JP7364897B2 - Stud welding method and jig for preventing spatter adhesion - Google Patents

Description

The present invention relates to a stud welding method for welding a workpiece and a stud. The present invention also relates to a jig for preventing spatter adhesion used in a stud welding method.

Stud welding is a process in which a stud (e.g. pin, bolt, screw) is pressed against the surface of an object to be welded (e.g. a steel plate), an arc is generated between the two, and then the stud is pressed against the object to be welded. This is a welding method. Depending on the type of power supplied, there are two types: capacitor type and electric arc type. The capacitor method is also called CD (Capacitor Discharge) stud welding. Figure 5 shows a schematic diagram of stud welding using the capacitor method. Anode or cathode wiring 35 of a stud welder 34 is connected to the stud welding gun 21 . The object to be welded 20 placed on the support stand 37 is connected to a ground wire 36 having the opposite polarity. A small protrusion (not shown) is provided at the tip of the stud 10.

The stud welding gun 21 is equipped with a stud mounting jig 7 for holding the stud at its tip, and the stud welding gun 21 holding the stud 10 presses the protrusion of the stud 10 against the workpiece to be welded. Then, when the stud welding gun 21 is turned on, the electricity stored in the capacitor of the stud welding machine 34 flows into the protrusion at the tip of the stud in an extremely short period of time, and between the workpiece 20 and the stud 10. An arc occurs. At the same time, it is possible to press the stud 10 against the object to be welded 20 and instantly weld them together.

FIG. 6 shows a state before welding in a conventional stud welding method. 6(A) shows a state before the stud 10 (stud bolt) is attached to the stud mounting jig 7, and FIG. 6(B) shows a state in which the stud 10 has entered the inside of the stud mounting jig 7. shows. Moreover, FIG. 7 shows the state during and after welding in the conventional stud welding method. FIG. 7(A) shows the form during welding, and FIG. 7(B) shows the form after welding.

As shown in FIG. 6A, the stud 10 is inserted toward the first opening 8 of the stud attachment jig 7. The stud 10 before welding is stored inside the stud mounting jig 7, while a part of the stud body 11 is exposed outside the stud mounting jig 7, as shown in FIG. 6(B). is held in

Next, when stud welding is performed, as shown in FIG . Further, the molten metal is scattered around as spatter 24. Therefore, as shown in FIG. 7B, scattered spatter 24 and fume 25 inevitably adhere to the surface of the stud 10 after welding. For example, when stud welding is performed using a stud bolt, if spatter or other debris adheres to the threaded portion of the stud bolt, the groove of the threaded portion will be filled, making it difficult to tighten with the nut portion of another member. In stud welding, there has been a problem in that the quality of the stud welded product is degraded due to adhesion of spatter and the like. Note that in this specification, spatter and materials scattered during welding such as fume may be collectively referred to as "spatter".

In particular, when the object to be welded is a surface-treated steel sheet such as a zinc-based plated steel sheet, stud welding is performed using a higher voltage range than for ordinary steel. During welding, the amount of melted base material of the galvanized steel sheet increases, so the amount of spatter scattered also increases. As a result, spatter tends to adhere to the stud, leading to defects in the stud product.

Conventionally, a method of applying a slag adhesion prevention liquid as disclosed in Patent Document 1 has been proposed as a method for solving problems caused by spatter scattering. The slag refers to the same thing as sputter in this specification. In the method of Patent Document 1, an applicator equipped with an annular liquid supply is used. The supplied liquid is brought into contact with the surface to be welded with the slag adhesion prevention liquid attached to the supplied liquid, thereby forming an annular liquid adhering portion on the surface to be welded. A stud is then welded to the center of the ring. Since the slag scattered during welding floats on the liquid-attached part, the scattered slag can be removed by wiping the liquid-attached part with a cloth or the like after welding.

As a method for preventing spatter adhesion to studs, a method using a stud welding gun as disclosed in Patent Document 2 has been proposed. The stud welding gun of Patent Document 2 is equipped with a chuck that grips the stud, and the chuck has a spout that spouts gas toward the welding location. The ejected gas flows through the gap between the chuck and the stud and blows off spatter scattered during welding, thereby preventing the spatter from adhering to the stud.

Japanese Patent Application Publication No. 2016-155139 Japanese Patent Application Publication No. 2004-276104

Although the method of applying a slag adhesion prevention liquid disclosed in Patent Document 1 can prevent spatter adhesion to the surface of the workpiece to which the stud is to be welded, it cannot prevent spatter adhesion to the surface of the stud. In the method of Patent Document 2, the stud welding gun needs to be provided with a gas ejection means, and the stud welding device has a complicated structure, which increases the work cost.

Therefore, an object of the present invention is to provide a simple stud welding method that suppresses spatter adhesion to studs.

The present inventors completed the present invention by focusing on attaching a spatter adhesion prevention jig having a specific structure to the tip side of a stud mounting jig of a stud welding gun. Specifically, the present invention includes the following embodiments.

(1) A stud welding method for welding a workpiece and a stud using a stud welding gun, wherein the stud welding gun includes a stud mounting jig for holding the stud, and the stud is connected to a stud body. the stud base has a shape where the outer diameter of the stud base is larger than the outer diameter of the stud body, and the stud mounting jig has a first opening at one end into which the stud body can enter. a cylindrical member having a second opening at the other end into which a stopper that contacts the end surface of the stud body can be inserted, and having an insertion opening into which the stud body can be inserted; A stud welding method in which the stud is attached to the first opening side of a stud attachment jig and welded.

(2) A jig for preventing spatter adhesion, which is attached to a stud mounting jig of a stud welding gun for welding a workpiece and a stud, and is composed of a bottomed cylindrical member having a bottom wall and a side wall. The stud includes a stud main body and a stud base, the outer diameter of the stud base is larger than the outer diameter of the stud main body, and the bottom wall has a shape that allows insertion of the stud main body. the bottom wall has an inner surface that is in close contact with the tip side of the stud mounting jig, the inner diameter of the insertion port of the bottom wall is smaller than the outer diameter of the stud base, and the side wall is , a jig for preventing spatter adhesion, the jig having an inner surface that is in close contact with the outside of the stud mounting jig.

(3) The jig for preventing spatter adhesion according to (2) above, wherein the bottomed cylindrical member is made of a rubber material or a felt material.

According to the present invention, it is possible to prevent spatter from adhering to the stud, so when attaching other members to the stud bolt after welding, it is possible to tighten the nut onto the threaded portion of the stud bolt. Moreover, since the stud adhesion prevention jig according to the present invention can be reused, it contributes to cost reduction. It can be easily installed depending on the shape and dimensions of the stud. Further, the tip of the stud attachment jig for the stud welding gun is covered with the stud adhesion prevention jig to suppress adhesion of spatter, which has the effect of extending the service life of the stud attachment jig.

1 is a diagram for explaining an embodiment of a stud welding method according to the present invention, in which (A) shows a state before a stud is attached to a stud attachment jig, and (B) shows a state in which a stud is attached to a stud attachment jig; FIG. Shows the form entered inside. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining an embodiment of a stud welding method according to the present invention, showing a form during welding. FIG. 2 is a perspective view showing a sputter adhesion prevention jig according to the present embodiment. FIG. 3 is a schematic diagram showing an example of a sputter adhesion prevention means for a welded object, in which (A) shows a plan view of the adhesion prevention sheet, and (B) shows a form applied to a stud. FIG. 2 is a schematic diagram for explaining a conventional stud welding method. FIG. 3 is a diagram for explaining the configuration before welding in a conventional stud welding method, in which (A) shows the configuration before the stud is attached to the stud attachment jig, and (B) shows the configuration before the stud is attached to the stud attachment jig. Shows the form entered inside. It is a figure for explaining the form at the time of welding and after welding in the conventional stud welding method, (A) shows the form at the time of welding, and (B) shows the form after welding.

Embodiments according to the present invention will be described below. The invention is not limited to the following description.

(Stud welding method)
The present invention relates to a stud welding method for welding a workpiece to a stud using a stud welding gun. 1 to 3 show an embodiment of a stud welding method according to the present invention.

The stud welding gun includes a stud mounting jig that holds the stud. An example of a stud mounting jig is shown in FIGS. 1A and 1B. FIG. 1(A) shows the state before the stud 10 (stud bolt) is attached to the stud mounting jig 7, and FIG. 1(B) shows the state in which the stud 10 has entered the inside of the stud mounting jig 7. It is.

(stud)
As shown in FIGS. 1A and 1B, the stud 10 includes a stud body 11 and a stud base 12, and the stud base 12 has a larger outer diameter than the stud body 11. ing. Further, a protrusion 13 may be provided at the tip of the stud base 12. Here, an example in which a stud bolt is used as the stud 10 is shown.

(Stud mounting jig)
As shown in FIG. 1A, the stud mounting jig 7 has a first opening 8 at one end into which the stud body 11 can enter, and a stopper 22 at the other end that contacts the end surface of the stud body 11. is a cylindrical member having a second opening 9 into which it can be inserted. After the stopper 22 is inserted into the second opening 9 and attached, the stud attachment jig 7 is attached to the tip of a stud welding gun (not shown).

(Jig for preventing spatter adhesion)
The stud welding method according to the present invention is characterized in that a spatter adhesion prevention jig is attached to a stud attachment jig and welding is performed. As shown in FIG. 1(A), the spatter adhesion prevention jig 1 is a member having an insertion opening 2 into which a stud body 11 can be inserted. As described above, since the stud attachment jig 7 is attached to the tip side of the stud welding gun, the spatter adhesion prevention jig 1 is attached to the first opening 8 side of the stud attachment jig 7. Thereafter, the stud body 11 is advanced toward the first opening 8 of the stud attachment jig 7.

As shown in FIG. 1B, the stud body 11 enters the inside of the stud mounting jig 7 and reaches a position where it contacts the stopper 22. As shown in FIG. On the other hand, since the outer diameter of the stud base 12 is larger than the outer diameter of the stud main body 11, the stud base 12 cannot pass through the insertion opening 2 of the spatter prevention jig 1, and the bottom wall 3 of the spatter prevention jig 1 cannot pass through the insertion opening 2 of the spatter prevention jig 1. held in contact with. Therefore, a part of the stud main body is in a state of coming out from the first opening 8. In this way, the stud 10 is held by the stud attachment jig 7 and the spatter adhesion prevention jig 1. The outer diameter of the stud body 11 is approximately the same as the inner diameter of the first opening 8 and the second opening 9 of the stud attachment jig 7 so that the stud body 11 can enter and be held inside the stud attachment jig 7. It is. Further, the inner diameter of the first opening 8 is preferably smaller than the outer diameter of the stud base 12 so that the stud base 12 does not pass through the first opening 8 of the stud mounting jig 7.

A portion of the stud body 11 is housed in the stud mounting jig 7. The other portion of the stud main body 11 protruding from the first opening 8 of the stud mounting jig 7 is sealed off by the sputter adhesion prevention jig 1 and the stud base 12. In this way, the stud body 11 is placed in a state isolated from the welding location of the workpiece.

FIG. 2 schematically shows the configuration during stud welding. This is a diagram showing an example in which a plated steel plate 26 is used as an object to be welded, and a stud 10 is welded to the surface of a plated layer 27. As shown in FIG. 2, when the protrusion 13 at the tip of the stud 10 is brought into contact with the plated steel plate 26 and a voltage is applied, an arc 23 is generated between the stud base 12 and the protrusion 13 and the plated steel plate 26, and an arc current is generated. The stud 10 and the plated steel plate 26 are welded together by heating. During welding, spatter 24 and fume 25 are generated and scattered around the welding location. However, in the stud welding method according to the present invention, since the stud body 11 is isolated from the welding location, even if spatter 24 and fume 25 are generated in and around the welding location, the spatter etc. will not reach the surface of the stud body 11. Can prevent adhesion.

The spatter adhesion prevention jig according to the present invention is mounted on a stud mounting jig of a stud welding gun that welds a workpiece and a stud. As shown in FIGS. 1A and 1B, the stud 10 includes a stud body 11 and a stud base 12, and has a shape in which the outer diameter of the stud base 12 is larger than the outer diameter of the stud body 11. things are applied.

The structure of the sputter adhesion prevention jig according to the present invention is shown in FIG. As shown in FIG. 3, the sputter adhesion prevention jig 1 is composed of a bottomed cylindrical member having a bottom wall 3 and a side wall 4. As shown in FIG. The bottom wall 3 has an insertion opening 2 into which the stud body 11 can be inserted, and with this structure, the stud body 11 can be inserted into the stud mounting jig 7 through the insertion opening 2 of the spatter adhesion prevention jig 1. can be done. For example, the inner diameter of the insertion opening 2 of the bottom wall 3 is preferably larger than the outer diameter of the stud body 11 in order to make it easier for the stud body 11 to enter. The size may be 1.1 times or less.

The dimensions of the sputter adhesion prevention jig according to the present invention can be appropriately set depending on the size of the stud. For example, the thickness of the bottom wall and side wall of the sputter adhesion prevention jig can be 0.5 to 2.5 mm. The outer diameter of the bottom wall can be 12.0 to 15.0 mm, and the height of the side walls can be 10 to 15 mm.

As shown in FIG. 3, a slit 14 may be provided in the side wall 4 of the sputter adhesion prevention jig 1 to facilitate attachment to the stud attachment jig 7. In that case, in order to prevent the side wall 4 from tearing due to the widening of the slit 14, it is preferable to give one end of the slit 14 a roundness 16 with a curvature R. Furthermore, a fixing means that tightens around the side wall 4 with a band 15 or the like may be used.

Furthermore, the bottom wall 3 has an inner surface 5 that comes into close contact with the tip side of the stud attachment jig 7. The "tip side of the stud mounting jig" refers to the side facing the object to be welded. The inner diameter of the insertion opening 2 of the bottom wall 3 is preferably smaller than the outer diameter of the stud base 12. Furthermore, it is preferable that the side wall 4 has an inner surface 6 that closely contacts the outside of the stud attachment jig 7. With such a structure, the stud main body 11 accommodated in the stud mounting jig 7 is sealed by the spatter adhesion prevention jig 1 and the stud base 12, and is placed in a state isolated from the welding location. . Therefore, even if spatter occurs in and around the welding location, the spatter 24 and fume 25 can be prevented from adhering to the surface of the stud body 11.

In the spatter adhesion prevention jig according to the present embodiment, the bottomed cylindrical member is preferably made of a rubber material or a felt material. As the rubber material, nitrile rubber, acrylic rubber, silicone rubber, fluororubber, ethylene vinyl acetate rubber, etc. can be used.

(Means for preventing spatter adhesion to objects to be welded)
Spatter also adheres to the surface of the workpiece after welding. When preventing spatter adhesion to the object to be welded, an adhesion prevention sheet 30 as shown in FIG. 4 can be used. As shown in FIG. 4A, the adhesion prevention sheet 30 has a disc shape with a certain thickness, and has a hole 31 in the center into which a stud bolt 33 can be inserted. The planar shape of the sheet may be polygonal in addition to circular, and may be changed as appropriate depending on the location where it is used. Further, although this is not an essential shape, recesses 32 as shown in FIG. 3 may be provided at a plurality of locations on the outer periphery of the sheet so as not to interfere with the support member of the stud welding gun.

When using the adhesion prevention sheet, place it at the location where the studs are to be joined on the object to be welded, and then bring the stud welding gun with the stud attached close to the object to be welded. Perform stud welding. FIG. 4B is a diagram schematically showing the form after welding. Spatter 24 generated during welding is deposited on the adhesion prevention sheet 30. Therefore, by removing the adhesion prevention sheet 30 after welding, spatter adhesion to the welded object can be easily prevented.

As the material for the adhesion prevention sheet, the same rubber material or felt material as the sputter adhesion prevention jig according to the present invention can be used. The thickness can be 1.0 to 2.0 mm and the diameter can be 30 to 50 mm.

Examples of the present invention will be described below. The present invention is not limited to the following examples.

Stud welding was performed using stud bolts. As the stud bolt, a straight type M8 manufactured by Nippon Drive It Co., Ltd. was used. The material of the stud bolt was mild steel.

As the object to be welded, a zinc-based plated steel sheet having a plating layer having a composition of Zn-6%AL-3%Mg in mass % was used. The plate thickness was 2.3 mm, and the coating weight was 90 g/m ² on one side. The above-mentioned plated steel plate was cut into a 100 mm x 100 mm rectangle to prepare a test steel plate. At the end face of the test steel plate, the surface of the base material was exposed.

For stud welding, a CD stud welding machine (JDI-80) manufactured by Nippon Drive-It Co., Ltd. was used as a capacitor stud welding machine. The stud bolts held in the stud mounting jig of the stud welding gun (H100) manufactured by Nippon Drive-It Co., Ltd. are on the positive side (anode side), and the test steel plate is on the negative side (cathode side). The wiring was connected to the DC power supply of the stud welding machine.

For the wiring to be connected to the test steel plate, the electrode of the energizing jig was brought into contact with the end face of the test steel plate so as to be pressed against the end face side. The pressing force at that time was 68N. The set voltage during welding was 160V.

As a spatter adhesion prevention jig corresponding to the present invention, a bottomed cylindrical member made of nitrile rubber and having a thickness of 2.5 mm, an outer diameter of 15 mm, and a height of 15 mm was prepared. I attached it to the stud mounting jig of the stud welding gun. As an example of the present invention using this stud welding gun, stud welding was performed to join a stud bolt to a test steel plate under the above welding conditions. On the other hand, as a comparative example, stud welding was performed under similar welding conditions without attaching anything to the stud mounting jig.

The surface of the stud bolt after welding was visually observed. Furthermore, the tightened state of the nut was confirmed by tightening the nut onto the stud bolt.

According to these results, no spatter or fume was observed on the surface of the stud bolt in the example of the present invention. Furthermore, I was able to tighten the nuts normally. On the other hand, in the comparative example, adhesion of spatter and fume was observed on the surface of the stud bolt. Furthermore, the nut could not be tightened.

As described above, the stud welding method according to the present invention and the spatter adhesion prevention jig used therein can prevent spatter and fume from adhering to the stud surface after welding, and can prevent other parts from attaching to the welded stud. It is useful in that it can be attached. The present invention is useful in that such useful effects can be achieved by a simple means of attaching the spatter prevention jig to the stud mounting jig of the stud welding gun.

1 Spatter adhesion prevention jig 2 Insertion port 3 Bottom wall 4 Side wall 5 Inner surface (bottom wall)
6 Inner surface (side wall)
7 Stud mounting jig 8 First opening 9 Second opening 10 Stud 11 Stud body 12 Stud base 13 Projection 14 Slit 15 Band 16 Roundness 20 Object to be welded 21 Stud welding gun 22 Stopper 23 Arc 24 Spatter 25 Fume 26 Plated steel plate 27 Plating Layer 30 Adhesion prevention sheet 31 Hole 32 Recess 33 Stud bolt 34 Stud welder 35 Wiring 36 Earth wiring 37 Support stand

Claims (3)

A stud welding method for welding a workpiece and a stud using a stud welding gun, the method comprising:
The stud welding gun includes a stud mounting jig that holds the stud,
The stud includes a stud body and a stud base, and the stud base has a larger outer diameter than the stud body,
The stud mounting jig is a cylindrical member having a first opening at one end into which the stud body can enter, and a second opening at the other end into which a stopper that contacts the end surface of the stud body can be inserted. ,
It is composed of a bottomed cylindrical member having a bottom wall and a side wall, and the bottom wall is provided with an insertion opening having an inner diameter smaller than the outer diameter of the stud base and into which the stud body can be inserted, and the stud body is inserted into the stud base. The spatter adhesion prevention jig has an inner surface that comes into close contact with the tip side of the jig, and the side wall has an inner surface that comes into close contact with the outside of the stud mounting jig. 1 Stud welding method that is attached to the opening side and welded. A spatter adhesion prevention jig attached to a stud mounting jig of a stud welding gun for welding a workpiece and a stud,
It is composed of a bottomed cylindrical member having a bottom wall and a side wall,
The stud includes a stud body and a stud base, and the stud base has a larger outer diameter than the stud body,
The bottom wall is provided with an insertion opening into which the stud body can be inserted, and has an inner surface that comes into close contact with the distal end side of the stud mounting jig, and the inner diameter of the insertion opening of the bottom wall is equal to that of the stud base. It is smaller than the outer diameter,
The side wall has an inner surface that closely contacts the outside of the stud mounting jig.
Jig for preventing spatter adhesion. The jig for preventing spatter adhesion according to claim 2, wherein the bottomed cylindrical member is made of a rubber material or a felt material.

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