JPS5970476A - Automatic welding device - Google Patents

Abstract

PURPOSE:To regulate a torch automatically to equalize weak current at the ends and form a recessed penetration bead free from defect by moving a torch repeatedly to left and right in the direction of width in a groove, and applying welding current at the center of movement and applying weak current outside of the center. CONSTITUTION:A torch 12 is moved to left and right repeatedly by a servo motor 22 of a slide unit 20 within a specified width in the groove of an object 10 to be welded. Welding current is let flow to the torch at the center of movement by a current controlling mechanism of the body 30 of a welding device and weak arc current that does not melt the base metal is let flow outside of the center of movement. At this time, arc voltages Va, Vb of left and right ends 12a, 12b of movement of the torch 12 are detected by a detector 24. The voltage difference Va-Vb is calculated by a comparator circuit 26, and amplified by an amplifier 28, and a servo motor 22 is operated to bring the center of movement of the torch 12 always to the center of groove 10a of the object 10 to be welded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic welding device, and more particularly to an automatic welding device that detects the center of a groove of a workpiece and performs welding while aligning a welding torch with the center of the groove.

Conventionally, the welding/welding device shown in Fig. 1 is a welding device that performs welding following the center of a groove cut into a workpiece. The base material is 12
is a welding torch, and the welding torch 12 has a knob screw 1 for manually adjusting the welding torch 12 by moving it left and right within the groove.
A slide mechanism 16 marked with 4 is attached.

Figures 2 and 3 show welding conditions when the first layer is welded using the above-mentioned welding device, and generally speaking, the first layer welds have a busy welding speed 18 as shown in Figure 2. It is necessary to weld so that a convex bead 18a is formed on the back side of the workpiece 10, but as shown in FIG. If so, the weld bead 18 on the back side of the object to be welded 10 becomes a concave bead ISB, resulting in insufficient welding strength and welding defects. Further, even if the weld bead 18 becomes wider than necessary, a concave bead 18b will be formed on the back side of the workpiece 10, similar to when the welding torch 12 is deviated from the groove center 10a.

Therefore, in conventional welding equipment, during welding, the knob screw 14 is appropriately moved by hand so that the welding torch 12 and the groove center 10a do not deviate, and the slide mechanism 16 is used to align the welding torch 12 with the groove center 10a. Had to adjust the move.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to repeatedly move a welding torch left and right in the groove width direction of a workpiece, and to A main welding current is passed through the welding electrode at the center, and a weak arc current that does not melt the base metal to be welded is passed through the welding torch outside the center of movement, and the arc voltage at each of the left and right moving ends of the welding torch is detected. To provide an automatic welding device capable of always performing welding without welding defects by detecting the position of the center of a groove and automatically aligning the center of movement of a welding torch with the position of the center of the groove. There is a particular thing.

In order to achieve the above object, the present invention provides a welding apparatus in which a moving mechanism is attached to the welding torch to repeatedly move the welding torch from side to side in the groove width direction within the groove of the base material to be welded. A current control mechanism is installed to apply the main welding current to the welding torch at the center of movement, and to send a weak arc current that does not melt the base metal to be welded outside the center of movement, and furthermore, to prevent arcing at the moving ends of the left and right tables of the welding torch inside the groove. The present invention is characterized by the provision of a control mechanism that detects the voltage and automatically adjusts the center of movement of the welding torch within the groove so that the arc voltages at each moving end become equal.

Further, in the present invention, the control mechanism for automatically adjusting the center of movement of the welding torch includes a detection device that detects the arc voltage at each left and right moving end of the welding torch, and a detected difference between the arc voltages at each left and right moving end. A comparator circuit that calculates the arc voltage, an amplifier that amplifies the difference between the compared arc voltages, and a slide unit that receives the output signal from the amplifier and appropriately moves the center of movement of the welding torch is preferable.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings. Note that in FIGS. 4 and 5, the same members as those in the conventional device shown in FIG.

In FIG. 4, reference numeral 2o designates a moving mechanism that uses a driving servo motor 22 to repeatedly move the welding torch 12 from side to side within a predetermined movement width, and a control mechanism that moves and adjusts the center of movement of the welding torch 12 as appropriate. With a slide unit that has both
A rear end portion of a welding torch 12 is fixed to the output end of the slide unit 2°. 24 is a detector that detects the arc voltage at each of the left and right moving ends of the welding torch 12, 26 is a comparison circuit that calculates the difference in arc voltage between the left and right moving ends of the welding torch 12, and 28 is the compared arc voltage. 9.30 indicates the welding machine main body that controls the welding current.

Further, FIG. 5 shows the relationship between each position of the welding torch 12 moving within the groove and the arc voltage, and vl is when the welding torch 12 is located at the left moving end 12a within the groove. The arc voltage [, Vb is when the welding torch 12 is at the left moving end 1
2bK is the arc voltage when the welding torch 12 is positioned, and 32 indicates the movement width of the welding torch 12.

To perform welding using the welding apparatus configured as described above, the drive servo motor 22 of the slide unit 20 is used to drive the moving mechanism to move the welding torch 12 left and right within the groove of the workpiece 10 by a predetermined movement width. The main welding current is applied to the welding torch 12 at the center of movement using the current control mechanism provided in the welding machine main body 30, and the base material to be welded is melted outside the center of movement. Supervision - 'Current flow 17
6.1. ,.

At that time, the left and right moving ends 12 of the welding torch 12
．． Detector 2 detects arc voltages Va and vb at a and 12b.
4 to detect the difference in arc voltage (Va-Vb).
.

The comparator circuit calculates the voltage difference, and the amplifier 28 amplifies this voltage difference to a voltage that can drive the drive servo motor 22 of the slide unit.The voltage is applied to the drive servo motor 22 to operate it, using the control mechanism of the slide unit 20. The center of movement of the welding torch 12 is adjusted so that the center of movement of the welding torch 12 is always on the groove center 10a of the workpiece 10 to be welded.

As described above, when welding is performed using the automatic welding device of the present invention, the center of movement of the welding torch is always on the groove center of the workpiece, and when the welding torch is on the groove center of the workpiece, It becomes possible to perform welding by only supplying the main welding current to the welding torch, and it is possible to always form a convex bead without welding defects on the back side of the workpiece.

In addition, since a weak arc current that does not melt the workpiece is applied to the welding torch outside the center of movement of the welding torch, the weld bead is wide and a concave bead is formed on the back side of the workpiece. ．． There are effects such as no welding defects occurring.

[Brief explanation of the drawing]

FIG. 1 is a partial schematic diagram of a conventional welding device, FIGS. 2 and 3 are comparison diagrams of weld bead shapes of workpieces, and FIG. 4 is a schematic diagram of a welding device of the present invention. ) FIG. 5 is an explanatory diagram showing the relationship between the position of the welding torch and the arc voltage. In each figure, the same members are given the same reference numerals, and 10 is a workpiece, 10a is a groove center, 12 is a welding torch, 20 is a slide unit, and 30 is a welding machine main body. Agent Patent attorney Shin Kuzuno - (11 or 1 person) (8) Figure 2 Figure 1 6 00 Sun Figure 4 Figure 5

Claims (2)

[Claims] (1) In the welding equipment □, a moving mechanism is attached to the welding torch that repeatedly moves the welding torch left and right in the groove width direction within the groove of the base material to be welded, and the welding torch A current control mechanism is installed to flow the main welding current and a weak arc current that does not melt the base material to be welded outside the center of movement.
, and a control mechanism that detects the arc voltage at the left and right moving ends of the welding torch within the groove and automatically adjusts the center of movement of the welding torch within the groove so that the arc voltages at each moving end are equal. An automatic welding device characterized by being provided with. (2) In the device according to claim (1), the control mechanism that automatically adjusts the center of movement of the welding torch includes a detection device that detects arc voltage at each left and right moving end of the welding torch; A comparison circuit that calculates the difference in arc voltage between the left and right moving ends, an amplifier that amplifies the difference between the compared arc voltages, and an output signal from the amplifier that moves the center of movement of the welding torch as appropriate. An automatic welding device characterized in that it consists of a slide unit that allows