JP6929507B2 - Electrode for electric resistance welding - Google Patents

Description

In the present invention, an advancing / retreating member composed of a large-diameter portion, a medium-diameter portion, and a guide pin is inserted into a guide hole formed in the electrode body, which is composed of a large-diameter hole, a medium-diameter hole, and a small-diameter hole, and interrupts the flow of cooling air. It relates to electrodes for electric resistance welding.

The electrodes for electric resistance welding described in JP-A-2002-248578, JP-A-2017-006982, JP-A-2017-047469, and JP-A-2017-1366639 have large-diameter holes in the electrode body. , A guide hole consisting of a medium-diameter hole and a small-diameter hole is formed, and a sliding portion made of a synthetic resin material with a guide pin is fitted into the guide hole, and a sliding portion is formed on an inner end surface formed in a part of the guide hole. The end faces formed in the above are in close contact with each other to block the flow of cooling air, and the end face is separated from the inner end face to allow the flow of cooling air.

JP-A-2002-248578 JP-A-2017-006982 JP-A-2017-047469 Japanese Unexamined Patent Publication No. 2017-136639

In the technique described in the above patent document, no consideration is given to the countermeasure when the steel plate component placed on the electrode hits the guide pin. The steel plate part to be inserted by the operator is provided with a pilot hole through which the guide pin penetrates. A force in the tilting direction or the radial direction acts on the sliding part, which causes elastic deformation of the sliding part and causes the center position of the guide pin to be deviated, or the adhesion of the sliding part is impaired and air leakage occurs. Occurs.

The present invention has been provided in order to solve the above-mentioned problems. The advancing / retreating member composed of a large-diameter portion, a medium-diameter portion, and a guide pin is composed of a single metal material member, and the part becomes an advancing / retreating member. An electrode for electric resistance welding whose contact point is an insulating structure.

The invention according to claim 1
The electrode body with a circular cross section is constructed using a copper alloy.
A guide hole consisting of a large-diameter hole, a medium-diameter hole, and a small-diameter hole is formed in the electrode body.
The advancing / retreating member having a circular cross section inserted into the guide hole can slide with the large-diameter portion fitted in a state where the large-diameter hole can slide with substantially no gap, and the medium-diameter hole with substantially no gap. It is composed of a medium diameter part that is fitted in the state and a guide pin that protrudes from the end face of the electrode body on which the steel plate component is placed and penetrates the pilot hole of the steel plate component.
When the guide pin is pushed down, a ventilation gap through which the cooling air passes is formed between the small diameter hole and the guide pin.
The movable end surface formed at the boundary between the medium diameter portion and the large diameter portion of the advancing / retreating member is configured to be in close contact with the stationary inner end surface formed at the boundary between the medium diameter hole and the large diameter hole of the guide hole. At the same time, the stationary inner end face and the movable end face are arranged on a virtual plane where the central axes of the electrode body intersect vertically.
The length of the electrode body in which the medium-diameter part is fitted into the medium-diameter hole in the central axis direction is set shorter than the length at which the guide pin retracts during welding.
A pressurizing means for pressing the movable end face against the stationary inner end face is arranged in the guide hole.
The advancing / retreating member is composed of a single metal material member and is composed of a single metal material member.
It is an electrode for electric resistance welding characterized in that an insulating structure is adopted at a position where a projection nut or a projection bolt comes into contact with an advancing / retreating member.

The advancing / retreating member having a circular cross section inserted into the guide hole can slide with the large-diameter portion fitted in a state where the large-diameter hole can slide with substantially no gap, and with the medium-diameter hole having substantially no gap. It is composed of a medium diameter part that is fitted in the state and a guide pin that protrudes from the end face of the electrode body on which the steel plate component is placed and penetrates the prepared hole of the steel plate component, and the advancing / retreating member is a single metal material member. Insulation structure is adopted at the place where parts such as projection nuts and projection bolts come into contact with the advancing / retreating member.

The steel plate part to be inserted by the operator is provided with a pilot hole through which the guide pin penetrates. A force in the tilting direction or the radial direction acts on the guide pin, which causes the advancing / retreating member to elastically deform. When such elastic deformation occurs, the guide pin is eccentric with respect to the central axis of the electrode body, and parts such as projection are welded to the steel plate part while the pilot hole of the steel plate part is in contact with the eccentric guide pin. .. In this case, the screw hole and the prepared hole of the nut are not concentric, and in some cases, the bolt cannot be screwed in.

In the present invention, since the large-diameter portion and the medium-diameter portion of the advancing / retreating member slide into the large-diameter hole or the medium-diameter hole, the advancing / retreating member is in a state of being supported at two points. Further, the advancing / retreating member is composed of a single metal material member, and an insulating structure is adopted at a position where parts such as a projection nut and a projection bolt come into contact with the advancing / retreating member.

Due to the above two-point support state and the configuration from a single metal material member, even if an external force in the radial or tilting direction acts on the advancing / retreating member, the displacement of the advancing / retreating member in the tilting direction is substantially a problem. The amount is reduced to the extent that it does not become. That is, since the entire advancing / retreating member is made of a metal material, the elastic deformation of the large-diameter portion and the medium-diameter portion becomes very small, and the eccentricity of the guide pin becomes a level that does not substantially matter. Therefore, the problem of defective welding position due to eccentricity as described above is solved. In particular, the configuration from a single metal material member minimizes the elastic deformation of the entire advancing / retreating member, so that the eccentricity amount can be set to a level that does not substantially matter.

Furthermore, since the misalignment of the advancing / retreating member is minimized, the state of close contact between the stationary inner end surface and the movable end surface is surely maintained, the flow of cooling air is surely blocked during welding standby, and there is an economic problem due to air leakage. And the noise problem is solved.

The advancing / retreating member is manufactured from a single metal material member in the state of a so-called one-piece part, and an insulating structure is adopted in a local part where insulation is required. Therefore, since it is only necessary to manufacture the one-piece type advancing / retreating member that does not require assembling a plurality of parts and to insulate the necessary parts, the manufacturing of the advancing / retreating member is simplified, which is advantageous for improving the dimensional accuracy of each part. In particular, since the insulation treatment structure applied to the advancing / retreating member can be limited to the range where the parts come into contact, the range of insulation treatment can be minimized, which is easy to manufacture and effective in terms of cost. Is.

In the structure described in the above-mentioned patent document, since the portion corresponding to the large-diameter portion and the medium-diameter portion of the advancing / retreating member is composed of the insulating synthetic resin, the synthetic resin portion and the metal guide pin are integrated. Becomes complicated. However, in the present invention, the problem of complication is solved as described above. Further, since the structure is so-called local insulation, the insulation structure can be simplified.

It is sectional drawing of each part of the whole electrode, and sectional drawing of the advancing / retreating member. It is sectional drawing in the case of a projection bolt.

Next, a mode for carrying out the electrode for electric resistance welding according to the present invention will be described.

1 and 2 show examples of the present invention.

First, the electrode body will be described.

The electrode body 1 made of a conductive metal material made of a copper alloy such as chrome copper has a cylindrical shape and a circular cross section, and a fixing portion 2 to be inserted into the stationary member 11 and a steel plate component 3 are placed therein. The cap portion 4 to be formed is joined at the screw portion 5 to form an electrode body 1 having a circular cross section. A guide hole 6 having a circular cross section is formed in the electrode body 1, and a large-diameter hole 7 formed in the fixing portion 2 and a cap portion 4 having a diameter smaller than the large-diameter hole 7 are formed in the guide hole 6. A medium-diameter hole 8 and a small-diameter hole 9 having a diameter smaller than that of the medium-diameter hole 8 are formed, and the large-diameter hole 7, the medium-diameter hole 8, and the small-diameter hole 9 are aligned on the central axis OO of the electrode body 1. It is arranged in a coaxial state.

Next, the advancing / retreating member will be described.

On the other hand, the advancing / retreating member 50 is inserted into the guide hole 6. The advancing / retreating member 50 is a member having a circular cross section, and is composed of a large diameter portion 13, a medium diameter portion 14 having a diameter smaller than that of the large diameter portion 13, and a guide pin 15 having a diameter smaller than that of the medium diameter portion 14. ..

The large-diameter portion 13 is fitted in the large-diameter hole 7 in a slidable state with substantially no gap. The medium-diameter portion 14 is fitted in the medium-diameter hole 8 in a slidable state with substantially no gap. The guide pin 15 penetrates the small diameter hole 9 and projects from the end surface of the electrode body 1 on which the steel plate component 3 is placed. Then, a ventilation gap 16 through which the cooling air passes when the guide pin 15 is pushed down is formed between the small diameter hole 9 and the prepared hole 10 of the steel plate component 3.

The above-mentioned "... in a state where the sliding member can be slid without a gap ..." means that even if a force in the radial direction of the electrode body 1 is applied to the advancing / retreating member 50, there is a rattling feeling with a gap. It means a state in which there is no feel and the sliding in the central axis OO direction is possible.

The large-diameter portion 13, the medium-diameter portion 14, and the guide pin 15 are integrally formed in a one-piece state, as shown in FIG. 1 (C) in the most understandable manner. Such a configuration may be a case of processing a single metal material member or a case of molding by casting and finishing, and here, the former case is adopted.

That is, one stainless steel material having a circular cross section is machined by cutting or the like to mold the large diameter portion 13, the medium diameter portion 14, and the guide pin 15.

Next, the parts and the insulating structure will be described.

The nut 17 is for projection welding (projection nut), and a screw hole 18 is formed in the center of a square main body, and welding protrusions 19 are provided at four corners. The open end of the screw hole 18 is engaged with the tapered portion 20 of the guide pin 15. Since the nut 17 is in a state of floating from the steel plate component 3 in this way, a length L1 at which the guide pin 15 retracts is retained when the movable electrode 21 advances and welds.

The dimensions of each part of the projection nut 17 vary depending on the size and scale of the electrodes. Here, a square projection nut 17 having a length and a width of 12 mm and a thickness of 7.2 mm is electrically resistance welded to a steel plate component 3 having a thickness of 0.7 mm.

The length of the electrode body in which the medium-diameter portion 14 is fitted into the medium-diameter hole 8 in the central axis OO direction is set to be shorter than the length L1 in which the guide pin 15 retracts during welding. In this embodiment, the tapered portion 22 is formed on the upper portion of the medium diameter portion 14, and the length in the central axis OO direction in which the medium diameter portion 14 is fitted into the medium diameter hole 8 includes the tapered portion 22. There is no length L2. Therefore, the length L2 in the central axis OO direction of the electrode body in which the medium-diameter portion 14 is fitted into the medium-diameter hole 8 is set shorter than the length L1 in which the guide pin 15 retracts during welding. .. When the guide pin 15 is pushed down, a ventilation gap is first formed between the tapered portion 22 and the medium diameter hole 8.

As shown in FIG. 1D, a small-diameter approach portion 24 that enters the screw hole 18 of the nut 17 is formed at the tip of the guide pin 15, and an insulating layer is formed on the entire outer surface of the tapered portion 20 and the entry portion 24. 25 is formed as an insulating structure.

The insulating layer 25 is a method of coating a ceramic material, a method of manufacturing the entire advancing / retreating member 50 with a special stainless alloy and heat-treating a necessary portion to form a high-hardness insulating film, and a method of fitting a ceramic cap member. It can be formed by such as. Various types of the above-mentioned special stainless alloys are commercially available, and the material of Toshiba Materials Co., Ltd. is one of them, and is generally called "KCF". The insulating layer 25 in this embodiment is a coating method of a ceramic material containing silicon nitride as a main component.

By adopting the insulating structure as described above, the movable electrode 21 advances, the nut 17 and the steel plate component 3 are sandwiched between the electrode body 1, and the welding current is energized. At this time, since the energization from the insulating layer 25 is blocked, the current flows from the welding projection 19 to the steel plate component 3, and good welding is performed. As shown in FIGS. 1A and 1D, when the approaching portion 24 does not protrude from the screw hole 18, the insulating structure at the top of the approaching portion 24 can be stopped, but the approaching portion 24 has a screw hole. When the movable electrode 21 protrudes from 18 and comes into contact with the top of the approach portion 24, the top also has an insulating structure as shown in FIG. 1 (D).

Next, the intermittent structure of the cooling air will be described.

A vent 26 is formed to guide the cooling air to the guide hole 6. In order to secure an air passage at the sliding portion between the large diameter portion 13 and the large diameter hole 7, a concave groove in the central axis OO direction can be formed on the outer peripheral surface of the large diameter portion 13, but here, the large diameter portion 13 is large. A flat surface portion 27 in the central axis OO direction is formed on the outer peripheral surface of the diameter portion 13, and an air passage 28 composed of the flat surface portion 27 and the arc-shaped inner surface of the large diameter hole 7 is formed. Such flat surfaces 27 are formed at 90-degree intervals, and air passages are provided at four locations.

The compression coil spring 31 is fitted between the advancing / retreating member 50 and the inner bottom surface of the guide hole 6, and the tension thereof acts on the advancing / retreating member 50. The tension of the compression coil spring 31 establishes the consolidation of the movable end surface with respect to the stationary inner end surface, which will be described later. The compression coil spring 31 is a pressurizing means, and the pressure of compressed air can be used instead.

An annular stationary inner end surface 29 is formed at the boundary between the medium-diameter hole 8 and the large-diameter hole 7 of the guide hole 6. Further, an annular movable end face 30 is formed at the boundary between the medium diameter portion 14 and the large diameter portion 13 of the advancing / retreating member 50. The stationary inner end surface 29 and the movable end surface 30 are arranged on a virtual plane in which the central axis OO of the electrode body 1 intersects vertically, and the movable end surface 30 with respect to the stationary inner end surface 29 due to the tension of the compression coil spring 31. It adheres in an annular state, and the cooling air is sealed by this adhesion.

Next, other cases will be described.

The above case is the case of the projection nut, but the case shown in FIG. 2 is the case of the projection bolt. The projection bolt 33 is composed of a shaft portion 34 on which a male screw is formed, a circular flange 35 integrated with the shaft portion 34, and a welding projection 36 provided on the lower surface of the flange 35. The guide pin 15 has a hollow tubular shape and is provided with a receiving hole 37 into which the shaft portion 34 is inserted.

As shown in FIG. 2B, the points where the parts in this case come into contact with the advancing / retreating member 50 are the inner peripheral surface and the bottom surface of the receiving hole 37, so that the insulating structure 25 is formed on these surfaces. Here, a ceramic solution is applied to the inner peripheral surface and the bottom surface and cured. The other configurations are the same as in the previous case including the parts not shown, and the same reference numerals are given to the members having the same functions.

Next, the operation of the electrodes will be described.

FIG. 1A shows a state in which the movable end surface 30 is in close contact with the stationary inner end surface 29 due to the tension of the compression coil spring 31 to block the flow of cooling air.

When the movable electrode 21 advances and the interval L1 disappears, the medium-diameter portion 14 that has entered the medium-diameter hole 8 escapes from the medium-diameter hole 8 to form a passage for cooling air. The cooling air is released to the outside through the vent 26, the air passage 28, the medium diameter hole 8, and the ventilation gap 16 and through the gap between the lower surface of the nut 17 and the steel plate component 3. This air flow eliminates impurities such as spatter in the direction away from the electrodes. When the guide pin 15 is pushed down, the tapered portion 22 first forms an air passage. Due to the inclination of the tapered portion 22, an air passage having a large flow path area is formed at an initial stage, which is suitable for reliable flow of cooling air. Further, when the guide pin 15 returns, the medium diameter portion 14 smoothly enters the medium diameter hole 8 by the guide function of the tapered portion 22. The same operation is performed for the projection bolt 33 shown in FIG.

The effects of the examples described above are as follows.

There is a substantially gap between the large-diameter portion 13 into which the advancing / retreating member 50 having a circular cross section inserted into the guide hole 6 is fitted into the large-diameter hole 7 so that it can slide without a gap, and the medium-diameter hole 8. It is composed of a medium-diameter portion 14 that is fitted in a slidable state without it, and a guide pin 15 that protrudes from the end face of the electrode body 1 on which the steel plate component 3 is placed and penetrates the prepared hole 10 of the steel plate component 3. The advancing / retreating member 50 is composed of a single metal material member, and an insulating structure 25 is adopted at a position where parts such as the projection nut 17 and the projection bolt 33 come into contact with the advancing / retreating member 50.

The steel plate component 3 to be inserted by the operator is provided with a pilot hole 10 through which the guide pin 15 penetrates, so that the inner peripheral portion of the pilot hole 10 abuts on the guide pin 15 or the outer end portion of the steel plate component 3 guides. When it hits the pin 15, a force in the tilting direction or the diametrical direction acts on the guide pin 15, which causes the advancing / retreating member 50 to elastically deform. When such elastic deformation occurs, the guide pin 15 is eccentric with respect to the central axis OO of the electrode body 1, and the projection nut 17 or the like is formed while the pilot hole 10 of the steel plate component 3 is in contact with the eccentric guide pin 15. Is welded to the steel plate part 3. If this happens, the screw hole 18 and the pilot hole 10 of the nut 17 will not be in a concentric state, and in some cases, the bolt cannot be screwed in.

In this embodiment, since the large-diameter portion 13 and the medium-diameter portion 14 of the advancing / retreating member 50 are slid on the 7 large-diameter holes and the medium-diameter holes 8, the advancing / retreating member 50 is in a state of being supported at two points. It has become. Further, the advancing / retreating member 50 is composed of a single metal material member, and an insulating structure 25 is adopted at a position where parts such as the projection nut 17 and the projection bolt 33 come into contact with the advancing / retreating member 50.

Due to the above-mentioned two-point support state and the configuration from a single metal material member, even if an external force in the radial direction or the inclination direction acts on the advance / retreat member 50, the displacement of the advance / retreat member 50 in the inclination direction is substantially present. The amount is reduced to the extent that it does not cause any problems. That is, since the entire advancing / retreating member 50 is made of a metal material, the elastic deformation of the large-diameter portion 13 and the medium-diameter portion 14 becomes very small, and the amount of eccentricity of the guide pin 15 becomes a level that does not substantially matter. .. Therefore, the problem of defective welding position due to eccentricity as described above is solved. In particular, the configuration from a single metal material member minimizes the elastic deformation of the entire advancing / retreating member 50, so that the eccentricity amount can be set to a level that does not substantially matter.

Further, since the misalignment of the advancing / retreating member 50 is minimized, the close contact state between the stationary inner end surface 29 and the movable end surface 30 is surely maintained, the flow of cooling air is surely cut off during the waiting for welding, and the economy due to air leakage is achieved. Sexual problems and noise problems are solved.

The advancing / retreating member 50 is manufactured from a single metal material member in the state of a so-called one-piece part, and an insulating structure 25 is adopted in a local part where insulation is required. Therefore, since it is only necessary to manufacture the one-piece type advancing / retreating member 50 that does not require assembling a plurality of parts and to insulate the necessary parts, the manufacturing of the advancing / retreating member 50 is simplified, which is advantageous for improving the dimensional accuracy of each part. In particular, since the insulation treatment structure applied to the advancing / retreating member 50 can be limited to the range where the parts come into contact with each other, the range of the insulation treatment can be minimized, and it is easy to manufacture and cost effective. It is valid.

In the structure described in the above-mentioned patent document, since the portion corresponding to the large diameter portion 13 and the medium diameter portion 14 of the advancing / retreating member 50 is made of an insulating synthetic resin material, the synthetic resin portion and the metal guide pin are formed. The integrated structure of is complicated. However, in the present invention, as described above, since the insulating structure can be adopted only locally in the advancing / retreating member 50 of the integrated structure, the problem of complication is solved. Further, since the structure is so-called local insulation, the insulation structure can be simplified.

As described above, according to the electrode for electric resistance welding of the present invention, the advancing / retreating member composed of a large-diameter portion, a medium-diameter portion, and a guide pin is composed of a single metal material member, and the parts come into contact with the advancing / retreating member. The location has an insulating structure. Therefore, it can be used in a wide range of industrial fields such as a body welding process for automobiles and a sheet metal welding process for home appliances.

1 Electrode body 3 Steel plate parts 6 Guide holes 7 Large diameter holes 8 Medium diameter holes 9 Small diameter holes 10 Pilot holes 13 Large diameter parts 14 Medium diameter parts 15 Guide pins 16 Ventilation gaps 17 Projection nuts 21 Movable electrodes 25 Insulation layer, insulation structure 28 Air passage 29 Static inner end surface 30 Movable end surface 33 Projection nut 37 Receiving hole 50 Advance / retreat member OO Center axis L1 Guide pin retreat length L2 Medium diameter part insertion length

Claims (1)

The electrode body with a circular cross section is constructed using a copper alloy.
A guide hole consisting of a large-diameter hole, a medium-diameter hole, and a small-diameter hole is formed in the electrode body.
The advancing / retreating member having a circular cross section inserted into the guide hole can slide with the large-diameter portion fitted in a state where the large-diameter hole can slide with substantially no gap, and the medium-diameter hole with substantially no gap. It is composed of a medium diameter part that is fitted in the state and a guide pin that protrudes from the end face of the electrode body on which the steel plate component is placed and penetrates the pilot hole of the steel plate component.
When the guide pin is pushed down, a ventilation gap through which the cooling air passes is formed between the small diameter hole and the guide pin.
The movable end surface formed at the boundary between the medium diameter portion and the large diameter portion of the advancing / retreating member is configured to be in close contact with the stationary inner end surface formed at the boundary between the medium diameter hole and the large diameter hole of the guide hole. At the same time, the stationary inner end face and the movable end face are arranged on a virtual plane where the central axes of the electrode body intersect vertically.
The length of the electrode body in which the medium-diameter part is fitted into the medium-diameter hole in the central axis direction is set shorter than the length at which the guide pin retracts during welding.
A pressurizing means for pressing the movable end face against the stationary inner end face is arranged in the guide hole.
The advancing / retreating member is composed of a single metal material member and is composed of a single metal material member.
An electrode for electric resistance welding characterized in that an insulating structure is adopted where the projection nut and projection bolt come into contact with the advancing / retreating member.

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