JP6237360B2 - Metal joining method - Google Patents

Description

  The present invention relates to a metal joining method, and more particularly, to a method for joining light metal alloys having low extensibility such as cast products by driving rivets or caulking.

  As a basic strategy for achieving fuel efficiency improvement by reducing the weight of automobiles, it is possible to replace steel materials with nonferrous light metals such as aluminum alloys and magnesium alloys. At that time, replacing the press-formed product of the steel plate with a pressure casting product of light metal has advantages such as simplification of the process by integral forming in addition to weight reduction. However, it may be difficult to replace all steel materials with light metals, and in such a case, it is necessary to join dissimilar metals such as steel materials and light metals.

  As a method for joining members made of light metal alloys, there are a driving rivet (see Patent Documents 1 and 2) that does not require a pilot hole and caulking joining. In these joining methods, since a member is plastically deformed into a fitting shape at a joining portion, there is a problem that a member to be joined having low extensibility such as a cast product is cracked.

Japanese Patent No. 5055104 JP2013-128964A

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a joining method capable of joining without cracking even a light metal alloy having low extensibility.

In order to solve the above problems, the metal bonding method according to the present invention is:
In the metal joining method of superimposing the first metal on the second metal, placing a driving rivet on the surface of the first metal, and plastically deforming and joining the first and second metals,
In advance, in the second metal at the rivet driving point, a recess corresponding to the driving shape of the rivet and shallower than the final driving amount is formed,
The second metal is placed on a die that defines the final driving amount, and the first metal is stacked on the die. And the first and second metals are plastically deformed to the final driving amount.

The metal bonding method according to the present invention has the effects described below by adopting the above-described steps.
By forming a concave portion shallower than the final rivet driving amount in advance in the second metal, the plastic deformation of the second metal in the process of actually driving the rivet is alleviated, and the metal has low ductility. Can be joined without damage.

  Here, when the second metal is a cast product, the concave portion can be formed at the time of casting, and in that case, the absolute amount of plastic deformation related to joining is reduced. In addition, when the recess is warm-pressed, the apparent amount of plastic deformation in the primary pressing process for forming the shallow recess is reduced, and the absolute amount of plastic deformation related to the joining is reduced. Therefore, in any case, breakage can be avoided and high-strength bonding can be reliably performed.

  In the present invention, it is preferable that the lower center portion of the concave portion is in contact with the die in a state where the second metal is placed on the die, and there is an excess gap around the lower metal portion. In this aspect, when the rivet is driven, the plastic deformation to the outer peripheral portion with the excess gap is induced, so that the deformation in which the tip portion of the rivet is expanded to the outer peripheral side is promoted, and higher strength bonding is performed. Can do.

The metal bonding method according to the present invention includes:
In the metal joining method of stacking the first metal on the second metal, driving a punch into the surface of the first metal, plastically deforming the first and second metals, and caulking and joining,
In advance, a recess corresponding to the punching shape of the punch and shallower than the final driving amount is formed in the second metal at the punching point,
The second metal is placed on a die that defines the final driving amount, and the first metal is overlaid on the concave portion by driving the punch with the first metal overlaid thereon. And the first and second metals are plastically deformed to the final driving amount.

  Thus, also in the caulking joining using the punch, as in the case of using the driving-type rivet, by forming a concave portion shallower than the final punching amount in the second metal in advance. In addition, the plastic deformation of the second metal in the step of actually punching and crimping and joining is alleviated, and even a metal having low extensibility can be joined without being damaged.

It is a typical sectional view showing the metal joining method (driving type rivet joining) concerning a 1st embodiment of the present invention. It is typical sectional drawing which shows the metal joining method (driving type rivet joining) which concerns on 2nd Embodiment of this invention. It is typical sectional drawing which shows the metal joining method (caulking joining) which concerns on 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the term metal plate (upper plate, lower plate) refers to a flat part, flange part, extended piece, etc. of a metal part that is three-dimensionally formed by casting or plastic working in addition to a metal flat plate. , Including partial plate-like parts.

  FIG. 1 shows a first embodiment in which a metal joining method according to the present invention is implemented as a drive-type rivet joint between an upper plate 1 and a lower plate 2, wherein (a) shows before joining and (b) shows after joining. Show. In these drawings, a lower plate 2 is a flange portion (lower flange portion) of a lower part made of a non-ferrous light metal such as an aluminum alloy or a magnesium alloy, and an upper plate 1 is an upper part made of an iron-based metal such as a steel plate. The lower plate 2 has a plate thickness t2 larger than that of the upper plate 1.

  The lower plate 2 is a pressure cast product, and a recess 20 corresponding to the driving shape of the rivet 3 is formed in advance at a joint point of the lower plate 2 to be joined to the upper plate 1. The recess 20 is shallower than the final driving amount of the upper plate 1 (rivet 3) defined by the cavity of the die 4 indicated by reference numerals 40a and 40b in FIG. 1A, and the bottom surface 21 of the recess 20 is a cavity. 40 is in contact with (or close to) the bottom surface central portion 40b, but there is an excess gap between the peripheral side surface 22 and the bottom surface peripheral portion 40a. Moreover, the center 20c of the recessed part 20 bulges with respect to a peripheral part, and thickness t3 of the part is larger than plate | board thickness t2.

  The rivet 3 has a foot portion 3b having a slightly small cylindrical shape protruding below the disc-shaped head portion 3a. When the rivet 3 is driven by punching or the like from the upper side of the upper plate 1 toward the recess 20 as shown in FIG. 1 (b), the upper plate 1 is first punched by the foot 3b of the rivet 3, and the lower plate 2 and pressed into the inner cavity 3c of the foot 3b as shown by the arrow c, the tip (lower end) of the foot 3b is expanded as shown by the arrow b, By biting into the inner wall of the recess 20 of the lower plate 2, the rivet 3 is fixed to the lower plate 2 and the upper plate 1 is joined to the lower plate 2.

  At this time, the excessive space (40a) of the die 4 induces plastic deformation of the peripheral portion 23 as indicated by the arrow a, thereby promoting the expansion of the foot portion 3b of the rivet 3 and high strength bonding. Is obtained. Further, since the recess 20 is provided, the plastic deformation of the lower plate 2 due to the driving of the rivet 3 can be reduced, and damage such as cracking due to large deformation can be prevented. Furthermore, the center 20c in which the concave portion 20 bulges promotes the press-fitting of the upper plate punched portion into the inner cavity 3c as shown by the arrow c and the accompanying expansion of the foot portion 3b, thereby contributing to high strength bonding. .

  Next, FIG. 2 shows a second embodiment in which the metal joining method according to the present invention is implemented as a drive-type rivet joint between the upper plate 1 and the lower plate 2, and FIGS. (C) and (d) show a rivet driving process. In the second embodiment, as shown in FIGS. 2A and 2B, the lower plate 2 is set on the die 4, and the concave portion 20 is formed by the punch 5 having the annular bulging portion 51 around the central concave portion 52. Is press-molded.

  The die 4 can be used in common with the rivet driving process shown in FIGS. 2C and 2D, and an excess gap is formed between the peripheral side surface 22 and the bottom surface peripheral portion 40 a at the time of forming the recess 20. As is apparent from the figure, since the tip of the punch 5 has a relatively gentle curved shape, the press forming of the recess 20 is also performed on the lower plate 2 made of a metal having low extensibility by warm forming. Is possible. As described in the first embodiment, high strength bonding can be performed by overlapping the upper plate 1 on the lower plate 2 having such a recess 20 and driving the rivet 3 thereon.

  In addition, when joining together using an adhesive, the adhesive is poured into the concave portion 20 of the lower plate 2, and then the upper plate 1 is stacked and the rivet 3 is driven, whereby a certain amount of adhesive is applied to the rivet 3. The upper plate 1 and the lower plate 2 can be evenly diffused to the joint surface. In this case, even if the bonding surface has an inclination or the lower plate 2 is inclined in the bonding process, the adhesive injected into the recess 20 is difficult to flow. Application and bonding can be performed reliably.

  Next, FIG. 3 shows a third embodiment in which the metal joining method according to the present invention is implemented as caulking joining of the upper plate 1 and the lower plate 2, wherein (a) is before joining and (b) is joining. Shows the back. Also in the case of caulking, as in the case of rivet joining, the concave portion 120 shallower than the final driving amount is formed in the lower plate 12 in advance, and the peripheral surface 122 of the concave portion 120 is set with the lower plate 12 set on the die 8. In this state, an excess gap is formed between the upper plate 11 and the bottom surface peripheral portion 80a, and the punch 7 is driven from the upper plate 11 side toward the concave portion 120, and the house plate 11 and the lower plate 12 are plastically deformed and caulked. A recess 113 is formed, an interlock is formed on the side wall portion of the caulking recess 113, and the upper plate 11 and the lower plate 12 are caulked and joined.

  Also in the case of this caulking joining, since the concave portion 120 of the lower plate 12 is formed in advance by casting, warm forming or the like, the plastic deformation due to the punch 7 driving at the caulking joining is alleviated and the spreadability is low. Even metal can be joined without being damaged. This embodiment is also advantageous when an adhesive is injected into the recess 120 in the same manner as described above, diffused to the joint surface by punching at the time of joining, and caulked and joined together with adhesion.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention. To do.

1,11 Upper plate (first metal)
2,12 Lower plate (second metal)
3 Rivet 4, 8 Die 5, 6, 7 Punch 20, 120 Recess 21 Bottom 22, 23, 122

Claims (6)

In the metal joining method of superimposing the first metal on the second metal, placing a driving rivet on the surface of the first metal, and plastically deforming and joining the first and second metals,
In advance, in the second metal at the rivet driving point, a recess corresponding to the driving shape of the rivet and shallower than the final driving amount is formed,
The second metal is placed on a die that defines the final driving amount, and the first metal is stacked on the die. And the first and second metals are plastically deformed to the final driving amount.   The metal joining method according to claim 1, wherein the second metal is a nonferrous light metal casting.   The metal bonding method according to claim 2, wherein the recess is formed when the second metal is cast. The metal joining method according to claim 1, wherein the concave portion is press-worked or warm press- molded into the second metal.   The lower center portion of the concave portion is in contact with the die in a state where the second metal having the concave portion is placed on the die, and there is an excess gap therearound. Item 5. The metal bonding method according to any one of Items 1 to 4. In the metal joining method of stacking the first metal on the second metal, driving a punch into the surface of the first metal, plastically deforming the first and second metals, and caulking and joining,
In advance, a recess corresponding to the punching shape of the punch and shallower than the final driving amount is formed in the second metal at the punching point,
The second metal is placed on a die that defines the final driving amount, and the first metal is overlaid on the concave portion by driving the punch with the first metal overlaid thereon. And the first and second metals are plastically deformed to the final driving amount.

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