JPH0357342Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention relates to the improvement of aluminum alloy welding guns.
The purpose is to increase cooling efficiency, reduce contact resistance changes due to electrode potential differences between dissimilar metals, and improve resistance.

(Prior art) In aluminum alloy welding guns used to reduce the weight of welding guns, the entire welding gun becomes hot due to the electrode tip and arm heat generated during operation, as with other welding guns. , continuous use was impossible.

Therefore, conventionally, as described in Japanese Patent Publication No. 45-2449, a copper tube was cast inside an aluminum alloy gun arm, and cooling water was passed through the copper tube to cool the gun arm and electrode chip. I've come to think of it.

(Issues to be solved by the invention) However, in the case of the above-mentioned conventional technology, impurities such as moisture and oil adhering to the surface of the copper tube become gaseous when exposed to heat of around 900℃ during the casting process. It evaporates, and the copper tube itself oxidizes at high temperatures, resulting in nest-like roughness between the arm base material and the copper tube, which impairs the adhesion between the gun arm and the copper tube, significantly reducing the cooling function. In many cases, when a large welding current is applied or when the welding is operated at full capacity, abnormal overheating occurs and workability is significantly impaired, and furthermore, the electrical potential difference between aluminum and copper alloy impedes resistance to corrosion. However, there were problems such as not being able to withstand actual use and having weak mechanical strength.

Therefore, an attempt was made to use an aluminum alloy cooling pipe of the same quality as the aluminum alloy gun arm, but in that case, the aluminum with the highest ionization tendency corroded in the cooling system passage, and as a result, the corroded part leached out. This caused a situation in which the continuous operation of the welding gun became impossible because the flow of cooling water was obstructed.

Therefore, the inventors of the present invention attempted various measures to further improve the above-mentioned disadvantages.

For example, replacing an aluminum cooling pipe with a copper or copper alloy pipe of the same type as the electrode chip,
We also attempted to improve cooling efficiency and reduce manufacturing costs by welding this to the side of the aluminum alloy gun arm.

However, welding a part of the cooling pipe of an aluminum alloy gun with copper or copper alloy may cause contact corrosion due to dissimilar metals between the aluminum and copper or copper alloy, or may cause improper welding of the copper alloy and aluminum. Because there is no standard welding method, they encountered difficult problems such as the mating parts peeling off due to the heat during welding.

(Means for Solving the Problems) Therefore, the present invention solves the various problems mentioned above, increases cooling efficiency, reduces contact resistance change due to electrode potential difference between dissimilar metals, improves resistance to corrosion, and further improves cooling efficiency. This is intended to reduce costs. Specifically, in a welding gun in which a cooling water pipe is arranged on the side of an aluminum alloy gun arm, the cooling water pipe is a copper or copper alloy pipe whose outer peripheral surface is made of aluminum. This invention relates to an aluminum alloy welding gun that is coated with an alloy pipe and joined to the side surface of a gun arm.

(Function) The cooling water pipe that is joined to the side of the gun arm made of aluminum alloy is a copper or copper alloy pipe whose outer circumferential surface is covered with an aluminum alloy pipe of the same quality as the gun arm. Aluminum alloy pipes can be easily joined by argon arc welding instead of copper alloy pipes, and since the cooling water does not come into contact with the aluminum, there is no corrosion, and there is no risk of the cooling water flow being obstructed by the elution of corroded parts. It disappears.

(Example) The specific content of the present invention will be explained below based on the example shown in the drawings. In the figure, 1 is a welding gun, 3 is an aluminum alloy gun arm having an electrode tip 4a at its tip, and 5 is a piston rod having an electrode tip 4b at its tip. It is constructed so that it can be brought into contact with and separated from the electrode chip 4a via the object W to be welded.

A cooling pipe extending from a cooling water branch pipe 6 is disposed along the side surface of the aluminum alloy welding gun arm 3, and the tip of the cooling pipe reaches the electrode tip 4a.

Further, as the cooling pipe, as shown in cross section in FIG. 2, a pipe 8 made of copper or copper alloy is used for the cooling water passage.

Furthermore, the outer peripheral surface of the copper or copper alloy pipe 8 described above is covered with an aluminum alloy pipe 2 of the same quality as the gun arm described above.

Covering with the aluminum alloy pipe 2 is performed by inserting a copper or copper alloy pipe whose outer diameter is approximately equal to the inner diameter of the aluminum alloy pipe on the inner peripheral side of the aluminum alloy pipe in the axial direction from the side opening of the aluminum alloy pipe. This is done by press-fitting it into the

Next, this is bent to match the shape of the gun arm 3, and then joined to the side surface of the gun arm 3 by means such as argon arc welding.

In addition, although the above explanation was about the C type welding gun,
Needless to say, similar applications can be obtained for type welding guns and others.

(Effects of the invention) As described above, the cooling water pipe is installed on the side of the aluminum alloy gun arm, so compared to the conventional case where a copper pipe is cast inside the arm. Good workability and high mechanical strength. In addition, the above cooling water pipe has a copper or copper alloy pipe whose outer circumferential surface is covered with an aluminum alloy pipe, so it has good heat conduction efficiency, and in particular, the bonding performance is significantly higher than when directly joining a copper or copper alloy pipe to the gun arm. This is good, and the cooling effect of the gun arm can be further improved.

In addition, since the cooling water does not come into contact with the aluminum parts, there is no corrosion problem caused by inhibition of corrosion resistance due to the potential difference between the aluminum and copper alloy, and there is no problem of corrosion caused by the elution of the corroded parts, unlike when using conventional aluminum pipes. There is no risk of water flow obstruction within the pipe.

Furthermore, the manufacturing process of the welding gun can be simplified and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention. FIG. 2 shows a sectional view taken along the line AA in FIG. 1, respectively. 2... Aluminum alloy pipe, 3... Gun arm,
8...Pipe made of copper or copper alloy.

Claims (1)

[Scope of utility model registration request] In a welding gun in which a cooling water pipe is installed on the side of an aluminum alloy gun arm, the cooling water pipe is a copper or copper alloy pipe whose outer peripheral surface is covered with an aluminum alloy pipe, and the aluminum alloy pipe is installed on the side of the gun arm. Aluminum alloy welding gun made by joining.