JPH0446682A - Arm rotation hinge shaft device for spot welding gun - Google Patents

Abstract

PURPOSE:To improve durability of a main shaft part by giving energizing force to the same direction as axial line of a hinge pin to thrust washers at inside or outside of forky parts in gun arms to adjust gap developed in sliding face from outer part. CONSTITUTION:By utilizing bearings 5 inserted at between the inner diameter of forky parts in the gun arms 3, 4 and the hinge pin 6, casing of an inner ring 12 or an outer ring 13, etc., laid as concentrical as the bearing is pushed to the same direction as the axial line of hinge pin 6 with pushing means. By this method, the thrust washers 8a at between the above forky parts can be pushed from side faces. Therefore, gap developed at the sliding face of washer can be simply fastened and center difference between the electrodes developed at tip part of the gun arm can be prevented. Further, in the case of assembling an arm rotary hinge shaft part 10, as the gap between the forky parts is made to be as less as possible, trouble, which the thrust washer is driven in by making this tendency of minus size, is eliminated and the assembling work can be facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rotating shaft device for a gun arm of an X-type spot welding gun. Specifically, this is to prevent misalignment of 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, the gun arm 3 having the negative electrode tip 1 rotates 40 revolutions of the gun arm having the other electrode tip 2. It is inserted between the two forks forming the pivot device 10, passes through the hinge pin 6 common to the bearing 5 attached to the through hole of each arm, and is inserted between each arm 3.4 and the gun support bracket 7. An insulating thrust washer 8 fixed by each rotation stopper pin P is inserted, and both ends of the hinge pin 6 are fastened to the gun support bracket 7 via a screw N. Then, the gun arm 3.4 is rotated around the hinge pin 6 by the pressurizing cylinder 9 connected to the rear ends of both arms to apply the necessary pressurizing force for welding between the pair of electrode tips 1.2. I do.

(Problem to be solved by the invention) However, the recent trend is that spot welding is performed at high speed by robots at a rate of one point every two seconds, and combined with problems in teaching the gun welding point position, the rotational axis of the gun arm When an abnormal load is applied and the sliding surfaces between the thrust washers on the main shaft wear out, a gap is created, and the play causes misalignment of the tip of the electrode tip, which adversely affects the welding result.

When the thrust washer becomes worn in this way, it is desirable to replace it with a new one, but since it is not possible to stop the operating line each time, as a last resort, it is necessary to tighten both nuts N on the outside of the gun bracket. By tightening the screws from the beginning, we have tried to avoid stopping the line as much as possible.

However, even if this method was tightened from both ends, only the gun support bracket would be tightened due to the rigidity of the two branches, and even if I tried to correct the misalignment of the electrode tip at the tip of the upper and lower arms, which was important, I could not do it. .

(Means for Solving the Problems) Therefore, the present invention has been improved in order to solve the problems inherent in the above-mentioned prior art. Explaining by number,
One gun arm 3 is inserted between two prongs of the other gun arm 4, and the two prongs are rotatably supported via a common hinge pin 6, and these two gun arms 3. In the X type spot welding gun, which performs pressure welding by rotating around the hinge pin 6, the gun pressure necessary for welding is generated between the electrode tips 1.2 attached to the tip of the gun arm,
Each gun arm 3 is attached to the inside and/or outside of the fork.
．． A thrust washer 8 is arranged on the same axis as the hinge pin 6, and a pressing means is provided to apply a force from a direction substantially perpendicular to the side surface of the thrust washer 8. A technical measure was taken to eliminate the gap created on the sliding surface of the thrust washer 8 by moving the thrust washer 8 in the direction of the same axis as the hinge pin.

(Function) In the present invention, the bearing 5 inserted between the inner diameter of the two forks of the gun arm 3.4 and the hinge pin is used, and the casing such as the inner ring 12 or the outer ring 13, which is concentric with the bearing, is pressed by pressing means. By pressing in the same direction as the axis of the hinge pin, the thrust washer 8a between the forks can be pressed from the side. Therefore, the gap created on the sliding surface of the washer can be easily tightened, and misalignment between the electrodes that occurs at the tip of the gun arm can be prevented. Also, when assembling the arm rotation axis,
This eliminates the need to make and drive a thrust washer with a slightly negative angle in order to minimize the gap between the two forks, making assembly easier.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. Third
The figure is a cross-sectional view specifically showing an embodiment of the rotating shaft device according to the present invention, and in this case, thrust washers are arranged on the inside and outside of the bifurcation of the gun arm.

Note that, among the components shown in FIG. 3, components that are the same as those in the prior art are designated by the same reference numerals and numbers, and details will be omitted.

This rotation axis device 10 has two gun arms 3.4 attached to a gun support bracket 7.7, which is made up of two parallel plates and supported by an operating arm (not shown) of the robot, through a common hinge pin 6. Rotatably supported. In this case, one gun arm 3 is inserted between the two forks of the other gun arm 4, and a hinge pin 6 passes through the two forks, and both sides of the hinge pin 6 are supported by gun support brackets 7. A nut N is screwed into this threaded part, and by tightening this nut from both sides, a friction occurs on the sliding surface between adjacent thrust washers 8C%8d placed on the outside of the fork. Try to make the gap smaller.

Also, the inner diameter of the two forks of each arm 3.4 through which the main shaft 6 passes is 0.
A bearing bearing 5 is inserted into each of the bearings. Two stacked insulating thrust washers 8 are fixed to each gun arm 3.4 and support bracket 7.7 on the inside and outside of the bifurcation, and the sliding surfaces where the adjacent thrust washers 8a, 8b and 8C18d face each other. rotates when the gun is pressurized and gradually wears out, creating a gap.

Pressing means 11 are provided on both sides of the gun support bracket 7. This pressing means 11 consists of a plurality of bolts B inserted from outside in the same direction as the axis of the hinge pin 6 around the hole through which the hinge pin 6 passes, and the tip of the bolt B is connected to the bearing bearing of the gun arm 4. By tightening this bolt B from both sides of the support bracket, the inner ring 12 is directly moved by the pressing force, and the adjacent thrust washer is moved. 8a can be tightened from the right angle direction. Note that the pressing means may be other than a bolt, such as a spring.

The rotation axis device of the spot welding gun having such a configuration includes a thrust washer 8a between the two prongs of the gun arm 3.4,
8b is worn out and a gap is created between the thrust washers, by tightening the pin B of the pressing means 11, the bolt tip will move the inner ring 12 of the bearing inwardly along the main axis via the pressing ring 14. Move the inner ring 12
One thrust washer 8a that is in contact with is pressed inward. This allows the adjacent washers 8a and 8b to
The gap between the two can be reduced to zero. In addition, to adjust the gap between the thrust washers 8C and 8d placed on the outside of the forks, the nuts N of the hinge pins on the outside of the gun support bracket 7.7 are 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 placed on the outside of the fork. The hinge pin 6 is integrally formed with the gun arm 3 inserted between the two legs, and both sides of the hinge pin 6 are supported by gun support brackets 7. Bearings 5 are inserted into the inner diameter of the support bracket through which the hinge pin 6 is inserted and the inner diameter of the bifurcated inner diameter, and both sides of the hinge pin 6 supported by the gun support bracket 7 are surrounded by a casing 16 equipped with a pressing means 11, A ring-shaped thrust washer 18 is arranged on the surface facing the side surface of the bolt B, and the ring-shaped thrust washer 18 comes into contact with the thrust washer by directly receiving the pressing force from the tightening of the bolt B, and the sliding surface that this thrust washer contacts maintains lubricity. A grease reservoir 19 is formed therein, and a space 20 around the thrust washer 18 surrounded by the casing 16 is also filled with lubricant such as grease. Further, a grease passage 22 is formed which communicates with a grease supply nipple 21 so that grease can be supplied to each bearing 5 from inside the hinge pin 6 as well. 22 indicates a plastic plug of the grease supply nipple.

Although the first embodiment of the present invention shows a mode in which only the inner ring 12 of the bearing 5 is pressed, the technical principle of the present invention is not limited to this, and the outer ring 13 concentrically with the bearing is pressed. or the sliding bearing itself or the bearing 5 which is integrally constructed with the thrust washer 8 as shown in FIG. As shown in FIG. 6, in the case of a double-pull spot welding gun, a single thrust washer 8 placed in
It is also possible to tighten bolt B directly.

(Effects of the Invention) As explained above, according to the present invention, the shaft of the hinge pin is connected to the thrust washer arranged on the inside and/or outside of the bifurcation of the gun arm in the rotation axis device of the gun arm of the X type spot welding gun. By applying a biasing force in the same direction as the core wire, the gap created on the sliding surface of the thrust washer can be adjusted very easily from the outside. Therefore, compared to conventional rotating shaft devices, the thrust washer can be tightened normally (parallel) directly or indirectly through a pressing means such as a bolt, regardless of the rigidity of the two forks, so the thrust washer can be tightened normally (in parallel). It is possible to always maintain a satisfactory condition.

Also, when assembling the arm rotation axis, there is no need to make and drive a thrust washer with a slightly negative angle in order to minimize the gap between the two forks.

Therefore, the durability of the main shaft portion, which is the most fatal blow to the welding gun, can be significantly improved.

[Brief explanation 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 the main part of a conventional gun arm rotation axis device taken along the arrow A-A in Fig. 1, and Fig. 3 FIG. 2 is a cross-sectional view of a main part showing an example of a rotation axis device for a gun arm according to the present invention. FIG. 4 is a sectional view of the main part on the right side showing another embodiment of the present invention, which is symmetrical. FIG. 5 is a perspective view showing a bearing integrated with a thrust washer. FIG. 6 is a sectional view of a main part showing an embodiment of a rotation axis device of a porta-pull spot welding gun. [Explanation of symbols] 1.2・0. Extreme tip 3.4...Gun arm 5.
... Bearing 666, hinge pin 7 ... Gun support bracket 8 ... Insulating thrust washer 9 ... Pressure cylinder 10 ... Arm rotation axis device 11 ... Pressing means 12 ... Inner ring 1
3...Outer ring 14...Press ring 15...Insulating liner 16...Casing 18°/Thrust washer 19...Grease reservoir Σ

Claims (1)

[Claims] One gun arm is inserted between the two prongs of the other gun arm, and the two prongs are rotatably supported via a common hinge pin, and these two gun arms are rotated around the hinge pin by a pressurized cylinder. In the X-type spot welding gun, which performs pressure welding by generating the necessary gun pressure for welding between the electrode tips attached to the tip of the gun arm, there is a joint between each gun arm on the inside and/or outside of the forks. An insulating thrust washer is disposed on the same axis as the hinge pin, and pressing means is provided to directly or indirectly apply a force from a direction substantially perpendicular to the side surface of the thrust washer, so that the thrust washer is pressed against the hinge pin. An arm rotation axis device for a spot welding gun that eliminates the gap created on the sliding surface of the thrust washer by moving it in the same axis direction as the thrust washer.