Welding torch and method for cooling welding torch

Abstract

The invention provides a welding torch and a method for cooling the welding torch, wherein the welding torch can be efficiently cooled by using a simple and low-cost structure. The welding torch is provided with a welding torch body part to which the contact tip member is mounted, and an exterior body, the welding torch body part has a body outer cylinder and a body inner cylinder, a cooling water supply path and a cooling water recovery path are formed on the outer peripheral surface of the body inner cylinder, and the body inner cylinder has an inner cylinder exposed part. A supply-side opening part and a recovery-side opening part are formed on the base end side of the outer peripheral surface of the inner cylinder exposed part, and a connection part connected to the contact tip main body is provided on the axial front end side of the inner cylinder exposed part, and the connection part is connected so that the contact tip main body covers the outer peripheral side of the inner cylinder exposed part. At least a connecting part, a supply side opening part and a recovery side opening part are arranged on the inner side of the outer cylinder body, and sealing parts for sealing the space between the outer cylinder body and the contact tip main body and the space between the outer cylinder body and the gun body outer cylinder are arranged.

Description

Technical Field

[0001] The invention relates to a welding torch and a cooling method of the welding torch. Background Art

[0002] Generally, when the welding current applied during welding increases, the radiant heat of the arc increases, so the temperature of the welding torch itself rises. In particular, the temperature of the conductive tip and the nozzle on the front end side of the welding torch close to the arc generation position increases significantly. When the temperature of the welding torch increases, there is a possibility that the wear amount of the conductive tip and the amount of spatter attached to the nozzle increase. In addition, there is a possibility that the fastening connection portion connecting the conductive tip and the conductive tip body is sintered. Therefore, in the past, a structure in which a water cooling mechanism is provided on the welding torch to efficiently cool the welding torch has been disclosed.

[0003] Patent Document 1 describes a welding torch in which cooling water is circulated to the axial front end side of the welding torch by forming a forward water passage and a return water passage for cooling inside a contact tip body and a nozzle.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2020-93270

[0007] The welding torch described in Patent Document 1 can circulate cooling water to the axial front end side of the contact tip body and the nozzle, but the structures of the contact tip body and the nozzle, which are consumables, become complicated and thus the cost becomes high. In addition, since a cavity for cooling is formed inside the contact tip body, the contact tip body cannot be processed for setting other special mechanisms, and there is a problem that the versatility is also reduced. Summary of the invention

[0008] Problems to be solved by the invention

[0009] The present invention has been made in view of the above-mentioned situation, and an object of the present invention is to provide a welding torch and a cooling method of the welding torch which can be cooled efficiently with a simple and low-cost structure and have high versatility.

[0010] Solutions to Solve Problems

[0011] The above-mentioned object of the present invention is achieved by the following structure.

[0012] (1) A welding torch for gas shielded arc welding, wherein:

[0013] The welding torch has:

[0014] A welding torch body having a contact tip body mounted on the front end side thereof; and

[0015] The outer cylinder is mounted on the side of the welding torch body in a manner of being externally mounted on the welding torch body.

[0016] The welding torch body has an outer barrel and an inner barrel inserted into the outer barrel.

[0017] A supply path for supplying cooling water between the gun body inner tube and the gun body outer tube and a recovery path for recovering cooling water between the gun body outer tube are formed on the outer peripheral surface of the gun body inner tube.

[0018] The gun body inner tube has an inner tube exposed portion extending toward the axial front end side from the gun body outer tube,

[0019] A supply side opening at the axial front end side of the supply path and a recovery side opening at the axial front end side of the recovery path are formed on the base end side of the outer peripheral surface of the inner tube exposed portion.

[0020] A connection portion is provided on the rear end side of the conductive tip body to connect the axial front end side of the inner tube exposed portion.

[0021] The connecting portion is formed so as to cover the outer peripheral side of the exposed portion of the inner tube.

[0022] The outer cylinder has an interior portion that houses at least the connection portion, the supply-side opening, and the recovery-side opening.

[0023] The inner part is provided with a sealing part for sealing the outer cylinder and the conductive nozzle body and the outer cylinder and the gun body outer cylinder.

[0024] (2) The welding torch according to (1), wherein:

[0025] The sealing portion at least comprises an insulator and a waterproof member.

[0026] The waterproof member seals the outer circumferential surface of the insulator and the outer cylinder arranged radially outside the insulator, or the inner circumferential surface of the insulator and the contact tip body or the gun body outer cylinder arranged radially inside the insulator.

[0027] (3) The welding torch according to (1), wherein:

[0028] The welding torch has a cylindrical mounting body which is inserted through the welding torch body and whose axial movement toward the front end side is restricted by a restricting portion provided on the welding torch body.

[0029] The outer cylindrical body is fastened to the mounting body at a position closer to the axial front end side than the restricting portion, and thus the outer cylindrical body is restricted from moving in the axial direction in a state of being externally mounted on the contact tip body and the torch barrel.

[0030] (4) The welding torch according to any one of (1) to (3), wherein:

[0031] The contact tip body comprises: an eccentric guide portion having a first inner diameter; and a welding wire pressing portion which makes the welding wire inserted into the eccentric guide portion eccentric in the radial direction.

[0032] The conductive tip connected to the axial front end side of the conductive tip body is provided with a guide hole formed along the axial direction from the front end opening formed at the front end to the rear end opening and guiding the welding wire.

[0033] The guide hole has a second inner diameter that is smaller than the first inner diameter.

[0034] (5) The welding torch according to (4), wherein:

[0035] A base end guide portion is provided on the base end side of the eccentric guide portion, and the base end guide portion has a third inner diameter.

[0036] The third inner diameter is smaller in diameter than the first inner diameter, and is larger in diameter than the second inner diameter.

[0037] (6) The welding torch according to (4), wherein:

[0038] The welding wire pressing portion at least comprises a pressing member in contact with the welding wire and an elastic member for pressing the pressing member toward the welding wire.

[0039] The pressing member is a spherical member.

[0040] The elastic member is configured as a leaf spring-shaped member.

[0041] (7) The welding torch according to (1), wherein:

[0042] The contact tip body includes a body rear portion on which the connection portion is provided and a body front portion detachably mounted on the front end side of the body rear portion.

[0043] (8) The welding torch according to (1), wherein:

[0044] A metallic throttling portion is provided on the conductive nozzle body.

[0045] (9) The welding torch according to (8), wherein:

[0046] The throttle portion includes a cylindrical cover extending toward the front end side in the axial direction and covering the outer peripheral surface of the contact tip body.

[0047] (10) A method for cooling a welding torch used for gas shielded arc welding, wherein:

[0048] The welding torch has:

[0049] A welding torch body having a contact tip body mounted on the front end side thereof; and

[0050] The outer cylinder is mounted on the side of the welding torch body in a manner of being externally mounted on the welding torch body.

[0051] The welding torch body has an outer barrel and an inner barrel inserted into the outer barrel.

[0052] A supply path for supplying cooling water between the gun body inner tube and the gun body outer tube and a recovery path for recovering cooling water between the gun body outer tube are formed on the outer peripheral surface of the gun body inner tube.

[0053] The gun body inner tube has an inner tube exposed portion extending toward the axial front end side from the gun body outer tube,

[0054] A supply side opening at the axial front end side of the supply path and a recovery side opening at the axial front end side of the recovery path are formed on the base end side of the outer peripheral surface of the inner tube exposed portion.

[0055] A connection portion connected to the conductive tip body is provided on the axial front end side of the inner tube exposed portion.

[0056] The connecting portion is connected in such a manner that the contact tip body covers the outer peripheral side of the inner cylinder exposed portion.

[0057] The outer cylinder has an interior portion that houses at least the connection portion, the supply-side opening, and the recovery-side opening.

[0058] The inner part is provided with a sealing part for sealing the outer cylinder and the conductive nozzle body and the outer cylinder and the gun body outer cylinder.

[0059] The cooling method of the welding torch comprises:

[0060] a supplying step of supplying the cooling water supplied from the supply-side opening to the interior portion;

[0061] a cooling step of cooling the connection portion using the cooling water; and

[0062] The recovery step is to recover the cooling water having cooled the interior portion from the recovery-side opening.

[0063] Effects of the Invention

[0064] According to the present invention, the contact tip body can be efficiently cooled by a simple and low-cost structure in which the rear end of the contact tip body is extended to form a connection portion covering the axial front end side of the inner tube of the gun body. In addition, the connection portion can be applied to the contact tip body in which the axial mid-portion of the contact tip body is specially processed, so the versatility is also improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a schematic side view of a welding robot using a welding torch to which the present invention is applied.

[0066] Figure 2 It is a top view showing a welding torch to which the present invention is applied.

[0067] Figure 3 It is a side view showing a welding torch to which the present invention is applied.

[0068] Figure 4 This is an exploded perspective view of a welding torch to which the present invention is applied.

[0069] Figure 5 It is an AA cross-sectional view of the welding torch showing the circulation path of cooling water.

[0070] Figure 6 It is a BB cross-sectional view of the welding torch showing the forced energization mechanism.

[0071] Figure 7 It is a cross-sectional view showing a wire pressing portion.

[0072] Figure 8 is a central cross-sectional view showing another embodiment of the contact tip body.

[0073] Description of Reference Numerals

[0074] 1. Welding Robot

[0075] 2 welding wire packaging barrel

[0076] 3 torch cable

[0077] 4Wire feeding device

[0078] 5. Welding power supply

[0079] 6. Robot

[0080] 10 welding torch

[0081] 11Electrified metal parts

[0082] 12Cooling water supply unit

[0083] 13 Catheter

[0084] 14. Throttle

[0085] 14a Through hole

[0086] 14b flange

[0087] 15. Body

[0088] 16 Nozzles

[0089] 16a Internal thread

[0090] 16b Step

[0091] 17 Insulation ring

[0092] 20 welding torch body

[0093] 21 Gun barrel inner part

[0094] 21a Inner tube exposed part

[0095] 21b External thread

[0096] 21c, 45a inclined portion

[0097] 22 Gun barrel outer part

[0098] 23 Supply Road

[0099] 23a Supply side opening

[0100] 24 Recycling Road

[0101] 24a Recovery side opening

[0102] 30 contact nozzle body

[0103] 30a through hole

[0104] 30A Main body front

[0105] 30B Main body rear

[0106] 31 Eccentric guide

[0107] 32 base end guide

[0108] 33 welding wire pressing part

[0109] 34 Internal thread

[0110] 35 Internal thread

[0111] 35a cone

[0112] 36 Pressing member

[0113] 37 Force-applying member

[0114] 37A Connection

[0115] 37B, 37C clamping part

[0116] 37B1 abutment surface

[0117] 37B2 stopper

[0118] 38. Maintaining part

[0119] 38A slot

[0120] 38B resection surface

[0121] 38C through hole

[0122] 39Connection

[0123] 39a cone

[0124] 40 contact tip

[0125] 42 guide holes

[0126] 42a Front opening

[0127] 42b Rear opening

[0128] 43 cone

[0129] 44 connection part

[0130] 45 external thread

[0131] 50 Nozzle installation mechanism

[0132] 51 Nut component (installation body)

[0133] 51a Internal thread

[0134] 51b bottom

[0135] 51c through hole

[0136] 52 outer cylinder

[0137] 52a External thread

[0138] 52b External thread

[0139] 53 limiting member (limiting part)

[0140] 54 components

[0141] 55 Interior Department

[0142] 60 Sealing part

[0143] 60A first sealing part

[0144] 60B Second sealing part

[0145] 61 first sleeve (insulator)

[0146] 61a locking portion

[0147] 62 second sleeve (insulator)

[0148] 62a Flange

[0149] 63, 64, 65, 66 waterproof components

[0150] 71 External thread

[0151] 72 internal thread

[0152] X0 front contact position

[0153] X1 first contact position

[0154] X2 second contact position

[0155] X3 third contact position

[0156] R1 first inner diameter

[0157] R2 Second inner diameter

[0158] R3 third inner diameter. DETAILED DESCRIPTION

[0159] Hereinafter, the structure of the welding torch to which the present invention is applied will be described with reference to the drawings. It should be noted that each drawing is prepared for explaining the present invention, and the embodiment of the present invention is not limited to the contents shown in the drawings.

[0160] First, in order to understand the overall situation of the welding torch to which the present invention is applied, based on Figure 1 A welding robot using a welding torch will be described. Figure 1 This is a schematic side view of a welding robot using the welding torch according to the embodiment.

[0161] Welding robot 1 Figure 1 As shown, it includes a welding wire packaging barrel 2, a welding torch cable 3, a welding wire feeding device 4, a welding power source 5, a manipulator 6 and a welding torch 10. It should be noted that, Figure 1 The reference symbol A in FIG. 8 is a base material to be welded.

[0162] Welding wire packaging barrel 2 Figure 1 As shown, it is a supply source of welding wire W, and stores a predetermined amount of welding wire W. As welding wire W, for example, copper-plated welding wire, copper-free welding wire, etc. can be used.

[0163] The welding torch cable 3 supplies welding current supplied from the welding power source 5, welding wire W stored in the welding wire packaging barrel 2, and shielding gas supplied from a shielding gas storage device (not shown) to the welding torch 10. One end of the welding torch cable 3 is connected to the welding wire feeding device 4, and the other end is connected to the welding torch 10.

[0164] The wire feeding device 4 unwinds the welding wire W via the torch cable 3 using a roller or the like and feeds the welding wire W to the welding torch 10. By providing the welding wire feeding device 4, the welding wire W is automatically supplied to the welding torch 10.

[0165] The welding power source 5 is a supply source of welding current, and supplies the welding current to the welding torch 10 via the wire feeder 4 and the torch cable 3 .

[0166] The robot 6 is a multi-joint robot having a welding torch 10 attached to the front end thereof, and its operation is controlled by a robot control device (not shown).

[0167] In the following embodiments, the extending direction of the welding torch 10 is referred to as the axial direction. With respect to the axial direction of the welding torch 10, the direction in which the welding wire W is released is referred to as the front or the front end side. With respect to the axial direction of the welding torch 10, the direction opposite to the release direction of the welding wire W is referred to as the rear or the base end side.

[0168] Next, based on Figure 2 to Figure 7 The structure of the welding torch 10 according to the present embodiment will be described. Figure 2-3 1 is a top view and a side view showing a welding torch to which the present invention is applied, Figure 4 is an exploded perspective view of a welding torch to which the present invention is applied. Figure 5 is a cross-sectional view of a welding torch showing a circulation path of cooling water. Figure 6 is a cross-sectional view of a welding torch showing a forced energization mechanism, Figure 7 FIG. 2 is a cross-sectional view showing the welding wire pressing portion. Figure 5 In the figure, the guide tube 13 and the welding wire W are omitted.

[0169] The welding torch 10 automatically feeds the welding wire W into the cylinder and performs arc welding using the welding wire W. Figure 2 As shown, the welding torch 10 is equipped with a current-carrying metal fitting 11 and a cooling water supply unit 12 .

[0170] The current-carrying metal fitting 11 is used to detect contact between the nozzle 16 and the base material A by applying a voltage to the nozzle. The cooling water supply unit 12 is used to circulate and supply cooling water to the welding torch 10 .

[0171] (Welding Torch 10)

[0172] Welding torch 10 Figure 4 As shown, the welding torch includes a welding torch body 20 , a throttle portion 14 , a contact tip body 30 , a contact tip 40 , a nozzle mounting mechanism 50 , a nozzle 16 , and a sleeve-shaped sealing portion 60 .

[0173] The contact tip body 30 has a forced energization mechanism for eccentrically displacing the welding wire W as an example of a special mechanism provided by processing the axial midway portion.

[0174] The nozzle mounting mechanism 50 includes a nut member 51 and an outer cylinder 52 , and detachably mounts the nozzle 16 on the front end side of the torch barrel 20 .

[0175] The sealing portion 60 includes a first sealing portion 60A and a second sealing portion 60B, and is inserted into the outer cylinder 52 .

[0176] (Torch body 20)

[0177] The welding torch body 20 includes: a body inner tube 21 having a cylindrical shape; and a body outer tube 22 into which the body inner tube 21 is inserted. The body inner tube 21 and the body outer tube 22 are integrated in a state where the outer surface of the body inner tube 21 and the inner surface of the body outer tube 22 are fitted. It should be noted that the body inner tube 21 is formed longer than the body outer tube 22 in a manner that it protrudes from the front end and the rear end of the body outer tube 22 in the axial direction.

[0178] A guide tube 13 for guiding welding wire W supplied from the torch cable 3 is inserted into the gun body inner tube portion 21. The rear side of the gun body inner tube portion 21 is connected to the torch cable 3, and the gun body inner tube portion 21 is provided with a contact tip body 30 extending toward the axial front end side.

[0179] The gun barrel inner tube portion 21 has an inner tube exposed portion 21 a extending toward the front end side in the axial direction from the gun barrel outer tube portion 22 .

[0180] Between the inner barrel portion 21 of the gun body and the outer barrel portion 22 of the gun body, as shown in FIG. Figure 4 as well as Figure 5 As shown, a pair of cutout surfaces are formed along the length direction on the outer peripheral surface of the gun body inner tube portion 21 to form a supply path 23 for supplying cooling water and a recovery path 24 for recovering cooling water.

[0181] 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 outer tube portion 22 of the gun body, a supply side opening portion 23a which is open at the axial front end side of the supply path 23 and a recovery side opening portion 24a which is open at the axial front end side of the recovery path 24 are formed.

[0182] In addition, the inner cylinder exposed portion 21 a is provided with an external thread portion 21 b for fastening and connecting the contact tip body 30 to the axially distal end sides of the supply-side opening 23 a and the recovery-side opening 24 a .

[0183] Furthermore, at the front end portion of the inner cylinder exposed portion 21 a , an annular inclined portion 21 c that contacts the contact tip body 30 is formed by annularly cutting away the outer peripheral edge.

[0184] A supply side connection portion and a recovery side connection portion (not shown) connected to the cooling water supply portion 12 are formed on the axial base end side of the supply passage 23 and the recovery passage 24. The cooling water is supplied to the supply passage 23 and recovered from the recovery passage 24 by the cooling water supply portion 12 connected to the supply side connection portion and the recovery side connection portion.

[0185] (Throttling section 14)

[0186] The throttle portion 14 includes a mechanism for rectifying the flow of the shielding gas.

[0187] The throttle portion 14 has a plurality of through holes 14a for the shielding gas to flow formed at equal intervals in the circumferential direction at a position close to the through hole 30a formed in the contact tip body 30 when the throttle portion 14 is assembled to the contact tip body 30. Thus, the throttle portion 14 smoothly guides the shielding gas flowing into the inner circumference to the through holes 14a, and can prevent the shielding gas from causing turbulence.

[0188] A cover body 15 formed by molding a metal member having high thermal conductivity into a cylindrical shape is integrally mounted and fixed to the front end side of the throttle portion 14 .

[0189] The throttle portion 14 is assembled at a predetermined position of the contact tip body 30, so that the cover 15 covers the entire circumference of the front portion of the contact tip body 30. As a result, the thickness of the cover 15 (or the throttle portion 14) is increased on the basis of the thickness of the contact tip body 30, thereby increasing the heat conduction cross-sectional area and improving the cooling performance. Figure 5 as well as Figure 6 As the metal with high thermal conductivity, there can be mentioned Cu, Ag, or an alloy mainly containing either Cu or Ag, but brass is most preferred from the viewpoint of cost.

[0190] The throttle portion 14 has a flange portion 14b on the rear end side.

[0191] The front surface of the flange portion 14b is locked to a step portion 16b formed on the inner peripheral surface of the nozzle 16 via an insulating ring 17 inserted from the front of the throttle portion 14, thereby restricting the throttle portion 14 from sliding forward from a predetermined position.

[0192] This can also reliably prevent the metal throttle portion 14 and cover 15 from contacting the nozzle 16 and causing electricity to flow. Figures 4 to 6 Better.

[0193] (Conductive tip body 30)

[0194] The contact tip body 30 is a cylindrical member extending in the axial direction, and includes a mechanism for supporting the throttle portion 14 and the contact tip 40. The contact tip body 30 is formed of a material having electrical conductivity such as metal.

[0195] The cylindrical throttle portion 14 is inserted from the front end of the contact tip body 30. In addition, in the contact tip body 30, a plurality of through holes 30a for the shielding gas to flow are formed at equal intervals along the circumferential direction at the portion where the throttle portion 14 is mounted. Figure 4 Better.

[0196] The tip body 30 has an internal thread 35 formed on the inner surface of the tip body 30 to which the tip 40 is fastened. The tip body 30 has a tapered portion 35a formed on the axial front end of the internal thread 35 to expand toward the opening.

[0197] A connection portion 39 connected to the gun body inner tube portion 21 is provided on the rear end side of the contact tip body 30 so as to cover the outer peripheral surface of the inner tube exposed portion 21 a .

[0198] The inner surface of the rear end of the connection part 39 is formed with an internal thread part 34 for fastening and connecting with the external thread part 21b formed at the front end of the inner tube part 21 of the gun body. At this time, the connection part 39 at the rear end side of the contact tip body 30 covers the front half of the inner tube exposed part 21a. In other words, the connection part 39 covers the entire outer peripheral surface of the inner tube exposed part 21a that is closer to the axial front end side than the supply side opening part 23a and the recovery side opening part 24a.

[0199] A conical portion 39a whose diameter is expanded to match the inner tube exposed portion 21a is formed on the front inner surface of the connecting portion 39, and the conical portion 39a is in surface contact with the inclined portion 21c formed at the front end of the inner tube exposed portion 21a. Thus, the contact area between the contact tip body 30 and the inner tube portion 21 of the gun body can be made larger. Figure 5 as well as Figure 6 Better.

[0200] Next, based on Figure 6 as well as Figure 7 The forced energization mechanism provided in the contact tip body 30 and the contact tip 40 will be described.

[0201] The contact tip body 30 guides the welding wire W supplied from the rear torch barrel 20 side toward the contact tip 40 at the front.

[0202] The contact tip body 30 includes: a wire pressing portion 33 that eccentrically pushes the inserted welding wire W; an eccentric guide portion 31 that forms a cylindrical space (hereinafter referred to as a pressing space) for eccentrically positioning the welding wire W; and a base end guide portion 32 that forms a cylindrical space disposed at the rear side of the eccentric guide portion 31. Figure 6 Better.

[0203] A pressing space formed by an eccentric guide portion 31 is formed on the inner circumference of the contact tip body 30. The eccentric guide portion 31 is disposed at the front end half of the contact tip body 30 and has a wire pressing portion 33 disposed in the middle of the axial direction. The pressing space in the eccentric guide portion 31 has a pre-designed first inner diameter R1.

[0204] The welding wire pressing part 33 includes: a spherical pressing member 36, which presses the welding wire W inserted into the eccentric guide part 31; a force member 37, which forces the pressing member 36 toward the radial outside; a holding part 38, which is provided on the conductive tip body 30 in a manner of holding the pressing member 36 and the force member 37; and a cover body 15, which covers the pressing member 36 and the force member 37 along the outer peripheral surface of the conductive tip body 30. This structure refers to Figure 6 Better.

[0205] The retaining portion 38 has: a groove portion 38A, which is recessed in the entire circumferential range on the outer surface of the eccentric guide portion 31; a pair of cut-off surfaces 38B, 38B, which are formed at 180° symmetrical positions relative to the cylindrical bottom surface of the groove portion 38A; and a through hole 38C, which penetrates the cut-off surface 38B on one side and the pressing space in the radial direction. The diameter of the through hole 38C is slightly larger than the width direction of the cut-off surface 38B. This structure refers to Figure 7 Better.

[0206] The pressing member 36 is a steel ball fitted into the through hole 38C and is held so as to be movable in the radial direction along the through hole 38C. The diameter of the pressing member 36 is larger than the first inner diameter R1 of the eccentric guide portion 31 and smaller than the outer diameter of the eccentric guide portion 31. Therefore, the steel ball as the pressing member 36 can be prevented from entering the eccentric guide portion 31.

[0207] The force-applying member 37 is a leaf spring formed in a C-shape along the groove portion 38A, and has a pair of clamping portions 37B and 37C that clamp a pair of cut surfaces 38B and 38B, and a connecting portion 37A that extends in an arc shape along the groove portion 38A and connects the pair of clamping portions 37B and 37C. It should be noted that, as a leaf spring formed in a C-shape, for example, a rod clamp can be cited. The clamping portion 37C on one side is bent inwardly in a manner that presses the spherical pressing member 36 in a direction in which it is pressed into the through hole 38C. The clamping portion 37B on the other side has a contact surface 37B1 that contacts the cut surface 38B over the entire width direction, and a locking portion 37B2 that is formed by bending the end of the clamping portion 37B relative to the contact surface 37B1 in a manner along the groove portion 38A. This structure refers to Figure 7 Better.

[0208] The cover 15 is a cylindrical member integrally fixed to the throttle portion 14. The cover 15 is formed longer in the axial direction than the groove portion 38A, and is attached to a predetermined position of the contact tip body 30 through the throttle portion 14, so that the cover 15 is installed in a manner covering the entirety of the groove portion 38A.

[0209] By covering the outer peripheral side of the groove portion 38A in which the pressing member 36 and the urging member 37 are provided with the cover 15 , it is possible to reliably prevent the pressing member 36 from coming out of the through hole 38C during welding work.

[0210] That is, the cover body 15 has a function of improving the cooling performance of the contact tip body 30 and a function as a cover covering the pressing member 36 .

[0211] The proximal end guide portion 32 is constituted by a distal end portion of the catheter 13 inserted into the inner tube exposed portion 21 a disposed on the inner peripheral surface of the connecting portion 39 and tightly connected to the inner peripheral surface of the connecting portion 39 .

[0212] Furthermore, the inner diameter of the catheter 13 defines the third inner diameter of the base end guide portion 32. Figure 6 As shown, the third inner diameter R3 is smaller in diameter than the first inner diameter R1.

[0213] (Conductive nozzle 40)

[0214] The conductive 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 front end. A front end opening 42a for releasing the welding wire W is formed at the front end of the conductive tip 40. The conductive tip 40 is formed of a metal material having electrical conductivity such as copper, and supplies welding current to the welding wire W.

[0215] 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 front end side of the contact tip body 30 .

[0216] The external thread portion 45 of the contact tip 40 has an inclined portion 45a formed axially forward of the external thread portion 45 to abut against the tapered portion 35a formed axially forward of the internal thread portion 35 of the contact tip body 30. This can increase the contact area between the contact tip 40 and the contact tip body 30.

[0217] The inner surface of the conductive nozzle 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, which is formed axially from a rear end opening portion 42b connected to the front end of the tapered portion 43 to a front end opening portion 42a and guides the welding wire W.

[0218] The guide hole 42 is formed along the central axis of the conductive tip 40 and has a front guide length T, which is the axial length from the front 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.

[0219] The front end guide length T and the second inner diameter R2 are set so that the welding wire W eccentric from the central axis of the conductive tip body 30 and the conductive tip 40 under the action of the welding wire pressing portion 33 can contact the rear end opening 42b and the front end opening 42a located at the front and rear ends of the guide hole 42. Figure 6 Specifically, the second inner diameter is preferably set to 1.05 to 1.35 times the wire diameter of the welding wire W.

[0220] The tapered portion 43 is formed so that its diameter gradually decreases from the rear end toward the front end. In the example shown in the figure, the rear end of the tapered portion 43 is connected to the front end side of the connecting portion 44 whose diameter is larger than the first inner diameter R1, and the front end of the tapered portion 43 is connected to the rear end opening portion 42b of the guide hole 42 having the second inner diameter R2.

[0221] The tapered portion 43 and the connecting portion 44 are structures that prevent the welding wire W bent by the welding wire pressing portion 33 from contacting the conductive tip body 30 and the conductive tip 40 side during the period from the pressing position of the welding wire W by the pressing member 36 to the rear end opening portion 42b of the guide hole 42, and are not limited to the above-mentioned shapes.

[0222] According to the conductive tip body 30 and the conductive tip 40 having the above-mentioned forced energization mechanism, the welding wire W supplied from the welding torch gun body 20 is eccentrically contacted with the conductive tip body 30 and the conductive tip 40 side at the third contact position X3 located at the front end position of the base end guide portion 32 (conduit 13) having the third inner diameter R3, the first contact position X1 pressed by the pressing member 36 in the eccentric guide portion 31 having the first inner diameter R1, the second contact position X2 near the rear end opening portion 42b of the guide hole 42, and the front end contact position X0 near the front end opening portion 42a of the guide hole 42.

[0223] At this time, in the axial direction of the contact tip body 30 and the contact tip 40 , the first bending section L1 is defined between the third contact position X3 and the first contact position X1 , and the second bending section L2 is defined between the first contact position X1 and the second contact position X2 .

[0224] That is, the welding wire W can be forcibly brought into contact with the vicinity of the front end position of the contact tip 40 with a predetermined contact force, regardless of whether the welding wire W has a tendency to bend. In other words, power can be forcibly supplied to the welding wire W. Thus, even when the front end opening 42a of the contact tip 40 is enlarged due to welding work, power supply to the welding wire W can be maintained, and thus the life of the contact tip 40 can be extended.

[0225] In addition, the wire pressing portion 33 adopts a spherical pressing member 36, so that the eccentric pressing member 36 of the welding wire W is in point contact with the fed welding wire W and slides while rotating, thereby reducing the friction in the feeding direction, thereby preventing the supply resistance of the welding wire W from increasing more than necessary.

[0226] (Nozzle mounting mechanism 50)

[0227] The nozzle mounting mechanism 50 includes a nut member 51 slidably provided along the axial direction of the gun body outer tube portion 22 , and an outer tube body 52 interposed between the nut member 51 and the nozzle 16 .

[0228] The nut member 51 is a cap nut inserted through the gun barrel outer tube portion 22 and is slidably provided along the gun barrel outer tube portion 22. Thus, the nut member 51 functions as a mounting body for mounting the outer tube body 52 provided with the nozzle 16 on the gun barrel outer tube portion 22.

[0229] The nut member 51 has a bottomed cylindrical shape with an open front. The bottom 51b of the nut member 51 is formed with an insertion hole 51c for the gun body outer tube portion 22 to be inserted. The inner surface front side of the nut member 51 is formed with an internal thread portion 51a that is fastened and connected to the outer tube body 52.

[0230] The nut member 51 is restricted from moving toward the axial front end side by the restriction member 53 and the positioning member 54 .

[0231] The positioning member 54 is composed of an annular member fitted into an annular groove formed on the outer surface side of the front end of the gun body outer tube portion 22. The restricting member 53 is an annular member made of resin, and is restricted by the positioning member 54 from moving toward the front end in the axial direction.

[0232] The nut member 51 is restricted from contacting the torch body 20 by the restriction member 53 and the bottom 51b, and is restricted from moving toward the axial front end at a predetermined position on the front end side of the torch body outer tube 22. Figure 5 as well as Figure 6 Better.

[0233] 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 body outer cylinder 22 and the outer diameter of the contact tip body 30. Thus, on the inner peripheral surface of the outer cylinder 52, there is formed an inner part 55 that covers at least the connecting part 39, the front and rear ends are separated by a sealing part 60 described later, and is connected to the supply side opening 23a and the recovery side opening 24a.

[0234] The cooling water supplied from the supply side opening 23a is supplied to the interior part 55, and the supplied cooling water is discharged from the recovery side opening 24a. In addition, the front and rear ends of the interior part 55 are sealed by the sealing part 60. Figure 5 as well as Figure 6 Better.

[0235] The outer cylinder 52 has an external thread 52a formed on the front end outer surface as a means for supporting the nozzle 16 to which the rear end of the nozzle 16 is fastened. The outer cylinder 52 has an external thread 52b formed on the rear end outer surface to which the internal thread 51a formed on the nut member 51 is fastened.

[0236] According to the nozzle mounting mechanism 50 of this structure, the nut member 51 is restricted from sliding forward by the restriction member 53 , while the rear portion of the outer cylinder 52 is fastened to the front portion of the nut member 51 , so that the nut member 51 is restricted from sliding backward by the restriction member 53 .

[0237] That is, the nozzle mounting mechanism 50 can fix the axial position of the outer cylinder 52 and the nut member 51 in the torch barrel 20. Therefore, the nozzle 16 fastened to the outer cylinder 52 can be provided to extend toward the axial front end side of the torch barrel 20.

[0238] In the above example, the nozzle 16 is detachably mounted on the outer cylinder 52, but the outer cylinder 52 and the nozzle 16 may be integrally formed. In this case, the nozzle 16 is directly detachably mounted on the nut member 51.

[0239] In addition, the limiting member 53 may be a structure capable of positioning the nut member 51 and the outer cylinder body 52 at a predetermined position on the front end side of the gun body outer cylinder portion 22, and is not limited to the above-mentioned structure. For example, the limiting member 53 may not be separated from the gun body outer cylinder portion 22, but a step portion for positioning the nut member 51 may be integrally formed on the outer surface of the gun body outer cylinder portion 22.

[0240] (Nozzle 16)

[0241] The nozzle 16 has a mechanism for spraying a shielding gas such as argon or carbon dioxide gas supplied from a gas supply device (not shown) toward the base material A to be welded.

[0242] The nozzle 16 is formed in a cylindrical shape capable of housing the contact tip body 30 , the throttle portion 14 , and the contact tip 40 which are integrally assembled.

[0243] The inner circumferential surface of the rear part of the nozzle 16 is formed with an internal threaded portion 16a to which the external threaded portion 52a of the outer cylinder 52 is fastened. The internal threaded portion 16a of the nozzle 16 extends to a position near the center of the outer cylinder 52 in the front-to-back direction, or to a position behind the center in the front-to-back direction. In other words, the rear side of the internal threaded portion 16a of the nozzle 16 in the front-to-back direction extends to the vicinity of the supply side opening 23a and the recovery side opening 24a in a side view. This structure refers to Figure 5 as well as Figure 6 Better.

[0244] That is, the contact area between the nozzle 16 and the outer cylinder 52 can be expanded as much as possible.

[0245] (Sealing portion 60)

[0246] 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.

[0247] The first seal portion 60A is formed by attaching an O-ring as a waterproof member to a first sleeve 61. Similarly, the second seal portion 60B is formed by attaching waterproof members 65 and 66 to a second sleeve 62.

[0248] The first sleeve 61 and the second sleeve 62 are cylindrical insulators formed of an insulating material such as synthetic resin, and have an insulating function of preventing electricity passing through the torch barrel 20 from flowing to the nozzle 16 via the outer cylindrical body 52 .

[0249] The waterproof members 63 , 64 , 65 , and 66 are O-rings formed of synthetic resin, rubber, or the like, and have a function of preventing the cooling water supplied to the interior portion 55 inside the outer cylinder 52 from leaking out of the outer cylinder 52 .

[0250] The first sleeve 61 is a tubular body having a cylindrical shape, and is disposed on the front end side of the inner portion 55 .

[0251] The first sleeve 61 has a locking portion 61 a at the rear end thereof, which is an annular protrusion that protrudes radially inward so as to be locked with a step portion formed at the front portion of the connection portion 39 .

[0252] An annular waterproof member 63 is provided in an annular groove formed on the outer peripheral surface of the first sleeve 61. The waterproof member 63 is in close contact with the inner peripheral surface of the outer cylinder 52. That is, the waterproof member 63 is provided so as to be sandwiched in the radial direction by the first sleeve 61 formed of an insulating member and the outer cylinder 52.

[0253] An annular waterproof member 64 is provided in an annular groove formed on the outer circumferential surface of the front portion of the connection portion 39 of the contact tip body 30 abutting against the inner circumferential surface of the first sleeve 61. The waterproof member 64 is provided to be sandwiched between the first sleeve 61 and the connection portion 39 of the contact tip body 30 in the radial direction.

[0254] According to the above, the first sleeve 61 and the waterproof member 63 form a first sealing portion 60A that seals the inner peripheral surface of the front end side of the outer cylinder 52 and the outer peripheral surface of the front side of the connecting portion 39 of the contact tip body 30. Figure 5 as well as Figure 6 Better.

[0255] It should be noted that the first sleeve 61 is installed and fixed in a state where the outer circumferential surface is inserted into the front end side of the outer cylinder body 52, and the inner circumferential surface of the first sleeve 61 is tightly attached to the connecting portion 39 of the conductive nozzle body 30 by fastening the conductive nozzle body 30 to the external threaded portion 21b of the inner cylinder exposed portion 21a.

[0256] The second sleeve 62 is a tubular body having a cylindrical shape, and is disposed on the rear end side of the inner portion 55 .

[0257] 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 cylinder 52 .

[0258] An annular waterproof member 65 is provided in an annular groove formed on the outer peripheral surface of the front portion of the second sleeve 62. The waterproof member 65 is provided so as to be sandwiched between the outer peripheral surface of the second sleeve 62 and the inner peripheral surface of the outer cylinder 52 in the radial direction.

[0259] An annular waterproof member 66 is provided in an annular groove formed on the inner circumference of the front portion of the second sleeve 62. The waterproof member 66 is provided so as to be sandwiched between the inner circumference of the second sleeve 62 and the outer circumference of the gun body outer tube portion 22 in the radial direction.

[0260] According to the above, the second sleeve 62 and the waterproof members 65 and 66 form a second sealing portion 60B that seals the inner circumference of the rear end of the outer cylinder 52 and the outer circumference of the front part of the gun body outer cylinder 22. Figure 5 as well as Figure 6 Better.

[0261] It should be noted that the second sleeve 62 is installed and fixed in a state where the outer circumference is inserted into the rear end side of the outer cylinder 52, and the flange portion 62a is locked to the rear end of the outer cylinder 52. In addition, by fastening the outer cylinder 52 to the nut member 51, the inner circumference of the second sleeve 62 is in close contact with the outer circumference of the gun body outer cylinder portion 22.

[0262] (Function and Effect)

[0263] The above-mentioned welding torch 10 is cooled by a supply process of supplying cooling water supplied from the cooling water supply part 12 to the supply path 23 to the internal part 55, a cooling process of directly water-cooling the connection part 39 of the conductive tip body 30 using the cooling water supplied by the internal part 55 and cooling the entire conductive tip body 30 through the connection part 39 or water-cooling the nozzle 16 through the outer cylinder 52, and a discharge process of discharging the cooling water that has been circulated in the internal part 55 and cooled by water from the recovery path 24.

[0264] The cooling water supplied to the internal part 55 contacts the outer surface of the connection part 39 and can be directly water-cooled, so the cooling efficiency of the entire contact tip body 30 that reaches a high temperature during arc welding is improved compared with the related art.

[0265] In addition, since the cooling efficiency is improved by the connection portion 39 extending the rear end of the contact tip body 30 backward, a special structure such as a forced energization mechanism can be provided in conjunction with the contact tip body 30 itself.

[0266] In addition, the rear side of the nozzle 16 is mounted on the outer cylinder 52 in a manner that covers the outer peripheral surface of the front half of the outer cylinder 52. In other words, the nozzle 16 is arranged in a manner that covers the supply side opening 23a and the recovery side opening 24a from the vicinity to the front end of the inner part 55 by means of the external threaded portion 52a at the front of the outer cylinder 52. Therefore, the cooling water supplied to the inner part 55 can efficiently cool the rear part of the nozzle 16 via the front part of the outer cylinder 52 with high thermal conductivity. This structure refers to Figure 5 According to the above, the cooling efficiency of the welding torch 10 is improved with a simple and low-cost structure.

[0267] Next, based on Figure 8 Other examples of the contact tip body 30 will be described with respect to points different from the above-described embodiment. Figure 8 2 is a cross-sectional view showing a contact tip body 30 according to another embodiment.

[0268] The contact tip body 30 has a body front portion 30A and a body rear portion 30B.

[0269] The main body front portion 30A is formed with an internal thread portion 35 to which the contact tip is fastened at the axial front end side, a holding portion 38 constituting the wire pressing portion 33, and an internal thread portion 72 to which the main body rear portion 30B is fastened at the axial base end side.

[0270] The main body rear portion 30B is formed with the external thread portion 71 to which the internal thread portion 72 of the main body front portion 30A is fastened at the axial front end side and the connection portion 39 to which the external thread portion 21b of the inner tube exposed portion 21a is fastened at the axial base end side.

[0271] According to the contact tip body 30 having this structure, only the body front portion 30A can be replaced while the body rear portion 30B is fastened to the inner cylinder exposed portion 21 a.

[0272] That is, the contact tip body 30 can replace only the body front portion 30A without removing the first sleeve 61 which is difficult to attach and detach because it is provided to seal the outer peripheral surface of the connecting portion 39 and the inner peripheral surface of the outer cylinder 52, thereby improving maintainability.

[0273] It should be noted that the present invention is not limited to the above-mentioned embodiments, and the combination of the various structures of the embodiments and the changes and applications made by those skilled in the art based on the description in the specification and known technologies are also intended by the present invention and included in the scope of protection requested.

[0274] As described above, the following matters are disclosed in this specification.

[0275] (1) A welding torch for gas shielded arc welding, wherein:

[0276] The welding torch has:

[0277] A welding torch body having a contact tip body mounted on the front end side thereof; and

[0278] The outer cylinder is mounted on the side of the welding torch body in a manner of being externally mounted on the welding torch body.

[0279] The welding torch body has an outer barrel and an inner barrel inserted into the outer barrel.

[0280] A supply path for supplying cooling water between the gun body inner tube and the gun body outer tube and a recovery path for recovering cooling water between the gun body outer tube are formed on the outer peripheral surface of the gun body inner tube.

[0281] The gun body inner tube has an inner tube exposed portion extending toward the axial front end side from the gun body outer tube,

[0282] A supply side opening at the axial front end side of the supply path and a recovery side opening at the axial front end side of the recovery path are formed on the base end side of the outer peripheral surface of the inner tube exposed portion.

[0283] A connection portion is provided on the rear end side of the conductive tip body to connect the axial front end side of the inner tube exposed portion.

[0284] The connecting portion is formed so as to cover the outer peripheral side of the exposed portion of the inner tube.

[0285] The outer cylinder has an interior portion that houses at least the connection portion, the supply-side opening, and the recovery-side opening.

[0286] The inner part is provided with a sealing part for sealing the outer cylinder body and the conductive nozzle body and the outer cylinder body and the gun body outer cylinder.

[0287] According to this structure, a simple structure in which the conductive nozzle body is formed in a manner that covers the connecting portion on the axial front end side of the inner tube of the gun body can be used to cool the axial rear end side of the conductive nozzle body using cooling water. Therefore, the conductive nozzle body can be efficiently cooled using a simple and low-cost structure, and the versatility is also improved.

[0288] (2) The welding torch according to (1), wherein:

[0289] The sealing portion at least comprises an insulator and a waterproof member.

[0290] The waterproof member seals the outer circumferential surface of the insulator and the outer cylinder arranged radially outside the insulator, or the inner circumferential surface of the insulator and the contact tip body or the gun body outer cylinder arranged radially inside the insulator.

[0291] According to this configuration, since the insulators are arranged at the front and rear sealing portions, insulation can be performed more reliably.

[0292] (3) The welding torch according to (1) or (2), wherein:

[0293] The welding torch has a cylindrical mounting body which is inserted through the welding torch body and whose axial movement toward the front end side is restricted by a restricting portion provided on the welding torch body.

[0294] The outer cylindrical body is fastened to the mounting body at a position closer to the axial front end side than the restricting portion, and thus the outer cylindrical body is restricted from moving in the axial direction in a state of being externally mounted on the contact tip body and the torch barrel.

[0295] According to this configuration, the outer cylinder can be fixed to a predetermined mounting position by being fastened to the mounting body, so that the assembly work is easy.

[0296] (4) The welding torch according to any one of (1) to (3), wherein:

[0297] The contact tip body comprises: an eccentric guide portion having a first inner diameter; and a welding wire pressing portion which makes the welding wire inserted into the eccentric guide portion eccentric in the radial direction.

[0298] The conductive tip connected to the axial front end side of the conductive tip body is provided with a guide hole formed along the axial direction from the front end opening formed at the front end to the rear end opening and guiding the welding wire.

[0299] The guide hole has a second inner diameter that is smaller than the first inner diameter.

[0300] According to this configuration, by arranging a wire pressing portion on the conductive tip body that utilizes the reaction force of the bending rigidity of the welding wire to stably contact the welding wire with the conductive tip, the entire welding torch can be compactly constructed, and the structure of the conductive tip that is replaced relatively frequently can be simplified, thereby keeping costs low.

[0301] (5) The welding torch according to (4), wherein:

[0302] A base end guide portion is provided on the base end side of the eccentric guide portion, and the base end guide portion has a third inner diameter.

[0303] The third inner diameter is smaller in diameter than the first inner diameter, and larger in diameter than the second inner diameter.

[0304] 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 the welding wire contacting the contact tip side is more stable.

[0305] (6) The welding torch according to (4), wherein:

[0306] The welding wire pressing portion at least comprises a pressing member in contact with the welding wire and an elastic member for pressing the pressing member toward the welding wire.

[0307] The pressing member is a spherical member.

[0308] The elastic member is configured as a leaf spring-shaped member.

[0309] According to this configuration, the pressing member pressing the welding wire is formed into a spherical shape. Therefore, the wire pressing portion can eccentrically deviate the welding wire in the radial direction and prevent the force required to feed the welding wire from the opening of the contact tip from becoming larger than necessary.

[0310] (7) The welding torch according to any one of (1) to (6), wherein:

[0311] The contact tip body includes a body rear portion on which the connection portion is provided and a body front portion detachably mounted on the front end side of the body rear portion.

[0312] According to this configuration, the main body front portion on the front side of the contact tip main body can be replaced without removing the sealing portion, so that the maintainability is improved.

[0313] (8) The welding torch according to any one of (1) to (7), wherein:

[0314] A metallic throttling portion is provided on the conductive nozzle body.

[0315] According to this structure, since thermal conductivity is improved, cooling performance is improved.

[0316] (9) The welding torch according to (8), wherein:

[0317] The throttle portion includes a cylindrical cover extending toward the front end side in the axial direction and covering the outer peripheral surface of the contact tip body.

[0318] According to this configuration, the heat transfer cross-sectional area of ​​the throttle portion increases, thereby contributing to improvement in cooling efficiency.

[0319] (10) A method for cooling a welding torch used for gas shielded arc welding, wherein:

[0320] The welding torch has:

[0321] A welding torch body having a contact tip body mounted on the front end side thereof; and

[0322] The outer cylinder is mounted on the side of the welding torch body in a manner of being externally mounted on the welding torch body.

[0323] The welding torch body has an outer barrel and an inner barrel inserted into the outer barrel.

[0324] A supply path for supplying cooling water between the gun body inner tube and the gun body outer tube and a recovery path for recovering cooling water between the gun body outer tube are formed on the outer peripheral surface of the gun body inner tube.

[0325] The gun body inner tube has an inner tube exposed portion extending toward the axial front end side from the gun body outer tube,

[0326] A supply side opening at the axial front end side of the supply path and a recovery side opening at the axial front end side of the recovery path are formed on the base end side of the outer peripheral surface of the inner tube exposed portion.

[0327] A connection portion connected to the conductive tip body is provided on the axial front end side of the inner tube exposed portion.

[0328] The connecting portion is connected in such a manner that the contact tip body covers the outer peripheral side of the inner cylinder exposed portion.

[0329] The outer cylinder has an interior portion that houses at least the connection portion, the supply-side opening, and the recovery-side opening.

[0330] The inner part is provided with a sealing part for sealing the outer cylinder and the conductive nozzle body and the outer cylinder and the gun body outer cylinder.

[0331] The cooling method of the welding torch comprises:

[0332] a supplying step of supplying the cooling water supplied from the supply-side opening to the interior portion;

[0333] a cooling step of cooling the connection portion using the cooling water; and

[0334] The recovery step is to recover the cooling water having cooled the interior portion from the recovery-side opening.

[0335] According to this structure, a simple structure in which the conductive nozzle body is formed in a manner that covers the connecting portion on the axial front end side of the inner tube of the gun body can be used to cool the axial rear end side of the conductive nozzle body using cooling water. Therefore, the conductive nozzle body can be efficiently cooled using a simple and low-cost structure, and the versatility is also improved.

Claims

1. A welding torch for gas shielded arc welding, wherein: The welding torch has: A welding torch body having a contact tip body mounted on the front end side thereof; and The outer cylinder is mounted on the side of the welding torch body in a manner of being externally mounted on the welding torch body. The welding torch body has an outer barrel and an inner barrel inserted into the outer barrel. A supply path for supplying cooling water between the gun body inner tube and the gun body outer tube and a recovery path for recovering cooling water between the gun body outer tube are formed on the outer peripheral surface of the gun body inner tube. The gun body inner tube has an inner tube exposed portion extending toward the axial front end side from the gun body outer tube, A supply side opening at the axial front end side of the supply path and a recovery side opening at the axial front end side of the recovery path are formed on the base end side of the outer peripheral surface of the inner tube exposed portion. A connection portion is provided on the rear end side of the conductive tip body to connect the axial front end side of the inner tube exposed portion. The connecting portion is formed so as to cover the outer peripheral side of the exposed portion of the inner tube. The outer cylinder has an interior portion that houses at least the connection portion, the supply-side opening, and the recovery-side opening. The inner part is provided with a sealing part for sealing the outer cylinder body and the conductive nozzle body and the outer cylinder body and the gun body outer cylinder.

2. The welding torch according to claim 1, wherein: The sealing portion at least comprises an insulator and a waterproof member. The waterproof member seals the outer circumferential surface of the insulator and the outer cylinder arranged radially outside the insulator, or the inner circumferential surface of the insulator and the contact tip body or the gun body outer cylinder arranged radially inside the insulator.

3. The welding torch according to claim 1, wherein: The welding torch has a cylindrical mounting body which is inserted through the welding torch body and whose axial movement toward the front end side is restricted by a restricting portion provided on the welding torch body. The outer cylindrical body is fastened to the mounting body at a position closer to the axial front end side than the restricting portion, and thus the outer cylindrical body is restricted from moving in the axial direction in a state of being externally mounted on the contact tip body and the torch barrel.

4. The welding torch according to any one of claims 1 to 3, wherein: The contact tip body comprises: an eccentric guide portion having a first inner diameter; and a welding wire pressing portion which makes the welding wire inserted into the eccentric guide portion eccentric in the radial direction. The conductive tip connected to the axial front end side of the conductive tip body is provided with a guide hole formed along the axial direction from the front end opening formed at the front end to the rear end opening and guiding the welding wire. The guide hole has a second inner diameter that is smaller than the first inner diameter.

5. The welding torch according to claim 4, wherein: A base end guide portion is provided on the base end side of the eccentric guide portion, and the base end guide portion has a third inner diameter. The third inner diameter is smaller in diameter than the first inner diameter, and is larger in diameter than the second inner diameter.

6. The welding torch according to claim 4, wherein: The welding wire pressing portion at least comprises a pressing member in contact with the welding wire and an elastic member for pressing the pressing member toward the welding wire. The pressing member is a spherical member. The elastic member is configured as a leaf spring-shaped member.

7. The welding torch according to claim 1, wherein: The contact tip body includes a body rear portion on which the connection portion is provided and a body front portion detachably mounted on the front end side of the body rear portion.

8. The welding torch according to claim 1, wherein: A metallic throttling portion is provided on the conductive nozzle body.

9. The welding torch according to claim 8, wherein: The throttle portion includes a cylindrical cover extending toward the front end side in the axial direction and covering the outer peripheral surface of the contact tip body.

10. A method for cooling a welding torch used for gas shielded arc welding, wherein: The welding torch has: A welding torch body having a contact tip body mounted on the front end side thereof; and The outer cylinder is mounted on the side of the welding torch body in a manner of being externally mounted on the welding torch body. The welding torch body has an outer barrel and an inner barrel inserted into the outer barrel. A supply path for supplying cooling water between the gun body inner tube and the gun body outer tube and a recovery path for recovering cooling water between the gun body outer tube are formed on the outer peripheral surface of the gun body inner tube. The gun body inner tube has an inner tube exposed portion extending toward the axial front end side from the gun body outer tube, A supply side opening at the axial front end side of the supply path and a recovery side opening at the axial front end side of the recovery path are formed on the base end side of the outer peripheral surface of the inner tube exposed portion. A connection portion connected to the conductive tip body is provided on the axial front end side of the inner tube exposed portion. The connecting portion is connected in such a manner that the contact tip body covers the outer peripheral side of the inner cylinder exposed portion. The outer cylinder has an interior portion that houses at least the connection portion, the supply-side opening, and the recovery-side opening. The inner part is provided with a sealing part for sealing the outer cylinder and the conductive nozzle body and the outer cylinder and the gun body outer cylinder. The cooling method of the welding torch comprises: a supplying step of supplying the cooling water supplied from the supply-side opening to the interior portion; a cooling step of cooling the connection portion using the cooling water; and The recovery step is to recover the cooling water having cooled the interior portion from the recovery-side opening.

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