A flexible folding wingtip structure based on asymmetric stiffness

Abstract

The present invention discloses a flexible folding wingtip structure based on asymmetric stiffness, relates to the technical field of wings, and comprises: a leading edge honeycomb, a trailing edge honeycomb, a folding drive unit and a wingtip, all of which have flexible deformation characteristics. The folding drive unit is arranged between the leading edge honeycomb and the trailing edge honeycomb, and the folding drive unit comprises a linear drive and a corrugated plate. Two ends of the linear drive are respectively hinged to two ends of the corrugated plate, the thickness of the crest surface of the corrugated plate is smaller than the thickness of the trough surface, and one end of the corrugated plate is connected with the wingtip. In the present invention, the thickness of the crest surface of the corrugated plate is smaller than the thickness of the trough surface, so that the corrugated plate itself has asymmetric stiffness. When the linear drive performs an elongation movement, the entire corrugated plate will fold upward, thereby playing a role in adjusting the angle of the wingtip. Compared with a multi-layer corrugated plate structure, not only the weight of the entire structure is reduced, but also the gap between the upper and lower layers of the corrugated plates is eliminated, which can effectively improve the flight performance of the aircraft.

Description

Technical Field

[0001] The invention relates to the technical field of wings, and in particular to a flexible folding wing tip structure based on asymmetric stiffness. Background Art

[0002] Traditional aircraft are designed based on a single fixed shape, so they can only be optimized for fixed design points, and their performance is significantly limited. In comparison, a morphing aircraft is an aircraft that can adaptively change its aerodynamic shape according to the needs of the flight mission. Morphing aircraft has many advantages such as improving aircraft performance and expanding the aircraft mission envelope. It has been one of the research hotspots in the aerospace field at home and abroad in recent years. Although the wingtip only occupies a small part of the wing, it has a great impact on the overall performance of the aircraft. Through folding and deformation of the wingtip, on the one hand, the aerodynamic shape of the wing can be adaptively adjusted to improve flight performance and reduce fuel consumption. Folding the wingtip on the ground can also reduce the apron space occupied by the wing. On the other hand, folding wingtips also have application potential such as controlling flight attitude and alleviating gust loads.

[0003] The existing flexible folding wingtip structure adopts a multi-layer corrugated plate structure, that is, the stiffness of the upper and lower layers of corrugated plates is inconsistent, so as to realize the folding of the wingtip under the action of driving force. However, the multi-corrugated plate structure will increase the structural mass, and there is a large gap between the upper and lower layers of corrugated plates, so the structure is prone to pressure instability, thereby reducing flight performance.

[0004] Therefore, people are in urgent need of a flexible folding wingtip structure based on asymmetric stiffness that can improve flight performance. Summary of the invention

[0005] The purpose of the present invention is to provide a flexible folding wingtip structure based on asymmetric stiffness to solve the problems existing in the above-mentioned prior art, and to achieve the purpose of improving flight performance by designing the asymmetric stiffness of a single-layer corrugated plate.

[0006] To achieve the above-mentioned purpose, the present invention provides the following solution: The present invention provides a flexible folding wingtip structure based on asymmetric stiffness, comprising a leading edge honeycomb, a trailing edge honeycomb, a folding drive unit and a wingtip, all of which have flexible deformation characteristics, wherein the folding drive unit is arranged between the leading edge honeycomb and the trailing edge honeycomb, the folding drive unit comprises a linear drive and a corrugated plate, the two ends of the linear drive are respectively hinged to the two ends of the corrugated plate, the thickness of the crest surface of the corrugated plate is less than the thickness of the trough surface, and one end of the corrugated plate is connected to the wingtip.

[0007] Preferably, the linear drive is arranged close to the trough surface of the corrugated plate.

[0008] Preferably, a cavity for arranging the linear actuator is provided in the middle of the corrugated plate, and the cavity passes through the corrugated plate from top to bottom.

[0009] Preferably, along the span direction of the wing, at least two of the folding drive units are sequentially arranged between the leading edge honeycomb and the trailing edge honeycomb, and adjacent folding drive units are connected by a connecting piece.

[0010] Preferably, the thickness of the connecting section between the crest surface and the trough surface of the corrugated plate changes gradually.

[0011] Preferably, the leading edge honeycomb and the trailing edge honeycomb both include a plurality of frames and a connecting structure, the plurality of frames are spaced apart along the wingspan direction and vertically arranged on the side of the corrugated plate, adjacent frames are connected by the connecting structure, and the connecting structure is corrugated.

[0012] Preferably, the frame, the connecting structure and the corrugated plate are integrally arranged.

[0013] Preferably, the frame, the connecting structure and the corrugated plate are made of nylon.

[0014] Compared with the prior art, the present invention mainly achieves the following technical effects:

[0015] The thickness of the crest surface of the corrugated plate is smaller than the thickness of the trough surface, so that the corrugated plate itself has asymmetric stiffness. When the linear drive performs an extension movement, the entire corrugated plate will fold upward, thereby adjusting the angle of the wingtip. Compared with the multi-layer corrugated plate structure, it not only reduces the weight of the overall structure, but also eliminates the gap between the upper and lower layers of corrugated plates, which can effectively improve the flight performance of the aircraft.

[0016] Compared with the prior art, other solutions of the present invention have achieved the following technical effects:

[0017] The linear drive is arranged close to the trough surface of the corrugated plate, which can provide an eccentric torque to drive the structure to fold, which is beneficial to reduce the force required to drive the corrugated plate to fold and reduce energy loss.

[0018] Multiple folding drive units can complete the large-angle folding of the overall structure by superimposing them at a small angle, avoiding the problem of excessive protrusion of the linear drive and damage to the aircraft skin when a single folding drive unit is folded at a large angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 A schematic diagram of the structure of a flying wing provided with a flexible folding wing tip structure based on asymmetric stiffness according to the present invention;

[0021] Figure 2 It is a schematic structural diagram of a flexible folding wing tip structure based on asymmetric stiffness of the present invention;

[0022] Figure 3 It is a structural schematic diagram of a folding drive unit of the present invention;

[0023] Figure 4 It is a schematic diagram of the structure after two folding drive units of the present invention are connected;

[0024] Figure 5 It is a schematic structural diagram of the leading edge honeycomb of the present invention;

[0025] Figure 6 It is a schematic diagram of the structure of the trailing edge honeycomb of the present invention;

[0026] Figure 7 It is a schematic diagram of the structure of the linear actuator of the present invention;

[0027] Figure 8 It is a structural schematic diagram of the honeycomb structure of the leading edge honeycomb and the trailing edge honeycomb of the present invention;

[0028] Fig. 9 The state diagram of the corrugated plate of the present invention before and after deformation;

[0029] Fig.10 It is a structural schematic diagram of the corrugated plate of the present invention;

[0030] Among them, 1. leading edge honeycomb; 2. trailing edge honeycomb; 3. folding drive unit; 4. linear drive; 5. corrugated plate; 6. connecting part; 7. connecting piece; 8. frame; 9. connecting structure; 10. main body section; 11. wing tip; 12. wing tip flexible folding structure. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The purpose of the present invention is to provide a flexible folding wingtip structure based on asymmetric stiffness to solve the problems existing in the prior art and to achieve the purpose of improving flight performance by designing the asymmetric stiffness of a single-layer corrugated plate.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Please refer to Figures 1 to 10 As shown, a flexible folding wingtip structure 12 based on asymmetric stiffness is provided, comprising a leading edge honeycomb 1, a trailing edge honeycomb 2, a folding drive unit 3 and a wingtip 11, all of which have flexible deformation characteristics. The folding drive unit 3 is arranged between the leading edge honeycomb 1 and the trailing edge honeycomb 2. The folding drive unit 3 comprises a linear drive 4 and a corrugated plate 5. The linear drive 4 can be an electric telescopic rod, a pneumatic telescopic rod or a hydraulic telescopic rod, etc. The two ends of the linear drive 4 are respectively hinged to the two ends of the corrugated plate 5. Specifically, additional connecting parts 6 are respectively arranged at the two ends of the corrugated plate 5, and the two ends of the linear drive 4 are respectively hinged to the connecting parts 6 at the two ends of the corrugated plate 5 through hinges; or when the corrugated plate 5 is manufactured, the end thereof is provided with a connecting part 6 in one piece. The linear actuator 4 is hinged to the connection part 6 through a hinge, and bolt connection holes are arranged on the additional connection parts 6 at both ends of the corrugated plate 5 or the integrally arranged connection parts 6. One end of the corrugated plate 5 is connected to the wing tip 11 through the connection part 6, and the connection part 6 at the other end is used to connect the main body of the flight wing. The thickness of the crest surface of the corrugated plate 5 is less than the thickness of the trough surface, so that the corrugated plate 5 itself has asymmetric stiffness. When the linear actuator 4 performs an extension movement, the entire corrugated plate 5 will fold toward the thinner side, thereby playing a role in adjusting the angle of the wing tip 11. Compared with the multi-layer corrugated plate structure, it not only reduces the weight of the overall structure, but also eliminates the gap between the upper and lower corrugated plates 5, which can effectively improve the flight performance of the aircraft.

[0035] Preferably, the thickness of the crest surface of the corrugated plate 5 is 1.5-3 times the thickness of the trough surface.

[0036] The linear drive 4 is arranged close to the trough surface of the corrugated plate 5, that is, the linear drive 4 is offset, which can provide an eccentric torque to drive the structure to fold, which is beneficial to reduce the force required to drive the corrugated plate 5 to fold and reduce energy loss.

[0037] Preferably, a cavity for setting the linear drive 4 is opened in the middle of the corrugated plate 5, and the cavity passes through the corrugated plate 5 from top to bottom. The cavity divides one corrugated plate 5 into two small corrugated plates 5 located on both sides of the linear drive 4, which is actually equivalent to setting a corrugated plate 5 on both sides of the linear drive 4. The cavity can not only minimize the damage to the skin caused by installation when the linear drive 4 is in action, but also the corrugated plates 5 on both sides provide a connection basis for the leading edge honeycomb 1 and the trailing edge honeycomb 2, avoiding the problem that when the linear drive 4 is set on one side of the corrugated plate 5, one side of the corrugated plate 5 will be occupied by the linear drive 4, resulting in only one side wall of the corrugated plate 5 being available for the leading edge honeycomb 1 or the trailing edge honeycomb 2 to be installed, and an additional flexible connection basis needs to be set for another honeycomb between the main section 10 of the wing and the wing tip 11.

[0038] When a single corrugated plate 5 is folded at a large angle, the linear drive 4 will be exposed and occupy the upper and lower side spaces, and a bow-shaped structure will be presented between the linear drive 4 and the corrugated plate 5. At this time, the linear drive 4 will cause damage to the skin. Therefore, along the wingspan direction of the wing, at least two folding drive units 3 are sequentially arranged between the leading edge honeycomb 1 and the trailing edge honeycomb 2, and the adjacent folding drive units 3 are connected by a connecting piece 7. Multiple folding drive units 3 can complete the large-angle folding of the overall structure by superimposing at a small angle, thereby avoiding the problem of excessive protrusion of the linear drive 4 and causing damage to the aircraft skin when a single folding drive unit 3 is folded at a large angle.

[0039] The connecting member 7 can be formed integrally with the corrugated plate 5 , and the connecting member 7 is provided on each of two adjacent corrugated plates 5 , and the two connecting members 7 are connected by bolts.

[0040] A plurality of folding drive units 3 may share one corrugated plate 5 , in which case the connecting member 7 is connected to the upper and lower sides of the corrugated plate 5 , and extends inward to form a mounting portion for the linear drive 4 to be mounted.

[0041] The fixed ends of the linear drivers 4 of two adjacent folding drive units 3 are arranged opposite to each other.

[0042] The thickness of the connection section between the wave crest surface and the wave trough surface of the corrugated plate 5 changes gradually, so as to avoid the problem that when the thickness of the connection section changes in steps, the folding stress is easily concentrated at the step, thereby reducing the service life.

[0043] The specific structure of the leading edge honeycomb 1 and the trailing edge honeycomb 2 includes a plurality of frames 8 and a connecting structure 9. The plurality of frames 8 are spaced apart along the wingspan direction and vertically arranged on the side of the corrugated plate 5. Adjacent frames 8 are connected by the connecting structure 9. The connecting structure 9 is corrugated to facilitate folding and deformation along with the corrugated plate 5.

[0044] In order to improve the structural strength, the frame 8, the connecting structure 9 and the corrugated plate 5 are integrally arranged.

[0045] The frame 8, the connecting structure 9 and the corrugated plate 5 are made of nylon and are formed by 3D printing.

[0046] The two ends of the corrugated plate 5 are respectively connected to the main section 10 and the wing tip 11 of the flying wing to form an integral wing.

[0047] The flexible folding wingtip structure 12 based on asymmetric stiffness needs to be provided with a skin on the outside during actual use. The skin can be selected from PDMS silicone film, which is made of PDMS silicone rubber and has all the properties of silicone. It can still maintain flexibility, elasticity, transparency and other characteristics within a wide temperature range. When bonding with the flexible folding wingtip structure 12 based on asymmetric stiffness, a bidirectional stretching mechanism is used for pre-stretching to reduce the wrinkles produced and meet the mechanical performance requirements required for deformation.

[0048] During actual use, the linear actuator 4 is controlled to extend, and the corrugated plate 5 is folded toward the thinner wave crest surface, thereby driving the wing tip 11 to fold; when reset is required, the linear actuator 4 is controlled to contract.

[0049] Adaptive changes made according to actual needs are all within the protection scope of the present invention.

[0050] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

[0051] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A flexible folding wing tip structure based on asymmetric stiffness, characterized in that: It includes a leading edge honeycomb, a trailing edge honeycomb, a folding drive unit and a wing tip, all of which have flexible deformation characteristics. The folding drive unit is arranged between the leading edge honeycomb and the trailing edge honeycomb. The folding drive unit includes a linear drive and a corrugated plate. The two ends of the linear drive are respectively hinged to the two ends of the corrugated plate. The thickness of the crest surface of the corrugated plate is less than the thickness of the trough surface. One end of the corrugated plate is connected to the wing tip.

2. The flexible folding wing tip structure based on asymmetric stiffness according to claim 1, characterized in that: The linear drive is arranged close to the trough surface of the corrugated plate.

3. The flexible folding wing tip structure based on asymmetric stiffness according to claim 1, characterized in that: A cavity for arranging the linear drive is provided in the middle of the corrugated plate, and the cavity passes through the corrugated plate from top to bottom.

4. The flexible folding wing tip structure based on asymmetric stiffness according to claim 1, characterized in that: Along the wingspan direction of the wing, at least two folding drive units are sequentially arranged between the leading edge honeycomb and the trailing edge honeycomb, and adjacent folding drive units are connected by a connecting piece.

5. The flexible folding wing tip structure based on asymmetric stiffness according to claim 1, characterized in that: The thickness of the connecting section between the wave crest surface and the wave trough surface of the corrugated plate changes gradually.

6. The flexible folding wing tip structure based on asymmetric stiffness according to claim 1, characterized in that: The leading edge honeycomb and the trailing edge honeycomb both include a plurality of frames and a connecting structure. The plurality of frames are spaced apart along the wingspan direction and vertically arranged on the side of the corrugated plate. Adjacent frames are connected by the connecting structure, and the connecting structure is corrugated.

7. The flexible folding wing tip structure based on asymmetric stiffness according to claim 6, characterized in that: The frame, the connecting structure and the corrugated plate are integrally arranged.

8. The flexible folding wing tip structure based on asymmetric stiffness according to claim 7, characterized in that: The frame, the connecting structure and the corrugated plate are all made of nylon.

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