JPH0435016Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a welding device used for spot welding various parts, etc., for example.

[Prior Art] A turntable called an index table, which is used in parts processing and assembly lines, transports the workpiece to a predetermined stage by rotating it in one direction at a predetermined pitch while holding the workpiece. I'm starting to do that. For example, in a spot welding process for pressed products, a workpiece received at the first stage, which is placed halfway in the circumferential direction of the turntable, is moved to the second stage by one pitch rotation of the turntable. After the turntable stops at this second stage, the welding gun and the workpiece are positioned, and immediately after that, spot welding by the welding gun is performed.

[Problems to be solved by the invention] In the conventional device described above, the workpiece simply moves while the turntable rotates between stages, and welding cannot be performed until the turntable stops. . In other words, when it comes to welding, there is a loss of time while the turntable is rotating, which has been a major hindrance to improving processing efficiency.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a welding device that can efficiently perform a welding process by effectively utilizing the time during which the turntable is rotating.

[Means for Solving the Problems] A welding device devised by the present inventor to achieve the above object includes a turntable that has means for holding a workpiece and is rotatable in only one direction; A welding gun mounting base is provided that can be rotated in the same direction as the turntable in synchronization with the turntable, and can also be rotated in the opposite direction. a rotation driving means for returning the welding gun mount to its original position after the welding gun mount has rotated in the above-mentioned one pitch; a welding gun mounted on the welding gun mount; Welding gun drive controlled to move the workpiece held on the turntable to a predetermined welding position and to perform a predetermined welding process while the turntable and welding gun mounting base rotate one pitch. means and
Equipped with:

[Operation] After the workpiece is held by the workpiece holding means on the turntable on the workpiece receiving stage, the turntable is rotated by one pitch by the turning drive means. In this direction of rotation, the turntable and welding gun mount rotate together, and the workpiece moves toward the next stage. During this one-pitch revolution, the welding gun is moved to a predetermined welding position by the welding gun drive means, and the welding process, such as spot welding, is performed by the welding gun. This welding process is completed while the turntable rotates one pitch. When the workpiece has moved to a predetermined stage, the turntable stops, and the swing drive means moves in the opposite direction, causing the welding gun mount to pivot in the opposite direction to the above, returning the welding gun mount to its original position. Return to position. The turntable remains stopped. The moving speed of the welding gun mount when returning (reverse direction) is preferably faster than the moving speed when turning the turntable (forward direction).

[Example] An example of the present invention will be described below with reference to FIGS. 1 and 2.

The multi-spot welding device 1 of this embodiment has a base 2.
The base body 2 is provided with a turntable 4 that rotates around a vertical axis 3. This turntable 4 is configured to be able to rotate only in the direction of arrow _F1 shown in the figure by means of a reversal prevention mechanism 5 incorporating a ratchet mechanism or a one-way clutch. A complicated clamping jig 6 (only a part of which is shown) is provided on the turntable 4 as an example of means for holding the workpiece A. Each clamp jig 6 is arranged according to the arrangement interval of each stage.
They are arranged at equal pitches in the circumferential direction of the turntable 4. As illustrated in FIG.
In this method, a plurality of sheet metal press products are assembled into a predetermined shape by spot welding. In the figure, B indicates the spot dot location.

A welding gun mount 10 is provided on the basic body 2, which pivots about a vertical axis 3. This welding gun mount 10 rotates concentrically around the vertical axis 3 in synchronization with the turntable 4, but unlike the turntable 4, this mount 10 rotates in the opposite direction (arrow
It is also possible to turn in _F2 direction).

The welding gun mounting base 10 is moved in the forward direction (direction of arrow F ₁ ) and in the reverse direction (direction of arrow F ₂ ) by a reciprocating hydraulic cylinder mechanism 11 as an example of a driving means.
The turntable 4 is rotated one pitch at a time. This cylinder mechanism 11
For example, an air cylinder or a hydraulic cylinder is adopted as the rod 1 by means of a fluid circuit 12.
3 is driven in the desired direction and at the desired operating speed.
The fluid circuit 12 is controlled by a controller 15 using a microcomputer or the like.

A welding gun 20 is mounted on a welding gun mounting base 10. This welding gun 20, like a well-known spot welding machine, has a structure that allows a welded part to be held between a pair of electrodes 21 and 22, and a current to be passed between the electrodes 21 and 22. The current 21 can be moved in the axial direction by a current crimping mechanism 23. This welding gun 20 has a lifting base 2
4.

The welding gun 20 is moved to a spot welding point position on the workpiece A by a welding gun driving means 30. This drive means 30 includes a lifting mechanism 3 for moving the welding gun 20 in the vertical direction.
1 and a horizontal movement mechanism 32 for moving the welding gun 20 in the radial direction of the turntable 4, and further includes a mechanism (not shown) for rotating the welding gun 20 around a horizontal axis as necessary. ) may also be provided.

The elevating mechanism 31 includes a guide mechanism 35 using a guide rail or the like that holds the elevating base 24 slidably in the vertical direction, and a servo pulse motor 36.
It is configured to include a lead screw mechanism 37 and the like for converting the rotational force of the motor 36 into the movement of raising and lowering the base 24.

The horizontal movement mechanism 32 includes a guide mechanism 41 using a guide rail or the like that holds the slider 40 movably in the horizontal direction, a servo pulse motor 42, and a servo pulse motor 42 for converting the rotational force of the motor 42 into linear movement of the slider 40. It is configured to include a lead screw mechanism 43 and the like.

The rotation direction, rotation amount, etc. of each motor 36, 42 are controlled by the controller 15, and the controller 15 also controls the energization of the electrodes 21, 22.
5. Therefore, control data corresponding to the spot position of the workpiece A is input into the controller 15 in advance. Incidentally, the spot position may be known by providing a sensor for detecting the type, shape, dimensions, etc. of the workpiece A at an appropriate position on the turntable 4 or the welding gun mounting base 10.

Next, the operation of the welding device 1 having the above configuration will be explained.

When the workpiece A is held by the clamp jig 6 on the workpiece receiving stage, the rod 13 of the cylinder mechanism 11 extends at a desired speed, so that the welding gun mounting base 10 moves by one pitch of the turntable 4 in the direction of arrow _F1. be rotated by. At this time, since the turntable 4 also rotates in synchronization with the welding gun mounting base 10 in the same direction, the workpiece A heads to the next stage (for example, the workpiece removal stage) together with the welding gun 20.

Then, in the middle of the above one-pitch turn,
A welding process is performed using the welding gun 20. That is, the welding gun driving means 30 operates so that the electrodes 21 and 22 of the welding gun 20 come to a predetermined spot position with respect to the workpiece A that is held by the clamp jig 6 and rotates together with the turntable 4. At the same time, the electrodes 21 and 22 are crimped by the crimping mechanism 23 to the part to be welded on the workpiece A, and a predetermined current is supplied to sequentially perform resistance welding at each spot position. After each part is welded in this manner, the turntable 4 and the welding gun mounting base 10 reach the workpiece take-out stage, and the movement of the rod 13 stops and the turntable 4 also stops. Then, the workpiece A is taken out from the clamp jig 6. After that, or before that, the welding gun 20 is retracted by the driving means 30 to a position where it does not interfere with the return of the welding gun mount 10 (a position where it does not interfere with the jig 6).

After the workpiece A is taken out, the cylinder mechanism 11
As the rod 13 moves in the opposite direction to the above, the welding gun mount 10 pivots in the direction of arrow _F2 . The turning speed at this time is several times faster than the turning speed in the direction of arrow _F1 . In this way, for the direction _F2 in which the welding gun mount 10 returns,
Since the turntable 4 is prevented from rotating by the reverse rotation prevention mechanism 5, only the welding gun mounting base 10 is
The turntable 4 rotates in the _F2 direction and remains stopped.

As described above, according to the multi-spot welding apparatus 1 of this embodiment, the welding process can be completed by effectively utilizing the turning time while transferring the workpiece A to the next stage, so that the loss time can be reduced or This is extremely effective in streamlining the process. Since the turntable 4 and the welding gun mounting base 10 can be rotated by one cylinder mechanism 11, the structure is simple. Note that the swing driving means is the cylinder mechanism 11.
Any other suitable drive mechanism may be used. The present invention is also applicable to welding machines other than spot welding.

[Effects of the invention] According to the invention, the welding process can be performed efficiently by effectively utilizing the time during which the turntable is rotating. Moreover, it has a turntable and a welding gun mounting stand.
Since it can be moved by two turning drive means, it can also contribute to the simplification of the structure.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a welding device according to an embodiment of the present invention, and FIG. 2 is a perspective view showing an example of a workpiece and workpiece holding means. A... Workpiece, B... Welding location, 1... Welding device, 4... Turntable, 5... Reverse prevention mechanism, 6... Work holding means, 10... Welding gun mounting base, 11... Rotating Drive means (cylinder mechanism),
15... Controller, 20... Welding gun, 30
...Welding gun drive means.

Claims (1)

[Scope of utility model registration request] a turntable that has means for holding a workpiece and is rotatable in only one direction;
A welding gun mounting base is provided that can be rotated in the same direction as the turntable in synchronization with the turntable, and can also be rotated in the opposite direction. a rotation driving means for returning the welding gun mount to its original position after the welding gun mount has rotated in the above-mentioned one pitch; a welding gun mounted on the welding gun mount; Welding gun drive controlled to move the workpiece held on the turntable to a predetermined welding position and to perform a predetermined welding process while the turntable and welding gun mounting base rotate one pitch. A welding device characterized by comprising: means.