Rotary actuator

Abstract

The invention relates to a rotary actuator. A rotary actuator includes a manifold block and a rotor assembly including a rotor shaft and a plurality of arcuate pistons attached to the rotor shaft, each arcuate piston curved at a set radial distance from the rotor shaft, and each piston attached to the rotor shaft via a crank arm. A pressure chamber assembly coupled to the manifold block defines a plurality of piston pressure chambers that receive and at least partially surround each arcuate piston, including a plurality of gland seals disposed adjacent an inlet of each piston pressure chamber to create a seal between an inner surface of the pressure chambers and an arcuate piston outer surface. Each gland seal includes an inner seal that engages a piston surface of the arcuate piston and a plurality of outer seals that engage an inner surface of the piston pressure chamber, thereby forming a hydraulic seal.

Description

[0001] This application is a divisional application of Chinese patent application 2021101908926 entitled "Rotary Actuator", filed on February 20, 2021. Technical Field

[0002] This disclosure relates to rotary actuators. More specifically, this disclosure relates to rotary actuators for controllably positioning flight control surfaces of an aircraft. Background Technology

[0003] The pilot controls the aircraft in flight by manipulating its flight control surfaces, which include primary flight control surfaces such as ailerons, elevators, and rudders, as well as secondary flight control surfaces such as spoilers, flaps, slats, and air brakes. Actuation of these flight control surfaces allows the pilot to control the aircraft's pitch, yaw, roll, and climb, as well as other flight characteristics.

[0004] Movement of flight control surfaces is typically achieved via one or more linear actuators, which are usually positioned approximately perpendicular to the pivot axis of the attached control surface and connected to the control surface via articulated links. This positioning usually requires mounting the linear actuator within the rudder, elevator, or wing.

[0005] In pursuit of greater efficiency and enhanced flight performance, aircraft wings have become increasingly thinner over time. In particular, the distance between the top and bottom of the outer mold line (OML) at the typical control surface pivot axis has become significantly smaller. When conventional piston-like linear actuators are installed within such thin wings, the actuators or articulated links can protrude partially beyond the wing surface, increasing drag and reducing fuel efficiency, even when surrounded by a dome or bubble shield.

[0006] Specifically, the ailerons are positioned along the trailing edge of the wing, where only minimal internal space is available for the coupled actuators. Therefore, for such applications, a small-footprint rotary hydraulic actuator is required. Unfortunately, previous rotary hydraulic actuators could not operate continuously without hydraulic leaks, potentially affecting the precise positioning of the ailerons and creating numerous maintenance problems. Summary of the Invention

[0007] This disclosure provides a rotary actuator, including a control surface actuator system for the rotary actuator, and a method for actuating an aircraft control surface using the rotary actuator.

[0008] In some examples, this disclosure relates to a rotary actuator including a manifold block and a first rotor assembly mounted to the manifold block. The first rotor assembly further includes a first rotor shaft extending into the manifold block; and a plurality of bow-shaped pistons attached to the rotor shaft, each bow-shaped piston being bent at a predetermined radial distance from the axis of rotation of the rotor shaft, and each piston being attached to the rotor shaft via a crank arm; a first pressure chamber assembly coupled to the manifold block, the first pressure chamber defining a plurality of piston pressure chambers configured to receive and at least partially surround each bow-shaped piston; and a plurality of gland seals disposed adjacent to the inlet of each piston pressure chamber and creating a seal between the inner surface of the piston pressure chamber and the outer surface of the bow-shaped piston inserted therein, wherein each gland seal includes an inner seal configured to engage the surface of the bow-shaped piston and a plurality of outer seals configured to engage the inner surface of the piston pressure chamber, such that a hydraulic seal is formed between each piston pressure chamber and the bow-shaped piston inserted therein. The first rotor assembly is configured such that delivering hydraulic fluid to a plurality of piston pressure chambers causes an arc-shaped piston disposed in each piston pressure chamber to translate about a set radial distance about the axis of rotation of the first rotor shaft, thereby causing the first rotor shaft to rotate.

[0009] In some examples, this disclosure relates to a control surface actuator system comprising an aircraft control surface, a rotary actuator coupled to the control surface such that operation of the rotary actuator actuates movement of the control surface. The rotary actuator may include a manifold block and first and second rotor assemblies mounted along an axis of rotation to opposite sides of the manifold block. Each of the first and second rotor assemblies further includes a rotor shaft extending along the axis of rotation into the manifold block; a plurality of bow-shaped pistons attached to the rotor shaft, each piston bending along a defined radial distance from the axis of rotation of the rotor shaft and each piston being attached to the rotor shaft via an intermediate crank arm; a pressure chamber assembly coupled to the manifold block, the pressure chamber defining a plurality of piston pressure chambers configured to receive and at least partially surround the plurality of bow-shaped pistons; and a plurality of gland seals disposed adjacent to the inlet of each piston pressure chamber and creating a seal between the inner surface of the piston pressure chamber and the bow-shaped piston disposed therein. Each gland seal includes an inner seal configured to engage the bow-shaped piston and a plurality of outer seals configured to engage the inner surface of the piston pressure chamber, such that a hydraulic seal is formed between each piston pressure chamber and the bow-shaped piston inserted therein. Each rotor assembly is configured such that delivering hydraulic fluid to multiple piston pressure chambers causes the bow-shaped pistons disposed within each piston pressure chamber to translate about the axis of rotation, thereby increasing the volume of the piston pressure chambers and thus rotating the coupled rotor shaft.

[0010] In some examples, this disclosure relates to a method of actuating aircraft control surfaces. The method may include providing a rotary actuator, wherein the rotary actuator includes a manifold block and a first rotor assembly mounted to the manifold block. The first rotor assembly may include a first rotor shaft extending into the manifold block; a plurality of bow-shaped pistons attached to the rotor shaft, each piston being bent along a defined radial distance from the axis of rotation of the rotor shaft, and each piston being attached to the rotor shaft via an intermediate crank arm; a first pressure chamber assembly coupled to the manifold block, the first pressure chamber defining a plurality of piston pressure chambers configured to receive and at least partially surround the plurality of bow-shaped pistons; wherein the manifold block defines a plurality of internal channels for delivering hydraulic fluid to the piston pressure chambers; and a plurality of gland seals disposed adjacent to the inlet of each piston pressure chamber and creating a seal between the inner surface of the piston pressure chamber and the bow-shaped piston disposed therein. Each gland seal may include an inner seal configured to engage a surface of the bow-shaped piston and a plurality of outer seals configured to engage the inner surface of the piston pressure chamber, such that a hydraulic seal is formed between each piston pressure chamber and the bow-shaped piston inserted therein. The first rotor assembly is configured such that supplying hydraulic fluid to a plurality of piston pressure chambers via a plurality of internal channels of a manifold causes an arcuate piston disposed in each piston pressure chamber to translate about a rotational axis of the first rotor shaft, thereby rotating the first rotor shaft. The inner end of the first rotor shaft extends into a recess formed in the manifold, wherein an output lug engages the inner end of the first rotor shaft to an aircraft control surface. The method may further include supplying pressurized hydraulic fluid to a first pressure chamber assembly via the internal channels of the manifold to increase the hydraulic fluid pressure in the piston pressure chambers of the first pressure chamber assembly; rotating the first rotor shaft by pushing the arcuate piston disposed in the piston pressure chambers of the first pressure chamber assembly to translate about a rotational axis of the first rotor shaft due to the increased hydraulic fluid pressure in the piston pressure chambers; moving the output lug engaged to the inner end of the first rotor shaft by rotating the first rotor shaft; and actuating the aircraft control surface by moving the output lug.

[0011] Features, functions, and advantages may be implemented independently in the various examples of this disclosure or may be combined in other examples, further details of which may be understood with reference to the following description and figures. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of an aircraft that identifies selected control surfaces.

[0013] Figure 2 This is a schematic cross-sectional view showing a conventional linear actuator attached to a control surface at the trailing edge of the wing.

[0014] Figure 3 An exemplary rotary actuator according to this disclosure is depicted.

[0015] Figure 4 Depicting Figure 3 An exemplary rotary actuator.

[0016] Figure 5 yes Figure 3 A cross-sectional view of the manifold block of the rotary actuator.

[0017] Figure 6 Depicting Figure 3 The exemplary rotary actuator includes a rotor shaft, crank arm, and bow-shaped piston in the first rotor assembly.

[0018] Figure 7 Depicting Figure 3 The pressure chamber assembly of the first rotor assembly of an exemplary rotary actuator.

[0019] Figure 8 Depicted in a plane orthogonal to the axis of rotation of the rotor shaft Figure 3 A cross-sectional view of the first rotor assembly of the rotary actuator.

[0020] Figure 9 Depicting Figure 3 A cross-sectional view of the piston pressure chamber of the first rotor assembly of the rotary actuator.

[0021] Figure 10 yes Figure 3 A cross-sectional view of the gland seal of the piston pressure chamber of a rotary actuator.

[0022] Figure 11 Depicting Figure 3 The manifold block of the rotary actuator.

[0023] Figure 12 Depicting Figure 3 A rotary actuator comprising first and second rotary assemblies, omitting the first actuator housing and the second actuator housing.

[0024] Figure 13 This is a schematic cross-sectional view showing a control surface actuator system, which includes a rotary actuator of this disclosure coupled to a control surface at the trailing edge of the wing.

[0025] Figure 14 This is a flowchart depicting an illustrative method for actuating aircraft control surfaces according to the present disclosure. Detailed Implementation

[0026] Various aspects and examples of rotary actuators, control surface actuation systems, and methods for actuating aircraft control surfaces will be described below and illustrated in the relevant figures. Unless otherwise stated, rotary actuators, systems, and methods, their various steps, and variations may, but are not required to, include at least one of the structures, components, functions, and / or variations described, shown, and / or incorporated herein. Furthermore, unless expressly excluded, the processing steps, structures, components, functions, and / or variations described, shown, and / or incorporated herein may be included in other similar apparatuses and methods, and are interchangeable among the disclosed examples. The following description of various examples is illustrative in nature only and is in no way intended to limit the examples, their application, or use. Additionally, the advantages offered by the examples described below are illustrative in nature, and not all examples offer the same advantages or advantages of the same degree.

[0027] This specific implementation comprises the following sections in the following order: (1) Definitions; (2) Overview; (3) Examples, Components and Alternatives; (4) Illustrative Combinations and Additional Examples; (5) Advantages, Features and Benefits; and (6) Conclusions.

[0028] definition Unless otherwise specified, the following definitions apply here.

[0029] "Substantially" means that it primarily conforms to the specific dimensions, range, shape, concept, or other aspects modified by the term, such that the features or components do not need to be perfectly identical, as long as they are suitable for their intended purpose or function. For example, an object that is "substantially cylindrical" means that the object resembles a cylinder, but may have one or more deviations from a real cylinder.

[0030] The terms “include,” “contain,” and “have” (and their variations) are used interchangeably to mean including but not limited to, and are open-ended terms not intended to exclude additional unreferenced elements or method steps.

[0031] Terms such as “first,” “second,” and “third” are used to distinguish or identify various members in a group, etc., in the order in which they are introduced in a particular context, and are not intended to indicate an order or numerical restriction, or a fixed identifier for group members.

[0032] "Connection" means a relationship in which the performance of one object affects the performance of another, which may include a permanent or releasable connection, either directly or indirectly through an intermediate component, and is not necessarily limited to (one or more) physical connections.

[0033] Overview Figure 1The image shows an aircraft 10, including the identification of selected primary and secondary flight control surfaces. The aircraft flight control surfaces may include a rudder 12 on the vertical stabilizer 14, an elevator 16 on the horizontal stabilizer 18, ailerons 20 and spoilers 22 on the wing 24, and slats 26 and flaps 28 also on the wing 24.

[0034] Figure 2 This is a partial cross-section of the aileron control surface 20, which is integrated with the wing 24, and where the aileron 20 is coupled to a conventional linear actuator 30. As shown, actuation of the aileron 20 requires an extension of the linear actuator 30. Due to the relatively thin cross-section of the wing 24, even in the intermediate position (A), the linear actuator 30 extends beyond the envelope of the wing 24, and then protrudes further during actuation (B). Even when fully retracted, the actuator coupling 31 between the linear actuator 30 and the aileron 20 extends beyond the skin of the wing 24 (C).

[0035] exist Figure 3 and Figure 4 An exemplary rotary actuator 32 is shown, which has been configured to minimize the space requirements of the control surface actuator. The rotary actuator 32 includes a manifold block 34, a first rotor assembly 36, and a second rotor assembly 38. The first and second rotor assemblies are mounted to the manifold block 34 on opposite sides, respectively. Figure 3 Specifically, the manifold block 34 includes a mounting bracket 40 for attaching the rotary actuator 32 to and within the aircraft 10 via the manifold block 34. The rotary actuator 32 also includes an output lug 42 extending from a recess 44 formed in the manifold block 34, such as... Figure 4 As shown. Although the output lug 42 extends from the groove 44 in the manifold block 34, the output lug 42 is not attached to the manifold block 34, but is directly connected to the inner end 45 of the first rotor shaft 46 extending from the first rotor assembly 36, and the inner end 47 of the second rotor shaft 48 extending from the second rotor assembly 38, as shown. Figure 5 As shown. The output lug 42 is also configured to be connected to the actuator arm, which in turn is connected to the control surface, such that operation of the rotary actuator 32 will actuate the movement of the control surface.

[0036] The manifold block 34 may additionally include a hydraulic interface 50, which may include multiple connection ports to facilitate connection of the hydraulic system of the rotary actuator 32 to the hydraulic system of the aircraft 10.

[0037] The first rotor assembly 36 and the second rotor assembly 38 may each include a first actuator housing 51 and a second actuator housing 52. The actuator housings are hermetically coupled to a manifold block 34 on the opposite side of the manifold block, and each actuator housing surrounds the remaining components of the corresponding first and second rotor assemblies, as will be discussed below specifically with respect to the components of the first rotor assembly 36.

[0038] like Figure 6 As shown, the first rotor assembly 36 may include a first rotor shaft 46 extending the length of the first rotor assembly 36 and entering into the manifold block 34, defining a rotation axis 56 within the first actuator housing 51. A plurality of crank arms 58 may be attached to the first rotor shaft 46, wherein each crank arm connects the first rotor shaft 46 to a bow-shaped piston 60. Each bow-shaped piston 60 is shaped to extend along a curve 61 at a predetermined radial distance 62 from the rotation axis 56 of the first rotor shaft 46, wherein the predetermined radial distance 62 for each bow-shaped piston 60 is identical (e.g., ...). Figure 8 (As shown).

[0039] Each of the bow-shaped pistons 60 may be configured to have an elongated cross-section with rounded edges and a rounded distal surface opposite to the end of the bow-shaped piston 60 attached to the crank arm 58. The specific shape of the bow-shaped pistons is not critical, as long as they are precisely and smoothly machined to tight tolerances and they follow a curve 61 with a defined radial distance 62. For example, without departing from the scope and spirit of this disclosure, the bow-shaped piston 60 may have a circular cross-section (in the form of a bow-shaped rod), or the bow-shaped piston 60 may have a square or rectangular cross-section.

[0040] like Figure 7 As shown, the first rotor assembly 36 may include one or more first pressure chamber assemblies 64 coupled to and extending from the manifold block 34. Each first pressure chamber assembly 64 defines a plurality of piston pressure chambers 66, wherein each piston pressure chamber 66 is configured to receive and at least partially surround the bow-shaped piston 60, as... Figure 8 As shown. The first rotor assembly 36 can be configured to include a piston pressure chamber 66 corresponding to each bow-shaped piston 60 in the first rotor assembly 36.

[0041] The bow-shaped piston 60 and the piston pressure chamber 66 can be manufactured with precise tolerances such that each bow-shaped piston 60 moves freely within its corresponding piston pressure chamber 66 along a predetermined radial distance 62 from the axis of rotation 56, wherein there is minimal or no contact between the outer surface 68 of the bow-shaped piston 60 and the inner surface 70 of the piston pressure chamber 66. In addition to eliminating destructive wear on the components of the first rotor assembly 36, such precise tolerances can also help improve the hydraulic operation of the resulting rotary actuator.

[0042] Although the bow-shaped piston 60 and the piston pressure chamber 66 do not actually make physical contact when the bow-shaped piston 60 moves within the piston pressure chamber, the piston pressure chamber is hydraulically sealed by inserting a gland seal assembly 72 between the outer surface 68 of the bow-shaped piston 60 and the inner surface 70 of the piston pressure chamber 66. The components of the gland seal 68 are... Figure 9 and 10 It is shown in more detail below.

[0043] Each gland seal assembly 72 is disposed adjacent to the inlet 74 of the piston pressure chamber 66 such that, when at least partially inserted into its corresponding piston pressure chamber 66, the gland seal assembly 72 can create a hydraulic seal between the inner surface 70 of the piston pressure chamber 66 and the outer surface 68 of the arcuate piston 60. Each gland seal assembly 72 may include a gland 76 located within a gland orifice 78 formed in the inner surface 70 of the piston pressure chamber 66. The gland orifice 78 is generally formed around the circumference of the inner surface 70 such that, when the gland seal assembly 72 is positioned within the gland orifice 78, and when the piston 60 is at least partially inserted into the piston pressure chamber 66, the gland seal assembly 72 surrounds the arcuate piston 60.

[0044] The cap 76 can be held within the cap hole 78 by the presence of a shear line 80 provided between the inner wall 82 of the cap hole 78 and the cap 76. When clamped therebetween, the shear line 80 rests simultaneously in complementary grooves 84 formed in the inner wall 82 and in complementary grooves 86 formed in the cap 76, as... Figure 10 As shown. In this way, even when the bow-shaped piston 60 is repeatedly pushed into and out of the piston pressure chamber 66, the interaction between the shear line 80 and the grooves 84 and 86 ensures that the gland 76 is firmly held in place.

[0045] While the gland 76 helps facilitate the formation of the necessary hydraulic seal between the inner surface 70 of the pressure chamber and the outer surface 68 of the piston, each gland seal may additionally include one or more additional inner gland seals 88 configured to engage the surface 68 of the bow piston 60 and to create a seal between the bow piston 60 and the gland 76. The inner gland seals 88 are typically rod seals. The gland 76 may additionally include a plurality of outer gland seals 90 positioned to engage the inner surface 82 of the gland bore 78 and configured to create a seal between the inner surface 82 and the gland 76. The outer gland seals 90 may include a plurality of O-ring seals. The structure of the gland sealing assembly 72 and its numerous sealing elements provide a robust hydraulic seal sufficient not only for hydraulic operation of the rotary actuator 32 but also to prevent hydraulic fluid leakage, at least in part, after repeated operation of the rotary actuator, caused by leakage from previously inadequate rotary actuator mechanisms. The design of the gland sealing assembly 72 further allows for an increase in the additional float of the gland assembly relative to the gland hole 78 of the pressure chamber assembly 64, and thus the rotary actuator is better able to tolerate dimensional deviations that fall within manufacturing tolerances.

[0046] Figure 11 The manifold block 34 is depicted as semi-transparent to show a plurality of internal channels 92 within it. The internal channels 92 are configured to deliver hydraulic fluid to at least each of the piston pressure chambers formed by the pressure chamber assembly 64. Typically, the manifold block 34 defines a first plurality of internal channels configured to deliver hydraulic fluid to a first piston pressure chamber and also defines a second plurality of internal channels configured to deliver hydraulic fluid to a second piston pressure chamber, such that by sequentially delivering hydraulic fluid to the first and second piston pressure chambers, the first rotor shaft can rotate and rotate in opposite directions.

[0047] As described above, the first rotor assembly 36 includes a first actuator housing 51, a first rotor shaft 46, and a plurality of crank arms 58 connecting the first rotor shaft 46 to a plurality of bow-shaped pistons 60. The plurality of bow-shaped pistons 60 connected to the first rotor shaft 46 may include a first group 94 of bow-shaped pistons 60 extending in a first rotational direction about the rotation axis 56; and a second group 96 of bow-shaped pistons 60 extending in a second opposite rotational direction about the rotation axis 56. Typically, the number of bow-shaped pistons in the first group 94 and the second group 96 is equal. Therefore, the rotary actuator 32 can be operated by increasing the hydraulic pressure in the piston pressure chambers by supplying hydraulic fluid to a first set of piston pressure chambers corresponding to the bow-shaped pistons of the first half 94, thereby causing each of the bow-shaped pistons 60 of the first half 94 to be ejected from its corresponding piston pressure chamber, thus causing rotation of the first rotor shaft 46 and actuation of the rotary actuator. Driven by the hydraulic pressure within the piston pressure chamber of the bow-shaped piston 60 in the first half 94, the rotor shaft can rotate until each of the crank arms 58 in the bow-shaped piston of the first half 94 encounters its corresponding rotation stop 98. Figure 8 As can be seen in the text.

[0048] The rotary actuator 32 can be restored to its initial configuration by reducing the hydraulic pressure applied to the bow piston 60 of the first half 94 and applying hydraulic pressure to the second plurality of second piston pressure chambers of the bow piston 60 for the second half 96, thereby causing the first rotor shaft 46 to rotate in the reverse direction until the crank arm 58 of the bow piston of the second half 96 encounters its corresponding rotary stop 98 again, and the actuator 32 returns to its initial configuration.

[0049] As described above, actuation of the rotary actuator 32 is primarily achieved by alternating pressurization and depressurization of the first and second plurality of piston pressure chambers. However, since the first actuator housing 51 is hermetically coupled to the manifold block 34 and completely surrounds the first pressure chamber assembly 64, an additional internal volume is created, defined by the outer surface 100 of the first pressure chamber assembly 64, the outer surface 102 of the first rotor shaft 46, and the inner surface 104 of the first actuator housing 51. This internal volume is referred to as the first return pressure volume 106.

[0050] Multiple bow-shaped pistons 60 connected to the first rotor shaft 46 can be connected to the first rotor shaft 46 in pairs. More specifically, the multiple bow-shaped pistons 60 can be connected to the first rotor shaft 46 in an arrangement exhibiting double rotational symmetry with respect to the rotation axis 56. That is, the arrangement of the bow-shaped pistons around the first rotor shaft can be symmetrical with respect to a 180-degree rotation of the first rotation axis 46 around the rotation axis 56. This double rotational symmetry can be, for example, in... Figure 6 , 7 See in 12.

[0051] As described above, the rotary actuator 32 may include a first rotor assembly 36 and a second rotor assembly 38, each coupled to the opposite side of the manifold block 34. Typically, the composition and construction of the second rotor assembly 38 are selected to be substantially the same as those of the first rotor assembly 36, and are symmetrical to the first rotor assembly 36 by rotating 180 degrees about a vertical axis of symmetry 108 orthogonal to the axis of rotation 56, such as... Figure 12 As shown, it depicts a rotary actuator 32 with the first actuator housing 51 and the second actuator housing 52 removed. Because the second rotor assembly 38 is symmetrical to the first rotor assembly 36, the second rotor assembly 38 also includes a rotor shaft, one end of which extends into a groove 44 formed in the manifold block 34, such that output lugs 42 are respectively connected to the inner end 45 of the first rotor shaft 46 and the inner end 47 of the second rotor shaft 48.

[0052] like Figure 12 As illustrated by the rotary actuator 32, each of the first rotor assembly 36 and the second rotor assembly 38 may include eight arc-shaped pistons 60 respectively attached to each of the first rotor shaft 46 and the second rotor shaft 48. Furthermore, the eight arc-shaped pistons 60 attached to each rotor shaft may include a first group of four arc-shaped pistons 60 extending about the rotation axis 56 in a first rotational direction, and a second group of four arc-shaped pistons 60 extending about the rotation axis 56 in a second and opposite rotational direction. The eight arc-shaped pistons 60 are further arranged in a manner exhibiting double rotational symmetry with respect to the rotation axis 56.

[0053] Because the volume of the rotary actuator 32 can be significantly smaller than that of a corresponding conventional linear actuator, the rotary actuator 32 can be advantageously integrated into the control surface actuator system 110, such as... Figure 13 As shown, the rotary actuator 32 can be coupled to the control surface 114 of the aircraft 10. The control surface actuator system 110 can be configured such that operation of the rotary actuator 32 actuates movement of the control surface 114. Alternatively, or further, the rotary actuator 32 can be coupled to the control surface 114 via an intermediate actuator arm.

[0054] and Figure 2 Compared to the actuator system, the rotary actuator 32 of the control system 110 can be completely enclosed within the wing 24, which has a very thin cross-section, such as... Figure 13 As shown. Therefore, the control system 110 is well-suited for use as a control system for wing control surfaces because the disclosed rotary actuator can be installed entirely within the internal space of the associated wing structure.

[0055] The various components of the rotary actuator disclosed herein can be made of any suitable material having the necessary physical properties, and in particular, of any suitable material already used in the manufacture of aircraft components. Specifically, the bow-shaped piston of the disclosed rotary actuator can be made of a stainless steel alloy conforming to AMS 5659 specifications, such as 15-5PH stainless steel. The surface of the bow-shaped piston can be further hardened by a high-velocity oxygen fuel (HVOF) coating, including, for example, tungsten carbide cobalt. The gland of the gland seal can be made of, for example, an aluminum-nickel bronze alloy conforming to AMS 4640 specifications.

[0056] The currently disclosed rotary actuator can be manufactured by any suitable machining method capable of providing the precision tolerances required by the hydraulic system, such as CNC machining. Alternatively or additionally, since the pressure chamber assembly particularly requires precise tolerances along the extended bow-shaped piston path, it may be advantageous to use additive manufacturing methods (i.e., 3D printing) to manufacture some or all of the components of the disclosed rotary actuator.

[0057] The rotary actuator disclosed herein can be used in methods for actuating aircraft control surfaces, wherein the reduced size, enhanced performance, and increased durability of the currently disclosed rotary actuator can improve aircraft control surface actuation.

[0058] This section describes the steps of an illustrative method for actuating aircraft control surfaces, such as... Figure 14 The flowchart 120 is shown. Where appropriate, references may be made to the components and systems that can be used to perform each step. These references are for illustrative purposes only and are not intended to limit the possible ways in which any particular step of the method can be performed.

[0059] Furthermore, based on this disclosure, it should be understood that additional steps may be performed without departing from the spirit of this disclosure or the claims. Although described below and Figure 14 The flowchart 120 describes the steps of each step, but not all of these steps need to be performed, and in some cases, they may be performed simultaneously or in a different order than that shown in the corresponding flowchart.

[0060] The illustrative method of flowchart 120 may include providing a rotary actuator 32, as illustrated in step 122 of flowchart 120 and as described above. The method may also include delivering pressurized hydraulic fluid via an inner passage 92 of manifold block 34 to a first pressure chamber assembly 64 to increase the hydraulic fluid pressure within the piston pressure chamber 66 of the first pressure chamber assembly 64, as illustrated in step 124 of flowchart 120. The method may also include rotating the first rotor shaft 46 by pushing an arcuate piston 66 disposed within the piston pressure chamber 66 of the first pressure chamber assembly 64 to translate about a rotation axis 56 of the first rotor shaft 46 due to the increased hydraulic fluid pressure within the piston pressure chamber 66, as illustrated in step 126 of flowchart 120. The method may also include moving an output lug 42 coupled to an inner end 45 of the first rotor shaft 46 by rotating the first rotor shaft, as illustrated in step 128 of flowchart 120. The method may also include moving the actuator interface arm 112 by moving the output lug 42, as illustrated in step 130 of flowchart 120. The method may also include actuating the aircraft control surface 114 by moving the actuator interface arm 112, as illustrated in step 132 of flowchart 120.

[0061] An illustrative method for actuating an aircraft control surface may optionally further include returning the aircraft control surface to its initial configuration by delivering pressurized hydraulic fluid to a second plurality of piston pressure chambers 66 of the bow-shaped piston 60 for the second half 96, thereby translating the second set of plurality of bow-shaped pistons 96 in opposite directions about the axis of rotation 56 of the first rotor shaft 46, as illustrated in step 134 of flowchart 120. The method may optionally further include reciprocating the actuator arm 112 by reversing the rotation of the first rotor shaft 46 and moving the output lug 42 that connects the inner end 45 of the first rotor shaft 46 to the actuator arm 112, as illustrated in step 136 of flowchart 120. The method may optionally further include returning the aircraft control surface 114 to its initial configuration by moving the actuator arm 114 to its initial position, as illustrated in step 140 of flowchart 120.

[0062] Examples, components, and alternatives A. Illustrative combinations and additional examples This section describes other aspects and features of the disclosed rotary actuator, aircraft control surface actuation system, and methods for actuating aircraft control surfaces. These features are presented as a series of paragraphs without limitation, some or all of which may be indicated by alphanumeric characters for clarity and efficiency. Each of these paragraphs may be combined with one or more other paragraphs and / or incorporated in any suitable manner with disclosures elsewhere in this application. Some of the following paragraphs explicitly reference and further limit the others, providing examples of, but not limited to, suitable combinations.

[0063] A1. A rotary actuator comprising: a manifold block; and a first rotor assembly mounted to the manifold block; wherein the first rotor assembly includes: a first rotor shaft extending into the manifold block; a plurality of bow-shaped pistons attached to the first rotor shaft, each bow-shaped piston being bent at a predetermined radial distance from the axis of rotation of the first rotor shaft, and each piston being attached to the first rotor shaft via a crank arm; a first pressure chamber assembly coupled to the manifold block, the first pressure chamber defining a plurality of piston pressure chambers configured to receive and at least partially surround each bow-shaped piston; and a plurality of gland seals disposed adjacent to the inlet of each piston pressure chamber and in... A seal is formed between the inner surface of the piston pressure chamber and the outer surface of the bow-shaped piston inserted therein; wherein each gland seal includes an inner seal configured to engage the surface of the bow-shaped piston and a plurality of outer seals configured to engage the inner surface of the piston pressure chamber, such that a hydraulic seal is formed between each piston pressure chamber and the bow-shaped piston inserted therein; the first rotor assembly is configured such that delivery of hydraulic fluid to the plurality of piston pressure chambers causes the bow-shaped piston disposed in each piston pressure chamber to translate about the axis of rotation of the first rotor shaft by the predetermined radial distance, thereby rotating the first rotor shaft.

[0064] A2. The rotary actuator according to paragraph A1, wherein the first group of the plurality of bow-shaped pistons extends about the rotation axis in a first rotational direction, and the second group of the plurality of bow-shaped pistons extends about the rotation axis in a second and opposite rotational direction, such that supplying hydraulic fluid to the first piston pressure chamber of the first group of the bow-shaped pistons causes rotation of the first rotor shaft, and supplying the hydraulic fluid to the second piston pressure chamber of the second group of the bow-shaped pistons causes reverse rotation of the first rotor shaft.

[0065] A3. The rotary actuator according to paragraph A1 or A2 further includes a first actuator housing that is hermetically coupled to the manifold block and surrounds the first pressure chamber assembly, such that the outer surface of the first pressure chamber assembly, the outer surface of the first rotor shaft, and the inner surface of the first actuator housing combine to define a first return pressure volume.

[0066] A4. The rotary actuator according to any of paragraphs A1-A3, wherein the inner end of the first rotor shaft extends into a groove formed in the manifold block; and further includes an output lug coupled to the inner end of the first rotor shaft, wherein the output lug is configured to be coupled to a control surface.

[0067] A5. The rotary actuator according to any of paragraphs A1-A4, wherein the plurality of bow-shaped pistons are coupled in pairs to the first rotor shaft in an arrangement having double rotational symmetry about the axis of rotation.

[0068] A6. The rotary actuator according to any of paragraphs A1-A5, wherein each gland seal is disposed within a gland hole formed in the inner surface of the corresponding piston pressure chamber.

[0069] A7. The rotary actuator according to paragraph A6, wherein each gland seal includes a gland that is held within the gland hole by a shear line disposed between the gland and the gland hole, the shear line engaging both the gland and the gland hole.

[0070] A8. The rotary actuator according to any of paragraphs A1-A7, wherein the inner seal comprises a rod seal.

[0071] A9. The rotary actuator according to any of paragraphs A1-A8, wherein the plurality of external seals comprises a plurality of O-ring seals.

[0072] A10. The rotary actuator according to any of paragraphs A1-A9, wherein the manifold block defines a plurality of internal channels configured to deliver hydraulic fluid to the piston pressure chamber.

[0073] A11. The rotary actuator according to paragraph A10, wherein the manifold block defines a first plurality of internal channels configured to deliver hydraulic fluid to the first piston pressure chamber, and further defines a second plurality of internal channels configured to deliver hydraulic fluid to the second piston pressure chamber, such that by sequentially delivering hydraulic fluid to the first and second piston pressure chambers, the first rotor shaft is capable of rotation and reverse rotation.

[0074] A12. The rotary actuator according to any of paragraphs A1-A11 further includes a second rotor assembly mounted to the manifold block on a side opposite to the first rotor assembly; wherein the rotation of the second rotor assembly about a vertical axis orthogonal to the axis of rotation is substantially symmetrical with respect to the first rotor assembly; and the inner end of the second rotor shaft of the second rotor assembly extends into a groove formed in the manifold block; and includes an output lug coupled to the inner ends of both the first rotor shaft and the second rotor shaft, wherein the output lug is configured to be coupled to a control surface.

[0075] A13. The rotary actuator according to paragraph A12, wherein each of the first and second rotor assemblies includes eight arc-shaped pistons attached to their respective rotor shafts; wherein each of the first and second rotor assemblies includes: a first group of four arc-shaped pistons extending about the axis of rotation in a first rotational direction, and a second group of four arc-shaped pistons extending about the axis of rotation in a second and opposite direction; such that supplying hydraulic fluid to the first piston pressure chamber of the first group of four arc-shaped pistons for each of the first and second rotor assemblies causes rotation of the combined first and second rotor shafts, and supplying the hydraulic fluid to the second piston pressure chamber of the second group of four arc-shaped pistons for each of the first and second rotor assemblies causes reverse rotation of the combined first and second rotor shafts.

[0076] B1. A control surface actuator system comprising: a control surface of an aircraft; a rotary actuator coupled to the control surface such that operation of the rotary actuator actuates movement of the control surface; wherein the rotary actuator includes: a manifold block; and first and second rotor assemblies mounted along a rotation axis to opposite sides of the manifold block; wherein each of the first and second rotor assemblies includes a rotor shaft extending along the rotation axis into the manifold block; a plurality of arcuate pistons attached to the rotor shaft, each piston being bent along a defined radial distance from the rotation axis of the rotor shaft, and each piston being attached to the rotor shaft via an intermediate crank arm; and a pressure chamber assembly coupled to the manifold block, the pressure chamber being configured to receive and at least partially A plurality of piston pressure chambers surround the plurality of bow-shaped pistons; a plurality of gland seals are disposed adjacent to the inlet of each piston pressure chamber and create a seal between the inner surface of the piston pressure chamber and the bow-shaped piston disposed therein; wherein each gland seal includes an inner seal configured to engage the bow-shaped piston and a plurality of outer seals configured to engage the inner surface of the piston pressure chamber, such that a hydraulic seal is formed between each piston pressure chamber and the bow-shaped piston inserted therein; and each rotor assembly is configured such that supplying hydraulic fluid to the plurality of piston pressure chambers causes the bow-shaped piston disposed in each piston pressure chamber to translate about the axis of rotation, thereby increasing the volume of the piston pressure chamber and thereby rotating the coupled rotor shaft.

[0077] B2. The control surface actuator system according to paragraph B1, wherein the control surface is one of the following: aileron, elevator, rudder, spoiler, wing flap, wing slat, air brake, control stick or trim plate.

[0078] B3. The control surface actuator system according to paragraph B1 or B2, wherein the rotary actuator is entirely disposed within the aircraft wing.

[0079] C1. A method of actuating an aircraft control surface, wherein the aircraft control surface is coupled to an actuator arm; comprising: providing a rotary actuator including: a manifold block; and a first rotor assembly mounted to the manifold block; wherein the first rotor assembly includes: a first rotor shaft extending into the manifold block; a plurality of arcuate pistons attached to the rotor shaft, each piston being bent along a defined radial distance from a rotation axis of the rotor shaft, and each piston being attached to the rotor shaft via an intermediate crank arm; and a first pressure chamber assembly coupled to the manifold block, the first pressure chamber being configured to receive... The manifold block at least partially surrounds a plurality of piston pressure chambers of the plurality of bow-shaped pistons; wherein the manifold block defines a plurality of internal channels for delivering hydraulic fluid to the piston pressure chambers; a plurality of gland seals are disposed adjacent to the inlet of each piston pressure chamber and create a seal between the inner surface of the piston pressure chamber and the bow-shaped piston disposed therein; wherein each gland seal includes an inner seal configured to engage a surface of the bow-shaped piston and a plurality of outer seals configured to engage the inner surface of the piston pressure chamber, such that a hydraulic seal is formed between each piston pressure chamber and the bow-shaped piston inserted therein. The first rotor assembly is configured such that supplying hydraulic fluid to the plurality of piston pressure chambers via the plurality of internal channels of the manifold causes the bow-shaped piston disposed in each piston pressure chamber to translate about the axis of rotation of the first rotor shaft, thereby rotating the first rotor shaft; and the inner end of the first rotor shaft extends into a groove formed in the manifold, wherein an output lug connects the inner end of the first rotor shaft to one end of the actuator arm, which is also connected to the aircraft control surface; pressurized hydraulic fluid is supplied to the first pressure chamber assembly via the internal channels of the manifold to increase the hydraulic fluid pressure in the piston pressure chamber of the first pressure chamber assembly; the first rotor shaft is rotated by pushing the bow-shaped piston disposed in the piston pressure chamber of the first pressure chamber assembly to translate about the axis of rotation of the first rotor shaft due to the increase in the hydraulic fluid pressure in the piston pressure chamber; the output lug connected to the inner end of the first rotor shaft is moved by rotating the first rotor shaft; the actuator arm is moved by moving the output lug; and the aircraft control surface is actuated by moving the actuator arm.

[0080] C2. The method according to paragraph C1, wherein the first group of plurality of bow-shaped pistons extends about the axis of rotation in a first rotational direction, and the second group of plurality of bow-shaped pistons extends about the axis of rotation in a second and opposite rotational direction; and the manifold block defines a second plurality of internal channels configured to deliver hydraulic fluid to the second piston pressure chamber; the method further includes: delivering pressurized hydraulic fluid to the second piston pressure chamber and stimulating the second group of plurality of bow-shaped pistons to translate in the opposite direction about the axis of rotation of the first rotor shaft, and causing the first group of plurality of bow-shaped pistons disposed in the first piston pressure chamber to reciprocate about the axis of rotation of the first rotor shaft, thereby causing the first rotor shaft to rotate in the opposite direction; reciprocating the actuator arm by reciprocating the first rotor shaft and moving the inner end of the first rotor shaft to the output lug of the actuator arm; and restoring the aircraft control surface to its initial configuration by moving the actuator arm to its initial position.

[0081] C3. The method according to paragraph C1 or C2, wherein providing the rotary actuator includes providing a second rotor assembly mounted on the manifold block on a side opposite to the first rotor assembly, the second rotor assembly being substantially mirror-symmetrical to the first rotor assembly about a plane bisecting the manifold block orthogonal to the axis of rotation, and an inner end of a second rotor shaft of the second rotor assembly extending into the groove formed in the manifold block, and wherein the output lug is additionally coupled to the inner end of the second rotor shaft.

[0082] C4. The method according to paragraph C3, wherein providing the rotary actuator includes providing first and second rotor assemblies, each of the first and second rotor assemblies including eight bow-shaped pistons attached to each of the first and second rotor shafts.

[0083] C5. The method according to paragraph C4, wherein providing the rotary actuator includes providing first and second rotor assemblies, each of the first and second rotor assemblies including eight bow-shaped pistons attached to each of the first and second rotor shafts, wherein each of the first and second rotor assemblies includes a first set of four bow-shaped pistons extending about the rotation axis in a first rotational direction in a manner having double rotational symmetry about the rotation axis, and a second set of four bow-shaped pistons extending about the rotation axis in a second and opposite rotational direction.

[0084] C6. The method according to any of paragraphs C1-C5, wherein the aircraft control surface is a wing control surface, and providing the rotary actuator includes mounting the rotary actuator entirely within the internal volume of the wing structure.

[0085] Advantages, features and benefits The rotary actuators disclosed herein, including control surface actuator systems incorporating rotary actuators and methods for actuating control surfaces (which include the operation of the rotary actuators), offer significant advantages compared to existing linear actuator designs used for actuating aircraft control surfaces.

[0086] In contrast to linear actuators (which must mechanically convert the generated linear motion into rotary motion that is incompatible with the limitations of the available operating volume), the disclosed rotary actuator is configured to directly generate rotary motion.

[0087] As wing thickness decreases, the volume available for a control surface actuator system, including a linear actuator, becomes limited. At least a portion of the linear actuator may be forced to protrude beyond the wing interior, requiring a bubble or fairing to enclose the protrusion and resulting in reduced aerodynamic characteristics. Since the rotary actuator described herein requires a smaller operating volume, it can even be entirely incorporated into a relatively thin wing structure. Furthermore, because the actuator assembly can be positioned closer to the wing's trailing edge, a larger volume within the wing can be used for fuel capacity.

[0088] Because rotary actuators directly generate rotational motion, there is no need for a connection to a short lever arm to provide leverage for manipulating the control surface, and the control surface can be directly actuated. Furthermore, rotary actuators offer higher mechanical reliability compared to conventional toggle actuators sized for the same application. Toggle actuator designs require bearings larger than the rotary actuator itself to compensate for nonlinear loads applied by the actuator. The rotary actuator described herein produces significantly reduced bearing loads, resulting in less bearing wear and higher actuator reliability.

[0089] The toggle lever actuator must be mounted to the wing spars and requires structural reinforcements to provide sufficient stability to withstand the loads applied to the actuator during operation. In contrast, the rotary actuator does not require additional reinforcements, resulting in a lighter fuselage. Furthermore, due to its compact design, the rotary actuator is less susceptible to buckling loads.

[0090] Compared to previous versions of rotary actuators, the rotary actuator described here is a significant improvement because the disclosed gland seal provides reliable hydraulic operation without the common hydraulic leakage observed in existing systems, resulting in the rotary actuator requiring less maintenance and having a longer service life compared to previous rotary actuators.

[0091] in conclusion The disclosure described above may cover multiple different examples with independent utility. Although each of them has been disclosed in its preferred form(s), the specific examples disclosed and shown herein should not be considered limiting, as many variations are possible. The use of section headings within this disclosure is solely for organizational purposes. The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various elements, features, functions, and / or characteristics disclosed herein. Certain combinations and sub-combinations considered novel and non-obvious are specifically pointed to in the following claims. Other combinations and sub-combinations of features, functions, elements, and / or characteristics may be claimed in applications claiming priority to this or related applications. Such claims (whether broader, narrower, identical, or different in scope from the initial claims) are also considered to be included within the subject matter of this disclosure.

Claims

1. A rotary actuator (32), comprising: Manifold block (34); and The first rotor assembly (36) is mounted to the manifold block (34); The first rotor assembly (36) includes: The first rotor shaft (46) extends into the manifold block (34); Multiple bow-shaped pistons (60) are attached to the rotor shaft, each bow-shaped piston being bent at a predetermined radial distance from the axis of rotation (56) of the first rotor shaft (46), and each piston being attached to the first rotor shaft (46) via a crank arm (58). A first pressure chamber assembly (64) is connected to the manifold block (34), the first pressure chamber defining a plurality of piston pressure chambers (66), each piston pressure chamber being configured to receive and at least partially surround a corresponding bow-shaped piston (60). Multiple gland seals (72) are disposed adjacent to the inlet (74) of each piston pressure chamber (66) and create a seal between the inner surface (70) of the piston pressure chamber (66) and the outer surface (68) of the corresponding bow-shaped piston inserted therein; Each gland seal (72) includes an inner seal (88) configured to engage the surface of the bow-shaped piston (60) and a plurality of outer seals (90) configured to engage the inner surface (70) of the piston pressure chamber (66), such that a hydraulic seal is formed between each piston pressure chamber (66) and the corresponding bow-shaped piston (60) inserted therein. The first rotor assembly (36) is configured such that delivering hydraulic fluid to the plurality of piston pressure chambers (66) causes the bow-shaped piston (60) disposed in each piston pressure chamber (66) to translate about the axis of rotation (56) of the first rotor shaft (46) by the set radial distance, thereby causing the first rotor shaft (46) to rotate.

2. The rotary actuator according to claim 1, wherein, The plurality of bow-shaped pistons (60) includes a first group (94) of the plurality of bow-shaped pistons extending about the rotation axis (56) in a first rotational direction and a second group (96) of the plurality of bow-shaped pistons extending about the rotation axis (56) in a second and opposite rotational direction, such that supplying hydraulic fluid to the first group (94) of the bow-shaped pistons to a plurality of first piston pressure chambers (66) causes rotation of the first rotor shaft (46), and supplying the hydraulic fluid to a second plurality of second piston pressure chambers of the second group (96) of the bow-shaped pistons causes a reverse rotation of the first rotor shaft (46).

3. The rotary actuator according to claim 1 or 2, further comprising a first actuator housing (51) hermetically coupled to the manifold block (34) and surrounding the first pressure chamber assembly (64), such that the outer surface (100) of the first pressure chamber assembly (64), the outer surface (102) of the first rotor shaft (46) and the inner surface (104) of the first actuator housing (51) combine to define a first return pressure volume (106).

4. The rotary actuator according to claim 1 or 2, wherein, The inner end (45) of the first rotor shaft (46) extends into a groove (44) formed in the manifold block (34); it also includes an output lug (42) coupled to the inner end (45) of the first rotor shaft (46), wherein the output lug (42) is configured to be coupled to a control surface (114).

5. The rotary actuator according to claim 1 or 2, wherein, The plurality of bow-shaped pistons (60) are arranged in pairs to the first rotor shaft (46) with double rotational symmetry about the axis of rotation (56).

6. The rotary actuator according to claim 1 or 2, wherein, Each gland seal (72) is disposed within a gland hole (78), which is formed in the inner surface (70) of its corresponding piston pressure chamber (66).

7. The rotary actuator according to claim 1 or 2, wherein, The manifold block (34) defines a plurality of internal channels (92) configured to deliver hydraulic fluid to the piston pressure chamber (66).

8. The rotary actuator according to claim 2, wherein, The manifold block (34) defines a first plurality of internal channels (92) configured to deliver hydraulic fluid to the first piston pressure chamber (66), and also defines a second plurality of internal channels (92) configured to deliver hydraulic fluid to the second piston pressure chamber, such that by sequentially delivering hydraulic fluid to the first and second piston pressure chambers, the first rotor shaft (46) can rotate and rotate in the opposite direction.

9. The rotary actuator of claim 2, further comprising a second rotor assembly (38) mounted to the manifold block (34) on the side opposite to the first rotor assembly (36). in, The rotation of the second rotor assembly (38) about a vertical axis (108) orthogonal to the rotation axis (56) is substantially symmetrical with that of the first rotor assembly (36); and The inner end (47) of the second rotor shaft (48) of the second rotor assembly (38) extends into the groove (44) formed in the manifold block (34); It also includes an output lug (42) connected to the inner ends of the first rotor shaft (46) and the second rotor shaft (48), wherein the output lug (42) is configured to be connected to the control surface (114).

10. The rotary actuator according to claim 9, wherein, Each of the first and second rotor assemblies includes eight bow-shaped pistons (60) attached to its respective rotor shaft. Each of the first and second rotor assemblies includes a first group (94) of four bow-shaped pistons extending about the rotation axis (56) in a first rotational direction; and a second group (96) of four bow-shaped pistons extending about the rotation axis (56) in a second and opposite rotational direction. The first piston pressure chamber (66) for each of the first and second rotor assemblies that delivers hydraulic fluid to the four bow-shaped pistons of the first group (94) causes rotation of the first and second rotor shafts of the combination, and the second piston pressure chamber for each of the first and second rotor assemblies that delivers the hydraulic fluid to the four bow-shaped pistons of the second group (96) causes rotation of the first and second rotor shafts of the combination in the opposite direction.

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