JPH06335781A - Pressurizing method and device for resistance welding - Google Patents

Abstract

PURPOSE:To perform economical welding with little consumption of an electrode and air by giving the welding force added with the storage force and the welding force to hold materials to be welded between when the welding force is applied. CONSTITUTION:A cylinder 2 having a piston rod 5 fitted with an electrode tip 4 in opposition to an electrode tip 3 fitted on a C-type gun frame 1 is arranged. In the pressurizing process to hold the materials to be welded between the electrode tips 3 and 4, the speed of the electrodes 3 and 4 is attenuated gradually and the sufficient force for opening the electrodes is stored by pressing a pressing rod 10 and a leaf spring 6 of a repulsive constituent member. When the welding force is applied, the welding force added with the storage force and the welding force to hole the materials to be welded between is given. The welding force is obtained by a pneumatic actuator. Consequently, even when soft materials such as aluminum sheets are welded, welding with little impression can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding pressurizing gun suitable for a resistance welding robot, and more particularly to a pressurizing method and apparatus for suppressing collision of electrodes during a process of sandwiching an object to be welded.

[0002]

2. Description of the Related Art C-shapes and X-shapes conventionally used for robot welding
The pressure-opening / closing method of a shaped gun is generally used when welding air at multiple points within a unit time by replacing the air supply / discharge on the front and rear surfaces of the piston of the pneumatic double-acting cylinder to open / close the electrode under pressure. ,
The air was smoothly supplied and discharged, and the cylinder was moved at high speed to open and close the electrodes.

[0003]

In the prior art, the object to be welded is clamped when the movement of the electrode is gradually accelerated and is maximally accelerated in the pressing process of pressing the object to be welded. Therefore, there is a problem in that the tip of the electrode collides with the object to be welded to generate noise, the tip of the electrode is worn away, spatter is generated and the electrode is worn out, and the number of continuous dots is small.

[0004]

In order to solve the above problems, in the pressing method of the present invention, the movement of the electrode is gradually decelerated when the object to be welded is sandwiched. Therefore, in resistance welding in which a welding pressure is obtained with a pneumatic actuator, the force that gradually increases in the electrode opening direction during the pressure process of sandwiching the work piece is It is characterized in that a force of 3 or more is applied, and a pressure force obtained by adding the pressure force and the welding pressure force sandwiching the object to be welded at the time of welding pressure is applied.

Specifically, the pressure of the resistance welding gun is set to an air pressure actuator having a pressing force that is 1/3 or more larger than the required welding pressing force, and the elastic component members are simultaneously pressed during the pressing process to open the electrode. A resistance welding pressurizing device is constructed such that a force gradually increasing in a direction is accumulated in the elastic component member and the accumulated force is set to ⅓ or more of a necessary welding pressure when the electrodes come into contact with each other.

[0006]

First Embodiment A cylinder 2 having a piston rod 5 having an electrode tip 4 attached thereto is arranged so as to face the electrode tip 3 attached to a C-shaped gun frame 1. One end of a leaf spring 6 is fixed to the frame 1 by screws 9 on both side surfaces of the frame 1, and the other end is in contact with a push rod 10 arranged on a piston rod 5. The pressing side of the cylinder 2 is connected to the 3-port solenoid valve 7 by an air hose,
A throttle valve 8 is arranged on the return side of the cylinder 2.

When the solenoid valve 7 is actuated, the piston rod 5 receives the pushing force and moves forward until the electrodes 3 and 4 come into contact with each other.
Since the exhaust gas is suppressed, the volume gradually decreases as the piston rod 5 moves forward, the pressure increases, and the force that pushes back the piston rod 5 increases. Further, the push rod 10 arranged on the piston rod 5 gradually bends the leaf spring 6 to increase the force for pushing back the piston rod 5.

The force of pushing back the piston rod 5 which gradually increases by the two elastic component members suppresses the projection of the piston rod 5 like a shock absorber,
While preventing problems such as noise and tip wear, spatter generation, and deterioration of the number of continuous dots, which are problems in the past when welding continuously and at high speed, the solenoid valve 7 is repelled when operated in reverse. The pressure accumulated in the constituent members serves as a force to push the piston rod 5 back to its original position.

This pushing back elastic force must be sufficient to separate the electrode and the object to be welded during welding. (In the case of 1 mm thick plated steel plate welding, the welding pressure is about 250 kg, and the force for separating the adherence is about 150 kg.)
Further, when the number of continuous welding points is large, the piston withdrawal speed becomes faster, so that the force for pushing back the piston rod 5 as a shock absorber is also large, and substantially 1/2 of the welding required pressing force is required. Therefore, the pushing force of the cylinder 2 is a load obtained by adding about 1/2 of the pressing force required for welding to the pressing force required for welding.

The fact that the amount of pushing force of the cylinder 2 is more than 30% larger than that of the conventional one seems to cause a large energy loss, but when the 3-port solenoid valve 7 is operated in reverse, it has a resilient structure. Since the force accumulated in the member becomes the force that pushes the piston rod 5 back to its original position,
Compared to the conventional method in which the supply and discharge of air is switched between before and after the piston, it consumes less air and requires only one air hose, which is economical. The elastic component may be composed only of a leaf spring or a compression or tension coil spring.

[0011]

[Embodiment 2] The pressing arms 11 and 12 are integrally held by leaf springs 15 arranged on both side surfaces of the central portion.
An electrode tip 1 is provided at the front ends of the pressure arms 11 and 12.
A pressurizing cylinder 18 is arranged at the rear end of the cylinders 3, 14, the pushing side of the cylinder is connected to a 3-port solenoid valve 19 by an air hose, and a throttle valve 20 is arranged at the pushing back side.

When the 3-port solenoid valve 19 is actuated, the piston rod is pushed out and the leaf spring 15 is bent and pushed out until the electrodes 13 and 14 come into contact with each other. In the pushing process of this piston rod, the cylinder is returned. Since the exhaust is suppressed by the throttle valve 20 on the side, the volume gradually decreases as the piston moves forward, the pressure increases, and the force that pushes back the piston increases. The leaf spring 15 also gradually increases in pushing back force in the process of bending, and becomes a resilient component member. Therefore, as in the case of the first embodiment, this elastic force serves as a shock absorber at the time of welding and pressing, and also serves as a force for opening the electrodes and returning them to the original position.

[0013]

Third Embodiment A pressure arm 25 having an electrode 24 arranged to face the electrode 23 of a C-shaped frame 21 has a C-shape by means of two sets of leaf springs 27 and 28 which are arranged on both sides and are spaced apart. It is connected to the frame 21. Further C-shaped frame 21
A bellows type air actuator 22 is arranged between the rear end and the pressure arm 25, and is connected to a 3-port solenoid valve 31 by an air hose.

When the 3-port solenoid valve 31 is actuated, the bellows type air actuator 22 extends to push out the pressure arm 25, and two sets of leaf springs 2 are connected.
While pushing and bending 7, 28 until the electrodes 23, 24 come into contact with each other, the elastic force that pushes back the two sets of leaf springs 27, 28 that are pushed and bent in this pushing process gradually increases, similar to the case of the first embodiment. This elastic force serves as a shock absorber at the time of pressurizing the welding, and also serves as a force for opening the electrodes and returning them to the original position.

The two sets of leaf springs 27 and 28 for connecting the pressure arm 25 and the C-shaped frame 21 are attached by tilting them so that the pressure arm 25 side is rearward.
If 4 is made to be close to vertical when in contact with each other, the displacement of the tip of the electrode is small even when the electrode is consumed. Alternatively, the leaf spring 28 side may be slightly shortened so that the electrode side of the pressing arm 25 is slightly upward in the pressing process to correct the positional deviation of the electrode tip. When the electrodes are separated from each other, if the pressing arm 25 and the leaf spring are attached to each other by a pivot, the leaf spring is easily bent, so that the stroke can be easily taken.

[0016]

[Embodiment 4] Two sets of leaf springs 36, 37 spaced apart are fixed to both sides of the central portions of the pressure arms 32, 33 having electrodes 34, 35 at their ends by attaching screws 38-41 at both ends. The front leaf spring 36 is slightly bent rearward. A bellows type actuator 43 is arranged at the rear ends of the pressure arms 32 and 33, and is connected to a 3-port solenoid valve 42 by an air hose.

When the 3-port solenoid valve 42 is actuated, the bellows type air actuator 43 extends and pushes the rear ends of the pressure arms 32 and 33 in opposite directions to expand and connect the two sets of leaf springs 36. , 37 while pushing and bending, push up until the electrodes 34, 35 come into contact. The elastic force of the two sets of leaf springs 36 and 37 bent during the pushing-up process gradually increases. As in the case of the first embodiment, this elastic force acts as a shock absorber during welding pressurization and also between the electrodes. Will be the force to open and return to the original position.

Since the front leaf spring 36 is bent slightly backward, the entire bending is smooth even if two sets of leaf springs are bent at the same time. Further, since the two sets of leaf springs 36, 37 are arranged with a space therebetween, the movements of the two sets of leaf springs 36, 37 are regulated to each other and limited to prevent displacement of the electrodes.

As described above, the present invention applies a force of ⅓ or more of the welding pressure required during welding in the electrode opening direction,
By applying a pressure force obtained by adding the pressure force at the time of welding pressurization and the welding pressure force sandwiching the object to be welded by the pneumatic actuator, the protrusion of the piston rod 5 is suppressed like a shock absorber and the tip of the electrode is The solenoid valve 7 is used to prevent the harmful effects such as the collision with the work piece, the generation of noise, the wear of the electrode tip, the generation of spatter, and the small number of continuous dots.
When it is operated in reverse, good welding quality such as a force for pushing the piston rod 5 back to its original position can be obtained, and economical welding with less consumption of electrodes and air can be performed. Further, since the tip of the electrode does not collide with the object to be welded, even if a soft material such as an aluminum plate is welded, welding with less indentation can be performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram in which the present invention is used for a C-shaped gun.

FIG. 2 is a configuration diagram in which the present invention is used for an X-shaped gun.

FIG. 3 is a configuration diagram in which the present invention is used for another type of C-shaped gun.

FIG. 4 is a configuration diagram in which the present invention is used for another type of X-shaped gun.

[Explanation of symbols]

 1. C-shaped arm, 2. Pressure cylinder, 3,4. Electrode, 5. Piston rod, 6. Leaf spring 7.3 port solenoid valve, 8. Throttle valve, 9. Mounting screw 10. Push rod, 11, 12. Pressure arm, 13, 14. Electrode, 15. Leaf spring, 16, 17. Mounting screws, 18. Pressure cylinder, 19.3 port solenoid valve, 20. Throttle valve, 21. C-shaped frame 22. Bellows type air actuator 23, 24. Electrode 25. Pressure arm 27, 28. Leaf spring 29,30. Mounting screw 31.3 port solenoid valve, 32, 33. Pressure arm 34, 35. Electrodes 36, 37. Leaf spring 38-41. Mounting screw 42.3 port solenoid valve, 43. Bellows type air actuator

Claims (3)

[Claims] 1. In resistance welding for obtaining a welding pressure force by a pneumatic actuator, a velocity of an electrode is gradually attenuated during a pressure process of sandwiching an object to be welded, and a force sufficient to open the electrode is elastically released. A pressurizing method for resistance welding, comprising pressing and accumulating, and applying a pressurizing force obtained by adding the accumulating force and a welding pressurizing force for sandwiching an object to be welded at the time of pressurizing welding. 2. A means for accumulating a force sufficient to open the electrode by depressing the elastic component in the process of pressurizing the resistance welding gun to press the object to be welded, and the accumulated pressure. And a pressure welding device for resistance welding, in which a pneumatic actuator that adds the required welding pressure to the electrode tip is placed. 3. The resistance welding according to claim 2, wherein a pressure arm having electrodes facing each other at a distance is arranged, the two are connected by two sets of leaf springs, and a pneumatic actuator is arranged between the pressure arms. Pressurizing device.