JPS646872B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In recent years, automatic arc welding machines such as carbon dioxide gas arc welding machines have penetrated the industrial world at a remarkable rate in response to industrial demands for labor-saving and high-efficiency welding. These automatic arc welding machines generally include (1) a welding power source that is a constant voltage power source, (2) a wire feeding device that feeds a wire-shaped consumable electrode to the welding part,
It consists of (3) a welding torch that energizes the consumable electrode and sends it out to the welding area, and (4) a remote control device that allows the operator to adjust the welding voltage and welding current at hand. The present invention relates to an operation circuit for a welding machine in which the output is controlled at the hands of a worker, and it transmits signals for adjusting the welding voltage and welding current using a cable with a smaller number of cores, and also controls the wire feeding. The purpose is to improve the workability of the welding machine by integrating the device and remote control device.

Generally, an automatic arc welding machine that adjusts the output voltage of the welding machine by changing the firing phase of a thyristor is configured as shown in Figure 1, where 1 is the main transformer section, 2 is the thyristor, 3 is a smoothing circuit section, 4 is a power supply chip, 5 is a welding wire,
6 is a feed roller, 7 is a wire feeding motor,
8 is a thyristor firing phase control circuit, 9 is a variable resistor for setting welding voltage, 10 is a welding wire feeding speed adjustment circuit, 11 is a variable resistor for setting welding current, 12 and 13 are relays, 14, 15 is a DC power supply for driving the relays 12 and 13, 16
17 is an inching push button switch, and 18 is a welding section.

In the above configuration, when welding, the welding operator presses the torch switch 16 to
When the relay 13 operates and the contacts of the relay 13 close, the thyristor ignition phase control circuit 8 and the welding wire feed speed adjustment circuit 10 operate, the thyristor 2 is ignited, and smoothing is applied to the output end of the welding machine. DC voltage appears. Further, by driving the wire feeding motor 7, the welding wire 5 is fed to the welding part 18.

Before starting welding, in order to attach the welding wire 5 to the welding wire feeder and the welding torch, the output end of the welding machine must be in a non-voltage state.
It is necessary to attach the welding wire 5 to a wire feeding device and a welding torch. This operation is called inching, and in this case, the inching push button switch 16
By pressing , the welding wire feeding speed adjustment circuit 10 operates, the wire feeding motor 7 is driven, and the welding wire 5 is attached to the welding wire feeding device and the welding torch by the feed roller 6. I can do it. The wire feeding speed at this time is adjusted by a variable resistor 11.

Figure 2 shows the welding current and welding voltage adjustment circuit, welding start/stop switch circuit, and inching switch circuit in this conventional arc welding machine. The parts on the right side show the parts in the welder's hands.

In this FIG. 2, 19, 20 are control transformers, 21, 22, 23, 24, 25, 26, 27
are rectifier diodes, 28, 29, 30, 31,
32, 33, 34 are resistors, 35, 36 are transistors, 37 is a thyristor that controls the rotation speed of the wire feeding motor 7, 38 is a normally open contact of the relay 13, 39, 40, 41, 42 are capacitors, 4
3 and 44 are constant voltage diodes, 45 is relay 12
46 is the normally open contact of relay 13, 47 is the normally open contact of relay 13.
is an N-gate thyristor, 48 is a pulse transformer,
49 is a thyristor for adjusting the output voltage of the welding machine.

In the conventional output adjustment method during welding shown in FIG. 2, when the operator presses the torch switch 16 at hand, the relay 13 is activated and the normally open contacts 38 and 46 of the relay 13 are closed. Then, current is applied to the wire feeding motor 7 and the oscillation transistor 36 through the contacts 38 and 46 of the relay 13. In an automatic arc welding machine, the welding current is determined by the rotation speed of the wire feeding motor 7, so the welding current can be adjusted by adjusting the wire feeding speed. Here, normally open contact 3 of relay 13
8 and 46 close, the wire feeding motor 7 rotates, and the firing phase of the thyristor 37 is determined by the back electromotive force of the wire feeding motor 7 and the voltage at the gate of the thyristor 37. The back electromotive force is used as a feedback signal, and when the back electromotive force is smaller than the gate voltage, the firing phase of the thyristor 37 is advanced to increase the rotation speed, and when the back electromotive force is higher than the gate voltage of the thyristor 37, the thyristor 37 is turned off. It delays the arc phase and lowers the rotational speed, always trying to maintain a constant rotational speed.

On the other hand, since the voltage at the gate of the thyristor 37 is determined by dividing the voltage across the constant voltage diode 43 using the variable resistor 11 for adjusting the welding current, the wire feeding speed is adjusted by the variable resistor 11. Ru.

Further, the welding voltage is adjusted by controlling the firing phase of the thyristor 49.

A constant potential obtained by dividing the DC voltage by the resistors 32 and 33 is applied to the gate of the N-gate thyristor 47, and when the potential of the anode of the N-gate thyristor 47 becomes higher than the gate, it becomes conductive and the capacitor 40 is charged. The generated charge is discharged through the N-gate thyristor 47, turns on the transistor 36, and is transferred through the pulse transformer 48 to the thyristor 4.
9 is set to fire. The potential of the anode of the N-gate thyristor 47 is the same as that of the capacitor 40.
The charging start potential of the capacitor 40 is determined by the charging potential of the capacitor 40 when the potential of the anode of the N-gate thyristor 47 is higher than the potential obtained by dividing the voltage of the constant voltage diode 44 by the variable resistor 9 for adjusting the welding voltage. Since charging starts from the point where the movable contact of the variable resistor 9 is raised, the charging start voltage of the capacitor 40 increases, the conduction phase of the N-gate thyristor 47 advances, and the welding voltage increases. When the potential of the movable contact of the variable resistor 9 is lowered, the charging start voltage of the capacitor 40 is lowered, and the conduction phase of the N-gate thyristor 47 is delayed.
The welding voltage will be lower. In this way, the welding voltage is adjusted by a voltage signal obtained by dividing a constant voltage by the variable resistor 9.

Next, the operation during inching will be explained.
Inching is possible by pressing an inching push button switch 17 at the operator's hand. When the inching push button switch 17 is pressed, the inching relay 12 operates and the normally open contact 45 of the relay 12 closes, so the wire feeding motor 7
rotates and the wire is fed. The rotational speed control of the wire feeding motor 7 at this time is the same as during welding, and constant speed control is performed by the thyristor 37.
The rotation speed is controlled by a variable resistor 11 for adjusting the welding current.

On the other hand, during inching, since the relay 13 does not operate, no voltage is applied to the transistor 36,
A gate signal for thyristor 36 is not generated. Therefore, the thyristor 49 does not fire, and no voltage is applied from the welding power source.

In conventional welding machines, the operating section and switch section for operating these automatic arc welding machines are attached to the welding power source and the remote controller and wire feeding device, which are connected by a control cable.
As shown in the figure, a variable resistor 9 for adjusting welding current and a variable resistor 11 for adjusting welding voltage are attached to a remote controller, and a wire feeding motor 7 and an inching push button switch 17 are connected to a wire feeding motor 7. The signal from a torch switch 16 attached to the apparatus and attached to the welding torch was typically sent to the welding power source via a wire feeder.
Therefore, conventional welding machines have had to use cables with a large number of fibers for signal transmission between the remote controller and the welding power source.

The present invention has been made in view of the current situation, and the arc welding machine according to the present invention will be described below.
This will be explained using the drawing of FIG.

FIG. 3 shows an arc welding machine according to an embodiment of the present invention, in which 50 is a DC power source, 51
is a relay for controlling the output voltage and wire feed motor in the welding machine, and this relay 51 is connected via the transistor 52 of the DC power source 50. Further, resistors 53, 54, 55 and a constant voltage diode 56 are connected between the base and emitter of the transistor 52 for determining the operating voltage of the transistor 52.

Reference numeral 57 denotes a relay for controlling the wire feeding motor, and this relay 57 is connected to the DC power supply 50 via a transistor 58. Further, a resistor 5 for determining the operating voltage of the transistor 58 is connected between the base and emitter of the transistor 58.
9, 60, and 61 are connected.

62 is a first switch for opening and closing the welding output, 63
is a second switch for inching; 64 and 65 are constant voltage diodes;
8 can be controlled.

The operation of the arc welding machine of the present invention having the above configuration during welding is as follows.

When the welding worker presses the first switch 62 at his/her hand, the connection between the ground wire of the control cable that connects the operating section at the worker's hand and the welding power source and the wire that transmits the signal for opening/closing the relays 51 and 57 is activated. The voltage V _S becomes the voltage drop of the constant voltage diode 65. At this time,
Resistors 59, 60, and 61 are turned on when transistor 58 is turned on.
Constants are selected so that the resistors 53, 54, 55 and the constant voltage diode 56 are connected to the transistor 52.
Since the constant is selected to turn on, relays 51 and 57 operate. This relay 51,
57 operates, the normally open contact 57a of the relay 57
A current flows through the wire feeding motor 7, and the wire feeding motor 7 rotates. Also, relay 5
Since a voltage is applied to the oscillating transistor 36 through the normally open contact 51a of the thyristor 49, a gate signal is applied to the gate of the thyristor 49, the thyristor 49 is fired, and a welding voltage is output from the welding machine.

Further, the operation during inching is as follows.

When the second switch 63 for inching is pressed,
The voltage V _S between the two lines of the control cable is the sum of voltage drops across the constant voltage diodes 64 and 65. At this time, the resistors 59, 60, and 61 are connected to the transistor 5.
8 is turned on, resistors 53,5
4, 55 and the constant voltage diode 56 are selected such that the transistor 52 is turned off, the transistor 58 is turned on, and the transistor 5
2 is turned off and only relay 57 operates. When this relay 57 operates, current flows through the normally open contact 57a of the relay 57 to the wire feeding motor 7, so that the wire feeding motor 7 rotates. That is, in the present invention, the opening/closing of the output of the welding power source and the rotation/stopping of the wire feed motor 7 are controlled by the magnitude of the voltage between the two wires of the cable.

As is clear from the above description, according to the present invention, it is possible to reduce the number of cables connecting the welding power supply unit and the operation unit in the hand of the welding operator, which makes it possible to supply welding machines to the market at low cost. This reduces the number of connections, such as electrical connections, and improves the reliability of contact parts.In addition, the control cable that connects to the wire feeding device and the control cable that connects to the remote control device of the welding machine output can be reduced using cables with fewer fibers. Since it is integrated, the configuration of the arc welding machine is simple and it can have excellent maneuverability.

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram of a conventional arc welding machine, Figure 2 is an electrical circuit diagram of the main parts of the welding machine, and Figure 3 is a schematic diagram of a conventional arc welding machine.
The figure is an electrical circuit diagram of essential parts in an embodiment of the arc welding machine of the present invention. 7... Wire feeding motor, 49... Thyristor, 51, 57... Relay, 62, 63... Switch, 64, 65... Constant voltage diode.

Claims (1)

[Claims] 1. A welding power source, an operating section for selecting and operating the output opening/closing of the welding power source, stopping and starting the feeding of welding wire, and two cables electrically connecting the welding power source and the operating section. , the first cable operates when the voltage between the two cables is equal to or lower than the first predetermined voltage.
a second relay that operates when the voltage between the two cables is lower than or equal to a second predetermined voltage that is higher than the first predetermined voltage; The operating section includes an output switching circuit that opens and closes the output, and a wire feed motor drive circuit that operates according to the operation of the second relay and drives the wire feed motor, and the operation section has the second a first switch that reduces the voltage between the two cables to below the first predetermined voltage;
An arc welding machine characterized in that it is provided with a second switch that lowers the voltage to a predetermined voltage or less.