Riveting die and riveting equipment

Abstract

The utility model relates to a riveting die and riveting equipment, the riveting die is used for the riveting equipment, the riveting die comprises a riveting die body, a cavity is formed in the top of the riveting die body, and the roughness of the bottom face of the cavity is larger than that of the top face of the riveting die body. The roughness of the bottom face of the cavity is set to be larger than that of the top face of the riveting die body, in the riveting process, materials of a low-ductility casting can enter the cavity, due to the fact that the roughness of the bottom face of the cavity is large, the material fluidity of the low-ductility casting can be reduced, and therefore the problem of riveting buckle cracks is effectively reduced or even completely eliminated.

Description

Technical Field

[0001] The present disclosure relates to the technical field of riveting, and in particular to a riveting die and a riveting device. Background Art

[0002] SPR (Self Piercing Riveting, referred to as SPR), that is, self-piercing riveting or self-puncture riveting, is a cold connection technology in which the rivet rod penetrates the rivet into two or more layers of sheet metal at a certain pressure and speed, and the rivet and the sheet metal form an interlocking state under the support and restriction of the riveting die.

[0003] New energy vehicles use more and more die-cast parts. For example, die-cast aluminum alloys such as shock towers and rear floors generally have low ductility, so they are prone to cracking during SPR connection. In related technologies, the rivet die adopts an annular groove structure to alleviate the cracking problem of the rivet buckle during the riveting process, but cracks are still inevitable. Utility Model Content

[0004] The purpose of the present disclosure is to provide a riveting die and a riveting device, which can effectively reduce or even completely eliminate the problem of rivet button cracks, so as to at least partially solve the related technical problems.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present disclosure provides a rivet die, including a rivet die body, a cavity is formed on the top of the rivet die body, and the roughness of the bottom surface of the cavity is greater than the roughness of the top surface of the rivet die body.

[0006] Optionally, the mold cavity includes cavity one and cavity two which is arranged on the bottom surface of cavity one and is recessed in a direction away from the top surface of the rivet mold body, and the bottom surfaces of cavity one and cavity two are formed with anti-slip structures for reducing the fluidity of materials entering cavity one and cavity two during the riveting process.

[0007] Optionally, the cavity one and the cavity two are coaxially arranged.

[0008] Optionally, the depth of the second cavity is smaller than the depth of the first cavity.

[0009] Optionally, the side wall of the cavity one is constructed to gradually tilt outward from the bottom surface of the cavity one toward the top surface of the rivet mold body, and the side wall of the cavity one is also formed with the anti-slip structure.

[0010] Optionally, the angle between the side wall and the top surface of the cavity 1 is less than or equal to 45°.

[0011] Optionally, a chamfer or rounded transition is used at the junction of the side wall of the cavity one and the top surface of the rivet die body and / or at the junction of the side wall of the cavity one and the side wall of the cavity two.

[0012] Optionally, the anti-slip structure is constructed as a mesh pattern, tooth-like protrusions or a leather grain molding structure.

[0013] Optionally, the rivet die further includes a connecting column connected to the bottom of the rivet die body.

[0014] According to a second aspect of the present disclosure, a riveting device is further provided, and the riveting device includes the riveting die provided in the first aspect of the present disclosure.

[0015] Through the above technical solution, that is, the rivet die disclosed in the present invention, a cavity is formed on the top surface of the rivet die body, and the roughness of the bottom surface of the cavity is set to be greater than the roughness of the top surface of the rivet die body. During the riveting process, the material of the low-ductility casting will enter the cavity. Since the roughness of the bottom surface of the cavity is relatively large, the material fluidity of the low-ductility casting can be reduced, thereby effectively reducing or even completely eliminating the problem of rivet cracks.

[0016] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0018] Figure 1 It is a structural diagram of a rivet mold provided in some embodiments of the present disclosure.

[0019] Figure 2 is a top view of a rivet die provided in some embodiments of the present disclosure.

[0020] Figure 3 is a side view of a rivet die provided in some embodiments of the present disclosure.

[0021] Figure 4 is based on Figure 3 AA section view in.

[0022] Figure 5 is based on Figure 4 Enlarged view of part B in .

[0023] Figure 6 It is a schematic diagram of the microstructure of the connection between the anti-slip structure of the rivet mold and the material in some embodiments of the present disclosure.

[0024] Description of Reference Numerals

[0025] 100 - rivet mold body; 101 - top surface; 110 - mold cavity; 111 - cavity one; 111a - bottom surface of cavity one; 111b - side wall of cavity one; 112 - cavity two; 112a - bottom surface of cavity two; 200 - anti-slip structure; 300 - connecting column; 310 - installation and fixing part. DETAILED DESCRIPTION

[0026] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0027] In the present disclosure, unless otherwise stated, the directional words used, such as "top" and "bottom", refer to the top and the bottom of the corresponding drawings; "inside" and "outside" refer to the inside and outside of the outline of the corresponding component; "far" and "near" refer to the distance between the corresponding structure and the corresponding component and the distance between the corresponding structure and the corresponding component and the distance between the corresponding structure and the corresponding component and the corresponding component. In addition, the terms "first", "second", etc. used in the present disclosure are to distinguish one element from another and do not have order and importance. In addition, in the following description, when referring to the drawings, unless otherwise explained, the same figure numbers in different drawings represent the same or similar elements. The above definitions are only used to explain and illustrate the present disclosure and should not be construed as limitations on the present disclosure.

[0028] New energy vehicles are in a period of rapid development, but due to the increase in the overall weight of the vehicle body caused by the battery pack, we can only continue to look for lightweight solutions from the white body structure, and lightweighting of vehicles has always been an eternal theme. Lightweighting of vehicles is to reduce the weight of the vehicle body as much as possible while maintaining the strength and safety performance of the vehicle. The steel-aluminum hybrid body structure is a perfect interpretation of the concept of "using the right material in the right place". In July 2019, Tesla released a new patent "Multi-directional body integrated molding casting machine and related casting method for automobile frames". In 2020, Tesla applied one-piece die-casting technology to the Model Y rear floor assembly for the first time, and applied large castings that do not require heat treatment (hereinafter referred to as large castings) to the whole vehicle for the first time, which promoted the process change of body manufacturing. It can be called an industrial revolution in automobile manufacturing. More and more car companies are beginning to use large castings as part of the body structure.

[0029] Traditional die-cast aluminum alloys, such as shock towers, are generally made of AlSi10MnMg material and are heat treated at T6 or T7 to ensure that the material can obtain a good ductility of ≥12%. Although large castings reduce the number of body parts and reduce weight, the disadvantages are also obvious: the castings are too large and are thin-walled high-pressure cast aluminum alloys, which cannot be heat treated, which will cause the part size to deform too much and fail to meet the body assembly requirements. Since secondary heat treatment is not possible, the ductility of large castings that do not require heat treatment is generally low. It is already very good to be able to achieve more than 6%, and even the elongation of some special positions is about 2%. Such low ductility makes large castings prone to cracking when SPR connections are made.

[0030] In the related art, a ring-shaped concave bottom die is provided to reduce or even eliminate the problem of cracks at the bottom of the rivet buckle during SPR connection. However, after actual use, it was found that there were still many tiny cracks around the appearance of the SPR rivet buckle. Although no through cracks appeared, for large castings, it also affected the appearance quality of the large castings.

[0031] In order to achieve the above purpose, Figures 1 to 6 As shown, an embodiment of the present disclosure provides a riveting die, which includes a riveting die body 100 , a cavity 110 is formed on the top of the riveting die body 100 , and the roughness of the bottom surface of the cavity 110 is greater than the roughness of the top surface 101 of the riveting die body 100 .

[0032] Through the above technical solution, that is, the rivet die disclosed in the present invention, a cavity 110 is formed on the top surface 101 of the rivet die body 100, and the roughness of the bottom surface of the cavity 110 is set to be greater than the roughness of the top surface 101 of the rivet die body 100. During the riveting process, the material of the low-ductility casting will enter the cavity 110. Since the roughness of the bottom surface of the cavity 110 is relatively large, the material fluidity of the low-ductility casting can be reduced, thereby effectively reducing or even completely eliminating the problem of rivet cracks.

[0033] In order to avoid riveting, for example, the roughness of the bottom surface of the cavity 110 can be greater than Ra3.2, or greater than Ra6.3 or Ra12.5, etc., as long as it is rough enough to reduce the flow of the material in contact with it. It can be understood that the roughness of the bottom surface of the cavity 110 can increase the flow of the material entering the cavity 110 and restricting or restraining the bottom surface. Compared with a relatively smooth surface, the rougher the contact surface, the greater the impact on the flow performance of the material, thereby reducing material stretching and reducing or avoiding cracks.

[0034] like Figure 1 , Figure 4 and Figure 5As shown, in some embodiments, the mold cavity 110 includes a cavity 111 and a cavity 112 which is provided on a bottom surface 111a of the cavity 111 and is recessed toward a direction away from a top surface 101 of the rivet mold body 100. The bottom surface 111a of the cavity 111 and the bottom surface 112a of the cavity 112 are formed with an anti-slip structure 200 for slowing down the fluidity of the material entering the cavity 111 and the cavity 2 112 during the riveting process.

[0035] The diameter of cavity 111 can be larger than the diameter of the rivet, and the diameter of cavity 2 112 can be equal to or slightly smaller than the diameter of the rivet. Since the riveting die is on the side opposite to the riveting punch during riveting, cavity 111 can accommodate the deformation of the underlying material (such as a large casting) to form a rivet, and can avoid the circumferential flow of the material to a certain extent. At the same time, a cavity 2 112 that is concave downward is formed on the bottom surface 111a of cavity 111 to accommodate part of the material in cavity 111 during the riveting process, so as to avoid excessive increase in riveting force due to metal filling cavity 111. At the same time, the circumferential flow of the material can be reduced to a certain extent, further reducing the material flow. In this embodiment, an anti-slip structure 200 is provided on the bottom surface 111a of cavity 111 and the bottom surface 112a of cavity 2 112, so that after contacting with the material, it can form resistance to the flow of the material, so that the material produces minimal deformation in the local space of the surface, thereby reducing the generation of cracks during the riveting process.

[0036] The anti-slip structure 200 can be constructed with any suitable structure to at least increase the roughness of the bottom surface of the cavity 110 and reduce the flow performance of the material. In some embodiments, the anti-slip structure 200 can be constructed as a mesh, tooth-like protrusions, or a leather-spun structure formed by leather grain processing.

[0037] It should be noted that the anti-skid structure 200 may be a mesh pattern arranged on the bottom surface 111a of the first cavity 111 and the bottom surface 112a of the second cavity 112, i.e., a mesh pattern, for example, a mesh protrusion or a mesh depression, to increase the roughness of the bottom surface. In addition, the anti-skid structure 200 may also be a tooth-like protrusion formed on the bottom surface, and when the material contacts the bottom surface, a rougher bottom surface is formed by the tooth-like protrusion, which reduces the flow of the material and prevents it from being deformed too much and causing cracks.

[0038] It is understandable that the anti-slip structure 200 may also be formed with a leather grain structure on the bottom surface by adopting a special leather grain processing process, which has the effect of increasing the bottom surface roughness and reducing material flow.

[0039] A special leather grain treatment process is used to make the microstructure of the inner cavity of the rivet mold present an irregular texture, so that the large casting material flows in the serrated space of each local area, and the serrated microstructure effectively restricts the flow of the material, thus achieving the effect of preventing the occurrence of SPR rivet cracks. Figure 6 As shown in the figure, the lower serrated profile represents the microstructure of the bottom surface of the cavity 110 of the riveting die, and the upper serrated profile represents the casting plate during riveting. During riveting, the microstructure can bite with the casting plate to reduce the generation of cracks by reducing its radial flow.

[0040] Through the above arrangement, the anti-slip structure 200 is formed on the bottom surface 111a of the cavity 111 and the bottom surface 112a of the cavity 2 112, which can reduce the material fluidity of the large casting with low ductility, so that the use of the riveting die during SPR riveting of the large casting without heat treatment can effectively reduce or even completely eliminate the rivet crack problem.

[0041] It should be noted that, based on the low elongation characteristics of large castings, it is necessary to effectively control the occurrence of cracks and ensure that the interlocking, remaining plate thickness and head height requirements that can be achieved by the SPR connection can be achieved, so that the material can meet the quality requirements with minimal flow. Therefore, the depth of the cavity 111 of the cavity 110 of the riveting mold needs to be precisely controlled.

[0042] The second cavity 112 of the cavity 110 allows the SPR rivet to open its legs better when piercing a large casting, thereby forming an effective interlock. Depending on the length of the nail and the material of the top plate, the interlock can be at least 0.2 mm. At the same time, the depth of the second cavity 112 must also be effectively controlled, otherwise cracks will appear in the second cavity 112 due to insufficient elongation of the material.

[0043] At the same time, since large castings are formed by casting, common defects in the form of strips or dots are usually formed on their surfaces. Since the cavity 110 of the rivet die of this embodiment adopts the above-mentioned anti-slip structure 200, during the riveting process, the rivet die cooperates with the punch and rivet of the riveting equipment to reshape the surface of the large casting, so that common defects on the surface of the large casting can be partially repaired, effectively improving the appearance surface quality of the large casting.

[0044] like Figure 2 and Figure 4 As shown, in some embodiments, cavity one 111 and cavity two 112 are coaxially arranged. Wherein, cavity one 111 and cavity two 112 both adopt a circular structure or a structure approximately circular, and the central axis of the two coincides, that is, the projections of the two on the plane where the top surface 101 of the rivet die body 100 is located are two concentric circles, so that the material of cavity one 111 flows into cavity two 112 during the riveting process, and can be accumulated in the middle area, and avoids flowing in the circumferential direction (radial direction), thereby reducing the generation of cracks.

[0045] In some embodiments, the depth of cavity 2 112 is less than the depth of cavity 1 11. The depth of cavity 1 11 can be set according to actual needs, including the number of layers and thickness of the riveted material. The depth of cavity 2 112 should be less than the depth of cavity 1 11, which can make the rivet legs open and form better and interlock better on the one hand; on the other hand, it can also accommodate the accumulation of materials in the center to avoid radial flow and cracks.

[0046] In order to avoid the transition of the bottom material layer during riveting at the junction of the top surface 101 of the riveting die body 100 and the cavity 111, Figure 4 and Figure 5 As shown, in some embodiments, the side wall 111b of the cavity 111 is constructed to gradually tilt outward from the bottom surface of the cavity 111 toward the top surface 101 of the rivet mold body 100, and the side wall 111b is also formed with an anti-slip structure 200. Among them, the side wall 111b of the cavity 111 adopts a bevel transition, which can reduce the transition drawing of the casting material at the side, and can ensure the effective molding and filling of the material in the cavity 110 of the rivet mold, so that the large casting flow material is completely attached to the cavity 110 of the rivet mold, preventing the SPR rivet buckle from cracking due to excessive local tensile stress.

[0047] In some embodiments, the angle C between the side wall 111b of the cavity 1 and the top surface 101 is less than or equal to 45°. For example, it can be 45°, 30°, etc., or even smaller. This configuration allows the side wall to tilt outward at a larger angle, further reducing transition drawing, and providing a certain support for the material. The side wall is also provided with the above-mentioned anti-slip structure 200, further reducing cracks or avoiding the occurrence of cracks by reducing the flow properties of the material.

[0048] In order to avoid cracks at the corners of the mold cavity 110 due to the existence of sharp corners, in some embodiments, the junction of the side wall 111b of the cavity 1 and the top surface 101 of the rivet mold body 100 and / or the junction of the side wall and the side wall of the cavity 2 112 is chamfered or rounded. The size of the chamfer and rounded corners can be appropriately designed according to the diameter and depth of the cavity 1 111 and the cavity 2 112, which will not be described in detail here.

[0049] like Figure 1 , Figure 3 and Figure 4As shown, in some embodiments, the rivet die needs to be fixed and positioned on the riveting device, so the rivet die also includes a connecting column 300 connected to the bottom of the rivet die body 100. The connecting column 300 is formed with a mounting and fixing portion 310 for connection, wherein the mounting and fixing portion 310 can be configured as a notch, and the specific structure can be designed with reference to the top screw on the riveting device, and can also be manufactured with reference to related technologies, which will not be repeated here.

[0050] The embodiment of the present disclosure also provides a riveting device, which includes a pressure head and a riveting die provided in the above embodiment of the present disclosure, and the pressure head and the riveting die are arranged on both sides of the multi-layer material piece to be riveted. Since the riveting device includes the above riveting die, it also has all the advantages of the above riveting die, which will not be described one by one here.

[0051] The riveting die and riveting equipment disclosed in the present invention form a cavity 110 on the top surface 101 of the rivet die body 100, and the roughness of the bottom surface of the cavity 110 is set to be greater than the roughness of the top surface 101 of the rivet die body 100. During the riveting process, the material of the low-ductility casting will enter the cavity 110. Since the roughness of the bottom surface of the cavity 110 is relatively large, the material fluidity of the low-ductility casting can be reduced, thereby effectively reducing or even completely eliminating the problem of rivet cracks.

[0052] At the same time, actual riveting experiments have shown that the casting itself has tensile defects on its surface. After using the rivet die for SPR connection, there is no visible tensile defect on the surface of the SPR rivet buckle. That is, the rivet die can also reshape the surface of the large casting, so that ordinary defects on the surface of the large casting can be at least partially repaired, effectively improving the appearance surface quality of the large casting.

[0053] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0054] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0055] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A riveting die, comprising a riveting die body, wherein a cavity is formed at the top of the riveting die body, characterized in that: The roughness of the bottom surface of the cavity is greater than the roughness of the top surface of the rivet die body.

2. The riveting die according to claim 1, characterized in that: The mold cavity includes cavity one and cavity two which is arranged on the bottom surface of cavity one and is recessed in a direction away from the top surface of the rivet mold body. The bottom surfaces of cavity one and cavity two are formed with anti-slip structures for reducing the fluidity of materials entering cavity one and cavity two during riveting.

3. The riveting die according to claim 2, characterized in that: The cavity one and the cavity two are coaxially arranged.

4. The riveting die according to claim 2, characterized in that: The depth of the second cavity is smaller than the depth of the first cavity.

5. The riveting die according to claim 2, characterized in that: The side wall of the cavity one is constructed to gradually tilt outward from the bottom surface of the cavity one toward the top surface of the rivet mold body, and the side wall of the cavity one is also formed with the anti-slip structure.

6. The riveting die according to claim 5, characterized in that: The angle between the side wall and the top surface of the cavity 1 is less than or equal to 45°.

7. The riveting die according to claim 5, characterized in that: The junction between the side wall of the cavity one and the top surface of the rivet die body and / or the junction between the side wall of the cavity one and the side wall of the cavity two adopts chamfering or rounded transition.

8. The riveting die according to any one of claims 2 to 7, characterized in that: The anti-slip structure is constructed as a mesh pattern, tooth-shaped protrusions or a leather pattern forming structure.

9. The riveting die according to claim 1, characterized in that: The riveting die also includes a connecting column connected to the bottom of the riveting die body.

10. A riveting device, characterized in that: The riveting equipment comprises the riveting die according to any one of claims 1-9.

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