Strain energy structure undercarriage for unmanned aerial vehicle and manufacturing method of strain energy structure undercarriage

Abstract

The invention discloses a strain energy structure undercarriage for an unmanned aerial vehicle and a manufacturing method of the strain energy structure undercarriage. The two ends of the undercarriage body are bent downwards to form buffer sections, a filling part is formed in the middle of the undercarriage body, the buffer sections are of a cavity structure, and core materials are arranged in the filling part. A skin is arranged on the periphery of the undercarriage main body, the skin is a composite skin, and the skin comprises an upper skin and a lower skin which are attached to each other; the inner part of the skin is covered with an adhesive film layer, the adhesive film layer comprises an upper adhesive film layer covering the upper skin and a lower adhesive film layer covering the lower skin, the peripheries of the upper adhesive film layer and the lower adhesive film layer are mutually bonded, and the adhesive film layer is bonded with the core material to fix the core material. The buffer section and the filling part are arranged on the undercarriage main body, so that the rigidity of the undercarriage is ensured, and meanwhile, the lightweight design is realized; the undercarriage main body uses the skin, the structural advantages of a composite material are utilized, damping and energy absorption are achieved through elastic deformation of the composite material, and the damping capacity is high; and the undercarriage main body adopts an integrated design, so that the number of parts is reduced, the manufacturing cost is reduced, and the assembly and maintenance period is shortened.

Description

Technical Field

[0001] The invention relates to the field of aviation vehicles, in particular to a strain energy structure landing gear for an unmanned aerial vehicle and a manufacturing method thereof. Background Art

[0002] As an important branch of aircraft, drones have developed rapidly in recent years. They have been widely promoted in air cargo, disaster relief, agricultural operations, fire fighting assistance, etc., especially cargo drones, which have become a major component of the low-altitude economy. The landing gear is an important structural component of the drone, which is of great significance to the drone's fuselage structure and flight safety during the drone's ground parking, take-off and landing.

[0003] The existing drone landing gear is divided into active shock absorbing structure and passive shock absorbing structure. The active shock absorbing structure drone landing gear is equipped with multiple adjustment mechanisms and recovery mechanisms, which can be adaptively adjusted during the lifting process through the adjustment mechanism sliding wheel; it is designed with a control module. Although it can be actively adjusted, it has a complex structure, numerous systems, multiple failure points, and heavy weight. Another drone landing gear adopts an adjustable installation and fixing mechanism, which can adjust the landing gear according to the actual size of the drone, so as to adapt to the installation and use of drones of different sizes, improve the adaptability of the device, and cooperate with the buffer protection mechanism. Although it can ensure the stability of the drone landing and effectively avoid the drone from tipping over and colliding due to vibration and other reasons, it belongs to a split structure and needs to be connected multiple times. There are problems such as heavy weight and low reliability. Another drone landing gear is designed with a receiving slot, and a first spring is provided inside the receiving slot. The reaction force of the spring is innovatively used for shock absorption. Although it saves unnecessary operation steps, the convenient disassembly mechanism also makes it easy for users to store it, but the spring structure has disadvantages such as heavy weight. There is also a buffer support structure, which includes a cylinder, a plurality of partitions are slidably arranged in the cylinder, and a filling space is formed between adjacent partitions. The filling space is filled with crushing energy absorbing materials, and shock absorption is achieved through the energy absorbing materials; although the prior art solves the problem that near-space solar drones are not suitable for oil-gas mixed buffers, and the use of elastic materials to absorb energy will cause the drone to bounce, it has the disadvantages of high manufacturing requirements and high costs. Another new type of integrated landing gear structure for drones, the two ends of the front bend pipe are respectively connected to the two adjacent skids through the front joint; the rear bend pipe is set in an inverted U shape, and the two ends of the rear bend pipe are respectively connected to the two adjacent skids through the rear joint. The landing gear is installed at the bottom of the drone through the front bend pipe and the rear bend pipe. Although the landing gear is an integrated landing gear structure, the number of parts used is small, the installation method is simple, and the bend pipe is integrated, which greatly improves the structural strength of the parts, enhances the life of the landing gear, and has the advantages of a skid-shaped landing gear, but does not have a shock absorption effect. In the field of composite landing gear, the design schemes are all three-dimensional woven structures and manufactured or assembled using composite pipe fittings. The landing gear manufactured using three-dimensional weaving has the advantages of excellent impact resistance, high interlayer strength, and is not prone to delamination failure. However, it has the disadvantages of complicated manufacturing process, long three-dimensional weaving process cycle, and low efficiency. When using composite pipe fittings structure, the connection of the pipe fittings can easily become the starting point of structural failure, and multiple parts assembly is required. The assembly accuracy is difficult to guarantee and the manufacturing cost is high.

[0004] Therefore, it is urgent to provide a solution for a drone landing gear. Summary of the invention

[0005] In order to solve the above problems, the technical solution of the present invention provides a strain energy structure landing gear for unmanned aerial vehicles and a manufacturing method thereof, which realizes a lightweight design while ensuring the stiffness of the landing gear.

[0006] According to a first aspect of the technical solution of the present invention, there is provided a strain energy structure landing gear for a drone, comprising: a landing gear body;

[0007] Both ends of the landing gear body are bent downward to form a buffer section, the ends are in contact with the ground to support the landing gear body, and a filling part is formed in the middle. The buffer section is a cavity structure, and a core material is provided inside the filling part;

[0008] The outer periphery of the landing gear body is a skin, and the skin is a composite material skin, and the skin includes an upper skin and a lower skin that are attached to each other;

[0009] The inner part of the skin is covered with a film layer, the film layer includes an upper film layer covering the upper skin and a lower film layer covering the lower skin, the upper film layer and the lower film layer are bonded to each other on all sides, and the film layer is bonded to the core material to fix the core material;

[0010] When subjected to external force, the buffer section undergoes elastic deformation.

[0011] In the above solution, protective sleeves are sleeved on both ends of the landing gear body, and the protective sleeves are sleeved on the ground contact surface of the landing gear body.

[0012] In the above solution, the core material includes a foam core material.

[0013] In the above solution, the skin is a reinforced fiber tissue and / or a unidirectional tape.

[0014] In the above solution, the landing gear body is provided with a connecting hole, and the landing gear is fixed to the drone through the connecting hole.

[0015] According to a second aspect of the technical solution of the present invention, there is provided a method for manufacturing a strain energy structure landing gear for a UAV, which is used to manufacture any of the strain energy structure landing gears for a UAV as described above, comprising:

[0016] S1. Fix the upper skin on the assembly tooling for positioning;

[0017] S2, fixing the processed core material on the adhesive film layer;

[0018] S3, laminating and bonding the lower skin and the lower adhesive film;

[0019] S4, placing the upper skin, the core material and the upper film layer, and the lower skin and the lower film layer into a vacuum bag for assembly;

[0020] S5. Place the assembled structure into an autoclave for secondary bonding.

[0021] In the above solution, the upper skin and the lower skin are made of carbon fiber prepreg.

[0022] In the above solution, the core material includes PMI foam core material with a density of 100kg / m3.

[0023] In the above solution, the upper adhesive film layer and the lower adhesive film layer include J133 epoxy adhesive film, and the thickness of the adhesive film is 0.1 to 0.2 mm.

[0024] In the above scheme, the secondary bonding temperature is 80℃±5℃, the insulation time is 2h, and the pressure is 0.2±0.02MPa.

[0025] Beneficial effects of the present invention:

[0026] The present invention discloses a strain energy structure landing gear for unmanned aerial vehicles and a manufacturing method thereof. By arranging a buffer section and a filling part on the landing gear body, the rigidity of the landing gear is ensured while achieving a lightweight design. The landing gear body uses a skin, utilizes the structural advantages of the composite material, and absorbs shock and energy through the elastic deformation of the composite material, so the shock absorbing ability is strong. In addition, the landing gear body adopts an integrated design, which reduces the number of parts, reduces the manufacturing cost, and shortens the assembly and maintenance cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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 or the description of the prior art 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 the structures shown in these drawings without paying creative work.

[0028] Figure 1 This is a schematic diagram of the overall structure of the strain energy structure landing gear for a UAV provided in Example 1 of the present invention;

[0029] Figure 2 A cross-sectional view of a filling portion of a strain energy structure landing gear for a UAV provided in Example 1 of the present invention;

[0030] Figure 3 A cross-sectional view of the buffer section of the strain energy structure landing gear for a UAV provided in Example 1 of the present invention.

[0031] Among them: landing gear body -1; protective cover -2; core material -3; skin -4; film layer -5; connection hole -6.

[0032] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0033] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0034] The terms "first", "second", etc. in the specification and claims of the present disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein, for example.

[0035] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0036] Multiple includes two or more.

[0037] It should be understood that the term "and / or" used in this disclosure is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone.

[0038] Example 1

[0039] like Figure 1 , Figure 2 and Figure 3 As shown, an embodiment of the technical solution of the present invention provides a strain energy structure landing gear for unmanned aerial vehicles, including: a landing gear body 1; the two ends of the landing gear body 1 are bent downward to form a buffer section, the end portions are in contact with the ground for supporting the landing gear body 1, and a filling portion is formed in the middle, the buffer section is a cavity structure, and a core material 3 is arranged inside the filling portion; the outer periphery of the landing gear body 1 is a skin 4, the skin 4 is a composite material skin, and the skin 4 includes an upper skin and a lower skin that fit each other; the inside of the skin 4 is covered with a film layer 5, the film layer 5 includes an upper film layer covering the upper skin and a lower film layer covering the lower skin, the upper film layer and the lower film layer are bonded to each other on all sides, and the film layer 5 is bonded to the core material 3 to fix the core material 3; when subjected to external force, the buffer section produces elastic deformation. The buffer section is an axisymmetric structure. The buffer section is perpendicular to the ground or tilted outward to achieve a better support effect.

[0040] The present invention ensures the rigidity of the landing gear while achieving a lightweight design by arranging a buffer section and a filling part on the landing gear body 1; the landing gear body 1 uses a skin 4, utilizes the structural advantages of the composite material, and absorbs shock and energy through the elastic deformation of the composite material, and has a strong shock absorption capacity; and the landing gear body 1 adopts an integrated design, which reduces the number of parts, reduces the manufacturing cost, and shortens the assembly and maintenance cycle.

[0041] In this embodiment, protective sleeves 2 are preferably provided at both ends of the landing gear body 1, and the protective sleeves 2 are provided on the ground contact surface of the landing gear body 1. The protective sleeves 2 can protect both ends of the landing gear body 1 and prevent the landing gear body 1 from excessive wear.

[0042] In this embodiment, the core material 3 preferably includes a foam core material 3. Specifically, a PMI foam core material 3 is used, and the density is 100 kg / m 3 The structure of the core material 3 is calculated based on the area to be filled.

[0043] In this embodiment, the skin 4 is preferably a reinforced fiber tissue and / or a unidirectional tape. Further, it is made of carbon fiber prepreg, specifically, T800 high-strength fiber reinforced epoxy resin prepreg, with a single layer thickness of 0.1 mm, the thickness of the skin 4 is designed to be 0.7 mm, and the ply is designed in the order of 45°, -45°, 0°, 90°, 0°, -45° and 45° along the fiber direction. The multi-directional ply can withstand loads in all directions, thereby improving the rigidity of the landing gear body 1.

[0044] In this embodiment, the landing gear body 1 is preferably provided with a connecting hole 6, and the landing gear is fixed to the UAV through the connecting hole 6, so that the UAV is buffered during the take-off or landing process.

[0045] In this embodiment, the skin 4 includes an upper skin and a lower skin, and the film layer 5 includes an upper film layer and a lower film layer. During production, the upper skin and the lower skin are pressed together through a mold, the upper film layer and the lower film layer stick the upper skin and the lower skin together, and the core material 3 is stuck and fixed.

[0046] Example 2

[0047] An embodiment of the technical solution of the present invention provides a method for manufacturing a strain energy structure landing gear for a UAV, which is used to manufacture the strain energy structure landing gear for a UAV as described in any of the above items, comprising:

[0048] S1. Fix the upper skin on the assembly tooling for positioning;

[0049] S2, fixing the processed core material 3 on the adhesive film layer;

[0050] S3, laminating and bonding the lower skin and the lower adhesive film;

[0051] S4, putting the upper skin, the core material 3 and the upper film layer, the lower skin and the lower film layer into a vacuum bag for assembly;

[0052] S5. Place the assembled structure into an autoclave for secondary bonding.

[0053] The upper and lower skins are made of carbon fiber prepreg. Specifically, T800 high-strength fiber reinforced epoxy resin prepreg is used, the single layer thickness is 0.1mm, the thickness of skin 4 is designed to be 0.7mm, and the layers are designed in the order of 45°, -45°, 0°, 90°, 0°, -45° and 45° along the fiber direction. The size of the upper and lower skins is 1200mm long and 40mm wide.

[0054] The core material 3 includes a PMI foam core material 3 with a density of 100 kg / m 3 The core material 3 can be processed in 5 straight sections. The initial thickness of the core material 3 blank is 12 mm. The blank is fixed on the machine tool and processed by the machine tool. The processing speed is set at 1 m / min and the milling cutter speed is 1800 rpm.

[0055] The adhesive film layer 5 includes a J133 epoxy adhesive film, and the thickness of the adhesive film is 0.1-0.2 mm, specifically 0.15 mm.

[0056] In step S1, the upper skin is first cured and formed, and then fixed on an assembly fixture for positioning. The surface to be bonded to the upper adhesive film layer is polished with 80# sandpaper. After polishing, it is cleaned with acetone and dried naturally.

[0057] In step S2, the surface of the processed core material 3 is cleaned, the designed size and position are installed to ensure that the length of the buffer section meets 60±2 mm, and the core material 3 is fixed to the upper glue film layer.

[0058] In step S3, the surface of the lower skin to be bonded to the lower adhesive film layer is polished with 80# sandpaper. After polishing, it is cleaned with acetone, dried naturally, and assembled on the lower adhesive film layer.

[0059] In step S4, a vacuum bag is first made and solidified by the temperature and pressure of the autoclave, the heating rate of the autoclave is guaranteed to be ≤2°C / min, the holding time is 2h, and the maximum pressure is 0.5MPa. Then, the upper skin, the core material 3 and the upper film layer, the lower skin and the lower film layer are assembled under the condition of holding the pressure for 30min and the vacuum degree ≤-0.095MPa.

[0060] In step S5, the secondary bonding temperature is 80°C±5°C, the insulation time is 2h, and the pressure is 0.2±0.02MPa.

[0061] In this embodiment, the protective sleeve 2 is manufactured by casting and molding a silicone rubber material. First, the A and B components of the silicone rubber are evenly mixed in a mass ratio of 5:1, and stirred in a stirrer at a speed of 50 rpm. After stirring for 30 minutes, the mixed silicone rubber is poured into a mold, and the mold is demolded after standing at room temperature for 12 hours to obtain the protective sleeve 2.

[0062] In this embodiment, the connection holes 6 on the landing gear body 1 are made on a machine tool, the diameter of the connection holes 6 is 5±0.1 mm, the number of the connection holes 6 is 4, and the processing speed is 2000 rpm.

[0063] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0064] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0065] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of the present invention.

[0066] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A strain energy structure landing gear for an unmanned aerial vehicle, characterized in that: include: Landing gear body; Both ends of the landing gear body are bent downward to form a buffer section, the ends are in contact with the ground to support the landing gear body, and a filling part is formed in the middle. The buffer section is a cavity structure, and a core material is provided inside the filling part; The outer periphery of the landing gear body is a skin, the skin is a composite material skin, and the skin includes an upper skin and a lower skin that are bonded to each other; The inner part of the skin is covered with a film layer, the film layer includes an upper film layer covering the upper skin and a lower film layer covering the lower skin, the upper film layer and the lower film layer are bonded to each other on all sides, and the film layer is bonded to the core material to fix the core material; When subjected to external force, the buffer section undergoes elastic deformation.

2. The strain energy structure landing gear for UAV according to claim 1, characterized in that: Protective sleeves are sleeved on both ends of the landing gear body, and the protective sleeves are sleeved on the ground contact surface of the landing gear body.

3. The strain energy structure landing gear for UAV according to claim 1, characterized in that: The core material comprises a foam core material.

4. The strain energy structure landing gear for UAV according to claim 1, characterized in that: The skin is a reinforced fiber structure and / or a unidirectional tape.

5. The strain energy structure landing gear for UAV according to claim 1, characterized in that: The landing gear body is provided with a connecting hole, and the landing gear is fixed to the UAV through the connecting hole.

6. A method for manufacturing a strain energy structure landing gear for an unmanned aerial vehicle, characterized in that: The strain energy structure landing gear for a UAV according to any one of claims 1 to 5 comprises: S1. Fix the upper skin on the assembly tooling for positioning; S2, fixing the processed core material on the adhesive film layer; S3, laminating and bonding the lower skin and the lower adhesive film; S4, putting the upper skin, the core material and the upper film layer, and the lower skin and the lower film layer into a vacuum bag for assembly; S5. Place the assembled structure into an autoclave for secondary bonding.

7. The method for manufacturing the strain energy structure landing gear for a UAV according to claim 6, characterized in that: The upper skin and the lower skin are made of carbon fiber prepreg.

8. The method for manufacturing the strain energy structure landing gear for a UAV according to claim 6, characterized in that: The core material includes PMI foam core material with a density of 100kg / m 3 .

9. The method for manufacturing the strain energy structure landing gear for a UAV according to claim 6, characterized in that: The upper adhesive film layer and the lower adhesive film layer include J133 epoxy adhesive film, and the thickness of the adhesive film is 0.1-0.2 mm.

10. The method for manufacturing a strain energy structure landing gear for a UAV according to claim 6, characterized in that: The secondary bonding temperature is 80℃±5℃, the insulation time is 2h, and the pressure is 0.2±0.02MPa.

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