JPS6025336Y2 - arctic - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transition type arc torch that generates a plasma arc between a non-consumable electrode in a nozzle and a workpiece.

As shown in FIG. 1, this type of arc torch generally has a gas flow path 4 for forming plasma between an arc constriction nozzle 2 attached to an anode body 1 and a non-consumable electrode 3 (cathode). A plasma arc a serving as a heat source is generated between the non-consumable electrode 3 and the workpiece 5 by supplying working gas from a working gas supply source (not shown) to the gas flow path 4. ing.

Note that 6 is an insulating cylinder that covers the anode main body 1 and the nozzle 2 from the periphery thereof.

When this type of arc torch is used for cutting work, the nozzle 2 at the tip of the torch and the workpiece 5 may often be connected to each other due to molten material scattered from the cutting section.

When such a phenomenon occurs, the workpiece 5 and the nozzle 2 are short-circuited due to the conductive melt, and the arc moves to the nozzle 2 side, which is closer to the non-consumable electrode 3 than the workpiece 5, and is cut. There was a risk that this would not only reduce performance but also cause damage to the nozzle itself.

Further, the above-mentioned torch is generally constructed such that the tip of the nozzle 2 is exposed to the outside of the insulating cylinder 6 so that the state of arc generation can be easily seen.

Therefore, even if the operator accidentally hits the workpiece 5 with the torch, the nozzle 2 at the tip of the torch will come into contact with the workpiece 5, and the same phenomenon as described above will occur.

The present invention provides an arc torch that prevents the reduction in cutting performance and damage to the nozzle caused by electrical short circuit between the nozzle and the workpiece, which are the drawbacks of the prior art described above.

That is, in the arc torch according to the present invention, as in the embodiment shown in FIG. The diameter d is set in the relationship d≦D with respect to the outer diameter of the nozzle 9, and the tip of the insulating cylinder 8 is made to protrude by a desired amount 1 from the tip surface of the nozzle 9, thereby forming a hollow truncated cone shape. It is.

When cutting the workpiece 5, most of the melt that scatters from the cut portion falls and accumulates on the upper surface of the workpiece 5.

Although a very small portion of this melt does not fall onto the workpiece 5 and adheres to the torch side, working gas is ejected from the torch downward from the insulating tube 8 through the electrode 3 and nozzle 9. Therefore, intrusion of molten material into the insulating cylinder 8 can be prevented to some extent.

In the present invention, the tip of the insulating tube 8 is shaped like a hollow truncated cone, and a space X is defined on three sides by the inner circumferential surface of the insulating tube 8, the tip of the anode 7, and the outer circumferential surface of the nozzle 9. Since it was formed,
Even if the molten material leaks from the tip hole (diameter d) of the insulating tube 8,
Even if the melt falls into the nozzle 9, it will adhere to the flat part formed at the tip of the nozzle 9.

Since the space X is located at the rear of the nozzle 9, the melt is blocked by the nozzle 9, so it is extremely rare for the melt to enter the space X.

Fig. 3 shows the state in which a hole is cut into an aluminum material on a test basis using the arc torch of the present invention shown in Fig. 2, and the test conditions at this time are a plasma arc current of 150 A, a working gas Argon gas) 13/ /
The arc length was set to 5 Mn.

The reason why the above-mentioned aluminum material was used as the test material is that compared to stainless steel or mild steel, it causes more molten material to scatter and is more likely to adhere.

Under the above conditions, Anai repeated the test, and as a result, around the 30th test, the scattered molten material 10 extended from the tip of the insulating cylinder 8 onto the workpiece 5, as shown in FIG. 3, resulting in a short circuit.

At this time, a small amount of scattered molten material 10 was also observed in the space X between the insulating tube 8 and the nozzle 9, but no arc disturbance or damage to the nozzle 9 that would adversely affect cutting performance was observed. There wasn't.

However, during the cutting operation, the operator must not leave the scattered molten material 10 on the tip of the insulating cylinder 8 until it becomes elongated into an icicle shape as shown in FIG. 3 and short-circuits with the workpiece 5. Instead, use a hard tool, etc. to remove the scattered molten material that has adhered to the insulating tube 8 as appropriate (at a time when the bulge at the tip of the insulating cylinder 8 is noticeable even if it is small, or at regular intervals in a planned manner). However, it is not necessary to clean the space X so frequently.

As described above, according to the present invention, a space is provided between the insulating cylinder and the nozzle that constitute the arc torch, and the hole diameter at the tip of the insulating cylinder is made smaller than the outer diameter of the nozzle.
Most of the molten material that scatters radially from the welding part adheres to the tip surface of the insulating tube, and most of the molten material that has entered the inside of the insulating tube adheres to the tip surface of the nozzle, so the inner peripheral surface of the insulating tube Since there is very little molten material adhering to the space, and very rarely molten material adhering to the space, the space ensures insulation between the nozzle and the insulating tube, and maintains stable plasma arc generation. I can do it.

Furthermore, even if the torch hits the workpiece, it will not cause an electrical short circuit, so manual torches can ensure safety.

Furthermore, since the insulating tube tip surface protrudes from the nozzle tip surface and is constricted, the shielding effect can be enhanced when shielding gas flows.

[Brief explanation of the drawing]

Figure 1 is a longitudinal cross-sectional view showing the tip of a conventional arc torch;
FIG. 2 is a longitudinal cross-sectional view showing the tip of the arc torch of the present invention, and FIG. 3 is a diagram showing a state in which a hole is cut using the arc torch of FIG. 3...Non-consumable electrode, 4...Gas flow path, 5...Work material, 7...Anode body,
Death: Insulating tube, 9: Nozzle, X...
...Space department.

Claims (1)

[Scope of utility model registration request] It consists of a cylindrical body that surrounds a non-consumable electrode from its periphery to form a gas flow path, an arc constriction nozzle attached to the cylindrical body, and an insulating tube that covers the body and the nozzle from the periphery. In an arc torch in which the diameter of the hole at the tip of the insulating tube is smaller than that of the outer circumferential surface, a hole is formed between the outer circumferential surface of the nozzle and the inner circumferential surface of the insulating tube, and between the tip surface of the nozzle and the tip surface of the insulating tube. An arc torch characterized in that a cylindrical space is formed extending from the space toward the distal end surface of the main body.