JPH0866775A - C shape welding gun for robot - Google Patents

Abstract

PURPOSE: To stabilize gun position in traveling a welding gun, to reduce impact/ vibration in pressurizing and to reduce damaging an electrode and work by providing an equalizing unit to C shape welding gun for robot. CONSTITUTION: In the state a moving arm 7 is facing downward, a steel ball 36 of a gun main body position response valve 34 closes an opening 39, pilot pressure is applied from a tube 41 through openings 37, 38 to a tube 42 so as to automatically switch a first pneumatically operated selector valve 18 to (d) port. When a solenoid selector valve 17 is switched under this state, a fixed pressure air is supplied from an air source 20 through a conducting pipe 22 to a chamber 25 of a cylinder 12, cylinders 12, 13 of an equalizing unit 11 are descended to actually move the gun downward. At the same time, because a pressure in a first chamber 29 of cylinder 13 is regulated to balance with the weight of welding gun main body by a pressure regulating device 27 through a conducting pipe 28 and first pneumatically operated selector valve 18, when the welding gun is traveled by robot, etc., there is no free play.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable arm which moves forward and backward by a pressure device, and a C-shaped arm fixed to the pressure device.
The present invention relates to a C-type welding gun for robots in which a pair of electrodes facing each other are attached to the arm and an equalizing unit is interposed between the welding gun body and the operation arm on the robot side.

[0002]

2. Description of the Related Art A pair of electrodes facing each other are attached to a movable arm which moves forward and backward by a pressurizing device and a C-shaped arm fixed to the pressurizing device. A C-type welding gun for a robot, in which an equalizing unit is interposed between the operation arm and the arm, is well known as shown in FIG. That is, 51 is a C-type welding gun,
Is a movable arm 53 driven by a pressurizing cylinder 52.
And a C-shaped fixed arm 54 fixed to the pressurizing cylinder 52, and movably held by a robot-side operation arm 55 via springs 56 and 57.

Then, the operation arm 5 is attached to the work 58.
After the welding gun 51 is positioned in the illustrated state by 5, the movable arm 53 is brought close to the work 58 by the pressure cylinder 52 to bring the electrode 59 into contact with one side of the work 58. When the movable arm 53 is further advanced by the pressure cylinder 52, the entire welding gun 51 is biased by the spring 56 due to the reaction force from the work 58 caused by the contact between the work 58 and the electrode 59. The electrode 60 and the electrode 60
It is adapted to come into contact with the other side of the ring 58. And
Welding is performed with both electrodes 59 and 60 holding the work 58 in between.

[0004]

However, in the case of the above-mentioned conventional example, in order to operate the equalizing unit, a pressurization proportional to the weight of the welding gun and the advancing speed of the movable arm is applied to the work. Therefore, when the movable arm is advanced rapidly, this pressurization causes the work to be distorted, and the work having a weak strength causes deformation.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide an equalizing unit with a function of balancing the weight of the main body of the welding gun. Is added, and the switching signals of the two pneumatic operation switching valves for controlling the cylinder are taken out from the gun body attitude response valve attached to the welding gun body, so that the welding gun can be quickly, easily, and reliably in any welding attitude. An object of the present invention is to provide a robot C-type welding gun in which the weight of the welding gun body does not affect the work and the work can be reliably prevented from being deformed.

[0006]

In order to achieve the above object, in a robot C-type welding gun according to the present invention, an equalizing unit is composed of two cylinders and is arranged between an air source and one cylinder. The equalizing control means of the welding gun body by switching the electromagnetic switching valve, the pressure regulator and the first pneumatic operation switching valve are arranged between the air source and the first chamber of the other cylinder, and the air source and A pressure regulator and a second pneumatic operation switching valve are arranged between the second chamber of the other cylinder, and the welding gun body is balanced by switching between the first pneumatic operation switching valve and the second pneumatic operation switching valve. Control means and the equalizing unit, the switching signal for the first pneumatic operation switching valve and the second pneumatic operation switching valve is taken out from a gun body attitude response valve attached to the welding gun body. What you do That.

[0007]

Since the C-type welding gun for a robot constructed as described above is fixed to the operating arm when the gun is opened, the posture of the gun is fixed when the welding gun is moved. Is stable. Also, during pressurization operation, the signal taken out from the gun body attitude response valve attached to the welding gun body is used to balance the gun by the air pressure in the balancing cylinder corresponding to the attitude of the welding gun body, and the welding operation is performed in that state. Since it is performed, the welding operation can be dealt with in any posture of the welding gun in a balanced state of the gun, and the shock when the electrode tip comes into contact with the work can be softened sufficiently.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. In the figure, reference numeral 1 denotes an operation arm attached to a wrist of a robot, a support member 2 is attached to the operation arm 1, and one end of piston rods 3 and 4 and Sensor-5 is fixed respectively.

Reference numeral 6 denotes an electric or fluid pressurizing device forming a part of the gun body, and the movable arm 7 is movable by the pressurizing device 6.
Is designed to move forward or backward. A C-shaped arm 8 is fixed to the pressurizing device 6, and a pair of electrodes 9 and 10 facing each other are provided at the tips of the C-shaped arm 8 and the movable arm 7. Is installed.

Reference numeral 11 is an equalizing unit, and two cylinders 12 and 13 which are constituent parts of the equalizing unit 11 are fixed to the pressurizing device 6,
A contact piece 14 capable of contacting the sensor 5 is attached to one of the cylinders 12, and one end of the piston rod 3 integrated with a piston 15 in the cylinder 12 has the operation arm. It is fixed to the support member 2 on the first side. Further, one end of the piston rod 4 integrated with the piston 16 in the other cylinder 13 is also connected to the operation arm 1
It is fixed to the side support member 2.

Reference numeral 17 is an electromagnetic switching valve, 18 is a first pneumatic operation switching valve, 19 is a second pneumatic operation switching valve, and pressurized air of a constant pressure (for example, 5 atm that can withstand the total weight of the welding gun). The conduit 21 from the supply source 20 is connected to the electromagnetic switching valve 17, and the electromagnetic switching valve 17 is connected to the chambers 25 and 24 of the cylinder 12 by conduits 22 and 23, respectively. Further, the conduit 26 from the pressurized air supply source 20 is connected to the first pneumatic operation switching valve 18 via a pressure regulator 27, and the first pneumatic operation switching valve 18 is connected to the cylinder 13 by a conduit 28. The pressurized air supply source 20 is connected to the first chamber 29.
30 is connected to the second pneumatic operation switching valve 19 via a pressure regulator 31, and the second pneumatic operation switching valve 19 is connected to the second chamber 33 of the cylinder 13 by a conduit 32. It is like this.

The first pneumatic operation switching valve 18 and the second pneumatic operation switching valve 19 are switched by a gun body attitude response valve 34 mounted on the outer surface of the pressurizing device 6, which is a part of the gun body. The action is taken. The gun body attitude response valve 34
Is a substantially T-shaped internal space 35 as shown in FIGS.
A steel ball 36 is movably arranged in the space 35, and openings 37, 38, 39 are provided on three sides. A pilot pressure supply pipe 41 connected to the pressurized air supply source 20 side is connected to the opening 37 via a pressure reducing device 40, and an opening 38 is a pilot pressure supply pipe 42 to the first pneumatic operation switching valve 18. And the pilot pressure supply pipe 43 to the second pneumatic operation switching valve 19 is connected to the opening 39.

When the movable arm 7 is in the downward direction as shown in FIG. 1, the gun body attitude response valve 34 has a steel ball 36 which closes the opening 39 as shown in FIG. By acting on the pipe 42 via 38, the first pneumatic operation switching valve 18 is automatically switched to the d port. And tube 4
Since the pilot pressure does not act on 3, the second pneumatic operation switching valve 19 remains at the g port. In this state, the electromagnetic switching valve 17 is switched to the a port to completely open the gun. As a result, when a constant pressure of air is supplied from the air source 20, the air is supplied from the electromagnetic switching valve 17 to the conduit 22.
Is supplied to the chamber 25 of the cylinder 12 through the cylinder 12,
13 is lowered to move the gun substantially downward,
4 is discharged from the conduit 23 through the electromagnetic switching valve 17, and at the same time, the pressure in the first chamber 29 of the cylinder 13 is increased. Since the pressure is adjusted by the pressure adjusting device 27 via the pneumatic operation switching valve 18 so as to balance with the weight of the welding gun main body, the air pressure in the first chamber 29 is maintained at a predetermined pressure. By this operation, the welding gun main body is fixed to the operation arm 1 on the robot side by the air in the chamber 25 of the cylinder 12. In this state, when the welding gun is moved by the robot, the gun can move in a stable posture without rattling.

In addition, a movable arm is used to perform a welding operation.
In the initial stage of pressurization of the work for advancing the work 7 with respect to the work, the electromagnetic switching valve 17 is switched to the c port. As a result, when air of a constant pressure is supplied from the air source 20, the air is supplied from the electromagnetic switching valve 17 to the chamber 24 of the cylinder 12 via the conduit 23, and the cylinders 12 and 13 are lifted to substantially cause the gun. And the air in the chamber 25 moves to the conduit 2
2 is discharged through the electromagnetic switching valve 17, and at the same time, the pressure in the first chamber 29 of the cylinder 13 is reduced.
Air whose pressure has been adjusted is supplied from the air source 20 to the inside of the first chamber 29 through the pressure adjusting device 26 and the first pneumatic operation switching valve 18.
The internal pressure is a predetermined pressure and is always in balance with the weight of the welding gun body.

By this operation, the welding gun main body is gradually lifted up, and the air pressure in the first chamber 29 of the cylinder 13 is balanced with the weight of the welding gun main body even during this rising. Then, as the cylinders 12 and 13 rise, the contact piece 14 fixed to the cylinder 12 pushes up the sensor-5,
The electromagnetic switching valve 17 is switched to the b port by this signal. In this state, the pressures in the chambers 24 and 25 of the cylinder 12 are balanced, so that the cylinder 12 thereafter performs the equalizing control operation of the welding gun body.

While the air is being supplied to the chamber 24 of the cylinder 12, the pressurizing device 6 moves the movable arm 7 forward to the work chamber. At the same time when the electrode 10 approaches the work by supplying air to the work, the movable arm 7 simultaneously approaches the work of the electrode 9, and both electrodes 9 and 10 may simultaneously contact the work. Yes, or one of the electrodes may come into contact with the work first, but the weight of the welding gun body is substantially balanced by the air pressure in the first chamber 29 at the time of this contact. The influence of the weight of the welding gun body on the work is almost nonexistent. Regarding the pressure adjustment in the pressure adjusting devices 27 and 31, if the pressure corresponding to the welding posture of the welding gun is adjusted in advance so that the pressure adjusting device 27 side is slightly higher than the pressure adjusting device 31 side, for example. Good.

The above is a description of the case where the movable arm 7 is in a gun posture such as downward, as shown in FIG. 1. However, when the movable arm 7 is in a gun posture such as upward, As shown in FIG. 3, the body attitude response valve 34 has a steel ball 36 with an opening 38.
And the pilot pressure acts on the pipe 43 from the pipe 41 through the openings 37 and 39 to automatically switch the second pneumatic operation switching valve 19 to the f port. Since the pilot pressure does not act on the pipe 42, the first pneumatic operation switching valve 18 becomes the e-port. This balances the weight of the welding gun body with the air pressure in the second chamber 33 of the cylinder 13. Further, when the movable arm 7 is in a gun attitude such that it is oriented substantially horizontally, the gun body attitude response valve 34 has a steel ball 36 closing the opening 37 as shown in FIG. The first pneumatic operation switching valve 18 is automatically moved to the e port and the second pneumatic operation switching valve 19 is automatically moved to the g port without reaching the operation switching valve 18 and the second pneumatic operation switching valve 19 side. To do.

In the above embodiment, the two cylinders 12 and 13 which are components of the equalizing unit 11 are used.
I explained about the one that is fixed to the pressurizing device 6 side,
The cylinders 12 and 13 may be fixed to the support member 2 on the operation arm 1 side, and the piston rods 3 and 4 and the sensor 5 may be attached to the pressure device 6 side.

[0019]

According to the present invention, since the welding gun is fixed to the operation arm when the gun is opened, the posture of the welding gun is stable when the welding gun is moved, and the welding gun is moved by the robot. Is accurate and easy.

Balancing control means provided in the equalizing unit is applied to balance the weight of the gun at the initial stage of pressurization, and the first pneumatic operation switching valve and the second pneumatic pressure are applied in accordance with the welding posture of the welding gun. The operation switching valve is automatically switched quickly and reliably, so the welding gun is held in the optimum state for the welding position of the welding gun, so there is little shock or vibration during pressurizing operation and the electrodes and work are damaged. It becomes a safe cancer with few things.

[Brief description of drawings]

FIG. 1 is a side view of a main part of a robot C-type welding gun according to the present invention.

FIG. 2 is a sectional view of a gun body attitude response valve applied to the robot C-type welding gun according to the present invention.

FIG. 3 is an explanatory sectional view of a gun body attitude response valve corresponding to the attitude of the welding gun.

FIG. 4 is an explanatory cross-sectional view of a gun body attitude response valve corresponding to another attitude of the welding gun.

FIG. 5 is a side view of a conventional robot C-type welding gun.

[Explanation of symbols]

 1 Operation Arm 6 Pressurizing Device 7 Movable Arm 8 C Type Arm 9, 10 Electrode 11 Equalizing Unit 12, 13 Cylinder 17 Electromagnetic Changeover Valve 18 First Pneumatic Operation Changeover Valve 19 Second Pneumatic Operation Changeover Valve 20 Air source 27,31 Pressure regulator 34 Gun body attitude response valve

Claims (1)

[Claims] 1. A pair of electrodes facing each other are attached to a movable arm that moves forward and backward by a pressurizing device and a C-shaped arm fixed to the pressurizing device. In a robot C-type welding gun in which an equalizing unit is interposed between an operation arm and the equalizing unit, the equalizing unit is composed of two cylinders, and an electromagnetic switching valve arranged between an air source and one of the cylinders. The equalizing control means of the welding gun body by switching, the pressure regulator and the first pneumatic operation switching valve are arranged between the air source and the first chamber of the other cylinder, and the air source and the first chamber of the other cylinder are arranged. A pressure regulator and a second pneumatic operation switching valve are arranged between the two chambers, and a welding gun body balancing control means by switching between the first pneumatic operation switching valve and the second pneumatic switching valve. Equipped with equalizing unit A C-type welding gun for a robot characterized in that switching signals for the first pneumatic operation switching valve and the second pneumatic operation switching valve are taken out from a gun body attitude response valve attached to the welding gun body.