JPS6116238B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spot welding method, and more particularly to an automatic spot welding method for automatically performing multi-point welding using a welding robot.

Spot welding of a workpiece having a large number of welding points, such as the body of an automobile, is often automatically performed using a welding robot that indexes a welding gun according to a predetermined schedule. Since spot welding in such an automatic welding line is one-gun, multi-point welding, the tip of the electrode tip is subject to severe wear and damage due to irregular plastic deformation. Therefore, in order to prevent welding defects from occurring, it is necessary to reshape or replace the electrode tip relatively frequently.

However, the shaping of the electrode tip of a spot welding device has conventionally been generally carried out by pressing the tip of the electrode tip against a tip dresser and cutting or grinding it by rotating the shaping blade or shaping grindstone of the tip dresser around the central axis of the electrode tip. This method provides excellent plastic surgery, but it requires a relatively long time for each plastic surgery.
This causes a decrease in the operating rate of the welding line, and also causes the electrode tips to wear out more frequently, causing the electrode tips to be replaced more frequently.

In many cases, the electrode tip is fixed to the electrode holder by inserting its tapered part into the tapered hole of the electrode holder, and the electrode tip cannot be easily removed from the electrode holder. It is impossible to replace the welding line while the welding line is in operation. Therefore, in the conventional multi-point automatic spot welding method using such a welding robot, it is necessary to temporarily stop the operation of the welding line in order to replace the electrode tip. This causes a decrease in the operating rate of the equipment.

In view of the above-mentioned problems in the conventional automatic spot welding method, the present invention enables the shaping of electrode tips to be carried out quickly without large amounts of wear and tear.
Therefore, the present invention provides an improved automatic spot welding method that can shorten the time for shaping the electrode tip, reduce the frequency of replacing the electrode tip, and further eliminate welding defects due to wear and plastic deformation of the electrode tip. It is intended to.

According to the present invention, in an automatic spot welding method in which a welding robot automatically performs multi-point welding, the welding robot indexes a welding gun to an electrode tip shaping gauge, and inserts the electrode tip into the electrode tip. The method is characterized by including the step of shaping the electrode chip in-line by plastic deformation processing imitating the electrode chip shaping gauge by inserting it into a shaping gauge and pressing it against the electrode chip shaping gauge. Achieved by automatic spot welding method.

According to the automatic spot welding method of the present invention, by simply pressing the electrode tip against the electrode tip shaping gauge, the electrode tip is plastically deformed in accordance with the electrode tip shaping gauge, as by cold forging. Because the plastic surgery is done,
Electrode tip shaping can be carried out in a shorter time than shaping by cutting or grinding, and by shortening the electrode tip shaping time, the operating rate of the welding line can be improved. Although the shaping of the electrode tip by plastic deformation may not be completed as completely as by cutting or grinding, the shaping of the electrode tip is sufficient to prevent welding defects. Since the removal of material is not involved, the frequency of replacing electrode tips can be reduced without accelerating the wear of the electrode tips, and this also makes it possible to improve the operating rate of the welding line.

The invention will now be described in detail with reference to preferred embodiments and with reference to the accompanying drawings.

FIG. 1 is a conceptual diagram showing an automatic spot welding method according to the present invention, and FIG. 2 is an enlarged vertical sectional view showing an electrode tip shaping gauge used in the automatic spot welding method according to the present invention. In the figure, 1
is a memory regeneration type multi-axis welding robot.In this welding robot, the operator operates the manipulator and teaches in advance, and the work order,
By storing location and other information, the machine is configured to repeatedly perform the work according to a predetermined schedule. This welding robot 1 is rotatable around a rotation axis 2, and is constructed so that its automatic hand 3 can pivot around a pivot axis 4 perpendicular to the plane of the paper of FIG. A welding gun 5 is supported at the tip of the automatic hand 3, and the welding gun 5 is indexed by the welding robot 1 to each welding point position on the workpiece in all postures.
As is well known, the welding gun 5 includes a movable electrode tip 7 that is reciprocated along its longitudinal axis by a pneumatic cylinder 6, and a C-shaped electrode arm 8 that is fixed opposite to the movable electrode tip 7 at the tip end thereof. and a fixed electrode chip 9.

In the automatic spot welding method according to the present invention, the welding gun 5 is sequentially indexed from its home position on the rest tray 10 to each welding point position of the workpiece by the welding robot according to a predetermined schedule. The electrode tip shaping gauge 11 is fixedly placed in close proximity to the resting tray 10 before being returned to its home position after all welding.
will be allocated to. When the welding gun 5 is thus indexed to the electrode tip shaping gauge 11, its movable electrode tip 7 and fixed electrode tip 9 are inserted into the gauge holes 12 and 13 of the electrode tip shaping gauge 11, respectively, and the electrode tip is inserted by the pneumatic cylinder 6. The tip is pressed against the tip shaping gauge 11, whereby the tips of the movable electrode tip 7 and the fixed electrode tip 9 are plastically deformed to follow the shapes of the gauge holes 12 and 13, thereby shaping them.

In the illustrated embodiment, the electrode tip shaping gauge 11 has a substantially cylindrical shape, as shown in detail in FIG. Gauge holes 12 and 13 are provided facing each other. These gauge holes 12
and 13 include tapered portions 15 and 16 that guide the movable electrode tip 7 and the fixed electrode tip 9 to facilitate their insertion, and shaping portions 17 and 18 that shape the tips of the respective electrode tips. I'm here. The shaping parts 17 and 18 are formed in a shape corresponding to the predetermined outer shape of the electrode tips 7 and 9, and when the electrode tips 7 and 9 are pressed against the electrode tip shaping gauge 11 by the pneumatic cylinder 6, the respective electrode tips The distal end portion can be shaped into the predetermined external shape by plastic deformation. The electrode tip shaping gauge is preferably made of various tool steels that are harder than the copper alloy such as beryllium copper that constitutes the electrode tip.

As explained above, according to the automatic spot welding method according to the present invention, the welding gun is indexed to the electrode tip shaping gauge by the welding robot, and the electrode tip is simply pressed against the shaping gauge by the pneumatic cylinder of the welding gun. As the electrode tip is shaped by plastic deformation, the electrode tip can be shaped quickly without stopping the welding line, and welding is faster than conventional automatic spot welding methods. It will be appreciated that line availability can be improved. Furthermore, according to the automatic spot welding method of the present invention, the electrode tip is maintained in a predetermined external shape by shaping without material removal, so the frequency of replacing the electrode tip can be reduced, and it is also possible to The occurrence of various welding defects due to defects can be prevented. It should be noted that the shaping of the electrode tip may be performed before it is indexed to the first welding point position on the workpiece, and may be performed not every welding cycle but every few welding cycles.

Although the present invention has been described above in detail with reference to specific embodiments thereof, the present invention is not limited to such embodiments, and various modifications and omissions can be made within the scope of the present invention. This will be obvious to those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing an automatic spot welding method according to the present invention, and FIG. 2 is an enlarged vertical sectional view showing an electrode tip shaping gauge used in the automatic spot welding method according to the present invention. DESCRIPTION OF SYMBOLS 1...Welding robot, 2...Rotation axis, 3...Auto hand, 4...Pivotal axis, 5...Welding gun, 6...Pneumatic cylinder, 7...Movable electrode tip, 8...Electrode arm, 9...Fixed electrode chip, 10... Pausing tray, 1
DESCRIPTION OF SYMBOLS 1... Electrode chip shaping gauge, 12, 13... Gauge hole, 14... Center axis line, 15, 16... Taper part, 1
7, 18... Orthopedic department.

Claims (1)

[Claims] 1. In an automatic spot welding method in which a welding robot automatically performs multi-point welding, the welding robot indexes a welding gun to an electrode tip shaping gauge,
The electrode chip is inserted into the electrode chip shaping gauge and pressed against the electrode chip shaping gauge, thereby shaping the electrode chip in-line by plastic deformation processing that follows the electrode chip shaping gate. An automatic spot welding method characterized by: