JP7224657B2 - TIG welding torch with narrow nozzle for spot welding - Google Patents

Description

INDUSTRIAL APPLICABILITY The present invention is used for spot welding (tack welding) metal plates (base materials) such as stainless steel plates, steel plates, copper plates, and aluminum plates, and is particularly equipped with a non-consumable tank strap electrode. The present invention relates to a TIG welding torch with a constricted nozzle for spot welding, which is an improved TIG welding torch.

In general, spot welding (temporary welding) is used when two metal plates are temporarily attached, or when a joint between metal plates does not require a very high joint strength. For the shape of joints used for welding, lap joints, butt joints, corner joints, edge joints, T joints, and the like are used.

2. Description of the Related Art Conventionally, resistance welding has been widely used for spot welding of two metal plates. That is, in resistance welding, the parts to be welded of two metal plates are sandwiched between electrodes, an appropriate pressure is applied to the electrodes, and an electric current is applied to melt and bond the welded parts by Joule heat.

However, the resistance welding described above is not suitable for spot welding (tack welding) of metal plates such as copper plates and aluminum plates, which have low electrical resistance. Laser welding using laser light from a laser head), plasma welding using a plasma welding torch (see, for example, Patent Document 1), TIG welding using a TIG welding torch (see, for example, Patent Documents 2 and 3) is used.

However, spot welding of metal plates such as copper plates and aluminum plates with low electrical resistance by laser welding, plasma welding, or TIG welding poses the following problems.

That is, the two metal plates to be spot-welded must be pressure-bonded. This is because if there is a gap between the two metal plates, the arc heat will not be transmitted to both metal plates, resulting in imperfect bonding. It may not be possible to join metal plates. As a result, a holding jig is required to press the two metal plates into close contact with each other, resulting in poor workability.

In addition, it is necessary to keep the height (or position) of the laser beam emitting unit, plasma welding torch, or TIG welding torch constant with respect to the metal plates to be spot-welded. This is because if the height (or position) of the emission unit, plasma welding torch or TIG welding torch varies, the input heat density will not be constant, resulting in unstable penetration. Therefore, a jig is required to keep the height (or position) of the laser beam emitting unit, the plasma welding torch, or the TIG welding torch constant with respect to the metal plate, resulting in poor workability.

Furthermore, when spot welding is used to tack two metal plates by TIG welding using a TIG welding torch, butt joints, corner joints, edge joints, T joints, lap joints, etc. are used as joint shapes. However, in order to perform good spot welding, it is necessary to pay attention to the following points.
(1) The target position is determined so that the arc will surely transfer to the location to be spot-welded.
(2) Keep the distance between the tungsten electrode rod and the metal plate constant so that the arc length is constant.
(3) Prevent short circuit between the tungsten electrode rod and the metal plate.

However, in TIG welding using a TIG welding torch, operator experience is required in order to determine the target position of spot welding, keep the arc length constant, and prevent short circuits. There is a problem that good spot welding can be performed only by a skilled person because there are individual differences in welding.

In addition, when the tungsten electrode rod and the metal plate are short-circuited, the tip of the tungsten electrode rod is worn out, and the tungsten electrode rod must be polished, resulting in a problem of extremely poor workability.

On the other hand, as a TIG welding torch that solves the above-mentioned problems, a TIG welding torch with a narrow nozzle for spot welding previously developed by the present inventor (international application number: PCT / JP2019 / 050305) and a non-consumable TIG welding torch developed by another company A torch for arc spot welding (see, for example, Patent Document 4 (FIG. 3)) having a tungsten electrode rod of the following type is known.

That is, although not shown, the TIG welding torch with a narrow nozzle and the torch for arc spot welding have a conductive cylindrical electrode nozzle and a conductive cylindrical support member at the tip of the torch. Attached so as to surround the tip of the tungsten electrode rod, the target position for spot welding can be easily determined by pressing the conductive electrode nozzle or supporting member against the metal plate (base material) to be welded. In addition, the arc length can be kept constant.

Japanese Utility Model Laid-Open No. 61-182677 Japanese Patent No. 5602974 Japanese Patent No. 5887445 JP 2014-100734 A

However, even the TIG welding torch with a constricted nozzle and the arc spot welding torch described above still have problems to be solved.

That is, the TIG welding torch with a narrow nozzle and the torch for arc spot welding need to change the arc length according to the magnitude of the welding current. The tip of the electrode nozzle and the support member must be adjusted to a predetermined position, and a very troublesome work is required to set the position of the tungsten electrode rod to the predetermined position.

Another problem is that a setting gauge is required to set the position of the tungsten electrode rod to a predetermined position.

The present invention has been made in view of such problems, and its object is to adjust the position of the tungsten electrode rod to a predetermined position without using a setting gauge when changing the arc length according to the magnitude of the welding current. To provide a TIG welding torch with a constricted nozzle for spot welding which can be easily set to a point and can set the arc length by one touch.

In order to achieve the above object, a TIG welding torch with a narrow nozzle for spot welding according to the present invention holds a torch body and a tungsten electrode rod detachably inserted into the torch body and connected to a cathode, an electrode collet through which the shielding gas passes; an electrode collet provided at the tip of the electrode collet, supporting the tungsten electrode rod concentrically to form a gas passage through which the shielding gas flows between the tungsten electrode rod and the tungsten electrode rod; A constricted nozzle that ejects shielding gas toward the tip of the rod, a conductive cylindrical ground connection fitting that is provided at the tip of the torch body and is connected to the anode via the ground cable, and a ground connection fitting. is screwed to the outer peripheral surface of the tungsten electrode rod so that it can be moved and adjusted in the axial direction of the tungsten electrode rod, and the tip portion is formed in a tapered shape, and has conductivity surrounding the tip portion of the tungsten electrode rod protruding from the constriction nozzle. A cylindrical electrode nozzle is provided, and the pitch of the male screw formed on the outer peripheral surface of the ground connection fitting is the same as the pitch of the female screw formed on the inner peripheral surface of the electrode nozzle and screwed into the male screw. The reference position of the electrode nozzle is defined as a position where the tip of the tungsten electrode rod and the tip surface of the electrode nozzle are aligned with each other, and the outer peripheral surface of the ground connection fitting and the outer peripheral surface of the electrode nozzle are formed at a predetermined pitch. is provided with an arc length display unit for setting the arc length by displaying the amount of movement of the electrode nozzle from the reference position, the arc length display unit being the outer peripheral surface of the ground connection fitting or the outer peripheral surface of the electrode nozzle. and a scale indicating the amount of movement of the electrode nozzle from the reference position; The electrode nozzle is divided into upper and lower halves, and is screwed to the outer peripheral surface of the ground connection fitting so as to be movable and adjustable in the axial direction of the tungsten electrode rod. and a conductive cylindrical nozzle tip which is detachably provided at the tip of the nozzle body and which has a convergence at the tip , wherein the It is characterized in that the nozzle body and the nozzle tip are made of different conductive materials, and a gas vent is formed in the peripheral wall of the nozzle body to release the shielding gas in the electrode nozzle to the outside.

It is preferable to interpose an O-ring between the outer peripheral surface of the ground connection fitting and the inner peripheral surface of the electrode nozzle to provide a resistance to stop the rotation of the electrode nozzle.

It is preferable that a V-shaped positioning groove that is formed along the diameter direction of the nozzle tip and fitted to the corner of the corner joint is formed in the tip surface of the nozzle tip.

It is preferable that the outer peripheral surface of the tip of the nozzle tip is formed with a facing positioning surface that contacts the corner of the T-joint in a surface contact state.

The TIG welding torch with a constricted nozzle for spot welding according to the present invention has an electrode nozzle that contacts a metal plate to be spot-welded so that it can be moved and adjusted in the axial direction of the tungsten electrode rod, and the amount of movement of the electrode nozzle is adjusted. Equipped with an arc length display such as a scale to display, when changing the arc length according to the size of the welding current, all you have to do is rotate the electrode nozzle and look at the arc length display, eliminating the need for a setting gauge. As a result, the position of the tungsten electrode rod can be easily set at a predetermined position, and the arc length can be set with a single touch.

1 is a front view of a TIG welding torch with a constricted nozzle for spot welding according to an embodiment of the present invention; FIG. It is a longitudinal front view of the same TIG welding torch with a constriction nozzle. It is an enlarged longitudinal front view of the main part of the same TIG welding torch with a narrow nozzle. 4 is a cross-sectional view taken along line aa of FIG. 3; FIG. Fig. 3 is an enlarged longitudinal front view of an electrode collet used in a TIG welding torch with a narrow nozzle; 1 shows a constricted nozzle used in a TIG welding torch with a constricted nozzle, (A) is an enlarged front view of the constricted nozzle, (B) is an enlarged longitudinal front view of the constricted nozzle, and (C) is an enlarged cross-sectional view of the constricted nozzle. Fig. 10 is an enlarged vertical cross-sectional view of another example of an electrode nozzle used in a TIG welding torch with a constriction nozzle, and used when the current is 80 A to 200 A (for medium current and large current). Still another example of an electrode nozzle used in a TIG welding torch with a constriction nozzle, which is used for spot welding of a corner joint, (A) is an enlarged longitudinal sectional view of the electrode nozzle, (B) is It is an enlarged bottom view of an electrode nozzle. Still another example of an electrode nozzle used in a TIG welding torch with a constricted nozzle, which is used for spot welding of a T joint, (A) is an enlarged longitudinal sectional view of the electrode nozzle, (B) is An enlarged side view of the electrode nozzle, and (C) an enlarged bottom view of the electrode nozzle.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

1 to 6 show a TIG welding torch 1 with a constricted nozzle for spot welding according to an embodiment of the present invention, and the TIG welding torch 1 with a constricted nozzle is made of two sheets of stainless steel plate, steel plate, copper plate, aluminum plate, etc. It is used for spot welding (tack welding) of the metal plate W (hereinafter referred to as the base material W), and when the arc length is changed according to the size of the welding current, the arc length can be set with a single touch. It is designed to When two base materials W are temporarily attached by spot welding (temporary welding), butt joints, corner joints, edge joints, T joints, lap joints, and the like are used as joint shapes.

The TIG welding torch 1 with a narrow nozzle includes a torch body 2, an electrode collet 4 that is detachably attached to the torch body 2, holds a tungsten electrode rod 3 connected to a cathode, and passes a shielding gas G, A gas passage 5c is provided at the tip of the electrode collet 4 and supports the tungsten electrode rod 3 concentrically to form a gas passage 5c through which the shielding gas G flows between the tungsten electrode rod 3 and the tungsten electrode rod 3 from the gas passage 5c. a constricting nozzle 5 for ejecting shielding gas G toward the tip of the torch body 2, and a conductive tubular ground connection fitting 7 provided at the tip of the torch body 2 and connected to the anode via the ground cable 6. is screwed onto the outer peripheral surface of the ground connection fitting 7 so as to be movable and adjustable in the axial direction of the tungsten electrode rod 3 (longitudinal direction of the tungsten electrode rod 3). 5, and a cylindrical electrode nozzle 8 having conductivity surrounding the tip of the tungsten electrode rod 3 protruding from 5, and the pitch of the male screw 7b formed on the outer peripheral surface of the ground connection fitting 7 and the electrode nozzle 8 The pitch of the female screw 8c that is formed on the inner peripheral surface of the earth connection fitting 7 and screwed into the male screw 7b of the earth connection fitting 7 is formed at the same predetermined pitch, and the tip of the tungsten electrode rod 3 and the tip surface of the electrode nozzle 8 are the same position as the reference position of the electrode nozzle 8, and the arc length display indicating the amount of movement of the electrode nozzle 8 from the reference position is provided on the outer peripheral surface of the ground connection fitting 7 and the outer peripheral surface of the electrode nozzle 8. A section 9 is provided, and the arc length is set by the arc length display section 9 by rotating the electrode nozzle 8 .

As shown in FIG. 2, the torch body 2 includes a cylindrical lower torch body 2A made of synthetic resin (for example, MC nylon (registered trademark)) formed with a small diameter on the tip side (lower end side); A tubular upper torch body 2B made of a synthetic resin (for example, MC nylon (registered trademark)) whose part (lower end) is fitted via an O-ring 10 into a recess formed in the upper end surface of the lower torch body 2A A cylindrical cover body 11 made of a synthetic resin (for example, polycarbonate) having excellent insulating properties is fitted to the outer peripheral surface of the upper torch body 2B.

As shown in FIGS. 2, 3 and 5, the electrode collet 4 is detachably inserted into the cylindrical lower torch body 2A, and has a female thread 4a on the inner peripheral surface of the base end (the inner peripheral surface of the upper end). It is detachably inserted into the cylindrical nozzle fixture 4A made of brass (or copper) having conductivity and the cylindrical upper torch body 2B, and is radially contracted and expanded at the tip (lower end). A small-diameter collet chuck portion 4b with a free diameter is formed, and a male screw 4c is formed on the outer peripheral surface of the collet chuck portion 4b to be screwed into the female screw 4a of the nozzle fixture 4A so as to be axially movable. Shielding gas G supplied from a gas hose 13 connected to the base end of the connection collet 4B via a hose joint 12 is provided. The liquid flows sequentially through the connecting collet 4B and the nozzle fixture 4A.

The inner diameter of the connection collet 4B of the electrode collet 4 and the inner diameter of the nozzle fixture 4A are formed to be larger than the outer diameter of the tungsten electrode rod 3. An annular passage through which the shielding gas G flows is formed between the surfaces and between the inner peripheral surface of the nozzle fixture 4A and the outer peripheral surface of the tungsten electrode rod 3 .

A female screw 4d to which the constriction nozzle 5 is detachably screwed is formed on the inner peripheral surface of the distal end portion (inner peripheral surface of the lower end portion) of the nozzle fitting 4A, and the inner peripheral surface of the intermediate portion of the nozzle fitting 4A is formed with: A first tapered surface 4e whose diameter gradually decreases toward the tip side of the nozzle fixture 4A is formed.

Furthermore, as shown in FIG. 5, the collet chuck portion 4b of the connecting collet 4B is formed with a plurality of split grooves 4f through which the shielding gas G can flow. A through hole 4g is formed to communicate with and facilitate the diameter reduction of the collet chuck portion 4b.

2, 3 and 5, the distal end of the collet chuck portion 4b of the connecting collet 4B is formed with a second tapered surface 4h that engages with the first tapered surface 4e of the nozzle fixture 4A. there is Therefore, when the collet chuck portion 4b of the connecting collet 4B is screwed into the nozzle fixture 4A, the second tapered surface 4h formed on the collet chuck portion 4b of the connecting collet 4B is brought into contact with the first tapered surface 4e of the nozzle fixture 4A. Then, the collet chuck portion 4b of the connecting collet 4B is tightened in a diameter-reducing direction, and the tungsten electrode rod 3 inserted into the electrode collet 4 is clamped and fixed by the inner peripheral surface of the distal end portion of the collet chuck portion 4b.

At this time, the groove width of the split groove 4f of the collet chuck portion 4b is set to a dimension such that a gap through which the shield gas G can flow is formed even if the groove width is narrowed by tightening the collet chuck portion 4b. Therefore, the shielding gas G that has passed through the split groove 4f of the collet chuck portion 4b passes through the annular passage formed between the inner peripheral surface of the nozzle fixture 4A and the outer peripheral surface of the tungsten electrode rod 3, and passes through the constricted nozzle 5. It becomes possible to circulate inside. Further, since the through hole 4g communicating with the split groove 4f is formed in the base end portion of the collet chuck portion 4b, the collet chuck portion 4b can be easily and easily tightened in the direction in which the diameter of the collet chuck portion 4b is reduced. The tungsten electrode rod 3 is firmly clamped and fixed with a small force.

An L-shaped torch cable bar 14 made of a copper plate is attached to the upper end of the connecting collet 4B of the electrode collet 4. The torch cable bar 14 is attached to the torch cable bar 14 via a set screw 15 for a cable. A terminal 16a of the cable 16 is connected and fixed. This torch cable 16 is connected to a cathode terminal of a power control unit (not shown). Therefore, the tungsten electrode rod 3 inserted into the electrode collet 4 is connected to the cathode of the power control unit (not shown) through the electrode collet 4 and the torch cable bar 14. FIG.

The constriction nozzle 5 is arranged on the outer periphery of the tip of the tungsten electrode rod 3 and concentrically supports the tungsten electrode rod 3 in a state where the tip of the tungsten electrode rod 3 protrudes. A passage 5c is formed, and the shielding gas G is jetted from the gas passage 5c to the periphery of the tip portion of the tungsten electrode rod 3 at high speed.

That is, the constriction nozzle 5 is formed in a cylindrical body from a metal member (for example, molybdenum or copper), and as shown in FIGS. A tubular constriction nozzle body 5a arranged concentrically with the rod 3, and protuberances formed on the inner peripheral surface of the constriction nozzle body 5a at predetermined intervals in the circumferential direction so that the tungsten electrode rod 3 is inserted into the constriction nozzle body 5a. and a plurality of positioning ridges 5b extending along the longitudinal direction of the narrow nozzle body 5a held at the central position of the narrow nozzle body 5a. and a plurality of groove-like gas passages 5c through which G flows. A male thread 5d is formed to be detachably screwed into a female thread 4d formed on the peripheral surface.

Further, as shown in FIG. 4, the positioning ridges 5b and the groove-like gas passages 5c are arranged on the inner peripheral surface of the narrow nozzle body 5a at regular intervals in the circumferential direction. Shielding gas G can be evenly flowed around the tip of the tungsten electrode rod 3 from the tip opening.

The ground connection fitting 7 is made of conductive oxygen-free copper and has a cylindrical shape with a flange portion 7a.

The ground connection fitting 7 also has a terminal fastener 17 for connecting the terminal 6 a of the ground cable 6 to the ground connection fitting 7 . The terminal fastener 17 is a small screw screwed onto the flange portion 7a of the ground connection fitting 7 with a washer 18 interposed therebetween. Also, the ground cable 6 is connected to an anode terminal of a power control unit (not shown). Although not shown, the terminal fastener 17 may be a terminal fastener consisting of a headless screw screwed onto the ground connection fitting 7 and a nut screwed onto the headless screw.

Further, a male screw 7b is formed on the outer peripheral surface of the intermediate portion of the ground connection fitting 7, and the electrode nozzle 8 is detachably screwed thereon. An O-ring 19 is fitted to the outer peripheral surface of the ground connection fitting 7 to provide resistance to stop the rotation of the electrode nozzle 8 .

The electrode nozzle 8 is made of a conductive metal material and is formed into a cylindrical shape with a tapered tip. and can be used for various joint shapes (butt joint, corner joint, edge joint, T joint, lap joint, etc.).

That is, as shown in FIGS. 2 and 3, the electrode nozzle 8 is divided into upper and lower parts, and is screwed to the outer peripheral surface of the ground connection fitting 7 so as to be movable and adjustable in the axial direction of the tungsten electrode rod 3. A cylindrical nozzle body 8A made of a relatively inexpensive conductive material (for example, brass) and a tip (lower end) of the nozzle body 8A are detachably attached, and the tip (lower end) is attached to the tip. It is provided with a tubular nozzle tip 8B formed in a constricted shape and made of a conductive material (for example, chromium copper or oxygen-free copper).

The nozzle main body 8A and the nozzle tip 8B have a female screw 8a formed on the inner peripheral surface of the tip of the nozzle main body 8A and a male screw formed on the outer peripheral surface of the base end of the nozzle tip 8B and screwed into the female screw 8a. 8b is detachable, and the nozzle tip 8B can be replaced with another shaped nozzle tip 8B.

Further, the nozzle body 8A is formed to have a diameter larger than that of the nozzle tip 8B. A female screw 8c is formed. The pitch of the male screw 7b formed on the outer peripheral surface of the ground connection fitting 7 and the pitch of the female screw 8c formed on the inner peripheral surface of the base end portion of the nozzle body 8A are formed at the same predetermined pitch. In this embodiment, the pitch of the male screw 7b of the ground connection fitting 7 and the pitch of the female screw 8c of the nozzle body 8A screwed into the male screw 7b are set to 1.0 mm, and the electrode nozzle 8 is set to 1.0 mm. When rotated, the electrode nozzle 8 moves 1.0 mm in the axial direction of the tungsten electrode rod 3 .

Further, on the peripheral wall of the tip portion of the nozzle main body 8A, a plurality of nozzles are formed at predetermined intervals in the circumferential direction to release the shielding gas G in the electrode nozzle 8 to the outside together with the metal vapor generated from the molten pool. A hole-shaped gas vent 8d is formed. The number, shape, size, etc. of the hole-shaped gas vents 8d are such that the shielding gas G in the electrode nozzle 8 can be released to the outside to prevent turbulence of the shielding gas G in the electrode nozzle 8, and It is set so that the metal vapor generated from the molten pool in the electrode nozzle 8 can be discharged to the outside satisfactorily and reliably. In this embodiment, the nozzle main body 8A has four hole-shaped degassing openings 8d formed every 90 degrees along the circumferential direction.

Further, the nozzle tip 8B is formed to have a smaller diameter than the nozzle main body 8A, and the nozzle diameter (inner diameter of the tip opening of the nozzle tip 8B) is formed to a predetermined inner diameter depending on the magnitude of the welding current. For example, when the welding current is small (approximately 10A to 80A), the nozzle diameter is set to 0.7mm, 1.0mm or 2.0mm, and the welding current is medium to large (approximately 80A to 200A). ), the nozzle diameter is set to 3.0 mm, 4.0 mm or 5.0 mm.

When the electrode nozzle 8 is attached to the outer peripheral surface of the ground connection fitting 7 , the electrode nozzle 8 is arranged concentrically with the tip of the tungsten electrode rod 3 protruding from the tip of the constriction nozzle 5 . It surrounds the tip of the tungsten electrode rod 3 protruding from.

Further, when the electrode nozzle 8 is attached to the outer peripheral surface of the ground connection fitting 7, an O-ring interposed between the outer peripheral surface of the ground connection fitting 7 and the inner peripheral surface of the nozzle main body 8A of the electrode nozzle 8 A resistance is applied to the electrode nozzle 8 by 19 to prevent the electrode nozzle 8 from accidentally rotating and moving in the axial direction of the tungsten electrode rod 3 .

Further, the reference position of the electrode nozzle 8 is a position where the tip of the tungsten electrode rod 3 and the tip surface of the electrode nozzle 8 are at the same position. An arc length display section 9 for displaying the amount of movement of the electrode nozzle 8 from a reference position is provided on the outer peripheral surface of the nozzle 8, and the arc length can be set by the arc length display section 9 by rotating the electrode nozzle 8. It's like

The arc length display portion 9 is provided on the outer peripheral surface of the ground connection fitting 7, and is provided on the outer peripheral surface of the electrode nozzle 8, and is provided on the outer peripheral surface of the electrode nozzle 8. The scale 9a and the reference mark 9b indicate the amount of movement of the electrode nozzle 8 from the reference position so that the arc length can be set. It's becoming

As shown in FIG. 1, the scale 9a is provided on the outer peripheral surface of the ground connection fitting 7 over the entire circumference. formed. In the present embodiment, the scale 9a has ten thick lines and ten thin lines alternately arranged to divide the outer peripheral surface of the ground connection fitting 7 into 20 equal parts. It represents that the electrode rod 3 is moved in the axial direction by 0.1 mm. Incidentally, the scale 9a may be directly formed on the outer peripheral surface of the ground connection fitting 7. FIG.

The reference mark 9b is formed by affixing a sheet or seal on which a triangular black mark is printed to the outer peripheral surface of the nozzle main body 8A of the electrode nozzle 8. As shown in FIG. In this embodiment, when the electrode nozzle 8 is at the reference position (the position where the tip of the tungsten electrode rod 3 and the tip surface of the electrode nozzle 8 are at the same position), the reference mark 9b is at the zero position ( (thick line indicating zero position). Note that the reference mark 9b may be formed directly on the outer peripheral surface of the nozzle body 8A.

As shown in FIG. 1, a torch switch 20 is provided on the outer peripheral surface of the torch body 2 of the TIG welding torch with a narrow nozzle. (not shown).

In addition, a power control unit (not shown) supplies the shielding gas G to the TIG welding torch 1 with a constriction nozzle according to the operation of the torch switch 20, and applies a voltage for a predetermined time after the flow of the shielding gas G is stabilized. It is controlled to generate an arc (arc plasma). Further, the current value and time for spot welding are determined by the material, plate thickness, and the like of the base material W. As shown in FIG.

Furthermore, the nozzle diameter of the electrode nozzle 8 (inner diameter of the tip opening of the nozzle tip 8B) is determined according to the magnitude of the welding current. The size (outer diameter) of is adjustable.

FIG. 7 shows another example of the electrode nozzle 8 used in the TIG welding torch 1 with a constriction nozzle, and the electrode nozzle 8 is used when the welding current is medium current to large current (about 80 A to 200 A). , which is attached to the ground connection fitting 7 and is detachably attached to the nozzle body 8A formed in a cylindrical shape with a conductive material (for example, brass) and the tip of the nozzle body 8A, and the tip is the tip A cylindrical nozzle tip 8B formed in a constricted shape and made of a conductive material (for example, chromium copper or oxygen-free copper) is provided, and only the nozzle tip 8B is replaced with a nozzle tip 8B having a different shape. It is what I did.

That is, the nozzle tip 8B, as shown in FIG. 7, has an inner diameter of the tip opening larger than that of the tip opening of the nozzle tip 8B shown in FIGS. is formed in the same shape and structure as the nozzle tip 8B shown in FIGS. In this embodiment, the inner diameter of the tip opening of the nozzle tip 8B is set to 3.0 mm, 4.0 mm or 5.0 mm. The nozzle body 8A shown in FIG. 7 is the same as the nozzle body 8A shown in FIGS. 2 and 3, and the same parts and members are given the same reference numerals.

FIG. 8 shows still another example of the electrode nozzle 8 used in the TIG welding torch with a constriction nozzle. , a nozzle body 8A made of a material having conductivity (for example, brass) and formed in a cylindrical shape, and a tip of the nozzle body 8A are detachably attached, and the tip is formed in a tapered shape to provide conductivity. and a cylindrical nozzle tip 8B made of a material (for example, chromium copper or oxygen-free copper), and only the nozzle tip 8B is replaced with a nozzle tip 8B having a different shape.

That is, as shown in FIG. 8, the nozzle tip 8B has a V-shaped positioning groove 8e formed in the tip surface of the nozzle tip 8B along the diameter direction of the nozzle tip 8B so as to be fitted to the corner of the corner joint. , and the shape and structure of other portions are formed in the same shape and structure as the nozzle tip 8B shown in FIGS. The nozzle body 8A shown in FIG. 8 is the same as the nozzle body 8A shown in FIGS. 2 and 3, and the same parts and members are given the same reference numerals.

FIG. 9 shows still another example of the electrode nozzle 8 used in a TIG welding torch with a narrow nozzle. A nozzle body 8A formed in a cylindrical shape from a material having conductivity (for example, brass) and a tip of the nozzle body 8A are detachably attached, and the tip is formed in a tapered shape. It has a cylindrical nozzle tip 8B made of a conductive material (for example, chromium copper or oxygen-free copper), and only the nozzle tip 8B is replaced with a nozzle tip 8B of another shape.

That is, as shown in FIG. 9, the nozzle tip 8B has a facing positioning surface 8f formed on the outer peripheral surface of the tip portion of the nozzle tip 8B so as to come into surface contact with the corner of the T joint. is formed in the same shape and structure as the nozzle tip 8B shown in FIGS. The nozzle body 8A shown in FIG. 9 is the same as the nozzle body 8A shown in FIGS. 2 and 3, and the same parts and members are given the same reference numerals.

A case of spot-welding two butted base materials W using the TIG welding torch with a constricted nozzle shown in FIG. 1 will be described.

First, the distance (arc length) between the tip of the tungsten electrode rod 3 and the tip surface of the electrode nozzle 8 is set according to the magnitude of the welding current.

That is, the electrode nozzle 8 is set to the reference position (the position where the tip of the tungsten electrode rod 3 and the tip surface of the electrode nozzle 8 are at the same position), and the reference mark 9b of the arc length display section 9 is set to the zero position of the scale 9a. (the thick line indicating the zero position), rotate the electrode nozzle 8 according to the magnitude of the welding current, move the electrode nozzle 8 in the axial direction of the tungsten electrode rod 3, and display the arc length display section. 9 sets the arc length (the distance between the tip of the tungsten electrode rod 3 and the tip surface of the electrode nozzle 8) to a predetermined value (for example, 0.2 mm to 0.5 mm).

After the arc length is set to a predetermined value, the tip surface of the electrode nozzle 8 is brought into surface contact with the spots of the two butted base materials W to be spot-welded.

At this time, the welding conditions such as the welding current, the flow rate of the shielding gas G, the type of the shielding gas G, and the welding time are set to optimum conditions according to the material, plate thickness, and the like of the base material W. Further, the tungsten electrode rod 3 is used as a cathode, and the electrode nozzle 8 is used as an anode. Therefore, the position of the base material W with which the electrode nozzle 8 contacts is grounded.

After the electrode nozzle 8 is brought into contact with the base material W, the torch switch 20 is pressed. Then, the shielding gas G is supplied to the TIG welding torch 1 with a narrow nozzle, and voltage is applied between the tungsten electrode rod 3 and the base material W after the flow of the shielding gas G is stabilized. Then, an arc (arc plasma) is generated between the tip of the tungsten electrode rod 3 and the base material W in the atmosphere of the shielding gas G for a predetermined time. As a result, a part of the base material W is melted, and the base material W is spot-welded.

The shielding gas G supplied from the gas hose 13 to the TIG welding torch with a narrow nozzle flows down through the electrode collet 4 and into the gas passage 5 c of the narrow nozzle 5 .

The shielding gas G that has flowed into the gas passage 5c increases its speed and becomes high-speed gas, and is jetted from the tip opening of the constricted nozzle 5 in a straight line around the arc.

The shielding gas G jetted from the constricted nozzle 5 flows around the tip of the tungsten electrode rod 3 and flows into the space inside the electrode nozzle 8, and then flows into the hole-shaped nozzle body 8A of the electrode nozzle 8. is released to the outside from the gas vent 8d.

The above-described TIG welding torch 1 with a constricting nozzle allows the electrode nozzle 8 to be movable and adjustable in the axial direction of the tungsten electrode rod 3, and has an arc length display 9 such as a scale 9a for displaying the amount of movement of the electrode nozzle 8. Therefore, when changing the arc length according to the magnitude of the welding current, it is sufficient to rotate the electrode nozzle 8 and look at the arc length display section 9, and the setting gauge is unnecessary. position can be easily set at a predetermined position, and the arc length can be set with a single touch.

In the TIG welding torch 1 with a constricted nozzle, the electrode nozzle 8 is vertically divided into a cylindrical nozzle body 8A and a cylindrical nozzle tip 8B, and the nozzle tip 8B is detachable from the nozzle body 8A. Therefore, it is possible to replace only the nozzle tip 8B with one having another shape, and it is possible to correspond to various joint shapes. For example, the nozzle tip 8B shown in FIG. 8, which has a V-shaped positioning groove 8e for fitting the nozzle tip 8B to the corner of the corner joint, or the opposing positioning nozzle that contacts the corner of the T joint in a surface contact state. By replacing the nozzle tip 8B with the nozzle tip 8B shown in FIG. 9 in which the surface 8f is formed, spot welding of corner joints and T-joints can be reliably and easily performed.

Furthermore, since the TIG welding torch 1 with a constricted nozzle has the ground cable 6 connected to the ground connection fitting 7, even when the electrode nozzle 8 is replaced or only the nozzle tip 8B is replaced, grounding is possible. Detachment operation of the cable 6 becomes unnecessary.

Furthermore, in the TIG welding torch 1 with a narrow nozzle, the nozzle body 8A and the nozzle tip 8B are made of a different material having conductivity, for example, the nozzle body 8A is made of relatively inexpensive brass, and the nozzle tip 8B is made of chromium copper. Since the electrode nozzle 8 is made of oxygen-free copper, the cost can be reduced compared to the case where the entire electrode nozzle 8 is made of copper.

Furthermore, since the TIG welding torch 1 with a constricted nozzle has a tungsten electrode rod 3 as a cathode and an electrode nozzle 8 as an anode, the narrowed tip of the electrode nozzle 8 is brought into contact with the base material W. Spot welding (tack welding) can be performed in this state, and the target position of spot welding can be easily determined.

Furthermore, in the TIG welding torch 1 with a narrow nozzle, since the distance between the tip of the tungsten electrode rod 3 and the tip of the electrode nozzle 8 is constant, the arc length can be kept constant.

Furthermore, in the TIG welding torch 1 with a narrow nozzle, since the tip of the tungsten electrode rod 3 is covered with the electrode nozzle 8, it is possible to eliminate the short-circuit phenomenon between the tungsten electrode rod 3 and the base material W, and the arc is generated during welding. and the shielding gas G are not affected by the wind, and the leakage of the arc light to the outside can be minimized. Welding work can be performed safely without being exposed to harmful ultraviolet rays or infrared rays. Moreover, since the shielding gas G flows through the electrode nozzle 8, it is possible to prevent the tungsten electrode rod 3 from being oxidized by oxygen.

Furthermore, the TIG welding torch 1 with a constricting nozzle is provided with the constricting nozzle 5 that concentrically supports the tungsten electrode rod 3 and causes the shielding gas G to flow around the tungsten electrode rod 3 at high speed. The tungsten electrode rod 3 can be accurately and reliably set at a predetermined position at the time of replacement.

Furthermore, in the TIG welding torch 1 with a narrow nozzle, the electrode nozzle 8 is formed with a hole-shaped gas vent 8d for releasing the shielding gas G in the electrode nozzle 8 to the outside. Gas turbulence can be prevented, and the metal vapor generated from the molten pool can be discharged to the outside together with the shielding gas G from the slit-shaped groove-shaped gas vent 8d. As a result, the TIG welding torch 1 with a constricted nozzle can prevent re-adhesion and mixing of the metal vapor into the molten metal, perform high-quality spot welding, and the metal vapor adheres to the tip of the tungsten electrode rod 3. can be prevented, and the life of the tungsten electrode rod 3 can be extended.

In this way, the above-described TIG welding torch 1 with a constricted nozzle can achieve the above-described effects, so even beginners can easily and easily learn the technique and perform good spot welding (tack welding). can be performed, workability can be improved, welding quality can be improved, and productivity can be improved.

In each of the above-described embodiments, the electrode nozzle 8 is divided into upper and lower parts to form a cylindrical nozzle main body 8A and a cylindrical nozzle tip 8B. The nozzle body 8A and the nozzle tip 8B of No. 8 may be integrally formed.

In each of the above-described embodiments, the outer peripheral surface of the ground connection fitting 7 is provided with a scale 9a indicating the amount of movement of the electrode nozzle 8 from the reference position. In another embodiment, the scale 9a is provided on the outer peripheral surface of the electrode nozzle 8, and the reference mark 9b is provided on the outer peripheral surface of the ground connection fitting 7. can be

1 is a TIG welding torch with a narrow nozzle, 2 is a torch body, 3 is a tungsten electrode rod, 4 is an electrode collet, 5 is a narrow nozzle, 5c is a gas passage, 7 is a ground connection fitting, 7b is a male screw, 8 is a nozzle for electrodes, 8A is a nozzle main body, and 8B is a nozzle. Tip 8c is a female screw 8d is a gas vent 8e is a positioning groove 8f is a positioning surface 9 is an arc length display part 9a is a scale 9b is a reference mark 19 is an O-ring G is a shield gas

Claims (4)

a torch body;
an electrode collet that is detachably attached to the torch body, holds a tungsten electrode rod connected to the cathode, and passes a shielding gas;
Provided at the tip of the electrode collet, the tungsten electrode rod is concentrically supported to form a gas passage through which the shielding gas flows between the tungsten electrode rod and the tungsten electrode rod, and the shield extends from the gas passage toward the tip of the tungsten electrode rod. a narrow nozzle for ejecting gas;
a conductive cylindrical ground connection fitting provided at the tip of the torch body and connected to the anode via the ground cable;
It is screwed onto the outer peripheral surface of the ground connection fitting so as to be movable and adjustable in the axial direction of the tungsten electrode rod, the tip portion is formed in a tapered shape, and a conductive wire surrounds the tip portion of the tungsten electrode rod protruding from the constriction nozzle. and a cylindrical electrode nozzle having properties,
The pitch of the male screw formed on the outer peripheral surface of the ground connection fitting and the pitch of the female screw formed on the inner peripheral surface of the electrode nozzle and screwed into the male screw are formed to be the same predetermined pitch, and the tungsten electrode The reference position of the electrode nozzle is the position where the tip of the rod and the tip surface of the electrode nozzle are at the same position,
An arc length display section for setting the arc length by displaying the amount of movement of the electrode nozzle from a reference position is provided on the outer peripheral surface of the ground connection fitting and the outer peripheral surface of the electrode nozzle,
The arc length display part is provided on either the outer peripheral surface of the ground connection fitting or the outer peripheral surface of the electrode nozzle, and has a scale indicating the amount of movement of the electrode nozzle from the reference position, a reference mark provided on the other of the outer peripheral surfaces of the electrode nozzle and pointing to the scale when the electrode nozzle is rotated from the reference position;
The electrode nozzle is divided into upper and lower parts, a conductive cylindrical nozzle body screwed to the outer peripheral surface of the ground connection fitting so as to be movable and adjustable in the axial direction of the tungsten electrode rod, and a nozzle body. a conductive cylindrical nozzle tip detachably provided at the tip portion, the tip portion of which is formed in a tapered shape ;
For spot welding, wherein the nozzle body and the nozzle tip are made of different conductive materials, and a gas vent is formed in the peripheral wall of the nozzle body for releasing the shielding gas in the electrode nozzle to the outside. TIG welding torch with constricted nozzle. 2. The spot welding device according to claim 1, wherein an O-ring is interposed between the outer peripheral surface of the ground connection fitting and the inner peripheral surface of the electrode nozzle to provide resistance to stop rotation of the electrode nozzle. TIG welding torch with constricted nozzle. 2. The spot according to claim 1, wherein a V-shaped positioning groove is formed in the front end surface of the nozzle tip along the diameter direction of the nozzle tip and is fitted to the corner of the corner joint. TIG welding torch with narrow nozzle for welding. TIG welding with a constricted nozzle for spot welding according to claim 1, characterized in that an opposing positioning surface is formed on the outer peripheral surface of the tip of the nozzle tip so as to contact the corner of the T joint in a surface contact state. torch.

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