JP2014121710A - Rivet and rivet joint structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rivet which reduces a protruding amount of a head part and enables easy riveting, and to provide a rivet joint structure.SOLUTION: A rivet 1 is used for connecting a first member 2 with a second member 3 formed by a metal different from the first member 2. The rivet 1 is formed by a material that may weld the first member 2 and has hardness larger than that of the second member 3. The rivet 1 includes: a shaft part 12 that is inserted into and disposed at a prepared hole 31 which is formed at the second member 3 penetrating therethrough, and is welded to the first member 2; and a head part 11 which is disposed at one end of the shaft part 12 and sandwiches the second member 3 with the first member 2. The shaft part 12 includes: a tip part 13 which is smaller than an inner diameter of the prepared hole 31; a base end part 15 which is larger than the inner diameter of the prepared hole 31; and a diameter reduction part 14 which is formed between the base end part 15 and the tip part 13 so as to reduce its diameter.

Description

  The present invention relates to a rivet and a rivet joining structure used for connecting a first member and a first member and a second member made of a different metal.

  Conventionally, the body of an automobile is mainly formed of a steel material such as a high-tensile steel plate. Further, in order to reduce the weight, a part of the vehicle body, for example, a roof panel or a hood panel may be formed of a light alloy such as an aluminum alloy. In such a case, it is necessary to join dissimilar metal materials of a frame made of a steel material and a panel made of a light alloy.

  As a structure for joining dissimilar metal materials, for example, there is a structure in which a steel material and a light alloy material disclosed in Patent Document 1 are joined using rivets. The rivet is made of an iron-based material, and has a substantially cylindrical shaft portion and a disk-shaped head portion disposed at one end of the shaft portion. The shaft portion has a proximal end portion adjacent to the head portion and a distal end portion that is disposed on the side opposite to the proximal end portion side and has an outer diameter larger than the outer diameter of the proximal end portion. In addition, an annular groove portion is formed on the back surface of the head portion so as to be along the boundary between the shaft portion and the base end portion.

The rivet of Patent Document 1 uses a shaft portion as a punch to form a through hole in a light alloy material. Further, with the shaft portion inserted through the through hole, a rivet and a light alloy material are sandwiched between the upper die and the lower die, and the rivet is caulked and fixed to the light alloy material. At this time, the material portion around the through hole in the light alloy material is caused to flow into the inside of the concave groove portion of the head by being pressed by the convex portion of the lower mold.
Then, the steel material and the light alloy material are connected via the rivet by spot welding the rivet and the steel material fixed by caulking to the light alloy material.

JP 2009-285678 A

However, the joint structure of Patent Document 1 has the following problems.
In the above connection structure, the inner diameter of the through hole formed in the light alloy material by the shaft portion of the rivet corresponds to the outer diameter of the distal end portion in the shaft portion, and therefore compared with the outer diameter of the proximal end portion in the shaft portion. Big. When the rivet is caulked and fixed, it is necessary to flow the material portion of the light alloy material into the base end portion of the shaft portion and the groove portion of the shaft portion using a lower mold having a convex portion. Therefore, the structure of the lower mold for performing caulking and fixing of rivets becomes complicated and cannot be caulked and fixed easily.

  Further, since the through hole is formed in the light alloy material by using the shaft portion of the rivet as a punch, the rivet head needs to have a strength that can withstand the applied pressure. Furthermore, since the recessed groove part is formed in the back surface of the head in a rivet, the thickness becomes large in order to ensure the strength of the head. For this reason, the head part protrudes greatly from the surface of the light alloy material.

  The present invention has been made in view of such a background, and an object of the present invention is to provide a rivet and a rivet connection structure that can be easily caulked and fixed while reducing the protrusion amount of the head.

One aspect of the present invention is a rivet used to connect a first member and a second member made of a metal different from the first member,
It is made of a material that can be welded to the first member and has a hardness higher than that of the second member.
A shaft portion that is inserted through a pilot hole that is formed through the second member and is welded to the first member, and is disposed at one end of the shaft portion, and the second member is disposed between the first member and the first member. With a sandwiched head,
The shaft portion has a distal end portion smaller than the inner diameter of the pilot hole, a proximal end portion larger than the inner diameter of the pilot hole, and a diameter smaller than the distal end portion between the proximal end portion and the distal end portion. The rivet is characterized in that it has a reduced diameter portion formed by the above method (claim 1).

According to another aspect of the present invention, the first member and the second member are connected by caulking and fixing the rivet to the second member and welding the shaft portion of the rivet and the first member. A rivet joint structure,
The edge portion of the pilot hole in the second member is crushed by the base end portion of the material portion facing the base end portion, and the portion facing the reduced diameter portion swells to closely contact the shaft portion. It is in the rivet joining structure characterized by the above-mentioned (Claim 4).

In the rivet and the rivet joint structure, the shaft portion of the rivet has the distal end portion, the proximal end portion, and the reduced diameter portion, whereby the following excellent operational effects can be obtained.
That is, the material portion of the second member pressed by the base end portion is crushed by inserting and arranging the shaft portion of the rivet into the pilot hole and pressurizing the rivet in the axial direction. And when this material part is crushed, the surplus thickness generated in the second member flows into a space formed between the reduced diameter portion and the inner peripheral surface of the pilot hole. Thereby, the material portion of the second member facing the reduced diameter portion swells toward the shaft portion, and the rivet can be caulked and fixed to the prepared hole. Thus, the fluidity of the surplus can be improved by making the pressing direction of the rivet and the flow direction of the surplus in the second member the same direction. Therefore, the rivet can be easily caulked and fixed to the second member.

  Further, the rivet shaft portion is caulked and fixed in the prepared hole formed in advance in the second member without using the rivet as a punch. Moreover, it is not necessary to form a concave groove part in the back surface of the said head in the said rivet. Therefore, in order to ensure the strength of the head in the rivet, it is not necessary to increase the protruding amount, and the protruding amount of the head can be reduced.

  Moreover, the hardness of the rivet is set larger than the hardness of the second member. Therefore, deformation of the rivet can be prevented, and the second member can be easily and reliably deformed.

  As described above, according to the rivet and the rivet connection structure, it is possible to reduce the amount of protrusion of the head and to easily fix it by caulking.

The side view which shows the rivet in Example 1. FIG. FIG. 3 is a lower plan view showing a rivet in the first embodiment. The elements on larger scale of FIG. Sectional drawing which shows the rivet fixed by crimping to the 2nd member in Example 1. FIG. The elements on larger scale of FIG. Sectional drawing which shows the rivet joining structure in Example 1. FIG.

  In the rivet, the shaft portion may be formed such that an outer diameter from the distal end portion to the base end portion via the reduced diameter portion is changed into a curved surface shape. In this case, the surplus flow in the second member can be smoothly performed. In addition, the material portion of the second member pressed by the base end portion and the material portion that swells in opposition to the reduced diameter portion can be easily adhered to the outer peripheral surface of the shaft portion. Therefore, the rivet can be more firmly caulked and fixed to the second member.

  In addition, the shaft portion has a volume that is smaller than the virtual shaft portion and a diameter that is larger than the virtual shaft portion, with respect to a virtual shaft portion that is vertically formed with the same outer diameter as the tip portion. It may be formed so that the volume of the portion is substantially the same (claim 3). In this case, the deformation amount in the material portion facing the base end portion and the deformation amount in the material portion facing the reduced diameter portion can be made substantially the same. Thereby, while the surplus movement in the said 2nd member can be performed smoothly, the said material part facing the said reduced diameter part can be firmly stuck to the outer peripheral surface of the said axial part. Therefore, the rivet and the second member can be caulked and fixed more firmly.

Example 1
An embodiment relating to a rivet and a rivet connection structure will be described with reference to FIGS.
As shown in FIG. 6, the rivet 1 is used to connect the first member 2 and the second member 3 made of a different metal from the first member 2.

As shown in FIGS. 1 and 5, the rivet 1 is made of a material that can be welded to the first member 2 and has a hardness higher than that of the second member 3. The rivet 1 is inserted and disposed in a pilot hole 31 formed through the second member 3, and is disposed at one end of the shaft portion 12 to be welded to the first member 2 and the first member 2 ( 6) and a head 11 that sandwiches the second member 3 therebetween.
The shaft portion 12 has a distal end portion 13 smaller than the inner diameter of the pilot hole 31, a proximal end portion 15 larger than the inner diameter of the pilot hole 31, and a contraction between the proximal end portion 15 and the distal end portion 13 than the distal end portion 13. And a reduced diameter portion 14 formed to have a diameter.

This will be described in more detail below.
As shown in FIG. 6, in this example, spot welding is performed to join the rivet 1 to the first member 2, and the first member 2 made of a steel material and the second member 3 made of a light alloy material, The rivet joint structure 100 to be connected is related.
The first member 2 is made of an SS material that is an iron-based material and has a flat plate shape.

  As shown in FIGS. 4 and 5, the second member 3 is made of an aluminum alloy flat plate and has a through hole 31 formed therethrough. The pilot hole 31 has a circular shape, and its inner diameter is set to be slightly larger than the outer diameter of the distal end portion 13 in the shaft portion 12 and smaller than the maximum outer diameter of the proximal end portion 15.

  As shown in FIGS. 1 and 4, the rivet 1 that is caulked and fixed to the pilot hole 31 of the second member 3 is made of an SS material that is an iron-based material, and includes a shaft portion 12 that is inserted into the pilot hole 31 and a shaft. And a head portion 11 disposed at one end of the portion 12.

As shown in FIGS. 1 and 2, the head 11 has a substantially disk shape, and the entire outer peripheral edge of the upper surface thereof is chamfered. In this example, the thickness t (axial dimension) of the head 11 is 0.4 mm. The thickness t of the head 11 preferably has a relationship of t ≦ 0.5 mm. In this case, the protrusion amount of the head 11 can be reduced while ensuring the strength of the head 11. Further, a sealing material may be applied to prevent moisture or the like from flowing between the first member 2 and the second member 3 or between the rivet 1 and the second member. At this time, if the protruding amount of the head 11 is small, the sealing material is disposed so as to cover the head 11, so that the sealing can be surely performed.
Even when the thickness t is out of the above range, the above-described effect can be obtained, but it is more effective to make it within the above range.

  As shown in FIGS. 1 and 2, the shaft portion 12 has a substantially cylindrical shape, a distal end portion 13 smaller than the inner diameter of the prepared hole 31, a proximal end portion 15 larger than the inner diameter of the prepared hole 31, and a proximal end Between the portion 15 and the tip portion 13, there is a reduced diameter portion 14 formed with a diameter smaller than that of the tip portion 13. The shaft portion 12 has an outer diameter from the distal end portion 13 through the reduced diameter portion 14 to the proximal end portion 15 formed in a smooth curved surface shape. The axial length L between the end portion of the distal end portion 13 and the end portion of the proximal end portion 15 in the shaft portion 12 is substantially the same as the plate thickness t2 of the second member 3.

  As shown in FIGS. 1 and 2, a substantially conical protrusion 16 that protrudes toward the tip end in the axial direction is formed on the end face of the tip end portion 13. Thereby, the current of spot welding can be concentrated on the projection part 16, and the rivet 1 and the 1st member 2 can be joined easily and reliably.

  As shown in FIG. 3, the shaft portion 12 has a volume V <b> 1 of a portion smaller in diameter than the virtual shaft portion 120 with respect to the virtual shaft portion 120 formed perpendicularly with the same outer diameter as the tip portion 13, and the virtual shaft portion. It is formed so that the volume V2 of the portion whose diameter is larger than 120 is substantially the same.

As shown in FIGS. 4 and 5, the rivet 1 formed as described above is caulked and fixed to the second member 3.
First, the shaft portion 12 of the rivet 1 is inserted into the prepared hole 31. At this time, the base end portion 15 of the rivet 1 comes into contact with the edge portion of the prepared hole 31. As shown in FIG. 5, the rivet 1 is further moved to the distal end side in the axial direction while being pressurized, so that the material portion P <b> 1 facing the proximal end portion 15 is crushed by the proximal end portion 15. At the same time, in the second member 3, the surplus generated by crushing the material portion P <b> 1 moves to a portion facing the reduced diameter portion 14, and the material portion P <b> 2 on the inner peripheral surface of the prepared hole 31 is moved to the shaft portion 12. Inflate to the side. As a result, the inner periphery of the pilot hole 31 is in close contact with the shaft portion 12, and the rivet 1 and the second member 3 can be caulked and fixed.

  As shown in FIG. 6, the first member 2 is arranged on the distal end side of the rivet 1 with respect to the second member 3 to which the rivet 1 is caulked and fixed. In this state, electrodes (not shown) are arranged on the head 11 of the rivet 1 and the back side of the first member 2 facing the tip 13 of the rivet 1. Then, by energizing each electrode while applying pressure, a nugget 121 in which the contact portion between the rivet 1 and the first member 2 is melted and solidified is formed, and the rivet 1 and the first member 2 are spot-welded. Thereby, the 2nd member 3 is clamped between the head 11 of the rivet 1 and the 1st member 2, and the 1st member 2 and the 2nd member 3 are joined.

  Thus, the fluidity | liquidity of surplus can be improved by making the pressurization direction of the rivet 1 and the flow direction of surplus in the 2nd member 3 into the same direction. Therefore, the rivet 1 can be easily caulked and fixed to the second member 3.

  Further, the hardness of the rivet 1 is set larger than the hardness of the second member 3. Therefore, deformation of the rivet 1 can be prevented, and the second member 3 can be easily and reliably deformed.

  Further, the shaft portion 12 of the rivet 1 is caulked and fixed to the prepared hole 31 formed in advance in the second member 3 without using the rivet 1 as a punch. Further, it is not necessary to form a concave groove on the back surface of the head 11 in the rivet 1. Therefore, in order to ensure the strength of the head 11 in the rivet 1, it is not necessary to increase the protruding amount, and the protruding amount of the head 11 can be reduced.

  Further, the shaft portion 12 is formed such that the outer diameter from the distal end portion 13 to the proximal end portion 15 via the reduced diameter portion 14 is changed into a curved surface shape. For this reason, it is possible to smoothly flow surplus in the second member 3. Further, the material portion P1 of the second member 3 pressed by the base end portion 15 and the material portion P2 that swells facing the reduced diameter portion 14 can be easily brought into close contact with the outer peripheral surface of the shaft portion 12. Therefore, the rivet 1 can be caulked and fixed to the second member 3 more firmly.

  In addition, the shaft portion 12 has a volume V1 that is smaller than the virtual shaft portion 120 and larger than the virtual shaft portion 120 with respect to the virtual shaft portion 120 that is formed perpendicularly with the same outer diameter as the tip portion 13. It is formed so that the volume V2 of the diameter portion is substantially the same. Therefore, the deformation amount in the material portion P1 facing the base end portion 15 and the deformation amount in the material portion P2 facing the reduced diameter portion 14 can be made substantially the same. Accordingly, the surplus movement of the second member 3 can be smoothly performed, and the material portion P2 facing the reduced diameter portion 14 can be securely adhered to the outer peripheral surface of the shaft portion 12. Therefore, the rivet 1 and the second member 3 can be caulked and fixed more firmly.

  As described above, according to the rivet 1 and the rivet joining structure 100 of the present example, it is possible to reduce the amount of protrusion of the head 11 and easily perform caulking and fixing.

  In this example, the rivet 1 and the first member 2 are made of the same material. However, the present invention is not limited to this, and the rivet 1 and the first member 2 are made of different materials as long as they can be welded together. There may be.

DESCRIPTION OF SYMBOLS 1 Rivet 100 Rivet joining structure 11 Head 12 Shaft part 13 Tip part 14 Reduced diameter part 15 Base end part 16 Projection part 120 Virtual shaft part 2 1st member 3 2nd member 31 Pilot hole

Claims (4)

The first member and the first member are rivets used to connect the second member made of a dissimilar metal,
It is made of a material that can be welded to the first member and has a hardness higher than that of the second member.
The shaft member is inserted and arranged in a pilot hole formed through the second member, and is welded to the first member. The shaft member is disposed at one end of the shaft portion, and the second member is interposed between the first member and the shaft member. With a sandwiched head,
The shaft portion has a distal end portion smaller than the inner diameter of the pilot hole, a proximal end portion larger than the inner diameter of the pilot hole, and a diameter smaller than the distal end portion between the proximal end portion and the distal end portion. And a rivet characterized by having a reduced diameter portion formed.   The rivet according to claim 1, wherein the shaft portion is formed such that an outer diameter from the distal end portion to the base end portion via the reduced diameter portion is changed to a curved surface shape. Rivet to do.   The rivet according to claim 1 or 2, wherein the shaft portion has a volume of a portion whose diameter is smaller than that of the virtual shaft portion with respect to a virtual shaft portion formed perpendicularly with the same outer diameter as the tip portion. A rivet characterized in that it is formed so that the volume of the portion whose diameter is larger than that of the imaginary shaft is substantially the same. The rivet according to any one of claims 1 to 3 is caulked and fixed to the second member, and the shaft portion of the rivet and the first member are welded, whereby the first member and the second member are welded. A rivet joint structure for connecting members,
The edge portion of the pilot hole in the second member is crushed by the base end portion of the material portion facing the base end portion, and the portion facing the reduced diameter portion swells to closely contact the shaft portion. A rivet joint structure characterized by that.

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