JPH07299570A - Resistance welding method of copper member - Google Patents

Abstract

PURPOSE:To strongly join copper members each other by executing resistance welding while sandwiching a specific alloy between joining parts of copper members. CONSTITUTION:In a first opening part 16 of an electrode 12, a copper member 20a of material to be welded is inserted while directing its width direction in vertical direction and its length direction in horizontal direction, in a second opening part 18 of a electrode 12, a copper member 20b of material to be welded is inserted while aligning its thickness direction with the copper member 20a and directing in vertical direction. Successively, between copper members 20a, 20b, a heat generating material 22 of AgZnSn alloy is sandwiched, it is subjected to joining by welding. After the first energizing cycle, a cooling cycle of four cycles is provided, further, after completing the cooling cycle, a second welding current smaller than the first welding current is energized. By this method, toughness of the joined part is improved. life quality for a copper bus bar is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance welding method for a copper member, wherein an AgZnSn alloy which is a heat generating member is interposed between joint portions of copper members which are welding members to perform resistance welding.

[0002]

2. Description of the Related Art Copper is widely used as a material for electric and electronic parts because of its excellent electrical conductivity and thermal conductivity. Among these electrical and electronic parts, especially when manufacturing copper busbars (busbars), they can be integrally molded by bending or other processing, tightened between copper members with bolts, or between copper members. A brazing method and the like for joining the materials with a molten brazing material are generally used.

However, in the method of integral molding,
As the processing cost rises, the yield of the copper material decreases due to the plastic flow direction of the copper member itself, and the material cost becomes expensive. In addition, the method of tightening the bolt has a problem that the tightening work is complicated and is easily affected by a disturbance such as vibration. Furthermore, the brazing method has a disadvantage that the bonding strength is inferior to that of the other methods.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 57-115983, an insert material of a metal plate having a larger specific resistance than the metal material to be welded is provided between the contact surfaces of the metal materials to be welded. A resistance welding method is known which is characterized by sandwiching and then heating and pressure welding (hereinafter referred to as Conventional Example 1). In addition, JP-A-61-25833
As disclosed in Japanese Unexamined Patent Publication (Kokai), a butt welding method is known, in which a metal material is butt-welded and then intermittently energized for tempering (hereinafter referred to as Conventional Example 2). That).

[0005]

However, in the above-mentioned conventional example 1, since the insert material is sandwiched between the contact surfaces of the metal materials to be welded, the metal materials to be welded are heated and pressure welded to each other. It has been pointed out that when a copper member is used as the metal material to be welded, the bending strength decreases after welding, and it cannot be used as a copper bus bar in the area affected by disturbances such as yield reduction and vibration during production. . Further, in the above-mentioned conventional example 2, although the toughness of the welded portion is improved, it has been pointed out that the desired tensile strength required for the copper bus bar cannot be secured.

The present invention is intended to solve this type of problem, and the resistance welding of a copper member which can effectively maintain the quality as a copper bus bar and can easily reduce the manufacturing cost. The purpose is to provide a method.

[0007]

In order to achieve the above-mentioned object, the present invention provides AgZnS between the joining parts of copper members.
After the n-alloy is interposed, a first welding current is applied in a state in which a predetermined pressure is applied to the copper members, and a second welding current smaller than the first welding current is applied after a predetermined period of rest. Is characterized by.

[0008]

In the resistance welding method for copper members according to the present invention, the AgZnSn alloy is interposed between the joining portions of the copper members to perform resistance welding, thereby firmly joining the copper members. it can. Further, the second welding current smaller than the first welding current is applied to the copper members heat-bonded by the application of the first welding current, so that the copper member has desired tensile strength and toughness. Therefore, it is preferably used as a method for manufacturing a copper bus bar.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The resistance welding method for copper members according to the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 indicates a resistance welding machine according to a first embodiment for carrying out the resistance welding method of the present invention, and electrodes 12 and 14 of this resistance welding machine 10 face each other. And is relatively movable forward and backward. A first opening 16 is formed in the lower electrode 12 by cutting out in the diametrical direction, and a second rectangular opening 18 elongated in the axial direction is formed in the upper electrode 14. .

Therefore, the copper member 20a, which is the material to be welded, is inserted into the first opening 16 of the electrode 12 with the width direction oriented vertically and the length direction oriented horizontally, while the electrode 14 is inserted. To the second opening 18 of the copper member 20 that is the material to be welded
b is inserted so that its thickness direction is aligned with the copper member 20a and is oriented in the vertical direction. Therefore, the copper members 20a, 20b
Has the advantage that it is accurately positioned and firmly held on the electrodes 12 and 14, respectively, and that the welding and joining work described below can be performed with high accuracy and efficiency.

Next, AgZ is applied between the copper members 20a and 20b.
After the heat generating material 22, which is an nSn alloy foil, is interposed (see FIG. 2).
), The copper members 20a and 20b are butted and welded to each other.

As concrete conditions, copper members 20a, 20
The width W of b is 15 mm and the thickness t is 3 mm, and the heat generating material 2
The thickness of 2 is 0.2 mm. The first welding current is 25-
At 30 kA, the first energization cycle is set to 15 to 20 cycles and the pressing force is set to 250 to 300 kgf. The first welding current and the first energization cycle were set under the setting condition based on the experimental result that the strength higher than the bolt fastening, that is, the tensile strength of 400 kgf or more and the durability strength of 3.5 G × 10 ⁷ or more were obtained. Yes, and its details are shown in FIG. Although FIG. 3 shows the experimental results of the butt welding joining together with the butt welding joining, the explanation of the butt welding joining will be described later.

Further, a cooling cycle of 4 cycles is provided subsequent to the first energization cycle, and after the completion of this cooling cycle, a second welding current of 10 to 15 kA is energized in a second energization cycle of 5 to 10 cycles. (See the timing chart of FIG. 4 and Table 1).

[0015]

[Table 1]

Next, the effect obtained by passing a second welding current between the copper members 20a and 20b after the heating and joining by the first passage cycle as in the present embodiment, that is, the tempering effect, was tested by the following experiment. An example will be described.

First, as shown in FIG. 5, butt-welding is performed using the expanded copper bus bars (copper members) 30a and 30b, and a joint 32 is provided between the copper bus bars 30a and 30b. It was Copper bus bar 30a, 30b
Uses a bus bar of JIS standard size, and the size is shown in Table 2.

[0018]

[Table 2]

Therefore, assuming that the width of the joint portion 32 is 1 mm, the correlation between each cross-sectional area and the resistance value of the JIS standard size bus bar in Table 2 is shown in the curve A of FIG. On the other hand, considering the relationship with welding current, each JI
The range of current applied to the S standard size bus bar is shown in FIG.
Is indicated by a broken line curve B in FIG.

Therefore, the curve B was used as the basic condition for the first welding current, and the joining strength was compared with that obtained by adding the second welding current thereto. The specific conditions are the copper bus bar 30.
The thickness W of a and 30b is 3.0 mm, the first welding current is 25
kA, the first energization cycle is 15 cycles, the cooling cycle is 4 cycles, the second welding current is 10 kA and the second
The energization cycle was 5 cycles, the applied pressure was 250 kgf, and the thickness of the heat generating material 22 was 0.2 mm. (Comparison of Tensile Shear Strength) A test piece welded only in the first energization cycle and a test piece in which a cooling cycle and a second energization cycle were carried out after the first energization cycle (tempered energization) were prepared. The strength of each of the welded copper bus bars 30a, 30b was measured by a tensile tester in a direction away from each other. The result is shown in FIG. As a result, there is almost no difference in the bonding strength between the case where the welding is performed only by the first energization cycle and the case where the welding is performed by adding the second energization cycle to the welding. The result was that the strength was stable in a certain range. (Comparison of Bending Strength) The joint portions 32 of the copper bus bars 30a and 30b welded as shown in FIG. 5 are joined to each other by using a jig bar (not shown).
A load is applied until it reaches 0 °, at which time the joint 32
It was confirmed whether or not a crack had occurred in the. The load when bent at 90 ° was 380 kgf (3724N).

As a result, in the test piece welded only by the first energization cycle, cracking occurred in 12 out of 30 samples and the pass rate was 60%, while the second energization cycle was performed. In addition, in the welded test piece, none of the 30 samples had cracks, and the pass rate was 10
It was 0%.

As a result, the toughness of the joint portion 32 is improved all at once by applying the second energization cycle, and it is possible to reliably withstand external disturbances such as vibrations, thereby improving the durability quality of the copper bus bar. Was obtained. Moreover, it is not necessary to consider the plastic flow direction of the copper material itself, the copper material can be used with high yield, and the manufacturing cost of the copper bus bar can be kept low. (Comparison of hardness) As shown in FIG. 8, the copper bus bar 30a,
30b was cut in the longitudinal direction and the hardness of each point P1 to P6 was measured. The results are shown in Table 3.

[0023]

[Table 3]

From these results, it is considered that the copper bus bars 30a and 30b are softened by the application of the second energization cycle, which causes a decrease in hardness and an improvement in bending strength.

By the way, in the first embodiment, the copper member 20 is used.
The case of butt welding joining of a and 20b has been described, but the present invention is not limited to this, and the same applies to butt welding joining shown in FIG. The electrodes 40 and 42 used for this butt welding are arranged so as to face each other and be relatively movable back and forth.
2, the first and second openings 44 and 46 are formed.

The copper member 4 is provided in the first opening 44 of the electrode 40.
8a is inserted with the thickness direction oriented vertically and the length direction oriented horizontally, while the copper member 48b extends in the width direction of the copper member 48a in the second opening 46 of the electrode 42. It is inserted in alignment with the vertical direction and in the vertical direction. Next, after the heat generating material 50, which is a foil of AgZnSn alloy, is interposed between the copper members 48a and 48b, the copper members 48a and 4 are
8b is butted and welded.

The specific conditions for this butt-welding joint are shown in Table 1, FIG. 3 and FIG. 10. Although there are some numerical differences from the above-mentioned butt-welding joint, the conditions are substantially the same. It is set. Therefore, in the butt welding, the same effect as that of the butt welding can be obtained.

[0028]

According to the resistance welding method for a copper member of the present invention, the following effects and advantages can be obtained.

The copper members can be firmly joined to each other by interposing an AgZnSn alloy between the joining parts of the copper members and performing resistance welding. Further, the copper members heat-bonded by the application of the first welding current to each other, the first
By supplying the second welding current smaller than the welding current, the copper member can have desired toughness while maintaining desired tensile strength. Therefore, it is possible to effectively secure various durability qualities required for the copper bus bar and easily reduce the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a resistance welding machine according to a first embodiment for carrying out a resistance welding method for a copper member according to the present invention.

FIG. 2 is an explanatory view showing a state in which a copper member and a heat generating material are arranged between electrodes that constitute the resistance welding machine.

FIG. 3 is a relationship diagram for setting conditions of an energization cycle and a current value.

FIG. 4 is a timing chart of butt welding joining.

FIG. 5 is a perspective view of a copper bus bar used in a comparative test.

FIG. 6 is a relationship diagram of a cross-sectional area, a resistance value, and a welding current.

FIG. 7 is a relationship diagram of tensile shear strength.

FIG. 8 is an explanatory diagram of a copper bus bar used in a hardness comparison test.

FIG. 9 is an explanatory diagram of butt welding joining.

FIG. 10 is a timing chart of butt welding joining.

[Explanation of symbols]

10 ... Resistance welding machine 12, 14 ... Electrodes 16, 18 ... Openings 20a, 20b
... Copper member 22 ... Exothermic material 30a, 30b
... copper bus bar 32 ... joint portions 40,42 ... electrodes 44,46 ... openings 48a, 48b
… Copper member 50… Exothermic material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seimei Iwabuchi 1-10-1 Shin-Sayama, Sayama-shi, Saitama Honda Engineering Co., Ltd.

Claims (2)

[Claims] 1. An AgZnSn alloy is interposed between the joining parts of copper members, a first welding current is passed under a condition that a predetermined pressure is applied to the copper members, and the first welding current is passed for a predetermined time. A resistance welding method for a copper member, characterized in that a second welding current smaller than one welding current is passed. 2. The method of claim 1, wherein the AgZ
A resistance welding method for a copper member, wherein the copper member having an nSn alloy interposed therein is subjected to a resistance welding operation in a state of being fitted into an opening formed in an electrode.