A method for integrally molding a drone composite fuselage by co-bonding and co-curing

Abstract

This invention belongs to the field of composite material molding and manufacturing technology for unmanned aerial vehicles (UAVs). It discloses a method for co-bonding and co-curing integral molding of composite material fuselage for UAVs. The method involves pre-laying and compacting a first U-shaped partition, a second U-shaped partition, and a cap-shaped beam. The first U-shaped partition is positioned by being snapped together by a first and a second reinforcing stringer. The second U-shaped partition is positioned by being snapped together by a third and a fourth reinforcing stringer. The first and second U-shaped partitions are respectively bonded to the upper and lower cap plates at both ends of the cap-shaped beam. The first and second metal partitions are bonded to the ends of the first and second U-shaped partitions. Then, the upper and lower wall panels are molded together, and all parts are directly co-cured and molded, reducing the workload of secondary assembly and connection. Due to the breakage of the perforated fibers, the strength loss caused by secondary connection is reduced, and the weight of the fuselage is reduced.

Description

Technical Field

[0001] This invention belongs to the field of composite material molding and manufacturing technology for unmanned aerial vehicles (UAVs), specifically relating to a method for co-bonding and co-curing integral molding of composite material fuselage for UAVs. Background Technology

[0002] The composite material fuselage of a drone typically includes wall panels, reinforcing beams, and reinforcing frames. Currently, the prototype is manufactured using a method where only the upper and lower wall panels are composite material parts, while the reinforcing beams (trusses), frames, and other parts are all metal parts. These parts are molded and manufactured separately, and then assembled using methods such as secondary adhesive riveting and screwing.

[0003] The existing prototype has the following problems:

[0004] (1) After the wall panels, beams, frames and other parts are formed separately, they are assembled with secondary glue and rivets, which increases the workload of secondary assembly and connection, and increases the number of locators in each partition frame of the assembly frame.

[0005] (2) The increased use of standard parts such as rivets, screws, and bolts has increased the structural weight;

[0006] (3) The secondary bonding has gaps between the metal parts and the wall panel, which increases the uncertainty of the adhesive layer thickness;

[0007] (4) During the secondary assembly and fixing, the structural strength was lost due to the breakage of the hole-making fiber.

[0008] To address these issues, we propose a method for co-bonding and co-curing integral molding of composite material fuselages for UAVs. This method allows for direct co-curing of all components, reducing the workload of secondary assembly and connection, minimizing strength loss due to secondary connections, and reducing fuselage weight. Summary of the Invention

[0009] The purpose of this invention is to provide a method for co-bonding and co-curing integral molding of composite material fuselages for unmanned aerial vehicles (UAVs), in order to solve the problems mentioned in the background art regarding the prior art.

[0010] (1) After the wall panels, beams, frames and other parts are formed separately, they are assembled with secondary glue and rivets, which increases the workload of secondary assembly and connection, and increases the number of locators in each partition frame of the assembly frame.

[0011] (2) The increased use of standard parts such as rivets, screws, and bolts has increased the structural weight;

[0012] (3) The secondary bonding has gaps between the metal parts and the wall panel, which increases the uncertainty of the adhesive layer thickness;

[0013] (4) During the secondary assembly and fixing, the structural strength was lost due to the breakage of the hole-making fiber.

[0014] To achieve the above objectives, the present invention adopts the following technical solution:

[0015] A method for co-bonding and co-curing a composite material fuselage for unmanned aerial vehicles (UAVs) includes the following steps:

[0016] S1. The first U-shaped partition, the second U-shaped partition, and the hat-shaped beam are pre-laid and compacted. The pre-laying and compaction refers to laying each component in the design position and pre-compacting it to remove air bubbles.

[0017] The cap-shaped beam has an upper cap plate and a lower cap plate integrally formed at both ends. The two ends of one side of the upper cap plate are respectively bonded to one end of the inner side of the first U-shaped partition and one end of the inner side of the second U-shaped partition. The two ends of one side of the lower cap plate are respectively bonded to the other end of the inner side of the first U-shaped partition and the other end of the inner side of the second U-shaped partition.

[0018] S2. The first metal partition frame and the second metal partition frame are respectively embedded between multiple sets of first U-shaped partition frames and multiple sets of second U-shaped partition frames;

[0019] S3. Position the first U-shaped partition and the second U-shaped partition using the first reinforcing stringer, the second reinforcing stringer, the third reinforcing stringer and the fourth reinforcing stringer;

[0020] The outer side of the first reinforcing truss is provided with a first slot for multiple sets of first U-shaped partitions to be inserted, and the multiple sets of first slots are arranged at equal intervals. The outer side of the second reinforcing truss is provided with a second slot for multiple sets of first U-shaped partitions to be engaged, and the multiple sets of second slots are arranged at equal intervals.

[0021] The outer side of the third reinforcing truss is provided with a third slot for multiple sets of second U-shaped partitions to be engaged, and the outer side of the fourth reinforcing truss is provided with a fourth slot for multiple sets of second U-shaped partitions to be engaged. The multiple sets of third slots and multiple sets of fourth slots are all arranged at equal intervals.

[0022] S5. After the mold is closed, the overall structure is vacuum bagged and heated for co-curing to achieve the overall molding of the machine body.

[0023] S4. The upper and lower wall panels are closed by connecting guide pins. The two outer ends of the first U-shaped partition frame are respectively bonded to the inner walls of the upper and lower wall panels. The two outer ends of the second U-shaped partition frame are respectively bonded to the inner walls of the upper and lower wall panels.

[0024] Preferably, the upper wall panel has multiple sets of connecting guide pins fixedly connected to one side of the opening, and the lower wall panel has connecting guide holes for the multiple sets of connecting guide pins to slide into one side of the opening.

[0025] Preferably, one end of the upper wall panel is integrally formed with an upper machine head, and one end of the lower wall panel is integrally formed with a lower machine head, wherein the opening side of the upper machine head matches the opening side of the lower machine head.

[0026] Preferably, the other end of the upper wall panel is integrally formed with an upper engine housing, and the other end of the lower wall panel is integrally formed with a lower engine housing, wherein the opening side of the upper engine housing and the opening side of the lower engine housing are matched.

[0027] Preferably, the first reinforcing stringer and the second reinforcing stringer have the same length, the third reinforcing stringer and the fourth reinforcing stringer have the same length, and the length of the first reinforcing stringer is greater than the length of the third reinforcing stringer.

[0028] Preferably, the first reinforcing stringer, the second reinforcing stringer, the third reinforcing stringer and the fourth reinforcing stringer are arranged in a rectangular array, the first metal partition is disposed between the first reinforcing stringer and the third metal partition, and the second metal partition is disposed between the second reinforcing stringer and the fourth reinforcing stringer.

[0029] Preferably, the overall cross-section of the hat-shaped beam, the upper hat plate, and the lower hat plate is arranged in an I-shape, one side of the first metal partition is bonded to the inner wall of the upper wall plate, and one side of the second metal partition is bonded to the inner wall of the lower wall plate.

[0030] Preferably, the cross-section of the inner wall after the upper and lower wall panels are molded together is the same as the cross-section of the first U-shaped partition frame, and the opening side of the upper wall panel is bonded to the opening side of the lower wall panel.

[0031] The present invention proposes a method for co-bonding and co-curing integral molding of composite material fuselage for unmanned aerial vehicles (UAVs), which has the following advantages compared with the prior art:

[0032] The present invention relates to the cooperation between the upper wall panel, lower wall panel, first U-shaped partition frame, second U-shaped partition frame, cap-shaped beam, first reinforcing stringer, second reinforcing stringer, third reinforcing stringer, and fourth reinforcing stringer. The first U-shaped partition frame is positioned by being snapped together with the first and second reinforcing stringers, and the second U-shaped partition frame is positioned by being snapped together with the third and fourth reinforcing stringers. The first and second U-shaped partition frames are respectively bonded to the upper and lower cap plates at both ends of the cap-shaped beam, and the first and second metal partition frames are bonded to the ends of the first and second U-shaped partition frames. Then, the upper and lower wall panels are molded together, and all parts are directly cured and formed together, reducing the workload of secondary assembly and connection. Due to the breakage of the holes in the fiber, the strength loss caused by secondary connection is reduced, and the weight of the machine body is reduced. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the co-bonded and co-cured body of the present invention;

[0034] Figure 2 This is a schematic diagram of the mold-closing structure of the present invention from a low angle.

[0035] Figure 3 This is a top view of the structure of the present invention before mold closing;

[0036] Figure 4 This is a schematic diagram of the internal structure of the upper and lower wall panels of the present invention.

[0037] In the diagram: 1. Upper wall panel; 2. Lower wall panel; 3. Upper engine housing; 4. Lower engine housing; 5. Upper engine head; 6. Lower engine head; 7. Connecting guide pin; 8. Connecting guide hole; 9. First reinforcing stringer; 10. Second reinforcing stringer; 11. First metal partition frame; 12. Second metal partition frame; 13. Third reinforcing stringer; 14. Fourth reinforcing stringer; 15. Hat-shaped beam; 16. Upper cap plate; 17. Lower cap plate; 18. First slot; 19. Second slot; 20. Third slot; 21. Fourth slot; 22. First U-shaped partition frame; 23. Second U-shaped partition frame. Detailed Implementation

[0038] 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. The specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention. 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.

[0039] This invention provides, for example Figure 1-4 The method for co-bonding and co-curing a composite material fuselage of a drone, as shown, includes the following steps:

[0040] S1. The first U-shaped partition 22, the second U-shaped partition 23 and the hat-shaped beam 15 are pre-laid and compacted. Pre-laying and compacting means laying each component in the design position and pre-compacting it to remove air bubbles.

[0041] The two ends of the hat-shaped beam 15 are integrally formed with an upper hat plate 16 and a lower hat plate 17. One end of the upper hat plate 16 is bonded to one end of the inner side of the first U-shaped partition 22 and one end of the inner side of the second U-shaped partition 23, respectively. The two ends of the lower hat plate 17 are bonded to the other end of the inner side of the first U-shaped partition 22 and the other end of the inner side of the second U-shaped partition 23, respectively. The upper hat plate 16 and the lower hat plate 17 at both ends of the hat-shaped beam 15 are bonded to the first U-shaped partition 22 and the second U-shaped partition 23 firstly to facilitate mold closing.

[0042] S2. The first metal partition 11 and the second metal partition 12 are respectively embedded between multiple sets of first U-shaped partitions 22 and multiple sets of second U-shaped partitions 23. The stability between the first U-shaped partitions 22, the second U-shaped partitions 23, the upper cap plate 16, the lower cap plate 17 and the cap-shaped beam 15 is improved by the first metal partition 11 and the second metal partition 12.

[0043] S3. The first U-shaped partition 22 and the second U-shaped partition 23 are positioned by the first reinforcing stringer 9, the second reinforcing stringer 10, the third reinforcing stringer 13 and the fourth reinforcing stringer 14. The first reinforcing stringer 9, the second reinforcing stringer 10, the third reinforcing stringer 13 and the fourth reinforcing stringer 14 connect multiple sets of first U-shaped partitions 22 and multiple sets of second U-shaped partitions 23 into a whole, so as to facilitate fitting with the upper wall panel 1 and the lower wall panel 2.

[0044] The outer side of the first reinforcing truss 9 is provided with a first slot 18 for multiple sets of first U-shaped partitions 22 to be embedded. The multiple sets of first slots 18 are arranged at equal intervals. The outer side of the second reinforcing truss 10 is provided with a second slot 19 for multiple sets of first U-shaped partitions 22 to be engaged. The multiple sets of second slots 19 are arranged at equal intervals, which improves the stability of the first U-shaped partitions 22, thereby improving the stability of the fit between the upper wall panel 1 and the lower wall panel 2.

[0045] The outer side of the third reinforcing truss 13 is provided with a third slot 20 for multiple sets of second U-shaped partitions 23 to be engaged, and the outer side of the fourth reinforcing truss 14 is provided with a fourth slot 21 for multiple sets of second U-shaped partitions to be engaged. The multiple sets of third slots 20 and multiple sets of fourth slots 21 are all arranged at equal intervals to improve the stability of multiple sets of second U-shaped partitions 23, thereby improving the stability of the upper wall panel 1 and the lower wall panel 2 when they are closed.

[0046] S4. The upper wall panel 1 and the lower wall panel 2 are closed by connecting guide pin 7. The two outer ends of the first U-shaped partition 22 are respectively bonded to the inner wall of the upper wall panel 1 and the inner wall of the lower wall panel 2. The two outer ends of the second U-shaped partition 23 are respectively bonded to the inner wall of the upper wall panel 1 and the inner wall of the lower wall panel 2, and are bonded together as one unit.

[0047] S5. After the mold is closed, the overall structure is vacuum bagged and heated for co-curing to achieve the overall molding of the machine body.

[0048] Vacuum bags are prepared by vacuuming the entire machine body. Areas where vacuum bags cannot be operated are filled with high-density foam or silicone rubber. Large areas are filled with high-density foam or silicone rubber to the areas where vacuum bags can be prepared, and the vacuum bag pressure is transferred to each part. Small areas are pressured by applying curing silicone rubber or expandable film rolls.

[0049] To prevent vacuum bags from breaking, they need to be filled with high-density foam, which is difficult to remove and easily damaged. Uncured silicone rubber is used to fill the vacuum bags and their installation positions are marked to ensure their continued use.

[0050] For the vacuum bag area of ​​easy bridging vacuum preparation caused by the combination of the frame positioning component and the wall panel, a matching fabric soft film is specially manufactured to apply pressure; surface treatment of metal parts, application of primer, and additional application of adhesive film at the contact position between metal parts and wall panel before prepreg assembly.

[0051] After demolding, due to the removal of the vacuum bag pressure and the difference in thermal expansion coefficients between the composite material body and the cured mold, to avoid internal stress, at 60-65℃, first remove the spacer locators, then remove the upper mold. Finally, gently insert thin composite material sheets around the body, and then insert plastic wedges along the gaps, applying even force around the edges until the body detaches from the cured mold. Clean the internal cavity of the body of process foam, surface nodules, and excess material.

[0052] Multiple sets of connecting guide pins 7 are fixedly connected to one side of the opening of the upper wall panel 1. A connecting guide hole 8 is provided on one side of the opening of the lower wall panel 2 for the multiple sets of connecting guide pins 7 to slide and insert. The connecting guide pins 7 and connecting guide holes 8 facilitate the mold closing of the upper wall panel 1 and the lower wall panel 2. The layup position, angle and sequence are based on the digital model specifications. For parts of U-shaped partitions and U-shaped corner boxes, the unidirectional fabric laying angle deviation is ±3° and the fabric laying angle deviation is ±5°. For parts of wall panels and beams, the unidirectional fabric laying deviation angle is ±1° and the fabric laying direction tolerance is ±5°. For unidirectional fabrics laid along the load-bearing direction and fiber direction, the allowable overlap size is 10-20mm. For unidirectional fabrics laid along the load-bearing direction, the allowable butt joint width in the width direction is 0~1mm.

[0053] The upper wall panel 1 has an integrally formed upper head 5 at one end, and the lower wall panel 2 has an integrally formed lower head 6 at one end. The opening side of the upper head 5 matches the opening side of the lower head 6, improving the fit.

[0054] The other end of the upper wall panel 1 is integrally formed with an upper engine housing 3, and the other end of the lower wall panel 2 is integrally formed with a lower engine housing 4. The opening side of the upper engine housing 3 and the opening side of the lower engine housing 4 are matched to improve the fit and thus improve the stability of the fuselage.

[0055] The first reinforcing stringer 9 and the second reinforcing stringer 10 have the same length, and the third reinforcing stringer 13 and the fourth reinforcing stringer 14 have the same length. The length of the first reinforcing stringer 9 is greater than the length of the third reinforcing stringer 13. The first reinforcing stringer 9 and the second reinforcing stringer 10 connect the two ends of the inner sidewall of the upper wall panel 1 to improve the overall strength.

[0056] The first reinforcing stringer 9, the second reinforcing stringer 10, the third reinforcing stringer 13, and the fourth reinforcing stringer 14 are arranged in a rectangular array. The first metal partition 11 is located between the first reinforcing stringer 9 and the third metal partition, and the second metal partition 12 is located between the second reinforcing stringer 10 and the fourth reinforcing stringer 14, thereby improving the deformation resistance of the fuselage after mold closing.

[0057] The overall cross-section of the hat-shaped beam 15, the upper hat plate 16, and the lower hat plate 17 is set in an I-shape. One side of the first metal partition 11 is bonded to the inner wall of the upper wall plate 1, and one side of the second metal partition 12 is bonded to the inner wall of the lower wall plate 2 to prevent the upper wall plate 1 and the lower wall plate 2 from being deformed by pressure.

[0058] The inner wall cross-section of the upper wall panel 1 and the lower wall panel 2 after mold closing is the same as the cross-section of the first U-shaped partition frame 22. The opening side of the upper wall panel 1 is bonded to the opening side of the lower wall panel 2, and the overall fit is high.

[0059] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for integral molding of a UAV composite material fuselage through co-bonding and co-curing, characterized in that, Includes the following steps: S1. The first U-shaped partition (22), the second U-shaped partition (23) and the hat-shaped beam (15) are pre-laid and compacted. The pre-laying and compaction refers to laying each component in the design position and pre-compacting it to remove air bubbles. The cap-shaped beam (15) has an upper cap plate (16) and a lower cap plate (17) integrally formed at both ends. The two ends of one side of the upper cap plate (16) are respectively bonded to one end of the inner side of the first U-shaped partition (22) and one end of the inner side of the second U-shaped partition (23). The two ends of one side of the lower cap plate (17) are respectively bonded to the other end of the inner side of the first U-shaped partition (22) and the other end of the inner side of the second U-shaped partition (23). S2. The first metal partition (11) and the second metal partition (12) are respectively embedded between multiple sets of first U-shaped partitions (22) and multiple sets of second U-shaped partitions (23); S3. The first U-shaped partition (22) and the second U-shaped partition (23) are positioned by the first reinforcing stringer (9), the second reinforcing stringer (10), the third reinforcing stringer (13) and the fourth reinforcing stringer (14); The outer side of the first reinforcing truss (9) is provided with a first slot (18) for multiple sets of first U-shaped partitions (22) to be embedded, and the multiple sets of first slots (18) are arranged at equal intervals. The outer side of the second reinforcing truss (10) is provided with a second slot (19) for multiple sets of first U-shaped partitions (22) to be engaged, and the multiple sets of second slots (19) are arranged at equal intervals. The outer side of the third reinforcing truss (13) is provided with a third slot (20) for multiple sets of second U-shaped partitions (23) to be engaged, and the outer side of the fourth reinforcing truss (14) is provided with a fourth slot (21) for multiple sets of second U-shaped partitions to be engaged. The multiple sets of third slots (20) and multiple sets of fourth slots (21) are all arranged at equal intervals. S4. The upper wall panel (1) and the lower wall panel (2) are closed by connecting guide pin (7). The two outer ends of the first U-shaped partition (22) are respectively bonded to the inner wall of the upper wall panel (1) and the inner wall of the lower wall panel (2). The two outer ends of the second U-shaped partition (23) are respectively bonded to the inner wall of the upper wall panel (1) and the inner wall of the lower wall panel (2). S5. After the mold is closed, the overall structure is vacuum bagged and heated for co-curing to achieve the overall molding of the machine body.

2. The method for co-bonding and co-curing integral molding of a UAV composite material fuselage according to claim 1, characterized in that: The upper wall plate (1) has multiple sets of connecting guide pins (7) fixedly connected to one side of the opening, and the lower wall plate (2) has a connecting guide hole (8) for the multiple sets of connecting guide pins (7) to slide into one side of the opening.

3. The method for co-bonding and co-curing integral molding of a UAV composite material fuselage according to claim 2, characterized in that: The upper wall panel (1) has an upper machine head (5) integrally formed at one end, and the lower wall panel (2) has a lower machine head (6) integrally formed at one end. The opening side of the upper machine head (5) matches the opening side of the lower machine head (6).

4. The method for co-bonding and co-curing integral molding of a UAV composite material fuselage according to claim 3, characterized in that: The upper wall panel (1) has an upper engine housing (3) integrally formed at the other end, and the lower wall panel (2) has a lower engine housing (4) integrally formed at the other end. The opening side of the upper engine housing (3) matches the opening side of the lower engine housing (4).

5. The method for co-bonding and co-curing integral molding of a UAV composite material fuselage according to claim 4, characterized in that: The first reinforcing stringer (9) and the second reinforcing stringer (10) have the same length, and the third reinforcing stringer (13) and the fourth reinforcing stringer (14) have the same length. The length of the first reinforcing stringer (9) is greater than the length of the third reinforcing stringer (13).

6. The method for co-bonding and co-curing integral molding of a UAV composite material fuselage according to claim 5, characterized in that: The first reinforcing stringer (9), the second reinforcing stringer (10), the third reinforcing stringer (13) and the fourth reinforcing stringer (14) are arranged in a rectangular array. The first metal partition (11) is disposed between the first reinforcing stringer (9) and the third metal partition, and the second metal partition (12) is disposed between the second reinforcing stringer (10) and the fourth reinforcing stringer (14).

7. The method for co-bonding and co-curing integral molding of a UAV composite material fuselage according to claim 6, characterized in that: The overall cross-section of the hat-shaped beam (15), the upper hat plate (16) and the lower hat plate (17) is set in an I-shape. One side of the first metal partition (11) is bonded to the inner wall of the upper wall plate (1), and one side of the second metal partition (12) is bonded to the inner wall of the lower wall plate (2).

8. The method for co-bonding and co-curing integral molding of a UAV composite material fuselage according to claim 7, characterized in that: The inner wall cross-section of the upper wall panel (1) and the lower wall panel (2) after being molded together is the same as the cross-section of the first U-shaped partition frame (22), and the opening side of the upper wall panel (1) is bonded to the opening side of the lower wall panel (2).

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