Actuator Fault Fixing System

Abstract

An actuator assembly including a fault fixing system is provided. The actuator assembly includes an output shaft, an input drive assembly, and a piston assembly. The piston assembly includes a body that surrounds a piston, and the piston is movable within the body. The body defines a first end and a second end opposite thereto, and the piston is movable within the body between the first end and the second end. The piston assembly includes a spring disposed at the first end, between the body and the piston. The piston assembly includes a friction mechanism disposed at a second end of the piston opposite the first end. An adjustable region is defined within the body, between the second end of the piston and the input drive assembly.

Description

[0001] This application is a divisional application of the patent application with the application number 201911120295.5 and the invention title "Actuator Fault Fixing System" filed on November 15, 2019. Technical Field

[0002] This subject matter generally relates to a fault fixing structure for an actuator assembly. Background Art

[0003] An actuator assembly, such as a rotary actuator assembly, can change position after a failure of an input signal or a pressure source, and thus move from the last commanded position before the failure. Thus, in certain devices such as turbines, an actuator assembly coupled to a variable vane assembly may undesirably cause the vane assembly to move after a failure of the actuator assembly, for example, after the loss of an electrical input signal or a power pressure source. Therefore, a failure of the actuator assembly may exacerbate a failure at the turbine by undesirably allowing an uncommanded change in the vane angle due to the loss of control of the actuator assembly. Such an uncommanded change may adversely affect the operation of the turbine, including stall or surge.

[0004] Additionally or alternatively, there is a need for a fault fixing system that reduces weight and complexity compared to known systems, which may include multiple components separate from the actuator assembly or the housing.

[0005] Accordingly, there is a need for a fault fixing system for an actuator assembly that prohibits or mitigates undesired movement of the system after an input control failure. Summary of the Invention

[0006] Aspects and advantages of the present invention will be set forth in part in the following description, or may be obvious from the description, or may be learned by practicing the present invention.

[0007] One aspect of the present disclosure is directed to an actuator assembly including a fault fixing system. The actuator assembly includes an output shaft, an input drive assembly, and a piston assembly. The piston assembly includes a body that surrounds a piston, and the piston is movable within the body. The body defines a first end and a second end opposite thereto, and the piston is movable within the body between the first end and the second end. The piston assembly includes a spring disposed at the first end, between the body and the piston. The piston assembly includes a friction mechanism disposed at a second end of the piston opposite the first end. An adjustable region is defined within the body, between the second end of the piston and the input drive assembly.

[0008] In one embodiment, the body defines a groove that extends laterally between the first end and the second end, wherein the piston is at least partially disposed within the groove to prevent the piston from rotating.

[0009] In another embodiment, the friction mechanism includes a friction disk configured to engage the piston and the input drive assembly together.

[0010] In yet another embodiment, the friction mechanism includes a serrated geometry at the servo piston and the input shaft, wherein the serrated geometry is configured to statically couple the servo piston and the input drive assembly together.

[0011] In still another embodiment, the body defines an opening therethrough that is in fluid communication with the region between the piston and the input drive assembly.

[0012] In various embodiments, the actuator assembly further includes a control valve assembly configured to supply and discharge motive fluid to and from the region between the piston and the input drive assembly. In one embodiment, the control valve assembly is configured to supply motive fluid to the region between the piston and the input drive assembly that is equal and opposite to the force exerted by the spring toward the input drive assembly. In another embodiment, the control valve assembly is configured to discharge motive fluid from the region between the piston and the input drive assembly after loss of signal to the control valve assembly. In one embodiment, the piston assembly is configured to engage the input drive assembly via the friction mechanism after motive fluid is discharged from the region between the piston and the input drive assembly.

[0013] In one embodiment, the piston defines one or more of a stop ring or a servo controller piston.

[0014] Another aspect of the present disclosure is directed to an apparatus for fail-safe actuation. The apparatus includes an actuator assembly including an output shaft, an input drive assembly, and a piston assembly. The piston assembly includes a body surrounding a piston that is movable within the body. The body defines a first end and a second end opposite thereto, and the piston is movable within the body between the first end and the second end. The piston assembly includes a spring disposed at the first end, between the body and the piston. The piston assembly includes a friction mechanism disposed at the second end of the piston opposite the first end. An adjustable region is defined within the body, between the second end of the piston and the input drive assembly. The actuator assembly further includes a control valve assembly configured to supply and discharge motive fluid to and from the region between the piston and the input drive assembly. The apparatus includes a controller configured to provide a signal to the control valve of the actuator assembly.

[0015] In one embodiment, the controller provides a signal to the control valve assembly to close the input opening at the control valve assembly. Closing the input opening holds the motive fluid at the region between the piston and the input drive assembly that is equal and opposite to the force exerted by the spring toward the input drive assembly.

[0016] In various embodiments, the control valve assembly is configured to discharge motive fluid from the area between the piston and the input drive assembly after loss of signal from the controller to the control valve assembly. In one embodiment, the control valve assembly is configured to close the input opening at the control valve assembly to prohibit motive fluid from the area between the piston and the input drive assembly. In another embodiment, the piston assembly is configured to engage the input drive assembly via a friction mechanism after the motive fluid is discharged from the area between the piston and the input drive assembly.

[0017] In one embodiment, the body defines a groove that extends laterally between a first end and a second end, and wherein the piston is at least partially disposed within the groove to prevent rotation of the piston.

[0018] In another embodiment, the friction mechanism includes a friction disk configured to engage the piston and the input drive assembly together.

[0019] In yet another embodiment, the friction mechanism includes a serrated geometry at the servo piston and the input shaft, wherein the serrated geometry is configured to statically couple the servo piston and the input drive assembly together.

[0020] In still another embodiment, the body defines an opening therethrough that is in fluid communication with the area between the piston and the input drive assembly.

[0021] In yet still another embodiment, the piston defines one or more of a stop ring or a servo controller piston.

[0022] These and other features, aspects, and advantages of the present invention will become better understood by reference to the following description and the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In the description of the drawings, for a person of ordinary skill in the art, a complete and enabling disclosure of the present invention, including its best mode, is set forth, in the drawings:

[0024] Figure 1A is an exemplary embodiment depicting an actuator assembly separated from an input drive assembly according to one aspect of the present disclosure;

[0025] Figure 1B is an exemplary embodiment depicting an actuator assembly engaged with an input drive assembly according to one aspect of the present disclosure; Figure 1A of the actuator assembly;

[0026] Figure 2Ais an exemplary embodiment depicting an actuator assembly separated from an input drive assembly according to one aspect of the present disclosure;

[0027] Figure 2B is depicting an actuator assembly engaged with an input drive assembly according to one aspect of the present disclosure Figure 2A of an exemplary embodiment; and

[0028] Figure 3 is a schematic cross-sectional view of an exemplary device including an embodiment of an actuator assembly according to one aspect of the present disclosure.

[0029] The reuse of reference characters in this specification and the drawings is intended to represent the same or similar features or elements of the present invention. Detailed Description

[0030] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each embodiment is provided to explain the present invention, not to limit it. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features shown or described as part of one embodiment can be used with another embodiment to yield yet another embodiment. Accordingly, the present invention is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0031] As used herein, the terms "first," "second," and "third" may be used interchangeably to distinguish one component from another and are not intended to denote the position or importance of a single component.

[0032] The terms "upstream" and "downstream" refer to the relative direction with respect to the flow of fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction towards which the fluid flows.

[0033] Approximations recited herein may include margins based on more than one measuring device used in the art, such as, but not limited to, a percentage of the full-scale measurement range of a measuring device or sensor. Alternatively, approximations recited herein may include a margin of 10% greater than the upper limit value or 10% less than the lower limit value of the lower limit value.

[0034] Generally provides an embodiment of an actuator assembly that includes a fail-safe system that can inhibit or mitigate undesirable movement of the actuator system after an input control failure. The actuator assembly shown and described herein provides a system within a rotary actuator assembly to inhibit or mitigate undesirable movement of a rotary actuator output shaft after an input control signal failure. Embodiments of the actuator assembly include a stop ring or servo piston keyed or slotted into a surrounding body to prevent rotation of the ring or piston. A spring is coupled to a first end of the piston and maintains the piston loaded against a vane shaft or input drive assembly. A control valve assembly, such as a control solenoid valve, supplies motive fluid to a second end of the piston opposite the first end to balance the load applied from the spring during fault-free operation of the actuator assembly.

[0035] After loss of signal from the control valve assembly, motive fluid to the second end of the piston is interrupted and the spring is allowed to apply a compressive force to move the piston against the vane shaft or input drive assembly. A friction mechanism, such as a friction disk or tooth geometry, engages the input drive assembly at the second end of the piston. The piston, now engaged with the input drive assembly and keyed or slotted into the surrounding body, prevents rotation of the input drive assembly and thus prevents rotation of the output shaft. The minimum distance between the second end of the piston and the input drive assembly mitigates the amount of movement that may occur after a control signal failure. Thus, undesirable movement of a device attached to the actuator assembly, such as an undesirable movement of a vane assembly, is mitigated or inhibited. Additionally or alternatively, the last commanded position of the output shaft is substantially maintained after loss of the control signal.

[0036] When incorporated into a turbine, embodiments of the actuator assembly shown and described herein can mitigate turbine stall, surge, or other undesirable operations that may be caused by an undesirable change in vane angle at the vane assembly after loss of a control signal.

[0037] Now referring to the drawings, Figures 1A-1B and Figures 2A-2BAn exemplary embodiment of an actuator assembly 90 in accordance with aspects of the present disclosure is provided. The actuator assembly 90 includes an output shaft 110 coupled to an input drive assembly 130. The output shaft 110 extends through a piston assembly 120 within a surrounding body 115. The body 115 defines a first end 123 that is laterally separated from a second end 125 with a stop ring or servo controller piston 124 therebetween. The piston assembly 120 is removably coupled to the input drive assembly 130 at the second end 125. In various embodiments, the input drive assembly 130 includes an actuator mechanism 132 and an input shaft 134 that is removably coupled to the piston assembly 120. In one embodiment, the actuator mechanism 132 includes an actuator vane assembly that defines a rotary type actuator driven by a power fluid. The power fluid can include a lubricant or a hydraulic fluid, or a pneumatic fluid, or one or more of another suitable power fluid that actuates the input drive assembly 130 and rotates or otherwise displaces the output shaft 110.

[0038] The piston assembly 120 including the stop ring or servo controller piston 124 is capable of moving within the body 115 surrounding the piston 124. The piston 124 is capable of moving within the body 115 between opposite ends 123, 125 within the body 115 of the piston assembly 120, as further described below. In one embodiment, the surrounding body 115 is laterally keyed or otherwise slotted 121 between the first end 123 and the second end 125. The piston 124 defines a key or other raised structure within the slot 121 to prevent rotation of the piston 124. A friction mechanism 122 is coupled to the piston 124 at the second end 125. The piston 124 is releasably coupled to the input shaft 134 of the input drive assembly 130 via the friction mechanism 122. Figure 1A and Figure 2A respectively depict the piston assembly 120 separated from the input drive assembly 130. Figure 1B and Figure 2B respectively depict the piston assembly 120 engaged with the input drive assembly 130. Figures 1A-1B and Figures 2A-2B together depict the piston assembly 120 releasably engaged with the input drive assembly 130, as further described herein.

[0039] In one embodiment, as depicted with respect to Figures 1A-1B the friction mechanism 122 defines a clutch mechanism or friction disk that is configured to engage the input drive assembly 130 when the piston 124 moves onto the input driver 124. The friction mechanism 122 defining the friction disk includes a minimum travel or zone 135 between the friction mechanism 122 at the second end 125 and the input drive assembly 130 to improve the fail-safe position and response time, as further described below.

[0040] In another embodiment, for example with respect to Figures 2A-2B as depicted, the friction mechanism 122 defines a concave tooth or serrated geometry at the input drive assembly 130 and the piston 124. The serrated geometry of the friction mechanism 122 can provide an improved mechanical engagement force for prohibiting unwanted rotation of the output shaft 110. Relative to the serrated geometry( Figures 2A-2B ), the friction mechanism 122 that defines the friction disk( Figures 1A-1B ) can provide an improved response time such that the minimum stroke or area 135 between the second end 125 of the piston 124 is less than the tooth height of the serrated geometry. As further described herein, the piston 124 can be displaced toward the second end 125 to contact the input drive assembly 130. The input drive assembly 130 can only rotate within the range allowed by the friction mechanism 122 such as the serrated geometry (e.g., corresponding to Figures 2A-2B the tooth geometry depicted in

[0041] Referring to Figures 1A-1B and Figures 2A-2B , various embodiments of the actuator assembly 90 include a spring 126 that is coupled at the first end 123 of the piston 124 and the body 115. The spring 126 is disposed within the body 115 of the piston assembly 120 so as to act against the body 115 and the first end 123 of the piston 124. An opening 128 is defined to be in fluid communication with the region 135 within the body 115 through the body 115. The opening 128 is further defined at the second end 125, between the piston 124 and the input drive assembly 130, to receive and discharge the fluid 153 within the region 135, as further described below.

[0042] Referring to Figures 2A-2B , a schematic embodiment of the actuator assembly 90 is depicted further including a control valve assembly 140. The control valve assembly 140 includes a first input pressure opening 150 that is configured to receive a liquid or gas power fluid, schematically illustrated via arrow 151. The power fluid 151 can generally include a hydraulic or pneumatic high-pressure source, for example, in fluid communication with the input drive assembly 130 to rotate or displace the output shaft 110.

[0043] During the faultless operation of the actuator assembly 90 or the surrounding device 10, an electrical signal is applied to the control valve assembly 140 to disable, for example, the pressure or force from the power fluid 151 by closing the input opening 150 at the control valve assembly 140, through which the power fluid 151 can enter the control valve assembly 140. The control valve assembly 140 is actuated so that at least a portion of the power fluid schematically shown by arrow 153 can flow from the opening 148 at the control valve assembly 140 into the region 135 within the body 115 between the piston 124 at the second end 125 and the input drive assembly 130, as depicted, for example, with respect to Figure 2A The spring 126 provides a compressive force towards the input drive assembly 130, and the power fluid 153 provides a reaction force, thereby preventing the piston 124 from being coupled to the input drive assembly 130 at the friction mechanism 122. In other words, the pressures on the opposite sides 123, 125 of the piston 124 are substantially equal and opposite during faultless operation. The power fluid 153 allows the piston 124 to shift away from the input drive assembly 130 so that the input drive assembly 130 and the output shaft 110 coupled thereto can move freely.

[0044] Now referring to Figure 2B , after the electrical signal to the control valve assembly 140 is lost, the control valve assembly 140 is no longer energized and, thus, allows the power fluid 151 input to the control valve assembly 140 to shift the control valve assembly 140 to interrupt the pressurized output of the power fluid 153 from the control valve assembly 140 and to allow the input power fluid 151 from the control valve 140 to enter the plenum 136 (schematically shown by arrow 152) to reduce the region 135 at the second end 125 of the body 115. The decompressed fluid 153 returns from the body 115 to the control valve assembly 140 by the force exerted by the power fluid 152 in the spring 126 and the plenum 136 towards the input drive assembly 130 and reduces the region 135 between the piston 124 and the input drive assembly 130. When the friction mechanism 122 establishes contact between the piston 124 and the input drive assembly 130, the region 135 closes, thereby prohibiting the undesired rotation or additional rotation of the output shaft 110 after a failure of the control system or other input power or actuation source.

[0045] Various embodiments of piston 124 may define a half - area servo piston that, when substantially equal pressures are applied to opposite ends 123, 125 or to pressurizing chamber 136 and area 135, enables movement away from input drive assembly 130 (e.g., toward first end 123), thereby allowing free movement of input drive assembly 130. For example, the half - area servo piston may be defined as being smaller relative to input drive assembly 130. In other embodiments, piston 124 may define a non - half area servo piston that applies a desired load to either end 123, 125 or both ends 123, 125 of piston 124.

[0046] It should be understood that features shown or described as part of Figures 1A-1B may be used in conjunction with features shown as part of Figures 2A-2B or further used with respect to the Figure 3 devices to be further described below. For example, the control valve 140 depicted with respect to Figures 2A-2B may be used and operated with respect to the Figures 1A-1B illustrated and described embodiments. As another example, one or more controllers configured to provide signals to and / or receive signals from actuator assembly 90 and / or further including control valve 140 may be configured as part of the Figure 3 devices to be further described below.

[0047] Figure 3 is a schematic partial cross - sectional side view of an exemplary device 10 in which actuator assembly 90 may be incorporated. Although generally depicted herein as defining a turbofan configuration of a gas turbine engine, the device 10 shown and described herein may define any system including, for example, the actuation systems described herein. Additionally or alternatively, although depicted as a gas turbine engine defining a turbofan, device 10 may generally define a turbine, or more specifically, a turbojet engine, a turboprop engine or a turboshaft gas turbine engine configuration, including those configurations for industrial or marine use, or a steam turbine engine. As Figure 3 shown, device 10 has a longitudinal or axial centerline axis 12 extending therethrough for reference purposes. An upstream end 99 and a downstream end 98 are each defined for reference purposes and generally represent the direction in which air enters device 10 (i.e., upstream end 99) and the direction in which air leaves device 10 (i.e., downstream end 98). Generally, device 10 may include a fan assembly 14 and a core engine 16 disposed downstream of fan assembly 14.

[0048] The core engine 16 may generally include a substantially tubular outer casing 18 that defines an annular inlet 20. The outer casing 18 surrounds or at least partially forms in a series flow relationship: a compressor section 21 having a booster or low pressure (LP) compressor 22, a high pressure (HP) compressor 24, and / or one or more intermediate pressure (IP) compressors (not shown) aerodynamically disposed between the LP compressor 22 and the HP compressor 24; a combustion section 26; a turbine section 31 including a high pressure (HP) turbine 28, a low pressure (LP) turbine 30, and / or one or more intermediate pressure (IP) turbines (not shown) aerodynamically disposed between the HP turbine 28 and the LP turbine 30; and an exhaust nozzle section 32. A high pressure (HP) rotor shaft 34 drivingly connects the HP turbine 28 to the HP compressor 24. A low pressure (LP) rotor shaft 36 drivingly connects the LP turbine 30 to the LP compressor 22. In other embodiments, an IP rotor shaft drivingly connects an IP turbine to an IP compressor (not shown). The LP rotor shaft 36 may also or alternatively be connected to the fan shaft 38 of the fan assembly 14. In a particular embodiment, for example Figure 3 as shown, the LP shaft 36 may be connected to the fan shaft 38 via a power or reduction gear assembly 40, such as in an indirect drive or gear drive configuration.

[0049] The combination of the compressors 22, 24, the turbines 28, 30, and the shafts 34, 36, 38 each define a rotor assembly of the device 10. For example, in various embodiments, the LP turbine 30, the LP shaft 36, the fan assembly 14, and / or the LP compressor 22 together define a low pressure (LP) rotor assembly as the rotor assembly. The rotor assembly may further include a fan rotor 38 coupled to the fan assembly 14 and the LP shaft 36 via a gear assembly 40. As another example, the HP turbine 28, the HP shaft 34, and the HP compressor 24 may together define a high pressure (HP) rotor assembly as the rotor assembly. It should further be understood that a rotor assembly may be defined by the combination of an IP compressor, an IP turbine, and an IP shaft aerodynamically disposed between the LP rotor assembly and the HP rotor assembly.

[0050] As Figure 3 shown, the fan assembly 14 includes a plurality of fan blades 42 that are coupled to the fan shaft 38 and extend radially outwardly from the fan shaft 38. An annular fan casing or nacelle 44 circumferentially surrounds the fan assembly 14 and / or at least a portion of the core engine 16. Those skilled in the art will appreciate that the nacelle 44 may be configured to be supported relative to the core engine 16 by a plurality of circumferentially spaced outlet guide vanes or struts 46. Additionally, at least a portion of the nacelle 44 may extend over an outer portion of the core engine 16 so as to define a bypass air flow passage 48 therebetween.

[0051] During operation of the device 10, a quantity of air, schematically shown by arrow 74, enters the device 10 through the nacelle 44 and / or the associated inlet 76 of the fan assembly 14. As the air 74 passes through the fan blades 42, a portion of the air, schematically shown by arrow 78, is directed or guided into the bypass air flow passage 48, and substantially most of the propulsive force is generated through the bypass air flow passage 48, while another portion of the air, schematically shown by arrow 80, is directed or guided into the LP compressor 22. As the air 80 flows towards the combustion section 26 through the LP compressor 22 and the HP compressor 24, the air 80 is gradually compressed.

[0052] Still referring Figure 3 , the combustion gas 86 generated in the combustion section 26 flows towards the HP turbine 28 of the turbine section 31, thereby causing the HP shaft 34 to rotate, thus supporting the operation of the HP compressor 24. As Figure 3 shown, the combustion gas 86 is then directed to the LP turbine 30, thereby causing the LP shaft 36 to rotate, thus supporting the operation of the LP compressor 22 and the rotation of the fan shaft 38. Then, the combustion gas 86 is discharged through the jet exhaust nozzle section 32 of the core engine 16 to provide propulsive force.

[0053] As the operation of the device 10 transitions from stationary or zero RPM to start-up and ignition, minimum steady-state operation (i.e., minimum steady-state air and fuel flowing through the core engine 16 to maintain approximately zero acceleration), maximum steady-state operation (i.e., maximum steady-state air and fuel flowing through the core engine 16 to maintain approximately zero acceleration), or one or more intermediate steady-state operation states therebetween, the actuator assembly 90 can be incorporated at the variable vane assembly 100 at the device 10 to adjust the angle of attack or the angle of rotation of axially separated vane stages (e.g., vanes at one or more of the fan section 14, compressor section 21, turbine section 31, etc.).

[0054] Returning to reference Figure 3 , the controller 210 can generally correspond to any suitable processor-based device, including one or more computing devices. For example, Figure 3 an embodiment showing suitable components that can be included within the controller 210 is shown. As Figure 3 shown, the controller 210 can include a processor 212 and an associated memory 214, which are configured to perform various computer-implemented functions. In various embodiments, the controller 210 can be configured to operate the actuator assembly 90 so as to provide a signal to the control valve 140, commanding the supply of power fluid to the input drive assembly 130 or adjusting the pressure of the power fluid.

[0055] As used herein, the term "processor" refers not only to integrated circuits known in the art as being included in a computer, but also to controllers, microcontrollers, microcomputers, programmable logic controllers (PLCs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), and other programmable circuits. Additionally, the memory 214 may generally include one or more storage elements, including but not limited to computer-readable media (e.g., random access memory (RAM)), computer-readable non-volatile media (e.g., flash memory), compact disc read-only memory (CD-ROM), magneto-optical disc (MOD), digital versatile disc (DVD), and / or other suitable storage elements or combinations thereof. In various embodiments, the controller 210 may define one or more of a full authority digital engine controller (FADEC), a propeller control unit (PCU), an engine control unit (ECU), or an electronic engine control (EEC).

[0056] As shown, the controller 210 may include control logic 216 stored in the memory 214. The control logic 216 may include instructions that, when executed by one or more processors 212, cause the one or more processors 212 to perform operations such as rotating, extending, or retracting, or otherwise shifting the actuator assembly 90.

[0057] Additionally, as Figure 3 shown, the controller 210 may further include a communication interface module 230. In various embodiments, the communication interface module 230 may include associated electronic circuitry for sending and receiving data. Thus, the communication interface module 230 of the controller 210 may be used to receive data from the actuator assembly 90 or from a position sensor of an attached blade assembly.

[0058] Additionally, the communication interface module 230 may also be used to communicate with the actuator assembly 90 or any other suitable component of the device 10 in order to receive data from or send commands to any number of valves, blade assemblies, hydraulic or pneumatic systems providing motive fluid, rotor assemblies, ports, etc., to control speed, pressure, or flow at the device 10 including the control valve assembly 140 or at the actuator assembly 90.

[0059] It should be understood that the communication interface module 230 may be any combination of suitable wired and / or wireless communication interfaces and may thus be communicatively coupled to one or more components of the actuator assembly 90 via wired and / or wireless connections. In this way, the controller 210 may operate, adjust, or regulate the operation of the actuator assembly 90, and / or acquire or transmit signals via the actuator assembly 90 including the control valve 140.

[0060] This written description uses examples to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the invention, including making and using any device or system, and performing any combination of methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. If these other examples include structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that have no substantial difference from the literal language of the claims, then these other examples are intended to be within the scope of the claims.

[0061] Further aspects of the invention are provided by the subject matter of the following clauses:

[0062] 1. An actuator assembly, the actuator assembly comprising: an output shaft; an input drive assembly; and a piston assembly, the piston assembly including a body that surrounds a piston, the piston being movable within the body, wherein the body defines a first end and a second end opposite the first end, the piston being movable within the body between the first end and the second end, and further wherein the piston assembly includes a spring disposed at the first end, between the body and the piston, and wherein the piston assembly includes a friction mechanism disposed at the second end of the piston opposite the first end, and wherein an adjustable region is defined within the body, between the second end of the piston and the input drive assembly.

[0063] 2. The actuator assembly according to any preceding clause, wherein the body defines a groove that extends laterally between the first end and the second end, and wherein the piston is at least partially disposed within the groove to prevent rotation of the piston.

[0064] 3. The actuator assembly according to any preceding clause, wherein the friction mechanism includes a friction disk configured to engage the piston and the input drive assembly together.

[0065] 4. The actuator assembly according to any preceding clause, wherein the friction mechanism includes a serrated geometry at the servo piston and the input shaft, the serrated geometry being configured to statically couple the servo piston and the input drive assembly together.

[0066] 5. The actuator assembly according to any preceding clause, wherein the body defines an opening therethrough that is in fluid communication with the region between the piston and the input drive assembly.

[0067] 6. The actuator assembly according to any preceding item further includes: a control valve assembly configured to supply and discharge power fluid to and from the area between the piston and the input drive assembly.

[0068] 7. The actuator assembly according to any preceding item, wherein the control valve assembly is configured to supply power fluid to the area between the piston and the input drive assembly, equal to and opposite to the force exerted by the spring toward the input drive assembly.

[0069] 8. The actuator assembly according to any preceding item, wherein the control valve assembly is configured to discharge the power fluid from the area between the piston and the input drive assembly after loss of signal to the control valve assembly.

[0070] 9. The actuator assembly according to any preceding item, wherein the piston assembly is configured to engage with the input drive assembly via the friction mechanism after the power fluid is discharged from the area between the piston and the input drive assembly.

[0071] 10. The actuator assembly according to any preceding item, wherein the piston defines one or more of a stop ring or a servo controller piston.

[0072] 11. A device for fail-safe actuation, the device including: an actuator assembly, wherein the actuator assembly includes an output shaft, an input drive assembly, and a piston assembly, the piston assembly including a body surrounding the piston, the piston being movable within the body, wherein the body defines a first end and a second end opposite the first end, the piston being movable within the body between the first end and the second end, and further wherein the piston assembly includes a spring disposed at the first end, between the body and the piston, and wherein the piston assembly includes a friction mechanism disposed at the second end of the piston opposite the first end, and wherein an adjustable area is defined within the body, between the second end of the piston and the input drive assembly, and wherein the actuator assembly further includes a control valve assembly configured to supply and discharge power fluid to and from the area between the piston and the input drive assembly; and a controller configured to provide a signal to the control valve of the actuator assembly.

[0073] 12. According to the device of any preceding item, wherein the controller provides the signal to the control valve assembly to close the input opening at the control valve assembly, and closing the input opening holds the power fluid at the area between the piston and the input drive assembly, equal and opposite to the force exerted by the spring towards the input drive assembly.

[0074] 13. According to the device of any preceding item, wherein the control valve assembly is configured to discharge the power fluid from the area between the piston and the input drive assembly after the loss of the signal from the controller to the control valve assembly.

[0075] 14. According to the device of any preceding item, wherein the control valve assembly is configured to close the input opening at the control valve assembly to prohibit the power fluid from the area between the piston and the input drive assembly.

[0076] 15. According to the device of any preceding item, wherein the piston assembly is configured to engage with the input drive assembly via the friction mechanism after the power fluid is discharged from the area between the piston and the input drive assembly.

[0077] 16. According to the device of any preceding item, wherein the body defines a groove that extends laterally between the first end and the second end, and wherein the piston is at least partially disposed in the groove to prevent the piston from rotating.

[0078] 17. According to the device of any preceding item, wherein the friction mechanism includes a friction disk configured to engage the piston and the input drive assembly together.

[0079] 18. According to the device of any preceding item, wherein the friction mechanism includes a serrated geometry at the servo piston and the input shaft, and the serrated geometry is configured to statically couple the servo piston and the input drive assembly together.

[0080] 19. According to the device of any preceding item, wherein the body defines an opening therethrough that is in fluid communication with the area between the piston and the input drive assembly.

[0081] 20. According to the device of any preceding item, wherein the piston defines one or more of a stop ring or a servo controller piston.

Claims

1. An actuator assembly, characterized in that, the actuator assembly comprises: an output shaft; an input drive assembly; and a piston assembly, the piston assembly comprising a body that surrounds a piston, the piston being movable within the body, wherein the body defines a first end and a second end opposite the first end, the piston being movable within the body between the first end and the second end, and further wherein the piston assembly comprises a spring that is disposed at the first end, between the body and the piston, and wherein the piston assembly comprises a friction mechanism that is disposed at the second end of the piston opposite the first end, and wherein an adjustable region is defined within the body, between the second end of the piston and the input drive assembly, wherein the friction mechanism comprises a friction disk configured to engage the piston and the input drive assembly together during a fault operation.

2. The actuator assembly according to claim 1, characterized in that, wherein the body defines a groove that extends laterally between the first end and the second end, and wherein the piston is at least partially disposed within the groove to prevent rotation of the piston.

3. The actuator assembly according to claim 1, characterized in that, wherein the body defines an opening therethrough that is in fluid communication with the region between the piston and the input drive assembly.

4. The actuator assembly according to claim 1, characterized in that, further comprising: a control valve assembly configured to supply and discharge a power fluid to and from the region between the piston and the input drive assembly.

5. The actuator assembly according to claim 4, characterized in that, wherein the control valve assembly is configured to supply the power fluid to the region between the piston and the input drive assembly, equal and opposite to the force exerted by the spring towards the input drive assembly.

6. The actuator assembly according to claim 4, characterized in that, wherein the control valve assembly is configured to discharge the power fluid from the region between the piston and the input drive assembly after loss of a signal to the control valve assembly.

7. The actuator assembly according to claim 6, characterized in that, wherein the piston assembly is configured to engage the input drive assembly via the friction mechanism after the power fluid is discharged from the region between the piston and the input drive assembly.

8. The actuator assembly according to claim 1, characterized in that, wherein the piston defines one or more of a stop ring or a servo controller piston.

9. A device for fail-safe actuation, characterized in that, the device comprises: An actuator assembly, wherein the actuator assembly includes an output shaft, an input drive assembly, and a piston assembly, the piston assembly including a body that surrounds a piston that is movable within the body, wherein the body defines a first end and a second end opposite the first end, the piston being movable within the body between the first end and the second end, and further wherein the piston assembly includes a spring disposed at the first end, between the body and the piston, and wherein the piston assembly includes a friction mechanism disposed at the second end of the piston opposite the first end, and wherein an adjustable region is defined within the body, between the second end of the piston and the input drive assembly, wherein the friction mechanism includes a friction disk configured to engage the piston and the input drive assembly together during a fault operation, and wherein the actuator assembly further includes a control valve assembly configured to supply and discharge a power fluid to and from the region between the piston and the input drive assembly; and A controller configured to provide a signal to the control valve of the actuator assembly.

10. The apparatus according to claim 9, wherein, the controller provides the signal to the control valve assembly to close an input opening at the control valve assembly, closing the input opening maintaining the power fluid at the region between the piston and the input drive assembly, equal and opposite to the force exerted by the spring toward the input drive assembly.

11. The apparatus according to claim 9, wherein, the control valve assembly is configured to discharge the power fluid from the region between the piston and the input drive assembly after loss of the signal from the controller to the control valve assembly.

12. The apparatus according to claim 11, wherein, the control valve assembly is configured to close an input opening at the control valve assembly to prohibit the power fluid from the region between the piston and the input drive assembly.

13. The apparatus according to claim 11, wherein, the piston assembly is configured to engage the input drive assembly via the friction mechanism after the power fluid is discharged from the region between the piston and the input drive assembly.

14. The apparatus according to claim 9, wherein, the body defines a groove that extends laterally between the first end and the second end, and wherein the piston is at least partially disposed within the groove to prevent rotation of the piston.

15. The apparatus according to claim 9, wherein, the body defines an opening therethrough that is in fluid communication with the region between the piston and the input drive assembly.

16. The apparatus according to claim 9, wherein, Wherein the piston defines one or more of a stop ring or a servo controller piston.

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