JPH0839268A - Working jig for reuse of half split electrode - Google Patents

Abstract

PURPOSE:To provide a working jig for reuse of a half split electrode of easy attaching/detaching and capable of holding an electrode while precisely positioning. CONSTITUTION:The electrode 3 consisting of a pair of half members 3a is fitted in an electrode holder 14 and is screwed from above by a cap 18, an outward flange 10 at the upper end of electrode 3 is tightened between the bottom part of expanding step hole 16 and the inward flange 19 of cap 18 so as to be made to horizontal, under this state, by inserting a drill 21 in the center of both half members 3a and cutting, a work contacting face 12 for reuse precisely is cut.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jig for reusable processing of a half-divided electrode used for welding a hard metal tip to the tip of an automobile engine valve or the like. .

[0002]

2. Description of the Related Art At the shaft end of an engine valve of an automobile or the like,
Hard metal tips are sometimes welded to improve wear resistance. As shown in FIG. 4, the welding of this tip is carried out on the lower electrode (4) provided on the base (6) which can move up and down.
A disk-shaped hard metal chip (2) is placed and the shaft end of the engine valve (1) perpendicular to the upper surface is abutted, and the base (6) is raised to support the upper support base. Press down on (7) and hold.

In this state, from the left and right of the shaft portion of the engine valve (1), the upper electrode (3) consisting of a pair of half members (3a) (3b) attached to the opposing surfaces of the support members (5) (5). ) Abut.
The inner surface of the pair of half members (3a), (3b) has an engine valve
A recess having a semicircular cross section formed of an arc having the same diameter as the shaft portion of (1) is formed so as to be in close contact with the shaft portion of the engine valve (1). When electricity is applied between the upper and lower electrodes (3) and (4), the hard metal tip (2) is welded to the shaft end of the engine valve (1).

[0004]

When the welding of the above-mentioned tip is repeated, the contact surface of the electrode, especially the upper electrode, with the work is deteriorated by electrolytic corrosion and roughened, resulting in poor current-carrying characteristics. It becomes impossible. Conventionally, the disabled upper electrode has been discarded. However, in order to reduce the manufacturing cost, only the contact surface with the work is defective,
It is not reasonable to discard the top electrode.

An object of the present invention is to use a jig used for processing such a used half-divided electrode for tip welding as a welding electrode for a work having a larger diameter. It is an object of the present invention to provide a processing jig in which the electrodes can be easily attached and detached and the electrodes can be accurately positioned and held.

[0006]

According to the present invention, the above object is to provide a semi-cylindrical outward flange at the upper end of a semi-cylindrical portion and a semi-circular hole on the inner surface for contacting a workpiece.
A machining jig for reusing a half-divided electrode composed of a pair of half members, wherein the upper end of a holding hole into which the half cylinders of the both half members can be fitted concentrically is provided. An electrode holder having a diameter-expanded step hole shallower than the thickness and having an external thread on the upper outer peripheral surface and an internal thread that can be screwed into the external thread of the electrode holder are provided on the inner surface, and the outward flange of the electrode is pressed. This is solved by a processing jig for reuse of a half-divided electrode, which is provided with a cap having an inward flange and a through hole through which a diameter-expanding drill passes.

[0007]

When the electrode composed of a pair of half members is fitted into the holding hole in the electrode holder and the cap is tightened from above, the outward flange of the electrode is located between the bottom of the enlarged diameter step hole and the inward flange of the cap. Then, by inserting a drill into the center of both half members and cutting in the horizontal state, a new work contact surface is accurately cut on both half members.

[0008]

1 to 3 are views showing a working jig which is an embodiment of the present invention together with a half-divided electrode (3) to be reused. This processing jig comprises an electrode holder (14) and a cap (18). The electrode holder (14)
A recess having a shape corresponding to the outer shape of (3) is provided. This recess is located at the upper end of the semi-cylindrical part (11) with an approximately semicircular outward flange (1
(0) corresponding to the outward flange (10) of the electrode (3) consisting of a pair of half-members (3a) (3b), and having a diameter-expanding step hole having a depth shallower than the thickness of the outward flange (10). 16) and a holding hole (17) into which both the semi-cylindrical parts (11) can be fitted concentrically. A male screw (15) is cut on the outer peripheral surface of the upper portion of the electrode holder (14).

A pair of spacer pins (13), which are smaller than the depth of the expanded diameter hole (16), are provided at the bottom of the expanded diameter hole (16).
It projects upwards at 180 ° intervals.

Each half member (3a) (3b) of the electrode (3) is not normally a perfect half cylinder, but is true when both half members (3a) (3b) are faced apart by about 3 mm. It is shaped like a circle. The pins (13) are for ensuring an interval of about 3 mm when holding when facing each other. Both half members (3a) (3b)
May be formed so as to form a perfect circle when they are brought into contact with each other, and in such a case, the pin (13) is unnecessary.

The cap (18) is a nut-shaped one having an internal thread (22) on its inner peripheral surface, which is screwed to the external thread (15) of the above-mentioned electrode holder (14), and has an electrode holder at the top thereof. An inward flange (19) for pressing the flange (10) of the electrode (3) housed in (14) is formed. A through hole (20) is provided at the center of the inward flange (19). This through hole (20)
Is larger than the diameter of the drill (21) for diameter expansion processing described later.

When processing the used electrode (3),
First, the half members (3a), (3b) of the electrode (3) are attached to the electrode holder (14).
It is inserted into the holding hole (17) of the above from above. At this time, each half member
(3a), (3b) facing outward flange (10), a pair of pins (1
Contact 3).

Then, cap the electrode holder (14) on top.
(18) and attach the female screw (22) of the cap (18) to the electrode holder (1
Tighten it by screwing it onto the male screw (15) of 4). Then, the inward flange (19) of the cap (18) becomes the outward flange of the electrode (3).
The electrode (3) is firmly and horizontally held by fastening the (10) to the bottom of the expanded diameter step hole (16) of the electrode holder (14). Thus, the work contact surface (1
2) is accurately centered.

The electrode (3) centered and fixed in this way
On the other hand, when the diameter is expanded by the drill (21) from above, a new expanded semicircular workpiece contact surface (12 ')
Is obtained. This amount of diameter expansion is usually about 3 to 3 mm, but it goes without saying that it varies depending on various diameters of the shaft portion of the engine valve. In this way, the small diameter electrode can be reused in sequence as the large diameter electrode.

[0015]

By using the processing jig of the present invention, the damaged work contact surface of the used electrode is scraped off,
A new, larger-diameter workpiece contact surface can be formed and used for tip welding of a larger-diameter engine valve or the like.

Further, after both half members of the electrode are fitted into the electrode holder from above, the outward flanges of both half members can be fitted to the bottom portion of the enlarged diameter step hole of the electrode holder and the cap only by tightening the cap from above. It is clamped horizontally with the inward flange, horizontal, and reliably positioned, so that when piercing with a drill, each half member does not tilt or move inadvertently.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an embodiment of the present invention.

FIG. 2 is likewise a vertical sectional front view showing a state at the time of processing for reuse.

FIG. 3 is a plan view of the same.

FIG. 4 is a schematic front view showing a state where an electrode to be processed using the jig of the present invention is used for welding a tip of an engine valve.

[Explanation of symbols]

 (1) Engine valve (2) Tip (3) Upper electrode (3a) (3b) Half member (4) Lower electrode (5) Support member (6) Base (7) Support base (10) Outer flange (11) Semi-cylindrical part (12) (12 ') Work contact surface (13) Pin (14) Electrode holder (15) Male screw (16) Expanding step hole (17) Holding hole (18) Cap (19) Inward flange (20) Through hole (21) Drill (22) Female thread

Claims (1)

[Claims] 1. A process for reusing a half-divided electrode comprising a pair of half-members having a semi-circular outward flange on the upper end of a semi-cylindrical portion and a semi-circular hole on the inner surface for contacting a workpiece. A jig for use in which a semi-cylindrical portion of both of the half members is concentrically fitted, has a diameter-expanding step hole shallower than the thickness of the outward flange at the upper end of the holding hole, and has an external thread on the upper outer peripheral surface. A cap having an electrode holder having a cut end, an internal thread having an internal thread that can be screwed into a male thread of the electrode holder, and an inward flange for pressing the outward flange of the electrode, and a through hole through which a diameter-expanding drill passes. And a processing jig for reusing a half-divided electrode.