JPS6056595B2 - welding equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding device using a consumable electrode wire (hereinafter referred to as wire), and more specifically, its purpose is to stabilize the wire feeding and stabilize the welding arc.
Furthermore, it is an object of the present invention to provide a welding device having a long torch cable.

First, the conventional structure of this type of welding device will be explained with reference to the drawing in FIG.

In FIG. 1, 1 is a wire reel, and a wire 2 wound around the wire reel 1 is moved into a flexible wire guide tube (hereinafter referred to as a wire guide tube) by a wire feed roller 4 connected to the shaft of a motor 3. 5, the torch body 6 and the contact tip 7, and are supplied to the welding arc portion 9 generated between the wire 2 and the workpiece 8. The welding current supplied by the welding transformer is transmitted to the flexible conductor 10, and is passed through the conductive torch body 6 mechanically coupled to the flexible conductor 10 and fastened to the torch body 6 by screwing, etc. Electricity is applied to the wire 2 from the contact tip 7, which has an inner diameter slightly larger than the diameter of the wire 2 connected to the contact tip 7. Here, the flexible conductor 10 and the wire guide tube 5 constitute a torch cable, and the latter is usually constructed so that it can be inserted into the former. By the way, in this kind of conventional welding equipment, the torch cable length is usually about 3 m, and when welding, the torch cable is almost never in a straight line, and usually has a certain bend. There is wire 2
The load due to frictional resistance when the wire passes through the wire guide tube 5 occupies a considerable proportion when viewed from the wire guide tube 5, the torch body 6, and the contact tip 7 as a whole, and sometimes the wire feeding becomes unstable, resulting in welding arc. This caused problems such as unstable welding, resulting in uneven welding and defects.

Furthermore, for this reason, the length of the torch cable is limited to approximately 3 m or less, except in special cases such as when the torch cable is fixed in a straight line. It was very inconvenient that the service was limited to within a radius of about 3 meters. The present invention is intended to eliminate such conventional drawbacks, and is as follows:
This will be explained using FIGS. 2 to 6. First, the wire 2 acts as a very long column inside the wire guide tube 5, and even if a slight load is applied to this column,
It has been found to form a series of short arcuate sections as shown in the figure.

This arcuate portion presses against the inner wall of the wire guide tube 5 and therefore creates a strong frictional resistance in this portion. As shown by comparing FIGS. 2 and 3, this frictional resistance force decreases as the inner diameter of the wire guide tube 5 decreases, that is, as the gap between the inner wall of the wire guide tube 5 and the wire 2 decreases. it is obvious. Figure 4 shows the results of a test to investigate the wire feeding force for the wire guide tubes shown in the following table.The vertical axis is the wire feeding force, the horizontal axis is the torch cable length, and the inner diameter of the wire guide tube 5 is plotted. It is a diagram expressed in terms of parameters.
Here, the wire feeding force means that the wire 2 is fed with a certain force by the wire feeding roller 4 (25 kg in Fig. 4).
) The wire 2 was fed into the wire guide tube 5 and the ejection force of the wire 2 coming out from the contact tip 7 at this time was measured. In FIG. 4, line A indicates the minimum wire feeding force necessary to obtain stable wire feeding. Further, the shape of the torch cable has a radius of curvature of 150R and a bending angle of 720. As is clear from FIG. 4, the wire guide tube 5 used conventionally, that is, the wire 2
In order to reduce the mere contact resistance when the wire guide tube 5 passes through the wire guide tube 5, the inner diameter of the wire guide tube 5 is set to 40% of the diameter of the wire 2.
When using a wire guide tube 5 larger than this, the wire feeding force is considerably lower than when using a wire guide tube 5 whose inner diameter is 5 to 40% larger than the diameter of the wire 2. Furthermore, when using the conventional wire guide tube 5, if the torch cable is 5 m or more and the torch cable shape has a radius of curvature of 150 R and a bending angle of 720 mm, the wire feeding force becomes very low, making stable wire feeding difficult. It turned out that I wanted to. On the other hand, when the wire guide tube 5 according to the present invention is used, even if the torch cable shape has a curvature radius of 150 R and a bending angle of 720 R, the torch cable length is stable not only from 3 to 5 m but also over 5 m. It has been found that wire feeding, ie stable welding arc, can be obtained.

Here, in the test conducted by the present inventors, a motor with a force capable of imparting a propulsive force of 25 k9 to the wire 2 at the wire feed roller portion was used. The relationship with dimensions will be explained, and furthermore, it will be explained that the propulsion force of the 25k9 is optimal.

As mentioned above, the wire 2 forms a short arcuate portion at the saw end inside the wire guide tube 5 due to a slight load, but friction when the wire 2 passes through the wire guide tube 5 due to bending of the torch cable, etc. In order to prevent the wire feeding force at the tip of the contact tip 7 from decreasing due to further increase in resistance, the driving force of the motor is improved to increase the propulsive force of the wire 2 at the entrance of the wire guide tube 5.
I will explain below.

At this moment, a large load will be applied to wire 2,
The pitch of the aforementioned arcuate portions becomes even shorter, the number of the arcuate portions increases, and furthermore, the arched portions generate a strong wedge force with the inner wall of the central tube, and finally the propulsive force of the wire 2 is reduced. It will no longer be transmitted. If the load applied to the wire 2 at the time when the wedge force is generated and the propulsion force of the wire 2 is no longer transmitted is called the limit load, the limit load point will depend on the size of the gap between the recess in the wire guide tube 5 and the wire 2. It can be easily considered that the larger the gap, the lower the limit load point, and the smaller the gap, the higher the limit load point. In other words, to put it simply, if the gap is large, even if a relatively small load is applied to the wire 2, the wire 2
forms an arcuate portion with a short pitch, causing a strong wedge force between the wire 2 and the inner wall of the central tube.Conversely, if the gap is small, even if a relatively large load is applied to the wire 2, the arcuate portion of the wire 2 If the pitch is made too short, it will be difficult for a strong wedge force to act between it and the inner wall of the center tube. In other words, in order to prevent a decrease in the wire feeding force at the tip of the contact tip 7 due to an increase in frictional resistance when the wire 2 passes through the wire guide tube 5, the motor power is increased to provide a driving force for the wire 2 at the entrance of the wire guide tube 5. It is effective to some extent to improve the wire 2, but once the wire 2 reaches the limit load point, the driving force of the motor 3 is further improved to improve the propulsive force of the wire 2 at the entrance of the wire guide tube 5. However, the driving force is no longer transmitted to the tip of the contact tip 7, and the critical load point is between the inner diameter of the wire guide tube 5 and the wire 2.
It is determined by the size of the gap between the FIG. 5 shows the relationship between the wire feeding force and the propulsive force applied to the wire for the wire guide tube in the above table. In FIG. 5, the vertical axis represents the wire feeding force, and the horizontal axis represents the wire connected to the motor 3. 5 is a diagram illustrating the propulsive force applied to the wire 2 by the feed roller 4 and using the inner diameter of the wire guide tube 5 as a parameter. FIG.

Here, line A indicates the minimum wire feeding force necessary to obtain stable wire feeding. As is clear from FIG. 5, when using the conventionally used wire guide tube 5, that is, the wire guide tube 5 whose inner diameter is 40% or more larger than the diameter of the wire 2, the wire feed roller 4 feeds the wire 2. The propulsive force is effectively transmitted up to 20 to 24 k9, but even if the propulsive force is increased beyond that, the wire feeding force hardly increases.

On the other hand, when using the wire guide tube 5 according to the present invention, that is, when using the wire guide tube 5 whose inner diameter is 5 to 40% larger than the diameter of the wire 2, the driving force is 25k9.
Even if the wire is increased even further, the propulsive force is effectively transmitted as an increase in the wire feeding force at the tip of the contact tip 7, and the wire feeding force necessary for stable wire feeding can be obtained. The present invention was discovered based on the results of such experiments, and FIG. 6 shows an embodiment of the present invention.

In FIG. 6, 1, 2, 3, 4, and 6 indicate the same parts as in FIG. 1, 11 is a torch cable, and 12 is a reinforcing member along this torch cable 11.
It is placed along the entire length of the wire or at an appropriate position from the wire feeding side. 13 connects this reinforcing member 12 to the torch cable 11
a fixing member 14 for fixing to the torch cable 11;
This is a connecting fitting attached to one end of the wire feed roller 4 for guiding the wire 2 sent from the wire feed roller 4 to the torch cable 11.

Here, the reinforcing member 12 is devised so that its rigidity changes continuously or stepwise, and is arranged so that the rigidity decreases as it approaches the tip of the torch. It is designed to prevent small bends that would impede wire feeding, while also not impairing welding workability. Further, the rigidity is determined depending on the usage condition of the torch cable 11,
If the torch cable 11 is severely bent, the rigidity can be increased, and if not, the rigidity can be decreased. Also,
In the present invention, the inner diameter of the wire guide tube inside the torch cable 11 is 5 to 40% larger than the diameter of the wire 2, and furthermore, the motor 3 can apply a propulsive force of 25k9 or more to the wire 2 at the wire feed roller 4 portion. It has driving force. According to the configuration of the present invention, the wire feeding force required at the tip of the contact tip is provided,
It is possible to maintain good wire feeding performance and always obtain a good welding arc, and it is also possible to extend the torch cable, which is normally limited to 3 m or less, contributing to improved efficiency at welding work sites. The points are very large.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the structure of a welding device, Fig. 2 is a sectional view showing the state of the wire in the conventional wire guide tube, and Fig. 3 shows the state of the wire in the wire guide pipe according to the present invention. 4 is a diagram showing the relationship between the inner diameter of the wire guide tube and the wire feeding force, and FIG. 5 is a diagram showing the relationship between the inner diameter of the wire guide tube, the wire propulsion force at the inlet of the wire guide tube, and the wire feeding force 7. , FIG. 6 is a schematic diagram showing a welding apparatus according to an embodiment of the present invention. 1...Wire reel, 2...Wire, 3
...Motor, 4...Wire feed roller,
5... Flexible wire guide tube, 6... Torch body, 11... Torch cable, 12...
...Reinforcement member.

Claims (1)

[Claims] 1. At a welding position, a consumable electrode wire wound around a wire reel is continuously supplied to a predetermined welding position through a torch cable and a torch body by a wire feed roller connected to a motor shaft, and a consumable electrode wire is inserted into the torch cable. A flexible wire guide tube is provided, the inner diameter of the flexible wire guide tube is 5 to 40% larger than the diameter of the wire, and a reinforcing member whose rigidity changes continuously or stepwise is provided on the torch cable. As you go towards the tip,
The wire is arranged along the wire so that its rigidity is reduced, and the wire propulsion force at the wire feed roller is 25 kg.
Welding equipment as described above.