JP2007125602A - Method and apparatus for resistance welding, and material to be welded - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily perform projection welding on a material to be welded with one surface covered with an electrical insulation film, and to obtain high welding quality such as desired welding strength and small weld marks. <P>SOLUTION: A resistance welding method is used to weld a surface covered with an electrical insulation film of a first material 1 to be welded on a conductive surface of a second material 2 to be welded. In the method, a projection P projected on the one side surface covered with the electrical insulation film of the first material 1 is provided. The electrical insulation film at the tip is removed, so that the electrical insulation film is broken to expose the conductive surface at the tip. The conductive surface at the tip is brought into contact with the conductive surface of the second material. As a result, at the tip of the projection P, the conductivity between the first material 1 and the second material 2 is secured, and the projection welding is performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a welding method, a resistance welding apparatus, and a specific welded object for resistance welding of a first workpiece to be welded made of a metal plate whose one side is coated with an electrical insulating film and an arbitrary second workpiece. About.

There is a case where it is desired to resistance-weld insulating coated steel sheets coated on one side with an electric insulating film made of a thermoplastic resin or the like, or such an insulating coated steel sheet and an arbitrary workpiece to which no insulating coating is applied. In such a case, since the electric insulating film disturbs and does not energize, it is necessary to break the electric insulating film and secure the conductivity between the workpieces prior to resistance welding. In the conventional case, the electrical insulating film of the insulating coated steel sheet is positioned on the upper side, and the metal surfaces are overlapped so that the metal surfaces come into contact with each other, and the electric insulating film is first broken by the welding electrode having a sharp protrusion. A method is disclosed in which resistance is welded by energization after ensuring that the protrusion tip reaches the metal surface and thereby ensuring conductivity between the workpieces (see, for example, Patent Document 1). As another welding method, the first high voltage pulse is applied to break the electrical insulating film to ensure the conductivity between the workpieces, and then the second high voltage pulse is energized. A method of resistance welding is also disclosed (for example, see Patent Document 2). Another resistance welding method that can solve the following problems of the above-mentioned welding methods has already been disclosed. In this welding method, a hole is formed in advance in the welded portion of the insulation-coated steel sheet that is one of the objects to be welded, and a protrusion is formed on the metal plate that is the other object to be welded. Both workpieces are overlapped and resistance-welded so that the tip of the protrusion enters the hole (see, for example, Patent Document 3).
JP 2000-263248 A JP 2004-130331 A JP 05-154667 A

  However, in the resistance welding method disclosed in the above-mentioned Patent Document 1, the welding electrode on the side that breaks the electrical insulating film includes an electrode tip that is sharp enough to break the electrical insulating film. The tip of the electrode tip must be a small point or a thin line. Therefore, it is not possible to flow a large welding current that rapidly increases as in the case of capacitor storage type resistance welding, and the resistance welding is limited to a welding current with a very small capacity. Furthermore, in resistance welding, since the minimum required pressure is applied between the two welding electrodes, the tip of the electrode tip is damaged or deformed by the welding current and the pressure applied between the welding electrodes. Since it is easy, the electric insulating film cannot be broken immediately. Therefore, in order to ensure the electrical conductivity between the two workpieces, the electrode tips must be frequently replaced, and it is difficult to employ such a resistance welding method for actual welding operations.

  Further, in the resistance welding method disclosed in the above-mentioned Patent Document 2, an extremely minute hole is formed by applying the first high voltage pulse, but there is an electrical insulating film between both workpieces. Therefore, it is difficult for the workpieces to come into contact with each other depending on the thickness of the electrical insulating film, and it is often difficult to ensure conductivity between the workpieces. Furthermore, this resistance welding method requires two pulse generation circuits for generating the first and second high voltage pulses, which is also problematic in terms of economy. Further, since a high voltage pulse is used, there is a drawback that there is a problem in safety.

  The resistance welding method disclosed in Patent Document 3 does not cause the problems of Patent Documents 1 and 2, but one workpiece is provided with holes and the other workpiece is provided with protrusions. Need to be aligned. The height of the protrusion is generally around 1 mm in normal projection welding, and in the actual welding process, both workpieces are overlapped with the protrusion having such a height aligned with the hole. It is very difficult to press and weld. In particular, when there are a plurality of holes and protrusions, it is difficult to weld the corresponding holes and protrusions so that they are not misaligned, and an expensive detection / alignment mechanism and misalignment prevention mechanism are required. There is a problem in terms of economy.

  Therefore, the present invention solves the above-mentioned problems, and by forming a new special projection at the welding location by a simple method, it ensures the conductivity between the workpieces and at the same time, the welding mark The main purpose is to provide a resistance welding method and apparatus capable of obtaining a high-quality resistance welding result such as being small and having excellent welding strength, and further to provide an article to be welded.

  In order to solve the problems as described above, the first invention makes one surface side covered with the electrical insulating film of the first work piece contact the conductive surface of the second work piece, In a resistance welding method in which welding is performed by passing a welding current between the first workpiece and the second workpiece in a state where the space between them is pressurized, the first workpiece is welded. The projection is provided on the one surface side covered with the electrical insulating film, and the tip of the projection penetrates, so that the electrical insulation film is broken at the tip and the conductive surface. Is exposed, and the conductive surface of the tip of the projection in the first workpiece is in contact with the conductive surface of the second weld, so that the first at the tip of the projection is the first Conductivity is ensured between the workpiece to be welded and the second workpiece to be welded. There is provided an anti-welding method.

  According to a second invention, in the first invention, a tip surface of the projection formed on the first work piece is a small annular conductive surface having an arbitrary shape, and the projection is a ring. The present invention provides a resistance welding method characterized by acting as a projection.

  According to a third invention, in the first invention or the second invention, the inner surface of the through hole formed when the tip of the protrusion penetrates has a tapered surface that narrows in the direction of the protrusion. The present invention provides a resistance welding method characterized by comprising a thin cylindrical surface extending from a tapered portion.

  According to a fourth invention, there is provided the resistance welding method according to the third invention, wherein the angle of the tapered surface is in the range of 40 to 80 degrees.

  In a fifth aspect of the present invention, the one surface side covered with the electrical insulating film of the first workpiece is brought into contact with the conductive surface of the second workpiece, and a pressure is applied between them. In the resistance welding method of welding by energizing a welding current between the first workpiece and the second workpiece, the one covered with the electrical insulating film of the first workpiece A protrusion projecting on the surface side of the protrusion, and by removing the electrical insulating film at the tip of the protrusion, the electrical insulating film is broken at the tip to expose the conductive surface, When the conductive surface of the tip of the projection in the first workpiece is in contact with the conductive surface of the second weld, the first workpiece and the weld at the tip of the projection Provided is a resistance welding method characterized in that conductivity is ensured between the second workpiece and the workpiece. Is shall.

  According to a sixth aspect of the present invention, there is provided a first welding electrode that contacts the first workpiece, a second welding electrode that contacts the second workpiece, the first welding electrode, and the second welding. A welding power source for passing a welding current between the first workpiece and the second workpiece through the electrode, and being covered with an electrical insulating film of the first workpiece The first welding object and the second welding object are energized by passing the welding current in a state where the surface side of the first electrode is brought into contact with the conductive surface of the second welding object and the pressure is applied between them. In a resistance welding apparatus for welding an object, a through-hole comprising a perforated portion having a tip portion tapered at a predetermined angle and a tapered portion extending from the perforated portion in a conical or pyramidal shape at a predetermined angle Prior to resistance welding, the first portion to be welded with the through hole / projection formation jig is provided with a projection formation jig. A through-hole is opened to break the electrical insulating film side, and a tapered surface centering on the through-hole is formed to form a projecting portion projecting to the electrical insulating film side. A resistance welding apparatus is provided that welds the first and second workpieces to contact with the conductive surface of the workpiece.

  According to a seventh aspect of the present invention, a workpiece to be welded whose one surface side is covered with an electrical insulating film includes a protrusion that protrudes toward the one surface that is covered with the electrical insulating film. A tip to be penetrated or the electrical insulating film at the tip of the protrusion is removed, and the electrical insulating film is broken at the tip to expose a conductive surface. It provides things.

  An eighth invention provides an object to be welded according to the seventh invention, wherein a tip end surface of the protrusion is a small annular conductive surface or a small conductive surface having an arbitrary shape. is there.

  According to the first to fifth inventions, projection welding can be easily performed even if one of the workpieces or both surfaces of the workpieces are covered with an electrical insulating film. Provided is a resistance welding method capable of obtaining a welding result with high welding quality such as a desired welding strength and small welding marks. In particular, according to the second aspect of the present invention, since the tip surface of the protrusion is a small annular conductive surface having an arbitrary shape, the substantial projection area is small even though the contact area of the tip of the protrusion is small. A resistance welding method capable of improving the welding strength to increase the size is provided.

  According to the sixth aspect of the invention, even if either one of the workpieces or both surfaces of the workpieces are covered with the electrical insulating film, the projection welding can be easily performed and desired. It is possible to provide a resistance welding apparatus capable of obtaining a welding result having a high welding quality such as a welding strength and a small welding mark.

  In addition, according to the seventh and eighth inventions, even if the object to be welded is covered with an electrical insulating film, projection welding can be easily performed, and desired welding strength and small welding traces can be obtained. For example, it is possible to provide an object to be welded with high welding quality.

[Embodiment 1]
Embodiment 1 of the resistance welding and work piece according to the present invention will be described with reference to FIGS. FIG. 1 is a diagram for explaining a resistance welding method according to the first embodiment, and FIG. 2 is a through-hole for forming a protrusion having a through-hole in a workpiece to be welded made of a metal plate having an electric insulating film formed on one side. FIG. 3 is a diagram for explaining a hole / projection forming jig, and FIG. 3 is a method for forming a projection having a through hole in the first workpiece using the through hole / projection forming jig; It is a figure which shows the projection part which has a through-hole. The first and second workpieces 1 and 2 are insulating coated metal plates such as ordinary insulating coated steel plates having an electric insulating film formed on one side, and the first workpiece 1 has a relatively thin thickness. It comprises a metal plate 1A and an electrical insulating film or semi-electrical insulating film (herein referred to as an electrical insulating film) 1B formed on one surface thereof. The second work piece 2 is the same as the first work piece 1 or an insulation-coated metal plate or the like having a thickness or material different from that of the first work piece 1. It consists of the formed electrical insulation film 2B.

  As shown in FIG. 1, the first workpiece 1 is overlaid so that the electrical insulating film 1 </ b> B is in contact with the metal member 2 </ b> A of the second workpiece 2. The second workpiece 2 is placed on a placing table 3 made of an electrically insulating material so that the electrically insulating film 2B is on the lower side. The first workpiece 1 is provided with a protrusion P having a through hole H, which will be described in detail later. At the time of welding, the first welding electrode 4 pressurizes the metal plate 1A including the protrusion P of the first workpiece 1 with a predetermined pressure, and the second welding electrode 5 is a second welding target. It contacts the metal plate 2A of the object 2. The first and second welding electrodes 4 and 5 are connected to a welding power source 6. The welding power source 6 includes a single-phase or three-phase commercial AC power source 7, a rectifier circuit 8 that rectifies and converts AC power into DC, an energy storage capacitor 9, an inverter circuit or switch circuit 10, and a welding transformer 11. The general thing consisting of may be sufficient.

  Here, before specifically explaining the resistance welding method according to the present invention, the formation of the protrusion P having the through hole H by the through hole / projection forming jig, which is the main feature of the present invention, will be described. 2 and FIG. The through hole / projection forming jig 21 does not rotate like a punch when the metal plate 1A of the first workpiece 1 has a thickness and material that can be pierced relatively easily. It's just something that moves up and down. The drive mechanism is not shown. The through-hole / projection portion forming jig 21 includes a perforated portion 22, a tapered portion 23 extending from the perforated portion 22 at a predetermined angle such as a conical shape or a pyramid shape, and a main body portion 24. The perforated portion 22 determines the size of the through-hole H drilled in the first workpiece 1, that is, the size of an annular surface that acts as a minute ring-shaped projection described later. Accordingly, the perforated portion 22 has a diameter d1 corresponding to the diameter of a through-hole H that acts as a micro-ring projection, which will be described later, and is determined from the thickness of the first work piece 1, for example, the work piece 1 The length L1 is about the same as the thickness or about several mm. From the viewpoint of life, the perforated portion 22 is preferably about the same as or slightly longer than the thickness of the work piece 1. The tip portion extending from the length L1 portion of the perforated portion 22 is tapered at an angle θ1 that is easy to perforate and is not easily worn out. This angle θ1 is preferably in the range of 80 to 100 degrees.

  In this embodiment, since the through hole / projection portion forming jig 21 does not rotate, the entire cross section of the through hole / projection portion forming jig 21 as well as the perforated portion 22 may have any shape such as a circular shape or a square shape. I do not care. The tapered portion 23 extends from the perforated portion 22 at an angle θ2, and preferably has a length L2 that is larger than the thickness of the workpiece 1 to be welded. The angle θ2 of the tapered portion 23 is an angle determined with reference to an angle at which a normal projection can be formed, and the angle θ2 is smaller than that of the conventional case when compared with workpieces having the same thickness and material. The range of this angle θ2 is 40 to 80 degrees, but from the viewpoint of obtaining good welding results such as small welding marks or high welding strength, it is preferably 50 to 70 degrees and should be smaller than the angle θ1. desired. The main body 24 has a diameter d2, is fixed to a vertical driving / pressurizing mechanism (not shown), and moves up and down with a pressing force with a through-hole / projection forming jig 21.

  With reference to FIG. 3, a method of forming the protrusion P having the through hole H in the center of the first workpiece 1 by using the aforementioned through hole / projection forming jig 21 will be described. The first workpiece 1 including the metal plate 1A and the electrical insulating film 1B formed on one surface thereof is placed on the support base 31 for drilling with the electrical insulating film 1B facing down. To do. The drilling support base 31 has a recess 32 at a location corresponding to the drilling portion 22 of the through hole / projection forming jig 21, and is a flat surface except for the portion where the recess 32 is formed. Yes. The recess 32 has a depth larger than the length of the perforated portion 22 and a diameter that does not get in the way when the protrusion P is formed.

  Accordingly, as shown in FIG. 3B, the through hole / projection forming jig 21 descends from above the metal plate 1A of the first work piece 1, and the punching portion 22 is formed by a pressurizing mechanism (not shown). When a predetermined pressure is applied to the tapered tip, a through-hole H is drilled in the first workpiece 1, the electrical insulating film 1B is broken at the most distal surface Ps of the projection P, and the through-hole / projection When the forming jig 21 is lowered and the taper portion 23 is pressed by the metal plate 1A of the first workpiece 1, the upper portion of the drawing is recessed according to the taper portion 23, and an enlarged view is shown in FIG. Thus, while forming the tapered surface T with the through hole H as the center, the surface on the side covered with the electrical insulating film 1B protrudes at the same time to form the protrusion P. When the projection P is formed, the through-hole / projection formation jig 21 is moved upward in FIG. Since the protruding portion P is formed in a state where the perforated portion 22 is inserted through the through hole H, the protruding portion P is formed with a good balance around the through hole H. The foremost surface Ps of the protrusion P is a thin annular surface having an inner diameter that is the diameter of the through hole H substantially equal to the diameter of the perforated portion 22, and the foremost surface Ps is not covered with the electrical insulating film 1B. Since the metal is exposed, it acts as a small annular projection during welding described later.

  Returning to FIG. 1, this resistance welding method will be described. The energy storage capacitor 9 is charged with the power of the AC power supply 7 when a switch element (not shown) included in the rectifier circuit 8 is turned on. Since the inverter circuit or switch circuit 10 is turned on after the charging voltage of the energy storage capacitor 9 reaches the set value, the energy charged in the energy storage capacitor 9 is changed to the inverter circuit or switch circuit 10 and welding. It is discharged in a short time between the first welding electrode 4 and the second welding electrode 5 through the transformer 11. The pulse current that flows along with the discharge of this energy is between the first and second workpieces 1 and 2, the most advanced surface that is a small annular conductive surface of any shape in the protrusion P shown in FIG. Concentrates on Ps. That is, since the cutting edge surface Ps that is the small annular conductive surface acts as a ring-shaped projection, the entire cutting edge surface Ps is welded during welding, although the contact area of the cutting edge surface Ps that is the small annular conductive surface is small. First, since it is melted, it is possible to increase the welding strength and to improve the welding quality, for example, the welding trace can be reduced. Due to this concentrated welding current, the entire projection P and the first and second workpieces 1 and 2 in the vicinity of the projection P are melted and mixed to form a nugget. At this time, the protrusion P and the electrical insulating film in the vicinity of the protrusion P are dissipated by heat. In the second work piece 2, no current flows through the mounting table 3. In the second work piece 2, the abutting portion that contacts the foremost surface Ps of the projection P of the first work piece 1 and the second work piece 2 are arranged. The metal plate 2 </ b> A flows along a plane between the contact point with the welding electrode 5 (indirect method).

  That is, in the first embodiment, the through-hole H is formed from above the metal plate 1A in the first workpiece 1 by simply applying a predetermined pressure or more to the through-hole / projection forming jig 21 prior to welding. The metal plate 1A is protruded on the electric insulating film 1B side by forming a projection P by piercing and further applying pressure, thereby easily and satisfactorily resistance-welding the electrically insulated metal plate. it can. In the resistance welding according to the first embodiment, a special position detection mechanism, a positioning mechanism, and the like are not necessary, and a welding result with excellent welding strength can be obtained with an existing general resistance welding apparatus.

[Embodiment 2]
The resistance welding method and apparatus according to the second embodiment is particularly suitable when the thickness of the first workpiece to be coated with an electrical insulating film on one side is thick and the through-hole is difficult or unclear with only the applied pressure. Is suitable. In the first embodiment, the through-hole / projection forming jig 21 shown in FIG. 2 performs only a reciprocating motion in a straight line, but in this second embodiment, the first rotational motion is performed, and then the rotational motion is stopped. The main feature is that it performs a reciprocating motion in a straight line later. A resistance welding method and apparatus and a workpiece to be welded according to the second embodiment will be described with reference to FIGS. 1 to 3.

  In the through hole / projection part forming jig 21 used in the second embodiment, the perforated part 22 is different from the through hole / projection part forming jig 21 used in the first embodiment. The perforated portion 22 has a structure in which a spiral groove (not shown) similar to that of a general drilling drill as commercially available is formed, and the perforated portion 22 rotates at a high speed. Therefore, it is possible to easily perforate with a relatively light pressure. Accordingly, in the second embodiment, the through hole / projection forming jig 21 having such a perforated portion 22 is rotated while being applied with a relatively light pressurizing force, and is first lowered by the perforated portion 22 serving as a drill. A through hole H is made in the metal plate 1A of the work piece 1 to be welded. As soon as the through-hole H is clear, the rotation of the through-hole / projection portion forming jig 21 is stopped, and at the same time, the pressure is increased to a predetermined value and lowered, and the taper of the through-hole / projection portion forming jig 21 is reduced. While the metal plate 1A is recessed by the portion 23 to form a tapered surface T having the through hole H at the center, the protruding portion P is formed by projecting to the electric insulating film 1B side at the same time. When the projection P is formed, the through hole / projection formation jig 21 is moved upward in FIG. Although not shown in detail, in FIG. 3 (B), the upper portion of the recess 32 of the drilling support base 31 may be a tapered portion convenient for forming the protrusion P.

  Also in the second embodiment, the protrusion P is the metal plate 1A of the first workpiece 1, that is, the conductive surface is a small annular conductive surface of an arbitrary shape in the protrusion P, as shown in FIG. It is exposed at the tip surface Ps. Therefore, as shown in FIG. 1, when the electric insulating film 1B side of the first workpiece 1 is overlapped on the second workpiece 2, it is a small annular conductive surface of the first workpiece 1. The most advanced surface Ps comes into contact with the metal plate 2A of the second workpiece 2 and electrical conductivity is reliably ensured between the first and second workpieces 1 and 2. As described in the first embodiment, when energization is performed between the first welding electrode 4 and the second welding electrode 5, first, the welding current is the small annular conductive surface of the first workpiece 1. The flow is concentrated on the foremost surface Ps, and preferable resistance welding is performed. Also in the second embodiment, the most advanced surface Ps, which is a small annular conductive surface, works as a ring-shaped projection, and a high-quality resistance welding result such as a sufficiently small welding mark can be obtained.

[Embodiment 3]
In the resistance welding of the first and second embodiments, both the first work piece 1 and the second work piece 2 are provided with the electrical insulating film on one side, so the first work piece 1 is indirect. However, in the third embodiment, since the second workpiece 2 is a metal member that does not include an electric insulation film, projection welding is performed by a direct method. An example of this will be described with reference to FIG. 4, the same symbols as those used in FIGS. 1 to 3 indicate members having the same names.

  The first workpiece 1 is the same as the workpiece described in the first embodiment or the second embodiment, and an electrical insulating film 1B is formed on one surface of the metal plate 1A. Since the method of forming the through hole H and the protrusion P in the first work piece 1 is the same as the method described in the first embodiment or the second embodiment, the description is omitted, but the protrusion P is the same as described above. Protrudes toward the electric insulating film 1B. The second workpiece 2 that has not been electrically insulated is placed on the second welding electrode 5. Next, on the second workpiece 2, the first workpiece 1 having the through holes H and the projections P formed thereon is overlapped with the projections P facing down. Next, the first welding electrode 4 is lowered or the second welding electrode 5 is raised, and the surface including the projection P of the first workpiece 1 between the first and second welding electrodes 4 and 5. The region and the second workpiece 2 are sandwiched and pressurized with a predetermined pressure, and a current is passed between the first and second welding electrodes 4 and 5 from the welding power source 6 in the pressurized state.

  First, the current is concentrated on the metal plate 1A of the first work piece 1, that is, the leading surface Ps (see FIG. 3), which is a small annular conductive surface of an arbitrary shape in the projection P, and the welding current Flows in the thickness direction of the first and second workpieces 1 and 2 and projection resistance welding is performed. In the third embodiment, the second workpiece is not limited to a metal plate, and may be any shape such as a metal pipe, a metal rod, or a special shape. In the third embodiment, the electrically insulated mounting table 3 shown in FIG. 1 is unnecessary, and even if an electrical insulating film is formed on the first workpiece 1, a small ring having an arbitrary shape in the protrusion P is used. Since the most advanced surface Ps, which is a conductive surface, acts as a ring-shaped projection, favorable welding results such as improved welding strength and small welding marks can be obtained.

[Embodiment 4]
Embodiment 4 of the present invention will be described with reference to FIG. In FIG. 5, the same symbols as those used in FIGS. 1 to 4 indicate members having the same names. In the fourth embodiment, a predetermined pressing force is applied from the metal plate 1A side by a general projection forming jig (not shown) to form a protrusion P projecting toward the electrical insulating film 1B as shown in FIG. To do. The height of the protrusion P is not limited, but is about 1 to 2 mm, for example. Next, as shown in FIG. 5B, the tip portion of the protrusion P is removed by about 1/2 to 1/3 by a polishing mechanism (not shown). Thereby, a cutting edge surface Ps such as a circular shape or a square shape corresponding to the shape of the protrusion P is obtained, and the cutting edge surface Ps is a surface from which a part of the metal plate 1A is exposed. Therefore, when both the first and second workpieces 1 and 2 are subjected to electrical insulation treatment, projection welding can be performed by the indirect method as described in the first embodiment, and When the first workpiece 1 is electrically insulated and the second workpiece 2 is not insulated, the direct projection is performed in the same manner as described in the third embodiment. Welding can be performed. Since projection welding has already been described, description thereof is omitted.

  In the above embodiment, the example in which the electrical insulating film 1B is formed on one side of the metal plate 1A has been described. However, the electrical insulating film 1B may be formed on the entire one side of the metal plate 1A, or a part thereof. It may be formed. Even when the electric insulating film 1B is formed on a part of one surface of the metal plate 1A, the present invention is effective when it is desired to perform welding at a location where the electric insulating film 1B is formed. The electrical insulating film may be made of an organic material or an inorganic material, and may be a metal oxide film.

It is a figure for demonstrating the resistance welding which concerns on Embodiment 1 or Embodiment 2 of this invention. It is a figure which shows a part of jig | tool for through-hole / projection part formation used for the resistance welding method which concerns on Embodiment 1 or Embodiment 2 of this invention. It is a figure for demonstrating formation of the projection part in the part of resistance welding which concerns on Embodiment 1 or Embodiment 2 of this invention, especially the to-be-welded object which concerns on this invention. It is a figure for demonstrating the resistance welding which concerns on Embodiment 3 of this invention. It is a figure which shows an example of the projection part in the to-be-welded object for performing resistance welding which concerns on Embodiment 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st to-be-welded object 1A ... Metal plate of 1st to-be-welded object 1 1B ... Electrical insulating film of 1st to-be-welded object 1 ... 2nd to-be-welded object 2A ... Metal member 2B of second workpiece 2 ... Electrical insulating film of second workpiece 2 3 ... Mounting table 4 ... First welding electrode 5 ... Second Welding electrode 6 ... Power source for welding 7 ... AC power source 8 ... Rectifier circuit 9 ... Capacitor for energy storage 10 ... Inverter circuit or switch circuit 11 ... Transformer for welding 21 ... Penetration Hole / projection forming jig 22 .. Drilling portion 23... Taper portion 24... Body portion 31... Drilling support base 32. ... Projection Ps ... The most advanced surface of projection P H ... Through hole T ... Tapered surface

Claims (8)

One surface side of the first workpiece to be welded covered with the electrical insulating film is brought into contact with the conductive surface of the second workpiece, and the first workpiece to be welded is pressed between them. In a resistance welding method in which a welding current is energized and welded between a workpiece and the second workpiece,
A protrusion projecting toward the one surface covered with the electric insulating film of the first workpiece is provided, and the tip of the protrusion penetrates, so that the electric tip is The insulating coating is broken and the conductive surface is exposed.
When the conductive surface of the tip of the projection in the first workpiece is in contact with the conductive surface of the second weld, the first workpiece and the weld at the tip of the projection A resistance welding method, wherein electrical conductivity is ensured between the second workpiece and the workpiece. In claim 1,
The tip surface of the projection formed on the first workpiece is a small annular conductive surface having an arbitrary shape, and the projection acts as a ring-shaped projection. Method. In claim 1 or claim 2,
The inner surface of the through hole formed by penetrating the tip of the protrusion is a thin cylindrical surface extending from a tapered portion having a tapered surface narrowing in the direction of the protrusion. . In claim 3,
The resistance welding method, wherein an angle of the tapered surface is in a range of 40 to 80 degrees. One surface side of the first workpiece to be welded covered with the electrical insulating film is brought into contact with the conductive surface of the second workpiece, and the first workpiece to be welded is pressed between them. In a resistance welding method in which a welding current is energized and welded between a workpiece and the second workpiece,
A protrusion projecting toward the one surface covered with the electrical insulating film of the first workpiece, and removing the electrical insulating film at the distal end of the projecting In the part, the electrically insulating coating is broken and the conductive surface is exposed,
When the conductive surface of the tip of the projection in the first workpiece is in contact with the conductive surface of the second weld, the first workpiece and the weld at the tip of the projection A resistance welding method, wherein electrical conductivity is ensured between the second workpiece and the workpiece. The first welding electrode in contact with the first workpiece, the second welding electrode in contact with the second workpiece, the first welding electrode and the second welding electrode through the first welding electrode. A welding power source for passing a welding current between the workpiece to be welded and the second workpiece to be welded, and one surface side covered with an electrical insulating film of the first workpiece to be welded is A resistance to which the first welding object and the second welding object are welded by energizing the welding current in a state in which they are brought into contact with the conductive surfaces of the two welding objects and pressed between them. In welding equipment,
A through hole / projection forming jig comprising a perforated portion having a tip tapered at a predetermined angle and a tapered portion extending from the perforated portion in a conical or pyramidal shape at a predetermined angle,
Before performing resistance welding, the through hole / projection forming jig is used to open a through hole in the first workpiece to break the electrical insulating film side and to form a tapered surface centered on the through hole. And forming a protruding portion protruding toward the electrical insulating film side,
A resistance welding apparatus, wherein the protrusion is brought into contact with a conductive surface of the second workpiece to weld the first workpiece and the second workpiece. In the work piece in which one surface side is covered with an electrical insulating film,
A protrusion projecting toward the one surface covered with the electric insulating film is provided, and the tip of the protrusion penetrates, or the electric insulating film at the tip of the protrusion is removed. The welded object is characterized in that the electrically insulating coating is broken and the conductive surface is exposed at the tip. In claim 7,
The to-be-welded object is characterized in that the tip surface of the projection is a small annular conductive surface or a small conductive surface having an arbitrary shape.

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