JP2014184452A - Power supply device for arc welding and control method of power supply device for arc welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device for arc welding (control method) capable of satisfactorily performing arc welding by properly controlling feeding speed of a welding wire.SOLUTION: As feeding control of a welding wire 12, feeding speed Vft of the welding wire 12 is periodically changed so as to switch to an arc period in the neighbourhood of switching from forward feeding to reverse feeding of the welding wire 12, and regulation of the feeding speed Vft of the welding wire 12 is performed in the reverse feeding period. Then, when feeding speed synchronism deviation to the effect that the feeding speed Vft of the welding wire 12 is slow is determined, acceleration control is executed including acceleration in a reverse feeding direction, and when the feeding speed synchronism deviation to the effect that the feeding speed Vft of the welding wire 12 is fast is determined, deceleration control is executed including deceleration in the reverse feeding direction.

Description

  The present invention relates to a consumable electrode type arc welding power supply apparatus and a control method for the consumable electrode type arc welding power supply apparatus.

  In the consumable electrode type arc welding, an arc is generated from the tip of the electrode using the welding wire as the discharge electrode, and welding of the work piece (base material) is performed. However, since the welding wire is consumed by the arc, Welding is performed while feeding the welding wire according to the wear. Further, in this consumable electrode type arc welding, a short-circuit period in which the welding wire comes into contact with the workpiece and an arc period in which the welding wire is separated from the workpiece and causes an arc are alternately generated. In order to perform arc welding appropriately, the welding wire is repeatedly advanced (forward) and retracted (reverse) in accordance with each period (see, for example, Patent Document 1).

Japanese Patent No. 4807474

  By the way, at the time of welding, the distance between the welding torch and the workpiece is relatively changed, for example, the displacement of the welding torch and the surface state of the workpiece. In other words, the distance between the power supply tip of the welding torch for supplying power to the welding wire and the work piece, that is, the distance between the so-called tip base materials may change. It is necessary to change the feeding speed.

  For example, when the forward feed speed of the welding wire is high in a situation where the distance between the tip base materials is shortened, there is a risk that the forward welding operation is performed after the welding wire comes into contact with the workpiece and the welding wire is buckled. If the forward feed speed of the welding wire is slow in a situation where the distance between the tip base materials is extended, the tip of the welding wire and the work piece may be separated from each other and arc breakage may occur. In this way, if the feeding speed of the welding wire is not properly adjusted in response to the change in the distance between the tip base materials, there is a possibility that the welding performance may be deteriorated or the continuation of welding may be hindered depending on the case. .

  The present invention has been made to solve the above-described problems, and an object of the present invention is to appropriately control the feeding speed of the welding wire and perform arc welding satisfactorily and an arc welding power supply apparatus and arc. It is an object of the present invention to provide a method for controlling a welding power supply device.

  A power supply apparatus for arc welding that solves the above-described problems is a short circuit period and an arc period for arc welding in order to perform arc welding of an object to be welded by generating an arc at the tip of the electrode using a welding wire as a discharge electrode. An output control unit that adjusts output power suitable for each period, and forward / reverse feeding of the welding wire to generate a periodic change between a short circuit period and an arc period for arc welding in addition to the consumption of the welding wire by the arc. An arc welding power supply apparatus including a feeding control unit that periodically changes the feeding speed including a synchronization deviation determination unit that determines a feeding speed synchronization deviation of the welding wire with respect to each period. And the feeding control unit periodically changes the feeding speed of the welding wire so as to switch to the arc period in the vicinity of switching from normal feeding to reverse feeding of the welding wire. When the feeding speed of the welding wire is adjusted during the reverse feeding period, and the feeding speed synchronization deviation is determined by the synchronization deviation judgment unit to indicate that the feeding speed of the welding wire is slow. Acceleration control including acceleration in the reverse feed direction is performed, and when the determination of the feed speed synchronization deviation indicating that the feed speed of the welding wire is fast is made in the synchronization deviation determination unit, deceleration including deceleration in the reverse feed direction Implement control.

  According to this configuration, as the welding wire feeding control, the welding wire feeding speed is periodically changed so as to switch to the arc period in the vicinity of the switching from the normal feeding to the reverse feeding of the welding wire, and vice versa. The feeding speed of the welding wire is adjusted during the feeding period. Then, when it is determined that the feeding wire synchronization speed is slow, acceleration control including acceleration in the reverse feeding direction is performed, and the feeding wire synchronization speed is high. When the deviation is determined, deceleration control including deceleration in the reverse feed direction is performed. In other words, when the welding environment changes, such as the distance between the power supply tip of the welding torch and the workpiece to be welded, the so-called tip base metal distance changes, and the situation where the welding wire feeding speed is slow, reverse feeding is performed. Acceleration of the welding wire feeding speed is performed as acceleration control during the period, and when the welding wire feeding speed is high, the welding wire feeding speed is decelerated as deceleration control during the reverse feeding period. Therefore, it is possible to quickly approximate the desired speed in each situation.

  Further, in the above-described arc welding power supply device, it is preferable that the synchronization deviation determination unit determines that a feeding speed synchronization deviation of the welding wire has occurred based on detection of an output voltage during the short circuit period.

  According to this configuration, the determination as to whether or not the welding speed synchronization of the welding wire has occurred is made based on the detection of the output voltage (such as an average voltage) during the short circuit period. That is, the determination of the welding wire feeding speed synchronization deviation is easily performed based on the detected value of the output voltage.

  Further, in the above-described arc welding power supply device, the feeding control unit changes the feeding speed of the welding wire along a periodic change curve, and at the time of adjusting the feeding speed during the acceleration control. Control is performed to advance the phase of the change curve in the reverse feed period until the predetermined speed is reached, and during the deceleration control, the phase of the change curve is set in the reverse feed period until the predetermined speed at the time of adjustment of the feed speed is reached. It is preferable to implement a delay control.

  According to this configuration, the feed control for changing the feed speed of the welding wire along the periodic change curve is performed, and at the time of acceleration control in a situation where the feed speed of the welding wire is slow, the feed speed The phase of the change curve is advanced in the reverse feed period until the predetermined speed at the time of adjustment is reached. Further, at the time of deceleration control in a situation where the feeding speed of the welding wire is high, the phase of the change curve is delayed in the reverse feeding period until the predetermined speed at the time of adjusting the feeding speed is reached. That is, since the control is based on the phase adjustment of the periodic change curve for setting the feed speed of the welding wire each time, it contributes to simplification of the feed control of the welding wire.

  In the above arc welding power source device, the feed control unit changes the feed speed of the welding wire along a periodic change curve, and the amplitude of the change curve is amplitude during the acceleration control. It is preferable to perform control to reduce the reverse curve using a small change curve and to increase the amplitude of the change curve using the large amplitude change curve during the deceleration control.

  According to this configuration, the feed control for changing the feed speed of the welding wire along the periodic change curve is performed, and at the time of acceleration control in the situation where the feed speed of the welding wire is slow, the amplitude of the change curve Is reduced in the reverse feed period using a change curve with a small amplitude. Further, at the time of deceleration control in a situation where the feeding speed of the welding wire is high, the amplitude of the change curve is increased in the reverse feed period using the change curve having a large amplitude. That is, since the control is based on the amplitude adjustment of the periodic change curve for setting the feed speed of the welding wire each time, it contributes to simplification of the feed control of the welding wire.

  In addition, the control method of the power supply apparatus for arc welding that solves the above problems includes a short-circuit period for arc welding in order to perform arc welding of an object to be welded by generating an arc at the tip of the electrode using a welding wire as a discharge electrode. Output control for adjusting the output power to be suitable for each period of the arc period, and the welding wire in order to generate a periodic change between the short-circuit period and the arc period for arc welding in addition to the consumption of the welding wire by the arc. A control method for a power supply apparatus for arc welding that performs feed control that periodically changes the feed speed including reverse feed, wherein the arc period is near the switching from forward feed to reverse feed of the welding wire. The welding wire feeding speed is periodically changed so as to switch to the above, and the welding wire feeding speed is adjusted during the reverse feeding period. A synchronization shift determination is performed to determine a feed speed synchronization shift of the welding wire, and an acceleration control including an acceleration in a reverse feed direction is performed when a determination of a feed speed synchronization shift indicating that the feed speed of the welding wire is slow is made. When it is determined that the feeding speed synchronization deviation is determined to indicate that the feeding speed of the welding wire is high, deceleration control including deceleration in the reverse feeding direction is performed.

  In this configuration as well, the welding wire changes such as the distance between the power supply tip of the welding torch and the workpiece, that is, the distance between the so-called tip base materials changes, and the feeding speed of the welding wire is slow. When the situation is reached, acceleration control including acceleration in the reverse feed direction is performed, and when the welding wire feed speed is high, deceleration control including deceleration in the reverse feed direction is performed. It is possible to approximate to

  According to the power supply apparatus for arc welding and the control method for the power supply apparatus for arc welding according to the present invention, it is possible to appropriately control the feeding speed of the welding wire and perform arc welding satisfactorily.

It is a lineblock diagram of an arc welding machine (power supply device for arc welding) in an embodiment. It is a wave form diagram for demonstrating the control aspect of 1st Embodiment. It is a wave form diagram for demonstrating the control aspect of 1st Embodiment. It is a wave form diagram for demonstrating the control aspect of 2nd Embodiment. It is a wave form diagram for demonstrating the control aspect of 2nd Embodiment.

(First embodiment)
A first embodiment of the arc welding power supply apparatus and the arc welding power supply control method will be described below.

  As shown in FIG. 1, the arc welding machine 10 supplies and holds an electric power to a welding wire 12 as a discharge electrode that generates an arc, together with an arc welding power supply device 11 that generates output power suitable for arc welding. A welding torch 13 is provided, a feeding device 14 that feeds the welding wire 12, and a wire stand 15 around which the welding wire 12 is wound.

  The welding torch 13 is connected to the power supply device 11 via the power cable 16 and receives power supply from the power supply device 11. The welding torch 13 includes a power supply tip 13 a that supplies power to the welding wire 12. The power feed tip 13 a is in electrical contact with the welding wire 12 to supply the output power generated by the power supply device 11 while allowing the feeding operation of the welding wire 12. Such a welding torch 13 is arranged and used so that the welding wire 12 (power supply tip 13a) side faces the workpiece (base material) M to be welded.

  The feeding device 14 includes a motor 14a as a drive source, and pulls the welding wire 12 from the wire stand 15 and sends it to the welding torch 13 by driving the motor 14a. Since the welding wire 12 serving as the discharge electrode is consumed as the arc is generated, the feeding device 14 feeds the welding wire 12 to compensate for the consumption of the welding wire 12. Further, the feeding of the welding wire 12 is not just a one-way / constant-speed feeding mode, but forward (forward feeding) or backward (reverse feeding), and the feeding speed Vft at that time is also changed. Has been done. Such a feeding device 14 (motor 14a) is controlled by the control circuit 20 in the power supply device 11, and switching between forward feeding and reverse feeding (forward / reverse rotation of the motor 14a) in the feeding operation of the welding wire 12, The feeding speed Vft of the welding wire 12 (rotational speed of the motor 14a) and the like are controlled.

  The arc welding power supply device 11 includes a control circuit 20 including a CPU. The control circuit 20 includes an output control unit 20a that generates output power for arc welding, a period detection unit 20b that detects short-circuit / arc periods Ts and Ta, and a feeding control unit 20c that controls the feeding operation of the welding wire 12. And a synchronization deviation determination unit 20d that determines whether or not a feeding speed synchronization deviation of the welding wire 12 has occurred, and controls to appropriately perform arc welding.

  2 and 3, in the consumable electrode type arc welding machine 10 as in the present embodiment, the short-circuit period Ts in which the welding wire 12 contacts the workpiece M and the welding wire 12 is to be welded. Arc periods Ta for generating arcs apart from the object M are alternately generated. The control circuit 20 adjusts the output power (output voltage Vw, output current Iw) by the output control unit 20a and adjusts the welding wire 12 by the feed control unit 20c so that the short-circuit period Ts and the arc period Ta are appropriately generated. The feeding direction and the feeding speed Vft are adjusted. At that time, the control circuit 20 detects the short circuit period Ts and the arc period Ta based on the detection of the output voltage Vw of the power supply device 11 by the period detection unit 20b.

  By the way, the welding environment, such as the relative distance between the power feed tip 13a of the welding torch 13 and the workpiece M, the so-called tip base material distance L, changes. In this case, unless the feed speed Vft of the welding wire 12 is changed in accordance with the distance L, the periodic generation of the short-circuit period Ts and the arc period Ta in arc welding is adversely affected, and arc welding cannot be performed appropriately. There is a fear. Therefore, the control circuit 20 adjusts the feeding direction of the welding wire 12 and the feeding speed Vft as well as the adjustment of the output power.

  As shown in FIGS. 2 and 3, in the situation before the change in the distance L between the base metals (before time A1, A2), a short circuit that can be understood from the output voltage (arc voltage) Vw and the output current (welding current) Iw. With respect to the change between the period Ts and the arc period Ta, the feed speed Vft of the welding wire 12 is changed on a sinusoidal change curve Xa including positive and negative (forward / reverse feed). In other words, the feeding speed Vft of the welding wire 12 is changed on the sinusoidal change curve Xa to periodically generate the short-circuit period Ts and the arc period Ta.

  The feeding speed Vft of the welding wire 12 is set by superimposing a frequency component Va of the feeding speed on a constant positive feeding speed Vf1. In the positive region where the feed speed Vft is greater than zero, the feed wire 12 is forward fed. In the negative region where the feed speed Vft is less than zero, the feed wire 12 is moved backward. is there. From the middle period of the arc period Ta to the latter stage of the short circuit period Ts, the feed of the welding wire 12 is fed, and from the latter stage of the short circuit period Ts to the middle stage of the arc period Ta, the feeding of the welding wire 12 is fed back. .

  In a normal state where no change in the distance L between the tip base materials has occurred, the time for switching to the arc period Ta is approximately the same time interval when the other welding environment does not change. In this normal state, it is preferable to switch to the arc period Ta at a time when the feeding speed Vft of the welding wire 12 becomes a predetermined speed Vfa (frequency component is Va1) on the acceleration area (negative acceleration area) being reversely fed. .

  On the other hand, for example, when there is a change in the distance L between the base materials of the chip, the short-circuit period Ts immediately after time A1 in FIG. 2 is short, and the switching to the next arc period Ta is quick, or immediately after time A2 in FIG. The short-circuit period Ts is longer and the switching to the next arc period Ta is delayed.

  For example, as shown in FIG. 2, when the chip base metal distance L extends from the distance L0 to the distance Lh, the short-circuit period Ts immediately after the time A1 is short, and the switching to the next arc period Ta is quick. In such a situation, if the feeding speed Vft of the welding wire 12 is kept at the normal setting, the feeding speed Vft at the time of reverse feeding of the welding wire 12 tends to be slow.

  Further, as shown in FIG. 3, for example, when the distance between the chip base materials L decreases from the distance L0 to the distance L1, the short-circuit period Ts immediately after the time A2 is long, and the switching to the next arc period Ta is delayed. In such a situation, if the feeding speed Vft of the welding wire 12 is kept at the normal setting, the feeding speed Vft at the time of reverse feeding of the welding wire 12 tends to increase.

  Based on this, the control circuit 20 of the present embodiment first detects the average voltages Vave1, Vave2, and Vave3 of the output voltage Vw during the short circuit period Ts. That is, in the situation of FIG. 2 where the distance L between the chip base materials is increased, the average voltage of the short circuit period Ts increases from Vave1 to Vave2, for example, and in the situation of FIG. For example, the voltage drops from Vave1 to Vave3. Focusing on this, a change in the distance L between the chip base materials is detected based on detection of the average voltages Vave1 to Vave3. Incidentally, the level of the average voltages Vave1 to Vave3 can be detected by comparison with the immediately preceding one or comparison with a predetermined one. Then, the control circuit 20 determines a welding environment change such as a change in the distance L between the tip base materials from the detection of the voltage values of the average voltages Vave1 to Vave3, and sets the feeding speed Vft of the welding wire 12 suitable for the situation at that time. adjust.

Next, the operation (action) of this embodiment will be described.
“No change in the distance L between chip base materials”
When the average voltage of the output voltage Vw in the short-circuit period Ts is Vave1 within an allowable range, the synchronization deviation determination unit 20d of the control circuit 20 does not substantially change the tip base material distance L, and the current welding wire 12 It is determined that the feeding speed Vft is appropriate (synchronized), and the feeding control unit 20c maintains the change mode (change curve Xa) of the feeding speed Vft of the welding wire 12.

“When the distance L between the base materials is extended”
As shown in FIG. 2, when the average voltage of the output voltage Vw in the short-circuit period Ts exceeds the allowable range, for example, rises from Vave1 to Vave2, the synchronization deviation determination unit 20d increases the distance L between the tip base materials and increases the welding wire 12 It is determined that the feed speed Vft at the time of reverse feed is slow, and the feed control unit 20c advances the phase of the change curve Xa of the feed speed Vft of the welding wire 12 by α1 at the time of reverse feed. That is, the change speed Xa at which the normal speed when switching to the arc period Ta through the short-circuit period Ts, for example, the feed speed Vft of the welding wire 12 in the case of FIG. The phase is advanced by α1 to the top. Accordingly, when the distance L between the tip base materials is increased, the feeding speed Vft of the welding wire 12 tends to be slow. However, after the arc period Ta in which the phase is advanced during the reverse feeding, the feeding speed of the welding wire 12 is increased. The speed Vft is accelerated and the switching from the reverse feed to the forward feed is accelerated, so that the feed speed Vfa of the welding wire 12 quickly approximates the desired speed (acceleration control).

  Further, the feeding control unit 20c only performs the above-described phase adjustment at one place immediately after the change in the chip base material distance L, and does not perform the phase adjustment if there is no change in the distance L thereafter. When the distance L changes again after the phase adjustment, the above phase adjustment is performed immediately after the change. That is, the phase adjustment is performed at one place immediately after the change of the distance L once.

  Thus, in the situation where the distance L between the tip base materials is extended, the above-described phase adjustment of the feeding speed Vft when the welding wire 12 is reversely fed results in that the protruding length of the welding wire 12 from the feeding tip 13a is the distance L. The length of the wire 12 is increased and the distance between the tip of the wire 12 and the workpiece (base material) M is adjusted to be substantially maintained.

“When the distance L between chip base materials is shortened”
As shown in FIG. 3, when the average voltage of the output voltage Vw in the short-circuit period Ts exceeds the allowable range, for example, decreases from Vave1 to Vave3, the synchronization deviation determination unit 20d reduces the distance L between the tip base materials and reduces the welding wire 12 It is determined that the feeding speed Vft is fast, and the feeding control unit 20c delays the phase of the change curve Xa of the feeding speed Vft of the welding wire 12 by α2 during reverse feeding. That is, a change curve in which the normal speed when switching to the arc period Ta through the short-circuit period Ts, for example, the feed speed Vft of the welding wire 12 in the case of FIG. The phase is delayed by α2 up to Xa. Accordingly, when the distance between the tip base metals L is shortened, the feeding speed Vft of the welding wire 12 tends to increase. However, after the arc period Ta whose phase is delayed during reverse feeding, the feeding speed of the welding wire 12 is changed. The speed Vft is decelerated and the switching from the reverse feed to the forward feed is delayed, so that the feed speed Vfa of the welding wire 12 quickly approximates the desired speed (deceleration control).

  Similarly to the case where the distance between the tip base materials L is increased, the feeding control unit 20c only performs the above-described phase adjustment at one place immediately after the change in the distance L, and if there is no change in the distance L thereafter. Do not adjust the phase. That is, even when the distance between the chip base materials L is shortened, the phase adjustment is performed at one place immediately after the change of the distance L once.

  Thus, even in a situation where the distance L between the tip base materials is shortened, as a result of the above phase adjustment of the feeding speed Vft of the welding wire 12, the protruding length of the welding wire 12 from the power feeding tip 13a is shortened by the distance L. The distance between the tip end of the wire 12 and the workpiece (base material) M is adjusted to be substantially maintained.

Next, characteristic effects of the present embodiment will be described.
(1) As feeding control of the welding wire 12, the feeding speed Vft of the welding wire 12 is periodically changed so as to switch to the arc period Ta in the vicinity of switching from normal feeding to reverse feeding of the welding wire 12, The feed speed Vft of the welding wire 12 is adjusted during the reverse feed period. Then, when the feed speed synchronization deviation is determined to indicate that the feed speed Vft of the welding wire 12 is slow, acceleration control including acceleration in the reverse feed direction is performed (FIG. 2), and the feed speed Vft of the welding wire 12 is performed. When it is determined that the feeding speed synchronization deviation is high, deceleration control including deceleration in the reverse feeding direction is performed (FIG. 3). That is, a change in the welding environment such as a change in the distance between the power supply tip 13a of the welding torch 13 and the workpiece M (distance L between the tip base materials) changes the average voltage (Vave1˜) of the output voltage Vw during the short-circuit period Ts. Vave3), and when the feed speed Vft of the welding wire 12 becomes slow in relation to the average voltage, the feed speed Vft of the welding wire 12 is accelerated as acceleration control in the reverse feed period. When the feed speed Vft of the welding wire 12 becomes fast, the feed speed Vft of the welding wire 12 is decelerated as deceleration control during the reverse feed period, so that the desired speed can be quickly approximated in each situation. Therefore, arc welding can be performed satisfactorily.

  The adjustment of the feeding speed Vft of the welding wire 12 with respect to the change in the distance L between the tip base materials has been mainly described. However, the adjustment of the feeding speed Vft of the welding wire 12 with respect to changes in the welding environment other than the distance L between the tip base materials. Is also done.

  (2) Determination of whether or not the synchronization of the feeding speed Vft of the welding wire 12 has occurred is performed based on the average voltage (Vave1 to Vave3) of the output voltage Vw during the short circuit period Ts. That is, it is possible to easily determine the synchronization deviation of the feeding speed Vft of the welding wire 12 with the average voltage (Vave1 to Vave3) of the output voltage Vw.

  Further, in the present embodiment, since the feed voltage Vft of the welding wire 12 is adjusted when switching to the arc period Ta immediately after the determination based on the average voltage of the short-circuit period Ts immediately before, the feed speed Vft is reached. Reflection is prompt.

  (3) Feed control for changing the feed speed Vft of the welding wire 12 along the periodic change curve Xa is performed, and at the time of acceleration control when the feed speed Vft of the welding wire 12 is slow, the feed is performed. The phase of the change curve Xa is advanced by α1 in the reverse feed period until the speed reaches the predetermined speed Vfa at the time of speed adjustment (when switching to the arc period Ta). Further, at the time of deceleration control when the feed speed Vft of the welding wire 12 is high, the phase of the change curve Xa is reversed until the feed speed is adjusted to the predetermined speed Vfa at the time of adjustment of the feed speed (when switching to the arc period Ta). Is delayed by α2. That is, since the control is based on the phase adjustment of the periodic change curve Xa for setting the feeding speed Vft of the welding wire 12 each time, it contributes to simplification of the feeding control of the welding wire 12.

(Second Embodiment)
A second embodiment of the arc welding power supply device and the arc welding power supply control method will be described below.

  In the present embodiment, the control mode of the feed control unit 20c of the control circuit 20 is different from that of the first embodiment. In the first embodiment, the phase adjustment (amplitude is fixed) of the change curve Xa of the feeding speed Vft of the welding wire 12 is performed. In the present embodiment, the change curve Xa of the feeding speed Vft of the welding wire 12 is adjusted. This is a control mode for performing amplitude adjustment (phase fixing).

“When the distance L between the base materials is extended”
As shown in FIG. 4, when the average voltage of the output voltage Vw in the short-circuit period Ts exceeds the allowable range, for example, rises from Vave1 to Vave2, the synchronization deviation determination unit 20d increases the distance L between the tip base materials and increases the welding wire 12 It is determined that the feeding speed Vft is slow, and the feeding control unit 20c reduces the amplitude of the change curve Xa of the feeding speed Vft of the welding wire 12 during reverse feeding when switching to the arc period Ta after this short-circuit period Ts. . Accordingly, when the distance L between the tip base materials is extended, the feeding speed Vft of the welding wire 12 tends to be slow, but the feeding speed Vfa of the welding wire 12 is used by using the change curve Xb having a small amplitude at the time of reverse feeding. Is quickly approximated to the desired speed (acceleration control).

  For example, in the case of FIG. 4, the feeding control unit 20 c changes the feeding speed Vft of the welding wire 12 on a change curve Xb having a small amplitude from a predetermined speed Vfa on the deceleration area during reverse feeding to the feeding speed Vf1. After that, it is changed on the normal change curve Xa. That is, also in this amplitude adjustment, the amplitude adjustment is performed at one place immediately after the change of the distance L once.

  Thus, in a situation where the distance L between the tip base materials is extended, by adjusting the amplitude of the feeding speed Vft of the welding wire 12 at the time of reverse feeding, as a result, the protruding length of the welding wire 12 from the power feeding tip 13a becomes the distance L. Therefore, the distance between the tip of the wire 12 and the workpiece (base material) M is substantially maintained.

“When the distance L between chip base materials is shortened”
As shown in FIG. 5, when the average voltage of the output voltage Vw in the short-circuit period Ts exceeds the allowable range, for example, decreases from Vave1 to Vave3, the synchronization deviation determination unit 20d reduces the distance L between the tip base materials and reduces the welding wire 12 It is determined that the feeding speed Vft is fast, and the feeding control unit 20c increases the amplitude of the change curve Xa of the feeding speed Vft of the welding wire 12 at the time of reverse feeding when switching to the arc period Ta after this short-circuit period Ts. . Accordingly, when the distance L between the tip base materials is shortened, the feeding speed Vft of the welding wire 12 tends to increase, but the feeding speed Vfa of the welding wire 12 can be obtained by using the change curve Xc having a large amplitude during reverse feeding. Is quickly approximated to the desired speed (deceleration control).

  Further, for example, in the case of FIG. 5, the feeding control unit 20c changes the feeding speed Vft of the welding wire 12 on a change curve Xc having a large amplitude from a predetermined speed Vfa on the acceleration region being reversely fed to the feeding speed Vf1. After that, it is changed on the normal change curve Xa. That is, also in this amplitude adjustment, the amplitude adjustment is performed at one place immediately after the change of the distance L once.

  Even in the situation where the distance L between the tip base materials is reduced as described above, the above-mentioned amplitude adjustment of the feeding speed Vft of the welding wire 12 at the time of reverse feeding results in that the protruding length of the welding wire 12 from the feeding tip 13a is a distance. The length of the wire 12 is shortened and the distance between the tip of the wire 12 and the workpiece (base material) M is substantially maintained.

Next, characteristic effects of the present embodiment will be described.
(1) (2) In the second embodiment, the same effects as the effects (1) and (2) of the first embodiment can be obtained.

  (3) At the time of acceleration control in a situation where the feed speed Vft of the welding wire 12 is slow, the amplitude of the change curve Xa is reduced in the reverse feed period using the change curve Xb having a small amplitude. Further, at the time of deceleration control when the feeding speed Vft of the welding wire 12 is fast, the amplitude of the change curve Xa is increased in the reverse feed period using the change curve Xc having a large amplitude. That is, since the control is based on the amplitude adjustment of the periodic change curve Xa for setting the feeding speed Vft of the welding wire 12 each time, it contributes to simplification of the feeding control of the welding wire.

In addition, you may change the said embodiment as follows.
The average deviation of the output voltage Vw during the short circuit period Ts was used to determine the synchronization deviation of the feeding speed Vft of the welding wire 12 due to the welding environment change such as the change in the distance L between the tip base materials. A voltage value other than the average voltage of Vw may be used. Moreover, not only the voltage value in one short circuit period Ts but the voltage value in several short circuit periods Ts may be used. The output current Iw may be used. Alternatively, the determination may be made using a time lag between the scheduled time and the actual time. Further, the feeding speed synchronization deviation may be determined using one or more other parameters such as direct measurement of the distance L between the chip base materials by a distance measuring device.

-Although the feed speed Vft of the welding wire 12 was adjusted at the time of switching to the arc period Ta, it may be performed at other timings in the reverse feed period.
-In addition, you may change suitably the structure of the arc welding machine 10, the power supply apparatus 11 for arc welding, and the control circuit 20. FIG.

In addition, various controls related to arc welding such as control of the feeding speed Vft of the welding wire 12 may be changed as appropriate.
Next, a technical idea that can be grasped from the above embodiment and another example will be added below.

  (B) A welding torch for feeding and holding the welding wire, a feeding device for feeding the welding wire and controlling the feeding operation, and any one of claims 1 to 4. An arc welding machine comprising a power supply device for arc welding.

  According to this structure, it can provide as an arc welding machine which controls the feeding speed of a welding wire appropriately, and performs arc welding favorably.

DESCRIPTION OF SYMBOLS 11 Power supply apparatus for arc welding 12 Welding wire 20a Output control part 20c Feed control part 20d Synchronous deviation determination part M Workpiece Ts Short-circuit period Ta Arc period Iw Output current (output power)
Vw output voltage (output power)
Vave1, Vave2, Vave3 Average voltage Vft Feeding speed Vfa Predetermined speed Xa, Xb, Xc Change curve α1, α2 Phase

Claims (5)

Output control that adjusts to the output power suitable for each period of the short circuit period and arc period for arc welding in order to generate arc at the tip of the electrode with welding wire as discharge electrode and to perform arc welding of the work to be welded In addition to the wear of the welding wire due to the arc, the feeding speed including the forward and reverse feeding of the welding wire is periodically changed so as to generate a periodic change between a short circuit period and an arc period for arc welding. A power supply device for arc welding comprising a feed control unit,
A synchronization deviation determination unit that determines a feeding speed synchronization deviation of the welding wire for each period;
The feeding control unit periodically changes the feeding speed of the welding wire so as to switch to the arc period in the vicinity of the switching from the normal feeding to the reverse feeding of the welding wire, and the welding wire is switched during the reverse feeding period. The wire feeding speed is adjusted, and when the synchronization deviation judging unit judges that the feeding wire synchronization speed is slow, the acceleration including the acceleration in the reverse feeding direction is performed. Control is performed, and when the determination of the feeding speed synchronization deviation that the feeding speed of the welding wire is fast is made in the synchronization deviation determination unit, deceleration control including deceleration in the reverse feeding direction is performed. Power supply device for arc welding. In the power supply apparatus for arc welding according to claim 1,
The power supply apparatus for arc welding, wherein the synchronization deviation determination unit determines that a feed speed synchronization deviation of the welding wire has occurred based on detection of an output voltage during the short circuit period. In the power supply apparatus for arc welding according to claim 1 or 2,
The feed control unit is configured to change the feed speed of the welding wire along a periodic change curve, and at the time of the acceleration control, the feed rate of the change curve is changed to a predetermined speed at the time of adjusting the feed speed. Control is performed to advance the phase in the reverse feed period, and during the deceleration control, control is performed to delay the phase of the change curve in the reverse feed period until it reaches a predetermined speed at the time of adjustment of the feed speed. Power supply for arc welding. In the power supply apparatus for arc welding according to claim 1 or 2,
The feeding control unit is configured to change the feeding speed of the welding wire along a periodic change curve. During the acceleration control, the amplitude of the change curve is changed using a change curve having a small amplitude. The arc welding power source apparatus is characterized in that control is performed to reduce the amplitude of the change curve, and during the deceleration control, control is performed to increase the amplitude of the change curve in a reverse feed period using a change curve having a large amplitude. Output control that adjusts to the output power suitable for each period of the short circuit period and arc period for arc welding in order to generate arc at the tip of the electrode with welding wire as discharge electrode and to perform arc welding of the work to be welded And feeding that periodically changes the feeding speed including forward and reverse feeding of the welding wire in order to generate a periodic change between a short-circuit period and an arc period of arc welding in addition to the consumption of the welding wire by the arc. A control method of a power supply device for arc welding that performs control,
The feeding speed of the welding wire is periodically changed so as to switch to the arc period in the vicinity of switching from normal feeding to reverse feeding of the welding wire, and adjustment of the feeding speed of the welding wire is performed in the reverse feeding period. Is what
A synchronization deviation determination is performed to determine the welding wire feeding speed synchronization deviation with respect to each period, and when a feeding speed synchronization deviation is determined to indicate that the welding wire feeding speed is slow, acceleration in the reverse feeding direction is performed. An arc welding power source characterized in that the acceleration control including the deceleration is performed and the deceleration control including the deceleration in the reverse feeding direction is performed when the determination of the feeding speed synchronization deviation indicating that the feeding speed of the welding wire is high is made. Control method of the device.