welding torch

Abstract

To provide a welding torch suitable for achieving down-sizing and structure simplification.SOLUTION: A welding torch A1 comprises: an electrode 25 extending in an axial direction z; an inner nozzle 30 located outside an end of the electrode 25 on axial direction one side z1; an outer nozzle 31 located outside the inner nozzle 30; and a torch body 2 located on axial direction other side z2 of the inner nozzle 30. A first gas passage G1 is formed between the electrode 25 and the inner nozzle 30, and a second gas passage G2 is formed between the inner nozzle 30 and the outer nozzle 31. The torch body 2 has a first gas inflow port 211 communicating with the first gas passage G1, and a second gas inflow port 212 communicating with the second gas passage G2. The first gas inflow port 211 is positioned on axial direction other side z2 of the second gas inflow port 212. The first gas inflow port 211 is inclined so as to be positioned on axial direction one side z1 as approaching the electrode 25 in a first direction x orthogonal to the axial direction z.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention 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), usually, an arc is 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 a 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, whereby the arc (plasma arc) is confined. 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 an 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. The 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). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2009-172644 [Overview of the project] [Problems that the invention aims to solve]

[0006] This invention was conceived under these circumstances, and its main objective is to provide a welding torch suitable for miniaturization and simplification of structure. [Means for solving the problem]

[0007] To solve the above problems, the present invention employs the following technical means.

[0008] A welding torch provided by the present invention comprises a non-consumable electrode extending in the axial direction, an inner nozzle positioned radially outward at one end of the non-consumable electrode in the axial direction, an outer nozzle positioned radially outward with respect to the inner nozzle, and a torch body positioned on the other side in the axial direction with respect to the inner nozzle, wherein a first gas flow path is formed between the non-consumable electrode and the inner nozzle, and a second gas flow path is formed between the inner nozzle and the outer nozzle, and the torch body has a first gas inlet leading to the first gas flow path and a second gas inlet leading to the second gas flow path, wherein the first gas inlet is positioned on the other side in the axial direction with respect to the second gas inlet, and the first gas inlet is inclined to be positioned on one side in the axial direction as it approaches the non-consumable electrode in a first direction perpendicular to the axial direction.

[0009] In a preferred embodiment, the second gas inlet is inclined to be located on one side of the axial direction as it approaches the non-consumable electrode in the first direction.

[0010] In a preferred embodiment, the torch body further comprises a threaded member that screws into the female threaded portion, which has a female threaded portion adjacent to the other side in the axial direction with respect to the first gas inlet.

[0011] In a preferred embodiment, the torch body has a cooling water channel located between the first gas inlet and the second gas inlet in the axial direction and formed along the circumferential direction of the non-consumable electrode.

[0012] In a preferred embodiment, the torch body includes a first cylindrical portion extending along the axial direction and a second cylindrical portion connected to the first cylindrical portion and extending in a direction intersecting the axial direction, wherein the first cylindrical portion is arranged to straddle the first gas inlet and the second gas inlet in the axial direction, and further comprises a first gas pipe and a second gas pipe, each inserted through the interior of the second cylindrical portion and leading to the first gas inlet. [Effects of the Invention]

[0013] According to the welding torch of the present invention, the opening end of the first gas inlet provided on the torch body can be brought closer to the inner nozzle side (one side in the axial direction) in the axial direction. This makes it possible to reduce the axial dimensions of the torch body and to miniaturize the welding torch.

[0014] Other features and advantages of the present invention will become more apparent from the detailed description below with reference to the accompanying drawings. [Brief explanation of the drawing]

[0015] [Figure 1] This is a front view showing an example of a welding torch according to the present invention. [Figure 2] Figure 1 is a plan view of the welding torch. [Figure 3] This is a cross-sectional view along line III-III in Figure 2. [Figure 4] This is a cross-sectional view along the line IV-IV in Figure 3. [Figure 5] This is an enlarged cross-sectional view along the VV line in Figure 3. [Figure 6] This is an enlarged cross-sectional view along the line VI-VI in Figure 3. [Figure 7] This is an enlarged cross-sectional view along the line VII-VII in Figure 3. [Figure 8] This is a magnified view of a portion of Figure 3. [Modes for carrying out the invention]

[0016] Hereinafter, preferred embodiments of the present invention 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.

[0017] Figs. 1 to 8 show an example of a welding torch according to the present invention. The welding torch A1 of this 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, an electrode centering member 34, 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 this embodiment is configured to be held by an operator's hand to perform welding work. Also, 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.

[0018] 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 invention and is referred to as the "axial direction z". The direction orthogonal to the axial direction z in Figs. 3 and 8 (the left-right direction in the drawings) is an example of the "first direction" of the present invention and is referred to as the "first direction x". Also, 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 invention 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 invention and is referred to as the "other side of the axial direction z2".

[0019] The handle 1 is a part for an operator to hold by hand. As shown in Fig. 3, the handle 1 is a cylindrical member made of an insulating material. The handle 1 is a part for an operator to hold by hand. As shown in Fig. 3, the handle 1 is a cylindrical member made of an insulating material.

[0020] 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.

[0021] 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.

[0022] 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 Figure 8, the cylindrical member 21 has a first gas inlet 211, a second gas inlet 212, a groove 213, a tapered surface 214, and a female threaded portion 215. 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.

[0023] 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.

[0024] 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.

[0025] 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 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 1.0 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.

[0026] 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.

[0027] The collet 27 surrounds the non-consumable electrode 25. The collet body 26 is positioned radially outward of the collet 27. The collet body 26 is also positioned radially inward of the cylindrical member 21. Although detailed illustrations are omitted, the collet body 26 is fixed to the cylindrical member 21, for example, by a screw connection.

[0028] 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 threaded portion that is screwed into the cylindrical member 21. As shown in Figure 8, a female threaded portion 215 is formed at the upper end of the cylindrical member 21 (the end on the other axial side z2), and the threaded portion of the collet retaining member 28 is screwed into the female threaded portion 215. 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.

[0029] 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.

[0030] 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 substantially cylindrical and is positioned radially outward of the non-consumable electrode 25 (electrode main portion 251). In this embodiment, an electrode centering member 34 is interposed between the inner nozzle 30 and the non-consumable electrode 25.

[0031] The locking member 33 is fitted over both the collet body 26 and the inner nozzle 30. More specifically, the locking member 33 is fitted over one axial end z1 of the collet body 26 and the other axial end z2 of the inner nozzle 30. In the illustrated example, the locking member 33 has a cap nut structure.

[0032] In this embodiment, as shown in Figure 3, the locking member 33 and the end of the collet body 26 on one side z1 in the axial direction are connected by a screw. For example, a male threaded portion 261 is formed on the outer circumference of the end of the collet body 26 on one side z1 in the axial direction, and a female threaded portion 331 formed on the locking member 33 is screwed into the male threaded portion 261 of the collet body 26. On the other hand, the portion of the locking member 33 on one side z1 in the axial direction is fitted onto the inner nozzle 30, and the locking member 33 is locked by the large diameter portion of the outer circumference on the other side z2 in the axial direction of the inner nozzle 30. As a result, relative movement of the inner nozzle 30 and the locking member 33 in the axial direction z is restricted.

[0033] The electrode centering member 34 is generally cylindrical and is positioned radially outside the non-consumable electrode 25 and radially inside the inner nozzle 30. A tapered recess is formed on the inner circumference of the inner nozzle 30 on the other axial side z2, and a tapered protrusion of the electrode centering member 34 fits into this tapered recess. The inner diameter of the electrode centering member 34 is slightly larger than the outer diameter of the non-consumable electrode 25 (electrode main portion 251). As a result, the electrode centering member 34 is concentrically fitted to the non-consumable electrode 25. Furthermore, the tapered protrusion of the electrode centering member 34 fits into the tapered recess of the inner nozzle 30. As a result, the inner nozzle 30 is concentrically fitted to the electrode centering member 34. Therefore, the inner nozzle 30 is concentrically positioned with respect to the non-consumable electrode 25 via the electrode centering member 34. As shown in Figure 7, a plurality of grooves 341 are formed on the inner circumference of the electrode centering member 34. These grooves 341 are provided at regular intervals in the circumferential direction of the electrode centering member 34. A gap is formed between the non-consumable electrode 25 and the portion where the grooves 341 are formed, and this gap constitutes the first gas flow path G1, which will be described later.

[0034] 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 of the tip of the non-consumable electrode 25 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.

[0035] The nozzle holder 32 is cylindrical in shape. The nozzle holder 32 is integrally connected to the outer circumference of the intermediate portion in the axial direction z of the collet body 26 by means of, for example, brazing.

[0036] As shown in Figure 3, 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.

[0037] As shown in Figure 3, 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 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.

[0038] 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.

[0039] 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."

[0040] The first gas flow path G1 is a flow path for the first inert gas. In Figure 3, 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, between the non-consumable electrode 25 (electrode main part 251) and the electrode centering member 34, and between the non-consumable electrode 25 (electrode main part 251) and the inner nozzle 30.

[0041] In this embodiment, as shown in Figures 3 and 8, 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 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 at the tip of the inner nozzle 30.

[0042] The second gas flow path G2 is a flow path for the second inert gas. In Figure 3, the flow of the second inert gas is indicated by a dotted arrow. 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.

[0043] In this embodiment, as shown in Figures 3 and 8, 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 at the tip of the outer nozzle 31.

[0044] 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.

[0045] Referring to Figure 8 and other figures, the first gas inlet 211, second gas inlet 212, groove 213, tapered surface 214, and female thread portion 215 of the cylindrical member 21 will be described. As shown in Figure 8, 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.

[0046] 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.

[0047] The tapered surface 214 is located at the open end of the second gas inlet 212. The tapered surface 214 is inclined so as it approaches the non-consumable electrode 25, it is located on the other side z2 in the axial direction. In the cross-section shown in Figure 8, the angle between the tapered surface 214 and the second gas inlet 212 is approximately a right angle.

[0048] The groove 213 is a portion of the outer circumferential 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 Figures 4 and 8, 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. Also, in this embodiment, as shown in Figure 8, the cooling water flow path W is located between the first gas inlet 211 and the cylindrical member 22 in the axial direction z.

[0049] As shown in Figure 8, the female threaded portion 215 is adjacent to the first gas inlet 211 on the other axial side z2. The threaded portion of the collet retaining member 28 is screwed into this female threaded portion 215 as described above. The collet retaining member 28 having this threaded portion corresponds to an example of the "threaded member" of the present invention.

[0050] As shown in Figures 3 and 8, 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.

[0051] 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.

[0052] 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.

[0053] Next, the operation of this embodiment will be described.

[0054] The welding torch A1 of this embodiment includes a non-consumable electrode 25 extending in the axial direction z, an inner nozzle 30, and an outer nozzle 31. The inner nozzle 30 is arranged concentrically on the radially outer side of the non-consumable electrode 25, and a first gas flow path G1 is formed between the non-consumable electrode 25 and the inner nozzle 30. The outer nozzle 31 is arranged radially outer 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).

[0055] The torch body 2 is positioned on the other side z2 in the axial direction relative to the inner nozzle 30. The torch body 2 (cylindrical member 21) has a first gas inlet 211 that leads to a first gas passage G1 and a second gas inlet 212 that leads to a second gas passage G2. 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 so that as it approaches the non-consumable electrode 25 in a first direction x perpendicular to the axial direction z, it is positioned on one side z1 in the axial direction. With this configuration, it is possible to bring the open end of the first gas inlet 211 provided on the torch body 2 (cylindrical member 21) closer to the inner nozzle 30 side (one side z1 in the axial direction) in the axial direction z. This makes it possible to reduce the axial dimension z of the torch body 2 (first cylindrical part 20A), and thus make the welding torch A1 smaller. The welding torch A1 in this embodiment is a handheld type that is held by the operator to perform welding work. The miniaturization of the welding torch A1 contributes to reducing the burden on the operator and is expected to improve welding performance.

[0056] In this embodiment, the second gas inlet 212 is inclined to be located on one side z1 in the axial direction as it approaches the non-consumable electrode 25 in the first direction x. With this configuration, by making the portion where the open end of the second gas inlet 212 is located a tapered surface 214, for example, the peripheral portion of the cylindrical member 21 (torch body 2) around the second gas inlet 212 can be miniaturized.

[0057] The cylindrical member 21 (torch body 2) has a female threaded portion 215. The female threaded portion 215 is adjacent to the first gas inlet 211 on the other side z2 in the axial direction. The welding torch A1 is equipped with a collet retaining member 28 (threaded member) that screws into the female threaded portion 215. With this configuration, the mounting position of the collet retaining member 28 can be shifted to the other side z2 in the axial direction while ensuring the length of the female threaded portion 215 in the axial direction z. Furthermore, it is possible to avoid the second gas inlet 212 being blocked by the collet retaining member 28 that screws into the female threaded portion 215. Such a structure is more preferable for miniaturizing the welding torch A1.

[0058] The torch body 2 has a cooling water channel W. The cooling water channel W is located between the first gas inlet 211 and the cylindrical member 22 in the axial direction z, and is formed along the circumferential direction of the non-consumable electrode 25. With this configuration, the welding torch A1 can be miniaturized while also providing a cooling function to the welding torch A1.

[0059] The torch body 2 includes a first cylindrical portion 20A and a second cylindrical portion 20B connected to the first cylindrical portion 20A. The first cylindrical portion 20A extends along the axial direction z, and the second cylindrical portion 20B extends in a direction intersecting the axial direction z. The first cylindrical portion 20A is positioned to straddle the first gas inlet 211 and the second gas inlet 212 in the axial direction z. A first gas pipe 41 and a second gas pipe 42 are provided, passing through the interior of the second cylindrical portion 20B. The first gas pipe 41 is connected to the first gas inlet 211, and the second gas pipe 42 is connected to the second gas inlet 212. With this configuration, different gases (for example, the first inert gas and the second inert gas described above) can be appropriately supplied to the first gas flow path G1 and the second gas flow path G2 via the first gas pipe 41 and the second gas pipe 42.

[0060] In this embodiment, the welding torch A1 includes an electrode centering member 34 and a locking member 33. The electrode centering member 34 is concentrically fitted onto the non-consumable electrode 25. The inner nozzle 30 is also concentrically fitted onto the electrode centering member 34. As a result, the inner nozzle 30 is positioned concentrically with respect to the non-consumable electrode 25 via the electrode centering member 34. The locking member 33 is fitted across one axial end z1 of the collet body 26 and the other axial end z2 of the inner nozzle 30, and locks onto 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 positioned concentrically with respect to the non-consumable electrode 25.

[0061] Furthermore, since the inner nozzle 30 is arranged concentrically on the radially outer side 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 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.

[0062] 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 of the tip of the non-consumable electrode 25 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 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 are 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.

[0063] Although embodiments of the present invention have been described above, the scope of the present invention 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 invention.

[0064] In the above embodiment of the welding torch A1, the case in which the outer nozzle 31 is arranged concentrically with respect to the inner nozzle 30 has been described, but the present invention is not limited to this. The outer nozzle 31 may be arranged radially offset with respect to the inner nozzle 30. Furthermore, the above embodiment of the welding torch A1 was an example of a hand-held specification in which an operator holds the torch by hand to perform welding work, but the present invention is not limited to this. The welding torch according to the present invention may be configured as a robot specification to be equipped on a welding robot (such as an articulated robot), for example. [Explanation of Symbols]

[0065] A1: Welding torch, 2: Torch body, 20A: First cylindrical part, 20B: Second cylindrical part, 211: First gas inlet, 212: Second gas inlet, 215: Female threaded part, 25: Non-consumable electrode, 28: Collet retaining member (threaded member), 30: Inner nozzle, 31: Outer nozzle, 41: First gas piping, 42: Second gas piping, G1: First gas flow path, G2: Second gas flow path, W: Cooling water flow path, z: Axial direction, z1: ​​One side of the axial direction, z2: The other side of the axial direction, x: First direction

Claims

1. A non-consumable electrode extending in the axial direction, An inner nozzle is positioned radially outward at one end of the non-consumable electrode in the axial direction, An outer nozzle positioned radially outward from the inner nozzle, The torch body is positioned on the other side in the axial direction relative to the inner nozzle, A first gas flow path is formed between the non-consumable electrode and the inner nozzle. A second gas flow path is formed between the inner nozzle and the outer nozzle. The torch body has a first gas inlet leading to the first gas passage and a second gas inlet leading to the second gas passage. The first gas inlet is located on the other side in the axial direction relative to the second gas inlet. The torch body has a cooling water channel located between the first gas inlet and the second gas inlet in the axial direction and formed along the circumferential direction of the non-consumable electrode, The first gas inlet and the second inlet are inclined such that they are positioned on one side of the axial direction as they approach the non-consumable electrode in a first direction perpendicular to the axial direction. The torch body has a tapered surface on which the opening end of the second gas inlet is located. A welding torch in which the tapered surface is inclined to be located on the other side in the axial direction as it approaches the non-consumable electrode.

2. The torch body has a female threaded portion adjacent to the other side in the axial direction with respect to the first gas inlet, The welding torch according to claim 1, further comprising a screw member that screws into the female screw portion.

3. The torch body includes a first cylindrical portion extending along the axial direction and a second cylindrical portion connected to the first cylindrical portion and extending in a direction intersecting the axial direction, The first cylindrical portion is positioned to straddle the first gas inlet and the second gas inlet in the axial direction, The welding torch according to claim 1 or 2, further comprising a first gas pipe, each inserted through the inside of the second cylindrical portion and leading to the first gas inlet, and a second gas pipe, each leading to the second gas inlet.

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