JPH0217755Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rotating shaft portion of a gun arm of an X-type spot welding gun. In particular, when performing welding after positioning a spot welding gun using an industrial robot, manipulator, etc., if the gun is pressurized when the spot welding gun is not at an appropriate angle to the workpiece, the rotational axis of the gun arm may become unstable. The main purpose of the present invention is to reduce the surface pressure of the bearing in the shaft portion against the twist applied to the shaft portion, and to minimize the amount of misalignment between the electrode chips due to wear of the bearing.

The external shape of the conventional X-type spot welding gun is almost the same as that of the spot welding gun according to the present invention, so for convenience, reference is made to FIG. 9, the gun arm 3 having the electrode tip 1 on one side is connected to the bifurcated support pieces 4a, 4b of the gun arm 4 having the electrode tip 2 on the other side.
A hinge pin 6 is commonly passed through a bearing 5 which is inserted between the arms 3 and 4 and installed in the through hole of each arm, and an insulating thrust washer 8 is inserted between each arm 3, 4 and the gun support bracket 7. The common structure is that both ends of the hinge pin 6 are fixed to the gun support bracket 7.
A pressure cylinder 9 connected to the rear ends of both arms rotates each arm 3, 4 about a hinge pin 6 to open and close the pair of electrode tips.

However, in the past, when using an industrial robot or manipulator to teach a spot welding gun the correct posture and angle for the spot welding point on the workpiece, the gun was often pressurized at an incorrect posture and angle. When the gun is pressurized, the rotation axis of the gun arm is twisted, causing abnormal wear on the bearing, and furthermore, the gun arm is rotated tens of thousands to tens of millions of times around the hinge pin fixed in position on the gun bracket. As the rotational motion is repeated, the bearing of the gun arm will gradually wear out, and as the amount of wear increases, the amount of misalignment between the electrode tips at the tip of the gun arm will gradually increase, which will adversely affect the welding result. become.

This invention was devised to reduce the amount of misalignment between electrode tips caused by wear of the rotating shaft of the gun arm of an X-type spot welding gun. A common hinge pin is passed through the gun arm and the gun support bracket for supporting it from both sides.
The other gun arm inserted between the bifurcated support pieces formed on one gun arm is integrally connected to the hinge pin, and a bearing into which the hinge pin is rotatably fitted is fitted into one gun arm and the gun support bracket. To provide a rotating shaft portion of a gun arm of a spot welding gun.

Hereinafter, embodiments of the present invention will be described based on the drawings. FIG. 1 is a side view showing the entirety of the X-type spot welding gun according to the present invention, FIG. 2 is a bottom view thereof, and FIG. 3 is a view showing the rotation axis of the X-type spot welding gun according to the present invention. FIG.

The two gun arms 3 and 4 are supported via a rotating shaft 10 by a gun support bracket 7 attached to, for example, an industrial robot, so as to open and close using a hinge pin 6 as a fulcrum.

This rotating shaft pivot portion 10 is constructed such that the other upper arm 3 is located between the bifurcated support pieces 4a and 4b of one lower arm 4, and the gun support bracket 7 is supported from both sides of the bifurcated support pieces 4a and 4b, respectively. Each arm 3, 4 and the gun support bracket 7 have an insertion hole for a hinge pin 6, and a bearing 5 is formed in the bifurcated support pieces 4a, 4b of the lower arm 4 and the insertion hole of the gun support bracket 7. Each is fitted. These bearings 5 and upper arm 3
The hinge pin 6 is inserted into the insertion hole, and as shown in FIGS. 3 to 5, the upper arm 3 and the hinge pin 6 are fixed integrally using a roll pin 11 or a tightening means 12 such as a split piece clamp. has been done. On the other hand, an insulating thrust washer 8 is interposed between each arm 3, 4 and the gun support bracket 7, and as shown in FIGS. 6 to 8, this insulating washer 8 includes a hinge pin. In addition to the insertion hole 8b, a large number of through holes 8a or non-penetrating holes 8c are bored at appropriate intervals in the thickness direction of the plate, and lubricating grease is sealed in these holes 8a or 8c to improve the lubricity of the sliding surface. It also has the function of releasing foreign matter such as spatter generated during welding and abrasion powder generated on the sliding surface of the insulating washer from the sliding surface.

The main body of a pressure cylinder 9 is pivotally supported at the rear end of the upper arm 3, and the rear end of the lower arm 4 is connected to a piston rod 9a of the pressure cylinder 9.

Next, the movement of the rotation shaft portion 10 of the spot welding gun constructed as above will be explained. When the piston rod 9a is moved forward and backward by the pressurizing cylinder 9,
Each arm 3, 4 opens and closes around the hinge pin 6, but the upper arm 3 moves in unison with the hinge pin 6.
Both ends of the hinge pin 6 are attached to gun support brackets 7.
One lower arm 4 is rotatably supported by bearings 5 of bifurcated support pieces 4a and 4b.
A pressing force necessary for welding is applied between the electrode tips 1 and 2 at the tip of each arm by rotating the outer periphery of the hinge pin 6 inserted through the arm.

As described above, according to the present invention, at the rotation axis of the gun arm of an X-type spot welding gun, the hinge pin is integrated with the other gun arm, which is located between the bifurcated support pieces of one gun arm, by an appropriate tightening means. The span of the bearing at the axis is increased to reduce wear caused by twisting of the bearing, reduce the amount of misalignment between the electrode tips, and the rotation axis of the spot welding gun is fixed. It further improves the service life and provides stable effects on welding quality.

[Brief explanation of the drawing]

FIG. 1 is a side view showing an embodiment of a spot welding gun according to the present invention. Figure 2 is also a bottom view. Third
The figure is a sectional view of the rotating shaft of the spot welding gun of the present invention. FIG. 4 is a sectional view showing an example of a means for tightening the rotating shaft portion. FIG. 5 is a view taken along the line A-A in FIG. FIG. 6 is a side view showing an example of an insulating thrust washer. FIG. 7 is a side view showing an example of the washers. FIG. 8 is a sectional view of a main part showing another embodiment of the above-mentioned washer. FIG. 9 is a cross-sectional view showing the rotation axis of a conventional spot welding gun. FIG. 10 is a sectional view showing another tightening means for the rotating shaft pivot portion. Explanation of symbols, 1, 2... Electrode chip, 3, 4... Gun arm, 5... Bearing, 6... Hinge pin, 7... Gun support bracket, 8... Insulating thrust washer, 9... Pressure cylinder, 10... Rotating shaft pivot, 8
a, 8c...Foreign object receiving and lubricating grease reservoir.

Claims (1)

[Scope of utility model registration request] One gun arm and the other gun arm, which is inserted between the two legs formed in this arm, are pivotally supported so as to be movable around a hinge pin that passes through the gun support bracket in common, and is supported at the tip of each arm. In a spot welding gun in which a pair of electrode tips are opened and closed by the movement of a gun arm by a pressurized cylinder, one of the gun arms and the gun support bracket is equipped with a bearing into which a hinge pin is rotatably inserted. The other gun arm is a spot welding gun that is fixedly integrated with the hinge pin.