JP2016074012A - Wire feeder and welding system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which a long-term short circuit between a wire at a tip of a welding torch and a workpiece leads to the shortage of power supply of a power supply circuit built in a wire feeder, thus stopping the feeding of welding wire.SOLUTION: The wire feeder includes: a power supply circuit for generating an internal power supply using electric power supplied from a welding power supply through an electric power line; a communication circuit for communicating with the welding power supply through the electric power line; and a control circuit for controlling a motor on the basis of a motor command signal from the communication circuit. The wire feeder further includes a voltage detection circuit for detecting load voltage. On the basis of the load voltage detected by the voltage detection circuit, the control circuit corrects the motor command signal and outputs the signal as a motor control signal, to control the motor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to wire feeding control of a wire feeding device.

The consumable electrode type welding machine is usually separated into a welding power source device that is not moved due to its weight and a wire feeding device that is carried by an operator when the welding location is changed.
The wire feeder receives a motor command signal from the welding power supply device via the power cable, and controls the rotation of the motor based on the motor command signal.

  The welding system shown in FIG. 4 performs communication of power line conveyance via a power cable between, for example, a welding power supply device WP and a wire feeding device SD in the CO2 / MAG welding method.

As shown in FIG. 4, the welding system includes a welding power supply device WP, a wire feeding device SD, a remote operation device RC, power cables 1 and 2, and a welding torch TH.
One output terminal of the welding power supply device WP is connected to the wire feeding device SD via the power cable 1. The wire feeding device SD feeds the wire to the welding torch TH and causes the tip of the wire to protrude from the tip of the welding torch TH. In a contact chip (not shown) arranged at the tip of the welding torch TH, the power cable 1 and the wire are electrically connected. The other output terminal of the welding power supply device WP is connected to the workpiece W via the power cable 2. The welding power supply device WP generates an arc by applying a high voltage between the tip of the wire protruding from the tip of the welding torch TH and the workpiece W.

  The welding power supply device WP supplies electric power for arc welding to the welding torch TH. The welding power supply device WP includes a power conversion circuit EC, a main control circuit SC, and a first communication circuit PL1.

  The power conversion circuit EC shown in FIG. 4 converts the three-phase AC power input from the power system into DC power suitable for arc welding and outputs it. The three-phase AC power input to the power conversion circuit EC is converted to DC power by a rectification circuit (not shown) and converted to AC power by an inverter circuit. Then, the voltage is stepped down (or boosted) by a transformer, converted into DC power by a rectifier circuit, and output. The power conversion circuit EC also supplies power to the wire feeder SD.

  The main control circuit SC controls the power conversion circuit EC, and is realized by, for example, a microcomputer. The main control circuit SC has a welding voltage output from the power conversion circuit EC as a predetermined set voltage. Control as follows. The main control circuit SC also detects a change in welding conditions, activation of the power conversion circuit EC, abnormality, and the like. Then, the main control circuit SC outputs signals such as a feeding command for the wire feeding device SD and a gas electromagnetic valve opening command to the first communication circuit PL1.

The first communication circuit PL1 shown in FIG. 4 is for performing power line carrier communication with the wire feeder SD via the power cable 1. The first communication circuit PL1 demodulates the signal received from the wire feeder SD and outputs it to the main control circuit SC. The signal received from the wire feeder SD includes, for example, a signal for setting welding conditions, an activation signal for instructing activation of the power conversion circuit EC, and the like. The first communication circuit PL1 modulates a signal input from the main control circuit SC and transmits the modulated signal to the wire feeding device SD. The signal transmitted to the wire feeder SD includes, for example, a detected welding voltage or welding current signal, a signal indicating an abnormality, a feeding command signal, a gas solenoid valve opening command signal, and the like. In addition, the signal transmitted / received between wire feeder SD is not limited to what was shown above.

  The first communication circuit PL1 includes a coil that is disposed around the power cable 1 and magnetically coupled. The first communication circuit PL1 superimposes a signal on the power cable 1 via a coil and communicates with the power line carrier. The first communication circuit PL1 performs BPSK (Binary Phase Shift Keying) modulation on the carrier signal in accordance with the signal input from the main control circuit SC, performs spectrum spread on the modulated signal, converts it into an analog signal, and transmits it.

  The wire feeding device SD shown in FIG. 4 feeds the wire to the welding torch TH. Further, the wire feeder SD supplies a shield gas from a gas tank (not shown) to the tip of the welding torch TH. The wire feeder SD includes a power supply circuit PS, a feeding / communication control circuit CS, a second communication circuit PL2, a motor control circuit MO, and a gas electromagnetic valve GS.

  The power supply circuit PS supplies power to the feeding / communication control circuit CS, the motor control circuit MO, and the gas solenoid valve GS. And the power supply circuit PS receives supply of electric power from the welding power supply device WP via the power cables 1 and 2, converts it into a voltage corresponding to each circuit, and outputs it.

The power supply circuit PS includes a diode D1, a capacitor C1, a first buck-boost circuit A, a second buck-boost circuit B, and a third buck-boost circuit C shown in FIG. The diode D1 is for preventing current from flowing backward from the capacitor C1 to the power cable 1. The capacitor c1 accumulates electric power supplied from the welding power supply device WP via the power cables 1 and 2. The first step-up / step-down unit A, the second step-up / step-down circuit B, and the third step-up / down circuit C adjust the voltages output to the feeding / communication control circuit CS, the gas electromagnetic valve GS, and the motor control circuit MO, respectively. For example, a DC / DC converter is provided. The first step-up / step-down circuit A, the second step-up / down step-up circuit B, and the third step-up / down step-up circuit C respectively supply the voltage across the terminals of the capacitor C1 to the supply / communication control circuit CS, the gas electromagnetic valve GS, and the motor control circuit. The voltage is boosted (or stepped down) to a voltage suitable for MO and output. In addition, the third step-up / down circuit C is configured so that the gas electromagnetic GS is maintained even after the power supply to the feeding / communication control circuit CS and the motor control circuit MO is stopped so that the supply of the shield gas is not stopped until the welding is completed. A capacitor (not shown) is provided so that power can be supplied to the power source.

  Returning to FIG. 4, the feeding / communication control circuit CS controls the wire feeding device SD, and is realized by, for example, a microcomputer. The feeding / communication control circuit CS inputs / outputs various signals to / from the second communication circuit PL2, and also inputs / outputs various signals to / from the remote control device 3. Remote control device RC is for operating welding power supply device WP from a remote position.

  The feeding / communication control circuit CS transmits an activation signal for activating the power conversion circuit EC of the welding power supply device WP from the second communication circuit PL2 via the power cable 1. In addition, when a motor command signal is transmitted from the first communication circuit PL1 via the power cable 1, the feeding / communication control circuit CS controls the motor M to feed the wire to the welding torch TH. Send it out.

The transmission / communication control circuit CS determines whether the power of the power supply circuit PS is sufficient or insufficient based on the voltage across the terminals of the capacitor C1 built in the power supply circuit PS. If it is determined that the power is insufficient, the second communication circuit PL2 A signal indicating power shortage is output to the welding power supply device WP via, the wire feeding is stopped, and the gas solenoid valve 25 is also closed. That is, a problem arises when the power of the power supply circuit PS is insufficient during welding. Therefore, if it is determined that the power is insufficient, the welding is stopped.
The technique described above is disclosed in Patent Document 1.

JP 2003-15445 A

Conventionally, when the wire at the tip of the welding torch and the workpiece are short-circuited for a long time, power shortage occurs in the power supply circuit, and the feeding of the welding wire is stopped. At this time, even if the feeding of the welding wire is stopped, a capacitor is mounted on the power supply portion to the gas solenoid valve so that the power supply to the gas solenoid valve can be continued for about 0.5 seconds, and the welding is completed. Shielding gas can be supplied to prevent blow.
However, welding cannot be continued, which may cause welding defects when welding is resumed. Therefore, it is necessary to control the workpiece so as not to be short-circuited for a long period of time before the workpiece is short-circuited for a long period of time and the output voltage of the power supply circuit is lowered.
Therefore, an object of the present invention is to provide a welding system that suppresses a short circuit for a long time.

In order to solve the above-described problem, the invention according to claim 1 is a power supply circuit that generates an internal power supply using electric power supplied from a welding power supply device via a power line, and the welding power supply device via the power line. In a wire feeder comprising: a communication circuit that communicates with the control circuit; and a control circuit that controls a motor based on a motor command signal from the communication circuit.
The wire feeder is provided with a voltage detection circuit for detecting a load voltage, and the control circuit corrects the motor command signal based on the load voltage detected by the voltage detection circuit and outputs the motor control signal as a motor control signal. It is a wire feeding device characterized by performing.

According to a second aspect of the present invention, the control circuit corrects the motor command signal based on an average voltage value of the detected load voltage and outputs the corrected motor command signal as a motor control signal. It is a feeding device.

The invention according to claim 3 is the wire feeding device according to claim 2, wherein the average voltage value is a value obtained by moving average of the detected load voltage every predetermined time.

In the invention according to claim 4, the control circuit increases the value of the motor command signal to a predetermined value and outputs it as a motor control signal when the average voltage value is a predetermined multiple of a voltage setting value or more. 4. The motor control signal according to claim 2, wherein when the average voltage value is equal to or lower than a predetermined reference voltage value, the value of the motor command signal is reduced to a predetermined value and output as a motor control signal. It is a wire feeding apparatus of description.

In the invention according to claim 5, the control circuit increases the value of the motor command signal by 1.5 times and outputs it as the motor control signal when the average voltage value is twice or more the value of the voltage setting value. 5. The wire feeding device according to claim 4, wherein when the average voltage value is equal to or lower than a predetermined reference voltage value, the value of the motor command signal is multiplied by 0.5 and output as the motor control signal. .

The invention according to claim 6 includes the welding power supply device and the wire feeding device according to any one of claims 1 to 5, and the welding power supply device and the wire feeding device via the power line. It is a welding system characterized by communicating with a feeder.

In the present invention, since a long-term short circuit between the wire at the tip of the welding torch and the workpiece can be suppressed, power shortage in the power supply circuit built in the wire feeding device can be improved. This improvement reduces the stoppage of welding wire feeding, so that welding defects can be suppressed.

It is a block diagram of the welding system of the embodiment of the present invention. It is detail drawing of the control circuit which forms embodiment. It is a wave form diagram explaining operation | movement of embodiment. 1 is a block diagram of a prior art welding system. FIG. It is a detailed view of the power supply circuit of a prior art.

The operation of the embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram of a welding system according to an embodiment of the present invention. In the same figure, the components having the same reference numerals as those in the block diagrams of the prior art welding systems shown in FIGS. 4 and 5 perform the same operations, and thus the description thereof will be omitted.

  The wire feeder SDV shown in FIG. 1 includes a control circuit CC and a voltage detection circuit VO in addition to the power supply circuit PS, the second communication circuit PL2, the motor control circuit MO, and the gas electromagnetic valve GS.

  The voltage detection circuit VO detects a voltage input to the power supply circuit PS and inputs it to the control circuit CC as a voltage detection signal Vo (load voltage).

FIG. 2 is a detailed diagram of the control circuit CC shown in FIG. 1, and is formed of a feeding / communication control circuit CS, an averaging circuit VA, and a command correction circuit GA. The averaging circuit VA averages the value of the voltage detection signal Vo every predetermined time and outputs the averaged signal Va. Alternatively, the average value Va may be obtained by moving and averaging the value of the voltage detection signal Vo every predetermined time.

  The command correction circuit GA increases the value of the motor command signal Iset to a predetermined value when the value of the average signal Va becomes a predetermined multiple of the value of the voltage setting signal Vset set by the remote control device RC. When the motor control signal Ga is output and the value of the average signal Va becomes equal to or lower than a predetermined reference voltage value, the value of the motor command signal is reduced to a predetermined value and output as the motor control signal Ga.

  FIG. 3 is a waveform diagram for explaining the operation of the embodiment. 3, (A) shows the voltage detection signal Vo, (B) shows the voltage setting signal Vset, (C) shows the averaged signal Va, (D) ) Shows a motor command signal Iset, and FIG. 9E shows a motor control signal Ga.

  Next, the operation will be described with reference to the waveform diagram of FIG. At time t = t1 shown in FIG. 3, the voltage detection circuit VO detects a voltage input to the power supply circuit PS and outputs it as a voltage detection signal Vo. The averaging circuit VA calculates the average of the value of the voltage detection signal Vo every predetermined time, and outputs the average signal Va shown in FIG. 3C at time t = t2.

  As shown in FIG. 3 (C), the command correction circuit GA determines whether the voltage setting value Vset is greater than or less than a value αVset, or greater than or less than the reference voltage value Vref, as shown in FIG. When the value of the average signal Va is equal to or less than a value αVset obtained by multiplying the voltage setting value by a predetermined value and equal to or greater than the reference voltage value Vref, the motor control signal Gaset is not corrected without correcting the value of the motor command signal Iset. Output as.

Subsequently, at time t = t2 to t3, the averaging circuit VA calculates an average voltage value Va of the voltage detection signal Vo detected for a predetermined time, and inputs it to the command correction circuit GA.

As shown in FIG. 3C, the command correction circuit GA determines whether the voltage setting value Vset is greater than or less than a value αVset, or greater than or less than the reference voltage value Vref, as shown in FIG. When the average signal Va is equal to or greater than αVset, the motor command signal Iset is increased to a predetermined value and output as the motor control signal Ga.
For example, when the voltage setting value Vset is equal to or greater than the value of the average signal Va, for example, the command correction signal shown in FIG. Output as Ga. This correction speeds up the wire feeding and quickly suppresses the burning of the wire.

At time t = t3 to t4, the averaging circuit VA calculates the average voltage value Va of the voltage detection signal Vo detected for a predetermined time again. At time t = t4, the command correction circuit GA determines that the value of the average signal Va is If it is determined that the voltage set value is equal to or smaller than a value αVset obtained by multiplying the voltage set value by a predetermined multiple, the value of the motor command signal Iset is not corrected and is output as the motor control signal Ga.

From time t = t4 to t5, the averaging circuit VA calculates an average voltage value Va of the value of the voltage detection signal Vo detected for a predetermined time and inputs it to the command correction circuit GA. As shown in FIG. 3C, the command correction circuit GA determines whether the voltage setting value Vset is greater than or less than a value αVset, or greater than or less than the reference voltage value Vref, as shown in FIG. At t5, when the reference voltage value Vref or less, the value of the motor command signal Iset is reduced to a predetermined value and output as the motor control signal Ga.
For example, when the value of the average signal Va becomes a reference voltage value Vref, for example, a value of 5 V or less, the value of the motor command signal Iset is increased by 0.5 times, for example, to the command correction signal Ga shown in FIG. Output as. This correction suppresses long-term short-circuiting by slowing wire feeding.

For example, when the value of the average signal Va continues below the reference voltage value Vref even if it exceeds 0.5 sec, the command correction circuit GA determines that the wire is long-term short-circuited and sets the value of the motor command signal Iset to zero. The control signal Ga is output, and the wire feeding is stopped to release the long-term short circuit.
The averaging circuit VA averages the value of the voltage detection signal Vo every predetermined time and outputs it as an average signal Va. However, the averaging circuit Va averages the value of the voltage detection signal Vo every predetermined time. It is good.

As described above, when the wire at the tip of the welding torch and the workpiece are short-circuited for a long time, the output voltage of the power supply circuit provided in the wire feeding device is reduced by quickly decelerating or stopping the feeding of the welding wire. Since the short circuit can be released for a long time, the power shortage of the power supply circuit of the wire feeder can be solved.

DESCRIPTION OF SYMBOLS 1 Power cable 2 Power cable 3 Control circuit power supply line 4 Gas valve power supply line 5 Motor control power supply line A 1st buck-boost circuit B 2nd buck-boost circuit C 3rd buck-boost circuit AC Commercial AC power supply C1 Capacitor CC Control circuit CS Feeding / communication control circuit D1 Diode EC Power conversion circuit Iset Motor command signal (motor command value)
GA command correction circuit Ga motor control signal Gc solenoid valve drive signal GS gas solenoid valve M motor MO motor control circuit PL1 first communication circuit PL2 second communication circuit PS power supply circuit RC remote control device Rc remote control device signal SC main control circuit Sc Main control signal SD Wire feeder SDV Wire feeder TH Torch VA Averaging circuit Va Average voltage signal (average voltage value)
VO Voltage detection circuit Vo Voltage signal Vset Setting voltage signal (setting voltage value)
Wc1 Welding machine feeder communication signal WP Welding power supply

Claims (6)

A power supply circuit that generates an internal power supply using electric power supplied from a welding power supply device via a power line, a communication circuit that communicates with the welding power supply device via the power line, and a motor command signal from the communication circuit In a wire feeding device comprising a control circuit for controlling a motor based on
The wire feeder is provided with a voltage detection circuit for detecting a load voltage, and the control circuit corrects the motor command signal based on the load voltage detected by the voltage detection circuit and outputs the motor control signal as a motor control signal. A wire feeding device characterized in that The wire feeding device according to claim 1, wherein the control circuit corrects the motor command signal based on an average voltage value of the detected load voltage and outputs the corrected motor command signal as a motor control signal. 3. The wire feeding device according to claim 2, wherein the average voltage value is a value obtained by moving and averaging the detected load voltage every predetermined time.   The control circuit increases the value of the motor command signal to a predetermined value and outputs it as a motor control signal when the average voltage value is equal to or greater than a predetermined multiple of a voltage setting value, and the average voltage value is determined in advance. 4. The wire feeding device according to claim 2, wherein when the voltage is equal to or lower than a reference voltage value, the value of the motor command signal is reduced to a predetermined value and output as a motor control signal. 5. When the average voltage value is twice or more the voltage setting value, the control circuit multiplies the motor command signal value by 1.5 and outputs the motor control signal as the average voltage value. 5. The wire feeding device according to claim 4, wherein when the voltage is equal to or lower than a reference voltage value, the value of the motor command signal is multiplied by 0.5 and output as the motor control signal. The welding power supply device and the wire feeding device according to any one of claims 1 to 5 are provided, and communication is performed between the welding power supply device and the wire feeding device via the power line. A welding system characterized by performing.

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