JP2547793Y2 - Spot welding equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spot welding apparatus for joining various parts pressed on a body of a vehicle body, and more particularly, to an intermediate electrode used for preventing an indentation at a welding point.

[0002]

2. Description of the Related Art In general, a spot welding apparatus sandwiches two electrodes on both sides of a joint of two parts by pressure contact.
Since a large welding current is applied locally to perform spot welding, indentations are formed on the surface of the component.
Therefore, Japanese Utility Model Application Laid-Open No. 63-71981 and Japanese Utility Model Application Laid-Open No.
In the prior art of Japanese Patent Application Laid-Open No. 3-71982, an intermediate electrode is interposed between the electrode and the component to prevent the occurrence of an indentation.

Conventionally, a spot welding apparatus using the above-mentioned intermediate electrode is constructed as shown in FIG. That is,
When a predetermined part 1 of the vehicle body is joined at a predetermined point A on the periphery of the inner 2 and the outer 3 which is pressed as shown in the drawing, a direct electrode is applied to the point A of the inner 2 which is not visible inside. 23 are contacted. Further, another electrode 24 is brought into contact with the hitting point A of the outer 3 through the intermediate electrode 22 ′, and the three electrodes 22 ′ and 2.
A large welding current I is passed between the inner and outer members 3 and 24 so as to spot-weld the spot A. Here, since the intermediate electrode 22 'increases the contact area with the outer 3 at the time of spot welding to prevent the occurrence of indentation, the intermediate electrode 22' needs to have a predetermined size, and the intermediate electrode 22 'has a contact surface 22a'. However, it is finished and machined so as to conform to its shape in a wide range extending over the hitting portion A and the bent portion 3a of the outer 3.

[0004]

However, in the above-mentioned conventional device, the intermediate electrode 22 'must be formed in conformity with a wide range of the shape of the outer member 3.
At the use location 2 ', it is necessary to machine each of them separately to form a shape conforming to a predetermined shape, and the number of processing steps is increased, resulting in an increase in cost.
In recent years, thick-plated steel sheets have tended to be used as the outer 3. However, in this case, the plating on the surface of the outer 3 becomes hot at the time of welding and is melted. was there.

[0005] The present invention has been made in view of these points, and is intended to improve the workability of the intermediate electrode and to reduce the maintenance cost and cost of the intermediate electrode while taking into account the use of thick plated steel sheets. The purpose is to prevent the plating from being dissolved and adhered.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a method in which an electrode is directly contacted on one side of a connecting point of two parts, and the other side is connected via an intermediate electrode. In a spot welding device that welds by contacting the electrodes, it has a metal cooling support with good thermal conductivity, and covers only the vicinity of the part where the part is hit from the cooling support. While extending a good intermediate electrode, etc., the intermediate electrode is detachably fixed to the concave portion of the cooling support, and a cooling passage through which cooling water is always supplied near the intermediate electrode fixing portion of the cooling support. It is characterized by forming.

[0007]

According to the above structure, the intermediate electrode prevents spots from being formed by the intermediate electrode during spot welding of the two parts. At this time, the intermediate electrode is cooled with a large cooling capacity together with the cooling support, whereby the intermediate electrode is cooled. Even if the shape covers only the vicinity of the hit point, the thermal effect on the component is extremely reduced, and the penetration of plating into the intermediate electrode does not occur. Also, the intermediate electrode is detachably fixed to the cooling support, and the intermediate electrode is cooled indirectly via the cooling support, so that replacement of the intermediate electrode is easy, and Since the structure of the intermediate electrode as a product is not complicated, it is effective in terms of maintenance and cost.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. 1 to 3, reference numeral 10 denotes a spot welding device, which has a metal cooling support 11 such as a steel material which also serves as a cooling passage and an intermediate electrode support. This cooling support 1
Reference numeral 1 denotes a plate having a predetermined thickness, and a concave portion 12 for accommodating and installing the intermediate electrode 22 is formed in an upper portion. Are formed, and a mounting arm 14 is provided on these sides. Then, such a cooling support 11 causes the mounting arm 14 to play with
It is mounted vertically with 6 and nut 17.

Connection fittings 18 and 19 are attached to the lower end and the front opening of the cooling passage 13, respectively, and the hose 20 of the connection fitting 18 at the lower end is connected to the water supply side of the cooling water pipe, and the hose 21 of the front connection fitting 19 is connected. Are connected to the drain side respectively,
The cooling water can flow through the cooling passage 13 to directly cool the cooling support 11. The intermediate electrode 22 is, for example, an alloy of copper and chromium, and is made of a material having excellent electrical conductivity, thermal conductivity, durability, etc., and has a square electrode having a minimum necessary surface area and thickness sufficient to prevent indentation. A portion 22a is provided, and a thin mounting portion 22b is provided below the electrode portion 22a. Then, such an intermediate electrode 22 fits the mounting portion 22 b in close contact with the lower heat transfer surface 12 a in the concave portion 12 of the cooling support 11, and removably fixes the mounting portion 22 b with the bolt 25. It is mounted so as to protrude above the cooling support 11.

In this way, two electrodes 23 and 24 are disposed on both sides of the intermediate electrode 22 mounted on the cooling support 11 so as to face each other. Then, at the point A of the inner 2 and the outer 3 of the predetermined part 1 of the vehicle body, one electrode 23 is directly in contact with the point A of the inner inner 2,
The other electrode 24 is brought into contact with the hit point A of the outer 3 through the intermediate electrode 22 so as to appear outside, and spot welding is performed in this state.

Next, the operation of this embodiment will be described. First, when performing spot welding, the hoses 20 and 21 must be set in advance.
The cooling water is always supplied to the cooling passage 13 of the cooling support 11 by the cooling water, and the cooling support 11 and the intermediate electrode 22 mounted directly above the cooling support 11 in contact with the heat transfer surface 12a or the like, It is efficiently cooled to a predetermined low temperature. Then, when a predetermined part 1 of the vehicle body is conveyed to the position of the intermediate electrode 22 and positioned on a production line or the like, one electrode 23 is provided on the inner 2 and the intermediate electrode 22 is provided on the outer 3.
, The other electrodes 24 are held in contact with each other with a predetermined pressing force and welded, and thus the inner 2 and the outer 3 are integrally connected. At this time, the surface of the outer 3 is in contact with the intermediate electrode 22 having a large surface area and is energized in a distributed manner, thereby preventing the formation of indentations.

Also, during the spot welding, the intermediate electrode 2
2 is cooled with a large cooling capacity together with its cooling support 11, so that even if it is heated when the welding current I is supplied, its temperature rise is suppressed. Therefore, even if the intermediate electrode 22 is large enough to cover the hitting portion A, the thermal effect of the intermediate electrode 22 on the outer 3 is very small, and thus the deformation of the outer 3 is avoided. In addition, when the temperature of the intermediate electrode 22 is low, when a thick-plated steel plate is used as the outer 3, the dissolution of the plating is very small. According to the experiment, the temperature at the time of welding the conventional intermediate electrode is approximately 60 degrees, but according to the cooling support of the present invention, the temperature is cooled to approximately 40 to 50 degrees, and the above effect can be sufficiently exhibited. confirmed. If the intermediate electrode 22 is worn and deteriorated due to long-term use, the intermediate electrode 22 can be easily replaced with a new one by loosening the bolt 25.

Although the embodiment of the present invention has been described above, the shape of the intermediate electrode, the cooling support, the path of the cooling passage, and the like are not limited thereto.

[0014]

[Effects of the Invention] As described above, according to the present invention,
In a spot welding apparatus having an intermediate electrode, since the intermediate electrode is configured to be constantly cooled, the thermal effect on parts during welding is extremely reduced, and therefore, the intermediate electrode has a small shape only in the vicinity of the spot. However, it is possible to reliably prevent the occurrence of thermal distortion or the like in the component. Since all of the intermediate electrodes can be formed into a common rectangular shape or the like, this machining becomes very easy, mass production can be achieved, and costs can be reduced. Due to the decrease in the temperature of the intermediate electrode, even in the case of a thick-plated steel sheet, the dissolution of the plating is reduced, the quality can be maintained, and the durability of the intermediate electrode itself increases. Since the intermediate electrode is fixed to the cooling support in which the cooling passage is formed, the cooling capacity is large, and the intermediate electrode is detachably fixed to the recess by a bolt, so that the exchangeability and the heat conductivity are good.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of a spot welding apparatus according to the present invention.

FIG. 2 is a front view of a portion including an intermediate electrode and a cooling support.

FIG. 3 is a plan view of the same.

FIG. 4 is a side view showing an example of a conventional spot welding apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body part 2 Inner 3 Outer 10 Spot welding apparatus 11 Cooling support body 12 Depression 13 Cooling passage 22 Intermediate electrode 23, 24 Electrode

Claims (2)

(57) [Scope of request for utility model registration] 1. A spot welding apparatus in which an electrode is directly contacted on one side of a connecting point of two parts and another electrode is contacted on the other side via an intermediate electrode to weld the spot.
It has a metal cooling support with good thermal conductivity, and covers only the vicinity of the part where the part is hit from the cooling support.
An intermediate electrode having good thermal conductivity or the like is extended, and the intermediate electrode is detachably fixed to the concave portion of the cooling support, and cooling water is constantly supplied to the vicinity of the intermediate electrode fixing portion of the cooling support. A spot welding apparatus characterized by forming a cooling passage. 2. The spot welding apparatus according to claim 1, wherein said intermediate electrode is closely fixed to a heat transfer surface near said cooling passage in said recess.