JP6612626B2 - Plasma welding torch - Google Patents

Description

  The present invention relates to a plasma welding torch for performing plasma welding.

  In plasma welding, an electrode formed of tungsten is generally discharged as a cathode, and a main plasma arc generated at that time is constrained by a water-cooled plasma nozzle and a gas flow of plasma gas. As a result, a high-concentration high-temperature plasma flow is generated, and welding is performed using the retained energy (see, for example, Patent Document 1).

  Recently, the plasma welding has been increased in current. When the plasma welding is performed at a high current, the amount of heat of the plasma welding torch during welding increases and the temperature rises. Therefore, it is necessary to increase the flow rate of the supplied cooling water and shield gas. This is generally an obstacle to downsizing. On the other hand, in plasma welding performed on a workpiece, depending on the shape of the workpiece, the tip of the plasma welding torch may interfere with the workpiece, or the plasma welding torch may be applied to a narrow portion of the workpiece. Inconveniences such as being unable to bring the tip part close may occur. For such inconvenience, it is required to reduce the size of the tip of the plasma welding torch.

Japanese Patent No. 4707108

  The present invention has been conceived under such circumstances, and its main object is to provide a plasma welding torch suitable for reducing the size of the tip.

  In order to solve the above problems, the present invention employs the following technical means.

  A plasma welding torch provided by the present invention is provided around a torch body, an electrode provided at an axial center of the torch body, and a tip side of the electrode, and plasma gas is supplied to the inside thereof. A plasma nozzle, a shield gas cup provided around the plasma nozzle via a nozzle holder at a tip of the torch body, a cooling water flow path provided in the torch body and the plasma nozzle, and the cooling A shield gas channel provided inside the torch body and the nozzle holder outside the water channel, wherein the shield gas channel separates a plurality of shield gases in a circumferential direction around the axis of the electrode Has a branch.

  In a preferred embodiment, the plurality of shield gas branch paths are constituted by a plurality of grooves formed by being separated in the circumferential direction on the outer peripheral wall or the inner peripheral wall of the metal cylindrical member constituting the torch body. The

  In a preferred embodiment, the plurality of shield gas branch paths are evenly arranged radially in the circumferential direction of the metal cylindrical member.

  In a preferred embodiment, the cooling water flow path is formed on the inner peripheral wall of the metal cylindrical member in which the plurality of shield gas branch paths are formed on the outer peripheral wall.

  In a preferred embodiment, an insulating cylindrical member into which the electrode is inserted and a plasma gas channel provided in the insulating cylindrical member are provided, and the plasma gas channel includes the insulating cylinder. A plurality of plasma gas branch paths constituted by grooves formed separately in the circumferential direction on the inner peripheral wall of the cylindrical member.

  In a preferred embodiment, the cooling water flow path and the shield gas flow path are such that the portion near the tip of the torch body is closer to the axis of the electrode than the portion near the base end of the torch body. is there.

  According to the present invention, the shield gas flow path has a plurality of shield gas branch paths that are separated in the circumferential direction around the axis of the electrode. According to such a configuration, unlike the case where, for example, an annular flow path is provided, the gap portion can be reduced in the member for forming the shield gas flow path. As a result, it is possible to improve the strength of the member forming the shield gas flow channel as compared with the case where the annular and axially extending flow channel is provided. In addition, according to the configuration having a plurality of shield gas branch paths, the radial dimension can be reduced while ensuring a predetermined strength in the member forming the shield gas flow path, compared to the case where the annular flow path is provided. Is possible. Such a configuration is suitable for reducing the size of the tip of the plasma welding torch.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is an external view which shows an example of the plasma welding torch which concerns on this invention. It is sectional drawing which follows the II-II line | wire of FIG. It is sectional drawing which follows the III-III line of FIG. FIG. 3 is a partially enlarged view of FIG. 2. FIG. 4 is a partially enlarged view of FIG. 3. FIG. 3 is a cross-sectional view of FIG. 2. FIG. 4 is a cross-sectional view of FIG. 3.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 7 show an example of a plasma welding torch according to the present invention. FIG. 1 is an external view of a plasma welding torch 1 of the present embodiment. 2 is a cross-sectional view taken along line II-II in FIG. 1, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. 4 is a partially enlarged view of FIG. 2, and FIG. 5 is a partially enlarged view of FIG. 6A is a cross-sectional view taken along the line VIa-VIa in FIG. 2, FIG. 6B is a cross-sectional view taken along the line VIb-VIb in FIG. 2, and FIG. 2 is a cross-sectional view taken along line VIc-VIc, and FIG. 6D is a cross-sectional view taken along line VId-VId in FIG. 7A is a cross-sectional view taken along line VIIa-VIIa in FIG. 3, and FIG. 7B is a cross-sectional view taken along line VIIb-VIIb in FIG.

  As shown in FIGS. 1 to 5, the plasma welding torch 1 of this embodiment includes a torch body 2, an electrode 3, a collet 4, a collet body 5, an insulating bush 6, a cap 7, a plasma nozzle 8, a centering stone 9, and a nozzle. A holder 10 and a shield gas cup 11 are provided.

  The electrode 3 is usually made of tungsten and is provided at the axial center of the torch body 2. The electrode 3 is inserted into the collet 4, and the collet 4 is inserted into the collet body 5. The collet body 5 is attached to the torch body 2 via an insulating bush 6. The torch body 2 has a body fitting 21, a pilot fitting 22, and a plastic cover 23. The position of the electrode 3 is fixed with respect to the collet body 5 by screwing the cap 7.

  The plasma nozzle 8 is cylindrical and conductive, and the base end of the plasma nozzle 8 is attached to the tip of the torch body 2 (pilot fitting 22). A plasma ejection hole 8 a is formed at the tip of the plasma nozzle 8. The electrode 3 is inserted into the centering stone 9 so that the tip of the electrode 3 protrudes from the tip of the centering stone 9 into the plasma nozzle 8. The centering stone 9 is inserted into the plasma nozzle 8. The centering stone 9 has a function of preventing the axial displacement of the electrode 3. Further, since the centering stone 9 is cylindrical and has electrical insulation, the pilot arc is prevented from being ignited at a place other than between the electrode 3 and the plasma nozzle 8. In the present embodiment, the centering stone 9 has a plasma gas channel PG (axial channel PG1), which will be described later, formed in the axial direction (see FIG. 4). Inside the plasma nozzle 8, a plasma gas is supplied around the electrode 3, and the plasma gas is ejected from the plasma ejection holes 8a.

  At the tip of the torch body 2, a shield gas cup 11 is provided around the plasma nozzle 8 via a nozzle holder 10. The shield gas cup 11 has heat resistance, surrounds the tip of the plasma nozzle 8, and is screwed to the nozzle holder 10.

  As shown in FIGS. 4 and 5, the plasma welding torch 1 is provided with a cooling water passage W, a shield gas passage SG, and a plasma gas passage PG. The cooling water flow path W is provided in the torch body 2 and the plasma nozzle 8. The shield gas flow path SG is provided in the torch body 2 and the nozzle holder 10. The shield gas flow path SG is located outside the cooling water flow path W with respect to the electrode 3. The plasma gas flow path PG is provided in the centering stone 9 into which the electrode 3 is inserted.

  4 and 5, the flow of cooling water in the cooling water flow path W is indicated by solid arrows, the flow of shield gas in the shielding gas flow paths SG is indicated by dotted arrows, and the flow of plasma gas in the plasma gas flow paths PG Is indicated by a two-dot chain arrow.

  As shown in FIGS. 4, 6, and 7, the cooling water flow path W includes axial flow paths W1, W3, W5, W7, radial flow paths W2, W6, and an inclined flow path W4. The axial flow paths W <b> 1, W <b> 3, W <b> 5, W <b> 7 are provided along the axial center direction of the electrode 3. The radial flow paths W2 and W6 are provided along the radial direction of the electrode 3.

  As shown in FIGS. 4 and 7B, the axial flow path W <b> 1 is provided in the torch body 2, and specifically reaches from the body fitting 21 to the pilot fitting 22. The proximal end portion of the radial flow path W2 communicates with the distal end portion of the axial flow path W1, and as shown in FIG. 6 (d), the pilot fitting 22 is connected to the plasma nozzle 8 toward the radial inner side. It reaches. The pilot fitting 22 is configured by integrally joining a plurality of cylindrical members by brazing or the like, for example, and a part of the cooling water flow path W (the axial flow path) using the inner peripheral wall of the pilot fitting 22 W1 and radial flow path W2) are formed. As shown in FIGS. 4, 6 </ b> C, and 6 </ b> B, the axial flow path W <b> 3 extends in the direction toward the tip side of the electrode 3 in the plasma nozzle 8. The distance between the axial flow path W3 and the electrode 3 is shorter than the distance between the axial flow path W1 and the electrode 3. The base end of the inclined channel W4 is in communication with the tip of the axial channel W3. As shown in FIG. 6A, the inclined channel W4 is ring-shaped around the electrode 3 in the tip of the plasma nozzle 8. Is provided.

  The axial direction flow path W5 has the base end part connected to the inclined flow path W4, and the direction toward the base end side of the electrode 3 in the plasma nozzle 8 as shown in FIGS. 4 and 6C. It extends to. The proximal end portion of the radial flow path W6 communicates with the distal end portion of the axial flow path W5. As shown in FIG. 6 (d), the plasma nozzle 8 is connected to the pilot fitting 22 outward in the radial direction. It reaches. The axial direction flow path W7 has the base end part connected to the radial direction flow path W6. As shown in FIGS. 4 and 7B, the axial flow path W <b> 7 is provided in the torch body 2, and specifically reaches from the pilot fitting 22 to the body fitting 21. The distance between the axial flow path W7 and the electrode 3 is longer than the distance between the axial flow path W5 and the electrode 3. That is, in other words, the distance between the axial flow path W5 and the electrode 3 is shorter than the distance between the axial flow path W7 and the electrode 3.

  As shown in FIGS. 4 to 7, the shield gas flow path SG has axial flow paths SG1 and SG3 and a radial flow path SG2. The axial flow paths SG <b> 1 and SG <b> 3 are provided along the axial center direction of the electrode 3. The radial flow path SG2 is provided along the radial direction of the electrode 3.

  The axial flow path SG <b> 1 is provided in the torch body 2. As shown in FIG. 6D, in the present embodiment, a plurality of axial flow paths SG1 are provided. These axial flow paths SG <b> 1 are separated from each other in the circumferential direction around the axis of the electrode 3. The plurality of axial flow paths SG <b> 1 are configured by a plurality of grooves 22 a formed separately in the circumferential direction on the outer peripheral wall of a pilot fitting 22 (metal cylindrical member) that constitutes the torch body 2. In the present embodiment, the plurality of axial flow paths SG <b> 1 are evenly arranged radially in the circumferential direction of the pilot fitting 22. As shown in FIGS. 4 and 5, these axial flow paths SG <b> 1 communicate with the annular chamber portion 22 b connected to the shield gas introduction port 24, respectively, and are branched from each other in the axial direction of the electrode 3. It extends. Each axial flow path SG1 corresponds to a shield gas branch path in the present invention. The chamber portion 22b is configured by an annular groove formed in the outer peripheral wall of the pilot fitting 22.

  The proximal end portion of the radial flow path SG2 communicates with the distal end portion of the axial flow path SG1, and as shown in FIG. 7A, the radial flow path SG2 is annular around the electrode 3 and faces radially inward. From the pilot fitting 22 to the nozzle holder 10.

  As shown in FIGS. 4 and 5, the axial flow path SG <b> 3 is provided in the nozzle holder 10. As shown in FIG. 6C, in the present embodiment, a plurality of (8 in the present embodiment) axial flow paths SG3 are provided, and each base end portion communicates with the radial flow path SG2. ing. These axial flow paths SG3 are separated from each other in the circumferential direction around the axis of the electrode 3. The plurality of axial flow paths SG <b> 3 are configured by shield gas holes 10 b formed in the axial direction inside the nozzle holder 10. In the present embodiment, the plurality of axial flow paths SG <b> 3 are evenly arranged radially in the circumferential direction of the nozzle holder 10. Each of these axial flow channels SG3 is in communication with the annular radial flow channel SG2, and is branched from each other and extends in the axial direction of the electrode 3. Each axial flow path SG3 corresponds to a shield gas branch path in the present invention. The distance between the axial flow path SG3 and the electrode 3 is shorter than the distance between the axial flow path SG1 and the electrode 3.

  At the tip of the nozzle holder 10, a plurality of shield gas ejection ports 10a communicating with the plurality of axial flow paths SG3 are formed, respectively. FIG. 6B shows a case where eight shield gas ejection ports 10a are formed.

  As shown in FIGS. 4 to 7, the plasma gas flow path PG has an axial flow path PG1. The axial flow path PG <b> 1 is provided along the axial center direction of the electrode 3. The axial flow path PG <b> 1 is provided in the centering stone 9. As shown in FIGS. 6C, 6D, 7A, and 7B, in the present embodiment, a plurality (six in this embodiment) of axial flow paths PG1 are provided. . These axial flow paths PG <b> 1 are separated from each other in the circumferential direction around the axis of the electrode 3. The plurality of axial flow paths PG1 are constituted by a plurality of grooves 9a formed by being separated in the circumferential direction on the inner peripheral wall of the centering stone 9 (insulating cylindrical member). In the present embodiment, the plurality of axial flow paths PG <b> 1 are evenly arranged radially in the circumferential direction of the centering stone 9. These axial flow paths PG <b> 1 are branched from each other and extend in the axial direction of the electrode 3. Each axial flow path PG1 corresponds to a plasma gas branch path in the present invention.

  Next, the operation of this embodiment will be described.

  When the plasma welding torch 1 is used, cooling water is supplied to the plasma welding torch 1 via a welding power source (not shown) from a cooling water circulation device (not shown) by a conduit cable (not shown). Plasma gas and shield gas are supplied to the plasma welding torch 1 from a plasma gas cylinder (not shown) and a shield gas cylinder (not shown) via a conduit cable (not shown) via a welding power source (not shown). The electrode 3 as a cathode is discharged, and a main plasma arc is generated. The plasma gas supplied from the base end portion of the torch body 2 is supplied to the plasma gas channel PG (axial channel PG1) around the electrode 3, and the plasma gas is ejected from the plasma ejection hole 8a of the plasma nozzle 8. Is done. The cooling water supplied from the base end portion of the torch body 2 is supplied to the cooling water flow path W (the axial flow path W1 to the axial flow path W7), and the plasma nozzle 8 is cooled. The cooling water that has passed through the axial flow path W7 is returned to the cooling water circulation device (not shown) via a conduit cable (not shown) via a welding power source (not shown).

  The plasma gas is constrained by the water-cooled plasma nozzle 8 and the gas flow of the plasma gas, whereby a high-concentration high-temperature plasma flow is generated, and plasma welding is performed using this retained energy. The shield gas supplied to the torch body 2 is supplied via the shield gas flow path SG (axial flow path SG1 to axial flow path SG3). Then, the shield gas is ejected from the plurality of shield gas ejection ports 10 a formed at the distal end portion of the nozzle holder 10 and ejected from the distal end portion of the shield gas cup 11. The shielding gas shields the plasma arc, the molten pool and its surroundings from the atmosphere.

  In the present embodiment, the shield gas flow path SG has a plurality of axial flow paths SG1 and a plurality of axial flow paths SG3 that are separated in the circumferential direction around the axis of the electrode 3. According to such a configuration, unlike the case where an annular flow path is provided, for example, the member for forming the shield gas flow path SG (the pilot fitting 22 for the axial flow path SG1 and the nozzle for the axial flow path SG3) In the holder 10), voids can be reduced. As a result, the strength of the member forming the shield gas flow path SG can be improved as compared with the case where the annular flow path is provided extending in the axial direction. In addition, according to the configuration having a plurality of axial flow paths SG1 and SG3, the member forming the shield gas flow path SG in the radial direction while securing a predetermined strength as compared with the case where the annular flow path is provided. The size can be reduced. Such a configuration is suitable for reducing the size of the tip of the plasma welding torch 1.

  In the shield gas flow path SG, the plurality of axial flow paths SG1 includes a plurality of grooves 22a formed by being separated in the circumferential direction at the outer peripheral wall of the pilot fitting 22 (metal tubular member) constituting the torch body 2. Consists of. According to such a configuration, since the flow paths are formed between the grooves 22a and the adjacent member (the plastic cover 23 in the present embodiment) so as to close the grooves 22a, a plurality of axial flow paths are formed. SG1 can be easily formed.

  The plurality of axial flow paths SG <b> 1 are evenly arranged radially in the circumferential direction of the pilot fitting 22. Such a configuration is more preferable for the pilot fitting 22 in order to reduce the radial dimension while ensuring the strength.

  In the pilot fitting 22, a plurality of axial flow paths SG1 (shield gas flow paths SG) are formed on the outer peripheral wall, and a cooling water flow path W (axial flow path W1) is formed on the inner peripheral wall. According to such a configuration, the cylindrical wall of the pilot fitting 22 serves both as a shield gas supply path and as a cooling water supply path. Therefore, according to such a configuration, the radial dimension of the pilot fitting 22 can be further reduced, which is more preferable in reducing the size of the tip of the plasma welding torch 1.

  A plasma gas flow path PG is provided in the centering stone 9 into which the electrode 3 is inserted, and the plasma gas flow path PG has a plurality of axial flow paths PG1. These axial flow paths PG <b> 1 are configured by grooves 9 a formed on the inner peripheral wall of the centering stone 9 so as to be separated in the circumferential direction. According to such a configuration, unlike the case where, for example, an annular flow path is provided, gaps can be reduced in the member (centering stone 9) for forming the plasma gas flow path PG. As a result, the strength of the member forming the plasma gas flow path PG can be improved as compared with the case where the annular flow path extending in the axial direction is provided. In addition, according to the configuration having the plurality of axial flow paths PG1, the member (centering stone 9) forming the plasma gas flow path PG has a predetermined strength as compared with the case where the annular flow path is provided. The radial dimension can be reduced. Such a configuration is suitable for reducing the size of the tip of the plasma welding torch 1.

  Regarding the cooling water flow path W, the distance between the axial flow path W3 (W5) near the tip of the torch body 2 and the electrode 3 is the same as the axial flow path W1 (W7) and the electrode near the base end of the torch body 2. Shorter than 3 distance. For the shield gas flow path SG, the distance between the axial flow path SG3 near the tip of the torch body 2 and the electrode 3 is the same as the distance between the axial flow path SG1 and the electrode 3 near the base end of the torch body 2. Shorter than distance. Therefore, each of the cooling water flow path W and the shield gas flow path SG has a portion closer to the distal end of the torch body 2 closer to the axial center of the electrode 3 than a portion closer to the proximal end of the torch body 2. 1 is provided so as to approach the electrode 3 stepwise in the direction of the tip. According to such a structure, the diameter of the front-end | tip part of the plasma welding torch 1 can be made small, and size reduction of the plasma welding torch 1 can be achieved.

  As described above, the plasma welding torch 1 of the present embodiment can reduce the size of the tip portion. Specifically, for example, when the rated current is 350 [A] and the usage rate is 70 [%], the plasma Compared with the conventional plasma welding torch, the diameter of the tip of the welding torch 1 could be reduced by about 20 [%]. As a result, according to the plasma welding torch 1 of the present embodiment, interference with the workpiece can be reduced, and the plasma welding torch 1 can be easily approached to a narrow portion of the workpiece. Thus, the operability of the plasma welding torch 1 can be greatly improved.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to the above-described embodiments, and all modifications within the scope of the matters described in the claims are all within the scope of the present invention. Is included.

1 Plasma welding torch 2 Torch body 21 Body fitting 22 Pilot fitting (metal tubular member)
22a Groove 22b Chamber part 23 Plastic cover 24 Shield gas introduction port 3 Electrode 4 Collet 5 Collet body 6 Insulating bush 7 Cap 8 Plasma nozzle 8a Plasma ejection hole 9 Centering stone (insulating cylindrical member)
9a Groove 10 Nozzle holder 10a Shield gas outlet 10b Shield gas hole 11 Shield gas cup PG Plasma gas channel PG1 Axial channel (plasma gas branch)
SG Shield gas flow path SG1 Axial flow path (shield gas branch)
SG2 radial channel SG3 axial channel (shield gas branch)
W Cooling water flow path W1, W3, W5, W7 Axial flow path W2, W6 Radial flow path W4 Inclined flow path

Claims (4)

Torch body,
An electrode provided at the axial center of the torch body;
A plasma nozzle provided around the tip side of the electrode and supplied with a plasma gas;
A shield gas cup provided through a nozzle holder around the plasma nozzle at the tip of the torch body;
A cooling water flow path provided in the torch body and the plasma nozzle;
A shield gas flow path provided in the torch body and the nozzle holder outside the cooling water flow path,
The shielding gas flow path have a plurality of shielding gas branch path to separate the axial center of the circumferential direction of the electrode,
The plurality of shield gas branch paths are configured by a plurality of grooves formed by being separated in the circumferential direction at the outer peripheral wall of the metal cylindrical member constituting the torch body,
A plasma welding torch in which the cooling water flow path is formed on an inner peripheral wall of the metal cylindrical member . 2. The plasma welding torch according to claim 1 , wherein the plurality of shield gas branch paths are uniformly arranged radially in a circumferential direction of the metal cylindrical member. An insulating cylindrical member into which the electrode is inserted;
A plasma gas flow path provided in the insulating cylindrical member,
3. The plasma welding according to claim 1, wherein the plasma gas flow path has a plurality of plasma gas branch paths configured by grooves formed separately in a circumferential direction on an inner peripheral wall of the insulating cylindrical member. torch. The cooling water flow channel and the shield gas passage, respectively, the tip side of the portion of the torch body is in the axial center close to the electrode than the portion of the proximally of the torch body, claims 1 3 The plasma welding torch according to any one of the above.

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