JPH09155563A - Electrode for spot welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the tip part of a shank from being damaged due to the dropout of a chip, to allow a coolant to flow smoothly and to improve the cooling efficiency of the chip by providing a small clearance in the conical hollow hole of the chip and fitting a heat resistant and pressure resistant electrical insulating protective body into the bore of a supply tube. SOLUTION: A chip 2 is formed with a conical hollow hole 7, in which a small clearance 10 is provided communicating with a coolant passage 5a and its return passage 5b and in which a heat resistant and pressure resistant electrical insulating protective body 9 is fitted in the bore; therefore, the tip part of a shank 1 is protected from being damaged by the protective body 9 even if the chip 2 is dropped out from the shank 1. In addition, the small clearance 10 in the hollow hole 7 of the chip 2 by means of the protective body 9 performs an orifice action with the passage area drawn and narrowed; as a result, the coolant flows at high speed in the heat generating part of the chip 2, performing heat exchange, thereby improving the cooling efficiency of the chip 2.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrode for spot welding.

[0002]

2. Description of the Related Art In a spot welding electrode in which a tip is taper-fitted to the tip of a shank, the tip is welded to the work piece and removed from the shank. Since the tip of the shank is damaged due to this, in order to prevent this, a spot welding electrode having a hat-type protective member made of a pressure-resistant electrical insulating material is arranged at the tip of the shank.
No. 108489.

Although not disclosed in Japanese Utility Model Laid-Open No. 60-108489, in the spot welding electrode, in order to cool the heat generation of the tip, a coolant supply pipe is penetrated into the shank and the inside of the supply pipe is Forming a coolant supply passage,
A spot welding electrode in which a gap between the supply pipe and the inner wall of the shank forms a cooling liquid return passage, and a tip having a conical hollow hole is fitted to the tip end of the shank is, for example, an actual open-circuit sho.
It is well known from the number 3-2581.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the spot welding electrode provided with a cooling means known in No. 81, in order to prevent the tip portion of the shank from being damaged by the removal of the tip, a protective member made of a hat-type pressure-resistant electric insulating material is used. When it is arranged at the tip of the shank, as shown in FIG. 2, the cooling liquid supply pipe 4 penetrates into the shank 1, and the inside of the supply pipe 4 has a cooling liquid supply passage 5a.
And a gap between the supply pipe 4 and the inner wall of the shank 1 forms a cooling liquid return passage 5b, and a protection member 6 made of a hat-type pressure-resistant electric insulating material is inserted and mounted in the cooling liquid return passage 5b. Then, the tip 2 of the shank 1 is fitted with the tip 2 having the conical hollow hole 7 at the tip portion of the tapered surface 3 to form a spot welding electrode.

In this case, it is possible to prevent the tip portion of the shank 1 from being damaged by the removal of the tip 2 by the hat-shaped protection member 6 and to suppress the heat generation of the tip 2 with the cooling liquid. Since 6 is inserted and mounted in the cooling liquid return passage 5b, the passage area of the cooling liquid return passage 5b at the portion where the protection member 6 is inserted and attached is narrowed and narrowed, and the protection member 6 is inserted and inserted. In the cooling liquid return passage 5b in the mounted portion, an orifice action occurs and the pressure becomes high, so that the fluid resistance increases and the smooth flow of the cooling liquid is obstructed, and T1 of the conical hollow hole 7 of the chip 2 is increased. There is a problem in that the cooling liquid remains in the area of 1) and the cooling efficiency of the chip 2 is reduced.

In view of the above problems, an object of the present invention is spot welding in which the tip of the shank is prevented from being damaged due to the removal of the tip and the cooling liquid is allowed to flow smoothly to improve the cooling efficiency of the tip. Is to provide an electrode for use.

[0007]

In order to achieve the above object, the structure of the present invention is such that a cooling liquid supply pipe is penetrated into a shank and the inside of the supply pipe forms a cooling liquid supply passage. The gap with the inner wall of the shank forms the cooling liquid return passage,
In a spot welding electrode in which a tip having a conical hollow hole is fitted to the tip of the shank, a small gap that connects the cooling liquid supply passage and the cooling liquid return passage to the conical hollow hole of the tip A protective body made of a heat-resistant and pressure-resistant electric insulating material is fitted into the inner diameter of the supply pipe.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 is a shank, and a taper surface 3 into which a chip 2 is fitted is formed at a tip end portion thereof. A cooling liquid supply pipe 4 penetrates through the shank 1, the inside of the supply pipe 4 forms a cooling liquid supply passage 5a, and the gap between the supply pipe 4 and the inner wall of the shank 1 forms a cooling liquid return passage 5b. ing.

A conical hollow hole 7 is formed in the tip 2, and a small gap 10 for communicating the cooling liquid supply passage 5a and the cooling liquid return passage 5b is provided in the conical hollow hole 7. A protective body 9 made of a heat-resistant and pressure-resistant electric insulating material is fitted into the inner diameter of the supply pipe 4.

The protective member 9 is provided with a fitting portion 9a for fitting with the inner diameter of the supply pipe 4, and the fitting portion 9a is provided.
A passage hole 9b which communicates the cooling liquid supply passage 5a with the gap 10 penetrates a.

Since the present invention has the above-described structure, even if the tip 2 is pulled out from the shank 1, the tip of the shank 1 is prevented from being damaged by the protective member 9.

Further, in cooling the chip 2, the cooling liquid supplied from the cooling liquid supply passage 5a enters the gap 10 through the passage hole 9b of the protective body 9 and cools the chip 2 which generates heat by welding. And is returned through the cooling liquid return passage 5b.

Therefore, in the present invention, since the small gap 10 of the conical hollow hole 7 of the tip 2 formed by the protective body 9 narrows the passage area to perform an orifice action, the cooling liquid is generated in the heat generating portion of the tip 2. Flow at a high speed for heat exchange, and the residual area T2 of the cooling liquid is in the cooling liquid supply passage 5a separated from the conical hollow hole 7 of the chip 2 due to the fluid resistance of the portion of the gap 10, so that the chip 2 Does not adversely affect the cooling efficiency.

[0014]

As described above, according to the present invention, it is possible to prevent damage to the tip of the shank due to withdrawal of the tip, and
This has the advantage of improving the cooling efficiency of the chip by allowing the cooling liquid to flow smoothly.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electrode for spot welding of the present invention.

FIG. 2 is a sectional view showing a conventional spot welding electrode.

[Explanation of symbols]

 1 Shank 2 Tip 3 Tapered Surface 4 Coolant Supply Pipe 5a Coolant Supply Passage 5b Coolant Return Passage 7 Conical Hollow Hole 9 Protective Body 9a Fitting 9b Passage Hole 10 Gap

Claims (1)

[Claims] 1. A cooling liquid supply pipe is penetrated into the shank, the inside of the supply pipe forms a cooling liquid supply passage, and a gap between the supply pipe and an inner wall of the shank forms a cooling liquid return passage, and a tip of the shank. In a spot welding electrode in which a tip having a conical hollow hole is fitted in a portion, the conical hollow hole of the tip has a small gap for communicating the cooling liquid supply passage and the cooling liquid return passage. An electrode for spot welding, wherein a protective body made of a heat-resistant and pressure-resistant electric insulating material to be fitted is fitted to the inner diameter of the supply pipe.