JPH0523866A - Forming method for spot welding tip - Google Patents

Abstract

PURPOSE:To simplify the forming process of a spot welding tip having a use limit display part on the outside surface, and to curtail a tip material. CONSTITUTION:A forging die is constituted of the lower die 1 and the upper die 2. On the inside surface of the lower die 1, a projecting line 4 for forming a use limit display part 11 of a tip 10 is formed in the axial direction. At the same time an external shape of the tip 10 is forged by a forging die, the use limit display part 11 is formed on the outside surface of the tip 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a spot welding tip attached to the tip of an electrode for spot welding.

[0002]

2. Description of the Related Art Spot welding is a method of energizing a work such as a sheet metal object and an electrode and welding the work in a spot shape by heat generated by its electric resistance. A spot welding tip is provided at the tip of the electrode. (Hereinafter, abbreviated as a chip.)
Is installed. FIG. 5 shows this chip 50, which is entirely molded of copper-chromium alloy or the like, and has a jacket 51 for cooling water which is formed in a hollow shape in the axial direction on the side where it is attached to the electrodes. Further, a peripheral groove is formed on the tip side thereof as the usage limit display portion 52 of the chip 50. The usage limit display section 52 displays a wear limit based on repeated use of the chip. That is, if spot welding is repeated, the tip of the tip 50 gradually collapses,
It is necessary to correct the shape with a grinding tool such as a file, and the tip end is worn out due to this shape correction. As this wear progresses, the tip of the tip approaches the jacket 51 side,
On the other hand, the cooling property of the tip of the tip is improved, but on the other hand, the nugget melted in the spot shape during spot welding is excessively cooled and the melting is insufficient, so that the quality of welding is deteriorated. The usage limit display section 52 clearly indicates such a limit of wear of the tip 50, and when the tip of the tip reaches the display section 52, it is suggested to replace the tip. Therefore, when molding the chip 50, it is necessary to form the usage limit indicator 52.

6 to 8 show a conventional method of molding such a chip 50. The tip 50 is formed by forging, and as shown in FIG.
And a forging die consisting of the upper die 62 is used. Lower mold 61
Is for molding the outer shape of the chip, and a chip material 63 such as a copper-chromium alloy is filled inside. Upper mold 6
Reference numeral 2 is for molding the jacket 51, and a projecting portion 64 for molding the jacket is integrally provided vertically. In such a forging die, the tip 50 is formed by pressing the tip material in the lower die 61 and the upper die 62. FIG. 7 shows a molded chip 50, which has a contour and a jacket 51.
And are integrally formed. FIG. 8 shows a process of forming the usage limit display portion 52 on the chip 50. While rotating the chip 50, the cutting tool 65 is cut to form a circumferential groove as the usage limit display portion 52 on the outer surface of the chip 50. is doing.

[0004]

In the conventional chip forming method, since the chip is forged and the usage limit indicator is engraved, the number of processes is large and the productivity is poor. Further, since the usage limit display portion is formed by cutting, the chip material becomes chips and scatters, and the material is wasted.

The present invention has been made in consideration of such conventional problems, and an object of the present invention is to provide a method of molding a chip which has good productivity and is free from waste of material.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is a forging die comprising a combination of an upper die and a lower die, which is formed on the inner surface of the lower die corresponding to a usage limit indicating portion of a spot welding tip. And forming the portion, and using the forging die, the use limit indicating portion is integrally formed on the outer surface of the spot welding tip when the spot welding tip is forged.

[0007]

In the above construction, since the outer shape of the chip and the usage limit indicator are simultaneously formed at the time of forging, the number of processes is reduced and it is not necessary to perform cutting, resulting in waste of material. Disappear.

[0008]

The present invention will be described in more detail below. In the present invention, the outer shape of the chip and the use limit surface portion of the outer surface of the chip are simultaneously formed by forging. FIG. 1 shows a forging die used for this forging, which includes a lower die 1 and an upper die 2. The lower mold 1 is for molding the outer shape of the chip 10, and a recess 3 corresponding to the outer shape of the chip is formed in the axial direction. On the inner surface of the concave portion 3, a plurality of protrusions 4 are formed as molding portions for molding the usage limit display portion 11 of the chip 10. In this embodiment, the usage limit indicator 11 has a groove shape extending in the axial direction of the chip 10 as shown in FIGS. 2 and 3, and by forming a plurality of grooves on the outer surface of the chip 10, Envelope 1 connecting the tip of the groove
2 indicates the limit of wear. Therefore, a plurality of protrusions 4 are formed in the axial direction on the inner surface of the lower mold 1 so as to correspond to the grooves. On the other hand, the upper mold 2 is a jacket 1 for water cooling.
3 (see FIGS. 2 and 3) is formed on the chip 10, and a projection 5 for this purpose is vertically provided integrally.

In such a forging die, a chip material such as a copper chromium alloy is inserted into the recess 3 of the lower die 1 and the upper die 2
The tip material is pressed by abutting on the lower mold 1. By this pressurization, the outer shape of the chip 10 and the hollowed-out jacket 13 are forged. At the time of this forging, a groove serving as a usage limit indicator 11 is simultaneously formed on the outer surface of the chip 10. Therefore, the step of forming the usage limit display portion 11 by cutting is unnecessary, the productivity is improved, and the material loss due to cutting is also eliminated.

FIG. 2 and FIG. 3 show a chip 10 molded as described above, on the outer surface of which a usage limit indicator 1 is provided.
A plurality of grooves as 1 are formed in the axial direction. Spot welding is performed using this tip 10, and the tip 10 is exchanged when the tip 10 reaches the usage limit display portion 11 as shown by the broken line in FIG.

The present invention is not limited to the above embodiment, but various modifications can be made. For example, the usage limit display section 1
1 may be a ridge, and in this case, a groove corresponding to the ridge is formed on the inner surface of the lower mold as a molding portion. Further, the usage limit display portion may be formed in the radial direction on the outer surface of the chip.

[0012]

Industrial Applicability According to the present invention, since a chip is molded by using a forging die having a molding portion corresponding to the usage limit display portion on the inner surface, a cutting process for forming the usage limit display portion is not required, and the production is performed. Properties are improved and material loss is reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a forging die used in an embodiment of the present invention.

FIG. 2 is a side view of a chip molded according to the present invention.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a side view showing a usage limit of the chip.

FIG. 5 is a side view of a chip formed by a conventional method.

FIG. 6 is a sectional view of a forging die in a conventional method.

FIG. 7 is a cross-sectional view of a chip forged by a conventional method.

FIG. 8 is a perspective view showing formation of a usage limit indicator by a conventional method.

[Explanation of symbols]

 1: Lower mold 2: Upper mold 4: Ridges 10: Chip 11: Usage limit display

Claims (1)

Claim: What is claimed is: 1. A forging die comprising a combination of an upper die and a lower die, a forming portion corresponding to a usage limit indicating portion of a spot welding tip is formed on an inner surface of the lower die, and the forging die is formed. A method for forming a spot welding tip, characterized in that the use limit indicator is integrally formed on an outer surface of the spot welding tip during forging by using the spot welding tip.