JPS6329629B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a gun arm made of aluminum or an aluminum-based alloy (hereinafter referred to as an aluminum-based material), and an electrode tip holder made of copper or a copper alloy material that supports an electrode tip. This relates to a spot welding gun with a structure that combines
More specifically, the present invention relates to a spot welding gun in which the gun arm is configured to prevent electrical contact occurring at the mechanical contact surface between aluminum-based materials at the joint between the electrode tip and the holder.

Needless to say, it is desirable that this type of welding gun be lightweight so that it can be driven and operated freely by workers and industrial robots.

Therefore, recently, in order to reduce the weight of welding guns,
The trend is for gun arms to be made of lightweight, highly conductive aluminum-based materials instead of traditional heavy copper or copper alloy materials.

On the other hand, the electrode tip and holder of a welding gun must have sufficient electrical properties and mechanical strength to handle both of these requirements, as they must be able to carry a large current under the enormous pressure of a pressurizing cylinder. Furthermore, due to the need to facilitate machining, maintenance, etc., copper or copper alloys are used as materials that meet these requirements.

Therefore, when an aluminum-based material is used for the gun arm, the electrode chip holder and the gun arm are assembled so that they can be separated between different metals.

Conventionally, when assembling a gun arm and an electrode chip holder as described above, they are bolted together either directly or by inserting a thin copper plate, copper wire mesh, etc. between them. Aluminum-based materials have extremely strong oxidizing properties and form an oxide film on the contact surface, resulting in high contact resistance.

Since a large welding current flows through this contact surface, contact resistance occurs on the contact surface, further promoting oxidation. Furthermore, since a strong pressure is repeatedly applied to this portion, the contact pressure fluctuates and surface oxidation is accelerated. In this way, the connection surfaces are severely damaged and so-called electrolytic corrosion occurs, leading to a drop in the welding current and, in extreme cases, no current flow.
As described above, when aluminum-based materials are used for conductive parts, there is a major drawback in that electrolytic corrosion on the connection surfaces not only reduces welding quality but also significantly reduces the durability and functionality of the welding gun. Ta.

In order to solve the above-mentioned conventional drawbacks, the present invention provides a structure in which the gun arm is made of aluminum-based material and the joint part with the electrode tip holder has great durability and stability. It is something.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an example of a C-shaped welding gun, and FIG. 3 shows an example of an X-shaped welding gun.

In the figure, 1 indicates a gun arm made of aluminum-based material. 2 is an electrode connection piece, which is made of the same material 2a as the gun arm, as shown in FIG.
The copper plates 3 are integrated by explosion welding to form a laminated plate.

The electrode connection piece 2 and gun arm 1 are
The connection is made by welding means W such as TIGMIG welding and friction welding.

4 is a pressure cylinder fixed to the other side of the gun arm, 5 is a piston rod 6 of this pressure cylinder.
shows an electrode tip that is moved by a pressurized cylinder. Reference numeral 7 denotes an electrode tip holder, and bolts B are inserted into the bolt holes 11 made in the electrode connection piece 2 of the gun arm and the bolt holes 11 made in the engaging body 7a of the electrode tip holder 7, and the copper plate 3 is removed. It is tightly tightened to the surface of the

8 is an electrode tip detachably attached to the tip of the electrode head tip holder; 9 is a cable 1 connected between a welding transformer (not shown) and gun arm 1;
This is a conductor connection terminal connected at 0.

As described above, according to the present invention, a gun arm made of aluminum-based material is used to reduce the weight of the spot welding gun, and the mechanical joint with the electrode tip holder is provided with a contact surface made of aluminum-based material. Since the electrode tip and holder do not have any This is particularly effective for large spot welding guns, where weight reduction is an issue, as the function can be significantly stabilized.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of a C-type spot welding gun according to the present invention, FIG. 2 is an explanatory diagram showing an example of an electrode connection piece in the present invention, and FIG.
FIG. 7 is an explanatory diagram showing another embodiment of the spot welding gun according to the present invention. Explanation of symbols: 1... Gun arm, 2... Electrode connection piece, 3... Copper plate, 7... Electrode chip holder, 8... Electrode chip.

Claims (1)

[Claims] 1. An electrode connecting piece 2 made of aluminum or an aluminum alloy made by explosion welding a copper plate 3 is welded to the end of the gun arm 1 made of aluminum or an aluminum alloy material on the side of the electrode chip polder 7, and this and copper or a copper alloy are welded together. A spot welding gun to which an electrode tip holder 7 consisting of is combined.