sensor information is generated by the main sensor based on its interaction with the sensor surface, wherein the rotary pressure seal isolates the main sensor from the high-pressure fluid in the tube; as well as Based on sensor information from the main sensor, the rotational positions of the sensing target ring and the shaft are determined.

19. The method of claim 18, wherein, The sensing target ring further includes a circular surface concentric with the axis, wherein the end cap further includes a reference sensor cavity, and wherein the rotary actuator further includes a reference sensor mounted in the reference sensor cavity of the end cap to interact with the circular surface, and wherein the method further includes: The reference sensor generates corresponding sensor information based on its interaction with the circular surface, wherein the rotating pressure seal isolates the reference sensor relative to the high-pressure fluid in the tube; and Based on the corresponding sensor information generated by the reference sensor, the rotational positions of the sensing target ring and the shaft, determined by the sensor information from the main sensor, are adjusted.

20. The method of claim 18, wherein, The end cap is a first end cap coupled to a first end of the tube, wherein the sensing target ring is a first sensing target ring, wherein the main sensor is a first main sensor, and wherein the rotary actuator further includes: (i) a second end cap coupled to a second end of the tube, wherein the second end cap has a corresponding main sensor cavity, (ii) a second sensing target ring rotatably coupled to the shaft, wherein the second sensing target ring has a corresponding sensor surface and a corresponding annular groove, wherein a corresponding rotary pressure seal is disposed in the corresponding annular groove, and (iii) a second main sensor, the second main sensor being mounted in a corresponding main sensor cavity of the second end cap to interact with the corresponding sensor surface, and wherein the method further includes: Sensor information is generated by the second main sensor based on its interaction with the corresponding sensor surface, wherein the corresponding rotary pressure seal isolates the second main sensor relative to the high-pressure fluid in the tube; and Based on sensor information from the second main sensor, the rotational positions of the second sensing target ring and the shaft are determined.

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