Punch

Abstract

The present invention provides a punch for punching rivets. The rivet is provided with a punching hole surrounded by a peripheral wall at at least one end. The punch includes a tapered portion and a main body having an end face. The end face surrounds and is connected to the bottom end of the tapered portion with a larger diameter. The diameter of the bottom end of the tapered portion is larger than the initial inner diameter of the punching hole of the rivet. As the tapered portion is pressed into the punching hole of the rivet, the peripheral wall can extend radially outward and eventually press against the end face of the main body. The punch according to the present invention can 1) increase the clamping force between the riveted parts to avoid loosening between these parts; 2) inhibit or avoid cracking of the rivet head after being punched; and 3) make the size and shape of the rivet head obtained after punching uniform, and increase the service life and strength of the rivet head.

Description

Technical Field

[0001] The invention relates to a punch, in particular to a punch used for punching a rivet with a punch hole to realize riveting. Background Art

[0002] Figure 1A , Figure 1B and Figure 1C The following are perspective view, longitudinal section view and top view of a rivet. The main body 1 of the rivet is generally cylindrical. Both ends of the main body 1 are provided with punching holes 10. Figure 1B As shown, exemplary dimensions of such a rivet are as follows: body outer diameter a=4 mm, punch diameter b=2 mm, punch depth c=4.5 mm, and rivet length L=14.5 mm.

[0003] When the punching hole 10 of the rivet is punched by a punch, the peripheral wall 11 of the punching hole 10 is deformed outwardly along the radial direction of the main body 1, and in particular, the peripheral wall 11 at the end of the main body 1 is deformed outwardly due to the punching of the punch and forms a flange (i.e., a flanging), which is pressed tightly against the end edge of the rivet hole (the rivet hole is not shown in the figure) of the component to be riveted, thereby pressing the rivet into the rivet hole, thereby achieving riveting between the components. Therefore, this rivet is often used in situations where two or more components need to be riveted together.

[0004] Figure 2A and Figure 2B They are respectively a perspective view and a longitudinal cross-sectional view of a punch in the prior art. Figure 2A and Figure 2B The punch 2 shown has a cylindrical body 21 and a conical top 22. In the process of stacking and riveting a plurality of sheet parts together, the sheet parts are first stacked and rivets are placed in the concentrically arranged rivet holes of the sheet parts, and then the top 22 of the punch 2 is pressed into the punch hole 10 of the rivet, so that the peripheral wall 11 of the punch hole 10 is deformed outwardly as described above, and finally the sheet parts are riveted together.

[0005] However, the inventors have found that the use of such a punch 2 and riveting in the above manner results in at least one of the following disadvantages:

[0006] 1) The clamping force between the riveted sheet parts is insufficient. In other words, the riveted sheet parts are prone to loosening;

[0007] 2) The rivet head (e.g. the peripheral wall 11 at the end of the rivet described above) is prone to cracking after being punched;

[0008] 3) Although the specifications of the rivets used are the same, after the riveting operation is completed using the above punch and riveting method, the sizes and shapes of the different rivet heads obtained are uneven, which has an adverse effect on subsequent processing; and

[0009] 4) The service life and strength of the rivet head are reduced. Summary of the invention

[0010] The inventors have made the present invention to overcome at least one of the above disadvantages.

[0011] The present invention provides a punch for punching a rivet. The rivet is provided with a punching hole surrounded by a peripheral wall at at least one end. The punch comprises a tapered portion and a main body having an end face. The end face surrounds and is connected to the bottom end of the tapered portion with a larger diameter. The diameter of the bottom end of the tapered portion is larger than the initial inner diameter of the punching hole of the rivet. As the tapered portion is pressed into the punching hole of the rivet, the peripheral wall extends radially outward and presses against the end face of the main body.

[0012] In addition, the diameter of the bottom end of the tapered portion may be slightly smaller than, equal to, or slightly larger than the initial outer diameter of the peripheral wall of the rivet.

[0013] A groove is provided at the connection between the bottom end of the tapered portion and the end surface of the main body.

[0014] Observed along the axial direction of the tapered portion, the initial outer diameter of the peripheral wall of the rivet may be slightly larger than the outer diameter of the groove, or between the outer diameter and the inner diameter of the groove.

[0015] The groove is concave relative to the side surface of the tapered portion and the end surface of the main body.

[0016] The groove may have a circular arc cross-sectional profile, wherein the radius of the circular arc is 5% to 10% of the wall thickness of the peripheral wall of the rivet.

[0017] The cone apex angle of the conical portion is 90° to 150°, and more specifically, the cone apex angle of the conical portion is 120°.

[0018] The conical portion is a truncated conical portion, a diameter of a top surface of the truncated conical portion is smaller than an initial inner diameter of the punched hole of the rivet, and a height of the truncated conical portion is smaller than a depth of the punched hole of the rivet. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to facilitate the understanding of the present invention, the present invention is described in more detail below based on exemplary embodiments and in conjunction with the accompanying drawings. The same or similar reference numerals are used in the accompanying drawings to represent the same or similar components. It should be understood that the accompanying drawings are only schematic, and the sizes and proportions of the components in the accompanying drawings are not necessarily accurate.

[0020] Figure 1A , Figure 1B and Figure 1C They are respectively a perspective view, a longitudinal section view and a top view of a rivet.

[0021] Figure 2A and Figure 2B They are respectively a perspective view and a longitudinal cross-sectional view of a punch in the prior art.

[0022] Figure 3A and Figure 3B 1 and 2 are a perspective view and a longitudinal sectional view, respectively, of a punch according to an embodiment of the present invention.

[0023] Figure 3C yes Figure 3B Magnified view of area 3C.

[0024] Figure 3D yes Figure 3C Further zoomed-in view of the area in 3D.

[0025] Figure 4A This is a longitudinal sectional view showing a state in which a rivet is punched using the punch according to the present invention.

[0026] Figure 4B yes Figure 4A Magnified view of area 4B.

[0027] Figure 4C yes Figure 4B Further magnification of area 4C. DETAILED DESCRIPTION

[0028] Reference has been made to the “Background Technology” section above. Figures 1A to 2B The details of the rivet and punch in the prior art are described in detail, so they will not be repeated in the following. FIG. 3A to FIG. 4C A punch according to an embodiment of the present invention will be described.

[0029] Figure 3A and Figure 3B 1 and 2 are a perspective view and a longitudinal sectional view, respectively, of a punch according to an embodiment of the present invention.

[0030] like Figure 3A and Figure 3BAs shown, the punch 3 mainly includes a main body 31, a tapered portion 32 and a circular (annular) end face 33. The tapered portion 32 can be generally conical. The end face 33 is located at one end of the main body 31. In this example, the main body 31 is cylindrical. However, it can be understood by those skilled in the art that the main body 31 can also be in any other shape as long as the main body 31 has an end face 33. The tapered portion 32 is located at the center of the end face 33 and gradually protrudes from the end face 33 along the axial direction of the main body 31.

[0031] Figure 4A It is a longitudinal cross-sectional view showing a state when a rivet is punched using the punch 3 . Figure 4B yes Figure 4A Magnified view of area 4B. Figure 4C yes Figure 4B Further magnification of area 4C.

[0032] The diameter of the bottom end of the tapered portion 32 is larger than the initial inner diameter (i.e., the inner diameter before deformation) b of the punch hole 10 of the rivet, so that as the tapered portion 32 is pressed into the punch hole 10, the peripheral wall 11 of the punch hole 10 extends radially outward and finally presses against the end face 33 of the punch 3, as shown in FIG. FIG. 4A to FIG. 4C Thus, when the punch 3 is used to apply pressure to the punch hole 10, the peripheral wall 11 of the punch hole 10 is subjected to pressure from the side surface of the tapered portion 32 as in the prior art, and is also subjected to pressure from the end surface 33 of the punch 3 at the end of the punching process.

[0033] Specifically, if Figure 4B and Figure 4C As shown, the flange 12 (i.e., the flanging) formed by the peripheral wall 11 of the punch hole 10 of the rivet extending outward due to the punching of the punch 3 is also subjected to the pressure applied by the end face 33 of the punch 3 at the end of the punching process. As a result, the flange 12 is firmly pressed against the end edge of the rivet hole (the rivet hole is not shown in the figure) of the riveted component. Therefore, by using the punch 3 disclosed in the present invention to perform a punching process on the rivet, the pressing force between the riveted components can be increased to prevent the riveted components from loosening.

[0034] In addition, if FIG. 3A to FIG. 3D As shown, an annular groove 34 may be provided along the circumference of the bottom end of the tapered portion 32. Observed along the axial direction of the tapered portion 32, the groove 34 has an outer diameter and an inner diameter. The outer diameter of the groove 34 is the diameter of the circle corresponding to the outer edge of the groove 34. The inner diameter of the groove 34 is the diameter of the circle corresponding to the inner edge of the groove 34. The initial outer diameter a of the peripheral wall 11 of the punching hole 10 of the rivet (i.e., the outer diameter before deformation) is slightly larger than the outer diameter of the groove 34, or between the outer diameter and the inner diameter of the groove 34.

[0035] Specifically, if Figure 3C and Figure 3D As shown, the groove 34 may have an arc-shaped cross-sectional profile, and the radius R of the arc-shaped cross-sectional profile may be 5% to 10% of the wall thickness of the peripheral wall 11 of the rivet to be punched. In one example, the wall thickness of the peripheral wall 11 of the rivet to be punched is 1 mm, the distance r of the center O of the arc-shaped cross-sectional profile from the axis of the punch 3 (i.e., the axis of the tapered portion) is 2 mm, and the distance h from the end face 33 of the punch 3 is 0.1 mm, and the radius R of the arc-shaped cross-sectional profile is 0.05 mm to 0.1 mm.

[0036] In the later stage of punching the rivet using the punch 3 of the present invention, the peripheral wall 11 of the punch hole 10 of the rivet is extended outward due to the punching of the punch 3 and forms a flange 12, and the flange 12 reaches the groove 34. At this time, the groove 34 can play a buffering role (that is, allowing the flange 12 to deform in the groove 34) and a guiding role for the material forming the flange 12, so that the flange 12 is smoothly deflected and deformed toward the end face 33 of the punch 3 along the groove 34, and finally forms a rivet head with uniform shape and size.

[0037] On the other hand, the inventors have found that if the groove 34 is not provided, the flange 12 cannot be smoothly deflected and deformed toward the end face 33 of the punch 3 in some cases, but is bent and accumulated at the bottom circumference of the tapered portion 32, that is, at the intersection of the tapered portion 32 and the end face 33. As a result, the shape and size of the rivet head finally formed may be uneven, or even cracked, and a sufficiently large pressing force between the riveted parts cannot be ensured.

[0038] like Figure 3C and Figure 3D As shown in the figure, a part of the groove 34 is opened on the side surface of the tapered portion 32, and another part of the groove 34 is opened on the end surface 33 of the punch 3. In other words, the groove 34 is concave relative to the side surface of the tapered portion 32 and the end surface 33. The inventor has found that, in the case of adopting such a structure, it is beneficial for the flange 12 to smoothly deflect and deform along the groove 34 toward the end surface 33 of the punch 3.

[0039] On the other hand, Figure 3C As shown, the cone vertex angle of the cone portion 32 may be 90° to 150°, and preferably 120°. Those skilled in the art will appreciate that the cone vertex angle of the cone portion 32 may be appropriately selected according to actual needs.

[0040] In both cases where the groove 34 is provided and where the groove 34 is not provided, the diameter of the bottom end of the tapered portion 32 may be slightly smaller than or equal to the initial outer diameter a of the peripheral wall 11 of the punch hole 10 of the rivet, or slightly larger than the initial outer diameter a of the peripheral wall 11 of the punch hole 10. In this way, it is ensured that the flange 12 formed by the peripheral wall 11 can be pressed against the end face 33 of the punch 3 at the later stage of the punching process of the rivet using the punch 3, in other words, it is ensured that the end face 33 of the punch 3 can apply pressure to the flange 12.

[0041] On the contrary, it can be understood that if the diameter of the bottom end of the tapered portion 32 is much larger than the initial outer diameter a of the peripheral wall 11 of the punch hole 10 of the rivet, then at the later stage of the punching process of the rivet using the punch 3, the flange 12 may not be sufficient to extend to the end face 33 of the punch 3, resulting in the end face 33 (and the groove 34) being unable to function, thereby losing the meaning of setting the end face 33 (and the groove 34).

[0042] like FIG. 3A to FIG. 3D As shown, the conical portion 32 may be a truncated conical portion, that is, a truncated cone. The diameter of the top surface of the truncated conical portion is smaller than the initial inner diameter b of the punching hole 10 of the rivet, and the height of the truncated conical portion is smaller than the depth c of the punching hole 10 of the rivet (see Figure 1B ). In this way, it is beneficial for the tapered portion 32 to be smoothly pressed into the punching hole 10 of the rivet for riveting.

[0043] The technical objectives, technical solutions and technical effects of the present invention are described in detail with reference to specific embodiments. It should be understood that the above embodiments are exemplary only and not restrictive. Within the spirit and principles of the present invention, any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art are included in the protection scope of the present invention.

Claims

1. A punch for punching a rivet, wherein the rivet is provided with a punching hole surrounded by a peripheral wall at at least one end, the punch comprising a conical portion and a main body having an end face, the conical portion having a cone vertex angle of 90° to 150°, the end face surrounding and connected to a bottom end of the conical portion with a larger diameter, and the diameter of the bottom end of the conical portion is larger than an initial inner diameter of the punching hole of the rivet, so that as the conical portion is pressed into the punching hole of the rivet, the peripheral wall extends radially outward and presses against the end face of the main body, and a groove is provided at the connection between the bottom end of the conical portion and the end face of the main body, in, The groove is concave relative to the side surface of the tapered portion and the end surface of the main body. The groove has a circular arc cross-sectional profile, and The radius of the arc-shaped cross-sectional profile is 5% to 10% of the wall thickness of the peripheral wall of the rivet.

2. The punch according to claim 1, wherein: The diameter of the bottom end of the tapered portion is slightly smaller than, equal to, or slightly larger than the initial outer diameter of the peripheral wall of the rivet.

3. The punch according to claim 1, wherein: Observed along the axial direction of the tapered portion, the initial outer diameter of the peripheral wall of the rivet is slightly larger than the outer diameter of the groove, or is between the outer diameter and the inner diameter of the groove.

4. The punch according to claim 1, wherein: The cone apex angle of the cone portion is 120°.

5. The punch according to claim 1, wherein: The conical portion is a truncated conical portion, a diameter of a top surface of the truncated conical portion is smaller than an initial inner diameter of the punched hole of the rivet, and a height of the truncated conical portion is smaller than a depth of the punched hole of the rivet.

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