JPH091332A - Consumable wire type pulse arc welding machine - Google Patents

Abstract

PURPOSE: To provide a consumable wire type pulse arc welding machine capable of stabilizing the arc length between the wire tip part and a work, and favorable to improve the welding quality. CONSTITUTION: A wire tip part Al in a pulsatingly feeding device 30 is held by feeding resistance pieces 320, 321 while a wire A is fed at the constant speed by a feeding roller 14, and the speed of the wire tip part A1 is reduced by the friction. The wire tip part A1 is deflected, and the wire is accumulated in the pulsatingly feeding device 30. When the feeding resistance pieces 320, 321 are returned to the original position, the deflection of the wire tip part A1 is released, and the wire tip part A1 is pulsatingly fed toward a work 11. The pulsating feeding is achieved in a synchronous manner with or at the prescribed phase difference to the pulse current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire-consumable pulse arc welding machine for welding by melting an end portion of a wire with an arc generating current including a pulse current.

[0002]

2. Description of the Related Art Conventionally, wire-consumable pulse arc welders have been used in the industrial world. According to this wire-consumable pulse arc welding machine, an arc generating current including a pulse current is supplied to the wire in a state where the wire tip is brought close to the work piece, whereby the wire tip part and the work piece are welded. An arc is generated between them, and the heat of the arc melts the tip of the wire for welding.

Although it depends on the type of wire-consumable pulse arc welding machine, the period of the pulse current is generally 5 [ms] or more.
20 [ms], and the pulse current supply time is 1 to 3
[Ms]. In this wire consumption type pulse arc welding machine, since a droplet is basically generated from the wire tip portion for each pulse current, the wire tip portion is consumed. When the droplets separate from the tip of the wire, the distance between the tip of the wire and the object to be welded tends to increase.

In order to maintain the welding quality in this wire-consuming pulse arc welding machine, it is preferable that the distance between the tip of the wire and the object to be welded does not fluctuate as much as possible in order to maintain the arc length. That is, when the distance between the tip of the wire and the object to be welded increases, the arc becomes unstable and sufficient penetration cannot be expected. Further, when the distance between the wire tip portion and the object to be welded is narrowed, the wire tip portion and the object to be welded are likely to be short-circuited and spatter is easily generated.

Therefore, in Japanese Patent Publication No. 62-50221, attention is paid to the fact that the arc voltage corresponds to the distance between the tip of the wire and the workpiece, and the arc voltage during welding is detected and detected. The arc voltage value and the target arc voltage value are compared, and the arc voltage is maintained at a constant value based on the difference signal, which quickly corrects the gap between the wire tip and the workpiece to make it constant. Techniques for maintaining it are disclosed.

Further, in recent years, as a conventional technique, a variable controller for controlling the speed of the feed motor is provided in order to make the feed speed of the feed motor for feeding the wire variable, and the droplet at the tip of the wire is Immediately after separating from the wire tip and moving to the work piece and increasing the gap between the wire tip and the work piece, the variable control device increases the speed of the feed motor for a predetermined time (several ms). Therefore, the present applicant has a technique for pulsing the wire tip toward the object to be welded, thereby quickly correcting the distance between the wire tip and the object to be welded to maintain it constant. It has been disclosed (JP-A-6-142).
927 publication).

FIG. 11 shows a timing chart of the technique disclosed in Japanese Patent Laid-Open No. 6-142927. FIG.
(A) shows the tip B of the wire from the contact tip 10r
The arc C is generated based on the arc generating current supplied to the wire No. 1, and the heat of the arc C causes the droplet B2 to be generated from the wire tip portion B1 and the droplet B2 is separated from the wire tip portion B1 to be welded. 11 schematically shows a temporal change in the state of shifting to 11. FIG. 11B shows a timing chart of the arc generation current used for welding. FIG. 11C shows a timing chart of the speed of the wire tip portion B1.

According to the wire consuming pulse arc welding described above, the pulse current I _P is periodically superimposed on the base current I _B as shown in FIG. 11 (B). Here, although the pulse current droplet B2 of I _P rise immediately before time t1 in the wire B is very small, droplet B2 growth at time t2, t3 in the wire tip B1 of the pulse current I _P is up doing. At times t4 and t5, the pulse current I _P has fallen, and the droplet B2 has separated from the wire tip portion B1.

According to the technique disclosed in FIG. 11, at the times t4 and t5 immediately after the droplet B2 has separated,
The velocity of the wire tip portion B1 increases from Va to Vb with a predetermined phase difference ΔTa with respect to the pulse current I _P , whereby the wire tip portion B1 is pulsed toward the workpiece 11. Therefore, even if the distance Lc between the object to be welded 11 and the wire tip portion B1 increases as the droplet B2 separates, the distance Lc can be promptly corrected by pulsation, which contributes to improvement in welding quality.

Further, the above-mentioned Japanese Patent Laid-Open No. 6-142927 discloses a technique relating to the timing charts shown in FIGS. 12 (A) (B) (C). According to the timing chart shown in FIG. 12, in synchronization with the pulse current I _P , the speed of the wire tip portion B1 is increased, the wire tip portion B1 is pulsed, and the feed amount of the wire tip portion B1 is increased. doing.

Here, the pulse current I in which the current rapidly increases
_{When P} is fed, the contact tip 10r easily has heat due to Joule heat. However, as shown in FIG. 12, if the feed amount of the wire tip portion B1 is increased in synchronization with the pulse current I _P , the heat of the contact tip 10r is transferred to the wire tip portion B1.
It becomes easy to transfer heat to the 1st side, so contact tip 10r
Contact chip 10 caused by overheating of the
It can contribute to reduce the thermal damage of r.

[0012]

By the way, according to the technique disclosed in Japanese Unexamined Patent Publication No. 6-142927 mentioned above, the tip portion B1 of the wire is synchronized with the pulse current I _P with a predetermined phase difference or as described above. The method of pulsing is adopted. According to the technique disclosed in this publication, when the wire tip portion B1 is pulsed, a variable control device for varying the rotation speed of the feed motor for feeding the wire must be provided. In this case, the device is likely to be complicated and the price is increased.

According to another technique disclosed in the above, that is, the technique disclosed in Japanese Patent Publication No. 62-50221, a method based on an arc voltage is adopted to maintain the distance between the wire tip and the object to be welded. ing. The present invention adopts a method different from the above-mentioned two publication techniques, and by switching between the first mode in which the wire length is accumulated and the second mode in which the accumulated amount is canceled or reduced, With the switching from the form to the second form, the speed of the wire tip portion is increased to pulsate the wire tip portion toward the object to be welded, thereby maintaining the interval between the wire tip portion and the object to be welded, and arcing. An object of the present invention is to provide a wire-consumable pulse arc that is advantageous for stabilizing the length and improving the welding quality.

[0014]

A wire consumable pulse arc welding machine according to the present invention has a wire feeding means for feeding a wire, and a wire feeding means for feeding a wire tip toward a workpiece. A first form for accumulating wire length in at least a part of the wire, and a power supply means for generating an arc between the wire and the object to be welded by the arc-generating current including a pulse current, which causes the wire tip to be melted and consumed And a second mode for releasing or reducing the accumulated amount of the wire tip. The wire tip is synchronized with the pulse current or with a predetermined phase difference when switching from the first mode to the second mode. And a pulsing means for pulsating the portion to the object to be welded.

[0015]

According to the wire-consumable pulse arc welding machine of the present invention, when the wire feeding means is operated, the wire is conveyed by the feeding portion and the tip end of the wire is directed to the object to be welded.
The feeding unit preferably feeds the wire toward the object to be welded at a substantially constant speed, but the feeding unit is not necessarily limited to this, and in short, it can feed the tip of the wire to the object to be welded. Good.

[0016] Due to the arc generation current including the pulse current,
An arc occurs between the wire tip and the work piece. The tip of the wire is melted by the heat of the arc. Therefore, the wire is consumed, and the melted portion such as droplets is separated from the tip of the wire and transferred to the object to be welded to perform welding. When the melted portion such as a droplet is separated from the tip of the object to be welded and transferred to the object to be welded, the distance between the tip of the wire and the object to be welded increases as in the conventional technique. Instability of the arc when increasing,
Welding problems such as undercut are likely to be induced.

In this respect, according to the wire-consumable pulse arc welding machine of the present invention, the pulsating means is the first for accumulating the wire length.
It is possible to switch between the form and the second form that releases or reduces the accumulated amount. The wire length is accumulated in the first form of the pulsating means. When the pulsing means is switched from the first mode to the second mode, the accumulated amount of wire length is released or reduced, so that the speed of the wire tip portion increases, and the wire tip portion pulsates toward the workpiece. To be done. This suppresses an excessive increase in the distance between the wire tip and the object to be welded.

The pulsating means according to the present invention has a first mode in which a wire feeding resistance is applied to the wire to accumulate the wire length, and a wire feeding resistance is released or reduced to release or reduce the wire length accumulation. It can be configured with a feed resistance switching unit that can be switched to the second mode. The pulsating means according to the present invention includes a first mode in which a wire is bent at a predetermined curvature to accumulate the wire length, and a second mode in which the wire flexure is released or reduced to release or reduce the wire length accumulation. And a wire bending switching portion that can be switched to and.

Further, the pulsating means according to the present invention has a first mode in which the total length of the wire feeding path is increased by a minute amount (ΔLf) to accumulate the wire length, and a second embodiment in which the total length of the wire feeding path is restored. It can be configured by a wire feed path length switching unit that can be switched to any shape.

[0020]

Embodiment 1 Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS. First, the overall configuration according to this embodiment will be described. FIG. 1 shows an overall configuration diagram of an embodiment of a wire consumption type pulse arc welding machine according to the present invention. In FIG. 1, reference numeral 1a indicates a power supply means, and reference numeral 1 indicates a primary side input rectifier circuit. The output terminal of the rectifier circuit 1 is connected to the smoothing circuit 2 and then to the inverter circuit 3.

The output terminal of the inverter circuit 3 is connected to the high frequency transformer 4. The high frequency transformer 4 is connected to the rectifier circuit 5, and the positive electrode of the output terminals of the rectifier circuit 5 functions as a power feeder inside the torch 10 via the power cable 8 having the reactor 6.
It is connected to 0r. The negative electrode of the rectifier circuit 5 is a welded object 1 made of metal, which is an object to be welded via the power cable 9.
1 connected. The torch 10 is disposed close to and above the object to be welded 11, and the torch tip portion 10f faces the portion to be welded of the object to be welded 11 at a predetermined distance.

The wire feeding means 12 continuously feeds the consumable wire A (diameter: 1.2 mm) functioning as a welding rod toward the object 11 to be welded at a substantially constant speed (V _W ). Is. The wire feeding means 12 includes a wire reel 13 on which the wires A are wound in a multiple manner, a pair of feeding rollers 14 as a feeding portion, and a feeding motor 15 that rotationally drives the feeding roller 14 in the direction of arrow P1. It consists of and.

An output terminal of a motor control unit 17 is connected to the feed motor 15, and the feed motor 15 and thus the feed roller 14 are controlled by the motor control unit 17. That is, the feeding speed of the wire A is determined by the command value of the motor control unit 17. Therefore, when the feeding motor 15 is driven, the pair of feeding rollers 14 rotate in the arrow P1 direction, whereby the wire A is fed in the arrow H1 direction at a substantially constant speed. The wire A of the wire reel 13 is inserted into the torch 10 via the flexible wire conduit 16 having flexibility, is inserted into the tip hole of the contact tip 10r, and is fed toward the workpiece 11. This wire A has conductivity, and in the torch 10 the contact tip 10r
Is in electrical contact with. Therefore, the wire A is fed from the contact tip 10r via the power cable 8.

The above construction is similar to that of the conventional pulse welding machine. That is, the three-phase alternating current supplied to the primary side is rectified by the rectifying circuit 1 to become a direct current, then smoothed by the smoothing circuit 2 to reduce ripples, and then supplied to the inverter circuit 3 as a direct current power supply. The inverter circuit 3 outputs a signal of a desired cycle to the high frequency transformer 4 based on the drive signal supplied from the power element drive circuit 27.

Then, the current output from the inverter circuit 3 is transformed by the high frequency transformer 4 and rectified again by the rectifying circuit 5, and then the DC base current I _B and the desired pulse current I _P are superimposed. And the wire A is fed in that form. Therefore, in the present embodiment, the arc C formed between the wire A and the workpiece 11 is the DC base current I _B and the desired pulse current I _P as in the prior art.
It has an arc generating current in a state where and are superposed. At this time, the wire tip portion A1 is melted by the heat of the arc C as in the conventional case, and is separated from the wire tip portion A1 as a droplet to be transferred to the object to be welded 11. Although the wire A is consumed by the melting, the supply motor 15 and thus the supply roller 14 are continuously rotated at a predetermined speed by the motor controller 17, so that the consumption of the wire A due to the detachment of the droplets is replenished. Is done.

In the present embodiment, the current value and voltage value of the arc C formed between the wire A and the object 11 to be welded are feedback-controlled, so that if a stable arc C can be secured. It is tight. The feedback system of this embodiment will be described below. In FIG. 1, reference numeral 20 indicates an average voltage detector. The average voltage detector 20 detects the potential difference between the power cables 8 and 9 and supplies the detected value to the voltage comparator 21. In addition to the average voltage detector 20 described above, the voltage comparator 21 includes a power cable 8,
The output terminal of the average voltage setting unit 22 for setting a predetermined target potential value to be generated between 9 is connected. Then, the voltage comparator 21 compares these values and outputs the voltage command to the current waveform setting unit 23 in order to bring the measured value closer to the target potential value.
Output to

The potential difference generated between the power cables 8 and 9 has a value corresponding to the distance Le between the wire tip portion A1 of the wire A and the object 11 to be welded. If this value can be kept constant, the length of the arc C can be kept almost constant, and the welding quality will be stable. Therefore, when it is detected that the potential difference generated between the power cables 8 and 9 is lower than the target voltage value, that is, when the distance Le between the wire A and the workpiece 11 is narrowed, the current waveform setting unit. 23
Then, the arc current value is increased to accelerate the wear of the wire A. In the opposite case, that is, when the potential value is detected to be higher than the target voltage value, that is, the wire A
When the distance Le between the welding target 11 and the workpiece 11 increases,
The arc current is reduced in order to suppress the wear of the wire tip portion A1.

A current detector 25 is connected to the shunt 7 of the power cable 8. The current detector 25 detects the value of the arc current between the wire A and the workpiece 11 and outputs the detected value to the comparator 26. The comparator 26 compares the current value supplied from the current detector 25 with the current waveform of the current waveform setting unit 23, and outputs the comparison result to the power element drive circuit 27.

Based on the comparison result of the comparator 26, the power element drive circuit 27 uses an inverter so that the arc current flowing from the wire A toward the workpiece 11 corresponds to the current set by the current waveform setting section 23. The circuit 3 is driven to control the current flowing through the power cables 8 and 9.
Now, a configuration of a main part according to the present embodiment will be described. In this embodiment, as shown in FIG. 1, a pulsation device 30 for pulsating the wire tip portion A1 and a pulsation control unit 31 for controlling the operation of the pulsation device 30 are provided. The pulsation device 30 and the pulsation control unit 31 constitute pulsation means. The pulsation device 30 is mounted on the torch 10.

The pulsation control unit 31 outputs a command signal for controlling the pulsation operation of the pulsation device 30 to the pulsation device 30 via the signal line 31a, and at the same time, outputs a signal synchronized with this command signal via the signal line 31b. And outputs it to the pulse phase setting unit 32. The pulse phase setting unit 32 sets the target phase of the rising of the pulse current I _{P in} order to cope with the height variation of the wire tip portion A1, and outputs the current rising command signal to the current waveform setting unit 23.

The main part of the pulse delivery device 30 according to this embodiment is shown in FIG.
(A) and (B). As shown in FIGS. 2A and 2B, the pulsation device 30 includes a guide passage 3 through which the wire A passes.
00, a feed resistor 320, 321 disposed on the guide member 310 so as to be displaceable in a direction intersecting the extending direction of the wire A, and a feed resistor 320, 32.
It is provided with drive circuits 330 and 331 for driving 1.

In the guide passage 300, flexible accommodating spaces 301 and 302 for accumulating the length of the wire A are formed.
The feeding resistors 320 and 312 use the expansion / contraction function of the piezoelectric element, the excitation function of the electromagnetic solenoid, the cylinder that reciprocates with a fluid such as air or hydraulic oil, or magnetostriction in some cases. It can be configured by using an element. The piezoelectric element may be a laminated type in which a large number of piezoelectric substances such as PZT are laminated, or a bimorph type. In this case, it is also preferable to provide an enlarging mechanism for enlarging the physical displacement amount of the piezoelectric element in order to secure the physical displacement amount. Use of a piezoelectric element is advantageous for high-speed response and downsizing.

The tip portions 3 of the feeding resistors 320, 321
The tips of 20n and 321n are projected to reduce the contact area with the wire A. Also, the tips 320n, 32
It is also preferable that 1n is formed of a member having a large frictional resistance. In the present embodiment, the drive circuits 330 and 331 are activated by the command signal from the pulsation control unit 31, and the feeding resistor 32 is operated.
0 and 321 are switched to the first form. Then, the feeding resistors 320 and 321 are displaced in the arrow X1 direction in FIG. Therefore, the wire A in the guide passage 300 is fed by the feeding resistor 320,
The wire A is sandwiched by 321 and the frictional resistance of the wire A increases, and the feeding speed of the wire tip portion A1 decreases or becomes zero. On the other hand, the wire A is continuously fed by the feed roller 14 toward the workpiece 11 in the direction of the arrow H1 at a substantially constant speed (V _W ).

Therefore, as can be understood from FIG. 2 (B),
First wire A is sandwiched between feeding resistors 320 and 321
In the configuration, the wire A in the guide passage 300 of the pulsation device 30 is
Is bent into a substantially S-shape, and the bent portion is housed in the flexure housing spaces 301 and 302. The wire length is partially accumulated due to such bending. After that, the pulse control unit 3
The drive signals 330, 331 are activated by the command signal from the switch 1 to switch the feeding resistors 320, 321 to the second mode. Then, the feeding resistors 320 and 321 return to the arrow X2 direction. Therefore, the sandwiching of the wire A by the feeding resistors 320 and 321 is released, and the wire A and the feeding resistor 320,
Friction resistance with 321 is eliminated.

Therefore, the flexible accommodation space 3 of the pulsating device 30
The bent portion of the wire A, which has been bent in the substantially S shape at 01 and 302, is released. For example, as shown in FIG. 2 (A), the elastic force of the wire A returns to a substantially straight state. When the accumulation of the wire length is released in this manner, the guide member 310
From the discharge port 301 at the lower end of the wire, the wire tip portion A1 is rapidly discharged by its elastic force or the like. That is, the speed of the wire tip portion A1 rapidly increases, and the wire tip portion A1 is pulsed toward the workpiece 11.

The arrow X1 of the feeding resistors 320 and 321
The amount of movement in the direction is appropriately changed depending on the conditions of the wire-consumable pulse arc welding, but in general, it is 0.05-
It can be about 0.3 mm, especially about 0.1 to 0.2 mm. The pulsation amount of the wire tip portion A1 is appropriately changed depending on the conditions of the wire-consumable pulse arc welding, but can be generally about 0.3 to 2 mm, particularly about 0.5 to 0.8 mm.

As shown in FIG. 2, an inclined surface 301r is formed on the downstream side of the flexible accommodation space 301 so as to descend downward as it goes downward. On the downstream side of the flexible accommodating space 302, an inclined surface 30 that descends and inclines downward
2r is formed. Therefore, the bent wire A
It is advantageous for elastic recovery. According to the present embodiment, based on the command signal from the pulsation control unit 31, the wire length accumulation operation (that is, the first mode) due to the bending of the wire A described above, and further the accumulation cancellation operation (that is, the second mode) are performed. The output of the pulse current I _P is periodically performed with a predetermined phase difference.

FIG. 3 shows a time chart for explaining the state of the wire tip portion A1 when the wire A is fed at a constant speed (V _W ). (A) to FIG.
(E) shows a temporal change of the wire tip portion A1. FIG.
(B) shows the fluctuation of the arc current. FIG. 3C shows the fluctuation of the speed of the wire tip portion A1. The appearance of the droplet A2 is shown in (A) to (E) of FIG. As can be seen from FIG. 3 (A) (d), the droplet A2
When is separated from the wire tip portion A1, the distance Le between the wire tip portion A1 and the workpiece 11 is increased.

As can be understood from FIG. 3B, the "rising" of the pulse current I _P is indicated by I _Pr (rising), and the "falling" is indicated by I _Pf (falling). At time t1 before the rise I _Pr of the pulse current I _P , the droplet A2 of the wire tip A1 is minute. Large pulse current value current I _P is the wire tip A1
This is because there is no power supplied to.

[0040] In addition the time t2, t3 of the pulse current I _P is up, droplet A2 by melt by the pulse current I _P is growing. Further, times t4 and t5 are times after the rising edge I _Pf of the pulse current I _P , and
4, the droplet A2 has separated from the wire tip A1.
At time t5, the droplet A2 has finished transferring to the object 11 to be welded. Note that it is generally considered that the detachment of the droplet A2 also affects the fact that the melted portion is narrowed down by the influence of the magnetic field due to the rapid pulse current I _P and the electromagnetic force based on the magnetic field.

In this embodiment, as can be understood from FIG. 3, the speed of the wire tip portion A1 reaches the maximum value V _m after a delay of a predetermined phase difference with respect to the falling edge I _Pf of the pulse current I _P. This indicates that the wire tip portion A1 was pulsed. Therefore, as can be understood from the comparison between (e) and (e) in FIG. 3B, the distance Le between the wire tip portion A1 and the object 11 to be welded is rapidly returned to the original size by pulsation. It has been corrected.

According to the present embodiment, as can be understood from FIG. 3 (C), the time at which the speed of the wire tip portion A1 begins to decrease is t1. That is, the speed of the wire tip portion A1 starts to decrease from time t1 that is ΔTc before the time of the rising edge I _Pr of the pulse current I _P , and the accumulation of the wire length is started. That is, as shown in FIG. 2B, the feeding resistors 320, 3
This is because 21 holds the wire A. Therefore, the accumulation amount of accommodating and accumulating the wire A in the flexure accommodating spaces 301 and 302 of the pulsation device 30 increases. Since the accumulated amount of the wire A is thus increased, the wire tip portion A1 can be effectively pulsed when the first mode is switched to the second mode. Of course, the pulsed amount of the wire A can be secured.

According to FIG. 3C, the wire tip portion A
The time from the time t1 when the speed of 1 starts to decrease to the maximum value V _m of the wire speed is shown as Ti. By the way, if the droplet A2 generated at the wire tip portion A1 hangs down without coming off from the wire tip portion A1 and comes into contact with the object 11 to be welded, a short-circuit phenomenon occurs and a problem such as spatter occurs, which is disadvantageous in maintaining welding quality. Is. According to the pulse arc welding as in this embodiment, a large magnetic field is generated when the pulse current I _{P in} which the current sharply increases is output,
It is considered that the droplet A2 tends to be squeezed and droop due to the influence of the electromagnetic force based on the magnetic field, and therefore the fear of a short circuit phenomenon due to the droop of the droplet A2 is even more serious.

In this respect, according to this embodiment, the wire tip portion A
When the droplet A2 generated in No. 1 is growing, as can be understood from FIG. 3C, the feeding speed of the wire tip portion A1 becomes Vh, which is lower than the value of the speed (V _W ). (Vh <V _W ). Therefore, it is advantageous to prevent the droplet A2 from landing on the object to be welded 11 without being separated from the wire tip portion A1, that is, to prevent the short-circuit phenomenon due to the droplet A2, which can contribute to elimination of problems such as spatter.

In the embodiment shown in FIG. 3, the pulse current I _P
Is output at intervals of, for example, 3 to 6 ms, and the power supply time of the pulse current I _P is, for example, 0.8 to 1.3 ms. FIG. 4 is a time chart of another embodiment according to the above embodiment. 4 (A), (A) to (E) show temporal changes in the wire tip portion A1. FIG. 4B shows the fluctuation of the arc generation current. FIG. 4C shows the fluctuation of the speed of the wire tip portion A1. As can be understood from FIG. 4 (C) According to this embodiment, the rising I _Pr of the pulse current I _P after the elapse .DELTA.Td, speed of the wire tip A1 begins to decrease, i.e. wire Nagano accumulation is started. The velocity of the wire tip portion A1 has the maximum value V _m with a predetermined phase difference with respect to the falling edge I _Pf of the pulse current I _P.

According to FIG. 4C, the time from the time when the speed of the wire tip portion A1 starts to decrease to the maximum value V _m of the wire speed is shown as Th. Here, the time Th is shorter than the time Ti (Th <Ti). Therefore, according to the timing chart shown in FIG. 4, the speed of the wire tip portion A1 does not extremely decrease during the period in which the pulse current I _P is being output. Therefore, even if the contact tip 10r has Joule heat, the heat of the contact tip 10r can be effectively transferred to the wire tip portion A1, and overheating of the contact tip 10r can be suppressed.
Therefore, it is advantageous to reduce or avoid the thermal damage and the shortening of the life of the contact tip 10r due to overheating.

According to the present embodiment, whether the timing chart shown in FIG. 3 or the timing chart shown in FIG. 4 is selected can be appropriately selected according to the conditions of pulse arc welding. In the above-described embodiment, the method of pulsating the wire tip portion A1 with a predetermined phase difference with respect to the output of the pulse current I _P is adopted, but the present invention is not limited to this.
Synchronously to the output of the pulse current I _P as shown in the timing chart of 2, that is, the bets transmission pulse of the pulse current I _P and the wire distal end portion A1 as a time the same phase, the wire tip A1 Myakuoku The method of doing may be adopted.

By synchronizing in this way, a pulse with a large current is generated.
Current I_PFeed amount of wire tip A1
Increase. Therefore, as in the previous case, a pulse current with a large current is used.
Style I _PThat the contact tip 10r has heat
Even if the heat of the contact tip 10r is transferred to the wire A
It is advantageous to do. Therefore, the contact tip 10r
It is advantageous for reducing and avoiding overheating and thermal damage caused by overheating.
You. (Other example) ○ FIG. 5 shows Example 2. The example shown in FIG.
The configuration is the same as that of the described first embodiment. Below different parts
The explanation will be centered. In this example, the pulse current I_PStanding
Climb I_PrTo the current waveform setting section 23
To detect. Then, the signal is supplied to the pulse phase setting unit 3
2 and the pulse phase setting unit 32 outputs the wire A
Set the target phase of pulsation when pulsing. And pulse
The phase setting unit 32 sends a signal related to the target phase of pulse transmission to the signal line.
It outputs to the pulsation control part 31 via 31b. Pulse control unit
31 controls the operation of the pulsating apparatus 30 via the signal line 31a
In the same manner as in the first embodiment described above,
And the second mode are switched periodically, which allows the tip of the wire
The part A1 is pulsed toward the object to be welded 11. ○ FIG. 6 shows a main part of the third embodiment. The example shown in FIG. 5 is also basic.
The configuration is similar to that of the first embodiment described above. The following is different
The part will be mainly described. In this example, the pulsation device 40
Is a guide member 410 having a guide passage 400 and a guide member
A feed resistor 420, 42 displaceably arranged at 410.
1 and a drive circuit 4 for driving the feeding resistors 420, 421
It is equipped with 30, 431. In the guide passage 400,
The flexible accommodation space 401 for accumulating the length of the yarn A is formed.
I have. The bending accommodating space 401 has a vertically elongated substantially rhombic shape.
And has inclined surfaces 401a to 401d.

The feeding resistors 420 and 421 use the expansion and contraction functions of the piezoelectric element, the excitation function of the electromagnetic solenoid, and the cylinders that reciprocate with fluid such as air and hydraulic oil as described above. It can be configured. Also in this example, the command signal from the pulsation control unit 31 is the drive circuits 430 and 43.
It is output to 1. Therefore, the driving circuit 430 drives one feeding resistor 420 in the direction of arrow X3, and at the same time, the driving circuit 431 causes the other feeding resistor 421 to move in the direction of arrow X3.
Drive in the 4'direction. Here, since the wire A is continuously fed in the direction of the arrow H1 at the constant speed (V _W ) by the feeding roller 14, the wire A accommodated in the pulsation device 40 can be understood from FIG. So that it bends to the right. The bent portion is accommodated in the flexure accommodation space 401, and the wire length is thereby accumulated.

After that, the drive circuits 430 and 431 are activated by the command signal from the pulsation control unit 31, and one of the feeding resistors 420 is driven in the direction of arrow X4, and at the same time, the other feeding resistor 421 is indicated by the arrow. Drive in X3 'direction, wire A
Bends to the left as shown by the chain line in FIG. Wire A like this
Is bending to the right or to the left while the wire A
Returns to a straight state due to its elasticity. At this time, the feeding speed of the wire tip portion A1 rapidly increases, and the pulsation device 3
0 is discharged rapidly from the discharge port 401 of the guide member 410. That is, the wire tip portion A1 is pulsed toward the workpiece 11.

In this example, the feeding resistor 420 has an arrow X3.
When the wire A moves in the direction of arrow X4 and then returns in the direction of the arrow X4, that is, when the feeding resistor 420 makes one reciprocation, the wire A is bent twice in the right side and the left side in FIG. Therefore, the number of times of bending deformation of the wire A can be increased, which is advantageous for speeding up the bending deformation of the wire A. ○ FIG. 7 shows a main part of the fourth embodiment. In this example, the pulsating device 5
0 includes a guide member 510 having a guide passage 500 through which the wire A passes, an electromagnetic actuator 520 arranged in the guide member 510, and a drive circuit 530 for driving the electromagnetic actuator 520. Electromagnetic actuator 5
20 includes an iron core 521 and an exciting coil 522 that excites the iron core 521. In the guide passage 500, a flexible accommodation space 501 for accumulating the length of the wire A is formed. The bending accommodating space 501 has a substantially isosceles triangular shape and has inclined surfaces 501a and 501b.

Also in this example, the drive circuit 530 is operated by the command signal from the pulsation control unit 31, and the exciting coil 5
When the iron core 521 is excited by 22, magnetic poles are generated,
The wire A is attracted to the iron core 521 side by the magnetic force, which causes the wire A in the guide member 510 to bend as shown in FIG. 7. Further, when the drive circuit 530 is activated by the command signal from the pulsation controller 31 and the exciting coil 522 is demagnetized, the bending of the wire A is released, and the wire A returns to the straight state by its own elastic force. At this time,
Since the wire A is continuously fed by the feed roller 14 at a substantially constant speed (V _W ), the amount of release of the bending is determined by the ejection port 5
Head to 01 side. Therefore, the feeding speed of the wire tip portion A1 sharply increases and is rapidly discharged from the discharge port 501 of the guide member 510 of the pulsating apparatus 50. That is, the wire tip portion A1 is pulsed toward the workpiece 11.

Such excitation and demagnetization requires a pulse current I
_PPulse current I in conjunction with the output of _PFor the output of
Periodically with a constant phase difference, and therefore the wire tip
Portion A1 is periodically pulsed. 8 and 9 show the fifth embodiment. In this example,
As shown, feed roller 14 and feed roller 14 are driven to rotate.
The feeding motor 15 is a robot arm of the robot 80.
It is held at 80n. The pulsation device 60 is the robot 8
It is held by the robot arm 80m of 0.

Also in this example, when the feeding roller 15 is rotationally driven in the direction of arrow P1 by the feeding motor 15, the wire A is guided by the guide 16k and the flexible wire conduit 16 is fed.
Then, it is inserted into the pulsating device 60 through the insertion passage of. The flexible wire conduit 16 has flexibility and is formed of an outer rubber tube 16f and a coil 16h provided inside the outer rubber tube 16f. The wire A is inserted through the coil 16h.

Also in this example, the pulsating device 60 is the torch 1
Equipped with 0. The pulsation device 60 includes a main cylinder 61, a movable cylinder 62 fitted in the main cylinder 61 so as to be movable in the directions of the arrows Y1 and Y2 (= the direction in which the wire A extends), and the movable cylinder 62 in the directions of the arrows Y1 and Y2. And a drive unit 63 for moving the As shown in FIG. 9, the drive unit 63 is provided in the movable cylinder 6
The rotary cam 64 that engages with the rotary cam 64 and the pulsating motor 65 that has a motor shaft 65c that rotationally operates the rotary cam 64 are provided. When the motor shaft 65c of the pulsating motor 65 rotates about the motor shaft center P1, the rotary cam 64 rotates about the motor shaft center P1. As a result, the movable cylinder 62 moves in the arrow Y1 direction with respect to the main cylinder 61. And the arrow Y2 periodically moves alternately.

As can be understood from FIG. 9A, when the rotary cam 64 is rotated by the pulsating motor 65 and the movable barrel 62 is moved in the direction of arrow Y1, the flexible wire conduit is fed from the torch tip portion 10f of the torch 10. 16
Let L1 be the distance to the upper end of the mounting portion 16t. Further, as shown in FIG. 9B, when the movable barrel 62 moves in the direction of the arrow Y2 and the movable barrel 62 floats from the main barrel 61 by ΔLf ′, the mounting portion of the flexible wire conduit 16 from the torch tip portion 10f. The distance to the upper end of 16k increases by ΔLf and becomes L2 (L2> L1).

Here, the flexible wire conduit 16
Although flexible, it does not change the overall length of the flexible wire conduit 16. Therefore, the feeding roller 14
Thus, while continuously feeding the wire A, the entire length of the wire feeding path is momentarily extended by a length corresponding to ΔLf between the feeding roller 14 and the torch tip portion 10f. Therefore, the wire length is accumulated. Note that ΔL
Although f can be appropriately selected, it is generally 0.3 to 1 mm.
The degree can be set to about 0.4 to 0.6 mm.

If the movable barrel 62 moves again in the direction of the arrow Y1 after accumulating the wire length in this way, the accumulated amount corresponding to ΔLf is rapidly eliminated, so that the speed of the wire tip portion A1 is rapidly increased. And thus the wire tip portion A1 is pulsed toward the workpiece 11. Also in this example, pulsation is performed with a predetermined phase difference with respect to the output of the pulse current I _P. ◯ FIG. 10 shows a main part of the sixth embodiment. In this example, the pulsation device 70 displaces the main cylinder 710, the movable cylinder 720 fitted into the main cylinder 710 so as to be displaceable in the directions Y3 and Y4 (= the direction in which the wire A extends), and the movable cylinder 720. An actuator 730 that is a drive source and a drive circuit 740 that drives the actuator 730 are provided. The actuator 730 may be a piezoelectric type formed by a piezoelectric element, or
An electromagnetic system including an iron core and an exciting coil may be used.

In this example as well, if the actuator 730 is driven and the movable barrel 720 is displaced in the direction of the arrow Y4 in the same manner as described above, the wire length is accumulated by ΔLf. Therefore, if the movable cylinder 720 is periodically displaced in the direction of the arrow Y4 and then displaced in the direction of the arrow Y3, the wire length is accumulated and released, and the wire A is pulsed. Also in this example, pulsation is performed with a predetermined phase difference with respect to the output of the pulse current I _P.

(Supplementary Note) The following technical idea can be understood from the above-described embodiments. ○ Wire feeding means for feeding the wire continuously and having a wire tip through the torch toward the work to be welded, and an arc generating current including a pulse current to melt the wire tip. Using a power supply means for generating an arc that is consumed by a wire-consuming pulse arc welding method in which the tip of the wire is pulsed in synchronism with a pulse current or with a predetermined phase difference to approach a workpiece.
While feeding the wire toward the object to be welded at a substantially constant speed by the feeding part of the wire feeding means, the pulsating means causes the wire between the torch tip end facing the object to be welded and the feeding part to be fed. By switching from the first mode in which the wire length is accumulated at least in part to the second mode in which the accumulated amount is released or reduced, the speed of the wire tip portion is temporarily increased and pulsed toward the workpiece. A pulse arc welding method characterized in that the welding is performed.

A pulse arc welding apparatus or method in which the pulsating means is provided with a feeding resistor which is displaceable in a direction intersecting with the wire feeding direction (the wire extending direction). The pulsating means includes a tubular body that can expand and contract in a direction along the wire feeding direction (a wire extending direction), and the length of the wire feeding path is lengthened by ΔLf as the tubular body extends. Pulse arc welding apparatus or pulse arc welding capable of switching between a first mode in which the length is accumulated and a second mode in which the total length of the wire feeding path is returned with the contraction of the tubular body to cancel or reduce the accumulation of the wire length. Method.

As illustrated in FIG. 3, at the time before the rising edge I _Pr of the pulse current I _P , the speed of the tip of the wire is reduced and the wire starts to be accumulated.
A pulse arc welding apparatus and a pulse arc welding method, wherein the feeding speed of the wire tip portion increases after the falling edge _{P Pf} of _P. According to this, it is advantageous to increase the amount of accumulated wire and effectively carry out pulsation.

As illustrated in FIG. 4, at a time point after the rising edge I _Pr of the pulse current I _P , the speed of the tip of the wire is reduced and the accumulation of the wire is started.
A pulse arc welding apparatus and a pulse arc welding method, wherein the feeding speed of the wire tip portion increases after the falling edge _{P Pf} of _P.

According to this, since the wire feeding amount can be secured even when the pulse current I _P is being output, it is advantageous to remove the heat of the contact tip to the wire A. Therefore, it is advantageous for suppressing overheating and thermal damage of the contact tip.

[0065]

According to the wire consumption type pulse arc welding machine of the present invention, there is provided a pulsing means capable of switching between the first mode in which the wire length is accumulated and the second mode in which the accumulated amount is released or reduced. With the switching of the provision and pulsation means from the first form to the second form, the speed of the wire tip is increased and the wire tip is pulsed toward the object to be welded.

Therefore, according to the wire consumption type pulse arc welding machine of the present invention, when the distance between the wire tip and the object to be welded increases with the melting of the wire tip, the interval is promptly increased by pulsing. Can be corrected. Therefore, JP-A-6
Similar to the technique according to Japanese Patent Publication No. 142927, the distance between the tip of the wire and the object to be welded can be maintained, which is advantageous in stabilizing the arc length and can contribute to the improvement of welding quality.

Further, according to the technique disclosed in Japanese Patent Laid-Open No. 6-142927, there is provided a variable controller for varying the feeding speed by the feeding motor for feeding the wire. However, according to the wire consumption type pulse arc welding machine of the present invention, there is a method of utilizing the accumulation of the wire length and the release or reduction of the accumulated amount. Although the two are common in that they are used for pulsation, the pulsation method is different, which is advantageous in avoiding complication of the device and increase in price.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an apparatus according to a first embodiment.

FIG. 2 is a configuration diagram of a pulse delivery device according to the first embodiment.

FIG. 3 is a timing chart showing the relationship between the state of the wire tip and the current and the speed of the wire tip according to the first embodiment.

FIG. 4 is another timing chart showing the relationship between the state of the wire tip and the current and the speed of the wire tip according to the first embodiment.

FIG. 5 is an overall configuration diagram of an apparatus according to a second embodiment.

FIG. 6 is a configuration diagram of a pulse delivery device according to a third embodiment.

FIG. 7 is a configuration diagram of a pulse delivery device according to a fourth embodiment.

FIG. 8 is a configuration diagram showing a state in which a robot arm is equipped with a pulse delivery device according to a fifth embodiment.

FIG. 9 is a configuration diagram showing a main part of a pulse delivery device according to a fifth embodiment.

FIG. 10 is a configuration diagram showing a main part of a pulse delivery device according to a sixth embodiment.

FIG. 11 shows a state of a wire tip portion according to the prior art technique,
7 is a timing chart showing the relationship between the current and the speed of the wire tip.

FIG. 12 shows a state of a wire tip portion according to the prior art,
7 is another timing chart showing the relationship between the current and the speed of the wire tip.

[Explanation of symbols]

In the figure, 1a is a power feeding means, 10 is a torch, 10f is a torch tip, 11 is a workpiece, A is a wire, A1 is a wire tip, A2 is a droplet, 12 is a wire feeding means, and 14 is a feeding means. Rollers (feeding units), 30 is a pulsating device, 31 is a pulsating control unit, 320 and 321 are feeding resistors, and 301 and 302 are bending accommodating spaces.

Claims (1)

[Claims] Claim: What is claimed is: 1. A wire feeding means for feeding a wire, the wire feeding means feeding a wire tip toward a work to be welded, and an arc generating current including a pulse current to melt the wire tip. Feeding means for generating an arc that is consumed by the wire between the tip of the wire and the object to be welded, a first mode for accumulating the wire length in at least a part of the wire, and a method for canceling or reducing the accumulation amount. It is provided so as to be switchable between two modes, and with the switching from the first mode to the second mode, the wire tip portion is attached to the object to be welded in synchronization with the pulse current or with a predetermined phase difference. A wire consumable pulse arc welding machine, comprising: a pulsing means for pulsating.