JPS6350076Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an automatic lowering device for welding current.

Conventionally, automatic lowering of the welding current was carried out at the end of welding accompanied by crater treatment, as shown in the current distribution diagram in Figure 1, and the lowering of the welding current during welding was done exclusively by manually moving the welding current volume. I relied on means.

However, as shown in Fig. 2, when welding the boss 01 to the large-diameter pipe 02 made of Al material, when welding with a constant welding current, welding heat accumulates.
Development of a device that automatically reduces the welding current in accordance with the distance traveled by the torch in order to avoid the accumulation of welding heat, since the beads and back waves become gradually larger and irregular, impairing the quality and appearance of the weld. has become necessary.

The present invention was proposed in view of the above circumstances, and is used in welding equipment for welding objects that need to be welded without accumulating welding heat on the objects. a pulse generator that generates a pulse for each movement amount; a digital counter that detects the output pulses of the pulse generator every fixed number; and a stepping relay that sequentially switches stepping contacts by inputting the output of the digital counter. The present invention is characterized by comprising a resistor that increases sequentially by switching the stepping relay contacts.

An embodiment in which the present invention is applied to welding a boss to a large diameter aluminum pipe as shown in Fig. 2 will be explained with reference to the drawings. Fig. 3 is a side view thereof, and Fig. 4 is a - 5 is a block diagram showing the circuit configuration of the present invention, and FIG.
FIG. 7 is a circuit diagram showing the resistance switched by the stepping relay shown in FIG.

In the above figure, 1 is an aluminum boss to be welded to a large-diameter aluminum pipe 2, and 3 is an aluminum boss that rotates around the axis Z-Z of the boss 1, and welds the large-diameter aluminum pipe 2 and the boss 1 along a circular welding line. 4 is a welding wire that is fed to the welding part; 5 is a welding torch that rotates in conjunction with the rotation axis of the welding torch 3; A pulse generator such as a transducer that outputs pulses; 6 a digital counter that counts the pulses output from the pulse generator 5 and outputs a count-up signal every fixed number; 7 a digital counter that outputs a count-up signal output from the digital counter 6; Conversion output and terminal A stepping contacts a, b,
A stepping relay switches the connection in the order of c'...,l, and 9 is a resistor that increases the resistance between terminals A and B in a stepwise manner by switching the stepping contacts a, b, c'...l in a stepwise manner. A and B are respectively inserted into the output current circuit of the welding machine.

In such a device, when welding is performed, the pulse generator 5 outputs one pulse for every 1 degree rotation of the rotation axis of the welding torch 3, corresponding to the distance the welding torch 3 moves. , the digital counter 6 detects pulses at regular intervals and operates the stepping relay 7 to switch the contacts a, b, c...l.
Switch in this order. In this way, while the welding torch 3 rotates once, the stepping relay 7 a,
The stepping contacts are switched 12 times in the order of b, c...l, and each time the stepping contacts are switched, the resistance 9 between AB increases stepwise, and the welding current changes stepwise as shown in Figure 7. decreases by 5A.

Therefore, the digital counter 6 can be set to 10, for example.
When set to , the welding current decreases by 5A each time the welding torch rotates 10 degrees, and the welding current decreases by 180A in total after one rotation. Also, a digital counter
If set to 20, the welding current will decrease by 5A for every 20° rotation of the welding torch, and the welding torch will
The reduction in current when rotating 360° is 5A x 18 = 90A.

According to such a device, the welding current automatically decreases in accordance with the distance the torch moves.
The phenomenon of welding heat accumulating in the welding object does not occur, and aluminum materials, etc., can be welded with excellent quality in both beads and back waves.

In short, according to the present invention, in a welding device for a workpiece that needs to be welded while preventing welding heat from accumulating on the workpiece, a pulse is generated every time the welding torch moves a certain distance corresponding to the distance traveled by the welding torch. A pulse generator, a digital counter that detects the output pulses of the pulse generator at regular intervals, a stepping relay that sequentially switches stepping contacts by inputting the output of the digital counter, and switching of the stepping relay contacts. The present invention is extremely useful industrially because it provides a welding current drop device that performs high quality welding of materials such as aluminum where the accumulation of welding heat has an adverse effect on quality by providing a resistor that gradually increases. It is.

[Brief explanation of the drawing]

Fig. 1 is a current distribution diagram showing automatic welding current drop for known crater treatment, Fig. 2 is a perspective view showing a large diameter aluminum pipe with a boss welded on, and Fig. 3 is a current distribution diagram showing the automatic welding current drop for conventional crater treatment. A side view showing an embodiment applied to welding a boss, FIG.
Fig. 5 is a block diagram showing the circuit configuration of the present invention, Fig. 6 is a circuit diagram showing the resistance switched by the stepping relay of Fig. 5, and Fig. 7 shows the welding current by this device. FIG. 1... Boss, 2... Large diameter aluminum tube, 3... Welding torch, 4... Welding wire, 5... Pulse generator, 6... Digital counter, 7... Stepping relay, 9... Resistance circuit , a, b, c…l…
Stepping contact.

Claims (1)

[Scope of utility model registration request] In a welding device for a workpiece that needs to be welded while preventing welding heat from accumulating on the workpiece, there is provided a pulse generator that generates a pulse for each fixed distance of movement of a welding torch, and a pulse generator that generates a pulse for each fixed distance of movement of a welding torch. a digital counter that detects output pulses of the device every fixed number; a stepping relay that sequentially switches stepping contacts by inputting the output of the digital counter; and a resistor that increases sequentially by switching the stepping relay contacts. An automatic welding current lowering device characterized by: