Welding torch

Abstract

To provide a welding torch which is suitable for inhibiting drift current of a shield gas when a flow rate of the shield gas increases.SOLUTION: A welding torch A1 includes: a cylindrical chip body 2 extending in an axis Ox direction; an orifice member 3 which is disposed at the radial outer side of the chip body 2 and forms an annular first space 34 between itself and the chip body 2; and a nozzle 4 which is disposed at the radial outer side of the orifice member 3, forms an annular second space 43 between itself and the orifice member 3, and has a tip 41 located at one side as seen in the axis Ox direction. The chip body 2 has first vent holes 24 leading to an internal space 22 of the chip body 2 and the first space 34. The orifice member 3 includes second vent holes 35 located at the other side as seen in the axis Ox direction with respect to the first vent holes 24 and leading to the first space 34 and the second space 43.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a welding torch. [Background technology]

[0002] For example, a welding torch used in consumable electrode arc welding is configured to feed a welding wire while receiving power from a power feed tip. The welding wire is passed through a wire insertion hole of the power feed tip and receives power by contacting the inner surface of the wire insertion hole. A welding torch is described in, for example, Patent Document 1.

[0003] As shown in Patent Document 1, the welding torch includes a torch body, a tip body, an insulator, an orifice member, a power feed tip, and a nozzle. All of these are cylindrical, and the tip body is attached to the tip of the torch body. An insulator is provided around the tip body, and an orifice member surrounds the tip of the tip body. A power feed tip is attached to the tip of the tip body, and a nozzle is screwed to the tip of the insulator.

[0004] The welding torch is configured to eject a shielding gas consisting of an inert gas or the like from the tip of the nozzle. In the welding torch described in Patent Document 1, a vent hole is formed in the tip body, and the vent hole communicates with the inner space of the tip body and the annular space between the orifice member and the tip body. A vent hole is also formed in the orifice member. The vent hole of the orifice member is located closer to the tip of the nozzle than the vent hole of the tip body, and communicates with the annular space between the orifice member and the tip body, and the annular space between the nozzle and the orifice member. When a shielding gas is sent to the welding torch, the shielding gas passes through the inner space of the torch body and the inner space of the tip body, and then passes through the vent hole of the tip body, the inner space of the orifice member, and the vent hole of the orifice member in order, and is sent to the inner space of the nozzle, and is ejected from the tip of the nozzle.

[0005] In recent years, for example, in laser-arc hybrid welding, high-speed welding is required. When welding at high speed, the flow rate of the shielding gas is increased to ensure the necessary gas shielding. In the welding torch described in the above Patent Document 1, when the flow rate of the shielding gas is increased, the shielding gas is likely to leak into the inner space of the nozzle from between the tip body and the orifice member near the tip of the orifice member, and the shielding gas is likely to drift. In addition, in the above conventional welding torch, the length from the ventilation hole of the orifice member to the tip of the nozzle is relatively short. Therefore, when the gas flow rate is increased, the shielding gas flowing in the inner space of the nozzle is ejected from the tip of the nozzle while remaining in a drift state, which hinders the improvement of the gas shielding during welding. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-213359 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been devised under these circumstances, and its main object is to provide a welding torch suitable for suppressing uneven flow of shielding gas when the flow rate of shielding gas is increased. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following technical means.

[0009] The welding torch provided by the present invention comprises a cylindrical tip body extending in the axial direction, an orifice member arranged radially outside the tip body and forming a first annular space between the tip body and the orifice member, and a nozzle arranged radially outside the orifice member and forming a second annular space between the tip body and the orifice member, the nozzle having a tip located on one side in the axial direction, wherein the tip body has a first air hole communicating with the inner space of the tip body and the first space, and the orifice member has a second air hole located on the other side in the axial direction of the first communicating hole and communicating with the first space and the second space.

[0010] In a preferred embodiment, the nozzle further comprises a seal means located on one side of the first vent hole in the axial direction and sealing the first space between the tip body and the orifice member.

[0011] In a preferred embodiment, the sealing means includes a first threaded portion formed on an outer periphery of the tip body, and a second threaded portion formed on an inner periphery of the orifice member and screwed into the first threaded portion.

[0012] In a preferred embodiment, the orifice member has an orifice tip located on one side in the axial direction, the orifice tip including a tapered outer peripheral surface having an outer diameter dimension decreasing toward one side in the axial direction, and the sealing means overlaps with the tapered outer peripheral surface when viewed in the axial direction.

[0013] In a preferred embodiment, the orifice member is made of an insulating material, the orifice member has an orifice base end located on the other side of the axial direction, the tip body has a flange portion that protrudes radially outward more than other portions, the nozzle has a nozzle base end located on the other side of the axial direction, and the orifice base end is sandwiched between the flange portion and the nozzle base end in the axial direction.

[0014] In a preferred embodiment, a nut member is provided that is threadedly connected to the outer periphery of the nozzle base end and abuts against an end face facing the other side in the axial direction at the orifice base end, and has an insulating portion interposed radially between the flange portion and the nut member. Effect of the Invention

[0015] According to the welding torch of the present invention, the shielding gas flowing in the inner space of the tip body toward the tip side of the nozzle (one side in the axial direction) flows in the first space after passing through the first vent hole of the tip body toward the other side in the axial direction so as to move away from the tip of the nozzle. After that, the shielding gas passes through the second vent hole of the orifice member, and flows toward the tip side of the nozzle (one side in the axial direction) in the second space. Therefore, the flow of the shielding gas is reversed in the first space, and the length of the gas flow path to the tip of the nozzle in the second space after passing through the second vent hole of the orifice member is ensured to be long. As a result, even when the gas flow rate of the shielding gas is increased to accommodate high-speed welding, for example, the long gas flow path inside the nozzle (second space) suppresses the drift of the shielding gas flowing in the second space, and as a result, the gas shielding performance during welding is improved.

[0016] Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0017] [Figure 1] 1 is a longitudinal sectional view showing a main portion of an embodiment of a welding torch according to the present invention. [Diagram 2] FIG. 2 is an enlarged cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 2 is an enlarged cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 2 is an enlarged cross-sectional view taken along line IV-IV in FIG. [Diagram 5] 1. FIG. 4 is a longitudinal sectional view showing a main portion of a first modified example of the welding torch shown in FIG. [Figure 6]1. FIG. 4 is a longitudinal sectional view showing a main portion of a second modified example of the welding torch shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0019] 1 shows an embodiment of a welding torch according to the present invention. The welding torch A1 of this embodiment includes a torch body 1, a tip body 2, an orifice member 3, a nozzle 4, a nut member 5, an insulating ring 6, a power feed tip 7, and a guide liner 8.

[0020] The torch body 1 is cylindrical and extends along an axis Ox. The torch body 1 has a cylindrical inner circumferential surface 11, and the area surrounded by this inner circumferential surface 11 corresponds to an inner space 12 of the torch body 1. The torch body 1 is made of a conductive metal material.

[0021] The tip body 2 is cylindrical and is attached to the tip of the torch body 1. The tip body 2 extends in the direction of the axis Ox (the direction along the axis Ox) and has a cylindrical inner peripheral surface 21. The area surrounded by the inner peripheral surface 21 corresponds to the inner space 22 of the tip body 2. The tip body 2 is attached to the tip of the torch body 1 by a screw means 23. The tip body 2 is made of a conductive metal material and receives a welding current from the torch body 1. In the example shown in FIG. 1, the inner diameter of the inner peripheral surface 21 of the tip body 2 is approximately the same as the inner diameter of the inner peripheral surface 11 of the torch body 1. The inner diameter of the inner peripheral surface 21 and the inner diameter of the inner peripheral surface 11 may be different.

[0022] The chip body 2 has a first vent hole 24, a flange portion 25, and a first screw portion 26. The first vent hole 24 penetrates the chip body 2 in the thickness direction (radial direction). In this embodiment, as shown in FIG. 1, FIG. 3, and FIG. 4, the chip body 2 has a plurality of first vent holes 24. The plurality of first vent holes 24 are located at the middle of the chip body 2 in the axis Ox direction, and are formed at regular angles in the circumferential direction of the chip body 2. In the illustrated example, the plurality of first vent holes 24 include a plurality of first vent holes 241 and a plurality of first vent holes 242. As shown in FIG. 3, the plurality of first vent holes 241 are arranged at 90° intervals in the circumferential direction of the chip body 2. As shown in FIG. 4, the plurality of first vent holes 242 are arranged at 90° intervals in the circumferential direction of the chip body 2. The plurality of first vent holes 241 and the plurality of first vent holes 242 are arranged at small intervals in the axis Ox direction. The multiple first air vents 241 are located closer to the tip end of the tip body 2 (one side in the direction of the axis Ox, the lower side in FIG. 1) than the multiple first air vents 242. The multiple first air vents 241 and the multiple first air vents 242 are positioned at 45° offset from each other in the circumferential direction of the tip body 2. With this configuration, the multiple first air vents 241 and the multiple first air vents 242 do not overlap each other when viewed in the direction of the axis Ox.

[0023] As shown in Fig. 1, the flange portion 25 is a portion that protrudes radially outward further than other portions of the tip body 2. The flange portion 25 is located on the other side in the direction of the axis Ox (upper side in Fig. 1) of the first air hole 24. The first threaded portion 26 is formed on the outer periphery of the tip body 2. The first threaded portion 26 is located closer to the tip of the nozzle 4 than the first air hole 24 (on one side in the direction of the axis Ox).

[0024] The orifice member 3 is cylindrical and disposed radially outward of the tip body 2. The orifice member 3 extends in the direction of the axis Ox. The orifice member 3 has an orifice tip portion 31, an orifice base portion 32, and an annular groove 33.

[0025] The orifice tip portion 31 is a portion of the orifice member 3 located on one side in the direction of the axis Ox (the lower side in FIG. 1). The orifice tip portion 31 is fitted onto the tip body 2 with almost no gap between the tip body 2 and the orifice tip portion 31. The orifice tip portion 31 includes a tapered outer peripheral surface 311. The outer diameter dimension of the tapered outer peripheral surface 311 decreases toward one side in the direction of the axis Ox.

[0026] The orifice base end 32 is a portion of the orifice member 3 located on the other side in the direction of the axis Ox (the upper side in FIG. 1). In this embodiment, the orifice base end 32 includes a portion that protrudes radially outward in an annular shape. The orifice base end 32 has an end face 321 facing the other side in the direction of the axis Ox.

[0027] The annular groove 33 is located on the other side in the direction of the axis Ox (closer to the orifice base end 32) than the orifice tip portion 31, and has an inner diameter dimension larger than the inner diameter dimension of the orifice tip portion 31. In this embodiment, an annular first space 34 is formed between the outer circumferential surface of the tip body 2 and the inner circumferential surface of the annular groove 33. As shown in FIGS. 1, 3, and 4, all of the multiple first vent holes 24 (multiple first vent holes 241 and multiple first vent holes 242) of the tip body 2 communicate with both the inner space 22 of the tip body 2 and the first space 34.

[0028] As shown in FIG. 1, the orifice member 3 has a second vent hole 35 and a first screw portion 26. The second vent hole 35 penetrates the orifice member 3 in the thickness direction (radial direction). In this embodiment, as shown in FIG. 1 and FIG. 2, the orifice member 3 has a plurality of second vent holes 35. The plurality of second vent holes 35 are located on the other side in the axis Ox direction (upper side in FIG. 1) with respect to the plurality of first vent holes 24 of the tip body 2. The plurality of second vent holes 35 are formed at regular angles in the circumferential direction of the orifice member 3 (see FIG. 2). In the illustrated example, the plurality of second vent holes 35 are arranged at 45° intervals in the circumferential direction of the orifice member 3.

[0029] The second threaded portion 36 is formed on the inner circumference of the orifice member 3. The second threaded portion 36 is located closer to the tip of the nozzle 4 (on one side in the direction of the axis Ox) than the first air hole 24 of the tip body 2. The second threaded portion 36 screws into the first threaded portion 26 of the tip body 2. The first threaded portion 26 and the second threaded portion 36 overlap with the tapered outer peripheral surface 311 of the orifice member 3 when viewed in the direction of the axis Ox. The orifice member 3 configured as described above is made of an insulating material such as resin or ceramics.

[0030] The nozzle 4 is cylindrical and disposed radially outward of the orifice member 3. The nozzle 4 extends in the direction of the axis Ox. A tip 41 of the nozzle 4 (one end in the direction of the axis Ox, the lower end of the nozzle 4 in FIG. 1) is open to the outside. The nozzle 4 is made of a conductive metal material.

[0031] The nozzle 4 has a nozzle base end 42. The nozzle base end 42 is a portion of the nozzle 4 that is located on the other side in the direction of the axis Ox (the upper side in FIG. 1). In this embodiment, the nozzle base end 42 protrudes in an annular shape radially outward further than other portions.

[0032] In this embodiment, an annular second space 43 is formed between the outer circumferential surface of the orifice member 3 and the inner circumferential surface of the nozzle 4. As shown in Figures 1 and 2, each of the multiple second air holes 35 of the orifice member 3 communicates with both the first space 34 and the second space 43.

[0033] The nut member 5 is fitted onto the nozzle base end 42. In this embodiment, the nut member 5 is attached to the outer periphery of the nozzle base end 42 by a screw means 51. In this embodiment, the nut member 5 is a member for assembling the nozzle 4 to the welding torch A1. In this embodiment, it abuts against the end face 321 of the orifice base end 32 in the orifice member 3. By tightening the nut member 5, the nozzle 4 is drawn to the other side in the direction of the axis Ox (upper side in FIG. 1). In this way, as shown in FIG. 1, the orifice base end 32 is sandwiched between the flange portion 25 of the tip body 2 and the nozzle base end 42 in the direction of the axis Ox.

[0034] The insulating ring 6 is an annular member made of an insulating material. In this embodiment, the insulating ring 6 abuts against the end face 321 of the orifice base end portion 32, and is interposed radially between the flange portion 25 of the tip body 2 and the nut member 5. The insulating ring 6 corresponds to an example of an insulating portion of the present invention.

[0035] The power feed tip 7 is attached to the tip (one end in the direction of the axis Ox) of the tip body 2. The power feed tip 7 has a base end (the other end in the direction of the axis Ox) attached to the tip of the tip body 2 by a screw means 71. A wire insertion hole 72 for passing a welding wire is formed through the power feed tip 7 from the base end to the tip. At the base end of the power feed tip 7, the wire insertion hole 72 is tapered, and the welding wire (not shown) fed to the welding torch A1 is fed to the tip side of the power feed tip 7 while being centered and guided by the tapered portion.

[0036] The guide liner 8 is disposed in the inner space 22 of the torch body 1 and the inner space 22 of the tip body 2. The guide liner 8 is tubular and flexible, and serves to guide the welding wire (not shown) by inserting the welding wire through the guide liner 8. A synthetic resin material that has a small sliding resistance for the welding wire is suitable as a material for the guide liner 8. The guide liner 8 extends close to the power feed tip 7. The welding wire (not shown) fed to the welding torch A1 is guided through the inside of the guide liner 8 in the inner space 12 of the torch body 1 and the inner space 22 of the tip body 2, passes through the wire insertion hole 72 of the power feed tip 7, and is led out from the tip of the power feed tip 7. Instead of the guide liner 8, a coil liner formed by winding a metal wire in a spiral shape may be used.

[0037] The welding torch A1 is configured to eject a shielding gas consisting of an inert gas or the like from the tip 41 of the nozzle 4. When the shielding gas is sent to the welding torch A1, the shielding gas passes through the inner space 12 of the torch body 1 and the inner space 22 of the tip body 2, and then passes through the first vent holes 24 (the first vent holes 241 and the first vent holes 242) of the tip body 2, the first space 34 of the orifice member 3, and the second vent holes 35 of the orifice member 3, and is sent to the second space 43 of the nozzle 4, and is ejected from the tip 41 of the nozzle 4. The inner space 12 of the torch body 1, the inner space 22 of the tip body 2, the first vent hole 24 of the tip body 2, the first space 34, the second vent hole 35 of the orifice member 3, and the second space 43 each serve as a gas flow path through which the shielding gas flows. In FIG. 1, the flow of the shielding gas is indicated by arrows.

[0038] Next, the operation of this embodiment will be described.

[0039] In this embodiment, the tip body 2 has a first vent hole 24. The first vent hole 24 communicates with the inner space 22 of the tip body 2 and the annular first space 34 between the tip body 2 and the orifice member 3. The orifice member 3 has a second vent hole 35. The second vent hole 35 is located on the other side of the axis Ox direction with respect to the first vent hole 24. The second vent hole 35 communicates with the first space 34 between the tip body 2 and the orifice member 3 and the annular second space 43 between the orifice member 3 and the nozzle 4. The tip 41 of the nozzle 4 is located on one side of the axis Ox direction. According to this configuration, the shielding gas flowing through the inner space 22 of the tip body 2 toward the tip 41 side of the nozzle 4 (one side of the axis Ox direction) flows to the other side of the axis Ox direction so as to move away from the tip 41 of the nozzle 4 in the first space 34 after passing through the first vent hole 24 of the tip body 2. Thereafter, the shielding gas passes through the second vent hole 35 of the orifice member 3 and flows toward the tip 41 of the nozzle 4 in the second space 43 (one side in the direction of the axis Ox). Therefore, the flow of the shielding gas is reversed in the first space 34, and the length of the gas flow path to the tip 41 of the nozzle 4 in the second space 43 after passing through the second vent hole 35 of the orifice member 3 is ensured to be long. As a result, even when the gas flow rate of the shielding gas is increased to accommodate high-speed welding in the welding torch A1, the long gas flow path inside the nozzle 4 (second space 43) suppresses the uneven flow of the shielding gas flowing in the second space 43, and as a result, the gas shielding property during welding is improved. Note that, as in this embodiment, the configuration in which the tip body 2 is provided with a plurality of first vent holes 24 and the configuration in which the orifice member 3 is provided with a plurality of second vent holes 35 are suitable for suppressing the uneven flow of the shielding gas flowing in the first space 34 and the second space 43.

[0040] The tip body 2 has a first screw portion 26 located on one side of the first vent hole 24 in the direction of the axis Ox. The orifice member 3 has a second screw portion 36, which is screwed into the first screw portion 26. With this configuration, the first screw portion 26 and the second screw portion 36 close the first space 34 between the tip body 2 and the orifice member 3. Therefore, even if the gas pressure in the first space 34 increases by increasing the gas flow rate of the shielding gas, leakage of the shielding gas from the gap between the tip body 2 and the orifice member 3 is prevented, and the uneven flow of the shielding gas can be appropriately suppressed. The first screw portion 26 of the tip body 2 and the second screw portion 36 of the orifice member 3 correspond to an example of a sealing means of the present invention.

[0041] The orifice member 3 has an orifice tip 31 located on one side in the direction of the axis Ox. The orifice tip 31 has a tapered outer peripheral surface 311, and the outer diameter dimension of the tapered outer peripheral surface 311 decreases toward one side of the axis Ox. The first screw portion 26 of the tip body 2 and the second screw portion 36 of the orifice member 3 overlap with the tapered outer peripheral surface 311 when viewed in the direction of the axis Ox. With this configuration, the tapered outer peripheral surface 311 can be made a gentle inclined surface with a relatively long length in the direction of the axis Ox. As a result, it is possible to efficiently suppress the drift of the shielding gas after passing through the fitting portion (the first screw portion 26 and the second screw portion 36) between the tip body 2 and the orifice member 3 inside the nozzle 4 (the second space 43) of the shielding gas flow path.

[0042] The orifice member 3 is made of an insulating material and has an orifice base end 32. The orifice base end 32 is located on the other side of the axis Ox direction in the orifice member 3 (upper side in FIG. 1). The orifice base end 32 is sandwiched between the flange portion 25 of the tip body 2 and the nozzle base end 42 in the axis Ox direction. With this configuration, the orifice base end 32 extends long toward the other side in the axis Ox direction to a position corresponding to the nozzle base end 42, and the orifice member 3 has a function of electrically insulating the tip body 2 and the nozzle 4. According to this embodiment, a separate insulator that has been provided to insulate the tip body and the nozzle in the conventional art is not necessary, so that the overall structure of the welding torch A1 can be simplified.

[0043] The welding torch A1 of this embodiment includes a nut member 5 and an insulating ring 6. The nut member 5 is screwed to the outer periphery of the nozzle base end 42 and abuts against the end face 321 (the face facing the other side in the direction of the axis Ox) of the orifice base end 32. The insulating ring 6 is interposed between the flange 25 of the tip body 2 and the nut member 5 in the radial direction. With this configuration, the nozzle 4 can be easily assembled to the welding torch A1 by using the nut member 5. In addition, the insulating ring 6 is interposed between the flange 25 of the tip body 2 and the nut member 5, so that the tip body 2 and the nozzle 4 can be more reliably insulated from each other.

[0044] Fig. 5 shows a first modified example of the welding torch according to the embodiment. In Fig. 5 and subsequent figures, elements that are the same as or similar to those in the first embodiment are given the same reference numerals as those in the first embodiment, and descriptions thereof will be omitted as appropriate.

[0045] In the welding torch A2 shown in FIG. 5, an O-ring groove 27 is formed on the outer periphery of the tip body 2, and an O-ring 28 is accommodated in the O-ring groove 27. The O-ring groove 27 is located closer to the tip of the nozzle 4 than the first vent hole 24 (on one side in the direction of the axis Ox). The O-ring 28 attached to the tip body 2 in this manner blocks the first space 34 between the tip body 2 and the orifice member 3. Therefore, even if the gas pressure in the first space 34 increases by increasing the gas flow rate of the shielding gas, leakage of the shielding gas from the gap between the tip body 2 and the orifice member 3 is appropriately prevented, and the uneven flow of the shielding gas can be appropriately suppressed. The O-ring groove 27 in the tip body 2 and the O-ring 28 accommodated in the O-ring groove 27 correspond to an example of the sealing means of the present invention.

[0046] FIG. 6 shows a second modified example of the welding torch according to the embodiment. Unlike the welding torch A1 of the embodiment, the welding torch A3 shown in FIG. 6 does not include an insulating ring 6. On the other hand, the orifice base end 32 of the orifice member 3 has an extension 322. The extension 322 extends to the other side in the axis Ox direction from other parts of the orifice base end 32 and is annular. As shown in FIG. 6, the extension 322 is interposed between the flange 25 of the tip body 2 and the nut member 5 in the radial direction. According to this configuration, the extension 322 is interposed between the flange 25 of the tip body 2 and the nut member 5, so that the tip body 2 and the nozzle 4 can be more reliably insulated from each other. The extension 322 in the orifice member 3 corresponds to an example of an insulating part of the present invention.

[0047] Although an embodiment of the present invention has been described above, the scope of the present invention is not limited to the above-described embodiment, and all modifications within the scope of the matters described in each claim are included in the scope of the present invention. [Explanation of symbols]

[0048] A1, A2, A3: welding torch, 2: tip body, 22: inner space, 24, 241, 242: first vent hole, 25: flange, 26: first screw portion (sealing means), 27: O-ring groove (sealing means), 28: O-ring (sealing means), 3: orifice member, 31: orifice tip, 311: tapered outer circumferential surface, 32: orifice base end, 321: end face, 322: extension (insulating portion), 34: first space, 35: second vent hole, 36: second screw portion (sealing means), 4: nozzle, 41: tip, 42: nozzle base end, 43: second space, 5: nut member, 51: screw means, 6: insulating ring (insulating portion), Ox: axis

Claims

1. A cylindrical tip body extending in an axial direction; an orifice member disposed radially outward of the tip body and defining an annular first space between the tip body and the orifice member; a nozzle disposed radially outward of the orifice member, with a second annular space formed between the nozzle and the orifice member, and having a tip located on one side in the axial direction; the tip body has a first vent hole communicating with an inner space of the tip body and the first space; The orifice member is located on the other side of the first vent hole in the axial direction and has a second vent hole communicating with the first space and the second space.

2. 2. The welding torch according to claim 1, further comprising a seal means located on one side of the first vent hole in the axial direction and sealing the first space between the tip body and the orifice member.

3. The orifice member has an orifice tip portion located on one side in the axial direction, the orifice tip portion includes a tapered outer circumferential surface having an outer diameter dimension that decreases toward one side in the axial direction, 3. The welding torch of claim 2, wherein said sealing means overlaps said tapered outer peripheral surface when viewed in said axial direction.

4. The orifice member is made of an insulating material, the orifice member has an orifice base end portion located on the other side in the axial direction, The tip body has a flange portion that protrudes radially outward beyond other portions, the nozzle has a nozzle base end located on the other side in the axial direction, 4. The welding torch according to claim 1, wherein the orifice base end portion is sandwiched between the flange portion and the nozzle base end portion in the axial direction.

5. a nut member that is screwed onto an outer periphery of the nozzle base end portion and abuts against an end surface of the orifice base end portion that faces the other side in the axial direction; The welding torch according to claim 4 , further comprising an insulating portion interposed between the flange portion and the nut member in the radial direction.

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