A method for forming a UAV main wing beam composite flange

Abstract

The application discloses a forming method of a main wing beam composite material flange of a unmanned aerial vehicle, and relates to the technical field of unmanned aerial vehicle manufacturing. The forming method comprises the following steps: fixing an end round corner at a right-angle flange corner, wherein the shape of the end round corner is matched with that of the right-angle flange corner, and the outer side surface of the end round corner is a circular arc surface; laying a flange prepreg on a flange prepreg laying area, the circular arc surface of the end round corner and the inner side wall of a flange mold to form a flange prepreg layer; and setting the end round corner at the right-angle flange corner of the flange mold to change the right-angle turning of the original flange prepreg root corner, so that the flange prepreg can be smoothly and gently turned along the circular arc surface, and the hollow drum phenomenon is not prone to occur. The silica gel mold can transmit the vacuum pressure to the flange prepreg corner area through the silica gel mold round corner which is matched in shape with the circular arc surface, so that the solidification pressure of the flange prepreg corner area is ensured, and internal quality defects are avoided.

Description

Technical Field

[0001] This invention relates to the field of unmanned aerial vehicle (UAV) manufacturing technology, and in particular to a method for forming a composite material flange for the main wing spars of a UAV. Background Technology

[0002] The main wing spars of a drone are the primary load-bearing components of the drone's wing structure, bearing most of the lift and overload during flight.

[0003] The composite material flanges for the main wing spars of drones manufactured using traditional methods exhibit unstable internal quality in the corner areas. The main reasons for this include the following:

[0004] 1. When the prepreg root of the flange turns at a right angle, it makes the prepreg in the flange very prone to hollowing, which in turn affects the internal quality.

[0005] 2. When the reinforcing carbon ring is cured integrally with the flange prepreg, the cured reinforcing carbon ring becomes a rigid structure and the rear end face of the reinforcing carbon ring is flat. It cannot transmit vacuum pressure to the corner area of ​​the flange prepreg, resulting in insufficient curing pressure in the corner area of ​​the flange prepreg, which in turn affects the internal quality.

[0006] In view of this, how to provide a method to improve the internal quality of the composite material flange corner area of ​​the main wing spars of UAVs is a technical problem that urgently needs to be solved by those in the field. Summary of the Invention

[0007] The purpose of this invention is to provide a molding method for composite material flanges of the main wing spars of unmanned aerial vehicles (UAVs) to solve the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides the following solution: The present invention provides a method for forming a composite material flange for the main wing spars of an unmanned aerial vehicle (UAV), comprising the following steps:

[0009] S1: Fix the flange mold to both ends of the main wing beam tube body, and form a mold cavity with right-angle flange corners between the flange mold and the main wing beam tube body;

[0010] S2: Apply adhesive film to the flange prepreg application area on the outer surface of the main wing beam tube;

[0011] S3: Fix the end fillet to the corner of the right-angle flange. The shape of the end fillet matches the corner of the right-angle flange, and the outer side of the end fillet is an arc surface. The two ends of the arc surface are connected to the flange prepreg laying area and the inner wall of the flange mold, respectively.

[0012] S4: Apply adhesive film to the rounded surface of the end corners;

[0013] S5: The flange prepreg is laid on the flange prepreg laying area, the arc surface of the end rounded corners, and the inner wall of the flange mold to form a flange prepreg layer; a receiving cavity is formed between the outer surface of the flange prepreg layer and the mold cavity;

[0014] S6: Fix the silicone mold that matches the shape of the cavity into the cavity and vacuum seal it;

[0015] S8: The flange prepreg layer, end fillets, adhesive film and main wing beam tube body are cured into one piece;

[0016] S9: Remove the silicone mold to obtain the flange semi-finished product;

[0017] S10: Bond and fix the reinforcing carbon ring into the receiving cavity and vacuum seal it;

[0018] S11: Remove the flange mold and cut off the main flange tube body outside the end face of the flange semi-finished product to obtain the finished flange.

[0019] Furthermore, a core mold is provided inside the main wing beam tube, and the end extends outward to form an extended part. In step S1, the flange mold is fixed to the positioning hole on the extended part by a pin.

[0020] Furthermore, in step S11, the extended portion other than the end face of the flange semi-finished product is removed to obtain the flange finished product.

[0021] Furthermore, the end fillet is annular, having two right-angled surfaces and one arc surface. In step S3, the two right-angled surfaces of the end fillet are fixed at the right-angled flange corner of the mold cavity.

[0022] Furthermore, in steps S6 and S10, an isolation film and a breathable felt are wrapped around the flange prepreg layer, the flange mold, and the silicone mold, or around the flange prepreg layer, the flange mold, and the reinforcing carbon ring, and vacuum-sealed using a vacuum bag and sealant.

[0023] Preferably, the vacuum sealing pressure in step S6 is not less than 0.092 MPa.

[0024] Preferably, the vacuum sealing pressure in step S10 is 0.03 to 0.06 MPa.

[0025] Furthermore, the silicone mold is provided with silicone mold rounded corners on the arc surface corresponding to the end rounded corners.

[0026] Furthermore, the reinforcing carbon ring is provided with a reinforcing carbon ring fillet on the arc surface corresponding to the end fillet.

[0027] The present invention discloses the following technical effects:

[0028] 1. During flange forming, the end rounded corners are set at the right-angle flange corners of the flange mold to change the right-angle turn of the original flange prepreg root corner, so that the flange prepreg can turn smoothly and gently along the arc surface, and it is not easy to produce hollow phenomenon.

[0029] 2. No reinforcing carbon rings are installed during the curing of the flange prepreg. Pressure curing is achieved through a silicone mold combined with vacuum sealing. The silicone mold, with its rounded corners that correspond to the arc surface and are adapted to the shape, transmits vacuum pressure to the corner area of ​​the flange prepreg, ensuring the curing pressure in the corner area. At the same time, the silicone mold expands during the curing process, which increases the extrusion pressure on the corner area of ​​the flange prepreg, enhances the curing effect, and avoids internal quality defects. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the main wing beam tube with a core mold.

[0032] Figure 2 This is a schematic diagram of the end fillet.

[0033] Figure 3 This is a schematic diagram of the end fillet cross-section.

[0034] Figure 4 This is a schematic diagram of reinforced carbon rings.

[0035] Figure 5 This is a schematic diagram of the cross-section of the reinforced carbon ring.

[0036] Figure 6 This is a schematic diagram showing the state of fixing the flange mold to the main wing spars of the UAV.

[0037] Figure 7 This is a partial cross-sectional schematic diagram showing the flange mold fixed to the main wing spars of the UAV.

[0038] Figure 8 This is a partial cross-sectional schematic diagram showing the state where the end fillet is installed at the corner of the root of the flange mold cavity.

[0039] Figure 9 This is a schematic diagram of a silicone mold.

[0040] Figure 10 This is a cross-sectional view of a silicone mold.

[0041] Figure 11 This is a partial cross-sectional diagram showing the silicone mold installed in the cavity of the flange mold.

[0042] Figure 12 This is a schematic diagram of a semi-finished composite material flange for the main wing spars of a drone, complete with a core mold and flange mold.

[0043] Figure 13 This is a partial cross-sectional schematic diagram of a semi-finished composite material flange for the main wing spars of a drone, including a core mold and a flange mold.

[0044] Figure 14 This is a partial cross-sectional schematic diagram showing the reinforcement carbon ring bonded to the inner end face of the flange, the flange fillet, and the flange root using structural adhesive.

[0045] Figure 15 This is a schematic diagram of the finished composite material flange for the main wing spars of a drone.

[0046] Figure 16 This is a partial cross-sectional schematic diagram of the finished composite material flange for the main wing spars of a drone.

[0047] The components are as follows: 1. Core mold; 2. Main wing beam tube body; 3. End fillet; 4. Reinforcing carbon ring; 5. Flange mold; 6. Flange prepreg layer; 7. Silicone mold; 8. Flange semi-finished product; 9. Flange finished product; 201. Flange prepreg laying area; 202. Extension section; 203. Positioning round hole; 301. Arc surface; 302. Semi-circular end fillet; 303. Right angle surface; 401. Reinforcing carbon ring fillet; 402. Semi-circular reinforcing carbon ring; 501. Mold cavity; 50101. Right angle flange corner; 502. Pin; 701. Bevel; 702. Silicone mold fillet; 801. Flange inner end face; 802. Flange fillet; 803. Flange root; 901. Flange face; 902. Connecting hole; 903. Flange corner. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Example 1

[0051] This invention discloses a molding method for a composite material flange for a UAV main wing spars. The method includes a prefabricated main wing spars tube 2 with a core mold 1, an extended end portion 202, end fillets 3, a silicone mold 7, and a reinforcing carbon ring 4. The end fillets 3 are annular, having two right-angled surfaces 303 and an arc surface 301. The silicone mold 7 has silicone mold fillets 702 corresponding to the arc surface 301 of the end fillet 3, and a slope 701 is provided on the side of the silicone mold 7 away from the silicone mold fillet 702. The reinforcing carbon ring 4 has reinforcing carbon ring fillets 401 corresponding to the arc surface 301 of the end fillet 3. The end fillets 3 are formed by joining two semi-circular end fillets 302. The end fillets 3 can be formed by processing a cured composite material sheet or by directly curing it using a mold. The reinforcing carbon ring 4 is formed by joining two semi-circular reinforcing carbon rings 402. The reinforcing carbon ring 4 can be formed by processing a cured composite material sheet or by directly curing it using a mold.

[0052] Specifically, the following steps are included:

[0053] S1: Fix the flange mold 5 at both ends of the main wing beam tube body 2. The flange mold 5 is fixed at the positioning round hole 203 on the extension part 202 by the pin 502. A mold cavity 501 with a right-angle flange corner 50101 is formed between the flange mold 5 and the main wing beam tube body 2.

[0054] S2: Roughen and clean the flange prepreg area 201 on the outer surface of the main wing beam tube body 2, and then apply the adhesive film; the flange prepreg area 201 refers to the area within a certain length range formed by extending along the length direction of the outer surface of the main wing beam tube body 2 with the right angle flange corner 50101 as the starting line.

[0055] S3: Fix the end fillet 3 at the right angle flange corner 50101. The two right angle surfaces 303 of the end fillet 3 are fixed at the right angle flange corner 50101 of the mold cavity 501. The outer side of the end fillet 3 is an arc surface 301. The two ends of the arc surface 301 are connected to the flange prepreg laying area 201 and the inner side wall of the flange mold 5, respectively.

[0056] S4: Apply adhesive film to the arc surface 301 of the end fillet 3;

[0057] S5: The flange prepreg is laid on the flange prepreg laying area 201, the arc surface 301 of the end fillet 3, and the inner wall of the flange mold 5 to form a flange prepreg layer 6; a receiving cavity is formed between the outer surface of the flange prepreg layer 6 and the mold cavity 501.

[0058] S6: Fix the silicone mold 7, which is adapted to the shape of the cavity, into the cavity. Wrap the flange prepreg layer 6, flange mold 5 and silicone mold 7 with a release film and breathable felt. Vacuum seal the cavity using a vacuum bag and sealant (the various auxiliary structures used in vacuum sealing are hereinafter referred to as vacuum auxiliary materials). The vacuum sealing pressure is 0.095MPa.

[0059] S8: The flange prepreg layer 6, end fillet 3, adhesive film and main wing beam tube 2 are cured into one piece by a curing oven;

[0060] S9: Remove the vacuum auxiliary material and take off the silicone mold 7 to obtain the flange semi-finished product 8;

[0061] S10: Roughen the inner end face 801, the rounded corner 802, and the root 803 of the flange semi-finished product 8. Bond and fix the reinforcing carbon ring 4 into the receiving cavity with structural adhesive. Wrap the flange prepreg layer 6, the flange mold 5, and the reinforcing carbon ring 4 with an isolation film and a breathable felt. Vacuum seal the product with a vacuum bag and sealant. The vacuum sealing pressure is 0.03 MPa.

[0062] S11: Remove the flange mold 5, cut off the extended part 202 outside the end face of the flange semi-finished product 8 to form the flange face 901, and after cutting, machine the connecting hole 902 on the flange semi-finished product 8 to obtain the flange finished product 9, which has an arc-shaped flange corner 903.

[0063] The composite material flange for the main wing spars of the UAV prepared in Example 1 was subjected to a standard strength test for the UAV. The results showed that the flange had no fractures or cracks.

[0064] Example 2

[0065] The difference between this embodiment and Embodiment 1 is that the vacuum sealing pressure in step S10 is 0.06 MPa.

[0066] The composite material flange for the main wing spars of the UAV prepared in Example 2 was subjected to a standard strength test, and the results showed that the flange showed no fractures or cracks. An ultimate load test was also conducted on the flange prepared in Example 2, and the results showed that its ultimate load could reach 16686 Nm, while the ultimate load of the flange prepared using the conventional method was 14454 Nm.

[0067] Example 3

[0068] The difference between this embodiment and Embodiment 1 is that the vacuum sealing pressure in step S6 is 0.092 MPa.

[0069] The composite material flange for the main wing spars of the UAV prepared in Example 3 was subjected to a standard strength test. The results showed that the flange developed cracks and had a tendency to break.

[0070] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0071] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for forming a composite material flange for the main wing spars of an unmanned aerial vehicle (UAV), characterized in that, Includes the following steps: S1: Fix the flange mold (5) at both ends of the main wing beam tube body (2), and form a mold cavity (501) with a right-angle flange corner (50101) between the flange mold (5) and the main wing beam tube body (2). S2: Apply adhesive film to the flange prepreg application area (201) on the outer surface of the main wing beam tube (2); S3: Fix the end fillet (3) at the right angle flange corner (50101). The shape of the end fillet (3) matches the right angle flange corner (50101), and the outer side of the end fillet (3) is an arc surface (301). The two ends of the arc surface (301) are connected to the flange prepreg laying area (201) and the inner wall of the flange mold (5), respectively. S4: Apply adhesive film to the arc surface (301) of the end fillet (3); S5: The flange prepreg is laid on the flange prepreg laying area (201), the arc surface (301) of the end fillet (3) and the inner wall of the flange mold (5) to form a flange prepreg layer (6); a receiving cavity is formed between the outer surface of the flange prepreg layer (6) and the mold cavity (501); S6: Fix the silicone mold (7) that matches the shape of the cavity into the cavity and vacuum seal it; S7: The flange prepreg layer (6), end fillet (3), adhesive film and main wing beam tube body (2) are cured into one piece; S8: Remove the silicone mold (7) to obtain the flange semi-finished product (8); S9: Bond and fix the reinforcing carbon ring (4) into the cavity and vacuum seal it; S10: Remove the flange mold (5) and cut off the main wing beam pipe body (2) outside the end face of the flange semi-finished product (8) to obtain the flange finished product (9); The end fillet (3) is annular, with two right angle surfaces (303) and one arc surface (301). In step S3, the two right angle surfaces (303) of the end fillet (3) are fixed at the right angle flange corner (50101) of the mold cavity (501). The silicone mold (7) is provided with a silicone mold fillet (702) on the arc surface (301) corresponding to the end fillet (3). The reinforced carbon ring (4) is provided with a reinforced carbon ring fillet (401) on the arc surface (301) corresponding to the end fillet (3).

2. The forming method of a composite material flange for a UAV main wing spars according to claim 1, characterized in that, The main wing beam tube (2) is provided with a core mold (1) inside. The end of the main wing beam tube (2) extends outward to form an extension (202). In step S1, the flange mold (5) is fixed to the positioning hole (203) on the extension (202) by a pin (502).

3. The forming method of a composite material flange for a UAV main wing spars according to claim 2, characterized in that, In step S10, the extended portion (202) outside the end face of the flange semi-finished product (8) is cut off to obtain the flange finished product (9).

4. The forming method of a composite material flange for a UAV main wing spars according to claim 1, characterized in that, In step S6, an isolation film and a breathable felt are wrapped around the flange prepreg layer (6), the flange mold (5) and the silicone mold (7), and vacuum sealing is performed using a vacuum bag and sealant. Alternatively, in step S9, an isolation film and a breathable felt are wrapped around the flange prepreg layer (6), the flange mold (5) and the reinforcing carbon ring (4), and vacuum sealing is performed using a vacuum bag and sealant.

5. The forming method of a composite material flange for a UAV main wing spars according to claim 4, characterized in that, In step S6, the pressure of vacuum sealing is not less than 0.092 MPa.

6. The forming method of a composite material flange for a UAV main wing spars according to claim 4, characterized in that, In step S9, the vacuum sealing pressure is 0.03~0.06MPa.

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