Welding shield tool and welding method

Abstract

To provide a welding shield tool and a welding method capable of guaranteeing a gas shield property with a simple structure.SOLUTION: On an outer peripheral side of a welding torch T, annular members 41, 42, 43 coaxial to the welding torch T are disposed overlapped. The respective annular members 41, 42, 43 have cylindrical parts 41a, 42a, 43a along the outer peripheral surface of the welding torch T and flange parts 41b, 42b, 43b. Between the plurality of cylindrical parts 41a, 42a, 43a, first gas passages 48, 49 extending in an axial direction are formed; annular second gas passages 45, 46 extending in a circumferential direction are formed among the plurality of flange parts 41b, 42b, 43b. The first gas passages 48, 49 and the second gas passages 45, 46 communicate with each other, and jet a shield gas G supplied for the second gas passages 45, 46 from outside to the tip end side of the welding torch T via the first gas passages 48, 49.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a shielding jig and a welding method used for gas shielded welding.

Background Art

[0002] Gas shielded arc welding is known in which a shielding gas (inert gas) is supplied to a welding part to shield the welding part from air and prevent oxidation. A shielding jig used for such gas shielded arc welding is described in, for example, Patent Document 1. The shielding jig of Patent Document 1 arranges a double annular member on the outer peripheral side of a welding torch, forms an annular space between the double annular members, and arranges an annular hollow pipe above the annular space. A plurality of injection ports arranged in the circumferential direction of the annular space are formed in the hollow pipe, and shielding gas is introduced into the hollow pipe to reach the entire circumference of the annular space and is injected from each injection port toward the tip side of the welding torch.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the shielding jig of Patent Document 1 uses an annular hollow pipe, it is necessary to form a plurality of injection ports in the hollow pipe and arrange the hollow pipe between the double annular members, and the structure is complicated.

[0005] The present invention provides a welding shielding jig and a welding method that can ensure gas shielding performance with a simple structure during gas shielded welding (including laser welding).

Means for Solving the Problems

[0006] As a means for solving the above problems, in a first aspect of the present invention, a plurality of annular members coaxial with the welding torch are arranged in a stacked manner on the outer peripheral side of the welding torch. Each of the annular members has a cylindrical portion along the outer peripheral surface of the welding torch and a flange portion provided at an end of the cylindrical portion on the side opposite to the torch tip in the axial direction. The plurality of cylindrical portions overlap with each other with a first gap in the radial direction, and the plurality of flange portions overlap with each other with a second gap in the axial direction. A first gas flow path extending in the axial direction is formed in the first gap. An annular second gas flow path extending in the circumferential direction is formed in the second gap. The first gas flow path and the second gas flow path communicate with each other, and a welding shield jig is provided that injects shield gas supplied from the outside into the second gas flow path to the tip side of the welding torch through the first gas flow path. According to this configuration, a plurality of annular members having flange portions are stacked to form a jig body, and a first gas flow path extending in the axial direction and a second gas flow path extending in the circumferential direction are formed between the overlapping annular members. The second gas flow path allows the shield gas supplied from the outside to reach the entire circumference in the circumferential direction. The shield gas that has flowed through the entire circumference in the circumferential direction in the second gas flow path reaches the first gas flow path and flows toward the tip side of the torch, and is injected to the tip side of the welding torch. By forming a gas flow path that allows the shield gas to reach the entire circumference in the circumferential direction between the flange portions of the plurality of stacked annular members, a uniform and good shielding effect can be obtained over a wide range with a simple structure.

[0007] In a second aspect of the present invention, in the first aspect, the annular member includes a partition portion that partitions between the first gas flow path and the second gas flow path, and a communication portion that extends from the second gas flow path side to the first gas flow path side and through which the shield gas flows is formed in the partition portion. According to this configuration, the first gas flow path and the second gas flow path are partitioned by a partition portion, and after narrowing the flow path by a communication portion such as a groove or a hole formed in the partition portion, the shield gas is caused to flow from the second gas flow path to the first gas flow path. Thereby, the shield gas can be surely caused to reach the entire circumference in the circumferential direction by the second gas flow path, and the shield gas can be evenly injected in the circumferential direction.

[0008] The third aspect of the present invention is that, in the above first or second aspect, a plurality of the annular members are detachably coupled to each other by a fastening member. According to this configuration, since the plurality of annular members are detachably coupled, the maintainability can be improved, for example, by easily cleaning the attached fumes and spatter by disassembling the plurality of annular members.

[0009] The fourth aspect of the present invention is that, in any one of the above first to third aspects, it includes three or more of the annular members that overlap each other, and between a pair of the annular members adjacent to each other, the first gap and the first gas flow path, and the second gap and the second gas flow path are respectively formed. According to this configuration, by stacking three or more annular members and forming the first gas flow path and the second gas flow path between the respective annular members, the shielding gas is supplied by being divided into a plurality of layers of flow paths. Therefore, the injection range (shield area) of the shielding gas can be expanded.

[0010] The fifth aspect of the present invention provides a welding method using the welding shield jig according to any one of the above first to fourth aspects. According to this configuration, welding can be performed to obtain a uniform and good shielding effect by using a shield jig having a simple structure that utilizes the gaps between a plurality of annular members.

Effects of the Invention

[0011] According to the present invention, it is possible to provide a welding shield jig and a welding method that can ensure gas shielding properties with a simple structure.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Referring to FIGS. 1 to 3, the shielding jig 1 and the welding method of the embodiment are used, for example, in a gas shielded arc welding apparatus. The shielding jig 1 and the welding method of the embodiment will be described by taking the case of performing gas shielded arc welding as an example, but the present invention is not limited thereto.

[0014] <Welding apparatus> The gas shielded arc welding apparatus includes a welding torch T for shielded welding that melts and solidifies a metal filler M to form a weld bead. The welding torch T holds the filler M continuously supplied from the filler supply unit in a state of protruding from the tip of the torch. The welding torch T has a shielding nozzle S that receives a shielding gas G supplied from a shielding gas supply unit (not shown). The shielding gas G (inert gas) is supplied from the tip of the shielding nozzle S toward the welding part. The shielding nozzle S has a cylindrical shape with a straight central axis CL. Hereinafter, the direction along the axis CL of the shielding nozzle S is referred to as the axial direction, the direction orthogonal to the axis CL is referred to as the radial direction, and the circumferential direction around the center of the axis is referred to as the circumferential direction. Also, the tip side of the torch in the axial direction is referred to as the lower side, and the side opposite to the tip of the torch (base end side) is referred to as the upper side.

[0015] As the arc welding method, either a consumable electrode type such as covered arc welding or carbon dioxide arc welding, or a non-consumable electrode type such as TIG welding or plasma arc welding may be used. For the shielding gas G, for example, argon, helium, or a mixed gas thereof is used in MIG welding, carbon dioxide gas or a mixed gas of argon and carbon dioxide gas is used in MAG welding, and argon gas is used in TIG welding. Also, in laser welding, nitrogen, argon, or helium is used as the shielding gas G.

[0016] The heat source for melting the filler M is not limited to the arc described above. For example, other heat source methods such as a heating method that combines an arc and a laser, a heating method that uses plasma, a heating method that uses an electron beam or a laser, etc. may be adopted. When heating with an electron beam or a laser, the heating amount can be controlled more finely, and the state of the weld bead can be maintained more appropriately.

[0017] The filler material M is a welding wire for welding titanium and titanium alloys, which is made of, for example, pure titanium or a titanium alloy (see, for example, JIS Z 3331). If the filler material M is pure titanium or a titanium alloy, appropriate welding can be performed even when the base material to be welded is a titanium-based material.

[0018] The welding torch T generates an arc from the tip of the filler material M in a shielding gas atmosphere while holding the filler material M. The filler material M is fed to the welding torch T by a feeding mechanism (not shown). While the welding torch T moves, a weld bead, which is a molten and solidified body of the filler material M, is formed by melting and solidifying the continuously fed filler material M. At this time, the shielding gas G supplied from the shielding gas supply unit is jetted from the welding torch T to the welded portion to shield the filler material M.

[0019] <Shielding jig 1> A shielding jig 1 is attached to the outer periphery of the shielding nozzle S of the welding torch T so as to surround the outer periphery of the shielding nozzle S. The shielding jig 1 is detachably fixed to the shielding nozzle S using a fixing bolt B2 described later. The shielding jig 1 is supplied with the shielding gas G from the shielding gas supply unit and jets the shielding gas G toward the welded portion. The shielding gas supply unit supplies the shielding gas G to both the welding torch T and the shielding jig 1. The shielding jig 1 jets the shielding gas G on the outer peripheral side of the shielding nozzle S.

[0020] A gas supply pipe N1 is installed in the shielding jig 1. The downstream end of the gas supply pipe N1 penetrates the upper surface of the flange portion 11b and is inserted into the jig interior and connected to the annular upper gas flow path 15. The gas supply pipe N1 is provided singly in FIGS. 1 to 3 and supplies the shielding gas G in order from the upper gas flow path 15 on the upstream side to the lower gas flow path 17 on the downstream side among the plurality of layers of gas flow paths 15 to 17 in the shielding jig 1.

[0021] The gas supply configuration of the shielding jig 1 may be, for example, as shown in FIG. 11, in which a plurality of gas supply pipes N1 are provided for each layer of the gas flow paths 15 to 17, and the shielding gas G is individually supplied to each of the gas flow paths 15 to 17. In FIG. 11, it includes a gas supply pipe N1 connected to the upper gas flow path 15 and a gas supply pipe N2 connected to the middle gas flow path 16. Also, the gas type and flow rate may be changed for each layer.

[0022] The openings 18a and 19a that serve as the ejection ports of the shielding gas G in the shielding jig 1 have an annular shape that is continuous in the circumferential direction. The shielding gas G ejected downward from the openings 18a and 19a forms a cylindrical gas flow (hereinafter also referred to as a gas curtain). Note that the openings 18a and 19a are not limited to those having an annular shape formed along the circumferential direction. For example, the openings 18a and 19a may have a plurality of opening shapes divided in the circumferential direction.

[0023] From the openings 18a and 19a of the shielding jig 1, the shielding gas G is ejected annularly toward the welding part (the tip side of the welding torch T) to form a gas curtain. Inside the inner circumference of the gas curtain, the shielding gas G is ejected from the shielding nozzle S of the welding torch T. Inside the inner circumference of the gas curtain, the shielding gas G ejected from the shielding nozzle S is confined and the inflow of external air is blocked. Thereby, the retention of the shielding gas G ejected from the welding torch T is promoted, the gas shielding effect at the welding part is enhanced, and the welding bead during welding is effectively isolated from the external air. According to the shielding jig 1 of the embodiment, a good gas shielding effect can be obtained with a small amount of gas by the gas curtain of the shielding gas G and the shielding gas G supplied into the gas curtain.

[0024] Hereinafter, the structure of the shielding jig 1 will be described in detail. Referring to FIGS. 4 and 5, the shielding jig 1 is composed of a plurality of annular members 11 to 14 coaxially stacked with the welding torch T. Hereinafter, each of the annular members 11 to 14 will be referred to as the first annular member 11, the second annular member 12, the third annular member 13, and the fourth annular member 14 in order from the top in the exploded perspective views of FIGS. 4 and 5.

[0025] Each of the first, third, and fourth annular members 11, 13, and 14 includes a cylindrical portion 11a, 13a, 14a along the outer peripheral surface of the welding torch T, and a disc-shaped flange portion 11b, 13b, 14b formed with an enlarged diameter at the end portion of the cylindrical portion 11a, 13a, 14a on the opposite side of the torch tip in the axial direction. The second annular member 12 is formed by a flange portion 12b sandwiched between the flange portions 11b, 13b of the first and third annular members 11, 13 and does not have a cylindrical portion.

[0026] Hereinafter, the cylindrical portion 11a and the flange portion 11b of the first annular member 11 will be referred to as the first cylindrical portion 11a and the first flange portion 11b, respectively, the flange portion 12b of the second annular member 12 will be referred to as the second flange portion 12b, the cylindrical portion 13a and the flange portion 13b of the third annular member 13 will be referred to as the third cylindrical portion 13a and the third flange portion 13b, respectively, and the cylindrical portion 14a and the flange portion 14b of the fourth annular member 14 will be referred to as the fourth cylindrical portion 14a and the fourth flange portion 14b, respectively.

[0027] The material of each of the annular members 11 to 14 is not particularly limited, but metals and non-ferrous metals are preferred. Each of the annular members 11 to 14 is, for example, integrally formed. The inner diameter of the first cylindrical portion 11a may be manufactured according to the outer diameter of the welding torch T, or an adapter adapted to the outer diameter of the welding torch T may be used.

[0028] Referring to FIGS. 3 and 9 together, the first, third, and fourth cylindrical portions 11a, 13a, 14a have diameters that increase in the order of the first, third, and fourth cylindrical portions 11a, 13a, 14a. The first, third, and fourth cylindrical portions 11a, 13a, 14a overlap with each other, leaving first gaps S21, S22 in the radial direction from the inner peripheral side to the outer peripheral side. Hereinafter, the gap S21 between the first and third cylindrical portions 11a, 13a is referred to as the inner peripheral side gap, and the gap S22 between the third and fourth cylindrical portions 13a, 14a is referred to as the outer peripheral side gap.

[0029] The inner peripheral side gap S21 forms a cylindrical inner peripheral gas flow path 18 (first gas flow path) extending in the axial direction. The lower end opening 18a of the inner peripheral gas flow path 18 (the opening at the lower end height of the first cylindrical portion 11a) constitutes an annular inner peripheral gas injection port 18a. The outer peripheral side gap S22 forms a cylindrical outer peripheral gas flow path 19 (first gas flow path) extending in the axial direction. The lower end opening 19a of the outer peripheral gas flow path 19 (the opening at the lower end height of the third cylindrical portion 13a) constitutes an annular outer peripheral gas injection port 19a. The above-described first gas flow path is not limited to a cylindrical integrated flow path that is continuous in the circumferential direction, and may be a plurality of flow paths divided in the circumferential direction by ribs or the like.

[0030] The lower end of the fourth cylindrical portion 14a is at the lower end height of the shield jig 1. The lower end of the third cylindrical portion 13a (and the outer peripheral gas injection port 19a) is located above the lower end of the fourth cylindrical portion 14a. The lower end of the first cylindrical portion 11a (and the inner peripheral gas injection port 18a) is located above the lower end of the third cylindrical portion 13a. As a result, at the lower end of the shield jig 1, the shielding gas G is injected from the gas injection ports 18a, 19a at different heights.

[0031] The height of each gas injection port 18a, 19a (the length of each cylindrical portion 11a, 13a, 14a) may be changed as appropriate. FIG. 10 shows an example in which the lower end heights of the respective cylindrical portions 11a, 13a, 14a are made the same. In this case, at the lower end of the shield jig 1, the shielding gas G is injected from the gas injection ports 18a, 19a at the same height. The gaps S21 and S22 between the respective cylindrical portions 11a, 13a, and 14a are not particularly limited, but are preferably 1 to 8 mm, more preferably 1 to 6 mm, and even more preferably 1 to 4 mm.

[0032] Referring to FIGS. 3 and 9, the first to fourth flange portions 11b to 14b overlap with each other with second gaps S11, S12, and S13 in the axial direction between those adjacent in the axial direction. Hereinafter, the gap S11 between the first and second flange portions 11b and 12b is referred to as the upper gap S11, the gap S12 between the second and third flange portions 12b and 13b is referred to as the middle gap S12, and the gap S13 between the third and fourth flange portions 13b and 14b is referred to as the lower gap S13.

[0033] The upper gap S11 forms an annular upper gas flow path 15 extending in the circumferential direction. The downstream side of the gas supply pipe N1 communicates with the upper gas flow path 15, and the shielding gas G is supplied from the gas supply pipe N1. The middle gap S12 forms an annular middle gas flow path 16 (second gas flow path) extending in the circumferential direction. The upper gas flow path 15 communicates with the middle gas flow path 16 through a first communication hole 12h described later, and the shielding gas G is supplied from the upper gas flow path 15. The lower gap S13 forms an annular lower gas flow path 17 (second gas flow path) extending in the circumferential direction. The middle gas flow path 16 communicates with the lower gas flow path 17 through a second communication hole 13h described later, and the shielding gas G is supplied from the middle gas flow path 16.

[0034] Referring to FIGS. 3 and 6, a plurality (a pair in the figure) of first communication holes 12h (through holes) for communicating the upper gas flow path 15 and the middle gas flow path 16 are formed in the second flange portion 12b. The opening area of the first communication hole 12h is smaller than the flow path cross-sectional area of the upper gas flow path 15. Therefore, the shielding gas G supplied to the upper gas flow path 15 is supplied to the middle gas flow path 16 from each first communication hole 12h in a state of covering the entire circumference of the upper gas flow path 15.

[0035] Referring to FIGS. 3 and 7, a plurality (a pair in the figure) of second communication holes 13h (through holes) for communicating the middle-stage gas flow path 16 and the lower-stage gas flow path 17 are formed in the third flange portion 13b. The second through holes 13h are arranged at positions avoiding the first through holes 12h in the circumferential direction (positions not overlapping with the first through holes 12h). The opening area of the second through holes 13h is smaller than the flow path area of the middle-stage gas flow path 16. Therefore, the shielding gas G supplied to the middle-stage gas flow path 16 is supplied to the lower-stage gas flow path 17 from each second communication hole 13h in a state of covering the entire circumference of the middle-stage gas flow path 16.

[0036] The inner circumferential side end portion of the middle-stage gas flow path 16 is located on the outer circumferential side of the upper end portion of the inner circumferential gas flow path 18. Above the third cylindrical portion 13a of the third annular member 13, an annular first upper end wall 13d (partition portion) protruding upward is formed. The first upper end wall 13d partitions between the inner circumferential side end portion of the middle-stage gas flow path 16 and the upper end portion of the inner circumferential gas flow path 18. A plurality of first communication grooves 13g opening upward are formed at equal intervals in the circumferential direction in the first upper end wall 13d. Each first communication groove 13g extends radially, for example, along the radial direction. Each first communication groove 13g forms a flow path for flowing the shielding gas G extending from the middle-stage gas flow path 16 side (outer circumferential side) to the inner circumferential gas flow path 18 side (inner circumferential side).

[0037] The shielding gas G supplied to the middle-stage gas flow path 16 flows to the inner circumferential side through each first communication groove 13g, collides with the first cylindrical portion 11a, then flows downward through the inner circumferential gas flow path 18, and is jetted from the lower end opening 18a of the inner circumferential gas flow path 18 to the welding portion.

[0038] Each first communication groove 13g extends radially, for example, along the radial direction, but may extend inclined with respect to the radial direction like the first communication groove 13g' shown in FIG. 12. The shielding gas G passing through each first communication groove 13g' inclined with respect to the radial direction becomes a spiral flow (swirling flow) centered on the axis CL in the inner peripheral gas flow path 18 and flows downward, and is jetted downward from the opening 18a. Thereby, the shielding gas G jetted from the opening 18a forms a gas curtain having a spiral flow. Since a rotational flow is added to the shielding gas G in this gas curtain having a spiral flow, the inflow of air into the welded portion is more reliably prevented, and the gas shielding effect of the welded portion is further enhanced.

[0039] Referring to FIGS. 3 and 8, the inner peripheral side end portion of the lower gas flow path 17 is located on the outer peripheral side of the upper end portion of the outer peripheral gas flow path 19. Above the fourth cylindrical portion 14a in the fourth annular member 14, an annular second upper end wall 14d (partition portion) protruding upward is formed. The second upper end wall 14d partitions between the inner peripheral side end portion of the lower gas flow path 17 and the upper end portion of the outer peripheral gas flow path 19. A plurality of second communication grooves 14g opening upward are formed at equal intervals in the circumferential direction in the second upper end wall 14d. Each second communication groove 14g extends radially, for example, along the radial direction. Each second communication groove 14g forms a flow path that extends from the lower gas flow path 17 side (outer peripheral side) to the outer peripheral gas flow path 19 side (inner peripheral side) and through which the shielding gas G flows.

[0040] The shielding gas G supplied to the lower gas flow path 17 flows to the inner peripheral side through each second communication groove 14g, collides with the third cylindrical portion 13a, then flows downward through the outer peripheral gas flow path 19, and is jetted from the lower end opening 18a of the outer peripheral gas flow path 19 to the welded portion. Similar to the first communication groove 13g', each second communication groove 14g may also extend inclined with respect to the radial direction.

[0041] The upper gap S11 (upper gas flow path 15) is formed by a first annular groove 15a formed on the lower surface of the first flange portion 11b. The middle gap S12 (middle gas flow path 16) is formed by a second annular groove 16a formed on the lower surface of the second flange portion 12b and a third annular groove 16b formed on the upper surface of the third flange portion 13b. The second annular groove 16a is wider in the radial direction than the first annular groove 15a and the third annular groove 16b, and is formed so as to extend to the inner peripheral side of the first annular groove 15a. The third annular groove 16b is formed offset to the inner peripheral side of the second annular groove 16a.

[0042] The lower gap S13 (lower gas flow path 17) is formed by a fourth annular groove 17a formed on the upper surface of the fourth flange portion 14b. The fourth annular groove 17a is formed at a radial position equivalent to that of the first annular groove 15a. The flow path cross-sectional area of the lower gas flow path 17 formed by the fourth annular groove 17a is smaller than the flow path cross-sectional area of the middle gas flow path 16 formed by the second and third annular grooves 16a, 16b. Part of the shielding gas G supplied to the middle gas flow path 16 is supplied to the inner peripheral gas flow path 18, and the remainder is supplied to the lower gas flow path 17.

[0043] Seal grooves for accommodating packings 15p, 15p2 (O-rings) are formed on the outer peripheral side and the inner peripheral side of the upper surface of the second flange portion 12b, respectively. Seal grooves for accommodating packings 16p, 17p (O-rings) are formed on the outer peripheral side of the upper surfaces of the third flange portion 13b and the fourth flange portion 14b, respectively.

[0044] An annular fixed upper end wall 11d protruding upward is formed above the first cylindrical portion 11a of the first annular member 11. A plurality of nut holes extending in the radial direction are formed through the fixed upper end wall 11d at equal intervals in the circumferential direction. Fixing bolts B2 are screwed into the respective nut holes from the outer side in the radial direction. By tightening these fixing bolts B2 and pressing the bolt tips against the outer peripheral surface of the shield nozzle S, the shield jig 1 is fixed to the outer periphery of the shield nozzle S.

[0045] In the first to fourth flange portions 11b to 14b, a plurality of bolt insertion holes and nut holes that are coaxially continuous along the axial direction are formed at equal intervals in the circumferential direction. A fastening bolt B1 is inserted into each bolt insertion hole from above. Each fastening bolt B1 is screwed into and tightened in a nut hole formed in the fourth flange portion 14b. Thereby, the first to fourth flange portions 11b to 14b are integrally fastened, and thus the first to fourth annular members 11 to 14 are integrated to form the shield jig 1.

[0046] The shield jig 1 can be removed from the shield nozzle S and can be divided into a plurality of annular members 11 to 14 by loosening the fastening by each fastening bolt B1. Therefore, even if fumes and spatter adhere, it can be easily cleaned and can be used permanently. In the embodiment, a plurality of annular members 11 to 14 are joined using the fastening bolts B1 and O-rings, but gaskets, Teflon (registered trademark), etc. may be used instead of the O-rings, and the annular members may be joined by brazing instead of the fastening bolts B1.

[0047] As described above, in the shield jig 1 in the above embodiment, a plurality of annular members 11, 13, 14 coaxial with the welding torch T are arranged in a stacked manner on the outer peripheral side of the welding torch T. Each of the annular members 11, 13, 14 has a cylindrical portion 11a, 13a, 14a along the outer peripheral surface of the welding torch T, and flange portions 11b, 13b, 14b provided at the ends of the cylindrical portions 11a, 13a, 14a on the opposite side of the torch tip in the axial direction. The plurality of cylindrical portions 11a, 13a, 14a overlap with each other with first gaps S21, S22 in the radial direction. The plurality of flange portions 11b, 13b, 14b overlap with each other with second gaps S12, S13 in the axial direction. First gas flow paths 18, 19 extending in the axial direction are formed in the first gaps S21, S22. Annular second gas flow paths 16, 17 extending in the circumferential direction are formed in the second gaps S12, S13. The first gas flow paths 18, 19 and the second gas flow paths 16, 17 communicate with each other, and the shielding gas G supplied from the outside to the second gas flow paths 16, 17 is jetted to the tip side of the welding torch T through the first gas flow paths 18, 19.

[0048] According to this configuration, a plurality of annular members 11, 13, 14 having flange portions 11b, 13b, 14b are stacked to form a jig body, and between the annular members 11, 13, 14 that overlap each other, a first gas flow path 18, 19 extending in the axial direction and a second gas flow path 16, 17 extending in the circumferential direction are formed. The second gas flow paths 16, 17 allow the shield gas G supplied from the outside to reach the entire circumference in the circumferential direction. The shield gas G that has flowed through the entire circumference in the circumferential direction within the second gas flow paths 16, 17 reaches the first gas flow paths 18, 19 and flows toward the tip side of the torch, and is jetted to the tip side of the welding torch T. By forming a gas flow path that allows the shield gas G to reach the entire circumference in the circumferential direction between the flange portions 11b, 13b, 14b of the plurality of stacked annular members 11, 13, 14, a uniform and good shielding effect can be obtained over a wide range while having a simple structure.

[0049] In the above shield jig 1, the annular members 13, 14 are provided with partition portions (upper end walls 13d, 14d) that partition between the first gas flow paths 18, 19 and the second gas flow paths 16, 17, and communication grooves 13g, 14g that extend from the second gas flow path 16, 17 side to the first gas flow path 18, 19 side and through which the shield gas G flows are formed in the partition portions. According to this configuration, the first gas flow paths 18, 19 and the second gas flow paths 16, 17 are partitioned by the partition portions, and after narrowing the flow path by the communication grooves 13g, 14g formed in the partition portions, the shield gas G is caused to flow from the second gas flow paths 16, 17 to the first gas flow paths 18, 19. Thereby, the shield gas G can be surely caused to reach the entire circumference in the circumferential direction by the second gas flow paths 16, 17, and the shield gas G can be jetted evenly in the circumferential direction. The configuration is not limited to forming a groove in the partition portion to allow the shield gas G to flow, and a configuration in which a hole is formed in the partition portion to allow the shield gas G to flow may also be used.

[0050] In the above shield jig 1, the plurality of annular members 11, 13, 14 are detachably coupled to each other by a fastening member B1. According to this configuration, by detachably coupling a plurality of annular members 11, 13, and 14, maintainability can be improved, such as easily cleaning the attached fumes and spatter by disassembling the plurality of annular members 11, 13, and 14. That is, in a configuration using a mesh to rectify the shielding gas G as in the prior art, when fumes and spatter adhered, clogging occurred and it was necessary to frequently replace the mesh. In the configuration of the present embodiment, even if fumes and spatter adhere to the annular members 11, 13, and 14, they can be easily cleaned, and the jig components can be used permanently.

[0051] In the shielding jig 1, three annular members 11, 13, and 14 that overlap each other are provided, and first gaps S21, S22 and first gas flow paths 18, 19, and second gaps S12, S13 and second gas flow paths 16, 17 are respectively formed between a pair of adjacent annular members 11, 13, and 14. According to this configuration, by stacking three or more annular members 11, 13, and 14 and forming first gas flow paths 18, 19 and second gas flow paths 16, 17 between the respective annular members 11, 13, and 14, the shielding gas G is supplied by being divided into a plurality of layers of flow paths. Therefore, the injection range (shielding area) of the shielding gas G can be widened. By increasing the annular members 11, 13, and 14 on the outer peripheral side, a shielding effect can be obtained in a wider range.

[0052] And according to the welding method using the shielding jig 1, welding with a uniform and good shielding effect can be performed using the shielding jig 1 having a simple structure that utilizes the gaps between the plurality of annular members 11, 13, and 14.

[0053] <Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. 13 to 18. The shield jig 31 of this embodiment is particularly different from the shield jig 1 of the first embodiment in that it includes plate-shaped gaskets 45p and 46p instead of O-rings, and an annular water-cooling jig 57 is attached to the outer peripheral side of the outermost cylindrical portion 43a. For other configurations identical to those of the above embodiments, the same reference numerals are used and detailed descriptions are omitted.

[0054] Referring to FIGS. 13 to 16, the shield jig 31 is configured by stacking a plurality of annular members 41, 42, and 43 coaxial with the welding torch T. Hereinafter, each of the annular members 41, 42, and 43 will be referred to as a first annular member 41, a second annular member 42, and a third annular member 43 in order from the top in the exploded perspective view of FIG. 15.

[0055] Each of the first to third annular members 41 to 43 includes a cylindrical portion 41a, 42a, 43a along the outer peripheral surface of the welding torch T, and a disk-shaped flange portion 41b, 42b, 43b formed with an enlarged diameter at an end portion in the axial direction of the cylindrical portions 41a, 42a, 43a on the side opposite to the torch tip.

[0056] Hereinafter, the cylindrical portion 41a and the flange portion 41b of the first annular member 41 will be referred to as a first cylindrical portion 41a and a first flange portion 41b, respectively, the cylindrical portion 42a and the flange portion 42b of the second annular member 42 will be referred to as a second cylindrical portion 42a and a second flange portion 42b, respectively, and the cylindrical portion 43a and the flange portion 43b of the third annular member 43 will be referred to as a third cylindrical portion 43a and a third flange portion 43b, respectively.

[0057] The material of each of the annular members 41 to 43 is not particularly limited, but metals and non-ferrous metals are preferred. Each of the annular members 41 to 43 is, for example, integrally formed. The inner diameter of the first cylindrical portion 41a may be manufactured in accordance with the outer diameter of the welding torch T, or an adapter adjusted to the outer diameter of the welding torch T may be used.

[0058] The first to third cylindrical portions 41a to 43a have diameters that increase in the order of the first to third cylindrical portions 41a to 43a. The first to third cylindrical portions 41a to 43a overlap with each other with first gaps S21 and S22 in the radial direction from the inner peripheral side to the outer peripheral side. Hereinafter, the gap S21 between the first and second cylindrical portions 41a and 42a is referred to as the inner peripheral side gap, and the gap S22 between the second and third cylindrical portions 42a and 43a is referred to as the outer peripheral side gap.

[0059] The inner peripheral side gap S21 forms a cylindrical inner peripheral gas flow path 48 (first gas flow path) extending in the axial direction. The lower end opening 48a of the inner peripheral gas flow path 48 (the opening at the lower end height of the first cylindrical portion 41a) constitutes an annular inner peripheral gas injection port 48a. The outer peripheral side gap S22 forms a cylindrical outer peripheral gas flow path 49 (first gas flow path) extending in the axial direction. The lower end opening 49a of the outer peripheral gas flow path 49 (the opening at the lower end height of the third cylindrical portion 43a) constitutes an annular outer peripheral gas injection port 49a. The above-described first gas flow path is not limited to a cylindrical integral flow path continuous in the circumferential direction, and may be a plurality of flow paths divided in the circumferential direction by ribs or the like.

[0060] The lower end of the third cylindrical portion 43a is at the lower end height of the shield jig 31. The lower end of the second cylindrical portion 42a (and the outer peripheral gas injection port 49a) is located above the lower end of the third cylindrical portion 43a. The lower end of the first cylindrical portion 41a (and the inner peripheral gas injection port 48a) is located above the lower end of the second cylindrical portion 42a. As a result, at the lower end of the shield jig 31, the shield gas G is injected from the gas injection ports 48a and 49a at different heights. The heights of the respective gas injection ports 48a and 49a (the lengths of the respective cylindrical portions 41a and 42a) may be appropriately changed (see FIG. 10).

[0061] The first to third flange portions 41b to 43b overlap with each other with second gaps S11 and S12 in the axial direction between those adjacent to each other in the axial direction. Hereinafter, the gap S11 between the first and second flange portions 41b and 42b is referred to as the upper stage gap, and the gap S12 between the second and third flange portions 42b and 43b is referred to as the lower stage gap. The upper gap S11 forms an annular upper gas flow path 45 (second gas flow path) extending in the circumferential direction. The downstream side of the first gas supply pipe N1 communicates with the upper gas flow path 45, and shielding gas G is supplied from the first gas supply pipe N1.

[0062] The lower gap S12 forms an annular lower gas flow path 46 (second gas flow path) extending in the circumferential direction. The downstream side of the second gas supply pipe N2 communicates with the lower gas flow path 46 via the collar member C1, and shielding gas G is supplied from the second gas supply pipe N2. That is, in the second embodiment, shielding gas G is supplied individually to the plurality of gas flow paths 45, 46. Note that a configuration in which shielding gas G is supplied in order from the upstream gas flow path 45 to the downstream gas flow path 46 as in the first embodiment may also be used.

[0063] The upper gas flow path 45 is partitioned in the axial direction into a first upper flow path and a second upper flow path by the first gasket 45p crossing the upper and lower intermediate portions. A plurality (for example, a pair) of first communication holes 45h (through holes) for communicating the first upper flow path and the second upper flow path are formed in the first gasket 45p. The lower gas flow path 46 is partitioned in the axial direction into a first lower flow path and a second lower flow path by the second gasket 46 crossing the upper and lower intermediate portions. A plurality (for example, a pair) of second communication holes 46h (through holes) for communicating the first lower flow path and the second lower flow path are formed in the second gasket 46.

[0064] Referring also to FIG. 17, the inner peripheral side end of the second upper flow path of the upper gas flow path 45 is located on the outer peripheral side of the upper end of the inner peripheral gas flow path 48. Above the second cylindrical portion 42a of the second annular member 42, an annular first upper end wall 42d (partition portion) protruding upward is formed. The first upper end wall 42d partitions between the inner peripheral side end of the second upper flow path of the upper gas flow path 45 and the upper end of the inner peripheral gas flow path 48. A plurality of first communication grooves 42g opening upward are formed at equal intervals in the circumferential direction in the first upper end wall 42d (see the first communication groove 13g in FIG. 7). Each first communication groove 42g forms a flow path for flowing shielding gas G extending from the upper gas flow path 45 side (outer peripheral side) to the inner peripheral gas flow path 48 side (inner peripheral side).

[0065] The shielding gas G supplied to the upper gas flow path 45 flows inward through each first communication groove 42g, flows downward through the inner peripheral gas flow path 48 after colliding with the first cylindrical portion 41a, and is jetted from the lower end opening 48a of the inner peripheral gas flow path 48 to the welding portion. Each first communication groove 42g extends radially along, for example, the radial direction, but may extend obliquely with respect to the radial direction (see the first communication groove 13g' in FIG. 12).

[0066] Referring also to FIG. 18, the inner peripheral side end of the second lower flow path of the lower gas flow path 46 is located on the outer peripheral side of the upper end portion of the outer peripheral gas flow path 49. Above the third cylindrical portion 43a in the third annular member 43, an annular second upper end wall 43d (partition portion) protruding upward is formed. The second upper end wall 43d partitions between the inner peripheral side end of the second lower flow path of the lower gas flow path 46 and the upper end portion of the outer peripheral gas flow path 49. A plurality of second communication grooves 43g that open upward are formed at equal intervals in the circumferential direction in the second upper end wall 43d (see the second communication groove 14g in FIG. 8). Each second communication groove 43g forms a flow path for the shielding gas G to flow from the lower gas flow path 46 side (outer peripheral side) to the outer peripheral gas flow path 49 side (inner peripheral side).

[0067] The shielding gas G supplied to the lower gas flow path 46 flows inward through each second communication groove 43g, flows downward through the outer peripheral gas flow path 49 after colliding with the second cylindrical portion 42a, and is jetted from the lower end opening 49a of the outer peripheral gas flow path 49 to the welding portion. Each second communication groove 43g extends radially along, for example, the radial direction, but may extend obliquely with respect to the radial direction (see the first communication groove 13g' in FIG. 12).

[0068] The upper gap S11 (upper gas flow path 45) is formed by a first annular groove 45a formed on the lower surface of the first flange portion 41b and a second annular groove 45b formed on the upper surface of the second flange portion 42b. The lower gap (upper gas flow path 45) is formed by a third annular groove 46a formed on the lower surface of the second flange portion 42b and a fourth annular groove 46b formed on the upper surface of the third flange portion 43b. Each annular groove has, for example, the same radial width and the same radial position, but at least one of these may be different.

[0069] Above the first cylindrical portion 41a of the first annular member 41, an annular fixed upper end wall 41d protruding upward is formed. In the fixed upper end wall 41d, nut holes extending along the radial direction are formed through at a plurality of locations equidistant in the circumferential direction. A fixing bolt B2 is screwed into each nut hole from the outside in the radial direction. By tightening each of these fixing bolts B2 and pressing the tip of the bolt against the outer peripheral surface of the shield nozzle S, the shield jig 31 is fixed to the outer periphery of the shield nozzle S.

[0070] In the first to third flange portions 41b to 43b, a plurality of bolt insertion holes and nut holes coaxially connected along the axial direction are formed at equal intervals in the circumferential direction. A fastening bolt B1 is inserted into each bolt hole from above. Each fastening bolt B1 is screwed into and tightened in the nut hole formed in the third flange portion 43b. Thereby, the first to third flange portions 43b are integrally fastened, and thus the first to third annular members 41 to 43 are integrated to form the shield jig 31.

[0071] The shield jig 31 can be removed from the shield nozzle S and disassembled by loosening the fastening by each fastening bolt B1, and thus can be easily cleaned even if fumes or spatter adhere, and can be used permanently.

[0072] An annular water-cooling jig 57 is attached to the outer peripheral side of the third cylindrical portion 43a. The water-cooling jig 57 has an annular shape that continues below the third flange portion 43b, and has an upper surface that contacts the lower surface of the third flange portion 43b and an inner peripheral surface that contacts the outer peripheral surface of the third cylindrical portion 43a. In a cross-section along the axial direction, the water-cooling jig 57 surrounds the corner between the third cylindrical portion 43a and the third flange portion 43b in the third annular member 43 from the outer peripheral side and the lower side, forming a water channel 59 with a rectangular cross-section. Seal grooves for accommodating packing 58p1, 58p2 (O-rings) are formed on the upper surface and the inner peripheral surface of the water-cooling jig 57, respectively. A water supply and drainage pipe N5 connected to the water channel 59 is installed on the outer peripheral portion of the water-cooling jig 57.

[0073] By cooling the tip side of the welding torch T with the water-cooling jig 57 to stabilize the temperature, the welding torch T can be protected and stable welding can be performed. The fixing structure of the water-cooling jig 57 is formed, for example, with bolt insertion holes for inserting fastening bolts B3 from below on the outer peripheral side of the water-cooling jig 57. Each fastening bolt B3 is screwed into a nut hole formed in the third flange portion 43b and tightened. Thereby, the water-cooling jig 57 is integrally fastened to the third flange portion 43b and thus to the jig body.

[0074] As described above, in the shielding jig 31 in the above embodiment, a plurality of annular members 41, 42, 43 coaxial with the welding torch T are arranged on the outer peripheral side of the welding torch T. Each annular member 41, 42, 43 has a cylindrical portion 41a, 42a, 43a along the outer peripheral surface of the welding torch T and a flange portion 41b, 42b, 43b provided at an end portion of the cylindrical portion 41a, 42a, 43a on the opposite side of the torch tip in the axial direction. The plurality of cylindrical portions 41a, 42a, 43a overlap with each other with first gaps S21, S22 in the radial direction, and the plurality of flange portions 41b, 42b, 43b overlap with each other with second gaps S11, S12 in the axial direction. First gas flow paths 48, 49 extending in the axial direction are formed in the first gaps S21, S22, and annular second gas flow paths 45, 46 extending in the circumferential direction are formed in the second gaps S11, S12. The first gas flow paths 48, 49 and the second gas flow paths 45, 46 communicate with each other, and the shielding gas G supplied from the outside to the second gas flow paths 45, 46 is jetted to the tip side of the welding torch T through the first gas flow paths 48, 49. According to this configuration, a plurality of annular members 41, 42, 43 having flange portions 41b, 42b, 43b are stacked to form the jig body, and a first gas flow path 48, 49 extending in the axial direction and a second gas flow path 45, 46 extending in the circumferential direction are formed between the overlapping annular members 41, 42, 43. The second gas flow paths 45, 46 allow the shielding gas G supplied from the outside to reach the entire circumference in the circumferential direction. The shielding gas G that has flowed through the entire circumference in the circumferential direction in the second gas flow paths 45, 46 reaches the first gas flow paths 48, 49 and flows toward the torch tip side, and is jetted to the tip side of the welding torch T. By forming a gas flow path that allows the shielding gas G to reach the entire circumference in the circumferential direction between the flange portions 41b, 42b, 43b of the plurality of stacked annular members 41, 42, 43, a uniform and good shielding effect can be obtained over a wide range with a simple structure.

[0075] In the shielding jig 31, the annular members 42, 43 are provided with partition portions (upper end walls 42d, 43d) that partition between the first gas flow paths 48, 49 and the second gas flow paths 45, 46, and communication grooves 42g, 43g that extend from the second gas flow path 45, 46 side to the first gas flow path 48, 49 side and through which the shielding gas G flows are formed in the partition portions. According to this configuration, the first gas flow paths 48 and 49 and the second gas flow paths 45 and 46 are partitioned by a partition portion, and after narrowing the flow paths by the communication grooves 42g and 43g formed in the partition portion, the shielding gas G is caused to flow from the second gas flow paths 45 and 46 to the first gas flow paths 48 and 49, so that the shielding gas G can surely reach the entire circumference in the circumferential direction by the second gas flow paths 45 and 46, and the shielding gas G can be evenly injected in the circumferential direction. The configuration is not limited to forming a groove in the partition portion to allow the shielding gas G to flow, and a configuration in which a hole is formed in the partition portion to allow the shielding gas G to flow may also be used.

[0076] In the above shielding jig 31, the plurality of annular members 41 to 43 are detachably coupled to each other by a fastening member B1. According to this configuration, since the plurality of annular members 41 to 43 are detachably coupled, the maintainability can be improved, such as easily cleaning the attached fumes and sputters by disassembling the plurality of annular members 41 to 43. That is, in the configuration using a mesh to rectify the shielding gas G as in the prior art, clogging occurs when fumes and sputters adhere, and it is necessary to frequently replace the mesh. In the configuration of the present embodiment, even if fumes and sputters adhere to the annular members 41 to 43, they can be easily cleaned, and the jig component parts can be used permanently.

[0077] In the above shielding jig 31, three or more annular members 41 to 43 that overlap each other are provided, and between a pair of adjacent annular members 41 to 43, first gaps S21 and S22, first gas flow paths 48 and 49, and second gaps S11 and S12, and second gas flow paths 45 and 46 are respectively formed. According to this configuration, by stacking three or more annular members 41 to 43 and forming the first gas flow paths 48 and 49 and the second gas flow paths 45 and 46 between the respective annular members 41 to 43, the shielding gas G is supplied by being divided into a plurality of layers of flow paths, so that the injection range (shielding area) of the shielding gas G can be widened. By increasing the annular members 41 to 43 on the outer peripheral side, a shielding effect can be obtained in a wider range.

[0078] According to the welding method using the shielding jig 31, welding with a uniform and good shielding effect can be performed by using the shielding jig 31 having a simple structure that utilizes the gaps between the plurality of annular members 41 to 43.

[0079] Note that the configuration in the above embodiment is an example of the present invention, and various modifications can be made without departing from the gist of the present invention, such as replacing the components of the embodiment with well-known components. FIG. 19 shows a modification of the shielding jig 31 of the second embodiment. As shown in FIG. 19, a throttle portion S1 that tapers so that the diameter decreases toward the tip may be formed at the tip of the shielding nozzle S. A gas rectifying portion R1 such as a mesh, a foamed metal, or a sintered alloy may be provided on the outlet side of the gas flow path. In the figure, the gas rectifying portions R1 are provided in the annular first gas flow paths 48 and 49 extending in the axial direction, respectively. The gas rectifying portion R1 is, for example, a disk-shaped member extending along the annular gas flow path. Gas rectifying portions R1 having different diameters may be provided in each of the plurality of gas flow paths, or the gas rectifying portion R1 may be provided only in any one of the gas flow paths. That is, the gas rectifying portion R1 may be provided in at least one of the plurality of gas flow paths. The throttle portion S1 and the gas rectifying portion R1 described above may be applied to the shielding jig 1 of the first embodiment.

Explanation of Reference Numerals

[0080] 1 Shielding jig 11 First annular member (annular member) 11a Cylindrical portion 11b Flange portion 13 Third annular member (annular member) 13a Cylindrical portion 13b Flange portion 13d Upper end wall 13g Communication groove 14 Fourth annular member (annular member) 14a Cylindrical portion 14b Flange portion 14d Upper end wall 14g Communication groove 16 Middle gas flow path (second gas flow path) 17 Lower gas flow path (second gas flow path) 18 Inner peripheral gas flow path (first gas flow path) 19 Outer peripheral gas flow path (first gas flow path) 31 Shielding jig 41 First annular member (annular member) 41a Cylindrical portion 41b Flange portion 42 Second annular member (annular member) 42a Cylindrical portion 42b Flange portion 42d Upper end wall 42g Communication groove 43 Third annular member (annular member) 43a Cylindrical portion 43b Flange portion 43d Upper end wall 43g Communication groove 45 Upper gas flow path (second gas flow path) 46 Lower gas flow path (second gas flow path) 48 Inner peripheral gas flow path (first gas flow path) 49 Outer peripheral gas flow path (first gas flow path) B1 Fastening bolt (fastening member) G Shielding gas S11, S12, S13 Second gap S21, S22 First gap T Welding torch

Claims

1. A plurality of annular members are arranged coaxially with the welding torch in a stacked manner on the outer periphery of the welding torch, Each of the annular members has a cylindrical portion that is aligned with an outer circumferential surface of the welding torch, and a flange portion that is provided at an end of the cylindrical portion opposite to the tip of the torch in the axial direction, The cylindrical portions overlap each other with a first gap therebetween in the radial direction, The flange portions overlap each other with a second gap therebetween in the axial direction, A first gas flow passage extending in an axial direction is formed in the first gap, a second gas flow passage having an annular shape and extending in a circumferential direction is formed in the second gap, The first gas flow passage and the second gas flow passage are connected to each other, and a shielding gas supplied from the outside to the second gas flow passage is sprayed toward the tip side of the welding torch via the first gas flow passage.

2. the annular member includes a partition portion that separates the first gas flow passage and the second gas flow passage, The welding shield jig according to claim 1 , wherein the partition portion is formed with a communication portion extending from the second gas flow passage side to the first gas flow passage side to allow the shield gas to flow.

3. The welding shield jig according to claim 1 or 2, wherein the plurality of annular members are removably connected to each other by a fastening member.

4. Three or more of the annular members overlapping each other, 3. The welding shield jig according to claim 1, wherein the first gap and the first gas flow passage, and the second gap and the second gas flow passage are formed between a pair of the annular members adjacent to each other, respectively.

5. A welding method using the welding shield jig according to claim 1 or 2.

Images