JPH11197828A - Device for detecting arc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely detect the development of arc at the time of starting an automatic welding so as to transmit a starting command signal to a driving system in each device. SOLUTION: It is judged whether the arc develops or not by comparing a welding voltage signal Varc from a welding voltage detector 8 with a reference arc voltage signal Vref from a reference arc voltage setter 9. Then, a primary arc decision device 10 for outputting a signal Vc indicating that the arc develops, in the case of judging that the arc develops, and a secondary arc decision device 11 for finally judging that the arc develops, in the case of being given the signal Vc from the primary arc decision 10 and a current detecting signal IC from a current detecting relay signal relay detector 7 are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an arc detecting apparatus which can reliably detect whether or not an arc has been generated during automatic welding, thereby improving the reliability of the apparatus.

[0002]

2. Description of the Related Art Conventionally, in performing automatic welding, if a welding current flows from a welding power source at the start of welding, a welding current source provided in the welding power source is provided.
lay), the welding current is detected as a current detection relay signal, and when the current detection relay signal is detected, it is determined that an arc has occurred in the electrode. Then, this current detection relay signal is given as a start command signal accompanying the arc generation to devices such as a welding torch moving device, a wire feeding device, and a work rotating device, and by activating the starting system of each device, the movement of the torch and the wire Feeding, rotating workpieces, etc.

[0003]

However, in the above-mentioned conventional means, particularly in the case of TIG welding, the current detection relay signal is detected even if the electrode and the work are welded for some reason at the start of welding. It is determined that an arc has occurred despite the fact that an arc has not actually occurred, and the drive system of each device is activated.

Accordingly, in such a case, not only normal welding cannot be performed, but also the welding torch welded to the work tends to move, and as a result, troubles such as breakage of the torch may occur.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has as its object to improve the reliability of an apparatus by reliably detecting whether an arc has occurred at the start of automatic welding.

[0006]

According to the present invention, there is provided a current detection relay signal generator for processing a current detection relay signal provided when a welding current is generated in a welding power supply at the start of automatic welding and outputting the current detection relay signal as a current detection signal. A welding voltage detector that processes a welding voltage acting on a welding torch and a work and outputs the same as a welding voltage signal, and compares a welding voltage signal from the welding voltage detector with a reference arc voltage signal from a reference arc voltage setting device. A primary arc determiner that outputs a signal indicating that an arc is present when it is determined that an arc is occurring, and if it is determined that an arc is present, an arc presence signal from the primary arc determiner and the current detection. When a current detection signal is given from a relay signal generator, a secondary arc determination device that finally determines that an arc is present is provided.

[0007] In the present invention, the primary arc judging device compares the welding voltage signal from the welding voltage detector with the reference arc voltage signal from the reference arc voltage setting device to judge whether or not an arc is generated, and determines whether the arc is generated. When it is determined that there is an arc, an arc present signal is output, and the secondary arc determiner receives both the arc present signal from the primary arc determiner and the current detection signal from the current detection relay signal generator. In the case where an arc is present, it is finally determined that there is an arc.

Therefore, according to the present invention, the presence or absence of an arc is determined by 2
Since it can be determined at the stage, it is not determined that an arc has occurred even though no arc has occurred, and as a result, it is possible to accurately determine whether or not an arc is occurring Thus, the reliability of the device is improved.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of an embodiment of the present invention showing an example of a TIG welding apparatus. In the figure, reference numeral 1 denotes a welding power source equipped with a WCR, and 2 denotes a power supply from a welding power source 1 via a cable 3. A welding torch 5 for welding the work 4 by an electric current, 5 is an electrode to be fed through the welding torch 2, and 6 is a cable connecting the work 4 and the welding power source 1.

Reference numeral 7 denotes a current detection relay signal detector for confirming that the current detection relay signal Ir has flown into the WCR provided in the welding power source 1, and reference numeral 8 acts between the welding torch 2 and the work 4. The welding voltage detector 8 detects a voltage. The welding voltage detector 8 includes a signal amplification circuit and a waveform shaping circuit (not shown), and shapes a no-load voltage and an arc voltage to a predetermined voltage. It is possible to do.

Reference numeral 9 denotes a reference arc voltage setter, 10 denotes a welding voltage signal Varc detected by the welding voltage detector 8 and a reference arc voltage signal V set by the reference arc voltage setter 9.
ref (usually about 9 to 20 V) to determine whether or not an arc is generated from the electrode 5;
Reference numeral 11 denotes a current detection signal Ic from the current detection relay signal detector 7 and an arc presence signal Vc from the primary arc determiner 10.
Is given, an AND circuit type that outputs a start command signal X for starting a drive system of each device such as a welding torch moving device, a wire feeding device, a work rotating device, etc. Of the secondary arc.

Next, the operation of the embodiment of the present invention will be described with reference to FIG.

When automatic welding is normally performed, when the torch switch is turned on, the welding voltage rises instantaneously as a no-load voltage, and immediately falls to the arc voltage.
Also, after turning on the torch switch, a slight time delay t
And a welding current flows, and power is supplied to the welding torch 2 (see FIGS. 1 and 2).

At this time, the WCR of the welding power source 1 detects that the welding current has flowed, is given to the current detection relay signal detector 7 as a current detection relay signal Ir, is processed, and is processed as a secondary current detection signal Ic. It is given to the arc judging device 11.

On the other hand, the welding voltage V acting between the welding torch 2 and the work 4 is detected by the welding voltage detector 8, shaped and amplified to a predetermined level, and the welding voltage signal Varc
Is given to the primary arc determiner 10.

The reference arc voltage signal Vref set in the reference arc voltage setting device 9 is supplied to a primary arc determination device 10 in which the welding voltage signal Varc and the reference arc voltage signal Vref are converted. Be compared.

If Varc> Vref, it is determined that an arc is occurring, and the primary arc determiner 10 supplies an arc presence signal Vc to the secondary arc determiner 11.

Therefore, since both the current detection signal Ic and the arc presence signal Vc are supplied to the secondary arc decision unit 11, the secondary arc decision unit 11 finally determines that there is an arc. As a result, a start command signal X is output from the secondary arc determiner 11 and given to a drive system of equipment such as a welding torch moving device, a wire feeding device, and a work rotating device.
Each device is activated and welding is started.

As a result of the comparison between the welding voltage signal Varc and the reference arc voltage signal Vref in the primary arc determination unit 10,
If Varc <Vref, the electrode 5 is in contact with the work 4 and the primary arc determination unit 10 outputs an arc presence signal Vc.
Is not output. Therefore, only the current detection signal Ic from the current detection relay signal detector 7 is input to the secondary arc determiner 11 and the secondary arc determiner 11 does not determine that there is an arc. Does not output the start command signal X.

Accordingly, the driving systems such as the welding torch moving device, the wire feeding device, and the work rotating device are not activated, and each device remains stopped. Therefore, the welding torch 2 is not damaged by the movement of the welding torch 2.

In the embodiment of the present invention, the presence / absence of an arc is determined in two stages. Therefore, it is determined that an arc is generated although an arc is not actually generated. As a result, it is possible to accurately determine whether or not an arc is generated, and the reliability of the device is improved.

It should be noted that the present invention is not limited only to the above-described embodiment, and it is needless to say that various changes can be made without departing from the spirit of the present invention.

[0024]

According to the arc detecting device of the present invention, it is possible to reliably detect an arc at the start of automatic welding, and therefore an excellent effect that the reliability of the device is improved can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of an embodiment of an arc detection device according to the present invention.

FIG. 2 is a graph showing a relationship between welding current, welding voltage and time when a torch switch is turned on in a TIG welding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Welding power supply 2 Welding torch 4 Work 7 Current detection relay signal detector 8 Welding voltage detector 9 Reference arc voltage setting device 10 Primary arc determining device 11 Secondary arc determining device V Welding voltage Varc Welding voltage signal Vref Reference arc voltage signal Ir Current detection relay signal Ic Current detection signal Vc Signal with arc

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masashi Okamoto 5292 Aioi, Aioi-shi, Hyogo Ishikawajima-Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] 1. A current detection relay signal generator for processing a current detection relay signal given when a welding current is generated in a welding power source at the start of automatic welding and outputting the signal as a current detection signal, and a welding voltage acting on a welding torch and a workpiece. And outputs a welding voltage signal as a welding voltage signal, and compares the welding voltage signal from the welding voltage detector with the reference arc voltage signal from the reference arc voltage setting device to determine whether or not an arc is emitted. When it is determined that an arc is generated, a primary arc determiner that outputs a signal indicating that an arc is present, an arc presence signal from the primary arc determiner and a current detection signal from the current detection relay signal generator are output. An arc detection device, comprising: a secondary arc determiner that, when given, finally determines that an arc is present.