JP2822818B2 - 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, and more particularly to a spot welding apparatus in which a pair of stud type spot welding guns individually supported by a welding robot are opposed to each other to perform welding.

[0002]

2. Description of the Related Art As a spot welding apparatus mainly constituted by a stud type spot welding gun, there is one having a structure shown in FIG. In this conventional spot welding apparatus, upper and lower stud type spot welding guns 1 and 2 are mounted on wrist portions 7 and 8 at the tips of arms 5 and 6 of independent welding robots 3 and 4, respectively. Positioning jigs 9 and 10 for work (weld) W to be welded
And the upper and lower spot welding guns 1 and 2 are moved to a predetermined welding position by the movement of the welding robots 3 and 4 so that they face each other. Each of the electrodes (tips) 11 and 12 is extended by extending the pressurized cylinder thus set.
However, spot welding is performed by clamping the work W under pressure.

When spot welding is performed on several types of workpieces at random, the positioning jigs 9 and 10 are moved to welding positions according to the type of each workpiece W and the positions are switched.

[0004]

However, in the conventional spot welding apparatus as described above, a predetermined position corresponding to the type of the work W is positioned and clamped by the positioning jigs 9, 10. Similarly, since the spot welding guns 1 and 2 are moved to welding positions predetermined according to the type of the work W to perform welding, the work W by the positioning jigs 9 and 10 is performed.
In the case of the positioning error described above, the final hitting position at which spot welding is to be performed by the electrodes 11 and 12 depends on the balance between the pressing forces of the upper and lower spot welding guns 1 and 2 which compete with each other. Therefore, both electrodes 1
When the workpiece W is pressed and held between the workpieces 1 and 12, the workpiece W
However, there is a problem that the accuracy of the hitting position varies and the stabilization is not stabilized.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. Particularly, it is possible to prevent the deformation of a work when the work is pressed and clamped by a pair of spot welding guns, and to improve the accuracy of the hitting position. It is intended to provide an intended structure.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a pair of stud type spot welding guns individually supported on an arm of a welding robot are opposed to each other, and an object to be welded is applied by electrodes of the pair of spot welding guns. In a device for performing spot welding by clamping, apart from a positioning jig for positioning and clamping a workpiece to be welded, when the spot welding guns face each other, they face each other, A positioning gauge for pressing and holding the vicinity of the hitting point of the electrode of the workpiece based on the movement of the welding robot together with the spot welding gun is individually supported on the arm of each welding robot. Then, each of the electrodes comes into contact with the workpiece to be welded.
While the pressure is increasing, the workpiece is
After welding, each electrode exerts a force on the workpiece after welding.
Release the pressure of the positioning gauge while the pressure is released
It is set to do.

[0007]

According to this structure, when a pair of spot welding guns are moved to the welding position by the movement of the welding robot, the two spot welding guns are opposed to each other and simultaneously with each spot welding gun. The provided positioning gauges are also opposed to each other, and the positioning gauges pressurize and restrict the peripheral portion of the workpiece to be welded with the spot welding gun at the point where the spot should be welded. At this time, each of the electrodes comes into contact with the workpiece and pressurizes it.
Pressurizes the work piece with the positioning gauge while the force rises
I do.

[0008] Thus, the final hitting position to be welded by the pair of spot welding guns does not depend on the positioning accuracy of the positioning jig for positioning and clamping the workpiece to be welded. Is determined by the pressure constraint force of the positioning gauge, the position accuracy of the hitting position is stabilized regardless of the position of the welding regardless of the type of the workpiece. At the same time, a pair of electrodes
In the process of contacting the weldment and increasing the pressure,
The pressing force by the setting gauge can be obtained instantaneously.
Before welding, the workpiece is deformed by the pressure of the electrode.
Such a situation can be avoided.

[0009]

1 and 2 show an embodiment of the present invention, in which portions common to those of the prior art shown in FIG. 4 are denoted by the same reference numerals.

As shown in FIGS. 1 and 2, the wrists 7, 8 at the tips of the arms 5, 6 of the welding robots 3, 4 are provided with positioning gauges 13, 14 together with stud type spot welding guns 1, 2. They are individually juxtaposed. The positioning gauges 13, 14 are formed by integrally forming ring-shaped pressing plates 17, 18 at the ends of stays 15, 16 connected to the wrist portions 7, 8. Relief holes 19 and 20 correspond to the positions of the electrodes 11 and 12 of the corresponding spot welding guns 1 and 2 so that the work (workpiece) W is pressed and held by both spot welding guns 1 and 2. Each electrode 11,
The interference between 12 and the holding plates 17 and 18 is avoided.

The positioning gauges 13, 14
When the spot welding guns 1 and 2 are positioned at predetermined welding positions by the movements of the welding robots 3 and 4, the pair of positioning gauges 13 and 14 face each other with the work W interposed therebetween. The length and the like are set in advance so that the work W is pressed from both the front and back surfaces with a predetermined pressure.

Further, the pair of positioning gauges 13, 1
As shown in FIG. 3, the pressure of the work W by the positioning gauge 1 is determined while the electrodes 11 and 12 of the spot welding guns 1 and 2 are in contact with the work W to obtain the pressing force.
3 and 14 start pressurizing, and after welding, each electrode 1
Positioning gauge 1 during the release of pressures 1 and 12
It is set so that the pressing forces of 3, 14 are released.

The delicate timing lag at the time of pressurizing the electrodes 11 and 12 and the positioning gauges 13 and 14 or at the time of releasing the pressurizing force is caused by the timing at which the welding robots 3 and 4 start to move and the spot welding guns 1 and 2. It can be realized by adjusting the operation timing of the pressurizing cylinder built in the.

In the spot welding apparatus configured as described above, when the work W is positioned and clamped by the positioning jigs 9 and 10, the welding robots 3 and 4 are set in advance, as in the prior art. The spot welding guns 1 and 2 are moved to a predetermined welding position along the locus to position each spot welding gun 1 and 2.

When the upper and lower spot welding guns 1 and 2 are positioned in this manner, the two spot welding guns 1 and 2 face each other with the work W interposed therebetween. The work W is pressed and clamped by the electrodes 11 and 12 of the spot welding guns 1 and 2 by extending the pressurizing cylinder built therein. Then, after the pressurizing operation of the work W by the two electrodes 11 and 12, energization is performed by a normal method to perform spot welding.

At this time, as described above with reference to FIG. 3, the electrodes 11 and 12 are set in contact with the workpiece W by the extension operation of the pressurizing cylinders built in the spot welding guns 1 and 2. Until the pressing force is reached, both the positioning gauges 13 and 14 face each other and the electrode 1 of the work W
The periphery of the portion corresponding to 1 and 12 is pressed and clamped.

Therefore, even if the pressing force of each of the electrodes 11 and 12 reaches the set pressing force and the spot welding is performed by energization, the positional accuracy of the final hitting position is determined by the positioning jigs 9 and 10. Since it is determined by the pressing position by the two positioning gauges 13 and 14 without depending on the positioning accuracy of the workpiece W, the spot position is not varied even if spot welding is performed at any position. Position accuracy is stabilized.

Moreover, as described above, both electrodes 1
Since the pressing force of the pair of positioning gauges 13 and 14 is instantaneously obtained in a process where the pressing force increases due to the contact of the workpieces 1 and 12 with the workpiece W, the welding force of the electrodes 11 and 12 is applied to the workpiece W before welding. Will not be deformed. Similarly, when the pair of electrodes 11 and 12 release the work W after welding, the pressing force by the positioning gauges 13 and 14 is instantaneously released while the pressing force by the electrodes 11 and 12 is released. Therefore, the work W is not deformed by the electrodes 11 and 12.

[0019]

As described above, according to the present invention, apart from the positioning jig for positioning and clamping the work to be welded, the vicinity of the position of the stud type spot welding gun of the work to be welded is determined by the welding robot. Positioning gauges that press and clamp based on the movement are individually supported on a pair of welding robot arms together with the spot welding gun. It is determined by the pressing force of the pair of positioning gauges without depending on the positioning accuracy of the object. Therefore, unlike the related art, the workpiece is not deformed by the pressing force of the electrode of the spot welding gun, and the positional accuracy of the hitting position by the electrode is eliminated, thereby improving the accuracy of the hitting position.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of a main part showing one embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a timing chart showing pressurization timing by the electrodes and the positioning gauge shown in FIG. 1;

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

[Explanation of symbols]

 1,2 ... Spot welding gun 3,4 ... Welding robot 5,6 ... Arm 7,8 ... Wrist part 9,10 ... Positioning jig 11,12 ... Electrode 13,14 ... Positioning gauge W ... Work (workpiece)

Claims (1)

(57) [Claims] 1. A pair of stud type spot welding guns individually supported on an arm of a welding robot are opposed to each other, and spot welding is performed by clamping an object to be welded by electrodes of the pair of spot welding guns. In the apparatus as described above, apart from a positioning jig for positioning and clamping a workpiece to be welded, when the spot welding guns face each other, the spot welding guns are opposed to each other, and an electrode of the workpiece is formed by an electrode. positioning gauge pressure圧挾lifting based near strike position to the movement of the welding robot, are supported separately on the arms of the welding robot with the spot welding gun, the pressurizing force each electrode is in contact with the object to be welded Rise
While the work piece is pressurized by the positioning gauge on the way,
After contact, the pressure applied to each workpiece by the electrodes is released.
To release the pressure of the positioning gauge during
Spot welding apparatus, characterized in that the.