JP6345587B2 - Friction stir welding joint structure and structure including the same - Google Patents

Description

  The present invention relates to a joint structure for friction stir welding and a structure including the joint structure.

  Friction stir welding (Friction) is performed by using a plurality of hollow shapes formed by connecting a pair of plate portions with connecting portions in a state where the plate surfaces are opposed to each other, and abutting the ends of the pair of plate portions of each hollow shape member Friction stir welded bodies joined by stir welding (FSW) are known.

  An example of the friction stir joint is a railway vehicle structure. In a railway vehicle structure, for example, a plurality of hollow shapes are friction stir welded, one plate portion of each hollow shape member forms an outer plate portion facing the outside of the vehicle, and the other plate portion is an inner surface facing the inside of the vehicle. By configuring the plate portion, a double skin structure is formed. This double skin structure makes it possible to reduce the weight and rigidity of the railway vehicle structure.

  Examples of the friction stir welding method include a bobbin tool type friction stir welding method as disclosed in Patent Document 1. In this joining method, for example, a bobbin tool having two large-diameter shoulder portions and a small-diameter stirring shaft (probe) provided therebetween is used. While sandwiching both surfaces of each plate portion of the pair of hollow shapes with the two shoulder portions rotated in a state where the pair of hollow shapes are abutted and fixed, or in a state where the pair of hollow shapes is pressed in the abutting direction, The stirring shaft of the bobbin tool is inserted into the butted portion of the pair of hollow profiles. Then, the pair of hollow profiles are friction stir joined by moving the bobbin tool relative to the pair of hollow profiles along the abutting portion.

Japanese Patent No. 5559214

  When performing friction stir welding of a plurality of hollow shapes, accurate alignment of the hollow shapes is required in order to prevent occurrence of a difference (step difference) in each plate portion of the butted portion. However, alignment may be difficult depending on conditions such as the weight and size of the hollow profile.

  Therefore, the present invention reduces the work load by enabling easy positioning of the hollow shapes when joining a plurality of hollow shapes by the bobbin tool type friction stir welding method. The purpose is to enable good bonding.

  In order to solve the above-described problem, a joint structure for friction stir welding according to an aspect of the present invention includes a first plate portion and a second plate portion that are disposed so that their plate surfaces are spaced apart from each other, A pair of hollow shapes having a connecting portion for connecting the first plate and the second plate in the opposing direction of the first plate and the second plate, the pair of hollow shapes, A joint structure in which the joining end portions of the first plate portion and the joining end portions of the second plate portion are brought into contact with each other and joined by a bobbin tool type friction stir welding method, Each has a fitting part which protrudes from the connection part toward the hollow shape material on the bonding partner side and is fitted to each other, and the joining end parts of the first plate part and the second plate part In order to form a space through which the bobbin tool that joins the joining ends can pass through, The joint portions of the first plate portion are formed by separating the connecting portions of the pair of hollow shapes from each other and separating the fitting portion from the first plate portion and the second plate portion. Between the abutting part between the fitting parts and the fitting part between the fitting parts, and between the abutting part between the joining end parts of the second plate part and the fitting part between the fitting parts, Spaces are formed, and the fitting portions of the pair of hollow shapes are fitted together, whereby the joining end portions of the first plate portion and the joining end portions of the second plate portion Are relatively positioned in the facing direction.

  According to the above configuration, the connecting portions of the pair of hollow profiles are separated from each other, and the fitting portion is separated from the first plate portion and the second plate portion, and the first plate portion and the second plate portion are separated. By forming a space through which the bobbin tool can pass between the joint end portions of the first plate portions and the joint end portions of the second plate portions of the pair of hollow members, respectively, using the bobbin tool Can be joined. In addition, by providing a fitting portion at each connecting portion of the pair of hollow shapes and fitting the fitting portions together, the joint end portion of the first plate portion can be joined when the pair of hollow shapes are friction stir welded. It becomes easy to position each other and the joining end portions of the second plate portion relative to each other in the facing direction. In addition, since the pair of hollow shapes are less likely to be displaced by fitting the fitting portions of the pair of hollow shapes, the first plate portion even if vibration or impact is transmitted to each hollow shape during friction stir welding And the position shift of the joining edge parts of a 2nd board part can be prevented. Therefore, a pair of hollow shapes can be joined by the bobbin tool type friction stir welding method, and friction stir welding can be appropriately performed while reducing the work load.

  According to the present invention, when a plurality of hollow shapes are joined by a bobbin tool type friction stir welding method, the work load is reduced by enabling easy positioning of the hollow shapes, and the hollow shapes are Can be joined well.

It is a partial section perspective view of the railcar structure concerning a 1st embodiment. It is a fragmentary sectional view which shows the joint structure of each hollow shape member which comprises the side structure of FIG. It is sectional drawing explaining the manufacturing procedure of the joint structure of FIG. (A) is a 1st process, (b) is a 2nd process, (c) is a figure which shows a 3rd process, respectively. It is sectional drawing which shows a mode that a pair of hollow shape member of Fig.3 (a) shifts | deviates and approaches. It is a fragmentary sectional view showing the joint structure of each hollow section concerning modification 1 of a 1st embodiment. It is sectional drawing which shows the hollow shape material which concerns on 2nd Embodiment. It is a fragmentary sectional view showing the joint structure of each hollow section concerning a 2nd embodiment. It is a fragmentary sectional view showing a joint structure of each hollow section concerning modification 1 of a 2nd embodiment. It is sectional drawing which shows the joint structure of each hollow shape material which concerns on 3rd Embodiment. It is sectional drawing which shows the joint structure of each hollow shape material which concerns on 4th Embodiment.

  Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In the following description, the “abutting direction” refers to a direction in which joining end portions to be joined are brought close to each other when a pair of hollow shapes are subjected to friction stir welding. The “opposing direction” refers to a direction perpendicular to the opposing plate surfaces of the first plate portion and the second plate portion in the gap G inside each hollow shape member.

(First embodiment)
[Railway vehicle structure]
FIG. 1 is a partial cross-sectional perspective view of a railway vehicle structure 1 according to the first embodiment. FIG. 2 is a partial cross-sectional view showing joint structures 100 and 101 of the hollow members 5 to 8 constituting the side structure 3 of FIG. A railway vehicle structure 1 shown in FIG. 1 is an example of a structure having a joint structure of friction stir welding, and is horizontally arranged with a frame (floor structure) 2 and vertically on both sides in the width direction of the vehicle. A side structure 3 arranged to extend, and a roof structure 4 arranged to be connected to each side structure 3 above each side structure 3 are provided.

  The underframe 2 has a lower plate portion 2a facing the outside of the vehicle, an upper plate portion 2b facing the inside of the vehicle, and a connecting portion 2c that connects the lower plate portion 2a and the upper plate portion 2b with each plate surface. Each side structure 3 has an outer side plate portion 3a facing the outside of the vehicle, an inner side plate portion 3b facing the inside of the vehicle, and a connecting portion 3c for connecting the outer side plate portion 3a and the inner side plate portion 3b with each plate surface. The roof structure 4 includes an outer plate portion 4a facing the outside of the vehicle, an inner plate portion 4b facing the inside of the vehicle, and a connecting portion 4c that connects the outer plate portion 4a and the inner plate portion 4b with each plate surface. The underframe 2, the side structure 3, and the roof structure 4 have a double skin structure in which two plate portions 2a, 2b, 3a, 3b, 4a, and 4b are arranged to face each other with a gap G therebetween. Each of the underframe 2, the side structure 3, and the roof structure 4 is configured by friction stir welding of a plurality of hollow shapes extending in the longitudinal direction of the vehicle.

  The side structure 3 has hollow shapes 5-9. Each of the hollow shapes 5 to 8 is a long member that extends in the longitudinal direction of the vehicle and has a substantially rectangular outline on the plate surface. The hollow member 5 has an opening 3d at a position corresponding to a vehicle window. The hollow shape members 6 to 8 are sequentially arranged downward from the hollow shape member 5. The hollow shape members 6 and 7 have the same configuration. The hollow shape member 8 is disposed at the lower end portion of the side structure 3. The hollow member 9 is disposed at a position opposite to the position of the hollow member 6 with the hollow member 5 interposed therebetween. The hollow shape members 6 to 9 have a flat surface.

[Hollow profile]
Since the basic structures of the hollow members 5 to 9 are substantially the same, the configuration of the hollow member 6 will be mainly described. As shown in FIG. 2, the hollow shape member 6 includes a first plate portion 6a, a second plate portion 6b, connecting portions 6c and 6d, and fitting portions 6e and 6f. Each of the 1st board part 6a and the 2nd board part 6b is a rectangular shape extended in the longitudinal direction of a vehicle, and has a board surface of the same board thickness. As an example, the first plate portion 6a and the second plate portion 6b are arranged with a gap G in a state in which their plate surfaces face each other substantially in parallel. The first plate portion 6 a has a joining end 6 a 1 in the direction toward the hollow shape 7 and has a joining end 6 a 2 in the direction toward the hollow shape 5. The second plate portion 6 b has a joining end portion 6 b 1 in the direction toward the hollow shape member 7 and has a joining end portion 6 b 2 in the direction toward the hollow shape member 5. The end surfaces of the joining end portions 6a2 and 6b2 are located on a straight line Y1 extending in the facing direction. The end surfaces of the joining end portions 6a1 and 6b1 are located on a straight line Y2 extending in the facing direction. Each joining edge part 6a1, 6b1, 6a2, 6b2 has an end surface perpendicular | vertical to a butting direction. The hollow shape member 6 is manufactured by extrusion molding as an example.

  The connecting portions 6c and 6d are plate-like portions extending in the longitudinal direction of the vehicle. The connecting portions 6c and 6d are arranged so as to be orthogonal to the first plate portion 6a and the second plate portion 6b, and connect the first plate portion 6a and the second plate portion 6b. The connecting portions 6c and 6d are arranged in the gap G at positions on the inner side of the hollow shape member 6 with respect to the joining end portions 6a1 and 6b1 and the joining end portions 6a2 and 6b2.

  The fitting portions 6e and 6f are provided in the connecting portions 6c and 6d and protrude toward the butting direction. The fitting portions 6e and 6f protrude in opposite directions along the center line X passing through the center portions R1 and R2 in the opposing direction of the connecting portions 6c and 6d. The fitting portion 6 e protrudes toward the hollow shape member 7, and the fitting portion 6 f protrudes toward the hollow shape member 5. A wedge-shaped male tip 6h extending in the butting direction is formed at the tip of the fitting portion 6f in the protruding direction. A female tip 6g that branches into two and extends in the butting direction is formed at the tip of the fitting portion 6e in the protruding direction. Inside the female tip portion 6g, an internal space S1 that is open in the abutting direction is formed.

  The male tip portion 6h and the female tip portion 6g have inclined surfaces 6h1 and 6g1 that are inclined with respect to the direction in which the center line X extends. The male tip portion 6h and the female tip portion 6g are in contact with the tip portions of the fitting portions of the hollow members 5 and 7 on the mating counterpart side on the inclined surfaces 6h1 and 6g1, respectively. The distal end of the male distal end portion 6h is disposed at a position closer to the hollow shape member 5 than the positions of the joining end portions 6a2 and 6b2 overlapping the straight line Y1. The tip of the female tip 6g is disposed closer to the hollow member 7 than the positions of the joining ends 6a1 and 6b1 overlapping the straight line Y2.

  The hollow shape member 5 includes a first plate portion 5a, a second plate portion 5b, a connection portion (not shown), and a fitting portion 5e. A female tip 5g is formed at the tip of the fitting portion 5e. The hollow shape member 7 has the same structure, shape and size as the hollow shape member 6, and includes a first plate portion 7a, a second plate portion 7b, connecting portions 7c and 7d, and fitting portions 7e and 7f. A male tip 7h is formed at the tip of the fitting portion 7f. A female tip 7g is formed at the tip of the fitting portion 7e. The hollow shape member 8 includes a first plate portion 8a, a second plate portion 8b, a connecting portion 8d, and a fitting portion 8f. A male tip 8h is formed at the tip of the fitting portion 8f.

  In the hollow member 6, the female tip 6g is fitted to the male tip 7h by inserting the male tip 7h of the hollow member 7 into the internal space S1. Further, the male tip portion 6h is inserted into the internal space S1 of the female tip portion 5g of the hollow member 5, so that the male tip portion 6h is fitted with the female tip portion 5g. The contact area where the male tip 6h contacts the female tip 5g on the inclined surface 6h1 partially overlaps the straight line Y1. The contact area where the female tip 6g contacts the male tip 7h on the inclined surface 6g1 partially overlaps the straight line Y2.

  In the side structure 3, in a pair of adjacent hollow shapes among the hollow shapes 5 to 8, the fitting portions (5e and 6f, 6e and 7f, 7e and 8f) are connected to each other (5g). And 6h, 6g and 7h, 7g and 8h) are brought into contact with each other. Thus, in the state where the fitting portions are fitted to each other, each joining end portion of one hollow shape member in the pair of hollow shapes is abutted against each joining end portion of the other hollow shape member, and each joining end The parts (5a1 and 6a2, 5b1 and 6b2, 6a1 and 7a2, 6b1 and 7b2, 7a1 and 8a2, 7b1 and 8b2) are joined by a bobbin tool type friction stir welding. Thereby, in the side structure 3, the some joint structure 100,101 provided with the hollow shape members 5-9 is formed.

[Friction stir welding process]
Hereinafter, the friction stir welding process of a pair of hollow shape members 6 and 7 will be described as an example. FIGS. 3A to 3C are cross-sectional views illustrating the manufacturing procedure of the joint structures 100 and 101 of FIG. 3A shows the first step, FIG. 3B shows the second step, and FIG. 3C shows the third step. FIG. 4 is a cross-sectional view showing a state in which the pair of hollow members 6 and 7 in FIG.

  First, as a first step, the pair of hollow shapes 6 and 7 are brought close to each other while moving the fitting portions 6e and 7f along the center line X, and the joining end portions 6a1 and 7a2 and the joining end portions 6b1 and 7b2 Approach. Further, the fitting portion 6e and the fitting portion 7f are brought close to each other so that the male tip portion 7h is inserted into the internal space S1 of the female tip portion 6g (FIG. 3A). In the hollow shape members 6 and 7, both the fitting portions 6e and 7f protrude, and the respective leading ends of the fitting portions 6e and 7f are closer to the joining counterpart than the positions of the joining end portions 6a1, 6b1, 7a2, and 7b2. It arrange | positions in the position close | similar to a hollow shape material. Accordingly, the positions of the fitting portions 6e and 7f can be easily confirmed from the outside through the gap between the hollow shape members 6 and 7 to be abutted, and the male tip portion 7h and the female tip portion 6g can be easily aligned.

  Next, as a second step, the male tip 7h is inserted into the internal space S1 of the female tip 6g (FIG. 3B). When the male tip 7h starts to be inserted into the internal space S1, the inclined surfaces 6g1 and 7e1 of the female tip 6g and the male tip 7h come into contact with each other. As a result, the male tip portion 7h advances in the internal space S1 relative to the female tip portion 6g while being guided by the female tip portion 6g, and begins to be fitted into the female tip portion 6g. As shown in FIG. 4, the center line X1 of the hollow shape member 6 and the center line X2 of the hollow shape member 7 are slightly shifted from each other, so that the joining end portions 6a1 and 6b1 of the hollow shape member 6 and the joining end portion of the hollow shape member 7 Even if 7a2 and 7b2 are slightly displaced in the plate thickness direction of the plate portions 6a, 6b, 7a and 7n, the female tip portion 7h is simply inserted into the internal space S1 of the female tip portion 6g. The relative advancing direction of the male tip 7h with respect to the die tip 6g is corrected to an appropriate direction by guiding the inclined surface 6g1 of the female tip 6g, and the male die is positioned at the correct position in the female tip 6g. The front end portion 7h can be fitted. Therefore, even if it does not use a large jig etc., it can align correctly only by abutting and pressing the hollow shape members 6 and 7 from a horizontal direction, and the work burden which aligns the hollow shape members 6 and 7 can be reduced. Further, by inserting the male tip 7h into the female tip 6g, the fitting portions 6e and 7f can be quickly fitted together. Immediately after the second step is performed, the joint ends 6a1 and 7a2 and the joint ends 6b1 and 7b2 are in contact with each other, but the fitting portions 6e and 7f are not yet completely fitted. Thus, in the state before the fitting of the fitting portions 6e and 7f is completed, the joining end portions 6a1 and 7a2 and the joining end portions 6b1 and 7b2 are in contact with each other.

  Next, as a third step, the hollow shape members 6 and 7 are further pressed in the abutting direction in a state where the joining end portions 6a1 and 7a2 and the joining end portions 6b1 and 7b2 are in contact with each other. This operation can be performed, for example, by pressing the hollow shape members 6 and 7 in the abutting direction using a tool such as a vise. As a result, the tip of the male tip 7h is further inserted into the internal space S1 of the female tip 6g, and the fitting portions 6e and 7f are completely fitted (FIG. 3 (c)). When the fitting of the fitting portions 6e and 7f is completed, the joining end portions 6a1 and 7a2 and the joining end portions 6b1 and 7b2 are strongly pressed and come into close contact with a high degree of adhesion. Thereby, joining edge part 6a1, 7a2 and joining edge part 6b1, 7b2 are positioned relatively strongly in an opposing direction, and generation | occurrence | production of position shift is suppressed. In the third step, in addition to pressing the hollow shape members 6 and 7 in the butting direction as described above, the hollow shape members are brought into contact with the joining end portions 6a1 and 7a2 and the joining end portions 6b1 and 7b2. 6 and 7 can also be fixed. By fixing the hollow shape members 6 and 7 in this way, it is possible to suppress the occurrence of misalignment between the joining end portions 6a1 and 7a2 and the joining end portions 6b1 and 7b2.

  Next, a bobbin tool having two large-diameter shoulder portions 10 and 11 and a small-diameter stirring shaft 12 provided therebetween is prepared. The fitting portions 6e and 7f are completely fitted as described above and the hollow shape members 6 and 7 are pressed in the abutting direction, or the fitting portions 6e and 7f are completely fitted and hollow as described above. With the shape members 6 and 7 fixed, the two shoulder portions 10 and 11 rotated sandwich both surfaces of the first plate portions 6a and 7a. At the same time, the stirring shaft 12 is inserted into the butted portion of the hollow shape members 6 and 7. Thereafter, the bobbin tool is moved relative to the hollow shape members 6 and 7 along the abutting portions of the joining end portions 6a1 and 7a2 to perform friction stir welding. In the same manner, friction stir welding is also performed on the joined end portions 6b1 and 7b2 that are brought into contact with each other. Here, in the hollow shape members 6 and 7 which are abutted, the connecting portion 6c and the connecting portion 7d are separated from each other, and spaces S2 and S3 are formed between the connecting portion 6c and the connecting portion 7d. The space S2 is formed between the butted portions of the joining end portions 6a1 and 7a2 and the fitting portions of the fitting portions 6e and 7f. The space S3 is formed between the abutting portions of the joining end portions 6b1 and 7b2 and the fitting portions of the fitting portions 6e and 7f. The spaces S2 and S3 are formed sufficiently wider than the size (width) in the butting direction and the size (height) in the facing direction of the shoulder portion 11 of the bobbin tool disposed inside the hollow shape members 6 and 7. Therefore, it is prevented that the shoulder part 11 interferes with the hollow shape members 6 and 7 in the butting direction and the facing direction. Therefore, the friction stir welding can be favorably performed by inserting the second shoulder portion 11 of the bobbin tool into the spaces S2 and S3, respectively.

  When performing friction stir welding, the fitting portions 6e and 7f are fitted together. Further, as described above, the joining end portions 6a1, 7a2 and the joining end portions 6b1, 7b2 of the hollow shape members 6, 7 are strongly pressed in the abutting direction, or the hollow shape members 6, 7 are fixed, Even if vibration or impact is transmitted from the bobbin tool to the hollow shape members 6 and 7, the hollow shape members 6 and 7 are not easily displaced. Therefore, the hollow shape members 6 and 7 can be appropriately joined while maintaining the relative positional relationship between the joining end portions 6a1 and 7a2 and the joining end portions 6b1 and 7b2. In addition, the fitting portions 6e and 7f are fitted along the center line X passing through the center in the opposing direction, so that the hollow shape members 6 and 7 are connected to the first plate portions 6a and 7a and the second plate portions 6b and 7b. Since each center in the opposing direction is aligned as a reference position, even if each width in the opposing direction of the hollow shape members 6 and 7 has a deviation such as tolerance, the joining end portions 6a1 and 7a2 and the joining end portion 6b1 The occurrence of misalignment with each of 7b2 is minimized.

  By performing friction stir welding as described above, joint structures 100 and 101 are formed, and the hollow shapes 6 and 7 are joined. In the state where the fitting between the fitting portions 6e and 7f is completed, the joining end portions 6a1 and 7a2 and the joining end portions 6b1 and 7b2 and the joining end portions 6b1 are joined together by bringing the joining end portions 6a1 and 7a2 into close contact with each other. , 7b2 is formed with joint structures 100 and 101 that prevent formation of nests or voids. In addition, although the friction stir welding process of the hollow shape members 6 and 7 has been described, the friction stir welding steps of the hollow shape members 5 and 6 and the hollow shape members 7 and 8 are also the first to third steps described above. It can implement by passing through the same each process.

[Modification 1]
FIG. 5 is a partial cross-sectional view showing the joint structure of the hollow members 16 to 18 according to Modification 1 of the first embodiment. As a difference from the first embodiment, in the hollow shape members 16 to 18, the first plate portions 16a to 18a and the second plate portions 16b to 18b are shifted from the center line X passing through the respective centers in the opposing direction. The fitting portions 16e, 17e, 17f, and 18f are arranged. In the hollow shape member 17, a fitting portion 17f is provided at a position close to the first plate portion 17a at a certain distance D1 from the central portion R3 with respect to the connecting portion 17d, and from the central portion R4 to the connecting portion 17c. A fitting portion 17e is provided at a position close to the second plate portion 17b with a certain distance D1. The fitting portion 16e of the hollow shape member 16 and the fitting portion 18f of the hollow shape member 18 are respectively provided at positions where the fitting portions 17f and 17e can be fitted to the connecting portions 16c and 18d. Hereinafter, another embodiment and modification of the present invention will be described focusing on differences from the first embodiment.

(Second Embodiment)
FIG. 6 is a cross-sectional view showing the hollow member 26 according to the second embodiment. FIG. 7 is a partial cross-sectional view showing the joint structures 102 and 103 of the hollow members 25 to 28 according to the second embodiment. Since the hollow shapes 25 to 28 have the same structure, shape and size, the hollow shape 26 will be mainly described. The hollow shape member 26 is provided in the first plate portion 26a and the second plate portion 26b, the connection portions 26c and 26d that connect the first plate portion 26a and the second plate portion 26b in the opposing direction, and the connection portions 26c and 26d. Fitting portions 26e and 26f.

  As shown in FIG. 6, the fitting portions 26e, 26f protrude from the connecting portions 26c, 26d in the abutting direction and are arranged in two wedge-shaped protruding portions 26i, 26j, 26k, 26l arranged in parallel in the opposing direction. Have In the fitting portion 26f, the protruding portion 26j adjacent to the second plate portion 26b functions as a male tip portion 26m, and the slope portions 26i1 and 26j1 facing the two protruding portions 26i and 26j are female tip tips. It functions as the part 26n. In the fitting portion 26e, the protruding portion 26k adjacent to the first plate portion 26a functions as the male tip portion 26o, and the inclined portions 26k1, 2611 facing each other of the two protruding portions 26k, 26l are female-type. It functions as the tip portion 26p. As described above, the fitting portions 26e and 26f include both the male tip portions 26m and 26o and the female tip portions 26n and 26p arranged in reverse order in the facing direction. The fitting portions 26e and 26f have the same structure, shape, and size, and the tips of the fitting portions 26e and 26f are formed into hollow shape members on the mating counterpart side with respect to the joining end portions 26a1, 26a2, 26b1, and 26b2. Arranged in close proximity.

  Each of the fitting portions 26e and 26f is shifted from the center in the opposing direction (central portions R5 and R6) of the first plate portion 26a and the second plate portion 26b by the same distance D2 in the opposite direction along the opposing direction. Be placed. The center portion Q1 of the fitting portion 26f in the facing direction is provided at a position close to the first plate portion 26a at a constant distance D2 from the center portion R5 of the connecting portion 26d. The center portion Q2 of the fitting portion 26e in the facing direction is provided at a position close to the second plate portion 26b at a constant distance D2 from the center portion R6 of the connecting portion 26c.

  The joining end portions 26a2 and 26b1 have convex end surfaces having an arcuate cross section toward the joining end portion on the joining counterpart side. The joining end portions 26a1 and 26b2 have concave end surfaces having an arcuate cross section that can come into surface contact with the convex end surface of the joining end portion on the joining counterpart side. As shown in FIG. 6, the hollow shape member 26 has a point-symmetric shape with the center P as a symmetry point in the cross-sectional direction. The “arc” here is not limited to a semicircular arc (180 ° arc), but also includes an arc having a shorter length than the semicircular portion.

  As shown in FIG. 7, the hollow shape member 25 includes a first plate portion 25a, a second plate portion 25b, a connecting portion 25c, and a fitting portion 25e. The hollow shape member 27 includes a first plate portion 27a, a second plate portion 27b, connecting portions 27c and 27d, and fitting portions 27e and 27f. The hollow shape member 28 includes a first plate portion 28a, a second plate portion 28b, a connecting portion 28d, and a fitting portion 28f. The fitting portions 25e, 27e, 27f, and 28f have the same structure, shape, and size as the fitting portions 26e and 26f. The positions of the fitting portions 25e and 27e with respect to the connecting portions 25c and 27c are set to the same positions as the positions of the fitting portions 26e with respect to the connecting portion 26c, and the positions of the fitting portions 27f and 28f with respect to the connecting portions 27d and 28d are The fitting portion 26f is set to the same position as the connecting portion 26d. The end surfaces of the joining end portions 25a1, 27a1, 27b2, and 28b2 of the hollow shape members 25, 27, and 28 are concave end surfaces having the same arcuate cross section as the concave end surfaces of the joining end portions 26a1 and 26b2. The end surfaces of the joining end portions 25b1, 27a2, 27b1, and 28a2 of the hollow members 25 and 27 are convex end surfaces having the same arcuate cross section as the convex end surfaces of the joining end portions 26a2 and 26b1. As a result, the convex end surfaces of the joining end portions 25b1, 26a2, 26b1, 27a2, 27b1, 28a2 and the concave end surfaces of the joining end portions 25a1, 26a1, 26b2, 27a1, 27b2, 28b2 are in a state of being in surface contact. The profiles 25 to 28 are friction stir welded.

  The male tip portion 26m of the fitting portion 26f is inserted into the female tip portion of the fitting portion 25e, and the male tip portion of the fitting portion 25e is inserted into the female tip portion 26n of the fitting portion 26f. The fitting portions 25e and 26f are fitted together. The male tip 26o of the fitting part 26e is inserted into the female tip of the fitting part 27f, and the male tip of the fitting part 27f is inserted into the female tip 26p of the fitting part 26e. Thus, the fitting portions 26e and 27f are fitted together. The fitting portions 27e and 28f are fitted in the same manner as the fitting portions 25e and 26f and the fitting portions 26e and 27f.

  In the second embodiment, the fitting portions 25e, 26e, 26f, 27e, 27f, and 28f of the hollow members 25 to 28 have both the male tip portion and the female tip portion, and the fitting portion on the joining counterpart side And fitted with a wide contact area. For this reason, at the time of the friction stir welding of the hollow members 25 to 28, it is possible to form the joint structures 102 and 103 in which the displacement of the respective joining end portions is further prevented and the occurrence of misunderstanding is highly suppressed. In addition, by forming the fitting portions 25e, 26e, 26f, 27e, 27f, and 28f with a structure having both a male tip portion and a female tip portion, a fitting portion that can be fitted to each other is realized with a simple structure. Therefore, it is possible to improve the manufacturing efficiency of the hollow members 25 to 28 and improve the joining efficiency of the hollow members 25 to 28. Further, in the hollow shape members 25 to 28, the convex end surfaces of one joint end part 25 b 1, 26 a 2, 26 b 1, 27 a 2, 27 b 1, 28 a 2 in the respective combination of the joint end parts that are butted against each other, By making the surface contact so as to fit into the concave end surfaces of the joint end portions 25a1, 26a1, 26b2, 27a1, 27b2, and 28b2, the above-mentioned joined end portions are not easily displaced. For this reason, the hollow shape members 25 to 28 can be satisfactorily friction stir welded.

  In the second embodiment, each of the fitting portions 25e, 26e, 26f, 27e, 27f, and 28f has a certain thickness in the opposing direction at the root portion. For this reason, in the fitting portions 25e, 26e, 26f, 27e, 27f, and 28f, for example, the thickness of the portion that does not come into contact with the fitting portion on the joining partner side when fitting each other is set to other portions. It may be made thinner. Thereby, weight reduction of the hollow shape members 25-28 can be achieved.

[Modification 1]
FIG. 8 is a partial cross-sectional view showing the joint structures 104 and 105 of the hollow members 35 to 38 according to the modification of the second embodiment. As a difference from the second embodiment, the end surfaces of the joining end portions 35a1, 36a1, 36a2, 37a1, 37a2, 38a2 of the first plate portions 35a, 36a, 37a, 38a of the hollow members 35-38, and the second plate The end surfaces of the joining end portions 35b1, 36b1, 36b2, 37b1, 37b2, and 38b2 of the portions 35b, 36b, 37b, and 38b are formed as inclined surfaces that are inclined with respect to the abutting direction. Thereby, each said joining edge part faced | matched by the hollow shape members 35-38 carries out surface contact in a mutual inclined surface. Therefore, when performing friction stir welding, it is prevented that each said joining edge part produces a position shift in an opposing direction, and generation | occurrence | production of the mistake in the joint structures 104 and 105 can be suppressed.

(Third embodiment)
FIG. 9 is a cross-sectional view showing the joint structures 106 and 107 of the hollow members 46 and 47 according to the third embodiment. As a difference from the first embodiment, the hollow shape member 46 has only a fitting portion 46e having a male tip as a fitting portion. The hollow member 47 has only a fitting part 47f having a female tip as a fitting part. The fitting part 46e has the same structure as the fitting part 6e, and the fitting part 47f has the same structure as the fitting part 7f. The connecting portion 46d of the hollow shape member 46 connects the end portions 46a2 and 46b2 of the first plate portion 46a and the second plate portion 46b, respectively. The connecting portion 47c of the hollow shape member 47 connects the end portions 47a2 and 47b2 of the first plate portion 47a and the second plate portion 47b. In the hollow shape members 46 and 47, the joint end portions 46a1 and 47a1 and the joint end portions 46b1 and 47b1 are friction stir welded in a state where the fitting portions 46e and 47f are fitted together. Thereby, the joint structures 106 and 107 including the hollow members 46 and 47 are formed.

(Fourth embodiment)
FIG. 10 is a cross-sectional view showing joint structures 108 and 109 of the hollow members 56 and 57 according to the fourth embodiment. As a difference from the third embodiment, the hollow members 56 and 57 have fitting portions 56e and 57f having the same configuration as the fitting portions 26e and 27f of the second embodiment. The positions of the fitting portions 56e and 57f with respect to the connecting portions 56c and 57d are the same as the positions of the fitting portions 26e and 27f with respect to the connecting portions 26c and 27d of the second embodiment.

  In the hollow shape members 56 and 57, the position of the center portion R7 of the fitting portions 56e and 57f in the fitted state is the gap G in the facing direction of the first plate portion 56a and the second plate portion 56b of the hollow shape member 56. Coincides with the position of the center G1. Thereby, the hollow shape members 56 and 57 have a point-symmetric shape with the center G1 as a symmetric point when viewed from a direction orthogonal to both the abutting direction and the opposing direction (a direction perpendicular to the paper surface of FIG. 10). Have. Thus, the hollow shape members 56 and 57 are configured to have the same structure, shape and size.

  As a result, in the fourth embodiment, the same two hollow members can be used as the pair of hollow members 56 and 57, so that the manufacturing cost of the hollow members 56 and 57 can be reduced. Specifically, when the hollow shape members 56 and 57 are manufactured by extrusion molding, the hollow shape members 56 and 57 can be manufactured using one same mold.

(Other)
In addition, this invention is not limited to each embodiment mentioned above, The structure can be changed, added, or deleted in the range which does not deviate from the meaning of this invention. The above embodiments may be arbitrarily combined with each other. For example, a part of the configuration in one embodiment may be applied to another embodiment.

  Moreover, in each said embodiment and said each modification, the shape of the 1st board part and 2nd board part of the hollow shape material friction-stir-joined is not limited to flat form, A curved plate form may be sufficient. . Moreover, the length of the some connection part in an opposing direction does not need to be the same. In this case, for example, by making the lengths in the opposing direction of the two connecting portions located at both ends in the abutting direction of the hollow shape member different from each other, the length is viewed from the direction orthogonal to both the abutting direction and the opposing direction of the hollow shape material. The cross section may be substantially trapezoidal.

  In each of the above-described embodiments and each of the above-described modified examples, the example in which the side structure of the railway vehicle structure is configured by friction stir welding a plurality of hollow shapes (see FIG. 1) is shown. By performing friction stir welding in each step similar to the first to third steps shown in the embodiment, at least one of a roof structure and a floor structure, or a pillow beam (not shown) can be configured. In each of the above embodiments and modifications, the railway vehicle structure is illustrated as a structure having a joint structure for friction stir welding, but the structure may be other than the railway vehicle structure.

S1 to S3 Space 1 Railcar structure (structure)
5-9, 16-18, 25-28, 35-38, 46, 47, 56, 57 Hollow profile 5a-8a, 16a-18a, 25a-28a, 35a-38a, 46a, 47a, 56a, 57a 1 plate part 5a1, 5b1, 6a1, 6a2, 6b1, 6b2, 7a1, 7a2, 7b1, 7b2, 8a2, 8b2, 25a1, 25b1, 26a1, 26a2, 26b1, 26b2, 27a1, 27a2, 27b1, 27b2, 28a2, 28b2 Joining end 5b-8b, 16b-18b, 25b-28b, 35b-38b, 46b, 47b, 56b, 57b Second plate 6c, 6d, 7c, 7d, 8d, 16c, 17c, 17d, 18d, 25c, 26c, 26d, 27c, 27d, 28d, 46c, 46d, 47c, 47d, 56c, 56d, 57c, 5 d Connecting part 5e, 6e, 6f, 7e, 7f, 8f, 16e, 17f, 17e, 18f, 25e, 26e, 26f, 27e, 27f, 28f, 46e, 47f, 56e, 57f Fitting part 5g, 6g, 7g 16e, 17e, 26n, 26p Female tip 6f, 7f, 8f, 17f, 18f, 26m, 26o Male tip 5g1, 6g1, 6h1 Inclined surface 10 First shoulder (bobbin tool)
11 Second shoulder (bobbin tool)
101-109 Joint structure

Claims (8)

A first plate portion and a second plate portion arranged so that their plate surfaces are spaced apart from each other, and the first plate portion and the second plate portion in the opposing direction of the first plate portion and the second plate portion. A pair of hollow shapes having a connecting portion for connecting the plate portions, wherein in the pair of hollow shapes, the joining end portions of the first plate portion and the joining end portions of the second plate portion are respectively provided. It is a joint structure that is joined by bobbin tool type friction stir welding method,
Each of the pair of hollow shapes further has a fitting portion that protrudes from the connecting portion toward the hollow shape material on the bonding partner side and is fitted to each other.
In order to form a space through which a bobbin tool that joins the joint ends of the first plate portions and the joint ends of the second plate portions can pass, the connection portions of the pair of hollow profiles Are spaced apart from each other, and the fitting portion is spaced apart from the first plate portion and the second plate portion, so that the abutting portion between the joining end portions of the first plate portion and the fitting portions are separated from each other. The spaces are formed between the fitting portions and between the butted portions of the joining end portions of the second plate portion and the fitting portions of the fitting portions, respectively.
By fitting the fitting portions of the pair of hollow shape members, the joining end portions of the first plate portion and the joining end portions of the second plate portion are arranged in the facing direction. Friction stir welding joint structure that is relatively positioned.   Of the pair of hollow profiles, the fitting portion of at least one of the hollow profiles includes a male tip that projects toward the hollow profile on the mating counterpart side, and at least the other of the hollow profiles. The joint structure of friction stir welding according to claim 1, wherein the fitting portion includes a female tip portion fitted to the male tip portion of the fitting portion of the hollow shape member on the joining partner side.   The male tip portion and the female tip portion have inclined surfaces that are inclined with respect to the abutting direction of the pair of hollow profiles, and the fitting portions of the pair of hollow profiles are mutually The joint structure of friction stir welding according to claim 2, wherein the inclined surfaces are fitted together by contact. Each of the fitting portions of the pair of hollow shape members includes both the male tip portion and the female tip portion arranged in reverse order in the facing direction, and from the center in the facing direction, Are arranged at the same distance in the opposite directions in the opposite direction, and are offset
Each of the hollow profiles of the pair of hollow profiles is point-symmetric with respect to the center of the opposing direction as viewed from a direction orthogonal to both the butting direction of the pair of hollow profiles and the opposing direction. The joint structure for friction stir welding according to claim 2 or 3, wherein the joint structure has a shape to become.   In a state before the fitting between the fitting parts of the pair of hollow shapes is completed, the joining end parts of the first plate part and the joining end parts of the second plate part are respectively The joint structure of friction stir welding according to any one of claims 1 to 4, which comes into contact.   The front ends of the fitting portions of the pair of hollow shapes are arranged at positions closer to the joining counterpart side than the positions of the joining end portions of the first plate portion and the second plate portion, The joint structure of friction stir welding according to any one of claims 1 to 5.   In each combination of the joint ends that are abutted against each other, one of the joint ends has a convex end surface with an arc-shaped cross-section that bulges toward the other joint end, and the other of the joints. The joint structure for friction stir welding according to any one of claims 1 to 6, wherein the end portion has a concave end surface having an arc-shaped cross section that can come into surface contact with the convex end surface.   A structure provided with the joint structure of friction stir welding of any one of Claims 1-7.

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