JP5707591B1 - Spot welding electrode - Google Patents

Abstract

Provided is an electrode for spot welding capable of preventing leakage of cooling water filled in a holder and a shank when replacing a cap tip of a spot welder. Spot welding in which a cap chip 3 is attached to the tip of the holder 1 via a shank 2, and a circulation channel 4 of cooling water for cooling the cap chip 3 is formed inside the holder 1 and the shank 2. Water stop valve device 5 having a water stop function, which is an electrode for use and can prevent leakage of cooling water from the tip opening 6 when the cap chip 3 is removed between the shank 2 and the cap chip 3. Attached. The water stop valve device 5 includes a tubular valve body 7, a tubular float valve 8, a tubular shower plug 9, and a stop valve 10.

Description

  The present invention relates to an electrode for spot welding that can prevent leakage of cooling water filled in a holder and a shank when replacing a cap tip of a spot welder.

Conventionally, spot welders have been widely used, for example, when welding automobile bodies and the like. Further, as the welding electrode, as shown in FIG. 6, an electrode in which a cap chip 3 is attached to the tip of the holder 1 via a shank 2 is used. In this spot welding machine, the work is sandwiched between the upper and lower electrodes, and the work is melted and welded with electric resistance heat by pressurizing and energizing, so that the cap chip 3 may be exposed to heat and welded to the work. .
Therefore, in general, an electrode for spot welding in which a cooling water circulation channel 4 for cooling the cap chip 3 is formed inside the holder 1 and the shank 2 is used to prevent the cap chip 3 from being welded.

On the other hand, if the cap chip 3 is used for a long time, the shape of the tip part is deformed due to the applied pressure or wear and causes welding failure. Therefore, the cap chip 3 used more than a predetermined number of hit points. Had to be replaced.
However, when the cap chip 3 is removed from the shank 2, there is a problem that the cooling water inside the water pressure is ejected and the periphery is flooded.

Then, even if the cap chip 3 is removed, an electrode for spot welding is proposed in which a water stop valve is attached so that the cooling water filled in the holder 1 and the shank 2 can be prevented from being ejected (for example, (See Patent Document 1 and Patent Document 2).
However, what is described in Patent Document 1 and Patent Document 2 is a structure in which the water stop valve is operated by electrical control, which requires an electrical control device, wiring, and the like, complicates the electrode device, and increases the manufacturing cost. There was also a problem of becoming higher. In addition, since the water stop valve is installed in the cooling water introduction part of the holder 1, even if the valve is closed and the cap chip 3 is removed, the cooling water in the holder 1 and the shank 2 which are on the tip side of the valve There was a problem that it could not be prevented from leaking.

Japanese Patent Laid-Open No. 11-58029 International Publication Number WO2009 / 019742

  The present invention solves the above-mentioned problems and can prevent the cooling water filled in the holder and the shank from leaking out when the cap tip of the spot welder is replaced. To provide a spot welding electrode which is a valve device having a simple structure that can be easily incorporated into the tip of a shank, and which can be made inexpensive without requiring an electric control device or wiring. It is the purpose.

In the spot welding electrode of the present invention made to solve the above-described problems, a cap tip is attached to the tip of the holder via a shank, and cooling water for cooling the cap tip is placed inside the holder and the shank. the circulation flow path be formed, between the shank and the cap tip, when removing the cap chip, a water stop valve apparatus having a water stop function which can prevent the distal end opening portion exiting cooling water leaks An electrode for spot welding attached , wherein the water stop valve device includes a tubular valve body having an upper end as a fitting portion with a shank and a lower end as a mounting portion with a cap chip, and an inner portion of the valve body. A cylindrical float valve that is movable in the direction, with the inside as the outgoing path for cooling water and the outside as the return path for cooling water, and interposed between the lower end of the shank and the upper end of the float valve A cylindrical shower plug that introduces the cooling water in the shank into the float valve, and is mounted inside the lower end of the float valve. When the cap chip is removed, it is pushed down by the spring force of the spring. The valve body is made of a stop valve that closes the front end opening of the valve body and is pushed up against the spring force of the spring during welding to open the front end opening of the valve body. Is.

The spring is mounted between the shower plug and the stop valve, and it is preferable that the stop valve is always urged downward, and this is the invention according to claim 2 .

A pin that can contact the inner bottom surface of the cap chip protrudes from the end of the stop valve, and the stop valve moves up and down in the float valve in accordance with the attachment / detachment of the cap chip. Preferably, this is the invention according to claim 3 .

  In the invention according to claim 1, the cap chip is attached to the tip of the holder via the shank, and the circulation path for cooling water for cooling the cap chip is formed inside the holder and the shank. As a welding electrode, a water stop valve device having a water stop function capable of preventing leakage of cooling water from the opening of the tip when the cap tip is removed is attached between the shank and the cap tip. The cooling water can be stopped at the tip of the shank, and when the cap chip is replaced, it is possible to reliably prevent the cooling water filled in the holder and the shank from leaking out.

In the invention according to claim 1 , the water stop valve device includes a tubular valve body having an upper end as a fitting portion with a shank and a lower end as a mounting portion with a cap chip, and the inside of the valve body in the axial direction. And is interposed between a lower end portion of the shank and an upper end portion of the float valve, and is disposed between the lower end portion of the shank and the upper end portion of the float valve. A cylindrical shower plug that introduces cooling water into the float valve, and is attached to the inside of the lower end of the float valve. When the cap chip is removed, it is pushed downward by the spring force of the spring to open the tip of the valve body It is made up of a stop valve that is pushed up against the spring force of the spring and opens the tip opening of the valve body during welding. It can easily be incorporated into the distal end of the shank for a valve device having a simple structure that operates, also can be made unnecessary electric control device, wirings and the like as in the prior art.

In the invention according to claim 2 , since the spring is mounted between the shower plug and the stop valve, and the stop valve is always urged downward, it is easy to obtain the spring elasticity. Also, a simple structure can be obtained.

In the invention according to claim 3 , a pin capable of contacting the inner bottom surface of the cap chip protrudes from the tip of the stop valve, and the stop valve moves up and down in the float valve according to the attachment / detachment of the cap chip. Since it is configured to do so, the stop valve is moved up and down according to whether the cap chip is attached or not. As a result, the electrode tip opening can be reliably closed when the cap chip is replaced, and the cooling water can be prevented from leaking.

It is sectional drawing which shows embodiment of this invention. It is sectional drawing of the principal part which shows the state where a cap chip | tip is not mounted | worn. It is sectional drawing of the principal part which shows the state which mounted | wore with the cap chip | tip. It is sectional drawing of the principal part which shows the time of welding. It is an AA arrow line view of FIG. It is sectional drawing which shows the electrode for spot welding of a prior art.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of an electrode for spot welding according to the present invention. In the figure, 1 is a straight cylindrical holder, 2 is a shank attached to the tip of the holder 1, and 3 is a cap. Chip. A cooling water circulation passage 4 for cooling the cap chip 3 is formed inside the holder 1 and the shank 2.
Further, in the figure, 4a is a cooling water forward path, 4b is a cooling water return path, 4c is a cooling water supply port, 4d is a cooling water discharge port, and 4e is a cooling water supply pipe.

  The above structure is basically the same as that of the conventional spot welding electrode. However, in the present invention, when the cap chip 3 is removed between the shank 2 and the cap chip 3, the cooling water is supplied from the tip opening 6. It has the structure where the water stop valve apparatus 6 which has the water stop function which can prevent leaking out was attached. As shown in FIG. 2, the water stop valve device 5 includes a tubular valve body 7, a tubular float valve 8, a tubular shower plug 9, a stop valve 10, and a spring 11. ing.

Hereinafter, each of the components will be described.
The cylindrical valve body 7 is made of, for example, a beryllium alloy or a chrome zirconium copper alloy. A taper portion 7a is formed on the inner peripheral surface of the upper end portion, and is a fitting portion at the lower end portion of the shank 2, while a taper portion 7b is formed on the outer peripheral surface of the lower end portion, and the cap The mounting portion of the chip 3 is used. Further, a step portion 7c for mounting a shower plug 9 described later is formed in the central portion inside the valve body 7, and a lower plug portion of the float valve 8 described later is further formed on the inner peripheral surface of the lower end. 7d is formed in close contact with the bulge.

  The cylindrical float valve 8 is mounted inside the valve body 7 so that the valve body 7 is movable in the axial direction. Further, the float valve 8 has an inner side as a forward path for cooling water and an outer side as a return path for cooling water. Further, an outer tapered portion 8a is formed on the outer periphery of the lower portion of the float valve 8, and the cooling water return passage 4b can be closed in close contact with the bulging portion 7d of the valve body 7. In addition, although the inner side taper part 8b is formed in the lower part inner periphery, this point is mentioned later.

  The tubular shower plug 9 is interposed between the lower end portion of the shank 2 and the upper end portion of the float valve 8, and introduces cooling water in the shank into the float valve. The shower plug 9 includes a large-diameter plug upper portion 9a and a small-diameter plug lower portion 9b. The lower end surface of the plug upper portion 9a is mounted on the stepped portion 7c of the valve main body 7 and attached to the valve main body 7. . A cooling water supply pipe 4e is connected to the center of the upper portion 9a of the plug, and as shown in FIG. 5, six communication holes 9c are formed radially on the outer peripheral edge. The communication hole 9c is for introducing the supplied cooling water into the return path 4b.

The stop valve 10 is mounted inside the lower end of the float valve 8 and controls the opening and closing of the tip opening 6 of the valve body 7. The stop valve 10 is formed with a tapered portion 10 a on the lower outer peripheral surface, and is configured to close the tip opening 6 by being in close contact with the inner tapered portion 8 b of the float valve 8.
In the illustrated example, a spring 11 is mounted between the shower plug 9 and the stop valve 10 so that the stop valve 10 is always biased downward. When the cap chip 3 is removed, the stop valve 10 is pushed downward by the elastic force of the spring 11 to close the tip opening 6 of the valve body 1, while the stop valve 10 is spring-loaded during welding. The tip opening 6 is opened by being pushed up against the resilience of 11.

A pin 10b that abuts the inner bottom surface of the cap chip 3 protrudes from the tip of the stop valve 10, and the pin 10b moves up and down as the cap chip 3 is attached / detached. 10 is configured to move up and down in the float valve 8.
The float valve 8, the shower plug 9, and the stop valve 10 are made of polyoxymethylene resin (POM), which is excellent in heat resistance, wear resistance, and lubricity, and generally called Duracon or polyacetal. preferable.

Next, the operation of the water stop valve device 6 configured as described above will be described with reference to FIGS.
FIG. 2 is a cross-sectional view of the main part showing a state where the cap chip is not attached.
In this state, the stop valve 10 is pushed downward by the elastic force of the spring 11, and the tapered portion 10a and the inner tapered portion 8b of the float valve 8 are in close contact with each other. Further, since the float valve 8 is also pushed downward, the outer taper portion 8a on the outer periphery of the lower portion and the sticking portion 7d on the inner peripheral surface of the lower end of the valve body 7 are in close contact with each other. As a result, the front end opening 6 of the valve body 1 is completely closed, and no cooling water leaks.

FIG. 3 is a cross-sectional view of the main part showing a state where the cap chip 3 is mounted.
In this case, since the pin 10b is pushed upward on the inner bottom surface by mounting the cap chip 3, the stop valve 10 is pushed upward against the elastic force of the spring 11. As a result, the taper portion 10a of the stop valve 10 and the inner taper portion 8b of the float valve 8 are released from close contact, and the back surface side of the cap chip 3 communicates with the cooling water supply pipe 4e. It will be cooled with water.
In this state, since the cooling water supply pump (not shown) is not operated, the cooling water is in a stagnation state without being circulated.

FIG. 4 is a cross-sectional view of the main part showing the time of welding.
In this case, the supply pump is activated and the cooling water flows in the order of the shower plug 9 and the float valve 8 from the supply pipe 4e. When a certain amount of cooling water flows in, the float valve 8 is moved upward by the pressure of the flowing cooling water, and the bulging portion 7d of the valve body 7 and the outer tapered portion 8a of the float valve 8 are released. It will be. As a result, the cooling water having cooled the inner bottom surface of the cap chip 3 is guided to the cooling water return path 4b formed by the inner wall surface of the valve body 7 and the outer wall surface of the float valve 8, and then the shower plug 9 It will be guided into the holder 1 through the communication hole 9c.
After that, after being discharged to the outside from the cooling water discharge port 4d and cooled, it is supplied from the cooling water supply port 4c and circulated again as in the conventional case. By forming the cooling water circulation passage 4 in this manner, the cap chip 3 is efficiently cooled during welding.

Next, the case where the cap chip 3 is replaced will be described.
In this case, the operation of the cooling water supply pump is stopped, and the used cap chip 3 is removed from the valve body 7. As a result, the force forcibly pushing up the pin 10b disappears, and the stop valve 10 is pushed down by the elastic force of the spring 11, so that the tapered portion 10a and the inner tapered portion 8b of the float valve 8 are brought into close contact with each other. In this state, the stop valve 10 is further pushed down, and the outer tapered portion 8a on the outer periphery of the lower portion of the float valve 8 and the sticking portion 7d on the inner peripheral surface of the lower end of the valve body 7 are in close contact (see FIG. 2).
As a result, the tip opening 6 of the valve body 1 is completely closed, so that no cooling water leaks. Therefore, when the cap chip 3 is replaced as in the prior art, the cooling water filled in the holder 1 and the shank 2 does not leak and the work place is not flooded, so that a good working environment is ensured. Can do.

In addition, after removing the used cap chip 3 as described above and before attaching a new cap chip 3 (so-called standby), the cooling water supply pump is operated by timer control or the like, and cooling is performed. Water pressure may increase. However, in the present invention, as described above, since the valve body 7, the float valve 8, and the stop valve 10 are pressed by the elastic force of the spring 11 so that the tip opening 6 is completely closed, the cooling water does not flow. There is no leakage.
Further, after the replacement with the new cap chip 3, the cooling water circulation passage 4 is formed as shown in FIG. 4, so that the cap chip 3 is sufficiently cooled and the welding process is efficiently performed. Will be.

  As is clear from the above description, in the present invention, when the cap chip is removed between the shank and the cap chip, the water stop valve having a water stop function capable of preventing the cooling water from leaking from the tip opening. Since the apparatus is attached, it is possible to prevent the cooling water filled in the holder and the shank from leaking out when the cap chip is replaced. In addition, since a mechanically operated valve device is used, it can be easily incorporated into the tip of the shank, and compared to the conventional case where a valve is installed at the cooling water inlet of the holder 1. Cooling water leakage can be minimized. Furthermore, there is an advantage that an electric control device, wiring, etc. are not required and can be made inexpensive.

DESCRIPTION OF SYMBOLS 1 Holder 2 Shank 3 Cap chip 4 Circulating flow path 4a Outward path 4b Return path 4c Cooling water supply port 4d Cooling water discharge port 4e Cooling water supply pipe 5 Water stop valve device 6 Tip opening 7 Valve body 7a Taper 7b Taper Part 7c Step part 7d Swelling part 8 Float valve 8a Outer taper part 8b Inner taper part 9 Shower plug 9a Plug upper part 9b Plug lower part 9c Communication hole 10 Stop valve 10a Taper part 10b Pin 11 Spring

Claims (3)

A cap chip is attached to the tip of the holder via a shank, and a cooling water circulation passage for cooling the cap chip is formed inside the holder and the shank .
When the cap chip is removed between the shank and the cap chip, an electrode for spot welding to which a water stop valve device having a water stop function capable of preventing leakage of cooling water from the tip opening is attached ,
The water stop valve device has a tubular valve body having an upper end as a fitting portion with a shank and a lower end as a mounting portion with a cap chip,
A cylindrical float valve that is movable in the axial direction in the valve body, has an inner side as a cooling water forward path, and an outer side as a cooling water return path;
A cylindrical shower plug interposed between the lower end of the shank and the upper end of the float valve to introduce cooling water in the shank into the float valve;
It is mounted inside the lower end of the float valve, and when the cap chip is removed, it is pushed downward by the spring force of the spring to close the tip opening of the valve body. An electrode for spot welding characterized by comprising a stop valve that is pushed up to open the tip opening of the valve body .   The spot welding electrode according to claim 1, wherein the spring is mounted between the shower plug and the stop valve, and always biases the stop valve downward.   2. A pin that abuts the inner bottom surface of the cap chip protrudes from the tip of the stop valve, and the stop valve is configured to move up and down in the float valve in accordance with the attachment / detachment of the cap chip. Or the electrode for spot welding of 2.

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