JPH09202528A - Wire feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably feed a wire and to restrain damage of the front surface of the wire to the same degree or less as that of a steel roller by forming a feed roller for feeding a welding wire having the prescribed diameter to a welding torch by ceramic, and setting the opening angle of a V-groove on the outer peripheral surface to the prescribed angle. SOLUTION: A feed roller 1 of a wire supplying device is made of ceramic, V-grooves 2, 2 continuing in the circumferential direction are formed on the outer peripheral surface at a distance, and the opening angle of each V-groove 2 is in the range of 50 to 120 deg.. A welding wire 3 having the diameter in the range of 0.6 to 2.0mm is fed to a welding torch by the rotation of the feed roller 1, when one V-groove 2 is worn, the other V-groove 2 is used. In this case, if the opening angle θ is less than 50 deg., the wire front surface is easily damaged even if pressurizing force is reduced into the range required for stable supply, and common use of the feed roller 1 is made difficult. When the opening angle θ exceeds 120 deg., stable supply is made difficult, pressurizing force is unavoidably increased, and the front surface of the wire 3 is easily damaged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a welding wire used for gas shielded arc welding, and particularly has a wire diameter of 0.6.
The present invention relates to a wire feeding device used for feeding a thin wire of about 2.0 mm to a welding torch.

[0002]

2. Description of the Related Art A wire feeder used for feeding a so-called thin wire having a wire diameter of 0.6 to 2.0 mm has a structure in which a feed roller and a pressure roller are combined. The feed roller has a V-groove on the entire outer surface, and the welding wire pushed into the V-groove by the pressure roller is fed to the welding torch by its own rotational drive.

Steel rollers are widely used as the feed roller and the pressure roller. The opening angle of the V groove in the steel feed roller is set as narrow as around 40 ° in order to prevent feeding failure due to wire slip. However, in the steel roller, especially in the feed roller thereof, the V groove is abraded so that frequent roll conversion is unavoidable, resulting in an increase in the roll unit.

A ceramic feed roller has been developed against the background of such circumstances. Although the feed roller made of ceramics has a higher unit price than the roller made of steel, its wear resistance is remarkably excellent, and as a result, it is expected that the unit consumption of rolls will be reduced. However, the amount used has not grown as expected from its performance. The reason is considered as follows.

[0005]

First, a feed roller is required for each wire size, and the number of rollers is large, so the introduction cost is very high. Secondly, the surface of the wire is easily scratched. If the surface of the wire is flawed, the chip will be prematurely worn and the arc will be unstable. In order to prevent wire flaws, it is considered effective to reduce the applied pressure as compared with the case of steel rollers, but it is still more likely to have flaws than steel rollers, and when the applied pressure is reduced to the extent that there are no flaws, Poor wire feeding occurs.

The opening angle of the V groove in the ceramic feed roller is set to about 40 °, like the steel roller.

The object of the present invention is to suppress the damage of the wire surface to the same level as that of the steel roller or less, and to reduce the roller introduction cost, although the wire is stably fed using the ceramic feed roller. An object of the present invention is to provide a wire feeding device that enables a significant reduction.

[0008]

In the wire feeder of the present invention, a feed roller for feeding a welding wire having a wire diameter of 0.6 to 2.0 mm to a welding torch is made of ceramics, and a feed roller is provided. The structural feature is that the opening angle of the V-shaped wire fitting groove formed on the outer peripheral surface of the roller is 50 to 120 °. In the following description, the V-shaped wire fitting groove is simply referred to as a V groove.

In a ceramic feed roller, the opening angle of the V groove formed on the outer peripheral surface of the feed roller is 50 to 12
By increasing the angle to 0 °, damage to the wire surface can be suppressed while stably supplying the wire. Further, the feed roller can be shared between the wires having different outer diameters, and the introduction cost can be reduced by half.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view showing the roll constitution of an example of the wire feeding apparatus of the present invention. Feed roller 1
Is made of ceramics. V-grooves 2 and 2 which are continuous in the circumferential direction are formed on the outer peripheral surface thereof at intervals in the roll axial direction 1. The opening angle θ of the V groove 2 is 50 to 120 °.

The welding wire 3 is pushed by the pressure roller 4 and fitted into the one V groove 2, and is fed to the welding torch by the rotation of the feed roller 1. When one V-groove 2 is worn,
The feed roller 1 is replaced and the other V groove 2 is used.

When the welding wire is pushed by the pressure roller and the welding wire passes through the V groove, the reaction force N applied to the wall surface of the V groove is expressed by the following equation. P is a pressing force, and θ is an opening angle. N = P / 2sin 0.5θ

Here, when the friction coefficient of the wall surface of the V groove is μ, the frictional force F is expressed by F = μN, so the above equation is transformed into the following equation. F = μP / 2sin 0.5θ

From the above equation, when μ and P are constant, when the opening angle θ increases, the frictional force F decreases, and the wire flaw decreases accordingly. In the groove shape of the conventional ceramic feed roller, θ is small and μ is larger than the steel roller, so that the frictional force F becomes excessively large.

When the opening angle θ of the V groove is less than 50 °, the wire surface is likely to be flawed even if the applied pressure is reduced within the range required for stable supply. Also, it becomes difficult to share the rollers.
If it exceeds 120 °, it will be difficult to supply the wire stably.
As a result of being forced to increase the pressing force, the wire surface is likely to be flawed. A particularly desirable opening angle θ is 60 ° or more as a lower limit and 110 ° or less as an upper limit.

The depth d of the V groove must satisfy the condition of the following equation, where the opening angle is θ and the diameter of the wire to be used is D. If the depth d is smaller than this range, the wire will hit the upper edges of both sides of the V groove, and the wire will be in line contact with each other to easily cause slip. When the wire is large, the uppermost part of the wire is located below the upper edges of both sides of the V groove, and thus the pressure applied by the pressure roller does not work and the wire is not fed. Particularly desirable depth d is 1.2 times or more of the following lower limit value for the lower limit and 0.8 times or less of the following upper limit value for the upper limit. [D / 2] ・ [1 / sin0.5 θ−sin0.5θ] <d <[D / 2] ・ [1 + 1
/sin0.5θ] (where 0.6 ≤ D ≤ 2.0, 50 ° ≤ θ ≤ 120 °)

The bottom of the V groove need not be sharp at all, and can be a flat surface or a curved surface that does not contact the wire. If the bottom of the V groove is a surface, its depth d
Is a value assuming that the bottom of the V groove is sharp, that is, the depth to the intersection of the extension lines on both side surfaces of the V groove.

FIG. 2 shows the conditions of the above equation when the wire diameters are 1.2 mm and 1.4 mm. When one V-groove is shared between the wires of both sizes, the range of d that satisfies both is sufficient. For steel feed rollers,
Since both wall surfaces of the V-grooves are worn early corresponding to the wire outer shape, it is impossible to share the roller regardless of the opening angle.

The pressure roller may be a steel roller, but a ceramic roller is preferable because it is superior in wear resistance and the pressing force is stable for a long period of time, and it is particularly effective in combination with a ceramic feed roller. can do.

The components and particle sizes of the ceramics constituting the roller are not limited, but the components are Al ₂ O ₃ : 92-.
99.5% is preferable from the viewpoint of strength, and the particle size is preferably 10 μm or less from the viewpoint of surface smoothness.

[0022]

EXAMPLES Next, examples of the present invention will be described, and the effects of the present invention will be clarified by comparison with comparative examples.

A steel feed roller and a steel pressure roller having a V-groove opening angle of 40 °, and a V-groove opening angle of 40 to 130.
The degree of damage on the wire surface and the wire feedability were investigated using a ceramics feed roller and a ceramics pressure roller. The component of ceramics is Al ₂ O
₃ : 92% (some are 99.5%), particle size is 2-3μ
m.

The degree of damage on the wire surface depends on the wire diameter being 1.2.
A solid wire of mm was fed by inching, and the degree of flaw attached to the wire surface while passing through the feed roller was evaluated by the average surface roughness (Ra). Wire feedability depends on the wire diameter
Using flux-cored wire of 1.2mm and 1.4mm,
When welding was performed under the following conditions, the welding current was evaluated by the minimum pressing force that did not decrease by 30 A or more. The pressing force was divided into five levels with the minimum required pressing force in the case of a steel roller being the maximum value.

Welding current-welding voltage 1.2 mm diameter: 250-30 V, 1.4 mm diameter: 300 A-
In the middle of the load 6m cable 34V conduit cable, the load of 200mm diameter 1-turn shielding gas CO ₂ -20 liters / min

[0026]

[Table 1]

The survey results are shown in Table 1. In the case of a steel feed roller, it is not possible to use the V groove in common, so it is necessary to use a feed roller for each of the two types of wires (No. 1,
2). In the case of a ceramic feed roller as well, when the opening angle of the V groove is 40 °, two types of wires each require a feed roller, and although the minimum pressing force is as small as 2, the degree of damage to the wire surface Is remarkable (No.
3, 4). However, if the opening angle is 50 ° or more, 2
The feed roller can be shared between different types of wires, and the degree of damage to the wire surface can be suppressed (No. 5-11).

However, when the opening angle is 50 °, the wire surface is significantly damaged (No. 5) compared to when the opening angle is 60 to 110 °. When the opening angle was 120 °, the wire slipped at a pressure of 2 and the welding current decreased by 30 A or more, so the pressure was increased to 3. As a result, the average surface roughness increased (No. 10). When the opening angle was 130 °, the pressing force was increased to 4 due to the severe slip, and as a result, the average surface roughness was considerably lowered.

[0029]

As is clear from the above description, the wire feeding device of the present invention uses the ceramic feed roller and feeds the wire in a stable manner, but the wire flaw is equal to that of the steel roller. It is possible to reduce the wear of the tip and to improve the arc stability. Moreover, since the feed roller can be shared between the wires having different sizes, the number of rolls to be introduced can be reduced by half, and the introduction of the feed roller can be made very easy.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a roll configuration of an example of a wire feeding device of the present invention.

FIG. 2 is a diagram showing a range of a depth in which a V groove can be shared, with an opening angle as a parameter.

[Explanation of symbols]

 1 Feed Roller 2 V Groove (V-shaped Wire Fitting Groove) 3 Welding Wire 4 Pressure Roller

Claims (2)

[Claims] 1. A feed roller for feeding a welding wire having a wire diameter of 0.6 to 2.0 mm to a welding torch is made of ceramics, and a V-shaped wire fitting formed on the outer peripheral surface of the feed roller. The wire feeding device, wherein the opening angle of the dowel groove is 50 to 120 °. 2. The pressure roller combined with the feed roller is made of ceramics.
The wire feeder according to.