JPS6224187B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stationary welding device that performs spot welding on two workpieces stacked together.

Generally, stationary welding equipment for spot welding is
Two workpieces are placed on a fixed electrode, the movable electrode is lowered, and the workpieces are pressed and clamped between this and the fixed electrode, and then a large current is passed between both electrodes to weld the two workpieces together. It is for the purpose of By the way, when the workpiece is inserted between the two electrodes using an industrial robot and welded, the workpiece is inserted slightly above the fixed electrode so that the workpiece does not hit the fixed electrode. However, in such cases, the workpieces are welded by an industrial robot while the workpieces are held at the height at which they were inserted. There was a problem in that the workpiece was deformed because the welded part was pushed down and held between the fixed electrodes.

Conventionally, in order to solve such problems,
As shown in Japanese Utility Model Application Publication No. 56-6581, the welding gun is slid upward so that the fixed electrode comes into contact with the workpiece inserted between the fixed and movable electrodes, and then the movable electrode is lowered to clamp the workpiece. I found something that was supposed to be welded. However, this method requires a slide mechanism to move the heavy welding gun up and down, resulting in an increase in the size and cost of the device.

The present invention has been made in view of the problems of the conventional products, and consists of arranging a welding material loading section, a welding material discharging section, and a spot welding gun on a circumference centered on one point. The workpiece is held at the center of the periphery by the workpiece holding part, and the workpiece is held between the workpiece loading section and the spot welding gun, and between the spot welding gun and the welding workpiece unloading section. The spot welding gun includes a gun arm having a first end and a second end, and a fixed electrode facing each of the first and second ends of the gun arm. A movable electrode is attached, and the base of the gun arm is rotatably supported on a stationary stand.
Furthermore, between the spot welding gun and the stationary stand,
By providing a rotation drive mechanism that rotates the spot welding gun so that the fixed electrode comes into contact with the workpiece inserted between the fixed and movable electrodes, the workpiece can be welded with a simple structure and without increasing costs. It is an object of the present invention to provide a welding device that can prevent deformation of the welding material, reduce welding time, and improve welding efficiency.

An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show an embodiment of the present invention,
In the figure, on the circumference centered on the industrial robot 1, there is a welding workpiece carrying-in section 2, a spot welding gun 3,
and a workpiece carrying-out section 4 are arranged at regular angular intervals. The workpiece carrying-in section 2 is for carrying a workpiece 5, such as a workpiece 5 formed by overlapping a rear pillar and rear fender, into the welding apparatus from the outside, and the workpiece carrying-out section 4
is for transporting the welded workpiece 5 out of the welding apparatus.

Further, the industrial robot 1 is installed on a floor surface 6 so as to be rotatable around its legs 1a, and an arm 1b extending horizontally is formed at the upper end of the legs 1a. A workpiece setting jig 1c, which is a welding object holding part that holds the workpiece 5, is attached to the tip of the arm part 1b.
The workpiece setting jig 1c can be reciprocated along the circumference between the welding object loading section 2 and the spot welding gun 3, and between the spot welding gun 3 and the welding object unloading section 4. ing.

The spot welding gun 3 is composed of a gun arm 7, a movable electrode section 8, and a fixed electrode section 9, and the gun arm 7 includes a base section 7a, an upper arm 7b integrally formed substantially horizontally following the upper end of the base section 7a, and It is U-shaped, consisting of a lower arm 7c integrally formed substantially horizontally following the lower end of the base 7a. Further, a movable electrode mounting bracket 7e is integrally formed at the tip 7d of the upper arm 7b, which is the first end of the gun arm 7. An air cylinder 8a is attached, and a movable electrode 8d is fixed downwardly to the lower end of the piston rod 8b of the vertically moving air cylinder 8a by a connecting member 8c.

Further, a fixed electrode mounting bracket 7g is integrally formed at the tip 7f of the lower arm 7c, which is the second end of the gun arm 7. A fixed electrode 9b is fitted and fixed to the bracket 9a facing the movable electrode 8d.

A rotating bracket 10 having shaft portions 10a on the left and right sides is bolted to the center of the base 7a of the gun arm 7, and the rotating bracket 10 is attached to the left and right columns 11a of the stationary base 11.
inserted in between. Further, a bearing 12 is bolted and fixed to the upper end of the outer surface of both columns 11a, and the shaft portion 10a of the rotating bracket 10 is rotatably fitted into the bearing 12 and supported. The gun arm 7 is rotatable relative to the support column 11a. Further, a stopper bracket 13 is bolted and fixed below the rotation bracket 10 on the inner surface of the support column 11a.
A stopper bolt 1 is attached to the stopper bracket 13.
3a is screwed and fixed, and the distal end surface of the stopper bolt 13a can come into contact with an abutment plate 7h fixed to the lower part of the base 7a of the gun arm 7.

Also, the left and right pillars 11a are the fixed bases 11
The base 11b is bolted perpendicularly to the upper surface of the base 11b, and the base 11b is formed of a steel plate into a substantially rectangular parallelepiped shape, and its lower surface is fixed to the floor surface 6.

On the front of the upper surface of the base 11b, the left,
A cylinder support bracket 14 having a right support plate 14a is fixed with bolts, and a cylinder connection bracket 15 having a connection plate 15a is fixed with bolts to the lower front part of the lower arm 7c of the gun arm 7, and both brackets are fixed with bolts. 1
An air cylinder 16 serving as a rotational drive mechanism for the spot welding gun 3 is disposed between 4 and 15, and the lower end of the air cylinder 16 is fitted between the support plates 14a of the cylinder support bracket 14. It is rotatably supported on a shaft 14b.
Also, the piston rod 16 of the air cylinder 16
A connecting member 17 is screwed onto the tip of the cylinder a, and the tip of the connecting member 17 is fitted into the connecting plate 15a of the cylinder connecting bracket 15, and the shaft 15b
are rotatably connected.

Next, the operation will be explained.

First, the movement of the workpiece 5 will be explained. When the workpiece 5 is carried into the workpiece loading section 2 using a crane or the like, the workpiece 5 is held in the workpiece setting jig 1c of the industrial robot 1, and
The spot welding gun 3 is then transported along the circumference to the spot welding gun 3. Then, when a predetermined part to be welded is spot welded in the spot welding gun 3,
The workpiece 5 is transported along the circumference to the workpiece delivery section 4.
From the welding object carrying-out section 4, the welding material is carried out by a crane or the like to the outside of the welding apparatus.

Next, a welding operation using the spot welding gun 3 will be explained. At the start of welding work, the spot welding gun 3 is rotated to its lower end position, the contact plate 7h of its base 7a is in contact with the tip end surface of the stopper bolt 13a, and the movable electrode 8
d has been raised to its rising end position, and in this way, the movable electrode 8d and fixed electrode 9b are separated from each other by a constant distance. In this state, the workpiece 5 is attached to the workpiece setting jig 1c of the industrial robot 1.
is held by the fixed electrode 9b and transferred horizontally.
The workpiece 5 is inserted slightly above the upper end surface, and stops when the workpiece to be welded comes directly above the fixed electrode 9b.

When the workpiece 5 stops, the air cylinder 1
6 rotates the spot welding gun 3 counterclockwise in FIG. 2 until the upper end surface of the fixed electrode 9b comes into contact with the lower surface of the workpiece 5. When this fixed electrode 9b comes into contact with the workpiece 5, the movable electrode 8d descends,
The workpiece 5 is pressed against the upper end surface of the fixed electrode 9b by the lower end surface of the movable electrode 8d, and in this state a large current flows between the electrodes 8d and 9b, thereby spot welding the workpiece 5. When the welding is finished, the movable electrode 8d is raised, and the spot welding gun 3 is moved by the air cylinder 16 so that the contact plate 7h of the gun arm 7 is moved to the stopper bolt 13.
The workpiece 5 is rotated clockwise in FIG. 2 until it comes into contact with the tip end surface of the electrode a, and the workpiece 5 is rotated clockwise in FIG. It is moved a little at the same height position so as to match 9b, and the welded part is then welded in the same manner as above.

When all the welding is completed and the movable electrode 8d is raised and the spot welding gun 3 is rotated clockwise, the workpiece 5 is transferred by the industrial robot 1 to the workpiece delivery section 4 along the circumference. The welding equipment is then transported out of the main welding equipment. Then, a new workpiece 5 is transferred by the industrial robot 1 from the workpiece loading section 2 to the spot welding gun 3, and the welding operation is performed again.

As described above, in the present embodiment, the spot welding gun 3 is rotatably attached to the support column 11a, and after the spot welding gun 3 is rotated by the cylinder 16 until its fixed electrode 9b comes into contact with the workpiece 5, Since the movable electrode 8d is lowered, the workpiece 5
Since the structure of the device can be prevented from deformation and does not require a sliding mechanism unlike conventional devices, the structure of the device can be extremely simplified.

In addition, the heavy spot welding gun 3 is made stationary so that the workpiece 5 is inserted between the electrodes 8d and 9b, which reduces welding time and allows the industrial robot 1 to move the workpiece 5 around a certain circumference. Since the workpiece is transported along the workpiece 5, there is no need to provide a separate transport device for the workpiece 5, and there is no need to provide a workpiece positioning jig in the spot welding gun 3, so that the cost of the apparatus can be reduced.

As described above, according to the welding apparatus according to the present invention, the welding object loading section, the welding object unloading section, and the spot welding gun 8 are arranged on the circumference around one point,
The workpiece is held at the center of the circumference by the workpiece holding part, and the workpiece is held between the workpiece carrying-in part and the spot welding gun, and between the spot welding gun and the welding workpiece carrying-out part. a gun arm having a first end and a second end, and an industrial robot that moves back and forth between the spot welding gun and the gun arm, and is fixed to the spot welding gun so as to be opposite to each other. An electrode and a movable electrode are attached, the base of the gun arm is rotatably supported on a stationary stand, and the object to be welded is inserted between the spot welding gun and the stationary stand and between the fixed and movable electrodes. A rotary drive mechanism is provided to rotate the spot welding gun so that the fixed electrode is in contact with the spot welding gun, so it is possible to prevent deformation of the workpiece with a simple structure without increasing costs, shorten welding time and improve welding efficiency. There is an effect that can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a welding apparatus according to an embodiment of the present invention, and FIG. 2 is a partially sectional side view of a spot welding gun portion of the above embodiment. DESCRIPTION OF SYMBOLS 1... Industrial robot, 1c... Welding object holding part (work setting jig), 2... Welding object carrying part, 3...
Spot welding gun, 5... object to be welded (work), 7
...gun arm, 7a...base, 7d...first end (tip of upper arm), 7f...second end (tip of lower arm), 8d...movable electrode, 9b...fixed electrode, 11...stationary stand, 16... Rotation drive mechanism (air cylinder).

Claims (1)

[Claims] 1. The welding object carrying-in section, the welding object carrying-out section, and the spot welding gun are arranged on a circumference centered on one point, an industrial robot is arranged at the center of the circumference, and the tip of the industrial robot is arranged at the center of the circumference. The part is provided with a workpiece holding part that holds the workpiece and moves back and forth between the workpiece loading part and the spot welding gun and between the spot welding gun and the welding workpiece unloading part, and The spot welding gun has a gun arm having first and second ends, a fixed electrode and a movable electrode provided opposite to each other at the first and second ends of the gun arm, and the base of the gun arm is fixed. The spot welding gun is rotatably supported on a stand, and is inserted between the fixed and movable electrodes between the spot welding gun and the stationary stand, and the spot welding gun is rotated so that the fixed electrode comes into contact with the workpiece to be welded. A welding device characterized in that it is provided with a rotational drive mechanism that causes the welding to occur.