JP3219597B2 - Multi spot welding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-spot welding machine used in a process of assembling an automobile body, and more particularly to a multi-spot welding machine capable of setting a high density of a plurality of stud guns.

[0002]

2. Description of the Related Art As shown in FIG. 2, a conventional multi-spot welding machine has a plurality of stud guns (1), (1)... Arranged in parallel, and a power supply cable (2) for each stud gun (1). Air supply hose for lower and upper electrodes (3)
(4) The cooling water hoses (5) and (6) are connected.

The stud gun (1) is provided with an air cylinder device (7) as a driving source for applying a downward movement stroke and an upward movement stroke to the movable electrode (9), and the movable electrode (7) is provided at the tip of a piston rod (8). As the fixed support means of 9), an insulating joint (10) is mounted.

The fixed electrode (11) is provided facing the movable electrode (9) of each stud gun (1) at a predetermined distance below the movable electrode (9). A seating portion for mounting the welded portion of (12) is formed.

The fixed electrode (11) and the movable electrode (9) are electrically connected via an AC (or DC) welding power source E. That is, the movable electrode (9) and the power source E
A fixed base (13) having a fixed electrode (11) aligned on the upper surface and a power supply E are connected to the power supply cable via a power supply cable (2) which has a large diameter to allow a large current to flow therethrough and therefore is not easily bent. And are connected by a similar power supply cable (14).

In the welding by such a multi-spot welding machine, after the work (12) is positioned and fixed on the fixed electrode (11), the movable electrode (9) and the fixed electrode are connected via the power supply cables (2) and (14). The voltage from the power supply E is supplied to (11). At this time, when the movable electrodes (9) of the two stud guns (1) are simultaneously pressed against the work (12),
Since the imbalance of welding current at two welding points and the variation of welding quality occur, the movable electrode (9) is
The workpieces (12) are pressure-bonded in sequence with the time being shifted one by one.

[0007]

In the conventional multi-spot welding machine (15) shown in FIG. 2, for each stud gun (1), a power supply cable (2) having a relatively large diameter and a high rigidity which is hardly bent. , Air supply hoses (3) and (4) and cooling water hoses (5) and (6). In particular, the power supply cables (2) and (14) are thick and have high rigidity so that they are not easily bent. If the stud guns (1) are closely spaced, it is difficult to route them to the stud guns (1). In addition, it is necessary to secure a space for routing the power supply cable (2), the air supply hoses (3) (4), and the cooling water hoses (5) (6). Therefore, stud gun (1) (1)
.. Must be provided with a considerable interval, and high-density design of a multi-spot hitting pattern is impossible.

Therefore, in order to pressurize a plurality of spot welding spots approaching each other, it is necessary to shift the stud gun (1) or the work (12) two or more times to shift the welding position. The efficiency of welding work was poor.

An object of the present invention is to provide a multi-spot welding machine capable of forming a high-density multi-spot hitting pattern without shifting a stud gun and a work.

[0010]

According to the present invention, there is provided a multi-spot welding machine comprising: a plurality of stud guns having movable electrodes movable up and down; A plurality of fixed electrodes are disposed below the stud gun so as to face the movable electrode in the vertical direction, and the movable electrodes are sequentially driven to be welded on the workpiece positioned on the fixed electrode. In a multi-spot welding machine where each of the movable electrodes of multiple stud guns is connected by a flexible cable and the drive system of each movable electrode is unified, all movable electrodes can be moved up and down at the same time A plurality of conductive booth bars electrically connected to a fixed electrode and a welding power source via a welding power source are arranged on the work so as to be laterally movable and insulated from the work. The booth bar is moved laterally to a position where it does not interfere with the downward movement of the corresponding movable electrode, and at other places, the movable electrode corresponding to the booth bar is abutted to prevent the downward movement of the movable electrode, and the movable electrode and the booth bar are moved. Electrical connection was made to close the welding circuit.

Further, in the multi-spot welding machine, the drive system of the movable electrode is constituted by a double-acting air cylinder, and a lower-moving air supply hose connected to the double-acting air cylinder; The supply hoses are connected by a common header hose, the piston rod of the double-acting air cylinder and the movable electrode are connected by an insulating joint, and the insulating joints are connected in series by a cooling water hose. can do.

[0012]

[Action] The booth bar at the position to be welded on the workpiece in which the welding order has arrived is retracted to a position where it does not hinder the downward movement of the corresponding movable electrode, while at other points, the downward movement of the booth bar is performed. Put it in a position to block,
In this state, compressed air is supplied to the downward movement air supply hose to move all movable electrodes simultaneously. Except for the position where the welding order has arrived, the movable electrode abuts on the booth bar before the movable electrode reaches the workpiece, and the movable electrode and the power supply are conducted. On the other hand, since the booth bar is retracted at a position where the welding order has arrived so as not to obstruct the downward movement of the corresponding movable electrode, the movable electrode is pressed against the work. As a result, a power supply, a booth bar, a movable electrode (a place other than the welding order), a flexible cable, a movable electrode (a place at the welding order), a work, a fixed electrode, and a closed welding circuit of a power supply are formed. Spot welding is performed at the electrode pressure welding point.

Since the movable electrodes are not individually connected to the power supply by the conventional high-rigidity power supply cable but are connected to each other by the flexible cable, the movable electrodes are densely arranged. Easy to set up. In addition, by connecting the upper and lower moving air supply hoses with a common header hose, and connecting the insulating joints supporting the movable electrodes with serial cooling water hoses, the hoses do not become bulky between the stud guns. Therefore, it is possible to arrange the movable electrodes at a higher density.

[0014]

An embodiment of the present invention will be described below with reference to FIG. In the following description, the same components as those in FIG. 2 showing the prior art are denoted by the same reference numerals in principle, and the description of the same items will not be repeated.

The multi-spot welding machine (2) according to the present invention
0) uses a plurality of stud guns (1A) (1B) arranged in parallel, for example, two as a set. Each movable electrode (9A) (9) of the stud gun (1A) (1B)
B) are connected by a flexible cable (21) formed by laminating a thin conductive metal film, for example, a copper film in multiple layers. This flexible cable is also called a shunt. The shunt (21) is a movable electrode (9A) (9
Even if B) is relatively displaced up and down, only the U-shaped bending position is slightly changed, and the shunt (21) itself does not receive any excessive force.

The movable electrodes (9A) and (9A) are separated from the upper surface of the work (12) placed on the fixed electrodes (11A) and (11B) by a slight gap, that is, insulated from the work (12).
B) and an arrangement number (one in this embodiment) smaller than the number of opposed arrangements (two in this specific example) of the fixed electrodes (11A) and (11B) by a good conductive material such as copper. Booth bar (22) is provided. This booth bar (22) is provided with movable electrodes (9A) (9
B) and the fixed electrodes (11A) (11B) are supported so as to be able to move laterally according to a change in the welding position.

The fixed electrodes (11A) and (11B) are fixedly provided on a fixed base (13) made of a conductive material such as copper. The fixed base (13) is connected to one terminal of a power supply E via a power supply cable (23), and the other terminal of the power supply E is connected to a booth bar (22) via a power supply cable (24). .

The work (12) and the booth bar (22) are only required to be electrically insulated. In addition to floating the booth bar (22) from the work (12), an insulating coating (25) is formed on the lower surface of the booth bar (22). The booth bar (2
2) may be brought into contact with the work (12).

Each pair of stud guns (1A) and (1B) whose axes are parallel has an air cylinder device (7A) (7B) for vertically driving the movable electrodes (9A) (9B). These air cylinder devices (7A) (7
B) is composed of a double-acting air cylinder, and a down-moving air supply hose connected to the air cylinder for moving down the movable electrodes (9A) and (9B) is integrated into one header hose (27). In the same manner, the air supply hose for upward movement is integrated into one header hose (26). The piston rod (8) of the air cylinder device (7A) (7B)
A) and (8B) are connected to the movable electrodes (9A) and (9B) via insulating joints (10A) and (10B). These insulating joints (10A) and (10B) are connected to each other by a cooling water hose (28B), and one of the insulating joints (10A)
Is connected to a water supply hose (28A), and the other insulating joint (10B) is connected to a drainage hose (28C).

Cooling water hose (28A) (28B) (28C) Multi-spot welding machine (20) configured as above
Will be described in the following order. In the present embodiment, first, the work (12) is spot-welded between the second movable electrode (9B) and the second fixed electrode (11B).
Next, the first movable electrode (9A) and the first fixed electrode (11
The step of spot welding the work (12) during A) will be described.

A booth bar (2) is provided on the upper surface of the work (12) located below the second stud gun (1B) at the initial welding position, that is, above the second fixed electrode (11B).
2) Without placing, the booth bar (22) above the work (12) located below the first stud gun (1A) at the next welding point, that is, above the first fixed electrode (11A).
Is moved. Cooling water hose (28A) (28
B) Insulation joint (10A) (10B) via (28C)
Cooling water is constantly supplied to the inside and the first and second movable electrodes (9A) and (9B).

In this state, compressed air is introduced from the header hose (27) common to the air cylinder devices (7A) and (7B), and the first stud gun (1A) and the second stud gun (1B) are simultaneously operated. When it is moved down, the lower end of the first movable electrode (9A) comes into contact with the upper surface of the booth bar (22) at a place where the welding order has not arrived. The first movable electrode (9
A) Even after the downward movement is stopped, the second movable electrode (9B) continues to descend, and its lower end is brought into contact with the upper surface of the work (12). As a result, the second fixed electrode (11B)-fixed base (13)-power supply cable (23)-DC power supply E-power supply cable (24)-booth bar (22)-first movable electrode (9A)-shunt ( 21) -Second movable electrode (9B)
-A work (12)-a closed circuit of the second fixed electrode (11B) is formed. When a current flows from the power supply E to the closed circuit, the work (12) held in a pressurized state between the second movable electrode (9B) and the second fixed electrode (11B) located immediately below the second movable electrode (9B). ) Is spot welded.

After the first spot welding is completed, the air inflow path to the air cylinder devices (7A) (7B) is switched from the hose (27) to the hose (26), and the stud guns (1A) (1B) Is raised once. Next, the booth bar (22) is laterally moved from directly below the first movable electrode (9A) to directly below the second movable electrode (9B), and the first movable electrode (9A) and the first fixed electrode (11A) are moved. And the same welding operation is repeated.

In this embodiment, two stud guns (1
A) Multi-spot welding machine (2)
Although 0) was used, three or more stud guns can be used as one set. When a set of three stud guns is used, the number of the booth bars (22) that perform the shift operation is two, and a closed circuit is formed between the remaining set of movable electrodes and the fixed electrodes where the boot bar (22) is not provided. Thereby, the work (12) is spot-welded. Practically, a pair of stud guns is used as one unit, and a plurality of units, for example, arranged vertically and horizontally adjacent to each other in a matrix, and the work (12) is welded at multiple points at narrow intervals.

The present invention can also have the following configuration other than the first aspect.

The drive system for the movable electrode is constituted by a double-acting air cylinder, and the lower-moving air supply hose and the upper-moving air supply hose connected to the double-acting air cylinder are common to each other. A communication is made by a header hose, the piston rod of the double-acting air cylinder and the movable electrode are connected by an insulating joint, and the insulating joints are connected in series by a flexible cooling water hose. 1
The multi-spot welder as described.

[0027]

As described above, according to the present invention, the movable electrodes of adjacent stud guns are electrically connected to each other by a flexible cable, and one movable electrode is brought into contact with a booth bar connected to a power source, and the other movable electrode is contacted. Current is supplied via a flexible cable to each of the movable electrodes, so that it is not necessary to connect a large-diameter, high-rigidity, and hard-to-bend power supply cable to each movable electrode as in the related art. Therefore, it is not necessary to secure a space allowance for routing the power supply cable, so that the distance between the stud guns can be narrowed, and high-density multi-spot welding can be performed. Further, by unifying the drive system of the movable electrode with, for example, a header hose or connecting the cooling water hose in series, it is possible to further arrange the movable electrodes with high density.

[Brief description of the drawings]

FIG. 1A is a perspective view of a multi-spot welding machine according to the present invention, and FIG. 1B is a partial front view of the welding machine.

FIG. 2 is a perspective view of a conventional multi-spot welding machine.

[Explanation of symbols]

 1A 1st stud gun 1B 2nd stud gun 7A 1st air cylinder device 7B 2nd air cylinder device 9A 1st movable electrode 9B 2nd movable electrode 10A 1st insulating joint 10B 2nd insulating joint 11A First fixed electrode 11B Second fixed electrode 12 Work 13 Fixed base 20 Multi spot welder 21 Shunt (flexible cable) 22 Booth bar 23 Power supply cable 24 Power supply cable 26 Header hose 27 Header hose 28A Cooling water hose 28B Cooling Water hose 28C Cooling water hose E Power supply for welding

Claims (1)

(57) [Claims] 1. A plurality of stud guns having movable electrodes which can move up and down are arranged side by side, and a plurality of fixed electrodes which are respectively opposed to the movable electrodes in a vertical direction are arranged below these stud guns. In a multi-spot welding machine in which the movable electrodes are sequentially driven and the positions to be welded of the work positioned on the fixed electrode are welded one by one, the movable electrodes of the plurality of stud guns are electrically connected by a flexible cable. In addition, the drive system of each movable electrode is unified to enable all movable electrodes to move up and down at the same time, and a plurality of conductive booth bars electrically connected to the fixed electrode via a welding power source are provided on the work. Disposed laterally and insulated from the work, the booth bar at the point where the welding order has arrived is moved laterally to a position where it does not hinder the downward movement of the corresponding movable electrode,
A multi-spot welding machine in which a movable electrode is brought into contact with the booth bar at other locations to prevent the corresponding movable electrode from moving downward, and the welding electrode is closed by electrically connecting the movable electrode to the booth bar.