JP2013107133A - Electrode for spot welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode for spot welding which allows a welding tip used for a welding gun of a spot welding machine to be easily replaced without leakage of cooling water during replacement and has high cooling effect.SOLUTION: A cooling water shutoff device 5 is internally arranged at an electrode rod shank 2 mounted on a tip of a welding gun body 12. A valve element 6 and a valve seat 8 abut on or separate from each other by spring pressure of a spring member 7 urging the valve element 6 of the cooling water shutoff device 5 by attaching/detaching the welding tip 1, so that cooling water is released or shut off.

Description

  The present invention relates to an electrode for spot welding used in a spot welding gun.

  A welding tip that is attached to the tip of a welding gun of a spot welder and pressurizes and welds an object to be welded, such as a steel plate, needs to be replaced with a new one as a consumable item after repeated use. Moreover, since the welded part of spot welding becomes very high temperature, the welding tip prevents heat generation by circulating cooling water in the welding gun and the electrode.

  FIG. 6 shows a basic cooling structure of a conventional spot welding electrode. As shown in FIG. 6, the conventional spot welding electrode includes an electrode bar shank 2 attached to the tip of the welding gun body 12, and a water supply pipe 3 coaxially disposed in the electrode bar shank 2. The cap-shaped welding tip 1 is detachably fitted to the tapered portion 15 on the outer periphery of the tip end portion of the electrode bar shank 2.

  Since the welding tip 1 is a consumable item, it is detached with a tool or the like and replaced with a new one. In use, the welding tip 1 is cooled by circulating circulation of cooling water sequentially sent from the welding gun body 12 side to the water supply pipe 3 and the cooling water passage hollow portion 4 between the electrode rod shank 2 and the water supply pipe 3. Is done. 6A shows a state when the welding tip 1 is mounted, and FIG. 6B shows a state when the welding tip 1 is removed.

  As shown in FIG. 6A, the cooling water penetrates to the bottom surface 14 on the inner side of the welding tip 1, so that the cooling effect is good. However, the problem here is that when the welding tip 1 is removed for replacement, the tip of the electrode rod shank 2 is opened, and the cooling water remaining inside the welding gun leaks out. Naturally, the cooling water circulation device is stopped when the welding tip 1 is replaced. However, the cooling water remaining inside the welding gun or the electrode rod shank 2 overflows due to the opening of the tip of the electrode rod shank 2 and is cooled. Leakage of water to the outside is inevitable. Therefore, at the time of exchanging the welding tip, the present situation is that a bucket for receiving the cooling water is prepared under the welding gun, and there is a problem that complicated work is required.

  Measures have been proposed in the past to solve these problems. For example, a configuration in which the tip of the electrode rod shank is closed so that the cooling water passage does not open to the outside (see, for example, Patent Document 1), or an opening / closing that opens and closes the cooling water passage at the tip opening of the electrode rod shank. The thing provided with the valve mechanism (for example, patent document 2, patent document 3) is devised.

  However, each of the cases shown in the above prior art documents has a problem. In the case of Patent Document 1, since the cooling water is completely blocked in the electrode bar shank, there is a problem that the cooling effect is poor because the welding tip cannot be directly cooled. Further, in the case of Patent Document 2, since a specially shaped welding tip having a protrusion protruding abnormally at the center must be used, there is a problem that a commercially available one cannot be used. In addition, productivity is difficult, and it is very expensive and difficult to use. In the example of Patent Document 3, the cooling water channel is a device with a special welding gun having a water supply hole and a drain hole, and there is a problem that it cannot be applied to a commercially available electrode rod shank having versatility.

  Therefore, the inventors of the present invention have previously proposed Patent Document 4 to solve the above-described problems.

JP-A-7-68387 Japanese Utility Model Publication No. 4-475 Japanese Utility Model Publication No. 63-174777 JP 2011-173152 A

  The present invention has been made in order to solve the above-described problem in the same manner as in Patent Document 4, and in the replacement of a welding tip for spot welding, the welding tip can be replaced without leakage of cooling water, and is commercially available as a consumable product. It is an object to provide a spot welding electrode that enables the use of standard welding tips. The present invention proposes a method for solving the above-mentioned problem that differs from Patent Document 4.

The solution means described below describes four embodiments.
First, the method in the first embodiment will be described.
An electrode bar shank for removably fitting a hat-shaped welding tip around the outer periphery of the tip;
A water supply pipe arranged coaxially in the electrode rod shank;
A valve seat fitted to the inner peripheral surface of the tip of the electrode rod shank;
A valve body disposed so that the outer end protrudes outward from the tip of the electrode rod shank in a state of being detachably fitted to the valve seat;
A spring member biased to move the valve body outward of the tip of the electrode rod shank;
In the spot welding electrode, wherein the valve body is disposed so as to face the outflow side opening surface of the water supply pipe, and the inner end surface thereof is inclined with respect to the outflow side opening surface of the water supply pipe. An electrode for spot welding characterized in that an opening / closing part with which the valve seat contacts and separates is constituted by a spherical surface.

The method in the second embodiment will be described below.
The electrode bar shank for removably fitting the hat-shaped welding tip on the outer periphery of the tip,
The water supply pipe disposed coaxially in the electrode rod shank;
A valve seat fitted to the inner peripheral surface of the tip of the electrode rod shank;
A valve body disposed so that the outer end protrudes outward from the tip of the electrode rod shank in a state of being detachably fitted to the valve seat;
The spring member biased to move the valve body outward of the tip of the electrode rod shank; and
In the spot welding electrode, wherein the valve body is disposed so as to face the outflow side opening surface of the water supply pipe, and the inner end surface thereof is inclined with respect to the outflow side opening surface of the water supply pipe. An electrode for spot welding characterized in that an opening / closing part with which the valve seat contacts and separates is constituted by a seating surface.

The method in the third embodiment will be described below.
An electrode bar shank for removably fitting a hat-shaped welding tip around the outer periphery of the tip;
A water supply pipe arranged coaxially in the electrode rod shank;
A valve seat fitted to the inner peripheral surface of the tip of the electrode rod shank;
A valve body disposed so that the outer end protrudes outward from the tip of the electrode rod shank in a state of being detachably fitted to the valve seat;
A coil spring member biased to move the valve body outward of the tip of the electrode rod shank;
In the spot welding electrode, the valve body is disposed so as to face the outflow side opening surface of the water supply pipe, and the inner end surface thereof is inclined with respect to the outflow side opening surface of the water supply pipe.
An electrode for spot welding, wherein the valve seat is formed in a shape having a flange portion having a two-sided width.

The method in the fourth embodiment will be described below.
An electrode bar shank for removably fitting a hat-shaped welding tip around the outer periphery of the tip;
A water supply pipe arranged coaxially in the electrode rod shank;
A valve seat fitted to the inner peripheral surface of the tip of the electrode rod shank;
A valve body disposed so that the outer end protrudes outward from the tip of the electrode rod shank in a state of being detachably fitted to the valve seat;
Add a burying prevention member to the valve body so that the valve body is not buried in the electrode rod shank,
In the spot welding electrode, wherein the valve body is disposed so as to face the outflow side opening surface of the water supply pipe, and the inner end surface thereof is inclined with respect to the outflow side opening surface of the water supply pipe. An electrode for spot welding characterized in that the opening / closing part to which the valve seat contacts and separates is configured by a taper, a spherical surface, or a seating surface.

  Basically, the above three methods are the same, and only the shapes of the valve seat and the valve body are different. Specifically, when the valve body provided in the center of the valve seat built at the tip of the electrode rod shank is fitted with a welding tip, a gap is formed between the valve seat and the valve body, so that the cooling water Structure that can secure a passage and remove the welding tip, the valve body is pushed down by the spring member, the opening and closing part where the valve body and the valve seat come into contact is separated, the gap disappears and the cooling water is shut off And Only the fourth embodiment has a simplified structure in which the spring member is removed and only the burying prevention member is provided.

  By using the electrode of the present invention, the cooling water can be shut off, and the welding tip can be easily replaced without leakage of the cooling water.

It is explanatory drawing which shows Example 1 of this invention, (a) is sectional drawing which shows the state at the time of mounting | wearing of the welding tip 1, (b) is sectional drawing which shows a state when the welding tip 1 is removed, (c) ) Is a bottom view of (b). It is an expanded sectional view which shows the direction of the flow of the cooling water at the time of use of the Example, (a) is sectional drawing which shows the state at the time of mounting | wearing with the welding tip 1, (b) is a state when the welding tip 1 is removed. FIG. It is explanatory drawing which expands and shows the coupling | bonding state of the valve body 6 and the spring member 7 of the Example. It is explanatory drawing of attachment and removal of the valve seat 8 of the Example, (a) is an Example of slotted countersunk shape of a minus groove, (b) is an example of an irregular (hexagonal) hole countersunk shape, (c ) Is a sectional view of the valve seat 8 and is an enlarged view. It is explanatory drawing which shows Example 2 of this invention, (a) is sectional drawing which shows the state at the time of mounting | wearing with the welding tip 1, (b) is sectional drawing which shows a state when the welding tip 1 is removed, (c) ) Is a bottom view of (b). It is a figure which shows the conventional electrode for spot welding, (a) is sectional drawing which shows the state at the time of mounting | wearing with the welding tip 1, (b) is sectional drawing which shows a state when the welding tip 1 is removed. It is explanatory drawing which shows Example 3 of this invention, (a) is sectional drawing which shows the state at the time of mounting | wearing of the welding tip 1, (b) is sectional drawing which shows a state when the welding tip 1 is removed, (c) ) Is an enlarged perspective view of the valve seat 8 of the third embodiment. It is explanatory drawing which shows Example 4 of this invention, (a) is sectional drawing which shows the state at the time of mounting | wearing of the welding tip 1, (b) is sectional drawing which shows a state when the welding tip 1 is removed, (c) ) Is a bottom view of (b).

  The structure of the present invention is shown in Figs.

  FIG. 1 shows the spot welding electrode of Example 1, (a) shows the state when the welding tip 1 is mounted, (b) shows the state when the welding tip 1 is removed, and (c) shows ( The bottom of b) is shown.

  The spot welding electrode of Example 1 is configured as follows. That is, the electrode rod shank 2 in which the cap-shaped welding tip 1 is removably fitted on the outer periphery of the tip portion, the water supply pipe 3 disposed coaxially in the electrode rod shank 2, and the tip of the electrode rod shank 2 The valve seat 8 fitted on the inner peripheral surface of the electrode portion is disposed so that the outer end portion protrudes outward from the tip end portion of the electrode bar shank 2 in a state in which the valve seat 8 is detachably fitted to the valve seat 8. And a spring member 7 biased so as to move the valve body 6 outward of the tip end portion of the electrode rod shank 2. The valve body 6 is disposed so as to face the outflow side opening surface of the water supply pipe 3, and its inner end surface is inclined with respect to the outflow side opening surface of the water supply pipe 3.

  The procedure for replacing the welding tip 1 will be described. FIG. 1A shows a state in which the welding tip 1 is mounted. As can be discriminated from this figure, since the valve body 6 is pushed up by the inner bottom surface 14 of the welding tip 1, a gap is formed between the valve seat 8 and a passage of cooling water is secured, and the cooling water Reaches the bottom surface 14 inside the welding tip 1. Further, the spring member 7 in this state is crushed and deformed, and is in a state of being loaded.

  As shown in FIG. 3, the valve body 6 has an inclined portion 11 formed at the upper head. This is to make the flow of cooling water from the water supply pipe 3 smoother. By having the inclined portion 11, the water flow 9 shown by the arrow in FIG. 2A can be secured, the cooling water penetrates into the narrow passage, and the cooling water reaches the bottom surface 14 on the inner side of the welding tip 1 to provide a cooling effect. To increase. Further, as shown in FIG. 3, the valve body 6 and the spring member 7 have a component configuration in which they are integrally coupled by caulking or molding. In the first embodiment, a metal leaf spring is used as the spring member 7. This leaf spring has a fixed portion mounted on the outer end surface of the valve body 6 and four arms extending from the peripheral edge of the fixed portion toward the distal end surface of the electrode bar shank 2.

  The welding tip 1 and the electrode bar shank 2 are fitted in a press-fitted state at the respective taper portions 15 shown in FIG. However, since the welding tip 1 is a consumable item, if the number of times of use increases, the life of the welding tip 1 will be lost due to wear or the like, and the welding tip 1 must be replaced. When the welding tip 1 is removed with a tool or the like, the valve body 6 is pushed down by the spring force of the deformed spring member 7, and the outer diameter spherical surface portion 21 of the valve body 6 shown in FIG. 3 and the valve shown in FIG. The inner spherical surface portion 22 of the seat 8 is in close contact as shown in FIG. 2B, and the cooling water is shut off.

  When the welding tip 1 is again inserted into the tip of the electrode rod shank 2 for loading a new welding tip 1, the valve body 6 is now pushed up by the bottom surface 14 inside the welding tip 1, as shown in FIG. 2 (a). A gap is formed between the valve seat 8 and the cooling water, and the cooling water reaches the bottom surface 14 inside the welding tip 1. Therefore, the cooling water sequentially supplied from the water supply pipe 3 becomes a water flow 9 indicated by an arrow in FIG. 2A, and the cooling water circulates while passing through the bottom surface 14 inside the welding tip 1. Therefore, even if the welding tip 1 generates heat by spot welding, the cooling effect is maintained as in the conventional electrode of FIG.

  FIG. 4 shows a specific usage example of the method for attaching and detaching the valve seat 8. A negative shaped counterbore hole 18 is formed on the lower end face of the valve seat 8. The valve seat 8 is attached and detached by inserting and rotating a minus driver of the tool into the minus-shaped counterbore hole 18. Similarly, the valve seat 8 is attached to and detached from the hexagonal counterbore hole 19 by rotating it with another tool. The hexagonal countersunk holes 19 may have other irregular shapes such as squares and pentagons. Further, in the first embodiment, the valve seat 8 and the electrode rod shank 2 are joined by forming a pipe taper screw which is usually used. However, other joining methods such as the outer diameter of the valve seat 8 and the electrode rod shank are used. The inner diameter of 2 may be configured only by press fitting.

FIG. 5 shows the spot welding electrode of Example 2, (a) shows the state when the welding tip 1 is mounted, (b) shows the state when the welding tip 1 is removed, and (c) shows ( The bottom of b) is shown.

  Embodiment 2 in FIG. 5 is configured by changing the spherical surface of the opening / closing portion where the valve body 6 and the valve seat 8 of FIG. 1 in FIG. 1 contact and separate to a seat surface, and the valve body 6 and the valve seat 8 are in the shape of FIG. And different. Other configurations and operations are the same as those of the first embodiment shown in FIG.

  FIG. 7 shows the spot welding electrode of Example 3, (a) shows the state when the welding tip 1 is mounted, (b) shows the state when the welding tip 1 is removed, and (c) shows this state. It is an expansion perspective view of the valve seat 8 of Example 4. FIG.

The valve seat 8 in the third embodiment forms a flange portion 24, and the fitting with the valve body 6 is screwed with a screw. As shown in the perspective view of the valve body 6 in (c), since the flange portion 24 of the valve seat 8 is provided with a cut portion having a two-side width, it can be attached and detached with a spanner or the like.
Further, the electrode rod shank 2 needs to be used in various sizes depending on the size of the welding tip 1. Particularly when the welding tip 1 is used in a small diameter size, the thickness of the fitting portion of the electrode rod shank 2 that is screwed with the valve seat 8 becomes thin. Using a fine metric screw instead of a screw eliminates the strength problems.
Further, the coil spring member 10 is loaded to enhance the cooling water blocking effect, and the E-type retaining ring 23 is attached to the end portion to prevent the coil spring member 10 from falling off as in the fourth embodiment.

  FIG. 8 shows the spot welding electrode of Example 4, (a) shows the state when the welding tip is mounted, (b) shows the state when the welding tip is removed, and (c) shows (b). The bottom is shown.

  In Example 4 of FIG. 8, the spring member 7 of Example 1 of FIG. 1 is deleted. Furthermore, only the E-type retaining ring 23 is added as a member for preventing the embedment of the valve body 6 in the electrode rod shank 2, and the other configuration is the same as that of the first embodiment shown in FIG. However, since there is no spring pressure in the cooling water shutoff due to the close contact between the valve body 6 and the valve seat 8 and only the internal cooling water and the own weight of the valve body 6 shut off, It lacks barrier properties. However, it is a simple and effective method in a small space by increasing the weight of the valve body 6 as a metal having a high specific gravity such as a copper alloy. Further, although the E-type retaining ring 23 is used in the fourth embodiment shown in FIG. 8, other retaining rings or press-fitted small-diameter pins may be used for the purpose of merely preventing burial.

  The electrode for spot welding according to the present invention can be widely used as an electrode for easily replacing a welding tip in all spot welding machines.

DESCRIPTION OF SYMBOLS 1 Welding tip 2 Electrode rod shank 3 Water supply pipe 4 Cooling water passage hollow part 5 Cooling water shut-off device 6 Valve body 7 Spring member 8 Valve seat 9 Water flow 10 Coil spring member 11 Inclined part 12 Welding gun main body 14 Bottom face 15 Taper part 18 Negative shape counterbore hole 19 Hexagonal counterbore hole 21 Spherical surface of outer diameter 22 Spherical surface of inner diameter 23 E-type retaining ring 24 Head

Claims (5)

An electrode bar shank for removably fitting a hat-shaped welding tip around the outer periphery of the tip;
A water supply pipe arranged coaxially in the electrode rod shank;
A valve seat fitted to the inner peripheral surface of the tip of the electrode rod shank;
A valve body disposed so that the outer end protrudes outward from the tip of the electrode rod shank in a state of being detachably fitted to the valve seat;
A spring member biased to move the valve body outward of the tip of the electrode rod shank;
In the spot welding electrode, the valve body is disposed so as to face the outflow side opening surface of the water supply pipe, and the inner end surface thereof is inclined with respect to the outflow side opening surface of the water supply pipe.
An electrode for spot welding characterized in that an open / close portion where the valve body and the valve seat come into contact with each other is formed of a spherical surface. The electrode bar shank for removably fitting the hat-shaped welding tip on the outer periphery of the tip,
The water supply pipe disposed coaxially in the electrode rod shank;
A valve seat fitted to the inner peripheral surface of the tip of the electrode rod shank;
A valve body disposed so that the outer end protrudes outward from the tip of the electrode rod shank in a state of being detachably fitted to the valve seat;
The spring member biased to move the valve body outward of the tip of the electrode rod shank; and
In the spot welding electrode, the valve body is disposed so as to face the outflow side opening surface of the water supply pipe, and the inner end surface thereof is inclined with respect to the outflow side opening surface of the water supply pipe.
An electrode for spot welding characterized in that an opening / closing part where the valve body and the valve seat come into contact with each other is formed by a seating surface. An electrode bar shank for removably fitting a hat-shaped welding tip around the outer periphery of the tip;
A water supply pipe arranged coaxially in the electrode rod shank;
A valve seat fitted to the inner peripheral surface of the tip of the electrode rod shank;
A valve body disposed so that the outer end protrudes outward from the tip of the electrode rod shank in a state of being detachably fitted to the valve seat;
A coil spring member biased to move the valve body outward of the tip of the electrode rod shank;
In the spot welding electrode, the valve body is disposed so as to face the outflow side opening surface of the water supply pipe, and the inner end surface thereof is inclined with respect to the outflow side opening surface of the water supply pipe.
An electrode for spot welding, wherein the valve seat is formed in a shape having a flange portion having a two-sided width. An electrode bar shank for removably fitting a hat-shaped welding tip around the outer periphery of the tip;
A water supply pipe arranged coaxially in the electrode rod shank;
A valve seat fitted to the inner peripheral surface of the tip of the electrode rod shank;
A valve body disposed so that the outer end protrudes outward from the tip of the electrode rod shank in a state of being detachably fitted to the valve seat;
Add a burying prevention member to the valve body so that the valve body is not buried in the electrode rod shank,
In the spot welding electrode, wherein the valve body is disposed so as to face the outflow side opening surface of the water supply pipe, and the inner end surface thereof is inclined with respect to the outflow side opening surface of the water supply pipe. An electrode for spot welding characterized in that the opening / closing part to which the valve seat contacts and separates is configured by a taper, a spherical surface, or a seating surface.   The negative or irregular shaped counterbore hole is formed on one end face of the valve seat, a tool is inserted into these holes, and the valve seat is attached and detached by rotating. 2. The electrode for spot welding according to 2.