welding torch

Abstract

To provide a welding torch which extends a laminar flow length of a shield gas flow jetted from a nozzle tip to further improve welding quality.SOLUTION: A welding torch A1 includes: a cylindrical chip body 2 extending in an axial direction; an orifice member 3 which is disposed at a radial outer side of the chip body 2 and forms a first annular space 21 with the chip body 2; and a cylindrical nozzle 4 which is disposed at a radial outer side of the orifice member 3 through a second annular space 411 and has a tip at one side as seen in the axial direction. The chip body 2 has first jet holes 22 leading from an internal space of the chip body 2 to the first annular space 21. The orifice member 3 has second jet holes 34 leading from the first annular space 21 to the second annular space 411. The second annular space 411 is substantially closed by a closing part 36 at the other side in the axial direction. An outlet opening 341 of each second jet hole 34 is located near the closing part 36.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a welding torch used for consumable electrode gas-shielded arc welding. [Background technology]

[0002] This type of welding torch is a component that feeds power to a wire fed from a wire feeder using a power feed tip, and pays out the wire while covering it with shielding gas sprayed from a nozzle. Its structure is shown, for example, in Patent Document 1.

[0003] In the welding torch disclosed in Patent Document 1, the path of the shielding gas is set as follows.

[0004] The nozzle comprises a cylindrical tip body having a central hole, and an orifice member fitted onto the tip body to form a cylindrical annular space between the tip body and its outer periphery. The tip body is provided with a first ejection hole that connects from the central hole to the annular space, and the orifice member is provided with a second ejection hole that connects from the annular space to the space inside the nozzle.

[0005] The shielding gas is introduced into the nozzle space from the center hole of the tip body through the first nozzle hole, the annular space formed by the orifice member, and the second nozzle hole, and is sprayed from the nozzle tip so as to surround the wire.

[0006] In the configuration described in Patent Document 1, the space inside the nozzle extends further toward the base end of the torch than the second nozzle hole, which causes a drift including the generation of vortices in the gas flow that is ejected from the second nozzle hole and attempts to move through the space inside the nozzle toward the tip of the torch. This can cause a shortening of the laminar flow length of the gas flow ejected from the nozzle tip, resulting in a decrease in welding quality. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2014-213359 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention was conceived in light of the above-mentioned circumstances, and an object of the present invention is to provide a welding torch that can extend the laminar flow length of the shielding gas flow injected from the nozzle tip and further improve welding quality. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention employs the following technical means.

[0010] That is, 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 it and the tip body, and a cylindrical nozzle arranged radially outside the orifice member via a second annular space and having a tip on one side of the axial direction, wherein the tip body has a first ejection hole communicating from the internal space of the tip body to the first annular space, and the orifice member has a second ejection hole communicating from the first annular space to the second annular space, and the welding torch is characterized in that the second annular space is substantially closed by a sealing portion on the other side of the axial direction, and the outlet opening of the second ejection hole is positioned very close to the sealing portion.

[0011] In a preferred embodiment, the blocking portion is formed by forming a large diameter portion at the other end of the orifice member in the axial direction and bringing the outer periphery of the large diameter portion into contact with or close to the inner circumferential surface of the nozzle.

[0012] In a preferred embodiment, one side surface of the large diameter portion in the axial direction is a tapered surface that increases in diameter toward the other side in the axial direction, and the outlet opening of the second ejection hole is positioned on the tapered surface.

[0013] In a preferred embodiment, a cylindrical insulator fitted onto the tip body is disposed on the other axial side of the orifice member, and the inner periphery of the other axial end of the nozzle is connected to the outer periphery of the insulator by a fine metric thread.

[0014] In a preferred embodiment, a tapered flow straightening wall is formed on the inner peripheral surface of the nozzle at a position radially opposite the outlet opening of the second ejection hole, the diameter of which decreases toward the other side in the axial direction. [Effects of the Invention]

[0015] In the welding torch having the above configuration, the shielding gas introduced into the internal space of the tip body is discharged into the nozzle internal space (second annular space) via the first nozzle hole, the first annular space, and the second nozzle hole, and is sprayed from the nozzle tip (one end in the axial direction) as a jet that surrounds the welding wire.

[0016] Furthermore, because the nozzle internal space (second annular space) is substantially closed by a blocking portion on the base end side of the nozzle (the other side in the axial direction), and the outlet opening of the second nozzle hole is positioned very close to the blocking portion, the shielding gas discharged from the second nozzle hole is prevented from flowing toward the base end through the nozzle internal space, reducing drift caused by vortex generation and allowing the shielding gas to flow smoothly toward the tip end. As a result, the laminar flow length of the gas flow injected from the nozzle tip is extended, ensuring a sufficient shielding width by the shielding gas at the part to be welded, and improving weld quality.

[0017] Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the drawings. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a vertical cross-sectional view of a welding torch according to a first embodiment of the present invention. [Figure 2]FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. [Figure 5] FIG. 4 is a vertical cross-sectional view of a welding torch according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Preferred embodiments of the present invention will now be described in detail with reference to the drawings.

[0020] 1 to 4 show a welding torch A1 according to a first embodiment of the present invention. This welding torch A1 includes a torch body 1, a tip body 2, an orifice member 3, a nozzle 4, an insulator 5, a power feed tip 7, and a guide liner 8.

[0021] The tip body 2 is cylindrical and connected to the tip of the torch body 1. The tip body 2 extends in the direction of the axis Ox and has a cylindrical inner circumferential surface 12. The area surrounded by this inner circumferential surface 12 corresponds to an internal space 24 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. The tip body 2 also forms a first annular space 21 in cooperation with the orifice member 3 (described later), and has a first nozzle hole 22 that communicates from the internal space 24 to the first annular space 21, which will be described in detail later.

[0022] A cylindrical power feed tip 7 is connected to the tip end (one side in the direction of the axis Ox) of the tip body 2 by a screw means 71. The power feed tip 7 is made of a conductive metal material and is electrically connected to the tip body 2. The power feed tip 7 also has a wire guide hole 72 coaxial with the axis Ox, and contacts the wire that is inserted through the wire guide hole 72 and fed out from the tip end, thereby supplying welding current to the wire.

[0023] The orifice member 3 is disposed radially outward of the tip body 2 and has a cylindrical shape as a whole. As shown in FIGS. 1 and 4, the orifice member 3 has a large-diameter portion 31 on the base end side (the other side in the direction of the axis Ox), a medium-diameter portion 32 having a cylindrical outer surface in the middle portion in the direction of the axis Ox, and a tapered outer surface portion 33 on the tip end side (one side in the direction of the axis Ox) that decreases in diameter toward the tip. The inner periphery of the tapered outer surface portion 33 on the tip side of the orifice member 3 is fixed to the tip body 2 by a screw means 331. The orifice member 3 also has a second ejection hole 34 that communicates from the first annular space 21 with an internal space 41 (second annular space 411) of the nozzle 4, which will be described later.

[0024] The insulator 5 has a cylindrical shape as a whole, and is adjacent to the base end side (the other side in the direction of the axis Ox) of the orifice member 3, with its inner periphery connected to the outer periphery of the tip body 2 by a screw means 51. The tip of the torch body 1 together with its outer cover member 13 is inserted and connected to a receiving hole 52 formed in an expanded diameter at the rear end of the insulator 5.

[0025] The nozzle 4 is a cylindrical member extending coaxially with the axis Ox, with its tip end (one side in the direction of the axis Ox) slightly reduced in diameter and open, and the inner periphery of its base end (the other side in the direction of the axis Ox) connected to the outer periphery of the insulator 5 by a screw means 42. The internal space of this nozzle 4 forms a second annular space 411 between itself and the outer periphery of the orifice member 3. In this embodiment, a fine metric screw is particularly adopted as the screw means 42.

[0026] Guide liner 8 is disposed in internal space 12 of torch body 1 and internal space 24 of tip body 2. Guide liner 8 is flexible and tubular, and functions to guide a wire (not shown) by inserting the wire through guide liner 8. The wire fed to welding torch A1 is guided by guide liner 8 in internal space 11 of torch body 1 and internal space 24 of tip body 2, passes through wire guide hole 72 in power feed tip 7, and is led out from the tip of power feed tip 7.

[0027] 1, the first annular space 21 is formed by providing an annular concave outer surface portion 25, which is a reduced diameter portion of the outer peripheral surface of the tip body 2 over a certain length in the direction of the axis Ox, and by providing an annular concave inner surface portion 35, which is a increased diameter portion of the inner peripheral surface of the orifice member 3 over a certain length in the direction of the axis Ox. This first annular space 21 only needs to be formed between the outer peripheral surface of the tip body 2 and the inner peripheral surface of the orifice member 3. If the tip body 2 is provided with the annular concave outer surface portion 25, the orifice member 3 does not need to be provided with the annular concave inner surface portion 35, and if the orifice member 3 is provided with the annular concave inner surface portion 35, the tip body 2 does not need to be provided with the annular concave outer surface portion 25.

[0028] The first ejection holes 22 may be provided so as to communicate from the internal space 24 of the tip body 2 to the first annular space 21, but in this embodiment, they are formed on the tip side (one side in the direction of the axis Ox) of the first annular space 21. As shown in Fig. 2, the first ejection holes 22 are formed at multiple locations around the circumferential direction of the tip body 2, for example, four locations spaced 90 degrees apart.

[0029] As shown in FIG. 1, the base end side (the other side in the direction of the axis Ox) of the second annular space 411 is substantially closed by a sealing portion 36 formed by bringing the outer periphery 311 of the large diameter portion 31 on the base end side of the orifice member 3 into contact with or close to the inner circumferential surface 43 of the nozzle 4.

[0030] The second ejection holes 34 provided in the orifice member 3 are provided so that their outlet openings 341 are located in close proximity to the blocking portion 36. In this embodiment, the side surface on one side in the direction of the axis Ox of the large-diameter portion 31 of the orifice member 3 (the tip side of the nozzle 4) is formed as a tapered surface 312 whose diameter increases toward the other side in the direction of the axis Ox, and the outlet openings 341 of the second ejection holes 34 are located on this tapered surface 312. In this embodiment, the second ejection holes 34 are in the form of circular holes penetrating the orifice member 3 in the radial direction, but the outlet openings 341 are elliptical in shape and larger in cross-sectional area than the second ejection holes 34. As shown in FIG. 3 , the second ejection holes 34 are provided at a plurality of locations, for example, approximately 12 locations, at equal intervals in the circumferential direction of the orifice member 3.

[0031] Next, the operation of the welding torch A1 according to this embodiment will be described.

[0032] In the welding torch A1 having the above configuration, the shielding gas introduced into the internal space 24 of the tip body 2 is guided to the internal space 41 (second annular space 411) of the nozzle 4 via the first nozzle hole 22, the first annular space 21, and the second nozzle hole 34, as shown by the arrows in FIG. 1, and is sprayed as a jet that surrounds the wire (not shown) from the tip end (one side in the direction of the axis Ox) of the nozzle 4.

[0033] The internal space 41 (second annular space 411) of the nozzle 4 is substantially closed by the closing portion 36 on the base end side (the other side in the direction of the axis Ox) of the nozzle 4, and the outlet openings 341 of the second ejection holes 34 are positioned in close proximity to the closing portion 36. Therefore, the shielding gas discharged from the second ejection holes 34 is prevented from flowing through the internal space 41 (second annular space 411) of the nozzle 4 toward the base end side (the other side in the direction of the axis Ox). This reduces drift of the shielding gas due to vortex generation, allowing the shielding gas to be smoothly directed toward the tip side. As a result, the laminar flow length of the gas flow ejected from the tip of the nozzle 4 is extended, ensuring a sufficient shield width by the shielding gas at the welding target area and improving weld quality.

[0034] In this embodiment, the second nozzle hole 34 has an outlet opening 341 positioned on a tapered surface 312 formed on the large-diameter portion 31 of the orifice member 3. This causes a component of the gas flow discharged from the second nozzle hole 34 to be inclined obliquely forward (to one side in the direction of the axis Ox), which causes the gas flow to smoothly change direction toward the nozzle tip, thereby further reducing the generation of vortices in the gas flow flowing through the internal space 41 of the nozzle 4 and the resulting drift. Moreover, the size of the outlet opening 341 of the second nozzle hole 34 is larger than the cross-sectional area of ​​the second nozzle hole 34 (the shape of the outlet opening 341 is elliptical), which reduces pressure loss when gas is ejected from the second nozzle hole 34. This allows the shielding gas to be ejected more efficiently from the tip of the nozzle 4.

[0035] Furthermore, in this embodiment, a metric fine thread is particularly employed as thread means 42 connecting the inner periphery of the base end side (the other side in the direction of axis Ox) of nozzle 4 to the outer periphery of insulator 5. This makes it possible to suppress gas leakage from internal space 41 of nozzle 4 to the base end side (the other side in the direction of axis Ox) of welding torch A1, compared to using, for example, a trapezoidal thread as thread means 42, which also leads to savings in shielding gas or more efficient shielding by the shielding gas. Furthermore, nozzle 4 can be more accurately positioned coaxially with tip body 2 or power feed tip 7, which also allows shielding gas to properly surround the area to be welded, resulting in improved weld quality.

[0036] 5 shows the main parts of a welding torch A2 according to a second embodiment of the present invention. In the figure, the same reference numerals are used to designate the same or similar members or parts as those of the welding torch A1 according to the first embodiment, and the description thereof will be omitted as appropriate.

[0037] In this welding torch A2, the large diameter portion 31 formed on the rear end side (the other side in the direction of the axis Ox) of the orifice member 3 is flange-shaped, and the second ejection hole 34 is provided very close to the front side (one side in the direction of the axis Ox) of the large diameter portion 31. Meanwhile, a tapered flow straightening wall 45 is integrally formed in an annular shape on the inner peripheral surface of the nozzle 4 at a position radially opposite the outlet opening 341 of the second ejection hole 34 of the nozzle 4, and the diameter of the flow straightening wall 45 increases as it moves toward the front side (the other side in the direction of the axis Ox).

[0038] With this configuration, the shielding gas discharged from the second nozzle holes 34 does not flow toward the base end (the other side in the direction of the axis Ox) in the internal space 41 (second annular space 411) of the nozzle 4, but is all diverted toward the front side of the internal space 41 of the nozzle 4 (the other side in the direction of the axis Ox) by the flow-straightening wall 45. This significantly reduces the drift of the shielding gas caused by the generation of vortices, allowing the shielding gas to be smoothly directed toward the tip side. As a result, the laminar flow length of the gas flow ejected from the tip of the nozzle 4 is extended, ensuring a sufficient shield width by the shielding gas at the welding target portion, and improving weld quality.

[0039] Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to the above-described embodiments, and all modifications within the scope of the matters described in each claim are all included in the scope of the present invention. [Explanation of symbols]

[0040] A1, A2: welding torch, 2: tip body, 21: first annular space, 22: first nozzle hole, 24: internal space, 3: orifice member, 31: large diameter portion, 312: tapered surface, 34: second nozzle hole, 341: outlet opening, 36: sealing portion, 4: nozzle, 411: second annular space, 42: screw means, 43: inner peripheral surface, 5: insulator,

Claims

1. A welding torch comprising: a cylindrical tip body extending in an axial direction; an orifice member disposed radially outside the tip body and forming a first annular space between the tip body and the orifice member; and a cylindrical nozzle disposed radially outside the orifice member with a second annular space interposed therebetween and having a tip on one side in the axial direction, wherein the tip body has a first ejection hole communicating from an internal space of the tip body to the first annular space, and the orifice member has a second ejection hole communicating from the first annular space to the second annular space, the second annular space is substantially closed by a closing portion on the other side in the axial direction, and the second ejection hole has an outlet opening positioned near the other end of the second annular space in the axial direction, a welding torch, characterized in that the sealing portion is formed by forming a large diameter portion at the other end of the orifice member in the axial direction and bringing the outer periphery of the large diameter portion into contact with or close to the inner circumferential surface of the nozzle.

2. 2. The welding torch according to claim 1, wherein a side surface on one side in the axial direction of the large diameter portion is a tapered surface whose diameter increases toward the other side in the axial direction, and the outlet opening of the second nozzle hole is positioned on the tapered surface.

3. 3. The welding torch according to claim 1, wherein a cylindrical insulator fitted onto the tip body is disposed on the other side of the orifice member in the axial direction, and the inner periphery of the other end of the nozzle in the axial direction is connected to the outer periphery of the insulator by a fine metric thread.

4. 2. The welding torch according to claim 1, wherein a tapered flow straightening wall having a diameter that decreases toward the other side in the axial direction is formed on an inner peripheral surface of the nozzle at a position radially opposite to the outlet opening of the second nozzle hole.

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