JPH07308783A - Method and device for mounting/demounting of electrode holder - Google Patents

Abstract

PURPOSE:To make quick change possible as the taper of an electrode holder is used for guide by making the connecting part between a gun arm and electrode holder-engagement and actuating a cam in the prescribed motion at connecting part. CONSTITUTION:When an electrode holder 9, 10 is changed from the state that an annular recessed face 30 of cams 17, 18 is clamped/held on the outer circumferential face of a holder pin 19 with friction force due to wedge action, a spot welding gun is moved to the prescribed electrode holder changing position by a robot. Levers 15, 16 are driven up to the prescribed angle by driving sources 13, 14 of a cylinder, etc., the annular recessed face 30 of cams 17, 18 are released from the holder pins 19, 20. Successively, a robot catches a flange part 25 for drawing out electrode holders 9, 10 by a placing table of holder to release. After it is drawn, a new electrode holder is inserted in gun arms 7, 8, by oscillating the levers 15, 16 by the driving sources 13, 14 like a cylinder, etc., the cam annular recessed face 30 is fixed to the holder pins 19, 20 with wedge action applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for attaching / detaching and replacing an electrode holder of a spot welding gun.

[0002]

2. Description of the Related Art Conventionally, when spot welding is performed by an industrial robot, the robot is selected from a plurality of spot welding guns and the robot is changed over. In this case, generally, a method has been adopted in which the entire gun is attached and detached and replaced by a gun changer attached to the robot arm.

For example, Japanese Patent Publication No.
Devices such as those disclosed in Japanese Patent Publication No. 79112 and Japanese Patent Publication No. 3-79112 are known.

However, the conventional method of replacing the entire gun requires the welding power source necessary for the function of the gun.
Since the control power source and the cooling water IN and OUT must be separated and combined at the same time, the mechanism tends to be complicated and large. In addition, since the external dimensions of the ganche charger are large and heavy, the proportion of the robot's portable weight becomes larger than the gun's weight.

[0005] In addition, the prior art tended to become really costly to entirely replace the entire gun. Especially when considering the cost of gun products such as electric pressurization type motor guns, it is expensive to install a large number of replacement guns as spares. For this reason, the range of selection of various guns is limited.

Further, in the conventional case, since the gun body and the stand are too large to be placed in the immediate vicinity of the hitting position, the robot moves to a predetermined position for exchanging the gun, resulting in a long loss time.

According to the method of the present invention, the height, depth, and depth can be improved by replacing the parts of the electrode holder only, without changing the entire gun.
The electrode shape can be selected according to the workability, and if combined with a motor gun, it can be used for high-speed welding work on a variety of workpieces.

[0008]

The problem to be solved by the present invention is to take advantage of the fact that when the motor gun becomes widespread, one of the features of the motor gun, that is, the ability to quickly make a dot, the shape of the electrode and the depth of the pocket are taken into consideration. It is necessary to remove restrictions such as. Also, the motor gun itself is expensive, and the cost of a spare gun for replacement is high. Also, in order to shorten the replacement time, it is not possible to line up the replacement guns directly next to the hitting point by the conventional method of changing the gun body together.

Therefore, the present invention has developed an electrode holder attachment / detachment exchange method and device which allows quick exchange because there is no power contactor or the like, so there is no coupling spigot and the tapered portion of the electrode holder serves as a guide.

[0010]

According to the present invention, a connecting portion between a gun arm and an electrode holder is fitted to each other, a cam provided at the connecting portion can be operated in a predetermined manner, and the cam is operated in a predetermined manner at the connecting portion. Thus, there is provided a method for attaching / detaching and replacing the electrode holder of the spot welding gun, wherein the rear portion of the electrode holder is clamped or unclamped by the force of wedge action.

Further, as a device for carrying out the method of the present invention, in a spot welding gun having a gun arm and an electrode holder inserted into the gun arm, the insertion portion of the gun arm and the electrode holder is formed into a tapered fitting, An electrode provided with a holder pin that crosses the axis of the holder at a right angle to the axis of the electrode holder, and a rotatable cam on the gun arm side so that the holder pin can be clamped by the force of the wedge at the insertion position. A holder attachment / detachment exchange device is provided.

[0012]

[Operation] Then, in the present invention, when the electrode holder is replaced, when the cam is rotated to a predetermined angle by using the drive device, the force in the pulling direction, which is now related to the annular concave surface of the cam, is applied from the outer circumference of the holder pin. This allows the electrode holder to be easily removed from the connection part of the gun arm. After removing the previous electrode holder, insert a new electrode holder, operate the cylinder, swing the lever, and rotate the cam to the specified position.
The holder pin is securely fixed at the fitting portion by exerting a pressing force by the wedge action between the annular concave surface of the cam and the holder pin.

As a result, when the spot welding is quickly performed by the servo gun by an automatic device such as an industrial robot, the welding can be performed without being restricted by the shape of the electrode, the depth of the pocket, etc. Also, since the entire gun is not replaced as in the conventional case, the cost of the replacement gun is low. Also, in order to shorten the replacement time, it is not necessary to replace each gun body individually, so it is not necessary to place spare guns side by side in the vicinity of the hitting point.
Also, it does not require a joint such as a power contactor,
In addition, since the tapered portion of the holder serves as a guide, it is possible to replace the holder quickly. Further, according to the device of the present invention, it is possible to form a structural unit and realize cost reduction.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall outline view of a spot welding gun having an electrode holder attachment / detachment exchange device. FIG. 2 is a cross-sectional view of an essential part showing an embodiment of the device of the present invention. FIG. 3 shows the X of the device of the present invention.
It is a -X sectional view. FIG. 4 is a schematic perspective view showing the coupling relationship between the cam and the holder pin provided on the electrode holder when the gun arm is omitted.

In the figure, 1 indicates a spot welding robot gun. Reference numerals 2 and 3 denote arm bodies that open and close with respect to the gun bracket 4 attached to the tip of the arm of the robot about the main shaft 5. Reference numeral 6 is a pressure cylinder or an electric motor, which serves as a drive source for the arm body. Gun arms 7 and 8 are supported by the arm body. 9 and 1
Reference numeral 0 is an electrode holder which is fitted and coupled to the gun arm. The coupling portion 11 and the coupling portion 12 have tapered portions which are engaged with each other as shown in the cross section, and the clamping force is exerted by the action of the wedge force. It is designed to double.

The tapered surface of the fitting portion has a structure in which air such as a cylinder is used to blow off foreign matter that has entered the fitting portion.

Reference numerals 13 and 14 denote drive sources such as air cylinders or motors swingably connected to the gun arm 7 and the gun arm 8, respectively, and a cylindrical cam by a lever 15 and a lever 16 which are moved by the drive sources. The cam 17 and the cam 18 can rotate integrally with a hinge pin 29 that is swingably supported by the gun arm via a bearing 28. Reference numerals 19 and 20 denote holder pins. The holder pin 19 and the holder pin 20 project from both sides in the state of penetrating the small diameter cylindrical portion 27 behind the electrode holder,
The holder pin is engaged with the annular concave surface 30 of the cam that is slightly eccentric with the axial center of the hinge pin 29.

The embodiment of FIGS. 5 to 6 is a schematic view showing the relationship between the cam and the holder pin at the time of clamping and opening,
The shaded portions of the cams 17 and 18 indicate wedge-shaped portions having an annular concave surface. That By axial center P ₁ of the cam eccentric with respect to the axis P ₂ of the hinge pin 29, the drive source 13 and the driving source 14 such as a cylinder swings each lever 15 and 16 back and forth, the cam 17 and The wedge surface of the annular concave surface 30 of the cam 18 is dislocated from the outer circumference of the holder pin 19 and the holder pin 20, or the holder pins 19 and 20 are broken by the frictional force due to the wedge action.
Is drawn in. As a result, the height, depth, and electrode shape can be freely selected by replacing the parts of the electrode holders 9 and 10, and when combined with a motor gun, various guns can be used for various types of workpieces. It was made possible.

Reference numerals 21 and 22 denote IN and OUT provided in the electrode portions of the gun arms 7 and 8 and the electrode holders 9 and 10.
In the cooling water passage, the stop valves 23 and 24 are interposed in the parts 11 and 12 to be connected, respectively, to prevent water leakage at the time of connecting the connecting parts when the electrode holders 9 and 10 are detached and replaced. It works.

Numerals 25 and 26 are projecting flanges provided on the outer periphery of the electrode holder, and the projections are hooked on a holder holder (not shown) so that the electrode holder can be removed.

The operation of the present invention will be described below. When replacing the electrode holders 9 and 10 from the state where the annular concave surfaces 30 of the cams 17 and 18 are now firmly clamped to the outer peripheral surface of the holder pin 19 by the frictional force due to the wedge action, the robot uses the spot welding gun for the predetermined electrode holder. Move to the exchange position.

When the levers 15 and 16 are driven to a predetermined angle by the drive sources 13 and 14 such as cylinders, the cam 1
The wedge contact surfaces 7, 7 of the annular concave surface 30 are released from the holder pins 19, 20.

Next, the robot hooks the extraction flange portion 25 of the electrode holders 9 and 10 on the holder table and removes it.

After the removal, a new electrode holder is inserted into the gun arms 7 and 8 and the driving source 13 such as a cylinder is
The levers 15 and 16 are swung by 14 and the annular concave surface 30 of the cam is moved.
Fix the holder pins 19 and 20 with wedges. By doing so, the exchange of various electrode holders is completed as shown in FIG. 1, and the next welding work is started.

The system of the present invention is not limited to the X type spot welding gun typified in the above-mentioned embodiment, and the same operational effect can be obtained even when used in the C type spot welding gun. Needless to say.

[0026]

As described above, according to the method of the present invention, when spot welding is performed quickly with a motor gun by an automatic device such as an industrial robot, welding can be performed without being restricted by the shape of the electrode, the depth of the pocket, and the like. Also, since the entire gun is not replaced as in the conventional case, the cost of the replacement gun is low. In addition, because it is not a conventional method to replace each gun body, there is no need for a large space for lining up the auxiliary guns near the hitting point, and the spare holder can be placed near the hitting point. Is possible. Further, according to the device of the present invention, a joint portion such as a power source contactor is not required, and the tapered portion of the holder serves as a guide, which enables quick replacement. It can also be a structural unit,
Achieve cost reduction.

[Brief description of drawings]

FIG. 1 is an external side view of the entire robot gun showing one embodiment of an apparatus for carrying out the method of the present invention.

FIG. 2 is a cross-sectional view showing the main structure of the device of the present invention.

FIG. 3 is a sectional view taken along line XX of FIG.

FIG. 4 is a cross-sectional view showing the main structure of the device of the present invention.

FIG. 5 is a sectional view showing a state in which the annular concave surface of the cam in the device of the present invention locks the holder pin.

FIG. 6 is a cross-sectional view showing a state in which the annular concave surface of the cam in the device of the present invention opens the holder pin.

[Explanation of symbols]

 1 Robot Gun 2 Arm Main Body 3 Arm Main Body 4 Gun Bracket 5 Spindle 6 Drive Source 7 Gun Arm 8 Gun Arm 9 Electrode Holder 10 Electrode Holder 11 Coupling 12 Coupling 13 Drive Source 14 Drive Source 15 Lever 16 Lever 17 Cam 18 Cam 19 Holder Pin 20 Holder pin 21 Cooling water passage 22 Cooling water passage 23 Stop valve 24 Stop valve 25 Flange portion 29 Hinge pin 30 Annular concave surface

Claims (5)

[Claims] 1. A direction in which a connecting portion between a gun arm and an electrode holder is fitted to allow a cam provided at the connecting portion to perform a predetermined operation, and the rear of the electrode holder is pulled in at the connecting portion by operating the cam. The method of attaching / detaching and replacing the electrode holder of the spot welding gun, in which the holder is unclamped by the reverse operation of this cam. 2. A spot welding gun having a gun arm and an electrode holder inserted into the gun arm, wherein a tapered fitting portion is provided at an insertion portion between the gun arm and the electrode holder, and a holder is provided behind the electrode holder. Providing a holder pin that intersects the axis at a right angle
An electrode holder attachment / detachment exchange device for a spot welding gun, which is provided with a rotatable cam on the gun arm side so that the holder pin is clamped and held at the fitting portion of the electrode holder by the force of the wedge action. 3. The electrode holder attachment / detachment exchange device according to claim 2, wherein the cam is unitized to be rotatable by a drive source such as an air cylinder or a motor. 4. A stopper valve, which is separated or connected to the electrode holder side, is built in the cooling water passage at IN and OUT of the cooling water passage provided in the gun arm, whereby the gun arm and the electrode holder are separated or joined. The electrode holder attachment / detachment exchange device according to claim 2, wherein the cooling water passage is opened / closed at the same time. 5. The electrode holder according to claim 2, wherein an annular concave surface of the cam is engaged with an outer peripheral surface of the holder pin by rotationally driving a cam that is eccentric to a central axis of the holder pin to double the force. Detachable exchange device.