JPH0763852B2 - Spot welding gun arm rotation pivot device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary pivot device for a gun arm of an X type spot welding gun, and in particular, adjusts a clearance caused by wear of a thrust washer due to rotational movement of a main shaft portion, The purpose is to prevent core misalignment at the tip of the electrode tip.

(Prior Art) In a conventional X-type spot welding robot gun, for example, as shown in FIGS. 1 and 2, a gun arm 3 having one electrode tip 1 rotates a gun arm 4 having the other electrode tip 2. The bearing 5 inserted between the two forks constituting the pivot device 10 and attached to the through hole of each arm.
Insulating thrust washers 8 fixed by anti-rotation pins P are inserted between the arms 3 and 4 and the gun support bracket 7, and the both ends of the hinge pins 6 are connected to the gun pins. It is fastened and fixed to the support bracket 7 via a nut N. Then, the gun arms 3 and 4 are rotated around the hinge pin 6 by the pressurizing cylinder 9 connected to the rear ends of both arms to apply a pressure force required for welding between the pair of electrode tips 1 and 2 to perform welding. I do.

(Problems to be solved by the invention) However, the recent tendency is that spot welding is performed at a high speed by a robot at a rate of 1 point every 2 seconds, and in addition, due to the inconvenience of the teaching of the gun striking position, the rotation axis of the gun arm is When an abnormal load is applied and the sliding surfaces between the thrust washers of the main shaft part are worn, a gap is created, and the play causes a misalignment at the tip of the electrode tip, which adversely affects the welding result.

When the thrust washer wears like this, it is desirable to replace it with a new washer, but it is not possible to stop the operation line each time, so both nuts on the outside of the gun bracket should be stopped as a conservative measure. I tried to avoid the line stop as much as possible by tightening it from.

However, in this method, even if the nuts N are tightened from both sides, only the gun support bracket is tightened because the fork has rigidity, and it is impossible to correct the misalignment of the electrode tips at the tips of the essential upper and lower arms.

(Means for Solving the Problems) Therefore, the present invention has been improved in order to solve the problems inherent in the above-mentioned conventional technology, and its specific configuration is shown in FIG. To explain in turn,
One gun arm 3 is inserted between the two forks of the other gun arm 4, and the two forks are rotatably supported via a common hinge pin 6, and these two gun arms 3 and 4 are supported by a pressure cylinder 9. In an X-type spot welding gun, which rotates by rotating the hinge pin 6 as a center to generate a gun pressure required for welding between the electrode tips 1 and 2 attached to the tip of the gun arm to perform pressure welding,
A thrust washer 8 that insulates the gun arms 3 and 4 from each other is disposed on the inner side and / or the outer side of the bifurcation on the same axial core line as the hinge pin 6. By providing a pressing means for applying a biasing force from a direction intersecting at a right angle and moving the thrust washer in the same axial core line direction as the hinge pin, a technical means of eliminating a gap generated on the sliding surface of the thrust washer 8 is taken. is there.

(Operation) In the present invention, the bearing 5 inserted between the inner diameter between the forks of the gun arms 3 and 4 and the hinge pin is used, and the casing such as the inner ring 12 or the outer ring 13 concentric with the bearing is pressed by the pressing means. By pressing in the same direction as the axis of the hinge pin, the thrust washer 8a between the two forks can be pressed from the side surface. Therefore, the gap generated on the sliding surface of the washer can be easily tightened, and the misalignment between the electrodes at the tip of the gun arm can be prevented. In addition, when assembling the arm rotation pivot portion, the work of making a thrust washer in a minus manner and driving it in order to minimize the gap between the forks is eliminated, and the assembling work becomes easy.

(Example) Hereinafter, the Example of this invention is described based on drawing. Third
The figure is a sectional view specifically showing an embodiment of the rotary pivot device according to the present invention, and in this case, the thrust washer is arranged inside and outside the forked part of the gun arm.

It should be noted that, in the components shown in FIG. 3, the same components as those in the prior art are designated by the same reference numerals and the detailed description thereof will be omitted.

The rotary pivot device 10 includes a gun support bracket 7 and 7 composed of two parallel plates supported by an operation arm (not shown) of a robot, and two gun arms 3 and 4 via a common hinge pin 6. It is rotatably supported. In this case, one gun arm 3 is inserted between the two forks of the other gun arm 4, the hinge pin 6 penetrates the fork, and both sides of the hinge pin 6 are supported by the gun support brackets 7. Is formed,
A nut N is screwed to this threaded portion, and by tightening this nut from both sides, the gap generated on the sliding surface between the adjacent thrust washers 8c, 8d arranged on the outer side of the fork is reduced. There is.

Also, the inner diameter between the two forks of the arms 3 and 4 through which the main shaft 6 penetrates is 0
Bearing bearings 5 are inserted into the respective bearings. Two insulative thrust washers 8 are fixed to each of the gun arms 3 and 4 and the support brackets 7 and 7 on the inside and outside of the fork, and the thrust washers 8a, 8b and 8 are adjacent to each other.
The sliding surfaces that c and 8d face each other gradually rotate during the gun pressurizing operation and wear gradually, creating a gap.

Pressing means 11 are provided on both sides of the gun support bracket 7. The pressing means 11 is composed of a plurality of bolts B inserted from the outside in the same direction as the axis of the hinge pin 6 around the hole through which the hinge pin 6 penetrates, and the tip of the bolt B is the bearing bearing 5 of the gun arm 4. In the form of abutting against the pressing ring 14 inserted at a position contacting the inner ring 12 of
By tightening the bolts B from both sides of the support bracket, the inner ring 12 can be directly moved by the pressing force to tighten the adjacent one thrust washer 8a from the right angle direction. The pressing means may be something other than a bolt such as a spring.

The rotary pivot device of the spot welding gun having the above-described structure is provided with a thrust washer 8a between the forks of the gun arms 3 and 4,
When 8b is worn and a gap is generated between the thrust washers, the bolt B of the pressing means 11 is tightened so that the bolt tip moves the inner ring 12 of the bearing bearing inward through the pressing ring 14 along the main axis. Then, one thrust washer 8a that is in contact with the inner ring 12 is pressed inward. As a result, the gap between the adjacent washers 8a and 8b can be reduced to zero. Further, in adjusting the clearance between the thrust washers 8c and 8d arranged on the outer side of the fork, the nut N of the hinge pin on the outer side of the gun supporting brackets 7 and 7 is tightened from both sides as in the conventional case.

Next, FIG. 4 shows another embodiment of the present invention, in which a free insulating liner 15 is inserted inside the fork and a thrust washer 8 is arranged outside the fork. The hinge pin 6 is formed integrally with the gun arm 3 inserted between the forks, and both sides of the hinge pin 6 are supported by the gun support brackets 7. The bearing 5 is inserted into the inner diameter of the support bracket through which the hinge pin 6 is inserted and the inner diameter of the fork, and both side surfaces of the hinge pin 6 supported by the gun support bracket 7 are surrounded by the casing 16 having the pressing means 11. A ring-shaped thrust washer 18 is arranged on the surface facing the side surface of 6 to directly contact with the pressing force by the tightening of the bolt B, and the sliding surface with which the thrust washer contacts maintains lubricity. A grease reservoir 19 is formed for this purpose, and the peripheral space 20 of the thrust washer 18 surrounded by the casing 16 is also filled with a lubricant such as grease. Further, a grease passage 22 communicating with the grease supply nipple 21 is formed so that the grease can be supplied to each bearing 5 from the inside of the hinge pin 6 as well. 22 indicates a plastic plug of the nipple for supplying grease.

Although the first embodiment of the present invention shows the mode in which only the inner ring 12 of the bearing bearing 5 is pressed, the technical principle of the present invention is not limited to this, and the outer ring 13 concentric with the bearing is used. A pressing means for applying an urging force to the casing, or the like, or an urging force may be applied to the sliding bearing itself or to the bearing 5 integrally formed with the thrust washer 8 as shown in FIG. As shown in FIG. 6, in the case of a portable spot welding gun, it is also possible to directly fasten one thrust washer 8 arranged in the fork with a bolt B.

(Effects of the Invention) As described above, according to the present invention, the axis of the hinge pin is different from the thrust washer disposed inside and / or outside the forked part of the gun arm of the rotary pivot device of the gun arm of the X type spot welding gun. By applying the urging force in the same direction as the core wire, the gap generated on the sliding surface of the thrust washer can be adjusted very easily from the outside. Therefore, as compared with the conventional rotary pivot device, the thrust washer can be normally (directly) tightened directly (or in parallel) via the pressing means such as the bolt regardless of the rigidity of the fork, so that the contact of the thrust washer can be prevented. The state can be kept always satisfactory. Also, when assembling the arm rotation pivot part, it is not necessary to make a thrust washer in a minus manner and drive it in order to make the gap between the forks as small as possible.

Therefore, the durability of the main shaft portion that is most fatally hit by the welding gun can be significantly improved.

[Brief description of drawings]

FIG. 1 is a front view showing a general configuration example of an X type spot welding gun. FIG. 2 is a cross-sectional view of a main part of a conventional rotary pivot device for a gun arm as viewed from the direction of arrow AA in FIG. FIG. 3 is a cross-sectional view of essential parts showing an example of a rotary pivot device for a gun arm according to the present invention. FIG. 4 is a right side sectional view showing the other embodiment of the present invention, which is symmetrical. FIG. 5 is a perspective view showing a bearing having a structure integrated with a thrust washer. FIG. 6 is a sectional view of an essential part showing an embodiment of a rotary pivot device of a portable spot welding gun. [Explanation of reference symbols] 1, 2 ... Electrode tip, 3, 4 ... Gun arm, 5 ...
Bearing, 6 ... Hinge pin, 7 ... Gun support bracket, 8 ... Insulating thrust washer, 9 ... Pressure cylinder, 10 ... Arm rotation pivot device, 11 ... Pressing means, 12 ...
… Inner ring, 13 …… Outer ring, 14 …… Pressing ring, 15 …… Insulation liner, 16 …… Casing, 18 …… Thrust washer, 19
…… Grease pool, 20 …… space, B …… bolt

Claims (1)

[Claims] 1. One gun arm is inserted between two forks of the other gun arm, and the two forks are rotatably supported via a common hinge pin, and these two gun arms are hinged by a pressure cylinder. In an X type spot welding gun in which the gun pressure required for welding is generated between the electrode tips attached to the tip of the gun arm by rotating to the center and pressure welding is performed, the inside and / or outside of the bifurcation is respectively A thrust washer which insulates the gun arms from each other is arranged on the same axis as the hinge pin, and a pressing means for directly or indirectly applying a biasing force from a direction intersecting the side face of the thrust washer at a substantially right angle is provided. It was generated on the sliding surface of the thrust washer by moving the thrust washer in the same axis direction as the hinge pin. Arm rotation pivot device of the spot welding gun so as to eliminate between.