JP2009248085A - Ac welding apparatus and ac welding equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem in which AC welding equipment needs to be purchased when AC welding is performed, that is, even if DC welding equipment is owned, purchase of AC welding equipment is separately required when AC welding is desired. <P>SOLUTION: The DC welding equipment is connected to an AC welding apparatus which includes: a first input part for inputting a DC output that is output by the DC welding equipment; a switching circuit for switching the DC output from the DC welding equipment input in the first input part into positive and negative and performing AC output; a second input part for inputting a signal output by the DC welding equipment so as to control the switching circuit; and an output part for supplying to a welding load AC output that is output by the switching circuit, the AC welding apparatus being provided separately from the DC welding equipment, and the DC output of the DC welding equipment is input in the AC welding apparatus, with AC outputting performed from the AC welding apparatus to the welding load. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a welding apparatus that performs arc welding by generating an arc between an electrode and an object to be welded. More specifically, the present invention relates to welding with an electrode by inputting the DC output of a DC welding apparatus that performs DC output. The present invention relates to an AC welding apparatus and an AC welding apparatus for performing AC output with an object.

  As welding apparatuses that perform welding, there are a DC welding apparatus that performs DC output between an electrode and a welding object, and an AC welding apparatus that performs AC output between an electrode and a welding object.

  The main component of the DC welding equipment is that it has a transformer, a rectifier, and a smoother. The input voltage supplied from the primary side is stepped down by the transformer, converted to direct current by the rectifier, and smoothed by the smoother. And what supplies a direct-current output between an electrode and a welding target object is known (for example, refer patent document 1).

Moreover, as an AC welding apparatus, as a main configuration, a bridge diode, a primary inverter circuit, a transformer, a rectifier diode, and a secondary inverter circuit are provided, and an AC input is rectified to DC with a bridge diode, and a primary inverter circuit is used. It is known to convert to high frequency alternating current, step down with a transformer, rectify to direct current with a rectifier diode, convert to alternating current with a secondary inverter circuit, and supply alternating current output between the electrode and the welding object (For example, refer to Patent Document 2).
JP 58-009770 A JP-A-3-124374

  In the conventional welding apparatus, when performing AC welding, it was necessary to purchase an AC welding apparatus. That is, even if the DC welding apparatus is owned, there is a problem that if the AC welding is desired, the AC welding apparatus must be purchased separately from the DC welding apparatus. In recent years, a control device in which a robot control device and a welding power source device are integrated is known as a welding machine built-in robot, and such a control device is more expensive than a welding device. And when the welding output of this control apparatus is a direct current output, when performing an alternating current output, it is necessary to purchase the control apparatus which performs an alternating current output separately, and there exists a subject that cost burden becomes large.

  An object of the present invention is to make it possible to perform AC welding using a DC welding apparatus even when the existing welding apparatus is a DC welding apparatus.

  In order to solve the above problems, an AC welding apparatus of the present invention includes a first input unit that inputs a DC output output from a DC welding device, and a DC current from the DC welding device that is input at the first input unit. A switching circuit that switches the output between positive and negative to make an AC output, a second input unit that inputs a signal output from the DC welding device to control the switching circuit, and an AC output that the switching circuit outputs And an output unit for supplying the welding load to the welding load. The output unit is provided separately from the direct current welding apparatus, and the direct current output of the direct current welding apparatus is input to perform the alternating current output to the welding load.

  In the AC welding apparatus of the present invention, in addition to the above, the first input unit includes a first input terminal and a second input terminal, and the switching is performed between at least one input terminal and a switching circuit. A current backflow prevention element for preventing a current from flowing backward from the circuit toward the first input portion is provided.

  Moreover, in addition to the above, in the AC welding apparatus of the present invention, the first input unit includes a first input terminal and a second input terminal, and the first input terminal and the terminal of the second input terminal. A voltage absorbing element is provided between them.

  In addition to the above, in the AC welding apparatus of the present invention, the first input unit includes a first input terminal and a second input terminal, and the output unit includes the first output terminal and the second output terminal. And when the electrode has a positive polarity and the work piece has a negative polarity, and when the electrode has a negative polarity and the work piece has a positive polarity, the input terminal of the first input unit has a positive polarity. The combined impedance obtained by synthesizing the impedance of the path to the output terminal and the impedance of the path from the other output terminal of the output unit to the other input terminal of the first input unit is substantially the same.

  In addition to the above, in the AC welding apparatus of the present invention, the switching circuit is configured by bridge-connecting a plurality of switching units, and each switching unit is configured by connecting a plurality of switching elements in parallel.

  In addition to the above, in the AC welding apparatus of the present invention, the DC welding device is built in a control device that controls the welding robot.

  Moreover, the AC welding apparatus of the present invention includes a DC welding apparatus that outputs a DC output, a first input unit that inputs a DC output that is output from the DC welding apparatus, and the DC that is input through the first input unit. A switching circuit for switching a DC output from a welding apparatus to an AC output by switching between positive and negative, a second input unit for inputting a signal output from the DC welding apparatus to control the switching circuit, and the switching circuit And an AC welding device provided separately from the DC welding device, and electrically connecting the DC welding device and the AC welding device to each other. , The DC output of the DC welding device is input to the AC welding equipment, and AC output is performed from the AC welding equipment to the welding load.

  As described above, according to the present invention, by connecting an AC welding apparatus to a DC welding apparatus, welding can be performed by changing the DC output of the DC welding apparatus from the AC welding apparatus to an AC output. AC welding can be realized by utilizing it.

(Embodiment 1)
An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a schematic configuration of an AC welding apparatus including a DC welding apparatus 2 and an AC welding apparatus 1 provided separately from the DC welding apparatus 2 and connected to the DC welding apparatus 2.

  In FIG. 1, an AC welding apparatus 1 has a first input unit 3 for inputting a DC output output by the DC welding device 2 and a positive DC output from the DC welding device 2 input by the first input unit 3. Switching circuit unit 5 that switches to negative to make AC output, second input unit 4 that inputs a control signal output from DC welding device 2 to control switching circuit unit 5, and switching circuit unit 5 outputs An output unit 6 for supplying an AC output to the welding load is provided. The first input unit 3 includes a first input terminal 15 and a second input terminal 16. The output unit 6 includes a first output terminal 17 and a second output terminal 18.

  In addition, although not shown in figure, the direct current welding apparatus 2 is equipped with the structure similar to the known general direct current welding apparatus which was shown in background arts, such as a transformer, a rectification | straightening part, and a smooth part, as main structures. The input voltage supplied from the primary side is stepped down by a transformer, converted into direct current by a rectifier, and smoothed by a smoothing unit to supply a direct current output between the electrode and the welding object. . The main difference from the known general DC welding apparatus is that it has a function of sending a control signal for controlling the switching circuit portion 5 of the AC welding equipment 1 to the AC welding equipment 1. Specifically, the DC welding apparatus 2 includes a storage unit 23 that stores AC waveform output information, a control unit 24 that generates a control signal based on information stored in the storage unit, and an AC welding device that transmits the control signal. The output part 25 which outputs to 1 is provided, The function which sends a control signal to the alternating current welding apparatus 1 by these is implement | achieved. When used as a welding device that performs normal DC output, the DC welding device 2 stores waveform information of the DC welding output and performs welding output based on the waveform information, but operates as a part of the AC welding device. In this case, the welding output is performed based on the waveform information of the AC welding output stored in the storage unit 23.

  In addition, the AC welding equipment 1 does not include a primary inverter circuit, a transformer, or the like that is included in a known general AC welding apparatus as shown in the background art. Compared to a small, simple and inexpensive configuration, it is an additional unit for AC for realizing AC welding.

  The AC welding device 1 inputs the DC output output from the DC welding device 2 to the first input unit 3 of the AC welding device 1. The DC input input from the first input unit 3 is a case where the switching circuit unit 5 outputs a welding current in a positive direction from the welding torch 7 to the welding base material 8 as a welding object (hereinafter referred to as EP output). ) And when the welding current is output from the welding base material 8 to the welding torch 7 in the positive direction, that is, when the welding current is output from the welding torch 7 to the welding base material 8 in the negative direction (hereinafter referred to as EN output). .

  The switching circuit unit 5 of the AC welding equipment 1 includes four switching elements 9, 10, 11, and 12 and four switching element protection parts (not shown) that are attached to each of the four switching elements. At the time of EP output, the switching element 9 and the switching element 12 are closed, and the switching element 10 and the switching element 11 are opened. On the other hand, at the time of EN output, the switching element 10 and the switching element 11 are closed, and the switching element 9 and the switching element 12 are opened. A control signal output from the DC welding apparatus 2 is input to the second input unit 4 of the AC welding apparatus 1, and the operation timing of each switching element of the switching circuit unit 5 is controlled by the control signal input from the second input unit 4. Is done.

  And the alternating current output which the switching circuit part 5 outputs is supplied between the welding torch 7 which is a welding load, and the welding preform | base_material 8 from the output part 6 of the alternating current welding apparatus 1, and can thereby perform alternating current welding.

  Further, the switching circuit unit 5 can control the AC output frequency, the ratio of the EP output and the EN output, and the like according to the control signal output from the DC welding device 2, and the welding torch 7 which is a welding load and the welding base material. 8 can be supplied.

  As described above, according to the present embodiment, the direct current output of the direct current welding apparatus 2 can be obtained by connecting the alternating current welding apparatus 1 that is smaller, simpler and less expensive than the general alternating current welding apparatus to the direct current welding apparatus 2. AC welding can be performed with AC output from the AC welding equipment 1, and AC welding can be realized using the DC welding device 2. That is, it is possible to perform AC welding in addition to DC welding by additionally connecting the AC welding equipment 1 to the DC welding device 2.

  Then, AC welding can be realized using the AC welding apparatus 1 and the DC welding apparatus 2 by purchasing the AC welding apparatus 1 which is smaller, simpler and cheaper than the AC welding apparatus without purchasing an AC welding apparatus separately. It is possible to expand welding variations at low cost.

  In addition, as a producer of welding equipment, without producing two types of welding equipment, DC welding equipment and AC welding equipment, only DC welding equipment 2 and AC welding equipment 1 can be used for direct current welding and alternating current welding. This can improve the productivity of the welding equipment and strengthen the cost power, and can provide the welding equipment at a lower cost.

  In addition, the DC welding apparatus 2 of this Embodiment can be used as a welding apparatus which performs DC output by using it alone. Moreover, it can use also as an AC welding apparatus which performs AC output by connecting and using AC welding equipment 1.

  Then, when it is desired to use an expensive robot control device incorporating the DC welding device 2 as a welding device that performs AC output, the AC welding device 1 of the present embodiment is connected to the DC welding device 2 in the robot control device. By adopting a configuration, AC welding is possible. Therefore, by constructing an AC welding apparatus using the AC welding equipment 1 of the present embodiment, AC welding can be performed without purchasing an expensive robot control apparatus incorporating a welding apparatus for AC welding. It is very effective in terms of aspect.

  Moreover, in the AC welding equipment 1 of the present embodiment, the output of the output unit 6 from the first input terminal 15 of the first input unit 3 in the case of the EP output by the operation of the switching circuit 5 and the case of the EN output. The wiring is made to have substantially the same circuit impedance to the second input terminal 16 of the first input unit 3 through the terminals (17, 18).

  Specifically, the circuit impedance from the first input terminal 15 to the first output terminal 15 via the switching element 9 and the second input from the second output terminal 18 via the switching element 12 at the time of EP output. From the EP output circuit impedance obtained by synthesizing the circuit impedance up to the terminal 16, the circuit impedance from the first input terminal 15 to the second output terminal 18 through the switching element 10 and the first output terminal 17 at the time of EN output. The wiring distance and the wiring cross-sectional area are determined and the wiring is routed so that the EN output circuit impedance obtained by synthesizing the circuit impedance up to the second input terminal 16 via the switching element 11 is substantially the same. .

  Thereby, the voltage drop of wiring can be made substantially the same at the time of EP output and EN output, and the stable welding voltage can be supplied between the welding torch 7 which is a welding load, and the welding base material 8. And stable welding is possible.

(Embodiment 2)
In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 2 is a diagram showing a schematic configuration of the DC welding apparatus 2 and the AC welding apparatus 1 connectable to the DC welding apparatus 2 in the present embodiment.

  The main difference from the first embodiment is that the current backflow prevents current from flowing backward from the switching circuit 5 to the input terminal 15 between the input terminal 15 of the first input unit 3 and the switching circuit 5. The point provided with the prevention element 13 and the point provided with the voltage absorption element 14 between the terminals of the first input terminal 15 and the second input terminal 16. Examples of the current backflow prevention element 13 include a block diode and the like, and examples of the voltage absorption element 14 include an RCD snubber and a ZNR (varistor).

  By disposing the current backflow prevention element 13, when AC output is stopped, the DC welding device 2, the AC welding equipment 1, the welding torch 7, which is a welding load, and the welding base material 8, and the connection between each are configured. A counter electromotive voltage corresponding to the circuit impedance is generated, and the current generated by the counter electromotive voltage flows backward from the switching circuit unit 5 toward the input terminal 3 to switch the switching elements 9, 10, 11, 12 or a switching element (not shown) in the DC welding apparatus 2 can be prevented from being damaged.

  Further, when AC output is stopped, a counter electromotive voltage is generated according to the circuit impedance constituted by the DC welding device 2, the AC welding equipment 1, the welding torch 7 which is a welding load, and the welding base material 8 and the connection between each. However, this back electromotive force is applied to the switching elements 9, 10, 11, 12 in the AC welding equipment 1, the switching elements (not shown) in the DC welding apparatus 2, etc. 1 and the DC welding apparatus 2 can be prevented from being damaged by providing the voltage absorbing element 14.

  In the present embodiment, an example in which both the current backflow prevention element 13 and the voltage absorption element 14 are provided in the AC welding apparatus 1 has been described, but only one of them may be provided.

  Moreover, since the AC welding apparatus 1 and the DC welding apparatus 2 are provided separately and are configured to be electrically connected by a cable or the like, the DC welding apparatus 2, the AC welding apparatus 1, and the welding torch 7 that is a welding load. In such a case, the current backflow prevention element 13 and the voltage absorption element 14 are provided, because the circuit impedance formed by the connection between the welding base material 8 and between each of the welding base material 8 is likely to be high, and the back electromotive voltage is likely to be high. Is very effective.

(Embodiment 3)
In the present embodiment, the same parts as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 3 is a diagram illustrating a schematic configuration of the DC welding apparatus 2 according to the present embodiment and the AC welding equipment 1 that can be connected to the DC welding apparatus 2.

  The main difference from the first and second embodiments is that the switching circuit unit 5 is provided with switching units 19, 20, 21, and 22 configured by connecting two switching elements 9, 10, 11, and 12 in parallel. This is the point. In addition, by connecting switching elements in parallel, there is an advantage that heat resistance and current resistance are improved, cooling efficiency is also improved, and a cooling device provided in the AC welding equipment 1 can be simplified.

  As in the case of the circuit operation and effect of the first embodiment, the output unit from the input terminal (15 · 16) of the first input unit 3 in the case of the EP output by the operation of the switching circuit 5 and the case of the EN output. The wirings are such that the circuit impedances up to 6 output terminals (17, 18) are substantially the same.

  Specifically, the circuit impedance from the first input terminal 15 to the first output terminal 15 through the switching unit 19 and the second input from the second output terminal 18 through the switching unit 12 at the time of EP output. From the EP output circuit impedance obtained by synthesizing the circuit impedance up to the terminal 16, the circuit impedance from the first input terminal 15 to the second output terminal 18 through the switching unit 10 at the time of EN output, and the first output terminal 17 The wiring distance and the wiring cross-sectional area are determined and the wiring is routed so that the EN output circuit impedance obtained by synthesizing the circuit impedance up to the second input terminal 16 via the switching unit 11 is substantially the same. .

  As a result, the voltage drop at the wiring portion can be made substantially the same, and a stable welding voltage can be supplied between the welding torch 7 and the welding base material 8 as a welding load, enabling stable welding. It becomes.

  Note that if the switching elements are connected in parallel, the difference in circuit impedance is likely to be larger than in the case where the switching elements of the first embodiment are not connected in parallel as compared to the case of one, so that the case of EP output and the case of EN output Thus, it is very effective to make the wiring so that the circuit impedances are substantially the same.

  In this embodiment, an example in which two switching elements are connected in parallel to form a switching unit has been described. However, the present invention is not limited to this, and three or more switching elements may be connected in parallel as necessary.

  According to the present invention, the DC welding device and the AC welding device are electrically connected, the DC output of the DC welding device is input to the AC welding device, and the AC output is performed from the AC welding device to the welding load. This is industrially useful because AC welding can be realized using a DC welding apparatus.

The figure which shows schematic structure of the AC welding apparatus and DC welding apparatus in Embodiment 1 of this invention The figure which shows schematic structure of the AC welding apparatus and DC welding apparatus in Embodiment 2 of this invention. The figure which shows schematic structure of the AC welding apparatus and DC welding apparatus in Embodiment 3 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 AC welding apparatus 2 DC welding apparatus 3 1st input part 4 2nd input part 5 Switching circuit part 6 Output part 7 Welding torch 8 Welding base material 9 Switching element (EP output side)
10 Switching element (EN output side)
11 Switching element (EN output side)
12 Switching element (EP output side)
DESCRIPTION OF SYMBOLS 13 Current backflow prevention element 14 Voltage absorption element 15 1st input terminal 16 2nd input terminal 17 1st output terminal 18 2nd output terminal 19 Switching part (EP output side)
20 Switching section (EN output side)
21 Switching section (EN output side)
22 Switching section (EP output side)
23 Storage Unit 24 Control Unit 25 Output Unit

Claims (7)

A first input unit for inputting a DC output output by the DC welding apparatus;
A switching circuit that switches the direct current output from the direct current welding apparatus input at the first input unit to positive and negative to make an alternating current output;
A second input unit for inputting a signal output from the DC welding apparatus to control the switching circuit;
An output unit for supplying an AC output output by the switching circuit to a welding load;
An AC welding apparatus that is provided separately from the DC welding apparatus and that inputs a DC output of the DC welding apparatus and outputs an AC output to the welding load. The first input unit includes a first input terminal and a second input terminal, and current flows backward from the switching circuit toward the first input unit between at least one input terminal and the switching circuit. The AC welding apparatus according to claim 1, further comprising a current backflow prevention element for preventing this. The first input unit includes a first input terminal and a second input terminal,
The AC welding apparatus according to claim 1 or 2, wherein a voltage absorption element is provided between the first input terminal and the second input terminal. The first input unit includes a first input terminal and a second input terminal,
The output unit includes a first output terminal and a second output terminal,
When the electrode has a positive polarity and the workpiece has a negative polarity, and when the electrode has a negative polarity and the workpiece has a positive polarity, the input terminal of the first input section to the output terminal of the output section The combined impedance obtained by synthesizing the impedance of the path up to and the impedance of the path from the other output terminal of the output unit to the other input terminal of the first input unit is substantially the same. The AC welding apparatus according to item 1. The switching circuit is configured by bridge-connecting multiple switching units,
5. The AC welding apparatus according to claim 1, wherein each switching unit includes a plurality of switching elements connected in parallel. The DC welding apparatus according to any one of claims 1 to 5, wherein the DC welding apparatus is built in a control device that controls the welding robot. A DC welding device that outputs a DC output;
A first input unit that inputs a DC output output from the DC welding device; and a switching circuit that switches the DC output from the DC welding device input at the first input unit between positive and negative to make an AC output. A second input unit for inputting a signal output from the DC welding device to control the switching circuit; and an output unit for supplying an AC output output from the switching circuit to a welding load. AC welding equipment provided separately from the DC welding device,
AC welding that electrically connects the DC welding apparatus and the AC welding equipment, inputs a DC output of the DC welding equipment to the AC welding equipment, and performs AC output from the AC welding equipment to the welding load. apparatus.

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