JPH0221192Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an electrode for a spot welding gun of a spot welding machine.

(Prior art) Conventional electrodes for spot welding guns were developed in U.S. Pat.
As described in Publication No. 143846, the electrode tip is supported via a ball joint at the tip of the joint rod fitted into the electrode holder of one electrode, so that the electrode tip can swing freely, and the axis of the electrode can be adjusted. It is known that spot welding can be carried out by tilting the metal plate instead of perpendicularly to the metal plate.

However, as shown in FIG.
0, no means for regulating the posture of the electrode tip 106 is provided, so the electrode tip 106 maintains its tilted posture even after welding by tilting the axis of the electrode 100 without making it perpendicular to the metal plate 124. When performing welding with the axis of the electrode perpendicular to the metal plate 124, the electrode tip 106 in an inclined position is positioned perpendicularly to the metal plate 124.
The electrode tip 106 not only hits unevenly and leaves impressions on its surface, which deteriorates the quality of the product's appearance, but also damages the electrode tip 106.
The wear and tear was also severe.

Furthermore, since the electrode tip 106 is attached to the joint rod 107 via a ball joint, it is not possible to replace only the electrode tip 106, which is a consumable item, and the entire joint rod 107 must be replaced, which is extremely uneconomical. .

(Purpose of the invention) In order to eliminate the above-mentioned drawbacks, the present invention has developed a spot welding method in which the electrode tip always returns to its normal position located on the axis of the electrode, and only the electrode tip can be replaced. The purpose is to provide electrodes for cancer.

(Structure of the invention) The feature of the structure is that the proximal end of the flanged rod is loosely inserted into the cylindrical socket externally screwed onto the electrode base member of at least one of the electrodes, and the flanged rod is inserted into the cylindrical socket. The flanged rod is made swingable by bringing the convex spherical seat at the base into contact with the receiving surface of the electrode base member, and a coil spring interposed between the flanges of the flanged rod and the socket allows the flanged rod to be attached to the electrode base member. In addition to biasing and supporting the rod, an electrode tip having a flat surface is tapered fitted to the tip of the flanged rod.

(Effect of the invention) Since the invention is constructed as described above, when a metal plate is not sandwiched between both electrodes, the flanged rod is positioned coaxially with the axis of the electrode due to the elastic force of the coil spring. Automatically returns to normal posture.

Therefore, in the process of repeating normal spot welding many times, the flat surface of the electrode tip comes into contact with the metal plate in parallel or at a small angle of contact, and the uneven contact of the tilted electrode tip can damage the surface of the metal plate. This not only improves the quality of the product, but also extends the life of the electrode chip.

Further, since the cylindrical socket is externally fitted and screwed onto the electrode base member, the spring force can be adjusted by threading the cylindrical socket onto the electrode base member and rotating the two to change their relative positions.

In addition, since the electrode tip, which is a consumable item, is tapered and fitted into the flanged rod, the electrode tip alone can be easily attached and detached, and the structure of the electrode tip is simplified, resulting in lower manufacturing costs.
Extremely economical.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

The spot welding gun 1 of the spot welding machine has a first
As shown in the figure and FIG. 2, a pressure cylinder 3 is provided at one end of a C-shaped frame 2, and a movable side electrode 4 provided on the piston rod of the pressure cylinder 3 and a fixed side electrode 5 at the other end of the frame 2. are arranged coaxially and facing each other. When performing spot welding, a plurality of stacked metal plates 24 are inserted between both electrode tips 6 and 7, the fixed side electrode tip 7 is brought into contact with the metal plate 24, and the movable side electrode 4 is pressed with the pressure cylinder 3. By advancing the metal plate 24 between both electrode chips 6 and 7.
The material is clamped and pressurized, then energized and spot welded.

The fixed electrode 5 includes an electrode holder 8 fixed to the frame 2 and an electrode chip 7 fitted to the electrode holder 8.
It consists of.

On the other hand, the movable electrode 4 is configured as follows. An electrode base member 10 is tapered fitted into an electrode holder 9 which also serves as a piston rod of the pressurizing cylinder 3, and a cylindrical socket 11 is fitted to the electrode base member 10.
A hollow accommodating part 12 is formed in the socket 11 protruding from the electrode base member 10, and the proximal end of the flanged rod 13 is loosely inserted into the accommodating part 12. , the tip of the flanged rod 13 is made to protrude outward from the tip opening 14 of the accommodating portion.

A concave spherical receiving surface 15 is formed on the distal end surface of the electrode base member 10 facing the housing portion 12, and a convex spherical seat 16 provided on the proximal end surface of the flanged rod 13 is formed on this receiving surface 15.
By bringing these into contact with each other, the flanged rod 13 can swing within a predetermined angular range.

Furthermore, a compression coil spring 19 is interposed between the collar 17 forming the outer circumferential portion of the convex spherical seat 16 of the flanged rod 13 and the annular receiving portion 18 of the socket 11, and its elastic force causes the flanged rod 13 to move toward the electrode. It is biased and supported by the base member 10.

Here, the electrode tip 6 is removably tapered fitted onto the distal end side of the flanged rod 13, and the distal end surface of the electrode tip is formed into a circular flat surface 20. An annular groove is provided near the center of the electrode tip 6 in the axial direction as a gripping part 21 for gripping it with a tool when replacing the electrode chip 6. When the electrode tip 6 is worn out near the gripping part 21, Exchange.

Note that the diameter of the portion where the flanged rod 13 is inserted through the tip opening 14 is made somewhat smaller, so that the swing gap 22 is made larger.

Here, instead of the concave spherical bearing surface 15, a flat bearing surface 15 is formed as shown in FIG. 4 to compensate for the lack of welding current carrying area and to prevent wear of the convex spherical seat 16. For this purpose, conductive grease 23 may be filled between the receiving surface 15 and the convex spherical seat 16 and the space in the vicinity thereof.

In the above configuration, the flanged rod 13 can swing in all directions within a predetermined angle range through the spherical contact between the convex spherical seat 16 and the receiving surface 15 of the flanged rod 13, as shown in FIG. Place the axis of the electrode on the metal plate 2.
4 can be welded at an angle without being perpendicular to the rod 4. However, when the pressure from the pressure cylinder 3 is released after welding, the elastic force of the coil spring 19 evenly applied to the outer circumference of the flange 17 causes the flange rod to be welded. 13
immediately returns to its normal position coaxial with the axis of the electrode 4.

Since the spherical seat of the flanged rod 13 is a convex spherical seat 16, its swing center 25 is located near the approximate center of the flanged rod 13, so that the tilted electrode tip 6
The amount of shift from the original position becomes small, and the swing distance 22 of the tip opening 14 also becomes small.

Also, the current during welding is between the receiving surface 15 and the convex spherical seat 16.
The flow flows smoothly through the wide contact surface between them, and the pressurizing force during pressurization is shared by the wide contact surface, which reduces surface pressure.

The tapered fit between the electrode tip 6 and the flanged rod 13 can be easily removed by pressing the electrode tip 6 toward the distal end while the flanged rod 13 is clamped with a tool or the like.

In the above embodiment, the spot welding gun 1 having a C-shaped frame has been described, but the present invention is of course not limited to the above, and can be applied to X-shaped or other types of spot welding guns.

The present invention can be applied not only to movable electrodes but also to fixed electrodes, and can be applied to both at the same time.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention, in which FIG. 1 is a side view of a spot welding gun, FIGS. 2 and 3 are partial longitudinal sectional side views in each welding state, and FIG. 4 is a side view of a spot welding gun. 2 is a partial view of a modified example, and FIG. 5 is a partial longitudinal sectional side view of the electrode of the prior art. 1... Spot welding gun, 4, 5... Electrode, 6
... Electrode chip, 10 ... Electrode base member, 11 ...
Socket, 13... Rod with flange, 15... Receiving surface, 16... Convex spherical seat, 17... Flange, 19... Coil spring, 20... Flat surface, 24...
metal plate.

Claims (1)

[Scope of utility model registration request] In a spot welding gun electrode in which a plurality of stacked metal plates are sandwiched and pressed between a pair of opposing electrodes to apply electricity, a cylindrical socket externally fitted and screwed onto the electrode base member of at least one of the electrodes is used. The proximal end of the flanged rod is loosely inserted, and the convex spherical seat at the proximal end of the flanged rod is brought into contact with the receiving surface of the electrode base member.
The flanged rod is biased and supported on the electrode base member by a coil spring interposed between the collar of the flanged rod and the socket, and an electrode tip having a flat surface is tapered fitted to the tip of the flanged rod. Electrode for spot welding gun.