Protective clamps and gas-shielded arc welding equipment

Abstract

The protective clamp comprises: a first housing member that covers the periphery of the welding torch and is disposed with a radial gap between it and the welding torch, and divides a first annular space having a first opening at the bottom; a first gas supply member disposed inside the first housing member that surrounds the welding torch and supplies protective gas to the first annular space; and a dispersion member disposed in the first annular space at a position lower than the first gas supply member and disperses the protective gas.

Description

Technical Field

[0001] This invention relates to protective clamps and gas-shielded arc welding apparatus. Background Technology

[0002] Gas-shielded arc welding is known in which a shielding gas (inactive gas) is supplied to the weld portion, thereby shielding the weld portion from air to prevent oxidation. The welding torch used in such gas-shielded arc welding is described, for example, in Patent Document 1.

[0003] The welding torch in Patent Document 1 has the following structure: the shielding gas passage and the control gas passage for controlling the cross-sectional shape of the weld bead are each an independent passage, and these passages are arranged in a longitudinal row at a position symmetrical about the welding arc and the welding direction. Accordingly, Patent Document 1 describes how, in welding with narrow bevels, by setting up a front shielding gas passage and a rear shielding gas passage to control the gas flow rate, the cross-sectional shape of the weld bead and the penetration are improved.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 1-48678 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Furthermore, in gas-shielded arc welding using base materials or filler materials (welding wire) composed of active metals, the affinity of the active metals for the atmosphere is particularly strong at high temperatures, readily reacting with oxygen and nitrogen in the air to form oxides and nitrides. Therefore, the hardening and brittleness of the oxide and nitride-forming areas after welding become significant. Thus, in gas-shielded arc welding of active metals, post-shielding fixtures are typically used to implement localized gas protection near the welding torch to prevent contact between the atmosphere and the active metal. However, when layering filler materials such as pure titanium or titanium alloys, it is still difficult to suppress the intrusion of oxygen and nitrogen into the weldment to below specified values ​​simply by using post-shielding fixtures.

[0009] For example, in the direction of welding travel, there is air, oxygen, and nitrogen adhering to the base material and other components, making it difficult to prevent their entrapment. Furthermore, current protective fixtures have a narrow protective area covered by the shielding gas, making it difficult to ensure gas protection for the surrounding high-temperature weld beads adjacent to the weld beads during stacking. Moreover, depending on the welding travel direction, the gas protection may become insufficient, creating limitations in stacking operations performed by robotic arms.

[0010] Therefore, the object of the present invention is to provide a protective fixture and a gas shielded arc welding apparatus that can consistently ensure gas protection over a wide range during gas shielded arc welding.

[0011] Solution for solving the problem

[0012] The present invention is composed of the following structure.

[0013] (1) A protective clamp, which is mounted on a welding torch used for protective welding to melt and solidify a metallic filler material to form a weld bead, wherein,

[0014] The protective clamp has the following features:

[0015] A first outer shell member covers the periphery of the welding torch and is configured with a radial gap between it and the welding torch, and divides a first annular space having a first opening at the bottom;

[0016] A first gas supply component, disposed inside the first housing component surrounding the welding torch, supplies protective gas to the first annular space; and

[0017] A dispersion component is disposed in the first annular space below the first gas supply component, and disperses the protective gas.

[0018] (2) A gas-shielded arc welding apparatus, wherein,

[0019] The gas-shielded arc welding apparatus includes the protective clamp described in (1).

[0020] Invention Effects

[0021] According to the present invention, a wide range of gas protection can be consistently and stably ensured during gas-shielded arc welding. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the gas-shielded arc welding apparatus.

[0023] Figure 2 It is a perspective view of the protective nozzle at the front end of the welding torch and the protective clamp of the first structural example set on the outer periphery of the protective nozzle.

[0024] Figure 3 This is a schematic cross-sectional view showing the internal structure of the protective nozzle.

[0025] Figure 4 This is a schematic cross-sectional view showing the internal structure of the protective clamp of the first structural example.

[0026] Figure 5This is an illustrative diagram schematically showing the welding torch during welding and the flow of protective gas generated by the protective fixture of the first structural example.

[0027] Figure 6A This is a schematic top view showing the weld bead formed using a protective clamp.

[0028] Figure 6B This is a schematic side view showing the weld bead formed using a protective clamp.

[0029] Figure 7 This is a graph showing the relationship between the oxygen content and nitrogen content in the weld beads of each test example shown in Figure 6.

[0030] Figure 8 This is a schematic cross-sectional view showing the internal structure of the protective clamp of the second structural example.

[0031] Figure 9 This is an illustrative diagram schematically showing the welding torch during welding and the flow of protective gas generated by the protective fixture of the second structural example.

[0032] Figure 10 This is a perspective view showing a modified protective clamp in which a flow straightening section for controlling the flow direction of the protective gas is provided in the protective clamp of the second structural example.

[0033] Figure 11A This is a partial cross-sectional view of the bottom of the protective clamp, used to illustrate the situation of protective gas being ejected from the protective clamp.

[0034] Figure 11B This refers to the air curtain formed when protective gas is ejected from a protective clamp. Figure 11A The XI-XI line sectional view shown. Detailed Implementation

[0035] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0036] The protective clamp of the present invention is described here using the case of forming a stacked object by gas-shielded arc welding as an example, but the present invention is not limited thereto.

[0037] Figure 1 This is a schematic diagram of the gas-shielded arc welding apparatus.

[0038] The gas-shielded arc welding apparatus 100, which is a manufacturing device for layered shapes, includes a welding robot 11, a robot drive unit 13, a filler material supply unit 15, a shielding gas supply unit 17, a welding power source unit 19, and a control unit 21.

[0039] The welding robot 11 is a jointed robot, and a welding torch 23 is supported on its front end axis. The position and orientation of the welding torch 23 can be arbitrarily set in three dimensions within the range of the robot arm's degrees of freedom. The welding torch 23 holds the filler material M continuously supplied from the filler material supply unit 15 in a state that protrudes from the front end of the welding torch.

[0040] The shielding gas supply unit 17 supplies inert gases to the welding section. In MIG welding, argon, helium (or a mixture thereof), or gases containing small amounts of reactive gases such as oxygen and carbon dioxide are used as shielding gases. On the other hand, in MAG welding, carbon dioxide or a mixture of argon and carbon dioxide is used as the shielding gas, while in TIG welding, argon is used. Furthermore, in laser welding, nitrogen, argon, helium, etc., are used as shielding gases.

[0041] The welding torch 23 is a protective welding torch used to melt and solidify a metallic filler material M to form a weld bead. Specifically, the welding torch 23 has a protective nozzle 25 that receives the protective gas supplied from the protective gas supply unit 17 (see reference). Figures 2-5 ), and supply shielding gas to the welding part from the shielding nozzle 25. As an arc welding method, it can be any of the consumable electrode types such as covered arc welding or carbon dioxide gas arc welding, or the non-consumable electrode types such as TIG welding or plasma arc welding, and the appropriate type is selected according to the stacked shape being produced.

[0042] The heat source for melting the filler material M is not limited to the electric arc described above. For example, other heat sources based on methods such as heating with both electric arc and laser, heating with plasma, or heating with electron beam or laser can also be used. When heating with electron beam or laser, the amount of heat can be controlled more precisely, and the state of the weld bead can be maintained more appropriately, which helps to further improve the quality of the laminated structure.

[0043] The filler material used is pure titanium or a titanium alloy, such as titanium or titanium alloy welding wire (e.g., refer to JIS Z 3331). If the filler material is pure titanium or a titanium alloy, proper welding can be performed even when the base material is titanium-based. It should be noted that the filler material is not limited to the above-mentioned materials and can also be other materials.

[0044] A protective clamp 31 is installed on the outer periphery of the welding torch 23. The protective clamp 31 is supplied with protective gas from the protective gas supply unit 17 and sprays the protective gas toward the welding part. Details of the protective clamp 31 will be described later.

[0045] The robot drive unit 13 receives instructions from the control unit 21 to drive the various parts of the welding robot 11 and controls the output of the welding power supply as needed.

[0046] The control unit 21 is a computer device equipped with a CPU, memory, storage, etc., which executes a pre-prepared driver program or a driver program created under desired conditions to drive the various parts of the welding robot 11 and the like. As a result, the welding torch 23 is moved according to the driver program, and multiple layers of weld beads B are deposited on the base plate 29, thereby creating a multi-layered structure.

[0047] <First Structural Example>

[0048] Figure 2 This is a perspective view of the protective nozzle 25 at the front end of the welding torch 23 and the protective clamp 31 of the first structural example provided on the outer periphery of the protective nozzle 25.

[0049] As described above, the shielding gas supply unit 17 supplies shielding gas to both the welding torch 23 and the shielding fixture 31. The shielding nozzle 25 of the welding torch 23 has a filler material M protruding from the nozzle tip, and sprays the shielding gas G0 supplied from the shielding gas supply unit 17 toward the welding section below.

[0050] Figure 3 This is a schematic cross-sectional view showing the internal structure of the protective nozzle 25.

[0051] The protective nozzle 25 shown here is a consumable electrode type. A conductive tip 27 is disposed inside the protective nozzle 25, and the filler material M, supplied with molten current, is held in the conductive tip 27. While holding the filler material M, the welding torch 23 generates an arc from the tip of the filler material M under a shielding gas atmosphere. The filler material M is... Figure 1 A feed mechanism (not shown) installed on a portion of the welding robot 11 feeds the material onto the welding torch 23. By melting and solidifying the continuously fed filler material M while the torch 23 moves, a weld bead B, consisting of the molten and solidified filler material M, is formed on the base plate 29. At this time, shielding gas G0 supplied from the shielding gas supply unit 17 is injected from the torch 23 through an internal space S0 defined within the shielding nozzle 25, providing gas protection around the filler material M.

[0052] In addition, Figure 2 The protective clamp 31 shown is connected to a first gas supply pipe 33. The front end of the first gas supply pipe 33 penetrates the upper surface of the protective clamp 31 and is inserted into the clamp, and is connected to an annular first hollow pipe 35. The first hollow pipe 35 is positioned above the first annular space S1 inside the clamp, and has a plurality of injection ports 35a formed at equal intervals along its circumference. The protective gas G1 supplied from the first gas supply pipe 33 is injected upward from the injection ports 35a of the first hollow pipe 35, and then downward towards the first annular space S1.

[0053] Figure 4This is a schematic cross-sectional view showing the internal structure of the protective clamp 31 of the first structural example.

[0054] A protective clamp 31 is disposed on the outer periphery of a protective nozzle 25 disposed at the front end of the welding torch 23. The protective clamp 31 includes a first housing member 32A, a first gas supply member 38A, and a dispersion member 41.

[0055] The first outer shell member 32A covers the periphery of the welding torch 23 and is arranged with a radial gap on the outer side of the outer peripheral surface of the welding torch 23, and divides a first annular space S1 with a first opening 37A at the bottom. The first outer shell member 32A is composed of a metal plate member whose outer peripheral surface is formed into a generally cylindrical shape. A hole is provided in the center of the upper surface of the first outer shell member 32A, through which the protective nozzle 25 passes. The first outer shell member 32A and the protective nozzle 25 are fixed by appropriate methods such as welding, threaded fastening, or clamping mechanism. The material and structure of the first outer shell member 32A are not particularly limited.

[0056] The first gas supply member 38A is configured to include a first gas supply pipe 33 and a first hollow pipe 35. The first gas supply pipe 33 is a straight hollow pipe that penetrates the upper surface of the first outer shell member 32A. The first hollow pipe 35 is an annular hollow pipe disposed in the first annular space S1, and has a plurality of injection ports 35a for supplying protective gas on its upper surface. That is, the first gas supply member 38A is disposed in the first annular space S1 in such a way that it at least surrounds the outer peripheral surface of the welding torch 23, and the plurality of injection ports 35a for supplying protective gas are arranged with the injection direction set upward. Protective gas is supplied to the first hollow pipe 35 through the first gas supply pipe 33 and is uniformly injected over the entire circumference of the first hollow pipe 35 from the injection ports 35a above the first hollow pipe 35. Afterward, the injected protective gas flows downward into the first annular space S1, and after passing through the dispersing member 41 supported by the holding member 42, reaches the first opening 37A formed on the bottom surface of the first annular space S1.

[0057] The dispersion member 41 is positioned below the first gas supply member 38A in the first annular space S1, and serves to disperse the protective gas supplied from the first gas supply member 38A within the first annular space S1. A hole is provided in the center of the dispersion member 41, through which the protective nozzle 25 passes. The outer periphery of the dispersion member 41 has a circular shape that contacts the inner circumferential surface of the first outer shell member 32A. The dispersion member 41 is made of, for example, a fibrous component such as glass wool or steel wool, and disperses the protective gas within the first annular space S1. The material of the dispersion member 41 can also be other than those described above, and is not particularly limited.

[0058] The retaining member 42 has a hole in its center, through which the protective nozzle 25 passes. The outer periphery of the retaining member 42 has a circular shape that contacts the inner peripheral surface of the first outer shell member 32A. The retaining member 42 can be made of, for example, a stainless steel mesh member through which the protective gas can pass, but the material and shape of the retaining member 42 are not particularly limited. In addition, the retaining member 42 can have a mesh size of 0.1 mm to 1.0 mm, preferably 0.3 mm to 0.7 mm, to have a gas rectification function. In this case, the retaining member 43 also functions as a dispersing member.

[0059] The outer periphery of the retaining member 42 is fixed to the inner peripheral surface of the first outer shell member 32A by welding or the like, and the dispersing member 41 is placed or attached to the upper surface of the retaining member 42. Therefore, the retaining member 42 can stably hold the dispersing member 41 in the first annular space S1.

[0060] Furthermore, although not shown in the figure, the flow path of the protective gas can be restricted by providing a shielding member (such as a heat insulation strip) for the protective gas in the retaining member 42, and the release area and flow rate of the protective gas can be easily adjusted. It should be noted that the retaining member 42 may also have the outer periphery of the dispersing member 41 directly joined to the inner peripheral surface of the first outer shell member 32A. In this case, the retaining member 42 can be omitted.

[0061] In the protective fixture 31 with the above-described structure, a first hollow tube 35 surrounding the welding torch 23 sprays protective gas, and a dispersion member 41 disperses the protective gas flowing in the first annular space S1. Therefore, according to this protective fixture 31, compared with fixtures used in ordinary welding such as rear protective fixtures, gas protection can be provided over a wider range and more evenly over the entire circumference of the weld.

[0062] In addition, the bottom of the first outer shell member 32A has a narrowing portion 45 that gradually decreases in radius along the axial direction of the welding torch 23, but it can also be composed of a straight cylindrical body without the narrowing portion 45.

[0063] Here, the outer circumference d0 of the welding torch 23 (protective nozzle 25) and the outer circumference d1 of the first outer shell member 32A have a relationship of d1 > d0. In addition, when the flow rate of the protective gas ejected from the first opening 37A, which is the opening of the first annular space S1, is set as Vout, and the total valve flow rate of the protective gas supplied to the first annular space S1 is set as Vin, the flow rate Vout of the protective gas from the first opening 37A is obtained by mathematical formula (1).

[0064] [Mathematical Formula 1]

[0065]

[0066] That is, the protective clamp 31 sets the total valve velocity Vin of the protective gas, the outer circumference d0 of the welding torch 23, and the outer circumference d1 of the first housing member 32A in such a way that the flow rate Vout of the protective gas injected from below the first annular space S1 is 113.17 mm / s or more. Here, the total valve velocity Vin of the protective gas is equivalent to the gas velocity corresponding to the gas supply pressure generated by the protective gas supply unit 17.

[0067] In this way, by setting the flow rate Vout of the shielding gas injected from the first annular space S1 to 113.17 mm / s or more, a sufficient amount of shielding gas can flow forward in the welding travel direction, effectively suppressing the entrainment of air, oxygen, nitrogen, etc., adhering to various components into the weld. Furthermore, by setting the outer circumference d1 of the first outer shell member 32A to a predetermined size or larger, the weld bead that is close to the weld and may become hot can be contained within the shielding gas atmosphere. Therefore, reliable gas protection can be ensured. Moreover, by ensuring the size (radius distance) of the first outer shell member 32A, variations in gas protection caused by the welding direction can be suppressed, increasing the degree of freedom in the shaping of the welding robot.

[0068] That is, by properly setting the inner and outer circumferences of the first outer casing member 32A according to the flow rate of the protective gas used, a higher gas protection effect can be obtained.

[0069] The first opening 37A, which serves as the outlet for the protective gas, has the same annular shape as the cross-section of the first annular space S1. Therefore, the protective gas G1 ejected from the first opening 37A forms a cylindrical curtain. The first opening 37A has a continuous annular shape along the circumference, but is not limited to this. It can also be configured as a structure in which multiple openings are arranged along the circumference. The shape of the first opening 37A is not particularly limited.

[0070] Figure 5 This is an explanatory diagram schematically showing the welding torch 23 during welding and the flow of protective gas generated by the protective fixture 31 of the first structural example.

[0071] The welding torch 23 moves to deposit multiple layers of weld beads B on the base plate 29, thereby forming a multi-layered structure W. At this time, protective gas G0 is injected from the protective nozzle 25 at the front end of the welding torch 23. In addition, the protective fixture 31 injects the protective gas G1 supplied to the first annular space S1 in an annular pattern from the entire circumference of the first opening 37A toward the base plate 29.

[0072] The shielding gas G1 ejected from the first opening 37A forms a cylindrical air curtain. The shielding gas G1 serves to trap the shielding gas G0 ejected from the welding torch 23 into the interior of the formed air curtain and to block the inflow of external air Air. As a result, the weld bead B during welding is effectively isolated from external air, oxygen, nitrogen, etc. adhering to other components, and can suppress the intrusion of impurities into the stacked structure W.

[0073] Furthermore, due to the narrowing portion 45 at the bottom of the first housing member 32A, the injection direction of the shielding gas G2 from the shielding fixture 31 approaches one side of the welding torch 23. As a result, the position where the shielding gas G0 from the welding torch 23 touches the weld is close to the position where the shielding gas G1 from the shielding fixture 31 touches the weld, which can be expected to improve the retention effect of the shielding gas.

[0074] Figure 6A This is a schematic top view showing the weld bead formed using a protective clamp. Figure 6B This is a schematic side view showing the weld bead formed using a protective clamp.

[0075] In this test example, two types of protective fixtures with an outer circumference d1 of φ100mm (Test Example 1) and φ150mm (Test Example 2) were prepared. Under the following conditions, 3 rows of 3 layers of weld beads B were formed on the base plate 29.

[0076] Filler material: Titanium wire (manufactured by Tadong Special Steel Co., Ltd.)

[0077] Welding speed: 20 cpm

[0078] Filler material feed rate: 6.2 MPa

[0079] Protective gas: Argon

[0080] Shielding gas supply to the welding torch: 20L / min

[0081] Protective gas supply rate to the protective clamp: 50 L / min

[0082] Shaft length of protective clamp: 50mm

[0083] outer diameter of welding torch: φ25mm

[0084] The annular diameter of the first hollow tube is φ80mm.

[0085] Retaining component: Stainless steel mesh with a mesh size of 0.5mm.

[0086] The formation sequence of weld bead B is in Figure 6BThe numbers are used to indicate the weld beads. The formation of weld beads B was carried out by making two samples in each of Experimental Examples 1 and 2, for a total of four samples.

[0087] Figure 7 It is shown Figure 6A , Figure 6B The graph shows the relationship between oxygen and nitrogen content in weld bead B of each test example. In all test examples, the intrusion of both oxygen and nitrogen was suppressed to a low level, especially in test example 2, where both oxygen and nitrogen contents were lower compared to test example 1. This is believed to be because, with the supply of shielding gas to the shielding fixture set to a constant value, a smaller outer circumference d1 results in a faster gas flow rate ejected from the shielding fixture, improving gas protection and suppressing air entrapment caused by arc heat.

[0088] The flow rate of the shielding gas injected from the first opening 37A was 48.05 mm / s in Test Example 1 and 113.17 mm / s in Test Example 2. A flow rate higher than that in Test Example 2 more reliably suppresses the intrusion of impurities, enabling better welding.

[0089] <Second structural example>

[0090] Figure 8 This is a schematic cross-sectional view showing the internal structure of the protective clamp 31A of the second structural example.

[0091] In addition to the structure of the protective clamp 31 in the first structural example, the protective clamp 31A of this structure also includes a second outer shell member 32B and a second gas supply member 38B.

[0092] The second outer shell member 32B is arranged with a radial gap on the outer side of the outer peripheral surface of the first outer shell member 32A, dividing a second annular space S2 between itself and the first outer shell member 32A. The upper part of the second annular space S2 is blocked by the cover part 39, and the bottom of the second annular space S2 has a second opening 37B. The outer peripheral surface of the second outer shell member 32B is cylindrical, and when the outer peripheral diameter of the welding torch 23 (protective nozzle 25) is set as d0, the outer peripheral diameter of the first outer shell member 32A is set as d1, and the inner peripheral diameter of the second outer shell member 32B is set as d2, d2 > d1 > d0 holds true.

[0093] The second outer shell member 32B is composed of a metal plate member formed into a generally cylindrical shape. A hole is provided in the center of the upper surface of the second outer shell member 32B, and the first outer shell member 32A is fixed in the hole. The material, structure, etc. of the second outer shell member 32B are not particularly limited.

[0094] The second gas supply member 38B is configured to include a second gas supply pipe 34 and a second hollow pipe 36. The second gas supply pipe 34 is a straight hollow pipe that penetrates the upper surface of the second outer shell member 32B. The second hollow pipe 36 is an annular hollow pipe arranged in the second annular space S2, and has a plurality of injection ports 36a for supplying protective gas on its upper surface. That is, the second gas supply member 38B is arranged in the second annular space S2 such that it at least surrounds the outer peripheral surface of the first outer shell member 32A, and the plurality of injection ports 36a are arranged with the injection direction of the protective gas set upward. The protective gas supplied through the second gas supply pipe 34 is supplied to the second hollow pipe 36 and is uniformly injected around the circumference of the second hollow pipe 36 from the injection ports 36a. Afterward, the injected protective gas flows downward into the second annular space S2 and reaches the second opening 37B formed on the bottom surface of the second annular space S2.

[0095] Figure 9 This is an explanatory diagram schematically showing the welding torch 23 during welding and the flow of protective gas generated by the protective fixture 31A of the second structural example.

[0096] The welding torch 23 moves to deposit multiple layers of weld beads B on the base plate 29, thereby forming a multi-layered structure W. At this time, the protective nozzle 25 at the front end of the welding torch 23 sprays shielding gas G0 together with filler material M. In addition, the protective fixture 31A sprays shielding gas G1 supplied to the first annular space S1 and shielding gas G2 supplied to the second annular space S2 in an annular pattern from the entire circumference of the first opening 37A and the second opening 37B toward the front end of the welding torch 23.

[0097] The shielding gas G1 ejected from the first opening 37A forms a cylindrical air curtain. The shielding gas G1 serves to trap the shielding gas G0 ejected from the welding torch 23 inside the formed air curtain and prevent the inflow of external air Air. As a result, the weld bead B during welding is effectively isolated from external air, oxygen, nitrogen, etc. adhering to other components, and can inhibit the intrusion of impurities into the stacked structure W.

[0098] Furthermore, the shielding gas G2 ejected from the second opening 37B also forms a cylindrical air curtain. The shielding gas G2 serves to trap the shielding gas G0 ejected from the welding torch 23 and the shielding gas G1 ejected from the first opening 37A within the formed air curtain, blocking the inflow of external air. In this case, due to the difference in the opening area at the bottom, the ejection speed of the shielding gas G2 is faster than that of the shielding gas G1. Thus, the outer shielding gas G2 traps the inner shielding gas G1, forming a double air curtain. Therefore, under the combined effect of the shielding gases G1 and G2, the intrusion of impurities from the outside into the stacked structure W can be further suppressed.

[0099] Furthermore, a narrowing portion 45 is formed at the bottom of the second outer shell member 32B, with the radius of the second outer shell member 32B gradually decreasing along the axial direction of the welding torch 23. Along with the formation of this narrowing portion 45, a corresponding narrowing portion 46 is also formed at the bottom of the first outer shell member 32A. The radial gap between the narrowing portions 45 and 46 is constant along the circumference and is set to be approximately equal to the size of the radial gap outside the bottom (d2-d1) / 2. Therefore, the point where the shielding gases G0, G1, and G2 collide is closer to the side of the welding torch 23, which is expected to further improve the retention effect of the shielding gases. It should be noted that the protective clamp 31A can also be constructed as a straight cylindrical body without the narrowing portions 45 and 46.

[0100] Furthermore, when the outer circumference of the welding torch 23 is set to d0, the outer circumference of the first outer shell component 32A is set to d1, and the inner circumference of the second outer shell component 32B is set to d2, the relative dimensions of the first outer shell component 32A and the second outer shell component 32B are designed relative to the welding torch 23 in such a way that d1 - d0 > d2 - d1 holds. As a result, the radial width of the first annular space S1 is larger than the radial width of the second annular space S2, which saves on the amount of shielding gas.

[0101] That is, in this structure, the protective gas supply source is a single protective gas supply unit 17 ( Figure 2The shielding gas supply unit 17 supplies shielding gas to the welding torch 23, the first gas supply member 38A, and the second gas supply member 38B, respectively. To ensure a stable supply of shielding gas G0 from the welding torch 23, the shielding gas supply unit 17 controls the supply of shielding gas to a predetermined constant amount. Therefore, the supply pressure of the shielding gas in the welding torch 23 is controlled to be constant. At this time, the shielding fixture 31A is subjected to the same gas supply pressure as the welding torch 23 and ejects shielding gas G1 and shielding gas G2. Therefore, the smaller the cross-sectional area of ​​the second annular space S2, the faster the flow rate of shielding gas G2. Thus, it is easy to generate an air curtain with different flow rates on the inner and outer circumferential sides, improving gas protection. Furthermore, since the air curtain on the outer circumferential side with a faster flow rate is thinner than the air curtain on the inner circumferential side with a slower flow rate, gas consumption is suppressed.

[0102] Furthermore, after the air in the first annular space S1 has been purged, the supply of protective gas G1 can be stopped, and protective gas can only be supplied to the second annular space S2. In this case, it is possible to maintain sufficient gas protection while saving on protective gas consumption.

[0103] <Variation Example>

[0104] Figure 10 This is a perspective view showing the outline structure of a modified protective clamp 31B, which includes a flow straightening section 47 for controlling the flow direction of the protective gas G2 in the protective clamp 31A of the second structural example. Figure 10 The image shows only the lower portion of the second gas supply member 38B within the second housing member 32B.

[0105] In the modified example, the protective clamp 31B has a rectifier 47 provided in the second annular space S2 inside the second housing member 32B. The other structures are the same as those of the aforementioned protective clamp 31A.

[0106] The rectifier 47 is disposed in the second annular space S2 and causes the flow of the protective gas G2 to be spiral. The rectifier 47 can be formed, for example, by a fin 49 of a metal plate disposed between the outer surface of the first housing member 32A and the inner surface of the second housing member 32B.

[0107] The fins 49 are arranged at equal intervals along the circumference and divide the space into multiple rows of spiral gas flow paths 51. The protective gas G2 flowing in each gas flow path 51 is restricted in its flow direction by the fins 49 and is ejected as a spiral airflow from the second opening 37B. This forms an annular air curtain that rotates along the circumference.

[0108] The rectifying section 47 is composed of fins 49, but is not limited to this. For example, spiral holes or grooves, such as those of a fretwork, may be formed on the outer peripheral surface of the first housing member 32A or the inner peripheral surface of the second housing member 32B. Alternatively, the rectifying section 47 may be configured such that multiple nozzles for injecting protective gas are arranged at the bottom of the second annular space S2 with the injection direction inclined in the circumferential direction.

[0109] Figure 11A This is a partial cross-sectional view of the bottom of the protective clamp 31B, used to illustrate the situation of protective gas G2 being injected from the protective clamp 31B. Figure 11B This is used to illustrate the air curtain formed when protective gas G2 is injected from protective clamp 31B. Figure 11A The XI-XI line sectional view shown.

[0110] like Figure 11A As shown, the protective gas G2 injected from the second opening 37B of the second annular space S2 is formed into a spiral-shaped air curtain CT under the action of the aforementioned rectifying section 47, as... Figure 11B As shown, it becomes a continuous annular shape in cross-section.

[0111] By applying a rotating motion to the shielding gas using the spiral-shaped air curtain CT, the inflow of air into the weld can be more reliably prevented, further improving the gas shielding effect on the weld. Furthermore, the shielding gas is ejected while rotating, thus preventing the entrapment of residual air in the shielding gas piping. In this case, after the air present in the first annular space S1 is removed, the supply of shielding gas G1 can be stopped, and shielding gas can be supplied only to the second annular space S2, thereby saving shielding gas consumption.

[0112] It should be noted that an additional suction path can be set inside the air curtain to attract the fumes generated during welding.

[0113] The protective clamps 31, 31A, and 31B described above have a cylindrical shape centered on the welding torch 23, thus forming an annular air curtain centered on the welding torch 23. Therefore, a gas protection effect is achieved for any direction of movement of the welding torch 23 without restricting its trajectory. For example, compared to front and rear protection provided according to the direction of travel of the welding torch 23, the restriction on the direction of movement of the welding torch 23 can be suppressed, thus enabling welding with a high degree of freedom in construction.

[0114] Thus, the present invention is not limited to the above-described embodiments. Combining the various structures of the embodiments with each other, as well as making changes and applications based on the description and well-known techniques by those skilled in the art, are also intended by the present invention and are included within the scope of the claimed protection.

[0115] As stated above, the following matters are disclosed in this specification.

[0116] (1) A protective clamp, which is mounted on a welding torch used for protective welding to melt and solidify a metallic filler material to form a weld bead, wherein,

[0117] The protective clamp has the following features:

[0118] A first outer shell member covers the periphery of the welding torch and is configured with a radial gap between it and the welding torch, and divides a first annular space having a first opening at the bottom;

[0119] A first gas supply component, disposed inside the first housing component surrounding the welding torch, supplies protective gas to the first annular space; and

[0120] A dispersion component is disposed in the first annular space below the first gas supply component, and disperses the protective gas.

[0121] This protective fixture enables gas protection over a wide range of areas around the welded portion.

[0122] (2) The protective clamp according to (1), wherein,

[0123] When the flow rate of the protective gas ejected from the first opening is set to Vout, the total valve flow rate of the protective gas supplied to the first annular space is set to Vin, the outer circumference of the welding torch is set to d0, and the outer circumference of the first outer shell component is set to d1, mathematical formula (2) holds true regarding the flow rate Vout of the protective gas.

[0124] [Mathematical Formula 2]

[0125] .

[0126] This protective clamp can effectively prevent impurities from being drawn into the weld.

[0127] (3) The protective clamp according to (1) or (2), wherein,

[0128] The protective clamp also includes a retaining member that is mounted on the inner circumferential surface of the first housing member in the first annular space and holds the dispersing member.

[0129] According to the protective clamp, the dispersed components can be stably held in the first annular space.

[0130] (4) The protective clamp according to (3), wherein,

[0131] The retaining member is provided with a shielding member that restricts the passage of the protective gas.

[0132] According to this protective clamp, a shielding component is provided on the retaining component, thereby allowing the flow rate of the protective gas and the position of the gas being sprayed from the retaining component to be adjusted freely.

[0133] (5) The protective clamp according to any one of (1) to (4), wherein,

[0134] The protective clamp also features:

[0135] A second outer shell member is disposed radially away from the outer periphery of the first outer shell member, and divides a second annular space between itself and the first outer shell member, having a cover at the top and a second opening at the bottom; and

[0136] The second gas supply component supplies the protective gas to the second annular space.

[0137] This protective clamp can further improve the effect of preventing impurities from entering the weld.

[0138] (6) The protective clamp according to (5), wherein,

[0139] When the outer circumference of the welding torch is set to d0, the outer circumference of the first outer shell component is set to d1, and the inner circumference of the second outer shell component is set to d2,

[0140] The statement d1-d0>d2-d1 holds true.

[0141] According to this protective clamp, the difference in radial length between the outer periphery of the first outer shell member and the outer periphery of the welding torch is greater than the radial width of the annular space. Therefore, protective gas can be injected even at a position where the welding torch is separated from the radial width of the first annular space. As a result, the protective gas can be retained in the space centered on the welding torch.

[0142] (7) The protective clamp according to (6), wherein,

[0143] The statement d0 > d2 - d1 holds true.

[0144] According to this protective fixture, the radial width of the annular space is smaller than the outer circumference of the welding torch, which can increase the flow rate of the protective gas injected from the annular space and improve the gas protection effect.

[0145] (8) The protective clamp according to any one of (5) to (7), wherein,

[0146] A flow straightener is provided in the second annular space to make the flow direction of the protective gas spiral.

[0147] This protective clamp can more reliably prevent air from flowing into the weld, further improving the gas protection effect of the weld. Furthermore, the protective gas is ejected while rotating, thus preventing the entrapment of residual air in the protective gas piping.

[0148] (9) The protective clamp according to any one of (5) to (8), wherein,

[0149] At least at the bottom of the second housing member, a narrowing portion is formed such that the radius of the second housing member gradually decreases along the axial direction of the welding torch.

[0150] According to the protective fixture, the point where the protective gas ejected from the welding torch collides with the protective gas ejected from the second annular space is close to one side of the welding torch, which can be expected to improve the retention effect of the protective gas.

[0151] (10) The protective clamp according to any one of (1) to (9), wherein,

[0152] The filler material is pure titanium or a titanium alloy.

[0153] This protective clamp enables high-quality welding even on base materials that are susceptible to oxygen and nitrogen intrusion.

[0154] (11) A gas-shielded arc welding apparatus, wherein,

[0155] The gas-shielded arc welding apparatus includes any one of (1) to (10) a protective clamp.

[0156] According to this gas-shielded arc welding device, high gas protection is achieved, enabling stable gas-shielded arc welding.

[0157] It should be noted that this application is based on Japanese patent application filed on August 6, 2021 (Japanese Patent Application No. 2021-129974), the contents of which are referenced in this application.

[0158] Explanation of reference numerals in the attached figures

[0159] 11 Welding Robots

[0160] 13 Robot Drive Department

[0161] 15. Filler Material Supply Department

[0162] 17. Protective Gas Supply Department

[0163] 19 Welding Power Supply Section

[0164] 21 Control Department

[0165] 23 Welding torches

[0166] 25 Protect the nozzle

[0167] 27. Conductive tip

[0168] 29 Base Plate

[0169] 31, 31A, 31B Protective clamps

[0170] 32A First outer shell component

[0171] 32B Second Shell Component

[0172] 33 First gas supply pipe

[0173] 34 Second gas supply pipe

[0174] 35 First Hollow Tube

[0175] 36 Second Hollow Tube

[0176] 37A First Opening

[0177] 37B Second Opening

[0178] 38A First Gas Supply Component

[0179] 38B Second Gas Supply Component

[0180] 41 Dispersion Components

[0181] 42 Retaining components

[0182] 45 Narrowing section

[0183] 47 Rectifier Section

[0184] 49 Fins

[0185] 51 Gas Flow Path

[0186] 100 Gas-Shielded Arc Welding Equipment

[0187] B weld bead

[0188] G0, G1, G2 protective gases

[0189] M Filler Material

[0190] S0 interior space

[0191] S1 First Circular Space

[0192] S2 Second Annular Space

[0193] W - Layered shapes.

Claims

1. A protective clamp, mounted on a welding torch used for protective welding to melt and solidify a metallic filler material to form a weld bead, wherein, The protective clamp has the following features: A first outer shell member covers the periphery of the welding torch and is configured with a radial gap between it and the welding torch, and divides a first annular space having a first opening at the bottom; A first gas supply component is disposed inside the first housing component, surrounding the welding torch, and supplies protective gas to the first annular space. A dispersing component is disposed in the first annular space at a position lower than the first gas supply component, and disperses the protective gas; The second outer shell member is disposed radially on the outer side of the outer peripheral surface of the first outer shell member, and divides a second annular space between it and the first outer shell member, having a cover at the top and a second opening at the bottom. as well as The second gas supply component supplies the protective gas to the second annular space. When the outer circumference of the welding torch is set to d0, the outer circumference of the first outer shell component is set to d1, and the inner circumference of the second outer shell component is set to d2, The statement d1-d0>d2-d1 holds true.

2. The protective clamp according to claim 1, wherein, When the flow rate of the protective gas ejected from the first opening is set to Vout, the total valve flow rate of the protective gas supplied to the first annular space is set to Vin, the outer circumference of the welding torch is set to d0, and the outer circumference of the first outer shell component is set to d1, mathematical formula (1) holds true regarding the flow rate Vout of the protective gas. [Mathematical Formula 1] 。 3. The protective clamp according to claim 1, wherein, The protective clamp also includes a retaining member that is mounted on the inner circumferential surface of the first housing member in the first annular space and holds the dispersing member.

4. The protective clamp according to claim 2, wherein, The protective clamp also includes a retaining member that is mounted on the inner circumferential surface of the first housing member in the first annular space and holds the dispersing member.

5. The protective clamp according to claim 3, wherein, The retaining member is provided with a shielding member that restricts the passage of the protective gas.

6. The protective clamp according to claim 4, wherein, The retaining member is provided with a shielding member that restricts the passage of the protective gas.

7. The protective clamp according to claim 1, wherein, The statement d0 > d2 - d1 holds true.

8. The protective clamp according to claim 1, wherein, A flow straightener is provided in the second annular space to make the flow direction of the protective gas spiral.

9. The protective clamp according to claim 7, wherein, A flow straightener is provided in the second annular space to make the flow direction of the protective gas spiral.

10. The protective clamp according to claim 1, wherein, At least at the bottom of the second housing member, a narrowing portion is formed such that the radius of the second housing member gradually decreases along the axial direction of the welding torch.

11. The protective clamp according to claim 7, wherein, At least at the bottom of the second housing member, a narrowing portion is formed such that the radius of the second housing member gradually decreases along the axial direction of the welding torch.

12. The protective clamp according to claim 8, wherein, At least at the bottom of the second housing member, a narrowing portion is formed such that the radius of the second housing member gradually decreases along the axial direction of the welding torch.

13. The protective clamp according to any one of claims 1 to 6, wherein, The filler material is pure titanium or a titanium alloy.

14. A gas-shielded arc welding apparatus, wherein, The gas-shielded arc welding apparatus comprises the protective clamp as described in any one of claims 1 to 6.

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