JPH09314355A - Method and device for driving spot welding gun - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the operability of a spot welding gun by auxiliarily driving a swinging haft or a supporting member to support a gun arm by varying the rotary torque of a motor arranged between the shaft or the member and a hanging metal by an external output signal. SOLUTION: A gun arm 4 of a C-type welding gun is supported by a hanger part 2 of a hanging metal connected to a balancer through a swinging shat 3. To both end parts of this gun arm 4, a fixing electrode 8 and a moving electrode 9 connected to a low impedance cable 12 are attached. Further, the swinging shaft 3 is made turntable through a gear 6 by pivotaly supporting one end is supported freely turnably with the gun arm 4, supporting another end with a bearing 5, and interposing a driving motor M is interposed between the lower end of the hanger part 2 and the shaft 3. In the case of operating the spot gun, a worker takes an operating handle 14 and presses both electrodes 8, 9 perpendicularly to work striking positions. In this case, the force degree of the operating handle 14 is converted into a signal, the motor M is controlled and the swinging shaft 3 is driven auxiliarily based on the external signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive unit for a portable spot welding gun, and more particularly to a remarkably improved operability of a large welding gun for railway vehicles and automobile bodies.

[0002]

2. Description of the Related Art Conventionally, when welding a hand-worked portion of a large work such as a railroad car or an automobile body, a large portable spot welding gun is hung by a hanging metal fitting so that a human can freely move it. Welding is performed while changing the direction and orientation of the gun according to the work point position.

In this case, in order to operate the rotation of the portable spot welding gun lightly, it is a condition that the center of gravity of the entire gun is coincident with the center of the hanging metal fitting. Generally, a bail support type suspension fitting is generally used to suspend the gun body and balance the weight.

[0004]

However, the conventional device for adjusting the center of gravity is generally designed by standardizing the rear part of the welding gun and changing the depth of the front part of the welding gun. Is difficult by design. Also,
Depending on the processing method of the low reactance cable, the resistance becomes large depending on the rotation angle. In particular, a large gun requires a large torque to rotate, and the torque changes depending on the rotation angle, which puts a heavy burden on the operator and makes the operation difficult. On the other hand, in the bail support type suspension fitting, since the gun body is rotatably supported in the ring, if the structure of the gun becomes large, it will not work in terms of workability.

[0005]

SUMMARY OF THE INVENTION The present invention is to solve the above problems. According to the invention of claim 1, when a spot welding gun hung on a hanging metal fitting is rotatably driven, the welding gun is used. The rocking shaft or the supporting member is supported by the gun arm of, and a motor is arranged between the swinging shaft or the supporting member and the hanging metal fitting that supports the rocking shaft or the supporting member. There is provided a driving method for a spot welding gun, wherein the swing shaft or the supporting member is changed by an output signal from the auxiliary driving device. According to this method, when the welding gun is rotated so that the electrode can be pressed at a right angle with respect to the hitting position of the work, the motor torque automatically changes according to the degree of force applied by the operator, and It can be driven easily even with a shaped gun.

In a second aspect of the present invention, in a device for suspending a spot welding gun on a suspension fitting and operating it freely, a swing arm is swingably supported by a gun arm of the welding gun, and An auxiliary drive device for rotating the swing shaft by a motor drive is arranged between a hanging metal fitting supporting the swing shaft and the swing shaft, and a sensor is incorporated into an operation handle provided on the welding gun. Provided is a drive device for a spot welding gun in which the rotational torque of the motor is changed according to the current value from. According to this device,
By arranging the auxiliary drive device between the swing shaft and the suspension metal fitting, the conventional bail support type suspension metal fitting becomes unnecessary and the structure becomes compact.

According to a third aspect of the present invention, in a device for suspending a spot welding gun on a suspension fitting and operating the suspension fitting freely, a swing shaft is swingably supported by a gun arm of the welding gun. An auxiliary drive device for rotating the swing shaft by a motor drive is arranged between a hanging metal fitting supporting the swing shaft and the swing shaft, and an operation handle provided on the welding gun is provided with two or more directions. A drive device for a spot welding gun incorporating a pressure sensor. According to this device, the motor torque for the auxiliary drive can be changed according to the current value of the pressure sensor, which changes depending on how much the operator's force is applied by the operation handle, so that the operability can be greatly improved. .

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a case where the driving method according to the present invention is applied to a C type portable spot welding gun.

In FIG. 1, reference numeral 1 indicates a spot welding gun. Reference numeral 2 is a hanger portion of the hanging metal fitting whose upper end is connected to the balancer. Reference numeral 3 denotes a swing shaft whose one end is rotatably connected to a gun arm 4 of the spot welding gun, and the other end of the swing shaft is supported by a bearing 5 fixed to the lower end of the hanging fitting, and the swing shaft 3 The pinion 7 of the electric motor M fixed to the hanger portion 2 rotates the gear 6 fixed to the other end of the pinion 7. The fixed electrode 8 is fixed to the tip of the gun arm 4, and the movable electrode 9 is fixed to a movable shaft 11 of an actuator 10 fixed to the gun arm 4. The feed circuit for the fixed electrode 8 and the movable electrode 10 is a low reactance cable 1
2 through the secondary conductor 13. Although the swing shaft 3 is rotatably connected to the gun arm 4, when it is fixed, the support member is fixed to the gun arm instead of the swing shaft.

In FIG. 2, a sensor 15 is incorporated in the operation handle 14 provided on the welding gun, and the rotational torque of the motor is changed according to the current value which changes depending on how the pressure is applied to the sensor. Here is an example.

In this case, when the pressure sensor 15 is installed at the vertical or horizontal position of the handle portion and the portable gun is rotated, the force applied to the pressure sensor 15 depending on how much force is put into the operation handle 14 by the operator. Change. If the force applied to the pressure sensor is large, a current value commensurate with the force is output from the sensor. Conversely, if a small force is applied to the handle, the current value is output small. Therefore,
The motor torque is changed according to the magnitude of the current value output from the sensor 15.

As the pressure sensor 15 in this case, for example, a load cell for forward rotation and a load cell for reverse rotation are used. S is a grip switch of the welding start button.

Next, FIG. 3 shows the driving method according to the present invention.
1 shows an example of a case where it is applied to a portable spot welding gun of a type.

The upper electrode 18 and the lower electrode 19 are two gun arms 21 and 2 which are opened and closed about a main shaft 20.
It is fixed to the tip of 2 respectively. One end of the swing shaft 3 is swingably connected to the center of gravity of the gun arm so that the center of gravity of the entire gun coincides with the center of the suspension fitting. The other end of the swing shaft 3 is supported by a bearing 5 fixed to the lower end of the hanging metal fitting as in FIG. 1, and a gear 6 fixed to the other end of the swing shaft 3 is fixed to the hanger portion 2. The pinion 7 of the electric motor M is configured to rotate.

In FIG. 1, the fixed electrode 8 and the movable electrode 10 can be pressed at right angles to the hitting position of the work,
The operator takes the operation handle and drives the electric motor M around the shaft center of the drive device by adjusting the force applied to the operation handle 14, and visually confirms the state in which the swing angle of the gun is in the proper posture and stops the operation. .

In addition to the swing angle with respect to the work,
Movement in the left-right direction can be handled as usual with a balancer that suspends the entire gun.

As an operation method, the operator uses the handle 1
While pushing the button of 6 (sensor) (load cell), the welding gun rotates the oscillating shaft at an arbitrary angle according to the shape of the work according to the amount of pushing, and the tip of the electrode is moved to the hitting position with respect to the work. After positioning with an appropriate angle,
Release the sensor push button from the operating handle to stop the swing. Then, the grip switch S is pressed to start welding.

If the load goes beyond the load branch point and the load precedes even during normal rotation, the sensor on the reverse side of the grip switch works and the motor starts to rotate in reverse, and the force to stop the operator is generated. Accordingly, the appropriate brake is automatically applied.

Not limited to the embodiment of the present invention, it is also easy to provide an angle detector in the driving device and set the gun posture angle in advance to automatically control the angle. Further, the electric motor M may be a motor with a speed reducer in order to increase the torque.

[0020]

As described above, according to the method of the present invention, when the welding gun is rotated so that the electrode can be pressed at a right angle to the hitting point of the work, the motor is adjusted according to the force applied by the operator. The torque changes automatically, and even a large gun can be driven lightly. According to the device of the present invention, since the auxiliary drive device is arranged between the swing shaft and the hanging metal fitting, the conventional bail support type hanging metal fitting becomes unnecessary, and the structure becomes compact. According to the device of the present invention, since the motor torque for auxiliary drive can be changed according to the current value of the pressure sensor which changes depending on how much the operator's force is applied by the operation handle, the operability can be greatly improved. I chose

[Brief description of drawings]

FIG. 1 is an overall schematic view showing an embodiment when a driving method of the present invention is applied to a C type portable pot welding gun.

FIG. 2 is a conceptual diagram showing a configuration example in which a sensor is incorporated in an operation handle of a drive device of the present invention.

FIG. 3 is an overall schematic view showing an embodiment when the driving method of the present invention is applied to an X type portable pot welding gun.

FIG. 4 is a view on arrow AA of FIG.

FIG. 5 is a schematic diagram showing an example of a case where a drive shaft 3 is rotated by an electric motor M.

[Explanation of symbols]

 1 Spot Welding Gun 2 Hanger Part of Lifting Metal Fitting 3 Swing Shaft 4 Gun Arm 5 Bearing 6 Gear 7 Pinion 8 Fixed Electrode 9 Movable Electrode 10 Actuator 11 Movable Axis 12 Low Reactance Cable 13 Secondary Conductor 14 Operation Handle 15 Sensor 16 Handle M Electric motor

Claims (3)

[Claims] 1. A swing arm or a supporting member is supported by a gun arm of the welding gun, and at the same time, the swing shaft or the supporting member is supported when a spot welding gun hung on a hanging metal fitting is rotatably driven. A spot welding in which a motor is arranged between the hanging metal fitting and the swing shaft or the supporting member, and the rotation torque of the motor is changed by an output signal from the outside to assist the swing shaft or the supporting member. How to drive the gun. 2. A device for suspending a spot welding gun on a suspending metal and freely operating it, in which a swing arm is swingably supported by a gun arm of the welding gun, and a suspension for supporting this swing shaft. An auxiliary drive device for rotating the swing shaft by a motor is arranged between the metal fitting and the swing shaft,
A drive device for a spot welding gun, wherein a sensor is incorporated in an operation handle provided on the welding gun, and the rotational torque of the motor is changed according to a current value from the sensor. 3. The drive device for a spot welding gun according to claim 2, wherein a pressure sensor for two or more directions is incorporated in an operation handle provided on the welding gun.