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 TIG welding torch. [Background technology]

[0002] TIG welding is known as a versatile welding technique that can be used regardless of the material. This welding is performed using a welding torch with a tungsten electrode, which has an extremely high melting point. The welding area is surrounded by a shielding gas made of an inert gas, which allows the welded material to melt. This has the advantage of preventing oxygen in the air from reacting with the molten metal, thereby achieving good welding quality over the long term.

[0003] Here, known examples of TIG welding torches used in TIG welding include a TIG welding torch equipped with a cylindrical shield nozzle for discharging a shielding gas such as argon gas (see, for example, Patent Document 1), and a TIG welding torch equipped with the shield nozzle and a constriction nozzle for increasing the energy density of the arc (see, for example, Patent Document 2).

[0004] Among these, a TIG welding torch equipped with both a shield nozzle and a constriction nozzle can concentrate the flow of shielding gas from the constriction nozzle around the arc, thereby increasing the energy density of the arc compared to a TIG welding torch equipped with only a shield nozzle. This increases the welding speed and improves the directionality of the arc, but on the other hand, it narrows the range in which the shielding gas is released, weakening the shielding effect and reducing the quality of the weld.

[0005] Furthermore, when the tungsten electrode rod is replaced, it is difficult to set the tungsten electrode rod in its original position (the center position of the constricted nozzle), which causes problems such as poor reproducibility and workability.

[0006] Therefore, the present applicant has proposed a constriction nozzle for TIG welding aimed at solving the above problems (see Patent Document 3). This constriction nozzle is composed of a cylindrical nozzle body that is arranged around the tip of a tungsten electrode rod and forms an annular high-velocity gas passage between itself and the outer peripheral surface of the tip of the tungsten electrode rod, a plurality of positioning ridges that protrude from the inner peripheral surface of the nozzle body and hold the tungsten electrode rod in the center position of the nozzle body, and a plurality of gas rectification grooves that are formed between the plurality of positioning ridges, extend parallel to the longitudinal direction of the nozzle body, and are capable of rectifying the shielding gas flowing in the high-velocity gas passage. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 3163559 [Patent Document 2] Patent No. 4327153 [Patent Document 3] International Publication No. 2013 / 157036 Summary of the Invention [Problem to be solved by the invention]

[0008] By using a constricting nozzle with gas straightening grooves as described above, a portion of the shielding gas can be converted into high-velocity straightened gas that flows faster than the laminar shielding gas discharged from between the shielding nozzle and the constricting nozzle, and this high-velocity straightened gas can be made to flow around the arc. This strengthens the electromagnetic force and magnetic field acting on the arc, thereby increasing the energy density, directionality, and rigidity of the arc, thereby obtaining a stable arc. Therefore, the welding speed can be significantly increased compared to conventional methods, and the bead width can be uniform on both sides and the bead waveforms can be formed at equal intervals, resulting in high-quality, stable welding.

[0009] Furthermore, by forming a plurality of positioning ridges on the inner peripheral surface of the nozzle body to hold the tungsten electrode rod in the center position of the nozzle body, the tungsten electrode rod can be accurately and reliably set in its original position (the center position of the constricted nozzle) when replacing the tungsten electrode rod, improving the reproducibility of the attachment position of the tungsten electrode rod and improving workability.

[0010] In particular, by using a constriction nozzle with two positioning ridges and two gas straightening grooves alternately arranged in the circumferential direction of the nozzle body, the arc generated between the base material (workpiece) and the workpiece can be constricted into an elliptical shape. This further increases the energy density. Furthermore, in butt welding, constricting the arc into an elliptical shape enhances the preheating effect, increasing penetration and facilitating the production of back-beams. Furthermore, by aligning the major axis of the elliptical constriction of the arc with the welding direction, butt welding with a narrow bead width becomes possible. Therefore, even when welding materials that are not suitable for TIG welding, such as electrical steel sheets with insulating surfaces, using a TIG welding torch equipped with the constriction nozzle of the above configuration enables stable, high-quality, high-speed welding.

[0011] On the other hand, when performing TIG welding using a TIG welding torch equipped with the constriction nozzle of the above configuration, the mounting orientation of the constriction nozzle relative to the TIG welding torch becomes an issue. That is, to maximize the effectiveness of the constriction nozzle of the above configuration, the longitudinal axis of the elliptical arc must be aligned with the direction of movement of the TIG welding torch. However, in conventional TIG welding torches, the constriction nozzle and gas lens, and the gas lens and torch body, are both fixed by threaded engagement, and the mounting orientation of the constriction nozzle relative to the TIG welding torch (torch body) is not taken into consideration. Therefore, when welding is performed using a TIG welding torch mounted on welding equipment equipped with a mechanism for causing the TIG welding torch to perform a predetermined operation (e.g., a sliding movement), the orientation of the two gas rectifying grooves cannot be changed while the TIG welding torch is mounted on the welding equipment.

[0012] In view of the above circumstances, the present invention has as its technical problem to be solved, namely, to provide a TIG welding torch in which the orientation of the gas rectifying groove relative to the torch body can be adjusted even when a constricted nozzle is attached to the torch body. [Means for solving the problem]

[0013] The above-mentioned problems are solved by the 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 that has flowed into the internal space, a cylindrical shield nozzle disposed closer to the tip of the torch body than the gas lens, a tungsten electrode rod disposed in the center of the shield nozzle, and a constriction nozzle disposed between the shield nozzle and the tip of the tungsten electrode rod, wherein the constriction nozzle has a cylindrical nozzle body that forms an annular high-velocity gas passage between itself and 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 that hold the tungsten electrode rod in the center position of the nozzle body, and two gas rectification grooves that are adjacent to each positioning ridge in the circumferential direction of the nozzle body and are capable of rectifying the shielding gas flowing through the high-velocity gas passage, and is characterized in that it further includes a phase adjustment mechanism that can adjust the phase of the constriction nozzle relative to the torch body while the constriction nozzle is held at a predetermined axial position relative to the torch body.

[0014] As described above, the TIG welding torch according to the present invention is provided with a phase adjustment mechanism that can adjust the phase of the constriction nozzle relative to the torch body while the constriction nozzle is held at a predetermined axial position relative 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 attached constriction nozzle is set in welding equipment, the phase of the constriction nozzle relative to the torch body can be appropriately changed. Here, the orientation (circumferential position) of the two gas rectification grooves is always constant relative to the constriction nozzle, so the orientation of the gas rectification grooves can be freely changed by adjusting the phase of the constriction nozzle. Therefore, the orientation of the gas rectification grooves can be aligned with the welding direction (the direction of movement of the TIG welding torch) at any time, enabling the TIG welding torch to be used in a variety of applications with high performance.

[0015] Furthermore, in the TIG welding torch according to the present invention, the phase adjustment mechanism may have an annular recess formed on the outer peripheral surface of the constriction nozzle or on the outer peripheral surface of the gas lens to which the constriction nozzle is fixed, and a pushing member disposed in a position radially opposite the annular recess in the torch body or the shield nozzle, movable radially and capable of being pushed into the bottom surface of the annular recess, and the constriction nozzle or the gas lens fixed to the constriction nozzle may be fitted to the torch body so as to be rotatable about its axis.

[0016] By configuring the phase adjustment mechanism in this manner, the phase of the constriction nozzle relative to the torch body can be fixed when the pusher member is pushed into the bottom surface of the annular recess. Furthermore, by releasing the pushed-in state by the pusher member, the constriction nozzle can be rotated about its axis relative to the torch body, allowing the phase of the constriction nozzle to be freely changed. As described above, the TIG welding torch having this configuration allows the orientation of the gas rectifying groove to be adjusted with a simple structure and simple operation.

[0017] In this case, in the TIG welding torch according to the present invention, the push-in member and the annular recess may be engaged in the axial direction with the push-in member pressed into the bottom surface of the annular recess.

[0018] By configuring the push-in member and the annular recess to engage in the axial direction in this manner, the constricted nozzle can be more firmly fixed to the torch body so that it cannot rotate about its axis. Therefore, after phasing, it is possible to prevent as much as possible the situation where the phase is shifted due to unexpected contact or the like, and it is possible to start TIG welding with the gas rectifying grooves reliably oriented in accordance with the welding direction.

[0019] Furthermore, when the phase adjustment mechanism has an annular recess and a push-in 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 push-in member may be a set screw that is threadedly fitted into a female threaded hole that radially penetrates the torch body.

[0020] With the constriction nozzle and shield nozzle fixed to the gas lens in this manner, an annular recess is provided on the outer peripheral surface of the gas lens, and a set screw serving as a push-in member can be threadably fitted into an internally threaded hole that penetrates the torch body in the radial direction. This allows the set screw to be moved radially very easily from the outside, easily switching between an axially rotatable state of the constriction nozzle and an axially restricted state. Therefore, with the TIG welding torch having this configuration, it becomes very easy to align the phase of the constriction nozzle and thereby adjust the orientation of the gas rectifying groove.

[0021] 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 a portion of the constriction nozzle that protrudes further to the tip side than the shield nozzle.

[0022] The orientation (circumferential position) of the gas rectification grooves relative to the torch body can be seen from the opening side of the constricting nozzle, but depending on the mounting mode of the TIG welding torch, it may be difficult to see from the opening side of the constricting nozzle. In this regard, the outer circumferential surface of the portion of the constricting nozzle that protrudes further toward the tip side than the shield nozzle is always visible from the outside regardless of the viewing direction, so by providing a mark on the outer circumferential surface of this tip portion, the orientation of the gas rectification grooves can be easily confirmed.

[0023] Alternatively, in the TIG welding torch according to the present invention, the constriction nozzle may be fixed at a predetermined circumferential position relative to the gas lens, and the shield nozzle may be fixed at a predetermined circumferential position relative to the gas lens, 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] Furthermore, as described above, if the phase of the constricting nozzle relative to the shield nozzle in the fixed state is known in advance, it is also possible to provide marks on the outer circumferential surface of the shield nozzle to indicate the circumferential positions of the gas rectifying grooves. In this case, since the marks are easier to identify than when marks are provided at the tip portion of the constricting nozzle, it becomes possible to adjust the orientation of the gas rectifying grooves more easily. [Effects of the Invention]

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

[0026] [Figure 1] 1 is a cross-sectional view of a TIG welding torch according to an embodiment of the present invention. [Figure 2] 2 is a side view of the TIG welding torch shown in FIG. 1 as viewed from the direction of arrow A. FIG. [Figure 3] 3 is a front view of the TIG welding torch shown in FIG. 2 as viewed in the direction of arrow B. FIG. [Figure 4]2 is a cross-sectional view taken along CC of the TIG welding torch shown in FIG. 1. [Figure 5] FIG. 2 is an enlarged cross-sectional view of the phase adjustment mechanism shown in FIG. [Figure 6] FIG. 2 is a perspective view of a welding facility to which the TIG welding torch shown in FIG. 1 is attached. [Figure 7] 2 is a cross-sectional view of a main part showing an example of a phase adjustment mode by a phase adjustment mechanism of the TIG welding torch shown in FIG. 1. FIG. [Figure 8] FIG. 10 is a front view of a TIG welding torch according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0027] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A TIG welding torch according to an embodiment of the present invention will now be described with reference to the accompanying drawings.

[0028] 1 is a cross-sectional view of a TIG welding torch 1 according to this embodiment, and FIGS. 2 and 3 are a side view and a front view, respectively, of the TIG welding torch 1. This TIG welding torch 1 is used primarily for butt welding the ends of thin metal plates such as stainless steel plates and electromagnetic steel plates, and comprises 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 into the torch body 2 from above so as to be vertically movable and rotatable and that detachably holds a tungsten electrode rod 3, a collet handle 5 that is attached to the upper end of the electrode collet 4 and rotates the electrode collet 4 forward and backward to move it up and down relative to the torch body 2, and a collet handle 5 that is detachably attached to the lower end of the torch body 2. The shielding gas G is laminarized by diffusing it homogeneously through the gas lens 6, which is attached to the torch body 2 and surrounds the tip of the tungsten electrode rod 3. The shielding gas G is laminarized by the gas lens 6 and is detachably attached to the gas lens 6 or the torch body 2. The shielding gas G is laminarized by the gas lens 6 and is discharged around the arc. The constriction nozzle 8 is disposed around the tip of the tungsten electrode rod 3 and discharges a linear high-speed rectified gas around the arc. The phase adjustment mechanism 9 can adjust the phase of the constriction nozzle relative to the torch body.

[0029] In Figures 1 and 2, reference numeral 10 denotes a pressure adjustment screw provided on torch body 2 that applies an appropriate rotational resistance to electrode collet 4 to hold it in an adjusted position, 11 denotes an O-ring that seals the gap between torch body 2 and collet handle 5, and 12 denotes a plastic adjustment ring interposed between torch body 2 and shield nozzle 7.

[0030] 2 and 3, the torch body 2 comprises a rectangular tube portion made of a metal material such as aluminum alloy and a cylindrical portion connected to the upper end of the rectangular tube portion, and an electrode / main gas pipe connector (neither of which are shown) for connecting a main gas supply pipe and a power cable, and a pressure adjustment screw 10 are inserted and fixed into the peripheral wall of the rectangular tube portion. Also, a female thread portion 2a is formed on the inner peripheral surface of the upper end opening of the torch body 2, into which an electrode collet 4 holding a tungsten electrode rod 3 is threaded so as to be movable up and down.

[0031] As shown in FIG. 1, the electrode collet 4 is formed in the shape of a long, thin cylinder with a split chuck portion at its tip. The electrode collet 4 comprises a copper collet body 4' having a male threaded portion 4a formed on part of its outer surface that is threadedly attached to the female threaded portion 2a at the upper end of the torch body 2 so as to be freely movable up and down, and a copper cylindrical fixture 4" that is detachably threaded onto the outer surface of the chuck portion of the collet body 4' and tightens the chuck portion to secure the tungsten electrode rod 3 inserted into the collet body 4'. The electrode collet 4 is threaded into the torch body 2 from above, and can be moved up and down within the torch body 2 by rotating a collet handle 5 fixed to the upper end of the collet body 4'.

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

[0033] Specifically, as shown in Figures 2 and 3, the holder 6' is formed as a cylindrical body with a gas passage 6a formed in its center, and the upper end of the holder 6' is rotatably fitted (loose fit) to the inner periphery of the lower end of the torch body 2. The lower end of the holder 6' is also formed with a cylindrical holding cylinder 6c. The outer periphery of the holding cylinder 6c has a male thread 6b formed therein, to which the shield nozzle 7 is detachably threaded. The support cylinder 6e is located at the center of the holding cylinder 6c and has a female thread 6d formed therein, to which the constriction nozzle 8 is detachably threaded. This allows both the shield nozzle 7 and the constriction nozzle 8 to be fixed to the gas lens 6 by threaded engagement. Furthermore, the space between the holding cylinder 6c and the support cylinder 6e of the holder 6' forms an annular gas chamber 6f, which is connected to the inside of the torch body 2 via multiple gas passage holes 6g formed near the base end of the support cylinder 6e and the gas passages 6a of the holder 6'.

[0034] On the other hand, the filter 6" is formed by laminating multiple sheets of wire mesh punched into annular shapes, and is attached to the holder 6' by fitting its inner peripheral edge into the support cylinder 6e of the holder 6' and its outer peripheral edge into the holding cylinder 6c of the holder 6'.

[0035] As shown in Figures 1 to 3, the shield nozzle 7 is made of ceramic and formed into a cylindrical shape with a tapered tip, and a female threaded portion 7a is formed on part of its inner peripheral surface so as to be detachably threaded onto the male threaded portion 6b of the holding cylindrical portion 6c of the gas lens 6. The shield nozzle 7 is attached to the outer peripheral surface of the gas lens 6 by threading the female threaded portion 7a onto the male threaded portion 6b of the holding cylindrical portion 6c of the gas lens 6, and is designed to emit the shielding gas G, which has passed through the filter 6" of the gas lens 6 and has been made into a laminar flow, around the tip of the tungsten electrode rod 3.

[0036] As shown in FIG. 1, the constricting nozzle 8 is disposed around the tip of the tungsten electrode rod 3 to form an annular high-velocity gas passage 8a between itself and the tip of the tungsten electrode rod 3. A portion of the shielding gas G flowing from the inside of 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-velocity gas passage 8a, becoming a high-velocity rectified gas that flows faster than the laminar flow of the shielding gas G flowing from the shield nozzle 7 around the constricting nozzle 8, and this high-velocity rectified gas is made to flow around the arc.

[0037] That is, the constricting nozzle 8 is formed into a cylindrical body from a copper material (beryllium copper) having excellent electrical conductivity and strength, and as shown in FIGS. 1 and 4, the constricting nozzle 8 has a cylindrical nozzle body 8b that is arranged concentrically with the tungsten electrode rod 3 around the tip of the tungsten electrode rod 3 and forms an annular high-speed gas passage 8a between itself 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 in the center position of the nozzle body 8b, and two gas rectifying grooves 8d, 8d that are arranged alternately with the two positioning ridges 8c, 8c in the circumferential direction of the nozzle body 8b and can rectify the shielding gas G flowing within 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 rectification groove 8d also extends along the longitudinal direction of the nozzle body 8b (see FIG. 1). In this embodiment, the side surface 8c1 of each positioning ridge 8c is flat and extends linearly in a direction perpendicular to the opposing direction of the two gas rectification grooves 8d, 8d (see FIG. 4).

[0039] As described above, by providing two positioning ridges 8c and two gas rectifying grooves 8d alternately at 90° intervals in the circumferential direction, an arc with an elliptical cross section can be formed, as will be described later. In this case, 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 ridges 8c and gas rectifying grooves 8d in the above configuration are formed at a position above and away from the tip of the nozzle body 8b, and the inner diameter of the high-speed gas passage 8a located downstream of the positioning ridges 8c and gas rectifying grooves 8d is larger than the inner diameter of the high-speed gas passage 8a located upstream of the positioning ridges 8c and gas rectifying grooves 8d. As a result, the shielding gas G that has flowed into the high-speed gas passage 8a passes through the gas rectifying grooves 8d and is rectified to become a high-speed rectified gas, which is stabilized in the downstream portion of the high-speed gas passage 8a before being released from the tip opening of the nozzle body 8b.

[0041] The tip end (lower end) of nozzle body 8b is tapered, and the outer peripheral surface of the base end (upper end) of nozzle body 8b is formed with a male thread portion 8e that is detachably screwed into support cylinder portion 6e of holder 6' of gas lens 6. Therefore, by screwing this male thread portion 8e into support cylinder portion 6e, constricting nozzle 8 is attached to the center of the tip face of gas lens 6.

[0042] The phase adjustment mechanism 9 is capable of adjusting the phase of the constriction nozzle 8 relative to the torch body 2 while the constriction nozzle 8 is held at a predetermined axial position relative to the torch body 2. In this embodiment, as shown in FIG. 5 , the phase adjustment mechanism 9 has 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 constriction nozzle 8 is fixed, and a push-in member 9b disposed on the torch body 2 at a position radially opposite to the annular recess 9a, which is movable radially, and which can be pushed into the bottom surface 9a1 of the annular recess 9a.

[0043] Here, as described above, the upper end of the holder 6' of the gas lens 6 fixed to the constricting nozzle 8 is rotatably fitted to the inner periphery of the lower end of the torch body 2. Therefore, by axially rotating the constricting nozzle 8 or the shield nozzle 7 while the pushing member 9b is retracted away from the annular recess 9a, the phase of the constricting nozzle 8 relative to the torch body 2 can be changed. Furthermore, when the pushing member 9b is pressed into the bottom surface 9a1 of the annular recess 9a as shown in Figure 5, the pushing force of the pushing member 9b restricts the axial movement of the holder 6' of the gas lens 6 relative to the torch body 2 and also restricts its circumferential movement (axial rotation).

[0044] In this embodiment, a chamfered portion 9b1 is provided at the tip of the pusher member 9b. This chamfered portion 9b1 engages with the annular recess 9a in the axial direction during the pushing operation of the pusher member 9b, thereby guiding the holder 6' of the gas lens 6 to a predetermined axial position. Furthermore, by pushing the pusher 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 pusher member 9b and the annular recess 9a, and therefore the torch body 2 and the holder 6' of the gas lens 6, are more firmly fixed together.

[0045] In this embodiment, the pushing member 9b is a male screw that is threadedly fitted into a female screw hole 9c that penetrates radially through the torch body 2. In this case, the male screw of the pushing member 9b can be operated from the outside, so that by connecting an operating tool to the operating hole 9b2 of the pushing member 9b and operating it to rotate around its axis, the pushing member 9b can be easily advanced radially inward or retracted radially outward.

[0046] In this embodiment, as shown in FIG. 3, a mark 9d is provided on the outer peripheral surface of the portion of the constricting nozzle 8 that protrudes further toward the tip side than the shield nozzle 7. This mark 9d indicates the phase of the constricting nozzle 8, more precisely, the orientation (circumferential position) of the gas straightening grooves 8d in the constricting nozzle 8. In this embodiment, the mark 9d is provided on the outer surface of the constricting nozzle 8 on an extension of a virtual axis that is perpendicular to the opposing direction of the two gas straightening grooves 8d (see Figure 4).

[0047] The TIG welding torch 1 having the above configuration is used by being attached to, for example, welding equipment 100 shown in Fig. 6. This welding equipment 100 is used to butt-weld strip-shaped thin metal sheets W1, W2 (see Fig. 7 described later), and includes a table 101 for setting these strip-shaped thin metal sheets W1, W2, and a movable frame 102 that supports the TIG welding torch 1 so that it can slide along a predetermined direction Y that is horizontal.

[0048] When the strip-shaped metal sheets W1, W2 to be butt-welded are positioned and held (set) at predetermined positions on the table 101, the butt surfaces Wa of the strip-shaped metal sheets W1, W2 are set to be oriented along the movement direction (welding direction) Y of the TIG welding torch 1, as shown in Fig. 7. In addition, the center position of the TIG welding torch 1 is set on an extension of the butt surfaces Wa.

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

[0050] After aligning the phase of the constriction 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 thin metal sheets W1, W2, a shielding gas G such as argon gas is flowed from the shield nozzle 7 and constriction nozzle 8 of the TIG welding torch 1 toward the strip-shaped thin metal sheets W1, W2, while operating the power supply (not shown) to apply a predetermined voltage between the tungsten electrode rod 3 and the strip-shaped thin metal sheets W1, W2, generating an arc between the tip of the tungsten electrode rod 3 and the strip-shaped thin metal sheets W1, W2 in the atmosphere of 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 portion of it flows into the annular gas chamber 6f through the multiple gas circulation holes 6g, and the remainder flows from the gas passage 6a into the high-velocity gas passage 8a of the constricted nozzle 8.

[0052] The shielding gas G that flows into the annular gas chamber 6f passes through the filter 6" and is diffused homogeneously, becoming a laminar flow gas, which is then discharged from the shield nozzle 7 around the arc. Furthermore, the shielding gas G that flows into the high-velocity gas passage 8a increases in speed and becomes a high-velocity gas, and is rectified by passing through the gas rectifying grooves 8d, becoming a high-velocity rectified gas which is then discharged in a straight line around the arc from the tip opening of the nozzle body 8b.

[0053] Furthermore, since the positioning ridge 8c and the gas rectifying groove 8d are formed at a position away from the tip of the nozzle body 8b, the high-velocity rectified gas that has passed through the gas rectifying groove 8d is stabilized in the downstream portion of the high-velocity gas passage 8a and is released in a stable state from the tip opening of the nozzle body 8b.

[0054] The arc generated between the tip of the tungsten electrode rod 3 and the strip-shaped thin metal plates W1, W2 spreads from the tungsten electrode rod 3 toward the strip-shaped thin metal plates W1, W2 (not shown), so the internal pressure of the arc is relatively high on the tungsten electrode rod 3 side. As a result, part of the shielding gas G is drawn into the arc, generating a high-speed gas flow called a plasma airflow. This plasma airflow significantly affects the penetration of the strip-shaped thin metal plates W1, W2 and also affects the directionality and rigidity of the arc (the ability of the arc to maintain its shape). The faster the plasma airflow, the greater the directionality and rigidity of the arc.

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

[0056] After a stable arc is generated, the TIG welding torch 1 is moved at a predetermined speed along the butt surface Wa of the strip-shaped thin metal sheets W1, W2, whereby the heat of the arc generated between the tip of the tungsten electrode rod 3 and the strip-shaped thin metal sheets W1, W2 melts the vicinity of the butt surface Wa of the strip-shaped thin metal sheets W1, W2, and the strip-shaped thin metal sheets W1, W2 are joined together.

[0057] The TIG welding torch 1 using the above-mentioned constriction nozzle 8 converts part of the shielding gas G into a high-velocity rectified gas that flows faster than the laminar shielding gas G released from the shield nozzle 7, and this high-velocity rectified gas flows around the arc, so that the speed of the plasma airflow flowing from the tungsten electrode rod 3 toward the strip-shaped thin metal sheets W1 and W2 that are the workpieces reaches two to three times the conventional speed. In addition, the magnetic field and electromagnetic force in the central axis direction acting on the arc are strengthened, which increases the energy density, directionality, and rigidity of the arc, thereby obtaining a stable arc.

[0058] As a result, by using the TIG welding torch 1 having the above configuration, the welding speed can be increased to 5 to 20 times faster than conventional welding speeds, enabling high-speed welding. In addition, the bead width is uniform on both the front and back sides, and the bead waveforms are spaced at equal intervals, allowing for high-quality, stable welding.

[0059] Furthermore, this TIG welding torch 1 has two positioning ridges 8c and two gas rectifying grooves 8d arranged alternately at 90° intervals around the circumference of the nozzle body 8b of the constricted nozzle 8, so that it is possible to flow a large amount of high-velocity rectified gas from the tip of the nozzle body 8b to opposing positions around the arc and a smaller amount of high-velocity rectified gas to other locations.

[0060] In this case, strong and weak plasma flow alternate every 90° in the circumferential direction of the arc, resulting in an arc with an elliptical cross section and high energy density. When an arc with an elliptical cross section is formed in this way, the preheating effect is improved, resulting in greater penetration and easier generation of back waves. Furthermore, good welding can be achieved even with increased current.

[0061] As described above, with the TIG welding torch 1 according to this embodiment, the phase adjustment mechanism 9 can adjust the phase of the constricting nozzle 8 relative to the torch body 2 while the constricting nozzle 8 is held at a predetermined axial position relative to the torch body 2. Therefore, even after the constricting nozzle 8 is attached to the torch body 2, or even when the TIG welding torch 1 with the constricting nozzle 8 attached to the torch body 2 is set in welding equipment 100 as shown in FIG. 6 , the phase of the constricting nozzle 8 relative to the torch body 2 can be appropriately changed. Here, the orientation (circumferential position) of the two gas rectifying grooves 8d, 8d is always constant relative to the constricting nozzle 8, so the orientation of the gas rectifying groove 8d can be freely changed by adjusting the phase of the constricting nozzle 8. Therefore, the orientation of the gas rectifying groove 8d can be aligned with the welding direction Y (the direction of movement of the TIG welding torch 1) at any time, allowing the TIG welding torch 1 to be used in a variety of applications with high performance.

[0062] Furthermore, in this embodiment, with the gas lens 6 to which the constriction nozzle 8 is fixed fitted axially rotatably relative to the torch body 2, the phase adjustment mechanism 9 is composed of 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 push-in member 9b disposed in the torch body 2 at a position radially opposite the annular recess 9a, movable radially, and push-in capable of being pushed into the bottom surface 9a1 of the annular recess 9a. Therefore, with the push-in member 9b pushed into the bottom surface 9a1 of the annular recess 9a, the phase of the constriction nozzle 8 relative to the torch body 2 can be fixed. Furthermore, by releasing the pushed-in state by the push-in member 9b, the constriction nozzle 8 can be rotated axially relative to the torch body 2, thereby freely changing the phase of the constriction nozzle 8. As described above, the TIG welding torch 1 having this configuration makes it possible to adjust the orientation of the gas rectifying groove 8d with a simple structure and simple operation.

[0063] Furthermore, in this embodiment, a female threaded hole 9c that penetrates the torch body 2 in the radial direction is formed in the torch body 2 at a position radially opposite to the annular recess 9a, and the push-in member 9b is a set screw that is threadedly fitted into the female threaded hole 9c, so that the push-in member 9b can be very easily moved in the radial direction by an external operation, and the constricting nozzle 8 can be easily switched between an axially rotatable state and a restricted state. Therefore, with the TIG welding torch having this configuration, it is very easy to align the phase of the constricting nozzle 8 and thereby adjust the orientation of the gas rectifying grooves 8d.

[0064] Furthermore, in this 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 constricting nozzle 8 that protrudes further toward the tip side than the shield nozzle 7. The outer peripheral surface of the portion of the constricting nozzle 8 that protrudes further toward the tip side than the shield nozzle 7 is always visible from the outside regardless of the viewing direction, so by providing the mark 9d on the outer peripheral surface of this tip portion, the orientation of the gas rectifying groove 9d can be easily confirmed regardless of the mounting mode of the TIG welding torch 1.

[0065] An embodiment of the present invention has been described above, but the TIG welding torch according to the present invention is not limited to the above-described exemplary configuration, and 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 outer peripheral surface of the tip of the constricting nozzle 8 has been exemplified, but of course the present invention is not limited to this. For example, in a case where the constricting 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, the 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, if the phase of the constricting nozzle 8 in the fixed state relative to the shield nozzle 7 is known in advance, it is also possible to provide a mark 9d indicating the circumferential position of the gas rectifying grooves 8d on the outer circumferential surface of the shield nozzle 7. In this case, it is easier to check the mark 9d than when the mark 9d is provided at the tip portion of the constricting nozzle 8 (FIG. 3), and therefore it becomes possible to adjust the orientation of the gas rectifying grooves 8d more easily.

[0068] In the above embodiment, the TIG welding torch according to the present invention is used in welding equipment 100 for butt welding strip-shaped thin metal sheets W1, W2 (see FIG. 7 described later), but the present invention is not limited to this. As long as the TIG welding torch is moved in a predetermined direction to perform TIG welding, the TIG welding torch according to the present invention can be applied to any type of welding equipment. [Explanation of symbols]

[0069] 1 TIG welding torch 2 Torch body 3 tungsten electrodes 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 rectification groove 9 Phase adjustment mechanism 9a Annular recess 9b Push-in member 9c female thread hole 9d Landmark G Shielding gas W1, W2 Metal strips Y Welding direction (direction of movement of TIG welding torch)

Claims

1. Torch body and 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 shield nozzle disposed closer to the tip of the torch body than the gas lens; a tungsten electrode rod disposed at the center of the shield nozzle; a constriction nozzle disposed between the shield nozzle and the tip of the tungsten electrode rod, The constricting nozzle includes a cylindrical nozzle body that forms an annular high-speed gas passage between itself and the outer peripheral surface of the tip of the tungsten electrode rod; two positioning protrusions disposed opposite to each other on the inner circumferential surface of the nozzle body, for holding the tungsten electrode rod at a central position of the nozzle body; a TIG welding torch having the two positioning protrusions and two gas rectifying grooves arranged alternately in the circumferential direction of the nozzle body and capable of rectifying the shielding gas flowing through the high-velocity gas passage, 1. A TIG welding torch, further comprising: a phase adjustment mechanism that adjusts the phase of the constriction nozzle relative to the torch body while the constriction nozzle is held at a predetermined axial position relative to the torch body.

2. the phase adjustment mechanism includes an annular recess formed on an outer circumferential surface of the constriction nozzle or on an outer circumferential surface of the gas lens to which the constriction nozzle is fixed; a pusher member disposed in the torch body and the shield nozzle at a position radially opposite the annular recess, the pusher member being radially movable and capable of being pushed into the bottom surface of the annular recess, 2. 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 its axis.

3. 3. The TIG welding torch according to claim 2, wherein the pusher member and the annular recess engage in an axial direction when the pusher member is pushed into the bottom surface of the annular recess.

4. the constriction nozzle is fixed to the gas lens, and the shield nozzle is fixed to the gas lens; the annular recess is provided on the outer peripheral surface of the gas lens, 4. The TIG welding torch according to claim 2, wherein the pushing member is a male screw that is threadedly fitted into a female screw hole that passes radially through the torch body.

5. 2. The TIG welding torch according to claim 1, wherein a mark indicating a circumferential position of the gas rectifying groove is provided on an outer peripheral surface of a portion of the constricting nozzle that protrudes further toward the tip side than the shield nozzle.

6. the constriction nozzle is fixed at a predetermined circumferential position relative to the gas lens, and the shield nozzle is fixed at a predetermined circumferential position relative to the gas lens, 2. 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.

Images