JPH073875U - Spot welding equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce operating costs and improve welding workability in spot welding equipment using an intermediate electrode. In a spot welding apparatus in which an intermediate electrode 10 is interposed on the side of either one of a pair of electrodes 1 and 2 arranged opposite to each other, a tip of the intermediate electrode 10 has a single welding point. As the work contact surface 12a having an area capable of covering the work piece, and the rear end surface as the electrode contact surface 11f, which is movable by the support member 7 in the direction of coming into contact with and separating from the work 3 and does not rotate about the movement axis. Support in the state. With such a configuration, on the surface of the work 3 on the side of the intermediate electrode 10, the electrode pressing force is supported by the intermediate electrode 10 at the non-melted portion outside the melted portion of the members to be joined 4, 5, so that welding marks are generated. Disappears. Further, since there is no careless rotation of the intermediate electrode 10 during the welding work, the adhesion between the workpiece contact surface 12a of the intermediate electrode 10 and the workpiece 3 is maintained well, and highly reliable welding is realized. It

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a spot welding apparatus in which an intermediate electrode is interposed between one of a pair of electrodes arranged to face each other so as to be able to contact and separate with a work sandwiched between the work and the work.

[0002]

[Prior art]

 The spot welding device arranges a work consisting of a plurality of members to be joined to each other between a pair of electrodes that are arranged so as to be able to come into contact with and separate from each other, and presses and clamps the work from both sides thereof with the pair of electrodes. By applying a predetermined voltage between the two electrodes, the respective members to be joined of the work are locally melted and joined. Therefore, in this case, since a pressing force is applied to the fusion-bonded portion of the work by both electrodes, concave welding marks are formed on both sides of this welded portion.

By the way, in recent years, particularly in the field of automobiles, when automobile parts are manufactured by spot welding under the influence of high-grade tastes of users, the welding marks on the part exposed to the outside and visible are particularly automobiles. It is required to eliminate as much as possible because it will reduce the product value of.

From such a background, for example, in Japanese Utility Model Laid-Open No. 2-148786, in spot welding, a material such as copper is used as a backing metal member between a surface of a workpiece where a welding mark is disliked and an electrode corresponding thereto. A thick plate-shaped intermediate electrode made of a conductive material is interposed, a work is pressed and sandwiched by a pair of electrodes through the intermediate electrode, and a voltage is applied between these electrodes to generate welding marks on the intermediate electrode side. A technique has been proposed in which each member to be joined of the above work is locally welded without performing the welding. That is, by contacting the intermediate electrode and the work over a wide range and supporting the pressing force by the electrode on the non-melting part outside the melting part of the work, the pressing force is locally applied to the melting part. By avoiding this, the generation of welding marks is prevented in advance.

[0005]

[Problems to be solved by the device]

 By the way, when spot welding is performed using such a thick plate-shaped intermediate electrode, as disclosed in the above-mentioned publicly known examples, the intermediate electrode has a size such that it can simultaneously cover a plurality of welding points. In addition, it is customary to make the surface shape of the contact surface on the work side match the surface shape of the work. Here, it is necessary to form the intermediate electrode in such a size that it can cover multiple welding spots at the same time. If the intermediate electrode is attached / detached for each welding spot, it takes time to change the setup work. This is because the efficiency decreases, so that the arrangement of the intermediate electrode can be completed with one setup change operation for multiple welding spots. In addition, the surface shape of the contact surface of the intermediate electrode to the work side should be matched with the surface shape of the work piece if the work piece and the intermediate electrode are not in close contact at each welding point. This is because it is possible that a molten metal layer formed between the members cannot be formed and exfoliation occurs later, so this is prevented.

On the other hand, in spot welding, a voltage is applied between a pair of electrodes to join the welded parts of the work by the resistance heat, and theoretically the part with the highest contact resistance, that is, the pair Only the contact points between the members to be joined of the workpieces located on the straight line connecting the electrodes should be melted, and resistance heat should not be generated between the intermediate electrode and the workpieces. However, in reality, in the case where continuous welding is performed due to the conduction heat from the molten portion, the temperature of the intermediate electrode becomes high, and it gradually wears out during long-term use. Further, when the intermediate electrode is worn in this way, a gap is created between the intermediate electrode and the work, so that an arc is generated there and a vicious cycle occurs such that the wear of the intermediate electrode is further increased. It is also possible.

Therefore, when such a state is reached, it is necessary to rework the intermediate electrode so as to recover the state in which the surface shape of the intermediate electrode and the surface shape of the work are matched. However, in this case, even if the portion in which the above-mentioned inconvenience occurs is one of the plurality of welding spots covered by the intermediate electrode, the intermediate electrode has a thick plate shape. However, it is impossible to selectively rework only this inconvenient part to match the entire surface of the intermediate electrode to the work surface shape, and therefore, it is not possible to rework one of the welding points. Even in the case where the processing may be performed, the entire intermediate electrode must be reprocessed, which may result in problems such as increased maintenance man-hours and high operating costs.

In view of the above, the present invention aims to reduce operating costs by improving maintainability in a spot welding apparatus using an intermediate electrode, and at the same time improve workability in welding work. It was made as.

[0009]

[Means for Solving the Problems]

 As a concrete means for solving such a problem in the invention of the present application, in the invention of claim 1, a pair of electrodes are arranged facing each other so as to be able to come in contact with and separate from each other in a direction of sandwiching a work in the plate thickness direction. In the spot welding apparatus in which any one of the electrodes of the above-mentioned electrodes is brought into direct contact with the above-mentioned work, and the other electrode is brought into contact with the above-mentioned work through the intermediate electrode, The electrode has a tip end surface as a work contact surface having an area that can cover a single welding point, and a rear end surface as the electrode contact surface 1, which can be moved in a direction in which the electrode contacts and separates from the work. It is also characterized in that it is supported in a non-rotating state around the movement axis.

According to a second aspect of the invention, in the spot welding apparatus according to the first aspect, the intermediate electrode is detachably attached to an electrode body supported by the supporting member and a tip end portion of the electrode body. It is characterized in that it is configured with a tip whose front end surface is the work contact surface.

According to a third aspect of the present invention, in the spot welding apparatus according to the first or second aspect, a plurality of the intermediate electrodes are attached to the support member, and the workpiece contact surfaces of the plurality of intermediate electrodes are attached. The surface shape of is matched with the surface shape of the portion of the workpiece corresponding to each of the intermediate electrodes.

[0012]

[Action]

 With each of the inventions of the present application, the following actions can be obtained with such a configuration.

According to the first aspect of the present invention, the intermediate electrode is disposed at the front position of one of the electrodes in the pressing direction, is movable by the supporting member in the electrode pressing direction, and is supported in the non-rotating state about the moving axis. The work is placed between the work contact surface and the other electrode opposite to the work contact surface. In this state, move the pair of electrodes in the approaching direction, press the electrode contact surface of the intermediate electrode with one of the electrodes, and push it forward to bring the work contact surface to one surface of the work. The other electrode is pressed and brought into direct contact with the other surface of the work so as to sandwich the work between the intermediate electrode and the other electrode. Here, when a predetermined voltage is applied between the pair of electrodes, a current flows between the pair of electrodes through the intermediate electrode, and the joined portion of each joined member of the workpiece having the largest contact resistance has resistance. Both are melted by heat and welded together.

In this case, on the surface of the work on the side where the intermediate electrode is arranged, the work contact surface of the intermediate electrode may cover a single welding point, specifically, the cross-sectional area of the nugget. Since it has a larger area, the pressing force by the electrode is supported by the non-melted portion outside the melted portion of the member to be joined on the surface of the workpiece on the side of the intermediate electrode. No welding mark is formed on the electrode, and a welding mark is formed only on the surface on the other electrode side.

Further, since the surface shape of the work contact surface of the intermediate electrode needs to be closely adhered to the surface of the corresponding work, when the surface shape of the work is non-planar (for example, curved surface shape) In order to match this, it is formed in a non-planar shape, but in this case, since the intermediate electrode is supported by the supporting member in a non-rotating state, the intermediate electrode rotates during welding work, and It is possible to surely avoid the loss of adhesion between the surface and the work contact surface of the intermediate electrode.

According to the second aspect of the invention, in addition to the above-described action, the following unique operation can be obtained. That is, since the intermediate electrode has a divided structure of an electrode main body supported by a supporting member and a tip attached to the tip of the electrode main body to form a workpiece contact surface, for example, the above-mentioned If the contact surface of the workpiece gradually wears, the tip can be reused without any work by replacing the tip with a new one or reworking the tip.

According to the third aspect of the invention, the following unique action can be obtained in addition to the above-mentioned action. That is, since a plurality of intermediate electrodes are attached to the supporting member, and the work contact surfaces of the respective intermediate electrodes are matched with the surface shapes of the corresponding works, the above supporting member is attached to the work. Position once, it is possible to perform welding at multiple welding spots by sequentially moving a pair of electrodes to each intermediate electrode side, and the same work as when using a conventional thick plate intermediate electrode is performed. Is ensured.

Further, in this case, since the intermediate electrode is provided for each welding spot, for example, the adhesion to the work is impaired at any one of the plurality of welding spots, and the favorable welding is performed. If it becomes impossible to secure all the welds, by replacing only the intermediate electrode that has this problem or reworking the tip, all welding can be performed without changing the other intermediate electrodes. It is possible to recover good weldability at the spot.

Further, since each of the intermediate electrodes is arranged corresponding to each of a plurality of welding spots on the work, the operator is required to perform the welding by operating the welding gun by hand. By applying the electrode to the intermediate electrode, it is possible to reliably perform welding at each welding spot.For example, when a conventional thick plate intermediate electrode is used, the operator operates the welding gun. Prior to this, it is not necessary to mark the position of the intermediate electrode that seems to be the welding point and move the welding gun with this mark as a mark.

[0020]

[Effect of device]

 Therefore, according to the spot welding devices of the inventions of the present application, the following effects can be obtained.

(A) According to the spot welding apparatus of the first aspect, by using the intermediate electrode having the work contact surface having an area capable of covering a single welding point, the work surface on the side of the intermediate electrode is used. By preventing welding marks, the commercial value of the welded product as a product is enhanced.

Further, since deterioration of the adhesion between the work surface and the work contact surface of the intermediate electrode due to the careless rotation of the intermediate electrode during the welding work is prevented, the reliability is high and the accuracy is high. A good weld can be obtained.

(B) According to the spot welding apparatus of the second aspect, in addition to the effect of the (a), an electrode body in which the intermediate electrode is supported by the support member and a tip having a work contact surface are provided. By adopting a divided structure, for example, when the work contact surface wears out due to long-term use, only the tip is replaced with a new one, or this tip is reprocessed, and the electrode body is Since it can be reused without any modification, there is an effect that the operating cost can be reduced as compared with, for example, the case of replacing the entire intermediate electrode.

(C) According to the spot welding apparatus of the third aspect, in addition to the effects of the above (a) and (b), a plurality of intermediate electrodes are attached to the support member and their respective work contact surfaces are attached. By matching the surface shape of the work to a plurality of welding spots by a single positioning operation, it is possible to continuously perform welding, and it is possible to secure high welding workability. is there.

Further, since the intermediate electrode is provided for each welding point and the maintenance can be performed for each intermediate electrode, each welding point as in the case of using the conventional thick plate-shaped intermediate electrode The maintenance cost can be reduced compared to the case where the maintenance cannot be performed for each.

Furthermore, by arranging each intermediate electrode corresponding to each of a plurality of welding spots on the workpiece, it is possible to perform accurate welding at each welding spot, particularly in the case of manual welding, which is highly reliable and accurate. It is possible to improve the quality of welded products, which in turn makes good welding possible.

[0027]

【Example】

 Hereinafter, the spot welding apparatus of the present invention will be specifically described with reference to the accompanying drawings. FIG. 1 shows a main part of a spot welding apparatus Z according to an embodiment of the present invention. The spot welding device Z includes a first electrode 1 and a second electrode 2 which are arranged to face a welding gun (not shown) so as to be able to come into contact with and separate from each other, and an intermediate electrode assembly 9 described later.

As shown in FIGS. 1 and 2, the intermediate electrode assembly 9 has a flat plate-shaped intermediate electrode holder 7 (which is detachably fixed to the support frame 6 by fixing bolts 8, 8, ... A plurality of intermediate electrodes 10, which will be described later, (five in this embodiment) are attached in a predetermined arrangement pattern to the supporting member in the claims).

As shown in FIGS. 3 and 4, the intermediate electrode 10 has a two-part structure including an electrode body 11 and a chip 12.

The electrode main body 11 is integrally formed of a copper rod body having a diameter larger than that of each of the electrodes 1 and 2, and a body portion 11a located at an axially middle portion thereof is provided in the intermediate electrode holder. On the other hand, the tip portion 11b is formed into a taper shape that gradually reduces its diameter toward the tip side while supporting the tip portion 11b so that a tip 12 described later can be attached thereto. The rear end portion 11c of the electrode body 11 is formed to have a diameter larger than the body portion 11a by a predetermined dimension, and the rear end surface thereof is an electrode contact surface 11f with which the first electrode 1 contacts. A shoulder portion 11d is formed at a continuous portion of the rear end portion 11c and the body portion 11a.

Further, the electrode body 11 is provided with two cooling water passages 23, 23 formed in an L shape from the outer peripheral surface of the rear end portion 11c to the front end surface 11e of the front end portion 11b. At the same time, a cooling water inlet pipe 21 and a cooling water outlet pipe 22 are attached to the respective end portions of the cooling water passages 23, 23 on the rear end 11c side.

The electrode main body 11 configured as described above is inserted into the mounting hole 37 formed in the intermediate electrode holder 7 by pressing and fixing the bush 15 from the lower surface side of the intermediate electrode holder 7 to the tip portion. It is supported by the side of the intermediate electrode holder 7 by being slidably inserted in the axial direction with 11b facing upward. In this supporting state, the stopper 17 provided near the end of the body portion 11a prevents the stopper 11 from coming out downward, and the spring disposed between the bush 15 and the shoulder portion 11d is compressed. It is always urged downward by 18. Therefore, the electrode body 11 is at the lowermost position where the stopper 17 and the bush 15 are engaged (in the following description, in this case, in the state where no external force acts in the axial direction (state of FIG. 3)). The electrode body 11, that is, the position of the intermediate electrode 10 is located at the retracted position. On the other hand, when an upward pressing force is applied to the electrode contact surface 11f via the first electrode 1, the electrode body 11 causes the spring 18 to be contracted and displaced to move upward ( Hereinafter, the highest position of the electrode body 11 will be referred to as the forward position.

Further, between the electrode body 11 and the bush 15 is to regulate the relative rotation between the electrode body 11 and the bush 15 (that is, the relative rotation between the electrode body 11 and the intermediate electrode holder 7). The key 16 is provided so that the relative position of the electrode body 11 in the rotational direction with respect to the bush 15 is always kept constant regardless of the forward / backward displacement of the electrode body 11.

The tip 12 is integrally formed of a circular cap body made of copper, and its top surface is a work contact surface 12a. The work contact surface 12a has a shape that matches the surface shape of the work 3 to which the work contact surface 12a corresponds. In this embodiment, as shown in FIG. 1, since the work 3 is a curved surface having a large radius of curvature, the work contact surface 12a is also a curved surface along the surface shape of the work 3. There is. Then, in that case, the projection area of the work contact surface 12a onto the surface orthogonal to the chip axis is large enough to cover one welding point of the work 3 (specifically, the work 3 has The size is set so as to cover the formed nugget portion and a predetermined range outside thereof.

Further, the inner peripheral side of the tip 12 is formed as a tapered hole 12b having a tapered surface which can be closely fitted to the tip portion 11b of the electrode body 11, and the tip 12 has the tapered hole 12b. Is integrated with the side of the electrode body 11 by press-fitting it to the tip portion 11b of the electrode body 11, and a space 24 having a predetermined size is formed between the electrode body 11 and the tip surface 11e. Here, when the tip 12 is fitted and fixed to the tip portion 11b of the electrode body 11, the surface shape of the work contact surface 12a of the tip 12 matches the surface shape of the corresponding portion of the work 3. As described above, the relative position in the circumferential direction is strictly set. Therefore, as described above, since the electrode body 11 is supported in a state in which the relative rotation of the electrode body 11 is regulated with respect to the intermediate electrode holder 7, the relative position between the intermediate electrode holder 7 and the work 3 is accurate. In the set state, proper correspondence between the work contact surface 12a and the work 3 is always ensured.

By the way, in this embodiment, the five intermediate electrodes 10, 10, ... Having the above-mentioned structure are arranged in parallel on the intermediate electrode holder 7 along the welding point on the work 3 side. However, in that case, the work contact surfaces 12a of the tips 12 of the respective intermediate electrodes 10, 10, ... Are, of course, set such that their surface shapes match the surface shapes of the corresponding portions of the work 3, respectively. In particular, in this embodiment, as shown in FIG. 1, in the set state of the work 3, the work 3 and the work contact surfaces 12a, 12a, ... Of the respective intermediate electrodes 10, 10 ,. The length dimension of the tip portion 11b of the electrode body 11 is adjusted so that the intervals are substantially constant. Therefore, in another embodiment of the present invention, this interval adjustment may be performed by adjusting the axial length of the tip 12, or without adjusting the interval, the respective intermediate electrodes 10, 10 ,. It is also possible to set the dimension to be constant and to make the intervals between the work contact surfaces 12a, 12a and the work 3 sequentially different.

Next, as an example, the spot welding apparatus Z configured as described above is used to perform spot welding on the work 3 formed by stacking two members to be joined 4 and 5. The procedure in that case will be explained. First, the relative positions of the above-mentioned support frame 6 fixed to the floor surface and the intermediate electrode holder 7 are adjusted, and each of them is attached to the intermediate electrode holder 7. The relative positions of the intermediate electrodes 10, 10, ..., And the respective welding points of the work 3 corresponding thereto in the vertical direction and in the plane direction are accurately determined.

Next, the first electrode 1 and the second electrode 2 are respectively retracted, and a predetermined size is provided between the second electrode 2 and each of the intermediate electrodes 10, 10, ... (ie, the intermediate electrode assembly 9). In the state where the work setting space is formed, the work 3 is placed in the setting space and is fixed to the setting table (not shown). This completes the preparation work. Since a relatively large space for setting is provided during the work of setting the work 3, the work 3 may be damaged due to the interference between the work 3 and the intermediate electrode 10 or the second electrode 2. It is possible to prevent this, and in particular, the yield of the products is improved because no damage is generated on the surface on the side of the intermediate electrode 10 where welding marks are disliked.

Next, using the first electrode 1 and the second electrode 2, spot welding is sequentially performed on each welding spot. That is, as shown by the chain line in FIG. 1, for example, when spot welding is first performed on the center welding spot of the five welding spots, the position of the intermediate electrode 10 at the center of the intermediate electrode assembly 9 is described. The first electrode 1 and the second electrode 2 are moved to, and then the first electrode 1 and the second electrode 2 are moved in the approaching directions. In this case, the second electrode 2 is brought into close contact with the member to be joined 4 on the upper surface side of the work 3 and is directly brought into contact therewith, but in the member to be joined 5 on the lower side, first the first electrode 1 Moves to the side of the intermediate electrode 10 and contacts the electrode contact surface 11f, and by pushing up the intermediate electrode 10 as it is, the intermediate electrode 10 moves to the side of the member 5 to be bonded and the chip 12 contacts the workpiece. The surface 12a is brought into contact with the member 5 to be joined. Then, after the second electrode 2 and the intermediate electrode 10 both come into contact with the joined member 4 and the joined member 5 of the work 3, a predetermined pressing force is applied between the electrodes 1 and 2 to cause the work. 3 is sandwiched between the second electrode 2 and the intermediate electrode 10, and a predetermined voltage is applied between the electrodes 1 and 2.

By applying the voltage between the electrodes 1 and 2, a current flows between the electrodes 1 and 2 through the work 3 and the intermediate electrode 10, and the contact resistance is the largest in the conductive path. Resistance heat is generated at the contact portion between the members 4 and 5 to be joined of the work 3, and the portion is melted to perform the joining. In this case, on the bonded member 4 side, the second electrode 2 directly abuts and a large pressing force is applied to the molten portion, so that a welding mark is generated. However, since the work contact surface 12a of the chip 12 has a larger area than the melting range of the work 3 (that is, the cross-sectional area of the nugget) on the side of the member 5 to be bonded, The pressing force is supported not in the melted portion but in the non-melted portion on the outside thereof, so that the generation of welding marks is prevented. That is, it is possible to obtain a welded product having no welding mark on one surface.

When the predetermined energization time has passed and the welding is completed, the electrodes 1 and 2 are retreated to prepare for welding to the next welding point. The retraction of the electrodes 1 and 2 causes the above intermediate electrode 10 to move. Since the external force against this disappears, the spring force of the spring 18 causes the spring 18 to automatically return to the retracted position from the forward position, and a space for setting is provided between the second electrode 2 which has already retracted and the intermediate electrode 10. Form again.

By sequentially performing the welding operation with the pair of electrodes 1 and 2 as described above on the remaining four welding points (that is, the portions corresponding to the remaining four intermediate electrodes 10, 10, ...), Spot welding is applied to all three welding points. When the welding to all welding points is completed, the work 3 is removed from the set table. In this case, the second electrode 2 and the intermediate electrode 10 are automatically moved as the electrodes 1 and 2 retreat as described above. Since a space for setting is formed between and, the work piece 3 can be removed without contacting the second electrode 2 or the intermediate electrode 10 (that is, without causing damage due to interference). The quality of the product is maintained good and the product yield is improved.

By the way, when spot welding is performed at each welding spot as described above, since the intermediate electrodes 10, 10, ... Are not rotated with respect to the intermediate electrode holder 7, Welding is ensured in the state where the work 3 and the work contact surface 12a of the intermediate electrode 10 are in close contact with each other at each welding point, which results in a highly accurate and well formed nugget, and a welded product with high strength reliability. Is what you can get.

Further, the wear of any one of the intermediate electrodes 10, 10, ... Is greater than that of the other ones due to long-term use, and the contact state between the work contact surface 12a and the work 3 is deteriorated. However, when the reliability of the welding spot by the intermediate electrode 10 is impaired, it is necessary to restore the close contact state of the intermediate electrode 10 with the work 3. In this case, in the case of the present embodiment, only the intermediate electrode 10 in which the inconvenience has occurred, and the tip 12 is replaced with a new one, or the tip 12 is reworked, so that the other intermediate electrodes It is possible to improve the performance of the intermediate electrode assembly 9 as a whole without any modification to the electrodes 10, 10. Therefore, for example, as in the case of spot welding using a thick plate-shaped intermediate electrode as in the conventional case, when any one of the multiple welding points covered by the intermediate electrode is inconvenient. However, maintenance of the intermediate electrodes 10, 10, ... Is easier and requires less maintenance man-hours compared to the one in which the intermediate electrode must be reworked as a whole, which lowers the maintenance cost. However, the operating cost of the spot welding apparatus as a whole can be reduced.

Further, as described above, when the intermediate electrodes 10, 10, ... Are sequentially used to perform spot welding at the welding points corresponding to these intermediate electrodes 10, 10 ,. Cooling water is supplied to the cooling water outlet pipe 22 side from the vacant chamber 24 through the cooling water passage 23. By thus introducing the cooling water into the vacant chamber 24 on the back side of the chip 12, the temperature rise of the chip 12 is effectively prevented, and the wear of the chip 12 due to heat damage is prevented as much as possible. The durability of the tip 12 is improved, and the operating frequency of the spot welding apparatus can be reduced by reducing the replacement frequency of the chip 12.

Further, since the respective intermediate electrodes 10, 10, ... Of the intermediate electrode assembly 9 are arranged corresponding to the respective welding points of the work 3, for example, a conventional thick plate-shaped intermediate electrode is used. There is no need to mark welding spots on the intermediate electrode prior to work as with spot welding equipment.Since the work can be simplified and workability improved, the welding spots can be accurately processed. Since welding can be performed, work reliability is improved, and such an advantage is particularly remarkable in manual welding.

[Brief description of drawings]

FIG. 1 is a front view of a main portion of a spot welding apparatus according to an embodiment of the present invention.

FIG. 2 is a view taken along the line II-II in FIG.

3 is a sectional view taken along line III-III in FIG.

4 is a view taken along the line IV-IV in FIG.

[Explanation of symbols]

Reference numeral 1 is a first electrode, 2 is a second electrode, 3 is a work, 4 and 5 are members to be joined, 6 is a supporting frame, 7 is an intermediate electrode holder, 8 is a fixing bolt, 9 is an intermediate electrode assembly, and 10 is an intermediate electrode. , 11 is an electrode body, 11f is an electrode contact surface, 12
Is a tip, 12a is a work contact surface, 15 is a bush, 1
6 is a key, 17 is a stopper, 18 is a spring, 21
Is a cooling water inlet pipe, 22 is a cooling water outlet pipe, 23 is a cooling water passage, 24 is an empty chamber, and 37 is a mounting hole.

Claims (3)

[Scope of utility model registration request] 1. A pair of electrodes are arranged to face each other so as to be able to come in contact with and separate from each other in a direction in which a work is sandwiched in the plate thickness direction, and any one electrode of the pair of electrodes directly abuts the work. The other electrode is a spot welding apparatus in which the electrode is brought into contact with the work through the intermediate electrode, and the intermediate electrode has an area whose tip surface can cover a single welding point. It is a work contact surface, and its rear end surface is an electrode contact surface, and it is supported by a support member so as to be movable in the direction of contacting with and separating from the work and non-rotating about the movement axis. Characteristic spot welding equipment. 2. The electrode body according to claim 1, wherein the intermediate electrode is detachably attached to an electrode main body supported by the support member, and the tip end surface of the electrode main body is the work contact surface. A spot welding device characterized by being configured with a tip. 3. The intermediate electrode according to claim 1, wherein a plurality of the intermediate electrodes are attached to the support member, and the surface shapes of the workpiece contact surfaces of the plurality of intermediate electrodes are the intermediate shapes of the workpiece. The spot welding apparatus is characterized in that the electrodes are made to match the surface shapes of the corresponding portions, respectively.