JP3334626B2 - DC arc welding machine driven by internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC arc welding machine driven by an internal combustion engine to obtain a voltage used for DC arc welding using a magnet generator driven by the internal combustion engine as a power supply.

[0002]

2. Description of the Related Art An internal combustion engine driven DC arc welder includes an internal combustion engine, a welding generator driven by the internal combustion engine, and a rectifier circuit for rectifying the output of the welding generator.
The DC output voltage obtained from the rectifier circuit is supplied between the welding torch and the base material to perform welding.

[0003] As a welding generator, a magnet generator including a flywheel magnet rotor and a stator in which a generating coil is wound around a multi-pole armature core is often used. In a conventional welding machine of this type, an output current of several hundred amperes is obtained by connecting the generating coils in three phases and performing full-wave rectification on the output.

FIG. 11 shows an electrical configuration of a conventional DC arc welding machine driven by an internal combustion engine.
G ′ is a star-connected U-W three-phase power generation coil Lu-L
REC 'is a rectifier circuit for full-wave rectifying the output of the magnet generator MG', CH is a reactor, Df
Is a flywheel diode, t1 and t2 are a pair of welding load connection output terminals to which the welding torch T and the base material (material to be welded) W are connected, respectively, and CD is a current detector for detecting the welding current Idc.

[0005] The rectifier circuit REC 'includes diodes Da' to D
c 'and the thyristors Sa' to Sc 'are connected in a bridge manner. A positive output terminal of the rectifier circuit REC' is connected to one output terminal t1 through a reactor CH, and to a negative output terminal. The terminals are respectively connected to the other output terminal t2. Rectifier circuit REC
The positive output terminal and the negative output terminal of the rectifier circuit REC 'are connected to the cathode and the anode of the flywheel diode Df, respectively, and are connected to the circuit connecting the negative output terminal of the rectifier circuit REC' and the output terminal t2. Current detector CD
Is attached.

The thyristors Sa 'to S of the rectifier circuit REC'
A thyristor trigger circuit ST 'is provided to control c'. The thyristor trigger circuit ST ′ uses the output of the power generation coil Lo provided together with the power generation coils Lu to Lw in the magnet generator MG ′ as a power supply voltage,
The thyristors Sa 'to Sc' receive the detection signal of the welding current Idc obtained from D and the setting signal Vis for giving the set value of the welding current, and keep the welding current Idc detected by the current detector CD at the set value. Is controlled. The thyristor trigger circuit ST 'includes thyristors Sa' to Sc.
An adjustment dial for adjusting the conduction angle of 'is provided, and by adjusting the adjustment dial, the welding current Idc can be appropriately adjusted.

The output voltage versus output current characteristic (output characteristic) of the welding machine shown in FIG. 11 shows a drooping characteristic as shown by curves a, b,... In FIG. 12, and the welding current Idc depends on the position of the adjustment dial. Are maintained at various set values I1, I2,... In FIG. 12, Vo indicates the no-load output voltage of the magnet generator, and Io indicates the short-circuit current.

In a DC arc welding machine driven by an internal combustion engine, a welding operation is often performed by holding a welding torch by hand, and welding is often performed in a situation where the arc length is likely to change. On the other hand, in order to stably maintain the arc, it is necessary to make the output characteristic of the welding machine closer to the constant current characteristic by making the drop rate of the output voltage of the drooping characteristic tight as shown in FIG. .

When DC arc welding is performed by the welding machine shown in FIG. 11, a predetermined output voltage is generated between the welding output terminals t1 and t2 by adjusting the adjustment dial of the thyristor trigger circuit ST '. After the short-circuit current is caused to flow by bringing the welding torch T into contact with the base material W, the welding torch is separated from the base material to generate an arc between the welding torch and the base material. Thereafter, if necessary, the thyristor trigger circuit ST '
The welding is proceeded while adjusting the magnitude of the welding current so as to keep the arc stable by manually adjusting the adjustment dial of.

In the welding machine shown in FIG. 11, since the output voltage of the rectifier circuit REC 'changes with the change of the instantaneous value of the generator output, when the output of the rectifier circuit REC' is directly applied to the welding load. When the set value of the welding current is reduced, the arc may be interrupted. Therefore, in the welding machine of FIG. 11, by connecting the reactor CH and the flywheel diode Df, the welding current is maintained and smoothed, and the arc is prevented from being broken.

[0011]

In the conventional welding machine shown in FIG. 11, the no-load output voltage is sufficient to make the arc start good, to make the arc continuity good, and to perform stable welding. And the short-circuit current is sufficiently large to obtain an output voltage-output current characteristic.
G ′ needs to be configured.

As shown in FIG. 11, the coils of the generator are connected so as to form a single three-phase power generation coil Lu to Lw, so that a characteristic that a no-load output voltage is high and a short circuit current is large is obtained. For this purpose, the cross-sectional area of the conductors of the coils forming the power generation coils of each phase is made sufficiently large so that a large current can flow through the power generation coils, and the number of turns of the power generation coils is made sufficiently large so that the no-load Since it is necessary to increase the output voltage, there is a problem that the volume occupied by the power generation coil of the magnet generator MG 'increases, and the generator becomes large.

In the welding machine shown in FIG. 11, since all the welding current flows through one rectifier circuit REC ', it is necessary to use expensive diodes having a large current capacity as the diodes and thyristors constituting the rectifier circuit REC'. However, there is a problem that the cost of the welding machine is increased.

Further, when the reactor CH is used as in the welding machine shown in FIG. 11, the copper loss due to the resistance of the reactor and the iron loss caused by the iron core of the reactor become losses, and the efficiency of the generator is reduced. Therefore, it is necessary to use a large generator as the generator, and it is necessary to use a large internal combustion engine to drive the generator, and the entire welding machine becomes larger. There was a problem.

Further, in the welding machine shown in FIG. 11, in order to control the phase of the welding current, it is necessary to provide a current detector CD for detecting a DC current, and the configuration of the thyristor trigger circuit ST 'is complicated. Therefore, there is a problem that the cost increases.

As described above, in a DC arc welding machine driven by an internal combustion engine, the rate of decrease in the output voltage of the drooping characteristic is made tight so that the arc can be stably maintained against a change in the arc length. It is necessary to make the output characteristics of the welding machine closer to the constant current characteristics.However, if the output characteristics of the welding machine are made closer to the constant current characteristics, the current flowing when the torch is brought into contact with the base material at the start of welding is also limited. Therefore, when the set value of the welding current is reduced, a large short-circuit current cannot flow through the torch and the base material, and the starting performance of the arc when the torch is separated from the base material is deteriorated. Therefore, in this type of conventional welding machine, when the set value of the welding current is reduced, the startability of the arc at the start of welding becomes worse,
There was a problem that the workability of welding became worse.

Although it is conceivable to increase the set value of the welding current in order to enhance the startability of the arc, the set value of the welding current is set to an appropriate value according to the base material (material to be welded). Because it is necessary, it cannot be increased unnecessarily. If the welding current is excessive, the penetration will be excessive and the arc will penetrate through the base material, so that good welding results cannot be obtained.

Further, when the output characteristic of the drooping characteristic is lowered so as to bring the output characteristic of the welding machine closer to the constant current characteristic, an operator may erroneously contact the welding torch with the base material during welding (the welding torch and the welding torch). When the arc is extinguished (by causing a transient short circuit with the base material), a sufficiently large current can flow through the welding load even if the welding torch is separated from the base material and the arc is regenerated. As a result, there is a problem that the arc cannot be regenerated and the welding is interrupted.

In order to improve the startability of the arc at the start of welding and the regeneration of the arc when a transient short circuit occurs between the welding torch and the base material, the distance between the welding torch and the base material must be improved. It is desirable to provide the welding machine with a characteristic of increasing the output current when a short circuit occurs (referred to as an arc drive characteristic). However, a DC arc welding machine using a magnet generator as a power source has such a characteristic. Was not done.

An object of the present invention is to provide a DC arc welding machine driven by an internal combustion engine capable of obtaining an output for driving a welding load without using a large-capacity component as a component of the rectifier circuit. It is in.

Another object of the present invention is to provide a DC arc welding machine driven by an internal combustion engine which can stably perform welding without causing arc breakage without using a reactor.

Still another object of the present invention is to provide a DC arc welding machine driven by an internal combustion engine, wherein the magnitude of the welding current can be adjusted without using phase control.

Still another object of the present invention is to improve the startability of an arc at the start of welding and the regeneration of an arc when a transient short circuit occurs between a welding torch and a base material. An object of the present invention is to provide a DC arc welding machine driven by an internal combustion engine as described above.

[0024]

SUMMARY OF THE INVENTION A welding machine according to the present invention includes at least one power generating coil for supplying a voltage having a capability of generating a high voltage required at the time of starting an arc, and a current for maintaining an arc. M (m is an integer of 2 or more) current supply power generating coils having the ability to output power, a magnet generator driven by an internal combustion engine, and a first rectifying output of the voltage supply power generation coils. A rectifier,
A rectifier circuit composed of m second rectifiers for rectifying the outputs of the m current supply coils, and the DC output voltages of all the rectifiers constituting the rectifier circuit are applied in the same polarity. Are provided between the pair of output terminals for welding load connection and the m output coils for current supply and the pair of output terminals, respectively, and are turned on when a trigger signal is given. Current output input switches for allowing the outputs of the second rectifiers to be supplied to a welding load connected between the pair of output terminals, and a set value of a welding current supplied to the welding load. A current setting signal generating device for generating a current setting signal, a current increasing command generating circuit for detecting a voltage between a pair of output terminals and generating a current increasing command signal when the detected voltage is equal to or less than a set value; When the increase command signal is generated If not, a trigger signal is given to a predetermined number (including zero) of current output input switches determined according to the magnitude of the current setting signal in order to obtain a welding current set by the current setting signal, When the current increase command signal is generated, the current setting signal and the current increase command signal are set so that the number of current input switches that provide the trigger signal is increased from the number determined according to the current setting signal. And a trigger control device for controlling supply of a trigger signal to the m current output input switches.

The current output input switch may be an independent switch provided between each current supply generating coil and the output terminal, but in order to simplify the circuit configuration, the second switch is used. Preferably, the rectifier comprises a mixed-bridge full-wave rectifier circuit of a thyristor and a diode, and the thyristor of the rectifier circuit is used as a current output switch.

The voltage generating coil having a capability of generating a high voltage required at the time of starting the arc is a generating coil having a high no-load output voltage, and such a generating coil has a sufficiently large number of turns. Obtainable.

The current supply generating coil for outputting a current for maintaining the arc can be obtained by reducing the number of turns as compared with the voltage supplying generating coil.

With the above configuration, when the welding torch once in contact with the base material is separated from the base material at the start of welding, a high voltage can be applied between the welding torch and the base material from the voltage supply generating coil. As a result, it is possible to improve the ignitability of the arc. Also, as described above, a voltage between the output terminals of the pair is detected, and a current increase command generation circuit that generates a current increase command signal when the detected voltage is equal to or less than a set value is provided. A trigger control device for controlling the supply of a trigger signal to the m current output switches is provided, and the number of current output switches to be turned on when a current increase command signal is generated is determined by the current setting signal. If the torch and the base material are short-circuited when the torch and the base material are short-circuited when the torch is brought into contact with the base material at the start of welding, the number of switches for turning on the current output can be increased. By increasing the flowing current, it is possible to easily generate an arc when the torch is separated from the base material, and it is possible to improve the startability of the arc.

As described above, according to the present invention, a high voltage can be supplied to the welding load from the voltage supply coil at the start of welding, and a large current can be supplied from the current supply coil. Therefore, it is possible to improve the startability of the arc and to reliably start the arc.

Further, with the above configuration, even when a transient short circuit occurs between the torch and the base material during welding, a current increase command signal is generated from the current increase command generation circuit, and trigger control is performed. Since the number of current output switches to be turned on by the device can be increased, the welding current can be increased to facilitate arc regeneration,
Interruption of the welding operation can be prevented, and the welding operation can be improved.

As described above, when the switch means is provided between each current supply coil and the output terminal, the number of switch means to be turned on is changed to change the number of the switch means to be turned on, thereby providing the current supply coil connected to the welding load. Can be changed to adjust the magnitude of the welding current. And in the magnet generator,
Since the output characteristics can have drooping characteristics, the welding current can be adjusted to an appropriate value without performing the phase control of the welding current.

The voltage-supply generating coil needs to be configured to generate a high voltage required at the time of starting the arc, so that it is necessary to increase the number of turns. Since it is not necessary to increase the size, the conductor can be wound using a conductor having a relatively small cross-sectional area so as not to become large.

Further, since the power supply coil for current supply is intended mainly to supply a large current necessary for maintaining the arc, it is necessary to increase the cross-sectional area of the conductor. Since it is not necessary to generate a high voltage, the number of turns can be reduced so as not to become large.

As described above, when the power generation coil is divided into the voltage supply coil and the current supply coil, both the power generation coils can be made small, so that the magnet generator can be prevented from becoming large. .

With the above configuration, it is not necessary to provide a reactor between the power generating coil and the output terminal of the welding machine, so that the power generation efficiency can be increased by reducing the loss, and the same welding load can be obtained. Can use a magnet generator smaller than before.

In a preferred embodiment of the present invention, a flywheel magnet rotor attached to an output shaft of an internal combustion engine and 6n (n is an integer of 2 or more) salient pole portions provided radially as a magnet generator. And a stator formed by winding a coil around each salient pole portion of the armature core having a total of 2n coils composed of three coils wound around three adjacent salient pole portions of the armature core When the group is connected in three phases, 1
Two voltage-supplying three-phase power generation coils that are arranged at an angular interval of 80 degrees and generate a high voltage required at the time of starting an arc, and 2n-2 that outputs a current for maintaining the arc
One having three current supply three-phase power generation coils is used.

In this case, the rectifier circuit includes two first rectifiers for rectifying the outputs of the two voltage supply three-phase power generation coils, and one and the other of the upper and lower sides of the bridge circuit by a thyristor and a diode, respectively. The mixed bridge full-wave rectifier is configured to rectify the outputs of 2n-2 current-supplying three-phase power generating coils.
It is preferable to use n-2 second rectifiers. When the second rectifier is configured in this manner, the thyristor forming the second rectifier can be used as a current input switch, so that the circuit configuration is simplified as compared with a case where a current input switch is separately provided. be able to.

As described above, when the second rectifier is used as a mixed-bridge full-wave rectifier and the thyristor of the rectifier is used as a switch for turning on current output, 2n-2 is used in response to the current setting signal and the current increase command signal. A trigger control device is provided for controlling the supply of the trigger signal to the thyristors of the second rectifier.

This trigger control device has a predetermined number (including zero) determined according to the magnitude of the current setting signal in order to obtain the welding current set by the current setting signal when the current increase command signal is not generated. ), A trigger signal is supplied to the thyristor of the second rectifier, and when the current increase command signal is generated, the number of the second rectifiers that supply the trigger signal to the thyristor is determined by the number determined according to the current setting signal. So that the supply of the trigger signal to the thyristors of the 2n−2 second rectifiers is controlled according to the current setting signal and the current increase command signal.

The second rectifier (the second rectifier that supplies a trigger signal to the thyristor) is determined according to the magnitude of the current setting signal.
The number of rectifiers is zero when welding is performed with the welding current set to the minimum value by the current setting signal, and only the output of the voltage supply generating coil is supplied between the output terminals to perform welding. This is the case.

As described above, the flywheel magnet rotor attached to the output shaft of the internal combustion engine, the armature iron core having 6n (n is an integer of 3 or more) radially provided armature cores, When using a magnet generator having a stator consisting of 6n coils wound around 6n salient pole portions of an armature iron core, three adjacent coils of the stator are defined as 2n coils as one coil group. The three coils constituting the 2n-1 coil groups of the three coil groups are arranged in a three-phase star connection or a delta connection, so that the three coils are arranged at an angular interval of 180 degrees and a high voltage required at the time of starting the arc. , And 2n-3 current-supply generating coils that output a current for maintaining an arc, and three remaining coils that form one remaining coil group The two coils of the yl constitutes a further current supply generator coil by V connection,
Another coil may be left as a power supply for the trigger control device. With this configuration, without using an external power supply, or using a part of the output of the voltage generating coil or a part of the output of the current supplying coil,
The trigger control device that controls the supply of the trigger signal to the thyristor can be operated.

[0042]

FIG. 1 shows an example of the electric configuration of a DC arc welding machine driven by an internal combustion engine according to the present invention.
FIG. 4 to FIG. 4 show a configuration example of a magnet generator used in the welding machine.

The magnet generator MG used in this example is, as shown in FIGS. 2 and 3, a crankshaft 4 (FIG.
) And an ignition generator 2 fixed to the internal combustion engine
And a stator 3 disposed inside the flywheel magnet rotor 1 and fixed to an engine (not shown).

The flywheel magnet rotor 1 has a peripheral wall 1
01a, a bottom wall 101c having a rotating shaft mounting boss 101b formed thereon, and a protruding ridge 101a1 formed on the outer periphery of the peripheral wall 101a in a state shifted to the bottom wall 101c side. Cast iron flywheel 101,
The pole piece 10 is disposed in a magnet mounting recess 101d formed on the outer periphery of the flywheel by cutting out a part of the ridge 101a1 on the outer periphery of the flywheel 101.
2 and a permanent magnet 104 for ignition fastened to the flywheel by bolts 103, and an annular yoke 1 fitted and fixed to the inner periphery of the peripheral wall portion 101a of the flywheel 101.
05 and 16 permanent magnets M1 to M16, which are arranged at equal intervals in the circumferential direction of the flywheel and are fixed to the inner periphery of the yoke 105.

As shown in FIG. 3, a tapered portion formed at one end of the crankshaft 4 of the internal combustion engine is fitted in a tapered hole provided in the boss portion 101b of the flywheel. A nut 5 is screwed into the formed screw portion 4a, and the flywheel magnet rotor 1 is coupled to the crankshaft by tightening the nut.

The permanent magnet for ignition 104 is made of a ferrite magnet, and a magnetic pole (S in the illustrated example) on the opposite side of the pole piece 102 of the permanent magnet 104 is provided on the outer periphery of the ridge 101a1 on both sides of the magnet mounting recess 201d. Poles are derived, and these poles and the poles (N in the example shown) that appear on pole piece 102
) Form a three-pole ignition magnet field on the outer periphery of the flywheel.

The ignition generator 2 includes an ignition permanent magnet 104.
A substantially U-shaped ignition-generating core 201 having magnetic pole portions 201a, 201a opposed to the ignition magnet field formed on the outer periphery of the flywheel, and an ignition coil 202 wound around the iron core. The ignition coil comprises a component (not shown) of an ignition circuit for controlling the primary current of the ignition coil, and a resin mold portion 203 covering the components of the ignition coil 202 and the ignition circuit. Ignition core 201 for ignition
Are fixed to a mounting portion provided in a case of an engine (not shown) with bolts, and the magnetic pole portions 201a and 201
1a is opposed to the outer periphery of the ridge 101a1 on the outer periphery of the flywheel via a predetermined gap.

In this example, the primary coil of the ignition coil 202 also serves as an ignition power supply coil, and an AC voltage is induced in the primary coil in synchronization with the rotation of the engine. An ignition circuit (not shown) arranged in the mold section 203 together with the ignition coil 202 causes a sudden change in the current flowing through the primary coil when a voltage is induced in the primary coil of the ignition coil, thereby reducing the current of the ignition coil. A high voltage for ignition is generated in the next coil. This high voltage for ignition is applied to a spark plug attached to a cylinder of the engine through a high voltage cord 204. In the illustrated example, an ignition device for an internal combustion engine is constituted by the ignition coil 202 and an ignition circuit (not shown) arranged in the mold part 203 together with the ignition coil. The ignition circuit for controlling the primary current of the ignition coil may be arranged outside the mold section 203.

The yoke 105 fixed to the inner periphery of the peripheral wall portion 101a of the flywheel is formed in a ring shape from a magnetic material having better magnetic properties than cast iron constituting the flywheel. The illustrated yoke 105 is a flywheel 1
No. 01 is formed by laminating a predetermined number of silicon steel sheets punched into an annular shape which fits almost without gaps on the inner circumference of the peripheral wall portion. This yoke 105 is a flywheel 1
No. 01 is press-fitted to the inner periphery of the peripheral wall portion 101a and fixed to the flywheel. Permanent magnets M1 to M16
Are made of rare-earth magnets in the shape of a rectangular plate curved in an arc shape, and these magnets are arranged at equal angular intervals on the inner periphery of the yoke 105 and fixed to the yoke 105 by bonding. Grooves 105a, 105a,... Extending in the axial direction of the yoke 105 are formed in portions of the inner periphery of the yoke 105 located between the magnets M1 to M16. These grooves are formed such that the width of each opening is substantially equal to the interval between the magnets.

The magnetic material having better magnetic properties than cast iron is a material that can flow more magnetic flux than cast iron and has less iron loss, that is, a material having a saturation magnetic flux density and magnetic permeability higher than that of cast iron. It means a magnetic material that is high and has low holding power.

The magnet M1 fixed to the inner periphery of the yoke 105
M16 are alternately magnetized in the radial direction of the flywheel with different directions of magnetization, and these rare-earth magnets form 16 poles in which N poles and S poles are alternately arranged along the circumferential direction of the flywheel 101. Of the main magnet field is formed.

The stator 3 disposed inside the flywheel magnet rotor 1 has a 24-pole armature core 301 and 24 coils L1u, L1v, L1 wound around the armature core.
, L8u, L8v, L8w (see FIG. 4).

As shown in FIG. 4, the armature core 301
Is composed of a 24-pole annular star core consisting of an annular yoke portion Y and 24 salient pole portions P1 to P24 protruding radially from the outer peripheral portion of the yoke portion at equal angular intervals. , Salient pole P
A coil is wound around each salient pole by inserting a coil conductor into a slot formed between 1 to P24.
In the illustrated example, the coils L1u are respectively connected to the salient poles P1 to P3.
To L13, and coils L3u to L3w are wound around the salient pole portions P4 to P6, respectively. Further, coils L5u to L5w are wound around the salient pole portions P7 to P9, respectively.
The coils L7u to L7w are wound around 12, respectively. Similarly, salient pole portions P13 to P15, P16 to P18, P19 to P21 and P
The coils L2u to L2w, L4u to L4w, L
6u to L6w and L8u to L8w are wound.

The armature core 301 is
1 is arranged inside the flywheel 1 while sharing the center axis with the flywheel, and the magnetic pole formed at the tips of the salient poles P1 to P24 of the armature core 301 is composed of magnets M1 to M16. Are opposed to each other via a predetermined gap.

As in the above example, a rare earth magnet is attached to the inner periphery of an annular yoke 105 made of a laminate of steel sheets having better magnetic properties than cast iron. When the main magnet field is formed on the inner circumference of the flywheel by fitting and fixing to the circumference, it is generated from the rare earth magnet, compared with the case where the rare earth magnet is directly fixed on the inner circumference of the cast iron flywheel. Since the magnetic resistance of the magnetic flux passage (yoke 105) can be reduced, the output of the magnet generator can be increased.

Further, since the rare earth magnet has a small thickness, a leakage magnetic flux easily flows from the N pole to the S pole at both ends in the width direction. When the leakage magnetic flux increases, the amount of magnetic flux linked to the power generation coil decreases, and the power generation performance decreases. In the above example, a groove 105a having a width substantially equal to the width of the gap formed between the rare-earth magnets is formed in a portion of the inner periphery of the yoke 105 located between the rare-earth magnets, and the groove 105a of each rare-earth magnet is formed. By increasing the magnetic resistance of the leakage magnetic path formed at both ends in the width direction, the amount of leakage magnetic flux is reduced, and the power generation performance is improved.

When the magnet field of the magnet generator is formed by using the rare earth magnets as described above, a flywheel 101 having the same size as that used in the related art is used, and the stator 3 is enlarged. Output from conventional magnet generators that used ferrite magnets
It is possible to obtain more than twice the output, to make the magnet generator compact, and to obtain the necessary and sufficient power output to drive the welding load.

A blower blade 101e is integrally formed on the outer surface of the bottom wall portion 101c of the hula wheel 101, and the bottom wall portion 101c is formed.
An air inlet 101f is formed in c. Blower 1
Reference numeral 01e sends out the air taken in from the air inlet 101f in the centrifugal direction to generate a flow of cooling air in the flywheel.

In the above-described magnet generator, eight coil groups are formed by using three coils adjacent to the stator as one coil group, and among these coil groups, L1u to L1
.., L7u to L7w are respectively connected in a three-phase star configuration to form seven three-phase power generation coils A1 to A7.

Of the coils L8u to L8w constituting the remaining one coil group, two coils L8u and L8v are V-connected, and the other coil L8w is used alone to supply a trigger signal to a thyristor described later. It is used as a power source of the trigger control device ST for controlling.

The star-connected three-phase power generation coils A1 to A7
Among them, the two power generation coils A1 and A2 arranged at symmetrical positions separated by an angle of 180 degrees are voltage supply power generation coils provided mainly for supplying a high voltage at the time of starting an arc. These generator coils are
It is wound with a sufficiently large number of turns using a coil conductor having a relatively small cross-sectional area.

The other star-connected three-phase power generating coils A3 to
A7 and a V-connected power generating coil A8 are current generating power coils provided mainly for supplying a current necessary for sustaining an arc, and these power generating coils A3 to A8 are power generating coils for voltage supply. It is wound with a smaller number of turns than the power generating coils A1 and A2 using a coil conductor having a larger sectional area than the coils A1 and A2.

As shown in FIG. 1, the power generation coil A1
A8 are supplied through a rectifier circuit REC between a pair of output terminals t1 and t2 of the welding machine to which the welding torch T and the base metal W are respectively connected.

The rectifier circuit REC includes two first rectifiers rectifying the outputs of the two voltage-supply generating coils A1 and A2, respectively.
Rectifiers Re11 and Re12 and a second rectifier R for rectifying the outputs of the six current supply generating coils A3 to A8, respectively.
The DC output terminals on the positive and negative sides of all the rectifiers Re11, Re12, and Re21 to Re26 constituting the rectifier circuit REC are connected in common to a pair of output terminals t1 and t2, respectively. I have. In other words, all the DC output voltages of the rectifiers Re11, Re12, and Re21 to Re26 are output terminals t1 with their polarities matched.
, T2.

The first rectifiers Re11 and Re12 connect the lower and upper sides of the bridge circuit with diodes Da1 to Dc1, respectively.
And a diode bridge full-wave rectifier composed of Da2 to Dc2. The second rectifier Re21 to Re25 is a mixed bridge composed of thyristors Sa to Sc and diodes Da to Dc on one and the other of the upper and lower sides of the bridge circuit. It consists of a three-phase full-wave rectifier. The second rectifier Re26 is a mixed-bridge single-phase full-wave rectifier in which one and the other of the upper and lower sides of the bridge circuit are constituted by thyristors Sa and Sb and diodes Da and Db, respectively.

The output of the power generation coil L8w used alone is input to the power supply terminal of the trigger controller ST through a single-phase bridge full-wave rectifier Reo composed of diodes Da1, Db1 and Da2, Db2. The trigger signals Vg1 to Vg6 are individually applied to the gates of the thyristors Sa to Sc of the rectifiers Re21 to Re26.

In the example shown, the second rectifiers Re21 to Re2
The thyristor of No. 6 constitutes a current output switch.

Between the pair of output terminals t 1 and t 2 of the welding machine,
A current increase command generation circuit B for detecting a voltage between the output terminals of the pair and generating a current increase command signal Q when the detected voltage is equal to or less than a set value is connected. Current increase command signal Q is transmitted to the trigger controller S
T is input to the control input section of T.

FIG. 5 shows an example of the configuration of the current increase command generation circuit B. In this example, the output terminal t1 on the positive polarity side is shown.
Is connected to the anode of a light emitting diode PD through a series circuit of resistors R1 and R2, and a shunt regulator Reg is connected between the cathode of the light emitting diode PD and an output terminal t2 on the negative polarity side. A Zener diode ZD is connected between the connection point of the resistors R1 and R2 and the negative output terminal t2 with its anode directed toward the output terminal t2, and the resistor R2 and the light emitting diode PD are connected by the Zener diode ZD. And shunt regulator Reg
The voltage at both ends of the series circuit is kept substantially constant. A resistance voltage dividing circuit composed of a series circuit of resistors R3 and R4 is connected between the output terminals t1 and t2, and the output voltage Vfe of the resistance voltage dividing circuit is connected to the shunt regulator R
It is input to the control voltage input terminal of eg.

The resistors R1 through R4, the light emitting diode PD, the shunt regulator Reg, and the zener diode ZD constitute a current increase command generation circuit B.

In the current increase command generating circuit B shown in FIG. 5, when the voltage between the output terminals t1 and t2 of the welding machine exceeds the set value, the output voltage Vfe of the voltage dividing circuit composed of the resistors R3 and R4 is output. Is set to be higher than the reference voltage generated by the reference voltage generation circuit in the shunt regulator Reg. When the output voltage Vfe of the voltage dividing circuit is higher than the reference voltage of the shunt regulator Reg, the switch means in the shunt regulator Reg is in the ON state, and a current flows through the resistors R1, R2, the light emitting diode PD, and the shunt regulator Reg. , The light emitting diode PD emits light. In the example shown in FIG. 5, the state in which the light emitting diode PD emits light is a state in which the current increase command signal Q is not generated.

When the welding torch T approaches the base metal W during welding and the voltage (arc voltage) between the output terminals t1 and t2 becomes equal to or less than the set value, the output voltage Vfe of the voltage dividing circuit becomes equal to the voltage in the shunt regulator Reg. Since the voltage falls below the reference voltage, the switch means in the shunt regulator Reg is turned off,
As a result, the current flowing through the resistors R1 and R2, the light emitting diode PD, and the shunt regulator Reg is cut off, and the light emitting diode PD stops emitting light. In the illustrated example, the state in which the light emitting diode PD has stopped emitting light is the state in which the current increase command signal Q is generated. Light generated by the light emitting diode PD is supplied to a control input unit of the trigger control device ST through an optical fiber cable (not shown).

FIG. 6 shows a configuration example of the trigger control device ST. The trigger control device ST shown in FIG. 6 includes a microcomputer 6, and the collector of an NPN-type phototransistor PTr whose emitter is grounded is connected to a current increase command signal input / output port P11 of the microcomputer. Have been. The collector of the phototransistor PTr is connected through a resistor R5 to an output terminal on the positive polarity side of a not-shown constant voltage power supply circuit that outputs a constant DC voltage EB with the output of the rectifier Reo in FIG. Accordingly, when the voltage between the output terminals t1 and t2 of the welding machine exceeds the set value and the light emitting diode PD emits light (when no current increase command signal is generated), the phototransistor PTr is turned on. And the potential of the I / O port P11 of the microcomputer is kept at a low level (substantially at the ground potential). When the voltage between the output terminals t1 and t2 falls below the set value, the light emitting diode PD is issued. Stops (when a current increase command signal is generated)
The phototransistor PTr is turned off at
The potential of the O port P11 is set to a high level.

When the potential of the I / O port P11 is at a low level (hereinafter referred to as L level), the microcomputer 6 determines that no current increase command signal is given, and the I / O port P11 Is set to a high level (hereinafter referred to as H level), it is determined that the current increase command signal has been given.

A circuit which can appropriately change the magnitude of an output signal (digital signal) by a dial operation or the like is provided, and a voltage having a magnitude corresponding to a set value (instruction value) of a welding current is set to a current setting value. A current setting signal generator 7 that outputs a signal Vis is provided, and a current setting signal Vis generated by the current setting signal generator 7 is input to a current setting signal input I / O port P12 of the microcomputer 6. I have.

The microcomputer 6 also has I / O ports P21 to P26 for outputting a trigger control signal.
These I / O ports are connected to NPN type transistors TR1 to TR6 (T
R2 to TR5 are not shown). The collectors of the transistors TR1 to TR6 are connected to a resistor R61.
To R66 (R62 to R65 not shown) are connected to the positive output terminal of a constant voltage power supply circuit (not shown), and the bases of the transistors TR1 to TR6 are connected to resistors R71 to R76, respectively.
(R72 to R75 are not shown) and are connected to an output terminal of a constant voltage power supply circuit (not shown).

The anodes of the diodes D1a to D1c are connected to the collector of the transistor TR1, and the cathodes of the diodes D1a to D1c are connected to the gates of the thyristors Sa to Sc of the rectifier Re21. A resistor Rg is connected between the cathode of each of the diodes D1a to D1c and the ground.

The microcomputer 6 determines that the potential of the I / O port P11 is at the L level (when no current increase command signal is supplied) and the current setting signal V
When the magnitude of is is at a value corresponding to the minimum value of the welding current, all the potentials of the I / O ports P21 to P26 are kept at the H level, and the magnitude of the current setting signal Vis increases. The potentials of the trigger control signal output I / O ports P21 to P26 are sequentially set to the L level in a predetermined order, and the number of trigger control signal output I / O ports in the L level is increased. In the illustrated example, the I / O ports P21 to P26 are ranked in numerical order, and as the current setting signal Vis increases, the I / O ports P21 to P26 are sequentially set to L in numerical order.
Level.

When the potential of the I / O port P11 is set to the H level (when the current increase command signal generating circuit B determines that the current increase command signal Q has been generated), the microcomputer 6 outputs Of the trigger control signal output I / O ports P21 to P26 in the state of H level (the port to be set to L level next when the welding current is increased) is set to L level. To

For example, when all the potentials of the I / O ports P21 to P26 are at the H level, the I / O port P11
Is set to the H level, the I / O port P21
Of the I / O port P of the first order
When the potential of the I / O port P11 is set to H level while only the potential of 21 is at L level, the potential of the next-order I / O port P22 is set to L level.

I / O port P21 of microcomputer
Is at the H level, the transistor TR1 is on, and the anodes of the diodes D1a to D1c in FIG. 6 are kept at the ground potential. In this state, since no trigger signal is given to the thyristors Sa to Sc of the rectifier Re21, the thyristors of the rectifier Re21 maintain the cut-off state. I / of microcomputer 6
When the potential of the O port P21 is set to the L level, the transistor TR1 is turned off. Therefore, a trigger signal is sent from a constant voltage power supply circuit (not shown) to the thyristors Sa to Sc of the rectifier Re21 through the resistor R61 and the diodes D1a to D1c. Vg1 is provided.

I / O port P of microcomputer 6
Transistor T whose base is connected to each of 22 to P25
A circuit similar to the circuit connected to the collector of the transistor TR1 is also connected to the collectors of R2 to TR5 (not shown). When the I / O ports P22 to P25 are set to the L level, respectively. Trigger signals Vg2 to Vg5 are provided to thyristors Sa to Sc of rectifiers Re22 to Re25.

The anodes of two diodes D6a and D6b are connected to the collector of the transistor TR6 whose base is connected to the I / O port P26, and the cathodes of these diodes are connected to the thyristors Sa and S of the rectifier Re26.
When the potential of the I / O port P26 is set to the L level, the trigger signal Vg6 is supplied from the constant voltage power supply circuit (not shown) to the thyristors Sa and Sb of the rectifier Re26 through the diodes D6a and D6b. It is supposed to be.

FIG. 9 is a flowchart showing an algorithm of a main routine of a program executed by the microcomputer 6 of the trigger control device ST shown in FIG.
FIG. 10 is a flowchart showing an algorithm of an interrupt routine executed every time the current increase command signal Q is generated and the potential of the I / O port P11 becomes H level.

The microcomputer 6 executes these programs so that when the current increase command signal is not generated, the microcomputer 6 adjusts the magnitude of the current setting signal to obtain the welding current set by the current setting signal Vis. A trigger signal is provided to a predetermined number (including zero) of the thyristors of the second rectifier determined accordingly, and when the current increase command signal is generated, the number of the second rectifiers that provide the trigger signal to the thyristor is determined. The supply of the trigger signal to the thyristor of the second rectifier is controlled so as to increase the number more than the number determined according to the current setting signal.

The output voltage versus output current characteristics (output characteristics) of the voltage supply generating coils A1, A2 and the current supply generating coils A3 to A8 used in the above welding machine are, for example, as shown by curves a and b in FIG. . The voltage-supply generating coil has characteristics such that the no-load output voltage Voa is high and the short-circuit current Ioa is small, and the current-supply generating coil has the characteristics that the no-load output voltage Vob is low and the short-circuit current Iob is large. .

In the trigger control device ST shown in FIG. 6, when power is supplied to the microcomputer 6, first, step 1 of the main routine in FIG. 9 is performed, and each unit is initialized. Next, in step 2, the current setting signal Vis is read, and the number (including zero) of the second rectifiers that need to turn on the thyristor to obtain the welding current value set by the current setting signal is determined. In order to provide a trigger signal to the thyristor of the second rectifier which needs to be turned on, the I / O ports P21 to P26
Is set to H level or L level.

That is, when the magnitude of the current setting signal Vis is at a value for setting the welding current to the minimum value, the number of the second rectifiers for turning on the thyristor is set to zero, and the I / O ports P21 to P26 are turned off. All potentials are set to H level. At this time, no trigger signal is given to the thyristors of the second rectifiers Re21 to Re26, and since these second rectifiers do not generate an output, the voltage-supply generating coils A1, A
2 is applied between output terminals t1 and t2.

When the welding current value is smaller than the minimum value by x (= 1, 2, 2)
.., 6) When the magnitude of the current setting signal Vis is increased so as to increase the number of steps, the thyristors Sa to Sc of the x-th rectifiers of the second rectifiers Re21 to Re26 are turned on. X of I / O ports P21 to P26
The potential of the I / O port up to the
The potentials of the / O ports P22 to P26 remain at the H level.
At this time, since the trigger control device ST supplies the trigger signal Vg1 to the thyristors Sa to Sc of the second rectifier up to the x-th, the thyristors of the second rectifier Re21 up to the x-th are turned on, and the power supply for voltage supply Along with the rectified outputs of the coils A1 and A2, the rectified outputs of the x current generating coils are supplied between the output terminals t1 and t2.

For example, when the magnitude of the current setting signal Vis is increased so as to increase the welding current value by one step from the minimum value, the thyristors Sa to Sc of the second rectifier Re21 are increased.
Is turned on, the potential of the I / O port P21 is set to the L level, and the potentials of the other I / O ports P22 to P26 are kept at the H level. At this time, the trigger control device ST sends a trigger signal Vg1 to the thyristors Sa to Sc of the second rectifier Re21.
The thyristor of the second rectifier Re21 is turned on, and the rectified output of the current supply coil A3 and the rectified output of the current supply coil A3 are supplied between the output terminals t1 and t2 together with the rectified output of the voltage supply coil A1 and A2. You. When the magnitude of the current setting signal Vis is increased to increase the welding current value by two steps from the minimum value, the thyristors Sa to Sc of the second rectifier Re21 and the thyristors Sa to Sc of the second rectifier Re22 are increased. To turn on the I / O port P21
And the potential of P22 at L level, and the other I / O port P23
To P26 are kept at the H level. At this time, the trigger control device ST applies the trigger signals Vg1 and Vg2 to the thyristors Sa to Sc of the second rectifiers Re21 and Re22, respectively, so that the thyristors of the second rectifiers Re21 and Re22 are turned on, and the power supply for voltage supply is generated. Coil A1, A2
A3 and A3 and A3
4 is supplied between the output terminals t1 and t2.

When the welding torch comes into contact with or approaches the base material after the welding is started and after the welding is started, and the voltage between the output terminals t1 and t3 becomes lower than the set value, the current shown in FIG. Light emitting diode P of increase command generation circuit B
D stops emitting light and the current increase command signal is generated. When the current increase command signal is generated, an interrupt signal is input to the microcomputer, and the interrupt routine shown in FIG. 10 is executed.

In the interrupt routine shown in FIG. 10, first, in step 1, the current setting signal Vis is read, and I / O is performed to obtain a welding current value corresponding to the read current setting signal.
It is determined that the x-th port of the O ports P21 to P26 should be set to the L level. The content of the process performed in step 1 is the same as the content of the process performed in step 2 of FIG. Next, in step 2 of FIG. 10, 1 is added to x determined in step 1, and in step 3, the x-th port of the I / O ports P21 to P26 is set to L level and determined in accordance with the current setting signal. The trigger signal is controlled by the thyristors of the x-th rectifiers of the second rectifiers Re21 to Re26 so as to supply the welding load with a welding current one level larger than the welding current value. Then, the process returns to the main routine.

The set value of the arc voltage (the voltage between the output terminals of the welding machine) is set to, for example, about 10 [V].

As described above, when the welding torch contacts or approaches the base material, a current increase command signal is generated,
By increasing the number of current supply generating coils connected between the output terminals so that a welding current larger than the welding current value determined by the current setting signal can be supplied, the startability of the arc at the start of welding is improved. And the regeneration of the arc when a transient short circuit occurs during welding can be facilitated.

Curves a to g shown in FIG. 8 represent output voltage Vdc versus output current when the welding current shown in FIG. 1 is varied to change the set value of the welding current by changing current setting signal Vis. It shows an example of the actual measurement result of the characteristic Idc characteristic. In this example, in a room at 24 ° C., the rotation speed of the generator is set to 3
The output voltage and output current were measured by connecting load resistors having various resistance values between the output terminals t1 and t2 at 600 rpm.

In FIG. 8, curve a represents the second rectifier Re2.
In the case where all the thyristors 1 to Re26 are turned off and only the outputs of the voltage supply generating coils A1 and A2 are supplied to the welding load, the curves b to g respectively represent the curves of the second rectifiers Re21 to Re26. x-th (x = 1,2, ...,
Give trigger signal to rectifier thyristor up to 6),
This shows a case where the number of current supply generating coils connected between output terminals is increased. That is, curves b, c, and d indicate that power is supplied to the load from the power generating coils A1 to A3, power is supplied to the load from the power generating coils A1 to A4, and power is supplied to the load from the power generating coils A1 to A5. Curves e, f, and g show the case where power is supplied to the load from the power generation coils A1 to A6, the case where power is supplied to the load from the power generation coils A1 to A7, and the power is supplied to the load from the power generation coils A1 to A8, respectively. This shows a case in which it is supplied.

As is apparent from FIG. 8, according to the present invention, the welding current having various magnitudes is provided by providing a constant current characteristic suitable for maintaining the arc without controlling the phase of the welding current. Obtainable.

A straight line h shown in FIG. 8 shows a transition of the output voltage when the arc drive characteristic is obtained, and welding is performed at a predetermined operating point on each of the curves a to f. In this state, when the voltage between the output terminals t1 and t2 falls below the set value (10 [V] in the example of FIG. 8), the output voltage shifts along the straight line h to the curves b to h, and the welding current is reduced. To increase.

For example, when welding is performed with the current setting signal Vis set to the minimum value, the output characteristic is represented by a point pq-
When the voltage between the output terminals becomes equal to or less than the set value (10 V), the output characteristic shifts to the curve b and the welding current increases. In the above apparatus, the current increase command generation circuit B is omitted, and trigger control is performed to supply a trigger signal to the thyristors of the second rectifiers Re21 to Re26 so that a predetermined welding current flows according to the current setting signal Vis. Assuming that the device ST is configured, the output characteristic when only the rectified output of the power generation coils A1 and A2 is supplied between the output terminals while minimizing the current setting signal Vis is shown in FIG.
The curve a of FIG. In this case, the current flowing when the welding torch is brought into contact with the base material is about 50 [A]. However, as in the present invention, the current increasing command generating circuit B and the trigger control device ST are provided to provide a welding machine. If the output characteristics are given arc drive characteristics, the current flowing when the welding torch is brought into contact with the base material can be increased to about 75 [A].
Arc starting properties and arc regeneration at the time of transient short circuit can be facilitated.

With the above configuration, when the torch is separated from the base material at the time of starting the arc, a high voltage can be supplied between the torch base materials from the power supply coils A1, A2 having a high no-load output voltage. In addition, at the time of starting the arc, a current increase command is generated, and a current larger than the welding current set by the current setting signal can be supplied to the welding load, so that the startability of the arc can be improved.

Since the magnitude of the welding current can be appropriately adjusted by changing the magnitude of the current setting signal and adjusting the number of current supply generating coils to be supplied, a circuit for controlling the phase of the welding current is omitted. Thus, the configuration of the control circuit unit can be simplified.

With the above configuration, the number of turns of the voltage supply coils A1 and A2 must be increased. However, since these coils only have to perform a function of supplying a high voltage mainly at the time of starting the arc. It can be wound using a conductor having a small cross-sectional area. Therefore, the power supply coils A1 and A2 for voltage supply can be configured without being so large.

The power supply generating coils A3 to A8 are
Since it is necessary to output a large current, it is necessary to perform winding using a conductor having a large cross-sectional area.However, since the number of turns of these power generation coils may be small, these power generation coils may be configured to be small. it can.

Therefore, with the above-described configuration, the magnet generator can be made more compact than a conventional welding machine in which it is necessary to use a conductor having a large cross-sectional area to wind a number of turns of the power generating coil. be able to. Further, when the main magnet field is formed by using a rare earth magnet as in the above example, the magnet generator can be further reduced in size.

In the above example, three voltage generating coils and three current generating coils (excluding the power generating coil A8) are used.
Although the power generation coils are configured in a single phase, these power generation coils may be single-phase or multi-phase power generation coils.

In the above example, the V-connected power generation coil A
8 is treated as a single-phase coil, but the V-connected power generation coil A8 is treated as a three-phase power generation coil, and the rectifier Re2
6 may be a mixed-bridge three-phase full-wave rectifier.

In the above example, the power supply generating coil is
Although at least one power supply coil for voltage supply is required, the number is not limited to the above example.

Further, in the above example, six power supply generating coils are provided, but a plurality of current supplying power generating coils may be provided, and the number is not limited to the above example.

In the above example, the rotor of the magnet generator is 16
It is configured with poles and the stator is configured with 24 poles, but the magnet generator is composed of a multi-pole magnet rotor and a multi-pole stator mounted on the output shaft of the internal combustion engine. Well, it is not limited to the above example. For example, a radially provided armature core having 6n (n is an integer of 3 or more) salient pole portions and 6n coils wound around the 6n salient pole portions of the armature core, respectively. And a multi-pole (for example, 4n-pole or 6n-pole) flywheel magnet rotator, and three adjacent coils of the stator are regarded as one coil group and the 2n coil groups are used. The three coils constituting each of the 2n-1 coil groups are three-phase star-connected or delta-connected to form 2n-1 three-phase power generation coils, and the remaining one coil group is constituted by 3 It is also possible to use a magnet generator in which two of the coils are V-connected.

In this case, of the 2n-1 three-phase power generation coils, two three-phase power generation coils arranged at an angle of 180 degrees are used.
The phase power generation coil is a voltage supply power generation coil that generates a high voltage required at the time of starting the arc, and the coils constituting the two voltage supply power generation coils are wound with more turns than the other coils. In addition, the 2n-2 power generation coils including the other 2n-3 three-phase power generation coils and the V-connected power generation coils are current supply power generation coils that output a current necessary to maintain the arc, The coils constituting the 2n-2 current supply power generation coils are wound with a smaller number of turns than the coils constituting the voltage supply power generation coils.

The rectifier circuit REC includes two first rectifiers for rectifying the outputs of the two voltage supply power generation coils, and 2n-2 pieces for rectifying the outputs of the 2n-2 current supply power generation coils. A second rectifier,
The DC output voltages of all the rectifiers constituting the rectifier circuit are applied between the pair of output terminals t1 and t2 with their polarities matched. Each second rectifier is constituted by a mixed-bridge full-wave rectifier in which one and the other of the upper and lower sides of the bridge circuit are respectively constituted by thyristors and diodes.

The thyristor trigger circuit uses one coil other than the three-phase connected coil and the V-connected coil as a power supply and outputs the outputs of the 2n-2 second rectifiers between a pair of output terminals t1 and t2. To selectively apply a trigger signal to the 2n-2 second rectifier thyristors in order to selectively apply the thyristors.

As described above, the power supply coil for supplying voltage
When the two power supply generating coils are provided at intervals of 180 degrees in the case of providing one, the impact caused by a large short-circuit current flowing when the welding torch and the base material are short-circuited at the time of starting the arc can be balanced. The shock that sometimes occurs can be reduced.

In the example shown in FIG. 1, one coil L8w is used to supply power to the thyristor trigger circuit. However, using the power supply of the thyristor trigger circuit as another power supply, all the current supply coils A3 to A8 are used. It may be a three-phase power generation coil.

In the above example, the current-supply generating coil A3
The second rectifiers Re21 to Re26 for rectifying the output of A6 to A6 are mixed-bridge full-wave rectifiers, and the thyristors of these rectifiers are used as switches for turning on the current output to turn on the thyristors of any rectifiers. Although the output of an arbitrary current supply coil is applied between the output terminals t1 and t2, in the present invention, switch means is provided between each current supply coil and the pair of output terminals t1 and t2. The switching means may be provided so as to be able to selectively apply the output voltage of each current supply generating coil between the pair of output terminals by turning on and off each switching means, and the switching means is not necessarily a part of the rectifying circuit. Is not limited to the thyristor.

[0116]

As described above, according to the present invention, a large number of coils provided in a magnet generator are divided into at least one voltage supply coil and a plurality of current supply coils. The output of the supply coil and the output of a predetermined number (including zero) of the plurality of current supply coils selected from the plurality of current supply coils can be supplied between the output terminals. Controls the current increase command generation circuit that generates a current increase command signal when the voltage between the output terminals is less than the set value, and controls the supply of the trigger signal to the current output switch according to the current setting signal and the current increase command signal The number of current output switches to be turned on when a current increase command signal is generated is increased from the number determined by the current setting signal, so that the It is possible to increase the current flowing when the torch is brought into contact with the base material, and to increase the voltage applied between the torch base materials when the torch is separated from the base material to improve the arc starting performance. it can.

Further, according to the present invention, even when a transient short circuit occurs between the torch and the base material during welding, a current increase command signal is generated from the current increase command generation circuit, and a trigger control device is provided. The number of switches for turning on the current output can be increased to increase the welding current, making it easier to regenerate the arc, preventing the welding work from being interrupted, and improving the welding workability. Can be improved.

Further, according to the present invention, it is not necessary to provide a reactor that generates copper loss and iron loss between the rectifier and the output terminal. In combination with the fact that there is no need to use a generating coil, it is possible to prevent the magnet generator from increasing in size.

Further, according to the present invention, since the welding current can be adjusted by the number of power supply coils to be supplied, the phase control circuit of the welding current required in the conventional welding machine can be omitted, and the circuit configuration can be reduced. Can be simplified.

Further, according to the present invention, since it is not necessary to supply a large current to each rectifier, a component having a small current capacity can be used as a component constituting each rectifier, and a circuit is formed using inexpensive components. There are advantages that can be.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an example of an electrical configuration of a DC arc welding machine driven by an internal combustion engine according to the present invention.

FIG. 2 is a front view showing a configuration example of a magnet generator used in the present invention.

FIG. 3 is a sectional view taken along line XX of the generator of FIG. 2;

FIG. 4 is a front view of a stator used in the generator of FIG. 2;

FIG. 5 is a circuit diagram showing a configuration example of a current increase command generation circuit used in the present invention.

FIG. 6 is a circuit diagram showing a configuration example of a trigger control device used in the present invention.

FIG. 7 is a diagram showing one example of output characteristics of a voltage supply coil and a current supply coil used in the present invention.

FIG. 8 is a diagram showing an example of an actual measurement result of an output characteristic of the welding machine according to the present invention.

FIG. 9 is a flowchart showing an example of an algorithm of a main routine of a program executed by a microcomputer constituting the trigger control device of the welding machine according to the present invention.

FIG. 10 is a flowchart showing an example of an algorithm of an interrupt routine of a program executed by a microcomputer constituting the trigger control device of the welding machine according to the present invention.

FIG. 11 is a circuit diagram showing an electric configuration of a conventional welding machine.

FIG. 12 is a diagram showing output characteristics of a conventional welding machine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 hulawheel magnet rotor 101 flywheel 105 yoke M1 to M16 rare earth magnet 3 stator 301 armature core P1 to P24 salient pole L1u to L1w, L2u to L2W,..., L8u to L8w Coil A1, A2 Coil A3 to A8 Current generating coil REC Rectifier circuit Re11, Re12 First rectifier Re21 to Re26 Second rectifier B Current increase command generation circuit ST Trigger control device

Claims (3)

(57) [Claims] 1. A current supply generating coil having at least one voltage supply generating coil capable of generating a high voltage required at the time of starting an arc and having a capability of outputting a current for maintaining an arc. m (m is an integer of 2 or more) magnet generators driven by an internal combustion engine, a first rectifier for rectifying the output of the voltage supply coil, and m current supply generators A rectifier circuit composed of m second rectifiers for rectifying the output of the coil, and a pair for welding load connection to which DC output voltages of all rectifiers constituting the rectifier circuit are applied in a state of being matched in polarity. Output terminals of the m current supply coils and the pair of output terminals, respectively, and are turned on when a trigger signal is applied to the m second power supply coils. Rectification M output switches for allowing the output of the heater to be supplied to the welding load connected between the pair of output terminals, and a current setting signal for providing a set value of the welding current supplied to the welding load. A current setting signal generating device that generates a current increase command generating circuit that detects a voltage between the output terminals of the pair and generates a current increase command signal when the detected voltage is equal to or less than a set value; When no signal is generated, a predetermined number of (including zero) current output switches determined according to the magnitude of the current setting signal are triggered to obtain the welding current set by the current setting signal. Signal, when the current increase command signal has been generated, so as to increase the number of current input switches for providing a trigger signal from a number determined according to the current setting signal,
The m is set according to the current setting signal and the current increase command signal.
And a trigger control device for controlling supply of a trigger signal to the current output input switches. A DC arc welding machine driven by an internal combustion engine. 2. A salient pole portion of an armature core having a flywheel magnet rotor attached to an output shaft of an internal combustion engine and 6n (n is an integer of 2 or more) radially provided salient pole portions. A three-phase connection of a total of 2n coil groups including three coils wound around three adjacent salient pole portions of the armature iron core. , Two voltage-supplying three-phase power generating coils arranged at an angular interval of 180 degrees to generate a high voltage required at the time of starting the arc, and 2n-2 current-supplying coils 3 for outputting a current for maintaining the arc Magnet generator having a three-phase power generation coil; two first rectifiers for rectifying the outputs of the two voltage supply three-phase power generation coils; and a thyristor for each of one and the other of the upper side and the lower side of the bridge circuit And die A rectifier circuit comprising 2n-2 second rectifiers, each of which comprises a mixed bridge full-wave rectifier configured by a circuit, and rectifies the outputs of the 2n-2 current-supplying three-phase power generating coils, respectively. A pair of output terminals to which DC outputs of all rectifiers constituting the rectifier circuit are applied in a state of matching the polarity, and a current setting signal generation for generating a current setting signal for providing a set value of a welding current supplied to a welding load. A device for detecting a voltage between the output terminals of the pair, a current increase command generating circuit for generating a current increase command signal when the detected voltage is equal to or less than a set value, and wherein the current increase command signal is not generated Sometimes, in order to obtain a welding current set by the current setting signal, a trigger signal is supplied to a predetermined number (including zero) of thyristors of the second rectifier determined according to the magnitude of the current setting signal. Giving, when the current increase command signal is generated,
In response to the current setting signal and the current increase command signal, the 2n-2 second rectifiers for providing a trigger signal to the thyristor are increased in number from the number determined according to the current setting signal. And a trigger control device for controlling supply of a trigger signal to a thyristor of the rectifier of Claim 2. 3. A salient pole portion of an armature core having a flywheel magnet rotor attached to an output shaft of an internal combustion engine and 6n (n is an integer of 2 or more) radially provided salient pole portions. And a stator with a coil wound around it.
By setting three coils adjacent to the stator as one coil group, three coils constituting 2n-1 coil groups of the 2n coil groups are connected in a three-phase star connection or a delta connection, respectively. There are two voltage-supply generating coils that are arranged at an angular interval of 180 degrees and generate a high voltage required at the time of starting the arc, and 2n-3 current-supplying generating coils that output a current for maintaining the arc. 3 which constitutes the remaining one coil group
A magnet generator in which two of the two coils are V-connected to form another current supply coil, and two first rectifiers for rectifying the outputs of the two voltage supply coils, respectively. And a 3n star-connected or delta-connected 2n-3 current-supply generating coil comprising a mixed-bridge full-wave rectifier in which one and the other of the upper and lower sides of the bridge circuit are respectively constituted by thyristors and diodes. A rectifier circuit comprising: 2n-2 second rectifiers for rectifying the outputs of a total of 2n-2 current-supply generating coils each comprising one V-connected current-supply generating coil; A pair of output terminals for connecting the welding load applied in a state where the DC output voltages of all the rectifiers constituting the circuit are matched in polarity, and the welding current supplied to the welding load. A current setting signal generating device for generating a current setting signal for providing a constant value; a current increase command generating device for detecting a voltage between the pair of output terminals and generating a current increase command signal when the detected voltage is equal to or less than a set value A circuit, and using one coil other than the three-phase connected coil and the V-connected coil as a power supply to the thyristor of the 2n-2 second rectifiers according to the current setting signal and the current increase command signal. A trigger control device that controls the supply of a trigger signal, wherein the trigger control device is configured to obtain the welding current set by the current setting signal when the current increase command signal is not generated, A trigger signal is given to a predetermined number (including zero) of thyristors of the second rectifier determined according to the magnitude of the current increase command signal. Internal combustion engine driven DC arc welding machine, characterized in that it is configured to increase than the number determined in accordance with the number of the second rectifier to provide a trigger signal to the current setting signal to the thyristor.