Arc welding equipment

Abstract

Provided is an arc welding device with which base materials having different plate thicknesses, shapes, or the like can be welded together with good quality in a narrow workspace. An arc welding device 1 welds together a first base material 80 and a second base material 90, each having a flat section 81, 91 and a bent section 82, 92, the flat sections 81, 91 extending in a direction in which the flat sections approach each other, and the bent sections 82, 92 bending from the flat sections 81, 91 and extending in a direction intersecting the flat sections 81, 91 and abutting against each other. The arc welding device comprises: a welding electrode 11; a first ground electrode 20 that extends along the bent section 82 of the first base material 80 and abuts against the flat section 81 of the first base material 80; and a second ground electrode 30 that extends along the bent section 92 of the second base material 90 and abuts against the flat section 91 of the second base material 90. The first ground electrode 20 and the second ground electrode 30, independently of each other, respectively abut against the flat section 81 of the first base material 80 and the flat section 91 of the second base material 90.

Description

[Technical Field]

[0001] The present invention relates to an arc welding device. [Background technology]

[0002] In power conversion devices, terminals of power modules and bus bars are often joined by arc welding. As power conversion devices become smaller and thinner, the working space for welding the terminals and bus bars becomes smaller. A smaller working space increases the likelihood of interference with surrounding components, making it difficult to ground the terminals and bus bars using a chuck mechanism that clamps and secures them. Therefore, a smaller working space makes it difficult to ensure the required welding quality.

[0003] Patent Document 1 discloses a welding device comprising a nozzle formed in the shape of a bottomed cylindrical body having an opening, and a welding heat source accommodated and disposed inside the nozzle, configured to weld the joined bodies while generating spatter with the welding heat source in a state where the peripheral edge of the nozzle opening is in contact with the joined bodies. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-193019 Summary of the Invention [Problem to be solved by the invention]

[0005] In a power conversion device that is intended to be miniaturized and low-profile, the plate thickness or shape, etc., may not be the same between the terminals of the power module and the bus bar. The welding device disclosed in Patent Document 1 does not take into consideration the case where the plate thickness or shape, etc., of the terminals of the power module and the bus bar are not the same, which may make it difficult to ensure the required welding quality. This problem is not limited to power conversion devices, but also occurs in devices that must weld base materials having different plate thicknesses or shapes, etc., in a narrow working space.

[0006] The present invention has been made in consideration of the above, and aims to provide an arc welding device that can weld base materials having different thicknesses or shapes with high quality in a small working space. [Means for solving the problem]

[0007] In order to solve the above problem, the arc welding apparatus of the present invention is an arc welding apparatus for welding a first base metal and a second base metal, each of which has a flat portion and a bent portion, with the flat portions extending in directions approaching each other and the bent portions bent from the flat portions to extend in a direction intersecting the flat portions and abutting each other, and is characterized in that it comprises: a welding electrode arranged opposite the abutment portion of the bent portion of the first base metal and the bent portion of the second base metal; a first earth electrode extending along the bent portion of the first base metal and abutting the flat portion of the first base metal; and a second earth electrode extending along the bent portion of the second base metal and abutting the flat portion of the second base metal, [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an arc welding device that can weld base materials having different thicknesses or shapes with high quality in a small working space. Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an exploded perspective view of a power conversion device including a welding target of an arc welding device according to an embodiment of the present invention; [Figure 2] FIG. 2 is an enlarged view of a main part of the cross section taken along line AA in FIG. 1. [Figure 3] 1 is a schematic diagram showing the configuration of an arc welding device according to an embodiment of the present invention; [Figure 4] 4 is a schematic diagram of a cross section of line BB shown in FIG. 3. [Figure 5] 5 is a diagram illustrating another example of a first earth electrode having a shape different from that of FIG. 4. FIG. [Figure 6] 10A and 10B are diagrams illustrating the operation of the load adjusting mechanism when the first base material and the second base material have the same shape. [Figure 7] 10A and 10B are diagrams illustrating the operation of the load adjusting mechanism when the first base material and the second base material have different shapes. [Figure 8] 10A and 10B are diagrams illustrating the operation of the load adjusting mechanism when the first base material and the second base material have different shapes. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that components with the same reference numerals in each embodiment have the same functions in each embodiment unless otherwise specified, and description thereof will be omitted.

[0011] Fig. 1 is an exploded perspective view of a power converter 100 having an object to be welded by an arc welding device 1 according to this embodiment. Fig. 2 is an enlarged view of a main part of the cross section taken along line AA shown in Fig. 1.

[0012] The power conversion device 100 includes a housing 110, a power module 120 that has a semiconductor device and performs power conversion, and a connector and a bus bar that are electrically connected to the semiconductor device of the power module 120. The power conversion device 100 also includes electronic components such as a molded bus bar 130, a capacitor 140, and a noise filter circuit 150 that are disposed within the housing 110 and electrically connected to the power module 120.

[0013] 1 is a dual type that controls the input and output of two motors, and has two power modules 120 arranged in parallel. However, the power conversion device 100 is not limited to the dual type shown in FIG.

[0014] The power module 120 is composed of a semiconductor device that converts DC power into AC power and a pair of cooling channels that sandwich the semiconductor device. The cooling channels may be provided on only one side of the semiconductor device.

[0015] The bus bars included in the power conversion device 100 of this embodiment include an AC bus bar 160 and a DC bus bar 170. The AC bus bar 160 is electrically connected to an AC terminal 121, which is an input / output unit for AC power of the power module 120. The DC bus bar 170 is electrically connected to a DC terminal 122, which is an input / output unit for DC power of the power module 120. The AC bus bar 160 and the AC terminal 121 are arranged opposite to each other. The DC bus bar 170 and the DC terminal 122 are arranged opposite to each other. Each of the AC bus bar 160, the DC bus bar 170, the AC terminal 121, and the DC terminal 122 is made of a metal plate, such as a copper plate, bent into an L shape.

[0016] In this embodiment, an arc welding apparatus 1 that joins an AC terminal 121 or a DC terminal 122 of a power module 120 to an AC bus bar 160 or a DC bus bar 170 by arc welding will be described as an example. That is, the AC terminal 121 or the DC terminal 122 and the AC bus bar 160 or the DC bus bar 170 constitute a first base material 80 and a second base material 90 to be welded by the arc welding apparatus 1.

[0017] Fig. 3 is a schematic diagram showing the configuration of the arc welding device 1 of this embodiment. Fig. 4 is a schematic diagram of a cross section taken along line BB shown in Fig. 3. Fig. 5 is a diagram illustrating another example of the first earth electrode 20 having a shape different from that shown in Fig. 4.

[0018] The arc welding apparatus 1 welds a first base material 80 and a second base material 90 that are butted against each other and face each other. The first base material 80 has a flat portion 81 and a bent portion 82 that bends from the flat portion 81 and extends in an intersecting direction (upward) of the flat portion 81 toward the welding electrode 11. The second base material 90 has a flat portion 91 and a bent portion 92 that bends from the flat portion 91 and extends in an intersecting direction (upward) of the flat portion 91 toward the welding electrode 11.

[0019] The bent portion 82 of the first base material 80 and the bent portion 92 of the second base material 90 abut against each other. The bent portion 82 of the first base material 80 and the bent portion 92 of the second base material 90 may extend upward from below the welding electrode 11 toward the welding electrode 11. The tip end surface (upper end surface) of the bent portion 82 of the first base material 80 and the tip end surface (upper end surface) of the bent portion 92 of the second base material 90 are arranged facing the welding electrode 11 with a gap therebetween. The tip end surface of the bent portion 82 of the first base material 80 and the tip end surface of the bent portion 92 of the second base material 90 are welding surfaces where an arc discharge is generated between them and the welding electrode 11, and a weld P is formed. The tip end surface of the bent portion 82 of the first base material 80 and the tip end surface of the bent portion 92 of the second base material 90 may be at the same height from a reference plane. The reference surface may be the top surface of a table or the like on which an apparatus such as a power conversion device 100 having a first base material 80 and a second base material 90 is placed, or the top surface of a table or the like on which the first base material 80 and the second base material 90 are placed.

[0020] The flat portion 81 of the first base material 80 and the flat portion 91 of the second base material 90 extend in a direction approaching each other. That is, the flat portion 81 of the first base material 80 and the flat portion 91 of the second base material 90 do not overlap each other when viewed in the direction of the arrows along which the bent portions 82, 92 extend. The flat portion 81 of the first base material 80 and the flat portion 91 of the second base material 90 may extend in a direction perpendicular to the abutment surface between the bent portion 82 of the first base material 80 and the bent portion 92 of the second base material 90, in a direction approaching the abutment surface. The flat portion 81 of the first base material 80 and the flat portion 91 of the second base material 90 may differ from each other in plate thickness or shape, for example, may differ from each other in height from a reference plane.

[0021] The arc welding device 1 is, for example, a TIG (Tungsten Inert Gas) welding machine. The arc welding device 1 includes a welding torch 10, a first earth electrode 20, a second earth electrode 30, and a pressing mechanism 40.

[0022] The welding torch 10 includes a welding electrode 11 that generates an arc discharge between the first base material 80 and the second base material 90. The welding electrode 11 is connected to the negative electrode of the welding power source 2. The welding electrode 11 may be formed using tungsten, which is less consumed by welding. The welding electrode 11 is arranged opposite, but spaced apart from, the abutting portion between the bent portion 82 of the first base material 80 and the bent portion 92 of the second base material 90. The welding electrode 11 may be arranged opposite, but spaced apart from, the tip surfaces of the bent portion 82 of the first base material 80 and the bent portion 92 of the second base material 90. The welding electrode 11 may be arranged facing downward.

[0023] The first earth electrode 20 and the second earth electrode 30 are each connected to the positive electrode of the welding power source 2. The first earth electrode 20 extends along the bent portion 82 of the first base material 80 and is formed in a plate shape that abuts against the flat portion 81 of the first base material 80. The first earth electrode 20 may be formed in a plate shape that extends in a direction (downward) from the welding electrode 11 toward the bent portion 82 of the first base material 80. The second earth electrode 30 extends along the bent portion 92 of the second base material 90 and is formed in a plate shape that abuts against the flat portion 91 of the second base material 90. The second earth electrode 30 may be formed in a plate shape that extends in a direction (downward) from the welding electrode 11 toward the bent portion 92 of the second base material 90. The first earth electrode 20 and the second earth electrode 30 abut against the flat portion 81 of the first base material 80 and the flat portion 91 of the second base material 90, respectively, independently of each other.

[0024] The first ground electrode 20 and the second ground electrode 30 are disposed at a distance from each other. The welding torch 10, the welding electrode 11, the bent portion 82 of the first base material 80, and the bent portion 92 of the second base material 90 are disposed between the first ground electrode 20 and the second ground electrode 30. Each of the first ground electrode 20 and the second ground electrode 30 is formed using copper or a copper alloy material. At least the surface of each of the first ground electrode 20 and the second ground electrode 30 facing the welding electrode 11 is coated with an insulating material.

[0025] The tip portion 21 of the first earth electrode 20 abuts against the flat portion 81 of the first base material 80. The tip portion 31 of the second earth electrode 30 abuts against the flat portion 91 of the second base material 90. The tip surface of the tip portion 21 abutting against the flat portion 81 of the first base material 80 is parallel to the flat portion 81 of the first base material 80. The tip surface of the tip portion 31 abutting against the flat portion 91 of the second base material 90 is parallel to the flat portion 91 of the second base material 90. The tip surface of the first earth electrode 20 and the tip surface of the second earth electrode 30 may each have a flat shape or a curved shape that is rounded downward.

[0026] Each of the first earth electrode 20 and the second earth electrode 30 may be fixed to a moving mechanism that moves the welding torch 10, but it is preferable that they be fixed to a moving mechanism independent of the moving mechanism that moves the welding torch 10.

[0027] 4, the first earth electrode 20 has a width dimension W1 that intersects (is perpendicular to) the extension direction (vertical direction) and the plate thickness direction of the first earth electrode 20 and is larger than the width dimension W2 of the welding electrode 11. Furthermore, the width dimension W1 of the first earth electrode 20 may be larger than the width dimension W3 of the bent portion 82 of the first base material 80. Similarly, the second earth electrode 30 has a width dimension that intersects (is perpendicular to) the extension direction (vertical direction) and the plate thickness direction of the second earth electrode 30 and is larger than the width dimension W2 of the welding electrode 11. The width dimension of the second earth electrode 30 may be larger than the width dimension of the bent portion 92 of the second base material 90.

[0028] The first earth electrode 20 and the second earth electrode 30 having such a shape can surround at least the welding electrode 11. As a result, the first earth electrode 20 and the second earth electrode 30 can block the heat and light generated by the arc discharge even in a small working space, and can prevent the surrounding components from being burned.

[0029] Each of the first earth electrode 20 and the second earth electrode 30 only needs to have a shape wider than the welding electrode 11 so as to be able to block at least the heat and light generated by the arc discharge. For example, as shown in Fig. 5, the first earth electrode 20 may have a shape in which the dimension in the width direction is not constant from the tip end 21 to the base end 22 and extends obliquely when viewed in the plate thickness direction of the first earth electrode 20. The same applies to the second earth electrode 30.

[0030] A pressing mechanism 40 is connected to the base end 22 of the first earth electrode 20 and the base end 32 of the second earth electrode 30, respectively. The pressing mechanism 40 presses the first earth electrode 20 and the second earth electrode 30 against the flat portion 81 of the first base material 80 and the flat portion 91 of the second base material 90 with different loads. The pressing mechanism 40 connected to the first earth electrode 20 and the pressing mechanism 40 connected to the second earth electrode 30 are provided independently of each other. That is, the first earth electrode 20 presses the flat portion 81 of the first base material 80 by the pressing mechanism 40. The second earth electrode 30 presses the flat portion 91 of the second base material 90 by the pressing mechanism 40. The first earth electrode 20 and the second earth electrode 30 press the flat portion 81 of the first base material 80 and the flat portion 91 of the second base material 90 with different loads, respectively.

[0031] The pressing mechanism 40 includes an absorbing mechanism 50, a load detector 60, and a load adjusting mechanism 70.

[0032] The absorbing mechanism 50 is a mechanism that absorbs the difference in height between the flat portions 81, 91 of the first base material 80 and the second base material 90. The absorbing mechanism 50 is configured, for example, by a cylinder that houses a spring. The absorbing mechanism 50 has a structure that allows multiple types of springs with different multipliers to be replaced. The absorbing mechanism 50 may be configured by a mechanism that does not use a spring, such as an air cylinder. The absorbing mechanism 50 deforms in response to the first earth electrode 20 and the second earth electrode 30 pressing against the flat portions 81, 91, and returns to its original shape when the pressing is released. The absorbing mechanism 50 is insulated from the first earth electrode 20 and the second earth electrode 30. The absorbing mechanism 50 connected to the first earth electrode 20 and the absorbing mechanism 50 connected to the second earth electrode 30 are provided independently of each other.

[0033] The load detector 60 detects the pressing load of the first earth electrode 20 against the flat portion 81 of the first base material 80 and the pressing load of the second earth electrode 30 against the flat portion 91 of the second base material 90. The load detector 60 is configured by, for example, a pressure gauge. The load detector 60 can output the maximum value of the pressing load to a measuring instrument or the like. The load detector 60 is insulated from the first earth electrode 20 and the second earth electrode 30. The load detector 60 that detects the pressing load of the first earth electrode 20 and the load detector 60 that detects the pressing load of the second earth electrode 30 are provided independently of each other.

[0034] The load adjustment mechanism 70 adjusts the pressing load of the first earth electrode 20 against the flat portion 81 of the first base material 80 and the pressing load of the second earth electrode 30 against the flat portion 91 of the second base material 90. The load adjustment mechanism 70 is configured, for example, by a cylinder that houses a spring and a screw that expands and contracts the spring. The load adjustment mechanism 70 has a structure that allows replacement of multiple types of springs with different multipliers. The load adjustment mechanism 70 can adjust the pressing load by adjusting the deformation amount of the spring with the screw. The load adjustment mechanism 70 may also be configured by a mechanism that does not use a spring, such as an air cylinder. The load adjustment mechanism 70 is insulated from the first earth electrode 20 and the second earth electrode 30. The load adjustment mechanism 70 that adjusts the pressing load of the first earth electrode 20 and the load adjustment mechanism 70 that adjusts the pressing load of the second earth electrode 30 are provided independently of each other.

[0035] In the case shown in FIG. 3, the first base material 80 and the second base material 90 have different thicknesses, different lengths of the flat portions 81, 91, and different heights from the reference plane of the flat portions 81, 91. That is, the rigidity of the first base material 80 and the rigidity of the second base material 90 are different. In the case shown in FIG. 3, the thickness of the first base material 80 is greater than the thickness of the second base material 90. The length of the flat portion 91 of the second base material 90 is greater than the length of the flat portion 81 of the first base material 80. The height of the flat portion 91 of the second base material 90 is greater than the height of the flat portion 81 of the first base material 80. In this case, the load adjustment mechanism 70 makes the pressing load of the first earth electrode 20 greater than the pressing load of the second earth electrode 30. This allows the load adjustment mechanism 70 to adjust the pressing loads so that the amounts of deflection of the flat portions 81, 91 of the first base material 80 and the second base material 90 are the same and the amounts of displacement of the bent portions 82, 92 are the same.

[0036] FIG. 6 is a diagram illustrating the operation of the load adjustment mechanism 70 when the first base material 80 and the second base material 90 have the same shape.

[0037] 6, the first base material 80 and the second base material 90 have the same plate thickness, the same length of the flat portions 81, 91, and the same height from the reference plane of the flat portions 81, 91. That is, the rigidity of the first base material 80 and the rigidity of the second base material 90 are the same. In this case, the load adjustment mechanism 70 sets the pressing load of the first earth electrode 20 and the pressing load of the second earth electrode 30 to the same load. As a result, the load adjustment mechanism 70 can adjust each pressing load so that the amount of deflection of the flat portions 81, 91 of the first base material 80 and the second base material 90 is the same and the amount of displacement of the bent portions 82, 92 is the same.

[0038] FIG. 7 is a diagram illustrating the operation of the load adjustment mechanism 70 when the first base material 80 and the second base material 90 have different shapes.

[0039] In the case shown in FIG. 7, the first base material 80 and the second base material 90 have the same plate thickness, the same length of the flat portions 81, 91, but different heights from the reference plane of the flat portions 81, 91. That is, the rigidity of the first base material 80 and the rigidity of the second base material 90 are different. In the case shown in FIG. 7, the height of the flat portion 91 of the second base material 90 is higher than the height of the flat portion 81 of the first base material 80. That is, the length of the bent portion 92 of the second base material 90 is shorter than the length of the bent portion 82 of the first base material 80. In this case, the load adjustment mechanism 70 makes the pressing load of the second earth electrode 30 greater than the pressing load of the first earth electrode 20. As a result, the load adjustment mechanism 70 can adjust the pressing loads so that the amount of deflection of the flat portion 91 of the second base material 90 is greater than the amount of deflection of the flat portion 81 of the first base material 80, and the amount of displacement of the bent portions 82, 92 of the first base material 80 and the second base material 90 are the same. In the case shown in Fig. 7, the load adjustment mechanism 70 may make the pressing load of the second earth electrode 30 the same as the pressing load of the first earth electrode 20, as long as there is no large difference in the amount of displacement of the bent portions 82, 92 of the first base material 80 and the second base material 90.

[0040] FIG. 8 is a diagram illustrating the operation of the load adjustment mechanism 70 when the first base material 80 and the second base material 90 have different shapes.

[0041] In the example shown in FIG. 8, the first base material 80 and the second base material 90 have different thicknesses, the flat portions 81, 91 have the same length, and the flat portions 81, 91 have the same height from the reference plane. That is, the rigidity of the first base material 80 and the rigidity of the second base material 90 are different. In the example shown in FIG. 8, the thickness of the first base material 80 is greater than the thickness of the second base material 90. In this case, the load adjustment mechanism 70 makes the pressing load of the first earth electrode 20 greater than the pressing load of the second earth electrode 30. As a result, the load adjustment mechanism 70 can adjust the pressing loads so that the flat portions 81, 91 of the first base material 80 and the second base material 90 have the same amount of deflection and the bent portions 82, 92 have the same amount of displacement.

[0042] Next, a procedure for the arc welding apparatus 1 to perform welding work will be described with reference to FIG. 3. The arc welding apparatus 1 moves the first ground electrode 20 and the second ground electrode 30 to abut against the flat portion 81 of the first base material 80 and the flat portion 91 of the second base material 90. In the case shown in FIG. 3, as described above, the load adjustment mechanism 70 adjusts the pressing load of the first ground electrode 20 to be greater than the pressing load of the second ground electrode 30. The arc welding apparatus 1 detects with the load detector 60 that the spring constituting the absorption mechanism 50 has deformed and that the load value is the value adjusted by the load adjustment mechanism 70, and confirms that it is within the control range. Then, the arc welding apparatus 1 moves the welding torch 10 to a position suitable for welding. However, the first ground electrode 20, the second ground electrode 30, and the welding torch 10 may be fixed to the same moving mechanism.

[0043] Next, the arc welding device 1 selects welding conditions suitable for the first base material 80 and the second base material 90, and applies a welding current between the first base material 80 and the second base material 90, which are in contact with the first earth electrode 20 and the second earth electrode 30, and the welding electrode 11. At this time, the arc welding device 1 sprays shielding gas G from the welding torch 10 onto the bent portion 82 of the first base material 80 and the bent portion 92 of the second base material 90. The shielding gas G is an inert gas such as argon gas, and isolates the bent portion 82 and the bent portion 92 from the atmosphere to prevent oxidation.

[0044] An arc discharge occurs between the welding electrode 11 and the tip surfaces of the bent portions 82 of the first base material 80 and 92 of the second base material 90. A hemispherical weld P is formed between the tip surfaces of the bent portions 82 of the first base material 80 and 92 of the second base material 90, covering both the tip surfaces. By forming this hemispherical weld P, the arc welding apparatus 1 can increase the contact area of ​​the weld P with the first base material 80 and the second base material 90, thereby increasing the welding strength. In addition, by forming this hemispherical weld P, the arc welding apparatus 1 can easily visually inspect whether the first base material 80 and the second base material 90 are well welded. In other words, by forming this hemispherical weld P, the arc welding apparatus 1 can easily ensure the required welding quality.

[0045] Thereafter, the arc welding apparatus 1 cuts off the welding current, releases the pressure on the first ground electrode 20 and the second ground electrode 30, and removes them from the first base material 80 and the second base material 90. The arc welding apparatus 1 removes the welding torch 10 from the first base material 80 and the second base material 90. This completes the welding operation of the arc welding apparatus 1.

[0046] As described above, the arc welding apparatus 1 of this embodiment is an arc welding apparatus for welding a first base material 80 and a second base material 90, each of which has a flat portion 81, 91 and a bent portion 82, 92, with the flat portions 81, 91 extending in directions approaching each other and the bent portions 82, 92 bending from the flat portions 81, 91 to extend in a direction intersecting the flat portions 81, 91 and abutting each other. The arc welding apparatus 1 includes a welding electrode 11 disposed opposite the abutment portion of the bent portion 82 of the first base material 80 and the bent portion 92 of the second base material 90, a first earth electrode 20 extending along the bent portion 82 of the first base material 80 and abutting the flat portion 81 of the first base material 80, and a second earth electrode 30 extending along the bent portion 92 of the second base material 90 and abutting the flat portion 91 of the second base material 90. The first earth electrode 20 and the second earth electrode 30 are in contact with the flat portion 81 of the first base material 80 and the flat portion 91 of the second base material 90, respectively, independently of each other.

[0047] As a result, the arc welding apparatus 1 can easily ground the first earth electrode 20 and the second earth electrode 30 simply by moving the first earth electrode 20 along the direction in which the first earth electrode 20 extends and moving the second earth electrode 30 along the direction in which the second earth electrode 30 extends. That is, the arc welding apparatus 1 does not require the space required for opening and closing a chuck mechanism that clamps and grounds the bent portion 82 of the first base material 80 and the bent portion 92 of the second base material 90 from opposing directions of the first base material 80 and the second base material 90, as in the conventional case. Therefore, the arc welding apparatus 1 can perform welding work even in a small working space.

[0048] Furthermore, the arc welding apparatus 1 allows the first earth electrode 20 and the second earth electrode 30 to abut against the flat portion 81 of the first base metal 80 and the flat portion 91 of the second base metal 90, respectively, independently of each other. As a result, even if the plate thickness or shape, etc. of the first base metal 80 and the second base metal 90 are different, the arc welding apparatus 1 can appropriately abut and ground the first earth electrode 20 and the second earth electrode 30 against the respective flat portions 81, 91 in accordance with the plate thickness or shape, etc. of the first base metal 80 and the second base metal 90. Therefore, the arc welding apparatus 1 can prevent a deterioration in welding quality caused by an unstable arc discharge due to an insufficient grounding, which prevents the welding current from flowing stably.

[0049] Furthermore, the arc welding apparatus 1 can achieve earthing by having the first and second earth electrodes 20 and 30 abut against the flat portions 81 and 91, respectively, away from the tip surfaces of the bent portions 82 and 92, rather than abutting against the tip surfaces of the bent portions 82 and 92, which are the surfaces to be welded. This allows the arc welding apparatus 1 to form a hemispherical weld P that covers the tip surfaces of the bent portions 82 and 92. Therefore, the arc welding apparatus 1 can increase the contact area of ​​the weld P with the first base material 80 and the second base material 90, thereby increasing the weld strength. In addition, the arc welding apparatus 1 allows easy visual inspection of whether the first base material 80 and the second base material 90 have been satisfactorily welded. Therefore, the arc welding apparatus 1 can easily ensure the required welding quality.

[0050] For these reasons, the arc welding device 1 of this embodiment can weld together base materials 80, 90 having different thicknesses or shapes with high quality in a small working space.

[0051] Furthermore, the arc welding apparatus 1 of this embodiment is equipped with a pressing mechanism 40 that is connected to the first earth electrode 20 and the second earth electrode 30 and presses the first earth electrode 20 and the second earth electrode 30 against the flat portion 81 of the first base material 80 and the flat portion 91 of the second base material 90, respectively, with different loads.

[0052] As a result, even if the rigidity of the first base material 80 and the second base material 90 differs due to differences in plate thickness, shape, etc., of the first base material 80 and the second base material 90, the arc welding apparatus 1 can appropriately press the first earth electrode 20 and the second earth electrode 30 against the flat portions 81, 91 in accordance with the rigidity of the first base material 80 and the second base material 90. Therefore, the arc welding apparatus 1 can reliably bring the first earth electrode 20 and the second earth electrode 30 into contact with the flat portions 81, 91 and prevent excessive deformation of one of the first base material 80 and the second base material 90. Therefore, the arc welding apparatus 1 can prevent deterioration of welding quality due to poor earth grounding, such as when the welding current does not flow stably and the arc discharge becomes unstable, or when the bent portions 82, 92 cannot maintain a posture suitable for welding. In addition, the arc welding apparatus 1 can prevent the first base material 80 and the second base material 90 from being excessively deformed, thereby reliably easing restrictions on the shape or material of the first base material 80 and the second base material 90. Therefore, the arc welding apparatus 1 of this embodiment can weld base materials 80, 90 having different thicknesses or shapes with high quality in a small working space.

[0053] Furthermore, in the arc welding apparatus 1 of this embodiment, the flat portion 81 of the first base material 80 and the flat portion 91 of the second base material 90 have different heights from the reference plane, and the pressing mechanism 40 is connected to the first earth electrode 20 and the second earth electrode 30 and is equipped with an absorption mechanism 50 that absorbs the difference in height between the flat portions 81, 91 of the first base material 80 and the second base material 90.

[0054] As a result, the arc welding apparatus 1 can reliably bring the first earth electrode 20 and the second earth electrode 30 into contact with the flat portions 81, 91 even if the heights of the flat portions 81, 91 are different due to design differences or variations in assembly tolerances of the power conversion device 100 or the like. Therefore, the arc welding apparatus 1 can prevent a deterioration in welding quality caused by an unstable arc discharge due to an insufficient earth grounding, which prevents a stable flow of welding current. Therefore, the arc welding apparatus 1 of this embodiment can weld base materials 80, 90 having different thicknesses or shapes with high quality in a small working space.

[0055] Furthermore, in the arc welding apparatus 1 of this embodiment, the pressing mechanism 40 is equipped with a load detector 60 that detects the pressing load of the first earth electrode 20 against the flat portion 81 of the first base material 80 and the pressing load of the second earth electrode 30 against the flat portion 91 of the second base material 90.

[0056] This allows the arc welding apparatus 1 to monitor whether there is poor contact between the first earth electrode 20 and the second earth electrode and the flat portions 81, 91. Therefore, the arc welding apparatus 1 can prevent a decrease in welding quality caused by poor earth grounding due to poor contact between the first earth electrode 20 and the second earth electrode 30. Therefore, the arc welding apparatus 1 of this embodiment can weld base materials 80, 90 having different thicknesses or shapes with high quality in a small working space.

[0057] Furthermore, in the arc welding apparatus 1 of this embodiment, the pressing mechanism 40 is provided with a load adjustment mechanism 70 that adjusts the pressing load of the first earth electrode 20 against the flat portion 81 of the first base material 80 and the pressing load of the second earth electrode 30 against the flat portion 91 of the second base material 90.

[0058] As a result, the arc welding apparatus 1 can prevent poor earth grounding and perform stable arc discharge, and can reliably maintain the posture of each bent portion 82, 92 suitable for welding, thereby ensuring the required welding quality. In addition, the arc welding apparatus 1 suppresses excessive deformation of the first base metal 80 and the second base metal 90, and can reliably alleviate restrictions on the shape or material of the first base metal 80 and the second base metal 90. Therefore, the arc welding apparatus 1 of this embodiment can weld base metals 80, 90 having different thicknesses, shapes, etc. with high quality in a narrow working space.

[0059] Furthermore, in the arc welding apparatus 1 of this embodiment, the first earth electrode 20 has a width dimension intersecting both the extension direction and the thickness direction of the first earth electrode 20 that is larger than the width dimension of the welding electrode 11. The second earth electrode 30 has a width dimension intersecting both the extension direction and the thickness direction of the second earth electrode 30 that is larger than the width dimension of the welding electrode 11. The first earth electrode 20 and the second earth electrode 30 surround the welding electrode 11.

[0060] As a result, the first earth electrode 20 and the second earth electrode 30 can shield the heat and light generated by the arc discharge even in a small work space. Therefore, the arc welding apparatus 1 does not require the separate installation of a burn prevention member, which was previously required, and can prevent heat burning of surrounding components even in a small work space. Therefore, the arc welding apparatus 1 of this embodiment can weld base materials 80, 90 having different thicknesses or shapes with high quality in a small work space while preventing heat burning of surrounding components.

[0061] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0062] 1... arc welding device, 11... welding electrode, 20... first earth electrode, 30... second earth electrode, 40... pressing mechanism, 50... absorbing mechanism, 60... load detector, 70... load adjusting mechanism, 80... first base material, 81... flat portion, 82... bent portion, 90... second base material, 91... flat portion, 92... bent portion

Claims

1. An arc welding device for welding a first base metal and a second base metal, each of which has a flat portion and a bent portion, the flat portions extending in directions approaching each other, and the bent portions bending from the flat portions to extend in a direction intersecting the flat portions and abut against each other, a welding electrode disposed opposite to a contact portion between the bent portion of the first base material and the bent portion of the second base material; a first earth electrode extending along the bent portion of the first base material and abutting the flat portion of the first base material; a second earth electrode extending along the bent portion of the second base material and abutting on the flat portion of the second base material, The first earth electrode and the second earth electrode are in contact with the flat portion of the first base material and the flat portion of the second base material, respectively, independently of each other.

1. An arc welding device characterized by:

2. a pressing mechanism connected to the first earth electrode and the second earth electrode, which presses the first earth electrode and the second earth electrode against the flat portion of the first base material and the flat portion of the second base material, respectively, with different loads.

2. The arc welding device according to claim 1.

3. the flat portion of the first base material and the flat portion of the second base material have different heights from a reference plane, The pressing mechanism includes an absorption mechanism that absorbs the difference in height between the flat portions of the first base material and the second base material.

3. The arc welding device according to claim 2.

4. The pressing mechanism includes a load detector that detects a pressing load of the first earth electrode against the flat portion of the first base material and a pressing load of the second earth electrode against the flat portion of the second base material.

3. The arc welding device according to claim 2.

5. The pressing mechanism includes a load adjusting mechanism that adjusts a pressing load of the first earth electrode against the flat portion of the first base material and a pressing load of the second earth electrode against the flat portion of the second base material.

3. The arc welding device according to claim 2.

6. a dimension of the first earth electrode in a width direction intersecting both an extension direction and a plate thickness direction of the first earth electrode is larger than a dimension of the welding electrode in the width direction; a dimension of the second earth electrode in a width direction intersecting both an extension direction and a plate thickness direction of the second earth electrode is larger than a dimension of the welding electrode in the width direction; The first and second ground electrodes surround the welding electrode.

2. The arc welding device according to claim 1.

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