KR19980033709A - Trace removal device for spot welding - Google Patents

Abstract

The present invention relates to a trace removal apparatus for spot welding to remove traces generated in the welded portion during spot welding, which is a kind of welding with pressure method.

To this end, the present invention is a jig composed of a plate-shaped reference plate, a material support plate fastened through a plurality of bolts to be height-adjustable on the upper side of the reference plate, and a cushion material installed between the reference plate and the material support plate. As a trace removing device of the type, the material to be welded is placed on the top of the material support plate while the movable electrode and the fixed electrode are positioned on the upper and lower sides of the material support plate, and the movable electrode is moved to the fixed electrode. By the elastic restoring force of the cushioning material when the elastic material is elastically bent or deformed to the bottom of the support plate with holes, or the cushioning material is compressed while the deformation of the material is slight, and the heated material becomes flexible along with the welding process. The material will undergo elastic bending deformation.

When the welding is completed, the elastically deformed material is returned to its original shape and hardly any depression marks occur in the direction of the fixed electrode during elastic deformation.

Description

Trace removal device for spot welding

The present invention relates to an apparatus for removing traces of a weld part generated by a pressing force of a movable electrode during spot welding, which is a kind of welding with pressure method.

More particularly, the present invention relates to a trace removing device during spot welding, which minimizes or suppresses depression traces of convexly deformed portions by performing welding on a material that is elastically deformed in a gently curved shape by the pressing force of the movable electrode. .

Welding method, commonly called welding or pressure welding, is a general method of welding by applying mechanical pressure to a material, which includes electric resistance welding such as spot welding, seam welding, and projection welding. And welding involving powerful pressurization such as flash welding and friction welding, ultrasonic welding as a solid state welding using ultrasonic waves, explosion welding using explosive force of gunpowder, and single welding hitting or pressing heated metal. There are many ways.

Among them, spot welding overlaps two metal plates of the material 100, as shown in FIG. 1, between the upper and lower movable electrodes 50 and fixed electrodes 60 electrically connected to the transformer 110, and fixes the movable electrodes. This is a method of moving a large current while applying pressure to a material by moving it toward an electrode so that the contact points of both materials are welded together.

In addition, a spot welding machine used for spot welding is a welding machine that stores electrical energy necessary for spot welding electronically or electrostatically and then rapidly discharges and welds them. There are a type and a direct-type pressurization type, and there are a single phase AC type, a three phase type, and a heat storage type as a classification by a power supply method or a waveform of a current.

However, such spot welding has a disadvantage in that concave depressions are generated in the part where the welding electrode of the material touches after welding in addition to the advantage of locally bonding the material to achieve the desired purpose.

In order to remove such recessed traces, post-processing such as grinding (Granding) has been mainly performed around the recessed area after welding, which has only resulted in another trace for removing traces.

In other words, grinding operation alone cannot completely eliminate the depression, leaving new grinding marks on the surface of the material, which impairs quality defects and aesthetics, and adds unnecessary grinding processes to increase the cost and reduce productivity. there was.

Further, in addition to the above grinding operation, another prior art is the spot welding apparatus of Korean Patent Publication No. 95-23477.

This spot welding device is designed to avoid depression due to spot welding while maintaining the same plane by applying an auxiliary plane to the welded part and the surrounding part of the workpiece where spot marks are generated. For this purpose, a lifting mechanism for supporting (upper) electrodes and a lifting mechanism for supporting (lower) rear (electrode) support bars for controlling the moving speed and the supporting pressure of the welding electrode is constructed.

However, since the device requires an additional electric control device for pressure and speed regulation, it is difficult to expect a practical effect, and the device has an uneconomical disadvantage due to its large size.

In addition, the resistance welding pole for welding trace prevention of Korean Utility Model Publication No. 86-013092 forms a protrusion on the electrode, and a ring of an insulator for dissipating a current path on the circumferential surface of the protrusion and a force ring for dispersing the pressing force. To prevent welding marks.

However, this is only a partial improvement of the electrode, there is a disadvantage that can not flexibly cope with the material change of the material.

Opening door welding structure of subway trains disclosed in Korean Utility Model Publication No. 94-005235 is to remove traces generated during welding of electric resistance spots between the frame and the steel plate that constitute the opening doors of subway trains. By forming the projections in advance, so that the projections are melted during welding so that the appearance of recessed traces do not remain.

In addition, the method of spotless spot welding of Korean Patent Publication No. 97-069221 and a device for implementing the same relate to a welding method for joining a bonnet, a trunk lid, etc. in automobile manufacturing. Laser welding is performed while argon (Ar) gas is blown to prevent traces.

However, this is not an electric resistance welding method, and there is a problem in that the device cannot be simply mounted and used in a conventional spot welding device due to the complicated and oversized relationship.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and a technical problem thereof is to provide a trace removing device capable of minimizing or suppressing traces of recessed welds without performing post-processing such as grinding during spot welding.

1 is a schematic view of a spot welder

2 is a perspective view showing an embodiment of the present invention

3 is a front cross-sectional view showing an embodiment of the present invention.

Figure 4 is a front sectional view showing an operating state according to an embodiment of the present invention

Figure 5 is a front sectional view showing an operating state of another embodiment of the present invention

※ Explanation of code for main part of drawing

10: reference plate 11: hole

20: bolt 21: screw

22: head 30: material support plate

31 hole 32 bend

40: cushioning material 41: spring

50: movable electrode 60: fixed electrode

100: material

The present invention for achieving the above object is a jig (Jig) -type device that can be easily attached to a conventional electric resistance spot welder, and a flat plate type reference plate having a hole for mounting or fixing electrodes, A material support plate inserted into the reference plate so as to be rotatable and having a plurality of bolts all of which are located in the same direction, and which are fastened to the screw and installed to be adjustable in height, and having a hole into which a fixed or movable electrode is inserted; It is composed of cushioning material that is compressed between the base plate and the base plate and compressed or expanded by an external force applied to the base plate.

At the time of installation, in consideration of the elastic force (thickness, material, elastic modulus, etc.) of the material to be welded, the fixed and movable electrodes are mounted and fixed to existing spot welders so as to be located at the upper side and the lower side, or the opposite direction, respectively.

At the time of welding, the material is piled up on the top of the material support plate, and spot welding of the material is performed while moving the movable electrode toward the fixed electrode.

In this case, in the case of a material which is easily elastically deformed, the welding part located at the upper end of the hole of the material support plate is elastically deformed to form a gentle curve under the pressure of the movable electrode, and is bent downward to contact the fixed electrode to be welded. At the same time as the movable electrode returns to its original position, the welded portion that has been bent by its own elastic force returns to its original position.

In addition, when the elastic deformation is not easy at room temperature, the cushion material is compressed by the pressure of the movable electrode applied to the material, and the bolt, the material support plate, and the material are simultaneously lowered, and the welding is started by contacting the fixed electrode. When the material is sufficiently heated, the material becomes flexible and at the same time, bending deformation occurs around the welding point in a gentle curved form by the elastic restoring force of the compressed cushioning material.

As the welding progress time continues, the welding heat increases, and the size of the material bending deformation increases with the restoring size of the cushion.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a perspective view showing an embodiment of the present invention, Figure 3 is a front sectional view showing an embodiment of the present invention.

As shown, the present invention includes a flat plate type reference plate 10 supporting the entire apparatus and having a hole 11 on which movable or fixed electrodes 50 and 60 are mounted;

A plurality of height adjusting bolts 20 rotatably inserted in the reference plate and the screw portions 21 all positioned in the same direction;

A material support plate 30 fastened to the screw part and installed to adjust the height, and having a hole 31 into which a movable or fixed electrode is inserted;

A cushion member 40 which is installed between the reference plate and the material support plate to compress or expand in the longitudinal direction by an external pressure applied to the material support plate; It consists of.

The reference plate 10 is a stack of two metal plates in the form of a plate, and serves as a base plate for supporting the entire device, and a hole 11 into which the movable or fixed electrodes 50 and 60 are inserted is integrally formed in the center. This hole has a size sufficient to accommodate a movable and fixed electrode and a holder for fixing these electrodes.

The plurality of height-adjusting bolts 20 are all bolts of the same size so as to rotate and move up and down from the bottom of the reference plate, and the screw portion 21 and the head portion 22 are upper and lower portions of the reference plate 10, respectively. Located in

The material support plate 30 is screwed to the threaded portion of the bolt to form a horizontal with the reference plate 10, the height is adjustable by the rotation of the bolt.

In the center of the material support plate, a hole 31 into which the movable or fixed electrodes 50 and 60 are inserted is integrally formed, and the hole is large enough to accommodate the movable and fixed electrodes and a holder for fixing the electrodes. The upper end of the hole 31 is formed integrally with a rounded curved portion 32 extending outward.

The material support plate is electrically insulated from the material 100 which is partially or entirely insulated and placed on top thereof.

The cushion material 40 is inserted into the bolt 20 between the reference plate and the material support plate to elastically support the material support plate, and the material support plate is lowered while being compressed or expanded in the longitudinal direction by the external pressure applied to the material support plate. .

Although the cushion member 40 is shown as a spring 41 in the drawing, in addition to this, rubber, urethane, or the like may be used.

Referring to the operation and operation of the present invention configured as described above are as follows.

First, the apparatus of the present invention is mounted and fixed to a spot welder before the welding operation is performed.

That is, the reference plate 10 is fixed to the fixed shaft or the moving shaft of the electrodes 50 and 60 provided in the spot welding machine, so that the movable electrode 50 is positioned above the material support plate 30, and the fixed electrode 60 is What is necessary is just to be fixed to the reference plate 10 via a holder etc.

In this case, the positions of the movable and fixed electrodes may be reversed depending on the shape, thickness, material, elastic modulus, etc. of the material 100, but in the drawings, the movable and fixed electrodes are installed on the upper and lower sides of the material support plate. have.

When the device is fixed, the material 100 to be welded is placed on the top of the material support plate 30 so that the welding starts.

Once the welding process is started, the operating condition depends on the type of material.

That is, when the elastic deformation of the material is easy, as shown in FIG. 4, when the movable electrode is in contact with the material 100, a pressing force is applied to the welding part positioned on the curved part 32 and the hole 31 of the material support plate 30. Is bent downward while causing elastic deformation in the form of a gentle curve, and then discharge starts from the moment when the material comes into contact with the fixed electrode to start welding.

When the welding is finished in this elastic bending deformation state and the movable electrode returns to its original position, the material is restored to its original shape from the elastic deformation, and the depression of the welding point at the convex portion cannot be found.

This is because welding was performed under elastic convex deformation.

In addition, when the elastic deformation is not easy at room temperature, since the pressure of the movable electrode applied to the material acts on the cushioning material 40 through the material support plate 30 as shown in FIG. The material support plate and the material are simultaneously lowered and discharge is performed from the moment when the lower end of the material contacts the fixed electrode, thereby welding is performed.

At this time, during welding, the welded portion and its surroundings are heated and softened, so that a gentle curved elastic deformation occurs around the welded portion due to the elastic restoring force of the cushioning material 40 that has been compressed.

As the welding heat increases, the size of the deformation increases, but the welding ends when the maximum vertical moving distance of the bending deformation is less than or equal to H (see FIGS. 3 and 4).

After the welding is completed, when the movable electrode rises, the pressing force is released and at the same time the bolt, the material support plate and the material rise simultaneously to return to the original position, and the bent deformation welding part returns to the original shape. Hard to find traces

This is because the welding is performed in the elastic convex deformation state, as in the case where the elastic deformation is easy.

As described above, the present invention can minimize or suppress the depressed traces generated on the surface of the material during welding by using the hole or the cushion material provided with the curved portion according to the type and elastic force of the material.

In addition, in addition to the above description, the distance of H, which is the distance between the material and the fixed electrode 60, may be adjusted through the rotation of the bolt 20, and thus may correspond to a wider variety of materials.

As described above, the present invention constitutes a jig-shaped trace removal device that can be easily attached to a conventional electric resistance spot welder, and puts the material to be welded on the top of the material support plate, When the movable electrode is moved toward the fixed electrode while the movable electrode and the fixed electrode are positioned above and below, the welding material is deformed according to the Young's Modulus.

As the movable electrode moves downward into the hole of the material support plate, the material with small elastic modulus generates a gentle curved elastic deformation around the contact point of the two electrodes, and the elastic deformation is terminated with the contact between the two electrodes. Proceed.

When the welding is completed and the movable electrode returns to its original position, the material is restored to its original shape from the elastic deformation, and no depression marks occur.

This is the result of welding performed in the elastic convex deformation state.

As the elastic modulus increases, the material decreases its elastic deformation when the movable electrode moves downward. Instead, the support plate moves downward and the cushioning material is compressed together.

If the elastic modulus is large enough, the material compresses only the cushion material up to H with little elastic deformation while the movable electrode moves the distance H.

When the welding heat makes the material sufficiently flexible after the contact and energization of the two electrodes are started, elastic bending deformation occurs around the welding point due to the elastic restoring force of the cushion material.

The deformation can be increased up to the maximum deformation range (H) until the energization ends.

When the welding is completed and the movable electrode returns to its original position, the material is restored to its original state from the elastic deformation, and no depression marks occur.

The decisive reason for not causing depression in the apparatus of the present invention is that the jig structure allows welding to be performed in an elastic deformation state in which the shape of the convex portion is maintained at the welding point regardless of the size of the elastic modulus.

In addition, the present invention can adjust the distance between the material and the fixed electrode through the bolt can respond quickly to various types of material, the device itself compared to the method of moving the movable and fixed electrode through the existing electrical control device It's simple and it's very economical.

Claims (6)

A reference plate 10 supporting the entire apparatus and having holes 11 for mounting movable or fixed electrodes 50 and 60; A plurality of height adjusting bolts 20 rotatably inserted in the reference plate and the screw portions 21 all positioned in the same direction; A material support plate 30 fastened to the screw part and installed to adjust the height, and having a hole 31 into which a movable or fixed electrode is inserted; A cushion member 40 which is installed between the reference plate and the material support plate to compress or expand in the longitudinal direction by an external pressure applied to the material support plate; Trace removal device for spot welding, characterized in that consisting of. The apparatus for removing spots during spot welding according to claim 1, wherein the material support plate (30) is insulated part or all of the material supporting plate (30) for electrical blocking from the material (100). According to claim 1, Spot removal apparatus for spot welding, characterized in that the rounded curved portion 32 is integrally formed on the upper end of the hole (31) of the material support plate (30). The apparatus for removing spots during spot welding according to claim 1, wherein the cushion material is a spring. 2. The apparatus for removing spots during spot welding according to claim 1, wherein the cushion material is rubber. The apparatus for removing spots during spot welding according to claim 1, wherein the cushion material is urethane.