JP2003001429A - C-c type electric welding gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a C-C type electric welding gun in which the configuration is simple, the cost is low, the pressure and the opening stroke in each welding gun are freely and easily adjustable, the pressure on electrodes is not affected by the wear of the electrodes and a bearing and the deflection, etc., of a gun arm changing at each pressure, the pressure can be correctly output to the preset value by a simple control, and the stable pressure can be obtained. SOLUTION: In the C-C type electric welding gun having a pressing shaft 8 which is advanced/retracted by the drive of a motor 7, the axes of the electrodes 11 and 12 are offset to the axis of the pressing shaft, the electrodes 11 and 12 are disposed in the vertical direction on an electrode part on the pressing shaft side, two electrodes 13 and 14 are disposed facing each electrode from the fixed side to form two sets of C-type electric welding gun, and the upper and lower electrodes are separately used when the pressing shaft is protruded and when the shaft is retracted.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a C--C type electric welding gun having a pressurizing shaft which moves forward and backward by driving an electric motor. 2. Description of the Related Art Conventionally, a CC having a pressurizing shaft (movable arm) which moves forward and backward by a piston rod of an air cylinder.
A mold air welding gun is known as disclosed in, for example, Japanese Utility Model Laid-Open No. 63-16580 (hereinafter referred to as the former). A CC type electric welding gun having two pressurizing shafts (movable arms) that move forward and backward by driving of an electric motor is also disclosed in Japanese Patent Application Laid-Open No. 200-200.
It is publicly known as shown in JP-A-153365 (hereinafter referred to as the latter). In the former, since the piston rod from the air cylinder is used for driving the gun arm, the adjustment of the pressing force, the adjustment of the opening stroke, and the driving unit are performed. There is a problem that it is difficult to maintain the airtightness of a certain cylinder. In the latter case, a speed reducer is used to
The rotation on the output side is changed from a swinging lever to a linear motion via a roller and a guide member, and the two pressure shafts are moved forward and backward, so that the structure is complicated. Since the swing lever, roller, guide member and the like intervene, the outer dimensions of the welding gun become large, the chance of interference with the jig as a welding gun increases, and the use of the gun is limited. There is a risk that the manufacturing cost will increase. The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a C-C type having a pressurizing shaft which moves forward and backward by driving an electric motor. With electric welding guns, the cost is simple and the cost is low.The adjustment of the pressing force and the opening stroke of each welding gun is free and extremely easy, and it changes depending on the wear of the electrodes and bearings and each pressurization. C-C type electric welding that can output accurate pressure with the set pressure by simple control without affecting the electrode pressure due to the deflection of the gun arm, etc. It is intended to provide cancer. In order to achieve the above object, a C-C type electric welding gun according to the present invention has an electrode whose center axis is eccentric with respect to the center axis of a pressurizing shaft, and which has an eccentric shape. The electrodes are arranged vertically in the electrode part on the pressure axis side, and two electrodes are respectively opposed to the respective electrodes from the fixed side to form two pairs of C-type electric welding guns. Can be selectively used when the pressure shaft is protruded and when it is stored. Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a side view of an essential part of a CC type electric welding gun having a pressurizing shaft which moves forward and backward by driving an electric motor according to the present invention, and FIG. 2 is a plan view of the essential part. In FIGS. 1 and 2, reference numeral 1 denotes a gun bracket. One end of the gun bracket 1 is connected to a wrist of a robot, and a welding transformer 2 is held at an intermediate portion. The part of the drive unit 3 of the pressure shaft
4 is connected. Therefore, gun bracket 1
And case 4 are the fixed side of the welding gun. A rear end of a fixed arm 5 is mounted on the front and rear side surfaces of the case 4 of the drive unit 3, and another fixed arm 6 is mounted on a front surface thereof. However,
Any of these fixed arms 5 and 6 can be appropriately selected and mounted on the fixed side. An electric motor 7 is fixedly arranged in parallel with the case 4 of the drive unit 3. In the case 4 of the drive unit 3, a rotational force such as a ball screw, a ball nut, and a pressure shaft integrally formed with the ball screw is reciprocated by the pressure shaft 8. A well-known drive mechanism for replacing power is provided. The rotational force from the rotating shaft of the electric motor 7 applies a rotational force to the drive unit 3 via a belt 9. One end of an electrode holding arm 10 is attached to the tip of the pressure shaft 8, and the other end of the electrode holding arm 10 has an electrode 11 in the vertical direction. , 1
2 are attached respectively. Therefore, the center axes of the electrodes 11 and 12 are eccentric with respect to the center axis of the pressing shaft 8. Electrodes 13 and 14 are attached to the distal ends of the fixed arms 6 and 5 so as to face the electrodes 11 and 12 on the pressure shaft 8 side, respectively. Therefore, two pairs of welding guns are used: a C-type electric welding gun on the fixed arm 5 side and the pressing shaft 8 side, and a C-type electric welding gun on the fixed arm 6 side and the pressing shaft 8 side. Is formed. In the C-C type electric welding gun having the above-described configuration, the electric motor 7 is driven from the state shown in FIG. After the conversion, the pressure shaft 8 is further protruded from the drive case 4 to bring the electrode 12 closer to the electrode 14, and the electrode 12 is brought into contact with the other surface of the work (not shown) contacting the electrode 14. After the electrodes 12 are brought into contact with each other, the work is pressed by both the electrodes 12 and 14 to perform welding. When this welding is completed, the motor 7 is rotated in the reverse direction so that the pressure shaft 8 is slightly retracted and stored in the drive case 4, and the next work is performed.
The electrode is prepared to be welded by the electrodes 12 and 14. When welding is performed between the electrodes 11 and 13, the pressure shaft 8 is retracted and stored in the drive case 4 in a relatively large manner, and the wire that is in contact with the electrode 13 is moved. After the electrode 11 is brought into contact with the other surface of the electrode (not shown),
In steps 1 and 13, the work is pressurized and welded. When the welding is completed, the electric motor 7 is rotated in the reverse direction so that the pressurizing shaft 8 is slightly advanced from the inside of the drive case 4, so that the next work is prepared to be welded by the electrodes 11 and 13. As described above, both the C-type electric welding gun between the fixed arm 5 and the pressing shaft 8 and the C-type electric welding gun between the fixed arm 6 and the pressing shaft 8 are used. Can be operated arbitrarily, and the electrode stroke at that time can be freely selected. Further, both C-type electric welding guns can be freely used in common. FIG. 3 is a side view of an essential part of another embodiment of the CC type electric welding gun having a pressurizing shaft which moves forward and backward by driving the electric motor according to the present invention. This embodiment differs from the previous embodiment in the means for moving the pressing shaft 8 back and forth by driving the electric motor 7. That is, reference numeral 21 denotes a speed reducer.
A swing lever 22 is attached to the output side of the device, and a cam follower 23 is attached to the tip of the swing lever 22. On the other hand, the pressure shaft 8 is prevented from rotating around the drive case 4, and a groove cam 25 having a groove 24 that comes into contact with the cam follower 23 is attached to the rear end of the pressure shaft 8. Therefore, the rotational force from the rotating shaft of the electric motor 7 is transmitted to the speed reducer 21 via the belt 9, where it is decelerated, and operates to swing the swing lever 22. The swinging movement of the swinging lever 22 causes the pressing shaft 8 to move forward and backward through the cam follower 23 and the groove cam 25. Note that, of the members in this embodiment, those substantially the same as those described in the previous embodiment are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment as well, although there is a difference in the power transmission mechanism from the electric motor 7 to the pressurizing shaft 8, the welding gun is a C-shaped electric motor between the fixed arm 5 side and the pressurizing shaft 8 side. Two pairs of C-type electric welding guns, a welding gun and a C-type electric welding gun on the fixed arm 6 side and the pressing shaft 8 side, are formed, and the fixed arm 5 side and the pressing shaft 8 side are formed. And the C-type electric welding gun on the fixed arm 6 side and the pressurizing shaft 8 side can be operated arbitrarily, and the electrode stroke at that time can be used. You can choose freely. Further, both C-type electric welding guns can be freely used in common. According to the present invention, the center axis of the electrode is eccentric with respect to the center axis of the pressing shaft, and the electrodes are arranged vertically in the electrode portion on the pressing shaft side. The two electrodes are opposed to each other from the fixed side to form two pairs of C-type electric welding guns, and the upper and lower pairs of electrodes can be selectively used when the pressurizing shaft is protruded and stored. The structure is inexpensive, the adjustment of the pressing force and the adjustment of the opening stroke of each welding gun are free and extremely easy, and the wear of the electrodes and bearings, the bending of the gun arm that changes with each press, etc. Thus, the electrode pressing force is not affected, the accurate pressing force is output with respect to the pressing force set by the simple control, and the C-C type electric welding gun can obtain a stable pressing force.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a main part of an embodiment of a CC electric welding gun according to the present invention. FIG. 2 is a plan view thereof. FIG. 3 is a side view of a principal part of another embodiment of the CC electric welding gun according to the present invention. [Description of Signs] 1, 4 Fixed side (gun bracket, case) 5, 6 Fixed arm 7 Motor 8 Pressurizing shafts 11, 12, 13, 14 Electrodes

Claims (1)

Claims: 1. A C-C type electric welding gun having a pressurizing shaft which moves forward and backward by driving an electric motor, wherein the center axis of the electrode is eccentric with respect to the center axis of the pressing shaft. Electrodes are arranged vertically in the electrode portion on the pressure axis side, and two electrodes are respectively opposed to the respective electrodes from the fixed side to form two pairs of C-type electric welding guns. C. The electrode can be selectively used when the pressure shaft protrudes and when it is stored.
-C type electric welding gun.