A pneumatically driven drive device for helicopter Gurney flaps

Abstract

This invention discloses a pneumatically driven drive device for a helicopter Gurney flap, relating to the field of rotorcraft technology, capable of changing the extension length in a certain altitude direction. In this invention, a cam driven by an airbag and fixed to a housing, a connecting rod driven by the cam, a movable hinge shaft connecting the connecting rod and the Gurney flap, and a housing of the mechanical drive device are included. When the piston reciprocates, the volume of the working fluid in the piston cylinder, flexible guide tube, and airbag changes, thereby driving the cam to deflect around the camshaft via the cam extension plate. Simultaneously, a connecting rod hinged at one end to the cam performs planar motion under the rotation of the cam, and its other end is connected to the inner extension plate of the Gurney flap via a movable hinge shaft. A sliding pin is provided on the housing of the device fixed to the blade skin to support and constrain the inner extension plate, allowing the extended side of the Gurney flap to extend and retract perpendicular to the blade chord.

Description

Technical Field

[0001] This invention relates to the field of rotorcraft technology, and more particularly to a pneumatically driven drive device for helicopter guinea flaps. Background Technology

[0002] Helicopters are vertical takeoff and landing aircraft that use rotors as their main source of lift. They are widely used and related improvements are constantly being made. One of the directions of improvement is the improvement of flaps.

[0003] As an alternative to conventional flaps, the Gurney flap is small in size and has a strong lift-enhancing capability, showing great potential in improving rotor performance, increasing payload, and enhancing helicopter rotor control during hovering and forward flight, as well as vibration control and flutter suppression. However, current research has found that the Gurney flap's lift-enhancing and vibration-damping capabilities are mixed when extended at different heights and facing different aerodynamic environments.

[0004] Therefore, how to implement a variable-height Grylls flap drive scheme has become a research topic. Summary of the Invention

[0005] An embodiment of the present invention provides a pneumatically driven drive device for a helicopter guinea flap, which can extend by varying its length in a certain height direction.

[0006] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0007] The device is mounted on the Gurney flap and comprises: a piston actuator (1), a flexible guide tube (2), an airbag (3), a cam (4), a connecting rod (5), a movable hinge (6), a mounting point (7), and a mechanical housing (8). One end of the piston actuator (1) is a fixed end, and the other end is a guide tube connection end. The fixed end of the piston actuator (1) is fixed to the rotor hub, and the guide tube connection end of the piston actuator (1) is connected to the drive part of the device via the flexible guide tube (2). The drive part of the device is mounted on... The arrangement (7) on the Gurney flap, and the arrangement (7) is offset from the main beam of the blade of the Gurney flap along the blade chord direction, the drive part of the device includes: airbag (3), cam (4), connecting rod (5), movable hinge (6) and mechanical device housing (8); flexible duct (2) is connected to two airbags (3); cam (4) is hinged to one end of connecting rod (5), and the other end of connecting rod (5) is hinged to the inner plate (71) of Gurney flap through movable hinge (6); mechanical device housing (8) is fixed to the skin of the blade of the Gurney flap.

[0008] The piston actuator (1) consists of a pair of piston structures. Each piston structure includes a piston rod (11), a piston head (12), and a piston cylinder (13). The piston head (12) is mounted on the top of the piston rod (11). A piston ring (121) is mounted on the edge of the piston head (12). The piston ring (121) has a groove on its side. The piston rod (11) is mounted inside the piston cylinder (13), and the piston ring (121) is press-fitted with the inner wall of the piston cylinder (13).

[0009] Flexible conduits (2) are installed in pairs, and one piston structure is connected to one flexible conduit (2); and airbags (3) also appear in pairs, with one piston structure connected to one airbag (3) through one flexible conduit (2); the flexible conduit (2) is bonded to the top of the piston cylinder (13). The part of the flexible conduit (2) exposed outside the blade is the flexible conduit extension side (21), wherein the flexible conduit extension side (21) is sealed to the bottom of the piston cylinder (13) to form a piston-flexible conduit connection (211); the flexible conduit (2) extends into the blade at the trailing edge of the blade root, and the part extending into the blade is the flexible conduit embedded side (22), wherein the flexible conduit embedded side (22) is arranged radially along the blade, and after passing through the opening (81) of the mechanical device housing, it is sealed to the airbag (3) to form an airbag-flexible conduit connection (221). The cross-sectional areas of the piston-flexible conduit connection (211) and the airbag-flexible conduit connection (221) are both designed with a smooth transition to avoid water hammer effect.

[0010] A pair of airbags (3) are divided into an upper airbag (31) and a lower airbag (32). The upper airbag (31) and the lower airbag (32) are both placed between the cam extension plate (41) and the mechanical device housing (8). The pressure difference between the upper airbag (31) and the lower airbag (32) acts on the cam extension plate (41), causing the cam (4) to rotate around the cam shaft (42), thereby driving the connecting rod (5) hinged to the lower end (43) of the cam to move. Each airbag (3) is made of a fully formed, sealed, flexible material, and each airbag (3) is flat.

[0011] The mechanical housing (8) has a blind hole at the axis of the camshaft (42) and extends the camshaft (42) into the blind hole; the camshaft (42) deflects under the external force provided by the cam extension plate (41), driving the lower end (43) of the cam to rotate; a miniature displacement sensor is provided on the side of the cam plate (41).

[0012] The contact point (82) between the end of the extension plate (411) of the cam and the housing of the mechanical device is an arc surface contact, and the radius of the arc surface is: the distance from the center of the cam shaft (42) to the uppermost point of the end of the extension plate on the two-dimensional airfoil section.

[0013] One end of the connecting rod (5) is hinged to the lower end (43) of the cam; the inner plate (71) is provided with a slot (711) for the Gurney flap, and a sliding pin (83) is fixed on the mechanical housing near the rear edge. The sliding pin (83) passes through the slot (711) of the Gurney flap to constrain the movement of the Gurney flap. The inner plate (71) of the Gurney flap and the outer side (72) of the Gurney flap have pre-set ribs (73) on the inner side of the connection, and chamfers are made at the corresponding positions on the skin; the slot (711) of the Gurney flap cooperates with the sliding pin (83) on the mechanical housing, and each side of the slot (711) of the Gurney flap and the sliding pin (83) should be chamfered; the neutral surface of the outer side (72) of the Gurney flap has a reserved length longer than the outer side of the skin, and the specified length is one-hundredth of the chord length.

[0014] A pair of piston actuators (1) are fixed on the rotor hub; an actuator fixing device (10) is pre-welded on the rotor hub, the shape of the mounting hole of the actuator fixing device (10) matches the fixed end of the piston actuator (1), and the fixed end of the piston actuator (1) is inserted into the mounting hole of the actuator fixing device (10) and fits tightly with the actuator fixing device (10); the fixing device (10) has holes to allow the flexible guide tube (2) and the piston rod (11) to pass through respectively; a limit cover (101) is installed on the edge of the mounting hole of the actuator fixing device (10) by bolts, and the inner shape of the limit cover (101) matches the cross-section of the piston actuator (1).

[0015] The pneumatically driven drive device for a helicopter Gurney flap provided in this embodiment of the invention comprises a cam driven by an airbag and fixed to the outer shell, a connecting rod driven by the cam, a movable hinge shaft connecting the connecting rod and the Gurney flap, and the outer shell of the mechanical drive device. When the piston reciprocates, the volume of the working fluid within the piston cylinder, flexible guide tube, and airbag changes, thereby driving the cam to deflect around the camshaft via the cam's extension plate. Simultaneously, a connecting rod hinged at one end to the cam performs planar motion under the cam's rotation, and its other end is connected to the Gurney flap's inner extension plate via a movable hinge shaft. A sliding pin is provided on the outer shell of the device, fixed to the blade skin, to support and constrain the inner extension plate, allowing the extended side of the Gurney flap to extend and retract perpendicular to the blade chord. Therefore, this embodiment allows for changes in the extension length in a certain height direction, and the variable-height Gurney flap is driven by a pneumatically driven device without an air source. Furthermore, a negative feedback control system ensures the control accuracy and stable operation of the entire device. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1a , Figure 1b A schematic diagram of the overall assembly structure of the pneumatically driven Gurney flap drive device provided in an embodiment of the present invention;

[0018] Figure 2a , Figure 2b A detailed schematic diagram of the piston actuation device provided in an embodiment of the present invention;

[0019] Figure 3 A schematic diagram showing the details of the flexible catheter provided in an embodiment of the present invention;

[0020] Figure 4 A schematic diagram showing the details of the airbag provided in an embodiment of the present invention;

[0021] Figure 5 A schematic diagram showing the details of the cam provided in an embodiment of the present invention;

[0022] Figure 6 This is a schematic diagram of the connecting rod structure provided in an embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram of the flexible catheter implantation side and movable hinge structure provided in an embodiment of the present invention;

[0024] Figure 8 A schematic diagram showing the details of the Gurney flap provided in an embodiment of the present invention;

[0025] Figure 9 A schematic diagram showing the detailed outer casing of the mechanical device provided in an embodiment of the present invention;

[0026] Figure 10 This is a schematic diagram of the motion envelope of a mechanical device provided in an embodiment of the present invention;

[0027] Figure 11 a) A block diagram and mechanical schematic diagram of the control system provided in the embodiments of the present invention;

[0028] Figure 11 b) is a schematic diagram of the actuator fixing device provided in an embodiment of the present invention;

[0029] Figure 12 This is a schematic diagram of the actuator fixing device structure assembly provided in an embodiment of the present invention;

[0030] Figure 13 This is a schematic diagram of the structural assembly of the actuator fixing device and the piston actuator provided in an embodiment of the present invention;

[0031] In the attached diagram, the numbers represent: piston actuator-1, piston rod-11, piston head-12, piston cylinder-13, piston ring-121, flexible conduit-2, flexible conduit extension side-21, flexible conduit embedded side-22, flexible conduit connection-211 / 221, airbag-3, upper airbag-31, lower airbag-32, cam-4, cam extension plate-41, camshaft-42, lower end of cam-43, cam... Extension plate end - 411, connecting rod - 5, movable hinge pin - 6, Gurney flap - 7, Gurney flap inner extension plate - 71, Gurney flap slot - 711, Gurney flap outer extension side - 72, Gurney flap connection rib - 73, mechanical device housing - 8, mechanical device opening - 81, mechanical device housing and cam extension plate contact surface - 82, sliding pin - 83, counterweight bar - 9, actuator fixing device - 10, limit cover - 101. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Embodiments of the present invention will be described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in the specification of the present invention means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0033] This invention provides a pneumatically driven drive device for helicopter Gurney flaps, such as... Figure 1a , Figure 1b , Figure 12 As shown, the device is mounted on the Gurney flap and its components include: a piston actuator (1), a flexible guide (2), an airbag (3), a cam (4), a connecting rod (5), a movable hinge (6), an arrangement (7), and a mechanical housing (8).

[0034] One end of the piston actuator (1) is a fixed end, and the other end is a conduit connection end. The fixed end of the piston actuator (1) is fixed on the rotor hub, and the conduit connection end of the piston actuator (1) is connected to the drive part of the device through a flexible conduit (2).

[0035] The drive portion of the device is mounted at a location (7) on the Gurney flap, and the location (7) is offset from the main beam of the Gurney flap blade along the blade chord. The drive portion of the device includes: an airbag (3), a cam (4), a connecting rod (5), a movable hinge (6), and a mechanical housing (8). A flexible conduit (2) extends into the drive portion and connects to the two airbags (3).

[0036] The cam (4) is hinged to one end of the connecting rod (5), and the other end of the connecting rod (5) is hinged to the inner plate (71) of the Gurney flap via a movable hinge pin (6). The movable hinge pin (6) at the connection between the cam (4) and the connecting rod (5) is fixed to the cam to prevent excessive stress on the lower end (43) of the cam. Due to structural size limitations, a free hinge pin cannot be used at the lower end (43) of the cam. When installing the connecting cam (4) and the connecting rod (5), the outline of the free hinge pin can be bored out of the lower end (43) of the cam first. After the free hinge pin is fitted onto the connecting rod (5), the free hinge pin is welded to the lower end (43) of the cam, and then the cam (4) is ground. The connection between the connecting rod (5) and the Gurney flap (7) uses a free hinge pin.

[0037] The mechanical housing (8) is fixedly connected to the skin of the blades of the Gurney flap. The mechanical housing (8) employs a fitted design: such as... Figure 10 After analyzing the motion envelope of the mechanical structure, in order to have good vibration resistance and structural characteristics, the inner wall of the mechanical structure shell (8) is fitted with the motion envelope. The mechanical device is easy to process the blades after being encapsulated.

[0038] In this embodiment, the piston actuator (1) consists of a pair of piston structures. Each piston structure comprises a piston rod (11), a piston head (12), and a piston cylinder (13). The piston head (12) is mounted on the top of the piston rod (11). A piston ring (121) is mounted on the edge of the piston head (12). The piston ring (121) has a groove on its side. The groove on the side of the piston ring (121) is installed with an interference fit to achieve a good seal. The piston rod (11) is installed inside the piston cylinder (13), and the piston ring (121) is interference-fitted with the inner wall of the piston cylinder (13).

[0039] The flexible conduits (2) are installed in pairs, with one piston structure connected to one flexible conduit (2). The airbags (3) also appear in pairs, with one piston structure connected to one airbag (3) via a flexible conduit (2). The flexible conduit (2) is bonded to the top of the piston cylinder (13). Specifically, the portion of the flexible conduit (2) exposed outside the blade is the flexible conduit extension side (21), which is sealed to the bottom of the piston cylinder (13) to form a piston-flexible conduit connection (211). The flexible conduit extension side (21) can have a free length to avoid interfering with the blade's swinging and twisting motion. The flexible conduit (2) extends into the blade at the trailing edge of the blade root, specifically by opening a hole at the trailing edge of the blade root skin to allow the flexible conduit (2) to penetrate deep into the blade. The part extending into the blade is the flexible conduit embedded side (22), wherein the flexible conduit embedded side (22) is arranged radially along the blade, and after passing through the opening (81) of the mechanical device housing, it is sealed and bonded to the airbag (3) to form the airbag-flexible conduit connection (221).

[0040] In practical applications, a pair of flexible conduits (2) are connected at both ends to the piston cylinder (13) and the airbag (3). The flexible conduit (2) is glued to the top of the piston cylinder (13), and after reserving a certain free length, it extends into the blade at the trailing edge of the blade root. Due to the complexity of the blade hub structure, in order to avoid interfering with the normal operation of the blade hub, the pipeline routing should be arranged reasonably according to different blade hub structures, or a guide tube can be arranged separately. At the trailing edge of the blade root, the skin and the flexible conduit (2) are fixedly bonded with elastic sealant. The embedded side (22) of the flexible conduit is arranged radially along the blade, and after passing through the outer shell (8) of the mechanical device, it is sealed and glued to the airbag (3). In actual production, the blade is molded. In order to avoid obstruction of the permeability of the flexible conduit (2), the embedded side (22) of the flexible conduit can be made of carbon material, and it is glued and sealed to the extended side (21) of the flexible conduit at the trailing edge of the blade root.

[0041] Furthermore, the cross-sectional area of ​​the piston-flexible conduit connection (211) and the airbag-flexible conduit connection (221) can both adopt a smooth transition design to avoid water hammer effect.

[0042] The drive unit designed in this embodiment can be installed in pairs on the rotor hub. When the airborne fly-by-wire control system is subjected to force on the piston rod (11), the piston head (12) does work on the working fluid in the piston cylinder (13), thereby compressing / expanding the working fluid. The working fluid penetrates the rotor blade through a pair of flexible conduits (2) at the trailing edge of the rotor root, reaching the arrangement (7) on the Gurney flap, where the flexible conduits (2) are connected to a pair of airbags (3). The two areas containing the working fluid are completely sealed and independent, and in order to ensure the anti-interference of the entire device, the gauge pressure of both areas is at a high level. Since the actuation direction of the pair of piston rods (11) is opposite, the volume change trend of the working fluid in the upper airbag (31) and the lower airbag (32) is also opposite, thereby changing the deflection angle of the cam (4). When the cam (4) deflects, it drives the connecting rod (5) to perform rigid body planar motion, and then the connecting rod (5) drives the Gurney flap through the movable hinge (6). When the device is in mechanical motion, the outer casing (8) of the mechanical device is fixed to the skin of the blade and constrained and supported by a pair of sliding pins (83). In addition, a miniature displacement sensor is provided at the cam (4) for feedback to the fly-by-wire control system.

[0043] In a preferred embodiment, a pair of airbags (3) are divided into an upper airbag (31) and a lower airbag (32). Both the upper airbag (31) and the lower airbag (32) are placed between the cam extension plate (41) and the mechanical device housing (8). The pressure difference between the upper airbag (31) and the lower airbag (32) acts on the cam extension plate (41), causing the cam (4) to rotate around the cam shaft (42), thereby driving the connecting rod (5) hinged to the lower end (43) of the cam to move. Each airbag (3) is made of a fully formed sealing flexible material, and each airbag (3) is flat. The sealing flexible material is a material with an elastic modulus greater than or equal to 1.4 GPa. Nylon material with an elastic modulus of 1.4 GPa can be used directly, but in order to avoid wasting energy, the elastic modulus of the material selected for the entire pneumatic sealing area should be much larger than the elastic modulus of nylon material (1.4 GPa).

[0044] In this embodiment, the mechanical housing (8) has a blind hole at the axis of the camshaft (42), and the camshaft (42) extends into the blind hole. The camshaft (42) deflects under the external force provided by the cam extension plate (41), causing the lower end (43) of the cam to rotate. A miniature displacement sensor is provided on the side of the cam plate (41).

[0045] The contact point (82) between the end of the cam extension plate (411) and the housing of the mechanical device is an arc surface contact. The radius of the arc surface is the distance from the center of the camshaft (42) to the uppermost point of the end of the extension plate on the two-dimensional airfoil section. Specifically, the constraint of the camshaft (42) mainly comes from the housing of the mechanical device (8), which only has the degree of freedom of rotation about the radial direction. In actual manufacturing, the housing of the mechanical device (8) opens a blind hole at the axis of the camshaft (42) and extends the camshaft (42) into the blind hole. When installing the camshaft (42), the linear elasticity of the material of the housing of the mechanical device (8) is used to align the camshaft (42) with the blind hole and snap it in. A micro displacement sensor is set on the side of the cam plate (41), and its circuit is consistent with the flexible conduit embedded side (22) to provide feedback signals. The airborne fly-by-wire control system drives the piston rod (11) and uses the micro displacement sensor to calculate and measure the deflection angle of the cam extension plate (41) to feed back to the airborne fly-by-wire control system.

[0046] In this embodiment, one end of the connecting rod (5) is hinged to the lower end (43) of the cam. The inner plate (71) is provided with a slot (711) for the Gurney flap, and a sliding pin (83) is fixed on the mechanical housing near the rear edge. The sliding pin (83) passes through the slot (711) of the Gurney flap to constrain the movement of the Gurney flap. Ribs (73) are preset on the inner side of the connection between the inner plate (71) of the Gurney flap and the outer side (72) of the Gurney flap, and chamfers are made at the corresponding positions on the skin to strengthen the structure of the connection and maximize the use of the blade trailing edge space at 90% chord length. The slot (711) of the Gurney flap cooperates with the sliding pin (83) on the mechanical housing. To prevent jamming, the edges of the slot (711) of the Gurney flap and the sliding pin (83) should be chamfered. The neutral surface of the extended side (72) of the Gurney flap has a specified length that is longer than the outer side of the skin, and the specified length is one-hundredth of the chord length, in order to obtain good lift performance.

[0047] In this embodiment, a pair of piston actuators (1) are fixed to the propeller hub. It should be noted that the piston actuators appear in pairs, each with a piston rod. When describing these two piston rods, they are referred to as "a pair of piston rods". An actuator fixing device (10) is pre-welded to the propeller hub. The shape of the mounting hole of the actuator fixing device (10) matches the fixed end of the piston actuator (1). After the fixed end of the piston actuator (1) is inserted into the mounting hole of the actuator fixing device (10), it fits tightly against the actuator fixing device (10). The fixing device (10) has openings to allow the flexible guide tube (2) and the piston rod (11) to pass through, respectively. At the edge of the mounting hole of the actuator fixing device (10), a limit cover (101) is installed by bolts. The inner shape of the limit cover (101) matches the cross-section of the piston actuator (1).

[0048] In practical applications, considering the wear and sealing of the piston actuator, it needs to be replaced periodically and should not be directly welded to the propeller hub. A fixing device (10) can be pre-welded onto the propeller hub, such as... Figure 13 The actuator fixing device (10) fits tightly against the piston actuator (1) and is equipped with a bolt-connected limit cap (101) that can be disassembled. The fixing device (10) has openings at both the top and bottom for the flexible guide tube (2) and piston rod (11) to pass through, respectively. Considering that the large vibrations of the helicopter during actual use can easily loosen the bolts, these bolts should be included in the pre-flight maintenance plan. In terms of materials, a traditional aluminum alloy piston, mainstream steel piston rings, and a 45# steel piston rod are used, while the fixing device is made of lightweight aluminum alloy. For a compact structure, the piston rod and piston are connected by welding.

[0049] Optionally, a counterweight (9) is installed in the blade spars to meet the blade's design requirements for the center of gravity. The cam (4), connecting rod (5), Gurney flap, and mechanical housing (8) are all made of aluminum alloy, and the movable hinge is made of 40Cr. After the entire structure is connected and installed, the device inside the skin can be placed in its designed position and sent for molding along with the flange strip, spars, and filling material.

[0050] The design concept of this embodiment is mainly based on the different requirements of the Gurney flap in different flight states such as forward flight and hovering of a helicopter. A flexible drive device capable of adjusting the height of the Gurney flap was designed. Specifically, it includes a pair of piston actuators mounted on the rotor hub, a pair of flexible guides placed inside the rotor blades, a pair of airbags connected to the flexible guides, and other structures or components housed within the mechanical device housing. During operation, a cam driven by the airbag and fixed to the housing, a connecting rod driven by the cam, a movable hinge shaft connecting the connecting rod and the Gurney flap, and the housing of the mechanical drive device are all involved. When the piston reciprocates, the volume of the working fluid in the piston cylinder, flexible guides, and airbag changes, thereby driving the cam to deflect around the camshaft through the cam's extension plate. Simultaneously, a connecting rod hinged at one end to the cam performs planar motion under the rotation of the cam, and its other end is connected to the inner extension plate of the Gurney flap through a movable hinge shaft. A sliding pin is provided on the device housing fixed to the rotor blade skin to support and constrain the inner extension plate, allowing the extended side of the Gurney flap to extend and retract perpendicular to the rotor blade chord.

[0051] In summary, this embodiment achieves a change in the extension length of the Gurney flap at a certain height. The variable-height Gurney flap is driven by a pneumatic mechanical device without an air source, and a negative feedback control system ensures the control accuracy and stable operation of the entire device. Specifically: 1. The entire device designed in this embodiment adopts a gas-free solution, eliminating the need for exchanging working fluid with the outside environment. From the piston actuator to the flexible duct to the airbag, the entire system is sealed, like a balloon. This differs from other pneumatic transmission devices (which often require compressors and other equipment). It achieves complete isolation of the working fluid from the outside environment throughout the process from the piston actuator to the flexible duct and then to the airbag. This eliminates the need for traditional pneumatic equipment such as compressors and valves in the entire pneumatic transmission device. 2. The device designed in this embodiment is actually a negative feedback system, which offers significantly higher accuracy than systems without feedback. The stability of the control system is calculated based on the Nyquist stability criterion during the design phase, thereby ensuring the control accuracy and stable operation of the entire device.

[0052] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The above descriptions are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A pneumatically driven drive device for use in helicopter Gurney flaps, characterized in that, The device is mounted on the Gurney flap and its components include: a piston actuator (1), a flexible guide (2), an airbag (3), a cam (4), a connecting rod (5), a movable hinge (6), an arrangement (7), and a mechanical housing (8). One end of the piston actuator (1) is a fixed end and the other end is a conduit connection end. The fixed end of the piston actuator (1) is fixed on the paddle hub, and the conduit connection end of the piston actuator (1) is connected to the drive part of the device through a flexible conduit (2). The drive part of the device is mounted on the arrangement (7) on the Gurney flap, and the arrangement (7) is offset from the main beam of the blade of the Gurney flap along the blade chord. The drive part of the device includes: airbag (3), cam (4), connecting rod (5), movable hinge (6) and mechanical housing (8). The flexible catheter (2) is connected to two airbags (3); The cam (4) is hinged to one end of the connecting rod (5), and the other end of the connecting rod (5) is hinged to the inner plate (71) of the Gurney flap through the movable hinge shaft (6). The housing (8) of the mechanical device is fixedly connected to the skin of the blade of the Gurney flap; The piston actuator (1) consists of a pair of piston structures, each piston structure comprising: a piston rod (11), a piston head (12) and a piston cylinder (13), wherein the piston head (12) is mounted on the top of the piston rod (11); A piston ring (121) is installed on the edge of the piston head (12). The piston ring (121) has a groove on its side. The piston rod (11) is installed inside the piston cylinder (13). The piston ring (121) is interference-fitted with the inner wall of the piston cylinder (13). Flexible conduits (2) are installed in pairs, and one piston structure connects one flexible conduit (2). Furthermore, the airbags (3) also appear in pairs, with a piston structure connected to one of the airbags (3) via a flexible conduit (2). The flexible conduit (2) is bonded to the top of the piston cylinder (13); The housing (8) of the mechanical device has a blind hole at the axis of the camshaft (42) and extends the camshaft (42) into the blind hole; The camshaft (42) deflects under the external force provided by the cam extension plate (41), causing the lower end (43) of the cam to rotate; A miniature displacement sensor is provided on the side of the cam extension plate (41); The contact point (82) between the end of the extension plate (411) of the cam and the housing of the mechanical device is an arc surface contact, and the radius of the arc surface is: the distance from the center of the cam shaft (42) to the uppermost point of the end of the extension plate on the two-dimensional airfoil section; One end of the connecting rod (5) is hinged to the lower end (43) of the cam; The inner extension plate (71) of the Gurney flap has a slot (711) for the Gurney flap. A sliding pin (83) is fixed to the mechanical device housing on the rear edge side. The sliding pin (83) passes through the slot (711) of the Gurney flap to restrain the movement of the Gurney flap. The inner extension plate (71) of the Gurney flap and the outer extension side (72) of the Gurney flap have pre-set ribs (73) on the inner side of the connection, and chamfers are made at the corresponding positions on the skin; The slot (711) of the Gurney flap mates with the sliding pin (83) on the outer casing of the mechanical device. The edges of the slot (711) of the Gurney flap and the sliding pin (83) should be chamfered. The neutral surface of the Gurney flap extension side (72) is reserved for a specified length longer than the outer side of the skin, and the specified length is one-hundredth of the chord length.

2. The apparatus according to claim 1, characterized in that, The part of the flexible conduit (2) exposed outside the blade is the flexible conduit extension side (21), wherein the flexible conduit extension side (21) is sealed to the bottom of the piston cylinder (13) to form a piston-flexible conduit connection (211). The flexible conduit (2) extends into the blade at the rear edge of the blade root. The part extending into the blade is the flexible conduit embedded side (22). The flexible conduit embedded side (22) is arranged radially along the blade. After passing through the opening (81) of the mechanical device housing, it is sealed and bonded to the airbag (3) to form the airbag-flexible conduit connection (221).

3. The apparatus according to claim 2, characterized in that, The cross-sectional area of ​​the conduit at the piston-flexible conduit connection (211) and the airbag-flexible conduit connection (221) both adopt a smooth transition design to avoid water hammer effect.

4. The apparatus according to claim 1, characterized in that, A pair of airbags (3) are divided into an upper airbag (31) and a lower airbag (32). The upper airbag (31) and the lower airbag (32) are both placed between the cam extension plate (41) and the mechanical device housing (8). The pressure difference between the upper airbag (31) and the lower airbag (32) acts on the cam extension plate (41), causing the cam (4) to rotate around the cam shaft (42), thereby driving the connecting rod (5) hinged to the lower end (43) of the cam to move. Each airbag (3) is made of a fully formed, sealing flexible material, and each airbag (3) is flat; the sealing flexible material is a material with an elastic modulus greater than or equal to 1.4 GPa.

5. The apparatus according to claim 1, characterized in that, A pair of piston actuators (1) are fixed on the rotor hub; An actuator fixing device (10) is pre-welded on the rotor hub. The shape of the mounting hole of the actuator fixing device (10) matches the fixed end of the piston actuator (1). After the fixed end of the piston actuator (1) is inserted into the mounting hole of the actuator fixing device (10), it fits tightly with the actuator fixing device (10). The fixing device (10) has openings to allow the flexible conduit (2) and the piston rod (11) to pass through respectively; A limit cover (101) is bolted to the edge of the mounting hole of the actuator fixing device (10), and the inner shape of the limit cover (101) matches the cross-section of the piston actuator (1).

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