JPH06328267A - Electrode positioning device for robot gun - Google Patents

Abstract

PURPOSE:To control positioning of an electrode of the robot gun by an electric actuator by providing the electric actuator on an equalizing device and regulating the electrode moving quantity at the gun arm side continuously. CONSTITUTION:The whole gun is lifted up by operating the electric actuator 13 and a fixed side electrode 6 is brought close to or abutted on the specified work position and stopped almost simultaneously with a movable side electrode 4 at the rod side by operation of a pressure device 3. When the whole gun is lifted up, the fixed side electrode 6 at the gun arm side is followed up from the lower side of works by compression of a spring S. While backing up by the fixed side electrode 6, welding pressure is applied to the movable side electrode 4 by operation of the pressure device 3 which is energized to perform pressure welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode positioning device for a robot gun.

[0002]

2. Description of the Related Art Conventionally, when a spot welding gun is attached to an automatic machine such as an industrial robot to perform welding, generally, a C type multi-stage robot gun has an electrode positioning cylinder attached to an equalizer. There is. In this case, when the gun is opened, air is supplied to the positioning cylinder to hold the weight of the gun, and the electrode on the gun arm side moves so as to stop with a slight gap from the work (workpiece),
The arm side electrode grips the work by the force of the spring by the air exhaust of the cylinder, that is, the gun arm side electrode, that is, the fixed side electrode, is pressed by the spring force that balances the gun weight, and precedes the rod side electrode, that is, the movable side electrode. Then, the work is abutted against the work to prevent the work from being deformed due to the inertial force of the movable side electrode, and then, after welding, the positioning cylinder operates to release the fixed side electrode simultaneously with the opening of the movable side electrode. is there.

[0003]

Conventionally, in the electrode positioning device of this type, a pressurizing and releasing signal is often sent directly from the robot controller to the gun. In that case, a signal is sent to the switching valve of the positioning cylinder. There is a problem in that the welding spot speed is delayed because an operation time of detouring to the air path of switching the valve to supply and exhaust air by switching the valve is provided.

Further, conventionally, when the amount of change in the spring force for balancing the weight of the gun becomes large and the posture of the gun in the gravity direction changes to different colors depending on the hitting position, it becomes difficult to balance the weight. There is a problem of deforming the hood. That is, it takes time to discharge air from the positioning cylinder, and the work may be deformed due to the strength relationship between the positioning spring and the work. In other words, the operation by the conventional equalize method is
As shown in Fig. 6, the fixed side electrode and the movable side electrode are opened as shown in the figure, moved to the welding spot position, and moved as shown in FIG. Let Therefore,
As the electrode on the rod side rises, the distance from the work increases, and the extra stroke (h) increases, which causes the welding point speed to be delayed, which results in lost time.

Although the electrode opening operation after completion of welding is omitted in the drawing, after the movable side electrode is released from the work, the fixed side electrode is returned to the original state in which the entire gun is operated by the positioning cylinder of the equalizer. Open. Therefore, the delay problem of the opening operation cannot be ignored.

[0006]

Therefore, in the present invention, a C type spot welding gun having an electrode operated by a pressurizing device and an electrode provided on the gun arm side is used for an industrial robot via an equalizing device. In the device for pressure welding while guiding the gun to the welding welding position of the work according to the program operation of the robot, an electric actuator is provided in the equalizing device, and an electrode on the gun arm side is provided by the electric actuator. Provided is an electrode movement positioning device for a robot gun whose main feature is to regulate the amount of movement of the electrode infinitely.

Another aspect of the present invention is an X-type spot welding gun in which two gun arms rotatably supported by a gun support bracket via hinges are opened and closed by a pressurizing device. There is provided an electrode positioning device for a robot gun, which is provided with an electric actuator for steplessly regulating the movement amount of the electrode.

[0008]

[Operation] Therefore, according to the present invention, in the C-type robot gun, the movement amount of the electrode on the gun arm side is regulated steplessly by the electric actuator provided in the equalizing device, so that as shown in FIG. The electrode on the gun arm side and the electrode on the movable side are automatically lapped by the electrode pressurization / release operation of the welding gun and the movement of an automatic device such as a robot, and the movable side electrode and the fixed side electrode are placed from before the welding point position. It is possible to approach or contact the work piece at the same time. Also, the electrode opening operation after welding can be performed almost at the same time by wrapping it with the robot operation. As a result, the operation time of FIG. 6 by the positioning cylinder of the conventional equalizer can be omitted, and the production cycle time in the automatic welding line can be shortened, that is, the continuous welding speed can be dramatically increased.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram in which the present invention is applied to a C type robot gun. FIG. 2 is a sectional view showing an embodiment of the electrode positioning device according to the present invention. FIG. 3 is a sectional view showing another embodiment of the electrode positioning device according to the present invention. FIG. 4 is a schematic diagram when the present invention is applied to an X type robot gun.

In FIG. 1, reference numeral 1 denotes a robot gun.
Reference numeral 2 is a gun arm fixed to the main body frame 20, and 3 is a pressurizing device, which is a drive source for pressurizing electrodes such as an air cylinder or an electric motor. Reference numeral 4 denotes a movable side electrode that moves forward and backward by an actuating shaft 5 of the pressurizing device. Reference numeral 6 denotes a fixed side electrode fixed to the tip of the gun arm.

Reference numeral 7 denotes an equalizer, which is shown in detail in FIG. 2, for example, two guide plates 11 provided between two support plates 9 and 10 fixed to a gun support bracket 8 at appropriate intervals. And the guide member 12 is fixed,
The body frame 20 slides on the gand members 11 and 12. An electric actuator 13 is, for example, an electric motor, which is fixed to the support plate 10, and the pressing plate 15 of the body frame 20 is moved along the guide members 11 and 12 by the ball screw 14 of the motor. Reference numeral 16 is an electric actuator for adjusting the set pressure of the weight balance, which moves the pressing plate 19 by rotating the ball screw 18 of the motor fixed to the support plate 9, and moves between the pressing plate 19 of the main body frame 20 and the pressing plate 19. The set pressure of the spring S inserted in the is adjustable steplessly. Therefore, it is possible to automatically control the balance force according to the direction and orientation of the gun.

FIG. 3 shows another example of the equalizer. In this example, the positioning motor 13 is directly connected to the main body frame 20.
Is to move. In this case, the rotation of the ball screw 14 of the motor is controlled by the body frame 20 without using the pressing plate 15.
The entire gun can be linearly moved in the direction of the guide member via the nut N fixed to the. The elastic member inserted between the support plate 9 of the equalizer 7 and the body frame 20 and the spring S generate a pressing force in the direction of lifting the gun body to balance the weight of the gun body.

Next, FIG. 4 shows an example in which the present invention is applied to an X gun. In this case, two gun arms 21 and 22 which are rotatably supported by a fulcrum 0, a pair of electrodes 23 fixed to the tips of the gun arms 21 and 22 and An electrode 24 and a pressurizing device 3 for generating a pressing force required for welding are provided between the electrodes 24.

As the pressurizing device 3, one gun arm 2 is provided.
The motor is attached to 2. The output shaft of this motor is
The ball screw 25 is connected, and the ball screw 25 is assembled in the screw hole of the screw nut 26 attached to the other gun arm 21. Between the one gun arm 22 and the gun support bracket 8, a spring S, for example, is inserted into a guide member as an elastic member for setting the balance force, as shown in FIGS. 2 and 3, and this spring is attached to the gun support bracket 8. The fixed motor 27 rotates the ball screw 28 and moves the pressing plate 29 forward and backward to adjust the balance force of the gun weight, and compresses the spring to follow up in the direction of the movable electrode. In this case, between the other gun arm and the gun support bracket 8, for example, a spring S is inserted into the guide member as an elastic member for urging the setting pressure for positioning, and the spring S is fixed to the gun support bracket 8. The pressing plate 31 is moved forward and backward by 30 to control the positioning of the movable side electrode steplessly via the elastic member.

Next, the operation of the present invention will be described with reference to the C gun of FIG. At the welding point, the movable side electrode 4 and the fixed side electrode 6 are opened while the entire gun receives the pressing force of the spring S, and the work is inserted between them.

By operating the electric actuator 13, the whole gun is lifted, and the fixed side electrode 6 is moved to the pressurizing device 3.
By this operation, the movable side electrode 4 on the rod side is approached or brought into contact with a predetermined work position almost at the same time and stopped.

In this case, when the entire gun is lifted,
The compression of the spring S causes the fixed side electrode 6 on the gun arm side to follow up from the lower side of the work. That is, since the fixed side electrode 6 hooks the work from the bottom of the gun arm itself, the spring S contracts without further lifting.

The movable side electrode 4 is backed up by the fixed side electrode 6 and a pressure is applied to the movable side electrode 4 by the operation of the pressurizing device 3 to energize the movable side electrode 4 for pressure welding. At the time of welding, the present invention follows the above-mentioned follow-up by an electric actuator 13 such as an electric motor or an electromagnetic solenoid provided in the equalizing device 7, but the above-mentioned actuator is kept until it goes under the work. 1
3 is used to lock the spring force to fix the electrode on the gun arm side, and when the lock is released together with the pressurizing signal, the pressing force of the spring S moves the entire gun to equalize the pressing force. By doing so, welding can be performed without applying a load to the work.

[0019]

As described above, according to the apparatus of the present invention, when welding is performed by using the robot gun, the fixed side electrode of the spot welding gun precedes the movable side electrode by the work. An electrical actuator to contact or approach the
The actuator can easily position the fixed electrode. In other words, the fixed electrode is lifted up and backed up, and then the movable electrode is contacted and pressure welded. Therefore, a positioning cylinder is not needed, and a switching valve is operated to switch air supply or exhaust air to bypass the waste. Time runs out and the continuous RBI speed increases.
In addition, there is no shock when the positioning cylinder pressurizes / releases, and there is no waiting time until the exhaust of the positioning cylinder is exhausted. Since the work can be brought into contact with or brought close to the work and can be operated simultaneously when the electrode is opened, the welding tact can be drastically shortened by keeping the equalization amount as small as necessary.

In the present invention, the provision of the electric actuator for adjusting the balance setting pressure facilitates the adjustment of the weight balance force of the elastic member for equalizing as in the past, and relates to the posture change in all directions. Can be welded without.

[Brief description of drawings]

FIG. 1 is a side view when the device of the present invention is applied to an equalizing device for a C type robot gun.

FIG. 2 is a cross-sectional view when the device of the present invention is used for an equalizing device.

FIG. 3 is a sectional view showing another embodiment of the device of the present invention.

FIG. 4 is a side view when the device of the present invention is applied to an X type robot gun.

FIG. 5 is an explanatory diagram of the operation of electrodes by a conventional equalizer.

FIG. 6 is an explanatory diagram of the operation of the electrodes by the equalizer device of the device of the present invention.

[Explanation of symbols]

 1 Robot Gun 2 Gun Arm 3 Pressurizer 4 Movable Side Electrode 6 Fixed Side Electrode 7 Equalizer 8 Gun Support Bracket 13 Electric Actuator (for Electrode Positioning) 16 Electric Actuator (for Balance Force Adjustment) S Spring

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[Procedure amendment]

[Submission date] August 27, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

FIG. 5 is an explanatory diagram of the operation of the electrodes by the equalizer of the device of the present invention.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

FIG. 6 is an explanatory diagram of the operation of electrodes by a conventional equalizing device.

Claims (5)

[Claims] 1. A C-type spot welding gun having an electrode operated by a pressurizing device and an electrode provided on a gun arm side is mounted on an industrial robot via an equalizing device, and according to a program operation of the robot. In a device for performing pressure welding while guiding the gun to the welding welding position of the work, an electric actuator is provided in the equalizing device, and the movement amount on the gun arm side can be regulated steplessly by the electric actuator. Electrode positioning device for robot gun. 2. An elastic means for balancing the weight of the gun is provided between the equalizer and the welding gun, and the balance setting pressure of the elastic means can be adjusted steplessly by an electric actuator. The electrode positioning device according to claim 1. 3. An X-type spot welding gun in which two gun arms pivotally supported by a gun support bracket via hinges are opened and closed by a pressurizing device, and between the gun support bracket and the gun arm. , An electrode positioning device for a robot gun equipped with an electrical actuator that allows the amount of electrode movement to be regulated infinitely. 4. The electrode positioning device according to claim 3, wherein an electric actuator for balancing the gun weight is provided between the gun support bracket and the gun arm. 5. The electrode positioning device according to claim 1, wherein the electric actuator is an electric motor, an electromagnetic solenoid, an electromagnetic magnet, or the like.