A wingtip folding drive mechanism based on a shape memory alloy torsion tube

Abstract

The present invention discloses a wingtip folding drive mechanism based on a shape memory alloy torsion tube, which relates to the technical field of aircraft and includes: a drive unit, the drive unit includes a bias torsion spring and a shape memory alloy torsion tube arranged between the wing main body and the wingtip; one end of the shape memory alloy torsion tube is fixedly connected to the wing main body, and the other end is circumferentially clamped with a flange. The flange is fixedly connected to one end of a sleeve, the sleeve is sleeved on the shape memory alloy torsion tube, and the sleeve is in clearance fit with the shape memory alloy torsion tube. The sleeve is fixedly connected to the wingtip, the bias torsion spring is sleeved on the sleeve, and one end of the bias torsion spring is fixedly connected to the wing main body and the other end is fixedly connected to the wingtip; a braking unit, the braking unit is used to brake the rotation of the flange; a temperature control unit, the temperature control unit is used to change the ambient temperature of the shape memory alloy torsion tube. The structure of the present invention is simple, and it can realize the drive of wingtip folding under the conditions of smaller space and smaller weight.

Description

Technical Field

[0001] The present invention relates to the technical field of aircraft, and particularly to a wingtip folding drive mechanism based on a shape memory alloy torsion tube. Background Art

[0002] With the development of intelligent materials and structures, various concepts of intelligent material actuators have been continuously proposed. In variable aircraft, there are also many intelligent structure actuators in the drive schemes for achieving variations. Wingtip folding is also a current application hotspot in the field of variable aircraft. By controlling the wingtip folding angle, the induced drag during flight can be effectively reduced. In addition, the wingtip folding indirectly controls the wingspan, enabling the aircraft to adapt to more flight environments. At the same time, reducing the wingtip folding on the ground can also improve space utilization and enable more aircraft to be parked.

[0003] In the limited space of the wing, when designing and arranging the wingtip active folding mechanism, for shape memory materials, there are also relatively rich types of available actuators. Such as shape memory alloy wires, shape memory alloy plates, shape memory alloy torsion springs, etc. The above several driving elements are all realized based on the shape memory characteristics of the material and all conform to the characteristics of high energy density of shape memory alloys. However, to realize the driving process of wingtip folding, torque needs to be provided to the hinge mechanism at the wingtip connection position. For the application method of shape memory alloy wires, it can be achieved by an integrated method to obtain as much effective length as possible, thereby generating a sufficient driving stroke. In addition, a transmission mechanism is also required to convert the motion form of the shape memory alloy wire into a driving force that can be used for wingtip folding. Similarly, a similar design is required for shape memory alloy plates. The shape memory alloy torsion spring also has the function of directly outputting torque and can also be integrated at the hinge position for direct drive control. However, the structure of the shape memory alloy torsion spring is complex, and it is more difficult to establish a constitutive model suitable for wingtip folding control. The stress state of the material during torsion is also more difficult to determine compared to the pure shear state of the tubular structure.

[0004] Existing wingtip folding drive devices (such as shape memory alloy wires, shape memory alloy plates, and shape memory alloy torsion springs) can control the deflection angle of the wingtip, but they have the following deficiencies: First, the shape memory alloy wire requires a sufficient effective length to ensure a sufficient driving stroke, and a motion conversion structure is also needed for motion form conversion; the application of the shape memory alloy plate in a variable wing is mostly seen in applications such as variable camber and variable thickness. When used as a wingtip folding drive element, its motion form conversion method is more complex than that of the wire; although the shape memory alloy torsion spring can also be directly used as a power element for torque output, the complexity of its structure, the processing difficulty of the material, and the selection of heating and cooling methods during subsequent applications all increase the complexity of design and application. Summary of the Invention

[0005] The purpose of the present invention is to provide a wingtip folding drive mechanism based on a shape memory alloy torsion tube to solve the problems existing in the above-mentioned prior art, simplify the wingtip folding drive mechanism, and realize the drive of wingtip folding under the conditions of a smaller space and a smaller weight.

[0006] To achieve the above purpose, the present invention provides the following solutions:

[0007] The present invention provides a wingtip folding drive mechanism based on a shape memory alloy torsion tube, including:

[0008] A drive unit, the drive unit includes a bias torsion spring and a shape memory alloy torsion tube arranged between the wing main body and the wingtip. The shape memory alloy torsion tube is a straight tube, and the axis of the shape memory alloy is parallel to the axis of the rotation axis when the wingtip folds; one end of the shape memory alloy torsion tube is fixedly connected to the wing main body, and the other end is circumferentially clamped with a flange. The flange is fixedly connected to one end of a sleeve. The sleeve is sleeved on the shape memory alloy torsion tube, and the sleeve is in clearance fit with the shape memory alloy torsion tube. The sleeve is fixedly connected to the wingtip. The bias torsion spring is sleeved on the sleeve, and one end of the bias torsion spring is fixedly connected to the wing main body and the other end is fixedly connected to the wingtip;

[0009] Brake unit, the brake unit includes a fixed support, a brake pad, a thrust bearing, a first support spring, an electromagnet, and a friction plate fixedly sleeved on the flange. The first support spring and the thrust bearing are both arranged in the fixed support. One end of the first support spring abuts against the fixed support, and the other end abuts against one end of the thrust bearing. One end of the flange extends into the fixed support, and the other end of the thrust bearing contacts the end of the flange extending into the fixed support. A plurality of parallel struts are circumferentially arranged at one end of the brake pad. A guide hole is provided on the outer wall of the fixed support corresponding to each strut. The strut is slidably matched with the corresponding guide hole. A second support spring is sleeved on each strut. One end of the second support spring is connected to the fixed support, and the other end is connected to the brake pad. The friction plate is located between the thrust bearing and the brake pad. The brake pad is annular, and the inner diameter of the brake pad is smaller than the outer diameter of the friction plate. The electromagnet is fixedly arranged at one end of the fixed support away from the brake pad;

[0010] Temperature control unit, the temperature control unit includes an air duct and an air outlet pipe. The air outlet pipe is arranged in the shape memory alloy torsion tube, and a plurality of support rings are sleeved on the air outlet pipe. The outer wall of the support ring is slidably matched with the inner wall of the shape memory alloy torsion tube; A plurality of air outlet holes facing the shape memory alloy torsion tube are uniformly distributed on the pipe wall of the air outlet pipe. One end of the air outlet pipe is open and the other end is closed. The open end of the air outlet pipe is communicated with one end of the air duct, and the other end of the air duct is communicated with the aircraft air source. The aircraft air source is used to inject high-temperature gas or low-temperature gas into the air duct and the air outlet pipe.

[0011] Preferably, it further includes a first connecting piece, a first fixing ring, a second fixing ring, a snap ring, and a second connecting piece. The first connecting piece is detachably connected to the wing main body. The first fixing ring is circumferentially clamped to the end of the shape memory alloy torsion tube away from the flange, and the first fixing ring is detachably connected to the first connecting piece. The snap ring is sleeved on the sleeve and is circumferentially clamped to the sleeve. The snap ring is detachably connected to the second connecting piece. The second connecting piece is detachably connected to the wing tip; The second fixing ring is detachably connected to the first connecting piece and is rotatably sleeved on the sleeve; One end of the biasing torsion spring is fixedly connected to the first connecting piece, and the other end is fixedly connected to the second connecting piece.

[0012] Preferably, the second connecting piece is integrally formed with the wing tip beam of the wing tip.

[0013] Preferably, a first hexagonal column is provided at one end of the shape memory alloy torsion tube close to the flange. The first hexagonal column is coaxial with the shape memory alloy torsion tube. Six limiting rods are respectively provided on six faces of the flange corresponding to the first hexagonal column, and the limiting rods are in sliding fit with the corresponding faces.

[0014] Preferably, a second hexagonal column is provided at one end of the shape memory alloy torsion tube close to the first fixing ring. The first fixing ring is sleeved on the second hexagonal column, and the first fixing ring is circumferentially clamped with the second hexagonal column.

[0015] Preferably, the air guide pipe is perpendicular to the air outlet pipe, and the air guide pipe is communicated with the air outlet pipe through a right-angle elbow. The air guide pipe passes through the wing main body, and the air guide pipe is fixedly connected with the wing main body through a plurality of supporting members.

[0016] Preferably, a bearing is used as the support ring.

[0017] Preferably, an angle control unit is further included. The angle control unit includes a controller, a first gyroscope fixedly arranged in the wing main body, a second gyroscope fixedly arranged at the wing tip, and a plurality of temperature sensors arranged on the shape memory alloy torsion tube. The controller adopts the central control system of the aircraft. The first gyroscope, the second gyroscope, and the temperature sensors are respectively connected with the controller in a signal manner. The controller can calculate the current folding angle of the wing tip according to the feedback values of the first gyroscope and the second gyroscope, and obtain the current temperature of the shape memory alloy torsion tube according to the feedback number of the temperature sensor. The controller can judge the direction in which the shape memory alloy torsion tube needs to twist according to the current folding angle of the wing tip and the folding angle that the wing tip needs to reach, and judge whether to introduce high-temperature gas or low-temperature gas into the shape memory alloy torsion tube according to the direction in which the shape memory alloy torsion tube needs to twist and the current temperature of the shape memory alloy torsion tube. And the controller can control the aircraft air source to introduce high-temperature or low-temperature gas into the shape memory alloy torsion tube through the air guide pipe and the air outlet pipe until the shape memory alloy torsion tube drives the wing tip to rotate to the required folding angle.

[0018] The present invention has achieved the following technical effects compared with the prior art:

[0019] The structure of the wing tip folding drive mechanism based on the shape memory alloy torsion tube of the present invention is simple, and the shape memory alloy torsion tube has a large energy density and a driving stroke that can meet the needs of wing tip folding, and can realize the drive of wing tip folding under the conditions of a smaller space and a smaller weight.

[0020] Furthermore, during the forward torsion of the shape memory alloy torsion tube in the present invention, the biasing torsion spring stores a part of the energy, which can provide sufficient torque output for the reverse recovery process of the shape memory alloy torsion tube.

[0021] Furthermore, the braking unit in the present invention can, after the wing tip is driven to a specified angle, energize the electromagnet to clamp the friction plate on the flange with the brake pad and the fixed support, thereby braking the rotation of the wing tip.

[0022] Furthermore, in the present invention, the temperature control unit can control the ambient temperature of the shape memory alloy torsion tube, and further control the phase change process of the shape memory alloy torsion tube, control the shape memory alloy torsion tube to generate forward or reverse torsion. The forward torsion is the heating torque output process, and the reverse torsion is the cooling recovery process; when it is recognized that the flight environment of the aircraft changes, according to the wing tip deflection angle most suitable for the current flight environment, control the ambient temperature of the shape memory alloy torsion tube to keep the torsion tube in a certain degree of phase change, and combine with the braking unit to realize continuous control of the torsion angle, so as to adapt to the current flight environment and obtain higher flight benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 FIG. is a schematic structural diagram of a wing tip folding drive mechanism based on a shape memory alloy torsion tube of the present invention;

[0025] Figure 2 FIG. is a schematic structural diagram of a wing tip folding drive mechanism based on a shape memory alloy torsion tube of the present invention;

[0026] Figure 3 FIG. is an exploded view of a wing tip folding drive mechanism based on a shape memory alloy torsion tube of the present invention;

[0027] Figure 4 FIG. is a schematic structural diagram of a shape memory alloy torsion tube in the present invention;

[0028] Figure 5 FIG. is a partial schematic structural diagram of a wing tip folding drive mechanism based on a shape memory alloy torsion tube of the present invention;

[0029] Figure 6 FIG. is a schematic structural diagram of the braking unit in the present invention;

[0030] Figure 7 Explosion diagram of the braking unit in the present invention;

[0031] Figure 8 Partial structural schematic diagram of the temperature control unit in the present invention;

[0032] Wherein:

[0033] 1. Wing main body;

[0034] 2. Wing beam;

[0035] 3. Wing tip;

[0036] 4. Air duct;

[0037] 5. First bracket;

[0038] 6. First fixing ring;

[0039] 7. Second connecting piece;

[0040] 8. Second fixing ring;

[0041] 9. Braking unit; 901. Fixed support; 902. Electromagnet mounting seat; 903. Connecting piece; 904. Brake pad; 905. Second support spring; 906. Flange; 907. Support rod; 908. Thrust bearing; 909. First support spring; 910. Friction plate; 911. Guide hole;

[0042] 10. Snap ring;

[0043] 11. First connecting piece;

[0044] 12. Sleeve;

[0045] 13. Offset torsion spring;

[0046] 14. Shape memory alloy torsion tube;

[0047] 15. Air outlet pipe; 151. Air outlet hole;

[0048] 16. First gyroscope;

[0049] 17. Second gyroscope;

[0050] 18. Temperature sensor;

[0051] 19. Support ring. Detailed implementation manners

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0053] The object of the present invention is to provide a wingtip folding drive mechanism based on a shape memory alloy torsion tube to solve the problems existing in the above-mentioned prior art, simplify the wingtip folding drive mechanism, and realize the drive of wingtip folding under the conditions of a smaller space and a smaller weight.

[0054] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0055] As Figures 1 to 8 shown, this embodiment provides a wingtip folding drive mechanism based on a shape memory alloy torsion tube, including:

[0056] A drive unit, the drive unit includes a biasing torsion spring 13 and a shape memory alloy torsion tube 14 disposed between the wing main body 1 and the wingtip 3. The shape memory alloy torsion tube 14 is a straight tube, and the axis of the shape memory alloy is parallel to the axis of the rotation axis when the wingtip 3 folds. One end of the shape memory alloy torsion tube 14 is fixedly connected to the wing main body 1, and the other end is circumferentially clamped with the flange 906. The flange 906 is fixedly connected or circumferentially clamped to one end of the sleeve 12. When the flange 906 is circumferentially clamped with the sleeve 12, the flange can axially move relative to the sleeve 12. The sleeve 12 is sleeved on the shape memory alloy torsion tube 14, and the sleeve 12 and the shape memory alloy torsion tube 14 are in clearance fit. The sleeve 12 is fixedly connected to the wingtip 3. The biasing torsion spring 13 is sleeved on the sleeve 12, and one end of the biasing torsion spring 13 is fixedly connected to the wing main body 1 and the other end is fixedly connected to the wingtip 3;

[0057] The braking unit 9, the braking unit 9 includes a fixed support 901, a brake pad 904, a thrust bearing 908, a first support spring 909, an electromagnet, and a friction plate 910 fixedly sleeved on a flange 906. The first support spring 909 and the thrust bearing 908 are both arranged inside the fixed support 901. One end of the first support spring 909 abuts against the limiting step at the first end of the fixed support 901, and the other end abuts against one end of the thrust bearing 908. One end of the flange 906 extends into the fixed support 901 from the second end of the fixed support 901, and the other end of the thrust bearing 908 contacts the end of the flange 906 extending into the fixed support 901. A plurality of parallel struts 907 are circumferentially arranged at one end of the brake pad 904. A guide hole 911 is provided on the outer wall of the fixed support 901 corresponding to each strut 907. The strut 907 is slidably matched with the corresponding guide hole 911. A second support spring 905 is sleeved on each strut 907. One end of the second support spring 905 is connected to the fixed support 901, and the other end is connected to the brake pad 904. The friction plate 910 is located between the thrust bearing 908 and the brake pad 904. Both the brake pad 904 and the friction plate 910 are annular. The inner diameter of the brake pad 904 is smaller than the outer diameter of the friction plate 910, and the outer diameter of the friction plate 910 is larger than the inner diameter of the fixed support 901. There are multiple electromagnets, and they are all fixedly arranged at the end of the fixed support 901 away from the brake pad 904;

[0058] The temperature control unit, the temperature control unit includes an air guide pipe 4 and an air outlet pipe 15. The air outlet pipe 15 is arranged through a shape memory alloy torsion tube 14, and a plurality of support rings 19 are sleeved on the air outlet pipe 15. The outer wall of the support ring 19 is slidably matched with the inner wall of the shape memory alloy torsion tube 14; A plurality of air outlet holes 151 facing the shape memory alloy torsion tube 14 are evenly distributed on the pipe wall of the air outlet pipe 15. One end of the air outlet pipe 15 is open and the other end is closed. The open end of the air outlet pipe 15 is communicated with one end of the air guide pipe 4, and the other end of the air guide pipe 4 is communicated with the aircraft air source. The aircraft air source is used to inject high-temperature gas or low-temperature gas into the air guide pipe 4 and the air outlet pipe 15. Two first brackets 5 are arranged inside the wing main body 1. The air guide pipe 4 is connected to the first brackets 5, and the support and fixation of the air guide pipe 4 are realized through the first brackets 5.

[0059] The working principle of the braking unit 9 in this embodiment is as follows:

[0060] When there is no braking effect, the electromagnet is not energized. Due to the action of the first support spring 909, the friction plate 910 on the flange 906 does not contact the fixed support 901. At the same time, the second support spring 905 on the brake plate 904 also prevents the brake plate 904 from contacting the friction plate 910 on the flange 906. Also, because of the existence of the thrust bearing 908, the first support spring 909 does not affect the rotational movement of the flange 906, thus ensuring the normal operation of the entire mechanism. When a braking effect is generated, the electromagnet is energized. The magnetic field generated by the electromagnet will attract the brake plate 904 to move towards the fixed support 901, so that both the brake plate 904 and the fixed support 901 overcome the supporting force of the spring to clamp the friction plate 910 on the flange 906, thereby generating a braking effect. When the power is cut off, the electromagnet loses its magnetism, and the brake plate 904 and the flange 906 will separate due to the existence of the first support spring 909 and the second support spring 905 and continue to maintain the moving state.

[0061] In an alternative embodiment of the present embodiment, preferably, a plurality of electromagnet mounting seats 902 are provided on the side wall of the fixed support 901. The electromagnet mounting seats 902 correspond to the electromagnets one by one, and the electromagnets are installed in the corresponding electromagnet mounting seats 902.

[0062] The working principle of the wingtip folding drive mechanism based on the shape memory alloy torsion tube in this embodiment is as follows:

[0063] When it is necessary to fold the wingtip 3 forward, first ensure that the electromagnet in the braking unit 9 is not energized. Then, high-temperature gas is injected into the guide pipe 4 and the air outlet pipe 15 through the aircraft air source. The high-temperature gas blows towards the shape memory alloy torsion tube 14 through the plurality of air outlet holes 151 on the air outlet pipe 15, causing the ambient temperature of the shape memory alloy torsion tube 14 to rise. When the shape memory alloy torsion tube 14 is heated, it will undergo a forward twist, driving the flange 906 to rotate. The flange 906 drives the sleeve 12 to rotate, and the sleeve 12 drives the wingtip 3 to rotate, thereby realizing the folding of the wingtip 3. When the folding angle of the wingtip 3 reaches the preset angle, the electromagnet in the braking unit 9 is turned on, so that the electromagnet attracts the brake plate 904 to move towards the fixed support 901. The brake plate 904 overcomes the elastic force of the second support spring 905 and cooperates with the fixed support 901 to clamp the friction plate 910 on the flange 906, thereby preventing the flange 906 from continuing to rotate, and thus realizing the braking of the folding of the wingtip 3.

[0064] When the reverse folding of the wing tip 3 is required, first ensure that the electromagnet in the braking unit 9 is de-energized, and then inject low-temperature gas into the guide pipe 4 and the air outlet pipe 15 through the aircraft air source. The low-temperature gas blows towards the shape memory alloy torsion tube 14 through the multiple air outlet holes 151 on the air outlet pipe 15, causing the ambient temperature of the shape memory alloy torsion tube 14 to decrease. When the shape memory alloy torsion tube 14 is cooled, it will undergo reverse torsion (i.e., the recovery process), driving the flange 906 to rotate in the reverse direction. The flange 906 drives the sleeve 12 to rotate, and the sleeve 12 drives the wing tip 3 to rotate, thereby realizing the reverse folding of the wing tip 3. Similarly, when the folding angle of the wing tip 3 reaches the preset angle, turn on the electromagnet in the braking unit 9, so that the electromagnet adsorbs the brake pad 904 to move towards the fixed support 901. The brake pad 904 overcomes the elastic force of the second support spring 905 and cooperates with the fixed support 901 to clamp the friction plate 910 on the flange 906, thereby preventing the flange 906 from continuing to rotate, and further realizing the braking of the folding of the wing tip 3.

[0065] In an alternative embodiment of the present embodiment, preferably, it further includes a first connecting member 11, a first fixing ring 6, a second fixing ring 8, a snap ring 10 and a second connecting member 7. The first connecting member 11 is detachably connected to the wing body 1. The first fixing ring 6 is circumferentially clamped to the end of the shape memory alloy torsion tube 14 away from the flange 906, and the first fixing ring 6 is detachably connected to the first connecting member 11. The snap ring 10 is sleeved on the sleeve 12 and is circumferentially clamped to the sleeve 12. The snap ring 10 is detachably connected to the second connecting member 7, and the second connecting member 7 is detachably connected to the wing tip 3. The second fixing ring 8 is detachably connected to the first connecting member 11 and is rotatably sleeved on the sleeve 12. One end of the biasing torsion spring 13 is fixedly connected to the first connecting member 11, and the other end is fixedly connected to the second connecting member 7. A connecting piece 903 is fixedly provided on the side of the fixed support 901, and the connecting piece 903 is fixedly connected to the first connecting member 11.

[0066] A wing beam 2 is further provided in the wing body 1, and the function of the wing beam 2 is to support the wing body 1.

[0067] In an alternative embodiment of the present embodiment, preferably, the second connecting member 7 and the wing tip beam of the wing tip 3 are integrally formed, that is, the second connecting member 7 integrates the function of the wing tip beam, making the structure of the wing tip folding drive mechanism based on the shape memory alloy torsion tube in this embodiment simpler.

[0068] In an alternative embodiment of the present embodiment, preferably, a first hexagonal column is provided at one end of the shape memory alloy torsion tube 14 close to the flange 906. The first hexagonal column is coaxial with the shape memory alloy torsion tube 14. Six limiting rods are respectively provided on six faces of the flange 906 corresponding to the first hexagonal column, and the limiting rods are slidably engaged with the corresponding faces. The circumferential clamping of the flange 906 and the shape memory alloy torsion tube 14 is realized through the sliding engagement of the limiting rods and the corresponding faces. It should be noted that the means for realizing the circumferential clamping of the flange 906 and the shape memory alloy torsion tube 14 is not limited to the above-described solution of this embodiment, and in practical applications, the circumferential clamping of the flange 906 and the shape memory alloy torsion tube 14 can also be realized by other means.

[0069] In an alternative embodiment of the present embodiment, preferably, a second hexagonal column is provided at one end of the shape memory alloy torsion tube 14 close to the first fixing ring 6. The first fixing ring 6 is sleeved on the second hexagonal column, and the first fixing ring 6 is circumferentially clamped with the second hexagonal column. It should be noted that the means for realizing the circumferential clamping of the first fixing ring 6 and the shape memory alloy torsion tube 14 is not limited to the above-described solution of this embodiment, and in practical applications, the circumferential clamping of the first fixing ring 6 and the shape memory alloy torsion tube 14 can also be realized by other means.

[0070] In an alternative embodiment of the present embodiment, preferably, the air duct 4 is perpendicular to the air outlet pipe 15, and the air duct 4 is communicated with the air outlet pipe 15 through a right-angle elbow. The air duct 4 passes through the wing main body 1, and the air duct 4 is fixedly connected to the wing main body 1 through a plurality of support members. The support members are provided as hollow to reduce the influence on other structures inside the wing while ensuring the stability of the input air flow.

[0071] In an alternative embodiment of the present embodiment, preferably, a bearing is used as the support ring 19, and the outer ring of the bearing is fixedly connected to the inner wall of the shape memory alloy torsion tube 14, and the inner ring of the bearing is fixedly connected to the outer wall of the air outlet pipe 15.

[0072] In an alternative embodiment of the present embodiment, preferably, an angle control unit is further included. The angle control unit includes a controller, a first gyroscope 16 fixedly arranged in the wing main body 1, a second gyroscope 17 fixedly arranged at the wing tip 3, and a plurality of temperature sensors 18 arranged on the shape memory alloy torsion tube 14. The controller uses the central control system of the aircraft. The first gyroscope 16, the second gyroscope 17, and the temperature sensors 18 are respectively connected to the controller in signal. The controller can calculate the current folding angle of the wing tip 3 according to the feedback values of the first gyroscope 16 and the second gyroscope 17, and obtain the current temperature of the shape memory alloy torsion tube 14 according to the feedback values of the temperature sensors 18. The aircraft can automatically identify the current flight environment and obtain the folding angle required for the wing tip 3 of the aircraft. The controller can judge the direction in which the shape memory alloy torsion tube 14 needs to be twisted according to the current folding angle of the wing tip 3 and the folding angle that the wing tip 3 needs to reach, and judge whether to introduce high-temperature gas or low-temperature gas into the shape memory alloy torsion tube 14 according to the direction in which the shape memory alloy torsion tube 14 needs to be twisted and the current temperature of the shape memory alloy torsion tube 14. Moreover, the controller can control the aircraft gas source to introduce high-temperature or low-temperature gas into the shape memory alloy torsion tube 14 through the air duct 4 and the air outlet pipe 15 until the shape memory alloy torsion tube 14 drives the wing tip 3 to rotate to the required folding angle. It should be noted that when the wing tip 3 reaches the required rotation angle, the controller controls the electromagnet in the braking unit 9 to be energized. The magnetic field generated by the electromagnet will adsorb the brake pad 904 to move towards the fixed support 901, so as to clamp the friction plate 910 on the flange 906 together with the fixed support 901 against the supporting force of the spring, thereby generating a braking effect and keeping the wing tip 3 at the current angle, thus completing the rotation of the wing tip 3 to the set angle.

[0073] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "top", "bottom", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0074] In the present invention, specific examples are used to elaborate the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A wingtip folding drive mechanism based on a shape memory alloy torsion tube, characterized in that Comprising: A drive unit, the drive unit includes a biasing torsion spring and a shape memory alloy torsion tube disposed between the wing body and the wing tip. The shape memory alloy torsion tube is a straight tube, and the axial direction of the shape memory alloy is parallel to the axial direction of the rotation axis when the wing tip is folded; one end of the shape memory alloy torsion tube is fixedly connected to the wing body, and the other end is circumferentially clamped to a flange. The flange is fixedly connected to one end of a sleeve. The sleeve is sleeved on the shape memory alloy torsion tube, and the sleeve is in clearance fit with the shape memory alloy torsion tube. The sleeve is fixedly connected to the wing tip. The biasing torsion spring is sleeved on the sleeve, and one end of the biasing torsion spring is fixedly connected to the wing body and the other end is fixedly connected to the wing tip; A braking unit, the braking unit includes a fixed support, a brake pad, a thrust bearing, a first support spring, an electromagnet, and a friction plate fixedly sleeved on the flange. The first support spring and the thrust bearing are both disposed within the fixed support. One end of the first support spring abuts against the fixed support and the other end abuts against one end of the thrust bearing. One end of the flange extends into the fixed support, and the other end of the thrust bearing contacts the end of the flange extending into the fixed support. One end of the brake pad is circumferentially provided with a plurality of parallel struts. The outer wall of the fixed support is provided with a guiding hole corresponding to each strut. The strut is in sliding fit with the corresponding guiding hole. A second support spring is sleeved on each strut. One end of the second support spring is connected to the fixed support and the other end is connected to the brake pad. The friction plate is located between the thrust bearing and the brake pad. The brake pad is annular, and the inner diameter of the brake pad is smaller than the outer diameter of the friction plate. The electromagnet is fixedly provided at one end of the fixed support away from the brake pad; A temperature control unit, the temperature control unit includes an air duct and an air outlet pipe. The air outlet pipe is disposed through the shape memory alloy torsion tube, and a plurality of support rings are sleeved on the air outlet pipe. The outer wall of the support ring is in sliding fit with the inner wall of the shape memory alloy torsion tube; a plurality of air outlet holes facing the shape memory alloy torsion tube are uniformly distributed on the pipe wall of the air outlet pipe. One end of the air outlet pipe is open and the other end is closed. The open end of the air outlet pipe is communicated with one end of the air duct, and the other end of the air duct is communicated with the aircraft air source. The aircraft air source is used to inject high-temperature gas or low-temperature gas into the air duct and the air outlet pipe.

2. The wingtip folding drive mechanism based on a shape memory alloy torsion tube according to claim 1, wherein: It further includes a first connecting member, a first fixing ring, a second fixing ring, a snap ring and a second connecting member. The first connecting member is detachably connected to the wing main body. The first fixing ring is circumferentially clamped to the end of the shape memory alloy torsion tube away from the flange, and the first fixing ring is detachably connected to the first connecting member. The snap ring is sleeved on the sleeve and is circumferentially clamped to the sleeve. The snap ring is detachably connected to the second connecting member, and the second connecting member is detachably connected to the wing tip. The second fixing ring is detachably connected to the first connecting member and is rotatably sleeved on the sleeve. One end of the biasing torsion spring is fixedly connected to the first connecting member, and the other end is fixedly connected to the second connecting member.

3. The wingtip folding drive mechanism based on a shape memory alloy torsion tube according to claim 2, wherein: The second connecting member is integrally formed with the wing tip beam of the wing tip.

4. The wingtip folding drive mechanism based on a shape memory alloy torsion tube according to claim 1, characterized in that: A first hexagonal column is provided at one end of the shape memory alloy torsion tube close to the flange. The first hexagonal column is coaxial with the shape memory alloy torsion tube. Six limiting rods are respectively provided on six faces of the flange corresponding to the first hexagonal column, and the limiting rods are slidably matched with the corresponding faces.

5. The wingtip folding drive mechanism based on a shape memory alloy torsion tube according to claim 2, characterized in that: A second hexagonal column is provided at one end of the shape memory alloy torsion tube close to the first fixing ring. The first fixing ring is sleeved on the second hexagonal column, and the first fixing ring is circumferentially clamped to the second hexagonal column.

6. The wingtip folding drive mechanism based on a shape memory alloy torsion tube according to claim 1, characterized in that: The air guide pipe is perpendicular to the air outlet pipe, and the air guide pipe is communicated with the air outlet pipe through a right-angle elbow. The air guide pipe passes through the wing main body, and the air guide pipe is fixedly connected to the wing main body through a plurality of support members.

7. The wingtip folding drive mechanism based on a shape memory alloy torsion tube according to claim 1, characterized in that: A bearing is used as the support ring.

8. The wingtip folding drive mechanism based on a shape memory alloy torsion tube according to claim 1, characterized in that: It further includes an angle control unit. The angle control unit includes a controller, a first gyroscope fixed in the wing main body, a second gyroscope fixed in the wing tip and a plurality of temperature sensors arranged on the shape memory alloy torsion tube. The controller uses the central control system of the aircraft. The first gyroscope, the second gyroscope and the temperature sensors are respectively connected to the controller in a signal manner. The controller can calculate the current folding angle of the wing tip according to the feedback values of the first gyroscope and the second gyroscope, and obtain the current temperature of the shape memory alloy torsion tube according to the feedback number of the temperature sensor. The controller can judge the direction in which the shape memory alloy torsion tube needs to be twisted according to the current folding angle of the wing tip and the folding angle that the wing tip needs to reach, and judge whether to introduce high-temperature gas or low-temperature gas into the shape memory alloy torsion tube according to the direction in which the shape memory alloy torsion tube needs to be twisted and the current temperature of the shape memory alloy torsion tube. Moreover, the controller can control the aircraft air source to introduce high-temperature or low-temperature gas into the shape memory alloy torsion tube through the air guide pipe and the air outlet pipe until the shape memory alloy torsion tube drives the wing tip to rotate to the required folding angle.

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