JP2001009575A - Electrode structure for spot welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode structure for spot welding which can fully secure a coupling force of an electrode chip and a shank, surely prevent leakage of electrode cooling water, and facilitate attachment/detachment of the electrode chip. SOLUTION: A taper face 18c is formed to a shank connecting part 18b of an electrode chip 18, and the tip inner face of the shank connecting part 18b is pressure-engaged with a welding shank 12, to which a taper face 12a being engageable with the taper face 18c of the shank connecting part 18b is formed. At the tip of the welding shank 12, a tapered male thread part 12b is formed, into which the tip end of the welding shank 12 is screwed by a sleeve 22 having a tapered female thread 22a. As a result, the coupling force of the shank connecting part 18b and the welding shank 12 is reinforced, so as to surely prevent detachment of the electrode chip 18 and leakage of the cooling water. Furthermore, by the screw releasing operation of the sleeve 22, the electrode chip 18 can be easily detached from the welding shank 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode structure for spot welding, and more particularly, to an electrode structure for strengthening a bonding force between an electrode tip and a welding shank to prevent the electrode from falling off and to prevent electrode water leakage.
The present invention relates to an improvement in an electrode structure for spot welding that can be easily pulled out when replacing an electrode tip.

[0002]

2. Description of the Related Art Conventionally, in the process of assembling an automobile body, a welding process is arranged at various places, and a robot welding device, a manual welding device, and the like sequentially perform welding at predetermined welding locations. Spot welding is performed by sandwiching a welding portion of a work with a pair of electrodes and applying a predetermined electric power. FIG. 3 shows a schematic configuration diagram of a welding gun 100 for spot welding. In this welding gun 100, a pair of electrode arms 104 each having an electrode tip 102 at a tip of a shank 104a is fixed to be rotatable about a shaft 106. When welding a workpiece to be welded, the electrode tips 102 at the tips of the pair of electrode arms 104 sandwich a welding portion of the workpiece, and in this sandwiched state, supply a predetermined amount of power to the electrode tip 102. This is done by: Also, during welding, the electrode 102 becomes extremely hot, so that the electrode tip 102 is constantly circulated and supplied with electrode cooling water from the gun body 108 side via the electrode arm 104 to cool the electrode tip 102 from the inside. In addition, the electrode tip 102 is prevented from being damaged and the welding efficiency is prevented from lowering.

The electrode tip 102 is a consumable part. For example, when the electrode tip 102 is used about 1,000 times, the tip is worn out, so that proper welding cannot be performed. Therefore, the electrode tip 102 needs to be replaced after a predetermined number of uses or a predetermined time. As shown in FIG. 4, the conventional electrode tip 102 has a female shape having a tapered portion 102a whose diameter decreases toward the inside,
It was press-fitted into the tapered portion 104b formed on the shank 104a side. As described above, the shank 104a
The supply pipe 112 for supplying the electrode cooling water is accommodated in the inside, and the electrode cooling water that has cooled the electrode chip 102 is collected from a gap around the supply pipe 112. At this time, it is important to prevent the electrode cooling water from leaking. However, as described above, the electrode chips 102 are press-fitted to prevent leakage.

[0004] As a mounting structure of the electrode tip 102, for example, there is a method of joining the electrode tip and the shank using a screw as disclosed in Japanese Utility Model Application Laid-Open No. 6-77979. According to this configuration, the electrode tip can be easily attached and detached as compared with the press-fitting described above, so that the workability of replacing the electrode tip can be improved.

[0005]

However, when the former press-fitting method is used for mounting the electrode tip, if the electrode tip is welded to the workpiece on the side to be welded during the welding operation, the electrode arm must be mounted. There is a problem that the electrode tip falls off the shank during the opening operation. The detachment of the electrode tip leads to the leakage of the electrode cooling water, resulting in the stoppage of the welding equipment and the damage to the side to be welded. Conversely, when replacing the electrode tip, there is also a problem that the electrode tip in the press-fitted state cannot be easily removed from the shank. On the other hand, when the latter connection method using a screw is used, a predetermined bonding force can be secured between the electrode tip and the shank, so there is no fear of falling off due to welding as described above. Water leakage cannot be avoided, and electrode cooling water cannot be supplied directly to the electrode tip. Therefore, the electrode cooling water can be supplied only to the vicinity of the electrode tip, that is, to the vicinity of the shank tip, and the cooling is indirect and cannot be efficiently performed. As a result, there is a problem that it is not possible to satisfactorily prevent damage to the electrode tip and prevent a decrease in welding efficiency.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to ensure a sufficient bonding force between an electrode tip and a shank to prevent the electrode tip from falling off and to reliably prevent leakage of electrode cooling water. It is another object of the present invention to provide an electrode structure for spot welding, which can easily attach and detach an electrode tip.

[0007]

In order to achieve the above object, the present invention provides an electrode comprising a tip weld and a shank connection, wherein the shank connection is connected to the tip weld. An electrode tip having a cooling space for supplying cooling water to the tip welding portion, and a hollow shank having a cooling water supply / discharge channel inside, the tip having a tapered shape gradually becoming thicker toward the tip. A welding shank in which a taper capable of fitting with the taper of the shank connection portion is formed on the inner peripheral surface, and a tapered male screw portion whose diameter gradually decreases toward the distal end is formed on the distal outer peripheral surface. And a sleeve having a female screw portion having a tapered shape that can be screwed into a male screw portion formed at the tip of the welding shank.

According to this configuration, the taper of the shank connection portion is fitted to the taper on the side of the welding shank, and the fitting portion is further tightened by screwing the sleeve over the fitting portion. As a result, it is possible to increase the coupling force of the fitting portion, and it is possible to reliably prevent the electrode tip from falling off and to prevent the cooling water from leaking.

In order to achieve the above object, according to the present invention, in the above structure, a flange is formed on the shank connection portion side of the electrode tip, and the sleeve is connected to the flange when the sleeve is released from the screw engagement. The contact electrode tip is removed from the welding shank.

According to this structure, the electrode tip press-fitted into the welding shank can be easily removed, and the workability of replacing the electrode tip is improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings.

FIG. 1 is a partial sectional view of a disassembled state showing a tip portion of a welding gun for spot welding to which an electrode structure for spot welding 10 of the present embodiment is applied. The conventional welding gun shown in FIG. 3 can be used.

As shown in FIG. 1, a welding shank 12 is fixed to the tip of the electrode arm 104. The welding shank 12 has a hollow pipe shape so that a supply pipe 14 for supplying the electrode cooling water can be inserted therein and a drain passage 16 for collecting the electrode cooling water supplied around the supply pipe 14 can be formed. Is presented. The supply pipe 14 and the drain passage 16 are connected to an electrode cooling water supply / discharge device (not shown) on the welding device main body side via the inside of the electrode arm 104.

The welding shank 12 has a tapered surface 12a formed on the inner peripheral surface on the distal end side, which expands toward the end. On the other hand, the outer peripheral surface of the distal end side of the welding shank 12 has a tapered male screw portion 12b whose diameter gradually increases from the end.
Are formed.

An electrode tip 18 is fitted and inserted into the inner peripheral surface on the distal end side of the welding shank 12. This electrode tip 1
Reference numeral 8 denotes a tip welded portion 18a and a shank connection portion 18b integrally formed with the tip welded portion 18a. The shank connecting portion 18b is formed thinner than the tip welding portion 18a, and has an outer peripheral surface on the side of the tip welding portion 18a such that the shank connecting portion 18b can be closely fitted to the tapered surface 12a of the inner peripheral surface on the distal end side of the welding shank 12. A tapered surface 18c that gradually becomes thicker is formed. Further, inside the shank connection portion 18b, a flow passage hole 20 is formed as a cooling space through which the electrode cooling water can flow toward the tip welding portion 18a. Therefore, in a state where the shank connecting portion 18b and the welding shank 12 are tightly fitted, the electrode cooling water supplied from the welding shank 12 side is not used.
8b, it is directly guided into the inside of the tip welding portion 18a, and after directly cooling the tip welding portion 18a from the inside, it can be led to the drain passage 16 of the welding shank 12, thereby circulating the electrode cooling water. be able to.

Prior to the connection between the shank connection portion 18b and the welding shank 12, the tapered male screw portion 12b of the welding shank 12 is connected to the tapered male screw portion 12b.
The sleeve 22 on which the tapered female screw portion 22a that can be screwed with b is formed is mounted. The outer surface of the sleeve 22 preferably has a nut shape or the like (however, it is sufficient if there is a surface on which the spanner or the like catches) in order to facilitate a screwing operation with a fastening tool (for example, a spanner or the like).
Then, after the shank connecting portion 18b is press-fitted to the welding shank 12, if the sleeve 22 is further tightened, the coupling force between the shank connecting portion 18b and the welding shank 12 can be further enhanced. In the experiment, the shank connection portion 18b, ie, the electrode tip 18 and the welding shank 12 were tightened by tightening the tapered sleeve 22.
It was confirmed that the binding force was about twice as large as when not used.

FIG. 2 shows a state in which the electrode tip 18 and the sleeve 22 are mounted on the welding shank 12. In this state,
The actual welding operation is performed. The same spot welding electrode structure 10 is applied to the pair of electrode arms 14 in FIG.

When the electrode tip 18 is replaced due to abrasion or the like, the screwing of the sleeve 22 is released (the sleeve 22 is loosened), so that the sleeve 22 is connected to the tip welding portion 18a and the shank connecting portion 18b. The electrode tip 18 comes into contact with the flange 18d formed in the portion, and is pushed up in a direction to pull out from the welding shank 12. Therefore, the electrode tip 18 can be easily removed only by loosening the sleeve 22 by using a wrench or the like.

As described above, according to the present embodiment, it is possible to sufficiently secure the bonding force between the electrode tip 18 and the welding shank 12, prevent the electrode tip from falling off, and reliably prevent the electrode cooling water from leaking. And then the electrode tip 18
Can be easily attached and detached.

The shape of the electrode tip, the shape of the welding shank, and the like shown in the present embodiment are arbitrary except for the connection portions, and may be selected as appropriate according to the workpiece to be welded. The same effect as described above can be obtained.

[0021]

According to the present invention, the taper of the shank connection portion is fitted to the taper of the welding shank side, and the fitting portion is tightened by screwing the sleeve over the fitting portion. , It is possible to increase the joining force of the fitting portion,
It is possible to reliably prevent the cooling water from leaking and to prevent the electrode chips from falling off. Further, the electrode tip can be easily removed from the welding shank by releasing the screw of the sleeve.

[Brief description of the drawings]

FIG. 1 is an exploded explanatory view showing a partial cross section for explaining a spot welding electrode structure according to an embodiment of the present invention.

FIG. 2 is an assembly explanatory view showing a partial cross section for explaining a spot welding electrode structure according to an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a conventional welding gun.

FIG. 4 is an explanatory view illustrating a conventional connection structure between an electrode tip and a shank.

[Explanation of symbols]

10 electrode structure for spot welding, 12 shank for welding, 12a, 18c tapered surface, 12b tapered male thread portion, 14 supply pipe, 16 drainage channel, 18 electrode tip, 18a tip welding portion, 18b shank connection portion,
20 channel hole, 22 sleeve, 22a tapered female thread, 104 electrode arm.

Claims (2)

[Claims] 1. An electrode comprising a tip welding portion and a shank connection portion, wherein the shank connection portion has a tapered shape that gradually becomes thicker toward a connection portion with the tip welding portion, and has an inner portion with respect to the tip welding portion. An electrode tip having a cooling space for supplying cooling water, and a hollow shank having a cooling water supply / discharge flow path therein, and a taper which can be fitted to the taper of the shank connection portion is formed on a tip inner peripheral surface. The outer peripheral surface of the distal end has a tapered male thread portion having a tapered shape whose diameter gradually decreases toward the distal end, and a male shank formed at the distal end of the welding shank. An electrode structure for spot welding, comprising: a sleeve having a female screw portion having a tapered shape. 2. The electrode structure according to claim 1, wherein a flange is formed on the shank connection portion side of the electrode tip, and the sleeve comes into contact with the flange when the sleeve is released from being screwed, and the electrode tip is welded. Electrode structure for spot welding, characterized in that it comes off from the shank.