JPS6281276A - Spot welding gun - Google Patents

Abstract

PURPOSE:To cope with a direct welding and indirect welding by one unit of a gun by constituting to connect a pair of electrodes to a pair of output terminals of a transformer and to connect auxiliary electrode to either one part of the output terminals. CONSTITUTION:The electrodes 11, 16 at the tip of each arm 10, 15 are connected to the output terminals 14, 18 of a transformer 13 via cables 12, 17 and an auxiliary electrode 19 is connected to one part of the terminal 18 via a cable 20. A spot welding is made under a current circuit E1 with the electrification by making the electrode 19 in non-contact state by pinching with pressure the flange part F of panels W1, W2 between the electrode 11, 16. The spot welding is made under a current circuit E2 with the electrification by making the electrode 19 in press-fitting state to the panel W2 by pinching with pressure the flange part F between the electrodes 11, 16 together with an insulating type pack electrode 21. Accordingly both direct welding and indirect welding can be coped with one unit of the gun.

Description

[Detailed description of the invention] Industrial applications This invention relates to improvements in spot welding guns.

Problems to be Solved by the Prior Art and the Invention As spot welding methods, there are direct spot welding and indirect spot welding.

In direct spot welding, as shown in Figure 5, welding current is passed from one electrode 1 through the welding point to the other electrode 2.
This is the most basic method.

Furthermore, in indirect spot welding, as shown in Figure 6, the current flowing from one electrode 3 to the welding point passes through a part of the workpiece and flows to the other electrode 4 at a part away from the welding point. Although this method has the disadvantage of ineffective shunting compared to direct welding, it has the advantage that both electrodes 3.4 can be arranged on one side of the workpiece.

5 is a transformer, and 6 is a back electrode.

Since direct spot welding and indirect spot welding as described above are usually performed using a single spot welding gun, for example, direct spot welding and indirect spot welding may be used together in the same process. In this case, two cans must be prepared.

Particularly in the welding process using industrial robots, it is necessary to prepare two robots with separate guns or one robot.
It is necessary to switch between two types of guns each time using the robot on the stand.

Means for Solving the Problems The present invention aims to provide a single spot welding gun that can handle direct spot welding and indirect spot welding. In addition to the pair of electrodes for spot welding, an auxiliary electrode for indirect spot welding is attached, and the pair of electrodes are connected to a pair of output terminals of the transformer, and the auxiliary electrode is connected to one of the pair of output terminals of the transformer. The structure is connected to either one of the two.

Effect: According to the above configuration, direct welding is possible by leaving the auxiliary electrode 19 inoperative as shown in FIG. 2 (At).

Further, as shown in FIG. 2 (Bl), by allowing the auxiliary electrode 19 to function without making the electrode 16 function, and by using the pack electrode 21 in combination, indirect welding becomes possible.

Embodiment FIG. 1 is a diagram showing a more specific embodiment of the present invention, and shows a so-called X-shaped spot welding gun of the hinge opening/closing type.

As shown in FIG. 1, an electrode (chip) 11 attached to one arm 10 is connected to the positive output terminal 14 of one transformer 13 via a cable 12, and
Electrodes attached to the other arm 15 (1,000'7))
16 is connected to the negative output terminal 18 of the transformer 13 via a cable 17. In addition to the above pair of electrodes 11 and 16, an auxiliary electrode 19 is added,
]This auxiliary electrode 19 is connected to the transformer 1 via the cable 20.
It is connected to the negative side output terminal 18 of No. 3.

Therefore, the spot welding gun described above can be used for direct spot welding and indirect spot welding, as shown in FIGS. 2(A) and 2(B).

For example, when welding an automobile door panel by direct spot welding, as shown in FIG. ,
The auxiliary electrode 19 is placed in a non-contact manner with respect to the outer panel W and the inner panel W.

By applying current in this state, spot welding is performed along the current path shown by arrow E.

Further, when welding is performed by indirect welding, a pack electrode 21 is used in addition to the auxiliary electrode 19. More specifically, as shown in FIG. 2(B), the hemming flange portions F1 of the outer panel WI and the inner panel Wt are pressurized and clamped together with the pack electrode 21 by the electrodes 11 and 16, and the auxiliary electrode 19 is attached to the inner panel W.

Place it in pressure contact with the An insulator 22 is interposed in the middle of the pack electrode 21, and the electrode 16, the outer panel W, and the inner panel W! There is insulation between the two. By applying electricity in this state, spot welding is performed along the current path shown by the arrow.

Here, in performing the above-mentioned indirect welding, the jigs shown in FIGS. 3 and 4 are used.

That is, the pack electrode 21 described above is disposed via the bracket 24 on the jig base n where the door panel W as the workpiece is positioned, while the swing arm 26 supported by the bracket 25 on the jig base n , the aforementioned auxiliary electrode 19 is disposed via the mounting plate 27. The electrode plate 211L of the pack electrode 21 includes, in addition to the insulator 22, an insulating collar 28 and insulating plates 29, 30.
It is insulated from the bracket 24 by.

In addition to switching between direct welding and indirect welding as described above, the swing arm 26 is rotated by the air cylinder 31, and in the case of direct welding, the swing arm 26 is moved to the upper limit position Q+ in FIG.
The swing arm 26 is held at the lower limit positions Q and V only during indirect welding. 32
is a buffer spring. In other words, by bringing the auxiliary electrode 19 into pressure contact with the inner panel W during indirect welding, the auxiliary electrode W and the pack electrode 2
Spot welding is performed using 1 as a medium.

Effects of the Invention According to the present invention, in addition to the pair of electrodes connected to the transformer by cable, another auxiliary electrode is added.
One gun can handle both direct welding and indirect welding, making it unnecessary to prepare two robots or switch guns, especially in robot welding processes.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and FIG. 2 (Al
, (Bl is an explanatory diagram of the operation of the spot welding gun in Figure 1, Figure 3 is an explanatory diagram of a jig used in combination with the spot welding gun, Figure 4 is a view taken in the direction of arrow A in Figure 3, and Figure 5 is an explanatory diagram of the operation of the spot welding gun in Figure 1. The figure is a conceptual diagram of conventional direct welding, and Fig. 6 is a conceptual diagram of indirect welding. 10, 15... Arm, 11, 16... Electrode,
12, 17, 20...cable, 13...transformer, 14, 18...output terminal, 19...auxiliary electrode. Outside 2 people 1st Figure 10.15-111 Arm 11.16--Electrode 12.17.20--Boot 1 Le 13--1 Tone 14.18--1 Output Mizuko 19-1 11 Auxiliary electrode

Claims (1)

[Claims] (1) In addition to a pair of electrodes for direct spot welding, an auxiliary electrode for indirect spot welding is attached, and the pair of electrodes are connected to a pair of output terminals of a transformer, and the auxiliary electrode is connected to a pair of output terminals of a transformer. A spot welding gun characterized in that it is connected to either one of the output terminals.