JPH11767A - Welding equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding equipment capable of flowing the preset welding current and capable of reducing the variance of the welding. SOLUTION: A welding equipment 10 includes AC power sources 14a, 14b, phase regulation circuits 16a, 16b, transformers 18a, 18b, and switching elements 20a, 20b. The secondary winding of the transformer 18a is connected to a welding electrode 22a and a grounding electrode 24. The secondary winding of the transformer 18b is connected to a welding electrode 22b and the grounding electrode 24. The welding electrodes 22a, 22b and the grounding electrode 24 are brought into contact with a work 30 to be welded. The phase regulation devices 16a, 16b and the switching elements 20a, 20b regulate the welding current so that the starting polarity of the welding currents i1 , i2 is as preset.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a welding device,
In particular, for example, the present invention relates to a welding device for simultaneously welding a plurality of portions of a workpiece.

[0002]

2. Description of the Related Art FIG. 7 is an illustrative view showing one example of a conventional welding device, and FIG. 8 is an equivalent circuit diagram thereof. Welding equipment 1
Include welding power sources 2a and 2b. Welding power supply 2a, 2b
Are a plurality of AC power supplies 3a, 3b, a switching element 4
a, 4b and transformers 5a, 5b. AC power supply 3a is connected to the primary winding of transformer 5a via switching element 4a. The AC power supply 3b is
Connected to the primary winding of transformer 5b via switching element 4b. The secondary winding of transformer 5a is connected to one welding electrode 6a and ground electrode 7. The secondary winding of the transformer 5b is connected to the other welding electrode 6b and the ground electrode 7.

[0003] The two welding electrodes 6 a and 6 b and the ground electrode 7 are brought into contact with a workpiece 9 placed on a welding stage 8. The workpiece 9 is placed on the welding stage 8 via, for example, an insulator. Then, a welding current flows from the welding electrodes 6a and 6b to the workpiece 9 by the switching elements 4a and 4b. At this time, from the welding electrodes 6a and 6b, for example, as shown by a solid line in FIG.
The welding currents i ₁ and i ₂ having phases opposite to each other are set to flow. Thereby, at the portion where the two welding electrodes 6a and 6b are in contact with each other, the workpiece 9 is welded,
The welding current is offset in the ground electrode 7 portion. Therefore, almost no current flows through the ground electrode 7, and the workpiece 9 is not welded at a portion where the ground electrode 7 is in contact. In this way, a plurality of portions of the workpiece 9 are simultaneously welded.

In some cases, as shown in FIG. 10, a time difference is provided so that welding currents i ₁ and i ₂ of positive rise from the welding electrodes 6a and 6b flow to the work 9 to be welded. In this case, a current also flows through the ground electrode 7,
By increasing the contact area between the ground electrode 7 and the workpiece 9, the contact resistance between them can be reduced and the generated Joule heat can be reduced. Therefore, the workpiece 9 is not welded to the ground electrode 7.

[0005]

However, even if the phases of a plurality of welding currents are adjusted, a welding current having an out-of-set phase may flow at a rate of about once every tens of times. For example, if one welding current and the other welding current are set to rise to a positive polarity with a time lag, and if welding currents of opposite phases flow at the same time, a large current will flow in the welded part and There is a problem that the welded portion of the welded material is too molten.

[0006] When one welding current and the other welding current are set so as to simultaneously rise in opposite polarities, if a positive rising welding current flows with a time lag, the current flowing in the welding portion is increased. Becomes smaller than the set value, and the welding strength is weakened. As described above, there is a problem in that the variation in the rising polarity of the set welding current causes variation in the welding state of the workpiece.

[0007] Therefore, a main object of the present invention is to provide a welding apparatus which can flow a welding current as set, thereby reducing welding variations.

[0008]

SUMMARY OF THE INVENTION The present invention provides a plurality of welding power sources, the same number of welding power sources as the number of welding power sources formed for supplying a welding current from the welding power source to a workpiece, a welding power source, a welding electrode, and A ground electrode for forming a welding circuit in cooperation with the workpiece; and a control unit for controlling a rising polarity of a welding current flowing from the welding electrode to the workpiece. . In this welding device, the control means can be constituted by switching means for interrupting the welding current flowing through the welding electrode, and a phase adjusting circuit for controlling the phase of the welding current.

By providing the control means, the rising polarity of the welding current flowing from the plurality of welding electrodes to the workpiece is controlled. Therefore, the rising polarity as set can always be obtained. For example, when the welding current is controlled by the switching means and the phase adjusting circuit, after the switching means closes the circuit, the welding current is passed by the phase adjusting circuit at a portion having a predetermined rising polarity.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0011]

FIG. 1 is an illustrative view showing one embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram thereof. The welding device 10 includes welding power supplies 12a and 12b. Welding power source 12
a and 12b include AC power supplies 14a and 14b, respectively. The AC power supply 14a is connected via a phase adjustment circuit 16a to
It is connected to one end of the primary winding of the transformer 18a. The AC power supply 14a is connected to the other end of the primary winding of the transformer 18a via a switching element 20a as switching means. Similarly, the AC power supply 14b
It is connected to one end of the primary winding of the transformer 18b via the phase adjustment circuit 16b. Further, the AC power supply 14b
It is connected to the other end of the primary winding of the transformer 18b via a switching element 20b as switching means. Semiconductor switching elements such as thyristors are used as these switching elements 20a and 20b. These switching elements 20a, 20
b and the phase adjusting circuits 16a and 16b form a control circuit for controlling the rising polarity of the welding current.

At one end of the secondary winding of the transformer 18a,
The welding electrode 22a is connected. Further, an earth electrode 24 is connected to the other end of the secondary winding of the transformer 18a.
Similarly, another welding electrode 22b is connected to one end of the secondary winding of the transformer 18b. Further, the transformer 18b
The above-mentioned earth electrode 24 is connected to the other end of the secondary winding.

The workpiece 30 is mounted on a welding stage 32. At this time, an insulator 34, for example, is placed on the welding stage 32, and the workpiece 30 is placed thereon. Then, the welding electrodes 22a and 22b are brought into contact with the welding portion of the workpiece 30. Also, the workpiece 3
The ground electrode 24 is brought into contact with a portion other than the 0 welded portion. These welding power sources 12a, 12b, phase adjustment circuits 16a, 16b, earth electrode 24 and workpiece 30
Thus, a welding circuit is formed. At this time, FIG.
As shown in (1), the area of the contact portion between the ground electrode 24 and the workpiece 30 is set to be larger than the contact area between the welding electrodes 22a and 22b and the workpiece 30. With this setting, the contact resistance between the ground electrode 24 and the workpiece 30 can be made smaller than the contact resistance between the welding electrodes 22a and 22b and the workpiece 30.

As shown in FIG. 4, the welding apparatus 10 uses, for example, a commercial frequency current. In this embodiment, as shown by a dotted line in FIG. 4, currents having phases opposite to each other are output from the AC power supply 14a and the AC power supply 14b. When the workpiece 30 is welded using the welding device 10, the switching elements 20a and 20b are operated by, for example, a welding signal, and the circuit is closed.
However, due to the presence of the phase adjustment circuits 16a and 16b, the transformer
No current flows through a and 18b. That is, the welding electrode 22
a, i, the welding currents i ₁ , i
_{When 2} is set to have the reverse polarity rising, current is not supplied to the primary windings of the transformers 18a and 18b by the phase adjusting circuits 16a and 16b until the reverse polarity rising occurs.

Then, as shown by the solid line in FIG. 4, at the portion where the reverse polarity rises, one of the transformers 18a and 18b
When a current is supplied to the next winding and a current for one wavelength flows, the switching elements 20a and 20b operate to open the circuit. Therefore, the welding currents i ₁ , i ₂ having the opposite polarities are supplied from the welding electrodes 22a, 22b to the workpiece 30 by one wavelength.

That is, one of the welding currents i ₁ has a negative polarity rise by the phase adjustment circuits 16 a and 16 b,
And the other of the welding current i ₂ as a positive rise, current is supplied to the transformer 18a, 18b of the primary winding. Therefore, a welding current is simultaneously supplied to the workpiece 30 from the welding electrodes 22a and 22b. Since these welding currents are in opposite phases to each other, they are canceled at the ground electrode 24 and almost no current flows through the ground electrode 24. Therefore, the workpiece 30 is not welded at a portion where the ground electrode 24 contacts.

As shown in FIG. 5, when the two welding currents i ₁ and i ₂ are set so as to have a positive rise, the switching element 20 is switched by a welding signal or the like.
After the operation of the welding currents i ₁ , i ₂
Until the positive polarity rises, the transformers 18a, 18
No current is supplied to the primary winding b. Then, as shown by the solid line in FIG. 5, when both welding currents i ₁ and i ₂ have a positive polarity rise, current is supplied to the primary windings of the transformers 18a and 18b. The AC power supplies 14a, 14
Since the current output from b is out of phase, the welding current i
_{When 1} and i ₂ are controlled so as to have a positive polarity, the welding currents i ₁ and i ₂ have a time shift of １ ／ wavelength. Such welding currents i ₁ , i ₂
Thereby, the workpiece 30 is welded at a portion where the welding electrodes 22a and 22b are in contact. In the ground electrode 24, the portions where the two welding currents i ₁ and i ₂ are in opposite phases are canceled. Therefore, half the wavelength of each of the welding currents i ₁ and i ₂ flows through the ground electrode 24. However, since the contact resistance between the ground electrode 24 and the workpiece 30 is small, Joule heat is generated. Less occurrence. Therefore, the workpiece 30 is not welded at a portion where the ground electrode 24 contacts.

As described above, in the welding apparatus 10, since the rising polarity of the welding current can be accurately controlled, welding can be performed as set. Therefore, welding at a plurality of locations can be performed at the same time, and there is little variation in the welding state, and occurrence of poor welding can be prevented.

As shown in FIG. 6, by bringing the welding electrodes 22a to 22n into contact with three or more portions of the work 30 to be welded, welding can be performed simultaneously on a large number of portions. In this case, for example, every other one of the welding electrodes 22a to 22n is set to have the same rising state. As described above, even when a large number of portions of the workpiece 30 are welded at the same time, by applying the present invention,
The effects described above can be obtained. That is, by controlling the rising state of the welding current flowing through each of the welding electrodes 22a to 22n by the phase adjusting circuits 16a to 16n, it is possible to reduce variations in the welding state.

[0020]

According to the present invention, it is possible to simultaneously weld a large number of portions of a workpiece. Moreover, since the rising polarity of the welding current can be controlled as set, variations in the welding state such as excessive melting of the welded portion and poor welding strength can be reduced.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing one embodiment of the present invention;

FIG. 2 is an equivalent circuit diagram of the welding device shown in FIG.

3 is an illustrative view showing a contact area between a welding electrode and a work to be welded and a contact area between a ground electrode and a work to be welded in the welding apparatus shown in FIG. 1;

FIG. 4 is a waveform diagram showing an example of a welding current when two welding locations are welded using the welding device shown in FIG.

FIG. 5 is a waveform diagram showing another example of a welding current when two welding locations are welded using the welding device shown in FIG.

FIG. 6 is a conceptual diagram showing an example of a welding apparatus for performing welding at a number of locations on a workpiece.

FIG. 7 is an illustrative view showing one example of a conventional welding device;

8 is an equivalent circuit diagram of the conventional welding device shown in FIG.

FIG. 9 is a waveform diagram showing an example of a welding current when two welding locations are welded using a conventional welding device.

FIG. 10 is a waveform diagram showing another example of a welding current when two welding locations are welded using a conventional welding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Welding apparatus 12a, 12b Welding power supply 14a, 14b AC power supply 16a, 16b Phase adjustment circuit 18a, 18b Transformer 20a, 20b Switching element 22a, 22b Welding electrode 24 Earth electrode 30 Workpiece 32 Welding stage 34 Insulator

Claims (2)

[Claims] 1. A plurality of welding power sources, the same number of welding electrodes as the welding power sources formed to flow a welding current from the welding power source to the workpiece, and the welding power source, the welding electrodes and the workpiece. A welding apparatus, comprising: a ground electrode for forming a welding circuit in cooperation with each other; and control means for controlling a rising polarity of a welding current flowing from the welding electrode to the workpiece. 2. The switching unit according to claim 2, wherein the control unit switches the welding current flowing through the welding electrode.
The welding apparatus according to claim 1, further comprising a phase adjustment circuit for controlling a phase of the welding current.