Composite material force bearing cavity structure of unmanned aerial vehicle and forming method

Abstract

The invention discloses an unmanned aerial vehicle composite material force bearing cavity structure and a forming method. The method comprises the steps that carbon fiber prepreg is laid on the outer surface of a mandrel mold, the mandrel mold is covered, an opening for taking out the mandrel mold is reserved, and after the carbon fiber prepreg is laid, the mandrel mold is taken out from the opening; the mandrel die is taken out from the opening to obtain a preformed body to bear the shape of the cavity structure, the preformed body is placed in a cavity of the lower die of the forming die, the upper die and the lower die of the forming die are combined through a positioning guide column and then connected and fixed through a fastening bolt hole, and integral curing forming is conducted through the die pressing technology. According to the invention, the silica gel core shaft mold is adopted, so that the core shaft mold can be conveniently taken out from the preformed body, the paving operation difficulty of the carbon fiber prepreg is greatly reduced, and the forming process is simplified; and integral curing forming is performed through a mold pressing process, the product curing forming time is short, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-rotor UAVs, and in particular to a composite material load-bearing cavity structure of a UAV and a molding method thereof. Background Art

[0002] A multi-rotor drone is an aerial drone with three or more rotor axes. Due to its small size, relatively simple structure, flexible control, and ability to carry a variety of devices, it is widely used in military, police, agriculture, forestry, water conservancy, electricity, firefighting, exploration and mapping and other industries.

[0003] The structural subsystems of a multi-rotor drone include the chassis, arms, legs, and gimbal. The chassis utilizes a load-bearing cavity structure to connect the chassis, enhance structural rigidity, withstand certain mounting loads, optimize wiring layout, and reduce wear. Currently, load-bearing cavity structures produced using traditional injection molding processes increase weight while increasing strength, while reducing weight reduces strength, making it difficult to balance structural stability and endurance. Summary of the Invention

[0004] To this end, the technical problem to be solved by the present invention is to provide a composite material load-bearing cavity structure for a UAV that can take into account both weight and strength.

[0005] In order to solve the above problems, the present invention provides a composite material load-bearing cavity structure for a UAV, comprising:

[0006] A shell, the shell being composed of an upper end surface, a lower end surface, and side surfaces, wherein the upper end surface and the lower end surface of the shell are connected through the side surfaces to form a load-bearing cavity;

[0007] A plurality of support arms are arranged on the side surface and communicated with the load-bearing cavity.

[0008] Furthermore, the number of the supporting arms is the same as the number of the UAV rotor shafts.

[0009] Furthermore, there are eight supporting arms, and the eight supporting arms are evenly distributed on the side surface.

[0010] Furthermore, the shell is a hollow cylinder.

[0011] Furthermore, a reserved opening for taking out the core shaft mold is provided on the upper end surface.

[0012] Furthermore, the support arm is a straight cylindrical tube for connecting to the UAV frame.

[0013] In addition, the present invention also provides a method for forming a composite material load-bearing cavity structure of a UAV, comprising:

[0014] Making the core shaft mold: Based on the inner surface of the load-bearing cavity structure, a silicone rubber core shaft mold with the same shape as the load-bearing cavity structure is designed and made;

[0015] Making a preform: laying carbon fiber prepreg on the outer surface of the mandrel mold, completely covering the mandrel mold, and leaving an opening for removing the mandrel mold. After laying the carbon fiber prepreg, remove the mandrel mold from the opening to obtain a preform;

[0016] Making the forming mold: Design the inner cavity surface of the upper and lower molds of the forming mold based on the outer surface of the load-bearing cavity structure;

[0017] Curing: Place the preform into the cavity of the lower mold of the forming mold, use the positioning guide pins to combine the upper and lower molds of the forming mold, and then connect and fix them through the fastening bolt holes, and use the molding process to solidify and form them as a whole.

[0018] Furthermore, the interior of the core shaft mold is a hollow structure, and the outer surface of the core shaft mold corresponds to and fits with the inner surface of the load-bearing cavity structure.

[0019] Furthermore, the process of making the preform specifically includes:

[0020] Lay the carbon fiber prepreg on the side, arm surface and upper and lower end surfaces of the core shaft mold;

[0021] The carbon fiber prepreg on the side of the mandrel mold is divided into 8 groups per layer, and is laid on the side areas of the mandrel mold on both sides of the support arm surface, and the prepreg is laid to the upper and lower end surfaces;

[0022] The carbon fiber prepreg on the mandrel mold arm surface is divided into 8 groups per layer, which are laid around the mandrel mold arm surface respectively, and the prepreg is overlapped to the side surface and the upper and lower end surfaces;

[0023] The carbon fiber prepreg on the lower end surface of the mandrel mold is cut into a circle the size of the lower end surface of the mandrel mold, and the whole is laid on the lower end surface of the mandrel mold, and the circumferential edge and the prepreg lapped to the lower end surface overlap;

[0024] The carbon fiber prepreg on the upper end surface of the mandrel mold is retained. On the basis of the prepreg on the side and arm surface overlapping to the upper end surface, prepreg of appropriate size is manually cut to fill the incomplete coverage;

[0025] Finally, when laying the carbon fiber prepreg on the outer surface of the core shaft mold, an opening for removing the core shaft mold is reserved at the center of the upper end surface of the core shaft mold. After the laying of the carbon fiber prepreg is completed, the core shaft mold is removed from the opening to obtain a preform.

[0026] Furthermore, the preform is placed in the cavity of the lower mold of the forming mold and the mold is closed. It is then pressed by a hot press, and the mold cavity is pressure-limited to control the temperature so that the preform is solidified and formed; then a cold press is used for molding, and the mold cavity is pressure-limited to cool the preform.

[0027] Compared with the existing technology, the present invention uses carbon fiber reinforced composite materials, lays the preform on the core shaft mold, and then puts it into the inner cavity of the metal forming mold, and adopts the molding process to solidify and mold it in one piece; the silicone core shaft mold of the present invention is easy to take out from the preform, which greatly reduces the difficulty of laying the carbon fiber prepreg and simplifies the molding process; the molding mold of the present invention adopts an upper and lower mold combination, and the product shape and size are accurate and consistent. Moreover, through the molding process of integral solidification, the product solidification molding time is short, and the production efficiency is improved. The present invention can improve the mechanical properties of the drone, reduce the weight, increase the endurance, and extend the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0029] Figure 1 is a schematic diagram of the load-bearing cavity structure of the present invention;

[0030] Figure 2 Schematic diagram of the mandrel mold of the present invention;

[0031] Figure 3 Schematic diagram of the lower mold of the molding die of the present invention;

[0032] Figure 4 Schematic diagram of the upper mold of the forming mold of the present invention.

[0033] Explanation of the marks in the figure: 10—shell; 20—support arm; 30—mandrel mold; 40—forming mold; 11—upper end face; 12—lower end face; 13—side face; 31—mandrel mold side face; 32—mandrel mold support arm face; 33—mandrel mold upper end face; 41—forming mold lower mold; 42—forming mold upper mold; 43—air inlet; 44—positioning guide pin; 45—fastening bolt hole; 46—parting line. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0036] It should also be understood that the terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0037] It should be further understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0038] See Figure 1 As shown, Figure 1 This is a schematic diagram of the load-bearing cavity structure of the present invention. This embodiment provides a composite load-bearing cavity structure for a drone, comprising a housing 10 and a plurality of arms 20. The housing 10 is a hollow cylinder, and the arms 20 are straight tubes. The arms 20 are used to connect to the drone frame. The number and placement of the arms 20 correspond to the rotor shafts of the drone. In this embodiment, the number of arms 20 is preferably eight.

[0039] The shell 10 is composed of an upper end surface 11, a lower end surface 12 and a side surface 13, wherein the upper end surface 11 and the lower end surface 12 of the shell 10 are connected through the side surface 13 to form a load-bearing cavity; the support arm 20 is arranged on the side surface 13 and is connected to the load-bearing cavity.

[0040] like Figure 2 As shown, Figure 2 This is a schematic diagram of the core shaft mold of the present invention. In this embodiment, the core shaft mold 30 is a reference Figure 1 The silicone rubber core shaft mold of the load-bearing cavity structure is designed and manufactured based on the inner surface of the load-bearing cavity structure and has the same shape as the load-bearing cavity structure.

[0041] The core shaft mold 30 is a hollow silicone rubber cavity composed of the core shaft mold upper end surface 33, the core shaft mold side surface 31 and the core shaft mold support arm surface 32. Its outer surface corresponds to and fits the inner surface of the load-bearing cavity structure.

[0042] The core shaft mold 30 is made of silicone rubber, which can be reduced in size when subjected to force, making it easy to take out or put in a smaller space.

[0043] like Figure 3 、 Figure 4 As shown, Figure 3 Schematic diagram of the lower mold of the molding die of the present invention; Figure 4 Schematic diagram of the upper mold of the molding die of the present invention. In this embodiment, the molding die 40 includes a lower molding die 41 and an upper molding die 42.

[0044] The lower mold 41 of the forming mold is provided with an air inlet 43, a fastening bolt hole 45 and a parting line 46; the upper mold 42 of the forming mold is provided with a corresponding air inlet 43, a positioning guide column 44, a fastening bolt hole 45 and a parting line 46; when the lower mold 41 of the forming mold and the upper mold 42 of the forming mold are correspondingly closed, they can be used to form a load-bearing cavity structure.

[0045] The air inlet 43 of the lower mold 41 of the forming mold corresponds to the air inlet 43 of the upper mold 42 of the forming mold to form an air inlet, and the upper mold and the lower mold are aligned through the positioning guide column 44. The fastening bolt hole 45 of the upper mold corresponds to the fastening bolt hole 45 of the lower mold and the mold joining line 46 of the upper and lower molds corresponds. The mold joining line 46 is designed to be an acute angle, which can be used to quickly break off scraps to ensure the product outline.

[0046] Another embodiment of the present invention further provides a method for forming a composite material load-bearing cavity structure of a UAV, which specifically includes the following steps:

[0047] Making a mandrel mold: the mandrel mold is as follows Figure 2 As shown, it is made of silicone rubber, has a hollow structure inside, and has the same shape as the load-bearing cavity structure, and can become smaller when subjected to pressure; the outer surface of the core shaft mold corresponds to the inner surface of the load-bearing cavity structure.

[0048] In this embodiment, the core shaft mold is designed and manufactured based on the inner surface of the load-bearing cavity structure.

[0049] Making a preform: laying carbon fiber prepreg on the outer surface of the mandrel mold, covering the mandrel mold, and leaving an opening for removing the mandrel mold. After laying the carbon fiber prepreg, remove the mandrel mold from the opening to obtain a preform;

[0050] The process of making a preform specifically includes:

[0051] Lay the carbon fiber prepreg on the side, arm surface and upper and lower end surfaces of the core shaft mold;

[0052] The carbon fiber prepreg on the side of the mandrel mold is divided into 8 groups per layer and laid on the side areas of the mandrel mold on both sides of the support arm surface, with the prepreg lapped to the upper and lower end surfaces;

[0053] The carbon fiber prepreg on the mandrel mold arm surface is divided into 8 groups per layer and laid around the mandrel mold arm surface. The prepreg is overlapped to the side and upper and lower end surfaces.

[0054] The carbon fiber prepreg on the lower end surface of the mandrel mold is cut into a circle the size of the lower end surface of the mandrel mold and laid on the lower end surface of the mandrel mold as a whole, with the circumferential edge and the side of the prepreg overlapping the lower end surface;

[0055] The carbon fiber prepreg on the upper end face of the mandrel mold is retained. On the basis of the prepreg on the side and arm surface overlapping to the upper end face, prepreg of appropriate size is manually cut to fill the incomplete coverage.

[0056] Finally, when laying the carbon fiber prepreg on the outer surface of the core shaft mold, an opening for removing the core shaft mold is reserved in the center of the upper end surface of the core shaft mold. After the carbon fiber prepreg is laid, it is easy to remove it from the opening due to the silicone rubber material characteristics of the core shaft mold to obtain a preform of the carbon fiber prepreg.

[0057] In this embodiment, the load-bearing cavity structure is preformed by paving on the surface of the core shaft mold, and the silicone core shaft mold is easy to remove from the preformed body, which greatly reduces the difficulty of the paving operation of the carbon fiber prepreg and simplifies the molding process.

[0058] It should be noted that the carbon fiber prepreg in this embodiment is a high-performance carbon fiber reinforced fast-curing epoxy resin prepreg, corresponding to the laminate structure. Carbon fiber prepreg has the advantages of light weight, high strength, long service life, strong designability, and good rigidity.

[0059] Making a forming mold: the forming mold is as follows Figure 3 、 4 As shown, it is made of metal and includes upper and lower molds, and corresponding air inlets and parting lines are formed after the upper and lower molds are closed.

[0060] The molding die is designed with the outer surface of the load-bearing cavity structure as the reference for designing the inner cavity surface of the upper and lower molds of the molding die. Moreover, the molding die in this embodiment adopts an upper and lower mold combination, and the product shape and size are accurate and consistent.

[0061] Curing: Place the preform into the cavity of the lower mold of the forming mold, use the positioning guide pins to combine the upper and lower molds of the forming mold, and then connect and fix them through the fastening bolt holes, and use the molding process to solidify and form them as a whole.

[0062] A cylindrical silicone block needs to be inserted into the support arm position of the preform for support, and a through hole is reserved in the center of the silicone block in one of the arms; a special-shaped air bag needs to be placed inside the shell of the preform, and the air bag is connected to the air pipe through the through hole reserved in the center of the silicone block.

[0063] This embodiment is integrally cured and formed through a molding process, and the product curing and molding time is short, and production efficiency is improved. The above process can improve the mechanical properties of the drone, reduce weight, increase flight endurance, and extend service life.

[0064] The above detailed description of the specific embodiments of the present invention is intended to be illustrative only, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications or substitutions of the present invention are also within the scope of the present invention. Therefore, equivalent changes, modifications, and improvements made without departing from the spirit and scope of the present invention should be included within the scope of the present invention.

Claims

1. A composite material load-bearing cavity structure for an unmanned aerial vehicle, characterized in that: include: A shell (10), the shell (10) being composed of an upper end surface (11), a lower end surface (12) and a side surface (13), wherein the upper end surface (11) and the lower end surface (12) of the shell (10) are connected via the side surface (13) to form a load-bearing cavity; A plurality of support arms (20) are provided on the side surface (13) and are in communication with the load-bearing cavity.

2. The composite load-bearing cavity structure of the UAV according to claim 1, characterized in that: The number of the supporting arms (20) is the same as the number of the UAV rotor shafts.

3. The composite load-bearing cavity structure of the UAV according to claim 2, characterized in that: There are eight support arms (20), and the eight support arms (20) are evenly distributed on the side surface (13).

4. The composite load-bearing cavity structure of the UAV according to claim 1, characterized in that: The housing (10) is a hollow cylinder.

5. The composite load-bearing cavity structure of the UAV according to claim 1, characterized in that: The upper end surface (11) is provided with a reserved opening for taking out the core shaft mold.

6. The composite load-bearing cavity structure of the UAV according to claim 1, characterized in that: The support arm (20) is a straight cylindrical tube used for connecting to the UAV frame.

7. A method for forming a composite material load-bearing cavity structure of an unmanned aerial vehicle, characterized in that: include: Making the core shaft mold: Based on the inner surface of the load-bearing cavity structure, a silicone rubber core shaft mold with the same shape as the load-bearing cavity structure is designed and made; Making a preform: laying carbon fiber prepreg on the outer surface of the mandrel mold, covering the mandrel mold, and leaving an opening for removing the mandrel mold. After laying the carbon fiber prepreg, remove the mandrel mold from the opening to obtain a preform; Making the forming mold: Design the inner cavity surface of the upper and lower molds of the forming mold based on the outer surface of the load-bearing cavity structure; Curing: Place the preform into the cavity of the lower mold of the forming mold, use the positioning guide pins to combine the upper and lower molds of the forming mold, and then connect and fix them through the fastening bolt holes, and use the molding process to solidify and form them as a whole.

8. The molding method according to claim 7, wherein: The interior of the core shaft mold is a hollow structure, and the outer surface of the core shaft mold corresponds to and fits with the inner surface of the load-bearing cavity structure.

9. The molding method according to claim 8, wherein: The process of making the preform specifically includes: Lay the carbon fiber prepreg on the side, arm surface and upper and lower end surfaces of the core shaft mold; The carbon fiber prepreg on the side of the mandrel mold is divided into 8 groups per layer, and is laid on the side areas of the mandrel mold on both sides of the support arm surface, and the prepreg is laid to the upper and lower end surfaces; The carbon fiber prepreg on the support arm surface of the mandrel mold is divided into 8 groups per layer, which are laid around the support arm surface of the mandrel mold, and the prepreg is overlapped to the side surface and the upper and lower end surfaces; The carbon fiber prepreg on the lower end surface of the mandrel mold is cut into a circle the size of the lower end surface of the mandrel mold, and the whole is laid on the lower end surface of the mandrel mold, and the circumferential edge and the prepreg lapped to the lower end surface overlap; The carbon fiber prepreg on the upper end surface of the mandrel mold is retained. On the basis of the prepreg on the side and arm surface overlapping to the upper end surface, prepreg of appropriate size is manually cut to fill the incomplete coverage; Finally, when laying the carbon fiber prepreg on the outer surface of the core shaft mold, an opening for removing the core shaft mold is reserved at the center of the upper end surface of the core shaft mold. After the laying of the carbon fiber prepreg is completed, the core shaft mold is removed from the opening to obtain a preform.

10. The molding method according to claim 8, wherein: After the preform is placed in the cavity of the lower mold of the forming mold and the mold is closed, it is pressed by a hot press. The pressure in the mold cavity is limited to control the temperature so that the preform is solidified and formed; then a cold press is used for molding. The pressure in the mold cavity is limited to cool the preform.

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