Rivets and devices for riveting composite materials to metal plates

Abstract

This utility model discloses a rivet and device for riveting composite materials to metal plates in the field of material joining technology. It includes an upper mold and a lower mold, and further includes: an embedding groove disposed at the end of the lower mold for accommodating and engaging the plate; and a pressure ring fixedly installed on the upper mold for pressing the plate. A rivet head slides along the axis within the central clearance hole of the pressure ring, and a drive head coaxially nested within the pressure ring, driven by an external drive unit. This utility model uses rivets with microstructured protrusions and concave blocks on the end face of the rivet legs, which, in conjunction with the drive head, drive the rivet to rotate at high speed to cut the composite material. Simultaneously, the pressure ring presses the composite plate, eliminating the need for pre-drilled holes in the composite material to complete the punching and cutting process. This simplifies the riveting process, reduces the difficulty of aligning tooling and holes, and avoids the problems of fiber breakage, matrix cracking, interface delamination, and delamination in composite materials caused by direct punching or rotary friction-generated heat cutting in existing technologies.

Description

Technical Field

[0001] This utility model relates to the field of material joining technology, and in particular to a rivet and device for riveting composite materials to metal plates. Background Technology

[0002] Thermoplastic carbon fiber composites, as a new type of composite material, have advantages such as high specific strength and specific modulus, good fatigue resistance, low coefficient of thermal expansion and good corrosion resistance, and are widely used in aerospace, shipbuilding and automotive fields.

[0003] In practical engineering applications, thermoplastic composites are often connected to traditional metal materials such as steel and aluminum alloys by riveting. However, due to the poor plasticity of carbon fiber composites, existing riveting technologies have many problems: on the one hand, pre-drilling holes in the composite material is required before riveting, which not only increases the riveting process but also increases the difficulty of aligning the tooling with the holes; on the other hand, fiber breakage, matrix cracking, interface delamination, and delamination are prone to occur during the riveting process, reducing joint performance and even directly causing joint failure. Moreover, in the cross tensile test, the composite material side is also prone to tearing failure. At the same time, the poor fluidity of the composite material means that if the riveting material is stored in most of the space inside the rivet, the effective interlocking between the rivet leg and the metal plate will be limited, further restricting the riveting performance. Therefore, we urgently need rivets and devices for riveting composite materials to metal plates to solve the above problems. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a rivet and device for riveting composite materials and metal plates. By using a rivet with micro-structured bumps on the end face, a drive head for rotary cutting, a large-diameter thin flange design, a pressure ring for clamping, and a rivet through groove to collect the cut material and a lower mold forming area to guide deformation, it achieves the elimination of pre-drilled holes, reduces composite material defects, avoids stretching and tearing, improves riveting interlocking performance and appearance, simplifies the process, and ensures joint reliability.

[0005] The purpose of this utility model is achieved as follows: it includes an upper mold and a lower mold, and further includes: an embedding groove provided at the end of the lower mold for accommodating and engaging the plate; a pressing ring fixedly installed on the upper mold for pressing the plate, wherein a rivet head is slidably disposed in the central clearance hole of the pressing ring, and a drive head coaxially nested in the pressing ring and driven by an external drive unit, and a rivet is engaged at the end of the drive head.

[0006] Optionally, the rivet consists of a flange end and a straight rod end. The flange end has a connecting groove for connecting with the end of the drive head, and the straight rod end has a riveting groove for riveting. The connecting groove and the riveting groove are connected.

[0007] Optionally, the cross-sectional shape of the riveting groove is funnel-shaped.

[0008] Optionally, the end face of the rivet away from the flange end is provided with a circumferential protrusion for cutting.

[0009] Optionally, the flange end is a large-diameter thin flange structure.

[0010] Optionally, a forming area is provided in the embedding groove corresponding to the position of the rivet. The shape of the forming area is adapted to the deformation shape of the rivet end after piercing the metal plate, and is used to cooperate with the rivet to form a locking area.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: 1. This utility model uses rivets with microstructured protrusions and concave blocks on the end face of the rivet legs, and a drive head to drive the rivet to rotate at high speed to cut composite materials. At the same time, the pressure ring is used to press the combined plate. The punching and cutting of the composite material can be completed without pre-drilling holes in the composite material. This simplifies the riveting process, reduces the difficulty of aligning the tooling and the hole, and avoids the problems of fiber breakage, matrix cracking, interface delamination and delamination of composite materials caused by direct punching or rotary friction heat-generating cutting in the prior art. It achieves cutting of composite materials without obvious defects.

[0012] 2. This utility model, by employing rivets with a large-diameter, thin-flange structure, disperses the stress on the composite material side during cross tensile testing, solving the problem in the prior art where the composite material's strength is too weak, leading to easy pull-through failure of the composite material side during cross tensile testing. Simultaneously, the rivet's connecting groove and riveting groove are connected to form a through channel, allowing the composite material material cut during riveting to be pushed upwards into the connecting groove and secured, preventing material from falling off and not occupying the interlocking space between the lower end of the rivet and the metal plate. This solves the problem in the prior art where composite material material cuts occupy rivet space, resulting in limited effective interlocking between the rivet leg and the metal plate, thus improving the interlocking performance and aesthetic appearance of the riveted joint. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the orthographic structure of the upper and lower molds provided by this utility model.

[0015] Figure 2 This is a schematic diagram of the half-section structure of the upper and lower molds provided by this utility model.

[0016] Figure 3This is a schematic diagram of the lower mold structure provided by this utility model.

[0017] Figure 4 This is a schematic diagram of the rivet structure provided by this utility model.

[0018] Figure 5 This is a perspective view of the rivet structure provided by this utility model.

[0019] Figure 6 This is a partially enlarged structural schematic diagram provided by this utility model.

[0020] Figure 7 This is a riveting diagram provided by this utility model.

[0021] Figure 8 This is a schematic diagram of the punching-riveting process provided by this utility model.

[0022] In the diagram: 1. Upper mold; 2. Lower mold; 3. Embedded groove; 4. Pressure ring; 5. Riveting head; 6. Drive head; 7. Rivet; 71. Flange end; 72. Straight rod end; 73. Connecting groove; 74. Riveting groove; 75. Breast and groove. Detailed Implementation

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0024] like Figure 1-8 As shown in the figure, the present invention provides a rivet 7 and device for riveting composite materials and metal plates, including an upper mold 1 and a lower mold 2.

[0025] It also includes an embedding groove 3 at the end of the lower mold 2 for accommodating and engaging the plate. The embedding groove 3 has a forming area corresponding to the position of the rivet 7. The shape of the forming area is adapted to the deformation shape of the end of the rivet 7 after piercing the metal plate, and is used to cooperate with the rivet 7 to form a locking area.

[0026] Here, an embedding groove 3 is provided at the end of the lower mold 2. The embedding groove 3 is used to accommodate the composite plate and the metal plate to achieve the positioning of the composite plate. A forming area is provided in the embedding groove 3 corresponding to the position of the rivet 7. The shape of the forming area is adapted to the deformation shape of the end of the rivet 7 after piercing the metal plate, and is used to cooperate with the rivet 7 to form a locking area.

[0027] Furthermore, the embedded groove 3 enables precise positioning of the composite plate, avoiding riveting position deviation caused by plate displacement during riveting, providing an accurate benchmark for subsequent rotary cutting and stamping riveting, and reducing the risk of riveting defects caused by inaccurate positioning; its internal forming area can cooperate with the deformation of the end of the rivet 7 to form a locking area, ensuring the mechanical interlocking strength between the rivet 7 and the metal plate, and avoiding interlocking failure caused by irregular deformation.

[0028] A pressure ring 4 is fixedly installed on the upper mold 1 to press the sheet metal.

[0029] Here, the pressure ring 4 is fixedly installed on the upper mold 1 to press down and tighten the combined plate before riveting, and fix the combined plate in the embedded groove 3.

[0030] Furthermore, the pressure ring 4 prevents the composite plate from shaking or shifting during rotary cutting and stamping riveting, reducing problems such as irregular cutting and delamination of composite materials caused by loose sheet material. At the same time, it can counteract the upward reaction force generated by the rivet 7 during rotary cutting, ensuring that the composite material plate remains stable during the cutting process, providing stable working conditions for stable cutting of composite materials and subsequent riveting.

[0031] The rivet head 5 slides along the axis inside the center clearance hole of the pressure ring 4.

[0032] Here, the rivet head 5 is located in the central clearance hole of the pressure ring 4 and can slide along the axis of the central clearance hole. The sliding direction is perpendicular to the surface of the composite plate. After the rivet 7 cuts through the composite material plate, the rivet head 5 slides downward and applies pressure to the rivet 7.

[0033] Furthermore, the rivet head 5 can apply uniform and vertical pressure to the rivet 7, ensuring that the rivet 7 stably pierces the metal plate under pressure, avoiding uneven deformation of the rivet leg due to pressure deviation, and ensuring that the end of the rivet 7 forms an effective and uniform mechanical interlock with the metal plate, providing pressure guarantee for the reliable interlock between the rivet 7 and the metal plate.

[0034] The pressure ring 4 has a drive head 6 coaxially nested inside it, which is driven by an external drive unit.

[0035] Here, the drive head 6 is coaxially nested inside the pressure ring 4, with one end connected to the external drive unit and the other end engaged with the connecting groove 73 of the rivet 7. The external drive unit can drive the rivet 7 to rotate at high speed through the drive head 6. After the rivet 7 cuts through the composite material plate, the drive head 6 stops rotating and reduces the pressure.

[0036] Furthermore, the drive head 6 can achieve stable transmission of rotational power, enabling the rivet 7 to obtain a sufficient and uniform rotational speed, avoiding incomplete or excessive cutting of composite materials due to speed fluctuations; at the same time, the meshing structure between the drive head 6 and the rivet 7's connecting groove 73 ensures that there is no slippage during power transmission, ensuring that the protrusions 75 on the end face of the rivet 7 can effectively rub and cut the composite material, providing power support for the effective cutting of the composite material.

[0037] The drive head 6 is connected to a rivet 7 at its end. The rivet 7 consists of a flange end 71 and a straight rod end 72. The flange end 71 is a large-diameter thin flange structure, which increases the contact area with the composite material plate.

[0038] Here, the large-diameter thin flange structure of flange end 71 can disperse the stress applied to the composite material side during the cross tensile test, and avoid the composite material from failing due to excessive local stress. At the same time, the thin flange structure can reduce the overall weight of rivet 7, avoid causing additional load on the composite material plate, and ensure the structural strength of the joint under the premise of lightweight.

[0039] A connecting groove 73 is provided on the flange end 71 for connecting to the end of the drive head 6.

[0040] Here, the connecting groove 73 is formed at the flange end 71 for engaging with the end of the drive head 6, and the connecting groove 73 is connected to the riveting groove 74 to form a channel through the rivet 7; the structure of the connecting groove 73 is adapted to the driving shape of the end of the drive head 6, specifically it can be set as torx type, torxplus type, internal plum blossom type or internal hexagonal type, to ensure stable power transmission between the drive head 6 and the rivet 7 and to avoid slippage during the riveting process.

[0041] Furthermore, the connecting groove 73 transmits rotational power by meshing with the drive head 6, ensuring that the rivet 7 rotates at high speed. On the other hand, during the riveting process, the composite material cutting material can be pushed upward into the connecting groove 73. The cutting material is squeezed and deformed by the polygonal or flower-shaped structure of the connecting groove 73 and stuck in the groove, preventing the cutting material from falling off, ensuring a neat appearance after riveting, and not occupying the interlocking space between the lower end of the rivet 7 and the metal plate, ensuring the effective contact area between the rivet 7 and the metal plate.

[0042] A riveting groove 74 for riveting is provided on the straight rod end 72. The connecting groove 73 is connected to the riveting groove 74. The cross-sectional shape of the riveting groove 74 is flared. The flared structure gradually expands from the connecting groove 73 to the end face of the nail leg. Its inner wall transitions smoothly without sharp edges.

[0043] Here, the riveting groove 74 facilitates the rivet 7 to pierce the metal plate under pressure, reduces the resistance of the metal plate to the rivet leg, and provides a smooth channel for the composite material to move upward, avoiding blockage or jamming of the material in the groove, ensuring that the material can smoothly enter the connecting groove 73, and reducing abnormal deformation of the rivet 7 caused by blockage of the material.

[0044] It is worth noting that the rivet leg is the area formed between the riveting groove 74 and the straight rod end 72, which is the key part for the rivet 7 to pierce the metal plate and achieve interlocking. Under the pressure of the riveting head 5, the rivet leg can pierce the metal plate and deform within the forming area of ​​the embedding groove 3. The length of the rivet leg is adapted to the total thickness of the combined plate to ensure that it can completely pierce the metal plate and leave enough deformation length.

[0045] Furthermore, as the core part of the rivet 7 that pierces the metal plate, the deformation of the rivet leg can form a locking zone with the metal plate to achieve mechanical interlocking. Moreover, the structural strength of the rivet leg can withstand the pressure during piercing and deformation, avoiding rivet leg breakage or excessive deformation, and ensuring the connection reliability of the joint.

[0046] The end face of the rivet 7 away from the flange end 71 is provided with a ring-shaped protrusion 75 for cutting. It has a micro-structure protrusion and concave shape, specifically a large number of small protrusions and concave teeth are evenly distributed. The height and spacing of the small teeth are adapted to the cutting requirements of composite materials, and can form a cutting effect similar to a grinding wheel when rotating.

[0047] Here, when the rivet 7 rotates at high speed, the bump 75 and the surface of the composite material plate are rubbed together to achieve cutting, which replaces direct punching, reduces defects such as cracking and delamination in the composite material cutting process, avoids fiber breakage and matrix damage caused by excessive punching force, and ensures the integrity of the cut surface of the composite material.

[0048] Working principle and usage process of this utility model: Preparation of composite material panels: Clean the surfaces of the composite material panels and metal plates to be connected in advance to remove oil, impurities, etc., to ensure that the connecting surfaces are clean and to avoid impurities affecting the riveting strength.

[0049] A: Material placement: Place the composite material plate as the upper layer and the metal plate as the lower layer, align them according to the preset riveting positions, and place them stably in the embedding groove 3 of the lower mold 2; ensure that the edge of the composite plate fits against the inner wall of the embedding groove 3 without obvious deviation, so as to provide an accurate position reference for subsequent riveting.

[0050] B: Pressing and fixing: Start the drive mechanism of the upper mold 1 to drive the pressure ring 4 to move downward until the lower surface of the pressure ring 4 is tightly attached to the upper surface of the composite material plate, pressing the combined plate tightly into the embedding groove 3; the pressing force is adapted to the strength of the composite material to avoid excessive pressure causing premature deformation or damage to the composite material plate, while ensuring that the combined plate does not shift in subsequent processes.

[0051] C: Rotary cutting: The external drive unit is activated, and the drive head 6 drives the rivet 7 to rotate at a preset speed at high speed, while applying downward feed pressure to the rivet 7; the microstructure bumps 75 on the end face of the rivet leg contact the surface of the composite material plate and generate friction, gradually cutting the composite material plate. There is no obvious fiber breakage or delamination during the cutting process; the rotary cutting continues until the rivet 7 completely cuts through the composite material plate, at which point the drive head 6 stops rotating.

[0052] D: Stamping and riveting: After the drive head 6 stops rotating, the pressure applied to the drive head 6 is immediately reduced to avoid interfering with the subsequent riveting action; then the drive mechanism of the riveting head 5 is started, so that the riveting head 5 slides down along the center clearance hole of the pressure ring 4 and applies vertical pressure to the flange end 71 of the rivet 7; under the action of pressure, the rivet leg of the rivet 7 pierces and embeds into the metal plate, and deforms under the guidance of the forming area of ​​the embedding groove 3, forming a tight mechanical interlock with the metal plate; during this process, the composite material material embedded in the riveting groove 74 of the rivet 7 is pushed upward until it is pushed to the position of the connecting groove 73 (inner drive cavity) of the rivet 7, and the material is squeezed and deformed and clamped due to the structure of the connecting groove 73.

[0053] E: Unloading: After the rivet 7 and the metal plate have fully formed a mechanical interlock, first control the rivet head 5 to reset upwards and disengage from the rivet 7; then control the pressure ring 4 to reset upwards and release the pressure on the assembly plate; finally control the drive head 6 to reset upwards and disengage from the connecting groove 73 of the rivet 7; ensure that the reset sequence of each component is reasonable and avoid collisions with the assembly plate or rivet 7 during the reset process, which could lead to damage to the joint.

[0054] Riveting effect inspection: Take out the assembled composite material plate and metal plate from the embedded groove 3 of the lower mold 2 and observe the appearance of the riveting part: there is no cracking, delamination or delamination on the composite material side, no obvious deformation on the metal plate side, the flange end 71 of the rivet 7 is tightly attached to the composite material plate, there is no detachment of the composite material material, and there is no loosening of the interlocking part between the rivet 7 and the metal plate, which meets the preset riveting quality requirements.

[0055] The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A rivet and device for riveting composite materials to metal plates, comprising an upper mold (1) and a lower mold (2), characterized in that: Also includes: An embedding groove (3) is provided at the end of the lower mold (2) for accommodating and engaging the plate material; A pressing ring (4) is fixedly installed on the upper mold (1) for pressing the plate. A rivet head (5) slides on the axis inside the central clearance hole of the pressing ring (4). A drive head (6) that is driven by an external drive unit is coaxially nested inside the pressing ring (4), and a rivet (7) is engaged at the end of the drive head (6).

2. A rivet and apparatus for riveting a composite material to a metal sheet according to claim 1, wherein: The rivet (7) consists of a flange end (71) and a straight rod end (72). The flange end (71) is provided with a connecting groove (73) for connecting with the end of the drive head (6). The straight rod end (72) is provided with a riveting groove (74) for riveting. The connecting groove (73) and the riveting groove (74) are connected.

3. A rivet and apparatus for riveting a composite material to a metal sheet according to claim 2, wherein: The cross-sectional shape of the riveting groove (74) is trumpet-shaped.

4. A rivet and apparatus for riveting a composite material to a metal sheet according to claim 3, wherein: The end face of the rivet (7) away from the flange end (71) is provided with a circumferential protrusion (75) for cutting.

5. A rivet and apparatus for riveting a composite material to a metal sheet according to claim 2, wherein: The flange end (71) is a large-diameter thin flange structure.

6. A rivet and apparatus for riveting a composite material to a metal sheet according to claim 1, wherein: The embedded groove (3) has a forming area corresponding to the position of the rivet (7). The shape of the forming area is adapted to the deformation shape of the end of the rivet (7) after piercing the metal plate, and is used to cooperate with the rivet to form a locking area.

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