JP5279531B2 - Method for caulking and joining metal plates - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of joining metal plates by caulking, which has high joining strength and also the intra-plane anisotropy of strength reduced as much as possible. <P>SOLUTION: A plurality of metal plates are placed in piles on movable blades which are installed by being divided into three pieces on the outer periphery of a three-pronged fork type fixed anvil; a top metal plate is plastically deformed by pushing the three-pronged fork type columnar punch in the metal plate from the upper part; and also a bottom metal plate is plastically deformed by setting the movable blades which are arranged dividedly on the outer periphery of the fixed anvil free respectively in the outer peripheral direction and individually and the upper and lower metal plates are joined mechanically. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for caulking and bonding metal plates, and more particularly, to a method for caulking and bonding metal plates having high bonding strength and no in-plane strength anisotropy.

As a method for fixing and joining a plurality of stacked metal plates, a method using a fastener represented by a bolt or a rivet is generally used. However, the method using the fastener is not only costly, but the head of the fastener protrudes from the surface of the metal plate, which may impair aesthetics in handling or appearance. For this reason, welding methods such as spot welding and caulking joining may be employed.
In the spot welding method, there are cases where it is difficult to join materials with different plate thicknesses or different types of materials, and there is a case where post-repair is required for the plated material because of the thermal effect on the material. In addition, the spot welding method involves scattering and fume at the time of joining, and thus there is a risk of deteriorating the working environment.

Since caulking can be joined during press working, the equipment synchronism and working environment are good. For this reason, caulking is frequently used in fields such as automobiles, home appliances, and houses.
However, the caulking joining method has a problem that the joining strength is lower than a method using a fastener or a spot welding method. For example, when joining using a caulking device equipped with a round punch or die, there is a disadvantage that it is weak against the force in the rotational direction along the planar portion of the member to be joined.

In addition, when a crimping device equipped with a square punch or die is used for joining, a sheared surface is generated in the crimped part, so that the direction of the shear strength at the joined part is generated. Although it is high, the shear strength in the parallel direction is not so high, and the joint portion is sheared, so that there is a problem that the cut end of the material exists and the air tightness and water tightness are lowered.
In order to solve such a problem, for example, Patent Document 1 proposes that the shearing surfaces of the structural members sheared by the punch and the die are caulked so as to have a substantially cross shape orthogonal to each other.

JP 2001-321856 A

According to Patent Document 1, it is possible to obtain a joining member that has little directionality in the shear strength of the joining portion and that is strong against force in the rotational direction.
However, even Patent Document 1 fails to sufficiently reduce the in-plane anisotropy of strength. Therefore, in order to eliminate the in-plane anisotropy of strength, in some cases, it is necessary to perform a plurality of caulking joints in different directions, which causes a cost increase.
The present invention has been devised to solve such problems, and provides a method for caulking and joining metal plates having high joining strength and reducing in-plane anisotropy of strength as much as possible. With the goal.

  In order to achieve the object of the caulking and joining method of the metal plate of the present invention, a plurality of metal plates are stacked and placed on the movable blade arranged in three parts on the outer periphery of the three-pronged fixed anvil, from above. A metal plate on the lower surface is formed by locally pushing a three-pronged columnar punch into the metal plate, plastically deforming the upper metal plate, and individually disengaging the movable blades arranged separately on the outer periphery of the fixed anvil in the outer peripheral direction. The upper and lower metal plates are mechanically joined by plastic deformation.

According to the method of the present invention, a caulking joint extending in three directions is formed by using a three-pronged columnar punch and a movable blade moving in three directions. As a result, the in-plane anisotropy of the bonding strength can be reduced as much as possible.
In addition, by forming the crimp joint extending in three directions, the length of the side wall portion becomes relatively long, so that the joint strength is greatly improved, and a joint having high joint strength can be obtained by a simple joining method. It will be.

Conceptual diagram explaining the caulking method Diagram explaining the difference in joint strength between the caulking and spot welding methods The figure which shows the shape of the punch used for the method of this invention, an anvil, and a movable blade The figure explaining the direction change aspect of the crimping joining in an Example The figure which shows the relationship between the direction rotation angle at the time of caulking joining, and side wall part length The figure which shows the relationship between the direction rotation angle and the joint strength at the time of caulking The figure which shows the relation between the direction rotation angle at the time of caulking and the bonding strength punch area ratio

  FIG. 1 shows a general caulking joining method. After the two metal plates 1 and 2 are stacked on the blade 6, the metal plates 1 and 2 are sandwiched between the blade 6 by the stripper 4, fixed and set, and then the metal plate 1 set by the cylindrical punch 3. , 2 are plastically deformed so as to project the material radially outward from the anvil 5, and the metal plates 1 and 2 are joined. When caulking and joining are performed using a caulking device equipped with a normal round punch or die, the length of the side wall portion of the caulked joint is approximately the circumference of the punch. When the joint strength is compared between the case where the joint thickness is 1.6 mm and the joint strength is the same when spot welding is performed so that the dimensions of the joint are the same, the joint strength of the crimp joint is 2 Generally, it is about 30% (see FIG. 2). In addition, there is a problem that it is weak against the force in the rotational direction along the planar portion of the members to be joined.

As described above, the caulking joining method is a simple method, but also has a relatively low joining strength, and thus is one factor that the usage frequency does not increase.
And as introduced in the above-mentioned Patent Document 1, the in-plane anisotropy of the bonding strength is sufficient even with the method in which the caulking joint is made into a substantially cross shape using a four-fork punch and a movable blade moving in four directions. It cannot be resolved.

Therefore, the present invention uses a three-pronged punch and a movable blade that moves in three directions so that the caulking joint is substantially Y-shaped.
Details will be described below.
First, FIG. 3 shows a schematic shape of a tridental columnar punch to be used and a movable blade arranged in three parts on the outer periphery of the tridental fixed anvil. If such a punch and a movable blade are installed in a press apparatus as shown in FIG. 1 used in the conventional caulking joining method, the method of the present invention can be carried out.

That is, after the metal plates 1 and 2 to be joined are placed on the movable blade arranged in three parts on the outer periphery of the three-pronged fixed anvil, the three-pronged columnar punch is locally applied to the metal plate from above. The metal plates 1 and 2 are plastically deformed so as to fill the gap formed on the fixed anvil.
After the metal plates 1 and 2 are plastically deformed so as to fill the gap formed on the fixed anvil, the metal plate material itself moves outward and presses and moves the movable blade in the outward direction. The bottomed concave portion along the cross-sectional shape is formed to join the metal plates 1 and 2 together. After that, the columnar punch 3 is pulled out and the caulking is finished.

As the two metal plates to be joined, a steel plate having a mechanical thickness shown in Table 1 having a thickness of 1.6 mm was used as a base plate, and plated steel plates with Zn-Al-Mg alloy plating on both surfaces were used. .
(1) Example of use of a four-forked punch Four-forked punch with a piece length of 3 mm, a width of 4 mm, and a taper angle of 120 degrees, a piece of length of 8 mm, a width of 4.3 mm, and a height of 4 mm, and A square prism blade having a length of 8 mm, a width of 8 mm, and a height of 5.1 mm was used.
On the movable blade arranged on the outer periphery of the anvil having such a shape, positioning was performed in a state where two bonded plated steel plates were stacked. Subsequently, the two plated steel sheets were sandwiched between the blades by a stripper and fixed. The punches having the shape described above were pushed into the two plated steel sheets from above with a load of 100 kN, and the two plated steel sheets were caulked and joined.

(2) Usage example of a tridental punch A piece of 3 mm length, a width of 4 mm, a taper angle of 120 degrees, a piece of tridental punch, a piece length of 8 mm, a width of 4.3 mm, a height of 4 mm, and a length of 10 mm A pentagonal prism blade having a width of 8 mm and a height of 5.1 mm was used.
Two plated steel sheets were caulked and joined in exactly the same manner as when using the above-mentioned four-forked punch.
The two types of caulking joining were performed on the plated steel plates fixed by being tilted at various predetermined angles in the direction of the arc arrow with the vertical arrow direction being 0 ° as shown in FIG.

The two types of joined bodies that are caulked and joined at various predetermined angles, that is, those in which a four-forked punch is pushed in and those in which a three-forked punch is pushed in, are arranged in the manner shown in FIG. The length of the part was measured. The result is shown in FIG.
Moreover, the tensile test was done about the said 2 types of joined body. In the tensile test, the shear tensile strength was measured according to JIS Z 3137. The result is shown in FIG.
Furthermore, the relationship between the rotation angle and the punch area ratio of the bonding strength obtained by dividing the bonding strength by the area of the bottom of the three-forked punch and the four-forked punch shown in FIG. 4 was also investigated. The result is shown in FIG.

As is clear from the results shown in FIGS. 5 and 6, when the trident punch is used as compared with the case where the four fork punch is used, the change in the length of the side wall is not affected by the change in the caulking direction. The in-plane anisotropy of the bonding strength is extremely small.
Further, from the results shown in FIG. 7, it is understood that the punch area ratio of the bonding strength is larger when the trident punch is used. That is, when a three-pronged punch is used during caulking, a desired joint strength can be obtained by forming a relatively small caulking joint.

Claims (1)

  A plurality of metal plates are placed on a movable blade arranged in three parts on the outer periphery of a three-pronged fixed anvil, and a three-pronged columnar punch is locally pushed into the metal plate from above, and the upper metal plate The upper and lower metal plates are mechanically joined by plastically deforming the lower metal plates by individually escaping the movable blades separately arranged on the outer circumference of the fixed anvil in the outer circumferential direction. A method for caulking and bonding metal plates.

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