JPS5848276B2 - spot welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spot welding device, and more particularly to a multi-spot welding device that performs spot welding at multiple points almost simultaneously.

Conventionally, as this type of multi-spot welding device, a plurality of fixed electrodes are provided on a jig stand, a workpiece is placed on the jig stand, and the workpiece is appropriately clamped by a clamping means.
A plurality of welding guns having movable electrodes are provided corresponding to each of the fixed electrodes, and each welding gun is equipped with a welding transformer that supplies power via a power supply cable, and the movable electrode of each welding gun is connected to the corresponding fixed electrode. A welding method is known in which spot welding at multiple points can be performed substantially simultaneously by holding a workpiece between electrodes and applying pressure to the welding gun, as well as supplying power to a welding gun.

However, in the above-mentioned conventional welding gun, each welding gun is independently equipped with a welding transformer and power supply cable, so the number of power supply equipment included in the entire device is enormous (usually 20-30
The problem was that the device became complicated and expensive.

In addition, it is necessary to transport the workpieces in and out using a separate conveyance means, making the device structure even more complicated.

The present invention has been made in view of this point, and includes a plurality of welding guns provided on the jig table side, the workpiece being pressurized by the welding guns, and one power supply equipment for each of the welding guns. By sequentially supplying power to the contacts using a contact gun unit for easy and efficient welding, and by providing the contact gun with the function of carrying out workpieces, the number of power supply equipment to be equipped can be greatly reduced, and another It is an object of the present invention to provide a multi-spot welding device that eliminates the need for a conveying means, thereby simplifying the device and reducing costs.

That is, the present invention provides a welding process in which a plurality of fixed electrodes are provided on a jig stand, and a movable electrode provided on a pressurizing arm is provided around the jig stand so that the fixed electrode can be pressurized by a cylinder. A plurality of guns are arranged, and a power supply terminal is provided on the pressure arm of each welding gun, and a contact gun is provided, which consists of a pair of clamp arms that can be opened and closed by a cylinder, and a contact terminal provided at the opening and closing ends of the clamp arms. ,
A power supply cable from a transformer is connected to the clamp arm of the contact gun, the contact gun is attached to the robot, and a holding part that can hold the workpiece according to the shape of the workpiece and a support part that is clamped by the contact terminal of the contact gun are provided. A conveying tool having the above-mentioned contact gun is detachably attached to the clamp arm of the contact gun, and after placing the work on the jig table, the work is pressurized by the welding gun, and the robot operates to apply pressure to each power supply terminal of the welding gun. The present invention is characterized in that the contact gun is sequentially brought into pressure contact to perform spot welding at multiple points, and then the workpiece is held by the general transport tool and the workpiece is generally moved in and out.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

In Figures 1 to 5, 1 stands for 4 standing on the floor.
It is a gate-shaped housing consisting of book columns 2, 2... and an upper frame 3 fixed to the upper ends of the columns 2, 2..., and a jig stand is provided on the floor of the portal housing 1. 4 is installed, and the jig stand 4 is provided with a plurality of upwardly facing fixed electrodes 5, and the upper end surface of each fixed electrode 5 is formed in a shape that matches the shape of the surface of the welding part of the workpiece W.

A plurality of welding guns 6 are arranged around the jig table 4.

Each welding gun 6 includes a pressure arm 8 rotatably supported on the jig table 4 via a bracket 7, and two movable electrodes 9, for example, protruding from the tip of the pressure arm 8. A piston rod 11 of an air cylinder 10 is connected to the other end of the pressure arm 8, and the operation of the air cylinder 10 moves the movable electrode 9 to the corresponding fixed electrode 5.
The fixed electrode 5 is configured to be opposed to the fixed electrode 5 and can be pressurized freely against the fixed electrode 5.

Further, a power supply terminal 12 is integrally provided on the pressure arm 8 of each of the welding guns 6, and the power supply terminal 12 is connected to the pressure arm 8.
During the pressurizing operation, each power supply terminal 12 is provided so that the height thereof is the same, and two of each power supply terminal 12 are combined into l pairs, and the combined pair of power supply terminals 12.
The distance between the contact guns 12 is the same as the distance l between the contact guns 15, which will be described later.

On the other hand, the upper frame 3 of the gate-shaped housing 1 is provided with a robot 13 that can move up and down, back and forth, and left and right, and a U-shaped support frame 14 is connected to the lower end of the robot 13 at its center. A pair of contact guns 15, 15 are attached to both ends of the support frame 14 with a predetermined distance l between them.

Each of the contact guns 15 includes a pair of clamp arms 17.17 which can be opened and closed by an air cylinder 16, and contact terminals 18.18 formed at the opening and closing ends of the clamp arms 17, 17. 1
One end of a power supply cable 19 is connected to one of the power supply cables 7 and 17, and the other end of the power supply cable 19 is connected to a welding transformer 20 installed on the upper frame 3.
0 by power supply cable 19 and clamp arm 17
Power is supplied to the contact terminals 18 and 18 through the air cylinder 16, and the clamp arms 17 and 17 are opened and closed by the operation of the air cylinder 16, so that the contact terminals 18 and 18 can be connected to the power supply terminal 12 by contact.

Further, reference numeral 21 denotes a conveyance tool detachably provided on the clamp arms 1γ and 17 of the contact gun 15, and the conveyance tool 21 has a lower end as a holding part that corresponds to the shape of the workpiece W and can hold the workpiece W. electromagnet 22.22
and the contact terminals ia, i of the contact gun 15 at the upper end.
After welding, the electromagnet is clamped to the clamp arms 1γ, 17 of the contact gun 15 and connected to the electromagnet by a transformer provided separately from the welding transformer 20 via contact terminals 18 and 18. 2
The electromagnet 22.22 is supplied with clamp power, and the electromagnet 22.22 attracts and holds the welded workpiece W, and the robot 13 takes out the workpiece W from the jig table 4 and transports it to the next process. Welding gun 6 on jig stand 4 during welding
be placed in a position that does not interfere with

Note that 23 is a workpiece installation cylinder for tilting the jig table 4 to facilitate the installation of the workpiece W, and 24 is an insulator interposed between the power supply terminals 1, 2, 1, and 2.

Next, the operation of the above-mentioned embodiment will be explained with reference to the case where a bracket, reinforcement, etc. are welded to the inner back door of an automobile.First, the work-embedding cylinder 23 is operated and the jig table 4 (fixed electrode 5 ) After placing the workpiece W on the
~B4, C1~C4... Each welding gun 6 corresponding to the welding point position indicated by H1~H4 is rotated by the operation of the air cylinder 10, and each movable electrode 9
The workpiece W is held under pressure against the fixed electrode 5.

Here, the power supply terminal 12 of each welding gun 6 rotates together with the pressurizing arm 8, and the distance l between the contact guns 15, 15 is increased.
Pairing power supply terminal 1 standing upright at the same distance away from
A plurality of sets (8 sets in the figure) of 2.12 combinations are formed.

Next, in the state where the workpiece W is pressurized in this way,
The robot 13 is activated and a pair of contact guns 15 are fired.
, 15 are successively opposed to each of the pair of power supply terminals 12, 12, and the clamp arms 17 . 1 Open and close 7 and contact terminal 18
．． 18 to the power supply terminal 12 and supplying power from the welding transformer 20, a large number of dot points A1 to A4 m B1 to B4, C, to C4,...
...H1 to H4 are sequentially spot welded.

After welding the workpiece W, the pressure applied by each welding gun 6 is released, and the conveying tool 21 is moved to the contact gun 15,
15, the electromagnet 22,
22 holds the workpiece W by suction, and the robot 13 removes it from the jig table 4 and transports it to the next process, thereby completing the multi-spot welding process.

In the above embodiment, the robot 13 is equipped with a contact gun 15.
Although a pair of these are provided via the support frame 14, it goes without saying that the number may be increased or decreased to one or three or more depending on the shape and size of the workpiece.

Therefore, according to the present invention, after placing a workpiece on a jig stand, the workpiece is pressurized by a plurality of welding guns provided around the jig stand, and the power supply terminals of the welding guns are connected to each power supply terminal of the welding guns by the operation of the robot. On the other hand, the contact gun is pressed into contact in sequence to perform multi-point spot welding, and then the workpiece is held by a transport tool and the workpiece is unloaded, so there is no need for a large number of power supply equipment as in the past. Multi-spot welding can be performed easily and efficiently using only one power supply equipment and no separate conveyance means, and the structure of multi-spot welding equipment can be simplified and costs can be reduced. This is something that can be automated.

[Brief explanation of drawings]

The drawings illustrate embodiments of the invention, with FIG. 1 being a front view and FIG.
The figure is a plan view, FIG. 3 is a side view, FIGS. 4 and 5 are enlarged front views and side views of essential parts, respectively, and FIG. 6 is an operation diagram. 4... Jig stand, 5... Fixed electrode, 6...
...Welding gun, 8...Pressure arm, 9.
...Movable electrode, 12...Power supply terminal, 13
...Robot, 15...Contact gun, 17...Clamp arm, 18...
・Contact terminal, 19...Power cable, 2
0...Welding transformer, 21...Transportation tool, 22...Electromagnet.

Claims (1)

[Claims] 1 A plurality of fixed electrodes are provided on a jig stand, and a plurality of welding guns are arranged around the jig stand, each of which has a movable electrode provided on a pressurizing arm that can be freely pressurized with a cylinder against the fixed electrode. A power supply terminal is provided on the pressure arm of each of the welding guns, and a contact gun is provided which is made up of a pair of clamp arms that can be opened and closed by a cylinder and a contact terminal provided at the opening and closing ends of the clamp arms. Connect the power supply cable from the transformer to the clamp arm, attach the contact gun to the robot, and
A transfer tool having a holding part that can hold the workpiece according to the shape of the workpiece and a support part that is clamped by the contact terminal of the contact gun is removably attached to the clamp arm of the contact gun, and the workpiece is placed on the jig table. After placing the workpiece, the workpiece is pressurized by the welding gun, and the contact gun is brought into pressure contact with each power supply terminal of the welding gun in sequence by the action of the robot to perform multi-point spot welding.Then, the workpiece is transferred to the above-mentioned transport tool. A spot welding device characterized in that a person holds and carries out a workpiece.