JPH0588773U - Double head welding gun - Google Patents

Abstract

(57) [Summary] [Objective] To provide a double-headed welding gun equipped with two sets of welding electrodes, capable of simultaneously welding two points, and capable of being mounted on a robot. [Constitution] Two piston rods 1 for one cylinder 2
1, 12 are mounted in parallel, and the two piston rods 1
1, 12 and the piston 9 are connected to a first balance link mechanism 10
And the movable electrodes 13 and 1 attached to the tip of each piston rod 11 and 12 by reciprocating the piston 9.
4 and fixed electrodes 15 and 16 arranged to face each movable electrode
The work 19 is clamped between and welded. The respective yokes 5 and 6 on which the fixed electrodes 15 and 16 are installed are connected and supported by a second balance-like link mechanism 17 provided at a position of the cylinder 2 in the piston advancing direction, and the first balance-like link mechanism 10 is provided. By operating together, the operation of clamping the work piece 19 by each electrode can be performed equally and simultaneously.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a double-headed welding gun equipped with two sets of welding electrodes and capable of simultaneously performing two-point resistance welding.

[0002]

[Prior Art]

 When performing spot welding by robot work, a spot welding gun 31 is attached to the robot arm 30 as shown in FIG. 6, the robot arm 30 is driven, and the welding gun 31 is sequentially moved to the welding location. Perform spot welding.

[0003]

[Problems to be solved by the device]

 In conventional spot welding by a welding robot, welding is performed one point at a time by one robot as described above, but spot welding is performed simultaneously at two welding points by one robot. If it can be executed, the welding efficiency will be doubled, and the number of required robots can be halved. To do this, one robot must be equipped with two welding guns, but mounting two welding guns on one robot has restrictions such as limiting the allowable load of the robot. ， It was difficult to realize. Various double-headed welding guns having two sets of welding electrodes have been proposed (see Japanese Utility Model Laid-Open No. 60-46975 and Japanese Patent Laid-Open No. 62-29878), but both limit the allowable load of the robot. There was a demand for a double-headed welding gun that is capable of simultaneously welding two points within the allowable load limit of the robot. The present invention has been made in view of the above problems, and provides a double-headed welding gun equipped with two sets of welding electrodes to enable simultaneous welding of two points and mounting on a robot. With the goal.

[0004]

[Means for Solving the Problems]

 The means adopted by the present invention to achieve the above object is that two piston rods are mounted in parallel in one cylinder, and the two piston rods are reciprocated so that the tip ends of the respective piston rods. In a double-headed welding gun that clamps and welds a work between a movable electrode mounted on the movable electrode and a fixed electrode that is arranged to face each movable electrode, both piston rods and a piston that slides in the cylinder are A second balance-type link mechanism that applies the pressing force of the piston equally to the piston rod and connects each of the yokes to which the fixed electrodes are attached in the advance direction position of the cylinder. It is configured as a double-headed welding gun, which is characterized in that it is connected and supported by a scale-like link mechanism.

[0005]

[Action]

 According to the present invention, two piston rods are mounted in parallel on one cylinder, and the movable electrode mounted on the tip of each piston rod is moved back and forth with respect to the fixed electrode. Even if there is a step in the clamp position of the work due to, the work is clamped equally by the movable electrode and the fixed electrode. That is, since the pressing force of the piston by the cylinder is applied to the piston rod via the first balance-like link mechanism, even if there is a step at the welding site where each movable electrode abuts the work, the first balance-like link mechanism is used. The pressing force is evenly applied to each piston rod by the balance pressurization, and further, each yoke to which each fixed electrode is mounted is connected and supported by the second balance-like link mechanism so that each fixed electrode contacts the work. Even if there is a step in the welding portion to be brought into contact, each fixed electrode can be evenly contacted with the work by the balance support of the second balance-like link mechanism. Therefore, by the first and second balance-shaped link mechanisms, the clamp of the work by each movable electrode and each fixed electrode is equally pressed, and simultaneous energization becomes possible, so that the two points are evenly welded.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention. It should be noted that the following embodiments are examples of embodying the present invention and do not limit the technical scope of the present invention. FIG. 1 shows the structure of a double-headed welding gun according to an embodiment of the present invention. FIG. 1 is a front view showing a cylinder section in section, FIG. 2 is a side view showing the overall structure of a double-headed welding gun, and FIG. FIG. 4 is a cross-sectional view taken along the line AA in FIG. 1 showing the structure of the first balance-like link mechanism, and FIG. 4 is a view showing the structure of the second balance-like link mechanism taken along the line BB in FIG. FIG. 5 and FIG. 5 are energizing circuit diagrams showing connection of energizing circuits to each electrode. First, the overall configuration of the double-headed welding gun according to this embodiment will be described with reference to FIG. In the double-headed welding gun 1, an ecological device 8 is attached to a bracket 3 fixed to a robot arm, and the ecological device 8 supports a gun part including a cylinder 2 so as to be movable in a clamping direction. As shown in FIG. 1, the cylinder 2 has a piston 9 sealed therein, and a first piston rod 11 and a second piston rod 12 are provided so as to penetrate the piston 9 and not hinder the reciprocating movement of the piston. The first piston rod 11 and the second piston rod 12 are connected and reciprocally driven via a balance-like link mechanism 10 provided on the piston 9. A first movable electrode 13 is attached to the tip of the first piston rod 11, and a second movable electrode 14 is attached to the tip of the second piston rod 12. Further, a first yoke 5 and a second yoke 6 are attached to a lower portion of the cylinder 2 via a second balance-like link mechanism 17, and the first movable electrode is attached to a tip of the first yoke 5. A first fixed electrode 15 is provided so as to face 13 and a second fixed electrode 16 is provided at the tip of the second yoke 6 so as to face the second movable electrode 14.

In the above structure, when air is supplied from the pressurizing port 2a of the cylinder 2 and exhausted from the open port 2b, the piston 9 moves in the advancing direction, and the first balance link mechanism 10 attached to the piston 9 is moved. The first and second movable electrodes 13 and 14 attached to the respective tips of the first and second piston rods 11 and 12 to the direction of the first and second fixed electrodes 15 and 16 through You can On the contrary, when the air is supplied from the open port 2b and the air is supplied from the pressurizing port 2a, the piston 9 can be moved in the backward direction. As shown in FIGS. 1 and 3, the first balance-type link mechanism 10 has a first piston at each end of a link 10b rotatably supported at the center by a column 10a provided on the piston 9. When the rod 11 and the second piston rod 12 are loosely fitted and there is a step at the welding site of the work piece 19 as shown in FIG. 1, the first movable electrode 13 and the second movable electrode 13 driven to move forward are moved. Although the advancing position where the electrode 14 abuts on the work 19 is different, the pressure applied to the first and second piston rods 11 and 12 is divided equally due to the inclination of the link 10b of the balance link mechanism 10. Then, the movable electrodes 13 and 14 are evenly contacted with the work 19.

Further, as shown in FIGS. 1 and 4, the second balance-like link mechanism 17 has a link arm rotatably supported at its center by a column 17 a provided at the center of the lower part of the cylinder 2. Both ends of 17b are loosely fitted to the first yoke 5 and the second yoke 6, respectively, and when there is a step at the welding site of the work piece 19 as shown in FIG. 1, the first fixed electrode 15 The contact positions of the second fixed electrode 16 and the second fixed electrode 16 with respect to the work 19 are different. However, due to the balance support by the suspension of the second balance-like link mechanism 17, each of the fixed electrodes 15 and 16 has the work 19. The contact with is made equally. After the work 19 is clamped by the movable electrodes 13 and 14 and the fixed electrodes 15 and 16 having the above-described configuration, welding current is applied to carry out welding. It is configured as shown in FIG. That is, the welding current from the welding transformer 4 is connected in series in the order of the first movable electrode 13, the first fixed electrode 15, the second movable electrode 14 and the second fixed electrode 16, and 2 The welding points are welded at the same time. Therefore, as described above, it is required to match the timing of the clamp of the work 19 by each electrode, which is realized by the operation of the first balance-like link mechanism 10 and the second balance-like link mechanism 17. There is. The double-head welding gun 1 according to the present embodiment described above requires approximately twice the cross-sectional area of the cylinder 2 and approximately 1.5 times the capacity of the welding transformer 4 as compared with the conventional one-point welding gun. However, it can be kept within the allowable load range of a robot equipped with a conventional one-point welding gun, and work efficiency can be doubled.

[0009]

[Effect of the device]

 As described above, according to the present invention, two piston rods are mounted in parallel on one cylinder, and the movable electrode mounted on the tip of each piston rod is moved forward and backward with respect to the fixed electrode. Even when there is a step difference in the clamp position of the work by the fixed electrode and the fixed electrode, the work is clamped equally by the movable electrode and the fixed electrode. That is, since the pressing force of the piston by the cylinder is applied to the piston rod through the first balance-like link mechanism, even if there is a step at the welding portion where each movable electrode contacts the workpiece, the first balance-like link is produced. The pressing force is evenly applied to each piston rod by the balance pressurization of the mechanism, and each fixed electrode is attached to the work piece by connecting and supporting each yoke to which each fixed electrode is attached by the second balance-like link mechanism. Even if there is a step in the welded portion that abuts against each other, each fixed electrode can be evenly abutted against the work by the balance support of the second balance-like link mechanism. Therefore, the first and second balance-shaped link mechanisms equally pressurize the clamp of the work by each movable electrode and each fixed electrode, and simultaneous energization becomes possible, so that the two points are evenly welded. In addition, with the configuration of the present invention, the increase in the welding gun weight for executing two-point simultaneous welding can be within the allowable load range of the robot equipped with the conventional one-point welding welding gun. A double-headed welding gun that can be mounted is realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a double-headed welding gun according to an embodiment of the present invention.

FIG. 2 is a side view showing the overall configuration of the double-headed welding gun according to the embodiment.

FIG. 3 is a cross-sectional view taken along the line AA of FIG. 1 showing the configuration of a first balance-shaped link mechanism.

FIG. 4 is a sectional view taken along the line BB of FIG. 1 showing the configuration of a second balance-shaped link mechanism.

FIG. 5 is an energization circuit diagram showing energization connection of the double-headed welding gun of the embodiment.

FIG. 6 is a side view showing a schematic configuration of a conventional welding gun.

[Explanation of symbols]

 1 --- Double-headed welding gun 2--Cylinder 5--First yoke 6-Second yoke 9-Piston 10-First balance link mechanism 11-First piston rod 12-First Second piston rod 13 --First movable electrode 14 --Second movable electrode 15 --First fixed electrode 16 --Second fixed electrode 17 --Second balance link mechanism 19 --Work

Claims (1)

[Scope of utility model registration request] 1. A cylinder is provided with two piston rods mounted in parallel, and the two piston rods are reciprocally moved to face the movable electrodes attached to the tips of the piston rods and the movable electrodes. In a double-headed welding gun for clamping and welding a work between a fixed electrode and a fixed electrode, both piston rods and a piston sliding in the cylinder are divided equally into the piston rod and the piston rod. The first balance-like link mechanism to be operated is connected, and the respective yokes to which the respective fixed electrodes are attached are connected and supported to the cylinder by a second balance-like link mechanism provided at a position in the advancing direction of the cylinder. A double-headed welding gun characterized by that.