JP3205540B2 - Nozzle for plasma torch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma torch nozzle.

[0002]

2. Description of the Related Art In a plasma torch, a plasma arc is generated between an electrode portion inserted into a generally hollow conical nozzle disposed at a tip portion of a plasma torch body and a tip portion of the nozzle, and a plasma torch is formed. The working gas supplied from the main body into the nozzle is heated to a high-temperature plasma gas, and the workpiece is cut off by the plasma gas ejected at high speed from the nozzle at the tip of the nozzle due to expansion of the volume due to heat and plasma. Is what you do.

Further, in order to maintain and adjust the shape of the plasma gas ejected from the nozzle, Japanese Patent Application Laid-Open No. 7-178559 has been disclosed.
As shown in the publication, a generally hollow cone-shaped first nozzle which is disposed at the tip of the plasma torch body and in which plasma gas is jetted, covers the first nozzle, and has an ejection port of the first nozzle A second nozzle having a generally hollow conical shape in which an ejection port is formed so as to communicate with each other, and is disposed between the first and second nozzles, and the axial center of the first and second nozzles is provided. An insulator having a groove or a small hole spirally formed in a direction gives a rotation to the flow of the assist gas supplied from the plasma torch main body between the first and second nozzles, thereby providing a first rotation. A plasma torch nozzle for protecting and converging a plasma gas as a swirling flow around the plasma gas ejected from the nozzle has been proposed. In addition, the second nozzle is attached to the processing object by a high-temperature, high-speed plasma gas, the molten spray of the processing object blown up from the processing object adheres, or an arc current for generating a plasma arc is discharged from the nozzle to the processing object by the illegal current ( Consumables that are easily melted by double arcing.
In addition, since these plasma torch nozzles are heated by a plasma arc generated between the electrode portion and the nozzle, usually, water-cooled cooling is performed by circulating cooling water around or inside the nozzle to perform cooling. Means, first and second
An air-cooled cooling unit that performs cooling using an assist gas that is passed between the nozzles is used.

[0004]

Problems to be Solved by the Invention
As shown in Japanese Patent Publication No. 9 (1994), in the conventional nozzle for a plasma torch, in order to make the assist gas a swirling flow,
Although the insulator, which is a separate member from the first and second nozzles, is used, the number of parts constituting the nozzle increases, and the manufacturing cost of the nozzle increases. In order to replace the consumable second nozzle, it is necessary to frequently disassemble the nozzle. The insulator is attached to the inclined surfaces of the first and second nozzles formed in a generally hollow conical shape. Therefore, when the angles of the inclined surfaces of the first and second nozzles are small, the seating of the insulator is deteriorated, the insulator is easily shifted from a correct position, and there is a problem that the assembling work of the nozzle becomes difficult.

[0005] Further, since the first nozzle and the insulator are separate bodies, the area of the first nozzle heated by the plasma arc in contact with the assist gas is small, and the cooling efficiency by the assist gas is poor. As a result, when an air-cooling type cooling means is used as the cooling means for the first nozzle, heat is stored in the first nozzle and an arc current is directly discharged from the nozzle to the workpiece by a double arc phenomenon. Is likely to occur, and the nozzle may be damaged.

The present invention has been made in view of the above circumstances, and in a plasma torch nozzle in which a plasma gas is maintained and adjusted by an assist gas, an insulator with a poor sitting in the nozzle is omitted to assemble the nozzle. An object of the present invention is to provide a nozzle for a plasma torch which facilitates the reduction of the number of parts constituting the nozzle, simplifies the assembly of the nozzle and reduces the manufacturing cost, and increases the cooling efficiency of the nozzle. .

[0007]

According to a first aspect of the present invention, there is provided a nozzle for a plasma torch, one end of which is connected to a main body of the plasma torch. A substantially cylindrical nozzle base to which the original working gas is supplied,
A first nozzle having a substantially hollow conical shape at the other end of the nozzle base and having a first ejection port at its tip for ejecting plasma gas generated from the electrode portion, and a first nozzle. An end on the side connected to the first nozzle so as to cover the first nozzle while securing a flow space for flowing the assist gas supplied from the plasma torch main body.
One step protruding inward on the inner peripheral side of the cylindrical part near the part
The end of the first nozzle on the nozzle base side
A second thread for screwing the outer peripheral portion of the cylindrical portion formed in the vicinity, having a substantially hollow conical shape, and ejecting the plasma gas and the assist gas at a tip thereof. And a second nozzle having an ejection port of the first nozzle and a flow of the assist gas on at least one of an outer surface side of the first nozzle and an inner surface side of the second nozzle which define the circulation space. And a swirling flow applying means for imparting rotation to the swirling flow applying means, wherein the swirling flow applying means is provided in the circulation space at any one of an outer surface side of the first nozzle and an inner surface side of the second nozzle. A ring-shaped protruding step that is formed integrally with the second nozzle and blocks the flow of the assist gas toward the second ejection port of the second nozzle; To give these said 1, characterized in that it is formed by a tilted groove with an inclination angle of 60 degrees to 80 degrees with respect to the axial direction of the second nozzle.

[0008]

[0009]

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a plasma torch nozzle according to the present invention will be described below. As shown in FIG. 1, the plasma torch 1 includes a plasma torch main body 2, a plasma torch nozzle 3 inserted into a tip portion of the plasma torch main body 2, and a plasma torch nozzle 3.
Is covered with the exception of the tip portion thereof, and is screwed into the plasma torch main body 2 so that the plasma torch nozzle 3
And a nozzle holder 4 for fixing the nozzle to the tip of the plasma torch main body 2. FIG.
1A shows a state of the assembled plasma torch 1, and FIG. 1B shows a state of the plasma torch 1 when disassembled.

As shown in FIGS. 2 and 3, one end of the plasma torch nozzle 3 is hermetically inserted and connected to the tip of the plasma torch main body 2, and is connected to the plasma torch main body 2 for generating a plasma arc. A substantially cylindrical nozzle base 7 into which the electrode portion 6 is inserted and a working gas serving as a source of plasma gas is supplied, and a thick, substantially conical shape formed continuously with the other end of the nozzle base 7, A first nozzle 9 having a first ejection port 8 for ejecting a plasma gas at a tip thereof, and a flow space 1 through which an assist gas supplied from the plasma torch main body 2 flows between the first nozzle 9 and the first nozzle 9.
A second nozzle 13 which covers the first nozzle 9 while securing the first nozzle, has a substantially hollow conical shape, and has a second ejection port 12 for ejecting a plasma gas and an assist gas at a tip thereof; On the outer surface side of the first nozzle 9, a swirling flow applying means 14 for imparting a swirl to the flow of the assist gas flowing through the flow space 11 is integrally formed. I have.

As shown in FIGS. 3B and 4, the cylindrical portion 1 is located near the end of the first nozzle 9 on the nozzle base 4 side.
The outer peripheral side of the cylindrical portion 16 is formed with an external thread 17 for screwing the second nozzle 13. A ring-shaped projecting step 18 is formed integrally on the outer surface side of the inclined portion of the first nozzle 9 along the circumferential direction. Grooves 19 inclined at an angle of, for example, 70 degrees with respect to the axial direction of the first nozzle 9 are formed in the projecting step 18 at equal intervals. The providing means 14 is configured. The inclination angle of the groove 19 is determined so that the swirling and the flow rate of the assist gas are most effective for protection and adjustment of the plasma gas.
It is desirable to set each time. The protruding step 18 abuts on the inner surface of the distal end of the second nozzle 13 to prevent close contact between the outer surface of the distal end of the first nozzle 9 and the inner surface of the distal end of the second nozzle 13. A flow space 11 is formed between the tip portions of the first and second nozzles 9 and 13.

A cylindrical portion 21 is formed near the end of the second nozzle 13 on the side connected to the first nozzle 9.
An internal thread 22 is formed on the inner surface side of the end of the cylindrical portion 21 so as to project one step toward the inner surface, and is screwed to the male screw 17 formed in the first nozzle. Have been. The female screw 22 is formed shorter in the axial direction of the first and second nozzles 3 than the male screw 17 formed in the first nozzle 9. When the first and second nozzles 13 are screwed into each other, a flow space 11 is formed between the cylindrical portions 16 and 21 of the first and second nozzles 9 and 13.

On the outer peripheral side of the cylindrical portion 21 of the second nozzle 13 at a position separated by a predetermined distance from the end where the female screw 22 is formed, the nozzle holder 4 is brought into contact with the inner surface of the tip end of the nozzle holder 4. The flange 2 for preventing the second nozzle 13 from falling off from the tip of the nozzle 4 and maintaining the airtightness of this portion
3 are formed. As shown in FIG. 3A, an assist gas supplied from the plasma torch main body 2 to the outer peripheral side of the second nozzle 13 is provided between the female screw 22 and the flange 23 in the first nozzle. 9 and the second nozzle 1
A plurality of inlets 24 are formed for introduction into the circulation space 11 formed between the inlet 3 and the inlet 3. In addition, as shown in FIG. 2, the assist gas passes through an assist gas flow passage 26 formed between the nozzle holder 4 and the tip of the plasma torch main body 2, and flows toward the outer peripheral side of the second nozzle 13. Supplied.

Hereinafter, the operation of the plasma torch 1 using the plasma torch nozzle 3 configured as described above will be described. A working gas is supplied from the tip of the plasma torch body 2 into the nozzle base 7 of the plasma torch nozzle 3 and an assist gas flow passage 26 formed between the tip of the plasma torch body 2 and the nozzle holder 4.
To supply the assist gas into the flow space 11 formed between the first and second nozzles 9 and 13. The working gas supplied into the nozzle base 7 is changed into a plasma gas by a plasma arc generated between the electrode unit 6 and the first nozzle 9 and is formed in the first and second nozzles 9 and 13, respectively. Are ejected from the first and second ejection ports 8 and 12.
At the same time, the assist gas supplied into the circulation space 11 is swirled by the swirling flow applying means 14 formed on the outer surface side of the first nozzle 9 in the second nozzle 1.
3, and a swirling flow is formed around the plasma gas ejected from the second ejection port 12.

According to the plasma torch nozzle 3 in the above embodiment, since the projecting step 18 is formed integrally on the outer surface side of the first nozzle, the time for separately producing the above-mentioned insulator is eliminated. In addition, the number of components constituting the plasma torch nozzle 3 can be reduced. In addition, the elimination of the insulator facilitates the assembly of the plasma torch nozzle 3. In addition, the first nozzle 9
The projection step 18 is formed integrally with the
The surface area of the nozzle 9 increases, and the cooling efficiency by the assist gas can be increased.

In the above-described embodiment, the example in which the swirling flow applying means 14 is integrally formed on the outer surface side of the first nozzle 9 is used, but the present invention is not limited to this. May be formed integrally on the inner surface side . Also,
In the above embodiment, the example in which the groove 19 of the swirling flow applying means 14 is formed counterclockwise is used. However, the present invention is not limited to this, and the groove 19 may rotate the assist gas in the same direction as the rotation generated in the plasma gas. In order to more effectively converge the plasma gas by orienting, it may be formed on either the left or right side. Further, in the above-described embodiment, an example in which the groove 19 is formed to be inclined by 70 degrees with respect to the axis of the first and second nozzles 9 and 13 is used, but the present invention is not limited to this. In order to facilitate the formation, the first and second nozzles 9 and 13 may be formed spirally with respect to the axial direction.

[0018]

Effects of the Invention] According to the nozzle for a plasma torch according to claim 1, swirling flow imparting means is a first, since it is integrally formed on one of the second nozzles, separate the insulator described above There is no need to make it, and the number of components constituting the plasma torch nozzle can be reduced.
By omitting the insulator, these first,
The assembly of the second nozzle is facilitated.

Further , a projecting step is integrally formed with the first nozzle.
If formed, the surface area of the first nozzle is increased, and the cooling efficiency by the assist gas can be increased.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a mode of use of a plasma torch nozzle according to an embodiment of the present invention.

FIG. 2 is a side view showing a configuration and a structure of a plasma torch nozzle according to an embodiment of the present invention.

FIG. 3 is a side view showing a configuration and a structure of a plasma torch nozzle according to an embodiment of the present invention.

FIG. 4 is a perspective view showing a configuration and a structure of a plasma torch nozzle according to an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Plasma torch 2 Plasma torch main body 3 Plasma torch nozzle 4 Nozzle holder 6 Electrode part 7 Nozzle base 8 First ejection port 9 First nozzle 11 Flow space 12 Second ejection port 13 Second nozzle 14 Applying swirling flow Means 17 Male thread 18 Projection step (Swirl flow applying means) 19 Groove (Swirl flow applying means) 22 Female thread 23 Flange 26 Assist gas flow passage

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-9-47877 (JP, A) JP-A-62-28084 (JP, A) JP-A-2-217173 (JP, A) JP-A 63-28073 224877 (JP, A) JP-A-4-206399 (JP, A) JP-A-7-32156 (JP, A) JP-A-3-174980 (JP, A) JP-B-54-10534 (JP, B1) JK 4-9097 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 10/00 H05H 1/34

Claims (1)

(57) [Claims] 1. One end is connected to a plasma torch main body,
An electrode part for plasma arc generation is inserted from the plasma torch body, and a substantially cylindrical nozzle base to which a working gas serving as a source of plasma gas is supplied, and a substantially hollow cone shape is provided at the other end of the nozzle base. A first nozzle having a first ejection port formed at a tip thereof for ejecting plasma gas generated from the electrode portion, and an assist gas supplied from the plasma torch main body flowing between the first nozzle and the first nozzle covering the first nozzle while ensuring the circulation space to
So that the cylinder near the end connected to the one nozzle
The screw is formed by projecting one step toward the inside on the inner peripheral side.
Is formed near the end of the first nozzle on the nozzle base side.
A second cylindrical hole that is screwed to an external thread of the outer peripheral portion of the cylindrical portion, has a substantially hollow conical shape, and has a second ejection port at its tip for ejecting the plasma gas and the assist gas. And at least one of an outer surface side of the first nozzle or an inner surface side of the second nozzle that defines the flow space,
A swirl flow applying means for imparting rotation to the flow of the assist gas is integrally formed, and the swirl flow applying means is provided in the circulation space on an outer surface side of the first nozzle or an inner surface side of the second nozzle. A ring-shaped protruding step formed integrally with any one of the second nozzles to block the flow of the assist gas toward the second ejection port of the second nozzle; Characterized by being formed by grooves inclined at an inclination angle of 60 to 80 degrees with respect to the axial direction of the first and second nozzles in order to impart rotation to the flow of the plasma torch. nozzle.