JP3123346B2 - Auxiliary electrode for resistance welding and resistance welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary electrode for resistance welding and a resistance welding method used for performing resistance welding.

[0002]

2. Description of the Related Art Conventionally, as an auxiliary electrode for resistance welding as described above, for example, there is one shown in FIG.

The auxiliary electrode 51 for resistance welding shown in FIG. 1 is mounted horizontally on a post 53 erected on a base 52, and is located between a pair of a tip t1 on the workpiece and a tip t2 on the back electrode. A bracket 54 and a welding surface 55a rotatably fitted into a through hole 54a provided in the back electrode bracket 54 and facing the workpieces w1 and w2, and a chip abutment parallel to the welding surface 55a. A cylindrical back electrode 55 having a surface 55b is provided.

A groove 55 is provided at an intermediate portion of the cylindrical back electrode 55.
c is provided, and the cylindrical back electrode 55
The stopper 56 provided on the lower surface of the back electrode bracket 54 protruding into the inside of the back electrode bracket 54 prevents the back electrode bracket 54 from dropping off the back electrode bracket 54. The difference between the groove width of the groove 55c and the thickness of the stopper 56 is s. It is movable in the rotation axis direction with respect to the back electrode bracket 54.

[0005] When resistance welding is performed on the materials to be welded w1 and w2 having bent portions using the auxiliary electrode 51 for resistance welding, first, the flat surface placed on the back electrode bracket 54 is used. At the hit point position p1 on the flat surface side inclined at an angle θ1 with respect to the workpiece to be welded w1, w2, that is, on the tip axis tl inclined by an angle θ1 with respect to the vertical axis, the workpiece side tip t1 And the tip t2 on the back electrode side, respectively,
In step 1, resistance welding is performed.

Next, at the hitting position p2 on the flat surface side on the back electrode bracket 54, the materials to be welded w1, w2 are formed by the material to be welded tip t1 and the back electrode side tip t2 whose tip axis tl is inclined as described above. And the cylindrical back electrode 55, and the back electrode side tip t
2, the cylindrical back electrode 55 is pressed and slid along the through hole 54a of the back electrode bracket 54, and welding is performed by bringing the welding surface 55a into contact with the workpiece w1.

The auxiliary electrode 51 for resistance welding is formed by
No.-17756.

[0008]

However, in the conventional auxiliary electrode 51 for resistance welding, the angle .theta.
The resistance welding can be performed on the workpieces w1 and w2 bent in the above manner at any of the hitting positions p1 and p2 inclined with respect to each other, but the flat surface is always mounted on the back electrode bracket 54. In many cases, resistance welding cannot be performed on workpieces with deep drawn shapes or irregularities, for example, resistance welding must be performed on these workpieces. However, there is a problem that dents and deformations are likely to occur in the welded portion even if it is formed.

When performing resistance welding using the auxiliary electrode 51 for resistance welding, the tip axis tl connecting the tip t1 on the workpiece to be welded and the tip t2 on the back electrode is not inclined by an angle θ1 with respect to the vertical axis. Therefore, the tip axis tl is not orthogonal to the flat surfaces of the workpieces w1 and w2 at the hitting point p2 on the back electrode bracket 54. As a result, a loss occurs in the pressing force by the cylindrical back electrode 55. In addition, there is a possibility that the welding strength may be reduced, and in addition, there is a problem that the welded material side tip t1, the back electrode side tip t2, and the cylindrical back electrode 55 are apt to be unevenly worn. Was an issue.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and the invention according to claims 1 to 3 does not allow resistance welding to be performed on a flat workpiece. Needless to say, resistance welding is performed without causing dents or deformation in the welded part, even for deep drawing shapes or uneven materials that cannot place a flat surface on the back electrode bracket. It is intended to provide a resistance welding auxiliary electrode capable of performing
An object of the invention according to claim 4 is to provide a resistance welding method capable of improving welding strength and preventing uneven wear of the tip and the cylindrical back electrode.

[0011]

According to a first aspect of the present invention, there is provided a back electrode bracket provided substantially horizontally between a pair of welding tips and a substantially vertical through hole in the back electrode bracket. Auxiliary electrode for resistance welding provided with a cylindrical back electrode that is freely and movably held in the rotation axis direction and has a welding surface that abuts the lower surface of the material to be welded and a chip abutting surface that is parallel to the welding surface. At
It is characterized in that the rotation axis of the cylindrical back electrode can be inclined with respect to the center line of the through hole in the back electrode bracket, and this configuration of the auxiliary electrode for resistance welding solves the above-mentioned conventional problems. Means.

According to a second aspect of the present invention, a clearance is provided between a cylindrical back electrode and a through-hole, and a rotation axis of the cylindrical back electrode is aligned with a center line of the through-hole in the back electrode bracket. The invention according to claim 3 of the present invention is directed to a tip side having a welding surface and having a cylindrical portion having a welded material side and a diameter larger than a through hole of a back electrode bracket and a tip contact surface. Forming a cylindrical back electrode from the cylindrical portion and the through-hole insertion portion provided between the two cylindrical portions,
The cylindrical portion of the cylindrical back electrode on the material to be welded is placed on the back electrode bracket, and the through-hole insertion portion is inserted into the through-hole with a clearance.

The invention according to claim 4 of the present invention provides:
When performing resistance welding using the auxiliary electrode for resistance welding according to any one of claims 1 to 3, the tip of the welded material side tip and the cylindrical back electrode sandwiching the welded material together with the welding surface of the cylindrical back electrode. The resistance welding is performed by offsetting the tip axis connecting the tip on the back electrode side contacting the tip contact surface with the center line of the through hole in the back electrode bracket. The configuration of the method is a means for solving the above-mentioned conventional problem.

[0014]

In the auxiliary electrode for resistance welding according to the first and second aspects of the present invention, the material to be welded is set on the back electrode bracket, and the material to be welded and the cylindrical back electrode are sandwiched by a pair of welding tips. Then, the cylindrical back electrode is pressed by the tip on the back electrode side and moves to the material to be welded along the through hole of the back electrode bracket, and when the welding surface of the cylindrical back electrode comes into contact with the material to be welded, the resistance is reduced. Welding will be performed.

During this time, when the material to be welded is not parallel to the back electrode bracket, in addition to rotating the columnar back electrode around the rotation axis, the rotation axis is rotated by the through hole in the back electrode bracket. Since the welding surface of the cylindrical back electrode follows the welding surface of the material to be welded by tilting with respect to the center line of the material to be welded, even if the material to be welded has a deep drawn shape, Any part of the welding surface of the cylindrical back electrode comes into contact directly behind the point where the tip on the side comes into contact with the material to be welded, and as a result, resistance welding is reliably performed at this point. .

Also, when the cylindrical back electrode is pressed by the tip on the back electrode side and moves toward the material to be welded along the through hole of the back electrode bracket, the cylindrical back electrode floats with respect to the back electrode bracket. Therefore, the weight of the cylindrical back electrode is always applied to the tip on the back electrode side, and even if the material to be welded has a deep drawing shape as described above, the tip on the material to be welded and the material to be welded The welding surface of the cylindrical back electrode abuts directly behind the hitting position where it abuts without uneven contact. In particular, in the auxiliary electrode for resistance welding according to claim 3, the cylindrical portion of the cylindrical back electrode on the material to be welded. Is mounted on the back electrode bracket, so that it is not necessary to use a stopper which has been used conventionally.

Further, in the resistance welding method according to the fourth aspect, when performing resistance welding using the auxiliary electrode for resistance welding according to any one of the first to third aspects, the tip on the side of the material to be welded is used. Since the tip axis connecting the tip of the back electrode that contacts the tip contact surface of the cylindrical back electrode is offset parallel to the center line of the through hole in the back electrode bracket, the pressure applied by the cylindrical back electrode is reduced. Loss is reduced to improve welding strength, and the cylindrical back electrode is easily rotated in the through hole of the back electrode bracket, so that uneven wear of the tip and the cylindrical back electrode is reduced.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an embodiment of an auxiliary electrode for resistance welding and a resistance welding method according to the present invention.

As shown in FIG. 1, the auxiliary electrode 1 for resistance welding includes a back electrode bracket 10 attached to a post gauge 3 erected on a base 2, and a cylindrical back electrode held by the back electrode bracket 10. 20.

The back electrode bracket 10 includes a hook-shaped bracket 11 fixed to the post gauge 3 and a flat bracket 12 fixed to a horizontal portion of the hook-shaped bracket 11 by bolts (not shown). A through hole 13 is provided in the flat bracket portion 12 in the vertical direction, and the flat bracket portion 1 is provided between the pair of the tip T1 on the workpiece and the tip T2 on the back electrode.
The portion of the through hole 13 in 2 is positioned.

The cylindrical back electrode 20 is made of a material to be welded W1, W
The welded material-side cylindrical portion 22 having a welding surface 21 facing the second side and having a diameter larger than the through hole 13 of the back electrode bracket 10.
And a tip-side cylindrical portion 24 having a tip contact surface 23 parallel to the welding surface 21 and having substantially the same diameter as the welded-material-side cylindrical portion 22, and a through hole provided between the two cylindrical portions 22, 24. By inserting the to-be-welded-side cylindrical portion 22 on the flat bracket portion 12 of the back electrode bracket 10 and inserting the through-hole insertion portion 25 into the through-hole 13,
It is held by the back electrode bracket 10.

In this case, a vertical clearance S is set between the chip-side cylindrical portion 24 and the flat bracket portion 12 of the back electrode bracket 10, and a clearance between the through-hole insertion portion 25 and the through-hole 13 is formed. Horizontal clearances U and V are set between the cylindrical back electrodes 20.
Is a back electrode bracket 1 as shown in FIG.
0 and can be moved in the direction of the rotation axis L of the through hole 13 and the rotation axis L can be inclined with respect to the center line CL of the through hole 13. Can be tilted with respect to.

When resistance welding is performed on the curved portions (not shown in FIG. 1) of the workpieces W1 and W2 using the resistance welding auxiliary electrode 1, first, FIG.
As shown in (a), the back electrode bracket 10 is set so that the curved portions of the workpieces W1 and W2 are located in the through holes 13 of the back electrode bracket 10.

Next, the tip axis TL connecting the pair of the welded material side tip T1 and the back electrode side tip T2 is defined by the center line C of the through hole 13 in the back electrode bracket 10.
After being offset parallel to L by a distance D, the workpiece T1, the back electrode T2 and the workpiece W1, W2 and the cylindrical back electrode 2
2, the cylindrical back electrode 20 is pressed by the back electrode side tip T <b> 2 and along the through-hole 13 of the back electrode bracket 10, as shown in FIG.
1, W2 side, and the welding surface 21 of the cylindrical back electrode 20
The resistance welding is performed at the time when the steel is pressed against the striking position P of the material to be welded W2 used as the outer plate that emphasizes the appearance.

At this time, the cylindrical back electrode 20 is rotated
In addition to pivoting around, the vertical axis S and the horizontal clearances U and V are used to make this pivot axis L itself through-hole 1 in the back electrode bracket 10.
3 is tilted with respect to the center line CL of FIG. 3 and the posture of the cylindrical back electrode 20 is tilted.
Follows the curved portion of the material to be welded W2, and any one of the welding surfaces 21 of the cylindrical back electrode 20 is attached to the material to be welded W2 directly behind the hitting point P where the material to be welded tip T1 and the material to be welded W1 abut. These portions come into contact with each other, so that the resistance welding is performed reliably at this hitting point position P without causing a dent or deformation in the welded portion.

When the cylindrical back electrode 20 is pressed by the back electrode side tip T2 and moves toward the workpiece W2 along the through hole 13 of the back electrode bracket 10, the cylindrical back electrode 20 is Therefore, the weight of the cylindrical back electrode 20 is always applied to the tip T2 on the back electrode side, and the welding surface 21 of the cylindrical back electrode 20 abuts on the workpiece W2 without hitting one side. In addition, since the welded material-side cylindrical portion 22 having the welding surface 21 has a larger diameter than the through hole 13 of the back electrode bracket 10, it is not necessary to use a stopper for preventing the cylindrical back electrode from dropping. Becomes

Further, the tip axis TL connecting the workpiece-side tip T1 and the back electrode-side tip T2 is offset parallel to the center line CL of the through hole 13 in the back electrode bracket 10 by a distance D. Loss of the pressing force due to the cylindrical back electrode 20 is almost eliminated, so that the welding strength is improved. In addition, the cylindrical back electrode 20 is easily rotated in the through hole 13 of the back electrode bracket 10, and the back electrode side tip T2 and the column Uneven wear of the back electrode 20 is also reduced.

The detailed constructions of the auxiliary electrode for resistance welding and the resistance welding method according to the present invention are not limited to the above-described embodiment.

[0030]

As described above, according to the first aspect of the present invention,
In the auxiliary electrode for resistance welding according to claim 2, since the above-described configuration is employed, when performing resistance welding by sandwiching the material to be welded and the cylindrical back electrode with a pair of welding tips, the cylindrical back electrode is attached to the back electrode side tip. When pressed and moved to the material to be welded along the through hole of the back electrode bracket, the cylindrical back electrode rotates around the rotation axis, and in addition, the cylindrical back electrode itself is inserted into the through hole of the back electrode bracket. The welding surface of the cylindrical back electrode can follow the welding surface of the material to be welded, and as a result, not only flat materials but also deep drawn shapes and materials with irregularities However, resistance welding can be performed without causing dents or deformation,
In addition, when the cylindrical back electrode moves along the through hole, the cylindrical back electrode can be floated with respect to the back electrode bracket, so that the weight of the cylindrical back electrode is always applied to the back electrode side chip. It is possible, as described above, even if the material to be welded has a deep drawing shape, the welding surface of the cylindrical back electrode is located directly behind the hit point where the material to be welded and the material to be welded come into contact with each other. The contact can be made without causing a bias.
In the resistance welding auxiliary electrode according to the above, since the welded material side cylindrical portion of the cylindrical back electrode is mounted on the back electrode bracket, it is possible to eliminate the need for a stopper for drop prevention, which is an extremely excellent effect. Is brought.

Further, in the resistance welding method according to claim 4 of the present invention, when performing resistance welding using the auxiliary electrode for resistance welding according to any one of claims 1 to 3, the material to be welded is used. Since the chip axis connecting the side tip and the back electrode side tip is offset parallel to the center line of the through hole of the back electrode bracket, the loss of the pressing force due to the cylindrical back electrode can be reduced, Rotation of the cylindrical back electrode in the through hole of the back electrode bracket can be performed smoothly,
As a result, it is possible to achieve an extremely excellent effect that the welding strength can be improved and the uneven wear of the tip and the cylindrical back electrode can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory front view of an auxiliary electrode for resistance welding showing one embodiment of an auxiliary electrode for resistance welding and a resistance welding method according to the present invention.

FIG. 2 (a) is a partial cross-sectional explanatory view showing a state where a material to be welded is set on an auxiliary electrode for resistance welding shown in FIG. 1; (B)
FIG. 3 is a partial cross-sectional explanatory view showing a state where resistance welding is being performed on a material to be welded set on an auxiliary electrode for resistance welding in FIG.

FIG. 3 is an explanatory front view showing a conventional resistance welding auxiliary electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Auxiliary electrode for resistance welding 10 Back electrode bracket 13 Through hole 20 Cylindrical back electrode 21 Welding surface 22 Column portion to be welded 23 Chip contact surface 24 Chip side middle portion 25 Through hole insertion portion CL Center line of through hole L Column Rotation axis of back electrode S Vertical clearance TL Tip axis T1 Tip of workpiece to be welded T2 Tip of back electrode U, V Horizontal clearance W1, W2 Workpiece to be welded

Continuation of the front page (56) References Japanese Utility Model Sho 60-84190 (JP, U) Japanese Utility Model Sho 62-179184 (JP, U) Japanese Utility Model Sho 57-15032 (JP, Y2) Japanese Patent Publication No. 39-1330 (JP) , B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 11/30 B23K 11/11

Claims (4)

(57) [Claims] 1. A back electrode bracket provided substantially horizontally between a pair of welding tips, and held in a substantially vertical through hole in the back electrode bracket so as to be rotatable and movable in a rotating axis direction. In a resistance welding auxiliary electrode including a cylindrical back electrode having a welding surface in contact with a lower surface of a material to be welded and a chip abutting surface parallel to the welding surface, the rotation axis of the cylindrical back electrode is passed through the back electrode bracket. An auxiliary electrode for resistance welding, characterized in that the auxiliary electrode can be inclined with respect to the center line of the hole. 2. The back electrode bracket according to claim 1, wherein a clearance is provided between the cylindrical back electrode and the through hole so that a rotation axis of the cylindrical back electrode can be inclined with respect to a center line of the through hole in the back electrode bracket. Auxiliary electrode for resistance welding. 3. A through hole provided between the two cylindrical portions and a tip side cylindrical portion having a welding surface and a diameter larger than the through hole of the back electrode bracket and having a tip contact surface. The cylindrical back electrode is configured from the first and second portions, and the welded material-side cylindrical portion of the cylindrical back electrode is placed on the back electrode bracket, and the through-hole insertion portion is inserted into the through-hole with a clearance. Auxiliary electrode for resistance welding. 4. A welding material side tip for sandwiching a welding material together with a welding surface of a cylindrical back electrode when performing resistance welding using the resistance welding auxiliary electrode according to any one of claims 1 to 3. Resistance welding is performed by offsetting a tip axis connecting a back electrode side tip that abuts on a tip contact surface of the cylindrical back electrode to be parallel to a center line of a through hole in the back electrode bracket. Method.