welding torch

Abstract

To provide a welding torch suitable for miniaturization and simplification of structure. [Solution] The welding torch A1 comprises an electrode 25 extending in the axial direction z, a first member 26 positioned outside the electrode 25, a nozzle 30 positioned outside the electrode 25, and a locking member 33 fitted over the first member 26 and the nozzle 30, and engaging with both the first member 26 and the nozzle 30. The nozzle 30 includes a cylindrical nozzle small diameter portion 301 fitted concentrically to the electrode 25, a cylindrical nozzle main portion 302 positioned on the z1 side relative to the nozzle small diameter portion 301 and having a larger inner diameter than the nozzle small diameter portion 301, and a nozzle bulge portion 303 that bulges radially outward from the nozzle small diameter portion 301. The nozzle 30 is prevented from moving towards z2 by the z2 end abutting against the z1 end of the first member 26, and is prevented from moving towards z1 by the nozzle bulge portion 303 and the intermediate step portion 333 abutting against each other.

Description

Technical Field

[0001] The present disclosure relates to a welding torch.

Background Art

[0002] In welding performed using a welding torch having a non-consumable electrode (TIG welding method or plasma welding method), an arc is usually generated between an electrode (non-consumable electrode) formed of tungsten and a workpiece, and the workpiece is melted by the heat of the arc. In the TIG welding method, a shielding gas is flowed between the gas nozzle and the electrode. In the plasma welding method, in addition to the shielding gas, a plasma gas is flowed inside an insert tip disposed around the electrode, thereby confining the arc (plasma arc). As a result, a highly concentrated high-temperature plasma flow is generated, and welding is performed using the energy possessed by the plasma flow.

[0003] When welding a metal having a relatively low melting point (low melting metal) such as a galvanized steel sheet, zinc vapor and fumes are generated by the welding heat. When a metal such as fumes adheres to the electrode, the arc generated during welding becomes unstable. In the TIG welding method, usually, the tip of the electrode protrudes from the tip of the nozzle, and if the tip of the electrode is covered with a metal such as fumes, there is a risk of poor ignition at the start of welding. In the plasma welding method, usually, the tip of the electrode retreats from the tip of the insert tip surrounding the electrode. Also, a plasma gas is flowed inside the insert tip (around the electrode). Therefore, when welding a low melting metal such as a galvanized steel sheet, in the plasma welding method, a metal such as fumes is less likely to adhere to the electrode than in the TIG welding method. On the other hand, in the plasma welding method, a metal such as the above fumes may adhere to the tip of the insert tip, and when this happens, it alloyizes with the tip of the insert tip. Alloying of the tip of the insert tip may cause arc defects and welding defects.

[0004] Patent Document 1 discloses a configuration in which multiple side plasma gas ejection holes, consisting of small-diameter holes, are provided around the plasma gas ejection hole at the tip of the insert tip. By providing these additional side plasma gas ejection holes, the adhesion of fumes and other substances to the tip of the insert tip during welding is reduced. However, the structure described in Patent Document 1 results in a complex insert tip structure and leads to an enlargement of the tip of the insert tip (welding torch). Furthermore, if the axis of the insert tip, which is positioned with a gap around the electrode, is misaligned with the electrode's axis, the plasma gas ejected from the tip of the insert tip may become unevenly flowed, potentially leading to a decrease in welding quality.

[0005] Patent Document 2 discloses a welding torch comprising a cylindrical inner nozzle positioned radially outside the electrode, a cylindrical locking member for locking the inner nozzle, and a cylindrical electrode centering member positioned radially outside the electrode and radially inside the inner nozzle. The electrode centering member is fitted concentrically to the electrode. According to the configuration shown in Patent Document 2, the inner nozzle can be positioned concentrically with respect to the electrode by providing the electrode centering member. However, the structure described in Patent Document 2 has an increased number of parts because it includes an electrode centering member in addition to the inner nozzle. Furthermore, there are disadvantages such as the risk of damage to the inner nozzle, which is made of an insulating material, when replacing the electrode. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2009-172644 [Patent Document 2] Japanese Patent Publication No. 2024-65576 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] This disclosure was conceived under these circumstances, and its primary objective is to provide a welding torch suitable for simplifying and miniaturizing its structure. [Means for solving the problem]

[0008] To address the above challenges, this disclosure employs the following technical measures.

[0009] The welding torch provided by this disclosure includes a non-consumable electrode extending in the axial direction, a cylindrical first member disposed radially outside the non-consumable electrode, a cylindrical first nozzle disposed radially outside the non-consumable electrode and on one side in the axial direction relative to the first member, a cylindrical locking member fitted over the first member and the first nozzle and engaging with both the first member and the first nozzle, the first nozzle comprising a cylindrical nozzle small diameter portion concentrically fitted over the non-consumable electrode, a cylindrical nozzle main portion located on one side in the axial direction relative to the nozzle forming portion and having an inner diameter larger than the nozzle small diameter portion, and the nozzle The locking member includes a nozzle bulge portion that bulges radially outward from a small diameter portion, and the locking member includes a large diameter cylindrical portion that is fitted onto the nozzle bulge portion, a small diameter cylindrical portion that has a smaller inner diameter than the large diameter cylindrical portion and is fitted onto the main part of the nozzle, and an intermediate stepped portion that connects to both the large diameter cylindrical portion and the small diameter cylindrical portion, wherein the first nozzle is prevented from moving to the other side in the axial direction by the second end on the other side in the axial direction of the first nozzle abutting against the first end on one side in the axial direction of the first member, and the first nozzle is prevented from moving to one side in the axial direction by the nozzle bulge portion and the intermediate stepped portion abutting against each other.

[0010] In a preferred embodiment, the first nozzle includes an intermediate cylindrical portion located between the small diameter portion of the nozzle and the main portion of the nozzle in the axial direction, and connected to both the small diameter portion of the nozzle and the main portion of the nozzle, wherein the inner circumferential surface of the intermediate cylindrical portion is inclined such that its inner diameter decreases toward the other side in the axial direction.

[0011] In a preferred embodiment, the first end has a first contact surface, and the second end has a second contact surface that contacts the first contact surface, and each of the first and second contact surfaces is inclined such that its radial dimension increases toward one side in the axial direction.

[0012] In a preferred embodiment, the nozzle bulge portion has a third contact surface located on one side in the axial direction, the intermediate step portion has a fourth contact surface that contacts the third contact surface, and each of the third and fourth contact surfaces is inclined such that its radial dimension decreases as it moves toward one side in the axial direction.

[0013] In a preferred embodiment, the large-diameter cylindrical portion of the locking member and the first end of the first member are connected by a screw.

[0014] In a preferred embodiment, the first nozzle is made of an insulating material.

[0015] In a preferred embodiment, the system further includes a cylindrical second nozzle positioned radially outward from the first nozzle and the locking member. [Effects of the Invention]

[0016] In the welding torch according to the present disclosure, the nozzle small-diameter portion of the first nozzle and the nozzle main portion integrally formed therewith are arranged concentrically with respect to the non-consumable electrode. The locking member is externally fitted across the first member and the first nozzle and locks to both the first member and the first nozzle. According to such a configuration, a certain degree of flexibility can be provided in the radial direction between the locking member and the first member or the first nozzle. Therefore, for example, even if the non-consumable electrode is slightly bent due to manufacturing errors or the like, the first nozzle can be arranged concentrically with respect to the non-consumable electrode. Further, the first nozzle includes a nozzle small-diameter portion having a function of electrode centering and a nozzle main portion capable of forming a gas flow path between the nozzle small-diameter portion and the non-consumable electrode, and these nozzle small-diameter portion and nozzle main portion are constituted by one component. Thereby, while providing the function of electrode centering in the first nozzle, an increase in the number of components can be prevented. Therefore, in the welding torch of the present disclosure, simplification and miniaturization of the structure can be achieved.

[0017] Other features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings.

Brief Description of the Drawings

[0018] [Figure 1] It is a front view showing an example of the welding torch according to the present disclosure. [Figure 2] It is a plan view of the welding torch shown in FIG. 1. [Figure 3] It is a cross-sectional view taken along line III-III of FIG. 2. [Figure 4] It is a cross-sectional view taken along line IV-IV of FIG. 3. [Figure 5] It is an enlarged cross-sectional view taken along line V-V of FIG. 3. [Figure 6] It is an enlarged cross-sectional view taken along line VI-VI of FIG. 3. [Figure 7] It is an enlarged cross-sectional view taken along line VII-VII of FIG. 3. [Figure 8] It is a partial enlarged view of FIG. 3. [Figure 9] It is a perspective view of the inner nozzle. [Figure 10] It is a longitudinal sectional view of the inner nozzle. [Figure 11] It is a cross-sectional view similar to FIG. 8 showing a modified example of the welding torch according to the present disclosure. [Figure 12] It is a cross-sectional view similar to FIG. 8 showing another modified example of the welding torch according to the present disclosure.

Mode for Carrying Out the Invention

[0019] Hereinafter, preferred embodiments of the present disclosure will be specifically described with reference to the drawings. In the following description, terms such as "first" and "second" are merely used as labels and are not necessarily intended to assign an order to their objects.

[0020] FIGS. 1 to 8 show an example of a welding torch according to the present disclosure. The welding torch A1 of the present embodiment includes a handle 1, a torch body 2, insulating rings 23, 24, a non-consumable electrode 25, a collet body 26, a collet 27, a collet pressing member 28, a cap 29, an inner nozzle 30, an outer nozzle 31, a nozzle holder 32, a locking member 33, a first gas pipe 41, a second gas pipe 42, a first cooling water pipe 43, and a second cooling water pipe 44. The welding torch A1 of the present embodiment is configured to be held by an operator's hand to perform a welding operation. Further, although details will be described later, in the welding torch A1, two gas flow paths (a first gas flow path G1 and a second gas flow path G2) for flowing a predetermined welding gas are formed.

[0021] In the description of the welding torch A1, the vertical direction in the drawings in FIGS. 1 and 3 is an example of the "axial direction" of the present disclosure and is referred to as the "axial direction z". The direction orthogonal to the axial direction z in FIG. 3 (the left-right direction in the drawing) is referred to as the "first direction x". Further, the lower side in the drawings in FIGS. 1 and 3 is an example of the "one side of the axial direction" of the present disclosure and is referred to as the "one side of the axial direction z1", and the upper side in the drawings is an example of the "other side of the axial direction" of the present disclosure and is referred to as the "other side of the axial direction z2".

[0022] Handle 1 is the part that the worker grips with their hand. As shown in Figure 3, Handle 1 is a cylindrical member made of an insulating material.

[0023] The torch body 2 is cylindrical, with its end held by the handle 1. The torch body 2 includes a body body 20, a cylindrical member 21, and a cylindrical member 22. The body body 20 appropriately houses the components of the welding torch A1 inside. The body body 20 is made of an insulating material. The body body 20 has a first cylindrical portion 20A and a second cylindrical portion 20B.

[0024] The first cylindrical portion 20A extends along the axial direction z. The second cylindrical portion 20B is branched off from the first cylindrical portion 20A. The second cylindrical portion 20B extends in a direction intersecting the axial direction z (upper right direction in Figure 3). In the illustrated example, the angle between the direction in which the first cylindrical portion 20A extends (axial direction z) and the direction in which the second cylindrical portion 20B extends is approximately 65°. Note that the angle between the direction in which the first cylindrical portion 20A extends (axial direction z) and the direction in which the second cylindrical portion 20B extends is not particularly limited and may be, for example, a right angle (90°). The end of the second cylindrical portion 20B (upper right end in Figure 3) is held by the end of the handle 1. In the illustrated example, the end of the second cylindrical portion 20B and the end of the handle 1 are fixed to each other by a screw connection.

[0025] The cylindrical member 21 is positioned radially inward of the first cylindrical portion 20A. The cylindrical member 21 is a component that receives power from a power supply unit (not shown) and is made of a conductive material. Copper is an example of the conductive material that constitutes the cylindrical member 21. As shown in Figures 3 and 4, the cylindrical member 21 has a first gas inlet 211, a second gas inlet 212, and a groove 213. The cylindrical member 22 is positioned radially outward of the cylindrical member 21. Details of the cylindrical members 21 and 22 will be described later.

[0026] The insulating rings 23 and 24 are cylindrical members made of insulating material. The insulating ring 23 is positioned adjacent to the first cylindrical portion 20A on the other side z2 in the axial direction. The insulating ring 24 is positioned adjacent to the second cylindrical portion 20B on one side z1 in the axial direction.

[0027] The non-consumable electrode 25 is a rod-shaped conductor extending along the axial direction z (the direction in which the axis CL extends). The non-consumable electrode 25 is made of, for example, tungsten. The non-consumable electrode 25 is connected to a power supply unit (not shown) via, for example, a conduit cable (not shown), and generates an arc between the electrode and the workpiece when an arc voltage is applied between the electrode and the workpiece.

[0028] The non-consumable electrode 25 has an electrode main portion 251 and an electrode tapered portion 252. The electrode main portion 251 is a part with a constant outer diameter and occupies most of the non-consumable electrode 25 excluding the tip. The electrode main portion 251 is a part that is formed in a substantially cylindrical shape so that the outer diameter is constant in the design, and may contain some manufacturing errors. The outer diameter of the electrode main portion 251 is not particularly limited, and in this embodiment, for example, it is about 1.6 to 4.0 mm. The electrode tapered portion 252 is connected to the electrode main portion 251 on the tip side (one side z1 in the axial direction) of the non-consumable electrode 25. The electrode tapered portion 252 has a diameter that decreases towards the tip side (one side z1 in the axial direction) of the non-consumable electrode 25 and is substantially conical in shape.

[0029] The collet body 26, collet 27, and collet retaining member 28 cooperate with each other to hold the non-consumable electrode 25. The collet body 26, collet 27, and collet retaining member 28 are made of a conductive material. Copper is an example of the conductive material that makes up the collet body 26, collet 27, and collet retaining member 28.

[0030] The collet 27 surrounds the non-consumable electrode 25. The collet body 26 is cylindrical and is positioned radially outward of the collet 27. The collet body 26 is also positioned radially inward of the cylindrical member 21. Detailed illustrations are omitted, but the collet body 26 is fixed to the cylindrical member 21 by means of a screw connection, for example. As shown in Figure 8, a first contact surface 262a is formed on the inner circumference of the end (first end) on one side z1 in the axial direction of the collet body 26. The first contact surface 262a is a tapered surface that slopes so that its radial dimension increases towards the one side z1 in the axial direction, and it connects to the end edge of the one side z1 in the axial direction of the collet body 26.

[0031] The collet retaining member 28 is positioned on the other axial side z2 relative to the collet 27. Although detailed illustrations are omitted, the collet retaining member 28 has a male thread that is screwed into the cylindrical member 21. A female thread is formed at the upper end of the cylindrical member 21 (the end on the other axial side z2), and the male thread of the collet retaining member 28 is screwed into this female thread. A cap 29 is provided on the other axial side z2 of the collet retaining member 28. By rotating this cap 29, the position of the collet retaining member 28 in the axial direction z relative to the collet body 26 can be adjusted. The end of the collet retaining member 28 on one axial side z1 abuts against the end of the collet 27 on the other axial side z2. When the collet retaining member 28 is moved to one axial side z1, the collet 27 is pressed against one axial side z1.

[0032] The collet 27 has multiple slits extending in the axial direction z at its tip end (one side z1 in the axial direction), and has multiple movable pieces 271 positioned between adjacent slits. As described above, when the collet retaining member 28 is moved to one side z1 in the axial direction, the collet 27 is pressed against that side z1. Then, the multiple movable pieces 271 at the tip of the collet 27 are pressed against the tip of the collet body 26, reducing its diameter, and the collet 27 holds the non-consumable electrode 25 between them. In this way, the non-consumable electrode 25 is held by the cooperation of the collet body 26, the collet 27, and the collet retaining member 28.

[0033] As shown in Figure 3, the inner nozzle 30 is positioned around the tip of the non-consumable electrode 25 (the end on one side z1 in the axial direction). The inner nozzle 30 is positioned on one side z1 in the axial direction relative to the collet body 26. The inner nozzle 30 is cylindrical and is positioned radially outward of the non-consumable electrode 25 (electrode main portion 251).

[0034] As shown in Figures 8 to 10, the inner nozzle 30 includes a nozzle small diameter portion 301, a nozzle main portion 302, a nozzle bulge portion 303, and an intermediate cylindrical portion 304. In this embodiment, the inner nozzle 30 also has a plurality of through holes 305. Figure 9 is a perspective view of the inner nozzle 30, and Figure 10 is a longitudinal cross-sectional view of the inner nozzle 30. Figure 10(a) shows a cutting position in which the through holes 305 are visible on the cut surface, and Figure 10(b) shows a cutting position in which the through holes 305 are not visible on the cut surface.

[0035] The nozzle small-diameter portion 301 is located towards the other side z2 in the axial direction and is roughly cylindrical in shape. The inner diameter of the nozzle small-diameter portion 301 (see inner diameter d1 in Figure 10) is slightly larger than the outer diameter of the non-consumable electrode 25 (electrode main portion 251). As a result, the nozzle small-diameter portion 301 (inner nozzle 30) is concentrically fitted onto the non-consumable electrode 25.

[0036] The nozzle small diameter portion 301 (inner nozzle 30) has a second contact surface 301a. In the illustrated example, the second contact surface 301a is formed on the outer circumference of the end (second end) on the other axial side z2 of the inner nozzle 30, and is a tapered surface that inclins so that the radial dimension increases towards the one axial side z1. This second contact surface 301a is in contact with the first contact surface 262a of the collet body 26.

[0037] The nozzle main portion 302 is located on one side z1 in the axial direction relative to the nozzle small diameter portion 301. The nozzle main portion 302 is cylindrical, and its inner diameter is larger than the inner diameter (d1) of the nozzle small diameter portion 301. The nozzle main portion 302 extends on one side z1 in the axial direction. The central axis of the nozzle main portion 302 coincides with or approximately coincides with the central axis of the nozzle small diameter portion 301.

[0038] The nozzle bulge portion 303 bulges radially outward from the nozzle small diameter portion 301. The nozzle bulge portion 303 has a third contact surface 303a. The third contact surface 303a is formed on the outer circumference of one side z1 in the axial direction of the nozzle bulge portion 303 and is a tapered surface that slopes so that the radial dimension decreases as it approaches one side z1 in the axial direction.

[0039] The intermediate cylindrical portion 304 is located between the nozzle small diameter portion 301 and the nozzle main portion 302 in the axial direction z, and connects to both the nozzle small diameter portion 301 and the nozzle main portion 302. The inner circumferential surface of the intermediate cylindrical portion 304 is a tapered surface that slopes such that the inner diameter dimension decreases towards the other side z2 in the axial direction. The inclination angle θ of the inner circumferential surface of the intermediate cylindrical portion 304 with respect to the axial direction z (see Figure 10(b)) is, for example, 10° or more and 50° or less, preferably 20° or more and 30° or less. In the illustrated example, the above inclination angle θ is approximately 30°.

[0040] Each of the multiple through-holes 305 extends in the axial direction z and is formed spanning from the nozzle small diameter portion 301 to a part of the nozzle main portion 302. The multiple through-holes 305 are provided at regular intervals in the circumferential direction of the inner nozzle 30. In the illustrated example, six through-holes 305 are formed in the inner nozzle 30. Each through-hole 305 constitutes the first gas flow path G1, which will be described later.

[0041] The inner nozzle 30 in the above configuration is made of an insulating material. The constituent material of the inner nozzle 30 is not particularly limited and includes, for example, ceramic materials such as alumina and resin materials such as heat-resistant phenol. The inner nozzle 30 corresponds to an example of the "first nozzle" in this disclosure.

[0042] As shown in Figure 8, the locking member 33 is fitted over both the collet body 26 and the inner nozzle 30.

[0043] The locking member 33 includes a large-diameter cylindrical portion 331, a small-diameter cylindrical portion 332, and an intermediate stepped portion 333. The large-diameter cylindrical portion 331 is located on the other side z2 in the axial direction and is fitted onto the nozzle bulge portion 303. The small-diameter cylindrical portion 332 has a smaller inner diameter than the large-diameter cylindrical portion 331. The small-diameter cylindrical portion 332 is located on one side z1 in the axial direction and is fitted onto the nozzle main portion 302. The intermediate stepped portion 333 is located between the large-diameter cylindrical portion 331 and the small-diameter cylindrical portion 332 in the axial direction z and connects to both the large-diameter cylindrical portion 331 and the small-diameter cylindrical portion 332. The large-diameter cylindrical portion 331 has a female threaded portion 331a. The female threaded portion 331a is formed on the inner circumference of the large-diameter cylindrical portion 331. The intermediate stepped portion 333 has a fourth contact surface 333a. The fourth contact surface 333a is formed on the inner circumference of the intermediate step portion 333. The fourth contact surface 333a is a tapered surface that slopes such that its radial dimension decreases as it moves toward one side z1 in the axial direction. The fourth contact surface 333a is in contact with the third contact surface 303a of the nozzle bulge portion 303. In the illustrated example, the locking member 33 has a cap nut structure.

[0044] In this embodiment, as shown in Figures 3 and 8, the locking member 33 (large diameter cylindrical portion 331) and the end (first end) on one axial side z1 of the collet body 26 are connected by a screw. For example, a male threaded portion 261a is formed on the outer circumference of the end (z1) on one axial side of the collet body 26, and a female threaded portion 331a formed on the locking member 33 (large diameter cylindrical portion 331) is screwed into the male threaded portion 261a of the collet body 26. On the other hand, as shown in Figure 8, the small diameter cylindrical portion 332 on one axial side z1 of the locking member 33 is fitted onto the main nozzle portion 302, and the nozzle bulge portion 303 (third contact surface 303a) and the intermediate step portion 333 (fourth contact surface 333a) are in contact with each other. As a result, the relative movement of the inner nozzle 30 and the locking member 33 in the axial direction z is restricted, and the movement of the inner nozzle 30 toward one side z1 in the axial direction is prevented. In addition, the end of the inner nozzle 30 toward the other side z2 in the axial direction (second end, second contact surface 301a) and the end of the collet body 26 toward one side z1 in the axial direction (first end, first contact surface 262a) are in contact. As a result, the relative movement of the inner nozzle 30 and the collet body 26 in the axial direction z is restricted, and the movement of the inner nozzle 30 toward the other side z2 in the axial direction is prevented. The collet body 26 in the above configuration corresponds to an example of the "first member" of this disclosure.

[0045] As shown in Figure 8, in this embodiment, the tip of the non-consumable electrode 25 coincides with the tip of the inner nozzle 30 in the axial direction z, or slightly protrudes from the tip of the inner nozzle 30 to one side z1 in the axial direction. The protrusion length P1 of the tip of the non-consumable electrode 25 protruding from the tip of the inner nozzle 30 to one side z1 in the axial direction is, for example, in the range of 0 to 2 mm.

[0046] The nozzle holder 32 is cylindrical in shape. The nozzle holder 32 is integrally connected to the outer circumference of the intermediate portion of the collet body 26 in the axial direction z by means of, for example, brazing.

[0047] As shown in Figures 3 and 8, the outer nozzle 31 is positioned radially outward of the inner nozzle 30. The outer nozzle 31 is positioned on one axial side z1 with respect to the first cylindrical portion 20A, and an insulating ring 24 is interposed between the outer nozzle 31 and the first cylindrical portion 20A. In the illustrated example, the outer nozzle 31 is generally cylindrical, with the tip side (one axial side z1) having a smaller diameter than other parts. In this embodiment, the outer nozzle 31 is positioned concentrically with respect to the non-consumable electrode 25 and the inner nozzle 30. The outer nozzle 31 is attached, for example, to the outer circumference of the nozzle holder 32 by screw connection. Note that the outer nozzle 31 corresponds to an example of the "second nozzle" in this disclosure.

[0048] As shown in Figure 8, in this embodiment, the tip of the inner nozzle 30 protrudes from the tip of the outer nozzle 31 in one axial direction z1. The protrusion length P2 of the tip of the inner nozzle 30 protruding from the tip of the outer nozzle 31 in one axial direction z1 is, for example, in the range of 0 to 5 mm.

[0049] As shown in Figures 3 to 8, in this embodiment, the welding torch A1 is formed with a first gas channel G1, a second gas channel G2, and a cooling water channel W.

[0050] In this embodiment, the welding gas supplied to the welding torch A1 includes two types of inert gases with different gas supply characteristics, such as gas type and flow rate. For the sake of explanation, these two types of inert gases will be appropriately referred to as "first inert gas" and "second inert gas."

[0051] The first gas flow path G1 is a flow path for the first inert gas. In Figures 3 and 8, the flow of the first inert gas is indicated by the dashed arrow. The first gas flow path G1 is formed between the collet 27 and the collet body 26, between the non-consumable electrode 25 (electrode main part 251) and the collet 27, between the non-consumable electrode 25 (electrode main part 251) and the collet body 26, in the inner nozzle 30 (multiple through holes 305), and between the non-consumable electrode 25 (electrode main part 251) and the inner nozzle 30 (nozzle main part 302).

[0052] In this embodiment, as shown in Figure 3, the torch body 2 (cylindrical member 21) is provided with a first gas inlet 211 for introducing a first inert gas. The first gas inlet 211 is connected to a first gas flow path G1. When the first inert gas is introduced from the first gas inlet 211, the first inert gas flows in the first gas flow path G1 from the other axial side z2 to the one axial side z1, passes between the non-consumable electrode 25 (electrode main part 251) and the inner nozzle 30, and is ejected from the opening 306 at the tip of the inner nozzle 30.

[0053] The second gas flow path G2 is a flow path for the second inert gas. In Figures 3 and 8, the flow of the second inert gas is indicated by dotted arrows. The second gas flow path G2 is formed between the collet body 26 and the cylindrical member 21, between the collet body 26 and the insulating ring 24, between the nozzle holder 32, the locking member 33 and the outer nozzle 31, and between the inner nozzle 30 and the outer nozzle 31, respectively.

[0054] In this embodiment, as shown in Figure 3, the torch body 2 (cylindrical member 21) is provided with a second gas inlet 212 for introducing a second inert gas. The second gas inlet 212 is connected to a second gas flow path G2. When the second inert gas is introduced from the second gas inlet 212, the second inert gas flows in the second gas flow path G2 from the other side z2 in the axial direction to the one side z1 in the axial direction, passes between the inner nozzle 30 and the outer nozzle 31, and is ejected from the opening 316 at the tip of the outer nozzle 31.

[0055] The cooling water channel W is a channel for the flow of cooling water. As shown in Figure 4, the cooling water channel W is formed along the circumferential direction of the non-consumable electrode 25. The cooling water channel W is mainly formed between the cylindrical member 21 and the cylindrical member 22.

[0056] Referring to Figures 3 and 4, the first gas inlet 211, the second gas inlet 212, and the groove 213 of the cylindrical member 21 will be described. The first gas inlet 211 is located on the other side z2 in the axial direction relative to the second gas inlet 212. The first gas inlet 211 is inclined with respect to the first direction x. The first gas inlet 211 is inclined so that as it approaches the non-consumable electrode 25 in the first direction x, it is located on one side z1 in the axial direction.

[0057] The second gas inlet 212 is inclined with respect to the first direction x. The second gas inlet 212 is inclined so that as it approaches the non-consumable electrode 25 in the first direction x, it is positioned on one side z1 in the axial direction. The first cylindrical portion 20A, located radially outward of the cylindrical member 21, is positioned to straddle the first gas inlet 211 and the second gas inlet 212 in the axial direction z.

[0058] The groove 213 is a portion of the outer surface of the cylindrical member 21 that is recessed radially inward. The cylindrical member 22 is generally cylindrical and is positioned radially outside the cylindrical member 21. The cylindrical member 22 blocks the groove 213 from the radially outside. As shown in Figure 4, in this embodiment, the cooling water flow path W is formed by the space between the groove 213 and the cylindrical member 22 that blocks it. In this embodiment, the cooling water flow path W is located between the first gas inlet 211 and the second gas inlet 212 in the axial direction z.

[0059] As shown in Figure 3, the first gas pipe 41 and the second gas pipe 42 pass through the inside of the second cylindrical section 20B. The first gas pipe 41 is a pipe that carries the first gas flow path G1 and is connected to the first gas inlet 211 of the cylindrical member 21. The second gas pipe 42 is a pipe that carries the second gas flow path G2 and is connected to the second gas inlet 212 of the cylindrical member 21. The second cylindrical section 20B has a constricted shape in which the portion closer to the first cylindrical section 20A has a smaller diameter than the portion closer to the handle 1. In the illustrated example, the first gas pipe 41 and the second gas pipe 42 are bent appropriately in accordance with this constricted shape of the second cylindrical section 20B. The end of the first gas pipe 41 that is connected to the first gas inlet 211 extends along the first direction x.

[0060] As shown in Figure 4, the first cooling water pipe 43 and the second cooling water pipe 44 are inserted inside the second cylindrical section 20B. In the illustrated example, the first cooling water pipe 43 is a pipe for supplying cooling water to the cooling water flow path W described above. The second cooling water pipe 44 is a pipe for sending the cooling water that has flowed through the cooling water flow path W to the outside. The end of the first cooling water pipe 43 on the first cylindrical section 20A side is connected to one end of the cooling water flow path W. The end of the second cooling water pipe 44 on the first cylindrical section 20A side is connected to the other end of the cooling water flow path W. As a result, as shown in Figure 4, the cooling water flows in the order of the first cooling water pipe 43, the cooling water flow path W, and the second cooling water pipe 44. In Figure 4, the flow of cooling water is represented by solid arrows.

[0061] The types of gases supplied to the welding torch A1, namely the first inert gas and the second inert gas, are not particularly limited and include, for example, at least one selected from argon (Ar) gas and helium (He) gas. The flow rates of the first and second inert gases supplied to the welding torch A1 are individually adjusted as appropriate depending on the welding conditions, etc.

[0062] As shown in Figure 8, the gap between the non-consumable electrode 25 (electrode main part 251) and the inner nozzle 30 (nozzle main part 302) in the first gas flow path G1 is smaller than the gap between the inner nozzle 30 (nozzle main part 302) and the outer nozzle 31 in the second gas flow path G2. The minimum gap L1 between the non-consumable electrode 25 (electrode main part 251) and the inner nozzle 30 (nozzle main part 302) in the first gas flow path G1 is, for example, about 0.4 to 1.8 mm. The minimum gap L2 between the inner nozzle 30 (nozzle main part 302) and the outer nozzle 31 in the second gas flow path G2 is, for example, about 1 to 4 mm. Regarding the ratio of the minimum gap L1 to the minimum gap L2, the minimum gap L1 is, for example, 0.2 to 0.5 times the minimum gap L2, and preferably 0.2 to 0.3 times the minimum gap L2.

[0063] Next, the operation of this embodiment will be described.

[0064] The welding torch A1 of this embodiment comprises a non-consumable electrode 25 extending in the axial direction z, a collet body 26 (first member), an inner nozzle 30 (first nozzle), and a locking member 33. The inner nozzle 30 has a nozzle small diameter portion 301, a nozzle main portion 302, and a nozzle bulge portion 303. The nozzle small diameter portion 301 is fitted concentrically to the non-consumable electrode 25. The nozzle main portion 302, which is integrally formed with the nozzle small diameter portion 301, is arranged concentrically with respect to the non-consumable electrode 25. The locking member 33 is fitted across the collet body 26 (first member) and the inner nozzle 30, and locks to both the collet body 26 and the inner nozzle 30. With this configuration, some radial flexibility can be provided between the locking member 33 and the collet body 26 or the inner nozzle 30. Therefore, even if the non-consumable electrode 25 is slightly bent due to manufacturing errors or the like, the inner nozzle 30 can be positioned concentrically with respect to the non-consumable electrode 25.

[0065] The inner nozzle 30 includes a nozzle small-diameter portion 301 that has the function of centering the electrode, and a nozzle main portion 302 that can form a first gas flow path G1 between itself and the non-consumable electrode 25. These nozzle small-diameter portion 301 and nozzle main portion 302 are made of a single part. This makes it possible to provide the electrode centering function in the inner nozzle 30 while preventing an increase in the number of parts. Therefore, the welding torch A1 of this embodiment can be made simpler and smaller in size.

[0066] If the inner nozzle 30 becomes misaligned with respect to the non-consumable electrode 25, a misflow occurs in the first inert gas (plasma gas) ejected from the opening 306 at the tip of the inner nozzle 30 (nozzle main portion 302). The minimum gap L1 between the non-consumable electrode 25 (electrode main portion 251) and the inner nozzle 30 (nozzle main portion 302) that constitute the first gas flow path G1 is narrow, and if the inner nozzle 30 becomes misaligned, it is likely to cause a misflow of the first inert gas (plasma gas). However, as described above, the structure, which includes a nozzle small-diameter portion 301 that has the function of centering the electrode and a locking member 33, ensures that the inner nozzle 30 (nozzle main portion 302) is positioned concentrically with respect to the non-consumable electrode 25. This is suitable for improving welding quality.

[0067] Furthermore, since the inner nozzle 30 is concentrically positioned radially outward of the non-consumable electrode 25, the gas (first inert gas) flowing through the first gas channel G1 between the non-consumable electrode 25 and the inner nozzle 30 becomes a nearly uniform and relatively high-speed airflow around the non-consumable electrode 25 and is ejected from the opening 306 at the tip of the inner nozzle 30. As a result, even when welding workpieces made of low-molten metal such as galvanized steel sheets, the high-speed airflow of the first inert gas flowing around the non-consumable electrode 25 blows away fumes and other contaminants generated during welding. Therefore, it is possible to prevent fumes and other contaminants from adhering to the tip of the non-consumable electrode 25 or the tip of the inner nozzle 30.

[0068] The inner nozzle 30 includes an intermediate cylindrical portion 304. The intermediate cylindrical portion 304 is located between the nozzle small diameter portion 301 and the nozzle bulge portion 303 in the axial direction z, and connects to both the nozzle small diameter portion 301 and the nozzle main portion 302. The inner circumferential surface of the intermediate cylindrical portion 304 is a tapered surface that slopes so that the inner diameter dimension decreases as it moves toward the other side z2 in the axial direction. When replacing the non-consumable electrode 25, the end of the non-consumable electrode 25 on the other side z2 in the axial direction is inserted into the inner nozzle 30 from one side z1 in the axial direction toward the other side z2. At this time, the end of the non-consumable electrode 25 on the other side z2 in the axial direction is guided by the inner circumferential surface (tapered surface) of the intermediate cylindrical portion 304, making it possible to smoothly insert the non-consumable electrode 25 into the inside of the nozzle small diameter portion 301. This makes it possible to avoid problems such as damage to the inner nozzle 30, which is made of an insulating material (such as a relatively brittle ceramic material).

[0069] The large-diameter cylindrical portion 331 of the locking member 33 and the end (first end) on one axial side z1 of the collet body 26 are connected by a screw. With this configuration, a reasonable amount of dimensional flexibility can be provided between the locking member 33 and the collet body 26 with a relatively simple structure. In addition, when replacing the inner nozzle 30, the inner nozzle 30 can be easily removed by loosening the female threaded portion 331a of the locking member 33, resulting in excellent workability for replacing the inner nozzle 30.

[0070] In the mounting structure of the inner nozzle 30 and the locking member 33, the end of the inner nozzle 30 on the other axial side z2 (second end) abuts against the end of the collet body 26 on one axial side z1 (first end). This prevents the inner nozzle 30 from moving to the other axial side z2. In addition, the nozzle bulge portion 303 of the inner nozzle 30 abuts against the intermediate step portion 333 of the locking member 33. This prevents the inner nozzle 30 from moving to the one axial side z1. With this configuration, when the female thread portion 331a of the locking member 33 (large diameter cylindrical portion 331) and the male thread portion 261a of the collet body 26 are tightened, the portion of the inner nozzle 30 on the other side z2 in the axial direction (part of the small diameter nozzle portion 301 and the nozzle bulge portion 303) is firmly held in place by compressive force acting from both sides in the axial direction z by the end portion z1 on one side z1 in the axial direction of the collet body 26 and the intermediate stepped portion 333 of the locking member 33.

[0071] In this embodiment, the end of the collet body 26 on one axial side z1 (first end) has a first contact surface 262a. The end of the inner nozzle 30 on the other axial side z2 (second end) has a second contact surface 301a that contacts the first contact surface 262a. Each of the first contact surface 262a and the second contact surface 301a is inclined such that its radial dimension increases towards the axial side z1. With this configuration, the alignment accuracy of the nozzle small diameter portion 301 (inner nozzle 30) with respect to the non-consumable electrode 25 can be improved.

[0072] In this embodiment, the nozzle bulge portion 303 of the inner nozzle 30 has a third contact surface 303a located on one side z1 in the axial direction. The intermediate step portion 333 of the locking member 33 has a fourth contact surface 333a that contacts the third contact surface 303a. Each of the third contact surface 303a and the fourth contact surface 333a is inclined such that its radial dimension decreases as it moves toward one side z1 in the axial direction. With this configuration, the alignment accuracy of the nozzle small diameter portion 301 (inner nozzle 30) with respect to the non-consumable electrode 25 can be further improved.

[0073] The inner nozzle 30 is made of an insulating material. The insulating material has a compressive strength higher than its tensile strength. In this embodiment, as described above, the female thread portion 331a of the locking member 33 (large diameter cylindrical portion 331) and the male thread portion 261a of the collet body 26 are tightened. As a result, the portion of the inner nozzle 30 on the other side z2 in the axial direction (part of the small diameter nozzle portion 301 and the nozzle bulge portion 303) is firmly held in place by the collet body 26 and the locking member 33 (intermediate step portion 333) acting with compressive force from both sides in the axial direction z. Such a configuration is preferable for increasing the durability of the inner nozzle 30.

[0074] In this embodiment, the outer nozzle 31 is positioned radially outward of the inner nozzle 30, and a second gas flow path G2 is formed between the inner nozzle 30 and the outer nozzle 31. With this configuration, during welding, the first inert gas flowing through the first gas flow path G1 and ejected from the tip of the inner nozzle 30 functions as a plasma gas, and the second inert gas flowing through the second gas flow path G2 and ejected from the tip of the outer nozzle 31 functions as a shielding gas. As a result, the arc generated between the workpiece and the tip of the non-consumable electrode 25 is narrowed, and welding can be performed efficiently using a high-energy-density arc (plasma arc).

[0075] Furthermore, the tip of the non-consumable electrode 25 coincides with the tip of the inner nozzle 30 in the axial direction z, or slightly protrudes from the tip of the inner nozzle 30 to one side z1 in the axial direction. The protrusion length P1 of the tip of the non-consumable electrode 25 protruding from the tip of the inner nozzle 30 to one side z1 in the axial direction is in the range of 0 to 2 mm. With this tip position of the non-consumable electrode 25, the gap between the non-consumable electrode 25 and the inner nozzle 30 is kept approximately constant narrow in the range from the middle to near the tip in the axial direction z of the inner nozzle 30. Therefore, the first inert gas of the high-speed airflow flowing around the non-consumable electrode 25 is ejected from the opening 306 at the tip of the inner nozzle 30 with almost no decrease in flow velocity. This is advantageous in preventing the adhesion of fumes, etc., to the tip of the non-consumable electrode 25 and the tip of the inner nozzle 30. Moreover, the above-mentioned effects can be achieved by devising the shape and arrangement of the inner nozzle 30, making it possible to simplify the structure of the welding torch A1 and miniaturize the tip of the welding torch A1.

[0076] In welding torch A1, the minimum gap L1 between the non-consumable electrode 25 (electrode main part 251) and the inner nozzle 30 (nozzle main part 302) in the first gas flow path G1 is smaller than the minimum gap L2 between the inner nozzle 30 (nozzle main part 302) and the outer nozzle 31 in the second gas flow path G2. With this configuration, it is possible to efficiently increase the flow velocity of the first inert gas flowing between the non-consumable electrode 25 and the inner nozzle 30. Therefore, the adhesion of fumes and the like to the tip of the non-consumable electrode 25 and the tip of the inner nozzle 30 is appropriately prevented, and the arc (plasma arc) generated between the workpiece and the non-consumable electrode 25 is tightened, and the concentration of the arc is further increased.

[0077] Figure 11 shows a modified example of the welding torch according to the present disclosure. In the welding torch A11 shown in Figure 11, the configuration of the inner nozzle 30 and the locking member 33 differs from that of the welding torch A1 of the above embodiment.

[0078] In welding torch A11, the nozzle bulge portion 303 of the inner nozzle 30 does not have the third contact surface 303a of the above embodiment. The intermediate step portion 333 of the locking member 33 does not have a fourth contact surface 333a. The annular flat end surface of the nozzle bulge portion 303 facing one side z1 in the axial direction and the annular flat end surface of the intermediate step portion 333 facing the other side z2 in the axial direction are in contact.

[0079] In this modified welding torch A11, similar to the welding torch A1 of the above embodiment, the inner nozzle 30 (small diameter nozzle portion 301 and main nozzle portion 302) is arranged concentrically with respect to the non-consumable electrode 25. The locking member 33 is fitted over the collet body 26 (first member) and the inner nozzle 30, and locks into both the collet body 26 and the inner nozzle 30. With this configuration, some radial flexibility can be provided between the locking member 33 and the collet body 26 or the inner nozzle 30. Therefore, even if the non-consumable electrode 25 is slightly bent due to manufacturing errors, the inner nozzle 30 can be arranged concentrically with respect to the non-consumable electrode 25.

[0080] The inner nozzle 30 includes a nozzle small-diameter portion 301 that has the function of centering the electrode, and a nozzle main portion 302 that can form a first gas flow path G1 between itself and the non-consumable electrode 25. These nozzle small-diameter portion 301 and nozzle main portion 302 are made of a single part. This makes it possible to provide the electrode centering function in the inner nozzle 30 while preventing an increase in the number of parts. Therefore, in this modified welding torch A11, the structure can be simplified and miniaturized.

[0081] If the inner nozzle 30 becomes misaligned with respect to the non-consumable electrode 25, a misflow occurs in the first inert gas (plasma gas) ejected from the opening 306 at the tip of the inner nozzle 30 (nozzle main portion 302). The minimum gap L1 between the non-consumable electrode 25 (electrode main portion 251) and the inner nozzle 30 (nozzle main portion 302) that constitute the first gas flow path G1 is narrow, and if the inner nozzle 30 becomes misaligned, it is likely to cause a misflow of the first inert gas (plasma gas). However, as described above, the structure, which includes a nozzle small-diameter portion 301 that has the function of centering the electrode and a locking member 33, ensures that the inner nozzle 30 (nozzle main portion 302) is positioned concentrically with respect to the non-consumable electrode 25. This is suitable for improving welding quality.

[0082] In welding torch A11, the inner nozzle 30 includes an intermediate cylindrical portion 304. The intermediate cylindrical portion 304 is located between the nozzle small diameter portion 301 and the nozzle bulge portion 303 in the axial direction z, and is connected to both the nozzle small diameter portion 301 and the nozzle main portion 302. The inner circumferential surface of the intermediate cylindrical portion 304 is a tapered surface that slopes so that the inner diameter dimension decreases as it moves toward the other side z2 in the axial direction. When replacing the non-consumable electrode 25, the end of the non-consumable electrode 25 on the other side z2 in the axial direction is inserted into the inner nozzle 30 from one side z1 in the axial direction toward the other side z2. At this time, the end of the non-consumable electrode 25 on the other side z2 in the axial direction is guided by the inner circumferential surface (tapered surface) of the intermediate cylindrical portion 304, making it possible to smoothly insert the non-consumable electrode 25 into the inside of the nozzle small diameter portion 301. This makes it possible to avoid problems such as damage to the inner nozzle 30, which is made of an insulating material (such as a relatively brittle ceramic material).

[0083] In welding torch A11, the end of the inner nozzle 30 on the other axial side z2 (second end) is in contact with the end of the collet body 26 on one axial side z1 (first end). This prevents the inner nozzle 30 from moving to the other axial side z2. In addition, the nozzle bulge 303 of the inner nozzle 30 is in contact with the intermediate step 333 of the locking member 33. This prevents the inner nozzle 30 from moving to the one axial side z1. With this configuration, when the female thread portion 331a of the locking member 33 (large diameter cylindrical portion 331) and the male thread portion 261a of the collet body 26 are tightened, the portion of the inner nozzle 30 on the other side z2 in the axial direction (part of the small diameter nozzle portion 301 and the nozzle bulge portion 303) is firmly held in place by compressive force acting from both sides in the axial direction z by the end portion z1 on one side z1 in the axial direction of the collet body 26 and the intermediate stepped portion 333 of the locking member 33.

[0084] In welding torch A11, the end of the collet body 26 on one axial side z1 (first end) has a first contact surface 262a. The end of the inner nozzle 30 on the other axial side z2 (second end) has a second contact surface 301a that contacts the first contact surface 262a. Both the first contact surface 262a and the second contact surface 301a are inclined such that their radial dimension increases towards the axial side z1. With this configuration, the alignment accuracy of the small-diameter nozzle portion 301 (inner nozzle 30) with respect to the non-consumable electrode 25 can be improved. In addition, welding torch A11 has the same effects and advantages as welding torch A1 of the above embodiment, within the same range of configuration as welding torch A1 of the above embodiment.

[0085] Figure 12 shows another modification of the welding torch according to the present disclosure. In welding torch A12 shown in Figure 12, the configuration of the collet body 26 and the inner nozzle 30 differs from that of welding torch A1 of the above embodiment.

[0086] In welding torch A12, the second contact surface 301a of the above embodiment is not formed on the other end z2 in the axial direction of the inner nozzle 30. Instead, the annular flat end surface of the inner nozzle 30 (small diameter nozzle portion 301) facing one side z1 in the axial direction is in contact with the annular flat end surface of the collet body 26 facing one side z1 in the axial direction.

[0087] In this modified welding torch A12, similar to the welding torch A1 of the above embodiment, the inner nozzle 30 (small diameter nozzle portion 301 and main nozzle portion 302) is arranged concentrically with respect to the non-consumable electrode 25. The locking member 33 is fitted over the collet body 26 (first member) and the inner nozzle 30, and locks into both the collet body 26 and the inner nozzle 30. With this configuration, some radial flexibility can be provided between the locking member 33 and the collet body 26 or the inner nozzle 30. Therefore, even if the non-consumable electrode 25 is slightly bent due to manufacturing errors, the inner nozzle 30 can be arranged concentrically with respect to the non-consumable electrode 25.

[0088] The inner nozzle 30 includes a nozzle small-diameter portion 301 that has the function of centering the electrode, and a nozzle main portion 302 that can form a first gas flow path G1 between itself and the non-consumable electrode 25. These nozzle small-diameter portion 301 and nozzle main portion 302 are made of a single part. This makes it possible to provide the electrode centering function in the inner nozzle 30 while preventing an increase in the number of parts. Therefore, the welding torch A12 of this modified example can be made simpler and smaller in structure.

[0089] If the inner nozzle 30 becomes misaligned with respect to the non-consumable electrode 25, a misflow occurs in the first inert gas (plasma gas) ejected from the opening 306 at the tip of the inner nozzle 30 (nozzle main portion 302). The minimum gap L1 between the non-consumable electrode 25 (electrode main portion 251) and the inner nozzle 30 (nozzle main portion 302) that constitute the first gas flow path G1 is narrow, and if the inner nozzle 30 becomes misaligned, it is likely to cause a misflow of the first inert gas (plasma gas). However, as described above, the structure, which includes a nozzle small-diameter portion 301 that has the function of centering the electrode and a locking member 33, ensures that the inner nozzle 30 (nozzle main portion 302) is positioned concentrically with respect to the non-consumable electrode 25. This is suitable for improving welding quality.

[0090] In welding torch A12, the inner nozzle 30 includes an intermediate cylindrical portion 304. The intermediate cylindrical portion 304 is located between the nozzle small diameter portion 301 and the nozzle bulge portion 303 in the axial direction z, and is connected to both the nozzle small diameter portion 301 and the nozzle main portion 302. The inner circumferential surface of the intermediate cylindrical portion 304 is a tapered surface that slopes so that the inner diameter dimension decreases as it moves toward the other side z2 in the axial direction. When replacing the non-consumable electrode 25, the end of the non-consumable electrode 25 on the other side z2 in the axial direction is inserted into the inner nozzle 30 from one side z1 in the axial direction toward the other side z2. At this time, the end of the non-consumable electrode 25 on the other side z2 in the axial direction is guided by the inner circumferential surface (tapered surface) of the intermediate cylindrical portion 304, making it possible to smoothly insert the non-consumable electrode 25 into the inside of the nozzle small diameter portion 301. This makes it possible to avoid problems such as damage to the inner nozzle 30, which is made of an insulating material (such as a relatively brittle ceramic material).

[0091] In welding torch A12, the end of the inner nozzle 30 on the other axial side z2 (second end) is in contact with the end of the collet body 26 on one axial side z1 (first end). This prevents the inner nozzle 30 from moving to the other axial side z2. In addition, the nozzle bulge 303 of the inner nozzle 30 is in contact with the intermediate step 333 of the locking member 33. This prevents the inner nozzle 30 from moving to the one axial side z1. With this configuration, when the female thread portion 331a of the locking member 33 (large diameter cylindrical portion 331) and the male thread portion 261a of the collet body 26 are tightened, the portion of the inner nozzle 30 on the other side z2 in the axial direction (part of the small diameter nozzle portion 301 and the nozzle bulge portion 303) is firmly held in place by compressive force acting from both sides in the axial direction z by the end portion z1 on one side z1 in the axial direction of the collet body 26 and the intermediate stepped portion 333 of the locking member 33.

[0092] In welding torch A11, the nozzle bulge portion 303 of the inner nozzle 30 has a third contact surface 303a located on one side z1 in the axial direction. The intermediate step portion 333 of the locking member 33 has a fourth contact surface 333a that contacts the third contact surface 303a. Each of the third contact surface 303a and the fourth contact surface 333a is inclined such that its radial dimension decreases as it approaches one side z1 in the axial direction. With this configuration, the alignment accuracy of the small-diameter nozzle portion 301 (inner nozzle 30) with respect to the non-consumable electrode 25 can be further improved. In addition, welding torch A12 has the same effects as welding torch A1 of the above embodiment within the same range of configuration as welding torch A1 of the above embodiment.

[0093] While embodiments of the present disclosure have been described above, the scope of the present disclosure is not limited to the embodiments described above, and any modifications within the scope of the matters described in each claim are all included within the scope of the present disclosure.

[0094] In the above embodiment, the locking member 33 was locked to the end of the collet body 26 on one side z1 in the axial direction by screwing the female thread portion 331a of the locking member 33 (large diameter cylindrical portion 331) with the male thread portion 261a of the collet body 26, but the configuration is not limited to this. For example, the locking member 33 may be locked to the end of the collet body 26 on one side z1 in the axial direction by press-fitting the end of the collet body 26 on one side z1.

[0095] A1, A11, A12: Welding torch, 25: Non-consumable electrode, 26: Collet body (first component), 262a: First contact surface, 30: Inner nozzle (first nozzle), 301: Small diameter nozzle section, 301a: Second contact surface, 302: Main nozzle section, 303: Nozzle bulge section, 303a: Third contact surface, 304: Intermediate cylindrical section, 31: Outer nozzle (second nozzle), 33: Locking member, 331: Large diameter cylindrical section, 332: Small diameter cylindrical section, 333: Intermediate stepped section, 333a: Fourth contact surface, z: Axial direction, z1: ​​One side in the axial direction, z2: Other side in the axial direction

Claims

1. A non-consumable electrode extending in the axial direction, A cylindrical first member positioned radially outward of the non-consumable electrode, A cylindrical first nozzle is positioned radially outward of the non-consumable electrode and on one side in the axial direction relative to the first member, A cylindrical locking member is fitted over the first member and the first nozzle and engages with both the first member and the first nozzle, The first nozzle includes a cylindrical nozzle small diameter portion that is concentrically fitted onto the non-consumable electrode, a cylindrical nozzle main portion located on one side in the axial direction relative to the nozzle small diameter portion and having a larger inner diameter than the nozzle small diameter portion, and a nozzle bulge portion that bulges radially outward from the nozzle small diameter portion. The locking member includes a large-diameter cylindrical portion fitted onto the nozzle bulge, a small-diameter cylindrical portion having a smaller inner diameter than the large-diameter cylindrical portion and fitted onto the main part of the nozzle, and an intermediate stepped portion connected to both the large-diameter cylindrical portion and the small-diameter cylindrical portion. The first nozzle is prevented from moving to the other side in the axial direction by the second end on the other side in the axial direction of the first nozzle contacting the first end on one side in the axial direction of the first member. A welding torch in which the first nozzle is prevented from moving to one side in the axial direction by the contact between the nozzle bulge and the intermediate step.

2. The first nozzle is located between the small diameter portion of the nozzle and the main portion of the nozzle in the axial direction and includes an intermediate cylindrical portion connected to both the small diameter portion of the nozzle and the main portion of the nozzle. The welding torch according to claim 1, wherein the inner circumferential surface of the intermediate cylindrical portion is inclined such that the inner diameter dimension decreases as it moves toward the other side in the axial direction.

3. The first end has a first contact surface, The second end has a second contact surface that contacts the first contact surface, The welding torch according to claim 2, wherein each of the first contact surface and the second contact surface is inclined such that its radial dimension increases toward one side in the axial direction.

4. The welding torch according to claim 2 or 3, wherein the large-diameter cylindrical portion of the locking member and the first end of the first member are connected by a screw.

5. The welding torch according to claim 4, wherein the first nozzle is made of an insulating material.

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