JP3820859B2 - Chip removal device for welding gun - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention relates to a tip removal device for a welding gun that removes an electrode tip when replacing an electrode tip of a spot welder.
[0002]
[Prior art]
In general, spot welding pressurizes stacked workpieces with a pair of tips (pressing force 2000 to 3000 N) to secure a current path. As the number of welding points increases, the tip shape of the tip becomes Due to heat generation and pressure applied by a large current, deformation and wear occur and sufficient welding quality cannot be obtained. Therefore, the welding current is stepped up according to the number of welding points. Further, when the upper limit of the welding current is reached, the production line is stopped and the tip is automatically polished, or it is removed and replaced with a new one or polished one to ensure the tip shape of the tip.
[0003]
By the way, in recent years, chemical treatment materials such as high rust prevention have come to be used for the materials to be welded, and there is a tendency for electrode tips to be worn out and to be replaced more frequently. Does not fit the current situation. In order to change the tip without stopping the production line, it must be performed from the end of the welding operation to the start of the next welding (for example, the workpiece transfer time). However, this time is short and several seconds.
[0004]
Thus, as an automatic electrode tip removal device (exchange device), for example, there is one disclosed in Japanese Patent Laid-Open No. 11-90646. According to this, as shown in FIG. 4, the link mechanism 4 is tilted within a predetermined range by the linear actuator 5 simply by positioning the shank tip 1A of the welding gun with the electrode tip to the clamping center O by the robot arm. As a result, the electrode tip is held between the chuck claws 2A and 2B, and the tip is loosened by rotating the chuck claws 2A and 2B, and is removed from the tip of the shank. Subsequently, the tip supply means 9 is swung together with the support member 3 by the repulsive force of the elastic body 6, and the tip is attached at the clamping center O which is the positioning position. According to the tip detaching device, there is an advantage that it takes less time to move the position of the welding gun because the tip is removed and the tip is attached at the same position.
[0005]
[Problems to be solved by the invention]
However, in the removal of the tip of the method disclosed in Japanese Patent Laid-Open No. 11-90646, if the tip and the tip of the shank are strongly fitted, it may take time for the chuck pawl to rotate. In some cases, the removal of the chip is uncertain.
[0006]
Accordingly, an object of the present invention is to provide an electrode tip removal device for a welding gun that shortens the time required for tip removal.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the invention of claim 1, in a tip removal device for a welding gun for removing a tip fitted to a tip of a shank of a welding gun , a drive unit, a support unit moved by the drive unit, and a support unit A tip supported to be able to tilt and a detachable tool capable of entering the gap between the shank, and the support portion is a pair of guide plates for guiding the detachable tool, and the tip detachable tool is tilted on the guide plate Two pairs of cam holes are provided, and two pairs of cam engagement protrusions are provided on the removal tool, and the two pairs of cam engagement protrusions are respectively engaged with the two pairs of cam holes. The tip removal tool enters the gap between the tip and the shank and tilts due to the reaction force received from the shank neck .
[0008]
According to the structure, with the cam engaging projection of the two pairs provided in the chip removal tool is engaged, the chip removal tool is the drive unit, together with the front Symbol pair of guide plates are moved, the guide plates The chip removal tool supported by the chip enters the gap between the chip and the shank.
[0009]
When the chip removal tool is brought into contact with the shank neck from the shank neck receives a reaction force, so the chip removal tool is tilted, a short moving distance of the chip removal device, the chip is Ri removed preparative.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
(Construction)
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
In the tip removing device, a gap between a shank 19 of a welding gun and a tip 18 fitted to a neck portion 20 of the tip of the shank 19 is provided at the tip of a claw portion 13A of a lever lever 13 which is a tip remover. A U-shaped groove having a U-shape in a plan view that can be inserted into the lever is formed, and the side surface of the lever lever 13 is movably held by two guide plates 14. The guide plate 14 is provided with two cam holes 15. Two cam engaging protrusions 16 formed on the lever lever 13 are engaged so as to be movable in the respective cam holes 15. The lever type lever 13 is tilted by moving the two cam engaging projections 16 in the two cam holes 15, respectively. Further, as shown in FIG. 3A, the lever 13 is pressed against the front end of the cam hole 15 by a spring 38 which is an elastic member. Further, the cam mechanism 17 including the lever lever 13, the guide plate 14 and the spring 38 is assembled to the tip of the piston rod 22 of the air cylinder 21 as a driving means together with the support plate 27. It can reciprocate.
[0011]
The above structure is a pair of upside down structures in order to cope with the exchange of the pair of upper and lower chips 18.
[0012]
(Function)
Next, the operation of the chip removing device will be described.
(Arrival at welding gun fixed position)
When it is necessary to replace the electrode tip, the welding gun (not shown) moves to a fixed position so that the tip 18 is arranged in front of the lever lever 13 by a welding robot (not shown). At this time, the welding gun releases the pressure, and the shank 19 is opened, and the shank 19 is in a separated state (see FIGS. 1 and 3A).
(Tip removal)
The piston rod 22 of the air cylinder 21 moves forward, and as shown in FIGS. 2 and 3B, the tip claw portion 13A of the lever lever 13 attached to the cam mechanism 17 is connected to the shank 19 and the tip 18 of the welding gun. Inserted in the gap between. The base end portion of the tip claw portion 13 </ b> A of the lever lever 13 contacts the neck portion 20 of the shank 19. If the piston rod 22 continues to advance further from that state, the lever lever 13 receives a reaction force from the neck 20 and is urged in a direction opposite to the direction in which the piston rod 22 advances. Then, the engaging protrusion 16 formed on the lever lever 13 moves to the lower right in FIG. 1 in the cam hole 15 against the urging force of the spring 38.
Then, the lever lever 13 tilts, and the tip 18 is twisted while the height of the tip claw portion 13A of the lever lever 13 remains constant. As a result, the tip 18 is removed from the shank 19.
[0013]
In order to lower the temperature of heat generation due to a large current during welding, a flow path of cooling water is provided in the shank 19 and the tip 18, but when the tip 18 is removed, switching from cooling water to air is performed so that the cooling water does not leak. The air pressure change is detected by a sensor to check whether the chip 18 has been removed from the shank 19.
[0014]
(effect)
Next, effects of the present embodiment will be described below.
[0015]
(1) According to the present embodiment, since the lever lever 13 is tilted by the cam mechanism 17 and the removal is performed, the air cylinder 21 is compared with a case where the removal tool only advances, for example, like a wedge type. The travel distance is shorter and the removal time can be shortened.
[0016]
(2) The cam mechanism 17 has a simple structure and is removed, although there is no need for fine adjustment of the pressure for clamping the tip 18 as compared with a structure that rotates by clamping the tip 18 of Japanese Patent Laid-Open No. 11-90646, for example. High certainty.
[0017]
In the present invention, the embodiment is not limited to the above embodiment, and may be modified as follows.
In the embodiment, the detaching device is a pair of upper and lower parts, and the pair of upper and lower chips are removed.
○ In the embodiment, the lever lever as a removal tool is provided with an engaging protrusion, and the guide plate as a support portion is provided with a cam hole, but on the contrary, the lever lever is provided with a cam hole, It is also possible to adopt a structure in which an engaging projection is provided on the guide plate.
【The invention's effect】
According to the first aspect of the present invention, when the chip removing tool comes into contact with the shank neck, the chip removing tool is tilted by receiving a reaction force from the shank neck, so that the chip is removed with a short moving distance of the chip removing device. . It is possible to reduce the time required for chip removal . Removing the good Ri secure chip is possible.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a perspective view of an automatic tip detaching apparatus when a welding gun arrives at a fixed position in an embodiment.
FIG. 2 is a perspective view of the automatic chip removing device at the time of chip removal in the embodiment.
FIG. 3 is a diagram illustrating the operation of a cam mechanism in the embodiment. (B) is when the welding gun arrives at the fixed position, and (b) is when the tip is removed.
FIG. 4 is a perspective view of a chip removal device (exchange device) in the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 13 Lever lever as removal tool, 14 Guide plate as support part, 15 Cam hole, 16, Cam engagement protrusion part, 17 Cam mechanism, 18 chip | tip, 19 Shank, 20 Neck part, 21 Air cylinder as drive part, 22 Piston rod, 38 Spring as an elastic member.

Claims (1)

In a welding gun chip detaching device that removes a chip fitted to a tip of a welding gun shank , a drive unit, a support unit that is moved by the drive unit, and a gap between a tip and a shank supported to be tiltable by the support unit The support plate is a pair of guide plates for guiding the tip removal tool, and the guide plate is provided with two pairs of cam holes so that the tip removal tool tilts. The tip detachment tool is provided with two pairs of cam engaging projections, the two pairs of cam engagement projections are respectively engaged with the two pairs of cam holes, and the tip detachment tool is connected to the tip and the shank. A chip removing device that is tilted by a reaction force that enters a gap and receives from a shank neck .

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