KR100782365B1 - Device for resistance welding - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention provides a resistance welding apparatus for reducing the surge voltage generated immediately after turning off the switching element to secure the switching element. In this power supply assembly, a capacitor 12, a switching transistor 14, and a flywheel diode 20 are provided on one substrate 30, and thin film conductors 34, 38, and 42 formed on both surfaces of the substrate 30 are formed. The electrical connections are made between the parts. More specifically, the anode terminal 12a of the condenser 12 and the current input terminal (not shown) of the switching transistor 14 are electrically connected to each other through the thin film conductor 34 for the anode side of the upper surface 30a of the substrate. Is connected. The current output terminal 14S of the switching transistor 14 and the cathode terminal 20C of the flywheel diode 20 are electrically connected to each other via the thin film conductor 42 for the anode side at the lower surface 30b side of the substrate. The cathode terminal 12b of the capacitor 12 and the anode terminal (not shown) of the flywheel diode 20 are electrically connected to each other via the thin film conductor 38 for the cathode side conductive path on the upper surface 30a side of the substrate.

Description

Resistance welding device {Device for resistance welding}

1 is a partial cross-sectional front view showing the assembly structure of the main part of the resistance welding apparatus according to an embodiment of the present invention.

2 is a plan view showing a substrate upper surface side configuration (state in which the heat dissipation member is omitted) in the assembly according to the embodiment.

3 is a partial cross-sectional side view showing the installation and wiring structure around the switching transistor in the assembly according to the embodiment.

4 is a partial plan view showing a thin film conductor pattern for signal lines on a lower surface side of a substrate in the assembly according to the embodiment.

5 is a partial cross-sectional side view showing the installation and wiring structure around the flywheel diode in the assembly according to the embodiment.

6 is a circuit diagram showing the basic circuit configuration of the main part of the resistance welding apparatus according to the present invention.

Figure 7 is a perspective view showing the physical configuration of the main portion of the power supply portion formed in the conventional resistance welding apparatus.

<Explanation of symbols for main parts of drawing>

12 capacitor 14 switching transistor                 

16: upper electrode 18: lower electrode

20: flywheel diode 30: substrate

32, 40, 56: separator 34, 42: thin film conductor for anode side conductive path

36, 54: thin film conductor for control line 38: thin film conductor for cathode side conductive path

44, 46, 48, 50, 52, 60, 62, 64, 66 mounting hole

58: resistance 72, 74: heat radiation member

78: conductive plate

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance welding apparatus, and more particularly, to a resistance welding apparatus of a method in which electric power, which becomes welding energy, is accumulated in a capacitor and then supplied to a welded material through a switching element.

6 is a diagram showing the basic circuit configuration of the main part of such a resistance welding apparatus. The charging circuit 10 includes, for example, a single-phase full-wave rectifier circuit formed by bridge connection of a plurality of diodes, and is a single-phase AC power supply voltage Ea of commercial frequency through an insulated transformer (not shown) from an AC power line. ) Is input, and the DC voltage is output by performing a full wave rectifier on the input AC power voltage Ea. The capacitor 12 is charged to a predetermined voltage value Ec in accordance with the output voltage of the charging circuit 10.

The positive terminal of the capacitor 12 is electrically connected to the first welding electrode 16 through a switching element, for example, a field effect transistor (FET) 14, and the negative terminal is connected to the second welding electrode 18. Electrically connected. In the energization method in which the switching transistor 14 is controlled on / off at a high frequency (for example, 1 kHz), the cathode terminal and the anode terminal are respectively set to a predetermined polarity between the first and second welding electrodes 16 and 18. And a flywheel diode 20 connected to the second welding electrodes 16 and 18.

At the time of welding energization, the 1st and 2nd welding electrodes 16 and 18 press-contact with the to-be-welded material W1 and W2 from both sides by the action of a pressurizing apparatus (not shown). Then, when the switching transistor 14 is turned ON by the control signal CS output from the control circuit (not shown), the capacitor 12 is discharged to the load (welding part) side, and the discharge current is the welding current ( As Iw, the welding electrodes 16 and 18 and the to-be-welded materials W1 and W2 flow. In the high frequency switching method, when the switching transistor 14 is turned off, the welding current Iw continues to flow in a closed circuit between the flywheel diode 20 and the load (welding part).

7 is a view showing the physical configuration of the main portion of the power supply portion formed in the conventional resistance welding apparatus. Generally, as the capacitor | condenser 12, the cylindrical electrolytic capacitor in which the pair of rod-shaped terminals 12a and 12b protrudes from one end surface is used. In the conventional apparatus, as shown in the drawing, three components of the capacitor 12, the switching transistor 14, and the diode 20 are electrically connected through the copper bars 100, 102, and 104.

In the conventional resistance welding apparatus as described above, a large surge voltage in the loop circuit L of the power supply section including the capacitor 12, the transistor 14, and the diode 20 immediately after the switching transistor 14 is turned off ( surge voltage) is generated, and the switching transistor 14 may be destroyed by the surge voltage.

Such a surge voltage depends on the total length or loop distance of the loop circuit L, and the larger the loop distance, the larger the surge voltage. By the way, since the conventional apparatus uses the copper rod 100, 102, 104 for the connection conductor of the loop circuit L, it was difficult to shorten a loop distance. For this reason, as a countermeasure against surge voltage, the structure which attaches the protection circuit (not shown), such as a snubber circuit, to the transistor 14 is employ | adopted, and the apparatus cost was high. In addition, as the overall length of the loop circuit L is large, it is difficult to miniaturize the power supply unit.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide a resistance welding device in which the surge voltage generated immediately after turning off the switching element is reduced to ensure the safety of the switching element.

Another object of the present invention is to provide a resistance welding apparatus which does not require a protection circuit for withstanding a surge voltage in a switching element.

It is still another object of the present invention to provide a resistance welding apparatus that realizes light weight and small size of the power supply unit.

In order to achieve the above object, the resistance welding device of the present invention is the first and second welding electrodes of the capacitor for accumulating and then discharging the electric power for resistance welding once for the first and second welding electrodes in pressure contact with the material to be welded for welding energization. A terminal is electrically connected to the first welding electrode through a switching element, and at the same time, a second terminal of the capacitor is electrically connected to the second welding electrode, and has a predetermined polarity between the first and second welding electrodes. A resistance welding device formed by electrically connecting a flywheel diode, wherein the capacitor, the switching element, and the flywheel diode are disposed on a substrate, and the capacitor, the switching element, and the flywheel are provided through a plurality of thin film conductors formed on both surfaces of the substrate. The diode was electrically connected.

In the resistance welding apparatus of the present invention, a capacitor, a switching element, and a flywheel diode are densely integrated on both sides or one side of the substrate, and electrically connected between the portions through a plurality of thin film conductors formed on both sides of the substrate. A compact assembly structure can be realized, and at the same time, the overall length or distance of the loop circuit in the power supply section including these three components or elements can be made as short as possible. Therefore, the surge voltage generated in the loop circuit immediately after switching the switching element from on to off is very small, and it is possible to prevent the destruction of the switching element even without attaching a special protection circuit.

A resistance welding device according to one preferred embodiment of the present invention includes a first terminal of a capacitor that accumulates and discharges electric power for resistance welding once for the first and second welding electrodes that are in pressure contact with the material to be welded for welding conduction. The second terminal of the condenser is electrically connected to the second welding electrode at the same time as the electrical connection to the first welding electrode through a switching element, and the fly has a predetermined polarity between the first and second welding electrodes. A resistance welding device formed by electrically connecting a wheel diode, the first and second thin film conductors being electrically isolated from each other on a first surface of a substrate made of an insulating member, respectively, and fixedly formed. Fixedly forming a third thin film conductor electrically isolated from any of the first and second thin film conductors, and placing the capacitor on the second surface side of the substrate, Connecting the first and second terminals of the capacitor to the first and second thin film conductors on the first side of the substrate, respectively, and placing the switching element on the first and second side of the substrate, the switching element A terminal of the current input side of the substrate connected to the first thin film conductor on the first surface side of the substrate, a terminal of the current output side of the substrate connected to the third thin film conductor on the second surface side of the substrate, and A cathode terminal of the flywheel diode connected to the third thin film conductor on the second side of the substrate and an anode terminal connected to the second thin film conductor on the first side of the substrate; The third and second thin film conductors are electrically connected to the first and second welding electrodes, respectively.

In the resistance welding device of the present invention, when the switching element is continuously turned on as a kind of variable resistor, the flywheel diode can be omitted in the above configuration.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of this invention is described with reference to FIGS.

1-5 show the assembly structure of the principal part of the resistance welding apparatus which is one Embodiment of this invention. The resistance welding apparatus of this embodiment also has a circuit configuration as shown in FIG. 6, and the assembly shown in FIG. 1 includes a capacitor 12, a switching transistor 14, and a flywheel diode 20 of the circuit shown in FIG. Doing.

In this assembly, for example, the substrate 30 made of an insulating member such as glass epoxy is used as the main body, and the capacitor 12 is provided on one side (lower side in FIG. 1) of the substrate 30, and the other side (upper side in FIG. 1). ), A switching transistor 14 and a flywheel diode 20 are provided.

On both surfaces of the substrate 30, a conductive thin film conductor made of, for example, copper foil is fixedly formed by plating or the like. As shown in FIG. 2, a thin film conductor 34 for an anode side and a thin film conductor 36 for a control line are placed on the upper side (first surface) 30a of the substrate 30 with the separator 32 at the center thereof on the left side. Are each formed in a wide pattern, and on the right side, the thin film conductor 38 for the cathode side conductive path is formed in a wide (almost one side) pattern. In the left area, a thin film conductor 34 for anode side conductive material is located inward (center separator side) with the separator 40 near the left end, and a control line thin film conductor 36 is located outside (left side). .

As described later, the thin film conductor 34 for the anode-side conductive path is a conductive path between the anode-side terminal 12a of the capacitor 12 and the current input side terminal (eg, drain terminal) 14D of the switching transistor 14. Configure The thin film conductor 36 for the control line is for transmitting the control signal CS (Fig. 6) output from the control circuit (not shown) to the control terminal (for example, the gate terminal) 14G of the switching transistor 14. Construct a conductive path. The thin film conductor 38 for the cathode side conductive path constitutes a conductive path between the cathode terminal 12b of the capacitor 12 and the anode terminal 20A of the flywheel diode 20. An insulating film (not shown) is coated on the surface of each thin film conductor 34, 36, 38.

The capacitor 12, the switching transistor 14 and the flywheel diode 20 may be one each, but as shown in FIG. 2, a plurality of capacitors 12 may be formed in parallel connection. 2 is a figure which shows the structure on the board | substrate 30 in the state which abbreviate | omitted the heat sink 72 and 74 (FIG. 1) mentioned later in a top view.

On the lower surface (second surface) 30b of the substrate 30, a detailed pattern diagram (top view) is omitted, but at least the substrate region (area) in which the capacitor 12, the switching transistor 14, and the flywheel diode 20 are arranged. ), A thin film conductor 42 for anode side conductive paths is formed in a predetermined pattern. As described later, the thin film conductor 42 constitutes a conductive path between the current output side terminal (for example, source terminal) 14S of the switching transistor 14 and the cathode terminal 20C of the flywheel diode 20. An insulating film (not shown) is also coated on the surface of the thin film conductor 42.

Each terminal of the condenser 12, the switching transistor 14, and the flywheel diode 20 on the substrate 30 is inserted into a corresponding installation hole (through hole), respectively, and the upper surface of the substrate 30a or the lower surface of the substrate 30b. It is connected to the thin film conductor corresponding to each side by soldering, for example.

More specifically, both terminals 12a and 12b of the condenser 12 are inserted into the mounting holes 44 and 46 of the substrate 30, respectively, and the anode side terminal 12a is the anode side from the substrate upper surface 30a side. It is connected to the thin-film conductor 34 for conductive paths (FIG. 1), and the negative electrode side terminal 12b is connected to the thin-film conductor 38 for the negative-side conductive path on the upper surface 30a side of a board | substrate (FIG. 1).                     

The current input side terminal 14D and the current output side terminal 14S of the switching transistor 14 are inserted into the mounting holes 48 and 50 of the substrate 30, respectively, and the current input side terminal 14D is provided on the substrate upper surface 30a side. Is connected to the anode-side conductive path thin film conductor 34 (FIG. 3), and the current output side terminal 14S is connected to the anode-side conductive path thin film conductor 42 at the substrate lower surface 30b side (FIG. 1, 3). The control terminal 14G of the switching transistor 14 is inserted into the mounting hole 52 of the substrate 30 and is connected to the control line thin film conductor 54 on the lower surface 30b side of the substrate (FIG. 3). . As shown in Fig. 4, on the bottom surface 30b side of the substrate, the control line thin film conductor 54 is formed on the bottom surface of the substrate in an island-shaped pattern separated from the anode side conductive thin film conductor 42 through the separator 56 ( 30b). An insulating film (not shown) is also coated on the surface of the thin film conductor 54.

In this embodiment, a resistor 58 for passing the control signal CS on the upper surface 30a of the substrate is provided. The signal input terminal 58J of the resistor 58 is inserted into the installation hole 60 of the substrate 30 and is connected to the thin film conductor 36 on the upper surface 30a side of the substrate (Fig. 3). The signal output side terminal 58K of the resistor 58 is inserted into the mounting hole 62 of the substrate 30, and is connected to the thin film conductor 54 on the lower surface 30b side of the substrate (Figs. 1 and 3).

The cathode terminal 20C and the anode terminal 20A of the flywheel diode 20 are inserted into the mounting holes 64 and 66 of the substrate 30, respectively, and the cathode terminal 20C is the anode side from the lower surface of the substrate 30b. 1 and 5 are connected to the conductive path thin film conductor 42, and the anode terminal 20A is connected to the thin film conductor 38 for the cathode side conductive path on the upper surface 30a side of the substrate (FIG. 5).

Due to the mounting on the substrate 30 as described above, each component 12, 14, 20 is electrically connected as follows. The anode side terminal 12a of the capacitor 12 and the current input side terminal 14D of the switching transistor 14 are electrically connected to each other via the thin film conductor 34 for the anode side conductive path on the upper surface 30a side of the substrate. The current output terminal 14S of the switching transistor 14 and the cathode terminal 20C of the flywheel diode 20 are electrically connected to each other via the thin film conductor 42 for the anode side at the lower surface 30b side of the substrate. The cathode terminal 12b of the capacitor 12 and the anode terminal 20A of the flywheel diode 20 are electrically connected to each other via the thin film conductor 38 for the cathode side conductive path on the upper surface 30a side of the substrate.

As shown in Fig. 2, the substrate 30 is provided with an external conductor terminal mounting hole (through hole) 68 in the region of the thin film conductor 34 for the anode side conductive path. The inner wall and the periphery of the outer conductor terminal mounting hole 68 are covered with the thin film conductor 70, and are electrically or continuously connected to the thin film conductor 34 on the upper surface 30a of the substrate. One end or terminal (not shown) of the conductor communicating with the anode side output terminal of the charging circuit 10 (FIG. 6) is mounted in the external conductor terminal mounting hole 68, whereby the anode side output terminal of the charging circuit 10 The terminal 12a of the capacitor 12 and the current input terminal 14D of the switching transistor 14 are electrically connected to each other.

In this embodiment, as shown in FIG. 1, heat dissipation members 72 and 74 having high thermal conductivity for absorbing or dissipating heat generated from the switching transistor 14 and the flywheel diode 20 are provided on the substrate 30. have.

The heat dissipation member 72 is made of, for example, a heat sink having a cross-section 'CO' shape, and is fixed to the substrate 30 with a bolt (not shown). A conductive and thermally conductive metal plate portion 14M which is electrically shorted with the current input side terminal 14D is formed on the package back side of the switching transistor 14. The switching transistor 14 is fixed with a fixing member (not shown) and thermally coupled to the heat dissipation member 72 so that the metal plate portion 14M is brought into close contact with the outer wall surface of the heat dissipation member 72.

The heat dissipation member 72 is made of a material having high conductivity as well as thermal conductivity, for example, aluminum, and locally exposes the thin film conductor 34 on the upper surface 30a of the substrate at the bottom of the heat dissipation member 72, A configuration in which the 34 is electrically connected to the metal plate portion 14M or the current input side terminal 14D of the switching transistor 14 through the heat dissipation member 72 is also possible. Alternatively, the heat dissipation member 72 may be provided with an electrical terminal or a connecting portion that replaces the external conductor terminal mounting hole 68.

The heat dissipation member 74 is also made of, for example, a heat sink having a cross-section 'CO' shape, and is fixed to the substrate 30 with a bolt (not shown). The conductive and thermally conductive metal plate portion 20M electrically shorted with the cathode terminal 14D is also formed on the back surface of the flywheel diode 20. The flywheel diode 20 is fixed to the heat dissipation member 74 to be in close contact with the outer wall surface of the heat dissipation member 74 by the metal plate 20M, and is fixed with a fixing member (not shown) and thermally coupled.

The heat dissipation member 74 of the illustrated configuration is made of a material having high conductivity as well as thermal conductivity, for example, aluminum, and has an external conductor terminal connection portion 74a at one end. One end or terminal (not shown) of the conductor communicating with the upper electrode 16 (Fig. 6) is connected to this external terminal connecting portion 74a.                     

Under the bottom of the heat radiating member 74, a plate-shaped conductive member 78 made of, for example, a copper plate is inserted through the insulating plate 76. The conductive member 78 is electrically connected to the thin film conductor 38 for the cathode side conductive path on the upper surface 30a of the substrate, and has an external conductor terminal connection portion 78a at one end thereof. One end or terminal (not shown) of the conductor in communication with the lower electrode 18 (FIG. 6) and one end or terminal (not shown) of the conductor in communication with the negative electrode output terminal of the charging circuit 10 (FIG. 6). By being connected to the external terminal connecting portion 78a, the negative electrode output terminal of the charging circuit 10, the negative electrode terminal 12b of the condenser 12, the anode terminal 20A of the flywheel diode 20 and the lower electrode 18 These are electrically interconnected or common.

In the power supply assembly having the above configuration according to this embodiment, one substrate 30 is sandwiched and the capacitor 12, the switching transistor 14, and the flywheel diode 20 are integrated at high density on both sides (both sides thereof), and the substrate 30 Since the circuits are electrically connected between the respective portions through the thin film conductors 34, 38, and 42 formed on both sides of the circuit, the loop circuit L including the capacitor 12, the switching transistor 14, and the flywheel diode 20 (Fig. 6), the total length or distance is much shorter than that of the conventional apparatus (Fig. 7). For this reason, the surge voltage generated in the loop circuit L immediately after switching the switching transistor 14 from the on state to the off state is very small, and the switching transistor 14 is not required even if a protection circuit such as a snubber circuit is not provided. To keep it safe.

As described above, the capacitor 12, the switching transistor 14, and the flywheel diode 20 are integrated at high density on both sides of one substrate 30, and are electrically connected through a thin film conductor on the substrate. Assembly, the power supply can be made compact. This advantage is more remarkable when a plurality of these parts 12, 14, and 20 are each formed in parallel connection (the more the number of parts).

In the above embodiment, the switching transistor 14 and the flywheel diode 20 are disposed on the side opposite to the capacitor 12 (substrate upper surface 30a side) with respect to the substrate 30, but on the same side (substrate lower surface 30b side). Arrangement is also possible.

In the assembly of the above embodiment, a configuration corresponding to the conductive member 78 may be formed on the anode-side conductive path thin film conductor 34 or the control signal thin film conductor 36, or the external conductor terminal mounting hole ( The structure corresponding to 68) may be formed in the region of the thin film conductor 38 for the cathode side conductive path or the thin film conductor 36 for the control signal.

In the above embodiment, the flywheel diode 20 is formed in connection with the energization method of turning on and off the switching transistor 14 at a high frequency. However, the present invention is also applicable to an energization method that continuously turns on the switching transistor 14 as a kind of variable resistor, and it is possible to omit the flywheel diode 20 in such an energization method.

As described above, according to the resistance welding apparatus of the present invention, since the surge voltage generated immediately after the switching element is turned off can be reduced, it is necessary to ensure the safety of the switching element without forming a protection circuit to withstand the surge voltage. It is also possible to easily realize the miniaturization of the power supply unit.

Claims (14)

For the first and second welding electrodes that are in pressure contact with the welded material for welding energization, the first terminal of the capacitor, which accumulates and discharges the resistance welding power once, is electrically connected to the first welding electrode through a switching element. A resistance welding device in which a second terminal of the capacitor is electrically connected to the second welding electrode, and a flywheel diode is electrically connected between the first and second welding electrodes with a predetermined polarity. Resistance welding, wherein the capacitor, the switching element and the flywheel diode are disposed on a substrate, and the capacitor, the switching element and the flywheel diode are electrically connected through a plurality of thin film conductors formed on both sides of the substrate. Device. For the first and second welding electrodes that are in pressure contact with the welded material for welding energization, the first terminal of the capacitor, which accumulates and discharges the resistance welding power once, is electrically connected to the first welding electrode through a switching element. A resistance welding device in which a second terminal of the capacitor is electrically connected to the second welding electrode, and a flywheel diode is electrically connected between the first and second welding electrodes with a predetermined polarity. Fixing the first and second thin film conductors electrically separated from each other on the first surface of the substrate made of an insulating member, respectively, and electrically connecting the first and second thin film conductors to any of the first and second thin film conductors on the second surface of the substrate. Fixation of the separated third thin film conductor, The capacitor is arranged on the second surface side of the substrate, and the first and second terminals of the capacitor are connected to the first and second thin film conductors on the first surface side of the substrate, respectively. The switching element is disposed on the first and second surface sides of the substrate, and the current input terminal of the switching element is connected to the first thin film conductor on the first surface side of the substrate, and the current output terminal is connected to the first surface of the substrate. Connected to the third thin film conductor from two surface sides, The flywheel diode is disposed on the first or second surface side of the substrate, and the cathode terminal of the flywheel diode is connected to the third thin film conductor on the second surface side of the substrate and an anode terminal is connected to the first surface side of the substrate. Is connected to the second thin film conductor, And the third and second thin film conductors are electrically connected to the first and second welding electrodes, respectively. For the first and second welding electrodes that are in pressure contact with the welded material for welding energization, the first terminal of the capacitor, which accumulates and discharges the resistance welding power once, is electrically connected to the first welding electrode through a switching element. In the resistance welding device in which the second terminal of the capacitor is electrically connected to the second welding electrode while being connected. And a capacitor and the switching element disposed on a substrate, and electrically connecting the capacitor and the switching element through a plurality of thin film conductors formed on both sides of the substrate. For the first and second welding electrodes that are in pressure contact with the welded material for welding conduction, the first terminal of the capacitor that accumulates and discharges the resistance welding power once and is electrically connected to the first welding electrode through a switching element. In the resistance welding device in which the second terminal of the capacitor is electrically connected to the second welding electrode while being connected. Fixing the first and second thin film conductors electrically separated from each other on a first surface of the substrate made of an insulating member, and electrically connecting the first and second thin film conductors to either of the first and second thin film conductors on the second surface of the substrate. Fixation of the separated third thin film conductor, The capacitor is arranged on the second surface side of the substrate, and the first and second terminals of the capacitor are connected to the first and second thin film conductors on the first surface side of the substrate, respectively. The switching element is disposed on the first and second surface sides of the substrate, and the current input terminal of the switching element is connected to the first thin film conductor on the first surface side of the substrate, and the current output terminal is connected to the first thin film conductor. Connected to the third thin film conductor from two surface sides, And the third and second thin film conductors are electrically connected to the first and second welding electrodes, respectively. The switching device according to any one of claims 1 to 4, wherein the switching element is formed of a transistor, and any of the first, second and third thin film conductors is formed on the first and / or second surfaces of the substrate. And the fourth thin film conductor is electrically separated from each other, and the control terminal of the transistor is electrically connected to the fourth thin film conductor. The resistance welding device according to claim 1 or 2, wherein a through hole is formed in said substrate to pass each terminal of said flywheel diode. The resistance welding device according to any one of claims 1 to 4, wherein a through hole is formed in said substrate to pass each terminal of said capacitor and said switching element. The resistance welding device according to any one of claims 1 to 4, wherein a first heat dissipation member thermally coupled to the switching element is formed on the first and / or second surfaces of the substrate. 9. The resistance welding apparatus according to claim 8, wherein the first heat dissipation member is made of a conductive member and is electrically connected to any one of the first, second, and third thin film conductors. The resistance welding device according to claim 1 or 2, wherein a second heat dissipation member thermally coupled to the flywheel diode is formed on the first and / or second surfaces of the substrate. The resistance welding device according to claim 10, wherein the second heat dissipation member is made of a conductive member and electrically connected to any one of the first, second, and third thin film conductors. The resistance welding device according to any one of claims 1 to 4, wherein a plurality of the capacitors are formed in parallel connection. The resistance welding device according to any one of claims 1 to 4, wherein a plurality of the switching elements are formed in parallel connection. The resistance welding device according to claim 1 or 2, wherein a plurality of said flywheel diodes are formed in parallel connection.

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