JPS6239895Y2 - - Google Patents

Description

[Detailed description of the invention] This invention bends the welding wire in MIG or MAG welding for narrow grooves, and
The present invention relates to a welding wire feeding device that feeds a welding wire to a welding groove.

In recent years, with dramatic advances in welding technology, narrow gap welding methods have been developed to reduce the width of the groove when welding large, thick plate structures, etc., in order to shorten the work time. It came to this. This narrow gap welding method is
It is used exclusively for MIG welding and MAG welding, and as shown in Figure 1, which shows the principle, a pair of thick plate-shaped members 1 to be welded are butted against each other to form a narrow groove 2.
A continuously bent welding wire 4 is fed through the guide nozzle 3, and an arc 5 is formed between the tip of the welding wire 4 and the workpiece 1.
The pair of members 1 to be welded are welded together through the welded portion 6 formed by the generation of . According to this narrow gap welding method, there is no need to form a special groove part by cutting on the workpiece 1, and since the narrow groove part 2 is used, the welded part 6
Because the amount of formation is small, it is possible to perform welding work with high efficiency.

The present invention provides a welding wire feeding device that feeds the welding wire into such a narrow gap while bending the welding wire. A pair of gears are arranged so that their tips and roots coincide with each other and rotate synchronously, and the welding wire is fed out with a bend. Flat parts are provided at the tips and roots of the triangular tooth profile of the pair of gears. It is characterized by

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a welding wire feeding device according to the present invention will be described in detail based on an embodiment shown in the drawings.

The device according to the present invention bends the welding wire into a shape in which the movement of the welding arc substantially stops at both ends of the oscillation, and feeds the welding wire to the welding groove. An embodiment of an apparatus for forming such a bent state is shown in FIG. The gear 7 and the gear 8 are meshed with a gap large enough to engage the welding wire 9. The gears 7 and 8 rotate synchronously so that the tips and roots of the teeth are always aligned with each other. In this embodiment, the tooth profile is a complex single-edged sawtooth shape, so to speak, the gear has a triangular tooth profile, with flat portions formed at the tip and root of the tooth. In this embodiment, the same gears are arranged in opposite directions so that the gears 7 and 8 face each other so that the tips and roots of the pair of gears mesh with each other without any gaps. The gears 7 and 8 are divided into four equal parts from the tooth root a to the next tooth root a, and the quarter points are indicated by b, c, and d in order. Therefore, the flat portion is . If the distances from the center of the gear to a, b, c, and d are Da, Db, Dc, and Dd, then Da+Dc=Db
+Dd=constant. This is to ensure that when the same gears are oriented in opposite directions and meshed together as gear 7 and gear 8, they mesh without any gaps. Gears 7 and 8 having such shapes are installed with a distance between the shafts L≒Da+Dc+d ₁ (d ₁ is the diameter of the welding wire 9), and the mechanism rotates with the tips and roots of each tooth always matching. It's summery.

When the welding wire 9 is supplied between the rotating gears 7 and 8, the welding wire 9 is forced to be plastically deformed into a shape substantially the same as the tooth profile of the gears. That is, in this embodiment, the welding wire 9 has a bending width W
(corresponding to Dc-Da), welding wire 10 bent in two stages (small bending angle α, large bending angle β) at bending pitch P (corresponding to the distance from a to the next a) is obtained and welded. It is fed to the groove.

Using the welding wire 10 bent and fed by the welding wire feeding device configured as above,
When performing MIG or TIG welding, while an arc is generated in the part m with an angle α, the arc oscillation is slightly stopped near the side wall of the weld groove, and the arc oscillation is slightly stopped near the side wall of the weld groove While the arc is occurring in the area, the arc reciprocates along both side walls. In this way, the oscillation of the arc almost stops near the side wall, so the weld bead penetration width is the fourth.
Wide as shown. Therefore, it is much better than the conventional welding using a straight welding wire (see FIG. 3). Furthermore, in terms of welding speed, the bending pitch P is 10 to 20 mm, and the welding wire diameter d ₁
When the welding current is 1.2mm and the welding current is 300Amp, the oscillation rate is as high as 400 to 600 times/min, so the molten pool vibrates at a high rate due to the arc, and defects such as weld blowholes are less likely to occur. effective.
Further, the number of oscillations mentioned above is two to three times faster than when welding is performed by mechanically oscillating the welding wire.

In the above embodiment, if the tooth profile is set such that α=0, the portion m of the bent welding wire 10 will be parallel to the side wall, and therefore the arc oscillation will once completely stop at the side wall.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the state of narrow gap arc welding, FIG. 2 is an explanatory diagram of the welding wire feeding device according to the present invention, and FIG. 3 is a sectional view of a weld bead using a conventional straight welding wire. FIG. 4 is a sectional view of a weld bead when the welding wire feeding device according to the present invention is used. In the drawing, 7 and 8 are gears, 9 is a welding wire, and 10
is the welding wire after bending.

Claims (1)

[Scope of utility model registration request] A pair of gears with triangular tooth profiles that mesh with a distance that allows the welding wire to be caught, are provided so that the tips and roots of the teeth match and rotate synchronously, and the welding wire is fed out with a bend. A welding wire feeding device characterized in that a flat portion is provided at the tip and base of the teeth.