JPH0768387A - Spot welding electrode - Google Patents

Abstract

PURPOSE:To obtain the electrode without leakage of cooling water at the time of exchanging a tip by fixing a recessed part of the cap-shaped tip attachably and detachably on the projecting part outside of the shank tip and provided a defective conductor base member on the tip surface of the projecting part. CONSTITUTION:Although the base end side of a hollow bar-shaped shank 20 is opened, a copper projecting part member is fitted watertightly and, then, welded to the tip side to form the projecting part 22. The copper cap-shaped tip 30 is fixed on the projecting part 22 and the electrode is constituted. At least one pore 31 to communicate the noncontact part outside 33 of materials to be welded of the cap-shaped tip 30 with the vicinity of the recessed part 32 base for press fitting and sticking is provided. In addition, the defective conductor base member 34 is provided on the tip surface of the projecting part 22. Consequently, since a water path in a hollow part 24 of the shank 20 is not communicated with the air at the time of exchanging the cap-shaped tip 30, the water leakage is not caused.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to spot welding electrodes.

[0002]

2. Description of the Related Art An electrode for spot welding is composed of a shank 51 having a through hole 52 in the direction of the central axis for a cooling water channel and a tip 53 fitted and fixed to the tip thereof, as shown in FIG.

Since the chip 53 is a consumable item, it must be frequently replaced with a new one. When exchanging the tip 53, the water channel was blocked, but water leakage could not be avoided.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrode rod for spot welding in which water leakage does not occur at the time of tip replacement.

[0005]

A means for solving the problems will be described with reference to FIGS. In the spot welding electrode according to the present invention, a convex portion 22 is provided at the tip of the shank 20, the cap-shaped tip 30 is detachably fixed to the outer side of the convex portion 22, and a bottom member made of a defective conductor is attached to the tip surface of the convex portion 22. 34 is provided.

[0006]

When the tip is replaced, the water channel is not opened, so that no water leakage occurs. Further, when the cap-shaped tip 30 falls off, the bottom surface member 34 made of the defective conductor hits the object to be welded and does not conduct electricity, so that the fall of the tip 30 can be immediately known.

[0007]

EXAMPLE A hollow rod-shaped shank 20 is open at the base end side thereof, but a copper convex member is liquid-tightly fitted on the distal end side thereof and then welded 25 to form a convex portion 22. The copper cap-shaped tip 30 is fixed to the convex portion 22 to form the electrode rod 10. At least one fine hole 31 is provided to connect the outer surface 33 of the non-contacted part of the hat-shaped tip 30 and the vicinity of the bottom surface of the press-fitting contact recess 32. Further, a bottom member 34 made of a defective conductor is provided on the tip surface of the convex portion 22.

When the shank 20 is attached to a holder (not shown), the water pipe 41 extending from the holder is attached to the shank 20.
It passes through the inside and reaches the vicinity of the inner surface in the convex portion 22. When the concave portion of the cap-shaped tip 30 is removably fixed to the convex portion 22, a loose taper 21 is provided on the convex portion 22 so that the cap-shaped tip 30 may be press-fitted and closely attached. The inner screw of the cap-shaped tip 30 may be screwed onto the outer screw of 22.

If the recessed portion of the cap-shaped tip 30 is detachably fixed by interposing the lubricant 23 on the outer side of the convex portion 22, the detachment is facilitated.

The lubricant 23 is preferably an electrically conductive lubricant such as a mixture of carbon and grease, but even with grease alone, the thin grease layer is partially cut off in the press-fitted state, and the convex portion 22 is formed.
The cap-shaped chip 30 and the cap-shaped chip 30 are in close contact with each other, and the electrical conductivity is maintained.

A fixing means other than welding may be used when the member with a copper convex portion is fitted in the hollow rod-shaped shank 20 in a liquid-tight manner and then fixed.

[0012]

When the cap-shaped tip 30 is replaced, the water passage in the hollow portion 24 of the shank 20 does not communicate with the outside air, so that water leakage does not occur. Further, when the tip 30 falls off, the bottom member 34 made of a poor conductor hits the object to be welded and does not conduct electricity. Therefore, the tip 30 is immediately noticed and the tip of the convex portion does not cause erroneous welding to damage the convex portion. .

Even when the present invention is applied to a shank with a non-water channel, it is useful for reducing the cost of the tip and facilitating the tip replacement.

[Brief description of drawings]

FIG. 1 is a vertical cut front view of a spot welding electrode according to the present invention.

FIG. 2 is an exploded view of FIG.

FIG. 3 is a sectional view taken along line AA of FIG.

FIG. 4 is a vertical cut front view of a spot welding electrode in a conventional example.

[Explanation of symbols]

 10 Electrode Rod 20 Shank 21 Tapered Part 22 Convex Part 23 Lubricant 24 Hollow Part 25 Welding 30 Cap Shaped Tip 31 Pore 32 Recess 33 Outer Surface 34 Bad Bottom Member 41 Water Tube 42 Pore 51 Shank 52 Through Hole 53 Chip

Claims (1)

[Claims] 1. A shank (20) is provided with a convex portion (22) at the tip thereof, and the concave portion of the cap-shaped tip (30) is detachably fixed to the outside of the convex portion (22) and the tip of the convex portion (22). An electrode for spot welding, which has a bottom member (34) made of a defective conductor on its surface.