JPH07251266A - Controller for tungusten inert gas welding machine - Google Patents

Abstract

PURPOSE:To provide a controller for a tungsten inert gas(TIG) welding machine which can reduce and simplify an operational panel surface of the TIG welding machine. CONSTITUTION:This device is provided with a mode selecting signal C which instructs either welding state of an usual welding or an arc spot welding, an ON.OFF signal A of a torch switch, and a former part circuit 2 which outputs a time controlling signal D, E based on a current detecting signal B to detect a current in an arc load. Further, it is provided with a time controlling circuit 4 which outputs a slope controlling signal based on the time controlling signal D, E impressed from the former part circuit 2, and a post part circuit 5a which impresses a controlling signal onto a welding power source 6 making the slope controlling signal as the current controlling signal of the arc load in the usual welding case, and making a slope finishing point of the slope controlling signal as a breaking point or the current against the arc load 7 in the arc spot welding case, based on the slope controlling signal impressed from the time controlling circuit 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a TIG welding machine, and more particularly to reducing the operation panel surface of the TIG welding machine.
The present invention relates to a control device for a TIG welding machine that enables simplification.

[0002]

2. Description of the Related Art A general operation sequence of a TIG welding machine will be described with reference to FIGS. FIG. 3 is an operation sequence diagram at the time of normal welding. When the torch switch is turned on, an arc is generated and an initial current I ₁ flows, and when the torch switch is turned off thereafter, the welding current is regulated after the up-slope time t _1. Increase to current value I ₂ , then
When the torch switch is turned on again, the crater filler current I ₃ is passed after the down slope time t ₂ and the welding is completed when the torch switch is turned off.

FIG. 4 is an operation sequence diagram at the time of arc spot welding. When the torch switch is turned on, an arc is generated, a prescribed welding current flows, and when the set time t ₃ elapses, the current is cut off and the welding is finished.

FIG. 5 is a block diagram showing a conventional controller for a TIG welding machine that executes such a sequence. In the figure, the control device 1 is the O of the torch switch.
The N / OFF signal A, the current detection signal B, and the mode selection signal C are applied, and at the time of arc spot welding, the time control signal D consisting of the logical product of the ON / OFF signal A of the torch switch and the current detection signal B is output. However, at the time of normal welding, from the start circuit 2 that outputs the slope control signal E based on the ON / OFF signal A of the torch switch and the time control signal D, from the start of the current supply to the arc load to the interruption. And a time control circuit for outputting a slope waveform for changing the current applied to the arc load at a set time to a required current value based on the slope control signal E. 4, the ON / OFF signal A of the torch switch, the current detection signal B, and the mode selection signal C are applied, and based on the outputs of the time control circuits 3 and 4, It is constituted by a rear stage circuit 5 that outputs a control signal that matches the record mode. A welding power source 6 is controlled by the controller 1. An arc load 7 is connected to the welding power source 2.

As shown in FIG. 6, the time control circuit 3 is composed of a clamp diode D ₁ , a variable resistor VR ₁ , a capacitor C ₁ , resistors R _{1 to} R ₄ , and an operational amplifier A ₁ . Then, when the torch switch is turned on and the current starts to flow in the arc load, the logical product is applied from the preceding circuit 2 to the time control circuit as the time control signal D, which is the "H" level input 8. Then, the capacitor C ₁ starts to be charged by the power source voltage Vcc through the variable resistors VR ₁ and R ₂ , and when the voltage of the capacitor C ₁ exceeds the reference voltage obtained by dividing the power source voltage Vcc by the resistors R ₃ R ₄ , calculation is performed. The output 9 of the amplifier A ₁ changes from "L" level to "H" level. This level change of the output 9 is applied to the rear circuit 5 as a current cutoff signal for the arc load 7. The length of welding time is adjusted by the variable resistance VR ₁ .

As shown in FIG. 7, the time control circuit 4 includes a charging diode D ₂ , a discharging diode D ₃ , a variable resistor VR ₂ , resistors R _{5 to} R ₁₀ , a capacitor C ₂ and an operational amplifier A _2. It is composed of an integrating circuit.

When controlling the downslope in normal welding, the "H" level input 10 is applied as the downslope control signal E from the preceding circuit 2 to the time control circuit 4 by the rise of the ON signal A of the torch switch. To be done. Then, the capacitor C ₂ is charged in the direction shown by the path of the resistor R ₅ , the diode D ₂ , the variable resistor VR ₂ , the resistor R ₈ , and the capacitor C ₂ . At this time, the output 11 is
The waveform has a slope-like change from Vcc to 0V.
The waveform of the output 11 is applied to the post-stage circuit 5 as a downslope signal of the welding current applied to the arc load 7. In addition, adjustment of the length of the slope time is performed by the variable resistor V
Perform at R ₂ .

The post-stage circuit 5 sends a control signal to the welding power source 6 based on the signals applied from the time control circuits 3 and 4 to control the current of the arc load 7.

[0009]

As described above, when the normal welding and the arc spot welding are switched by the TIG welding machine, since the control signals required for the respective welding modes are different, the welding modes are different. Each of them has a separate time control circuit. Therefore, a knob for adjusting the time for operating each of the variable resistors VR ₁ and VR ₂ is required, and even if the TIG welding machine itself is downsized due to the adoption of an inverter control welding power source, the operation panel surface is downsized. It was a constraint on the conversion.

In view of the above-mentioned problems, an object of the present invention is to use a time control circuit and a time adjusting knob which are necessary for slope control during normal welding and time control during arc spot welding as a common operation knob. An object of the present invention is to provide a control device for a TIG welding machine, which can reduce the number of devices, and can reduce the size and simplification of the operation panel surface.

[0011]

In order to achieve the above object, in the present invention, a mode selection signal for instructing a welding mode of either normal welding or arc spot welding, and a torch switch ON / OFF signal. Based on the current detection signal that detects the current flowing in the arc load, the slope control signal is output based on the time control signal applied from the front stage circuit and the integrating circuit that outputs the time control signal. Based on the time control circuit to output, the ON / OFF signal of the torch switch applied via the preceding circuit, the current detection signal detecting the current flowing in the arc load, and the slope control signal applied from the time control circuit, In the case of normal welding, the slope control signal is used as the current control signal of the arc load, and in the case of arc spot welding, the slope control signal is slowed down. Provided and the rear stage circuit for applying a control signal to the welding power source end point as a blocking point of current to the arc load.

[0012]

In normal welding, the post-stage circuit to which the slope control signal output from the time control circuit is applied, applies the slope control signal to the welding power source as a current control signal of the arc load to perform arc spot welding. In this case, the post-stage circuit to which the slope control signal output from the time control circuit is applied is applied to the welding power source by applying the slope end point of the slope control signal to the welding power source as the interruption point of the current to the arc load. It became possible to share.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. This embodiment is an example in which the time control circuit for down slope control is shared with the time control circuit for arc spot welding. In FIG. 1, the control device 1a is
A torch switch ON / OFF signal A, a current detection signal B, and a mode selection signal C are applied, and at the time of arc spot welding, a time control signal composed of the logical product of the torch switch ON / OFF signal A and the current detection signal B. Output D,
Torch switch ON / OFF signal A during normal welding
Based on the pre-stage circuit 2 that outputs the slope control signal E and the time control signal D or the slope control signal E, the current applied to the arc load at the set time is set to the required current value. Time control circuit 4 that outputs a slope waveform to change to, and torch switch ON / O
The FF signal A, the current detection signal B, and the mode selection signal C are applied, and based on the output of the time control circuit 4, the post-stage circuit 5a is configured to output a control signal suitable for each mode. A welding power source 6 is controlled by the controller 1. An arc load 7 is connected to the welding power source 2.

As shown in FIG. 7, the time control circuit 4 includes a charging diode D ₂ , a discharging diode D ₃ , a variable resistor VR ₂ , resistors R _{5 to} R ₁₀ , a capacitor C ₂ and an operational amplifier A _2. It is composed of an integrating circuit. Then, the time is controlled by changing the resistance value of the variable resistor VR ₂ and changing the charging time of the capacitor C ₂ .

With this configuration, in the arc spot welding, the torch switch is turned on in the pre-stage circuit 2 for which the arc spot welding is instructed by the mode selection signal C, and when the welding current starts to flow in the arc load 7, the torch switch is turned on. O
A time control signal D consisting of a logical product of the N signal and the current detection signal is applied to the time control circuit 4. In the time control circuit 4 to which the time control signal D is applied, when the input 10 becomes the “H” level, the capacitor C ₂ is charged to the polarity shown and the output 1
1 changes in a slope form from the power supply voltage Vcc to 0V.
This output 11 is applied to the subsequent circuit 5a.

Arc spot welding is instructed by the mode selection signal C, and the torch switch ON / OFF signal A
The current detection signal B and the output 11 of the time control circuit 4 are applied to the latter-stage circuit 5a to control the welding power source 6 according to the operation sequence shown in FIG. That is, the time control circuit 4
It is detected by a comparator (not shown) that the output 11 of the output changes in a slope shape as shown in FIG. 2 (a) to reach a predetermined level (0 V in this example), and as shown in FIG. 2 (b). And a signal that changes from "H" level to "L" level is generated. Then, as shown in FIG. 2D, after the time control signal D shown in FIG.
The time t ₃ until the signal shown in (b) changes to the "L" level is controlled to be the time for energizing the arc load 7.

In the case of normal welding, the mode selection signal C
In the pre-stage circuit 2 for which normal welding was instructed, the torch switch is turned on again while the welding current is flowing in the arc load 7.
The ON signal at this time is applied to the time control circuit 4 as the down slope control signal E. In the time control circuit 4 to which the time control signal D is applied, when the input 10 becomes the “H” level, the capacitor C ₂ is charged to the polarity shown and the output 11
Changes in a slope form from the power supply voltage Vcc to 0V. This output 11 is applied to the subsequent circuit 5a.

The latter stage circuit 5a instructed by the mode selection signal C for normal welding controls the welding power source 6 in accordance with the waveform of the output 11 applied from the time control circuit 4.
At this time, the time required for the output to change from the power supply voltage Vcc to 0 V is the down slope time t ₂ in FIG.

In the above embodiment, the case where the time control circuit for arc spot welding and the time control circuit for downslope are shared is described. However, the time control circuit for arc spot welding and the upslope are used. The time control circuit may be shared.

[0020]

As described above, according to the present invention, a mode selection signal for instructing a welding mode of either normal welding or arc spot welding and ON / OF of a torch switch are provided.
A pre-stage circuit that outputs a time control signal based on the F signal and the current detection signal obtained by detecting the current flowing through the arc load;
A time control circuit that is composed of an integrator circuit and that outputs a slope control signal based on the time control signal that is applied from the preceding circuit, a torch switch ON / OFF signal that is applied through the preceding circuit, and an arc load. Based on the current detection signal that detected the flowing current and the slope control signal applied from the time control circuit, the slope control signal is used as the current control signal of the arc load in the case of normal welding, and the slope control signal in the case of arc spot welding. Since the latter stage circuit that applies a control signal to the welding power source with the slope end point of the above as the current interruption point for the arc load is provided, the time control circuit for arc spot welding and the time control for down slope or up slope are provided. Since the circuit can be shared, the configuration of the control circuit of the TIG welding machine can be simplified. Further, the time adjustment knob can be reduced, and the operation panel surface of the TIG welding machine, which tends to be downsized, can be reduced and simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit of a control device according to the present invention.

2 is an operation sequence diagram of the latter-stage circuit in FIG. 1 during arc spot welding.

FIG. 3 is an operation sequence diagram of the TIG welding machine during normal welding.

FIG. 4 is an operation sequence diagram of the TIG welding machine during arc spot welding.

FIG. 5 is a block diagram showing a circuit of a conventional control device.

6 is a detailed diagram of the time control circuit 3 in FIG.

7 is a detailed view of the time control circuit 4 in FIG.

[Explanation of symbols]

 1a Control device 2 Pre-stage circuit 4 Time control circuit 5a Post-stage circuit 6 Welding power source 7 Arc load

Claims (1)

[Claims] 1. A mode selection signal indicating a welding form of either normal welding or arc spot welding, an ON / OFF signal of a torch switch, and a current detection signal detecting a current flowing through an arc load, A pre-stage circuit that outputs a time control signal and an integrating circuit. A time control circuit that outputs a slope control signal based on the time control signal applied from the pre-stage circuit, and a torch switch that is applied via the pre-stage circuit. In the case of normal welding, the slope control signal is used as the current control signal of the arc load based on the ON / OFF signal of, the current detection signal detecting the current flowing in the arc load, and the slope control signal applied from the time control circuit. In the case of arc spot welding, the slope power control signal is controlled by the welding power source as the current cutoff point for the arc load. TIG welding machine control apparatus characterized by comprising a subsequent circuit for applying a degree.