JP3969682B2 - Lower electrode device for resistance welding - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spot welder having a guide pin for positioning a workpiece on a lower electrode device.
[0002]
[Prior art]
When a panel is set on the lower electrode corresponding to the upper electrode of a spot welder, and a welding nut or bolt is supplied to the welding position and projection welding is performed, a guide pin that protrudes from the electrode tip with a specified dimension is placed on the panel. The workpiece is positioned by inserting it into the positioning hole and the inner diameter of the welding nut.
[0003]
In this case, the guide pin is inserted so as to be movable up and down inside the electrode tip attached to the upper part of the electrode rod of the lower electrode. The movement of the guide pin is used to detect the presence or absence of workpiece supply, and the signal that operates in connection with the movement of the guide pin and the energization signal of the welding current that flows to the electrode are interlocked. Have been used.
[0004]
In general, this type of electrode device penetrates the inside of the electrode rod so that the rod can move in the longitudinal direction, the rod and the guide pin are in contact with each other on the same axis, and supported by the lower portion of the electrode rod. In addition to connecting the members, a detector that detects the movement of the guide pin at a predetermined position of the support member based on the displacement of the movement amount of the rod that operates in association with the guide pin, and the return operation of the guide pin are performed. One having a cylinder is known (= Japanese Utility Model Publication No. 61-16937).
[0005]
In this device, a short electrode holder is mounted on the collar inserted into the guide pin in the screw hole of the electrode rod, and an insulating bush is inserted into a through hole provided in the electrode holder. A guide pin is inserted into the bush, and a cap-shaped electrode tip is inserted into the threaded part formed on the upper outer periphery of the electrode holder, and the tip of the guide pin protrudes from the electrode surface by a specified dimension. is there.
[0006]
In general, a guide pin made of ceramic or a guide pin whose surface is hard anodized or an oxide film such as a ferritic stainless alloy is used.
[0007]
When welding a welding nut (projection nut) to the panel, the guide pin is pushed up by the elevating cylinder when the workpiece is set and inserted into the workpiece positioning hole. Further, when welding the workpiece, the guide pin is pushed down into the electrode tip by the pressing operation of the upper electrode.
[0008]
The guide pin is repeatedly forced to move up and down during workpiece setting and workpiece welding, and is inserted into the guide pin with the workpiece tilted during workpiece setting, or spatter is inserted between the guide pin and the through hole of the electrode tip. The guide pin may not move due to biting, and the surface insulation film of the guide pin may be damaged, or the guide pin itself may be cracked. Therefore, the guide pins are handled as consumables, and the guide pin parts are replaced.
[0009]
[Problems to be solved by the invention]
In the conventional electrode device, when the guide pin is replaced, the mounting structure of the guide pin, the electrode tip, and the electrode holder is complicated. Therefore, if the insulating bush in the electrode holder is not taken out, the guide pin is pulled out. It was difficult to replace the parts.
[0010]
[Means for Solving the Problems]
The present invention provides a lower electrode device that solves the above-mentioned conventional problems.
Specifically, as shown in FIG. 1, the electrode tip 3 is inserted into the electrode rod 2 supported by the arm 1 of the spot welder, and the tip of the guide pin 5 protrudes from the through hole 4 of the electrode tip. An electrode device, wherein an upper end of a guide rod 6 inserted concentrically with an axial center line (YY) of the electrode rod and the guide pin are connected via a joint 13, and a lower end of the guide rod The rod 8 of the lifting / lowering means 7 that operates this is connected via a joint 14, the cylinder and the electrode rod are supported via a bracket 9, and between the bracket and the joint 14 , a stopper means 10 is provided. There have been detachably mounted, the guide pins from the detachable position said stopper means in the mechanism for detaching from the joint of withdrawal the guide rod Downward the free state and without, a shaft axis in the same direction as insertion and removal direction is the electrode rod attached to and detached from the electrode tip, moreover insertion and removal direction of the guide pin 5 with respect to the joint 13 with respect to the axis center line It is a direction that intersects at right angles.
[0011]
[Action]
When replacing the guide pin 5, the guide pin can be removed from the joint 13 simply by pulling the handle of the stopper piece 10, removing the stopper piece from the bracket 9, and removing the electrode tip 3 from the electrode rod 2. Pin replacement work can be performed in a short time.
[0012]
In addition, according to the structure of the present invention, the number of parts of the lower electrode is reduced, and the lower electrode is simplified and reduced in price.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the lower electrode according to the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing the entire structure of the lower electrode device of the present invention.
2 is an AA arrow view, and FIG. 3 is a BB arrow view.
FIG. 4A is a cross-sectional view showing a removed state when the guide pin is replaced. FIG. 4B is a cross-sectional view after the guide pin has been attached.
[0014]
The vicinity of the center of the electrode rod 2 is attached to the round arm 1 of the spot welder. A tapered surface is formed on the outer periphery of the electrode tip 3 and the inner diameter of the fitting groove 11 at the upper part of the electrode rod 2, and when the electrode tip 3 is inserted into the fitting groove 11, the tapers are engaged and clamp force is increased. And the electrode tip 3 is fixed. A through hole 4 having a size that allows the guide pin 5 to move up and down is formed on the axial center line (YY) of the electrode tip.
[0015]
Between the through hole 12 and the fitting groove 11, a joint 13 for connecting the rear end of the guide pin 5 is inserted, and a storage groove 17 having a size capable of moving up and down is formed. On the lower part of the electrode rod 2, an elevating means 7 is applied to the bracket 9 so as to apply pressure to push up the guide pin 5 so that the tip of the guide pin 5 protrudes from the electrode surface of the electrode tip 3 only by a specified dimension (h). The bracket 9 is fixed to the electrode rod 2 with a bolt 19 via a block 20.
[0016]
An air cylinder is used for the lifting means 7. The tip of the piston rod 8 of this air cylinder and the lower end of the guide rod 6 are connected via a joint 14 and a joint 15.
[0017]
A stopper piece 10 having a handle 16 is inserted between the joint and the mounting position of the bracket 9.
[0018]
The stopper piece 10 has grooves formed on both sides of the main body from the front to the middle. The stopper piece 10 is fixed to the positioning groove V by pressing plungers 18 attached to both sides of the bracket 9. The plunger 18 has a pressing force adjusted so that the stopper piece can be easily inserted and removed.
[0019]
Then, when the cylinder 7 pushes up the guide pin 5, the joint 14 abuts against the stopper piece 10 to restrict the rising position of the guide pin 5. Thereby, the length (h) of the tip of the guide pin is positioned from the electrode surface of the electrode tip 3.
[0020]
Reference numeral 21 denotes a cooling holder for cooling the electrode tip 3. The sealing member S is in contact with the outer periphery of the electrode rod 2 to form a cooling water groove U.
Next, a procedure for exchanging the guide pin 5 of the electrode device having the above configuration will be described.
[0021]
First, the stopper piece 10 is pulled out with the handle 16 of the stopper piece 10. When the stopper piece 10 is pulled out, the vertical movement of the guide rod 6 becomes free as much as the stopper is pulled out. By removing the electrode tip 3 from the electrode rod 2 in this state, the guide pin 5 can be pulled out from the joint 13 in the arrow direction (→).
[0022]
Then, a new guide pin is replaced with the joint 13 from the arrow direction (←) and inserted into the electrode rod 2. Next, after the electrode tip 3 is inserted from above the guide pin 5 and pushed into the fitting groove 11, the stopper piece is inserted into the original position to complete the exchange.
[0023]
【The invention's effect】
As described above, according to the present invention, since the removable stopper means is provided between the lower end of the electrode rod and the joint, the guide pin can be easily removed by pulling out the stopper means when replacing the guide pin. As a result, the guide pin can be replaced in a short time.
[0024]
In addition, according to the present invention, the number of parts of the lower electrode can be reduced, the electrode structure can be simplified, and the production cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the overall structure of a lower electrode device of the present invention.
FIG. 2 is an AA arrow view of FIG.
FIG. 3 is a view taken along arrow BB in FIG. 1;
FIG. 4A is a cross-sectional view showing a removed state when the guide pin is replaced.
(B) It is sectional drawing after the completion of attachment of a guide pin.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 .... Arm of a spot welder 2 .... Electrode rod 3 .... Electrode tip 4 .... Through hole 5 .... Guide pin 6 .... Guide rod 7 .... Lifting means (cylinder)
8 ... Piston rod 9 ... Bracket 10 ... Stopper means (piece)
11 .... Fitting groove 12 ... Through hole 13 ... Joint 14 ... Joint 15 ... Joint 16 ... Handle 17 ... Storage groove 18 ...・ Plunger

Claims (1)

A lower electrode in which an electrode tip (3) is inserted into an electrode rod (2) supported by an arm (1) of a spot welder, and a tip of a guide pin (5) protrudes from a through hole (4) of the electrode tip to a specified dimension An upper end of a guide rod (6) inserted concentrically with the axial center line (YY) of the electrode rod and the guide pin are connected via a joint (13), and the guide rod And a rod (8) of an elevating means (7) operating the same are connected via a joint (14), and the cylinder and the electrode rod are supported via a bracket (9). argument between the joint (14), stop means (10) is seated detachably, said stopper means in the mechanism for attaching and detaching said guide pin from the joint from the detachable position The vertical movement of the guide rod is made free, the insertion / removal direction for attaching / detaching the electrode tip is the same as the axial center line of the electrode rod, and the guide pin (5) of the guide pin (5) The lower electrode device characterized in that the insertion / removal direction is a direction perpendicular to the axial center line.

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