welding torch

Abstract

To provide a welding torch capable of reducing flow rate loss of shield gas and stably injecting shield gas from a nozzle tip by avoiding center misalignment of a nozzle and a chip body.SOLUTION: A welding torch comprises: a cylindrical chip body 2 extending in an axial direction; an orifice member 3 arranged on a radially outer side of the chip body 2; and a cylindrical nozzle 4 arranged on a radially outer side of the orifice member 3 and having a tip on one side in an axis Ox direction. Shield gas introduced into an inner space of the chip body 2 is injected from the tip of the nozzle 4 via the orifice member 3. The nozzle 4 is fastened, on the other side in the axis Ox direction, to a torch front body 14 by screw means 42, and an annular, elastic seal member 52 is arranged between the nozzle 4 on the one side in the axis Ox direction relative to the screw means 42 and the torch front body 14.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 nozzle, which surrounds the tip body to form an internal nozzle space, has its base end fastened to the front body (insulator) of the torch with a square screw or a trapezoidal screw.

[0006] The shielding gas is introduced into the nozzle space from the central 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 then sprayed from the nozzle tip so as to surround the wire.

[0007] In the configuration described in Patent Document 1, the nozzle has its base end fastened to the front body of the torch with a square or trapezoidal thread, and therefore the shielding gas introduced into the nozzle interior space from the second nozzle hole of the orifice member leaks from the base end of the nozzle interior space through gaps in the fastening portion of the square or trapezoidal thread to the outside, which can lead to a loss of flow rate of the shielding gas.

[0008] In the configuration described in Patent Document 1, the fastening parts using square or trapezoidal threads are prone to loosening, which can cause the axis of the nozzle to become misaligned with the axis of the tip body. In this case, the gas flow sprayed from the nozzle tip becomes uneven, deteriorating shielding properties and potentially reducing the quality of the weld. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent Publication No. 2014-213359 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention was conceived in light of the above-mentioned circumstances, and its object is to provide a welding torch that can reduce the flow loss of shielding gas, prevent misalignment between the nozzle and the tip body, and ensure stable injection of shielding gas from the nozzle tip. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention employs the following technical means.

[0012] 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 a cylindrical nozzle arranged radially outside the orifice member and having a tip on one side in the axial direction, and in which shielding gas introduced into the internal space of the tip body is sprayed from the tip of the nozzle via the orifice member, the other side of the nozzle in the axial direction is fastened to the torch front body by a screw means, and an annular elastic seal member is provided between the nozzle and the torch front body on one side in the axial direction of the screw means.

[0013] In a preferred embodiment, the cooling structure is a water-cooled type.

[0014] In a preferred embodiment, the resilient sealing member is an O-ring.

[0015] In a preferred embodiment, the thread means employs fine threads. [Effects of the Invention]

[0016] In the welding torch having the above configuration, the shielding gas introduced into the internal space of the tip body is guided through the orifice member into the internal space of the nozzle and is sprayed from the tip of the nozzle (one end in the axial direction) as a jet that surrounds the welding wire.

[0017] The nozzle is fastened to the torch front body at its base end (the other axial side) by a screw means. In the welding torch having the above configuration, an annular elastic seal member is provided between the nozzle and the torch front body on one axial side (the nozzle tip side) of the screw means. This effectively prevents the shielding gas introduced into the nozzle space via the orifice member from leaking to the outside through gaps in the screw means. As a result, the flow loss of the shielding gas can be reduced. The elastic seal member also has the effect of preventing loosening of the fastened portion by the screw means.

[0018] If the welding torch has a water-cooling structure, an inexpensive O-ring can be used as the elastic sealing member, and it can withstand use without worrying about deterioration due to heat.

[0019] Furthermore, when a fine thread is used as the threading means, loosening of the threaded fastening portion is less likely to occur and the gaps present can be minimized, which, combined with the sealing function of the elastic seal member, further enhances the effectiveness of preventing leakage of the shielding gas. In addition, misalignment of the nozzle and tip body due to loosening of the threaded fastening portion can be prevented, and the stability of the shielding gas spray from the nozzle tip can be maintained.

[0020] 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]

[0021] [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 an enlarged view of a main part of FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 2 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 2 is a cross-sectional view taken along line VI-VI in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the present invention will now be described in detail with reference to the drawings.

[0023] 1 to 6 show a welding torch A1 according to one embodiment of the present invention. This welding torch A1 has a water-cooled cooling structure and basically includes a torch body 1, a tip body 2, an orifice member 3, a nozzle 4, a power feed tip 7, and a guide liner 8. Torch body 1 includes a torch front body 14 at its tip, and torch front body 14 includes a cooling circuit component 6 and an insulator 5.

[0024] The tip body 2 is cylindrical and is connected to the tip of the torch body 1, i.e., torch front body 14. 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 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.

[0025] 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.

[0026] 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 2, 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 intermediate 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.

[0027] The torch front body 14 includes an inner cylinder 141 adjacent to the other side of the tip body 2 in the direction of the axis Ox, an intermediate cylinder 142 adjacent to the other side of the orifice member 3 in the direction of the axis Ox and whose inner circumferential surface is continuous with the inner circumferential surface 11 of the torch body 1, a cooling circuit component 6 fitted onto the intermediate cylinder 142, and an insulator 5 fitted onto the cooling circuit component 6. The cooling circuit component 6 and the insulator 5 are both cylindrical as a whole. The tip of the inner cylinder 141 (one side in the direction of the axis Ox) is joined to the rear end of the tip body 2 and serves as a power supply path to the tip body 2.

[0028] An outgoing path 15 and an inward path 16 for cooling water are formed in the space between the inner surface 11 of the intermediate tube 142 or torch body 1 and the outer surface of the inner tube 141, and these outward path 15 and inward path 16 are connected to a cooling water inlet port and a cooling water recovery port, respectively, not shown, which are provided at the base end of the torch body 1.

[0029] 1, 2, and 5, the outer surface of the cooling circuit component 6 and the inner surface of the insulator 5 cooperate to form an annular cooling water passage 61, and cooling water is introduced into the annular cooling water passage 61 from outward water passage holes 62 provided in the intermediate cylinder 142 and the cooling circuit component 6 so as to communicate with the outward passage 15, as shown by the arrows in Figures 2 and 5, and this cooling water is returned to the return passage 16 from return water passage holes 63 provided in the intermediate cylinder 142 and the cooling circuit component 6 so as to communicate with the return passage 16. By having such a cooling structure, the area around the torch front body 14, which is affected by the heat from the welding arc, can be protected from thermal deformation and unwanted spatter adhesion.

[0030] An O-ring 64 is provided on the inner periphery of the cooling circuit component 6 as needed to ensure watertightness between the cooling circuit component 6 and the intermediate cylinder 142, and an O-ring 65 is provided on the outer periphery of the cooling circuit component 6 as needed to ensure watertightness between the cooling circuit component 6 and the insulator 5. A nut member 17 having a cap portion 171 that covers the outer periphery of the rear end portion of the insulator 5 is screwed onto the cooling circuit component 6, further ensuring the watertightness maintaining function of the O-ring 65.

[0031] 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 (torch front body 14) 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 thread, such as a metric fine thread, is particularly adopted as the screw means 42.

[0032] Furthermore, an annular groove 51 is formed on the outer peripheral surface of the insulator 5 on one side of the screw means 42 in the direction of the axis Ox, and an O-ring 521 as an example of an elastic sealing member 52 is held in the annular groove 51, the outer periphery of which is elastically pressed against the inner peripheral surface of the nozzle 4.

[0033] Guide liner 8 is disposed across the interior space of inner cylinder 141 and interior space 24 of tip body 2. Guide liner 8 is a flexible tube that guides a wire (not shown) by inserting the wire through it. The wire fed to welding torch A1 is guided by guide liner 8 in interior space 11 of torch body 1 or interior 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.

[0034] As shown in Figures 1 and 2, the first annular space 21 is formed by providing an annular concave outer surface portion 25, which is a portion of the outer peripheral surface of the tip body 2 that is narrowed in diameter over a certain length in the direction of the axis Ox, and by providing an annular concave inner surface portion 35, which is a portion of the inner peripheral surface of the orifice member 3 that is widened in diameter over a certain length in the direction of the axis Ox.

[0035] 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. 3, 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.

[0036] In this embodiment, the second ejection holes 34 provided in the orifice member 3 are formed such that the side surface on one side in the direction of the axis Ox (the tip side of the nozzle 4) of the large diameter portion 31 of the orifice member 3 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 positioned on this tapered surface 312. As shown in Fig. 4, the second ejection holes 34 are provided at a plurality of locations, for example, about 12 locations, at equal intervals in the circumferential direction of the orifice member 3.

[0037] Next, the operation of the welding torch A1 according to this embodiment will be described.

[0038] In the welding torch A1 having the above configuration, the shielding gas introduced into the internal space 24 of the tip body 2 is discharged into 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. 2, and is sprayed from the tip end (one side in the direction of the axis Ox) of the nozzle 4 as a jet that surrounds the wire (not shown).

[0039] The nozzle 4 has its base end (the other axial side) fastened to the torch front body 14 by the screw means 42. In the welding torch A1 having the above configuration, an annular elastic seal member 52 is provided between the nozzle 4 and the torch front body 14 on one side (the nozzle tip side) of the screw means 42 in the direction of the axis Ox. This effectively prevents the shielding gas introduced into the internal space 41 of the nozzle 4 via the orifice member 3 from leaking to the outside through gaps present in the screw means 42. As a result, the flow loss of the shielding gas can be reduced. The elastic seal member 52 also has the effect of preventing loosening of the fastened portion by the screw means 42.

[0040] The welding torch A1 according to this embodiment has a water-cooled cooling structure, and an inexpensively available O-ring 521 can be used as the elastic sealing member 52. This O-ring 521 can withstand use without the risk of deterioration due to heat.

[0041] In this embodiment, fine threads are used as the thread means 42 that fasten the nozzle 4 to the insulator 5 (torch front body 14). This makes it difficult for the threaded fastening portion to loosen and minimizes any gaps that may exist. This, combined with the sealing function of the elastic seal member 52 (O-ring 521), further enhances the effectiveness of preventing shielding gas leakage. In addition, it prevents misalignment between the nozzle 4 and the tip body 2 that could result from loosening of the threaded fastening portion, maintaining the stability of shielding gas spray from the nozzle tip.

[0042] In this embodiment, the second ejection hole 34 of the orifice member 3 has its outlet opening 341 positioned at the rear end of the second annular space 411, and therefore the shielding gas discharged from the second ejection hole 34 is prevented from flowing toward the base end side (the other side in the direction of the axis Ox) through the internal space 41 (second annular space 411) of the nozzle 4. This reduces the drift of the shielding gas caused by the generation of vortices and allows the shielding gas to flow smoothly toward the tip side, thereby extending the laminar flow length of the gas flow ejected from the tip of the nozzle 4 and ensuring a sufficient shield width by the shielding gas at the parts to be welded.

[0043] 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.

[0044] 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.

[0045] For example, in the above embodiment, the present invention is applied to a welding torch having a water-cooled cooling structure, but it does not matter whether it is water-cooled or not.

[0046] Furthermore, in the above embodiment, the part of the torch front body 14 to which the nozzle 4 is fastened with the screw means 42 is specifically the insulator 5, but this fastening object does not have to be the insulator 5. [Explanation of symbols]

[0047] A1: welding torch, 14: torch front body, 2: tip body, 3: orifice member, 4: nozzle, 42: screw means, 52: elastic seal member, 521: O-ring

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 a cylindrical nozzle disposed radially outside the orifice member and having a tip on one side in the axial direction, wherein shielding gas introduced into an internal space of the tip body passes through the orifice member and is sprayed from the tip of the nozzle, the nozzle is fastened to the torch front body at the other side in the axial direction by a screw means, a welding torch, characterized in that an annular elastic seal member is provided between the nozzle and the torch front body on one side of the screw means in the axial direction, for preventing the shielding gas from leaking to the outside from a fastening portion between the nozzle and the torch front body by the screw means.

2. The welding torch according to claim 1 , having a water-cooling type cooling structure.

3. 3. The welding torch of claim 2, wherein the resilient sealing member is an O-ring.

4. 4. The welding torch according to claim 1, wherein the screw means employs fine threads.

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