JPH0825028B2 - Welding gun opening / closing cylinder device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention switches the opening of a welding gun.
The present invention relates to an opening / closing cylinder device that can be obtained .

[0002]

2. Description of the Related Art Conventionally, when a large number of welding guns are mounted on a jig body such as a welding jig for an automobile body shown in Japanese Patent Publication No. 61-57116, one transformer for each welding gun. Since the cost increases due to the provision of one transformer, one transformer is shared by a plurality of welding guns. In this case, if the welding guns are closed at the same time to perform welding, the capacity of the transformer is insufficient. It is common practice to weld a work piece by sequentially closing the welding gun according to a predetermined welding order.

[0003]

When a plurality of welding guns are sequentially closed to weld a workpiece as described above, it is desirable to shorten the time required for the closing operation of the welding gun in order to shorten the cycle time. However, if the closing speed of the gun arm is increased, the gun arm vigorously collides with the work, the impact is increased, and the durability is reduced, so the closing speed can not be increased so much . In this case, the welding gun with the second highest welding order
If you switch from full open to half open in advance,
When the closing operation is required without increasing the arm closing speed
Although the time can be shortened, the opening of the welding gun can be switched for that purpose.
It is necessary to be able to obtain it. In view of the above points, the present invention is designed to open an existing welding gun whose opening cannot be switched.
It is an object of the present invention to provide an opening / closing cylinder device for a welding gun which can be easily modified into a replaceable one .

[0004]

In order to achieve the above object,
The cylinder device of the present invention is configured as follows.

That is, at the tail end of the main cylinder that houses the main piston connected to the gun arm of the welding gun, there is a partition wall that closes the tail end portion of the main cylinder, and a sub cylinder that houses the sub piston behind the partition wall. And the piston rod of the sub-piston is projected into the main cylinder through the partition wall, and a stopper portion facing the main piston is provided at the tip of the piston rod. The welding gun can be switched between the fully open state and the half open state by switching to the step.

[0006]

According to the opening / closing cylinder device of the present invention, the welding gun can be switched between the fully opened state and the half opened state by advancing and retracting the auxiliary piston, and the structure is such that the opening / closing cylinder normally used for the welding gun is the main cylinder. As a result, it suffices to connect the sub-cylinder to the tail end of the cylinder instead of the end cover, and the existing welding gun can be easily remodeled to a switchable opening .

[0007]

EXAMPLES Referring to FIG. 1, 1 is a jig body of a welding jig,
Reference numeral 2 denotes a welding gun mounted on the jig body 1. The welding gun 2 is provided with a gun body 4 having a vertically extending two-plate structure with an opening / closing cylinder device 3 attached to a lower end thereof.
The fixed gun arm 5 is fixed to the gun main body 4, and an arm holder 7 that engages with a cam groove 6 formed in the gun body 4 via a pair of upper and lower guide rollers 7a is provided, and the holder 7 faces the fixed gun arm 5. An upper movable gun arm 8 is attached, an upper end of a piston rod 9 extending from the opening / closing cylinder device 3 is pivotally attached to the holder 7, and the movable gun arm 8 is guided by the cam groove 6 by the vertical movement of the piston rod 9. It is openable and closable between a fully open state shown by A and a closed state shown by C. When the movable gun arm 8 is closed and the work W is sandwiched between the fixed gun arm 5 and the kickless cable 10 connected to the transformer. Relay from the fixed gun arm 5 via the power supply plate 12 attached to the gun body 4 from one terminal plate 10a via the insulating plate 11 and the other terminal plate 10b of the cable 10. To power the movable gun arm 8 through the wood 13 and ounce copper plate 14, and to perform welding of the workpiece W. Further, the gun body 4 is supported by a vertical guide bar 15a attached to a bracket 15 fixed to the jig body 1 so as to be vertically movable by a sleeve 16 formed in the cylinder device 3, and is movable by the upward movement of the piston rod 9. When the gun arm 8 is fully opened, the stepped portion 9a formed at the intermediate portion of the piston rod 9 abuts on the stopper 15b fixed to the bracket 15, and thereafter the gun body 4 moves downward by the abutment reaction force. The fixed gun arm 5 is detached below the work W.

A large number of welding guns are mounted on the welding jig. These welding guns are divided into a plurality of sets addressed to a plurality of sets, one transformer is provided for each set, and a plurality of weldings of each set are provided. The gun was welded by sequentially closing the gun in accordance with a predetermined welding order.

The welding gun 2 shown in FIG. 1 has a second welding order, and the welding gun 2 is in the fully open state indicated by A in the drawing and in the state B.
The open / close cylinder device 3 is configured as follows so that it can be switched to the half open state (state shown by the solid line) indicated by. That is,
The cylinder device 3 is composed of a main cylinder 17 which is an opening / closing cylinder normally used for welding guns, and a sub-cylinder 18 in which a tail end or a lower end of the main cylinder 17 is connected by removing an end cover of the cylinder 17. Main cylinder 1
7, a main piston 19 connected to the piston rod 9
And a partition wall 18a for closing the lower end of the main cylinder 17 is formed in the sub cylinder 18 and the partition wall 18a
The sub-piston 20 is inserted in the lower portion, the piston rod 20a of the sub-piston 20 is projected into the main cylinder 17 through the partition wall 18a, and the stopper portion 20b facing the main piston 19 is provided at the upper end of the piston rod 20a. Provided. The open / close cylinder device 3 includes a first pressure chamber 21 _{1 above} the main piston 19 and a partition wall 18 below the main piston 19.
a between the second pressure chamber 21 ₂ and the third pressure chamber 21 ₃ between the sub piston 20 below the partition wall 18 a, and the end cover 18 at the lower end of the sub cylinder 18 below the sub piston 20.
and a fourth pressure chamber 21 ₄ is provided between
When the main piston 19 is moved upward by supplying air to the pressure chamber 21 ₂ , the welding gun 2 is fully opened and the fourth pressure chamber 2
1 in a state where the auxiliary piston 20 is moved upward by the air supply to the ₄ by supplying air to the first pressure chamber 21 ₁ main piston 19
When the main piston 19 is moved downward, the downward movement of the main piston 19 is stopped halfway by the stopper portion 20b and the welding gun 2 is in a half-open state. In this state, when the air in the fourth pressure chamber 21 ₄ is exhausted, the main piston 19 pushes down the sub piston 20 and moves downward so that the welding gun 2 is closed.

Next, an air circuit for the opening / closing cylinder device 3 will be described with reference to FIG. In the drawing, 22 is a clamp passage connected to an operating air circuit for a work clamper provided in a welding jig, 23 is a pressurizing passage for closing the welding gun, and 24 is an opening passage for opening the welding gun. The first pressure chamber 21 ₁ via the valve 25 ₁ and the shuttle valve 26
And the fourth pressure chamber 21 ₄ via the second switching valve 25 ₂ and the pressurizing passage 23 through the shuttle valve 26 to the first pressure chamber 21 ₁ and the open passage 24 through the third switching valve. It is connected to the second pressure chamber 21 ₂ via 25 _3, and the third pressure chamber 21 ₃ is always open to the atmosphere via the exhaust pipe 27. Where the first
The switching valve 25 ₁ is switched to the closed position after a set time by the air pressure gradually acting from the clamp passage 22 via the delay means 28 such as a delay valve, or the second switching valve 25 ₂ and the third switching valve 25 ₁ . 25 ₃ is configured to be switched to the closing side by the air pressure in the pressurizing passage 23 and the clamp passage 22, respectively. Air is always supplied to the open passage 24.

Next, to explain the operation of the above embodiment, when all the welding guns are fully opened and the work is set on the welding jig, the work clamper is closed and the work is clamped. Air is supplied to the first pressure chamber 21 ₁ via the switching valve 25 ₁ and the shuttle valve 26 and to the fourth pressure chamber 21 ₄ via the second switching valve 25 ₂ and the third switching valve 25 ₃ Is closed and the second pressure chamber 21 ₂ is opened to the atmosphere, the main piston 19 is moved downward while the sub piston 20 is moved upward, and the welding gun 2 having a lower welding order is switched from the fully opened state to the half opened state. To be On the other hand, the welding gun in the front of the welding order is closed immediately after clamping the work, and in this state, the transformer is energized to weld the corresponding portion of the work by the front welding gun. Next, the front welding gun is opened and the pressure passage 2 of the rear welding gun 2 is opened.
Pour air into 3. According to this, air is supplied to the first pressure chamber 21 ₁ via the shuttle valve 26, the second switching valve 25 ₂ is closed and the fourth pressure chamber 21 ₄ is opened to the atmosphere, and the main piston 19 is The auxiliary piston 20 is pushed down and moved downward to close the rear welding gun 2. In this state, the transformer is energized again to weld the corresponding portion of the work.
Here, since the rear welding gun 2 is switched to the half-open state in advance, it can be closed in a short time without increasing the closing speed, and the cycle time can be shortened. When the welding by the rear welding gun 2 is completed, the air supply from the pressurizing passage 23 is stopped, and in this case, the second switching valve 25 ₂ returns to the open position, and the second passage from the clamp passage 22 is switched. Air is supplied to the fourth pressure chamber 21 ₄ via the valve 25 ₂ , the auxiliary piston 20 moves upward, the main piston 19 is pushed up, and the welding gun 2 at the rear is opened in a half-open state. Incidentally, the delay means 28
Is configured to switch the first switching valve 25 ₁ to the closed position after starting the pressurization of the welding gun 2 with the air from the pressurizing passage 23, and when the main piston 19 is pushed up, the first pressure chamber Air is not supplied to the 21 ₁ from the clamp passage 22. When welding with all the welding guns is completed, the air supply to the clamp passage 22 is stopped in order to unclamp the work clamper. According to this,
The third switching valve 25 ₃ returns to the open position, air is supplied from the opening passage 24 to the second pressure chamber 21 ₂ through the third switching valve 25 ₃ , and the main piston 19 further moves upward to perform welding. Gun 2 is fully opened.

In the above embodiment, the air pressure in the clamp passage 22 is made to act on the first switching valve 25 ₁ via the delay means 28. However, as in the embodiment shown in FIG. 3, the first switching valve 25 ₁ is operated. 25 ₁ interposed a fourth switching valve 25 ₄ in the passage for applying a pneumatic pressure of normally-closed clamping passage 22, the fourth switching valve 25 ₄ air pressure clamps passage 22 via the delay means 28 to act, the fourth switch valve 25 ₄ is switched to the open position by the action of the air pressure of the first switching valve 25 ₁ in the clamping passages 22, and to switch to the closed position said first switching valve 25 ₁ after the setting time has elapsed May be. The other structure of the embodiment of FIG. 3 is the same as that of the embodiment of FIG.

[0013]

As is apparent from the above description, the present invention
According to the method, the welding gun whose opening cannot be switched can be easily modified into a gun whose opening can be switched , and the existing equipment can be effectively used.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an example of a welding gun including a cylinder device of the present invention.

FIG. 2 is a diagram showing an example of an air circuit of the cylinder device.

FIG. 3 is a diagram showing another embodiment of the air circuit.

[Explanation of symbols]

2 Welding gun 3 Open / close cylinder device 17
Main cylinder 18 Sub cylinder 18a Partition wall 1
9 main piston 20 sub-piston 20a piston rod 20
b Stopper

Front page continuation (72) Inventor Toshinobu Fujita Takahagi, Hidaka-cho, Iruma-gun, Saitama 427-2 (56) Reference JP-A-2-290680 (JP, A)

Claims (1)

[Claims] 1. A cylinder device for opening and closing a welding gun, the main cylinder having a main piston connected to a gun arm of the welding gun, having a partition wall at the tail end for closing the tail end portion of the main cylinder. A sub-cylinder containing a sub-piston is connected to the tail of the partition wall, the piston rod of the sub-piston is projected into the main cylinder through the partition wall, and a stopper portion facing the main piston is provided at the tip of the piston rod. An opening / closing cylinder device for a welding gun, characterized in that the movement stroke of the main piston is switched between large and small stages by advancing and retreating to allow the welding gun to be switched between a fully open state and a half open state.