JPS586596B2 - Jiku Kiyudenshikiyou Setsgan - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding gun called a fixture gun for resistance welding, and in particular, it does not have an external connection for power supply, has a power supply mechanism housed inside a pressurized cylinder, and has an axis of the cylinder. The present invention relates to a welding gun using an axial power feeding method that allows welding current to be efficiently fed from the heart to the electrode portion.

In recent years, in various mass production industries including automatic industries, multi-spot welding machines have been rapidly used to automate and speed up spot welding operations.

However, the fixture gun, which is the central part of a multi-spot welding machine, has not yet been functionally sufficient.

The main reason for this is that in order to supply welding current to the electrode tip, the terminals of the welding transformer and the tip of the fixture gun must be externally connected using a thick flexiple secondary cable.

The problems with conventional fixture guns based on this are as follows.

(1) In addition to thick secondary cables, cooling water supply/drainage hoses, and fluid pressure supply/discharge hoses are connected to the fixture/gun, so the wiring and piping near the welds are obscene, so parts cannot be easily removed. Delivery and assembly of parts such as equipment will be hindered.

(2) Due to the above-mentioned piping and wiring, there are significant restrictions on fixture design.

(3) During work, secondary cables are used under harsh conditions such as expansion and contraction, bending, and thermal fatigue due to resistance heat generation, resulting in problems such as cable strands and cable terminal joints breaking and premature wear. , which tends to result in poor welding results.

(4) It is inconvenient for maintenance and inspection.

The present invention effectively supplies welding current from inside the welding gun to the electrode section by using a power supply mechanism provided inside the pressure cylinder of the welding gun, without using an expensive and space-consuming flexible secondary cable. The object of the present invention is to provide a welding gun capable of performing good welding work, to solve all of the above-mentioned problems, and to achieve the above-mentioned demands.

The configuration, functions, and features of the present invention will be summarized below.

The gist of the present invention is to provide a movable piston that slides on the inner wall of the cylinder and forms at least one pressure-side and return-side fluid pressure working chambers, a piston rond that operates integrally with the piston, and a piston rond disposed above the piston rond. L, a floating piston that slides on the piston rod, and a contact that is fitted into the top of the piston rod and whose head is always in contact with the power supply conductive plate, and the contactor has a tapered portion on the outer surface of the lower end thereof. and a plurality of slots for imparting a slight spring action to the male-shaped tapered portion, the inner surface of the tapered portion slidingly connecting with a portion of the piston rod, and the floating piston having: It has a female taper part on its upper part that matches the male taper part, and by supplying fluid pressure to the pressurizing side fluid pressure working chamber, fluid pressure is applied to the lower surface of the floating piston. The tapered portion tightens the male taper portion of the contactor and tightens the inner surface of the tapered portion to the piston rond, so that current from the power supply conductive plate passes through the contactor, the piston rond, and the piston rond. This is a shaft-powered welding gun for spot welding machines that supplies power to the electrode at the lower end of the piston.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an example of the shaft-fed welding gun of the present invention when it is open, and FIG. 2 is a cross-sectional view showing the welding gun shown in FIG. 1 when pressurized, where 1 is a welding gun. The pressurizing cylinder outer cylinder 2 applied to the main body is a movable piston that is held airtight by a seal 3 on the inner wall of the cylinder outer cylinder 1 and slides to a stepped part 4 provided at a predetermined position on the cylinder inner wall. 5 and operate together to form fluid working chambers on the pressure side A and the return side B.

A floating piston 6 is disposed above the stepped portion 4 and the piston rod 5, penetrates into the piston rod 5, slides on its outer wall, and is always pushed downward by the tension of a spring 7. , a female tapered portion 8 is formed on the inner wall of the opening above it.

Reference numeral 9 designates a contactor for supplying power to the piston rod 5, and as shown in detail in FIG. 3, a male taper portion 10 is formed by reducing the outer diameter of the lower end opening in the axial direction. A plurality of axial slots (vertical grooves) 11 are bored at appropriate intervals on the circumference of the piston 10, and are configured to engage with a female taper portion 8 formed on the floating piston 6.

Therefore, when a compressive force is applied between the two, the contactor taper surface 1
0 is tightened so that the contact surface of the contactor 9 can be easily and strongly brought into close contact with the piston rod 5.

Reference numeral 12 denotes a power supply conductive plate on the welding transformer side, which is always in contact with the head of the contactor 9.

The operation of the present invention having the above configuration will be explained.

As can be understood from the attached drawings, FIG. 1 shows a state in which the movable piston 2 is stopped at the end of the retraction stroke, and in this case, the fluid pressure is in the fluid pressure passage S.
Through this, pressure is applied to the return side fluid pressure working chamber B of the cylinder.

On the other hand, the floating piston 6 remains in contact with the stepped portion 4 due to the tension of the spring 7 because the fluid pressure in the pressurizing side fluid pressure working chamber A is released from the fluid pressure passage P and the internal pressure is O. It has been returned to a state.

Therefore, the female taper 8 of the floating piston 6 is pushed back by the spring 7 to a position where it is released from the male taper 10 of the contactor 9.

Next, the state at the time of pressurization is shown in FIG. - Rod 5 is moved to the bottom of the diagram, and eventually,
When the workpiece 14 hits the electrode part 13 attached to the lower end of the piston rod 5, it cannot move anymore, and the floating piston 6 is moved upward by the pressurizing force of the pressure-side fluid pressure working chamber A, and the tension of the spring 7 The male taper 8 of the floating piston engages with the male taper 10 of the contactor 9 against this force.

In connection with the locking operation, a clamping force is also generated on the inner contact surface of the contactor 9 in the radial direction against the piston rod 5, and the piston rod 5 and the contactor 9 are brought into close contact with each other with sufficient pressure.

On the other hand, the pushing up force on the floating piston 6 also pushes up the contactor 9, so that it comes into strong contact with the power supply conductive plate 12.

Therefore, the welding current from the power supply conductive plate 12 is
The contactor 9 → the piston rod 5 → the electrode part 1
Power is effectively supplied to 3.

To release from the above pressurizing operation, fluid pressure is sent from the fluid pressure passage S to the return side fluid pressure working chamber B, as described above in the outline of the operation in Fig. 1, and the movable piston 2 and piston rod 5 are Returning to the original position, the floating piston 6 is moved back by the tension of the spring 7, the pressure applied to the female taper part 8 of the floating piston 6 and the male taper part 10 of the contactor 9 is released, and the piston - The contact pressure of the contactor 9 applied to the rod 5 is released, the engine returns to its starting position, and all functions return to normal.

As described above, by providing a power supply mechanism in the axis of the welding gun, the present invention can effectively supply welding current from the inside of the welding gun to the electrode section, which is expensive and takes up a lot of space, which was previously required. Streamlining the design of multi-spot welding machines by simplifying the overall fixture, improving durability as well as eliminating the need for secondary cables that require
To provide an extremely novel axis-powered welding gun that can greatly contribute to simplification.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of the welding gun according to the present invention when it is open, Fig. 2 is a sectional view similar to Fig. 1 when it is pressurized, and Fig. 3 partially shows the contactor of the power supply mechanism. FIG. [Explanation of symbols in drawings] 1: cylinder, 2: movable piston, 3: seal, 4: stepped part, 5: piston rond,
6: floating piston, 7: spring, 8: female taper part, 9: concuck, 10: male taper part, 11: slot, 12: conductive plate for power supply, 13: electrode part, 14: workpiece.

Claims (1)

[Claims] 1. A movable piston that slides on the inner wall of the cylinder and forms at least one pressure-side and return-side fluid pressure working chambers, a piston rod that operates integrally with the piston, and a piston rod that is disposed above the piston rod, and that is arranged above the piston rod. A contactor is fitted into the top of the piston rod and whose head is always in contact with a conductive plate for power supply, and the contactor has a tapered part and a tapered part on the outer surface of its lower end. The inner surface of the tapered part slides and connects with a part of the piston rod, and the floating piston has a plurality of slots on its upper part to give a slight spring action. By supplying fluid pressure to the pressurizing side fluid pressure working chamber, fluid pressure is applied to the lower surface of the floating piston, so that the female taper part By tightening the male tapered part of the contactor and tightening the inner surface of the tapered part to the piston rod, the current from the power supply conductive plate is passed through the contactor, the piston rod, and the piston rod. A shaft-powered welding gun for spot welders that supplies power to the electrode at the bottom end of the iron.