JPS6344225Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of an arc welding machine that performs welding while feeding a filler wire to a welding part.

In TIG welding machines and plasma welding using non-consumable electrodes, the joints of objects to be welded are heated and melted by an arc, and a filler wire is fed to the welding part to obtain the necessary weld metal. Conventionally, the feed rate of the filler wire has been determined based on the welding current, mainly to control the heat input to the welding part. On the other hand, in order to obtain a high-quality weld, so-called pulse welding is performed by repeatedly changing the welding current high and low. In this case, when feeding the filler wire, controlling the feeding speed in synchronization with the welding current is an important requirement in order to obtain a uniform weld. .

However, in order to perform this kind of pulse welding, it is necessary to prepare a dedicated pulse power source configured so that the output current changes periodically, and such a power source has a lower power consumption than a normal welding power source. It's expensive. Furthermore, there are few devices in which the period, pulse width, pulse peak value, etc. of the pulse current can be arbitrarily adjusted, and even if a dedicated power source is used, the range of application thereof is narrow.

In contrast, the present invention proposes that most commonly used welding power sources are thyristor- or transistor-type power sources that set a reference signal and control the output current to match this signal. To facilitate this, a remote regulator, commonly called a remote control box, is installed at a distance from the main unit of the power supply, and is connected to the main unit by a cable, and the output current receives the signal from this remote regulator. It can be easily adjusted by the signal supplied to the input terminal, and as mentioned above, in welding using pulsed current, changes in filler wire feeding speed and changes in welding current are approximately the same or both. It is an important requirement that the As a result of consideration, by changing the feed speed of the filler wire, detecting the feed speed of the filler wire, and using a signal corresponding to the change in the feed speed as a welding current setting signal, The present invention proposes a pulse arc welding machine in which filler wire feeding speed and changes in welding current always match or have a specific phase relationship without using a dedicated pulse power source.

FIG. 1 shows an embodiment of the present invention. The figure shows an embodiment of the present invention in TIG welding using a tungsten electrode. 1 is a welding torch, 2 is a workpiece, and 3 is a filler wire wound on a reel (not shown) for feeding. It is fed to the welding part through a guide 6 by a feed roll 5 driven by an electric motor 4. 7 is a feeding motor control circuit; 8 is a feeding speed setting circuit; feeding speed setting devices 81, 8;
2. It is composed of a repeatable timer 83 and a power supply 84, each of which can set an ON time and an OFF time. Reference numeral 9 denotes a manual switch that starts a timer 83 to change the filler wire feeding speed, and is attached to the welding torch 1, for example. 10
1 is a welding power source that supplies power between the welding torch 1 and the workpiece 2 from terminals A and B to ignite an arc, and obtains power from a commercial power source (not shown). Reference numeral 11 denotes a detector for detecting the feed speed of the filler wire 3, and in the embodiment shown in the figure, the armature voltage of the feed motor 4, which is proportional to the feed speed, is input and the level is adjusted by a potentiometer. are doing.
Here, the welding power source 10 is a known welding power source with approximately constant current characteristics that outputs a current corresponding to the reference voltage with reference to the voltage input to the terminals C and D, and the motor control circuit 7 is connected to the terminals E and F. This is a known motor control circuit that rotates the motor 4 at a speed corresponding to the reference voltage based on the voltage input to the motor.It is desirable that all of these are of the type that feeds back the output, but if there is sufficient capacity. No particular feedback is required.

In the embodiment shown in FIG. 1, while the manual switch 9 is not closed, no signal is supplied to the motor control circuit 7, so the filler wire feeding motor 4 is stopped. At this time, no signal is supplied to the welding power source 10 like the filler wire feed speed control circuit 7, so the output current is zero. Next, when the manual switch 9 is closed, the timer 83 starts and its normally closed contact 8
3b and the normally open contact 83a are alternately opened and closed at a set period. Here, the first feeding speed setting device 81
If the feed speed of the filler wire determined by The welding current will also change in response to changes in the feed speed. Therefore, even if the welding power source 10 is not a dedicated pulse welding power source, it is possible to perform pulse welding in which the feed speed of the filler wire and the welding current are synchronized.

In the embodiment shown in FIG. 1, the output of the filler wire feed speed detector 11 is directly supplied to the welding power source 10, but when it is desirable that the welding current changes later than the feed speed of the filler wire, A delay circuit may be provided between the feed speed detector 11 and the welding power source 10 to delay changes in the output of the welding power source. Further, the filler wire feeding speed may be set at high speed and low speed, or may be stopped and fed. In this case, the welding power source 10 is the feed speed detector 11.
If the output is zero, a low current is output, and when the output reaches a finite value other than zero, a preset high current is output. Furthermore, the setting circuit for changing the filler wire feed speed is not limited to the combination of the manual switch and timer shown in Fig. 1, but three or more feed speed setting devices are provided and these are set in a specific order. The program may be programmed to sequentially select according to the following. Of course, the present invention can also be applied to a system in which there is only one feed speed setting device and the operator arbitrarily adjusts it to continuously change the filler wire. Further, the setting signal for the motor control circuit 7 may be a voltage signal as shown in the example of FIG. 1, or may be a change in resistance value except for the connection with the power source 84.

FIG. 2 shows another embodiment of the present invention. In this figure, a variable resistor 12 manually operated by an operator is used instead of the feed speed setting circuit 8 of the embodiment shown in FIG.
A speed generator 13 for detecting the rotational speed of the welding power source 10 and a coefficient multiplier 14 for supplying the output of the speed generator as a feedback signal to the motor control circuit and as an output current setting signal for the welding power source 10 are used. be.

In the embodiment shown in FIG. 2, during welding, when the operator operates the variable resistor 12 to feed the filler wire 3 at a speed that provides a predetermined amount of welding, the speed generator 13 is proportional to the rotational speed of the electric motor 4. generates a voltage.
This output voltage undergoes necessary waveform shaping and level adjustment by the coefficient unit 14, is fed back to the motor control circuit 7, and is also supplied to the welding power source 10. As a result, the welding power source 10 outputs a current commensurate with the feeding speed of the filler wire 3. Therefore, even if the condition of the welded object changes, the operator only has to adjust the variable resistor 12 so that the amount of filler wire fed is commensurate with the change while visually checking the welding area, which eliminates complicated work. It is possible to easily perform good welding even on objects to be welded that have an uneven shape, a welding groove shape, or a gap.

As described above, in this invention, the output of the welding power source changes according to the change in feed speed of the filler wire, so the output current can be controlled remotely without the need for a dedicated pulse welding power source. Pulse welding using a filler wire can be performed by a general-purpose welding power source that can be controlled. Of course, the period, peak value, and pulse width of the pulse current at this time can be controlled arbitrarily. In addition, since the feed speed of the filler wire is used as a reference and a commensurate welding current is supplied, the feed rate of the filler wire is determined based on the change in the conventional welding current. Unlike this method, welding can be performed by adjusting the feed rate of filler wire, which directly affects the amount of welding, according to changes in the groove shape of the welding part or changes in the required amount of extra metal, making the work extremely easy. It has many effects, such as:

[Brief explanation of the drawing]

1 and 2 are connection diagrams showing an embodiment of the present invention. 1... Welding torch, 2... Work to be welded, 3... Filler wire, 4... Filler wire feeding motor, 7...
Motor control circuit, 8... Feeding speed setting circuit, 9...
...Manual switch, 10... Welding power source, 11... Feed speed detector, 12, 81, 82... Feed speed setting device.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. In an arc welding machine that performs welding by lighting an arc between a non-consumable electrode and a workpiece and feeding filler wire to the welding area, the filler wire feeding speed a setting circuit, a filler wire feeding device that receives the output of the filler wire feeding speed setting circuit and feeds the filler wire at a speed according to an input signal, and detects the feeding speed of the filler wire. An arc welding machine comprising: a feed speed detector; and a welding power source that outputs a current according to an output signal of the feed speed detector. 2 The feeding speed setting circuit is a setting device that outputs two signals for feeding and stopping the filler wire at a predetermined speed, and the welding power source applies a high current when feeding the filler wire and when stopping the filler wire. The arc welding machine according to claim 1, which is a power source that sometimes outputs a low current. 3. The feed speed setting circuit is a setting device that outputs two high and low signals for feeding the filler wire at a high speed and a low speed, and the welding power source controls the feed speed of the filler wire. The arc welding machine according to claim 1, which is a power source that outputs a high current and a low current according to the height of the current. 4. The feed speed setting circuit is a circuit that repeatedly selects the plurality of feed speed setters in a predetermined order by a plurality of setters and a presettable timer. The arc welding machine according to any one of items 1 to 3. 5. The arc welding machine according to any one of claims 1 to 3, wherein the feed speed setting circuit is manually operated by an operator. 6. The welding power source is a power source whose output current is remotely adjustable and has a remote adjustment signal input terminal, and the output signal of the feed speed detector is supplied to the remote adjustment signal input terminal. The arc welding machine according to any one of items 1 to 5.