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

TITLE OF INVENTION: After-Shield Gas Jig, Welding Device, Welding Equipment, Welding Method, and Method for Manufacturing Cylindrical Structure TECHNICAL FIELD

[0001] The present disclosure relates to a post shielding gas jig, a welding apparatus, a welding equipment, a welding method, and a method of manufacturing a cylindrical structure. BACKGROUND ART

[0002] Conventionally, a welding apparatus used for manufacturing a cylindrical structure or the like may include a rotatable roller that keeps a constant distance between a welding torch and a workpiece. A post shielding gas jig for supplying a post shielding gas has a shielding portion. In order to suppress oxidation of a weld bead, the shielding portion suppresses diffusion of the post shielding gas (see, for example, Japanese Patent Laying-Open No. 2022-149068). CITATION LIST PATENT LITERATURE

[0003] PTL 1: Japanese Patent Laying-Open No. 2022-149068 SUMMARY OF INVENTION TECHNICAL PROBLEM

[0004] However, in such a welding apparatus as described above, while the distance between the shielding portion and a workpiece is kept constant by the rotatable roller, the post shielding gas jig moves together with the welding torch, and therefore, the relative position of the shielding portion with respect to the workpiece is not appropriately set. Accordingly, there is a possibility that diffusion of the post shielding gas is not sufficiently suppressed.

[0005] The present disclosure is made to solve the problem as described above, and an object of the present disclosure is to provide a welding apparatus in which diffusion of a post shielding gas is suppressed. SOLUTION TO PROBLEM

[0006] A post shielding gas jig according to the present disclosure includes a gas supply portion. The gas supply portion includes a discharge portion. The discharge portion enables a post shielding gas to blow from the discharge portion toward a workpiece. The gas supply portion includes a shielding portion and a first keeping mechanism portion. The shielding portion is disposed so as to surround the discharge portion as seen in a direction in which the post shielding gas blows. The first keeping mechanism portion enables a distance between the shielding portion and the workpiece to be kept constant independently of a position of a welding torch.

[0007] A welding apparatus according to the present disclosure includes the welding torch and the post shielding gas jig. A welding equipment according to the present disclosure includes the welding apparatus, a holding mechanism portion, and a rotation mechanism portion. The holding mechanism portion holds the workpiece. The rotation mechanism portion rotates the workpiece.

[0008] A welding method according to the present disclosure includes: moving the workpiece to a vicinity of the welding apparatus; and welding the workpiece. The moving includes moving the workpiece to bring the workpiece into contact with the first keeping mechanism portion. The welding includes causing the welding torch to generate an arc toward the workpiece. The welding includes causing the post shielding gas to be blown from the gas supply portion toward the workpiece. The welding includes, keeping constant, by the first keeping mechanism portion, the distance between the shielding portion and the workpiece. The welding includes, keeping constant, by the second keeping mechanism portion, the distance between the welding torch and the workpiece.

[0009] A welding method according to the present disclosure includes: moving the workpiece to a vicinity of the welding apparatus; and welding the workpiece. The moving includes moving the workpiece to bring the workpiece into contact with the first keeping mechanism portion. The welding includes causing the welding torch to generate an arc toward the workpiece. The welding includes causing the post shielding gas to be blown from the gas supply portion toward the workpiece. The welding includes, keeping constant, by the first keeping mechanism portion, the distance between the shielding portion and the workpiece. The welding includes, adjusting, by the drive unit, the distance between the welding torch and the workpiece.

[0010] A method of manufacturing a cylindrical structure according to the present disclosure is a method of manufacturing a cylindrical structure using the welding method as describe above. The workpiece includes a body portion and a pair of end portions that constitute the cylindrical structure. ADVANTAGEOUS EFFECTS OF INVENTION

[0011] According to the foregoing, it is possible to obtain a welding apparatus in which diffusion of the post shielding gas is suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0012] Fig. 1 is a perspective view of a welding apparatus according to Embodiment 1. Fig. 2 is a schematic cross-sectional view of a gas supply portion along line II-II in Fig. 1. Fig. 3 is a schematic cross-sectional view of the welding apparatus according to Embodiment 1. Fig. 4 is a schematic cross-sectional view showing a modification of the gas supply portion in the welding apparatus according to Embodiment 1. Fig. 5 is a schematic cross-sectional view showing a modification of the gas supply portion in the welding apparatus according to Embodiment 1. Fig. 6 is a schematic cross-sectional view showing a modification of the gas supply portion in the welding apparatus according to Embodiment 1. Fig. 7 is a schematic cross-sectional view showing a modification of the gas supply portion in the welding apparatus according to Embodiment 1. Fig. 8 is a side view showing a modification of a lateral side shielding portion in the welding apparatus according to Embodiment 1. Fig. 9 is a side view showing a modification of the lateral side shielding portion in the welding apparatus according to Embodiment 1. Fig. 10 is a side view showing a positional relationship between the lateral side shielding portion and a welding torch in the welding apparatus according to Embodiment 1. Fig. 11A is a side view showing a modification of a first keeping mechanism portion in the welding apparatus according to Embodiment 1. Fig. 1 IB is a side view showing a modification of the first keeping mechanism portion in the welding apparatus according to Embodiment 1. Fig. 1 IC is a front view showing a modification of the first keeping mechanism portion in the welding apparatus according to Embodiment 1. Fig. 1 ID is a side view showing a modification of the lateral side shielding portion in the welding apparatus according to Embodiment 1. Fig. 1 IE is a side view showing a modification of the lateral side shielding portion in the welding apparatus according to Embodiment 1. Fig. 12 is a schematic cross-sectional view showing a modification of a post shielding gas jig in the welding apparatus according to Embodiment 1. Fig. 13 is a perspective view showing a modification of the post shielding gas jig in the welding apparatus according to Embodiment 1. Fig. 14 is a cross-sectional perspective view showing a gas supply portion in a welding apparatus according to Embodiment 2. Fig. 15A is a cross-sectional perspective view showing a gas supply portion in a welding apparatus according to Embodiment 3. Fig. 15B is a cross-sectional perspective view showing a modification of the gas supply portion in the welding apparatus according to Embodiment 3. Fig. 16 is a cross-sectional perspective view showing the gas supply portion in the welding apparatus according to Embodiment 3. Fig. 17 is a perspective view of a welding apparatus according to Embodiment 4. Fig. 18 is a schematic diagram for illustrating a configuration in a modification of the welding apparatus according to Embodiment 4. Fig. 19 is a schematic diagram of a welding equipment according to Embodiment 5. DESCRIPTION OF EMBODIMENTS

[0013] Embodiments of the present disclosure are hereinafter described. In the following drawings, the same or corresponding parts are denoted by the same reference numerals unless otherwise specified, and a description thereof is not herein repeated.

[0014] Embodiment 1. <Configuration of Welding Apparatus> Fig. 1 is a perspective view of a welding apparatus 100 according to Embodiment 1. Fig. 2 is a schematic cross-sectional view of a gas supply portion 20 along line 11 -11 in Fig. 1. Fig. 3 is a schematic cross-sectional view of welding apparatus 100 according to Embodiment 1.

[0015] Welding apparatus 100 shown in Figs. 1 to 3 is a welding apparatus 100 that performs the so-called TIG (Tungsten Inert Gas) welding method, and is a part of items constituting a welding equipment 300 (see Fig. 19) as described later herein. Welding apparatus 100 mainly includes a welding torch 1, a drive unit 2, and a post 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 distance between welding torch 1 and a workpiece 200 (a molten pool of the workpiece) is kept constant. Post shielding gas jig 10 that moves together with welding torch 1 supplies a post shielding gas to thermally deformed workpiece 200 after welding. There is a method of making the relative positional relationship between welding torch 1 and workpiece 200 constant, by lowering, before each welding process, welding torch 1 at a low speed to bring an electrode portion la of welding torch 1 and workpiece 200 into contact with each other so that welding torch 1 and workpiece 200 are conductively connected, to check the distance between welding torch 1 and workpiece 200. In this case, in order to avoid contact between post shielding gas jig 10 and workpiece 200, it is necessary to increase the distance between post shielding gas jig 10 and workpiece 200 by a distance by which welding torch 1 is lowered.

[0017] As shown in Fig. 3, welding torch 1 includes electrode portion la. Electric power is supplied to electrode portion la to cause an arc to be generated between electrode portion la and workpiece 200. When workpiece 200 is welded, welding torch 1 is held by drive unit 2, and therefore, the absolute position of welding torch 1 may not be changed, and the distance between welding torch 1 and workpiece 200 may be adjusted based on the voltage of the arc.

[0018] The shape of electrode portion la is, for example, a rod shape along a central axis 1c as shown in Fig. 3. Central axis 1c of electrode portion la is an imaginary axis extending in the direction in which electrode portion la extends, and passing through the central portion in a cross section perpendicular to the direction in which electrode portion la extends, in the case where the shape of electrode portion la is a rod shape.

[0019] In the case where workpiece 200 is a cylindrical structure, welding torch 1 may be disposed such that central axis 1c is perpendicular to a tangent line to the cylindrical structure. The tangent line is a tangent line at a weld portion A. Weld portion A is a portion where the cylindrical structure is welded by welding torch 1.

[0020] Post shielding gas jig 10 includes gas supply portion 20, a pair of rails 30, and a first connecting portion 40. First connecting portion 40 is slidable on rails 30. First connecting portion 40 may hold welding torch 1. Specifically, first connecting portion 40 includes a sliding portion 41, a first block portion 42, a second block portion 43, and an arm portion 44.

[0021] Sliding portion 41 is connected to rail 30 and is slidable on rail 30. First block portion 42 is connected so as to be fixed to sliding portion 41. Second block portion 43 is connected so as to be fixed to first block portion 42. Arm portion 44 is connected so as to be fixed to second block portion 43. Arm portion 44 may hold welding torch 1.

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

[0023] Each of the pair of rails 30 has a stopper 31. Stopper 31 is disposed at the upper end of rail 30. In this way, sliding portion 41 is prevented from being detached from rail 30.

[0024] Gas supply portion 20 includes a discharge portion 21h, a shielding portion 21, and a filter 2If. The post shielding gas is blown from discharge portion 21h toward workpiece 200. Discharge portion 21h is a space formed by being surrounded by shielding portion 21. Filter 21 f is disposed in the space (discharge portion 21h).

[0025] Discharge portion 21h has a discharge surface 21s. As shown in Fig. 3, discharge surface 21s faces workpiece 200. The post shielding gas is blown from discharge surface 21s. The direction in which the post shielding gas is blown is perpendicular to discharge surface 21s. In Fig. 3, the direction in which the post shielding gas is blown is defined as Z direction. In Fig. 3, the X direction is defined as a direction in which welding torch 1 is located as seen from discharge portion 21h. The X direction is a direction perpendicular to the Z direction. A direction perpendicular to the X direction and the Z direction is defined as Y direction. As shown in Fig. 3, the Z direction is also a direction perpendicular to the tangent line to workpiece 200.

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

[0027] As shown in Fig. 1, the pair of lateral side shielding portions 21c are separated from each other in the Y direction. The pair of lateral side shielding portions 21c is disposed such that upper side shielding portion 21a is sandwiched therebetween.

[0028] As shown in Fig. 3, rear side shielding portion 21b is located at a position farthest from welding torch 1 in the X direction. Rear side shielding portion 21b is connected to upper side shielding portion 21a and the pair of lateral side shielding portions 21c. Thus, upper side shielding portion 21a, rear side shielding portion 21b, and the pair of lateral side shielding portions 21c are connected to each other to form discharge portion 21h. Upper side shielding portion 21a, rear side shielding portion 21b, and the pair of lateral side shielding portions 21c may be connected to each other by any method, and may be fastened to each other with screws, for example.

[0029] Shielding portion 21 is thus disposed so as to surround discharge portion 21h, to thereby prevent the post shielding gas from leaking out and diffusing from a gap between discharge surface 21s and workpiece 200. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere. In particular, discharge portion 21h is preferably surrounded along the four sides by shielding portion 21.

[0030] Argon gas, nitrogen gas, helium gas, carbon dioxide gas, or a gas mixture thereof, for example, can be used as a post shielding gas. The gas mixture may contain oxygen gas as an active gas.

[0031] A pipe joint 51 is connected to rear side shielding portion 21b. A through hole is formed in a side surface of rear side shielding portion 21b, and pipe joint 51 is attached to the through hole. A cable (not shown) branched from a centralized piping in a factory, for example, is connected to pipe joint 51 disposed in this manner. Pipe joint 51 allows the cable and discharge portion 21h to communicate with each other. The post shielding gas is supplied to discharge portion 21h through pipe joint 51. Pipe joint 51 may be connected to either upper side shielding portion 21a or lateral side shielding portion 21c.

[0032] The post shielding gas supplied to discharge portion 2Ih is blown toward workpiece 200 from discharge surface 21s through filter 2If. As shown in Fig. 2, in a side view of gas supply portion 20, filter 21f is disposed between discharge surface 21s and pipe joint 51 in the Z direction. The shape of filter 2 If is, for example, a mesh shape. Thus, the flow of the post shielding gas is regulated by being passed through filter 2If. That is, the post shielding gas is prevented from locally blowing to workpiece 200, and is therefore blown to workpiece 200 in a wide range.

[0033] Filter 21f may be fixed in discharge portion 21h in any manner. For example, a groove may be formed in each of protruding portion 21g of upper side shielding portion 21a, rear side shielding portion 21b, and the pair of lateral side shielding portions 21c. The outer peripheral portion of filter 21 f is fit in the grooves, so that filter 21 f is held in discharge portion 21h.

[0034] Gas supply portion 20 may include a plurality of filters 2 If. Specifically, the number of filters 21f may be one, but the number of filters 21 f may be two or three or more as shown in Fig. 2, for example. A plurality of filters 21 f may be separated from each other in the Z direction. Thus, a plurality of filters 21 f are provided to further regulate the flow of the post shielding gas, so that the post shielding gas blows to workpiece 200 in a wider range.

[0035] The shape of filter 21f may be a mesh shape, and the material forming filter 21 f may be, for example, a metal mesh. The material forming filter 21 f may be perforated metal, steel wool, or a combination thereof, besides the metal mesh. Filter 21 f may be a porous body made of ceramic or metal.

[0036] Post shielding gas jig 10 according to Embodiment 1 is characterized in that gas supply portion 20 enables the distance between shielding portion 21 and workpiece 200 to be adjusted independently of the position of welding torch 1. Specifically, gas supply portion 20 includes a first keeping mechanism portion 22 as a keeping mechanism portion. First keeping mechanism portion 22 includes a ball roller 22a and a bracket 22b.

[0037] As shown in Fig. 1, bracket 22b may have an L-shaped side surface, for example. Specifically, bracket 22b has a first surface and a second surface. The first surface is a surface perpendicular to the second surface.

[0038] Bracket 22b may only need to be connected to gas supply portion 20 and, in Embodiment 1, the first surface of bracket 22b is connected to lateral side shielding portion 21c. Bracket 22b may only need to be fixed to lateral side shielding portion 21c by any method, and may be connected with a screw(s), for example.

[0039] Ball roller 22a is connected to bracket 22b. Specifically, ball roller 22a is connected to, for example, a columnar part. A through hole may be formed in the second surface of bracket 22b. External threads may be formed in the side surface of the columnar part, and internal threads may be formed in the inner peripheral surface of the through hole. That is, the columnar part may be inserted into the through hole of bracket 22b, and the columnar part may be fixed to bracket 22b so as to sandwich the second surface with nuts. Ball roller 22a is disposed at the distal end of the columnar part. Ball roller 22a can roll on the surface of workpiece 200.

[0040] First keeping mechanism portion 22 may be connected to at least one of the pair of lateral side shielding portions 21c. Two first keeping mechanism portions 22 may be provided. In this case, first keeping mechanism portions 22 may be connected respectively to the pair of lateral side shielding portions 21c.

[0041] As shown in Fig. 1, first keeping mechanism portion 22 may be connected to one lateral side shielding portion 21c. It is supposed that workpiece 200 is made up of two separate members. When the two separate members are to be connected together by welding, for example, and one of the two separate members has an uneven surface or an inclined surface, for example, it is difficult to adjust the distance between post shielding gas jig 10 and workpiece 200, even if the two first keeping mechanism portions 22 are brought into contact with workpiece 200. In such a case, it is not necessary to provide two first keeping mechanism portions 22, and first keeping mechanism portion 22 may be connected to one of lateral side shielding portions 21c, depending on workpiece 200.

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

[0043] When workpiece 200 is welded, welding torch 1 is disposed at any 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. That is, 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 vary.

[0044] As described later herein, welding apparatus 100 may include a processing circuit 3 (see Fig. 18). Processing circuit 3 detects the voltage of an arc generated from electrode portion la of welding torch 1. Drive unit 2 may adjust the distance between welding torch 1 and workpiece 200 based on the detected voltage of the arc.

[0045] When workpiece 200 is welded, post shielding gas jig 10 is supported by ball roller 22a against workpiece 200. That is, the relative position of shielding portion 21 with respect to workpiece 200 is determined by first keeping mechanism portion 22.

[0046] When workpiece 200 is a cylindrical structure, workpiece 200 may be eccentric or workpiece 200 may not have the shape of a perfect circle. In these cases, as workpiece 200 rotates, respective relative positions of welding torch 1 and shielding portion 21 with respect to workpiece 200 change.

[0047] When the relative position of shielding portion 21 with respect to workpiece 200 changes, there is a possibility that the post shielding gas may diffuse from a gap between shielding portion 21 and workpiece 200. Accordingly, weld portion A of workpiece 200 cannot be sufficiently shielded from the atmosphere by the post shielding gas.

[0048] In post shielding gas jig 10 according to Embodiment 1, ball roller 22a rolls on the surface of workpiece 200 when workpiece 200 is rotating. Therefore, even when workpiece 200 is eccentric or workpiece 200 does not have the shape of a perfect circle, the relative position of shielding portion 21 with respect to workpiece 200 does not change. That is, the distance between shielding portion 21 and workpiece 200 is kept constant by first keeping mechanism portion 22.

[0049] Rails 30 are connected to gas supply portion 20. Therefore, as the absolute position of gas supply portion 20 changes, the absolute position of rails 30 also changes. Since the absolute position of welding torch 1 is adjusted by drive unit 2, first connecting portion 40 slides on rails 30. That is, the distance between shielding portion 21 and workpiece 200 is kept constant independently of the position of welding torch 1. In this way, the relative position of shielding portion 21 with respect to workpiece 200 is appropriately set, such that diffusion of the post shielding gas from a gap between discharge surface 21s and workpiece 200 is further suppressed. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere. Thus, oxidation of weld portion A can be suppressed.

[0050] Welding torch 1 may not be held by drive unit 2. For example, welding torch 1 may be held by first connecting portion 40. First connecting portion 40 may be held by drive unit 2.

[0051] Fig. 4 is a schematic cross-sectional view showing a modification of gas supply portion 20 in welding apparatus 100 according to Embodiment 1. Fig. 4 corresponds to Fig. 2. Welding apparatus 100 shown in Fig. 4 basically has a similar configuration to that of welding apparatus 100 shown in Figs. 1 to 3, but differs therefrom in terms of the structure of upper side shielding portion 21a. Specifically, upper side shielding portion 21a includes a curved surface portion 21r. Curved surface portion 21r is formed at a comer of protruding portion 21 g, in the inner peripheral surface of upper side shielding portion 21a.

[0052] Thus, the post shielding gas supplied from pipe joint 51 does not stay in the comer in discharge portion 21h but flows downward.

[0053] Figs. 5 to 7 are schematic cross-sectional views each showing a modification of gas supply portion 20 in welding apparatus 100 according to Embodiment 1. Each of Figs. 5 to 7 corresponds to Fig. 2. Welding apparatuses 100 shown in Figs. 5 to 7 basically have a similar configuration to that of welding apparatus 100 shown in Figs. 1 to 3, but differ therefrom in that gas supply portion 20 includes a diffusion plate(s) 52.

[0054] Diffusion plate 52 is disposed in discharge portion 21 h. Diffusion plate 52 prevents the post shielding gas supplied from pipe joint 51 from becoming a turbulent flow. That is, diffusion plate 52 causes the post shielding gas to flow downward in the form of a laminar flow.

[0055] Diffusion plate 52 may be fixed in discharge portion 21h by any method. For example, a groove may be formed in each of the pair of lateral side shielding portions 21c. The outer peripheral portion of diffusion plate 52 is fit in the grooves, so that diffusion plate 52 is held in discharge portion 21h.

[0056] The material forming diffusion plate 52 is not particularly limited, but may be, for example, any of iron, stainless steel, copper, aluminum, and ceramic.

[0057] The shape, the position, and the quantity of diffusion plate(s) 52 are not particularly limited. As shown in Fig. 5, diffusion plate 52 may be disposed in a direction perpendicular to the X direction. Thus, the post shielding gas supplied from pipe joint 51 is blown to workpiece 200 via diffusion plate 52.

[0058] Diffusion plate 52 may not be disposed in the direction perpendicular to the X direction. Diffusion plate 52 may be disposed so as to be inclined with respect to the X direction as shown in Fig. 6, for example.

[0059] While the number of diffusion plates 52 may be one, a plurality of diffusion plates 52 may be disposed in discharge portion 21h. As shown in Fig. 7, the number of diffusion plates 52 may be, for example, two. Two diffusion plates 52 may be arranged in the X direction.

[0060] Lateral side shielding portion 21c has an upper surface, a front surface 25s2, a rear surface 25s 1, and a lower surface 25. The upper surface is a surface opposite to lower surface 25. Lower surface 25 faces workpiece 200. That is, the upper surface and lower surface 25 are opposite end surfaces in the Z direction. Front surface 25s2 is a surface opposite to rear surface 25sl. Rear surface 25sl is a surface farthest from welding torch 1 in the X direction. That is, front surface 25s2 and rear surface 25sl are opposite end surfaces in the X direction.

[0061] While the shape of lateral side shielding portion 21c may be any shape, the shape of lower surface 25 is preferably a shape extending along the surface of workpiece 200. As shown in Fig. 3, lower surface 25 may include a pair of horizontal portions 25a and an inclined portion 25b. In the X direction, inclined portion 25b is disposed so as to be located between the pair of horizontal portions 25 a. The pair of horizontal portions 25a are disposed apart from each other in the Z direction. The pair of horizontal portions 25 a is connected through inclined portion 25b. Inclined portion 25b extends in the direction along the surface of workpiece 200. In this way, the gap between shielding portion 21 and workpiece 200 can be reduced. As a result, diffusion of the post shielding gas from the gap between shielding portion 21 and workpiece 200 is suppressed. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere.

[0062] Figs. 8 and 9 are side views each showing a modification of lateral side shielding portion 21c in welding apparatus 100 according to Embodiment 1. Welding apparatuses 100 shown in Figs. 8 and 9 basically have a similar configuration to that of welding apparatus 100 shown in Figs. 1 to 3, but differ therefrom in terms of the shape of lateral side shielding portion 21c.

[0063] The shape of lower surface 25 may only need to be a shape extending along the surface of workpiece 200. Therefore, as shown in Fig. 8, the shape of lower surface 25 may be a shape of a combination of a plurality of linear portions 25c, for example. The plurality of linear portions 25c are disposed so as to be located between the pair of horizontal portions 25 a. For example, as shown in Fig. 9, lower surface 25 may have a curved surface portion 25d. Curved surface portion 25d is disposed so as to be located between the pair of horizontal portions 25 a.

[0064] In this way, the gap between shielding portion 21 and workpiece 200 can be further reduced. As a result, diffusion of the post shielding gas from the gap between shielding portion 21 and workpiece 200 is suppressed. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere.

[0065] While welding torch 1 may be disposed at any position, the welding torch is preferably disposed so as to be located between the pair of lateral side shielding portions 21c in the Y direction. Specifically, as shown in Fig. 3, in a side view of welding apparatus 100, welding torch 1 and electrode portion la preferably overlap lateral side shielding portion 21c in the X direction. From a different point of view, welding torch 1 is preferably disposed between front surface 25s2 and rear surface 25si of lateral side shielding portion 21c in the X direction. Thus, the post shielding gas whose diffusion in the Y direction is suppressed by lateral side shielding portions 21c impinges on weld portion A. Accordingly, oxidation of weld portion A is further suppressed.

[0066] Fig. 10 is a side view showing a positional relationship between lateral side shielding portion 21c and welding torch 1 in welding apparatus 100 according to Embodiment 1. As shown in Fig. 10, in the side view of welding apparatus 100, a part of welding torch 1 may not overlap lateral side shielding portion 21c. Alternatively, in the side view of welding apparatus 100, the whole of welding torch 1 may not overlap lateral side shielding portion 21c. Specifically, in the X direction, welding torch 1 may be located away in the X direction from front surface 25s2 of lateral side shielding portion 21c, as seen from rear surface 25si of lateral side shielding portion 21c. Thus, the positional relationship between electrode portion la and workpiece 200 can be easily confirmed visually, since electrode portion la of welding torch 1 is not covered with lateral side shielding portion 21c.

[0067] Fig. 11A is a side view showing a modification of first keeping mechanism portion 22 in welding apparatus 100 according to Embodiment 1. Welding apparatus 100 shown in Fig. 11A basically has a similar configuration to that of welding apparatus 100 shown in Figs. 1 to 3, but differs therefrom in terms of the structure of first keeping mechanism portion 22. First keeping mechanism portion 22 may have any structure. As shown in Fig. 11 A, first keeping mechanism portion 22 is made up of a shaft portion 22c and a rotatable roller 22d. Shaft portion 22c connects first keeping mechanism portion 22 and lateral side shielding portion 21c. Shaft portion 22c extends in the direction along the Y direction. Rotatable roller 22d rotates about shaft portion 22c. Along with rotation of workpiece 200, rotatable roller 22d is capable of rolling on the surface of workpiece 200.

[0068] As described above, lateral side shielding portion 21c has rear surface 25sl and front surface 25s2. At rear surface 25s 1, lateral side shielding portion 21c is connected to rear side shielding portion 21b. Front surface 25s2 is located opposite to rear surface 25s 1 in the X direction.

[0069] First keeping mechanism portion 22 including shaft portion 22c and rotatable roller 22d may be disposed such that influences of heat generated by welding are reduced. Specifically, the central axis of shaft portion 22c may be located in a region QI in the X direction. Region QI is a region from rear surface 25sl to 50% of a width L in the X direction. Width L may be the distance from rear surface 25s 1 to front surface 25s2 in the X direction. Region QI may be a region from rear surface 25si to central axis 1c of welding torch 1. Thus, rotatable roller 22d is disposed near the rail 30, and therefore, rotatable roller 22d can more easily roll on the surface of workpiece 200.

[0070] In the case where workpiece 200 is made up of two members (for example, a body portion 201 or an end portion 202 shown in Fig. 19), if both of or one of these members has a distorted shape, the distance between shielding portion 21 and workpiece 200 cannot be sufficiently adjusted by rotatable roller 22d. Therefore, first keeping mechanism portion 22 may be connected to each of the pair of lateral side shielding portions 21c so that rotatable roller 22d can contact either of these members.

[0071] Fig. 1 IB is a side view showing a modification of first keeping mechanism portion 22 in welding apparatus 100 according to Embodiment 1. Fig. 1 IB corresponds to Fig. 11A. First keeping mechanism portion 22 shown in Fig. 1 IB basically has a similar configuration to that of first keeping mechanism portion 22 shown in Fig. 11A, but differs therefrom in that a position adjusting portion 23 is provided between lateral side shielding portion 21c and first keeping mechanism portion 22.

[0072] Position adjusting portion 23 may be, for example, a plate member as shown in Fig-1 IB. The plate member is provided with a plurality of through holes hl, h2, and h3. A screw is inserted through the through hole hl, h2, h3. That is, a screw is inserted through any of through holes hl, h2, and h3, to thereby fix first keeping mechanism portion 22 to the plate member through the screw.

[0073] Through holes hl and h2 may be, for example, drilled holes formed with a drill. As shown in Fig. 1 IB, the shape of the openings of through holes hl and h2 (the shape of through holes hl and h2 as seen in the Y direction) may be circular or elliptical.

[0074] Through hole hl is located apart from through hole h2 in the X direction. The position in the X direction where first keeping mechanism portion 22 is fixed may be adjusted by inserting a screw through any of through holes hl and h2. The relative position of first keeping mechanism portion 22 with respect to lateral side shielding portion 21c may be changed in this way.

[0075] As shown in Fig. 1 IB, the opening of through hole h3 may extend in the Z direction. Specifically, the dimension of through hole h3 in the Z direction may be larger than the dimension thereof in the X direction. Thus, through hole h3 may be an elongated hole extending in the Z direction. The position in the Z direction where first keeping mechanism portion 22 is fixed may be adjusted by inserting a screw, at any position in the Z direction, through the through hole h3. The relative position of first keeping mechanism portion 22 with respect to lateral side shielding portion 21c may be changed in this way.

[0076] The opening of through hole h3 may extend in the X direction. Specifically, the dimension of through hole h3 in the X direction may be larger than the dimension thereof in the Z direction. Thus, through hole h3 may be an elongated hole extending in the X direction.

[0077] Fig. 1 IC is a front view showing a modification of first keeping mechanism portion 22 in welding apparatus 100 according to Embodiment 1. First keeping mechanism portion 22 shown in Fig. 1 IC basically has a similar configuration to that of first keeping mechanism portion 22 shown in Figs. 1 to 3, but differs therefrom in that first keeping mechanism portion 22 has an adjuster bolt mechanism. First keeping mechanism portion 22 is shown in Fig. 1 IC in a front view as seen in the X direction.

[0078] As shown in Fig. 1 IC, ball roller 22a is connected to, for example, a columnar part 22f. A through hole may be formed in a second surface 22b2 of bracket 22b. External threads may be formed in the side surface of columnar part 22f, and internal threads may be formed in the inner peripheral surface of the through hole. Columnar part 22f is inserted in the through hole of bracket 22b. Columnar part 22f is movable in the direction perpendicular to second surface 22b2 (for example, the direction along the Z direction). Columnar part 22f is fixed to bracket 22b with a nut. The relative position of ball roller 22a in first keeping mechanism portion 22, with respect to lateral side shielding portion 21c, may be changed in this way. In the case where formation of a scratch or the like in workpiece 200 such as body portion 201 or end portion 202 shown in Fig. 19 is acceptable, ball roller 22a or rotatable roller 22d shown in Figs. 11A to 11C may not be used. In this case, the distance between shielding portion 21 and workpiece 200 may be adjusted by directly bringing lateral side shielding portion 21c or bracket 22b into contact with workpiece 200.

[0079] Fig. 1 ID is a side view showing a modification of lateral side shielding portion 21c in welding apparatus 100 according to Embodiment 1. Lateral side shielding portion 21c shown in Fig. 1 ID basically has a similar configuration to that of lateral side shielding portion 21c shown in Figs. 1 to 3, but differs therefrom in that lateral side shielding portion 21c is provided with a link member 23g.

[0080] Link member 23g may be a plate-shaped member. One side that forms link member 23g conforms to the shape of workpiece 200. A part of one side that forms link member 23g may be in contact with workpiece 200.

[0081] Link member 23g is connected to lateral side shielding portion 21c through a shaft portion 23gl. Link member 23g is provided with shaft portion 23gl. As shown in Fig. 1 ID, shaft portion 23gl is disposed near the distal end of welding torch 1. Link member 23 g and lateral side shielding portion 21c are connected to each other by shaft portion 23g 1. Shaft portion 23gl extends in the direction along the Y direction. Link member 23g rotates about shaft portion 23gl serving as a central axis.

[0082] Link member 23g is provided with a through hole h4. The opening of through hole h4 extends along the rotational direction of link member 23g. A fixing member 23g2 is inserted through the through hole h4. The relative position of link member 23 g with respect to lateral side shielding portion 21c may be fixed by fixing member 23g2.

[0083] First keeping mechanism portion 22 is disposed near rear surface 25s 1 in the X direction. In this way, diffusion of the post shielding gas from a gap between shielding portion 21 and workpiece 200 is further suppressed by link member 23g. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere without using rails 30.

[0084] Fig. 1 IE is a side view showing a modification of lateral side shielding portion 21c in welding apparatus 100 according to Embodiment 1. Lateral side shielding portion 21c shown in Fig. 1 IE basically has a similar configuration to that of lateral side shielding portion 21c shown in Figs. 1 to 3, but differs therefrom in that lateral side shielding portion 21c includes a movable portion 8.

[0085] Specifically, lateral side shielding portion 21c includes a main body portion 81 and a movable portion 82. Main body portion 81 is connected to rear side shielding portion 21b. First keeping mechanism portion 22 is connected to main body portion 81.

[0086] Movable portion 82 is connected to main body portion 81 through a coupling portion 84. Movable portion 82 is disposed opposite to rear surface 25s 1 in the X direction. Movable portion 8 is formed by a plurality of linked members 83. The plurality of linked members 83 are connected to each other through coupling portions 84.

[0087] Each of the plurality of linked members 83 is slidable, for example, in the X direction and the Z direction. Specifically, linked member 83 is provided with a fit portion in which coupling portion 84 is fit. The fit portion may be, for example, a through hole extending in the X direction. The position of linked member 83 in the X direction is determined by the position at which coupling portion 84 is fit in the fit portion. Linked member 83 may rotate about coupling portion 84. Thus, linked member 83 is slidable in the X direction and the Y direction with respect to adjacent linked member 83. Therefore, as shown in Fig. 1 IE, the plurality of linked members 83 can be arranged such that respective lower ends of the plurality of linked members 83 conform to the shape of workpiece 200 (for example, body portion 201 or end portions 202 shown in Fig. 19).

[0088] In this way, diffusion of the post shielding gas from a gap between shielding portion 21 and workpiece 200 is further suppressed. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere.

[0089] Fig. 12 is a schematic cross-sectional view showing a modification of post shielding gas jig 10 in welding apparatus 100 according to Embodiment 1. Fig. 12 corresponds to Fig. 3. Welding apparatus 100 shown in Fig. 12 basically has a similar configuration to that of welding apparatus 100 shown in Figs. 1 to 3 but differs therefrom in that post shielding gas jig 10 includes a flame-retardant cover 24. As shown in Fig. 12, cover 24 is connected to gas supply portion 20. Cover 24 may be a pair of covers. The pair of covers 24 is disposed outside shielding portion 21 in the Y direction. Specifically, the pair of covers 24 may be disposed so as to sandwich the pair of lateral side shielding portions 21c in the Y direction.

[0090] When workpiece 200 is welded so as not to cause the post shielding gas to leak from a gap between shielding portion 21 and workpiece 200, cover 24 is preferably disposed in the vicinity of workpiece 200. In particular, as shown in Fig. 12, cover 24 may be in contact with workpiece 200. Therefore, cover 24 may have cuts formed at any positions so that the shape of the cover conforms to the surface of workpiece 200.

[0091] Thus, diffusion of the post shielding gas from a gap between shielding portion 21 and workpiece 200 is further suppressed. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere.

[0092] When workpiece 200 is welded, the temperature of workpiece 200 may reach a high temperature due to heat generated by the welding. Therefore, preferably cover 24 is flame-retardant. In particular, the material forming cover 24 is preferably, for example, any of glass fiber, ceramic-based fiber, and carbon fiber.

[0093] When cover 24 is in contact with workpiece 200, deterioration of cover 24 is accelerated by wear and heat due to welding. Therefore, when workpiece 200 is welded, cover 24 may not be in contact with workpiece 200.

[0094] Fig. 13 is a perspective view showing a modification of post shielding gas jig 10 in welding apparatus 100 according to Embodiment 1. Fig. 13 corresponds to Fig. 1. Welding apparatus 100 shown in Fig. 13 basically has a similar configuration to that of welding apparatus 100 shown in Figs. 1 to 3 but differs therefrom in that shielding portion 21 includes a front side shielding portion 2Id. Specifically, front side shielding portion 21 d is connected to the front surfaces of the pair of lateral side shielding portions 21c. Welding torch 1 is disposed between protruding portion 21g of upper side shielding portion 21a and front side shielding portion 21 d in the X direction. Thus, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere.

[0095] The material forming post shielding gas jig 10 may be, for example, any of iron, stainless steel, copper, aluminum, and ceramic. A plurality of post shielding gas jigs 10 may be provided in welding apparatus 100.

[0096] <Functions and Effects> Post shielding gas jig 10 according to the present disclosure includes gas supply portion 20. Gas supply portion 20 includes discharge portion 21h. A post shielding gas is enabled to blow from discharge portion 21h toward workpiece 200. Gas supply portion 20 includes shielding portion 21 and first keeping mechanism portion 22. Shielding portion 21 is disposed to surround discharge portion 21h as seen in the direction in which the post shielding gas blows. First keeping mechanism portion 22 enables a distance between shielding portion 21 and workpiece 200 to be kept constant independently of the position of welding torch 1.

[0097] In this way, the distance between shielding portion 21 and workpiece 200 is kept constant independently of the position of welding torch 1. Therefore, diffusion of the post shielding gas from a gap between shielding portion 21 and workpiece 200 is suppressed. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere.

[0098] Post shielding gas jig 10 includes rail 30 and first connecting portion 40. Rail 30 is connected to gas supply portion 20. First connecting portion 40 is slidable on rail 30. First connecting portion 40 is capable of holding welding torch 1. Thus, first keeping mechanism portion 22 enables the distance between shielding portion 21 and workpiece 200 to be kept constant regardless of the position of welding torch 1.

[0099] Post shielding gas jig 10 includes cover 24. Cover 24 is connected to gas supply portion 20. Cover 24 is flame-retardant. Thus, when workpiece 200 is welded, cover 24 can be disposed in the vicinity of workpiece 200. That is, diffusion of the post shielding gas from a gap between shielding portion 21 and workpiece 200 is suppressed. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere.

[0100] In post shielding gas jig 10, the material forming cover 24 includes any of glass fiber, ceramic-based fiber, and carbon fiber. Thus, when workpiece 200 is welded, cover 24 can be disposed in the vicinity of workpiece 200. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere.

[0101] Welding apparatus 100 according to the present disclosure includes welding torch 1 and post shielding gas jig 10. Thus, the distance between shielding portion 21 and workpiece 200 is kept constant independently of the position of welding torch 1. Therefore, diffusion of the post shielding gas from a gap between shielding portion 21 and workpiece 200 is suppressed. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere.

[0102] Embodiment 2. <Configuration of Welding Apparatus> Fig. 14 is a cross-sectional perspective view showing gas supply portion 20 in welding apparatus 100 according to Embodiment 2. Welding apparatus 100 shown in Fig. 14 basically has a similar configuration to that of welding apparatus 100 shown in Figs. 1 to 3, but differs therefrom in terms of the structure of gas supply portion 20. Specifically, the shape of upper side shielding portion 21a is not an L shape, but a flat plate shape as shown in Fig. 14. Unlike upper side shielding portion 21a shown in Fig. 2, protruding portion 21g is not formed in upper side shielding portion 21a according to Embodiment 2.

[0103] A groove is formed in each of upper side shielding portion 21a, rear side shielding portion 21b, and the pair of lateral side shielding portions 21c. As shown in Fig. 14, filter 21 f is held in discharge portion 2Ih such that the outer peripheral portion of filter 21 f is fit in the groove of each of upper side shielding portion 21a, rear side shielding portion 21b, and the pair of lateral side shielding portions 21c. Therefore, in a side view of filter 2 If, the shape of filter 21 f has a curved portion as shown in Fig. 14.

[0104] Thus, the post shielding gas supplied from pipe joint 51 is enabled to blow in a direction perpendicular to a tangent line to workpiece 200 and a direction along the tangent line. The direction along the tangent line refers to the direction parallel to the tangent line and a direction inclined at an inclination angle of 30° or less with respect to the tangent line. Specifically, the post shielding gas blows in the direction along the X direction and the direction along the Z direction through filter 2 If. Asa result, welding apparatus 100 according to Embodiment 2 can blow the post shielding gas toward a wider range of workpiece 200 than welding apparatus 100 according to Embodiment 1.

[0105] <Functions and Effects> In post shielding gas jig 10, the post shielding gas is enabled to blow in a direction perpendicular to a tangent line to workpiece 200 and in a direction along the tangent line. Thus, the post shielding gas can be supplied to a wide range of workpiece 200. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere.

[0106] Embodiments. Configuration of Welding Apparatus> Figs. 15A and 16 are cross-sectional perspective views showing gas supply portion 20 in welding apparatus 100 according to Embodiment 3. Figs. 15A and 16 correspond to Fig. 14. Welding apparatus 100 shown in Figs. 15A and 16 basically has a configuration similar to that of welding apparatus 100 shown in Fig. 14, but differs therefrom in that welding torch 1 is disposed in an inclined posture with respect to workpiece 200. Specifically, as shown in Fig. 15A, an inclined portion 26 is formed in the upper surface of upper side shielding portion 21a. Inclined portion 26 is disposed at a corner portion of upper side shielding portion 21a, close to welding torch 1. Inclined portion 26 is a surface on which welding torch 1 is mounted.

[0107] As shown in Fig. 16, welding torch 1 is disposed on inclined portion 26. Arm portion 44 (not shown) is disposed so as to be able to hold welding torch 1 which is inclined. Accordingly, the position of weld portion A is further. However, in a side view of filter 21 f, the shape of filter 21 f has a curved portion. Therefore, the post shielding gas supplied from pipe joint 51 is blown in a direction perpendicular to the tangent line to workpiece 200 and in a direction along the tangent line. As a result, the post shielding gas can sufficiently shield weld portion A of workpiece 200 from the atmosphere.

[0108] Welding torch 1 is inclined with respect to workpiece 200. From a different point of view, central axis 1c of electrode portion la is inclined with respect to the tangent line to workpiece 200. Thus, a pressure due to an arc applied to weld portion A is dispersed not only in the direction perpendicular to the tangent line to workpiece 200 (Z direction) but also in the direction parallel to the tangent line (X direction). As a result, the pressure in the Z direction applied to weld portion A is reduced, and weld portion A is prevented from melting to drop in the form of a molten pool.

[0109] Gas supply portion 20 shown in Figs. 15A and 16 may include diffusion plate(s) 52 shown in Figs. 5 to 7 (not shown).

[0110] Rails 30 may be inclined along central axis 1c of welding torch 1 (not shown). From a different point of view, rails 30 may extend along central axis 1c of welding torch 1. Thus, welding torch 1 and gas supply portion 20 can move along central axis 1c of welding torch 1, independently of each other.

[0111] In the case where welding torch 1 is disposed in an inclined posture, a part of welding torch 1 may not overlap lateral side shielding portion 21c or the whole of welding torch 1 may not overlap lateral side shielding portion 21 c in a side view of welding apparatus 100, as described above with reference to Fig. 10.

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

[0113] Fig. 15B is a cross-sectional perspective view showing a modification of gas supply portion 20 in welding apparatus 100 according to Embodiment 3. Fig. 15B corresponds to Fig. 15 A. Gas supply portion 20 shown in Fig. 15B basically has a similar configuration to that of gas supply portion 20 shown in Fig. 15 A, but differs therefrom in that inclined portion 26 is formed by a curved surface. Specifically, inclined portion 26 is shaped to be recessed in the direction away from welding torch 1.

[0114] As shown in Fig. 16, welding torch 1 is cylindrical. From a different point of view, the shape of the outer periphery of welding torch 1 is circular. Thus, in the case where the shape of the outer periphery of welding torch 1 is circular, the gap formed between inclined portion 26 and welding torch 1 is smaller. As a result, diffusion of the post shielding gas from the gap is suppressed. In addition, the atmosphere is prevented from flowing from the gap to weld portion A.

[0115] As shown in Fig. 15B, gas supply portion 20 may include diffusion plate(s) 52 as shown in Figs. 5 to 7.

[0116] <Functions and Effects> In welding apparatus 100 as described above, welding torch 1 includes electrode portion la. Central axis 1c of electrode portion la is inclined with respect to a tangent line to workpiece 200. Thus, a pressure due to an arc applied to weld portion A is reduced. As a result, weld portion A is prevented from melting to drop in the form of a molten pool.

[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 a similar configuration to that of welding apparatus 100 shown in Fig. 1, but differs therefrom in that the distance between welding torch 1 and workpiece 200 is adjusted by a keeping mechanism portion, independently of the position of shielding portion 21. Specifically, welding apparatus 100 includes a second connecting portion 40y and a pair of rails 30y. Second connecting portion 40y is connected to welding torch 1. As shown in Fig. 17, the second connecting portion basically has a similar configuration to that of a first connecting portion 40x. Second connecting portion 40y may hold welding torch 1. Second connecting 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] Sliding portion 41y is connected to rail 30y and is slidable on rail 30y. First block portion 42y is connected so as to be fixed to sliding portion 41y. Second block portion 43y is connected so as to be fixed to first block portion 42y. Arm portion 44y is connected so as to be fixed to second block portion 43y. Arm portion 44y may hold welding torch 1.

[0119] Third block portion 45y is connected so as to be fixed to arm portion 44y. As shown in Fig. 17, third block portion 45y has a rectangular shape as seen in a side view of welding apparatus 100. Third block portion 45y extends in the Z direction.

[0120] Rails 30y are connected to be fixed to drive unit 2. A pair of rails 30y each have a stopper 3 ly. Stopper 3 ly is disposed at the upper end of rail 30y. In this way, sliding portion 4ly is prevented from being detached from rail 30y.

[0121] Second connecting portion 40y includes a second keeping mechanism portion 22y as a keeping mechanism portion. Second keeping mechanism portion 22y has a similar configuration to that of first keeping mechanism portion 22x, but differs therefrom in that second keeping mechanism portion 22y is connected so as to be fixed to third block portion 45y. Second keeping mechanism portion 22y keeps constant the distance between welding torch 1 and workpiece 200.

[0122] In this way, the distance between welding torch 1 and workpiece 200 is kept constant by second keeping mechanism portion 22y. Meanwhile, the distance between shielding portion 21 and workpiece 200 is kept constant by first keeping mechanism portion 22x. That is, the relative position of shielding portion 21 and the relative position of welding torch 1, with respect to workpiece 200, are determined independently of each other. As a result, in the case where workpiece 200 is displaced due to eccentricity or the like, respective relative positions of welding torch 1 and shielding portion 21 with respect to workpiece 200 remain the same and are kept constant even if workpiece 200 rotates.

[0123] <Functions and Effects> Welding apparatus 100 as described above includes second connecting portion 40y. Second connecting portion 40y is connected to welding torch 1. Second connecting portion 40y includes second keeping mechanism portion 22y. Second keeping mechanism portion 22y may keep constant the distance between welding torch 1 and workpiece 200. Thus, the distance between welding torch 1 and workpiece 200 is kept constant by second keeping mechanism portion 22y. That is, the respective relative positions of shielding portion 21 and welding torch 1 with respect to workpiece 200 are determined independently of each other. As a result, in the case where workpiece 200 is displaced due to eccentricity or the like, the respective relative positions of welding torch 1 and shielding portion 21 with respect to workpiece 200 remain the same and are kept constant even if workpiece 200 rotates.

[0124] <Configuration of Modification> Fig. 18 is a schematic diagram for explaining a configuration in a modification of welding apparatus 100 according to Embodiment 4. Welding apparatus 100 shown in Fig. 18 basically has a similar configuration to that of welding apparatus 100 shown in Fig. 17, but differs therefrom in that the distance between welding torch 1 and workpiece 200 is adjusted based on the voltage of an arc generated from electrode portion la of welding torch 1. Specifically, welding apparatus 100 includes processing circuit 3. As shown in Fig. 18, processing circuit 3 includes a control unit 3 a and a detection unit 3b.

[0125] Detection unit 3b is connected to control unit 3 a. Detection unit 3b detects the voltage of an arc generated from electrode portion la of welding torch 1. A voltage sensor that measures the voltage of the arc can be used as detection unit 3b. When workpiece 200 is displaced due to eccentricity or the like, the distance (arc length) between workpiece 200 and welding torch 1 changes, and as a result, the voltage of the arc changes.

[0126] Control unit 3 a controls drive unit 2 based on the voltage of the arc detected by detection unit 3b. Specifically, control unit 3a controls drive unit 2 such that the voltage of the arc approaches a preset voltage. As a result, drive unit 2 can change the position of welding torch 1 with respect to workpiece 200. Thus, the position of welding torch 1, i.e., the position of electrode portion la can 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 portion la, independently of the position of shielding portion 21. That is, the respective relative positions of shielding portion 21 and welding torch 1 with respect to workpiece 200 are detennined independently of each other. As a result, in the case where workpiece 200 is displaced due to eccentricity or the like, the respective relative positions of welding torch 1 and shielding portion 21 with respect to workpiece 200 remain the same, and are kept constant or adjusted to be constant, even if workpiece 200 rotates.

[0128] <Functions and Effects> Welding apparatus 100 as described above includes drive unit 2 and processing circuit 3. Drive unit 2 is connected to welding torch 1. Processing circuit 3 detects the voltage of an arc generated from electrode portion la of welding torch 1. Drive unit 2 adjusts the distance between welding torch 1 and 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 portion la, independently of the position of shielding portion 21. That is, the respective relative positions of shielding portion 21 and welding torch 1 with respect to workpiece 200 are determined independently of each other.

[0130] Embodiments. <Configuration of Welding Equipment Fig. 19 is a schematic diagram of welding equipment 300 according to Embodiment 5. Welding equipment 300 shown in Fig. 19 is a welding equipment 300 for welding workpiece 200 that is a cylindrical structure. The cylindrical structure is, for example, a hot water storage tank for a water heater. The hot water storage tank is made up of body portion 201 and a pair of end portions 202. Body portion 201 is, for example, a cylindrical object manufactured by rolling a thin plate. End portion 202 is a bowl-shaped object made from a thin plate. The material forming the hot water storage tank may be, for example, a steel plate such as stainless steel plate.

[0131] Body portion 201 is disposed so as to be sandwiched between the pair of end portions 202. End portion 202 is welded to the end surface of body portion 201 by welding equipment 300. That is, the portion where body portion 201 and end portion 202 are connected to each other is weld portion A.

[0132] Welding equipment 300 mainly includes welding apparatus 100 according to any of Embodiments 1 to 4, a holding mechanism portion 301, and a rotation mechanism portion 302. Holding mechanism portion 301 holds workpiece 200. Rotation mechanism portion 302 rotates workpiece 200. In Embodiment 5, holding mechanism portion 301 holds end portions 202. End portions 202 are connected to body portion 201. That is, with end portions 202 kept in contact with the opposite ends of body portion 201, the workpiece is grasped by welding equipment 300. Workpiece 200 is welded while body portion 201 and the pair of end portions 202 are rotated by rotation mechanism portion 302. In this way, the hot water storage tank into which body portion 201 and the pair of end portions 202 are assembled to be integrated is manufactured.

[0133] <Welding Method> Next, a welding method using welding equipment 300 including second keeping mechanism portion 22y shown in Fig. 17 is described.

[0134] Initially, a preparing step is performed. In this step, workpiece 200 and welding equipment 300 are prepared as shown in Fig. 19. Welding apparatus 100 includes second keeping mechanism portion 22y shown in Fig. 17. Workpiece 200 is a cylindrical structure or a can body such as hot water storage tank, made up of body portion 201 and a pair of end portions 202. With end portions 202 kept in contact with the opposite ends of body portion 201, the workpiece is grasped by holding mechanism portion 301.

[0135] Subsequently, a moving step is performed. In this step, workpiece 200 is moved to the vicinity of welding apparatus 100. Specifically, workpiece 200 is moved to be brought into contact with first keeping mechanism portion 22x and second keeping mechanism portion 22y. Each of first keeping mechanism portion 22x and second keeping mechanism portion 22y is in contact with the surface of either body portion 201 or end portion 202.

[0136] Subsequently, a welding step is performed. In this step, workpiece 200 is welded. Specifically, workpiece 200 is rotated by rotation mechanism portion 302. Welding torch 1 generates an arc toward workpiece 200. A post shielding gas is blown from gas supply portion 20 toward workpiece 200. As workpiece 200 is displaced due to eccentricity or the like at this time, the distance between shielding portion 21 and workpiece 200 is kept constant by first keeping mechanism portion 22x even when workpiece 200 rotates. Moreover, the distance between welding torch 1 and workpiece 200 is kept constant by the second keeping mechanism portion 22y. That is, the relative position of shielding portion 21 and the relative position of welding torch 1 with respect to workpiece 200 are determined independently of each other. Thus, body portion 201 and end portions 202 are welded in the state where weld portion A of workpiece 200 is sufficiently shielded from the atmosphere by the post shielding gas.

[0137] In this way, a hot water storage tank into which body portion 201 and a pair of end portions 202 are assembled to be integrated is manufactured.

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

[0139] Initially, a preparing step is performed. In this step, workpiece 200 and welding equipment 300 are prepared as shown in Fig. 19. Welding apparatus 100 includes processing circuit 3 shown in Fig. 18. Workpiece 200 is a hot water storage tank made up of body portion 201 and a pair of end portions 202. With end portions 202 kept in contact with the opposite ends of body portion 201, the workpiece is grasped by holding mechanism portion 301.

[0140] Subsequently, a moving step is performed. In this step, workpiece 200 is moved to the vicinity of welding apparatus 100. Specifically, workpiece 200 is moved to be brought into contact with first keeping mechanism portion 22. First keeping mechanism portion 22 is in contact with the surface of either body portion 201 or end portion 202.

[0141] Subsequently, a welding step is performed. In this step, workpiece 200 is welded. Specifically, workpiece 200 is rotated by rotation mechanism portion 302. Welding torch 1 generates an arc toward workpiece 200. A post shielding gas is blown from gas supply portion 20 toward workpiece 200. As workpiece 200 is displaced due to eccentricity or the like at this time, the distance between shielding portion 21 and workpiece 200 is kept constant by first keeping mechanism portion 22 even when workpiece 200 rotates. Meanwhile, the distance between welding torch 1 and workpiece 200 is adjusted by drive unit 2. Specifically, the distance between welding torch 1 and workpiece 200 is adjusted based on the voltage of the arc generated from electrode portion la. That is, the relative position of shielding portion 21 and the relative position of welding torch 1 with respect to workpiece 200 are determined independently of each other. Thus, body portion 201 and end portion 202 are welded in the state where weld portion A of workpiece 200 is sufficiently shielded from the atmosphere by the post shielding gas.

[0142] In this way, a hot water storage tank into which body portion 201 and a pair of end portions 202 are assembled to be integrated is manufactured.

[0143] <Functions and Effects> Welding equipment 300 according to the present disclosure includes welding apparatus 100, holding mechanism portion 301, and rotation mechanism portion 302. Holding mechanism portion 301 holds workpiece 200. Rotation mechanism portion 302 rotates workpiece 200.

[0144] Thus, a cylindrical structure such as hot water storage tank can be welded in the state where the relative position of shielding portion 21 and the relative position of welding torch 1 with respect to workpiece 200 are determined independently of each other. At this time, the post shielding gas sufficiently shields weld portion A of workpiece 200 from the atmosphere.

[0145] A welding method according to the present disclosure includes the steps of: moving workpiece 200 to the vicinity of welding apparatus 100; and welding workpiece 200. In the moving step, workpiece 200 is moved to be brought into contact with first keeping mechanism portion 22x. In the welding step, welding torch 1 generates an arc toward workpiece 200. In the welding step, a post shielding gas is blown from gas supply portion 20 toward workpiece 200. In the welding step, the distance between shielding portion 21 and workpiece 200 is kept constant by first keeping mechanism portion 22x. In the welding step, the distance between welding torch 1 and workpiece 200 is kept constant by second keeping mechanism portion 22y.

[0146] Thus, the cylindrical structure such as hot water storage tank can be welded in the state where the relative position of shielding portion 21 and the relative position of welding torch 1 with respect to workpiece 200 are determined independently of each other. At this time, the post shielding gas sufficiently shields weld portion A of workpiece 200 from the atmosphere.

[0147] A welding method according to the present disclosure includes the steps of: moving workpiece 200 to the vicinity of welding apparatus 100; and welding workpiece 200. In the moving step, workpiece 200 is moved to be brought into contact with first keeping mechanism portion 22. In the welding step, welding torch 1 generates an arc toward workpiece 200. In the welding step, a post shielding gas is blown from gas supply portion 20 toward workpiece 200. In the welding step, the distance between shielding portion 21 and workpiece 200 is kept constant by first keeping mechanism portion 22. In the welding step, the distance between welding torch 1 and workpiece 200 is adjusted by drive unit 2.

[0148] Thus, the cylindrical structure such as hot water storage tank can be welded in the state where the relative position of shielding portion 21 and the relative position of welding torch 1 with respect to workpiece 200 are determined independently of each other. At this time, the post shielding gas sufficiently shields weld portion A of workpiece 200 from the atmosphere.

[0149] It should be construed that the embodiments disclosed herein are given by way of illustration in all respects, not by way of limitation. At least two of the embodiments disclosed herein may be combined as long as there is no inconsistency. It is intended that the basic scope of the present disclosure is defined by claims, not by the description above, and encompasses all modifications and variations equivalent in meaning and scope to the claims.

[0150] In the following, various aspects of the present disclosure are described together in the form of supplementary notes. (Supplementary Note 1) A post shielding gas jig including a gas supply portion including a discharge portion to enable a post shielding gas to blow from the discharge portion toward a workpiece, wherein the gas supply portion includes a shielding portion and a first keeping mechanism portion, the shielding portion is disposed to surround the discharge portion as seen in a direction in which the post shielding gas blows, and the first keeping mechanism portion enables a distance between the shielding portion and the workpiece to be kept constant independently of a position of a welding torch. (Supplementary Note 2) The post shielding gas jig according to Supplementary Note 1, including: a rail connected to the gas supply portion; and a first connecting portion slidable on the rail, wherein the first connecting portion is capable of holding the welding torch. (Supplementary Note 3) The post shielding gas jig according to Supplementary Note 1 or 2, including a cover connected to the gas supply portion, wherein the cover is flame-retardant. (Supplementary Note 4) The post shielding gas jig according to Supplementary Note 3, wherein a material forming the cover includes any of glass fiber, ceramic-based fiber, and carbon fiber. (Supplementary Note 5) The post shielding gas jig according to any one of Supplementary Notes 1 to 4, wherein the post shielding gas is enabled to blow in a direction perpendicular to a tangent line to the workpiece and in a direction along the tangent line. (Supplementary Note 6) The post shielding gas jig according to any one of Supplementary Notes 1 to 5, wherein the welding torch is disposed in an X direction as seen from the discharge portion, the shielding portion includes a front surface and a rear surface opposite to the front surface in the X direction, and the first keeping mechanism portion includes a rotatable roller disposed in a region from the rear surface to 50% or less of a distance from the rear surface to the front surface in the X direction, or a region from the rear surface to the welding torch. (Supplementary Note 7) The post shielding gas jig according to any one of Supplementary Notes 1 to 6, wherein a position adjusting portion is provided between the shielding portion and the first keeping mechanism portion, and the position adjusting portion changes a relative position of the first keeping mechanism portion with respect to the shielding portion. (Supplementary Note 8) The post shielding gas jig according to any one of Supplementary Notes 1 to 7, wherein the shielding portion is provided with a link member, and a relative position of the link member with respect to the shielding portion is changed. (Supplementary Note 9) The post shielding gas jig according to any one of Supplementary Notes 1 to 8, wherein the shielding portion includes a movable portion that is slidable. (Supplementary Note 10) The post shielding gas jig according to any one of Supplementary Notes 1 to 9, wherein the shielding portion includes an inclined portion on which the welding torch is to be mounted. (Supplementary Note 11) The post shielding gas jig according to Supplementary Note 10, wherein the inclined portion is formed by a curved surface. (Supplementary Note 12) A welding apparatus including: the welding torch; and the post shielding gas jig according to any one of Supplementary Notes 1 to 11. (Supplementary Note 13) The welding apparatus according to Supplementary Note 12, wherein the welding torch includes an electrode portion, and a central axis of the electrode portion is inclined with respect to a tangent line to the workpiece. (Supplementary Note 14) The welding apparatus according to Supplementary Note 12 or 13, including a second connecting portion connected to the welding torch, wherein the second connecting portion includes a second keeping mechanism portion, and the second keeping mechanism portion enables a distance between the welding torch and the workpiece to be kept constant. (Supplementary Note 15) The welding apparatus according to any one of Supplementary Notes 12 to 14, including: a drive unit connected to the welding torch; and a processing circuit to detect a voltage of an arc generated from the welding torch, wherein the drive unit adjusts a distance between the welding torch and the workpiece based on the voltage. (Supplementary Note 16) The welding apparatus according to any one of Supplementary Notes 12 to 15, wherein the welding torch is disposed in an X direction as seen from the discharge portion, the shielding portion includes a front surface and a rear surface opposite to the front surface in the X direction, and the first keeping mechanism portion includes a rotatable roller disposed in a region from the rear surface to 50% or less of a distance from the rear surface to the front surface in the X direction, or a region from the rear surface to the welding torch. (Supplementary Note 17) The welding apparatus according to any one of Supplementary Notes 12 to 16, wherein a position adjusting portion is provided between the shielding portion and the first keeping mechanism portion, and the position adjusting portion changes a relative position of the first keeping mechanism portion with respect to the shielding portion. (Supplementary Note 18) The welding apparatus according to any one of Supplementary Notes 12 to 17, wherein the shielding portion is provided with a link member, and a relative position of the link member with respect to the shielding portion is changed. (Supplementary Note 19) The welding apparatus according to any one of Supplementary Notes 12 to 18, wherein the shielding portion includes a movable portion that is slidable. (Supplementary Note 20) The welding apparatus according to any one of Supplementary Notes 12 to 19, wherein the shielding portion includes an inclined portion on which the welding torch is to be mounted. (Supplementary Note 21) The welding apparatus according to Supplementary Note 20, wherein the inclined portion is formed by a curved surface. (Supplementary Note 22) A welding equipment including: the welding apparatus according to any one of Supplementary Notes 12 to 21; a holding mechanism portion to hold the workpiece; and a rotation mechanism portion to rotate the workpiece. (Supplementary Note 23) A welding method including: to a vicinity of the welding apparatus according to Supplementary Note 14, moving the workpiece; and welding the workpiece, wherein the moving includes moving the workpiece to bring the workpiece into contact with the first keeping mechanism portion, and the welding includes: causing the welding torch to generate an arc toward the workpiece; causing the post shielding gas to be blown from the gas supply portion toward the workpiece; keeping constant, by the first keeping mechanism portion, the distance between the shielding portion and the workpiece; and keeping constant, by the second keeping mechanism portion, the distance between the welding torch and the workpiece. (Supplementary Note 24) A welding method including: to a vicinity of the welding apparatus according to Supplementary Note 15, moving the workpiece; and welding the workpiece, wherein the moving includes moving the workpiece to bring the workpiece into contact with the first keeping mechanism portion, and the welding includes: causing the welding torch to generate an arc toward the workpiece; causing the post shielding gas to be blown from the gas supply portion toward the workpiece; keeping constant, by the first keeping mechanism portion, the distance between the shielding portion and the workpiece; and adjusting, by the drive unit, the distance between the welding torch and the workpiece. (Supplementary Note 25) The welding method according to Supplementary Note 23 or 24, wherein the workpiece is a cylindrical structure. (Supplementary Note 26) A method of 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, wherein the body portion and the pair of end portions constitute the cylindrical structure. REFERENCE SIGNS LIST

[0151] 1 welding torch; la electrode portion; 1c central axis; 2 drive unit; 3 processing circuit; 3a control unit; 3b detection unit; 10 post shielding gas jig; 20 gas supply portion; 21 shielding portion; 21a upper side shielding portion; 21b rear side shielding portion; 21c lateral side shielding portion; 21d front side shielding portion; 21 f filter; 21g protruding portion; 21h discharge portion; 21r, 25d curved surface portion; 21s discharge surface; 22, 22x first keeping mechanism portion; 22a ball roller; 22b bracket; 22c shaft portion; 22d rotatable roller; 221' columnar part; 22y second keeping mechanism portion; 23 position adjusting portion; 23g link member; 23g 1 shaft portion; 23g2 fixing member; 24 cover; 25 lower surface; 25a horizontal portion; 25b, 26 inclined portion; 25c linear portion; 25sl rear surface; 25s2 front surface; 30, 30y rail; 31, 3 ly stopper; 40, 40x first connecting portion; 40y second connecting portion; 41, 4 ly sliding portion; 42, 42y first block portion; 43, 43y second block portion; 44, 44y arm portion; 45y third block portion; 51 pipe joint; 52 diffusion plate; 81 body portion; 82 movable portion; 83 linked member; 84 coupling portion; 100 welding apparatus; 200 workpiece; 201 body portion; 202 end portion; 300 welding equipment; 301 holding mechanism portion; 302 rotation mechanism portion; A weld portion; QI region; hl, h2, h3, h4 through hole.

Claims

1. A post shielding gas jig comprising a gas supply portion including a discharge portion to enable a post shielding gas to blow from the discharge portion toward a workpiece, whereinthe gas supply portion includes a shielding portion and a first keeping mechanism portion,the shielding portion is disposed to surround the discharge portion as seen in a direction in which the post shielding gas blows, andthe first keeping mechanism portion enables a distance between the shielding portion and the workpiece to be kept constant independently of a position of a welding torch.

2. The post shielding gas jig according to claim 1, comprising:a rail connected to the gas supply portion; anda first connecting portion slidable on the rail, whereinthe first connecting portion is capable of holding the welding torch.

3. The post shielding gas jig according to claim 1, comprising a cover connected to the gas supply portion, whereinthe cover is flame-retardant.[Claim 4J The post shielding gas jig according to claim 3, wherein a material forming the cover includes any of glass fiber, ceramic-based fiber, and carbon fiber.

5. The post shielding gas jig according to claim 1, wherein the post shielding gas is enabled to blow in a direction perpendicular to a tangent line to the workpiece and in a direction along the tangent line.

6. The post shielding gas jig according to any one of claims 1 to 5, whereinthe welding torch is disposed in an X direction as seen from the discharge portion,the shielding portion includes a front surface and a rear surface opposite to the front surface in the X direction, andthe first keeping mechanism portion includes a rotatable roller disposed in a region from the rear surface to 50% or less of a distance from the rear surface to the front surface in the X direction, or a region from the rear surface to the welding torch.

7. The post shielding gas jig according to any one of claims 1 to 6, whereina position adjusting portion is provided between the shielding portion and the first keeping mechanism portion, andthe position adjusting portion changes a relative position of the first keeping mechanism portion with respect to the shielding portion.

8. The post shielding gas jig according to any one of claims 1 to 7, whereinthe shielding portion is provided with a link member, anda relative position of the link member with respect to the shielding portion is changed.

9. The post shielding gas jig according to any one of claims 1 to 8, wherein the shielding portion includes a movable portion that is slidable.

10. The post shielding gas jig according to any one of claims 1 to 9, wherein the shielding portion includes an inclined portion on which the welding torch is to be mounted.

11. The post shielding gas jig according to claim 10, wherein the inclined portion is formed by a curved surface.

12. A welding apparatus comprising:the welding torch; andthe post shielding gas jig according to any one of claims 1 to 5.

13. The welding apparatus according to claim 12, whereinthe welding torch includes an electrode portion, anda central axis of the electrode portion is inclined with respect to a tangent line to the workpiece.

14. The welding apparatus according to claim 12, comprising a second connecting portion connected to the welding torch, whereinthe second connecting portion includes a second keeping mechanism portion, andthe second keeping mechanism portion enables a distance between the welding torch and the workpiece to be kept constant.

15. The welding apparatus according to claim 12, comprising:a drive unit connected to the welding torch; anda processing circuit to detect a voltage of an arc generated from the welding torch, whereinthe drive unit adjusts a distance between the welding torch and the workpiece based on the voltage.

16. A welding equipment comprising:the welding apparatus according to claim 12;a holding mechanism portion to hold the workpiece; anda rotation mechanism portion to rotate the workpiece.

17. A welding method comprising:to a vicinity of the welding apparatus according to claim 14, moving the workpiece; andwelding the workpiece, whereinthe moving includes moving the workpiece to bring the workpiece into contact with the first keeping mechanism portion, andthe welding includes:causing the welding torch to generate an arc toward the workpiece;causing the post shielding gas to be blown from the gas supply portion toward the workpiece;keeping constant, by the first keeping mechanism portion, the distance between the shielding portion and the workpiece; andkeeping constant, by the second keeping mechanism portion, the distance between the welding torch and the workpiece.

18. A welding method comprising:to a vicinity of the welding apparatus according to claim 15, moving the workpiece; andwelding the workpiece, whereinthe moving includes moving the workpiece to bring the workpiece into contact with the first keeping mechanism portion, andthe welding includes:causing the welding torch to generate an arc toward the workpiece;causing the post shielding gas to be blown from the gas supply portion toward the workpiece;keeping constant, by the first keeping mechanism portion, the distancebetween the shielding portion and the workpiece; andadjusting, by the drive unit, the distance between the welding torch and the workpiece.5

19. The welding method according to claim 17, wherein the workpieceis a cylindrical structure.

20. A method of manufacturing a cylindrical structure using the welding method according to any one of claims 17 to 19, wherein10 the workpiece is a body portion and a pair of end portions, wherein the bodyportion and the pair of end portions constitute the cylindrical structure.INTERNATIONAL SEARCH REPORT International application No. PCT / JP2024 / 022005A. CLASSIFICATION OF SUBJECT MATTER B23K 9 / 2912006.0l)i FI: B23K9 / 29 L According to International Patent Classification (IPC) or to both national classification and IPC B. FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) B23K9 / 29 Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched Published examined utility model applications of Japan 1922-1996 Published unexamined utility model applications of Japan 1971-2024 Registered utility model specifications of Japan 1996-2024 Published registered utility model applications of Japan 1994-2024 Electronic data base consulted during the international search (name of data base and, where practicable, search terms used) C. DOCUMENTS CONSIDERED TO BE RELEVANT Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. X Y A Y A JP 2022-99822 A (KABUSHIKI KAISHA KOBE SEIKO SHO) 05 July 2022 (2022-07-05) paragraphs [0011]-[0012], [0022]-[0025], [0035]-[0036], [0047]-[0048], fig. 1-4 JP 9-164482 A (NKK CORP.) 24 June 1997 (1997-06-24) paragraph [0002] 1,7, 12-14 15 2-6, 8-11, 16-20 1-14, 16-20 A Microfilm of the specification and drawings annexed to the request of Japanese Utility Model Application No. 176848 / 1979 (Laid-open No. 95479 / 1981) (MITSUBISHI ELECTRIC CORP.) 29 July 1981 (1981-07-29). entire text, all drawings 1-20 A JP 2022-149068 A (TAIYO NIPPON SANSO CORPORATION) 06 October 2022 (2022-10-06) entire text, all drawings 1-20 | | Further documents are listed in the continuation of Box C. | f | See patent family annex. * Special categories of cited documents: “A” document defining the general state of the art which is not considered to be of particular relevance ■‘D” document cited by the applicant in the international application “E” earlier application or patent but published on or after the international filing date “L” document which may throw doubts on priority claim(s) or which is cited to establish the publication date of another citation or other special reason (as specified) “O” document referring to an oral disclosure, use, exhibition or other means “P” document published prior to the international filing date but later than the priority date claimed “T” later document published after the international filing date or priority date and not in conflict with the application but cited to understand the principle or theory underlying the invention “X” document of particular relevance; the claimed invention cannot be considered novel or cannot be considered to involve an inventive step when the document is taken alone “Y” document of particular relevance; the claimed invention cannot be considered to involve an inventive step when the document is combined with one or more other such documents, such combination being obvious to a person skilled in the ait document member of the same patent family Date of the actual completion of the international search 23 July 2024 Date of mailing of the international search report 06 August 2024 Name and mailing address of the ISA / JP Japan Patent Office (ISA / JP) 3-4-3 Kasumigaseki, Chiyoda-ku, Tokyo 100-8915 Japan Authorized officer Telephone No.INTERNATIONAL SEARCH REPORT International application No. PCT / JP2024 / 022005C. DOCUMENTS CONSIDERED TO BE RELEVANTCategory* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. A JP 2003-1491 A (SHINBA IRON WORKS INC.) 08 January 2003 (2003-01-08) entire text, all drawings 1-20INTERNATIONAL SEARCH REPORT Information on patent family members International application No. PCT / JP2024 / 022005Patent document cited in search report Publication date (day / month / year) Patent family member) s) Publication date (day / month / year) JP 2022-99822 A 05 July 2022 (Family: none) JP 9-164482 A 24 June 1997 (Family: none) JP 56-95479 UI 29 July 1981 (Family: none) JP 2022-149068 A 06 October 2022 (Family: none) JP 2003-1491 A 08 January 2003 (Family: none)

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