Joining structure

Abstract

A third member 30 comprises a laminated part 31, a first joining part 32 and a second joining part 33. The laminated part 31 is solidified inside a penetration part 11 and extends in the lamination direction. The first joining part 32 is integrally provided with the laminated part 31, and is joined to a first plating layer 15a and a second member 20. The second joining part 33 is integrally provided with the laminated part 31 and is joined to a second plating layer 15b.

Description

Joint structure

[0001] The present invention relates to a joint structure.

[0002] Patent Document 1 discloses a joining structure in which a first member (first metal material) and a second member (dissimilar material) that is difficult to weld to the first member are overlapped, and a third member (third material) is melted and arc-welded through a penetration portion of the second member.

[0003] At this time, the molten third member forms a flange portion that covers the outer periphery of the upper surface of the penetration portion of the second member, thereby fixing the first member and the second member together by the compressive fixing force between the flange portion and the first member due to solidification and shrinkage of the third member relative to the first member.

[0004] International Publication No. 2018 / 030272

[0005] However, in the invention of Patent Document 1, there is a risk that moisture may enter from the outside through the gap between the overlapping surfaces of the flange portion of the third member and the second member and the gap between the overlapping surfaces of the first member and the second member. The moisture may then cause electrolytic corrosion in the overlapping portion between the flange portion of the third member and the second member and the overlapping portion between the first member and the second member, which may reduce the joining strength.

[0006] The aspects of the present disclosure have been made in consideration of these points, and their purpose is to suppress the occurrence of electrolytic corrosion in the overlapping portions of the first member, the second member, and the third member.

[0007] A first aspect is a joining structure in which a first member made of a metallic material, a second member made of a material that is difficult to weld to the first member and laminated on the first member, and a third member made of a filler metal of the same type as the second member are joined together, wherein a plating layer made of the same type of material as the second member is provided on a surface of the first member, the plating layer including a first plating layer provided on a surface of the first member facing the second member and a second plating layer provided on a surface of the first member opposite to the first plating layer, the first member is provided with a through portion that penetrates in the stacking direction, and the third member has a stacking portion that solidifies inside the through portion and extends in the stacking direction, a first joining portion that is formed integrally with the stacking portion and joined to the first plating layer and the second member, and a second joining portion that is formed integrally with the stacking portion and joined to the second plating layer.

[0008] In the first aspect, a plating layer made of the same material as the second member is provided on the surface of the first member, so that the overlapping portion between the first member and the second member is made of the same material. Also, the joint portion between the first joint portion of the third member and the first plating layer and the second member, and the joint portion between the second joint portion and the second plating layer are also made of the same material.

[0009] In this way, by eliminating the areas where the metal material and the dissimilar material directly overlap in the overlapping portions of the first member, the second member, and the third member, it is possible to suppress the occurrence of electrolytic corrosion and ensure the joining strength.

[0010] Furthermore, by compressing and fixing the first member and the second member using the first joint and the second joint, the overlapping portions of the first member and the second member are tightly adhered to each other, making it difficult for moisture to penetrate from the outside.

[0011] Furthermore, even if the inner peripheral surface of the through-hole is not provided with a plating layer and the first member is exposed from the through-hole, by joining the first bonding portion to the first plating layer and the second bonding portion to the second plating layer, it is possible to prevent moisture from penetrating from the outside toward the inner peripheral surface of the through-hole, thereby preventing electrolytic corrosion from occurring on the inner peripheral surface of the through-hole in the first member and ensuring bonding strength.

[0012] In a second aspect, in the joining structure of the first aspect, the second member is provided with a recess that is recessed in the stacking direction at a position corresponding to the through portion, and the periphery of the recess is located outside the periphery of the through portion when viewed from the stacking direction.

[0013] In the second aspect, when the molten third member is caused to flow from the through-hole toward the recess, the third member spreads outward beyond the through-hole, making it easier to join the first joining portion of the third member to the first plating layer.

[0014] In a third aspect, in the joining structure of the second aspect, the distance between the periphery of the recess and the periphery of the through portion is at least 0.5 mm or more.

[0015] In the third aspect, by appropriately setting the distance between the periphery of the recess and the periphery of the through-hole, it becomes easier to join the first joining portion of the third member to the first plating layer.

[0016] A fourth aspect is the joining structure of any one of the first to third aspects, wherein the through portion is formed in a circular shape, and the hole diameter of the through portion is φ7 mm or more.

[0017] In the fourth aspect, by forming the through-hole into a circular shape and appropriately setting the hole diameter of the through-hole, it becomes easy to insert the third member as a filler metal through the through-hole. Also, the joining area between the second member and the third member can be increased, and the joining strength can be ensured.

[0018] A fifth aspect is the joining structure of any one of the first to third aspects, wherein the through portion is formed in a rectangular shape, and the length of the short side of the through portion is 7 mm or more.

[0019] In the fifth aspect, by forming the through-hole into a rectangular shape and appropriately setting the length of the short side of the through-hole, it becomes easy to insert the third member as a filler metal through the through-hole. Also, the joining area between the second member and the third member can be increased, and the joining strength can be ensured.

[0020] A sixth aspect is the joining structure of any one of the first to third aspects, wherein the second member and the plating layer are made of copper or aluminum.

[0021] In a sixth aspect, the second member and the plating layer are made of copper or aluminum, and the first member may be made of, for example, an iron-based metal material.

[0022] In a seventh aspect, in the joint structure of any one of the first to third aspects, a peripheral edge portion of the through portion is formed in a shape that is bent in the stacking direction.

[0023] In the seventh aspect, the bonding area between the third member and the plating layer can be increased by bending the peripheral edge of the through-hole. For example, by forming the through-hole by press working, the peripheral edge of the through-hole can be made to have a bent shape. Also, for example, by forming the through-hole by drilling, the peripheral edge of the through-hole can be made to have a bent shape due to burrs or the like generated on the peripheral edge of the through-hole.

[0024] According to an aspect of the present disclosure, it is possible to suppress the occurrence of electrolytic corrosion in the overlapping portions of the first member, the second member, and the third member.

[0025] FIG. 1 is a perspective view for explaining a joining structure according to the first embodiment. FIG. 2 is a side cross-sectional view for explaining the joining structure. FIG. 3 is a diagram showing the relationship between the inner diameter of a penetration portion and the inner diameter of a recess. FIG. 4 is a side cross-sectional view for explaining a joining structure according to the second embodiment. FIG. 5 is a side cross-sectional view for explaining a joining structure according to the third embodiment. FIG. 6 is a side cross-sectional view for explaining a joining structure according to the fourth embodiment. FIG. 7 is a side cross-sectional view for explaining a joining structure according to the fifth embodiment. FIG. 8 is a side cross-sectional view for explaining a joining structure according to the sixth embodiment. FIG. 9 is a side cross-sectional view for explaining a joining structure according to the seventh embodiment. FIG. 10 is a side cross-sectional view for explaining a joining structure according to the eighth embodiment. FIG. 11 is a side cross-sectional view for explaining a joining structure according to the ninth embodiment. FIG. 12 is a side cross-sectional view for explaining a joining structure according to the tenth embodiment. FIG. 13 is a side cross-sectional view for explaining a joining structure according to the eleventh embodiment. FIG. 14 is a perspective view for explaining a joining structure according to another embodiment.

[0026] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0027] 1 and 2 show a joining structure for joining together a first member 10 made of a metal material, a second member 20 made of a material that is difficult to weld to the first member 10 and laminated on the first member 10, and a third member 30 made of a filler material.

[0028] The first member 10 is a plate-shaped member made of a metal material. A plating layer 15 is provided on the surface of the first member 10. The plating layer 15 is made of the same type of material as the second member 20.

[0029] The plating layer 15 includes a first plating layer 15a and a second plating layer 15b. The first plating layer 15a is provided on the surface of the first member 10 facing the second member 20 (the bottom surface in FIG. 2). The second plating layer 15b is provided on the surface of the first member 10 opposite to the first plating layer 15a (the top surface in FIG. 2).

[0030] The plating layer 15 may also be provided on the outer periphery of the first member 10 so as to cover the entire first member 10. The first member 10 is provided with a through portion 11 that penetrates in the stacking direction. The through portion 11 is a circular through hole.

[0031] The second member 20 is a plate-like member made of a material that is difficult to weld to the first member 10. The second member 20 is placed on the underside of the first member 10. The second member 20 is provided with a recess 21 that is recessed in the stacking direction at a position corresponding to the through-hole 11. The recess 21 is formed in a circular shape. The periphery of the recess 21 is located outside the periphery of the through-hole 11 when viewed from the stacking direction.

[0032] The third member 30 is made of a filler metal that is the same type of metal as the plating layer 15 of the first member 10 and the second member 20. Here, the term "similar metals" refers to metals that can be welded to each other, and not only to metals of the same material, but also to metals that have good weldability, such as ferrous metals and non-ferrous metals. In other words, "similar metals" refers to materials of the same type that are compatible for welding.

[0033] Specifically, the following combinations of the second member 20 and the third member 30 during welding can be cited. For example, combinations of ferrous metal materials include mild steel and mild steel, stainless steel and stainless steel, and mild steel and high-tensile steel (high-tensile steel). Furthermore, combinations of non-ferrous metal materials include aluminum and aluminum, aluminum and aluminum alloy, aluminum alloy and aluminum alloy, copper and copper, copper and copper alloy, and copper alloy and copper alloy.

[0034] Furthermore, the second member 20 as a different material is made of a material different from that of the first member 10 and is difficult to weld to the first member 10 .

[0035] For example, if the first member 10 as a metal material is an iron-based metal material, the second member 20 as a different material is a non-ferrous metal material such as copper or aluminum.

[0036] The third member 30 has a lamination portion 31, a first joint portion 32, and a second joint portion 33. The lamination portion 31 is formed by solidifying a molten filler material inside the through portion 11. The lamination portion 31 extends inside the through portion 11 in the lamination direction.

[0037] The first bonding portion 32 is provided integrally with the lower end portion in the stacking direction of the laminated portion 31. The first bonding portion 32 protrudes outward beyond the through-hole 11. The first bonding portion 32 is bonded to the first plating layer 15a and the second member 20. Specifically, the first bonding portion 32 is welded to the peripheral edge of the through-hole 11 in the first plating layer 15a of the first member 10 and to the second member 20.

[0038] The second bonding portion 33 is integral with the upper end portion of the laminated portion 31 in the stacking direction. The second bonding portion 33 protrudes outward beyond the through-hole 11. The second bonding portion 33 is bonded to the second plating layer 15b. Specifically, the second bonding portion 33 is welded to the periphery of the through-hole 11 in the second plating layer 15b of the first member 10.

[0039] When the third member 30 solidifies and shrinks, the first joint 32 pulls the second member 20 upward, and the second joint 33 presses the first member 10 downward, thereby compressing and fixing the first member 10 and the second member 20.

[0040] <Joining Method> Next, a description will be given of a joining method for joining the first member 10, the second member 20, and the third member 30. In the following description, a case will be described in which a mild steel material is used as the first member 10, an aluminum plating is used as the plating layer 15 of the first member 10, an aluminum material is used as the second member 20, and an aluminum material is used as the third member 30, which is a filler metal.

[0041] Although the case where aluminum plating is used as the plating layer 15 of the first member 10, aluminum material is used as the second member 20, and aluminum material is used as the third member 30 which is a filler metal, copper may be used instead of aluminum. Specifically, this is the case where copper plating is used as the plating layer 15 of the first member 10, copper material is used as the second member 20, and copper material is used as the third member 30 which is a filler metal.

[0042] 2, the arc welding machine 1 includes a nozzle 2 and a tip 3. The nozzle 2 supplies a shielding gas or the like to a welding point of an object to be welded. The tip 3 supplies a welding current to a third member 30 serving as a filler metal.

[0043] First, the first member 10 is stacked on the upper surface of the second member 20. At this time, the second member 20 is arranged so that the surface on the opening side of the recess 21 abuts against the first member 10. At this time, the through portion 11 of the first member 10 and the recess 21 of the second member 20 are arranged approximately concentrically when viewed from the stacking direction.

[0044] The arc welding machine 1 generates an arc 5 by supplying a welding current while feeding a third member 30 , which is a filler material of the same type as the second member 20 .

[0045] The third member 30 melted by arc welding is filled into the recess 21 through the through-hole 11. In the recess 21, the molten third member 30 flows outward from the through-hole 11 and spreads in a flange shape.

[0046] The molten third member 30 fills the recess 21 completely, and then fills the inside of the through-hole 11 and is laminated therein. Then, after filling the inside of the through-hole 11 completely, the molten third member 30 flows outward from the peripheral edge of the through-hole 11 and spreads in a flange shape.

[0047] Then, as the molten metal solidifies and shrinks, a third member 30 is formed, which has a laminated portion 31, a first joint portion 32 formed integrally with the laminated portion 31, and a second joint portion 33 formed integrally with the laminated portion 31.

[0048] The first bonding portion 32 is filled in the recess 21 and thereby bonded to the second member 20. Furthermore, the first bonding portion 32 protrudes outward beyond the through-hole 11 within the recess 21 of the second member 20 and is bonded to the peripheral portion of the through-hole 11 in the first plating layer 15a.

[0049] The second bonding portion 33 protrudes outward beyond the peripheral edge of the through portion 11 and is bonded to the peripheral edge of the through portion 11 in the second plating layer 15b.

[0050] <Relationship between Inner Diameter of Penetration Portion and Inner Diameter of Recess> The relationship between the inner diameter of the penetration portion 11 of the first member 10 and the inner diameter of the recess 21 of the second member 20 will be described below with reference to Fig. 3. The wire diameter of the third member 30 as a filler metal is set to φ1.2 mm.

[0051] As shown in Figure 3, when the inner diameter of the through-hole 11 of the first member 10 is φ6 mm, even when the inner diameter of the recess 21 of the second member 20 is changed within the range of φ6 to φ10 mm, the molten third member 30 does not sufficiently fill the through-hole 11 of the first member 10. In Figure 3, a welding state in which the filler material is not sufficiently filled is indicated by "△". Therefore, it is preferable that the inner diameter of the through-hole 11 of the first member 10 be φ7 mm or more.

[0052] Furthermore, when the inner diameter of the through portion 11 of the first member 10 is φ7 mm and the inner diameter of the recess 21 of the second member 20 is set to φ7 mm, the first joint portion 32 and the second joint portion 33 of the third member 30 do not protrude radially outward along the peripheral edge of the through portion 11. In Figure 3, a welding state in which the second joint portion 33 does not protrude radially outward beyond the peripheral edge of the through portion 11 is indicated by an "x". Furthermore, a welding state in which the second joint portion 33 protrudes radially outward beyond the peripheral edge of the through portion 11 is indicated by an "o".

[0053] Here, when the inner diameter of the through-hole 11 of the first member 10 is φ8 mm, if the inner diameter of the recess 21 of the second member 20 is set to φ7 mm or φ8 mm, the welding condition will be "×". On the other hand, if the inner diameter of the recess 21 of the second member 20 is set to φ9 mm or φ10 mm, the welding condition will be "◯".

[0054] Furthermore, when the inner diameter of the through-hole 11 of the first member 10 is φ9 mm, if the inner diameter of the recess 21 of the second member 20 is changed within the range of φ7 to φ9 mm, the welding condition becomes "X". On the other hand, if the inner diameter of the recess 21 of the second member 20 is set to φ10 mm, the welding condition becomes "O".

[0055] That is, the inner diameter of the recess 21 of the second member 20 needs to be larger than the inner diameter of the through-hole 11 of the first member 10. For example, it is preferable that the distance between the periphery of the recess 21 and the periphery of the through-hole 11 is at least 0.5 mm or more.

[0056] In this way, by appropriately setting the inner diameter of the through portion 11 and the inner diameter of the recess 21 in the second member 20, it is possible to sufficiently fill the molten third member 30 into the recess 21. This makes it possible to form the first bonding portion 32 and the second bonding portion 33 with appropriate shapes.

[0057] -Effects of this embodiment- As described above, according to the joining structure of this embodiment, by eliminating the overlapping portions of the metal material and the dissimilar material at the overlapping portions of the first member 10, the second member 20, and the third member 30, it is possible to suppress the occurrence of electrolytic corrosion and ensure joining strength.

[0058] Furthermore, by compressing and fixing the first member 10 and the second member 20 together using the first joint 32 and the second joint 33, the overlapping portions of the first member 10 and the second member 20 are tightly attached, making it difficult for moisture to penetrate from the outside.

[0059] Here, if the plating layer 15 is not provided on the inner peripheral surface of the through-hole 11 and the first member 10 is exposed from the through-hole 11, the laminated portion 31 arranged in the through-hole 11 is in contact with the first member 10. Furthermore, cracks may occur in the laminated portion 31 due to differences in the thermal contraction speed between the first member 10 and the third member 30 when the third member 30 solidifies, or due to changes over time. Furthermore, if moisture penetrates into the gap between the through-hole 11 and the laminated portion 31, an intermetallic compound may be generated.

[0060] In contrast, in the present embodiment, by joining the first bonding portion 32 to the first plating layer 15a and the second bonding portion 33 to the second plating layer 15b, it is possible to prevent moisture from penetrating from the outside toward the inner circumferential surface of the through portion 11. This makes it possible to prevent electrolytic corrosion from occurring on the inner circumferential surface of the through portion 11 in the first member 10 and ensure bonding strength.

[0061] Furthermore, when the molten third member 30 is caused to flow from the through-hole 11 toward the recess 21, the third member 30 spreads outward beyond the through-hole 11, making it easier to bond the first bonding portion 32 of the third member 30 to the first plating layer 15a. Also, a wide first bonding portion 32 can be formed.

[0062] Furthermore, by melt-joining materials of the same type, it is possible to prevent the intrusion of moisture from the outside and to suppress electrolytic corrosion without using different construction methods such as commonly used adhesives, sealants, and sealing agents.

[0063] Second Embodiment Hereinafter, the same parts as those in the first embodiment will be denoted by the same reference numerals, and only the differences will be described.

[0064] 4 , the second member 20 is provided with a recess 21 recessed in the stacking direction at a position corresponding to the through-hole 11. The recess 21 has an inclined portion 25 inclined toward the bottom of the recess 21. The opening width of the recess 21 is larger than the inner diameter of the through-hole 11.

[0065] The third member 30 is melted by arc welding. The molten third member 30 flows along the inclined portion 25 of the recess 21 and is joined to the second member 20. Inside the recess 21, the molten third member 30 spreads so as to protrude radially outward beyond the through portion 11, and the first joining portion 32 is joined to the first plating layer 15a.

[0066] Furthermore, the molten third member 30 fills up the inside of the through-hole 11, spreading in a flange shape onto the upper surface of the first member 10, and the second bonding portion 33 is bonded to the second plating layer 15b.

[0067] As described above, according to the joining structure of this embodiment, the provision of the inclined portion 25 in the recess 21 makes it easier for the molten third member 30 to flow toward the bottom of the recess 21 .

[0068] 5 , the second member 20 is provided with a recess 21 recessed in the stacking direction at a position corresponding to the through-hole 11. The recess 21 has a step portion 26 formed in a circular shape when viewed from the stacking direction, and an inclined portion 25 inclined from the step portion 26 toward the bottom of the recess 21. The opening width of the recess 21 is larger than the inner diameter of the through-hole 11.

[0069] The third member 30 is melted by arc welding. The molten third member 30 flows along the inclined portion 25 of the recess 21 and is joined to the second member 20. Inside the recess 21, the molten third member 30 fills the inclined portion 25 and the stepped portion 26, spreading radially outward beyond the through portion 11, and the first joining portion 32 is joined to the first plating layer 15a.

[0070] Furthermore, the molten third member 30 fills up the inside of the through-hole 11, spreading in a flange shape onto the upper surface of the first member 10, and the second bonding portion 33 is bonded to the second plating layer 15b.

[0071] As described above, according to the joining structure of this embodiment, by providing an inclined portion 25 and a step portion 26 in the recess 21, the joining area of ​​the third member 30 can be increased compared to when the bottom of the recess 21 is only a flat surface.

[0072] 6 , the second member 20 is provided with a recess 21 recessed in the stacking direction at a position corresponding to the through-hole 11. The recess 21 has a step portion 26 formed in a circular shape when viewed from the stacking direction, a flat portion 27 provided at the bottom of the recess 21, and an inclined portion 25 inclined from the step portion 26 toward the flat portion 27. The opening width of the recess 21 is larger than the inner diameter of the through-hole 11.

[0073] The third member 30 is melted by arc welding. The molten third member 30 flows along the inclined portion 25 of the recess 21 toward the flat portion 27 and is joined to the second member 20. Inside the recess 21, the molten third member 30 fills the inclined portion 25, the step portion 26, and the flat portion 27, spreading so as to protrude radially outward beyond the through portion 11, and the first joining portion 32 is joined to the first plating layer 15a.

[0074] Furthermore, the molten third member 30 fills up the inside of the through-hole 11, spreading in a flange shape onto the upper surface of the first member 10, and the second bonding portion 33 is bonded to the second plating layer 15b.

[0075] As described above, according to the joining structure of this embodiment, by providing the recess 21 with an inclined portion 25, a step portion 26, and a flat portion 27, the joining area of ​​the third member 30 can be increased compared to when the bottom of the recess 21 is only a flat surface.

[0076] 7, the first member 10 has a through portion 11. The through portion 11 has a tapered portion 12 that tapers toward the second member 20. The taper angle of the tapered portion 12 is preferably set in the range of 30° to 120°, for example.

[0077] The second member 20 is provided with a recess 21 recessed in the stacking direction at a position corresponding to the through-hole 11. The recess 21 is formed in a circular shape when viewed from the stacking direction. The opening width of the recess 21 is larger than the inner diameter of the through-hole 11 on the second member 20 side.

[0078] The third member 30 is melted by arc welding. The molten third member 30 flows along the tapered portion 12 of the through portion 11 so as to gather at the center of the through portion 11.

[0079] As described above, the joining structure according to this embodiment allows the molten third member 30 to easily flow toward the center of the through-hole 11. Furthermore, by increasing the width of the second joining portion 33, the joining area with the second plating layer 15b can be increased, and the joining strength can be ensured.

[0080] 8, the first member 10 has a through portion 11. The through portion 11 has a tapered portion 12 that tapers toward the side opposite to the second member 20. The taper angle of the tapered portion 12 is preferably set in the range of 30° to 120°, for example.

[0081] The second member 20 is provided with a recess 21 recessed in the stacking direction at a position corresponding to the through-hole 11. The recess 21 is formed in a circular shape when viewed from the stacking direction. The opening width of the recess 21 is larger than the inner diameter of the through-hole 11 on the second member 20 side.

[0082] The third member 30 is melted by arc welding. The molten third member 30 fills the recess 21 and is joined to the second member 20. The molten third member 30 fills the inside of the recess 21, and spreads to protrude radially outward beyond the through-hole 11, and the first joining portion 32 is joined to the first plating layer 15a.

[0083] Furthermore, the molten third member 30 fills up the inside of the through-hole 11, spreading in a flange shape onto the upper surface of the first member 10, and the second bonding portion 33 is bonded to the second plating layer 15b.

[0084] As described above, the joining structure according to this embodiment allows the molten third member 30 to flow along the tapered portion 12 of the through portion 11 to the corners of the recess 21. Furthermore, by increasing the width of the first joining portion 32, the joining area with the second member 20 can be increased, and the joining strength can be ensured.

[0085] Furthermore, with this joining structure, for example, when the arrangement of the first member 10 and the second member 20 shown in Figure 8 is rotated 90 degrees, that is, when arc welding is performed horizontally on the first member 10 and the second member 20 that are arranged in a vertical position, the molten third member 30 filled in the through portion 11 is less likely to drip to the outside.

[0086] 9 , the second member 20 is provided with a recess 21 recessed in the stacking direction at a position corresponding to the through-hole 11. The recess 21 is formed by press-forming a part of the second member 20 so that it bulges out on the side opposite to the first member 10. The opening width of the recess 21 is larger than the inner diameter of the through-hole 11 on the second member 20 side.

[0087] The third member 30 is melted by arc welding. The molten third member 30 fills the recess 21 and is joined to the second member 20. The molten third member 30 fills the inside of the recess 21, and spreads to protrude radially outward beyond the through-hole 11, and the first joining portion 32 is joined to the first plating layer 15a.

[0088] Furthermore, the molten third member 30 fills up the inside of the through-hole 11, spreading in a flange shape onto the upper surface of the first member 10, and the second bonding portion 33 is bonded to the second plating layer 15b.

[0089] As described above, according to the joining structure of this embodiment, a recess 21 can be provided in the second member 20 while maintaining the plate thickness of the second member 20 constant, thereby ensuring the rigidity of the second member 20.

[0090] Eighth Embodiment As shown in Fig. 10 , the first member 10 has a through-hole 11. The peripheral portion of the through-hole 11 is formed in a shape that is bent in the stacking direction. In the example shown in Fig. 10 , the peripheral portion of the through-hole 11 is bent in a convex shape toward the side opposite the second member 20 (the upper side in Fig. 10 ). In Fig. 10 , the peripheral portion of the through-hole 11 is bent at 45° with respect to the lower surface of the first member 10, but it may also be bent at an angle in the range of 15° to 60°, for example.

[0091] Here, for example, by forming the through-hole 11 by press working, it is possible to form a curved shape at the peripheral portion of the through-hole 11. Also, for example, by forming the through-hole 11 by drilling using a drill, it is possible to form a curved shape at the peripheral portion of the through-hole 11 due to burrs or the like generated on the peripheral portion of the through-hole 11.

[0092] The third member 30 is melted by arc welding. The melted third member 30 fills the space partitioned by the bent portion of the periphery of the through portion 11 in the first member 10 and the second member 20, and is joined to the second member 20. The melted third member 30 fills the space partitioned by the bent portion of the periphery of the through portion 11 in the first member 10 and the second member 20, and spreads to protrude radially outward beyond the through portion 11, and the first joint portion 32 is joined to the first plating layer 15a.

[0093] Furthermore, the molten third member 30 fills up the inside of the through-hole 11, spreading in a flange shape onto the upper surface of the first member 10, and the second bonding portion 33 is bonded to the second plating layer 15b.

[0094] As described above, according to the joining structure of this embodiment, by bending the peripheral edge portion of the through portion 11, the joining area between the third member 30 and the plating layer 15 can be increased.

[0095] Ninth Embodiment As shown in Fig. 11 , the first member 10 has a through-hole 11. The peripheral portion of the through-hole 11 is formed in a shape that is bent in the stacking direction. In the example shown in Fig. 11 , the peripheral portion of the through-hole 11 is bent in a convex shape toward the side opposite the second member 20 (the upper side in Fig. 11 ). In Fig. 11 , the peripheral portion of the through-hole 11 is bent at 90° with respect to the lower surface of the first member 10.

[0096] The third member 30 is melted by arc welding. The melted third member 30 fills the space partitioned by the bent portion of the periphery of the through portion 11 in the first member 10 and the second member 20, and is joined to the second member 20. The melted third member 30 fills the space partitioned by the bent portion of the periphery of the through portion 11 in the first member 10 and the second member 20, and spreads to protrude radially outward beyond the through portion 11, and the first joint portion 32 is joined to the first plating layer 15a.

[0097] Furthermore, the molten third member 30 fills up the inside of the through-hole 11, spreading in a flange shape onto the upper surface of the first member 10, and the second bonding portion 33 is bonded to the second plating layer 15b.

[0098] As described above, according to the joining structure of this embodiment, by bending the peripheral edge portion of the through portion 11, the joining area between the third member 30 and the plating layer 15 can be increased.

[0099] Tenth Embodiment As shown in Fig. 12 , the first member 10 has a through-hole 11. The peripheral portion of the through-hole 11 is formed in a shape that is bent in the stacking direction. In the example shown in Fig. 12 , the peripheral portion of the through-hole 11 is bent in a convex shape toward the side facing the second member 20 (the lower side in Fig. 12 ). In Fig. 12 , the peripheral portion of the through-hole 11 is bent at 45° with respect to the upper surface of the first member 10, but it may also be bent at an angle in the range of 15° to 60°, for example.

[0100] The second member 20 is provided with a recess 21 recessed in the stacking direction at a position corresponding to the through portion 11. The recess 21 is formed in a circular shape when viewed in the stacking direction. The recess 21 accommodates a part of the bent portion of the periphery of the through portion 11 in the first member 10. The opening width of the recess 21 is larger than the inner diameter of the through portion 11.

[0101] The third member 30 is melted by arc welding. The molten third member 30 fills the recess 21 and is joined to the second member 20. Inside the recess 21, the molten third member 30 spreads so as to protrude radially outward beyond the through-hole 11, and the first joining portion 32 is joined to the first plating layer 15a.

[0102] Furthermore, the molten third member 30 fills up the inside of the through-hole 11, spreading in a flange shape onto the upper surface of the first member 10, and the second bonding portion 33 is bonded to the second plating layer 15b.

[0103] As described above, according to the joining structure of this embodiment, by bending the peripheral edge portion of the through portion 11, the joining area between the third member 30 and the plating layer 15 can be increased.

[0104] Eleventh Embodiment As shown in Fig. 13 , the first member 10 has a through-hole 11. The peripheral portion of the through-hole 11 is formed in a shape that is bent in the stacking direction. In the example shown in Fig. 13 , the peripheral portion of the through-hole 11 is bent in a convex shape toward the side facing the second member 20 (the lower side in Fig. 13 ). In Fig. 13 , the peripheral portion of the through-hole 11 is bent at 90° with respect to the upper surface of the first member 10.

[0105] The second member 20 is provided with a recess 21 recessed in the stacking direction at a position corresponding to the through portion 11. The recess 21 is formed in a circular shape when viewed in the stacking direction. The recess 21 accommodates a part of the bent portion of the periphery of the through portion 11 in the first member 10. The opening width of the recess 21 is larger than the inner diameter of the through portion 11.

[0106] The third member 30 is melted by arc welding. The molten third member 30 fills the recess 21 and is joined to the second member 20. Inside the recess 21, the molten third member 30 spreads so as to protrude radially outward beyond the through-hole 11, and the first joining portion 32 is joined to the first plating layer 15a.

[0107] Furthermore, the molten third member 30 fills up the inside of the through-hole 11, spreading in a flange shape onto the upper surface of the first member 10, and the second bonding portion 33 is bonded to the second plating layer 15b.

[0108] As described above, according to the joining structure of this embodiment, by bending the peripheral edge portion of the through portion 11, the joining area between the third member 30 and the plating layer 15 can be increased.

[0109] Other Embodiments The above-described embodiment may be configured as follows.

[0110] In this embodiment, the through portion 11 of the first member 10 is a circular through hole, and during arc welding, the welding point as the welding location is stopped and the third member 30 is fed toward the through portion 11 as a filler material, but this is not limited to this form.

[0111] For example, as shown in FIG. 14 , the through portion 11 of the first member 10 may be a rectangular through hole, and during arc welding, the welding point may be moved from one end of the through portion 11 to the other end in the longitudinal direction while the third member 30 as a filler metal is fed toward the through portion 11.

[0112] Here, the length of the short side of the through-hole 11 is preferably 7 mm or more. This makes it easier to insert the third member 30, which serves as a filler metal, through the through-hole 11. In addition, the joining area between the second member 20 and the third member 30 can be increased, ensuring joining strength.

[0113] As described above, the present invention has the highly practical effect of being able to suppress the occurrence of electrolytic corrosion in the overlapping portions of the first member, the second member, and the third member, and is therefore extremely useful and has high industrial applicability.

[0114] REFERENCE SIGNS LIST 10 First member 11 Penetration portion 15 Plated layer 15a First plated layer 15b Second plated layer 20 Second member 21 Recess 30 Third member 31 Laminated portion 32 First bonding portion 33 Second bonding portion

Claims

1. A joining structure in which a first member made of a metallic material, a second member made of a material that is difficult to weld to the first member and laminated on the first member, and a third member made of a filler metal of the same type as the second member are joined together, wherein a plated layer made of the same type of material as the second member is formed on the surface of the first member, the plated layer including a first plated layer formed on the surface of the first member facing the second member and a second plated layer formed on the surface of the first member opposite the first plated layer, the first member has a through portion that penetrates in the lamination direction, and the third member has: a lamination portion that solidifies inside the through portion and extends in the lamination direction, a first bonding portion that is formed integrally with the lamination portion and bonded to the first plated layer and the second member, and a second bonding portion that is formed integrally with the lamination portion and bonded to the second plated layer.

2. A joining structure according to claim 1, wherein the second member is provided with a recess recessed in the stacking direction at a position corresponding to the through-hole, and the periphery of the recess is located outside the periphery of the through-hole when viewed from the stacking direction.

3. A joining structure according to claim 2, wherein the distance between the periphery of the recess and the periphery of the through-hole is at least 0.5 mm.

4. A joining structure according to any one of claims 1 to 3, wherein the through-hole is formed in a circular shape, and the hole diameter of the through-hole is φ7 mm or more.

5. A joining structure according to any one of claims 1 to 3, wherein the through-hole is formed in a rectangular shape, and the length of the short side of the through-hole is 7 mm or more.

6. The joining structure according to any one of claims 1 to 3, wherein the second member and the plating layer are made of copper or aluminum.

7. A joining structure according to any one of claims 1 to 3, wherein the peripheral edge of the penetration part is formed in a shape bent in the stacking direction.

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