JPH0360875A - Spot welding equipment - Google Patents

Abstract

PURPOSE:To reduce the cost of the spot welding equipment and to simplify its constitution by operating selectively plural spot welding guns by using a common control means. CONSTITUTION:Pressurizing cylinders 12 of the spot welding guns 10A and 10B are connected with a pressure source 40 via solenoid valves 30A and 30B. Primary winding l1 of a transformer 50A is connected with a power source 70 via a switch circuit 60 and primary winding l1 of a transformer 50B is connected in parallel with the primary wiring l1 of the transformer 50A. In addition, secondary winding l2 of the transformers 50A and 50B are connected with electrode chips 11 and 11 of the welding guns 10A and 10B, respectively. The switch circuit 60 is provided with two thyristors 61 and 62 whose gates are connected with a timer contactor 80. When a robot controller 90 then adds a valve driving signal and a valve selecting signal to the timer contactor, the two spot welding guns 10A and 10B operate selectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spot welding device that selectively uses a plurality of spot welding guns.

[Conventional technology]

A welding gun of a spot welding machine includes a pair of electrode tips and a pressure cylinder for pressing the electrode tips into contact with a workpiece.

This welding gun also uses a welding transformer, the primary winding of this welding transformer is connected to a power source via a switch element such as a thyristor, and the secondary winding is connected to the electrode tip.

The pressurizing cylinder is connected to a pressure source via an electromagnetic valve, and is pressurized by operating the electromagnetic valve in response to a valve actuation signal output from a control means such as a timer contact.

The control means outputs a valve actuation signal and then supplies a switch actuation signal to the switch element for a predetermined period of time, and as a result, the switch element is closed for the predetermined period of time, and a welding current is applied between the electrode tips. flows.

[Problem to be solved by the invention]

By the way, in a spot welding device such as a welding robot equipped with a spot welding gun, a welding gun with specifications suitable for the shape and material of the target workpiece is selected and used from a plurality of spot welding guns prepared in advance. There is.

In such conventional welding machines, each spot welding gun is provided with a control means such as the above-mentioned timer contacts, so that the cost is high and the structure is complicated.

In view of this situation, an object of the present invention is to provide a spot welding device that can reduce costs, simplify the structure, and downsize.

[Means to solve the problem]

The present invention provides a spot welding device that selectively uses a plurality of spot welding guns, including a plurality of welding transformers whose secondary windings are connected to each of the welding guns, and whose primary windings are connected in parallel to each other; Means is provided for supplying power to the connected primary windings and selectively operating the pressurizing cylinders of each of the spot welding guns.

[Effect]

In this spot welding device, each spot welding gun is controlled by a common control means.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 conceptually shows an embodiment of a spot welding machine according to the present invention.

The spot welding guns IOA and 10B shown in the figure are 1
A pair of electrode tips 11.11 and this electrode tip 11.1
The workpiece 20 is provided with a pressurizing cylinder 12 that urges the workpieces 1 in a direction toward each other and presses the workpieces 20 into contact with the workpiece 20.

The pressure cylinder 12 of the spot welding gun 10A is connected to the spot welding gun IOB via the electrode valve 30A.
The pressurized cylinders 12 are each connected to a pressure source (in this embodiment, a pneumatic source) 40 via an electromagnetic valve 30B.

Further, dedicated welding transformers 50A and 50B are integrally attached to each of the spot welding guns IOA and 10B, respectively.

The primary winding tllJl+ of the transformer 5OA is connected to a commercial power supply 70 via a switch circuit 60.
The primary winding J11 of 0B is the primary winding Jl of the transformer 50A.
+ is connected in parallel. Further, secondary windings J2 of transformers 50A and 50B are connected to electrode tip 11.11 of welding gun 5OA and electrode tip 11.11 of welding gun 50B, respectively.

The switch circuit 60 includes two circuits 61 and 62 that are connected in parallel in opposite directions and have their respective gates connected to the timer contactor 80.

The operation of this embodiment will be explained below.

Now, a welding gun I is attached to the wrist of a welding robot (not shown).
Assuming that the OA and welding transformer 50A are attached, the welding gun 10A is moved to the welding site of the workpiece 20 under the position control of the welding robot by the robot controller 90.

The robot controller 90 recognizes that the welding gun IOA is currently attached to the robot based on an operator's instruction or a discrimination signal from a welding gun automatic discrimination means provided at the robot's wrist or the like. Therefore,
At time t1 shown in FIG. 2(a), the valve drive signal shown in FIG. 2(a) and a valve selection signal (not shown) for commanding the valve 30A are applied to the timer contactor 8o, respectively.

The timer contactor 80 provides the valve drive signal to the valve 30A based on the valve selection signal, thereby energizing the valve 30A.

As a result, the pressure cylinder of the welding gun IOA is operated to extend, and the workpiece 20 is clamped by the welding tip 11.11 of the connecting gun IOA.

Next, the robot controller 9o sends the welding start command signal shown in FIG. 2(b) to the timer contactor 8 at time t2.
Add to 0.

The timer contactor 80 has a built-in timer (not shown), and the command pulse signal activates this timer. As a result, the timer outputs a gate signal having a time width t2 to t3 as shown in FIG. 2(c), and this signal is transmitted to each thyristor 61 .
62 gates respectively.

When a gate signal is given to the thyristors 61.62, those thyristors 61.62 are fired, so that a welding current flows between the tips 11.1.1 of the welding gun IOA, and as a result, spot welding is performed on the workpiece 20. will be performed.

Note that the other welding gun 1. OB is the pressure cylinder 12
is in a non-operating state, there is a wide gap between the welding tips 11 and 11, and therefore no welding current flows.

When the timer of the timer contactor 80 times up, the gate signal turns OFF at time t1 shown in FIG. 2(c).
As a result, the welding current flowing to the welding gun IOA is stopped.

On the other hand, the timer contactor 80 sends a signal indicating the time-up to the robot controller 90. Based on this, the robot controller 90 turns off the valve drive signal as shown in FIG. be separated. From now on, welding gun I
After the OA is moved to the next welding point by the robot, it performs the same welding operation as above.

When the other welding gun IOB is used in place of the welding gun 10A to change the specifications of the workpiece 20, those welding guns are replaced by an automatic welding gun replacement device (not shown) or by manual operation. .

Even when the welding gun IOB is in use, the timer contactor 80 outputs valve drive signals and gate signals as illustrated in FIGS. 2(a) and 2(b). At this time, a valve drive signal is given to the electromagnetic valve 30B based on the output signal of the automatic welding gun discriminator, etc., so that the welding gun 10B performs spot welding.
Thus, according to this embodiment, one timer contactor 80 is used for two spot welding guns 10A.

10B can be selectively activated. Note that the set time of the timer shown in FIG. 2(c) can also be changed depending on the welding gun used.

Further, in the above embodiment, there are two welding guns 10A.

Although welding guns 10B are selectively used, the present invention can of course be applied to cases where three or more welding guns are selectively used.

〔Effect of the invention〕

According to the present invention, a plurality of spot welding guns can be selectively operated using a common control means. Therefore, costs can be reduced compared to conventional spot welding devices, and the configuration can be simplified and downsized.

[Brief Description of the Drawings] Fig. 1 is a block diagram conceptually showing an embodiment of a spot welding gun according to the present invention, and Fig. 2 is a timing chart for explaining the operation of this embodiment. be. 10A, 1. OB...Spot melting (concubine gun, 11.1
1... Electrode tip, 12... Pressure cylinder, 20...
...Work, 30A, 30B... Electrode bulb, 50A
, 5Q13... Welding transformer, 60... Switch circuit, 70... Power supply, 80... Timer contactor, 9
o...Robot controller applicant Suzuki Motor Co., Ltd.

Claims (1)

[Scope of Claims] A spot welding device that selectively uses a plurality of spot welding guns, comprising a plurality of welding transformers each having a secondary winding connected to each of the welding guns, and a primary winding connected in parallel to each other; A spot welding apparatus comprising means for supplying power to the parallel-connected primary windings and selectively operating pressure cylinders of each of the spot welding guns.