TIG welding torch

Abstract

To provide a TIG welding torch that is able to adjust the direction of a gas rectifying groove relative to a torch body, even in a state in which a narrowed nozzle is attached to the torch body.SOLUTION: The TIG welding torch 1 includes a torch body 2, a tungsten electrode rod 3, a gas lens 6, a shield nozzle 7, and a narrowed nozzle 8. The narrowed nozzle 8 has: two positioning protrusions 8c, 8c oppositely disposed on an inner peripheral surface of the nozzle body 8b; and two gas rectifying grooves 8d, 8d alternated with the two positioning protrusions 8c, 8c in a circumferential direction of the nozzle body 8b. The TIG welding torch 1 further includes a phase adjustment mechanism 9 capable of adjusting a phase of the narrowed nozzle 8 relative to the torch body 2 while the narrowed nozzle 8 is kept held at a predetermined axial position relative to the torch body 2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a torch for TIG welding.

Background Art

[0002] TIG welding is known as a welding technique with excellent versatility regardless of the material. This welding is performed using a welding torch with a tungsten electrode having an extremely high melting point, and by covering the periphery of the welded part with a shielding gas composed of an inert gas to make the work piece meltable, it has the advantage of avoiding the situation where oxygen in the air reacts with the molten metal and obtaining good welding quality over a long period.

[0003] Here, as a TIG welding torch used for TIG welding, for example, a TIG welding torch provided with a cylindrical shielding nozzle for discharging a shielding gas such as argon gas (for example, refer to Patent Document 1), or a TIG welding torch provided with the shielding nozzle and a constriction nozzle for increasing the energy density of the arc (for example, refer to Patent Document 2) is known.

[0004] Among these, according to the TIG welding torch provided with a shielding nozzle and a constriction nozzle, since the shielding gas can be concentratedly flowed from the constriction nozzle to the periphery of the arc, the energy density of the arc can be increased compared to a TIG welding torch provided with only the shielding nozzle. Therefore, the welding speed can be increased and the directivity of the arc can also be improved, but on the contrary, there is a problem that the discharge range of the shielding gas is narrowed and the shielding effect is weakened, resulting in a decrease in the quality of the welding.

[0005] Also, when replacing the tungsten electrode rod, it is difficult to set the tungsten electrode rod at the original position (the central position of the constriction nozzle), and there is a problem of poor reproducibility and workability.

[0006] Therefore, the applicant of the present application has proposed a constricted nozzle for TIG welding for the purpose of solving the above problems (see Patent Document 3). This constricted nozzle is arranged around the tip of the tungsten electrode rod, and includes a cylindrical nozzle body that forms an annular high-speed gas passage between the tip of the tungsten electrode rod and the outer peripheral surface of the tip of the tungsten electrode rod, and a plurality of positioning ridges that are formed to protrude from the inner peripheral surface of the nozzle body and hold the tungsten electrode rod at the central position of the nozzle body. The constricted nozzle is also composed of a plurality of gas rectifying grooves that are formed between the plurality of positioning ridges, extend parallel to the longitudinal direction of the nozzle body, and can rectify the shielding gas flowing in the high-speed gas passage.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] By using the constricted nozzle provided with the gas rectifying grooves as described above, a part of the shielding gas can be made into a high-speed rectifying gas that is faster than the laminarized shielding gas discharged from between the shielding nozzle and the constricted nozzle, and this high-speed rectifying gas can be made to flow around the arc. As a result, the electromagnetic force and magnetic field acting on the arc are strengthened, and the energy density, directivity, and stiffness of the arc are respectively increased, so that a stable arc can be obtained. Therefore, compared with the prior art, the welding speed can be increased in each stage, and the bead width can be made uniform on both the front and back surfaces, and the intervals of the bead waveforms can be formed at equal intervals, enabling high-quality and stable welding.

[0009] In addition, by projecting a plurality of positioning ridges for holding the tungsten electrode bar at the central position of the nozzle body on the inner peripheral surface of the nozzle body, when replacing the tungsten electrode bar, the tungsten electrode bar can be accurately and reliably set at the original position (the central position of the narrow nozzle), the reproducibility of the mounting position of the tungsten electrode bar can be improved, and the workability can be improved.

[0010] In particular, by using a narrow nozzle in which two positioning ridges and two gas rectifying grooves are alternately arranged in the circumferential direction of the nozzle body, the arc generated between the base material (welded material) can be narrowed into an elliptical shape. As a result, it becomes possible to further increase the energy density. In the case of butt welding, by narrowing the arc into an elliptical shape, the preheating effect is increased, the penetration becomes larger, and the back bead also easily appears. Furthermore, by making the major axis direction of the arc narrowed into an elliptical shape coincide with the welding direction, butt welding with a narrow bead width is also possible. Therefore, even when welding a material that is not suitable for TIG welding, such as an electromagnetic steel sheet whose surface is covered with an insulating material, by using a TIG welding torch equipped with the narrow nozzle according to the above configuration, high-quality and high-speed welding can be stably performed.

[0011] On the other hand, when performing TIG welding using a TIG welding torch equipped with the narrow nozzle having the above configuration, the mounting posture of the narrow nozzle with respect to the TIG welding torch becomes a problem. That is, in order to maximize the action effect of the narrow nozzle having the above configuration, it is necessary that the major axis direction of the elliptical arc coincides with the moving direction of the TIG welding torch. However, in a conventional TIG welding torch, the narrow nozzle and the gas lens, and the gas lens and the torch body are both fixed by screw fitting, and the mounting structure does not consider the mounting posture of the narrow nozzle with respect to the TIG welding torch (torch body). Therefore, when mounting and welding a TIG welding torch on a welding facility equipped with a mechanism for causing the TIG welding torch to perform a predetermined operation (for example, a sliding operation), in the state where the TIG welding torch is mounted on the welding facility, the fact is that the directions of the two gas rectifying grooves cannot be changed.

[0012] In view of the above circumstances, the technical problem to be solved by the present invention is to provide a TIG welding torch capable of adjusting the orientation of the gas rectifying groove with respect to the torch body even when a constriction nozzle is attached to the torch body.

Means for Solving the Problem

[0013] The solution to the above problem is achieved by a TIG welding torch according to the present invention. That is, this TIG welding torch includes a torch body, a gas lens disposed in the internal space of the torch body and capable of laminarizing the shielding gas flowing into the internal space, a cylindrical shielding nozzle disposed on the tip side of the torch body with respect to the gas lens, a tungsten electrode rod disposed at the center position of the shielding nozzle, and a constriction nozzle disposed between the shielding nozzle and the tip of the tungsten electrode rod. The constriction nozzle includes a cylindrical nozzle body that forms an annular high-speed gas passage between the outer peripheral surface of the tip of the tungsten electrode rod, two positioning ridges disposed opposite to the inner peripheral surface of the nozzle body and holding the tungsten electrode rod at the center position of the nozzle body, and two gas rectifying grooves adjacent to each positioning ridge in the circumferential direction of the nozzle body and capable of rectifying the shielding gas flowing in the high-speed gas passage. In the TIG welding torch, in a state where the constriction nozzle is held at a predetermined axial position with respect to the torch body, it is further characterized by having a phase adjustment mechanism capable of adjusting the phase of the constriction nozzle with respect to the torch body.

[0014] Thus, in the TIG welding torch according to the present invention, a phase adjustment mechanism capable of adjusting the phase of the constriction nozzle with respect to the torch body is provided while the constriction nozzle is held at a predetermined axial position with respect to the torch body. Therefore, even after the constriction nozzle is attached to the torch body, or even when the TIG welding torch with the constriction nozzle attached is set in the welding equipment, the phase of the constriction nozzle with respect to the torch body can be appropriately changed. Here, since the directions (circumferential positions) of the two gas rectifying grooves are always constant with respect to the constriction nozzle, it is possible to freely change the direction of the gas rectifying grooves by adjusting the phase of the constriction nozzle. Therefore, at any time, the direction of the gas rectifying grooves can be adjusted to match the welding direction (the moving direction of the TIG welding torch), and the TIG welding torch can be used with high performance without being restricted in the usage mode.

[0015] Further, in the TIG welding torch according to the present invention, the phase adjustment mechanism includes an annular recess formed on the outer peripheral surface of the constriction nozzle or the outer peripheral surface of the gas lens to which the constriction nozzle is fixed, and a pushing member disposed at a position radially opposed to the annular recess among the torch body and the shield nozzle, the pushing member being movable in the radial direction and pushable against the bottom surface of the annular recess. The constriction nozzle or the gas lens fixed to the constriction nozzle may be fitted to the torch body so as to be axially rotatable.

[0016] By configuring the phase adjustment mechanism in this way, in the state where the pushing member is pushed against the bottom surface of the annular recess, the phase of the constriction nozzle with respect to the torch body can be fixed. Further, by releasing the pushing state by the pushing member, the constriction nozzle can be axially rotated with respect to the torch body to freely change the phase of the constriction nozzle. From the above, according to the TIG welding torch according to this configuration, it is possible to adjust the direction of the gas rectifying grooves with a simple structure and a simple operation.

[0017] Further, in this case, in the TIG welding torch according to the present invention, the pushing member and the annular recess may be engaged in the axial direction in the state where the pushing member is pushed against the bottom surface of the annular recess.

[0018] By configuring the pushing member and the annular recess to engage with each other in the axial direction in this way, the constriction nozzle can be more firmly fixed to the torch body so as not to be axially rotatable. Therefore, after the phase alignment, it is possible to avoid as much as possible the situation where the phase is shifted due to unexpected contact or the like, and start TIG welding in a state where the direction of the gas rectifying groove is surely set according to the welding direction.

[0019] Further, when the phase adjustment mechanism has the annular recess and the pushing member as described above, in the TIG welding torch according to the present invention, the constriction nozzle is fixed to the gas lens, the shield nozzle is fixed to the gas lens, the annular recess is provided on the outer peripheral surface of the gas lens, and the pushing member may be a set screw that is screwed into a female screw hole penetrating the torch body in the radial direction.

[0020] With the constriction nozzle and the shield nozzle fixed to the gas lens in this way, an annular recess is provided on the outer peripheral surface of the gas lens, and a set screw as a pushing member is configured to be screw-fittable into a female screw hole penetrating the torch body in the radial direction. By doing so, it is possible to very easily move the set screw in the radial direction by an external operation, and easily switch between the axially rotatable state and the restricted state of the constriction nozzle. Therefore, according to the TIG welding torch according to this configuration, it is possible to extremely easily perform the phase alignment of the constriction nozzle and thus adjust the direction of the gas rectifying groove.

[0021] Further, in the TIG welding torch according to the present invention, a mark indicating the circumferential position of the gas rectifying groove may be provided on the outer peripheral surface of the portion of the constriction nozzle that protrudes beyond the shield nozzle.

[0022] The orientation (circumferential position) of the gas rectifying groove with respect to the torch body can be visually recognized from the opening side of the constriction nozzle. However, depending on the mounting mode of the TIG welding torch, it is assumed that there may be cases where it is difficult to visually recognize from the opening side of the constriction nozzle. In this regard, since the outer peripheral surface of the portion of the constriction nozzle that protrudes beyond the shield nozzle is always visible from the outside regardless of the viewing direction, by providing a mark on the outer peripheral surface of this tip portion, the orientation of the gas rectifying groove can be easily confirmed.

[0023] Alternatively, in the TIG welding torch according to the present invention, the constriction nozzle may be fixed to the gas lens at a predetermined circumferential position, and the shield nozzle may be fixed to the gas lens at a predetermined circumferential position, and a mark indicating the circumferential position of the gas rectifying groove may be provided on the outer peripheral surface of the shield nozzle.

[0024] Also, as described above, when the phase in the fixed state of the constriction nozzle with respect to the shield nozzle is known in advance, a mark indicating the circumferential position of the gas rectifying groove can also be provided on the outer peripheral surface of the shield nozzle. In this case, since it is easier to confirm the mark than when providing a mark on the tip portion of the constriction nozzle, it becomes possible to adjust the orientation of the gas rectifying groove more simply.

Effect of the Invention

[0025] As described above, according to the TIG welding torch of the present invention, even when the constriction nozzle is attached to the torch body, it is possible to adjust the orientation of the gas rectifying groove with respect to the torch body.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0027] Hereinafter, the content of the torch for TIG welding according to an embodiment of the present invention will be described with reference to the drawings.

[0028] FIG. 1 is a cross-sectional view of the torch 1 for TIG welding according to the present embodiment, and FIGS. 2 and 3 show a side view and a front view of the torch 1 for TIG welding, respectively. This torch 1 for TIG welding is mainly used when butt-welding the ends of metal thin plates such as stainless steel plates and electromagnetic steel plates. It includes a cylindrical torch body 2 through which a shielding gas G such as argon gas or helium gas passes, an electrode collet 4 that is screwed and inserted into the torch body 2 from above so as to be vertically movable and rotatable, and detachably holds a tungsten electrode bar 3, a collet handle 5 attached to the upper end of the electrode collet 4, which rotates the electrode collet 4 forward and backward to move it up and down with respect to the torch body 2, a gas lens 6 detachably attached to the lower end of the torch body 2, which uniformly diffuses and laminarizes the shielding gas G flowing in through the inside of the torch body 2, a cylindrical shielding nozzle 7 detachably attached to surround the tip of the tungsten electrode bar 3 on the gas lens 6 or the torch body 2, and discharges the shielding gas G laminarized by the gas lens 6 around the arc, a constriction nozzle 8 disposed around the tip of the tungsten electrode bar 3 and flowing a linear high-speed rectifying gas around the arc, and a phase adjustment mechanism 9 capable of adjusting the phase of the constriction nozzle with respect to the torch body.

[0029] In FIGS. 1 and 2, reference numeral 10 denotes a pressure adjustment screw provided on the torch body 2, which gives an appropriate rotational resistance to the electrode collet 4 and holds the electrode collet 4 in an adjusted position. Reference numeral 11 denotes an O-ring for sealing between the torch body 2 and the collet handle 5. Reference numeral 12 denotes an adjustment ring made of plastic interposed between the torch body 2 and the shield nozzle 7.

[0030] As shown in FIGS. 2 and 3, the torch body 2 is composed of a square tube portion formed of a metal material such as an aluminum alloy and a cylindrical portion continuously provided at the upper end of the square tube portion. On the peripheral wall of the square tube portion, an electrode / main gas pipe connection fitting (both not shown) for connecting the main gas supply pipe and the power cable, and the pressure adjustment screw 10 are inserted and fixed. Further, on the inner peripheral surface of the upper end opening of the torch body 2, a female screw portion 2a is formed into which an electrode collet 4 for holding the tungsten electrode bar 3 is screwed so as to be vertically movable.

[0031] As shown in FIG. 1, the electrode collet 4 is formed in an elongated cylindrical shape having a half-cut chuck portion at the tip end. A male screw portion 4a that is screwed onto the female screw portion 2a on the upper end side of the torch body 2 so as to be vertically movable is formed on a part of the outer peripheral surface. The electrode collet 4 is composed of a copper-made collet body 4' and a copper-made cylindrical fixture 4'' that is detachably screwed onto the outer peripheral surface of the chuck portion of the collet body 4' and tightens the chuck portion to fix the tungsten electrode bar 3 inserted through the collet body 4'. This electrode collet 4 is screwed into the torch body 2 from the upper side, and it moves up and down in the torch body 2 by rotating the collet handle 5 fixed to the upper end portion of the collet body 4'.

[0032] The gas lens 6 is composed of a holder 6' made of copper and having a cylindrical structure that can be held at a predetermined axial position with respect to the torch body 2, and a metal filter 6'' attached to the holder 6'.

[0033] Specifically, as shown in FIGS. 2 and 3, the holder 6' is formed as a cylindrical body with a gas passage 6a formed in its central part. The upper end of the holder 6' is axially rotatably fitted (loosely fitted) to the inner circumference of the lower end of the torch body 2. Further, at the lower end of the holder 6', a cylindrical holding cylinder part 6c having a male screw part 6b on its outer peripheral surface to which the shield nozzle 7 is detachably screwed, and a support cylinder part 6e having a female screw part 6d formed at the center of the holding cylinder part 6c and to which the constriction nozzle 8 is detachably screwed on its inner peripheral surface are respectively formed. Thereby, both the shield nozzle 7 and the constriction nozzle 8 can be fixed to the gas lens 6 by screw fitting. Further, the space between the holding cylinder part 6c and the support cylinder part 6e of the holder 6' forms an annular gas chamber 6f, and is communicated with the inside of the torch body 2 through a plurality of gas flow holes 6g formed near the base end of the support cylinder part 6e and the gas passage 6a of the holder 6'.

[0034] On the other hand, the filter 6″ is formed by laminating a plurality of annularly punched wire meshes, and is attached to the holder 6' by fitting its inner peripheral edge to the support cylinder part 6e of the holder 6' and its outer peripheral edge to the holding cylinder part 6c of the holder 6'.

[0035] As shown in FIGS. 1 to 3, the shield nozzle 7 is formed in a cylindrical shape with its tip constricted by a ceramic material. A female screw part 7a that is detachably screwed to the male screw part 6b of the holding cylinder part 6c of the gas lens 6 is formed on a part of its inner peripheral surface. The shield nozzle 7 is attached to the outer peripheral surface of the gas lens 6 by screwing its female screw part 7a into the male screw part 6b of the holding cylinder part 6c of the gas lens 6, and discharges the shield gas G that has passed through the filter 6″ of the gas lens 6 and has been made laminar around the tip of the tungsten electrode rod 3.

[0036] As shown in Fig. 1, the constriction nozzle 8 is disposed around the tip of the tungsten electrode rod 3 to form an annular high-speed gas passage 8a between the constriction nozzle 8 and the tip of the tungsten electrode rod 3. A part of the shielding gas G flowing from within the torch body 2 into the gas passage 6a of the holder 6' of the gas lens 6 is made to flow into the high-speed gas passage 8a to serve as a high-speed rectifying gas that is faster than the laminarized shielding gas G flowing around the constriction nozzle 8 from the shielding nozzle 7, and the high-speed rectifying gas is caused to flow around the arc.

[0037] That is, the constriction nozzle 8 is formed as a cylindrical body from a copper material (beryllium copper) excellent in conductivity, strength, etc. As shown in Figs. 1 and 4, it is arranged concentrically with the tungsten electrode rod 3 around the tip of the tungsten electrode rod 3, and has a cylindrical nozzle body 8b that forms an annular high-speed gas passage 8a between the nozzle body 8b and the outer peripheral surface of the tip of the tungsten electrode rod 3, two positioning ridges 8c, 8c that are arranged opposite to the inner peripheral surface of the nozzle body 8b and hold the tungsten electrode rod 3 at the central position of the nozzle body 8b, and two gas rectifying grooves 8d, 8d that are alternately arranged in the circumferential direction with the two positioning ridges 8c, 8c and can rectify the shielding gas G flowing in the high-speed gas passage 8a.

[0038] Here, each positioning ridge 8c extends along the longitudinal direction of the nozzle body 8b. Similarly, each gas rectifying groove 8d also extends along the longitudinal direction of the nozzle body 8b (see Fig. 1). Further, in this embodiment, the side surface 8c1 of each positioning ridge 8c has a flat surface shape and extends linearly in a direction orthogonal to the facing direction of the two gas rectifying grooves 8d, 8d (see Fig. 4).

[0039] By alternately providing the two positioning ridges 8c, 8c and the two gas rectifying grooves 8d, 8d at 90° intervals in the circumferential direction as described above, an arc having an elliptical cross-sectional shape can be formed as will be described later. At that time, the major axis direction of the ellipse (the longitudinal direction of the arc) coincides with the longitudinal direction of the gas rectifying groove 8d (the vertical direction in Fig. 4).

[0040] The positioning protrusion 8c and the gas rectifying groove 8d having the above-described configuration are formed at positions separated upward from the tip of the nozzle body 8b, and the inner diameter of the high-speed gas passage 8a located on the downstream side of the positioning protrusion 8c and the gas rectifying groove 8d is formed larger than the inner diameter of the high-speed gas passage 8a located on the upstream side of the positioning protrusion 8c and the gas rectifying groove 8d. As a result, the shielding gas G flowing into the high-speed gas passage 8a passes through the gas rectifying groove 8d and is rectified into high-speed rectified gas, and can be discharged from the tip opening of the nozzle body 8b after being stabilized in the downstream portion of the high-speed gas passage 8a.

[0041] The tip portion (lower end portion) of the nozzle body 8b is formed in a tapered shape, and a male screw portion 8e that is detachably screwed to the support cylinder portion 6e of the holder 6' of the gas lens 6 is formed on the outer peripheral surface of the base end portion (upper end portion) of the nozzle body 8b. Therefore, by screwing the male screw portion 8e into the support cylinder portion 6e, the constricted nozzle 8 is attached to the central position of the tip surface of the gas lens 6.

[0042] The phase adjustment mechanism 9 enables adjustment of the phase of the constricted nozzle 8 with respect to the torch body 2 in a state where the constricted nozzle 8 is held at a predetermined axial position with respect to the torch body 2. In the present embodiment, as shown in FIG. 5, an annular recess 9a formed on the outer peripheral surface of the upper end of the holder 6' of the gas lens 6 to which the constricted nozzle 8 is fixed, and disposed at a position radially opposed to the annular recess 9a in the torch body 2, and having a pushing member 9b that is movable in the radial direction and can be pushed into the bottom surface 9a1 of the annular recess 9a.

[0043] Here, the upper end of the holder 6' of the gas lens 6 fixed to the narrowing nozzle 8 is fitted so as to be axially rotatable with respect to the inner circumference of the lower end of the torch body 2 as described above. Therefore, in a state where the pushing member 9b is retracted in a direction away from the annular recess 9a, by axially rotating the narrowing nozzle 8 or the shield nozzle 7, the phase of the narrowing nozzle 8 with respect to the torch body 2 can be changed. Further, as shown in FIG. 5, in a state where the pushing member 9b is pushed into the bottom surface 9a1 of the annular recess 9a, the axial movement of the holder 6' of the gas lens 6 with respect to the torch body 2 is restricted by the pushing force of the pushing member 9b, and the circumferential movement (axial rotation) is also restricted.

[0044] Further, in the present embodiment, a chamfered portion 9b1 is provided at the tip of the pushing member 9b. This chamfered portion 9b1 has a function of guiding the holder 6' of the gas lens 6 to a predetermined axial position by engaging with the annular recess 9a in the axial direction during the pushing operation of the pushing member 9b. Further, by pushing the pushing member 9b into the bottom surface 9a1 of the annular recess 9a while the chamfered portion 9b1 and the annular recess 9a are engaged in the axial direction, the pushing member 9b and the annular recess 9a, and thus the torch body 2 and the holder 6' of the gas lens 6, are more firmly fixed.

[0045] In the present embodiment, the pushing member 9b is a male screw and is screwed into a female screw hole 9c that penetrates the torch body 2 in the radial direction. In this case, since the male screw as the pushing member 9b is in a state where it can be operated from the outside, by connecting an operating tool to the operation hole 9b2 of the pushing member 9b and performing an axial rotation operation, the pushing member 9b can be easily advanced inward in the radial direction or retracted outward in the radial direction.

[0046] Further, in the present embodiment, as shown in FIG. 3, a mark 9d is provided on the outer peripheral surface of the portion of the narrowing nozzle 8 that protrudes beyond the shield nozzle 7 on the tip side. This mark 9d indicates the phase of the constriction nozzle 8, precisely, the orientation (circumferential position) of the gas rectifying groove 8d in the constriction nozzle 8. In this embodiment, among the outer peripheral surface of the constriction nozzle 8, the mark 9d is provided on the extension line of the virtual axis orthogonal to the opposing direction of the two gas rectifying grooves 8d (refer to FIG. 4).

[0047] The TIG welding torch 1 with the above configuration is used, for example, by being attached to the welding equipment 100 shown in FIG. 6. This welding equipment 100 is for performing butt welding of strip-shaped metal thin plates W1, W2 (refer to FIG. 7 described later), and includes a table 101 for setting these strip-shaped metal thin plates W1, W2, and a movable frame 102 that slidably supports the TIG welding torch 1 along a predetermined direction Y along the horizontal direction.

[0048] When the strip-shaped metal thin plates W1, W2 to be butt-welded are positioned and held (set) at a predetermined position on the table 101, as shown in FIG. 7, the butting surface Wa of the strip-shaped metal thin plates W1, W2 is set in the direction along the moving direction (welding direction) Y of the TIG welding torch 1. Also, the central position of the TIG welding torch 1 is set on the extension line of the butting surface Wa.

[0049] At this time, for example, as shown in FIG. 7, when the mark 9d is not on the extension line of the welding direction Y, the constriction nozzle 8 is rotated about its axis in the state where the pushing member 9b is retracted so that the mark 9d coincides with the extension line of the welding direction Y. In the case of the illustrated example, the constriction nozzle 8 is rotated about its axis (in the direction indicated by the arrow in FIG. 7) so that the mark 9d overlaps with the butting surface Wa in the circumferential direction.

[0050] While aligning the narrow nozzle 8 in this way and, if necessary, rotating the collet handle 5 to adjust the distance between the tip of the tungsten electrode rod 3 and the strip-shaped metal thin plates W1, W2), while flowing a shielding gas G such as argon gas from the shielding nozzle 7 and the narrow nozzle 8 of the TIG welding torch 1 toward the strip-shaped metal thin plates W1, W2), an electric power source (not shown) is operated to apply a predetermined voltage between the tungsten electrode rod 3 and the strip-shaped metal thin plates W1, W2) to generate an arc between the tip of the tungsten electrode rod 3 and the strip-shaped metal thin plates W1, W2) in the atmosphere of the shielding gas G.

[0051] The shielding gas G supplied into the torch body 2 flows down through the gas passage 6a of the holder 6' of the gas lens 6, and a part of it flows into the annular gas chamber 6f from the plurality of gas flow holes 6g, and the rest flows into the high-speed gas passage 8a of the narrow nozzle 8 from the gas passage 6a.

[0052] The shielding gas G flowing into the annular gas chamber 6f passes through the filter 6″ and is uniformly diffused to become a laminar flow gas and is discharged from the shielding nozzle 7 around the arc. Also, the shielding gas G flowing into the high-speed gas passage 8a increases its speed to become a high-speed gas and is rectified by passing through the gas rectifying groove 8d to become a high-speed rectified gas and is linearly discharged from the tip opening of the nozzle body 8b around the arc.

[0053] Note that since the positioning protrusion 8c and the gas rectifying groove 8d are formed at positions away from the tip of the nozzle body 8b, the high-speed rectified gas passing through the gas rectifying groove 8d is stabilized at the downstream portion of the high-speed gas passage 8a and is discharged from the tip opening of the nozzle body 8b in a stable state.

[0054] Then, since the arc generated between the tip of the tungsten electrode rod 3 and the strip-shaped metal thin plates W1 and W2 spreads from the tungsten electrode rod 3 toward the strip-shaped metal thin plates W1 and W2 (illustration omitted), the internal pressure of the arc is relatively high on the side of the tungsten electrode rod 3. As a result, a part of the shielding gas G is drawn into the arc, generating a high-speed gas flow called a plasma air current. This plasma air current greatly affects the fusion formation of the strip-shaped metal thin plates W1 and W2, and also affects the directivity and stiffness of the arc (the property of the arc to maintain its shape). The higher the speed of the plasma air current, the higher the directivity and stiffness of the arc can be enhanced.

[0055] In addition, the generated arc is constricted by the thermal pinch effect of the high-speed rectified gas discharged from the constriction nozzle 8 to form a stable arc with a high energy density.

[0056] After a stable arc is generated, the TIG welding torch 1 is moved along the butting surface Wa of the strip-shaped metal thin plates W1 and W2 at a predetermined speed. Thereby, the vicinity of the butting surface Wa of the strip-shaped metal thin plates W1 and W2 is melted by the heat of the arc generated between the tip of the tungsten electrode rod 3 and the strip-shaped metal thin plates W1 and W2, and the strip-shaped metal thin plates W1 and W2 are joined to each other.

[0057] The TIG welding torch 1 using the above-described constriction nozzle 8 is configured such that a part of the shielding gas G is made into a high-speed rectified gas faster than the laminarized shielding gas G discharged from the shielding nozzle 7 by the constriction nozzle 8, and this high-speed rectified gas is caused to flow around the arc. Therefore, the speed of the plasma air current flowing from the tungsten electrode rod 3 side toward the strip-shaped metal thin plates W1 and W2 side, which are the objects to be welded, reaches 2 to 3 times the conventional speed. In addition, the magnetic field and the electromagnetic force in the central axis direction acting on the arc are strengthened, and the energy density, directivity, and stiffness of the arc can be increased respectively, and a stable arc can be obtained.

[0058] As a result, by using the TIG welding torch 1 according to the above configuration, the welding speed can be increased to 5 to 20 times the conventional welding speed, enabling high-speed welding. Moreover, the bead width is uniform on both the front and back surfaces, and the intervals between the bead waveforms are formed at equal intervals, allowing for high-quality and stable welding.

[0059] In addition, this TIG welding torch 1 has a configuration in which two positioning ridges 8c, 8c and two gas rectifying grooves 8d, 8d are alternately arranged in the circumferential direction at 90° intervals on the inner circumference of the nozzle body 8b of the narrow nozzle 8. Therefore, a large amount of high-speed rectified gas can be flowed from the tip of the nozzle body 8b to opposite positions around the arc, and a small amount of high-speed rectified gas can be flowed to other locations.

[0060] In this case, since strong and weak portions of the plasma air flow are alternately formed every 90° in the circumferential direction of the arc, an arc having an elliptical cross-sectional shape and a high energy density can be formed. Thus, when an arc having an elliptical cross-sectional shape is formed, the preheating effect is enhanced, the penetration becomes larger, and the back wave is also likely to occur. Moreover, good welding can be performed even when the current is increased.

[0061] As described above, according to the TIG welding torch 1 according to the present embodiment, the phase adjustment mechanism 9 can adjust the phase of the constriction nozzle 8 with respect to the torch body 2 while the constriction nozzle 8 is held at a predetermined axial position with respect to the torch body 2. Therefore, even after the constriction nozzle 8 is attached to the torch body 2, and further, as shown in FIG. 6, even when the TIG welding torch 1 formed by attaching the constriction nozzle 8 to the torch body 2 is set in the welding equipment 100, the phase of the constriction nozzle 8 with respect to the torch body 2 can be appropriately changed. Here, since the directions (circumferential positions) of the two gas rectifying grooves 8d, 8d are always constant with respect to the constriction nozzle 8, it is possible to freely change the direction of the gas rectifying groove 8d by adjusting the phase of the constriction nozzle 8. Therefore, at any time, the direction of the gas rectifying groove 8d can be adjusted to match the welding direction Y (the moving direction of the TIG welding torch 1), and the TIG welding torch 1 can be used with high performance without being restricted in the usage mode.

[0062] Also, in the present embodiment, with the gas lens 6 to which the constriction nozzle 8 is fixed fitted to the torch body 2 so as to be axially rotatable, the phase adjustment mechanism 9 includes an annular recess 9a formed on the outer peripheral surface of the gas lens 6 to which the constriction nozzle 8 is fixed, and a pushing member 9b disposed at a position radially opposed to the annular recess 9a in the torch body 2 and movable in the radial direction and pushable into the bottom surface 9a1 of the annular recess 9a. Therefore, in a state where the pushing member 9b is pushed into the bottom surface 9a1 of the annular recess 9a, the phase of the constriction nozzle 8 with respect to the torch body 2 can be fixed. Further, by canceling the pushing state by the pushing member 9b, the constriction nozzle 8 can be axially rotated with respect to the torch body 2 to freely change the phase of the constriction nozzle 8. From the above, according to the TIG welding torch 1 according to this configuration, it is possible to adjust the direction of the gas rectifying groove 8d with a simple structure and a simple operation.

[0063] In addition, in the present embodiment, a female screw hole 9c penetrating the torch body 2 in the radial direction is formed at a position in the torch body 2 that is radially opposed to the annular recess 9a, and the pushing member 9b is a set screw that is screwed into the female screw hole 9c. Therefore, by an external operation, the pushing member 9b can be very easily moved in the radial direction, and the axially rotatable state and the restricted state of the constriction nozzle 8 can be easily switched. Thus, according to the TIG welding torch according to this configuration, it is possible to extremely easily perform the alignment of the constriction nozzle 8 and thus the adjustment of the direction of the gas rectifying groove 8d.

[0064] Furthermore, in the present embodiment, a mark 9d indicating the circumferential position of the gas rectifying groove 8d is provided on the outer peripheral surface of the portion of the constriction nozzle 8 that protrudes beyond the shield nozzle 7. Since the outer peripheral surface of the portion of the constriction nozzle 8 that protrudes beyond the shield nozzle 7 is always visible from the outside regardless of the viewing direction, by providing the mark 9d on the outer peripheral surface of this tip portion, the direction of the gas rectifying groove 9d can be easily confirmed regardless of the mounting mode of the TIG welding torch 1.

[0065] As described above, one embodiment of the present invention has been described. However, the TIG welding torch according to the present invention is not limited to the above-exemplified configuration, and it goes without saying that various modifications are possible within the scope of the present invention.

[0066] For example, in the above embodiment, the case where the mark 9d indicating the circumferential position of the gas rectifying groove 8d is provided on the tip outer peripheral surface of the constriction nozzle 8 has been exemplified. However, of course, it is not limited to this. For example, when the constriction nozzle 8 is fixed at a predetermined circumferential position with respect to the gas lens 6 and the shield nozzle 7 is fixed at a predetermined circumferential position with respect to the gas lens 6, a mark 9d indicating the circumferential position of the gas rectifying groove 8d may be provided on the outer peripheral surface of the shield nozzle 7 (see FIG. 8).

[0067] As described above, when the phase in the fixed state of the constriction nozzle 8 with respect to the shield nozzle 7 is known in advance, a mark 9d indicating the circumferential position of the gas rectifying groove 8d can also be provided on the outer peripheral surface of the shield nozzle 7. In this case, since the mark 9d is easier to check than the case where the mark 9d is provided at the tip portion of the constriction nozzle 8 (FIG. 3), it becomes possible to adjust the direction of the gas rectifying groove 8d more simply.

[0068] In the above-described embodiment, the case where the TIG welding torch according to the present invention is used in the welding equipment 100 for performing butt welding of the strip-shaped metal thin plates W1 and W2 (see FIG. 7 described later) is illustrated. However, of course, the present invention is not limited to this. As long as TIG welding is performed by moving the TIG welding torch along a predetermined direction, the TIG welding torch according to the present invention can be applied to any form of welding equipment.

Explanation of Reference Numerals

[0069] 1 TIG welding torch 2 Torch body 3 Tungsten electrode rod 4 Electrode collet 5 Collet handle 6 Gas lens 6′ Holder 6″ Filter 7 Shield nozzle 8 Constriction nozzle 8b Nozzle body 8c Positioning protrusion 8d Gas rectifying groove 9 Phase adjustment mechanism 9a Annular recess 9b Pushing member 9c Female screw hole 9d Mark G Shield gas W1, W2 Strip-shaped metal thin plates Y Welding direction (Moving direction of the TIG welding torch)

Claims

1. A torch body, A gas lens disposed in the internal space of the torch body and capable of laminarizing the shielding gas flowing into the internal space, A cylindrical shielding nozzle disposed on the tip side of the torch body with respect to the gas lens, A tungsten electrode rod disposed at the center position of the shielding nozzle, A constriction nozzle disposed between the shielding nozzle and the tip of the tungsten electrode rod, The constriction nozzle includes a cylindrical nozzle body that forms an annular high-speed gas passage between the outer peripheral surface of the tip of the tungsten electrode rod, Two positioning ridges disposed opposite to the inner peripheral surface of the nozzle body and holding the tungsten electrode rod at the center position of the nozzle body, In a TIG welding torch having two gas rectifying grooves that are alternately arranged in the circumferential direction of the two positioning ridges and the nozzle body and capable of rectifying the shielding gas flowing in the high-speed gas passage, The TIG welding torch further includes a phase adjustment mechanism capable of adjusting the phase of the constriction nozzle with respect to the torch body in a state where the constriction nozzle is held at a predetermined axial position with respect to the torch body.

2. The phase adjustment mechanism includes an annular recess formed on the outer peripheral surface of the constriction nozzle or the outer peripheral surface of the gas lens to which the constriction nozzle is fixed, An insertion member disposed at a position radially opposed to the annular recess among the torch body and the shielding nozzle, movable in the radial direction and capable of being pushed into the bottom surface of the annular recess, The TIG welding torch according to claim 1, wherein the constriction nozzle or the gas lens fixed to the constriction nozzle is fitted to the torch body so as to be rotatable about the axis.

3. The TIG welding torch according to claim 2, wherein the insertion member and the annular recess are engaged in the axial direction in a state where the insertion member is pushed into the bottom surface of the annular recess.

4. The constriction nozzle is fixed to the gas lens, the shielding nozzle is fixed to the gas lens, The annular recess is provided on the outer peripheral surface of the gas lens, The TIG welding torch according to claim 2 or 3, wherein the insertion member is a male screw threadedly fitted into a female screw hole penetrating the torch body in the radial direction.

5. The TIG welding torch according to claim 1, wherein a mark indicating the circumferential position of the gas rectifying groove is provided on the outer peripheral surface of a portion of the constricted nozzle that protrudes beyond the shield nozzle at the tip side.

6. The constricted nozzle is fixed to the gas lens at a predetermined circumferential position, and the shield nozzle is fixed to the gas lens at a predetermined circumferential position. The TIG welding torch according to claim 1, wherein a mark indicating the circumferential position of the gas rectifying groove is provided on the outer peripheral surface of the shield nozzle.

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