Welding torch and method for cooling the same

Abstract

To provide a welding torch and a method for cooling the same, which can perform efficient cooling with a simple and low-cost structure.SOLUTION: This welding torch comprises: a torch barrel to which a tip member is attached; and an exterior body. The torch barrel includes a barrel outer cylinder, and a barrel inner cylinder. A supply path and a recovery path for cooling water are formed on the outer circumference surface of the barrel inner cylinder. The barrel inner cylinder has an inner cylindrical exposed part. A supply side opening and a recovery side opening are formed on the base end side of the outer circumference surface of the inner cylindrical exposed part. A connection with a tip body is provided on the axial tip side of the inner cylindrical exposed part. The connection is connected such that the tip body covers the outer circumference side of the inner cylindrical exposed part. At least the connection, the supply side opening, and the recovery side opening are arranged inside an outer cylindrical body. A seal is provided to tightly seal parts between the outer cylindrical body and the tip body and between the outer cylindrical body and the barrel outer cylinder.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a welding torch and a method for cooling the same. [Background technology]

[0002] Normally, when the welding current applied during welding is high, the heat radiated from the arc increases, and the temperature of the welding torch itself rises. In particular, the temperature of the contact tip at the tip of the welding torch close to the arc generation position and the nozzle rises significantly. When the temperature of the welding torch rises, there is a risk that the amount of wear of the contact tip and the amount of spatter adhering to the nozzle will increase. In addition, there is a risk that the fastening part connecting the contact tip and the tip body will burn out. For this reason, a configuration has been disclosed in which a water-cooling mechanism is provided in the welding torch to efficiently cool the welding torch.

[0003] Patent Document 1 describes a welding torch in which cooling water is circulated up to the axial tip of the welding torch by forming outward and return water passages for cooling inside a tip body and a nozzle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-93270 A Summary of the Invention [Problem to be solved by the invention]

[0005] The welding torch described in Patent Document 1 is capable of circulating cooling water up to the axial end of the tip body and nozzle, but the cost is high because the structures of the tip body and nozzle, which are consumables, are complicated. In addition, because a cavity for cooling is formed inside the tip body, it is not possible to process the tip body to provide other special mechanisms, which reduces versatility.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a highly versatile welding torch that can be efficiently cooled with a simple and low-cost configuration, and a cooling method for a welding torch. [Means for solving the problem]

[0007] The above object of the present invention can be achieved by the following configuration. (1) A welding torch used in gas-shielded arc welding, The welding torch is A torch barrel portion to which a tip body is attached at the tip side; an outer cylinder body attached to the torch barrel portion so as to exteriorly surround the torch barrel portion; Equipped with The torch barrel portion has a barrel outer cylinder and a barrel inner cylinder inserted into the barrel outer cylinder, A supply passage for supplying cooling water between the inner barrel and the outer barrel, and a recovery passage for recovering cooling water between the inner barrel and the outer barrel are formed on the outer circumferential surface of the barrel. The barrel inner cylinder has an exposed portion extending toward the axial tip side of the barrel outer cylinder, A supply side opening at an axial tip end side of the supply path and a recovery side opening at an axial tip end side of the recovery path are formed on a base end side of an outer circumferential surface of the inner cylinder exposed portion, a connecting portion to which an axial tip end side of the inner cylinder exposed portion is connected is provided on a rear end side of the tip body, The connection portion is formed so as to cover an outer circumferential side of the inner cylinder exposed portion, the outer cylinder body has an interior portion that interiorly accommodates at least the connection portion, the supply side opening, and the recovery side opening, The interior portion is provided with a seal portion that seals between the external cylinder body and the tip body, and between the external cylinder body and the gun barrel. Welding torch. (2) The sealing portion has at least an insulator and a waterproof member, The waterproof member seals between an outer peripheral surface of the insulator and the outer cylinder body arranged radially outside the insulator, or between an inner peripheral surface of the insulator and the tip body or the gun barrel arranged radially inside the insulator. The welding torch described in (1). (3) A cylindrical attachment body is inserted into the torch barrel portion and its axial movement toward the tip side is restricted by a restricting portion provided on the torch barrel portion, The outer cylinder is fastened to the mounting body at a position on the axial tip side of the restricting portion, so that the axial movement of the outer cylinder is restricted while the outer cylinder is sheathed to the tip body and the torch barrel portion. The welding torch described in (1). (4) The tip body has an eccentric guide portion having a first inner diameter, and a wire pressing portion that radially eccentrically displaces the welding wire inserted into the eccentric guide portion, a contact tip connected to the axial tip side of the tip body, the contact tip being formed along the axial direction from a tip opening formed at the tip to a rear opening, and having a guide hole for guiding the welding wire; The guide hole has a second inner diameter smaller than the first inner diameter. A welding torch according to any one of (1) to (3). (5) A base end guide portion having a third inner diameter is provided on a base end side of the eccentric guide portion, The third inner diameter is smaller than the first inner diameter and larger than the second inner diameter. (4) A welding torch as described in (1). (6) The wire pressing portion has at least a pressing member that contacts the welding wire and an elastic member that presses the pressing member against the welding wire, The pressing member is a spherical member, The elastic member is a leaf spring member. (4) A welding torch as described in (1). (7) The tip body has a body rear portion in which the connection portion is provided, and a body front portion detachably attached to a front end side of the body rear portion. The welding torch described in (1). (8) providing a metallic orifice in the tip body; The welding torch described in (1). (9) The orifice has a cylindrical cover body that extends toward a tip end in an axial direction and covers an outer peripheral surface of the tip body. (8) A welding torch as described in (8). (10) A method for cooling a welding torch used in gas-shielded arc welding, comprising the steps of: The welding torch is A torch barrel portion to which a tip body is attached at the tip side; an outer cylinder body attached to the torch barrel portion so as to exteriorly surround the torch barrel portion; Equipped with The torch barrel portion has a barrel outer cylinder and a barrel inner cylinder inserted into the barrel outer cylinder, A supply passage for supplying cooling water between the inner barrel and the outer barrel, and a recovery passage for recovering cooling water between the inner barrel and the outer barrel are formed on the outer circumferential surface of the barrel. The barrel inner cylinder has an exposed portion extending toward the axial tip side of the barrel outer cylinder, A supply side opening at an axial tip end side of the supply path and a recovery side opening at an axial tip end side of the recovery path are formed on a base end side of an outer circumferential surface of the inner cylinder exposed portion, a connection portion for connecting to the tip body is provided on the axial end side of the exposed portion of the inner cylinder; the connecting portion is connected such that the tip body covers an outer circumferential side of the exposed portion of the inner cylinder, the outer cylinder body has an interior portion that interiorly accommodates at least the connection portion, the supply side opening, and the recovery side opening, The internal part is provided with a seal part for sealing between the external cylinder body and the tip body, and between the external cylinder body and the gun barrel, a supply step in which cooling water is supplied from the supply side opening to the interior part; a cooling step of cooling the connection portion with the cooling water; a recovery step in which the cooling water having cooled the interior portion is recovered from the recovery side opening; having How to cool a welding torch. Effect of the Invention

[0008] According to the present invention, the tip body can be efficiently cooled with a simple and low-cost structure in which the rear end of the tip body is extended to form a connection part that covers the axial tip side of the barrel inner cylinder. In addition, the connection part can be applied to tip bodies that have been specially processed in the axial middle part of the tip body, which increases versatility. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic side view of a welding robot in which a welding torch to which the present invention is applied is used. [Diagram 2] FIG. 2 is a plan view showing a welding torch to which the present invention is applied. [Diagram 3] FIG. 3 is a side view showing a welding torch to which the present invention is applied. [Figure 4] FIG. 4 is an exploded perspective view of a welding torch to which the present invention is applied. [Diagram 5] FIG. 5 is a cross-sectional view of the welding torch taken along line AA, showing the circulation path of the cooling water. [Figure 6] FIG. 6 is a cross-sectional view taken along line BB of a welding torch showing a current forcing mechanism. [Figure 7] FIG. 7 is a cross-sectional view showing the wire pressing portion. [Figure 8] FIG. 8 is a central cross-sectional view showing another embodiment of the tip body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the configuration of a welding torch to which the present invention is applied will be described with reference to the accompanying drawings. Note that each drawing is created for the purpose of explaining the present invention, and the embodiment of the present invention is not limited to the contents of the drawings.

[0011] First, in order to grasp the overall picture of a welding torch to which the present invention is applied, a welding robot using the welding torch will be described with reference to Fig. 1. Fig. 1 is a schematic side view of a welding robot using a welding torch according to an embodiment.

[0012] As shown in Fig. 1, the welding robot 1 includes a wire pack 2, a torch cable 3, a wire feeder 4, a welding power source 5, a manipulator 6, and a welding torch 10. Note that the reference character A in Fig. 1 denotes a base material to be welded.

[0013] 1, the wire pack 2 is a supply source of the welding wire W and stores a predetermined amount of the welding wire W. As the welding wire W, for example, a copper-plated wire, a non-copper-plated wire, etc. can be used.

[0014] Torch cable 3 supplies welding current supplied from welding power source 5, welding wire W stored in wire pack 2, and shielding gas supplied from a shielding gas storage device (not shown) to welding torch 10. One end of torch cable 3 is connected to wire feeder 4, and the other end is connected to welding torch 10.

[0015] The wire feeder 4 feeds the welding wire W to the welding torch 10 by using a roller or the like via the torch cable 3. By providing this wire feeder 4, the welding wire W is automatically supplied to the welding torch 10.

[0016] The welding power source 5 is a source of a welding current, and supplies the welding current to the welding torch 10 via the wire feeder 4 and the torch cable 3 .

[0017] The manipulator 6 is an articulated robot having a welding torch 10 attached to its tip, and its operation is controlled by a robot control device (not shown).

[0018] In the following embodiment, the extension direction of the welding torch 10 is referred to as the axial direction. The direction in which the welding wire W is paid out relative to the axial direction of the welding torch 10 is referred to as the front or tip side. The opposite direction to the payout direction of the welding wire W relative to the axial direction of the welding torch 10 is referred to as the rear or base side.

[0019] Next, the configuration of the welding torch 10 according to this embodiment will be described with reference to Fig. 2 to Fig. 7. Fig. 2 to Fig. 3 are a plan view and a side view showing a welding torch to which the present invention is applied, Fig. 4 is an exploded perspective view of a welding torch to which the present invention is applied, Fig. 5 is a cross-sectional view of the welding torch showing a cooling water circulation path, Fig. 6 is a cross-sectional view of the welding torch showing a forced current mechanism, and Fig. 7 is a cross-sectional view showing a wire pressing part. Note that the conduit tube 13 and the welding wire W are omitted in Fig. 5.

[0020] The welding torch 10 automatically feeds a welding wire W into a cylinder and performs arc welding using the welding wire W. As shown in Fig. 2, the welding torch 10 is equipped with a current-carrying fitting 11 and a cooling water supply unit 12. The current-carrying metal fitting 11 is for applying a voltage to the nozzle, thereby detecting contact between the nozzle 16 and the base material A. The cooling water supply unit 12 is for circulating and supplying cooling water to the welding torch .

[0021] (Welding torch 10) As shown in FIG. 4, the welding torch 10 includes a torch barrel portion 20, an orifice 14, a tip body 30, a contact tip 40, a nozzle attachment mechanism 50, a nozzle 16, and a sleeve-shaped seal portion 60. The tip body 30 has a forced current mechanism for making the welding wire W eccentric, as an example of a special mechanism provided by machining the axial midsection. The nozzle attachment mechanism 50 has a nut member 51 and an outer cylinder body 52 , and detachably attaches the nozzle 16 to the tip side of the torch barrel portion 20 . The seal portion 60 has a first seal portion 60A and a second seal portion 60B, and is inserted into the outer cylinder body 52.

[0022] (Torch barrel part 20) The torch barrel 20 has a cylindrical barrel inner cylinder 21 and a barrel outer cylinder 22 into which the barrel inner cylinder 21 is inserted. The barrel inner cylinder 21 and the barrel outer cylinder 22 are integrated with each other with the outer surface of the barrel inner cylinder 21 fitted into the inner surface of the barrel outer cylinder 22. The barrel inner cylinder 21 is formed longer than the barrel outer cylinder 22 so that it protrudes axially from the front and rear ends of the barrel outer cylinder 22.

[0023] A conduit tube 13 that guides the welding wire W supplied from the torch cable 3 is inserted into the barrel inner cylinder 21. The barrel inner cylinder 21 is attached such that its rear side is connected to the torch cable 3 and the tip body 30 extends from its axial tip side.

[0024] The inner barrel portion 21 has an exposed inner barrel portion 21a that extends further toward the axial tip side than the outer barrel portion 22. As shown in Figures 4 and 5, a pair of notched surfaces are formed along the longitudinal direction on the outer peripheral surface of the inner barrel section 21 between the inner barrel section 21 and the outer barrel section 22 to form a supply passage 23 for supplying cooling water and a recovery passage 24 for recovering the cooling water. In addition, at the base end side of the inner tube exposed portion 21a, which is the boundary position between the inner tube exposed portion 21a and the barrel outer tube portion 22, there are formed a supply side opening 23a that opens to the axial tip side of the supply path 23, and a recovery side opening 24a that opens to the axial tip side of the recovery path 24. Further, in the inner cylinder exposed portion 21a, male thread portions 21b for fastening the tip body 30 are formed on the axial tip ends of the supply side opening 23a and the recovery side opening 24a. Furthermore, at the tip end of the inner cylinder exposed portion 21a, an annular inclined portion 21c that abuts against the tip body 30 is formed by cutting out the outer circumferential edge in an annular shape.

[0025] A supply side connection part and a recovery side connection part (not shown) are formed on the axial base end side of the supply path 23 and the recovery path 24, which are connected to the cooling water supply unit 12. The cooling water supply unit 12 connected to the supply side connection part and the recovery side connection part supplies cooling water to the supply path 23 and recovers cooling water from the recovery path 24.

[0026] (Orifice 14) The orifice 14 includes a mechanism for rectifying the flow of the shielding gas. When orifice 14 is attached to tip body 30, multiple through holes 14a through which shielding gas flows are formed at equal intervals in the circumferential direction in positions close to through holes 30a formed in tip body 30. This allows orifice 14 to smoothly guide the shielding gas that has flowed into the inner periphery to through holes 14a, preventing the shielding gas from causing turbulence.

[0027] A cover body 15 made of a highly thermally conductive metal member molded into a cylindrical shape is attached and fixed integrally to the front end side of the orifice 14. The cover body 15 covers the entire periphery of the front part of the chip body 30 by attaching the orifice 14 to a predetermined position of the chip body 30. This increases the thickness of the cover body 15 (or the orifice 14) in addition to the thickness of the chip body 30, and increases the cross-sectional area of ​​heat conduction, improving the cooling performance. This configuration can be seen in Figures 5 and 6. Note that, examples of metals with high thermal conductivity include Cu, Ag, or alloys mainly composed of either Cu or Ag, but brass is most preferable from the viewpoint of cost.

[0028] The orifice 14 has a flange portion 14b on the rear end side. The front surface of the flange portion 14b is engaged with a step portion 16b formed on the inner surface of the nozzle 16 via an insulating ring 17 inserted from the front of the orifice 14, thereby restricting the orifice 14 from sliding forward beyond a specified position. This can reliably prevent the metallic orifice 14 and cover body 15 from coming into contact with the nozzle 16 and causing electrical current to flow. This configuration can be seen in FIGS.

[0029] (Chip body 30) The tip body 30 is a cylindrical member extending in the axial direction, and includes a mechanism for supporting the orifice 14 and the contact tip 40. The tip body 30 is formed of an electrically conductive material such as a metal.

[0030] A cylindrical orifice 14 is inserted into the tip of the tip body 30 from the tip end. In addition, a plurality of through holes 30a through which the shielding gas flows are formed at equal intervals along the circumferential direction in the part of the tip body 30 where the orifice 14 is attached. This configuration can be seen in FIG. 4.

[0031] A female screw portion 35 to which the contact tip 40 is fastened is formed on the inner surface at the tip of the tip body 30. A tapered portion 35a is formed on the axial tip side of the female screw portion 35 at the tip of the tip body 30, the diameter of which increases toward the opening. A connecting portion 39 is provided on the rear end side of the tip body 30, which is connected to the gun barrel inner cylinder portion 21 so as to cover the outer circumferential surface of the inner cylinder exposed portion 21a. A female screw 34 is formed on the inner surface of the rear end of the connecting portion 39, to which the male screw 21b formed on the front end of the barrel inner cylinder 21 is fastened. At this time, the connecting portion 39 on the rear end side of the tip body 30 covers the front half of the inner cylinder exposed portion 21a. In other words, the connecting portion 39 covers the entire outer circumferential surface of the inner cylinder exposed portion 21a on the axial tip side of the supply side opening 23a and the recovery side opening 24a. A tapered section 39a is formed on the inner surface of the front part of the connecting section 39, which expands in diameter to match the exposed part of the inner cylinder 21a, and comes into surface contact with the inclined section 21c formed at the tip of the exposed part of the inner cylinder 21a. This makes it possible to increase the contact area between the tip body 30 and the inner cylinder part 21 of the gun barrel. Please refer to Figures 5 and 6 for this configuration.

[0032] Next, the current forcing mechanism provided in the tip body 30 and the contact tip 40 will be described with reference to FIGS. The tip body 30 guides the welding wire W supplied from the rear torch barrel portion 20 side toward the contact tip 40 in front. The tip body 30 includes a wire pressing portion 33 that causes the inserted welding wire W to be eccentric, an eccentric guide portion 31 that forms a cylindrical space (hereinafter referred to as a pressing space) in which the welding wire W is eccentric, and a base end guide portion 32 that forms a cylindrical space disposed rearward of the eccentric guide portion 31. This configuration may be seen in FIG.

[0033] A pressing space is formed on the inner peripheral surface of the tip body 30 by the eccentric guide part 31. The eccentric guide part 31 is disposed in the front half of the tip body 30, and a wire pressing part 33 is provided in the middle of the axial direction. The pressing space within the eccentric guide part 31 has a predesigned first inner diameter R1.

[0034] The wire pressing portion 33 includes a spherical pressing member 36 that presses the welding wire W inserted into the eccentric guide portion 31, a biasing member 37 that biases the pressing member 36 radially outward, a holding portion 38 provided on the tip body 30 to hold the pressing member 36 and the biasing member 37, and a cover body 15 that covers the pressing member 36 and the biasing member 37 along the outer circumferential surface of the tip body 30. This configuration may be seen in FIG. 6.

[0035] The retaining portion 38 has a groove portion 38A formed by recessing the outer surface of the eccentric guide portion 31 over the entire circumferential direction, a pair of cutout surfaces 38B, 38B formed at positions 180° symmetrical with respect to the cylindrical bottom surface of the groove portion 38A, and a through hole 38C that passes radially between one of the cutout surfaces 38B and the pressing space. The diameter of the through hole 38C is slightly larger than the width direction of the cutout surface 38B. This configuration may be seen in FIG. 7.

[0036] The pressing member 36 is a steel ball that is fitted and housed in the through hole 38C, and is held so as to be movable radially along the through hole 38C. The diameter of the pressing member 36 is larger than the first inner diameter R1 of the eccentric guide part 31, and smaller than the outer diameter of the eccentric guide part 31. Therefore, the steel ball that is the pressing member 36 can be prevented from entering the eccentric guide part 31.

[0037] The biasing member 37 is a leaf spring formed in a C-shape along the groove 38A, and has a pair of clamping portions 37B, 37C that clamp the pair of cutout surfaces 38B, 38B, and a connecting portion 37A that extends in an arc shape along the groove 38A and connects the pair of clamping portions 37B, 37C. An example of a leaf spring formed in a C-shape is a rod clamp. The clamping portion 37C on one side is bent inward so as to press the spherical pressing member 36 in a direction to push it into the through hole 38C. The clamping portion 37B on the other side has an abutment surface 37B1 that abuts against the entire width of the cutout surface 38B, and a locking portion 37B2 formed by bending the end of the clamping portion 37B relative to the abutment surface 37B1 so as to follow the groove 38A. This configuration can be seen in FIG. 7.

[0038] The cover body 15 is a cylindrical member that is attached and fixed integrally to the orifice 14. The cover body 15 is formed so that its axial direction is longer than the groove portion 38A, and the orifice 14 is fitted to a predetermined position of the tip body 30, so that the cover body 15 is attached so as to cover the entire groove portion 38A. By using cover body 15 to cover the outer periphery of groove portion 38A in which pressing member 36 and biasing member 37 are set, pressing member 36 can be reliably prevented from coming off through hole 38C during welding work. That is, the cover body 15 has a function of improving the cooling performance of the tip body 30 and a function of covering the pressing member .

[0039] The base end guide portion 32 is disposed on the inner circumferential surface of the connecting portion 39 and is constituted by the tip portion of the conduit tube 13 inserted into the inner tube exposed portion 21 a fastened to the inner circumferential surface of the connecting portion 39 . The inner diameter of the conduit tube 13 defines a third inner diameter of the proximal guide portion 32. As shown in Fig. 6, the third inner diameter R3 is smaller than the first inner diameter R1.

[0040] (Contact Tip 40) The contact tip 40 is a cylindrical member extending in the axial direction, and the front half is formed in a truncated cone shape with a diameter decreasing toward the tip. A tip opening 42a is formed at the tip of the contact tip 40, from which the welding wire W is fed. The contact tip 40 is made of a metallic material having electrical conductivity, such as copper, and supplies a welding current to the welding wire W.

[0041] A male thread portion 45 is formed at the rear end of the contact tip 40 to be fastened to the female thread portion 35 at the axial end side of the tip body 30 . An inclined portion 45a is formed on the axial front side of the male thread portion 45 of the contact tip 40, which abuts against a tapered portion 35a formed on the axial front side of the female thread portion 35 of the tip body 30. This makes it possible to increase the contact area between the contact tip 40 and the tip body 30.

[0042] The inner surface of the contact tip 40 has a cylindrical connecting portion 44, a tapered portion 43 whose diameter decreases from the front end of the connecting portion 44 toward the axial front side, and a guide hole 42 formed along the axial direction from a rear end opening 42b communicating with the tip of the tapered portion 43 to a tip opening 42a, and which guides the welding wire W.

[0043] The guide hole 42 is formed along the central axis of the tip 40, and has a tip guide length T, which is the axial length from the tip opening 42a to the rear opening 42b, and a second inner diameter R2. The second inner diameter R2 is smaller than the first inner diameter R1 and the third inner diameter R3, and is larger than the wire diameter of the welding wire W.

[0044] The tip guide length T and the second inner diameter R2 are set so that the welding wire W eccentric from the central axis of the tip body 30 and the contact tip 40 can be brought into contact with the rear end opening 42b and the tip opening 42a at the front and rear ends of the guide hole 42 by the wire pressing portion 33. This configuration may be seen in FIG. 6. Specifically, it is desirable that the second inner diameter be 1.05 to 1.35 times the wire diameter of the welding wire W.

[0045] The tapered portion 43 is formed so that its diameter gradually decreases from the rear end to the front end. In the illustrated example, the rear end of the tapered portion 43 communicates with the front end side of the connecting portion 44, which has a diameter larger than the first inner diameter R1, and the front end of the tapered portion 43 communicates with the rear end opening 42b of the guide hole 42, which has a second inner diameter R2.

[0046] The tapered portion 43 and the connecting portion 44 are not limited to the above-mentioned shape as long as the welding wire W bent by the wire pressing portion 33 does not come into contact with the tip body 30 and the contact tip 40 between the position where the welding wire W is pressed by the pressing member 36 and the rear end opening 42b of the guide hole 42.

[0047] According to the tip body 30 and contact tip 40 equipped with the above-mentioned forced current mechanism, the welding wire W supplied from the torch barrel 20 is eccentrically moved by the wire pressing portion 33, and contacts the tip body 30 and the contact tip 40 at a third contact position X3 located at the tip position of the base end guide portion 32 (conduit tube 13) having a third inner diameter R3, a first contact position X1 pressed by the pressing member 36 within the eccentric guide portion 31 having a first inner diameter R1, a second contact position X2 located near the rear end opening 42b of the guide hole 42, and a tip contact position X0 located near the tip opening 42a of the guide hole 42. At this time, in the axial direction of the tip body 30 and the contact tip 40, the section between the third contact position X3 and the first contact position X1 is defined as a first bending section L1, and the section between the first contact position X1 and the second contact position X2 is defined as a second bending section L2.

[0048] That is, regardless of whether the welding wire W has a bent tendency, the welding wire W can be forcibly brought into contact with the vicinity of the tip position of the contact tip 40 with a predetermined contact force. In other words, it is possible to forcibly supply power to the welding wire W. As a result, even if the tip opening 42a of the contact tip 40 widens due to a welding operation, it is possible to maintain the supply of power to the welding wire W, thereby extending the life of the contact tip 40.

[0049] In addition, by adopting a spherical pressing member 36, the wire pressing portion 33 is able to reduce the frictional force in the feeding direction by the pressing member 36, which decenters the welding wire W, making point contact with the welding wire W being fed and sliding while rotating, thereby preventing the supply resistance of the welding wire W from increasing more than necessary.

[0050] (Nozzle attachment mechanism 50) The nozzle attachment mechanism 50 has a nut member 51 that is slidably provided along the axial direction of the barrel outer tubular portion 22 , and an outer tubular body 52 that is interposed between the nut member 51 and the nozzle 16 .

[0051] The nut member 51 is a cap nut that is inserted into the barrel outer tubular portion 22 and is provided so as to be able to slide freely along the barrel outer tubular portion 22. In this way, the nut member 51 functions as an attachment body for attaching the barrel body 52, in which the nozzle 16 is provided, to the barrel outer tubular portion 22.

[0052] The nut member 51 has a cylindrical shape with a bottom that is open at the front. A through hole 51c is formed in the bottom 51b of the nut member 51 so that the barrel outer cylinder 22 can be inserted therethrough. A female screw portion 51a for fastening the outer cylinder body 52 is formed on the inner front side of the nut member 51.

[0053] The nut member 51 is restricted in its axial movement toward the tip end by the restricting member 53 and the positioning member 54 . The positioning member 54 is an annular member that fits into an annular groove formed on the outer surface of the tip of the barrel 22. The restricting member 53 is a ring-shaped member made of resin, and its movement toward the tip in the axial direction is restricted by the positioning member 54. The nut member 51 is restricted from contacting the torch barrel 20 by the restricting member 53 abutting against the bottom 51b, and is restricted from moving axially toward the tip at a predetermined position on the tip side of the barrel outer cylinder 22. This configuration can be seen in Figures 5 and 6.

[0054] The outer cylinder 52 has a cylindrical shape. The inner diameter of the outer cylinder 52 is formed to be larger than the outer diameter of the gun barrel outer cylinder 22 and the outer diameter of the tip body 30. As a result, an interior portion 55 is formed on the inner circumferential surface of the outer cylinder 52, which at least covers the connection portion 39, has front and rear ends separated by a seal portion 60 described below, and communicates with the supply side opening 23a and the recovery side opening 24a. Cooling water is supplied from the supply side opening 23a to the interior portion 55, and the supplied cooling water is discharged from the recovery side opening 24a. In addition, the front and rear ends of the interior portion 55 are sealed by seal portions 60. This configuration may be seen in Figs. 5 and 6.

[0055] A male screw portion 52a is formed on the outer surface of the tip end of the outer cylinder 52 as a mechanism for supporting the nozzle 16, and the rear end of the nozzle 16 is fastened to the male screw portion 52b. The male screw portion 52b is formed on the outer surface of the rear end of the outer cylinder 52, and the female screw portion 51a formed on the nut member 51 is fastened to the male screw portion 52a.

[0056] With the nozzle mounting mechanism 50 having this configuration, the nut member 51 is prevented from sliding forward relative to the regulating member 53, while the rear portion of the outer cylinder body 52 is fastened to the front portion of the nut member 51, thereby preventing the nut member 51 from sliding rearward relative to the regulating member 53. That is, the nozzle attachment mechanism 50 can fix the axial positions of the outer cylinder 52 and the nut member 51 with respect to the torch barrel 20. Therefore, the nozzle 16 fastened to the outer cylinder 52 can be provided so as to extend toward the axial tip side of the torch barrel 20.

[0057] In the above example, the nozzle 16 is configured to be detachable from the outer cylinder 52, but the outer cylinder 52 and the nozzle 16 may be integrally molded. In this case, the nozzle 16 is directly attached to the nut member 51 in a detachable manner. Furthermore, the restricting member 53 is not limited to the above configuration as long as it is capable of positioning the nut member 51 and the outer cylinder body 52 at a predetermined position on the tip side of the barrel outer cylinder portion 22. For example, the restricting member 53 may not be a separate member from the barrel outer cylinder portion 22, but may be configured such that a step for positioning the nut member 51 is integrally formed on the outer surface of the barrel outer cylinder portion 22.

[0058] (Nozzle 16) The nozzle 16 has a mechanism for injecting a shielding gas, such as argon or carbon dioxide gas, supplied from a gas supply device (not shown) onto the base material A to be welded. The nozzle 16 is formed in a cylindrical shape capable of housing the tip body 30, the orifice 14, and the contact tip 40 in an integrally assembled state therein.

[0059] A female screw portion 16a is formed on the inner peripheral surface of the rear portion of the nozzle 16 to which the male screw portion 52a of the outer cylinder body 52 is fastened. The female screw portion 16a of the nozzle 16 extends to the vicinity of the center in the front-rear direction of the outer cylinder body 52 or to a position rearward of the center in the front-rear direction. In other words, the rear side in the front-rear direction of the female screw portion 16a of the nozzle 16 extends to the vicinity of the supply side opening 23a and the recovery side opening 24a in a side view. This configuration can be seen in Figures 5 and 6. That is, the contact area between the nozzle 16 and the outer cylinder 52 can be maximized.

[0060] (Sealing part 60) The seal portion 60 has a first seal portion 60A on the axial front side and a second seal portion 60B on the axial rear side. The first seal portion 60A is configured by attaching an O-ring, which is a waterproof member, to the first sleeve 61. Similarly, the second seal portion 60B is configured by attaching waterproof members 65 and 66 to the second sleeve 62. The first sleeve 61 and the second sleeve 62 are cylindrical insulators molded from an insulating material such as synthetic resin, and have an insulating function that prevents electricity passed through the torch barrel 20 from flowing to the nozzle 16 via the outer cylindrical body 52. The waterproof members 63, 64, 65, and 66 are O-rings made of synthetic resin, rubber, or the like, and have the function of preventing the cooling water supplied to the interior portion 55 inside the outer cylinder body 52 from leaking outside the outer cylinder body 52.

[0061] The first sleeve 61 is a tubular body having a cylindrical shape, and is disposed on the front end side of the interior portion 55 . The rear end of the first sleeve 61 has a locking portion 61 a which is an annular protrusion that protrudes radially inward so as to lock onto a step formed in the front part of the connecting portion 39 .

[0062] A ring-shaped waterproof member 63 is provided in an annular groove formed on the outer circumferential surface of the first sleeve 61. The waterproof member 63 is in close contact with the inner circumferential surface of the outer cylinder body 52. ​​In other words, the waterproof member 63 is provided so as to be sandwiched in the radial direction between the first sleeve 61 and the outer cylinder body 52, which are formed from an insulating material. A ring-shaped waterproof member 64 is provided in an annular groove formed on the outer peripheral surface of the front part of the connection portion 39 of the tip body 30 which abuts against the inner peripheral surface of the first sleeve 61. The waterproof member 64 is provided so as to be sandwiched between the first sleeve 61 and the connection portion 39 of the tip body 30 in the radial direction. As described above, the first sleeve 61 and the waterproof member 63 form a first seal portion 60A that seals between the inner peripheral surface of the front end side of the outer cylinder body 52 and the outer peripheral surface of the front side of the connection portion 39 of the tip body 30. This configuration can be seen in Figures 5 and 6.

[0063] The first sleeve 61 is attached and fixed with its outer peripheral surface inserted into the front end side of the outer tube body 52, and by fastening the tip body 30 to the male thread portion 21b of the inner tube exposed portion 21a, the inner peripheral surface of the first sleeve 61 is brought into close contact with the connection portion 39 of the tip body 30.

[0064] The second sleeve 62 is a tubular body having a cylindrical shape, and is disposed on the rear end side of the interior portion 55 . The rear end of the second sleeve 62 has a flange portion 62 a which is an annular convex portion that protrudes radially outward so as to receive the rear end surface of the outer tubular body 52 .

[0065] A ring-shaped waterproof member 65 is provided in an annular groove formed on the outer circumferential surface of the front part of the second sleeve 62. The waterproof member 65 is provided so as to be sandwiched between the outer circumferential surface of the second sleeve 62 and the inner circumferential surface of the outer cylinder body 52 in the radial direction. A ring-shaped waterproof member 66 is provided in an annular groove formed on the inner circumferential surface of the front part of the second sleeve 62. The waterproof member 66 is positioned so as to be sandwiched radially between the inner circumferential surface of the second sleeve 62 and the outer circumferential surface of the barrel section 22. As described above, the second sleeve 62 and the waterproof members 65, 66 form the second seal portion 60B, which seals between the inner circumferential surface of the rear end of the outer tubular body 52 and the outer circumferential surface of the front part of the barrel portion 22. This configuration can be seen in Figures 5 and 6.

[0066] The second sleeve 62 is attached and fixed with its outer circumferential surface inserted into the rear end side of the external cylinder body 52, and the flange portion 62a is engaged with the rear end of the external cylinder body 52. ​​Furthermore, by fastening the external cylinder body 52 to the nut member 51, the inner circumferential surface of the second sleeve 62 is brought into close contact with the outer circumferential surface of the barrel outer cylinder portion 22.

[0067] (Action and Effects) The above-mentioned welding torch 10 is cooled through a supply process in which cooling water supplied from the cooling water supply unit 12 to the supply passage 23 is supplied to the interior portion 55; a cooling process in which the connection portion 39 of the tip body 30 is directly water-cooled by the cooling water supplied by the interior portion 55, and the entire tip body 30 is cooled via this connection portion 39 and the nozzle 16 is water-cooled via the outer cylinder 52; and a discharge process in which the cooling water that has been circulated through the interior portion 55 and has been water-cooled is discharged from the recovery passage 24. The cooling water supplied to the interior portion 55 comes into contact with the outer surface of the connection portion 39 and can directly cool it, so that the cooling efficiency of the entire tip body 30, which becomes hot during arc welding, is improved compared to the conventional art. In addition, since the connection portion 39 extending rearward from the rear end of the tip body 30 provides a highly versatile structure that improves cooling efficiency, the tip body 30 itself can be provided with a special structure such as a forced current mechanism.

[0068] Also, the rear side of the nozzle 16 is attached to the outer cylinder 52 so as to cover the outer peripheral surface of the front half of the outer cylinder 52. In other words, the nozzle 16 is arranged to cover from the vicinity of the supply side opening 23a and the recovery side opening 24a to the front end side of the interior part 55 via the male thread part 52a at the front part of the outer cylinder 52. Therefore, the cooling water supplied to the interior part 55 can efficiently cool the rear part of the nozzle 16 via the front part of the outer cylinder 52, which has high thermal conductivity. This configuration may be seen in FIG. 5. As described above, the cooling efficiency of the welding torch 10 is improved with a simple and low-cost configuration.

[0069] Next, another example of the chip body 30 will be described with reference to Fig. 8, focusing on differences from the above embodiment. Fig. 8 is a cross-sectional view showing the chip body 30 of the other example.

[0070] The tip body 30 has a front body portion 30A and a rear body portion 30B. The front body portion 30A is formed with a female thread portion 35 at the axial tip end to which the contact tip is fastened, a retaining portion 38 that constitutes the wire pressing portion 33, and a female thread portion 72 at the axial base end to which the rear body portion 30B is fastened. The rear body portion 30B has a male thread portion 71 at its axial tip end to which the female thread portion 72 of the front body portion 30A is fastened, and a connection portion 39 at its axial base end to which the male thread portion 21b of the inner tube exposed portion 21a is fastened.

[0071] According to the tip body 30 having this configuration, it is possible to replace only the body front portion 30A while leaving the body rear portion 30B fastened to the inner cylinder exposed portion 21a. In other words, since the tip body 30 is arranged to seal the gap between the outer peripheral surface of the connection portion 39 and the inner peripheral surface of the outer cylinder body 52, it is possible to replace only the front body portion 30A without removing the first sleeve 61, which is relatively difficult to attach and detach, thereby improving maintainability.

[0072] The present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known technologies, and these are included in the scope of protection sought.

[0073] As described above, the present specification discloses the following: (1) A welding torch used in gas-shielded arc welding, The welding torch is A torch barrel portion to which a tip body is attached at the tip side; an outer cylinder body attached to the torch barrel portion so as to exteriorly surround the torch barrel portion; Equipped with The torch barrel portion has a barrel outer cylinder and a barrel inner cylinder inserted into the barrel outer cylinder, A supply passage for supplying cooling water between the inner barrel and the outer barrel, and a recovery passage for recovering cooling water between the inner barrel and the outer barrel are formed on the outer circumferential surface of the barrel. The barrel inner cylinder has an exposed portion extending toward the axial tip side of the barrel outer cylinder, A supply side opening at an axial tip end side of the supply path and a recovery side opening at an axial tip end side of the recovery path are formed on a base end side of an outer circumferential surface of the inner cylinder exposed portion, a connecting portion to which an axial tip end side of the inner cylinder exposed portion is connected is provided on a rear end side of the tip body, The connection portion is formed so as to cover an outer circumferential side of the inner cylinder exposed portion, the outer cylinder body has an interior portion that interiorly accommodates at least the connection portion, the supply side opening, and the recovery side opening, The interior portion is provided with a seal portion that seals between the external cylinder body and the tip body, and between the external cylinder body and the gun barrel. Welding torch. With this configuration, the tip body is simply formed to cover the connection portion at the axial tip side of the barrel's inner cylindrical portion, and the axial rear end side of the tip body can be cooled with cooling water. This means that the tip body can be cooled efficiently with a simple, low-cost configuration, and is also highly versatile.

[0074] (2) The sealing portion has at least an insulator and a waterproof member, The waterproof member seals between an outer peripheral surface of the insulator and the outer cylinder body arranged radially outside the insulator, or between an inner peripheral surface of the insulator and the tip body or the gun barrel arranged radially inside the insulator. The welding torch described in (1). According to this configuration, since the insulators are disposed in the front and rear seal portions, insulation is achieved more reliably.

[0075] (3) A cylindrical attachment body is inserted into the torch barrel portion and its axial movement toward the tip side is restricted by a restricting portion provided on the torch barrel portion, The outer cylinder is fastened to the mounting body at a position on the axial tip side of the restricting portion, so that the axial movement of the outer cylinder is restricted while the outer cylinder is sheathed to the tip body and the torch barrel portion. A welding torch as described in (1) or (2). According to this configuration, the outer cylinder body can be fixed at a predetermined mounting position by fastening it to the mounting body, which makes assembly work easier.

[0076] (4) The tip body has an eccentric guide portion having a first inner diameter, and a wire pressing portion that radially eccentrically displaces the welding wire inserted into the eccentric guide portion, a contact tip connected to the axial tip side of the tip body, the contact tip being formed along the axial direction from a tip opening formed at the tip to a rear opening, and having a guide hole for guiding the welding wire; The guide hole has a second inner diameter smaller than the first inner diameter. A welding torch according to any one of (1) to (3). According to this configuration, by arranging the wire pressing portion on the tip body, which utilizes the reaction force of the bending rigidity of the welding wire to stably contact the welding wire with the contact tip, the entire welding torch can be made compact, and the configuration of the contact tip, which is replaced relatively frequently, can be simplified, thereby keeping costs low.

[0077] (5) A base end guide portion having a third inner diameter is provided on a base end side of the eccentric guide portion, The third inner diameter is smaller than the first inner diameter and larger than the second inner diameter. (4) A welding torch as described in (1). According to this configuration, the eccentric welding wire can be deformed into a mountain shape by the wire pressing portion, so that the force of contacting the welding wire with the contact tip side becomes more stable.

[0078] (6) The wire pressing portion has at least a pressing member that contacts the welding wire and an elastic member that presses the pressing member against the welding wire, The pressing member is a spherical member, The elastic member is a leaf spring member. (4) A welding torch as described in (1). According to this configuration, the pressing member pressed against the welding wire is formed spherically, so that the wire pressing portion can radially decenter the welding wire while preventing the force required to feed the welding wire out of the opening of the contact tip from becoming greater than necessary.

[0079] (7) The tip body has a body rear portion in which the connection portion is provided, and a body front portion detachably attached to a front end side of the body rear portion. A welding torch according to any one of (1) to (6). According to this configuration, the front body portion at the front side of the tip body can be replaced without removing the seal portion, improving maintainability.

[0080] (8) providing a metallic orifice in the tip body; A welding torch according to any one of (1) to (7). According to this configuration, the thermal conductivity is improved, and therefore the cooling performance is improved.

[0081] (9) The orifice has a cylindrical cover body that extends toward a tip end in an axial direction and covers an outer peripheral surface of the tip body. (8) A welding torch as described in (8). According to this configuration, the cross-sectional area of ​​the orifice for heat conduction is increased, which contributes to improving the cooling efficiency.

[0082] (10) A method for cooling a welding torch used in gas-shielded arc welding, comprising the steps of: The welding torch is A torch barrel portion to which a tip body is attached at the tip side; an outer cylinder body attached to the torch barrel portion so as to exteriorly surround the torch barrel portion; Equipped with The torch barrel portion has a barrel outer cylinder and a barrel inner cylinder inserted into the barrel outer cylinder, A supply passage for supplying cooling water between the inner barrel and the outer barrel, and a recovery passage for recovering cooling water between the inner barrel and the outer barrel are formed on the outer circumferential surface of the barrel. The barrel inner cylinder has an exposed portion extending toward the axial tip side of the barrel outer cylinder, A supply side opening at an axial tip end side of the supply path and a recovery side opening at an axial tip end side of the recovery path are formed on a base end side of an outer circumferential surface of the inner cylinder exposed portion, a connection portion for connecting to the tip body is provided on the axial end side of the exposed portion of the inner cylinder; the connecting portion is connected such that the tip body covers an outer circumferential side of the exposed portion of the inner cylinder, the outer cylinder body has an interior portion that interiorly accommodates at least the connection portion, the supply side opening, and the recovery side opening, The internal part is provided with a seal part for sealing between the external cylinder body and the tip body, and between the external cylinder body and the gun barrel, a supply step in which cooling water is supplied from the supply side opening to the interior part; a cooling step of cooling the connection portion with the cooling water; a recovery step in which the cooling water having cooled the interior portion is recovered from the recovery side opening; having How to cool a welding torch. With this configuration, the tip body is simply formed to cover the connection portion at the axial tip side of the barrel's inner cylindrical portion, and the axial rear end side of the tip body can be cooled with cooling water. This means that the tip body can be cooled efficiently with a simple, low-cost configuration, and is also highly versatile. [Explanation of symbols]

[0083] 1. Welding robot 2 Wire Pack 3 Torch Cable 4 Wire feeder 5 Welding power source 6 Manipulator 10. Welding Torch 11 Electrical fittings 12 Cooling water supply section 13 Conduit Tube 14 Orifice 14a Through hole 14b Flange part 15 Cover body 16 Nozzles 16a Female thread 16b Stepped section 17 Insulation ring 20 Torch barrel 21 Gun barrel inner cylinder 21a Inner cylinder exposed part 21b Male thread 21c,45a Slope part 22 Gun barrel outer tube 23 Supply route 23a Supply side opening 24 Recovery Route 24a Collection side opening 30 Tip Body 30a through hole 30A Front body 30B Rear body 31 Eccentric guide part 32 Base end guide part 33 Wire pressing part 34 Female thread 35 Female thread 35a Tapered section 36 Pressing member 37 Pressing member 37A Connection part 37B,37C Holding part 37B1 Contact surface 37B2 Locking part 38 Holding part 38A Groove 38B Notched surface 38C through hole 39 Connection 39a Tapered section 40 Contact Tip 42 Guide hole 42a Tip opening 42b Rear end opening 43 Tapered section 44 Connecting part 45 Male thread 50 Nozzle attachment mechanism 51 Nut member (mounting body) 51a Female thread 51b bottom 51c Insertion hole 52 External cylinder 52a Male thread 52b Male thread 53 Regulating member (regulating part) 54 Materials 55 Interior 60 Seal part 60A First Seal Part 60B Second seal part 61 First sleeve (insulator) 61a Locking part 62 Second sleeve (insulator) 62a Flange 63, 64, 65, 66 Waterproofing materials 71 Male thread 72 Female thread X0 Tip contact position X1 1st contact position X2 2nd contact position X3 3rd contact position R1 First inner diameter R2 Second inner diameter R3 Third inner diameter

Claims

1. A welding torch for use in gas shielded arc welding, The welding torch is A torch barrel portion to which a tip body is attached at the tip side; an outer cylinder body attached to the torch barrel portion so as to exteriorly surround the torch barrel portion; Equipped with The torch barrel portion has a barrel outer cylinder and a barrel inner cylinder inserted into the barrel outer cylinder, A supply passage for supplying cooling water between the inner barrel and the outer barrel, and a recovery passage for recovering cooling water between the inner barrel and the outer barrel are formed on the outer circumferential surface of the barrel. The barrel inner cylinder has an exposed portion extending toward the axial tip side of the barrel outer cylinder, A supply side opening at an axial tip end side of the supply passage and a recovery side opening at an axial tip end side of the recovery passage are formed on a base end side of an outer circumferential surface of the inner cylinder exposed portion, a connecting portion to which an axial tip end side of the inner cylinder exposed portion is connected is provided on a rear end side of the tip body, The connection portion is formed so as to cover an outer circumferential side of the inner cylinder exposed portion, the outer cylinder body has an interior portion that interiorly accommodates at least the connection portion, the supply side opening, and the recovery side opening, The interior portion is provided with a seal portion that seals between the external cylinder body and the tip body, and between the external cylinder body and the gun barrel. Welding torch.

2. The seal portion has at least an insulator and a waterproof member, The waterproof member seals between an outer peripheral surface of the insulator and the outer cylinder body arranged radially outside the insulator, or between an inner peripheral surface of the insulator and the tip body or the gun barrel arranged radially inside the insulator. The welding torch of claim 1.

3. a cylindrical attachment body that is inserted into the torch barrel and whose axial movement toward the tip side is restricted by a restricting portion provided on the torch barrel; The outer cylinder is fastened to the mounting body at a position on the axial tip side of the restricting portion, so that the axial movement of the outer cylinder is restricted while the outer cylinder is sheathed to the tip body and the torch barrel portion. The welding torch of claim 1.

4. the tip body has an eccentric guide portion having a first inner diameter, and a wire pressing portion that radially eccentrically displaces a welding wire inserted into the eccentric guide portion, a contact tip connected to the axial tip side of the tip body, the contact tip being formed along the axial direction from a tip opening formed at the tip to a rear opening, and having a guide hole for guiding the welding wire; The guide hole has a second inner diameter smaller than the first inner diameter. The welding torch according to any one of claims 1 to 3.

5. a base end guide portion having a third inner diameter is provided on a base end side of the eccentric guide portion, The third inner diameter is smaller than the first inner diameter and larger than the second inner diameter. The welding torch of claim 4.

6. the wire pressing portion has at least a pressing member that contacts the welding wire and an elastic member that presses the pressing member against the welding wire, The pressing member is a spherical member, The elastic member is a leaf spring member. The welding torch of claim 4.

7. the tip body has a body rear portion in which the connection portion is provided, and a body front portion detachably attached to a front end side of the body rear portion. The welding torch of claim 1.

8. providing a metallic orifice in the tip body; The welding torch of claim 1.

9. the orifice extends toward a tip end in an axial direction and has a cylindrical cover body that covers an outer peripheral surface of the tip body; The welding torch of claim 8.

10. A method for cooling a welding torch used in gas shielded arc welding, comprising: The welding torch is A torch barrel portion to which a tip body is attached at the tip side; an outer cylinder body attached to the torch barrel portion so as to exteriorly surround the torch barrel portion; Equipped with The torch barrel portion has a barrel outer cylinder and a barrel inner cylinder inserted into the barrel outer cylinder, A supply passage for supplying cooling water between the inner barrel and the outer barrel, and a recovery passage for recovering cooling water between the inner barrel and the outer barrel are formed on the outer circumferential surface of the barrel. The barrel inner cylinder has an exposed portion extending toward the axial tip side of the barrel outer cylinder, A supply side opening at an axial tip end side of the supply path and a recovery side opening at an axial tip end side of the recovery path are formed on a base end side of an outer circumferential surface of the inner cylinder exposed portion, a connection portion for connecting to the tip body is provided on the axial end side of the exposed portion of the inner cylinder; the connecting portion is connected such that the tip body covers an outer circumferential side of the exposed portion of the inner cylinder, the outer cylinder body has an interior portion that interiorly accommodates at least the connection portion, the supply side opening, and the recovery side opening, The internal part is provided with a seal part for sealing between the external cylinder body and the tip body, and between the external cylinder body and the gun barrel, a supply step in which cooling water is supplied from the supply side opening to the interior part; a cooling step of cooling the connection portion with the cooling water; a recovery step in which the cooling water that has cooled the interior portion is recovered from the recovery side opening; having How to cool a welding torch.

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