JP3375190B2 - C type welding gun for robot - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable arm which moves forward and backward by a pressing device, and a C-shaped arm fixed to the pressing device.
The present invention relates to a C-type welding gun for a robot in which a pair of electrodes facing each other are attached to a robot and an equalizing unit is interposed between the welding gun body and an operation arm on the robot side. 2. Description of the Related Art 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. 2. Description of the Related Art As shown in FIG. 2, a C-type welding gun for a robot in which an equalizing unit is interposed between the robot and an operation arm on the robot side is well known. That is, 31 is a C-type welding gun.
Is a movable arm 33 driven by a pressure cylinder 32
And a C-type fixed arm 34 fixed to the pressurizing cylinder 32, and is movably held by a robot-side operation arm 35 via springs 36 and 37. [0003] Then, the operation arm 3 is
After the welding gun 31 is positioned in the state shown in FIG. 5, the movable arm 33 is brought close to the work 38 by the pressurizing cylinder 32 to bring the electrode 39 into contact with one side of the work 38. When the movable arm 33 is further advanced by the pressurizing cylinder 32, the welding gun 31 as a whole is biased by the spring 36 due to the reaction force from the work 38 caused by the contact between the work 38 and the electrode 39. Electrode 40 is retracted against the
The contact 38 is brought into contact with the other side. And
Welding is performed with both electrodes 39 and 40 sandwiching the work 38. [0004] However, in the case of the above-mentioned conventional example, in order to operate the equalizing unit, the work is added to the work in proportion to the weight of the welding gun and the moving speed of the movable arm. When pressure is applied and the movable arm advances quickly, there is a problem that the work is distorted by the pressurization, and the work is weakly deformed. The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a cylinder in which an equalizing unit has a function of balancing the weight of a welding gun body. By providing a C-type welding gun for a robot, the weight of the welding gun body does not affect the work in any welding position of the welding gun and the deformation of the work is reliably prevented. It is assumed that. In order to achieve the above object, a C-type welding gun for a robot according to the present invention comprises an equalizing unit composed of two cylinders and an air source and one cylinder. An equalizing control means for the welding gun body by switching the first electromagnetic switching valve having a first electromagnetic switching valve interposed therebetween, and a pressure regulator and a second electromagnetic switching valve arranged between the air source and the other cylinder. The equalizing unit has a balancing control means for the welding gun body by switching the second electromagnetic switching valve. The C-type welding gun for a robot configured as described above is fixed to the operation arm when the gun is opened, so that the welding gun is fixed when the welding gun is moved. The posture of the gun stabilizes. In addition, during pressurization operation, the gun is brought into a balanced state by the air pressure in the balancing cylinder, and the welding operation is performed in that state, so that the welding operation can be dealt with in any posture of the welding gun with a simple gun balanced state. Also, the shock when the electrode tip comes into contact with the work can be sufficiently relieved. An embodiment of the present invention will be described with reference to FIG. In the drawing, reference numeral 1 denotes an operation arm attached to a wrist of a robot. The operation arm 1 has a support member 2 attached thereto. The support member 2 has one end of piston rods 3, 4 and Each of the sensors 5 is fixed. Reference numeral 6 denotes an electric or fluid pressurizing device which forms a part of the gun body.
Is designed to move forward or backward. Further, a C-type arm 8 is fixed to the pressurizing device 6, and a pair of electrodes 9, 10 opposed to each other are provided at the respective ends of the C-type arm 8 and the movable arm 7. Is installed. Reference numeral 11 denotes an equalizing unit, and two cylinders 12, 13 which are components of the equalizing unit 11 are fixed to the pressurizing device 6,
A contact piece 14 that can contact 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 is connected to the operating arm. It is fixed to the support member 2 on one side. One end of the piston rod 4 integrated with the piston 16 in the other cylinder 13 is also connected to the operating arm 1.
Is fixed to the supporting member 2 on the side. Reference numeral 17 denotes a first solenoid-operated switching valve, and 18 denotes a second solenoid-operated switching valve. The first electromagnetic switching valve 17 is connected to the first electromagnetic switching valve 17.
Are connected to the chambers 23, 2 of the cylinder 12 by conduits 21, 22.
4 respectively. A conduit 25 from the pressurized air supply source 19 is connected to the second
The second electromagnetic switching valve 18 is connected to the electromagnetic switching valve 18 and connected to the chambers 29 and 30 of the cylinder 13 by conduits 27 and 28, respectively. In the state shown in FIG. 1, in order to completely open the gun, the first solenoid-operated switching valve 17 is switched to the port a. As a result, when air at a constant pressure is supplied from the air source 19, the air is supplied from the first electromagnetic switching valve 17 to the chamber 24 of the cylinder 12 via the conduit 21 to lower the cylinders 12 and 13 to substantially operate the gun. The air in the chamber 23 is discharged from the conduit 22 through the first electromagnetic switching valve 17,
At the same time, the pressure in the chamber 29 of the cylinder 13 is increased, but the air in the chamber 29 is balanced with the weight of the welding gun body by the pressure regulating device 26 via the conduit 27 and the second electromagnetic switching valve 18. Therefore, the air pressure in the chamber 29 is maintained at a predetermined pressure. By this operation, the welding gun body is fixed to the operation arm 1 on the robot side by the air in the chamber 24 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. Further, a movable arm is provided for performing a welding operation.
In the initial stage of work pressurization in which the arm 7 is moved forward with respect to the work, the first electromagnetic switching valve 17 is switched to the c port. Thus, when air at a constant pressure is supplied from the air source 19,
The air is supplied from the first electromagnetic switching valve 17 via the conduit 22 to the chamber 23 of the cylinder 12 and lifts the cylinders 12 and 13 to move the gun substantially upward. (1) The gas is discharged through the electromagnetic switching valve 17 and at the same time, the pressure in the chamber 29 of the cylinder 13 decreases.
9 from the air source 19 to the pressure regulator 26, the second electromagnetic switching valve 1
The pressure regulated air is supplied via 8 and the pressure in the chamber 29 is always in balance with the weight of the welding gun body at a predetermined pressure. By this operation, the welding gun body is gradually lifted.
The air pressure inside is balanced with the weight of the welding gun body.
Then, as the cylinders 12 and 13 rise, the cylinder 12
The contact piece 14 fixed to the above pushes up the sensor 5 and switches the first solenoid-operated switching valve 17 to the b-port by this signal. In this state, since the pressures in the chambers 23 and 24 of the cylinder 12 are balanced, the cylinder 12 thereafter performs the equalizing control operation of the welding gun body. When the movable arm 7 is moved forward by the pressurizing device 6 while the air is being supplied to the chamber 23 of the cylinder 12, the chamber 23 of the cylinder 12 is moved forward. The movable arm 7 approaches the work of the electrode 9 at the same time as the work of the electrode 10 approaches the work by the supply of air to the work, and both the electrodes 9 and 10 may come into contact with the work at the same time. Yes, or one of the electrodes may come into contact with the work first, but at this time, the weight of the welding gun body is substantially balanced by the air pressure of the chamber 29. The effect of the weight of the welding gun body on the weld is almost nonexistent. The amount of pressure adjustment in the pressure adjusting device 26 can be made extremely accurate by pre-tating the pressure corresponding to the welding position of the welding gun. The above is a description of the case where the movable arm 7 is in the gun posture such as downward as shown in FIG. 1. (2) The weight of the welding gun body is balanced by the air pressure in the chamber 30 of the cylinder 13 by switching the electromagnetic switching valve 18 to the e port. In the above embodiment, two cylinders 12 and 13 which are components of the equalizing unit 11 are used.
Has been described on 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 mounted on the pressurizing device 6 side. According to the present invention, since the welding gun is fixed to the operation arm when the gun is opened, the posture of the gun is stabilized when the welding gun is moved, and welding by the robot is performed. The gun can be moved accurately and easily. Further, a balancing control means provided in the equalizing unit is applied to balance the weight of the gun in the initial stage of pressurization, and the welding gun is held in a state optimal for the welding posture of the welding gun. Impact at
It is a safe gun with less vibration and less damage to electrodes and work.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a main part of a C-type welding gun for a robot according to the present invention. FIG. 2 is a side view of a conventional C-type welding gun for a robot. [Description of Signs] 1 Operating arm 6 Pressurizing device 7 Movable arm 8 C-shaped arm 9, 10 Electrode 11 Equalizing unit 12, 13 Cylinder 17 First electromagnetic switching valve 18 Second electromagnetic switching valve 19 Air Source 26 Pressure regulator

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23K 11/11

Claims (1)

(57) [Claim 1] A pair of electrodes facing each other is provided on a movable arm which moves forward and backward by a pressurizing device and a C-shaped arm fixed to the pressurizing device. In a C-type welding gun for a robot in which an equalizing unit is interposed between a mounting gun body and an operation arm on a robot side, the equalizing unit is constituted by two cylinders, and an air source and one cylinder are connected to each other. An equalizing control means for the welding gun body by switching the first electromagnetic switching valve in which the first electromagnetic switching valve is disposed, and a pressure regulator and a second electromagnetic switching valve disposed between the air source and the other cylinder A robotic C-type welding gun, characterized in that the equalizing unit includes a balancing control means for the welding gun body by switching the second electromagnetic switching valve.