Self-perforating rivets

Abstract

This invention provides a self-perforating rivet that can hold the piece of the fastened object generated during fastening when the self-perforating rivet has a through hole, and is easy to manufacture, as well as a fastening method using the same. [Solution] A self-perforating rivet having a through hole in the axial direction, comprising a flange portion having an opening for the through hole and a tubular portion extending from the flange portion, wherein a protrusion is formed on the surface of the flange portion along the opening, and in the upper plate to which the fastened object is fastened by the self-perforating rivet, the protrusion is flattened while the opening is reduced in diameter. With the above self-perforating rivet, it is possible to prevent the fastened object piece generated during fastening from coming out of the opening on the surface of the flange portion. Furthermore, preferably, a locking portion with a reduced inner diameter for locking the fastened object piece may be formed on the inner wall of the tubular portion of the self-perforating rivet. This locking portion prevents the fastened object piece from falling out in the direction of the leg portion.

Description

Technical Field

[0001] This specification relates to a self-piercing rivet. In particular, it relates to a self-piercing rivet that holds the fastened object pieces after fastening.

Background Art

[0002] Conventional self-piercing rivets include a tubular part and a flange part provided at one end of the tubular part, and fasten a plurality of stacked fastened objects without penetrating them. The fastening of this conventional self-piercing rivet is performed as follows as an example. That is, when the self-piercing rivet is driven into the upper plate and the lower plate placed on the die using a punch, the leg part of the self-piercing rivet penetrates the upper plate. The tip of the tubular part of the self-piercing rivet that has penetrated the upper plate is further driven into the lower plate. When the lower surface of the lower plate contacts the bottom of the die, the bottom of the die pushes the lower plate back. The tubular part of the self-piercing rivet receives a reaction force from the lower plate, and the leg part is distorted so that the diameter expands from the tip inside the lower plate, and an interlock is formed, thereby fastening the upper plate and the lower plate. Then, the die and the punch are removed from the fastened object, and the fastening is completed. Further, the fastened object can further include a plurality of fastened objects between the upper plate and the lower plate.

[0003] Conventional self-piercing rivets generally use a method that does not penetrate the lower plate. However, when considering a method of penetrating the lower plate, the fastened object pieces generated when the self-piercing rivet penetrates the fastened object may come out of the through-hole and cause foreign matter contamination.

[0004] In addition, among conventional self-piercing rivets, there are self-piercing rivets provided with grooves or notch parts so that the fastened object pieces do not fall, but there is a difference in strength depending on the position of the grooves or notch parts after fastening. In some cases, force concentrates on the grooves or notch parts, and the leg part of the self-piercing rivet may be damaged.

[0005] For example, Patent Document 1 discloses a method of fastening a self-perforating rivet having a through hole with an annular groove in the inner wall near the flange portion, while holding the fastened piece, by using a special punch that deforms the fastened piece along the annular groove.

[0006] The method described in Patent Document 1 is based on the premise of using a special punch, and when a general punch is used, it is not possible to hold the piece to be fastened. Furthermore, depending on the shape of the piece to be fastened, the method in Patent Document 1 may not deform along the annular groove, and it is conceivable that the piece to be fastened may not be able to be held.

[0007] Furthermore, the self-perforating rivet described in Patent Document 1 is difficult to manufacture by pressing due to the presence of an annular groove in the through hole, making it unsuitable for mass production.

[0008] Therefore, there was a need for a self-perforating rivet that could hold the fastened object pieces generated during fastening when the self-perforating rivet has a through hole in the flange portion, and that could also be press-formed. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Special table number 2015-522425 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The object of the present invention is to provide a self-perforating rivet that can hold the piece of the fastened object generated during fastening when the self-perforating rivet has a through hole, and that is easy to manufacture (can be manufactured by cold forging), and a method for fastening the same. [Means for solving the problem]

[0011] To solve the above problems, one aspect of the present invention is a self-perforating rivet having a through hole in the axial direction, comprising a flange portion having an opening for the through hole and a tubular portion extending from the flange portion, wherein a protrusion is formed on the surface of the flange portion along the opening, and in the upper plate to which the object to be fastened is fastened by the self-perforating rivet, the protrusion is crushed while the opening is reduced in diameter. With the above self-perforating rivet, it is possible to prevent pieces of the object to be fastened that are generated during fastening from coming out through the opening on the surface of the flange portion.

[0012] Preferably, a locking portion with a reduced inner diameter may be formed on the inner wall of the tubular portion of the self-perforating rivet to secure the fastened piece. This locking portion prevents the fastened piece from falling out in the direction of the leg portion.

[0013] Preferably, the outer shape of the convex shape formed along the opening of the through hole on the surface of the flange portion can be any shape, such as a polygon, not just a circle.

[0014] Preferably, the protrusions of the self-perforating rivet can form one or more partial protrusion shapes.

[0015] Another aspect of the present invention is a method of fastening objects using a self-perforating rivet having an axial through hole, wherein the self-perforating rivet has a flange portion having a through-hole opening, a tubular portion extending from the flange portion, and a leg portion extending from the tubular portion on the opposite side from the flange portion, with a protrusion formed on the surface of the flange portion along the opening of the through-hole, and when the self-perforating rivet is driven into the object to be fastened, the protrusion collapses and the opening shrinks in diameter, thereby holding the object to be fastened so that it does not slip out of the opening, and the leg portion expands in diameter, so that the flange portion and the leg portion clamp the object to be fastened.

[0016] Preferably, the above method is characterized by a locking portion with a reduced inner diameter formed on the inner wall of the tubular portion, which prevents pieces of the fastened object from falling out in the direction of the leg portion when the self-perforating rivet penetrates the fastened object.

[0017] Preferably, the above method can be a fastening method in which the surface of the flange portion of the fastened self-perforating rivet becomes flat.

[0018] According to the present invention, when the self-perforating rivet has a through hole, it is possible to provide a self-perforating rivet that can hold the piece of the object to be fastened that is generated during fastening, and that is easy to manufacture, as well as a fastening method using the same. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic diagram of a self-perforating rivet, which is one embodiment of the present disclosure. [Figure 2] This is a cross-sectional view of a self-perforating rivet, which is one embodiment of the present disclosure, in which a locking portion with a reduced inner diameter is formed on the inner wall of a tubular portion. [Figure 3] This is a modified example of the self-perforating rivet shown in Figure 1, in which the protrusion is formed in a polygonal shape, which is one embodiment of the present disclosure. [Figure 4] This is a modified example of the self-perforating rivet of Figure 1, having one or more partially convex shapes, which is one embodiment of the present disclosure. [Figure 5] This shows one embodiment of the present disclosure, in which a self-perforating rivet attached to a driving equipment and a fastening member installed on a die are set together. [Figure 6] This invention illustrates the process by which the tip of a self-perforating rivet penetrates the object to be fastened, as is one embodiment of the present disclosure. [Figure 7] This invention illustrates one embodiment in which the tip of a self-perforating rivet that has penetrated a workpiece comes into contact with a recess of a die, causing the protrusion to be crushed while the diameter of the opening is reduced. [Figure 8]This shows the process in which the tip of the self-piercing rivet, which is an embodiment of the present disclosure, is distorted along the concave portion of the die. [Figure 9] This shows the process in which the distorted leg portion and flange portion sandwich the object to be fastened, fastening the self-piercing rivet and the object to be fastened, which is an embodiment of the present disclosure. [Figure 10] This shows the state where the driving equipment and the die are removed and the fastening of the self-piercing rivet and the object to be fastened is completed, which is an embodiment of the present disclosure.

Mode for Carrying Out the Invention

[0020] [Configuration of Self-Piercing Rivet] FIG. 1 is a schematic view of a self-piercing rivet 100 according to an embodiment of the present disclosure. The self-piercing rivet 100 has a through hole in the axial direction. The self-piercing rivet 100 has a flange portion 102 having an opening of the through hole, a tubular portion 104 extending from the flange portion 102, and a leg portion 108 extending on the side opposite to the flange portion 102 with respect to the tubular portion 104. A convex portion 106 is formed on the surface of the flange portion 102 along the opening. As will be described later, the self-piercing rivet 100 is configured such that, in the state where the object to be fastened is fastened, the convex portion 106 is crushed while the opening diameter is reduced. By being configured in this way, when the self-piercing rivet 100 penetrates the object to be fastened, the piece of the object to be fastened generated from the object to be fastened is held so as not to come out of the opening, and when the leg portion 108 expands in diameter, the flange portion 102 and the leg portion 108 can sandwich the object to be fastened.

[0021] Note that the through hole of the self-piercing rivet may be tapered such that the inner diameter expands in the direction of the flange portion. By adopting such a shape, the space for holding the object to be fastened can be expanded.

[0022] In the embodiment of FIG. 1, since no grooves, locking portions, etc. are provided inside the through hole, swaging is possible.

[0023] Figure 2 is a cross-sectional view of a self-perforating rivet according to one embodiment of the present disclosure, in which a locking portion 201 with a reduced inner diameter for locking a piece of material to be fastened is formed on the inner wall of the tubular portion. The locking portion 201 prevents the piece of material to be fastened, which is generated from the material to be fastened, from falling out in the direction of the leg portion 108 when the self-perforating rivet 100 penetrates the material to be fastened.

[0024] In the embodiments shown in Figures 1 and 2, the inner wall of the through hole has a shape that is linear or expands in diameter from the locking portion 201 in the direction of the flange portion 102 and in the direction of the leg portion 108, making it possible to forge it. Figure 3 shows a self-perforating rivet according to another embodiment of the present disclosure, which forms a polygonal protrusion 301 along the opening of a through hole on the surface of the flange. Even with a shape like the protrusion 301, the protrusion collapses during fastening while the opening shrinks in diameter, thereby holding the fastened piece in place and preventing it from coming out of the opening.

[0025] Figure 4 shows a self-perforating rivet according to yet another embodiment of the present disclosure, which forms one or more partial protrusions 401 along the opening of a through hole on the surface of a flange. Even with a shape like the protrusions 401, the protrusions collapse during fastening while the opening shrinks in diameter, thereby holding the fastened piece in place and preventing it from coming out of the opening.

[0026] [Method for fastening self-perforating rivets] Figures 5 to 10 illustrate a method for fastening a self-punching rivet 100 to a workpiece 500 according to one embodiment of the present disclosure. Figure 5 shows a set configuration of a self-punching rivet 100 mounted on a driving equipment 504 equipped with a punch 505, and a workpiece 500 including an upper plate 501 and a lower plate 502 installed on a die 506 equipped with a recess 508. In one embodiment, the self-punching rivet 100 may be equipped with a locking portion 201. The self-punching rivet 100 according to the present disclosure can be fastened with a punch similar to that used in general self-punching rivets. In another embodiment, the workpiece 500 may include a further number of workpieces between the upper plate 501 and the lower plate 502.

[0027] Figure 6 shows the state in which the punch 505 is in the process of driving the self-punching rivet 100 into the object to be fastened 500. The self-punching rivet 100 first penetrates the upper plate 501 of the object to be fastened 500, creating the fastened object piece 601.

[0028] Figure 7 shows that when the self-perforating rivet 100, driven in by the punch 505, comes into contact with the recess 508 of the die 506, the force on the protrusion 106 increases, causing the protrusion 106 to collapse, and consequently the opening to close and the diameter of the opening to shrink. In addition, the leg portion 108 that comes into contact with the recess 508 deforms to expand in diameter to conform to the shape of the recess 508.

[0029] In one embodiment, the protrusion 106 does not necessarily have to be completely flattened so as to be flush with the surface of the flange portion 102; it is sufficient that the opening is reduced in diameter. In another embodiment, the protrusion 106 can be flattened while completely closing the opening. By configuring the protrusion 106 so that it is completely flattened and the surface of the flange portion 102 is flush, it becomes possible to weld the flange portion 102 to iron or the like after fastening. Furthermore, by configuring it to completely close the opening, the quality of the welding can be improved.

[0030] In Figure 8, the leg portion 108 is further distorted to follow the shape of the recess 508 and wrap around to the underside of the lower plate 502.

[0031] In Figure 9, the flange portion 102 and the distorted leg portion 108 are clamping the object to be fastened 500.

[0032] Figure 10 shows the state after fastening is completed, with the driving equipment 504 and die 506 removed from the state in Figure 9. Due to the reduced diameter of the opening on the surface of the flange portion 102, the fastened piece 601 is held in place by the opening, preventing it from coming out of the self-perforating rivet. If the self-perforating rivet 100 has a locking portion 201, the fastened piece 601 is locked by the locking portion 201 so as not to come out from the leg portion 108 side of the self-perforating rivet 100. In this embodiment, the locking portion 201 is positioned appropriately on the tubular portion 104 to lock the lower plate portion of the fastened piece 601, and if there are three or more fastened pieces, the locking portion 201 is positioned appropriately on the tubular portion 104 to lock the lowest portion of the fastened piece 601.

[0033] As described above, according to the present invention, after fastening, the opening on the surface of the flange portion 102 is reduced in diameter, so that the fastened piece 601 can be held in place by being locked into the opening and not coming out from the flange portion side of the self-perforating rivet. In addition, if a locking portion 201 is present, the fastened piece 601 can be configured not to come out from the leg portion side of the self-perforating rivet, and in combination with the reduction in diameter of the opening, it is possible to hold the fastened piece 601 inside the self-perforating rivet. Furthermore, if the surface of the flange portion 102 is configured to be flattened when the opening on the surface of the flange portion 102 is reduced in diameter after fastening, the flange portion 102 can be welded to iron or the like after fastening. When fastening an object 500 using the self-punching rivet 100 according to the present invention, a standard punch can be used, which is advantageous because it eliminates the need to use a special punch. [Explanation of Symbols]

[0034] 100 Self-Piercing Rivets 102 Flange section 104 Tubular part 106 Convex part 108 Legs 201 Locking part 301 Polygonal protrusions 401 Partial protrusion 500 Object to be fastened 501 Top plate 502 Lower plate 504 Driving equipment 505 Punch 506 Die 508 recess 601 Fragment of fastened object

Claims

1. A self-perforating rivet having a through hole in the axial direction, A flange portion having the opening of the through hole, A tubular portion extending from the flange portion, A leg portion extending from the tubular portion on the side opposite to the flange portion and It has, A protrusion is formed on the surface of the flange portion along the opening, A self-perforating rivet characterized in that, when the object to be fastened is fastened by the self-perforating rivet, the protrusion is crushed while the opening is reduced in diameter.

2. The self-perforating rivet according to claim 1, wherein a locking portion with a reduced inner diameter for locking a piece to be fastened is formed on the inner wall of the tubular portion.

3. The self-perforating rivet according to claim 1 or claim 2, wherein the protrusion forms one or more partial protruding shapes along the opening.

4. A method of fastening objects using a self-perforating rivet having a through hole in the axial direction, The self-perforating rivet described above is A flange portion having the opening of the through hole, A tubular portion extending from the flange portion, A leg portion extending from the tubular portion on the side opposite to the flange portion and It has, A protrusion is formed on the surface of the flange portion along the opening of the through hole, When the self-perforating rivet is driven into the object to be fastened, As the protrusion is crushed and the opening is reduced in diameter, the object to be fastened is held in place so that it does not slip out of the opening. A method wherein the leg portion expands in diameter, causing the flange portion and the leg portion to clamp the object to be fastened.

5. The method according to claim 4, characterized in that when the self-perforating rivet penetrates the object to be fastened, the fastened piece generated from the object to be fastened does not fall out in the direction of the leg portion by a locking portion with a reduced inner diameter formed on the inner wall of the tubular portion.

6. The method according to claim 4 or claim 5, wherein the self-perforating rivet is fastened such that the surface of the flange portion of the fastened rivet becomes flat.

Images