JPS6331309B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spot welding device with an approach device.

For example, as a spot welding apparatus with an approach device used in the assembly process of automobiles, a structure shown in FIG. 1 is known. This is exemplified by a spot welding device for welding a side sill W which is a body side component as a panel work, and 1 is an X-shaped spot welding gun, and this spot welding gun 1 has a pair of gun arms 2a and 2b.
and an air cylinder 3 as an actuator for opening and closing these gun arms 2a, 2b.
and a bracket 4. Reference numeral 6 denotes a lifter plate of the approach device 5 that supports the spot welding gun 1, and the lifter plate 6 is guided to the guide bars 9, 9 by actuation of an actuator, for example, an air cylinder 8, provided on the base 7. It has been moved up and down.

That is, when the spot welding gun 1 is raised together with the lifter plate 6 by the operation of the air cylinder 8, and the limit switch 10 detects that the spot welding gun 1 has reached the predetermined approach limit position, the control device 11 activates the welding gun 1 via the code 13. The air cylinder 3 is actuated by receiving the signal and sending the signal to the valve 12 via the cord 14. This causes the gun arms 2a and 2b to pressurize the side sill W.
It is clamped and spot welded.

When the number of spot welding points is large, a plurality of the above-mentioned devices are installed in parallel, and these devices are operated all at once.

However, in the conventional spot welding equipment described above, the actuator for approach operation and the actuator for opening/closing the gun are separate and independent, so two drive control circuits using hydraulic and pneumatic pressure are provided for them. There is a need. In addition, it is necessary to adopt a control method that pressurizes the welding gun after waiting for a signal indicating that the approach operation is completed, and for this purpose, it is necessary to install an electrical timing control circuit centered on the limit switch mentioned above. However, there was a problem in that the takt time was also relatively long.

In particular, the complexity of the device and the rise in equipment costs due to the provision of the oil/pneumatic drive control circuit and timing control circuit become more pronounced as the number of welding devices installed increases.

In view of the above points, it is an object of this invention to solve the above problems by sharing one actuator for approach and unapproach operations of a spot welding gun and for opening/closing operations of the gun itself. shall be.

That is, in the present invention, in order to achieve the above object, only one actuator is used, and by moving the actuating rod of the actuator forward, the spot welding gun is approached to a predetermined approach limit position with the gun arm in an open state, and the spot welding gun is moved forward. The present invention is characterized in that, as the actuating rod of the actuator continues to move forward, the actuating rod and the gun arm approach each other and the gun arm closes.

Hereinafter, more specific embodiments of the present invention will be described based on the drawings.

FIGS. 2 to 4 are diagrams showing an embodiment of the present invention. The spot welding apparatus shown in the figure is roughly divided into an X-shaped spot welding gun 20 and a floating type base unit 21 that supports this spot welding gun 20.

22 is the base of the base unit 21, and a bracket 23 on the base 22 rotatably supports a trunnion type air cylinder 24 as an actuator. A horizontal holder plate 25 is provided on the upper end surface of the air cylinder 24.
are integrated. Here, the air cylinder 24 is commonly used for both the approach and unapproach operations of the spot welding gun 20 and the opening and closing operations of the spot welding gun 20 itself, as will be described later.

Two guide rods 27 each having a coil spring 26 fitted thereon are rotatably erected on the base 22 via separate brackets 28 and hinge pins 29. On the other hand, movable pieces 32 are rotatably attached to the upper part of the guide rod 27 via a bracket 30 and a hinge pin 31 provided on the lower surface of the holder plate 25, and these movable pieces 32 are attached to the coil spring 2.
6 are slidably inserted into the guide rod 27 as seats for each.

That is, the guide rod 27 and the bracket 2
8, the bracket 30 and the movable piece 32 are respectively rotatable relative to each other, and the guide rod 27 and the movable piece 32 are movable relative to each other. It is elastically supported in a balanced and horizontal manner by force. and,
Only when an excessive external force is applied, air cylinder 2
The structure is such that the holder plate 25 can float around the rotating shaft 33 of No. 4 as the center of rotation.

Reference numeral 34 denotes a substantially U-shaped holder that is disposed above the holder plate 25 and directly supports the spot welding gun 20. This holder 34 has two guide members erected on the holder plate 25. vertical movement along the guide bar 35 as
In other words, it is now possible to perform approach and unapproach movements. Nuts 36 as stoppers for determining the upper limit position of the holder 34, that is, the approach limit position, are attached to the tips of the guide bars 35, respectively.

A piston rod 37 is driven by the air cylinder 24 as an operating rod. This piston rod 37 penetrates the holder plate 25 and enters a push 38 in the center of the holder 34, and a clevis 39 is integrally connected to the tip of the piston rod 37. ing.

Reference numeral 40 denotes a hinge pin horizontally suspended on the holder 34, which includes pins 40d at both ends and a C-shaped retaining ring 40 for the shaft.
It is fixed to the holder 34 by C. or,
A pair of gun arms 41a and 41b of the spot welding gun 20 are attached to the holder 34 on this hinge pin 40.
Gun arm 41 via collar 40e between
Hinge 40a, 4 provided on each of a, 41b
It is rotatably supported by 0b. A pair of links 4 are provided at the lower ends of each of the gun arms 41a and 41b via hinge pins 42, respectively.
3 and 44 are connected, and the other ends of these links 43 and 44 are connected to the clevis 39 via a hinge pin 45. In other words,
The links 43, 44 and the clevis 39 constitute a toggle mechanism, and between the clevis 39 and the hinge pin 40 are the gun arms 41a, 41.
A coil spring 46 is interposed as an elastic body that biases the arms 41a and 41b in the opening direction.
are designed to open and close each other.

Here, the operation of the spot welding apparatus configured as above will be explained.

First, in FIGS. 2 and 4, the holder 34 is shown in the upper limit position, that is, in the approach limit position, and the gun arms 41a and 41b are closed and pressurized, but the holder 34 is in the lower limit position. Gun arm 41 if it is in position
a and 41b are open to each other.

When the air cylinder 24 is actuated to move the piston rod 37 forward from a state where the holder 34 is at the lower limit position, a coil spring 46 is interposed between the clevis 39 at the tip of the piston rod 37 and the hinge pin 40. Therefore, until the holder 34 hits the nut 36, the clevis 39 and the holder 34 do not move relative to each other due to the repulsive force of the coil spring 46, and therefore the gun arm 41
a, 41b do not move at all, and the holder 34
The whole moves up and approaches.

Thereafter, when the holder 34 hits the nut 36, the movement of the holder 34 is stopped, but the piston rod 37 of the air cylinder 24 continues to move forward. Then, from the time when the holder 34 and nut 36 contact each other, the clevis 39 and the holder 34 begin to move relative to each other against the coil spring 46, the piston rod 37 and the gun arms 41a, 41b approach each other, and the link 43 ,44
The gun arms 41a and 41b mutually close each other to press and clamp the panel work W. At this time, if the relative positioning accuracy between the panel work W and the spot welding gun 20 is insufficient and a positional deviation occurs, the entire holder plate 25 described above floats to absorb the amount of deviation. This is done so that the panel work W is not damaged. Then, spot welding is performed under the above-mentioned pressurized conditions.

On the other hand, when the spot welding is completed, the air cylinder 24 operates in reverse, the gun arms 41a and 41b open due to the repulsive force of the coil spring 46, and the holder 34 moves in an unapproach manner due to the action of the air cylinder 24 to reach the lowering limit. Stop at a position.

In other words, according to the embodiment described above, the approach and unapproach operations of the spot welding gun 20 and the opening and closing operations of the gun itself are performed continuously by one shared air cylinder 24.

Further, if it becomes necessary to change the approach stroke based on a change in the panel work W, etc., this can be easily done by simply adjusting the position of the nut 36 as a stopper. Although an air cylinder is used as the actuator 24 in the embodiment of the present invention, the same effect can be obtained by providing a rack on the operating rod and driving this rack with a pinion rotated by an electric motor.

As is clear from the above description, according to the present invention, one actuator is substantially used in common for the approach and unapproach operations of the spot welding gun and for the opening and closing operations of the gun itself. The hydraulic and pneumatic drive control circuits that required two systems can be combined into one system, and the timing control circuit that was previously required can be eliminated, contributing to the simplification of the entire device and the reduction of equipment costs. be able to.

Furthermore, since a timing control circuit is not required, takt time can be shortened.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of a conventional spot welding device with an approach device, FIG. 2 is an explanatory diagram showing an embodiment of the spot welding device with an approach device according to the present invention, and FIG. FIG. 4 is a sectional view taken along the line --- in FIG. 2 as well. 24...Air cylinder (actuator), 34
...Holder, 35...Guide bar (guide member),
36... Nut (stopper), 37... Piston rod (operating rod), 39... Clevis, 40... Hinge pin, 40a, 40b... Hinge, 40c... C-type retaining ring for shaft, 40d... Pin, 40e... Collar,
41a, 41b...gun arm, 43, 44...link, 46...coil spring (elastic body).

Claims (1)

[Claims] 1 Approach the panel work W along the guide member 35. A holder 34 provided to be unapproachable, a pair of gun arms 41a and 41b pivotally supported by the holder 34 so as to be openable and closable,
An actuation rod 37 is movable relative to the holder 34, and one end is connected to the gun arms 41a, 41b so that the gun arms 41a, 41b close when the actuation rod 37 and the pair of gun arms 41a, 41b approach each other. 41b, and the other end is connected to the actuating rod 37.
, an elastic body 46 that always urges the gun arms 41a and 41b in the open direction, a stopper 36 that sets the approach limit of the holder 34, and a stopper 36 that sets the approach limit of the holder 34 when the actuating rod 37 is 1. A spot welding apparatus with an approach device, comprising an actuator 24 that moves the spot welding device forward until it reaches the limit and approaches the gun arms 41a and 41b, and moves it back until the holder 34 comes out of approach.