JP7769403B2 - TIG welding torch - Google Patents

Description

The present invention relates to a TIG welding torch.

TIG welding is known as a versatile welding technique that can be used with any material. This welding method is performed using a welding torch with an electrode made of tungsten, which has an extremely high melting point. By covering the welding area with a shielding gas made of an inert gas, the workpiece can be melted, which has the advantage of preventing oxygen in the air from reacting with the molten metal and ensuring good welding quality over the long term.

Here, known examples of TIG welding torches used in TIG welding include a TIG welding torch equipped with a cylindrical shield nozzle for discharging 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).

Among these, a TIG welding torch equipped with both a shield nozzle and a constriction nozzle allows shielding gas to be concentrated around the arc from the constriction nozzle, thereby increasing the arc energy density compared to a TIG welding torch equipped with only a shield nozzle. This allows for faster welding speeds and better arc directionality, but on the other hand, the range over which the shielding gas is released is narrowed, weakening the shielding effect and reducing the quality of the weld.

Furthermore, when replacing the tungsten electrode rod, it was difficult to set it back in its original position (the center of the constriction nozzle), resulting in poor reproducibility and workability.

The present applicant has therefore proposed a constriction nozzle for TIG welding designed to solve the above-mentioned 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, multiple positioning ridges that protrude from the inner peripheral surface of the nozzle body and hold the tungsten electrode rod in a central position on the nozzle body, and multiple gas rectification grooves that are formed between the multiple positioning ridges, extend parallel to the longitudinal direction of the nozzle body, and are capable of rectifying the shielding gas flowing within the high-velocity gas passage.

Patent No. 3163559 Patent No. 4327153 International Publication No. 2013/157036

By using a constricting nozzle with gas straightening grooves as described above, a portion of the shielding gas can be converted into high-speed straightened gas that flows faster than the laminar shielding gas released from between the shielding nozzle and the constricting nozzle, and this high-speed straightened gas can be flowed around the arc. This strengthens the electromagnetic and magnetic fields acting on the arc, increasing the arc's energy density, directionality, and rigidity, resulting in a stable arc. This significantly increases welding speeds compared to conventional methods, and also enables high-quality, stable welding with a uniform bead width on both sides and evenly spaced bead waveforms.

In addition, by forming multiple positioning ridges on the inner surface of the nozzle body that hold the tungsten electrode rod in the center of the nozzle body, the tungsten electrode rod can be accurately and reliably set in its original position (the center of the constricted nozzle) when replacing it, improving the reproducibility of the tungsten electrode rod installation position and improving workability.

In particular, by using a constriction nozzle with two positioning ridges and two gas straightening grooves alternately arranged around the circumference of the nozzle body, the arc generated between the base material (workpiece) can be narrowed into an elliptical shape. This further increases energy density. Furthermore, in the case of butt welding, narrowing 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 narrowed 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.

On the other hand, when performing TIG welding using a TIG welding torch equipped with a constriction nozzle of the above configuration, the mounting orientation of the constriction nozzle relative to the TIG welding torch becomes an issue. In other words, 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 secured 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 specified 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.

In light of the above, the technical problem to be solved by the present invention is to provide a TIG welding torch that allows the orientation of the gas rectifying groove relative to the torch body to be adjusted even when a constricted nozzle is attached to the torch body.

The above problems are solved by the TIG welding torch of the present invention. That is, this TIG welding torch includes a torch body, a gas lens disposed within 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 at the center of the shield nozzle, and a constriction nozzle disposed between the shield nozzle and the tip of the tungsten electrode rod. The constriction nozzle includes 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 the inner peripheral surface of the nozzle body and holding the tungsten electrode rod in the center position of the nozzle body, and two gas rectification grooves adjacent to each positioning ridge in the circumferential direction of the nozzle body and capable of rectifying the shielding gas flowing within the high-velocity gas passage. The TIG welding torch 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.

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, the phase of the constriction nozzle relative to the torch body can be appropriately changed 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 the welding equipment. Because the orientation (circumferential position) of the two gas rectification grooves is always constant relative to the constriction nozzle, adjusting the phase of the constriction nozzle makes it possible to freely change the orientation of the gas rectification grooves. 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 and with high performance.

In addition, 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 the outer peripheral surface of the gas lens to which the constriction nozzle is fixed, and a pusher member disposed in a position on the torch body or the shield nozzle radially opposite the annular recess, 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.

By configuring the phase adjustment mechanism in this way, the phase of the constriction nozzle relative to the torch body can be fixed when the pusher member is pressed into the bottom surface of the annular recess. Furthermore, by releasing the pressed-in state caused 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 a result, the TIG welding torch with this configuration makes it possible to adjust the orientation of the gas rectification groove with a simple structure and easy operation.

In this case, in the TIG welding torch according to the present invention, the push-in member and the annular recess may be axially engaged when the push-in member is pressed into the bottom surface of the annular recess.

By configuring the push-in member and the annular recess to engage axially in this way, the constricted nozzle can be more firmly fixed to the torch body so that it cannot rotate axially. This makes it possible to minimize the risk of the phase becoming misaligned due to unexpected contact after phasing, and to start TIG welding with the gas straightening grooves reliably oriented in the welding direction.

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 threaded into a female threaded hole that penetrates radially through the torch body.

With the constriction nozzle and 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 serving as a push-in member can be threaded into a female threaded hole that penetrates the torch body radially. This allows the set screw to be moved radially very easily from the outside, easily switching the constriction nozzle between an axially rotatable state and a restricted state. Therefore, with a TIG welding torch configured this way, it is extremely easy to align the phase of the constriction nozzle and thereby adjust the orientation of the gas straightening groove.

In addition, in the TIG welding torch according to the present invention, a mark indicating the circumferential position of the gas straightening groove may be provided on the outer peripheral surface of the portion of the constriction nozzle that protrudes further toward the tip than the shield nozzle.

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

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 straightening groove may be provided on the outer peripheral surface of the shield nozzle.

Furthermore, as mentioned above, if the phase of the constriction nozzle relative to the shield nozzle when fixed is known in advance, it is possible to provide a mark on the outer surface of the shield nozzle to indicate the circumferential position of the gas straightening groove. In this case, it is easier to identify the mark than if the mark were provided at the tip of the constriction nozzle, making it possible to adjust the orientation of the gas straightening groove more easily.

As described above, with the TIG welding torch of the present invention, it is possible to adjust the orientation of the gas straightening groove relative to the torch body even when a constricted nozzle is attached to the torch body.

1 is a cross-sectional view of a TIG welding torch according to an embodiment of the present invention. 2 is a side view of the TIG welding torch shown in FIG. 1 as viewed from the direction of arrow A. FIG. 3 is a front view of the TIG welding torch shown in FIG. 2 as viewed in the direction of arrow B. FIG. 2 is a cross-sectional view of the TIG welding torch shown in FIG. 1 taken along the line CC. FIG. 2 is an enlarged cross-sectional view of the phase adjustment mechanism shown in FIG. 1 . 2 is a perspective view of a welding facility to which the TIG welding torch shown in FIG. 1 is attached. FIG. 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. FIG. 10 is a front view of a TIG welding torch according to another embodiment of the present invention.

The following describes the TIG welding torch according to one embodiment of the present invention, with reference to the drawings.

1 is a cross-sectional view of a TIG welding torch 1 according to this embodiment, and FIGS. 2 and 3 are side and front views, respectively, of the TIG welding torch 1. This TIG welding torch 1 is primarily used for butt welding the ends of thin metal plates such as stainless steel sheets and electromagnetic steel sheets. It 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 threadedly inserted into the torch body 2 from above so as to be vertically movable and rotatable and detachably holds a tungsten electrode rod 3, a collet handle 5 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 detachably attached to the lower end of the torch body 2. It is composed of a gas lens 6 that is attached to the torch body 2 and homogenously diffuses the shielding gas G that flows in through the interior of the torch body 2, creating a laminar flow; a cylindrical shield nozzle 7 that is detachably attached to the gas lens 6 or to the torch body 2 and surrounds the tip of the tungsten electrode rod 3, and releases the shielding gas G that has been laminarized by the gas lens 6 around the arc; a constriction nozzle 8 that is arranged around the tip of the tungsten electrode rod 3 and flows a linear, high-speed rectified gas around the arc; and a phase adjustment mechanism 9 that can adjust the phase of the constriction nozzle relative to the torch body.

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

As shown in Figures 2 and 3, the torch body 2 consists of 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. An electrode/main gas pipe connector (neither shown) for connecting the main gas supply pipe and power cable, and a pressure adjustment screw 10 are inserted and fixed into the peripheral wall of the rectangular tube portion. Additionally, 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.

As shown in Figure 1, the electrode collet 4 is formed in a long, slender cylindrical shape with a split chuck portion at its tip. It is composed of a copper collet body 4' with a male threaded portion 4a formed on part of its outer surface that threads vertically into the female threaded portion 2a at the top end of the torch body 2, and a copper cylindrical fixture 4" that threads detachably onto the outer surface of the chuck portion of the collet body 4' and tightens the chuck 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 vertically within the torch body 2 by rotating the collet handle 5 fixed to the top end of the collet body 4'.

The gas lens 6 consists 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'.

Specifically, as shown in Figures 2 and 3, the holder 6' is cylindrical with a gas passage 6a formed in its center. 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 retaining tube 6c. The outer periphery is formed with a male thread 6b to which the shield nozzle 7 is detachably threaded, and a support tube 6e is located at the center of the retaining tube 6c. The inner periphery is formed with a female thread 6d 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 retaining tube 6c and the support tube 6e of the holder 6' forms an annular gas chamber 6f, which is connected to the interior of the torch body 2 via multiple gas passage holes 6g formed near the base end of the support tube 6e and the gas passage 6a of the holder 6'.

On the other hand, the filter 6" is formed by stacking multiple sheets of wire mesh punched into an annular shape, and is attached to the holder 6' by fitting its inner peripheral edge into the support tube 6e of the holder 6' and its outer peripheral edge into the holding tube 6c of the holder 6'.

As shown in Figures 1 to 3, the shield nozzle 7 is made of ceramic and shaped like a cylinder with a tapered tip. Part of its inner surface is formed with a female thread 7a that is detachably threaded onto the male thread 6b of the holding tube 6c of the gas lens 6. The shield nozzle 7 is attached to the outer surface of the gas lens 6 by threading the female thread 7a into the male thread 6b of the holding tube 6c of the gas lens 6. The shield nozzle 7 passes through the filter 6" of the gas lens 6 and emits laminarized shielding gas G around the tip of the tungsten electrode rod 3.

As shown in Figure 1, the constricting nozzle 8 is disposed around the tip of the tungsten electrode rod 3, forming an annular high-velocity gas passage 8a between it and the tip of the tungsten electrode rod 3. A portion 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 channeled into the high-velocity gas passage 8a, creating a high-velocity rectified gas that flows faster than the laminar shielding gas G flowing from the shield nozzle 7 around the constricting nozzle 8, and this high-velocity rectified gas is then allowed to flow around the arc.

That is, the constricting nozzle 8 is formed into a cylindrical body from copper (beryllium copper), which has excellent electrical conductivity and strength. As shown in Figures 1 and 4, it 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-velocity 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 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 around the circumference of the nozzle body 8b with the two positioning ridges 8c, 8c and that rectify the shielding gas G flowing within the high-velocity gas passage 8a.

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 Figure 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 Figure 4).

As described above, by arranging the two positioning ridges 8c, 8c and the two gas rectifying grooves 8d, 8d alternately at 90° intervals in the circumferential direction, it is possible to form an arc with an elliptical cross section, as described below. 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 Figure 4).

The positioning ridge 8c and gas rectifying groove 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 ridge 8c and gas rectifying groove 8d is larger than the inner diameter of the high-speed gas passage 8a located upstream of the positioning ridge 8c and gas rectifying groove 8d. As a result, the shielding gas G that flows into the high-speed gas passage 8a passes through the gas rectifying groove 8d and is rectified to become high-speed rectified gas. After stabilizing in the downstream portion of the high-speed gas passage 8a, it can be released from the tip opening of the nozzle body 8b.

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

The phase adjustment mechanism 9 allows the phase of the constriction nozzle 8 relative to the torch body 2 to be adjusted while the constriction nozzle 8 is held at a predetermined axial position relative to the torch body 2. In this embodiment, as shown in Figure 5, it comprises 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 pusher member 9b disposed on the torch body 2 at a position radially opposite the annular recess 9a, which is movable radially and can be pushed into the bottom surface 9a1 of the annular recess 9a.

Here, the upper end of the holder 6' for the gas lens 6, which is fixed to the constriction nozzle 8, is rotatably fitted around the inner periphery of the lower end of the torch body 2, as described above. Therefore, by retracting the pushing member 9b away from the annular recess 9a and rotating the gas constriction nozzle 8 or shield nozzle 7 around its axis, the phase of the constriction 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 axial movement of the holder 6' for the gas lens 6 relative to the torch body 2, and also restricts circumferential movement (axial rotation).

In addition, 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 pusher member 9b pushing operation, 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.

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

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 peripheral 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 FIG. 4).

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

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

At this time, if the mark 9d is not on the extension of the welding direction Y, as shown in Figure 7, for example, the constriction nozzle 8 is rotated axially with the pushing member 9b retracted so that the mark 9d is aligned with the extension of the welding direction Y, or in the illustrated example, so that the mark 9d overlaps the butt surface Wa in the circumferential direction (in the direction indicated by the arrow in Figure 7).

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, 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. A predetermined voltage is applied between the tungsten electrode rod 3 and the strip-shaped thin metal sheets W1, W2 by operating the power supply (not shown), generating an arc between the tip of the tungsten electrode rod 3 and the strip-shaped thin metal sheets W1, W2 in the shielding gas G atmosphere.

The shielding gas G supplied into the torch body 2 flows down the gas passage 6a of the holder 6' of the gas lens 6, with a portion of it flowing through multiple gas flow holes 6g into the annular gas chamber 6f, and the remainder flowing from the gas passage 6a into the high-velocity gas passage 8a of the constricted nozzle 8.

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

In addition, because the positioning ridge 8c and gas rectification groove 8d are formed away from the tip of the nozzle body 8b, the high-speed rectified gas that passes through the gas rectification groove 8d stabilizes in the downstream portion of the high-speed gas passage 8a and is released in a stable state from the tip opening of the nozzle body 8b.

The arc generated between the tip of the tungsten electrode rod 3 and the strip-shaped thin metal sheets W1, W2 spreads from the tungsten electrode rod 3 toward the strip-shaped thin metal sheets W1, W2 (not shown), so the internal pressure of the arc is relatively higher 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 flow. This plasma flow significantly affects the penetration of the strip-shaped thin metal sheets W1, W2 and also affects the directionality and rigidity of the arc (the ability of the arc to maintain its shape); the faster the speed, the greater the directionality and rigidity of the arc.

In addition, the generated arc is constricted by the thermal pinch effect of the high-speed rectified gas released from the constriction nozzle 8, resulting in a stable arc with high energy density.

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. This causes the heat of the arc generated between the tip of the tungsten electrode rod 3 and the strip-shaped thin metal sheets W1, W2 to melt the areas near the butt surface Wa of the strip-shaped thin metal sheets W1, W2, joining them to each other.

The TIG welding torch 1 using the constriction nozzle 8 described above converts a portion of the shielding gas G into a high-speed rectified gas that flows faster than the laminar shielding gas G emitted from the shield nozzle 7. This high-speed rectified gas is then caused to flow around the arc. As a result, the speed of the plasma airflow flowing from the tungsten electrode rod 3 toward the workpieces (the strip-shaped thin metal sheets W1 and W2) reaches two to three times the conventional speed. Furthermore, the magnetic field and electromagnetic force acting on the arc in the central axis direction are strengthened, increasing the energy density, directionality, and rigidity of the arc, resulting in a stable arc.

As a result, by using the TIG welding torch 1 configured as described above, the welding speed can be increased to 5 to 20 times faster than conventional welding speeds, enabling high-speed welding. Furthermore, the bead width is uniform on both the front and back, and the bead waveforms are evenly spaced, enabling stable, high-quality welding.

In addition, this TIG welding torch 1 is configured with two positioning ridges 8c, 8c and two gas rectifying grooves 8d, 8d arranged alternately at 90° intervals around the circumferential direction on the inner circumference of the nozzle body 8b of the constricted nozzle 8. This allows a larger amount of high-velocity rectified gas to flow 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.

In this case, areas of strong and weak plasma flow alternate every 90° around the circumference of the arc, creating an arc with an elliptical cross-section and high energy density. When an arc with an elliptical cross-section is created in this way, the preheating effect is improved, resulting in greater penetration and making it easier for back waves to form. Furthermore, good welding can be achieved even with increased current.

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. Because the orientation (circumferential position) of the two gas rectification grooves 8d, 8d is always constant relative to the constricting nozzle 8, adjusting the phase of the constricting nozzle 8 makes it possible to freely change the orientation of the gas rectification groove 8d. Therefore, the orientation of the gas rectification groove 8d can be aligned with the welding direction Y (the direction of movement of the TIG welding torch 1) at any time, enabling the TIG welding torch 1 to be used in a variety of applications with high performance.

In addition, in this embodiment, with the gas lens 6 to which the constriction nozzle 8 is fixed rotatably fitted 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 pusher member 9b disposed radially opposite the annular recess 9a on the torch body 2, movable radially, and capable of being pushed into the bottom surface 9a1 of the annular recess 9a. Therefore, when the pusher member 9b is 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 pusher member 9b, the constriction nozzle 8 can be rotated axially relative to the torch body 2, allowing the phase of the constriction nozzle 8 to be freely changed. As described above, the TIG welding torch 1 configured as described above enables the orientation of the gas rectifying groove 8d to be adjusted with a simple structure and easy operation.

In addition, in this embodiment, a female threaded hole 9c that penetrates the torch body 2 radially is formed in the torch body 2 at a position radially opposite the annular recess 9a, and the push-in member 9b is a set screw that is threadedly fitted into the female threaded hole 9c. This makes it extremely easy to move the push-in member 9b radially via external operation, easily switching the constriction nozzle 8 between an axially rotatable state and a restricted state. Therefore, with the TIG welding torch configured as described above, it becomes extremely easy to align the phase of the constriction nozzle 8 and thereby adjust the orientation of the gas rectifying groove 8d.

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 than the shield nozzle 7. The outer peripheral surface of the portion of the constricting nozzle 8 that protrudes further toward the tip 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 how the TIG welding torch 1 is attached.

The above describes one embodiment of the present invention, 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.

For example, in the above embodiment, a 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, but of course this is not limited to this. For example, if the constricting nozzle 8 is fixed at a predetermined circumferential position relative to the gas lens 6 and the shield nozzle 7 is fixed at a predetermined circumferential position relative 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 Figure 8).

As mentioned above, if the phase of the constricting nozzle 8 relative to the shield nozzle 7 when fixed is known in advance, a mark 9d indicating the circumferential position of the gas rectifying groove 8d can be provided on the outer surface of the shield nozzle 7. In this case, the mark 9d is easier to identify than when the mark 9d is provided at the tip of the constricting nozzle 8 (Figure 3), making it possible to more easily adjust the orientation of the gas rectifying groove 8d.

In addition, the above embodiment illustrates the use of a TIG welding torch according to the present invention in welding equipment 100 for butt welding strip-shaped thin metal sheets W1, W2 (see Figure 7 described below), but this is not necessarily limited to this. As long as TIG welding is performed by moving the TIG welding torch in a predetermined direction, the TIG welding torch according to the present invention can be applied to welding equipment of any type.

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 Narrowing nozzle 8b Nozzle body 8c Positioning protrusion 8d Gas rectifying groove 9 Phase adjustment mechanism 9a Annular recess 9b Push-in member 9c Female thread hole 9d Mark G Shield gas W1, W2 Strip-shaped thin metal plate Y Welding direction (movement direction of TIG welding torch)

Claims (6)

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. 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. A TIG welding torch as described in claim 2, wherein the pusher member and the annular recess engage axially when the pusher member is pushed into the bottom surface of the annular recess. 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. The TIG welding torch described in claim 1, wherein a mark indicating the circumferential position of the gas straightening groove is provided on the outer peripheral surface of the portion of the constriction nozzle that protrudes further toward the tip than the shield nozzle. 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.