JP2012106254A - Resistance welding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resistance welding apparatus that reliably prevents a short circuit from occurring.SOLUTION: The resistance welding apparatus includes: a welding gun 30 for applying a welding current while applying a pressure to workpieces W, W; a welding transformer 20 that is integrally formed with the welding gun 30 and applies a welding current to the welding gun 30; a welding timer 10 for feeding electrical power to the welding transformer 20; a feeder cable 50 for connecting the welding transformer 20 with the welding timer 10 so that electrical power is fed from the welding timer 10 to the welding transformer 20; and an electrical leakage breaker 40 for monitoring an electrical leakage in the feeder cable 50. The feeder cable 50 includes: power lines 51, 52 that include conductors 51a, 52a and insulators 51b, 52b for coating the conductors 51a, 52a, are disposed in the feeder cable 50, while spacing predetermined intervals therebetween and feed electrical power to the welding transformer 20; and first combination conductors 53, 54 disposed between the power lines 51, 52 and connected to ground.

Description

  The present invention relates to a technique of a resistance welding apparatus including a power supply cable for supplying electric power to a welding transformer formed integrally with a welding gun.

  2. Description of the Related Art Conventionally, in automobile body production or the like, resistance welding work is performed in which a welding current is applied while applying pressure to a plurality of workpieces to join the workpieces. As an apparatus for performing such resistance welding work, for example, there is a resistance welding apparatus 101 as shown in FIG.

The resistance welding apparatus 101 is provided with a welding transformer 120 between a welding timer 110 and a welding gun 130, and the welding timer 110 and the welding transformer 120 are connected by a primary cable 160, and the welding transformer 120 and the welding gun 130 are connected to each other. They are connected with a secondary cable 150.
In such a resistance welding apparatus 101, a high voltage is applied to the primary cable 160 and transformed to a low voltage by the welding transformer 120. And since a welding current is sent to the welding gun 130 via the secondary cable 150, much energy is consumed in the secondary cable 150.

As a resistance welding apparatus for efficiently consuming energy, a portable resistance welding apparatus in which a welding transformer and a welding gun are integrally formed is known (for example, Non-Patent Document 1).
In such a portable resistance welding apparatus, the welding transformer and the welding timer are connected by a power supply cable, and a high voltage is applied to the power supply cable to perform resistance welding work. According to this, since resistance welding work can be performed without using a secondary cable, energy can be consumed efficiently.

Here, the power supply cable 250 includes, for example, two power lines 251 and 252 and a ground line 255 as shown in FIG. Each of the power lines 251 and 252 is connected to the output terminal of the welding timer and the primary terminal of the welding transformer, and supplies power to the welding gun. Both ends of the ground wire 255 are connected to the ground terminals of the welding gun and the welding timer.
The power supply cable 250 is configured as a single cable in which a paper tape 258 is wound in a state in which the wires 251, 252, 255, and the inclusions 257 such as yarns are twisted together and covered with an insulating sheath 259.

Such a power feeding cable 250 moves as the welding gun moves. Therefore, in a portable resistance welding apparatus used for a high usage rate application (for example, installed in a production line), as shown in FIG. 10, a part of each insulator 251b, 252b, 255b (insulation of the power line 252) The symbol P10) shown in the body 252b may deteriorate.
In such a case, the power line 252 comes into contact with the adjacent electric wire, that is, the conductor 252a of the power line 252 is replaced with another conductive member (the conductor 251a of the power line 251 or the conductor 255a of the ground line 255). Will come in contact with. In particular, since a high voltage is applied to the power supply cable 250, the portable resistance welding apparatus may be damaged if the conductors 251a and 252a of the power lines 251 and 252 contact each other and are short-circuited. .

  As a technique for solving such a problem, there is a welding cable abnormality detection device disclosed in Patent Document 1. The welding cable abnormality detection device disclosed in Patent Document 1 covers an inner shield body on the outer circumferences of two power lines and a ground line. Each power supply line, ground line, and each internal shield body are connected to a plurality of abnormality detection circuits, respectively. When the insulator covering each power supply line deteriorates, each power supply line and each internal shield body come into contact with each other, and an abnormality signal is output through the abnormality detection path corresponding to the contacted power supply line and internal shield line.

The welding cable abnormality detection device disclosed in Patent Document 1 is for predicting damage inside the cable, and is not for preventing the occurrence of an actual short circuit. Therefore, when the resistance welding operation is continued without noticing the abnormality detection signal, the deterioration of the insulator further proceeds and there is a possibility of short circuit.
In addition, since it is necessary to provide a plurality of abnormality detection circuits, when the welding cable abnormality detection device is applied to the portable resistance welding device, the structure becomes complicated and the cost increases.

Japanese Utility Model Publication No. 6-45532

Welding technology January 2010 issue, cover explanation

  The present invention has been made in view of the above situation, and provides a resistance welding apparatus that can reliably prevent occurrence of a short circuit.

  2. The welding gun for passing a welding current while applying pressure to a workpiece, a welding transformer that is integrally formed with the welding gun and for passing the welding current to the welding gun, and supplying electric power to the welding transformer. A welding timer, a power feeding cable connecting the welding transformer and the welding timer so that power can be supplied from the welding timer to the welding transformer, and a leakage monitoring means for monitoring a leakage in the feeding cable The power supply cable has a conductor and an insulator covering the conductor, and is disposed in the power supply cable at a predetermined distance from each other, for supplying power to the welding transformer. Two power lines and a shielding member disposed between the power lines and grounded.

  According to a second aspect of the present invention, the shielding member covers at least one of the conductors of the power lines.

  According to a third aspect of the present invention, the power supply cable further includes a ground wire twisted together with the power lines and the shielding member.

  In Claim 4, two said earth lines are arrange | positioned so that the said each power line may be adjoined along the circumferential direction of the said electric power feeding cable, and the said shielding member may pass between each said power lines. The ground wires are integrally covered.

  In the present invention, when the conductor covered with the deteriorated insulator is exposed when the insulator of the power line is deteriorated, first, the conductor contacts the shielding member first, and the power supply to the welding timer is automatically cut off by the earth leakage breaker. There is an effect that the occurrence of a short circuit can be surely prevented.

Explanatory drawing which shows the whole structure of a resistance welding apparatus. Sectional drawing which shows the structure of an electric power feeding cable. Sectional drawing which shows the electric power feeding cable which does not coat | cover a 2nd braided conductor on an earth wire. Sectional drawing which shows the state in which the power line is breaking. Sectional drawing which shows the electric power feeding cable which arrange | positions a strip | belt-shaped 1st braided conductor. Sectional drawing which shows the electric power feeding cable which does not arrange | position a ground wire. (A) The figure which shows the electric power feeding cable which coat | covers a 1st braided conductor to each power line. (B) The figure which shows the electric power feeding cable which coat | covers a 1st braided conductor in any one of a power line. Sectional drawing which shows the electric power feeding cable which coat | covers two earth wires and each earth wire with one 1st braided conductor. Explanatory drawing which shows the whole structure of the conventional resistance welding apparatus. Sectional drawing which shows the structure of the conventional electric power feeding cable. Sectional drawing which shows the state which the power line of the conventional electric power feeding cable is going to break.

  Below, resistance welding apparatus 1 which is one embodiment of the resistance welding apparatus concerning the present invention is explained with reference to drawings.

The resistance welding apparatus 1 allows welding current to flow while applying pressure to a plurality of (two in FIG. 1) workpieces W and W supported in a state of being superimposed on the jig 2 in a predetermined posture. Work W and W are joined.
Examples of the workpieces W and W to be joined include a steel plate used for an automobile body.

  As shown in FIG. 1, the resistance welding apparatus 1 includes a welding timer 10, a welding transformer 20, a welding gun 30, an earth leakage breaker 40, a power feeding cable 50, and the like.

  The welding timer 10 is configured to be able to supply power from the welding turntable to the welding transformer 20 via a cable, a distribution board, and the like. The welding timer 10 sets the welding conditions (the magnitude of the welding current, the length of the welding time, the magnitude of the pressure on the workpiece W, etc.) based on the number of workpieces W to be joined, the thickness of the workpiece W, and the like. The welding transformer 20 and the welding gun 30 are controlled so as to perform resistance welding work under the set welding conditions.

  The welding transformer 20 includes a plurality of coils and the like, transforms the input voltage from the welding timer 10 by each coil and the like, and causes a welding current having a magnitude set by the welding timer 10 to flow to the welding gun 30.

  The welding gun 30 applies a welding current to each workpiece W · W while applying pressure to each workpiece W · W. The welding gun 30 includes two electrodes 31 and 31, a cylinder 32, and the like.

The electrodes 31 and 31 are arranged to face each other in the vertical direction in FIG.
When performing resistance welding work, an operator, a robot, or the like that performs resistance welding work holds the workpieces W / W between the electrodes 31 and 31. And a welding current is sent through each electrode 31 * 31.

The cylinder 32 is connected to the upper electrode 31 so that the upper electrode 31 in FIG. 1 can be moved in the vertical direction of the drawing in FIG.
When performing resistance welding work, an operator, a robot, or the like moves the upper electrode 31 downward by the cylinder 32 with the pressure set by the welding timer 10. Pressurize W.

  The welding transformer 20 and the welding gun 30 are integrally formed so as not to move relative to each other. In addition, the welding transformer 20 and the welding gun 30 are configured to be suspended through an I beam, a balancer, and the like and to be moved to a desired position.

  The earth leakage breaker 40 as the earth leakage monitoring means monitors the earth leakage in the resistance welding apparatus 1 (power feeding cable 50). The earth leakage breaker 40 is provided in a distribution board for supplying electric power to the welding timer 10. The leakage breaker 40 determines that the resistance welding apparatus 1 is leaking current when the difference between the current directed to the welding gun 30 and the current returned from the welding gun 30 is equal to or greater than a predetermined threshold. The power supply from the electric panel to the welding timer 10 is automatically cut off.

The power supply cable 50 is for supplying electric power from the welding timer 10 to the welding transformer 20, and one end portion is connected to the welding timer 10 and the other end portion is connected to the welding transformer 20. The feed cable 50 is set to a length dimension that allows the welding transformer 20 and the welding gun 30 to move within a certain range, and a midway portion thereof is suspended via an I-beam, a balancer, and the like.
As shown in FIG. 2, the power supply cable 50 includes two power lines 51 and 52, two first braided conductors 53 and 54, a ground wire 55, and a second braided conductor 56.

  Each power line 51 and 52 is for supplying electric power to the welding transformer 20. The power lines 51 and 52 have conductors 51a and 52a and insulators 51b and 52b, respectively.

  Both ends of each of the conductors 51a and 52a are connected to the output terminal of the welding timer 10 and the primary side terminal of the welding transformer 20, respectively. Each of the conductors 51a and 52a is made of, for example, copper.

  The insulators 51b and 52b cover the conductors 51a and 52a, respectively, and insulate the conductors 51a and 52a from other conductive members of the power supply cable 50. The insulators 51b and 52b are made of rubber or the like, for example.

  The first braided conductors 53 and 54 as shielding members cover the power lines 51 and 52, respectively. Each of the first braided conductors 53 and 54 is unraveled so as to be a single line by being loosened at both ends thereof. Then, the welding timer 10 and the welding transformer 20 are connected to the ground terminals. That is, the first braided conductors 53 and 54 are grounded. The first braided conductors 53 and 54 have paper tapes 53a and 54a wound around the outer sides thereof.

  As described above, in the power supply cable 50, gaps are formed between the power lines 51 and 52 so that the first braided conductors 53 and 54 can be covered, and the first braided conductors 53 are formed in the gaps. -54 is arranged.

  In the present embodiment, the power lines 51 and 52 cover the first braided conductors 53 and 54, respectively, but the present invention is not limited to this. That is, the shielding member that covers the power lines 51 and 52 may be, for example, an aluminum tape.

  The ground wire 55 has a conductor 55a and an insulator 55b covering the conductor 55a, and both ends of the conductor 55a are connected to the ground terminals of the welding timer 10 and the welding transformer 20 together with the first braided conductors 53 and 54.

  The second braided conductor 56 is configured in the same manner as the first braided conductor 53 except that it covers the ground wire 55, and a paper tape 56a is wound around the outer side thereof.

  Note that the second braided conductor 56 is not necessarily arranged in the power supply cable 50 (see FIG. 3).

  The power supply cable 50 twists the power lines 51 and 52 (and the first braided conductors 53 and 54), the ground wire 55, and inclusions 57 such as yarns to each other. Then, the outer sides of the twisted members 51, 52, 55, and 57 are wound with a paper tape 58 so as to cover the insulating sheath 59 so that the cross-sectional shape of the power feeding cable 50 becomes a perfect circle.

  In such a power feeding cable 50, the power lines 51 and 52 are covered with the first braided conductors 53 and 54 as described above. For this reason, each first braid is arranged between the power lines 51 and 52 in the power supply cable 50 at any position except for both ends of the power supply cable 50 (portions connected to the welding timer 10 and the welding transformer 20). The conductors 53 and 54 are disposed.

  Below, with reference to FIG. 1, operation | movement of the resistance welding apparatus 1 is demonstrated. In the following, for convenience of explanation, it is assumed that an operator holds the welding gun 30 and performs resistance welding work on each workpiece W / W.

  First, the welding transformer 20 and the welding gun 30 are moved to the workpieces W and W set on the jig 2, and the welding positions of the workpieces W and W are held by the electrodes 31 and 31 of the welding gun 30.

  After the welding positions of the workpieces W and W are held between the electrodes 31 and 31, power supply from the welding timer 10 to the welding transformer 20 is started. At this time, a high voltage (for example, a voltage of 400 V) is applied to the power feeding cable 50.

The welding transformer 20 transforms the high voltage into a low voltage (for example, a voltage of 400 V to 30 V or less), and causes a welding current to flow to the electrodes 31 and 31 (each work W and W) of the welding gun 30. At this time, the workpieces W and W are pressurized by the cylinder 32 of the welding gun 30.
Thereby, each workpiece | work W * W is joined.

  Such a resistance welding apparatus 1 allows energy to be used efficiently because the welding current flows through each workpiece W / W without using the secondary cable 150 (see FIG. 8).

  In the resistance welding apparatus 1, the power supply cable 50 to which a high voltage is applied moves as the welding transformer 20 and the welding gun 30 move. That is, in the resistance welding apparatus 101 in which the welding transformer 120 and the welding gun 130 are separately arranged, the amount of movement is very large compared to the primary cable 160 to which a higher voltage is applied than the welding timer 110 (see FIG. 8).

  Accordingly, the members 51, 52, 55, and 57 rub against each other on the inner side of the power supply cable 50, and the insulators 51b, 52b, and 55b are likely to deteriorate.

  Further, the current flowing through the feeding cable 50 is smaller than that of the secondary cable 150 of the resistance welding apparatus 101 in which the welding transformer 120 and the welding gun 130 are separately arranged (see FIG. 8). For this reason, the cross-sectional area of the feeding cable 50 is smaller than the end area of the secondary cable 150 (see FIGS. 1 and 8). That is, the feed cable 50 is thinner than the secondary cable 150.

  Therefore, when the welding transformer 20 and the welding gun 30 are moved, when the power supply cable 50 comes into contact with the jig 2 or the workpiece W, a part of the power supply cable 50 is easily damaged.

That is, the resistance welding apparatus 1 is used for an application with a high usage rate although it is difficult to cause damage to the power supply cable 50 when used for an application with a low usage rate (for example, when used for vehicle maintenance). In some cases (for example, when used in a production line), deterioration of the insulators 51b and 52b, damage to the power supply cable 50, and the like are likely to occur.
Therefore, when the resistance welding apparatus 1 is used for an application with a high usage rate, the power supply cable 50 becomes a consumable that needs to be replaced periodically (for example, every half day).

  Hereinafter, the operation of the resistance welding apparatus 1 when the resistance welding apparatus 1 is used for a long time using the resistance welding apparatus 1 (for example, installed in a production line) and the power supply cable 50 is about to be disconnected will be described. This will be described with reference to FIG.

When the power supply cable 50 is about to be disconnected, the power supply cable 50 generates heat, and the insulators 51b and 52b deteriorate.
In the following description, for convenience of explanation, it is assumed that a part P1 of the insulator 52b has deteriorated.

As described above, the power line 52 is covered with the first braided conductor 54. Therefore, when the insulator 52b of the power line 52 is deteriorated and the conductor 52a covered with the insulator 52b is exposed from the insulator 52b, the conductor 52a precedes contact with another conductive member, First, the first braided conductor 54 is contacted.
That is, when the insulator 52b deteriorates due to heat generation of the power supply cable 50, the insulator 52b is cracked or melted, and the conductor 52a is exposed from the insulator 52b, the conductor 52a comes into contact with another conductive member. Before, it comes into contact with the first braided conductor 54 covered on the outer periphery of the power line 52. Thus, when the conductor 52a exposed from the insulator 52b comes into contact with another conductive member, it always comes into contact with the first braided conductor 54.

Both ends of the first braided conductor 54 are connected to the welding timer 10 and the ground terminal of the welding transformer 20 as described above. Therefore, since the first braided conductor 54 functions as a ground wire, a ground fault occurs when the conductor 52a of the power line 52 and the first braided conductor 54 come into contact with each other. That is, when the insulator 52b of the power line 52 deteriorates and the conductor 52a exposed from the insulator 52b comes into contact with another conductive member, a ground fault always occurs.
At this time, the earth leakage breaker 40 detects the occurrence of a ground fault in the power feeding cable 50 (that is, the earth leakage in the power feeding cable 50), and automatically shuts off the power supply to the resistance welding apparatus 1 (arrow shown in FIG. 4). i).

  Even if the insulator 51b of the power line 51 is deteriorated, as in the case of the power line 52, the conductor 51a covered with the deteriorated insulator 51b first comes into contact with the first braided conductor 53 first. Always ground fault. Therefore, the earth leakage breaker 40 detects the occurrence of a ground fault in the power supply cable 50 and automatically cuts off the power supply to the welding timer 10.

According to this, the power feeding cable 50 generates heat, the insulators 51b and 52b of the power lines 51 and 52 are deteriorated, and the conductors 51a and 52a come into contact with the first braided conductors 53 and 54, respectively. At this stage, the resistance welding operation can be automatically interrupted.
In addition, the resistance welding operation can be automatically interrupted before the heat generation of the power supply cable 50 greatly proceeds and the power supply cable 50 ignites.

  Accordingly, even when the power supply cable 50 is about to be disconnected, the resistance welding operation can be interrupted before the resistance welding apparatus 1 is seriously damaged due to the occurrence of a short circuit or ignition of the power supply cable 50. Other equipment). For this reason, the worker can restart the resistance welding work only by exchanging the power supply cable 50.

As described above, the resistance welding apparatus 1 simply covers the power wires 51 and 52 of the power supply cable 50 with the first braided conductors 53 and 54 and connects the first braided conductors 53 and 54 to the ground terminal. It is possible to reliably prevent occurrence of a short circuit and ignition of the power supply cable 50.
Therefore, the occurrence of a short circuit and the firing of the power supply cable 50 can be reliably prevented with a simple configuration, resulting in a low-cost configuration.

The configuration of the power supply cable 50 is not limited to this embodiment. That is, when the conductors 51a and 52a covered with the deteriorated insulators 51b and 52b are exposed when the insulators 51b and 52b of the power lines 51 and 52 are deteriorated, the conductors 51a and 52a are exposed to the first braided conductors. 53 and 54 should just be the structure which contacts first.
Below, the modification of the electric power feeding cable 50 is demonstrated with reference to FIGS.

  The power supply cable 50 does not necessarily have to cover the first braided conductors 53 and 54 on the power lines 51 and 52. For example, the power supply cable 50 has a configuration in which a strip-shaped first braided conductor 60 as shown in FIG. It doesn't matter.

The strip-shaped first braided conductor 60 is disposed in the feed cable 50 so as to straddle between the power lines 51 and 52. That is, the strip-shaped first braided conductor 60 is disposed between the power lines 51 and 52.
Such a strip-shaped first braided conductor 60 has, for example, a shape in which a halfway portion thereof is linear and its both end portions are bent toward the power lines 51 and 52 in a sectional view.

  The strip-shaped first braided conductor 60 is unraveled at both ends thereof and re-shaped so as to form a single line, and is connected to the ground terminal of the welding timer 10 and the welding transformer 20. The strip-shaped first braided conductor 60 is disposed in the power supply cable 50 with a paper tape 60a wound around the outside thereof.

In the power supply cable 50 having such a configuration, when the respective insulators 51b and 52b are deteriorated and the respective conductors 51a and 52a are exposed, the respective conductors 51a and 52a of the respective power lines 51 and 52 have other conductive properties. Prior to the member, the belt-shaped first braided conductor 60 is contacted.
According to this, it is possible to reliably prevent occurrence of a short circuit and ignition of the power feeding cable 50 with a simple configuration.

As shown to Fig.6 (a), the electric power feeding cable 50 may be the structure which only coat | covers each 1st braided conductor 53 * 54 to each power line 51 * 52. In other words, the power supply cable 50 does not necessarily have to place the ground wire 55 (and the second braided conductor 56).
In this case, when the respective conductors 51a and 52a covered by the deteriorated insulators 51b and 52b are exposed at the time of deterioration of the insulators 51b and 52b, the first braided conductors 53 are provided, similarly to the power supply cable 50 of the present embodiment. First, 54 comes into contact with the power lines 51 and 52 first.

As shown in FIG. 6B, the power supply cable 50 only covers the first braided conductor 53 on one of the power lines 51 and 52 (the power line 51 in FIG. 6B). It may be a configuration. That is, the power supply cable 50 may be configured to cover at least one of the conductors 51a and 52a of the power lines 51 and 52 with the first braided conductor 53 (or the first braided conductor 54). .
In this case, when the respective conductors 51a and 52a covered with the deteriorated insulators 51b and 52b are exposed at the time of deterioration of the insulators 51b and 52b, the first braided conductor 53 (or the first braided conductor 54) becomes the conductors 51a. -First contact 52a first.

According to this, it becomes the structure which can prevent short circuit generation | occurrence | production reliably only by twisting together each power line 51 * 52 (and each 1st braided conductor 53 * 54).
That is, compared with the case where the strip-shaped first braided conductor 60 and the power lines 51 and 52 are twisted together, the feeding cable 50 can be easily formed as one cable, and thus the configuration of the resistance welding apparatus 1 can be further improved. It can be simplified.

However, the configuration in which the three electric wires (the power lines 51 and 52 and the ground wire 55) are twisted together like the power supply cable 50 of the present embodiment has two electric wires (that is, the power lines 51 and 52). 52) becomes easier to twist as compared with the case of twisting together.
Therefore, the power supply cable 50 is preferably configured to twist the three electric wires together from the viewpoint of easy formation as a single cable and easy manufacture thereof.

  Further, a power feeding cable 50 as shown in FIG. 7 may be used. The power supply cable 50 shown in FIG. 7 includes two power lines 51 and 52, two ground lines 55 and 55, and a first braided conductor 61.

  The ground wires 55 and 55 are arranged along the circumferential direction of the power supply cable 50 so as to be adjacent to the power wires 51 and 52, respectively.

  The first braided conductor 61 covers the outer peripheral surfaces of the ground wires 55 and 55 except for the portion where the ground wires 55 and 55 face each other centering on the midpoint of the feed cable 50. Then, both end portions of the covered portion are extended so as to pass between the power lines 51 and 52 so that the ground wires 55 and 55 are integrally covered.

  The first braided conductor 61 is loosened at both ends thereof, re-shaped so as to form a single wire, and connected to the welding timer 10 and the ground terminal of the welding transformer 20. The first braided conductor 61 is disposed in the power feeding cable 50 with a paper tape 61a wound around the outside.

  According to this, each power line 51 * 52 is arrange | positioned in the electric power feeding cable 50 in the state cut | disconnected by each earth line 55 * 55 and the 1st braided conductor 61. FIG.

Therefore, when the respective conductors 51a and 52a covered by the deteriorated insulators 51b and 52b are exposed when the insulators 51b and 52b are deteriorated, the first braided conductor 61 (or the respective ground wires 55 and 55) is connected to the conductors 51a. -First contact 52a first. For this reason, the occurrence of a short circuit can be prevented more reliably.
Further, even when a relatively large cross-sectional area is required for the power supply cable 50, it can be easily handled.

DESCRIPTION OF SYMBOLS 1 Welding apparatus 10 Welding timer 20 Welding transformer 30 Welding gun 40 Earth leakage breaker (earth leakage monitoring means)
50 Power supply cable 51/52 Power line 51a / 52a Conductor 51b / 52b Insulator 53/54 First braided conductor (shielding member)

Claims (4)

A welding gun that applies welding current while applying pressure to the workpiece;
A welding transformer that is integrally formed with the welding gun and that passes the welding current through the welding gun;
A welding timer for supplying power to the welding transformer;
A power supply cable connecting the welding transformer and the welding timer so that electric power can be supplied from the welding timer to the welding transformer;
A leakage monitoring means for monitoring leakage in the power supply cable;
Comprising
The feeding cable is
Two power lines for supplying electric power to the welding transformer, having a conductor and an insulator covering the conductor, arranged in a state spaced apart from each other in the power feeding cable, and
A shielding member disposed between the power lines and grounded;
Comprising
Resistance welding equipment. The shielding member is
Covering at least one of the conductors of each power line,
The resistance welding apparatus according to claim 1. The feeding cable is
A ground wire twisted together with each of the power lines and the shielding member;
The resistance welding apparatus according to claim 2. The ground wire is
Two are arranged so as to be adjacent to each power line along the circumferential direction of the power supply cable,
The shielding member is
The ground wires are integrally covered so as to pass between the power lines.
The resistance welding apparatus according to claim 3.

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