JPH06226465A - Spot welding electrode - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an electrode for spot welding capable of improving the number of continuous dots. [Configuration] electrode 1 ₁ is more composed a rod-like electrode member 2, a heat dissipation layer 3 provided on the outer peripheral surface of the electrode body 2.
The heat dissipation layer 3 is made of diamond, has a higher thermal conductivity than the electrode body 2, and has excellent electric insulation. The heat dissipation layer 3 prevents the electrode body 2 from accumulating heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode for spot welding, and more particularly to an electrode suitable for spot welding Al plates or Al alloy plates to each other.

[0002]

2. Description of the Related Art Electrodes of this kind are required to have high thermal conductivity, high electrical conductivity and high hardness, and therefore Cu alloys have been mainly used as the electrode material. (See JP-A-63-264280).

[0003]

However, when the member to be welded is an Al plate or an Al alloy plate, it has a high thermal conductivity and a high electric conductivity, so that it has a high current and a short time. However, the heat dissipation of the Cu alloy electrode cannot follow that condition, and as a result, Cu and Al react with the heat accumulation of the electrode to alloy the electrode surface with the pickup. However, there was a problem in that the number of consecutive dots was low.

In view of the above, it is an object of the present invention to provide the electrode for spot welding, which has a good heat dissipation property and can improve the number of continuous welding points.

[0005]

In the spot welding electrode according to the present invention, a heat dissipation layer having a higher thermal conductivity than that of the electrode body and excellent electrical insulation is provided on the outer peripheral surface of the rod-shaped electrode body. It is characterized by that.

The spot welding electrode according to the present invention is
A heat dissipation promoting layer having a thermal conductivity at least equal to that of the electrode body is provided on an outer peripheral surface of the heat dissipation layer.

[0007]

With the heat dissipation layer, the generated heat can be efficiently dissipated without leaking the current flowing through the electrode body, and the heat storage of the electrode body can be avoided, whereby the number of continuous dots can be improved. It will be possible.

If a heat dissipation promoting layer is provided on the outer peripheral surface of the heat dissipation layer, the heat dissipation of the electrode body can be further improved.

[0009]

EXAMPLES Referring to FIGS. 1 and 2, a spot welding electrode 1
Reference numeral ₁ comprises a rod-shaped electrode body 2 and a heat dissipation layer 3 provided on the outer peripheral surface thereof. The electrode body 2 has a high conductivity with an electric conductivity IACS of 80% or more, and a material with a high thermal conductivity,
For example, it is made of oxygen-free copper (hereinafter referred to as OFCu). The heat dissipation layer 3 is made of a material having higher thermal conductivity than the electrode body 2 and excellent electrical insulation, for example, diamond. Here, an electrically insulating material has an electrical resistance of 10
^It means that it is ¹² μΩcm or more.

Table 1 compares various characteristics of OFCu and diamond.

[0011]

[Table 1]

[0012] In the electrode 1 ₁ of the two-layer structure, by its heat dissipation layer 3, without leakage current flowing through the electrode body 2, the heat generated by efficiently dissipated to avoid heat accumulation in the electrode body 2 it is possible, it becomes possible to improve the number of consecutive RBI electrodes 1 _1.

[0013] is hit in the manufacture of the electrode ₁ 1, OFCu
For example, a rod-shaped electrode body 2 having an outer diameter of 16 mm on the tip side is manufactured by machining, and then the outer peripheral surface of the electrode body 2 is made of diamond by a combustion flame method or a plasma CVD method, for example, a thickness of 10 μm. The method of forming the above-mentioned heat dissipation layer 3 is adopted.

[0014] Figure 3, the electrode 1 ₂ shows a modification in which the three-layer structure, the outer peripheral surface of the heat dissipation layer 3, which was provided with a heat radiation promoting layer 4 having at least the electrode member 2 and the thermal conductivity equivalent is there. In this modified example, the heat dissipation promotion layer 4 is O
It is composed of FCu. The electrode 1 ₂ thinner consisting OFCu the outer peripheral surface of the heat dissipation layer 3 is obtained by fitting example cylindrical body having a thickness of about 3mm burnt.

When the heat dissipation promoting layer 4 is provided on the outer peripheral surface of the heat dissipation layer 3 in this manner, the heat dissipation of the electrode body 2 is further improved, and the number of continuous dots of the electrode 1 ₂ is increased as compared with the case where only the heat dissipation layer 3 is used. It can be further improved. The heat dissipation promotion layer 4 is not energized.

FIG. 4 shows the relationship between various electrodes and the number of continuous dots until picking up when an Al alloy plate is spot-welded. Welding conditions are current 21000
A, pressure 430kgf, pressurization time 8 cycles, Al
Material of alloy plate A5182 material, thickness of Al alloy plate 1.
It is 2 mm.

As is apparent from FIG. 4, the number of continuous dots of the two-layer structure electrode 1 ₁ having the thickness of the heat dissipation layer 3 of about 25 μm is Cu.
-The number of consecutive dots of the three-layer structure electrode 1 ₂ is twice that of the Cr alloy electrode, the thickness of the heat dissipation layer 3 is about 20 μm, and the thickness of the heat dissipation promotion layer 4 is about 3 mm. it is to increase the 1.9 times that of the structure electrodes 1 _1.

[0018]

According to the present invention, the number of continuous welding points in spot welding can be significantly improved by forming the electrode in the two-layer structure or the three-layer structure as described above.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a spot welding electrode.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view showing a modified example of the electrode for spot welding,
It corresponds to FIG.

FIG. 4 is a graph showing the relationship between various electrodes and the number of continuous dots.

[Explanation of symbols]

1 ₁ , 1 ₂ electrode 2 electrode body 3 heat dissipation layer 4 heat dissipation promotion layer

Claims (4)

[Claims] 1. A rod-shaped electrode body (2) is provided with a heat dissipation layer (3) having a higher thermal conductivity than that of the electrode body (2) and an excellent electrical insulation property on the outer peripheral surface thereof. Spot welding electrode. 2. The electrode for spot welding according to claim 1, wherein a heat dissipation promoting layer (4) having a thermal conductivity at least equal to that of the electrode body is provided on an outer peripheral surface of the heat dissipation layer (3). 3. The spot welding electrode according to claim 1, wherein the heat dissipation layer (3) is made of diamond. 4. The spot welding electrode according to claim 2, wherein the electrode body (2) is made of oxygen-free copper, and the heat dissipation promoting layer (4) is made of the same material as the electrode body (2). .