After-shield gas jig, welding device, welding equipment, welding method, and method for manufacturing cylindrical structure

Abstract

An after-shield gas jig (10) is provided with a gas supply unit (20). The gas supply unit (20) includes a discharging unit (21h). An after-shield gas can be blown out from the discharging unit (21h) toward a workpiece (200). The gas supply unit (20) includes a shielding unit (21) and a first maintenance mechanism unit (22). The shielding unit (21) is disposed so as to surround the discharging unit (21h) when viewed from the direction in which the after-shield gas is blown out. The distance between the shielding unit (21) and the workpiece (200) can be kept constant independently of the position of a welding torch (1) by the first maintenance mechanism unit (22).

Description

After-shield gas jig, welding device, welding equipment, welding method, and manufacturing method of cylindrical structure

[0001] The present disclosure relates to an after-shield gas jig, a welding device, a welding facility, a welding method, and a method for manufacturing a cylindrical structure.

[0002] Conventionally, welding equipment used to manufacture cylindrical structures and the like sometimes has a rotating roller that maintains a constant distance between the welding torch and the workpiece. The after-shield gas jig that supplies the after-shield gas also has a shielding portion. The shielding portion suppresses the diffusion of the after-shield gas to prevent oxidation of the weld bead (see, for example, JP 2022-149068 A).

[0003] See Japanese Patent Application Laid-Open No. 2022-149068

[0004] However, in the welding device described above, although the rotating rollers maintain a constant distance between the shielding part and the workpiece, the after-shield gas jig moves in conjunction with the welding torch, so the relative position of the shielding part with respect to the workpiece is not properly set, which may result in insufficient suppression of the diffusion of the after-shield gas.

[0005] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a welding device in which the diffusion of after-shield gas is suppressed.

[0006] An after-shield gas jig according to the present disclosure includes a gas supply unit. The gas supply unit has an exhaust unit. After-shield gas can be blown out from the exhaust unit toward the workpiece. The gas supply unit has a shielding unit and a first maintaining mechanism unit. When viewed from the direction in which the after-shield gas is blown out, the shielding unit is arranged to surround the exhaust unit. The first maintaining mechanism unit can maintain a constant distance between the shielding unit and the workpiece, independent of the position of the welding torch.

[0007] A welding device according to the present disclosure includes a welding torch and an after-shield gas jig. A welding facility according to the present disclosure includes a welding device, a holding mechanism, and a rotation mechanism. The holding mechanism holds a workpiece. The rotation mechanism rotates the workpiece.

[0008] A welding method according to the present disclosure includes the steps of moving a workpiece near a welding device and welding the workpiece. In the moving step, the workpiece is moved so as to come into contact with a first maintaining mechanism. In the welding step, a welding torch generates an arc toward the workpiece. In the welding step, after-shield gas is blown from a gas supply unit toward the workpiece. In the welding step, the first maintaining mechanism maintains a constant distance between the shielding unit and the workpiece. In the welding step, the second maintaining mechanism maintains a constant distance between the welding torch and the workpiece.

[0009] A welding method according to the present disclosure includes the steps of moving a workpiece near a welding device and welding the workpiece. In the moving step, the workpiece is moved so as to come into contact with a first maintaining mechanism. In the welding step, a welding torch generates an arc toward the workpiece. In the welding step, after-shield gas is blown toward the workpiece from a gas supply unit. In the welding step, the first maintaining mechanism maintains a constant distance between the shielding unit and the workpiece. In the welding step, the drive unit adjusts the distance between the welding torch and the workpiece.

[0010] A method for manufacturing a cylindrical structure according to the present disclosure is a method for manufacturing a cylindrical structure using the above welding method, in which the workpiece is a body portion and a pair of end portions that constitute the cylindrical structure.

[0011] According to the above, a welding device in which diffusion of after-shield gas is suppressed can be obtained.

[0012] FIG. 1 is a perspective view of a welding apparatus according to a first embodiment. FIG. 2 is a schematic cross-sectional view of a gas supply unit taken along line II-II in FIG. 1 . FIG. 3 is a schematic cross-sectional view of a welding apparatus according to a first embodiment. FIG. 4 is a schematic cross-sectional view showing a modified example of a gas supply unit in a welding apparatus according to a first embodiment. FIG. 5 is a schematic cross-sectional view showing a modified example of a gas supply unit in a welding apparatus according to a first embodiment. FIG. 6 is a schematic cross-sectional view showing a modified example of a gas supply unit in a welding apparatus according to a first embodiment. FIG. 7 is a schematic cross-sectional view showing a modified example of a gas supply unit in a welding apparatus according to a first embodiment. FIG. 8 is a side view showing a modified example of a side shielding unit in a welding apparatus according to a first embodiment. FIG. 9 is a side view showing a modified example of a side shielding unit in a welding apparatus according to a first embodiment. FIG. 10 is a side view showing a modified example of a side shielding unit in a welding apparatus according to a first embodiment. FIG. 11 is a front view showing a modified example of a first maintenance mechanism unit in a welding apparatus according to a first embodiment. FIG. 12 is a side view showing a modified example of a side shielding unit in a welding apparatus according to a first embodiment. Fig. 1 is a cross-sectional schematic diagram showing a modified example of an after-shield gas jig in the welding apparatus according to embodiment 1. Fig. 2 is a perspective view showing a modified example of an after-shield gas jig in the welding apparatus according to embodiment 1. Fig. 3 is a cross-sectional perspective view showing a gas supply unit in the welding apparatus according to embodiment 2. Fig. 4 is a cross-sectional perspective view showing a gas supply unit in the welding apparatus according to embodiment 3. Fig. 5 is a cross-sectional perspective view showing a modified example of the gas supply unit in the welding apparatus according to embodiment 3. Fig. 6 is a cross-sectional perspective view showing a gas supply unit in the welding apparatus according to embodiment 3. Fig. 7 is a perspective view of a welding apparatus according to embodiment 4. Fig. 8 is a schematic view for explaining the configuration of a modified example of the welding apparatus according to embodiment 4. Fig. 9 is a schematic view of welding equipment according to embodiment 5.

[0013] Hereinafter, embodiments of the present disclosure will be described. Unless otherwise specified, the same or corresponding parts in the following drawings will be denoted by the same reference numerals, and the description thereof will not be repeated.

[0014] Embodiment 1. <Configuration of Welding Apparatus> Fig. 1 is a perspective view of welding apparatus 100 according to embodiment 1. Fig. 2 is a cross-sectional schematic view of gas supply unit 20 taken along line II-II in Fig. 1. Fig. 3 is a cross-sectional schematic view of welding apparatus 100 according to embodiment 1.

[0015] 1 to 3 is a welding device 100 that performs the so-called TIG (Tungsten Inert Gas) welding method, and is part of a welding installation 300 (see FIG. 19 ) that will be described later. Welding device 100 mainly includes a welding torch 1, a drive unit 2, and an after-shielding gas jig 10. Welding torch 1 is held by drive unit 2 (not shown). The position of welding torch 1 can be adjusted by drive unit 2.

[0016] The welding torch 1 is maintained at a constant distance from the workpiece 200 (the molten pool of the workpiece). However, the after-shield gas jig 10, which moves in conjunction with the welding torch 1, supplies after-shield gas to the thermally deformed workpiece 200 after welding. Another method is to slowly lower the welding torch 1 before each welding operation to bring the electrode 1a of the welding torch 1 into contact with the workpiece 200, and then energize the welding torch 1 and the workpiece 200 to check the distance between the welding torch 1 and the workpiece 200 and maintain a constant relative position between the welding torch 1 and the workpiece 200. In this case, to avoid contact between the after-shield gas jig 10 and the workpiece 200, an additional distance must be provided between the after-shield gas jig 10 and the workpiece 200, equivalent to the distance the welding torch 1 descends.

[0017] 3, welding torch 1 has an electrode portion 1a. By supplying power to electrode portion 1a, an arc is generated between electrode portion 1a and workpiece 200. When welding workpiece 200, welding torch 1 is held by drive portion 2, so the absolute position of welding torch 1 does not need to change, and the distance between welding torch 1 and workpiece 200 may be adjusted based on the voltage of the arc.

[0018] The electrode portion 1a has a rod-like shape along a central axis 1c, as shown in Fig. 3. When the electrode portion 1a has a rod-like shape, the central axis 1c of the electrode portion 1a is a virtual axis that extends along the extension direction of the electrode portion 1a and passes through the center of the electrode portion 1a in a cross section perpendicular to the extension direction.

[0019] When the workpiece 200 is a cylindrical structure, the welding torch 1 may be positioned so that the central axis 1c is perpendicular to a tangent line of the cylindrical structure. The tangent line is a tangent line at the welded portion A. The welded portion A is the location where the cylindrical structure is welded by the welding torch 1.

[0020] The after-shield gas jig 10 includes a gas supply unit 20, a pair of rails 30, and a first connection unit 40. The first connection unit 40 is slidable on the rails 30. The first connection unit 40 can hold the welding torch 1. Specifically, the first connection unit 40 has a sliding unit 41, a first block unit 42, a second block unit 43, and an arm unit 44.

[0021] The sliding portion 41 is connected to the rail 30 and is capable of sliding on the rail 30. The first block portion 42 is connected to be fixed to the sliding portion 41. The second block portion 43 is connected to be fixed to the first block portion 42. The arm portion 44 is connected to be fixed to the second block portion 43. The arm portion 44 can hold the welding torch 1.

[0022] When the welding torch 1 is disposed so that the central axis 1c is perpendicular to the tangent line of the workpiece 200, the rail 30 extends in the same direction as the central axis 1c. In this case, when the first connection portion 40 slides on the rail 30, the arm portion 44 moves along the central axis 1c.

[0023] Each of the pair of rails 30 has a stopper 31. The stopper 31 is disposed at the upper end of the rail 30. In this manner, the sliding portion 41 does not come off the rail 30.

[0024] The gas supply unit 20 has an exhaust unit 21h, a shielding unit 21, and a filter 21f. The after-shield gas is blown out from the exhaust unit 21h toward the workpiece 200. The exhaust unit 21h is a space formed by being surrounded by the shielding unit 21. A filter 21f is disposed in the space (exhaust unit 21h).

[0025] The discharge portion 21h has a discharge surface 21s. As shown in FIG. 3, the discharge surface 21s faces the workpiece 200. The after-shield gas is blown out from the discharge surface 21s. The direction in which the after-shield gas is blown out is perpendicular to the discharge surface 21s. In FIG. 3, the direction in which the after-shield gas is blown out is defined as the Z direction. In FIG. 3, the X direction is defined as the direction in which the welding torch 1 is disposed as viewed from the discharge portion 21h. The X direction is defined as a direction perpendicular to the Z direction. The direction perpendicular to the X and Z directions is defined as the Y direction. Note that, as shown in FIG. 3, the Z direction is also a direction perpendicular to the tangent of the workpiece 200.

[0026] The shielding portion 21 includes a top shielding portion 21a, a rear shielding portion 21b, and a pair of side shielding portions 21c. In a cross-sectional view of the gas supply portion 20 seen from the Y direction, as shown in FIG. 2, the cross-sectional shape of the top shielding portion 21a is, for example, L-shaped. Specifically, the top shielding portion 21a has a convex portion 21g. The convex portion 21g is formed toward the workpiece 200. As shown in FIG. 3, the convex portion 21g of the top shielding portion 21a is located at a position closest to the welding torch 1 in the X direction.

[0027] 1, the pair of side surface shielding portions 21c are spaced apart from each other in the Y direction. The pair of side surface shielding portions 21c are arranged to sandwich the top surface shielding portion 21a.

[0028] 3, the rear shielding portion 21b is disposed at a position farthest from the welding torch 1 in the X direction. The rear shielding portion 21b is connected to the top shielding portion 21a and the pair of side shielding portions 21c. In this manner, the top shielding portion 21a, the rear shielding portion 21b, and the pair of side shielding portions 21c are connected to each other to form the discharge portion 21h. The top shielding portion 21a, the rear shielding portion 21b, and the pair of side shielding portions 21c may be connected to each other by any method, and may be fastened to each other by screws, for example.

[0029] In this way, the shielding portion 21 is disposed so as to surround the discharge portion 21h, thereby preventing the after-shield gas from leaking and diffusing from the gap between the discharge surface 21s and the workpiece 200. As a result, the after-shield gas can sufficiently shield the welded portion A of the workpiece 200 from the atmosphere. In particular, it is preferable that the discharge portion 21h be surrounded on all sides by the shielding portion 21.

[0030] The after-shield gas may be argon gas, nitrogen gas, helium gas, carbon dioxide gas, or a mixture of these gases, etc. The mixture may contain oxygen gas as an active gas.

[0031] A piping joint 51 is connected to the rear shielding part 21b. A through hole is formed on the side surface of the rear shielding part 21b, and the piping joint 51 is attached to the through hole. A cable (not shown) branching from centralized piping in a factory or the like is connected to the piping joint 51 arranged in this manner. The piping joint 51 communicates the cable with the exhaust part 21h. After-shield gas is supplied to the exhaust part 21h via the piping joint 51. The piping joint 51 may be connected to either the top shielding part 21a or the side shielding part 21c.

[0032] The after-shield gas supplied to the discharge portion 21h is blown out from the discharge surface 21s toward the workpiece 200 via the filter 21f. As shown in FIG. 2, in a side view of the gas supply portion 20, the filter 21f is disposed between the discharge surface 21s and the piping joint 51 in the Z direction. The filter 21f has, for example, a mesh shape. In this manner, the after-shield gas is rectified by passing through the filter 21f. In other words, the after-shield gas is prevented from being blown out locally toward the workpiece 200, and is blown out over a wide area toward the workpiece 200.

[0033] The filter 21f may be fixed in the discharge portion 21h by any method. For example, grooves may be formed in the protrusion 21g of the top shielding portion 21a, the rear shielding portion 21b, and the pair of side shielding portions 21c. The filter 21f is held in the discharge portion 21h by fitting the outer periphery of the filter 21f into the grooves.

[0034] The gas supply unit 20 may have a plurality of filters 21f. Specifically, the number of filters 21f may be one, or may be, for example, two as shown in FIG. 2, or may be three or more. The plurality of filters 21f may be arranged spaced apart from one another in the Z direction. By providing a plurality of filters 21f in this way, the after-shield gas is more rectified and is blown out over a wider range toward the workpiece 200.

[0035] The filter 21f may have any shape as long as it is mesh-like, and may be made of a material such as a metal mesh, punched metal, steel wool, or a combination of these, in addition to a metal mesh. The filter 21f may also be made of a porous ceramic or metal material.

[0036] Here, a feature of after-shield gas jig 10 according to the first embodiment is that gas supply unit 20 can adjust the distance between shielding unit 21 and workpiece 200 independently of the position of welding torch 1. Specifically, gas supply unit 20 has first maintenance mechanism unit 22 as a maintenance mechanism unit. First maintenance mechanism unit 22 has ball roller 22a and bracket 22b.

[0037] 1, the side surface of the bracket 22b may be, for example, L-shaped. Specifically, the bracket 22b has a first surface and a second surface. The first surface is perpendicular to the second surface.

[0038] Bracket 22b may be connected to gas supply unit 20, and in the present embodiment 1, a first surface of bracket 22b is connected to side surface shielding unit 21c. Bracket 22b may be fixed to side surface shielding unit 21c by any method, and may be connected via a screw, for example.

[0039] A ball roller 22a is connected to the bracket 22b. Specifically, the ball roller 22a is connected to, for example, a cylindrical part. A through hole may be formed in the second surface of the bracket 22b. A male thread may be formed on the side of the cylindrical part, and a female thread may be formed on the inner peripheral surface of the through hole. In other words, the cylindrical part may be inserted into the through hole of the bracket 22b, and the cylindrical part may be fixed to the bracket 22b so that the second surface is sandwiched by a nut. The ball roller 22a is arranged at the tip of the cylindrical part. The ball roller 22a is capable of rolling on the surface of the workpiece 200.

[0040] The first maintenance mechanism 22 may be connected to at least one of the pair of side surface shielding parts 21 c. Two first maintenance mechanisms 22 may be provided. In this case, the first maintenance mechanism 22 may be connected to each of the pair of side surface shielding parts 21 c.

[0041] As shown in FIG. 1 , the first maintaining mechanism 22 may be connected to one of the side shielding parts 21 c. Assume that the workpiece 200 is composed of two separate members. When welding and connecting two separate members, if one of the two separate members has an uneven surface or an inclined surface, it may be difficult to adjust the distance between the after-shield gas jig 10 and the workpiece 200 even if two first maintaining mechanisms 22 are brought into contact with the workpiece 200. In such a case, there is no need to provide two first maintaining mechanisms 22; the first maintaining mechanism 22 may be connected to one of the side shielding parts 21 c by the workpiece 200.

[0042] The operation of welding torch 1 and after-shielding gas jig 10 will now be described. The position of welding torch 1 is adjusted by drive unit 2. Welding torch 1 is held by drive unit 2. When welding torch 1 is moved upward (along central axis 1c) away from workpiece 200, sliding portion 41 comes into contact with stopper 31. Gas supply unit 20 is connected to rail 30. Therefore, after-shielding gas jig 10 moves upward together with welding torch 1.

[0043] When welding workpiece 200, welding torch 1 is positioned at a desired position by drive unit 2. At this time, ball roller 22a is in contact with workpiece 200. The position of welding torch 1 is fixed by drive unit 2. In other words, the absolute position of welding torch 1 is determined by drive unit 2, and the relative position of welding torch 1 with respect to workpiece 200 can change.

[0044] As will be described later, welding apparatus 100 may include processing circuitry 3 (see FIG. 18 ). Processing circuitry 3 detects the voltage of the arc generated from electrode portion 1 a of welding torch 1. Driving unit 2 may adjust the distance between welding torch 1 and workpiece 200 based on the detected arc voltage.

[0045] On the other hand, when the workpiece 200 is welded, the after-shield gas jig 10 is supported by the ball rollers 22a with respect to the workpiece 200. In other words, the relative position of the shielding part 21 with respect to the workpiece 200 is determined by the first maintaining mechanism part 22.

[0046] When the workpiece 200 is a cylindrical structure, the workpiece 200 may be eccentric or may have variations in roundness. In these cases, when the workpiece 200 rotates, the relative positions of the welding torch 1 and the shielding part 21 with respect to the workpiece 200 change.

[0047] If the relative position of the shielding portion 21 with respect to the workpiece 200 changes, there is a risk that the after-shield gas will diffuse from the gap between the shielding portion 21 and the workpiece 200. As a result, the welded portion A of the workpiece 200 will no longer be able to be sufficiently shielded from the atmosphere by the after-shield gas.

[0048] In the after-shield gas jig 10 according to the first embodiment, when the workpiece 200 is rotating, the ball rollers 22a roll on the surface of the workpiece 200. Therefore, even if the workpiece 200 is eccentric or the roundness of the workpiece 200 varies, the relative position of the shielding part 21 with respect to the workpiece 200 does not change. In other words, the first maintaining mechanism part 22 maintains the distance between the shielding part 21 and the workpiece 200 constant.

[0049] The rail 30 is connected to the gas supply unit 20. Therefore, the absolute position of the rail 30 changes as the absolute position of the gas supply unit 20 changes. Because the absolute position of the welding torch 1 is adjusted by the drive unit 2, the first connection unit 40 slides on the rail 30. In other words, the distance between the shielding unit 21 and the workpiece 200 is maintained constant, independent of the position of the welding torch 1. In this way, the relative position of the shielding unit 21 with respect to the workpiece 200 is appropriately set so that the diffusion of the after-shield gas from the gap between the discharge surface 21s and the workpiece 200 is further suppressed. As a result, the after-shield gas can be sufficiently shielded from the atmosphere at the welded portion A of the workpiece 200. This also suppresses oxidation of the welded portion A.

[0050] The welding torch 1 does not have to be held by the drive unit 2. For example, the welding torch 1 may be held by the first connection portion 40. The first connection portion 40 may be held by the drive unit 2.

[0051] Fig. 4 is a cross-sectional schematic diagram showing a modified example of gas supply unit 20 in welding apparatus 100 according to embodiment 1. Fig. 4 corresponds to Fig. 2. Welding apparatus 100 shown in Fig. 4 basically has the same configuration as welding apparatus 100 shown in Figs. 1 to 3, but differs in the structure of upper surface shielding portion 21a. Specifically, upper surface shielding portion 21a includes curved surface portion 21r. Curved surface portion 21r is formed on the inner circumferential surface of upper surface shielding portion 21a at a corner of convex portion 21g.

[0052] In this way, the after-shield gas supplied from the piping joint 51 does not accumulate in the corners of the exhaust portion 21h but flows downward.

[0053] Figures 5 to 7 are cross-sectional schematic views showing modified examples of gas supply unit 20 in welding apparatus 100 according to embodiment 1. Each of Figures 5 to 7 corresponds to Figure 2. Welding apparatus 100 shown in Figures 5 to 7 basically has the same configuration as welding apparatus 100 shown in Figures 1 to 3, but differs in that gas supply unit 20 includes diffusion plate 52.

[0054] The diffuser plate 52 is disposed within the discharge portion 21h. The diffuser plate 52 prevents the after-shield gas supplied from the piping joint 51 from becoming turbulent. In other words, the diffuser plate 52 causes the after-shield gas to flow downward in a laminar flow.

[0055] The diffusion plate 52 may be fixed in the discharge portion 21 h by any method. For example, a groove may be formed in each of the pair of side shielding portions 21 c. The diffusion plate 52 is held in the discharge portion 21 h by fitting the outer periphery of the diffusion plate 52 into the groove.

[0056] The material constituting the diffusion plate 52 is not particularly limited, and may be, for example, iron, stainless steel, copper, aluminum, or ceramic.

[0057] There are no particular limitations on the shape, location, or number of the diffuser plates 52. As shown in Fig. 5, the diffuser plates 52 may be arranged in a direction perpendicular to the X direction. In this way, the after-shield gas supplied from the piping joint 51 is blown out onto the workpiece 200 through the diffuser plates 52.

[0058] The diffusion plate 52 does not have to be disposed in a direction perpendicular to the X direction. For example, the diffusion plate 52 may be disposed so as to be inclined with respect to the X direction as shown in FIG.

[0059] The number of diffuser plates 52 may be one, or multiple diffuser plates 52 may be arranged in the discharge section 21h. As shown in Fig. 7, the number of diffuser plates 52 may be, for example, two. Two diffuser plates 52 may be arranged side by side in the X direction.

[0060] The side shielding portion 21c has an upper surface, a front surface 25s2, a rear surface 25s1, and a lower surface 25. The upper surface is the surface opposite the lower surface 25. The lower surface 25 faces the workpiece 200. In other words, the upper surface and the lower surface 25 are both end surfaces in the Z direction. The front surface 25s2 is the surface opposite the rear surface 25s1. The rear surface 25s1 is the surface farthest from the welding torch 1 in the X direction. In other words, the front surface 25s2 and the rear surface 25s1 are both end surfaces in the X direction.

[0061] The shape of the side shielding portion 21c may be any shape, but it is preferable that the shape of the lower surface 25 conforms to the surface of the workpiece 200. As shown in FIG. 3 , the lower surface 25 may have a pair of horizontal portions 25a and an inclined portion 25b. In the X direction, the inclined portion 25b is positioned so as to be sandwiched between the pair of horizontal portions 25a. The pair of horizontal portions 25a are positioned spaced apart from each other in the Z direction. The pair of horizontal portions 25a are connected via the inclined portion 25b. The inclined portion 25b extends in a direction conforming to the surface of the workpiece 200. This reduces the gap between the shielding portion 21 and the workpiece 200. As a result, the after-shield gas is prevented from diffusing from the gap between the shielding portion 21 and the workpiece 200. As a result, the after-shield gas can sufficiently shield the welded portion A of the workpiece 200 from the atmosphere.

[0062] 8 and 9 are side views showing modified examples of side surface shielding portion 21c in welding device 100 according to embodiment 1. Welding device 100 shown in Fig. 8 and Fig. 9 basically has the same configuration as welding device 100 shown in Fig. 1 to Fig. 3, but is different in the shape of side surface shielding portion 21c.

[0063] The shape of the lower surface 25 may be any shape as long as it follows the surface of the workpiece 200. Therefore, the shape of the lower surface 25 may be, for example, a shape formed by combining a plurality of straight line portions 25c as shown in Fig. 8. The plurality of straight line portions 25c are arranged so as to be sandwiched between a pair of horizontal portions 25a. The lower surface 25 may have a curved surface portion 25d as shown in Fig. 9. The curved surface portion 25d is arranged so as to be sandwiched between a pair of horizontal portions 25a.

[0064] This makes it possible to further reduce the gap between the shielding portion 21 and the workpiece 200. As a result, the after-shield gas is prevented from diffusing from the gap between the shielding portion 21 and the workpiece 200. As a result, the after-shield gas can sufficiently shield the welded portion A of the workpiece 200 from the atmosphere.

[0065] Although the welding torch 1 may be disposed in any position, it is preferably disposed so as to be sandwiched between a pair of side shields 21c in the Y direction. Specifically, as shown in FIG. 3, in a side view of the welding device 100, the welding torch 1 and the electrode portion 1a preferably overlap the side shields 21c in the X direction. From a different perspective, the welding torch 1 is preferably disposed between the front surface 25s2 and the rear surface 25s1 of the side shields 21c in the X direction. In this manner, the after-shield gas, whose diffusion in the Y direction is suppressed by the side shields 21c, hits the weld A. Therefore, oxidation of the weld A is further suppressed.

[0066] FIG. 10 is a side view showing the positional relationship between side surface shield 21c and welding torch 1 in welding device 100 according to embodiment 1. As shown in FIG. 10 , in a side view of welding device 100, a portion of welding torch 1 does not have to overlap side surface shield 21c. Furthermore, in a side view of welding device 100, the entire welding torch 1 does not have to overlap side surface shield 21c. Specifically, in the X direction, welding torch 1 may be positioned farther away in the X direction than front surface 25s2 of side surface shield 21c when viewed from rear surface 25s1 of side surface shield 21c. In this manner, because electrode 1a of welding torch 1 is not covered by side surface shield 21c, the positional relationship between electrode 1a and workpiece 200 can be easily confirmed visually.

[0067] FIG. 11A is a side view showing a modified example of the first maintenance mechanism 22 in the welding apparatus 100 according to the first embodiment. The welding apparatus 100 shown in FIG. 11A basically has the same configuration as the welding apparatus 100 shown in FIGS. 1 to 3 , but differs in the structure of the first maintenance mechanism 22. The first maintenance mechanism 22 may have any structure. As shown in FIG. 11A , the first maintenance mechanism 22 is composed of a shaft 22c and a rotating roller 22d. The shaft 22c connects the first maintenance mechanism 22 and the side shielding portion 21c. The shaft 22c extends in the Y direction. The rotating roller 22d rotates around the shaft 22c as its central axis. As the workpiece 200 rotates, the rotating roller 22d can roll on the surface of the workpiece 200.

[0068] As described above, the side shielding portion 21c has a rear surface 25s1 and a front surface 25s2. The side shielding portion 21c is connected to the rear shielding portion 21b at the rear surface 25s1. The front surface 25s2 is located opposite the rear surface 25s1 in the X direction.

[0069] The first maintenance mechanism 22, including the shaft 22c and the rotating roller 22d, may be positioned so as to reduce the influence of heat generated by welding. Specifically, the central axis of the shaft 22c may be positioned in a region Q1 in the X direction. The region Q1 is a region extending from the rear surface 25s1 to 50 percent of the width L in the X direction. The width L may be the distance from the rear surface 25s1 to the front surface 25s2 in the X direction. The region Q1 may be a region extending from the rear surface 25s1 to the central axis 1c of the welding torch 1. In this manner, the rotating roller 22d is positioned near the rail 30, which allows the rotating roller 22d to roll more easily on the surface of the workpiece 200.

[0070] When the workpiece 200 is made up of two members (for example, the body portion 201 or the end portion 202 shown in FIG. 19 ), if either or both of the members have a distorted shape, the rotating roller 22d cannot sufficiently adjust the distance between the shielding portion 21 and the workpiece 200. Therefore, the first maintaining mechanism 22 may be connected to each of the pair of side shielding portions 21c so that the rotating roller 22d can come into contact with either of the members.

[0071] Fig. 11B is a side view showing a modified example of first maintenance mechanism unit 22 in welding device 100 according to embodiment 1. Fig. 11B corresponds to Fig. 11A. First maintenance mechanism unit 22 shown in Fig. 11B basically has the same configuration as first maintenance mechanism unit 22 shown in Fig. 11A, but differs in that position adjustment unit 23 is provided between side shielding unit 21c and first maintenance mechanism unit 22.

[0072] 11B, the position adjustment unit 23 may be, for example, a plate material. The plate material has a plurality of through holes h1, h2, and h3. Screws are inserted into the through holes h1, h2, and h3. In other words, by inserting a screw into one of the through holes h1, h2, and h3, the first maintenance mechanism unit 22 is fixed to the plate material via the screw.

[0073] The through holes h1 and h2 may be, for example, drilled holes formed using a drill. As shown in Fig. 11B, the opening shapes of the through holes h1 and h2 (the shapes of the through holes h1 and h2 as viewed from the Y direction) may be circular or elliptical.

[0074] The through-hole h1 is disposed apart from the through-hole h2 in the X direction. The position in the X direction at which the first maintenance mechanism 22 is fixed may be adjusted by inserting a screw into either the through-hole h1 or h2. In this manner, the relative position of the first maintenance mechanism 22 with respect to the side shielding portion 21c may be changed.

[0075] 11B, the opening of the through hole h3 may extend in the Z direction. Specifically, the width of the through hole h3 in the Z direction may be greater than its width in the X direction. In this manner, the through hole h3 may be an elongated hole extending in the Z direction. The position in the Z direction at which the first maintenance mechanism 22 is fixed may be adjusted by inserting a screw into the through hole h3 at any position in the Z direction. In this manner, the relative position of the first maintenance mechanism 22 with respect to the side shielding portion 21c may be changed.

[0076] The opening of the through hole h3 may extend in the X direction. Specifically, the width of the through hole h3 in the X direction may be larger than the width in the Z direction. In this way, the through hole h3 may be an elongated hole extending in the X direction.

[0077] Fig. 11C is a front view showing a modified example of first maintenance mechanism 22 in welding apparatus 100 according to embodiment 1. First maintenance mechanism 22 shown in Fig. 11C basically has the same configuration as first maintenance mechanism 22 shown in Figs. 1 to 3, but differs in that first maintenance mechanism 22 has an adjuster bolt mechanism. First maintenance mechanism 22 shown in Fig. 11C is a front view seen from the X direction.

[0078] As shown in FIG. 11C , the ball roller 22a is connected to, for example, a cylindrical part 22f. A through-hole may be formed in the second surface 22b2 of the bracket 22b. A male thread may be formed on the side of the cylindrical part 22f, and a female screw may be formed on the inner circumferential surface of the through-hole. The cylindrical part 22f is inserted into the through-hole of the bracket 22b. The cylindrical part 22f is movable in a direction perpendicular to the second surface 22b2 (e.g., along the Z direction). The cylindrical part 22f is fixed to the bracket 22b by a nut. In this manner, the relative position of the ball roller 22a of the first maintenance mechanism 22 with respect to the side shielding part 21c may be changed. Note that if scratches are allowed on the workpiece 200, such as the body part 201 or end part 202 shown in FIG. 19 , the ball roller 22a or the rotary roller 22d shown in FIGS. 11A to 11C may not be used. In this case, the distance between the shielding portion 21 and the workpiece 200 may be adjusted by bringing the side shielding portion 21c or the bracket 22b into direct contact with the workpiece 200.

[0079] Fig. 11D is a side view showing a modified example of side surface shielding part 21c in welding device 100 according to embodiment 1. Side surface shielding part 21c shown in Fig. 11D basically has the same configuration as side surface shielding part 21c shown in Figs. 1 to 3, but differs in that side surface shielding part 21c is provided with link member 23g.

[0080] The link member 23g may be a plate-shaped member. One side of the link member 23g follows the shape of the workpiece 200. A part of the side of the link member 23g may be in contact with the workpiece 200.

[0081] Link member 23g is connected to side shielding portion 21c via shaft portion 23g1. Link member 23g is provided with shaft portion 23g1. As shown in FIG. 11D, shaft portion 23g1 is disposed near the tip of welding torch 1. Link member 23g and side shielding portion 21c are connected by shaft portion 23g1. Shaft portion 23g1 extends in the Y direction. Link member 23g rotates around shaft portion 23g1 as a central axis.

[0082] A through hole h4 is provided in the link member 23g. The opening of the through hole h4 extends along the rotation direction of the link member 23g. A fixing member 23g2 is inserted into the through hole h4. The fixing member 23g2 may fix the position of the link member 23g relative to the side shielding portion 21c.

[0083] The first maintaining mechanism 22 is disposed near the rear surface 25s1 in the X direction. In this manner, the link member 23g further prevents the after-shield gas from diffusing from the gap between the shielding portion 21 and the workpiece 200. As a result, the after-shield gas can sufficiently shield the welded portion A of the workpiece 200 from the atmosphere without using the rail 30.

[0084] Fig. 11E is a side view showing a modified example of side surface shielding part 21c in welding device 100 according to embodiment 1. Side surface shielding part 21c shown in Fig. 11E basically has the same configuration as side surface shielding part 21c shown in Figs. 1 to 3, but differs in that side surface shielding part 21c has movable part 8.

[0085] Specifically, the side shielding portion 21c includes a main body portion 81 and a movable portion 82. The main body portion 81 is connected to the rear shielding portion 21b. The first maintaining mechanism portion 22 is connected to the main body portion 81.

[0086] The movable portion 82 is connected to the main body portion 81 via a coupling portion 84. In the X direction, the movable portion 82 is disposed opposite the rear surface 25s1. The movable portion 82 is formed by a plurality of connecting members 83. The connecting members 83 are connected to each other via the coupling portions 84.

[0087] Each of the multiple connecting members 83 can slide, for example, along the X and Z directions. Specifically, the connecting members 83 have fitting portions into which the coupling portions 84 fit. The fitting portions may be, for example, through holes extending in the X direction. The position of the connecting member 83 in the X direction is determined by the position at which the coupling portions 84 fit in the fitting portions. The connecting members 83 may rotate around the coupling portions 84. In this manner, the connecting members 83 can slide along the X and Y directions relative to adjacent connecting members 83. Therefore, as shown in FIG. 11E , the multiple connecting members 83 can be arranged so that the lower ends of the multiple connecting members 83 conform to the shape of the workpiece 200 (e.g., the body portion 201 or the end portion 202 shown in FIG. 19 ).

[0088] This further prevents the after-shield gas from diffusing from the gap between the shielding portion 21 and the workpiece 200. As a result, the after-shield gas can sufficiently shield the welded portion A of the workpiece 200 from the atmosphere.

[0089] FIG. 12 is a cross-sectional schematic diagram showing a modified example of the after-shield gas jig 10 in the welding apparatus 100 according to the first embodiment. FIG. 12 corresponds to FIG. 3. The welding apparatus 100 shown in FIG. 12 basically has the same configuration as the welding apparatus 100 shown in FIGS. 1 to 3, but differs in that the after-shield gas jig 10 includes a flame-retardant cover 24. As shown in FIG. 12, the cover 24 is connected to the gas supply unit 20. The covers 24 may be a pair. The pair of covers 24 are arranged outside the shielding portion 21 in the Y direction. Specifically, the pair of covers 24 may be arranged to sandwich the pair of side shielding portions 21c in the Y direction.

[0090] It is preferable that the cover 24 be disposed near the workpiece 200 when the workpiece 200 is welded so that the after-shield gas does not leak from the gap between the shielding portion 21 and the workpiece 200. In particular, as shown in Fig. 12, the cover 24 may be in contact with the workpiece 200. Therefore, the shape of the cover 24 may have notches formed at any positions so that the cover 24 conforms to the surface of the workpiece 200.

[0091] This further prevents the after-shield gas from diffusing from the gap between the shielding portion 21 and the workpiece 200. As a result, the after-shield gas can sufficiently shield the welded portion A of the workpiece 200 from the atmosphere.

[0092] When welding the workpiece 200, the heat generated by the welding may cause the workpiece 200 to reach a high temperature. Therefore, it is preferable that the cover 24 has flame retardancy. In particular, it is preferable that the material constituting the cover 24 is, for example, glass fiber, ceramic fiber, or carbon fiber.

[0093] If the cover 24 is in contact with the workpiece 200, wear and heat from welding will accelerate deterioration of the cover 24. Therefore, when welding the workpiece 200, the cover 24 does not need to be in contact with the workpiece 200.

[0094] FIG. 13 is a perspective view showing a modified example of the after-shield gas jig 10 in the welding apparatus 100 according to the first embodiment. FIG. 13 corresponds to FIG. 1. The welding apparatus 100 shown in FIG. 13 basically has the same configuration as the welding apparatus 100 shown in FIGS. 1 to 3, but differs in that the shielding portion 21 includes a front shielding portion 21d. Specifically, the front shielding portion 21d is connected to the front surfaces of the pair of side shielding portions 21c. The welding torch 1 is disposed between the convex portion 21g of the top shielding portion 21a and the front shielding portion 21d in the X direction. In this manner, the after-shield gas can sufficiently shield the weld zone A of the workpiece 200 from the atmosphere.

[0095] The material constituting the after-shield gas jig 10 may be, for example, iron, stainless steel, copper, aluminum, or ceramic. Furthermore, a plurality of after-shield gas jigs 10 may be provided in the welding apparatus 100.

[0096] <Action and Effect> The after-shield gas jig 10 according to the present disclosure includes a gas supply unit 20. The gas supply unit 20 has an exhaust unit 21h. The exhaust unit 21h is capable of blowing out the after-shield gas toward the workpiece 200. The gas supply unit 20 has a shielding unit 21 and a first maintaining mechanism unit 22. When viewed from the direction in which the after-shield gas is blown out, the shielding unit 21 is disposed to surround the exhaust unit 21h. The first maintaining mechanism unit 22 can maintain a constant distance between the shielding unit 21 and the workpiece 200, independent of the position of the welding torch 1.

[0097] In this way, the distance between shielding portion 21 and workpiece 200 is maintained constant, independent of the position of welding torch 1. This prevents the after-shield gas from diffusing from the gap between shielding portion 21 and workpiece 200. As a result, the after-shield gas can sufficiently shield weld zone A of workpiece 200 from the atmosphere.

[0098] The after-shield gas jig 10 includes a rail 30 and a first connection part 40. The rail 30 is connected to the gas supply part 20. The first connection part 40 is slidable on the rail 30. The first connection part 40 can hold the welding torch 1. In this manner, the distance between the shielding part 21 and the workpiece 200 is maintained constant by the first maintaining mechanism part 22 regardless of the position of the welding torch 1.

[0099] The after-shield gas jig 10 includes a cover 24. The cover 24 is connected to the gas supply unit 20. The cover 24 is flame-retardant. In this manner, the cover 24 can be placed near the workpiece 200 when welding the workpiece 200. In other words, the after-shield gas is prevented from diffusing from the gap between the shielding unit 21 and the workpiece 200. As a result, the after-shield gas can sufficiently shield the welded portion A of the workpiece 200 from the atmosphere.

[0100] In the after-shield gas jig 10, the material constituting the cover 24 includes any one of glass fiber, ceramic fiber, and carbon fiber. In this way, the cover 24 can be placed near the workpiece 200 when welding the workpiece 200. As a result, the after-shield gas can sufficiently shield the welded portion A of the workpiece 200 from the atmosphere.

[0101] Welding apparatus 100 according to the present disclosure includes welding torch 1 and after-shield gas jig 10. In this manner, the distance between shielding portion 21 and workpiece 200 is maintained constant, independent of the position of welding torch 1. This prevents the after-shield gas from diffusing from the gap between shielding portion 21 and workpiece 200. As a result, the after-shield gas can sufficiently shield weld zone A of workpiece 200 from the atmosphere.

[0102] Embodiment 2. <Configuration of Welding Apparatus> Figure 14 is a cross-sectional perspective view showing gas supply unit 20 in welding apparatus 100 according to embodiment 2. Welding apparatus 100 shown in Figure 14 basically has the same configuration as welding apparatus 100 shown in Figures 1 to 3, but differs in the structure of gas supply unit 20. Specifically, upper surface shielding portion 21a is not L-shaped but is flat, as shown in Figure 14. Unlike upper surface shielding portion 21a shown in Figure 2, no convex portion 21g is formed in upper surface shielding portion 21a according to embodiment 2.

[0103] Grooves are formed in each of the top shielding portion 21 a, the rear shielding portion 21 b, and the pair of side shielding portions 21 c. As shown in Fig. 14 , the filter 21 f is held in the discharge portion 21 h so that the outer periphery of the filter 21 f fits into the grooves of the top shielding portion 21 a, the rear shielding portion 21 b, and the pair of side shielding portions 21 c. Therefore, as shown in Fig. 14 , the shape of the filter 21 f has a curved portion when viewed from the side.

[0104] In this manner, the after-shield gas supplied from piping joint 51 can be blown out in a direction perpendicular to the tangent of workpiece 200 and in a direction along the tangent. Note that the direction along the tangent means a direction parallel to the tangent and a direction inclined at an angle of 30° or less with respect to the tangent. Specifically, the after-shield gas is blown out in directions along the X and Z directions through filter 21f. As a result, welding apparatus 100 according to the second embodiment can blow out the after-shield gas toward workpiece 200 over a wider range than welding apparatus 100 according to the first embodiment.

[0105] <Effects> In the after-shield gas jig 10, the after-shield gas can be blown out in a direction perpendicular to the tangent line of the workpiece 200 and in a direction along the tangent line. In this way, the after-shield gas can be supplied over a wide area of ​​the workpiece 200. As a result, the after-shield gas can sufficiently shield the welded portion A of the workpiece 200 from the atmosphere.

[0106] Embodiment 3. <Configuration of the Welding Apparatus> Figures 15A and 16 are cross-sectional perspective views showing gas supply unit 20 in welding apparatus 100 according to embodiment 3. Figures 15A and 16 correspond to Figure 14. Welding apparatus 100 shown in Figures 15A and 16 basically has the same configuration as welding apparatus 100 shown in Figure 14, but differs in that welding torch 1 is disposed at an angle relative to workpiece 200. Specifically, as shown in Figure 15A, an inclined portion 26 is formed on the upper surface of upper shielding portion 21a. Inclined portion 26 is disposed at a corner of upper shielding portion 21a that is close to welding torch 1. Inclined portion 26 is the surface on which welding torch 1 is mounted.

[0107] As shown in FIG. 16 , the welding torch 1 is placed on the inclined portion 26. The arm portion 44 (not shown) is positioned so as to hold the inclined welding torch 1. In this manner, the position of the weld A becomes farther away. However, in a side view of the filter 21f, the shape of the filter 21f has a curved portion. Therefore, the after-shield gas supplied from the piping joint 51 is blown out in a direction perpendicular to the tangent line of the workpiece 200 and in a direction along the tangent line. As a result, the after-shield gas can sufficiently shield the weld A of the workpiece 200 from the atmosphere.

[0108] The welding torch 1 is inclined relative to the workpiece 200. From a different perspective, the central axis 1c of the electrode portion 1a is inclined relative to the tangent line of the workpiece 200. In this way, the pressure of the arc applied to the weld A is dispersed not only in a direction perpendicular to the tangent line of the workpiece 200 (Z direction) but also in a direction parallel to the tangent line (X direction). As a result, the pressure applied to the weld A in the Z direction is reduced, and the weld A is prevented from forming a weld pool and melting through.

[0109] The gas supply unit 20 shown in FIGS. 15A and 16 may include the diffusion plate 52 shown in FIGS. 5 to 7 (not shown).

[0110] The rail 30 may be inclined (not shown) along the central axis 1c of the welding torch 1. From a different perspective, the rail 30 may extend along the central axis 1c of the welding torch 1. In this way, the welding torch 1 and the gas supply unit 20 can move along the central axis 1c of the welding torch 1 independently of each other.

[0111] Furthermore, when the welding torch 1 is positioned at an angle, as described above in FIG. 10, in a side view of the welding apparatus 100, a portion of the welding torch 1 does not have to overlap the side shielding portion 21c, and the entire welding torch 1 does not have to overlap the side shielding portion 21c.

[0112] The inclined portion 26 is formed by a flat surface. The shape of the surface forming the inclined portion 26 may be changed in accordance with the outer peripheral shape of the welding torch 1.

[0113] Fig. 15B is a cross-sectional perspective view showing a modified example of gas supply unit 20 in welding device 100 according to embodiment 3. Fig. 15B corresponds to Fig. 15A. Gas supply unit 20 shown in Fig. 15B basically has the same configuration as gas supply unit 20 shown in Fig. 15A, but differs in that inclined portion 26 is formed by a curved surface. Specifically, inclined portion 26 has a concave shape extending in a direction away from welding torch 1.

[0114] As shown in Figure 16, the welding torch 1 is cylindrical. From a different perspective, the outer peripheral shape of the welding torch 1 is circular. When the outer peripheral shape of the welding torch 1 is circular in this way, the gap formed between the inclined portion 26 and the welding torch 1 is small. As a result, the after-shield gas is prevented from diffusing from the gap. Furthermore, the air is prevented from flowing into the weld A from the gap.

[0115] As shown in FIG. 15B, the gas supply section 20 may include the diffuser plate 52 shown in FIGS.

[0116] <Effects> In the above-described welding device 100, the welding torch 1 has an electrode portion 1a. The central axis 1c of the electrode portion 1a is inclined with respect to the tangent line of the workpiece 200. This reduces the pressure applied to the welded portion A by the arc. As a result, the welded portion A is prevented from forming a weld pool and melting through.

[0117] Embodiment 4. <Configuration of Welding Apparatus> FIG. 17 is a perspective view of welding apparatus 100 according to embodiment 4. FIG. 17 corresponds to FIG. 1. Welding apparatus 100 shown in FIG. 17 basically has the same configuration as welding apparatus 100 shown in FIG. 1, but differs in that the distance between welding torch 1 and workpiece 200 is adjusted by a maintenance mechanism, independently of the position of shielding portion 21. Specifically, welding apparatus 100 includes a second connection portion 40y and a pair of rails 30y. Second connection portion 40y is connected to welding torch 1. As shown in FIG. 17, the second connection portion 40y basically has the same configuration as first connection portion 40x. Second connection portion 40y can hold welding torch 1. Second connection portion 40y includes a sliding portion 41y, a first block portion 42y, a second block portion 43y (not shown), an arm portion 44y, and a third block portion 45y.

[0118] The sliding portion 41y is connected to the rail 30y and is capable of sliding on the rail 30y. The first block portion 42y is connected to be fixed to the sliding portion 41y. The second block portion 43y is connected to be fixed to the first block portion 42y. The arm portion 44y is connected to be fixed to the second block portion 43y. The arm portion 44y can hold the welding torch 1.

[0119] The third block portion 45y is fixedly connected to the arm portion 44y. As shown in Fig. 17, the third block portion 45y has a rectangular shape in a side view of the welding device 100. The third block portion 45y extends in the Z direction.

[0120] The rail 30y is connected to the drive unit 2 so as to be fixed thereto. Each of the pair of rails 30y has a stopper 31y. The stopper 31y is disposed at the upper end of the rail 30y. This prevents the sliding portion 41y from coming off the rail 30y.

[0121] The second connection portion 40y has a second maintenance mechanism 22y as a maintenance mechanism. The second maintenance mechanism 22y has a configuration similar to that of the first maintenance mechanism 22x, but differs in that the second maintenance mechanism 22y is connected to be fixed to the third block portion 45y. The second maintenance mechanism 22y maintains a constant distance between the welding torch 1 and the workpiece 200.

[0122] In this manner, the distance between the welding torch 1 and the workpiece 200 is maintained constant by the second maintaining mechanism 22y. Meanwhile, the distance between the shielding part 21 and the workpiece 200 is maintained constant by the first maintaining mechanism 22x. In other words, the relative positions of the shielding part 21 and the welding torch 1 with respect to the workpiece 200 are determined independently of each other. As a result, even if the workpiece 200 is displaced due to eccentricity or the like, the relative positions of the welding torch 1 and the shielding part 21 with respect to the workpiece 200 do not change and are maintained constant, even if the workpiece 200 is rotating.

[0123] <Effects> The welding device 100 includes a second connection part 40y. The second connection part 40y is connected to the welding torch 1. The second connection part 40y has a second maintenance mechanism 22y. The second maintenance mechanism 22y can maintain a constant distance between the welding torch 1 and the workpiece 200. In this manner, the distance between the welding torch 1 and the workpiece 200 is maintained constant by the second maintenance mechanism 22y. In other words, the relative positions of the shielding part 21 and the welding torch 1 with respect to the workpiece 200 are determined independently of each other. As a result, even if the workpiece 200 is displaced due to eccentricity or the like, the relative positions of the welding torch 1 and the shielding part 21 with respect to the workpiece 200 do not change and are maintained constant, even if the workpiece 200 is rotating.

[0124] <Configuration of Modified Example> Fig. 18 is a schematic diagram for explaining the configuration of a modified example of welding device 100 according to embodiment 4. Welding device 100 shown in Fig. 18 basically has the same configuration as welding device 100 shown in Fig. 17 , but differs in that the distance between welding torch 1 and workpiece 200 is adjusted based on the voltage of the arc generated from electrode portion 1a of welding torch 1. Specifically, welding device 100 includes processing circuit 3. As shown in Fig. 18, processing circuit 3 includes control unit 3a and detection unit 3b.

[0125] The detector 3b is connected to the controller 3a. The detector 3b detects the voltage of the arc generated from the electrode 1a of the welding torch 1. A voltage sensor that measures the voltage of the arc can be used as the detector 3b. When the workpiece 200 is displaced due to eccentricity or the like, the distance (arc length) between the workpiece 200 and the welding torch 1 changes, resulting in a change in the voltage of the arc.

[0126] Control unit 3a controls drive unit 2 in accordance with the arc voltage detected by detection unit 3b. Specifically, control unit 3a controls drive unit 2 so that the arc voltage approaches a preset voltage. As a result, drive unit 2 can change the position of welding torch 1 relative to workpiece 200. This allows the position of welding torch 1, i.e., the position of electrode unit 1a, to be adjusted.

[0127] In this way, the distance between welding torch 1 and workpiece 200 may be adjusted based on the voltage of the arc generated from electrode 1 a, independently of the position of shielding part 21. In other words, the relative positions of shielding part 21 and welding torch 1 with respect to workpiece 200 are determined independently of each other. As a result, if workpiece 200 is displaced due to eccentricity or the like, the relative positions of welding torch 1 and shielding part 21 with respect to workpiece 200 do not change, but are maintained constant or adjusted, even if workpiece 200 is rotating.

[0128] <Operation and Effect> The welding device 100 includes a drive unit 2 and a processing circuit 3. The drive unit 2 is connected to the welding torch 1. The processing circuit 3 detects the voltage of the arc generated from the electrode 1 a of the welding torch 1. The drive unit 2 adjusts the distance between the welding torch 1 and the workpiece 200 based on the voltage.

[0129] In this way, the distance between welding torch 1 and workpiece 200 is adjusted based on the voltage of the arc generated from electrode 1 a, independently of the position of shielding portion 21. In other words, the relative positions of shielding portion 21 and welding torch 1 with respect to workpiece 200 are determined independently of each other.

[0130] Fifth Embodiment <Configuration of Welding Equipment> Figure 19 is a schematic diagram of welding equipment 300 according to a fifth embodiment. The welding equipment 300 shown in Figure 19 is used to weld a cylindrical structure as a workpiece 200. The cylindrical structure may be, for example, a hot water tank for a water heater. The hot water tank is composed of a body 201 and a pair of end portions 202. The body 201 is, for example, a cylindrical thin plate manufactured by roll forming. The end portions 202 are bowl-shaped thin plates. The material constituting the hot water tank may be, for example, a steel plate such as stainless steel.

[0131] Body portion 201 is arranged so as to be sandwiched between a pair of end portions 202. End portions 202 are welded to the end surface of body portion 201 by welding equipment 300. In other words, the location where body portion 201 and end portions 202 are connected becomes welded portion A.

[0132] Welding equipment 300 mainly includes welding device 100 according to any one of embodiments 1 to 4, a holding mechanism 301, and a rotation mechanism 302. Holding mechanism 301 holds workpiece 200. Rotation mechanism 302 rotates workpiece 200. In this fifth embodiment, holding mechanism 301 holds end portion 202. End portion 202 is connected to body portion 201. That is, body portion 201 is held by welding equipment 300 with end portions 202 in contact with both ends of body portion 201. Workpiece 200 is welded while body portion 201 and the pair of end portions 202 are rotated by rotation mechanism 302. In this manner, a hot water storage tank is manufactured in which body portion 201 and the pair of end portions 202 are integrally assembled.

[0133] <Welding Method> Next, a welding method using the welding equipment 300 including the second maintenance mechanism 22y shown in FIG. 17 will be described.

[0134] First, a preparation step is performed. In this step, workpiece 200 and welding equipment 300 are prepared as shown in FIG. 19. Welding device 100 has second holding mechanism 22y shown in FIG. 17. Workpiece 200 is a cylindrical structure or can body such as a hot water storage tank composed of a body 201 and a pair of end portions 202. Workpiece 200 is held by holding mechanism 301 with end portions 202 in contact with both ends of body 201.

[0135] Next, a moving step is performed. In this step, the workpiece 200 is moved near the welding device 100. Specifically, the workpiece 200 is moved so as to come into contact with the first maintaining mechanism 22x and the second maintaining mechanism 22y. Each of the first maintaining mechanism 22x and the second maintaining mechanism 22y is in contact with the surface of either the body portion 201 or the end portion 202.

[0136] Next, the welding process is performed. In this process, the workpiece 200 is welded. Specifically, the workpiece 200 is rotated by the rotation mechanism 302. The welding torch 1 generates an arc toward the workpiece 200. The after-shield gas is blown toward the workpiece 200 from the gas supply unit 20. If the workpiece 200 is displaced due to eccentricity or the like, the first maintenance mechanism 22x maintains a constant distance between the shield 21 and the workpiece 200 even as the workpiece 200 rotates. The second maintenance mechanism 22y also maintains a constant distance between the welding torch 1 and the workpiece 200. In other words, the relative positions of the shield 21 and the welding torch 1 with respect to the workpiece 200 are determined independently. Therefore, the body 201 and the end 202 are welded while the weld zone A of the workpiece 200 is sufficiently shielded from the atmosphere by the after-shield gas.

[0137] In this manner, a hot water storage tank is manufactured in which the body portion 201 and the pair of end portions 202 are assembled together.

[0138] <Welding Method> Next, a welding method using welding equipment 300 including processing circuit 3 shown in FIG. 18 will be described.

[0139] First, a preparation step is carried out. In this step, workpiece 200 and welding equipment 300 are prepared as shown in Fig. 19. Welding device 100 includes processing circuit 3 shown in Fig. 18. Workpiece 200 is a hot water storage tank composed of body 201 and a pair of end portions 202. Workpiece 200 is held by holding mechanism 301 with end portions 202 in contact with both ends of body 201.

[0140] Next, a moving step is performed. In this step, the workpiece 200 is moved near the welding device 100. Specifically, the workpiece 200 is moved so as to come into contact with the first maintaining mechanism 22. The first maintaining mechanism 22 is in contact with the surface of either the body portion 201 or the end portion 202.

[0141] Next, a welding process is performed. In this process, the workpiece 200 is welded. Specifically, the workpiece 200 is rotated by the rotation mechanism 302. The welding torch 1 generates an arc toward the workpiece 200. After-shield gas is blown toward the workpiece 200 from the gas supply unit 20. If the workpiece 200 is displaced due to eccentricity or the like, the first maintenance mechanism 22 maintains a constant distance between the shielding unit 21 and the workpiece 200 even while the workpiece 200 is rotating. Meanwhile, the drive unit 2 adjusts the distance between the welding torch 1 and the workpiece 200. Specifically, the distance between the welding torch 1 and the workpiece 200 is adjusted based on the voltage of the arc generated by the electrode 1a. In other words, the relative positions of the shielding unit 21 and the welding torch 1 with respect to the workpiece 200 are determined independently of each other. Therefore, the body portion 201 and the end portion 202 are welded together while the weld zone A of the workpiece 200 is sufficiently shielded from the atmosphere by the after-shield gas.

[0142] In this manner, a hot water storage tank is manufactured in which the body portion 201 and the pair of end portions 202 are assembled together.

[0143] <Operation and Effect> The welding equipment 300 according to the present disclosure includes the welding device 100, a holding mechanism 301, and a rotation mechanism 302. The holding mechanism 301 holds the workpiece 200. The rotation mechanism 302 rotates the workpiece 200.

[0144] In this way, a cylindrical structure such as a hot water storage tank can be welded while the relative positions of the shielding portion 21 and the welding torch 1 with respect to the workpiece 200 are determined independently of each other. At this time, the after-shield gas sufficiently shields the welded portion A of the workpiece 200 from the atmosphere.

[0145] A welding method according to the present disclosure includes a step of moving a workpiece 200 near a welding device 100 and a step of welding the workpiece 200. In the moving step, the workpiece 200 is moved so as to come into contact with a first maintaining mechanism 22x. In the welding step, the welding torch 1 generates an arc toward the workpiece 200. In the welding step, after-shield gas is blown from the gas supply unit 20 toward the workpiece 200. In the welding step, the first maintaining mechanism 22x maintains a constant distance between the shielding unit 21 and the workpiece 200. In the welding step, the second maintaining mechanism 22y maintains a constant distance between the welding torch 1 and the workpiece 200.

[0146] In this way, a cylindrical structure such as a hot water storage tank can be welded while the relative positions of the shielding portion 21 and the welding torch 1 with respect to the workpiece 200 are determined independently of each other. At this time, the after-shield gas sufficiently shields the welded portion A of the workpiece 200 from the atmosphere.

[0147] A welding method according to the present disclosure includes a step of moving workpiece 200 near welding device 100 and a step of welding workpiece 200. In the moving step, workpiece 200 is moved so as to come into contact with first maintaining mechanism 22. In the welding step, welding torch 1 generates an arc toward workpiece 200. In the welding step, after-shield gas is blown from gas supply unit 20 toward workpiece 200. In the welding step, first maintaining mechanism 22 maintains a constant distance between shielding unit 21 and workpiece 200. In the welding step, drive unit 2 adjusts the distance between welding torch 1 and workpiece 200.

[0148] In this way, a cylindrical structure such as a hot water storage tank can be welded while the relative positions of the shielding portion 21 and the welding torch 1 with respect to the workpiece 200 are determined independently of each other. At this time, the after-shield gas sufficiently shields the welded portion A of the workpiece 200 from the atmosphere.

[0149] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. Unless there is a contradiction, at least two of the embodiments disclosed herein may be combined. The basic scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0150] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) An after-shield gas tool comprising a gas supply unit having an exhaust unit capable of blowing after-shield gas toward a workpiece, the gas supply unit having a shielding unit and a first maintenance mechanism unit, wherein, when viewed from the direction in which the after-shield gas is blown out, the shielding unit is disposed to surround the exhaust unit, and the first maintenance mechanism unit can maintain a constant distance between the shielding unit and the workpiece independently of the position of a welding torch. (Appendix 2) An after-shield gas tool according to Appendix 1, comprising: a rail connected to the gas supply unit; and a first connection unit slidable on the rail, the first connection unit being capable of holding a welding torch. (Appendix 3) An after-shield gas tool according to Appendix 1 or Appendix 2, comprising a cover connected to the gas supply unit, the cover being flame-retardant. (Appendix 4) An after-shield gas tool according to Appendix 3, wherein a material constituting the cover includes any one of glass fiber, ceramic fiber, and carbon fiber. (Supplementary Note 5) The after-shield gas tool according to any one of Supplementary Notes 1 to 4, wherein the after-shield gas can be blown out in a direction perpendicular to a tangent to the workpiece and in a direction along the tangent. (Supplementary Note 6) The after-shield gas tool according to any one of Supplementary Notes 1 to 5, wherein, when the direction in which the welding torch is disposed as viewed from the discharge part is defined as an X direction, the shielding part has a front face and a rear face that is the face opposite to the front face in the X direction, and the first maintenance mechanism part includes a rotating roller that is disposed in a region whose distance from the rear face is 50% or less of the distance in the X direction from the rear face to the front face, or in a region from the rear face to the welding torch. (Supplementary Note 7) The after-shield gas tool according to any one of Supplementary Notes 1 to 6, wherein a position adjustment part is provided between the shielding part and the first maintenance mechanism part, and the position adjustment part changes the relative position of the first maintenance mechanism part with respect to the shielding part. (Supplementary Note 8) The after-shield gas tool according to any one of Supplementary Note 1 to Supplementary Note 7, wherein a link member is provided on the shielding portion, and the relative position of the link member with respect to the shielding portion changes.(Supplementary Note 9) The after-shield gas tool according to any one of Supplementary Notes 1 to 8, wherein the shielding portion includes a movable portion that can slide. (Supplementary Note 10) The after-shield gas tool according to any one of Supplementary Notes 1 to 9, wherein the shielding portion has an inclined portion on which the welding torch is mounted. (Supplementary Note 11) The after-shield gas tool according to Supplementary Note 10, wherein the inclined portion is formed by a curved surface. (Supplementary Note 12) A welding device comprising the welding torch and the after-shield gas tool according to any one of Supplementary Notes 1 to 11. (Supplementary Note 13) The welding device according to Supplementary Note 12, wherein the welding torch has an electrode portion, and wherein a central axis of the electrode portion is inclined with respect to a tangent to the workpiece. (Supplementary Note 14) The welding device according to Supplementary Note 12 or Supplementary Note 13, further comprising: a second connection part connected to the welding torch, the second connection part having a second maintenance mechanism part, and the second maintenance mechanism part being able to maintain a constant distance between the welding torch and the workpiece. (Supplementary Note 15) The welding device according to any one of Supplementary Notes 12 to 14, further comprising: a drive part connected to the welding torch; and a processing circuit that detects a voltage of an arc generated from the welding torch, and the drive part adjusts the distance between the welding torch and the workpiece based on the voltage. (Supplementary Note 16) The welding device according to any one of Supplementary Notes 12 to 15, wherein, when the direction in which the welding torch is arranged as viewed from the discharge section is defined as the X direction, the shielding section has a front surface and a rear surface that is the surface opposite to the front surface in the X direction, and the first maintenance mechanism includes a rotating roller that is arranged in an area whose distance from the rear surface is 50% or less of the distance in the X direction from the rear surface to the front surface, or in an area from the rear surface to the welding torch. (Supplementary Note 17) The welding device according to any one of Supplementary Notes 12 to 16, wherein a position adjustment section is provided between the shielding section and the first maintenance mechanism, and the position adjustment section changes the relative position of the first maintenance mechanism with respect to the shielding section. (Supplementary Note 18) The welding device according to any one of Supplementary Notes 12 to 17, wherein a link member is provided on the shielding section, and the relative position of the link member with respect to the shielding section is changeable.(Supplementary Note 19) The welding device according to any one of Supplementary Notes 12 to 18, wherein the shielding section includes a movable section that can slide. (Supplementary Note 20) The welding device according to any one of Supplementary Notes 12 to 19, wherein the shielding section has an inclined section on which the welding torch is mounted. (Supplementary Note 21) The welding device according to Supplementary Note 20, wherein the inclined section is formed by a curved surface. (Supplementary Note 22) Welding equipment comprising the welding device according to any one of Supplementary Notes 12 to 21, a holding mechanism that holds the workpiece, and a rotation mechanism that rotates the workpiece. (Supplementary Note 23) A welding method comprising the steps of: moving the workpiece near the welding device according to Supplementary Note 14; and welding the workpiece; wherein in the moving step, the workpiece is moved so as to come into contact with the first maintaining mechanism; and in the welding step, the welding torch generates an arc toward the workpiece; the after-shield gas is blown from the gas supply unit toward the workpiece; the first maintaining mechanism maintains a constant distance between the shielding unit and the workpiece; and the second maintaining mechanism maintains a constant distance between the welding torch and the workpiece. (Supplementary Note 24) A welding method comprising the steps of: moving the workpiece near the welding device according to Supplementary Note 15; and welding the workpiece, wherein in the moving step, the workpiece is moved so as to come into contact with the first maintaining mechanism, and in the welding step, the welding torch generates an arc toward the workpiece, the after-shield gas is blown from the gas supply unit toward the workpiece, the first maintaining mechanism maintains a constant distance between the shielding unit and the workpiece, and the drive unit adjusts the distance between the welding torch and the workpiece. (Supplementary Note 25) The welding method according to Supplementary Note 23 or Supplementary Note 24, wherein the workpiece is a cylindrical structure. (Supplementary Note 26) A method for manufacturing a cylindrical structure using the welding method according to any one of Supplementary Notes 23 to 25, wherein the workpiece is a body portion and a pair of end portions that constitute the cylindrical structure.

[0151] 1 Welding torch, 1a Electrode portion, 1c Central axis, 2 Drive portion, 3 Processing circuit, 3a Control portion, 3b Detection portion, 10 After-shield gas jig, 20 Gas supply portion, 21 Shielding portion, 21a Upper shielding portion, 21b Rear shielding portion, 21c Side shielding portion, 21d Front shielding portion, 21f Filter, 21g Convex portion, 21h Discharge portion, 21r, 25d Curved portion, 21s Discharge surface, 22, 22x First maintenance mechanism portion, 22a Ball roller, 22b Bracket, 22c Shaft portion, 22d Rotating roller, 22f Cylindrical part, 22y Second maintenance mechanism portion, 23 Position adjustment portion, 23g Link member, 23g1 Shaft portion, 23g2 Fixing member, 24 Cover, 25 Lower surface, 25a Horizontal portion, 25b, 26 Inclined portion, 25c Straight portion, 25s1 Rear surface, 25s2 Front surface, 30, 30y Rail, 31, 31y Stopper, 40, 40x First connecting portion, 40y Second connecting portion, 41, 41y Sliding portion, 42, 42y First block portion, 43, 43y Second block portion, 44, 44y Arm portion, 45y Third block portion, 51 Pipe joint, 52 Diffuser, 81 Main body portion, 82 Movable portion, 83 Connecting member, 84 Joint portion, 100 Welding device, 200 Workpiece, 201 Body portion, 202 End portion, 300 Welding equipment, 301 Holding mechanism portion, 302 Rotation mechanism portion, A Welding portion, Q1 Region, h1, h2, h3, h4 Through hole.

Claims

1. a gas supply unit having an outlet that can blow out an after-shield gas toward the workpiece; the gas supply unit has a shielding unit and a first maintenance mechanism unit, When viewed from the direction in which the after-shield gas is blown out, the shielding portion is disposed so as to surround the discharge portion, An after-shield gas jig in which the first maintaining mechanism part comes into contact with the workpiece, thereby enabling the distance between the shielding part and the workpiece to be maintained constant independently of the position of the welding torch.

2. a rail connected to the gas supply; a first connection portion slidable on the rail; The after-shield gas fixture according to claim 1 , wherein the first connecting portion is capable of holding a welding torch.

3. a cover connected to the gas supply unit; The after-shield gas tool according to claim 1 , wherein the cover is flame-retardant.

4. The after-shield gas jig according to claim 3 , wherein the material constituting the cover includes any one of glass fiber, ceramic fiber, and carbon fiber.

5. 2. The after-shield gas tool according to claim 1, wherein the after-shield gas can be blown out in a direction perpendicular to a tangent line of the workpiece and in a direction along the tangent line.

6. If the direction in which the welding torch is disposed as viewed from the discharge portion is defined as the X direction, the shielding portion has a front surface and a rear surface that is a surface opposite to the front surface in the X direction, 2. The after-shield gas tool according to claim 1, wherein the first maintenance mechanism includes a rotating roller arranged in a region where a distance from the rear surface is 50 percent or less of a distance in the X direction from the rear surface to the front surface, or in a region from the rear surface to the welding torch.

7. a position adjustment unit is provided between the shielding unit and the first maintenance mechanism unit, The after-shield gas tool according to claim 1 , wherein the position adjustment part changes the relative position of the first maintaining mechanism part with respect to the shielding part.

8. a link member is provided on the shielding portion, The after-shield gas tool according to claim 1 , wherein the position of the link member relative to the shielding portion is variable.

9. The after-shield gas tool according to claim 1 , wherein the shielding portion includes a movable portion that is capable of sliding.

10. The after-shield gas jig according to claim 1 , wherein the shielding portion has an inclined portion on which the welding torch is mounted.

11. The after-shield gas tool according to claim 10 , wherein the inclined portion is formed by a curved surface.

12. the welding torch; A welding device comprising the after-shield gas jig according to any one of claims 1 to 11.

13. The welding torch has an electrode portion, The welding device according to claim 12, wherein the central axis of the electrode portion is inclined with respect to a tangent to the workpiece.

14. a second connection portion connected to the welding torch; the second connection portion has a second maintenance mechanism portion, The welding device according to claim 12, wherein the second maintaining mechanism can maintain a constant distance between the welding torch and the workpiece.

15. a drive unit connected to the welding torch; a processing circuit for detecting a voltage of an arc generated from the welding torch; The welding device according to claim 12 , wherein the driving unit adjusts the distance between the welding torch and the workpiece based on the voltage.

16. The welding device according to claim 12; a holding mechanism for holding the workpiece; and a rotation mechanism that rotates the workpiece.

17. moving the workpiece adjacent to the welding device of claim 14; and welding the workpieces. In the moving step, the workpiece is moved so as to come into contact with the first maintaining mechanism; In the welding step, the welding torch generates an arc toward the workpiece; the after-shield gas is blown from the gas supply portion toward the workpiece, the first maintaining mechanism maintains a constant distance between the shielding part and the workpiece, A welding method, wherein the second maintaining mechanism maintains a constant distance between the welding torch and the workpiece.

18. moving the workpiece adjacent to the welding device of claim 15; and welding the workpieces. In the moving step, the workpiece is moved so as to come into contact with the first maintaining mechanism; In the welding step, the welding torch generates an arc toward the workpiece; the after-shield gas is blown from the gas supply portion toward the workpiece, the first maintaining mechanism maintains a constant distance between the shielding part and the workpiece, A welding method, wherein the driving unit adjusts the distance between the welding torch and the workpiece.

19. 18. The method of claim 17, wherein the workpiece is a cylindrical structure.

20. A method for manufacturing a cylindrical structure using the welding method according to claim 17, A method for manufacturing a cylindrical structure, wherein the workpiece is a body portion and a pair of end portions that constitute the cylindrical structure.