JP3602582B2 - Manufacturing method of electrode for resistance welding - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a resistance welding electrode suitably used for thermal caulking or welding of a metal wire or a metal wire bundle.
[0002]
[Prior art]
Conventionally, as an electrode for this type of resistance welding, a heat-resistant alloy having high electric conductivity and heat conductivity and excellent mechanical strength has been used as an electrode material, and alumina-dispersed Cu, Cu-Re, Cr-Cu There are also known those in which a current-carrying member made of an alloy or the like is brazed, and those in which the electrode tip and the current-carrying member are made of the same material and integrated.
[0003]
Further, Japanese Patent Application Laid-Open No. 4-4984 discloses a resistance welding electrode in which an electrode tip is completely embedded in a current-carrying member in order to strengthen the joint between the electrode tip and the current-carrying member.
[0004]
However, the conditions for the electrode to be welded or to be caulked while the metal wire bundle is pressurized in the mold and energized, and that the electrode for welding should have conditions such that the electrode tip does not fall off the current-carrying member and the electrode tip does not weld to the welding partner side In addition, there is a condition that the electrode tip does not thermally deform. In view of this condition, an electrode of a type in which the electrode tip is completely embedded in the current-carrying member is disadvantageous in that the current-carrying member is usually soft metal and thus is easily thermally deformed as a whole, or the current-carrying member and the welding partner are welded to each other. Tends to occur.
[0005]
As a means for strengthening the joint between the electrode tip and the current-carrying member without completely embedding the electrode tip in the current-carrying member, a tungsten skeleton, which is a contact member, is used as a contact member, and Cu as a current-carrying material is dissolved therein. Japanese Patent Application Laid-Open No. 1-120718 discloses a structure in which the electrodes are immersed and directly joined, and the joining by the infiltration method is applied to the joining between an electrode tip and a current-carrying member in a resistance welding electrode for thermal caulking. However, there is concern about strength as an electrode tip material, and a resistance welding electrode having higher heat resistance and a strengthened joint surface is required.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to have a bonding force such that the electrode tip does not fall off from the current-carrying member even when an external force is applied when applying heat caulking of the metal wire bundle, and furthermore, the electrode tip does not thermally deform, and An object of the present invention is to provide a method of manufacturing an electrode for resistance welding in which a wire bundle and an electrode tip are not welded.
[0007]
[Means for Solving the Problems]
The present invention provides a heat-resistant casting jig container, in which a portion corresponding to the burial depth of an electrode tip in a current-carrying member is inserted into a space from the bottom surface thereof, and is installed in this space area. For resistance welding, a current-carrying member is inserted in an amount to form a current-carrying portion, and the current-carrying member is heated and melted in a non-oxidizing atmosphere to directly join the buried surface of the electrode tip and the fused current-carrying portion. This is a method for manufacturing an electrode.
[0008]
The degree of melting and burial of the electrode tip is the length of the electrode, and the base part with a length of 1/5 or more is buried, which increases the bonding strength and energizing area of the bonding surface. It is preferable from the point of measures.
[0009]
As the electrode tip, a high melting point metal such as W or Mo or a composite thereof can be used. As the current-carrying member, a metal having sufficient electric conductivity and sufficient strength as an electrode material, such as Cu simple metal or Cu-Cr. Materials can be used.
[0010]
According to the present invention, a portion corresponding to the burial depth of the electrode tip in the current-carrying member is placed in a heat-resistant casting jig container such as a graphite or ceramic material having poor wettability with the current-carrying member. The electrode chip is installed in such a way that it enters the space from the bottom surface, and an amount of current-carrying members is formed in this space to form a current-carrying part, and the current-carrying members are heated and melted in a non-oxidizing atmosphere. The electrode for resistance welding is obtained in which the buried surface and the current-carrying portion are firmly adhered and joined .
[0011]
In addition, Ni or Ni-P iron group metal is interposed at least in part of the buried portion of the electrode chip by means of coating or plating, thereby causing a diffusion reaction when the current-carrying member is melted and causing the current-carrying member to be in contact with the current-carrying member. A stronger bonding surface can be formed with the electrode tip.
[0012]
[Action]
In the present invention, when the current-carrying member is inserted into the base of the electrode tip, since the current-carrying member is solidified from the molten state to the heat-shrinkage amount during the cooling from the heating state of the electrode tip, the heat shrinkage after the solidification is large. In addition, even if no solid solution occurs, the electrode member and the current-carrying member are very close to each other, and an attractive force acts between atoms, so that a strong bonding force can be obtained even if solid solution does not occur. . If Ni or the like is present, a strong bonding force can be naturally obtained by the solid solution phenomenon, but an undesired phenomenon such as an increase in electric resistance occurs. Therefore, it is desirable that Ni or the like is small.
[0013]
【Example】
An example in which the present invention is applied to an electrode for heat caulking of a Cu wire bundle will be described.
[0014]
Example 1
FIG. 1 shows the appearance of an electrode 10 for thermal caulking according to the present invention, and FIG. 2 shows its cross-sectional structure. In the figure, a current-carrying part 1 surrounds the entire buried surface of a buried part 22 of an electrode chip 2, and a working part 21 thereof is open from the current-carrying part 1. The current-carrying part 1 is made of cylindrical Cu having a diameter of 20 mm and a height of 20 mm, and the electrode tip 2 is made of W having a thickness of 3 mm, a width of 12 mm, and a length of 22 mm. / 5 are buried in the current-carrying part 1.
[0015]
FIG. 3 shows the manufacturing method. In the drawing, reference numeral 3 denotes a casting jig container made of graphite or ceramics. The casting jig container 3 is an integrated container having a space corresponding to the shape and size of the current-carrying member 1 shown in FIGS. 1 and 2, but may have a split structure. A concave portion 4 is formed at the center of the bottom of the casting jig container 3, the electrode tip 2 made of W is inserted into the concave portion 4, and then the Cu powder or Cu piece 5 is inserted into the space of the casting jig container 3. Is filled, and the entire casting jig container 3 is heated to 1300 ° C. in a nitrogen gas atmosphere to melt the filled Cu and form the conducting part 1 integrated with the W electrode chip 2. When this is removed from the casting jig container 3, the electrode 10 shown in FIGS. 1 and 2 is obtained.
[0016]
FIG. 4 shows a state in which the resistance welding electrode 10 thus obtained is applied to thermal caulking of a Cu wire bundle. As shown in the figure, a Cu wire bundle 7 in which a plurality of wires having a fine wire diameter are bundled and a Cu plate 6 are set, and the electrodes 10 are mechanically pressed from both sides and pressed by heat caulking. Then, an end of the Cu wire bundle and a Cu plate were integrated.
[0017]
For comparison, a wire bundle was thermally caulked under the same conditions using an electrode in which the electrode tip was brazed to the current-carrying member and an electrode having a structure in which the entire electrode tip was embedded in the current-carrying part. In some cases, the brazed portion was peeled off, and the life thereof was reduced by about 20% as compared with the present invention on average. Further, in the all-buried type, since the side surface of the electrode chip is made of Cu material, heat generated softened Cu on the side surface and could not pressurize the Cu wire bundle.
[0018]
Example 2
FIGS. 5 and 6 show the appearance of the electrode 20 in which one of the buried surfaces in the current-carrying part 1 is opened and the buried state of the electrode tip 2 in FIGS. 1 and 2 of the first embodiment. Only one surface of the buried portion 21 is open, and the other three surfaces are buried in the conductive material 1. In the case of this embodiment, compared to the case of the first embodiment, the first embodiment is superior in structural bonding strength. The electrode 20 shown in FIG. 1 has a structure in which the base の of the entire length of the W electrode tip 2 is buried in three current-carrying parts 1 on its three surfaces. Ni-P plating is applied to the buried surface in advance. As a result, a diffusion reaction occurred when the current-carrying member was melted, and the strength of the joint surface 9 could be improved. Using this electrode 20, the same thermal caulking of the Cu wire bundle as in Example 1 yielded the same results as in Example 1.
[0019]
However, the temperature of the duty ratio was higher than that of Example 1. This is because an alloy of Ni-P, Cu and W was formed at the bonding interface, and the electrical resistance at the interface was increased.
[0020]
Of course, in Example 2, an electrode having sufficient performance can be obtained without performing Ni-P plating.
[0021]
【The invention's effect】
The following effects are obtained by the present invention.
[0022]
(1) It is possible to obtain an electrode that is excellent in the bonding state between the electrode tip and the current-carrying material and the current-carrying ability.
[0023]
(2) In particular, it is excellent in thermal caulking of a metal wire bundle, and the caulked portion can be handled as an integral metal and can be applied to thermal caulking that can be handled as a single piece.
[0024]
(3) Compared to the brazed type, the electric resistance of the joint surface is small, and there is no variation, and stable welding can be performed.
[Brief description of the drawings]
FIG. 1 shows the appearance of an electrode according to a first embodiment of the present invention.
FIG. 2 shows a sectional structure of the electrode shown in FIG.
FIG. 3 shows a method for manufacturing an electrode of the present invention.
FIG. 4 shows an application example of the electrode of the present invention.
FIG. 5 shows an appearance of an electrode according to a second embodiment of the present invention.
FIG. 6 shows a cross-sectional structure of the electrode shown in FIG.
[Explanation of symbols]
10, 20 Electrode of the present invention 1 Current-carrying part 2 Electrode tip 3 Casting jig container 4 Recess of casting jig container 5 Fused Cu material 6 Guide 7 Wire bundle

Claims (1)

In a heat-resistant casting jig container, the electrode tip is installed with the part corresponding to the burial depth in the current-carrying member inserted into the space from the bottom surface, and the current-carrying part is formed in this space area A method for manufacturing an electrode for resistance welding, comprising: charging an amount of current-carrying member, and heating and melting the current-carrying member in a non-oxidizing atmosphere to directly join the buried surface of the electrode tip and the molten current-carrying portion. .

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