JP6910116B2 - Manufacturing method of insulation guide for plasma torch - Google Patents

Description

The present invention relates to an insulating guide and a replacement component unit used in a plasma torch for plasma cutting.

For example, as shown in Patent Document 1, the plasma torch has an electrode as a generation point of an arc and a nozzle arranged so as to cover the electrode. The electrodes are attached to the electrode pedestal of the torch body. The insulation guide positions the nozzle so that it is concentric with the electrodes. The plasma torch generates a plasma arc between the electrode and the workpiece through the orifice of the nozzle.

Japanese Unexamined Patent Publication No. 2001-47247

The insulation guide is formed of an insulator to ensure the insulation between the electrode and the nozzle. The insulation guide is a component that positions the electrode and the nozzle. In addition, a gas passage is formed in the insulation guide. The concentricity between the electrodes and the nozzle and the plasma gas flow through the gas passage affect the quality of plasma cutting. Therefore, the insulation guide is a high-precision component that requires high-precision machining. Therefore, as the material of the insulation guide, it is preferable to use a resin material such as fine ceramics that can be cut or engineering plastic having heat resistance.

Ceramics have excellent heat resistance, but are expensive. Therefore, in order to reduce costs, it is desirable to use a resin material as the material for the insulation guide. However, if a resin insulating guide is used in the plasma torch for plasma cutting, the insulating guide may suddenly burn out. Therefore, in practice, there is a problem that it is difficult to use a resin insulating guide for the plasma torch for plasma cutting.

An object of the present invention is to suppress sudden burning of a resin insulating guide in a plasma torch for plasma cutting.

The insulating guide according to the first aspect is used for a plasma torch for plasma cutting having an electrode and a nozzle into which the electrode is inserted, and connects the electrode and the nozzle. The insulating guide includes a first inner peripheral surface, a second inner peripheral surface, and a continuous passage. The second inner peripheral surface has an inner diameter smaller than that of the first inner peripheral surface. The communication passage connects the space inside the first inner peripheral surface with the outside. The resin guide is made of injection molded resin. The first inner peripheral surface has a reflectance of 10% or more.

The plasma torch replacement component unit according to the second aspect includes an electrode, an insulating guide, and a nozzle. The electrodes are inserted into the nozzle. The insulation guide is arranged between the nozzle and the electrode, and connects the nozzle and the electrode. The insulation guide is made of injection molded resin. The inner peripheral surface of the insulating guide has a reflectance of 10% or more.

According to the present invention, in a plasma torch for plasma cutting, it is possible to suppress sudden burning of a resin insulating guide.

It is sectional drawing along the central axis of the plasma torch which concerns on 1st Embodiment. It is an exploded view of a plasma torch. It is a side view of a replacement part unit. It is sectional drawing along the central axis of a replacement part unit. It is a perspective view of an electrode. It is a perspective view of an electrode. It is sectional drawing of an electrode. It is a perspective view of the insulation guide. It is a perspective view of the insulation guide. It is sectional drawing of the insulation guide. It is the figure which looked at the insulation guide from the base end side. It is sectional drawing of the insulation guide including the axis of the communication passage. It is a perspective view of a nozzle. It is a perspective view of a nozzle. It is sectional drawing of a nozzle. It is a perspective view of the insulation ring. It is a perspective view of the insulation ring. It is sectional drawing of the insulation ring. It is a perspective view of a shield cap. It is a perspective view of a shield cap. It is sectional drawing of the shield cap. FIG. 21 is a cross-sectional view taken along the line AA of FIG. It is a perspective view of a center pipe. It is a perspective view of a center pipe. It is sectional drawing of a center pipe. It is a perspective view of a pipe body. It is a perspective view of a contactor. It is the figure which looked at the contactor from the axial direction. It is an enlarged view of the structure of the replacement part unit and its surroundings in FIG. It is a cross-sectional view different from FIG. 1 along the central axis of the plasma torch. FIG. 30 is an enlarged view of a configuration of a replacement component unit and its surroundings in FIG. 30. It is sectional drawing along the central axis of the plasma torch which concerns on 2nd Embodiment. It is sectional drawing of the replacement part unit which concerns on 2nd Embodiment. It is a perspective view of the replacement part unit which concerns on 2nd Embodiment. It is a perspective view of the replacement part unit which concerns on 2nd Embodiment. It is a perspective view of the nozzle which concerns on 2nd Embodiment. It is a perspective view of the nozzle which concerns on 2nd Embodiment. It is sectional drawing along the central axis of the plasma torch which concerns on another embodiment. It is sectional drawing of the nozzle which concerns on 1st modification. It is sectional drawing of the nozzle which concerns on 2nd modification.

1. 1. First Embodiment 1.1 Configuration of Plasma Torch Hereinafter, the plasma torch according to the embodiment will be described with reference to the drawings. FIG. 1 is a cross-sectional view taken along the central axis of the plasma torch 1a according to the first embodiment. FIG. 2 is an exploded view of the plasma torch 1a.

As shown in FIG. 2, the plasma torch 1a has a replacement part unit 2a, a torch main body 3, a first retainer cap 4, and a second retainer cap 5. The replacement part unit 2a, the first retainer cap 4, and the second retainer cap 5 are arranged concentrically with the central axis of the torch body 3.

As shown in FIG. 1, the replacement part unit 2a is attached to the torch body 3. The replacement component unit 2a has an electrode 6, an insulating guide 7, a nozzle 8, an insulating ring 9, and a shield cap 10. The replacement part unit 2a will be described in detail later.

The torch body 3 is attached to the connecting pipe 32. The torch body 3 has a base portion 33, an electrode pedestal 34, a center pipe 20, a nozzle pedestal 36, an insulating sleeve 37, and a holder 38. The base portion 33, the electrode pedestal 34, the center pipe 20, the nozzle pedestal 36, the insulating sleeve 37, and the holder 38 are arranged concentrically with the central axis of the torch body 3.

The base portion 33 has a cylindrical shape. The base portion 33 is made of a conductor. The center pipe 20, the electrode pedestal 34, and the insulating sleeve 37 are inserted into the holes of the base portion 33. The electrode pedestal 34 has a circular tubular shape. The electrode pedestal 34 is made of a conductor. The base portion 33 is electrically connected to a cable from a power source (not shown).

The center pipe 20 is inserted into the hole of the electrode pedestal 34. The center pipe 20 has a tubular shape. The center pipe 20 is made of a conductor. The tip of the center pipe 20 projects from the tip of the nozzle pedestal 36. The center pipe 20 will be described in detail later.

The insulating sleeve 37 has a circular tubular shape. The insulating sleeve 37 is made of an insulator. A part of the insulating sleeve 37 is arranged in the hole of the base portion 33. The insulating sleeve 37 is located between the electrode pedestal 34 and the nozzle pedestal 36.

The nozzle pedestal 36 has a circular tubular shape. The tip of the nozzle pedestal 36 has a tapered shape. The nozzle pedestal 36 is made of an insulator. A contactor (not shown) that makes electrical contact with the nozzle is attached to the nozzle pedestal 36. The contacts are electrically connected to the cable from the power supply. The base portion 33 is inserted into the hole of the nozzle pedestal 36. The insulating sleeve 37 is inserted into the hole of the nozzle pedestal 36. The tip of the insulating sleeve 37 protrudes from the base 33 and is arranged in the hole of the nozzle pedestal 36.

The holder 38 has a circular tubular shape. The holder 38 is attached to the connecting pipe 32 by means such as adhesion. The nozzle pedestal 36 is inserted into the hole of the holder 38. The tip of the nozzle pedestal 36 projects from the holder 38.

The first retainer cap 4 has a cylindrical shape with a tapered tip. The first retainer cap 4 is attached to the torch body 3 so as to cover the nozzle pedestal 36. The tip of the first retainer cap 4 has an opening 41 into which the shield cap 10 is inserted. The holder 38 and the nozzle pedestal 36 are arranged in the first retainer cap 4. A male screw portion 311 is provided on the outer peripheral surface of the holder 38. A female screw portion 42 is provided on the inner peripheral surface of the base end portion of the first retainer cap 4. The first retainer cap 4 is attached to the torch body 3 by screwing the male screw portion 311 of the holder 38 into the female screw portion 42 of the first retainer cap 4.

The second retainer cap 5 has a cylindrical shape with a tapered tip. The tip of the second retainer cap 5 has an opening 51 into which the shield cap 10 is inserted. The second retainer cap 5 is attached to the first retainer cap 4 so as to cover the first retainer cap 4. The first retainer cap 4 is arranged in the second retainer cap 5. The first retainer cap 4 and the second retainer cap 5 hold and sandwich the replacement part unit 2a. An O-ring R1 is arranged on the outer peripheral surface of the first retainer cap 4. A male screw 401 is provided on the outer peripheral surface of the first retainer cap 4, and a female screw 501 is provided on the inner peripheral surface of the second retainer cap 5. The second retainer cap 5 is attached to the first retainer cap 4 by screwing the male screw 401 of the first retainer cap 4 and the female screw 501 of the second retainer cap 5.

1.2 Configuration of the replacement component unit Next, the replacement component unit 2a will be described. FIG. 3 is a side view of the replacement part unit 2a. FIG. 4 is a cross-sectional view taken along the central axis of the replacement component unit 2a.

As shown in FIGS. 3 and 4, the replacement component unit 2a has an electrode 6, an insulating guide 7, a nozzle 8, an insulating ring 9, and a shield cap 10 integrated by press fitting. The electrode 6, the insulating guide 7, the nozzle 8, the insulating ring 9, and the shield cap 10 are arranged concentrically with each other. Since the replacement component unit 2a is arranged concentrically with the central axis of the torch body 3, the axes of the electrode 6, the insulating guide 7, the nozzle 8, the insulating ring 9, and the shield cap 10 are the axes of the torch body 3. Aligns with the central axis.

5 and 6 are perspective views of the electrode 6. FIG. 7 is a cross-sectional view of the electrode 6. As shown in FIGS. 5 to 6, the electrode 6 has a cylindrical shape. The electrode 6 is made of a conductor. The electrode 6 has an electrode body portion 61, a joint portion 62, and a flange portion 63.

The electrode body 61 includes the tip of the electrode 6. A heat-resistant insert 64 is embedded in the center of the tip surface 602 of the electrode 6. The heat resistant insert 64 is made of, for example, hafnium. However, a material other than hafnium may be used as the heat-resistant insert 64. As shown in FIG. 4, a part of the electrode main body 61 is arranged in the hole of the insulating guide 7. The tip of the electrode body 61 projects from the insulation guide 7. The tip of the electrode body 61 has a tapered shape.

The joint portion 62 is located on the proximal end side of the electrode main body portion 61. The joint portion 62 is located between the electrode main body portion 61 and the flange portion 63 in the axial direction of the electrode 6. The joint portion 62 is joined to the insulating guide 7 by press fitting. Therefore, the joint 62 is joined to the insulating guide 7 so as to seal the fluid without an O-ring.

The outer peripheral surface of the joint portion 62 has an uneven shape that engages with the inner peripheral surface of the insulating guide 7. Specifically, the joint 62 has a convex 621. The convex portion 621 protrudes from the outer peripheral surface of the joint portion 62. The convex portion 621 extends in the circumferential direction of the joint portion 62.

The flange portion 63 is located on the proximal end side of the joint portion 62. The flange portion 63 includes the base end of the electrode 6. The flange portion 63 has a larger outer diameter than the joint portion 62. The flange portion 63 is longer than the joint portion 62 in the axial direction of the electrode 6. The outer peripheral surface of the flange portion 63 extends in the axial direction of the electrode 6. The outer peripheral surface of the flange portion 63 has a flat shape with no unevenness in a cross-sectional view. The base end of the outer peripheral surface of the flange portion 63 is chamfered. A step portion 66 is provided between the flange portion 63 and the joint portion 62. The step portion 66 is a plane perpendicular to the axial direction of the electrode 6.

The electrode 6 has an internal passage 65. The center pipe 20 shown in FIG. 1 is inserted into the internal passage 65. The base end surface 601 of the electrode 6 is provided with an inlet of the internal passage 65. The internal passage 65 extends from the base end surface 601 of the electrode 6 toward the tip end along the axial direction of the electrode 6. A convex portion 67 is provided on the internal passage 65 side of the tip of the electrode 6. The heat-resistant insert 64 described above is arranged in the convex portion 67. With the replacement part unit 2a attached to the torch body 3, a part of the convex portion 67 is arranged in the cooling water channel of the center pipe 20.

The inner peripheral surface of the inner passage 65 has a straight portion 651 and a tapered portion 652. The straight line portion 651 extends parallel to the axial direction of the electrode 6. The tapered portion 652 expands radially toward the entrance of the internal passage 65.

Next, the insulation guide 7 will be described. 8 and 9 are perspective views of the insulation guide 7. FIG. 10 is a cross-sectional view of the insulation guide 7. The insulation guide 7 electrically insulates the electrode 6 and the nozzle 8 and connects the electrode 6 and the nozzle 8. The insulation guide 7 positions the electrode 6 and the nozzle 8 with each other in the axial direction and the radial direction.

The insulating guide 7 has a tubular shape. The insulation guide 7 is made of an insulator. The insulation guide 7 has a hole 706 into which the electrode 6 is inserted. The hole 706 of the insulation guide 7 penetrates the insulation guide 7 in the axial direction of the insulation guide 7.

The insulating guide 7 is made of a material having an elastic modulus smaller than that of ceramic. In the present embodiment, the insulation guide 7 is made of a resin such as engineering plastic. Specifically, the insulation guide 7 is made of a resin having a continuous use temperature of 100 ° C. or higher. Further, the continuous use temperature is preferably 300 ° C. or lower.

The resin guide 7 is made of a resin having a light reflectance of 10% or more. The resin guide 7 is made of a resin having a color having a brightness of 4 or more. The resin guide 7 preferably has a color having a reflectance of 30% or more, such as white, beige, or gray. For example, the insulation guide is made of uncolored polyphenylene sulfide resin (PPS). Alternatively, the insulating guide may be formed of a PPS resin colored as described above. Alternatively, the resin guide 7 may be formed of a resin other than the PPS resin.

The resin guide 7 is formed by injection molding. In that case, the steps of manufacturing the resin guide 7 include a step of melting the above-mentioned resin, a step of injecting the melted resin into the mold, and a step of solidifying the resin in the mold to obtain the above-mentioned resin guide 7. And have. After removing the resin guide 7 from the mold, a part of the shape of the resin guide 7 may be formed by machining.

As shown in FIG. 10, the inner peripheral surface of the insulating guide 7 has a first inner peripheral surface 71, an inner step portion 72, and a second inner peripheral surface 73. The first inner peripheral surface 71 extends in the axial direction of the insulating guide 7 and reaches the tip surface 701 of the insulating guide 7. The first inner peripheral surface 71 has a larger inner diameter than the second inner peripheral surface 73. The first inner peripheral surface 71 faces the outer peripheral surface of the electrode main body 61 with a gap. As will be described later, the first inner peripheral surface 71 forms a gas passage between the first inner peripheral surface 71 and the outer peripheral surface of the electrode main body 61. The inner diameter of the first inner peripheral surface 71 is substantially the same as the inner diameter of the nozzle 8. Therefore, the inner diameter of the gas passage between the first inner peripheral surface 71 and the electrode 6 is substantially the same as the inner diameter of the nozzle 8.

The inner step portion 72 is located on the proximal end side of the first inner peripheral surface 71. The inner step portion 72 is located between the first inner peripheral surface 71 and the second inner peripheral surface 73 in the axial direction of the insulating guide 7. The inner step portion 72 is inclined with respect to the axial direction of the insulating guide 7 so as to expand in the radial direction toward the tip side.

A heat-resistant coating 707 is formed on the first inner peripheral surface 71 and the inner step portion 72. The heat-resistant coating 707 is made of a ceramic material. The heat-resistant coating 707 is formed of, for example, boron nitride. However, the heat-resistant coating 707 may be formed of a ceramic material other than boron nitride. Alternatively, the heat-resistant coating 707 may be formed of a heat-resistant material other than the ceramic-based material. Alternatively, the heat-resistant coating 707 may be omitted.

The second inner peripheral surface 73 is located on the proximal end side of the inner step portion 72. The second inner peripheral surface 73 extends in the axial direction of the insulating guide 7 and reaches the base end surface 702 of the insulating guide 7. The second inner peripheral surface 73 has a first joint portion 74. The first joint portion 74 is joined to the joint portion 62 of the electrode 6 by press fitting. Therefore, the first joint portion 74 of the insulation guide 7 is joined to the electrode 6 so as to seal the fluid without the O-ring.

As shown in FIG. 4, the first joint portion 74 of the insulation guide 7 is joined to the joint portion 62 of the electrode 6, so that the electrode 6 and the insulation guide 7 are positioned with each other in the radial direction. Further, the base end surface 702 of the insulating guide 7 comes into contact with the stepped portion 66 of the flange portion 63 of the electrode 6, so that the electrode 6 and the insulating guide 7 are positioned with each other in the axial direction.

The first joint portion 74 has an uneven shape that is locked to the outer peripheral surface of the electrode 6. Specifically, the first joint 74 has a convex portion 741. The convex portion 741 protrudes from the second inner peripheral surface 73. The convex portion 741 extends in the circumferential direction of the second inner peripheral surface 73. The convex portion 741 of the first joint portion 74 of the insulation guide 7 is locked to the convex portion 621 of the joint portion 62 of the electrode 6. As a result, the insulating guide 7 is firmly prevented from coming off with respect to the electrode 6.

The outer peripheral surface of the insulating guide 7 has a first outer peripheral surface 75, a second outer peripheral surface 76, and a third outer peripheral surface 77. The first outer peripheral surface 75 extends in the axial direction of the insulating guide 7 and reaches the tip surface 701 of the insulating guide 7. The first outer peripheral surface 75 is arranged in the first hole 811 of the nozzle 8. The first outer peripheral surface 75 has a second joint portion 78. The second joint portion 78 is joined to the inner peripheral surface of the nozzle 8 by press fitting. Therefore, the second joint 78 of the insulation guide 7 is joined to the nozzle 8 so as to seal the fluid without the O-ring.

The second joint portion 78 of the insulation guide 7 has an uneven shape that locks on the inner peripheral surface of the nozzle 8. Specifically, the second joint 78 of the insulation guide 7 has a convex 781. The convex portion 781 projects from the first outer peripheral surface 75. The convex portion 781 extends in the circumferential direction of the first outer peripheral surface 75.

The second outer peripheral surface 76 is located on the proximal end side of the first outer peripheral surface 75. The second outer peripheral surface 76 extends in the axial direction of the insulating guide 7. The second outer peripheral surface 76 has a flat shape with no unevenness in a cross-sectional view. The second outer peripheral surface 76 is arranged between the first outer peripheral surface 75 and the third outer peripheral surface 77 in the axial direction of the insulating guide 7. The second outer peripheral surface 76 is arranged outside the nozzle 8. The second outer peripheral surface 76 has an outer diameter smaller than that of the first outer peripheral surface 75. In other words, the outer diameter of the first outer peripheral surface 75 is larger than the outer diameter of the second outer peripheral surface 76. In the axial direction of the insulation guide 7, the first outer peripheral surface 75 is shorter than the second outer peripheral surface 76.

The third outer peripheral surface 77 is located on the proximal end side of the second outer peripheral surface 76. The third outer peripheral surface 77 has an outer diameter smaller than that of the second outer peripheral surface 76. The third outer peripheral surface 77 extends in the axial direction of the insulating guide 7 and reaches the base end surface 702 of the insulating guide 7. In the axial direction of the insulation guide 7, the second outer peripheral surface 76 is longer than the third outer peripheral surface 77. In other words, the third outer peripheral surface 77 is shorter than the second outer peripheral surface 76 in the axial direction of the insulation guide 7. In the axial direction of the insulation guide 7, the third outer peripheral surface 77 is shorter than the first outer peripheral surface 75.

The outer peripheral surface of the insulation guide 7 has an outer step portion 79. The outer step portion 79 is arranged between the second outer peripheral surface 76 and the third outer peripheral surface 77. The outer step portion 79 is a surface perpendicular to the axial direction of the insulating guide 7.

FIG. 11 is a view of the insulation guide 7 as viewed from the base end side. As shown in FIGS. 9 and 11, the insulating guide 7 has a plurality of communication passages 703. In this embodiment, the insulation guide 7 has six communication passages 703. However, the number of communication passages 703 is not limited to 6, and may be less than 6 or more than 6.

FIG. 12 shows a cross section of the insulating guide 7 including the axis of one communication passage 703. As shown in FIG. 12, the communication passage 703 communicates the outside of the insulation guide 7 with the inside of the hole 706 of the insulation guide 7. In other words, the communication passage 703 communicates the outside of the insulation guide 7 with the gas passage inside the insulation guide 7. The insulation guide 7 connects the space between the first inner peripheral surface 71 of the insulation guide 7 and the outer peripheral surface of the electrode 6 and the space outside the insulation guide 7. The communication passage 703 extends in a direction inclined with respect to the axial direction. The communication passage 703 is inclined toward the tip of the insulating guide 7 so as to approach the axis of the insulating guide 7. The inclination angle of the communication passage 703 with respect to the axial direction of the insulation guide 7 is preferably 30 degrees or more and 60 degrees or less. For example, the inclination angle of the communication passage 703 with respect to the axial direction of the insulation guide 7 is 45 degrees.

One end of the communication passage 703 is connected to the inner step portion 72. The other end of the communication passage 703 is connected to the outer step portion 79. The communication passage 703 is connected to the outer peripheral surface of the insulation guide 7 at a position closer to the base end side than the center in the axial direction of the insulation guide 7. The communication passage 703 connects the first communication passage 704 and the second communication passage 705. Have.

The first passage 704 has a larger flow path cross section than the second passage 705. The first passage 704 is connected to the outer step portion 79. The first communication passage 704 communicates with the outside of the insulation guide 7. The second passage 705 is connected to the inner step portion 72. The second communication passage 705 communicates with the gas passage in the insulation guide 7. Although only one communication passage 703 is shown in FIG. 12, the other communication passages 703 have the same structure as the communication passage 703 in FIG.

As shown in FIG. 11, the plurality of communication passages 703 are inclined with respect to the circumferential direction and the radial direction. All passages 703 are inclined in the same direction with respect to the circumferential direction. All passages 703 are inclined in the same direction with respect to the radial direction. As a result, the gas blown out from the communication passage 703 becomes a swirling flow. The plurality of communication passages 703 are arranged at equal intervals in the circumferential direction of the insulating guide 7. When viewed from the axial direction of the insulating guide 7, the axis of the communication passage 703 is parallel to the axis of the communication passage 703 and is separated from the straight line passing through the center of the insulation guide 7 by a predetermined distance.

In the insulation guide 7, at least the first inner peripheral surface 71 may have a light reflectance of 10% or more. More preferably, the first inner peripheral surface and the inner step portion 72 may have a light reflectance of 10% or more. Alternatively, in the resin guide 7, at least the first inner peripheral surface 71 may have a color having a brightness of 4 or more. Therefore, the portion of the resin guide 7 other than the first inner peripheral surface 71 may have a different color from the first inner peripheral surface 71. More preferably, it is sufficient that the first inner peripheral surface and the inner step portion 72 have a color having a brightness of 4 or more. Therefore, the portion of the resin guide 7 other than the first inner peripheral surface 71 and the inner step portion 72 may have a color different from that of the first inner peripheral surface 71. For example, the outer peripheral surface of the resin guide 7 may have a different color from the first inner peripheral surface 71. Alternatively, the second inner peripheral surface 73 of the resin guide may have a different color from the first inner peripheral surface 71.

Next, the nozzle 8 will be described. 13 and 14 are perspective views of the nozzle 8. FIG. 15 is a cross-sectional view of the nozzle 8. The nozzle 8 has a cylindrical shape with a tapered tip. The nozzle 8 has a hole 811 into which the insulating guide 7 is inserted, and is joined to the insulating guide 7 by press fitting. Specifically, the nozzle 8 has a first nozzle portion 81, a second nozzle portion 82, and a third nozzle portion 83.

The first nozzle portion 81 includes the base end of the nozzle 8. The first nozzle portion 81 has a first hole 811. The first hole 811 is connected to the base end surface 802 of the nozzle 8. The second nozzle portion 82 is located on the tip end side of the first nozzle portion 81. The second nozzle portion 82 is located between the first nozzle portion 81 and the third nozzle portion 83 in the axial direction of the nozzle 8. In the axial direction of the nozzle 8, the second nozzle portion 82 is longer than the first nozzle portion 81.

The second nozzle portion 82 has a second hole 821 that communicates with the first hole 811. The second hole 821 has an inner diameter smaller than that of the first hole 811. Therefore, an inner step portion 84 is provided between the inner peripheral surface 812 of the first nozzle portion 81 and the inner peripheral surface 822 of the second nozzle portion 82. The inner step portion 84 is a surface perpendicular to the axial direction of the nozzle 8.

The outer diameter of the second nozzle portion 82 is the same as the outer diameter of the first nozzle portion 81. Therefore, the outer peripheral surface 823 of the second nozzle portion 82 is flush with the outer peripheral surface 813 of the first nozzle portion 81. The base end of the outer peripheral surface 813 of the first nozzle portion 81 is chamfered. The second nozzle portion 82 has a larger radial thickness than the first nozzle portion 81.

The third nozzle portion 83 is located on the tip end side of the second nozzle portion 82. The third nozzle portion 83 includes the tip of the nozzle 8. The third nozzle portion 83 is located on the tip end side of the second nozzle portion 82. The third nozzle portion 83 has an injection hole 831. The injection hole 831 communicates with the second hole 821. The injection hole 831 has an inner diameter smaller than that of the second hole 821. The injection hole 831 extends in the axial direction of the nozzle 8 and reaches the tip surface 801 of the nozzle 8. In the axial direction of the nozzle 8, the first hole 811 described above is shorter than the injection hole 831.

The outer peripheral surface of the nozzle 8 has a first outer peripheral surface 85, a second outer peripheral surface 86, and a third outer peripheral surface 87. The first outer peripheral surface 85 reaches the base end surface 802 of the nozzle 8. The first outer peripheral surface 85 is composed of an outer peripheral surface 813 of the first nozzle portion 81 and an outer peripheral surface 823 of the second nozzle portion 82. The first outer peripheral surface 85 has a linear shape extending in the axial direction of the nozzle 8 in a cross-sectional view. In other words, the first outer peripheral surface 85 has a flat shape without unevenness in a cross-sectional view.

The second outer peripheral surface 86 is located on the tip end side of the first outer peripheral surface 85. The second outer peripheral surface 86 is located between the first outer peripheral surface 85 and the third outer peripheral surface 87 in the axial direction of the nozzle 8. The second outer peripheral surface 86 has an outer diameter smaller than that of the first outer peripheral surface 85. Therefore, an outer step portion 88 is provided between the first outer peripheral surface 85 and the second outer peripheral surface 86. The outer step portion 88 is a surface perpendicular to the axial direction of the nozzle 8.

The third outer peripheral surface 87 is located on the tip end side of the second outer peripheral surface 86. The third outer peripheral surface 87 reaches the tip surface 801 of the nozzle 8. The third outer peripheral surface 87 is inclined so as to be smaller in the radial direction toward the tip end.

The insulation guide 7 is inserted into the first hole 811 of the first nozzle portion 81. The electrode 6 is inserted into the second hole 821 of the second nozzle portion 82. As shown in FIG. 4, the inner peripheral surface 822 of the second nozzle portion 82 faces the electrode main body portion 61 with a gap. The inner peripheral surface 822 of the second nozzle portion 82 has a straight portion 824. The straight portion 824 extends linearly from the proximal end side to the distal end side. The inner peripheral surface of the third nozzle portion 83 has a tapered portion 825. The tapered portion 825 is located on the distal end side of the straight portion 824, and the diameter is reduced from the proximal end side to the distal end side. The tapered portion 825 is located between the straight portion 824 and the injection hole 831. The tip of the electrode 6 faces the tapered portion 825.

The first nozzle portion 81 is joined to the insulating guide 7. Specifically, the second joint portion 78 of the insulating guide 7 is inserted into the first hole 811, and the first nozzle portion 81 is joined to the second joint portion 78 of the insulating guide 7 by press fitting. As a result, the inner peripheral surface 812 of the first nozzle portion 81 is joined to the insulating guide 7 so as to seal the fluid without the O-ring.

By joining the inner peripheral surface 812 of the first nozzle portion 81 to the second joint portion 78 of the insulating guide 7, the nozzle 8 and the insulating guide 7 are positioned with each other in the radial direction. Further, when the tip surface 701 of the insulating guide 7 comes into contact with the inner step portion 84 of the nozzle 8, the nozzle 8 and the insulating guide 7 are positioned with each other in the axial direction.

The inner peripheral surface 812 of the first nozzle portion 81 has an uneven shape that is locked to the outer peripheral surface of the insulating guide 7. Specifically, the inner peripheral surface 812 of the first nozzle portion 81 has a convex portion 814. The convex portion 814 of the first nozzle portion 81 is locked to the convex portion 781 of the second joint portion 78 of the insulating guide 7. As a result, the nozzle 8 is prevented from coming off with respect to the insulating guide 7.

The second outer peripheral surface 86 has an uneven shape that locks to the inner peripheral surface of the insulating ring 9. Specifically, the second outer peripheral surface 86 has a convex portion 861.

A concave groove 89 is provided on the inner peripheral surface 822 of the second nozzle portion 82. The concave groove 89 has a shape recessed outward in the radial direction. The concave groove 89 extends in the circumferential direction and has an annular shape. The concave groove 89 is provided in the straight portion 824. The concave groove 89 is located between the tip of the electrode 6 and the tip of the insulating guide 7 in the axial direction of the nozzle 8. The concave groove 89 is located inward in the radial direction of the outer peripheral surface 823 of the second nozzle portion 82.

The straight portion 824 of the second nozzle portion 82 has a first inner peripheral surface 826 located on the tip end side of the concave groove 89 and a second inner peripheral surface 827 located on the proximal end side of the concave groove 89. .. The first inner peripheral surface 826 and the second inner peripheral surface 827 extend along the axial direction. The inner diameter of the first inner peripheral surface 826 is the same as the inner diameter of the second inner peripheral surface 827. The concave groove 89 has a step portion 891 and an inclined surface 892.

The step portion 891 extends radially outward from the second inner peripheral surface 827. The step portion 891 is a surface perpendicular to the axial direction of the nozzle 8. The inclined surface 892 connects the first inner peripheral surface 826 and the step portion 891. The inclined surface 892 is inclined with respect to the axial direction of the nozzle 8 so that the inner diameter of the inclined surface 892 expands from the tip end side to the base end side.

16 and 17 are perspective views of the insulating ring 9. FIG. 18 is a cross-sectional view of the insulating ring 9. As shown in FIGS. 16-18, the insulating ring 9 has a hole 903 into which the nozzle 8 is inserted. The inner peripheral surface 91 of the insulating ring 9 has a convex portion 911. The outer peripheral surface 92 of the insulating ring 9 has a convex portion 921.

The insulating ring 9 has a flange portion 93. The flange portion 93 projects from the outer peripheral surface 92 of the insulating ring 9. Therefore, a step portion 94 is provided between the outer peripheral surface 92 of the insulating ring 9 and the flange portion 93. The step portion 94 is a surface perpendicular to the axial direction of the insulating ring 9.

As shown in FIG. 4, the insulating ring 9 is joined to the nozzle 8 by press fitting. Specifically, the inner peripheral surface 91 of the insulating ring 9 is joined to the second outer peripheral surface 86 of the nozzle 8 by press fitting. By joining the inner peripheral surface 91 of the insulating ring 9 to the second outer peripheral surface 86 of the nozzle 8, the insulating ring 9 and the nozzle 8 are positioned with each other in the radial direction.

Further, when the base end surface 901 of the insulating ring 9 comes into contact with the outer end portion 88 of the nozzle 8, the insulating ring 9 and the nozzle 8 are positioned with each other in the axial direction. The convex portion 911 of the inner peripheral surface 91 of the insulating ring 9 is locked to the convex portion 861 of the second outer peripheral surface 86 of the nozzle 8. As a result, the insulating ring 9 is firmly prevented from coming off with respect to the nozzle 8.

19 and 20 are perspective views of the shield cap 10. FIG. 21 is a cross-sectional view of the shield cap 10. As shown in FIGS. 19 to 21, the shield cap 10 has a hole 103. The nozzle 8 is inserted into the hole 103 of the shield cap 10. The shield cap 10 has an injection hole 104. The injection hole 104 communicates with the hole 103 and penetrates the tip surface 101 of the shield cap 10 in the axial direction.

The shield cap 10 has a first inner peripheral surface 11 and a second inner peripheral surface 12. The first inner peripheral surface 11 extends in the axial direction of the shield cap 10 and reaches the base end surface 102 of the shield cap 10. The first inner peripheral surface 11 has a convex portion 111. The second inner peripheral surface 12 is located on the tip end side of the first inner peripheral surface 11. The second inner peripheral surface 12 is inclined so as to be smaller in the radial direction toward the tip end.

The shield cap 10 has a first outer peripheral surface 13, a flange portion 14, a second outer peripheral surface 15, and a third outer peripheral surface 16. The first outer peripheral surface 13 extends in the axial direction of the shield cap 10 and reaches the base end surface 102 of the shield cap 10. The flange portion 14 is located on the tip end side of the first outer peripheral surface 13. The flange portion 14 is located between the first outer peripheral surface 13 and the second outer peripheral surface 15 in the axial direction of the shield cap 10. The flange portion 14 projects from the first outer peripheral surface 13. The flange portion 14 projects from the second outer peripheral surface 15. An outer step portion 17 is provided between the flange portion 14 and the second outer peripheral surface 15. The outer step portion 17 is a surface perpendicular to the axial direction of the shield cap 10. The outer diameter of the flange portion 14 is larger than the diameter of the opening 41 of the first retainer cap 4. The outer diameter of the flange portion 14 is larger than the diameter of the opening 51 of the second retainer cap 5.

The second outer peripheral surface 15 is located on the tip end side of the flange portion 14. The second outer peripheral surface 15 has an outer diameter smaller than that of the first outer peripheral surface 13. The second outer peripheral surface 15 extends in the axial direction of the shield cap 10. The third outer peripheral surface 16 is located on the tip end side of the second outer peripheral surface 15. The third outer peripheral surface 16 reaches the tip surface 101 of the shield cap 10. The third outer peripheral surface 16 is inclined with respect to the axial direction of the shield cap 10 so as to decrease in the radial direction toward the tip end.

FIG. 22 is a cross-sectional view taken along the line AA of FIG. As shown in FIGS. 21 and 22, the shield cap 10 has a plurality of communication passages 105. The communication passage 105 communicates the outside of the shield cap 10 with the inside of the hole 103 of the shield cap 10. One end of the communication passage 105 reaches the first outer peripheral surface 13. The other end of the communication passage 105 reaches the first inner peripheral surface 11.

The communication passages 105 are arranged at equal intervals in the circumferential direction of the shield cap 10. When viewed from the axial direction of the shield cap 10, the axis of the communication passage 105 is parallel to the axis of the communication passage 105 and is separated from the straight line passing through the center of the insulation guide 7 by a predetermined distance. All the passages 105 are inclined in the same direction with respect to the circumferential direction. All passages 105 are inclined in the same direction with respect to the radial direction. As a result, the gas blown out from the communication passage 105 becomes a swirling flow.

As shown in FIG. 4, the shield cap 10 is joined to the insulating ring 9 by press fitting. Specifically, the first inner peripheral surface 11 of the shield cap 10 is joined to the outer peripheral surface 92 of the insulating ring 9 by press fitting. The convex portion 111 of the first inner peripheral surface 11 of the shield cap 10 engages with the convex portion 921 of the outer peripheral surface 92 of the insulating ring 9. As a result, the shield cap 10 is firmly prevented from coming off from the insulating ring 9.

By joining the first inner peripheral surface 11 of the shield cap 10 to the outer peripheral surface 92 of the insulating ring 9, the shield cap 10 and the insulating ring 9 are positioned with each other in the radial direction. As a result, the injection holes 104 of the shield cap 10 and the injection holes 831 of the nozzle 8 are arranged concentrically.

When the base end surface 102 of the shield cap 10 comes into contact with the stepped portion 94 of the insulating ring 9, the shield cap 10 and the insulating ring 9 are positioned with each other in the axial direction. As a result, the shield cap 10 is arranged with respect to the nozzle 8 with a gap. Specifically, the second inner peripheral surface 12 of the shield cap 10 is arranged with a gap from the third outer peripheral surface 87 of the nozzle 8. As a result, a gas passage described later is formed between the shield cap 10 and the nozzle 8. The communication passage 105 of the shield cap 10 is located on the tip side of the tip of the insulating ring 9. The communication passage 105 of the shield cap 10 communicates with the gas passage between the shield cap 10 and the nozzle 8.

Next, the center pipe 20 will be described. 23 and 24 are perspective views of the center pipe 20. FIG. 25 is a cross-sectional view of the center pipe 20. The center pipe 20 is inserted into the internal passage 65 of the electrode 6 and supplies cooling water into the electrode 6. The center pipe 20 is made of a conductor. The center pipe 20 has a pipe body 21 and a contactor 22. FIG. 26 is a perspective view of the pipe body 21. FIG. 27 is a perspective view of the contactor 22.

The pipe body 21 has a tubular shape. The pipe body 21 is made of a conductor. Specifically, the outer peripheral surface of the pipe body 21 has a flange portion 23, a first outer peripheral surface 24, a second outer peripheral surface 25, and a third outer peripheral surface 26. The flange portion 23 includes the base end of the pipe body 21. The flange portion 23 projects from the first outer peripheral surface 24. Therefore, a step portion 27 is provided between the flange portion 23 and the first outer peripheral surface 24. The step portion 27 is a surface perpendicular to the axial direction of the pipe body 21.

The first outer peripheral surface 24 is located on the tip end side of the flange portion 23. The first outer peripheral surface 24 is located between the flange portion 23 and the second outer peripheral surface 25 in the axial direction of the pipe body 21. The first outer peripheral surface 24 extends in the axial direction of the pipe body 21.

The second outer peripheral surface 25 is located on the tip end side of the first outer peripheral surface 24. The second outer peripheral surface 25 is located between the first outer peripheral surface 24 and the third outer peripheral surface 26 in the axial direction of the pipe body 21. The second outer peripheral surface 25 extends in the axial direction of the pipe body 21. In the axial direction of the pipe body 21, the second outer peripheral surface 25 is shorter than the first outer peripheral surface 24. The second outer peripheral surface 25 has an outer diameter smaller than that of the first outer peripheral surface 24.

The third outer peripheral surface 26 is located on the tip end side of the second outer peripheral surface 25. The third outer peripheral surface 26 includes the tip of the pipe body 21. The third outer peripheral surface 26 extends in the axial direction of the pipe body 21. The third outer peripheral surface 26 is longer than the first outer peripheral surface 24 in the axial direction of the pipe body 21. The third outer peripheral surface 26 has an outer diameter smaller than that of the second outer peripheral surface 25. A recess 261 is provided in the middle portion of the third outer peripheral surface 26 in the axial direction. A contactor 22 is attached to the recess 261.

The pipe body 21 has a cooling water passage inside. The cooling water passage penetrates the pipe body 21 in the axial direction. The cooling water passage has a first passage 211, a second passage 212, and a third passage 231. The first passage 211 reaches the base end surface 201 of the pipe body 21. The first passage 211 is inclined with respect to the axial direction of the pipe body 21 so as to decrease in the radial direction toward the tip.

The second passage 212 is located on the tip end side of the first passage 211. The second passage 212 is located between the first passage 211 and the third passage 231 in the axial direction of the pipe body 21. In the axial direction of the pipe body 21, the second passage 212 is longer than the third passage 231. The second passage 212 extends in the axial direction of the pipe body 21.

The third passage 231 is located on the tip end side of the second passage 212. The third passage 231 reaches the tip surface 202 of the pipe body 21. The third passage 231 has a larger inner diameter than the second passage 212. The convex portion 67 of the electrode 6 described above is arranged in the third passage 231.

The contactor 22 is separate from the pipe body 21. The contactor 22 is made of a conductor. The contactor 22 is detachably attached to the pipe body 21. The contactor 22 is attached to the outer peripheral surface of the pipe body 21. Specifically, the contactor 22 is attached to the pipe body 21 by being fitted into the recess 261 of the third outer peripheral surface 26 of the pipe body 21.

The contactor 22 has a mounting portion 28 and a contact portion 29. The mounting portion 28 is mounted on the outer peripheral surface of the pipe body 21. The mounting portion 28 has a first ring portion 281 and a second ring portion 282. The second ring portion 282 is arranged away from the first ring portion 281 in the axial direction of the contact 22. The first ring portion 281 and the second ring portion 282 are fitted into the recesses 261 of the pipe body 21, respectively.

The contact portion 29 contacts the inner peripheral surface of the electrode 6. The contact portion 29 has elasticity so as to generate a reaction force when pressed in the radial direction of the contactor 22. Specifically, the contact portion 29 has a plurality of curved portions 291. The curved portion 291 connects the first ring portion 281 and the second ring portion 282. The curved portion 291 has a plate-like shape that bulges outward in the radial direction of the contact 22. The contact portion 29 has a plurality of slits 292. The slit 292 is provided between the plurality of curved portions 291 and extends in the axial direction of the contactor 22. In the drawings, reference numeral 292 is attached only to a part of the slit 292, and the reference numerals of the other slits 292 are omitted.

FIG. 28 is a view of the contactor 22 as viewed from the axial direction. As shown in FIG. 28, the plurality of curved portions 291 are arranged at equal intervals in the circumferential direction of the contactor 22. Similarly, the plurality of slits 292 are also arranged at equal intervals in the circumferential direction of the contactor 22. In this embodiment, the contactor 22 has eight curved portions 291 and eight slits 292. However, the number of contacts 22 is not limited to eight and may be less than eight or more than eight. Similarly, the number of slits 292 is not limited to eight, and may be less than eight or more than eight.

As shown in FIG. 1, the flange portion 23 of the center pipe 20 is arranged between the base end surface 341 of the electrode pedestal 34 and the bottom surface 331 of the hole of the base portion 33. The flange portion 23 is in contact with the base end surface 341 of the electrode pedestal 34. As a result, the center pipe 20 and the electrode pedestal 34 are electrically connected. Further, the center pipe 20 is positioned in the radial direction and the axial direction.

FIG. 29 is an enlarged view of the configuration of the replacement part unit 2a and its surroundings in FIG. As shown in FIG. 29, the contactor 22 of the center pipe 20 is in contact with the inner peripheral surface of the electrode 6. The contactor 22 is elastically deformed inward in the radial direction by being inserted into the internal passage 65 of the electrode 6. The contactor 22 is pressed against the inner peripheral surface of the electrode 6 by the reaction force of elastic deformation. The center pipe 20 is electrically connected to the electrode pedestal 34. Therefore, the contactor 22 energizes the electrode 6 by contacting the inner peripheral surface of the electrode 6.

The electrode 6 has a first energizing surface 603 and a second energizing surface 601. The first energizing surface 603 is a portion of the inner peripheral surface of the internal passage 65 that is in contact with the contactor 22. The electrode 6 is electrically connected to the electrode pedestal 34 via the center pipe 20 and the first energizing surface 603. The first energizing surface 603 is arranged adjacent to the tapered portion 652 on the tip end side of the tapered portion 652. The first energizing surface 603 is located in the cooling water passage described later.

The second energizing surface 601 is the base end surface 601 of the electrode 6. The second energizing surface 601 is in contact with the tip surface 342 of the electrode pedestal 34. The electrode 6 is electrically connected to the electrode pedestal 34 via the second energizing surface 601. The second energizing surface 601 is adjacent to the cooling water passage described later.

1.3 Cooling water passage Next, the cooling water passage of the plasma torch 1a will be described. In FIG. 1, solid arrows indicate the flow of cooling water. As shown in FIG. 1, a cooling water supply pipe 45 is connected to the base portion 33. The cooling water supply pipe 45 is connected to the second cooling water passage W2 in the nozzle pedestal 36 via the first cooling water passage W1 in the base portion 33. The first cooling water passage W1 extends from the base end surface of the base portion 33 toward the outer peripheral surface of the base portion 33. The second cooling water passage W2 extends from the inner peripheral surface of the nozzle pedestal 36 toward the tip of the nozzle pedestal 36. The second cooling water passage W2 is connected to the third cooling water passage W3. The third cooling water passage W3 is an annular passage surrounded by the nozzle pedestal 36, the first retainer cap 4, and the replacement part unit 2a.

As shown in FIG. 29, a gap is provided between the tip surface 371 of the insulating sleeve 37 and the base end surface 802 of the nozzle 8, and this gap constitutes a part of the third cooling water passage W3. There is. Therefore, the base end surface 802 of the nozzle 8 is arranged in the third cooling water passage W3. Further, the gap between the tip surface 371 of the insulating sleeve 37 and the base end surface 802 of the nozzle 8 reaches the second outer peripheral surface 76 of the insulating guide 7. Therefore, a part of the second outer peripheral surface 76 of the insulation guide 7 is arranged in the third cooling water passage W3.

As shown in FIG. 1, the third cooling water passage W3 is included in the fourth cooling water passage W4 in the nozzle pedestal 36, the fifth cooling water passage W5 between the nozzle pedestal 36 and the insulating sleeve 37, and the insulating sleeve 37. It is connected to the eighth cooling water passage W8 via the sixth cooling water passage W6 and the seventh cooling water passage W7 in the electrode pedestal 34.

The fourth cooling water passage W4 extends from the tip of the nozzle pedestal 36 toward the inner peripheral surface of the nozzle pedestal 36. The fifth cooling water passage W5 is an annular passage provided between the nozzle pedestal 36 and the insulating sleeve 37. The sixth cooling water passage W6 is a plurality of passages extending in the radial direction from the outer peripheral surface of the insulating sleeve 37 toward the inner peripheral surface of the insulating sleeve 37. The seventh cooling water passage W7 is a plurality of passages extending in the radial direction from the outer peripheral surface of the electrode pedestal 34 toward the inner peripheral surface of the electrode pedestal 34. The eighth cooling water passage W8 is a passage between the electrode pedestal 34 and the center pipe 20.

The eighth cooling water passage W8 is connected to the ninth cooling water passage W9 between the electrode 6 and the center pipe 20. The ninth cooling water passage W9 communicates with the tenth cooling water passage W10 in the center pipe 20 at the tip end portion of the center pipe 20. The tenth cooling water passage W10 is connected to the cooling water discharge pipe 46 via the eleventh cooling water passage W11 in the base portion 33.

The cooling water flows from the cooling water supply source through the cooling water supply pipe 45, the first cooling water passage W1 in the base 33, the second cooling water passage W2 in the nozzle pedestal 36, and the third cooling water passage W3. Is supplied to. The cooling water is from the third cooling water passage W3 to the fourth cooling water passage W4 in the nozzle pedestal 36, the fifth cooling water passage W5 between the nozzle pedestal 36 and the insulating sleeve 37, and the sixth cooling water in the insulating sleeve 37. It is supplied to the eighth cooling water passage W8 between the electrode pedestal 34 and the center pipe 20 through the passage W6 and the seventh cooling water passage W7 in the electrode pedestal 34. The cooling water is from the eighth cooling water passage W8, the ninth cooling water passage W9 between the electrode 6 and the center pipe 20, the tenth cooling water passage W10 in the center pipe 20, and the eleventh cooling water in the base portion 33. It is discharged to the outside of the plasma torch 1a through the passage W11 and the cooling water discharge pipe 46.

1.4 Gas passage Next, the plasma gas passage of the plasma torch 1a will be described. In this embodiment, the plasma gas is oxygen gas. That is, in the present embodiment, the plasma torch 1a is a plasma torch for cutting oxygen plasma. However, a plasma gas other than oxygen gas may be used. FIG. 30 is a cross-sectional view different from FIG. 1 along the central axis of the plasma torch 1a. In FIGS. 1 and 30, the dashed arrow indicates the flow of plasma gas. Specifically, the dashed arrow in FIG. 30 indicates the flow of the main gas. In FIG. 1, the broken line arrow indicates the flow of the assist gas.

As shown in FIG. 30, a main gas supply pipe 47 is connected to the base portion 33. The main gas supply pipe 47 is connected to the second main gas passage MG2 between the base portion 33 and the insulating sleeve 37 via the first main gas passage MG1 in the base portion 33. The first main gas passage MG1 extends in the axial direction from the base end surface of the base portion 33 toward the step portion 332 of the inner peripheral surface of the base portion 33. The second main gas passage MG2 is an annular passage formed between the step portion 332 on the inner peripheral surface of the base portion 33 and the step portion 372 on the outer peripheral surface of the insulating sleeve 37.

The second main gas passage MG2 is connected to the fourth main gas passage MG4 via the third main gas passage MG3 in the insulating sleeve 37. The third main gas passage MG3 extends in the axial direction from the step portion 372 on the outer peripheral surface of the insulating sleeve 37. The fourth main gas passage MG4 is an annular passage between the insulating sleeve 37 and the replacement part unit 2a.

FIG. 31 is an enlarged view of the configuration of the replacement part unit 2a and its surroundings in FIG. 30. As shown in FIG. 31, the fourth main gas passage MG4 is composed of an inner peripheral surface of the insulating sleeve 37, an outer peripheral surface of the insulating guide 7, and an outer peripheral surface of the electrode 6.

Specifically, a step portion 373 is provided on the inner peripheral surface of the insulating sleeve 37. The step portion 373 is a surface perpendicular to the axial direction of the insulating sleeve 37. With the replacement component unit 2a attached to the torch body 3, the outer step portion 79 of the insulation guide 7 is arranged with a gap from the step portion 373 on the inner peripheral surface of the insulation sleeve 37. The fourth main gas passage MG4 passes through a gap between the outer step portion 79 of the insulating guide 7 and the step portion 373 on the inner peripheral surface of the insulating sleeve 37.

The fourth main gas passage MG4 is sealed by an O-ring R2 with respect to the above-mentioned third cooling water passage W3. The O-ring R2 is fitted in a recess 374 provided on the inner peripheral surface of the insulating sleeve 37. The O-ring R2 is in contact with a part of the second outer peripheral surface 76 of the insulating guide 7. That is, the second outer peripheral surface 76 of the insulating guide 7 has a sealing surface 761 that comes into contact with the O-ring. A portion of the second outer peripheral surface 76 on the tip side of the seal surface 761 is arranged in the third cooling water passage W3. A portion of the second outer peripheral surface 76 on the base end side of the seal surface 761 is arranged in the fourth main gas passage MG4. The third outer peripheral surface 77 is also arranged in the fourth main gas passage MG4 in the same manner as the second outer peripheral surface 76.

As shown in FIG. 29, the fourth main gas passage MG4 is sealed by the O-ring R3 with respect to the above-mentioned sixth cooling water passage W6 and the seventh cooling water passage W7. The O-ring R3 is fitted in a recess 375 provided on the inner peripheral surface of the insulating sleeve 37. The O-ring R3 is in contact with a part of the outer peripheral surface of the flange portion 63 of the electrode 6. That is, the outer peripheral surface of the flange portion 63 has a sealing surface 631 that comes into contact with the O-ring R3. A portion of the outer peripheral surface of the flange portion 63 on the tip side of the seal surface 631 is arranged in the fourth main gas passage MG4.

As shown in FIG. 31, the fourth main gas passage MG4 is connected to the fifth main gas passage MG5 between the insulation guide 7 and the electrode 6 via a plurality of communication passages 703 of the insulation guide 7. The fifth main gas passage MG5 is an annular passage between the inner peripheral surface of the insulating guide 7 and the outer peripheral surface of the electrode 6. The fifth main gas passage MG5 is connected to the sixth main gas passage MG6 between the nozzle 8 and the electrode 6. The inner diameter of the fifth main gas passage MG5 is the same as the inner diameter of the sixth main gas passage MG6. The sixth main gas passage MG6 communicates with the injection hole 831 of the nozzle 8.

The main gas is the first main gas passage MG1 in the base portion 33, the second main gas passage MG2 between the base portion 33 and the insulating sleeve 37, and the third main gas in the insulating sleeve 37 from the main gas supply source. It flows through the passage MG3 to the fourth main gas passage MG4 between the insulating sleeve 37 and the replacement part unit 2a. The main gas becomes a swirling flow from the fourth main gas passage MG4 through the communication passage 703, and is ejected to the fifth main gas passage MG5. The swirling main gas is ejected from the injection hole 831 of the nozzle 8 through the sixth main gas passage MG6.

As shown in FIG. 1, an assist gas supply pipe 48 is connected to the base portion 33. The assist gas supply pipe 48 is connected to the second assist gas passage AG2 in the nozzle pedestal 36 via the first assist gas passage AG1 in the base portion 33. The first assist gas passage AG1 extends from the base end surface of the base portion 33 toward the outer peripheral surface of the base portion 33. The second assist gas passage AG2 extends from the inner peripheral surface of the nozzle pedestal 36 toward the outer peripheral surface of the nozzle pedestal 36.

The second assist gas passage AG2 is connected to the fourth assist gas passage AG4 between the holder 38 and the second retainer cap 5 via the third assist gas passage AG3 in the holder 38. The third assist gas passage AG3 extends from the inner peripheral surface of the holder 38 toward the outer peripheral surface. The fourth assist gas passage AG4 is an annular passage between the outer peripheral surface of the holder 38 and the inner peripheral surface of the second retainer cap 5.

The fourth assist gas passage AG4 is connected to the sixth assist gas passage AG6 between the first retainer cap 4 and the second retainer cap 5 via the fifth assist gas passage AG5 in the second retainer cap 5. .. The fifth assist gas passage AG5 is a plurality of passages extending from the inner peripheral surface of the second retainer cap 5 toward the outer peripheral surface. The sixth assist gas passage AG6 is an annular passage between the inner peripheral surface of the first retainer cap 4 and the outer peripheral surface of the second retainer cap 5.

As shown in FIG. 29, the sixth assist gas passage AG6 is connected to the seventh assist gas passage AG7 between the nozzle 8 and the shield cap 10 via a plurality of communication passages 105 of the shield cap 10. The seventh assist gas passage AG7 communicates with the injection hole 831 of the nozzle 8 and the injection hole 104 of the shield cap 10.

The sixth assist gas passage AG6 is sealed by an O-ring R4 with respect to the above-mentioned third cooling water passage W3. The O-ring R4 is fitted in a recess 44 provided at the tip of the inner peripheral surface of the first retainer cap 4. The O-ring R4 is in contact with the first outer peripheral surface 13 of the shield cap 10. That is, the first outer peripheral surface 13 of the shield cap 10 has a seal surface 131 that comes into contact with the O-ring R4.

As described above, the insulating ring 9 is joined to the nozzle 8 by press fitting. Further, the insulating ring 9 is joined to the shield cap 10 by press fitting. Therefore, the seventh assist gas passage AG7 is sealed by the insulating ring 9 with respect to the above-mentioned third cooling water passage W3.

From the assist gas supply source, the assist gas is the first assist gas passage AG1 in the base portion 33, the second assist gas passage AG2 in the nozzle pedestal 36, the third assist gas passage AG3 in the holder 38, the holder 38 and the first. The sixth assist between the first retainer cap 4 and the second retainer cap 5 through the fourth assist gas passage AG4 between the two retainer caps 5 and the fifth assist gas passage AG5 in the second retainer cap 5. It flows into the gas passage AG6. The assist gas becomes a swirling flow from the 6th assist gas passage AG6 through the communication passage 105, and is ejected into the 7th assist gas passage AG7. The swirling assist gas is ejected from the injection hole 104 of the shield cap 10 together with the main gas through the seventh assist gas passage AG7.

1.5 Replacement method of replacement component unit Next, a replacement method of the replacement component unit 2a will be described. The replacement part unit 2a is a consumable item. Therefore, the replacement part unit 2a is detachably attached to the torch body 3, and when it is consumed to the extent that it needs to be replaced, it is replaced with a new one. As shown in FIG. 29, in the plasma torch 1a, the step portion 17 of the shield cap 10 is pressed in the axial direction by the edge portion of the opening 51 of the second retainer cap 5. Further, the flange portion 14 of the shield cap 10 is sandwiched between the edge portion of the opening 41 of the first retainer cap 4 and the edge portion of the opening 51 of the second retainer cap 5. As a result, the replacement part unit 2a is fixed. Therefore, when replacing the replacement component unit 2a, the second retainer cap 5 is first removed.

When the second retainer cap 5 is removed, the replacement part unit 2a is held by the elastic force of the O-rings R2, R3, and R4. Therefore, by pulling out the replacement part unit 2a from the opening 41 of the first retainer cap 4 toward the tip side, the insulating guide 7 and the electrode 6 of the replacement part unit 2a are pulled out from the insulating sleeve 37. At that time, the contactor 22 of the center pipe 20 slides along the inner peripheral surface of the electrode 6, and the electrode 6 is pulled out from the center pipe 20.

Before pulling out the replacement part unit 2a from the opening 41 of the first retainer cap 4 toward the tip side, it is preferable to loosen the first retainer cap 4. As a result, the flange portion 14 of the shield cap 10 is caught by the edge portion of the opening 41 of the first retainer cap 4 and pushed out. As a result, the replacement part unit 2a can be easily removed.

As described above, the replacement part unit 2a can be easily and integrally removed from the torch main body 3.

When installing a new replacement part unit 2a, the replacement part unit 2a is inserted from the opening 41 of the first retainer cap 4 toward the base end side. As a result, the electrode 6 of the replacement component unit 2a and the insulating guide 7 are inserted into the insulating sleeve 37. At that time, the center pipe 20 is inserted into the electrode 6, and the contactor 22 of the center pipe 20 slides along the inner peripheral surface of the electrode 6.

Then, when the second retainer cap 5 is attached to the first retainer cap 4, the edge portion of the opening 51 of the second retainer cap 5 presses the step portion 17 of the shield cap 10 toward the proximal end side. As a result, the replacement component unit 2a is pushed toward the proximal end side until the proximal end surface 601 of the electrode 6 comes into contact with the distal end surface 342 of the electrode pedestal 34. Then, the flange portion 14 of the shield cap 10 is sandwiched and held by the edge portion of the opening 41 of the first retainer cap 4 and the edge portion of the opening 51 of the second retainer cap 5, so that the replacement part unit 2a is held. , Fixed.

In the insulation guide 7 according to the present embodiment described above, at least the first inner peripheral surface 71 and the inner step portion 72 have a light reflectance of 10% or more. In the plasma torch 1a, intense light is emitted from the plasma arc. The radiation from the plasma arc is gradually absorbed while being reflected by the nozzle and the electrode, but a part of the radiation reaches the insulating guide 7 while being reflected between the nozzle 8 and the electrode 6. If the first inner peripheral surface 71 of the insulating guide 7 is a color having a low reflectance such as black, the heat input due to radiation becomes large. Therefore, the insulation guide 7 may suddenly burn out.

However, in the insulation guide 7 according to the present embodiment, the first inner peripheral surface 71 and the inner step portion 72 have higher reflectance than black. Therefore, the heat input to the insulating guide 7 due to radiation can be suppressed to a low level, so that sudden burning of the insulating guide 7 can be suppressed.

2. Second Embodiment Next, the plasma torch 1b according to the second embodiment will be described. FIG. 32 is a cross-sectional view taken along the central axis of the plasma torch 1b according to the second embodiment. FIG. 33 is a cross-sectional view of the replacement component unit 2b according to the second embodiment. 34 and 35 are perspective views of the replacement part unit 2b. 36 and 37 are perspective views of the nozzle 8 according to the second embodiment.

As shown in FIG. 33, the first outer peripheral surface 85 of the nozzle 8 has a recess 851. The recess 851 is provided in the second nozzle portion 82. The recess 851 is recessed inward in the radial direction of the nozzle 8 and extends in the circumferential direction of the nozzle 8. In the axial direction of the nozzle 8, the recess 851 is arranged at substantially the same position as the tip of the electrode 6. The outer diameter of the bottom of the recess 851 is smaller than the inner diameter of the inner peripheral surface 812 of the nozzle 8.

The recess 851 has a first wall surface 852 on the proximal end side and a second wall surface 853 on the distal end side. The first wall surface 852 is inclined with respect to the radial direction of the nozzle 8. The second wall surface 853 extends in the radial direction of the nozzle 8. As shown in FIG. 32, the first wall surface 852 extends parallel to the inclined inner peripheral surface of the first retainer cap 4. The recess 851 is arranged in the third cooling water passage W3. As shown in FIG. 33, the concave groove 89 is located inward in the radial direction of the first wall surface 852.

In the present embodiment, the first retainer cap 4 is provided with a plurality of holes 43 communicating with the third cooling water passage W3. The hole 43 of the first retainer cap 4 communicates with the annular cooling water passage W12 between the first retainer cap 4 and the second retainer cap 5. In the axial direction of the nozzle 8, the recess 851 is arranged at substantially the same position as the hole 43 of the first retainer cap 4.

Other configurations of the replacement part unit 2b and the plasma torch 1b are the same as those of the replacement part unit 2a and the plasma torch 1a of the first embodiment.

In the second embodiment described above, since the recess 851 is provided in the nozzle 8, the surface area of the nozzle 8 in contact with the cooling water can be increased. Therefore, the cooling property of the nozzle 8 can be improved. Further, since the recess 851 is arranged at substantially the same position as the hole 43 of the first retainer cap 4, the cooling property of the nozzle 8 can be further improved. Further, in the cooling water passage W12, the second retainer cap 5 can also be water-cooled. Therefore, the replacement component unit 2b according to the present embodiment is suitable for plasma cutting using a large current.

3. 3. Other Embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the invention.

The structure of the replacement parts units 2a and 2b may be changed. The structures of the torch body 3, the first retainer cap 4, and the second retainer cap 5 may be modified. The structure of the electrode 6, the insulating guide 7, and the nozzle 8 may be changed.

The electrode 6, the insulating guide 7, and the nozzle 8 may be detachably joined to each other. The electrode 6 and the insulating guide 7 may be joined by adhesion instead of press fitting. The insulation guide 7 and the nozzle 8 may be joined by adhesion instead of press fitting. The nozzle 8 and the insulating ring 9 may be joined by adhesion instead of press fitting. The insulating ring 9 and the shield cap 10 may be joined by adhesion instead of press fitting.

The electrode 6 and the insulating guide 7 do not have to be attached to the nozzle 8. The electrode 6 does not have to be attached to the insulating guide 7. For example, the electrode 6 and the nozzle 8 may be attached to the torch body, and the insulating guide 7 may be sandwiched between the electrode 6 and the nozzle 8 in the axial direction.

The insulating ring 9 and the shield cap 10 do not have to be included in the replacement component units 2a and 2b. That is, the replacement component unit may be composed of the electrode 6, the insulating guide 7, and the nozzle 8. Further, the insulating ring 9 and the shield cap 10 may be easily attached to and detached from the replacement component unit.

The inner diameter of the gas passage in the insulation guide 7 may be larger than the inner diameter of the nozzle 8. That is, as shown in FIG. 38, the inner diameter of the fifth main gas passage MG5 in the insulating guide 7 may be larger than the inner diameter of the sixth main gas passage MG6 in the nozzle 8.

The recess 89 may be omitted. Alternatively, the shape and position of the groove 89 may be changed. For example, FIG. 39 is a cross-sectional view of the nozzle 8 according to the first modification. As shown in FIG. 39, in the first modification, the concave groove 89 has a second step portion 893 instead of the inclined surface 892 of the above embodiment. The second step portion 893 is located on the tip end side of the step portion 891. The second step portion 893 is a surface perpendicular to the axial direction of the nozzle 8, and extends outward in the radial direction in parallel with the step portion 891.

Alternatively, instead of the concave groove 89, a convex portion as shown in FIG. 40 may be provided. FIG. 40 is a cross-sectional view of the nozzle 8 according to the second modification. The nozzle 8 according to the second modification is provided with an annular convex portion 89 that protrudes inward in the radial direction and extends in the circumferential direction. The convex portion 89 has a first step portion 894 extending inward in the radial direction from the first inner peripheral surface 826. Further, the convex portion 89 has a second step portion 895. The second step portion 895 is located on the base end side of the step portion 894, and protrudes inward in the radial direction from the second inner peripheral surface 827. In this case, a part of the heat-resistant insert 64 can be collected at the first step portion 894 of the convex portion 89. As a result, sudden burning of the resin insulating guide 7 can be suppressed. The second step portion 896 may be provided flush with the inner step portion 84.

According to the present invention, in a plasma torch for plasma cutting, it is possible to suppress sudden burning of a resin insulating guide.

6 Electrode 7 Insulation guide 8 Nozzle 71 1st inner peripheral surface 73 2nd inner peripheral surface 703 Continuous passage

Claims (5)

Used in a plasma torch for plasma cutting having an electrode and a nozzle into which the electrode is inserted, a first inner peripheral surface and a second inner peripheral surface having an inner diameter smaller than that of the first inner peripheral surface. It is a method of manufacturing an insulating guide for connecting the electrode and the nozzle by providing a communication passage connecting the inner space of the first inner peripheral surface and the outside.
The process of melting the resin and
The process of injecting the molten resin into the mold and
The process of solidifying the resin in the mold to obtain the insulation guide, and
With
The first inner peripheral surface has a reflectance of 10% or more.
Manufacturing method of insulation guide for plasma torch. The insulating guide is made of a resin having a reflectance of 10% or more.
The method for manufacturing an insulating guide for a plasma torch according to claim 1. The insulating guide is made of a non-colored polyphenylene sulfide resin.
The method for manufacturing an insulating guide for a plasma torch according to claim 1 or 2. The insulating guide is made of a color-colored resin having a reflectance of 10% or more.
The method for manufacturing an insulating guide for a plasma torch according to any one of claims 1 to 3. The first outer peripheral surface and
A second outer peripheral surface located on the base end side of the first outer peripheral surface and having an outer diameter smaller than that of the first outer peripheral surface.
A third outer peripheral surface located on the base end side of the second outer peripheral surface and having an outer diameter smaller than that of the second outer peripheral surface.
With more
The second inner peripheral surface has a first joining portion for joining to the electrode.
The first outer peripheral surface has a second joint portion for joining to the nozzle.
The method for manufacturing an insulating guide for a plasma torch according to any one of claims 1 to 4.

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