Method for manufacturing structural members and molds

Abstract

The present invention provides a manufacturing method that enables the production of multiple structural members in a reduced number of steps. [Solution] The manufacturing method is a method for manufacturing separate first structural member (10) and second structural member (20). The manufacturing method comprises the steps of: preparing a material (40) including a first blank (41) and a second blank (42), wherein the first blank (41) and the second blank (42) are not joined in the regions (411, 421) that will become the first structural member (10) and the second structural member (20); and holding the material (40) with a first mold (31) and a second mold (32), and supplying fluid between the first blank (41) and the second blank (42) to deform the material (40) in a hollow space to form a first molded product (51) including the first structural member (10) from the first blank (41), and forming a second molded product (52) including the second structural member (20) from the second blank (42).

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing structural members, and more particularly, to a manufacturing method for manufacturing a first structural member and a second structural member separate from the first structural member. The present disclosure also relates to a mold.

Background Art

[0002] In recent years, in vehicle bodies such as automobiles, reduction of greenhouse gas (life cycle GHG) emissions throughout the life cycle of the vehicle body has been required. In order to reduce life cycle GHG emissions by reducing the number of parts of the vehicle body, integration of parts has been promoted.

[0003] For example, Patent Document 1 discloses a rear module of a vehicle body. The rear module of Patent Document 1 includes left and right rear rails. Each of the rear rails includes a front portion, a rear portion, and a transition region connecting these. Each of the rear rails is formed, for example, by a tailor welded blank or a tailor rolled blank. Therefore, in Patent Document 1, the front portion and the rear portion of the rear rail are integrated from the blank stage.

[0004] Similarly, Patent Document 2 discloses a technique for integrating the front portion and the rear portion of a rear rail from the blank stage.

[0005] Patent Document 3 also discloses a rear module of a vehicle body. The rear module of Patent Document 3 includes left and right side members and a cross member connecting the side members. This rear module is formed by a single tailor welded blank. Therefore, in Patent Document 3, the left and right side members and the cross member are integrated from the blank stage.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] Each patent document describes a technique for press-forming multiple parts as a single integrated component by using a tailored blank containing multiple subblanks. By reducing the number of parts in a vehicle body and other components through the use of integrated components, life cycle GHG emissions can be reduced. Life cycle GHG emissions can also be reduced by omitting manufacturing processes. For example, in automobiles, in order to manufacture each module of the vehicle body by assembling multiple structural members, multiple molding processes corresponding to each structural member and a process for assembling the molded structural members are required. If some of these processes can be omitted, life cycle GHG emissions can be reduced, and the manufacturing cost of the vehicle body can also be reduced.

[0008] The object of this disclosure is to provide a manufacturing method that enables the production of multiple structural members in a reduced number of steps. [Means for solving the problem]

[0009] The manufacturing method relating to this disclosure is a method for manufacturing a first structural member and a second structural member separate from the first structural member. The manufacturing method comprises the steps of: preparing a material including a first blank and a second blank superimposed on the first blank, wherein the first blank and the second blank are not joined in the regions of the material that will become the first structural member and the second structural member; and holding the material with a first mold and a second mold and supplying fluid between the first blank and the second blank to deform the material in the hollow space formed by the first mold and the second mold to form a first molded product including the first structural member from the first blank, and forming a second molded product including the second structural member from the second blank. [Effects of the Invention]

[0010] According to the manufacturing method described herein, multiple structural members can be manufactured in a reduced number of steps. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a perspective view showing the schematic configuration of the structural members in the first embodiment. [Figure 2] Figure 2 is a cross-sectional view of the side frame included in the structural member shown in Figure 1. [Figure 3] Figure 3 is a cross-sectional view of a cross member included in the structural member shown in Figure 1. [Figure 4] Figure 4 is a perspective view showing the schematic configuration of the mold in the first embodiment. [Figure 5A] Figure 5A is a cross-sectional view of the mold shown in Figure 4. [Figure 5B] Figure 5B is another cross-sectional view of the mold shown in Figure 4. [Figure 6A] Figure 6A is a schematic diagram illustrating the manufacturing method of a structural member according to the first embodiment. [Figure 6B] Figure 6B is a schematic diagram illustrating the manufacturing method of a structural member according to the first embodiment. [Figure 6C] Figure 6C is a schematic diagram illustrating the manufacturing method of a structural member according to the first embodiment. [Figure 6D] FIG. 6D is a schematic diagram for explaining a method of manufacturing a structural member according to the first embodiment. [Figure 6E] FIG. 6E is a schematic diagram for explaining a method of manufacturing a structural member according to the first embodiment. [Figure 6F] FIG. 6F is a schematic diagram for explaining a method of manufacturing a structural member according to the first embodiment. [Figure 6G] FIG. 6G is a schematic diagram for explaining a method of manufacturing a structural member according to the first embodiment. [Figure 7] FIG. 7 is a perspective view showing a schematic configuration of a structural member in the second embodiment. [Figure 8A] FIG. 8A is a schematic diagram for explaining a method of manufacturing a structural member according to the second embodiment. [Figure 8B] FIG. 8B is a schematic diagram for explaining a method of manufacturing a structural member according to the second embodiment. [Figure 8C] FIG. 8C is a schematic diagram for explaining a method of manufacturing a structural member according to the second embodiment. [Figure 9] FIG. 9 is a perspective view showing a schematic configuration of a structural member in the third embodiment. [Figure 10A] FIG. 10A is a schematic diagram for explaining a method of manufacturing a structural member according to the third embodiment. [Figure 10B] FIG. 10B is a schematic diagram for explaining a method of manufacturing a structural member according to the third embodiment. [Figure 11] FIG. 11 is a perspective view showing a schematic configuration of a structural member in the fourth embodiment. [Figure 12A] FIG. 12A is a schematic diagram for explaining a method of manufacturing a structural member according to the fourth embodiment. [Figure 12B] FIG. 12B is a schematic diagram for explaining a method of manufacturing a structural member according to the fourth embodiment. [Figure 13] FIG. 13 is a perspective view showing a schematic configuration of a structural member in the fifth embodiment. [Figure 14A]Figure 14A is a schematic diagram illustrating the manufacturing method of a structural member according to the fifth embodiment. [Figure 14B] Figure 14B is a schematic diagram illustrating the manufacturing method of a structural member according to the fifth embodiment. [Figure 14C] Figure 14C is a schematic diagram illustrating the manufacturing method of a structural member according to the fifth embodiment. [Figure 15] Figure 15 is a cross-sectional view showing the schematic configuration of the structural member in the sixth embodiment. [Figure 16A] Figure 16A is a schematic diagram illustrating the manufacturing method of a structural member according to the sixth embodiment. [Figure 16B] Figure 16B is a schematic diagram illustrating the manufacturing method of a structural member according to the sixth embodiment. [Figure 16C] Figure 16C is a schematic diagram illustrating the manufacturing method of a structural member according to the sixth embodiment. [Figure 17] Figure 17 is a cross-sectional view showing an example of a structural member in the seventh embodiment. [Figure 18] Figure 18 is a cross-sectional view showing another example of a structural member in the seventh embodiment. [Figure 19A] Figure 19A is a schematic diagram illustrating the manufacturing method of a structural member according to the seventh embodiment. [Figure 19B] Figure 19B is a schematic diagram illustrating the manufacturing method of a structural member according to the seventh embodiment. [Figure 19C] Figure 19C is a schematic diagram illustrating the manufacturing method of a structural member according to the seventh embodiment. [Figure 20] Figure 20 is a cross-sectional view of the mold according to the eighth embodiment. [Figure 21A] Figure 21A is a schematic diagram illustrating the manufacturing method of a structural member using the mold shown in Figure 20. [Figure 21B] Figure 21B is a schematic diagram illustrating the manufacturing method of a structural member using the mold shown in Figure 20. [Modes for carrying out the invention]

[0012] The manufacturing method according to the embodiment is a manufacturing method for producing a first structural member and a second structural member separate from the first structural member. The manufacturing method comprises the steps of: preparing a material including a first blank and a second blank superimposed on the first blank, wherein the first blank and the second blank are not joined in the regions of the material that will become the first structural member and the second structural member; and holding the material with a first mold and a second mold and supplying fluid between the first blank and the second blank to deform the material in the hollow space formed by the first mold and the second mold to form a first molded product including the first structural member from the first blank, and forming a second molded product including the second structural member from the second blank (first configuration).

[0013] In the manufacturing method relating to the first configuration, a material including a superimposed first blank and a second blank is molded using a first mold and a second mold. More specifically, the material is held by the first mold and the second mold, and a fluid is supplied between the first blank and the second blank, thereby deforming the material in the hollow space formed by the first mold and the second mold. As a result, a first molded product including a first structural member is molded from the first blank, and a second molded product including a second structural member is molded from the second blank. In other words, the first structural member and the second structural member are molded simultaneously in a single process. Therefore, the number of molding processes can be reduced compared to the case where the first structural member and the second structural member are molded in separate molding processes, and multiple structural members can be manufactured productively with fewer processes.

[0014] In the first configuration, the first blank and the second blank are not joined in the region of the material that will become the first structural member and the second structural member. That is, the first blank and the second blank are not constrained in the region of the material that will become the first structural member and the second structural member. Therefore, in the molding process, material flows easily into the hollow space formed by the first mold and the second mold, and the first structural member and the second structural member can be molded well. For example, even if the molding height of the first structural member and / or the second structural member is large, these structural members can be molded while suppressing the occurrence of cracks, wrinkles, etc.

[0015] When forming is performed after joining the regions of the material that will become the first and second structural members by spot welding, plastic deformation may cause a displacement of approximately 1.0 mm in the weld points between the first and second structural members. When a displacement occurs in the weld points, the strength of the joint, specifically the tensile shear strength (TSS), of the spot weld decreases. For example, when forming the first and second structural members by hot forming (hot stamping), plastic deformation at the weld points makes ferrite transformation more likely to occur at the weld points, which tends to reduce hardenability. Also, for example, when forming the first and second structural members by cold forming, plastic deformation at the weld points makes local deformation or cracks more likely to occur at the weld points. In contrast, in the manufacturing method relating to the first configuration, forming is performed with no joints present in at least the regions of the material that will become the first and second structural members. The first and second structural members are joined together as needed after the forming process. In this case, since no plastic deformation occurs at the joint between the first structural member and the second structural member, the tensile shear strength (TSS) of the joint can be ensured.

[0016] In the manufacturing method relating to the first configuration, the molding step may involve molding a first molded product including a first structural member and a second molded product including a second structural member having a different shape from the first structural member (second configuration).

[0017] In the manufacturing method relating to the second configuration, the molding height of the first structural member may differ from the molding height of the second structural member during the molding process (third configuration).

[0018] If the first blank and the second blank are joined in the region of the material that will become the first and second structural members, and the molding heights of the first and second structural members differ, then insufficient material flow may occur in structural members with a large molding height, or excessive material flow may occur in structural members with a small molding height, potentially resulting in molding defects such as wrinkles in the first or second structural member. However, in the above manufacturing method, the first blank and the second blank are not joined in at least the region of the material that will become the first and second structural members, and the first and second blanks are not constrained in that region. Therefore, as in the third configuration, if the molding height of the first structural member and the molding height of the second structural member differ, a difference in material flow corresponding to the difference in molding height can be tolerated. That is, the amount of material flow can be relatively increased in structural members with a large molding height, and relatively decreased in structural members with a small molding height. Thus, the first and second structural members can be molded while suppressing the occurrence of wrinkles and other defects.

[0019] A manufacturing method relating to any of the first to third configurations may further include a step of trimming the first molded product and the second molded product after the molding step to obtain the first structural member and the second structural member (fourth configuration).

[0020] The mold according to the embodiment comprises a first mold and a second mold. The first mold and the second mold each include a molding surface and a flange surface disposed around the molding surface. One of the first and second molds includes a fluid supply port formed on the surface facing the other of the first and second molds, and a positioning pin provided on the surface and positioned outside the molding surface beyond the fluid supply port when viewed in a longitudinal cross-section passing through the centroid of the molding surface and the center of the fluid supply port. The other of the first and second molds includes a recess formed on the surface facing the one of the first and second molds at a position corresponding to the positioning pin (fifth configuration).

[0021] The mold relating to the fifth configuration can be suitably used in the above manufacturing method. In particular, it is preferable to use this mold when the first blank and the second blank are not joined in areas of the material other than the areas that become the first structural member and the second structural member, and the first blank and the second blank are independent. Specifically, in the mold relating to the fifth configuration, one of the first mold and the second mold includes a positioning pin. The positioning pin is positioned near a fluid supply port. In this case, for example, a notch can be provided at the edge of the part of the material where the first blank and the second blank overlap, and the positioning pin can be placed in the notch when molding the material. This makes it less likely for misalignment between the first blank and the second blank to occur. Therefore, even when the first blank and the second blank are independent, it becomes easier to simultaneously mold a first molded product including the first structural member and a second molded product including the second structural member.

[0022] In the mold according to the fifth configuration, one of the first mold and the second mold includes a convex sealing portion provided on the surface facing the other of the first mold and the second mold, which surrounds the molding surface. The sealing portion includes a portion located between the fluid supply port and the positioning pin (sixth configuration).

[0023] In the sixth configuration, a convex sealing portion is provided on one of the first mold and the second mold. The sealing portion is positioned to surround the molding surface on one of the first mold and the second mold. When the first mold and the second mold are closed, the sealing portion can seal the first blank and the second blank on the outside of the molding surface. Therefore, when fluid is supplied between the first blank and the second blank, fluid leakage is less likely to occur. Thus, simultaneous molding of the first structural member and the second structural member can be performed more effectively.

[0024] Embodiments of this disclosure will be described below with reference to the drawings. In these drawings, the same or equivalent components are denoted by the same reference numerals, and the same description will not be repeated.

[0025] <First Embodiment> [Structural members] Figure 1 is a perspective view showing the schematic configuration of the first structural member 10 and the second structural member 20 in this embodiment. The structural members 10 and 20 are rear frames for a vehicle body. In this case, the structural members 10 and 20 are provided at the rear and lower part of a vehicle body such as an automobile. The first structural member 10 is positioned above the second structural member 20 when incorporated into the vehicle body. The first structural member 10 is the rear frame upper, and the second structural member 20 is the rear frame lower.

[0026] The first structural member 10 includes a pair of side frames 11 and at least one cross member 12. The first structural member 10 may include a plurality of cross members 12. When the first structural member 10 is incorporated into the vehicle body, each side frame 11 extends in the longitudinal direction (vehicle length direction) of the vehicle body. The side frames 11 are connected by the cross members 12. The side frames 11 are connected by the cross members 12, for example, at their longitudinal intermediate portions. The cross members 12 extend from one side frame 11 to the other side frame 11. When the first structural member 10 is incorporated into the vehicle body, the cross members 12 extend in the lateral direction (vehicle width direction) of the vehicle body.

[0027] The second structural member 20 includes a pair of side frames 21 and at least one cross member 22. The second structural member 20 may include a plurality of cross members 22. The side frames 21 each extend in the vehicle length direction when the second structural member 20 is incorporated into the vehicle body. The side frames 21 are connected by the cross members 22. The side frames 21 are connected by the cross members 22, for example, at their longitudinal intermediate portions. The cross members 22 extend from one side frame 21 to the other side frame 21. The cross members 22 extend in the vehicle width direction when the second structural member 20 is incorporated into the vehicle body.

[0028] With the structural members 10 and 20 assembled into the vehicle body, the side frame 11 of the first structural member 10 is joined to the side frame 21 of the second structural member 20. Figure 2 is a cross-sectional view (sectional plane) of the side frames 11 and 21 perpendicular to the longitudinal direction.

[0029] Referring to Figure 2, the side frame 11 may have a substantially hat shape in cross-sectional view. In this embodiment, the side frame 11 includes a top plate 111, two vertical walls 112, and two flanges 113. In cross-sectional view of the side frame 11, the vertical walls 112 are located on both sides of the top plate 111. Each vertical wall 112 is connected to the top plate 111 via a ridge 114. The flanges 113 are connected to the vertical walls 112 on the opposite side of the top plate 111 via a ridge 115. The flanges 113 project outward from the vertical walls 112 toward the side frame 11.

[0030] In this embodiment, the side frame 21 forms a closed section together with the side frame 11 when the structural members 10 and 20 are incorporated into the vehicle body. The side frame 21 may have a substantially hat shape in cross-sectional view. The side frame 21 includes a top plate 211, two vertical walls 212, and two flanges 213. The top plate 211 faces the top plate 111 of the side frame 11. In a cross-sectional view of the side frame 21, the vertical walls 212 are located on both sides of the top plate 211. The vertical walls 212 are each connected to the top plate 211 via ridges 214. The flanges 213 are on the opposite side of the top plate 211 and are each connected to the vertical walls 212 via ridges 215. The flanges 213 project outward from the vertical walls 212 toward the side frame 21. The flanges 213 are joined to the flanges 113 of the side frame 11. The flanges 113 and 213 are joined, for example, by spot welding. Flanges 113 and 213 may be joined by laser welding or the like.

[0031] With the structural members 10 and 20 assembled into the vehicle body, the cross member 12 of the first structural member 10 is also joined to the cross member 22 of the second structural member 20. Figure 3 is a cross-sectional view (sectional plane view) of the cross members 12 and 22 perpendicular to the longitudinal direction.

[0032] Referring to Figure 3, the cross member 12 may have a substantially hat shape in cross view. In this embodiment, the cross member 12 includes a top plate 121, two vertical walls 122, and two flanges 123. In a cross view of the cross member 12, the vertical walls 122 are located on both sides of the top plate 121. Each vertical wall 122 is connected to the top plate 121 via a ridge 124. The flanges 123 are on the opposite side of the top plate 121 and are connected to the vertical walls 122 via a ridge 125. The flanges 123 project outward from the vertical walls 122.

[0033] In this embodiment, the cross member 22 forms a closed section together with the cross member 12 when the structural members 10 and 20 are incorporated into the vehicle body. The cross member 22 may have a substantially hat shape in cross view. The cross member 22 includes a top plate 221, two vertical walls 222, and two flanges 223. The top plate 221 faces the top plate 121 of the cross member 12. In a cross view of the cross member 22, the vertical walls 222 are located on both sides of the top plate 221. The vertical walls 222 are each connected to the top plate 221 via ridges 224. The flanges 223 are on the opposite side of the top plate 221 and are each connected to the vertical walls 222 via ridges 225. The flanges 223 project outward from the vertical walls 222 toward the cross member 22. The flanges 223 are joined to the flanges 123 of the cross member 12. The flanges 123 and 223 are joined by, for example, spot welding. Alternatively, the flanges 123 and 223 may be joined by laser welding or the like.

[0034] [Mold] Figure 4 is a perspective view showing the schematic configuration of the mold 30 in this embodiment. The structural members 10 and 20 (Figure 1) can be manufactured using the mold 30.

[0035] Referring to Figure 3, the mold 30 comprises a first mold 31 and a second mold 32. The first mold 31 and the second mold 32 are a pair of molds. When the mold 30 is in use, the first mold 31 and the second mold 32 are mounted on a press or the like so that they can approach each other relatively. Hereinafter, the direction in which the first mold 31 and the second mold 32 approach each other will be referred to as the processing direction D. The processing direction D is, for example, the vertical direction.

[0036] The first mold 31 is a mold primarily for molding the first structural member 10 (Figure 1). The first mold 31 includes a molding surface 311 and a flange surface 312. The molding surface 311 and the flange surface 312 are provided on the surface of the first mold 31 that faces the processing direction D relative to the second mold 32.

[0037] The molded surface 311 is formed to correspond to the portion of the first structural member 10 that is convex upward relative to the flanges 113 and 123 (Figures 1 to 3). In this embodiment, the molded surface 311 has a shape that corresponds to the top plate 111, vertical wall 112, and ridge portions 114 and 115 (Figure 2) of the side frame 11 of the first structural member 10, and the top plate 121, vertical wall 122, and ridge portions 124 and 125 (Figure 3) of the cross member 12. When viewed along the processing direction D, the flange surface 312 is arranged around the molded surface 311.

[0038] In this embodiment, the second mold 32 is located below the first mold 31. The second mold 32 is a mold primarily for molding the second structural member 20 (Figure 1). The second mold 32 includes a molding surface 321 and a flange surface 322. The molding surface 321 and the flange surface 322 are provided on the surface of the second mold 32 that faces the processing direction D relative to the first mold 31.

[0039] The molded surface 321 is formed to correspond to the portion of the second structural member 20 that is concave downward relative to the flanges 213 and 223 (Figures 1 to 3). In this embodiment, the molded surface 321 has a shape that corresponds to the top plate 211, vertical wall 212, and ridge portions 214 and 215 (Figure 2) of the side frame 21 of the second structural member 20, and the top plate 121, vertical wall 122, and ridge portions 124 and 125 (Figure 3) of the cross member 22. When viewed along the processing direction D, the flange surface 322 is arranged around the molded surface 321.

[0040] The molding surface 321 of the second mold 32, together with the molding surface 311 of the first mold 31, forms a hollow space. Therefore, when the mold 30 is in use, the molding surfaces 311 and 321 face the processing direction D. One or both of the molding surfaces 311 and 321 have a concave shape in at least a part of them. In this embodiment, each of the molding surfaces 311 and 321 has an overall concave shape. More specifically, in the first mold 31, the molding surface 311 is formed to be concave with respect to the flange surface 312. In the second mold 32, the molding surface 321 is formed to be concave with respect to the flange surface 322.

[0041] One of the first mold 31 and the second mold 32 may include convex sealing portions 33 and 34. In this embodiment, the other of the first mold 31 and the second mold 32 also includes convex sealing portions 33 and 34. That is, each of the first mold 31 and the second mold 32 includes sealing portions 33 and 34. The sealing portion 33 is made of, for example, metal. The sealing portion 33 may be formed integrally with the first mold 31 or the second mold 32. The outer peripheral sealing portion 34 may be made of metal, but may also be made of an elastic material such as resin. When the sealing portion 34 is provided in the first mold 31 and / or the second mold 32, the sealing portion 34 may be a resin packing such as an O-ring. In this case, the mold having the sealing portion 34 among the first mold 31 and the second mold 32 has a groove for arranging the sealing portion 34.

[0042] In the first mold 31, the sealing portions 33 and 34 are provided on the surface facing the second mold 32. The sealing portions 33 and 34 are provided, for example, on the flange surface 312. The sealing portion 33 substantially surrounds the molding surface 311 when viewed along the machining direction D. The sealing portion 33 may surround the molding surface 311 without interruption around its entire circumference, but may be interrupted in part at positions relatively far from the fluid supply port, for example, described later. The sealing portion 33 may be interrupted at positions far from each fluid supply port, for example, in a range of 150 mm or less.

[0043] In the first mold 31, the seal portion 34 substantially surrounds the seal portion 33 when viewed along the machining direction D. That is, the first mold 31 is provided with a double layer of seal portions 33 and 34. The seal portion 34 may surround the seal portion 33 without interruption around its entire circumference, but it may be interrupted in part, for example, at a position relatively far from the fluid supply port. The seal portion 34 may be interrupted at a position far from the fluid supply port, for example, in a range of 150 mm or less.

[0044] In the second mold 32, the sealing portions 33 and 34 are provided on the surface facing the first mold 31. The sealing portions 33 and 34 are provided, for example, on the flange surface 322. The sealing portion 33 substantially surrounds the molding surface 321 when viewed along the machining direction D. The sealing portion 33 of the second mold 32 is provided so as to face the sealing portion 33 of the first mold 31 in the machining direction D, and has a shape corresponding to the sealing portion 33 of the first mold 31. In the second mold 32 as well, the sealing portion 33 may surround the molding surface 321 without interruption around its entire circumference, or it may be interrupted in a range of, for example, 150 mm or less.

[0045] In the second mold 32, the seal portion 34 substantially surrounds the seal portion 33 when viewed along the machining direction D. That is, the second mold 32 is provided with a double set of seal portions 33 and 34. The seal portion 34 of the second mold 32 is provided so as to face the seal portion 34 of the first mold 31 in the machining direction D, and has a shape corresponding to the seal portion 34 of the first mold 31. In the second mold 32 as well, the seal portion 34 may surround the seal portion 33 without interruption around its entire circumference, or it may be interrupted in a range of, for example, 150 mm or less.

[0046] The second mold 32 may have at least one projection 35. The projection 35 is formed, for example, on the flange surface 322 of the second mold 32. In this embodiment, multiple projections 35 are formed on the flange surface 322. The projections 35 are arranged, for example, on both sides of the portion of the molding surface 321 corresponding to the cross member 22 (Figure 1).

[0047] Each of the projections 35 has, for example, a circular shape when viewed along the machining direction D. However, the projections 35 may have a polygonal shape such as a triangular or quadrilateral shape when viewed along the machining direction D. If the projections 35 have a shape other than a circle, they may be formed to be wider on the side facing the molded surface 321.

[0048] Figures 5A and 5B are cross-sectional views of the mold 30 shown in Figure 4. Figures 5A and 5B show the longitudinal section of the mold 30 at the position of the projection 35. The longitudinal section of the mold 30 is the section along the machining direction D.

[0049] First, referring to Figure 5A, one of the first mold 31 and the second mold 32 includes at least one fluid supply port 36. The fluid supply port 36 is formed on the surface of one of the first mold 31 and the second mold 32 that faces the other. In this embodiment, the second mold 32 has the fluid supply port 36. More specifically, the second mold 32 has a fluid channel 37 inside, the end of which opens to the surface of the second mold 32 as the fluid supply port 36. The channel 37 is connected to a fluid supply source (not shown) provided outside the second mold 32.

[0050] In the flow path 37, the end opposite to the fluid supply port 36 can open, for example, to the side of the second mold 32. However, if multiple flow paths 37 are provided in the second mold 32, these flow paths 37 may be consolidated into a single system within the second mold 32 and then open to the back of the second mold 32 or the like.

[0051] The fluid supply port 36 may be located on the projection 35. The projection 35 having the fluid supply port 36 includes a tip surface 351 and a side surface 352. The tip surface 351 is the surface of the projection 35 that is located furthest from the flange surface 322. In this embodiment, the tip surface 351 is a flat surface substantially perpendicular to the machining direction D.

[0052] The side surface 352 connects the tip surface 351 to the flange surface 322. In this embodiment, when viewed in a longitudinal cross-section of the mold 30, the side surface 352 is inclined with respect to the machining direction D such that the width of the projection 35 is larger at the base end and smaller at the tip end.

[0053] Figure 5B shows another example of the projection 35. In the example in Figure 5A, the side surface 352 of the projection 35 is an inclined surface that is inclined overall with respect to the machining direction D, but in the example in Figure 5B, a step is provided on the side surface 352 at the base end of the projection 35. That is, when viewed in a longitudinal cross-section of the mold 30, the portion 353 of the side surface 352 adjacent to the flange surface 322 is substantially parallel to the machining direction D. Therefore, the width of the projection 35 is substantially constant in the portion 353 of the side surface 352 adjacent to the flange surface 322. Other portions of the side surface 352 may be inclined with respect to the machining direction D, as in Figure 5A.

[0054] The fluid supply port 36 is located, for example, on the side surface 352 of the projection 35. The fluid supply port 36 is located on the side surface 352 of the projection 35 that is on the molding surface 321 side. Preferably, the fluid supply port 36 is located on the tip side of the projection 35. In the examples in Figures 5A and 5B, the portion of the flow path 37 having the fluid supply port 36 at its end that passes through the projection 35 is substantially parallel to the machining direction D. However, at least the portion of the flow path 37 that passes through the projection 35 may be inclined with respect to the machining direction D. The flow path 37 can be inclined with respect to the machining direction D so as to intersect the side surface 352 of the projection 35 when viewed in the longitudinal section of the mold 30. At least the portion of the flow path 37 that passes through the projection 35 may be inclined with respect to the machining direction D at an angle of more than 0° and less than or equal to 60° when viewed in the longitudinal section of the mold 30.

[0055] Near the projection 35, a relief portion 312a is formed on the flange surface 312 of the first mold 31. Viewed in a longitudinal section of the mold 30, the relief portion 312a extends from the portion of the flange surface 312 facing the tip surface 351 of the projection 35 to the molding surface 311. The relief portion 312a has a concave shape relative to the rest of the flange surface 312.

[0056] The sealing portions 33 and 34 of the first mold 31 and the second mold 32 preferably have a shape that allows surface contact with the mating mold or its sealing portions 33 and 34. Each of the sealing portions 33 and 34 may, for example, have a substantially rectangular cross-section. The width of each sealing portion 33 and 34 may be 1.0 mm or more, and preferably 2.0 mm or more. The width of each sealing portion 33 and 34 is preferably 5.0 mm or less, and more preferably 3.0 mm or less. The height of each sealing portion 33 and 34 is, for example, 0.2 mm or more. The height of each sealing portion 33 and 34 may be 0.5 mm or less.

[0057] [Method for manufacturing structural members] Next, the manufacturing method for the structural members 10 and 20 will be described with reference to Figures 6A to 6G. The manufacturing method according to this embodiment comprises a preparation step and a molding step. The manufacturing method may further include a heating step.

[0058] (preparation process) As shown in Figures 6A and 6B, the preparation step involves preparing the material 40. The material 40 includes a first blank 41 and a second blank 42.

[0059] The first blank 41 is a blank corresponding to the first structural member 10 (Figure 1). The first blank 41 includes regions 411 and 412. Region 411 is the region of the first blank 41 that will be molded into the first structural member 10 by a molding process described later. Region 412 is the region of the first blank 41 other than region 411. In this embodiment, region 412 is provided around region 411.

[0060] The second blank 42 is a blank corresponding to the second structural member 20 (Figure 1). The second blank 42 includes regions 421 and 422. Region 421 is the region of the second blank 42 that will be molded into the second structural member 20 by a molding process described later. Region 422 is the region of the second blank 42 other than region 421. In this embodiment, region 422 is provided around region 421.

[0061] Through holes 43 are formed in the second blank 42. In this embodiment, multiple through holes 43 are formed in the second blank 42. The through holes 43 are located, for example, in the region 422 of the second blank 42 outside the second structural member 20 (Figure 1).

[0062] The second blank 42 is superimposed on the first blank 41. The second blank 42 may or may not be joined to the first blank 41. However, in the regions 411 and 421 of the material 40 that will become the first structural member 10 and the second structural member 20 (Figure 1), the first blank 41 and the second blank 42 are not joined. In the regions 412 and 422 of the material 40 outside the structural members 10 and 20, the first blank 41 and the second blank 42 may be joined (temporarily fixed) by, for example, spot welding.

[0063] The first blank 41 and the second blank 42 may each be formed from a single metal sheet, or they may each include multiple metal sheets (subblanks). The metal sheets may be, for example, iron sheets (steel sheets) or non-ferrous metal sheets such as aluminum alloy sheets. The first blank 41 and the second blank 42 may be formed from different types of metal sheets. For example, one of the first blank 41 and the second blank 42 may be formed from one or more iron sheets (steel sheets), and the other of the first blank 41 and the second blank 42 may be formed from one or more non-ferrous metal sheets.

[0064] If the first blank 41 includes multiple metal plates, these metal plates may differ in at least one of their tensile strength and thickness. If the first blank 41 includes multiple metal plates, the metal plates are joined together, for example, by welding. Similarly, if the second blank 42 includes multiple metal plates, these metal plates may differ in at least one of their tensile strength and thickness. If the second blank 42 includes multiple metal plates, the metal plates are joined together, for example, by welding. The metal plates are joined together, for example, by spot welding or laser welding. In each of the first blank 41 and the second blank 42, adjacent metal plates may be joined with their end faces butted together, or with their ends overlapping together.

[0065] (Heating process) The heating process is carried out before the forming process. In the heating process, the prepared material 40 is heated. The material 40 is heated, for example, in a heating furnace. The heating temperature of the material 40 is determined according to the material of the first blank 41 and the second blank 42. If the first blank 41 and the second blank 42 are formed from steel sheets, the material 40 is heated to the austenite transformation completion temperature (A) of the first blank 41 and the second blank 42. c3 It is preferable to heat the material to a temperature of 900°C or higher. If the first blank 41 and the second blank 42 are made of steel plates, the material 40 is heated to, for example, 900°C or higher. However, the heating step is not necessarily required.

[0066] (molding process) In the molding process, structural members 10 and 20 (Figure 1) are formed from the material 40 using the first mold 31 and the second mold 32. The molding process may be a cold forming process or a hot forming process (hot stamping). If the molding process is a hot forming process, a heating process is performed before the molding process, and in the molding process, the heated material 40 is formed into structural members 10 and 20.

[0067] Referring to Figure 6C, in the molding process, first, with the first mold 31 and the second mold 32 separated in the processing direction D, the material 40 is placed between the first mold 31 and the second mold 32. At this time, the material 40 is placed between the first mold 31 and the second mold 32 such that the first blank 41 is located on the first mold 31 side and the second blank 42 is located on the second mold 32 side. If the second mold 32 is located below the first mold 31, the material 40 may be placed on the second mold 32. In this embodiment, the material 40 is placed such that each through hole 43 of the second blank 42 corresponds to the projection 35 of the second mold 32.

[0068] Referring to Figure 6D, the first mold 31 and the second mold 32 are then brought relatively close together and closed, holding the material 40 between them. The first mold 31 and the second mold 32 clamp the area of ​​the material 40 that is at least the region where the first blank 41 and the second blank 42 overlap, and is outside the structural members 10,20 (Figure 1), specifically the areas 412,422 (Figures 6A and 6B). The first mold 31 and the second mold 32 can further clamp the areas 411,421 (Figures 6A and 6B) that will become the structural members 10,20, specifically the portions that will be formed into the flanges 113,213 (Figure 2) of the side frames 11,21 and the flanges 123,223 (Figure 3) of the cross members 12,22.

[0069] In this embodiment, with the projections 35 of the second mold 32 inserted into each through hole 43 of the second blank 42, the material 40 can be clamped between the flange surface 312 and the flange surface 322 of the second mold 32. The projections 35 create a gap between the first blank 41 and the second blank 42. The projections 35 are inserted into the through holes 43 of the second blank 42 and lift the first blank 41 from the inside of the material 40. As a result, a gap is created between the first blank 41 and the second blank 42.

[0070] As described above, the tip surface 351 of the projection 35 may be substantially flat. In this case, the projection 35 can make surface contact with the first blank 41 at its tip surface 351. When the first mold 31 and the second mold 32 are closed, the material 40 is first sandwiched between the tip surface 351 of the projection 35 and the relief portion 312a of the flange surface 312 of the first mold 31. This allows the material 40 to be positioned.

[0071] When the first mold 31 and the second mold 32 are closed, the material 40 is held between the sealing portion 33 of the first mold 31 and the sealing portion 33 of the second mold 32. Also, when the first mold 31 and the second mold 32 are closed, the sealing portion 34 (Figure 4) of the first mold 31 abuts against the sealing portion 34 (Figure 4) of the second mold 32. At the location of the sealing portion 33, the material 40 is held more strongly than at other parts of the first mold 31 and the second mold 32.

[0072] Referring to Figures 6E and 6F, in the molding process, the material 40 is held by the first mold 31 and the second mold 32, and fluid is supplied between the first blank 41 and the second blank 42, thereby deforming the material 40 in the hollow space formed by the first mold 31 and the second mold 32. As a result, the first molded product 51 is formed from the first blank 41, and the second molded product 52 is formed from the second blank 42. In this embodiment, after the material 40 is sandwiched between the flange surface 312 of the first mold 31 and the flange surface 322 of the second mold 32, fluid is supplied from the fluid supply port 36 located in the projection 35 into the gap between the first blank 41 and the second blank 42. The fluid is supplied from a fluid supply source (not shown) to the flow path 37, passes through the flow path 37, and flows out from the fluid supply port 36. This fluid causes the material 40 to expand within the hollow space defined by the molding surface 311 of the first mold 31 and the molding surface 321 of the second mold 32.

[0073] The fluid used in the molding process is not particularly limited. The fluid may be a liquid such as water, or a gas such as nitrogen gas or compressed air. The fluid may be a liquid or gas under high pressure, for example, 10 MPa or higher. The temperature of the fluid may be appropriately determined according to the material of the material 40, and may be, for example, room temperature. If a heating process is performed, i.e., when molding is performed by hot stamping, the fluid may be heated.

[0074] Within the hollow space of the mold 30, the first blank 41 of the material 40 is expanded by the fluid and then pressed against the molding surface 311 of the first mold 31. The second blank 42 of the material 40 is expanded by the fluid and then pressed against the molding surface 321 of the second mold 32. As a result, regions 411 and 412 of the material 40 (Figures 6A and 6B) are formed into the shapes of the structural members 10 and 20, respectively. Thus, a first molded product 51 including the first structural member 10 and a second molded product 52 including the second structural member 20 can be obtained.

[0075] If a heating process was performed before the molding process, the first molded product 51 and the second molded product 52 are deheated and hardened by the first mold 31 and the second mold 32, respectively.

[0076] In the molding process, the molding height H1 of the first structural member 10 may be equal to or different from the molding height H2 of the second structural member 20. The molding height H1 is the maximum depth of the molding surface 311 relative to the flange surface 312 in the first mold 31, and is the maximum distance in the processing direction D from the flange surface 312 to the bottom surface of the molding surface 311. The molding height H2 is the maximum depth of the molding surface 321 relative to the flange surface 322 in the second mold 32, and is the maximum distance in the processing direction D from the flange surface 322 to the bottom surface of the molding surface 321. When the molding height H1 of the first structural member 10 and the molding height H2 of the second structural member 20 are different, the difference between the molding heights H1 and H2 is, for example, 1 mm or more. The difference between the molding heights H1 and H2 may be 5 mm or more. The difference between the molding heights H1 and H2 is, for example, 150 mm or less.

[0077] (Trimming process) The manufacturing method according to this embodiment may further include a trimming step. Referring to Figure 6G, in the trimming step, after the molding step, the first molded product 51 and the second molded product 52 are trimmed to obtain separate first structural member 10 and second structural member 20.

[0078] The trimming process may be performed while the first molded product 51 and the second molded product 52 are still inside the mold 30, or it may be performed after the first molded product 51 and the second molded product 52 have been removed from the mold 30. In the trimming process, for example, the outer periphery of the first molded product 51 is removed. More specifically, the portion of the first molded product 51 that was outside the first structural member 10 in the first blank 41 (Figure 6A) is removed. This allows the first structural member 10 to be obtained.

[0079] Similarly, in the trimming process, for example, the outer periphery of the second molded product 52 is removed. More specifically, the portion of the second molded product 52 that was outside the second structural member 20 in the second blank 42 (Figure 6B) is removed. The portion of the second molded product 52 in which the through hole 43 is provided is usually removed in the trimming process. If the first blank 41 and the second blank 42 were joined (temporarily fixed) in the material 40, there is a joint between the first molded product 51 and the second molded product 52, but this joint is removed in the trimming process. This makes it possible to obtain a second structural member 20 that is separate from the first structural member 10. The trimming of the first molded product 51 and the second molded product 52 can be carried out by, for example, laser cutting.

[0080] After the trimming process, the first structural member 10 and the second structural member 20 may each be subjected to a painting process. The first structural member 10 and the second structural member 20 are joined together after undergoing necessary processes such as painting. This allows for the creation of a rear frame for the vehicle body.

[0081] [effect] In the manufacturing method according to this embodiment, a mold 30 is used to mold a material 40 including a first blank 41 and a second blank 42 that are stacked on top of each other. More specifically, the material 40 is held in the first mold 31 and the second mold 32, and a fluid is supplied between the first blank 41 and the second blank 42 to deform the material 40 within the hollow space of the mold 30. As a result, a first molded product 51 including the first structural member 10 is molded from the first blank 41, and a second molded product 52 including the second structural member 20 is molded from the second blank 42. In other words, the first structural member 10 and the second structural member 20 can be molded simultaneously in a single process. Therefore, the number of molding processes can be reduced compared to when the structural members 10 and 20 are molded in separate molding processes, and multiple structural members 10 and 20 can be manufactured productively with fewer processes. In addition, since the number of molds can be reduced compared to when the structural members 10 and 20 are molded in separate molding processes, the cost required for the molds can also be reduced.

[0082] In this embodiment, the clamping force between the first mold 31 and the second mold 32 can seal the periphery of the hollow space of the mold 30. Therefore, even if the first blank 41 and the second blank 42 are not joined in the regions 411 and 412 that will become structural members 10 and 20, the structural members 10 and 20 can be molded using fluid.

[0083] In the manufacturing method according to this embodiment, the first blank 41 and the second blank 42 are not joined in the regions 411 and 421 of the material 40 that will become structural members 10 and 20. That is, in the regions 411 and 421 of the material 40 that will become structural members 10 and 20, the first blank 41 and the second blank 42 are not constrained by a joint. Therefore, when the structural members 10 and 20 are formed by fluid during the molding process, material is more likely to flow into the hollow space of the mold 30, and the structural members 10 and 20 can be formed well. Consequently, even when the molding height H1 of the first structural member 10 and / or the molding height H2 of the second structural member 20 are large, the structural members 10 and 20 can be formed while suppressing the occurrence of molding defects such as cracks and wrinkles. Furthermore, even if the molding height H1 of the first structural member 10 and the molding height H2 of the second structural member 20 are different, it is possible to allow a difference in material inflow corresponding to the difference in molding heights H1 and H2, and the structural members 10 and 20 can be molded while suppressing the occurrence of molding defects.

[0084] In the manufacturing method according to this embodiment, the structural members 10 and 20 are formed in a manner in which no joints exist in at least the regions 411 and 421 of the material 40 that will become the structural members 10 and 20. The structural members 10 and 20 are joined together after the forming process, for example by spot welding. Therefore, no plastic deformation occurs at the joint between the first structural member 10 and the second structural member 20 during the forming process, and the tensile shear strength (TSS) of the joint can be ensured in the structural members 10 and 20 as a rear frame.

[0085] The structural members 10 and 20 manufactured by the manufacturing method according to this embodiment can have various strengths. Depending on the strength of the structural members 10 and 20, cold forming or hot forming (hot stamping) can be selected. Material inflow into the hollow space of the mold 30 is more likely to occur with cold forming than with hot forming, and the formability is better; therefore, when the tensile strength of the structural members 10 and 20 is less than 590 MPa, the forming process is preferably a cold forming process. On the other hand, when the tensile strength of the structural members 10 and 20 is 590 MPa or more, the forming process is preferably a hot forming process because the material 40 is formed while being stretched.

[0086] In the manufacturing method according to this embodiment, the first blank 41 and the second blank 42 are not joined in at least the regions 411 and 421 of the material 40 that will become the first structural member 10 and the second structural member 20. Joining dissimilar metals is generally difficult, but since forming is carried out with the first structural member 10 and the second structural member 20 not joined, structural members 10 and 20 can be formed simultaneously even if they are made of different types of metals. For example, even if one of the structural members 10 and 20 is made of iron plate (steel plate) and the other is made of a non-ferrous metal plate such as an aluminum alloy plate, structural members 10 and 20 can be formed simultaneously.

[0087] In this embodiment, each of the first mold 31 and the second mold 32 is provided with a sealing portion 33. The sealing portion 33 of the first mold 31 and the sealing portion 33 of the second mold 32 are arranged to surround the molding surfaces 311 and 321, respectively. The sealing portion 33 can improve the liquid-tightness or airtightness of the hollow space formed between the molding surfaces 311 and 321. Specifically, when the first mold 31 and the second mold 32 are closed, the sealing portion 33 of the first mold 31 and the sealing portion 33 of the second mold 32 strongly abut and clamp the first blank 41 and the second blank 42, making it difficult for fluid to leak from between the first blank 41 and the second blank 42. Therefore, the molding of structural members 10 and 20 using fluid can be performed more effectively.

[0088] In this embodiment, a sealing portion 34 is further provided in each of the first mold 31 and the second mold 32. This sealing portion 34 allows the mold 30 to seal around the material 40 when the first mold 31 and the second mold 32 are closed. As a result, fluid leakage to the outside of the mold 30 is reduced, and the molding of the structural members 10 and 20 using fluid can be performed even more effectively.

[0089] <Second Embodiment> Figure 7 is a perspective view showing the schematic configuration of structural members 10A and 20A according to this embodiment. Structural members 10A and 20A are front frames for the vehicle body. In this case, structural members 10A and 20A are provided at the front and lower part of the vehicle body, such as an automobile. The first structural member 10A is positioned above the second structural member 20A when incorporated into the vehicle body. The first structural member 10A is the front frame upper, and the second structural member 20A is the front frame lower. However, structural members 10A and 20A may also be subframes for the vehicle body. In this case, structural members 10A and 20A are provided at the front or rear and lower part of the vehicle body. The subframe can have a configuration that is generally similar to that of the front frame.

[0090] In this embodiment, the first structural member 10A includes a pair of side frames 11 and at least one cross member 12, similar to the first structural member 10 in the first embodiment. The first structural member 10A may include a plurality of cross members 12. In the example of Figure 7, the side frames 11 are connected by a cross member 12 at one end in their longitudinal direction. The cross member 12 is positioned, for example, at the rear end of the side frame 11 when the first structural member 10A is assembled to the vehicle body.

[0091] The second structural member 20A, like the second structural member 20 of the first embodiment, includes a pair of side frames 21 and at least one cross member 22. The second structural member 20A may include a plurality of cross members 22. In the example of Figure 7, the side frames 21 are connected by a cross member 22 at one end in their longitudinal direction. The cross member 22 is positioned, for example, at the rear end of the side frame 21 when the second structural member 20A is incorporated into the vehicle body.

[0092] Similar to the first embodiment, with the structural members 10A and 20A assembled to the vehicle body, the first structural member 10A is joined to the second structural member 20A. For example, the side frame 11 of the first structural member 10A is joined to the side frame 21 of the second structural member 20A. Also, for example, the cross member 12 of the first structural member 10A is joined to the cross member 22 of the second structural member 20A.

[0093] The manufacturing method described in the first embodiment can also be applied to the manufacturing of structural members 10A and 20A.

[0094] Referring to Figures 8A and 8B, in this embodiment, a material 40A including a first blank 41A and a second blank 42A is prepared. The basic configuration of the first blank 41A and the second blank 42A is the same as that of the first blank 41 and the second blank 42 (Figures 6A and 6B) used in the manufacturing method according to the first embodiment. However, since the shape of the first structural member 10A (Figure 7) is different from that of the first structural member 10 in the first embodiment, the first blank 41A has a different shape from the first blank 41. Similarly, since the shape of the second structural member 20A (Figure 7) is different from that of the second structural member 20 in the first embodiment, the second blank 42A has a different shape from the second blank 42.

[0095] The first blank 41A includes a region 411A that will become the first structural member 10A (Figure 7) and a region 412A outside the first structural member 10A. The second blank 42A includes a region 421A that will become the second structural member 20A (Figure 7) and a region 422A outside the second structural member 20A. In at least the regions 411A and 421A of the material 40A that will become the first structural member 10A and the second structural member 20A, the first blank 41A and the second blank 42A are not joined. In the regions 412A and 422A of the material 40A outside the structural members 10A and 20A, the first blank 41A and the second blank 42A may be joined (temporarily fixed) by, for example, spot welding.

[0096] Material 40A is subjected to a molding process similar to that of the first embodiment. Material 40A may also be subjected to the molding process after the heating process described above. In the molding process, material 40A is held in the first mold 31 and the second mold 32 (Figures 6C to 6F), and a fluid is supplied between the first blank 41A and the second blank 42A to deform the material 40A in the hollow space formed by the first mold 31 and the second mold 32. As a result, a first molded product is formed from the first blank 41A, and a second molded product is formed from the second blank 42A. The first molded product includes a first structural member 10A (Figure 7). The second molded product includes a second structural member 20A (Figure 7).

[0097] Specifically, as shown in Figures 6C to 6F, similar to the first embodiment, the projection 35 of the second mold 32 is inserted into the through hole 43 of the second blank 42A, and the material 40A (Figures 8A and 8B) is sandwiched between the first mold 31 and the second mold 32, creating a gap between the first blank 41A and the second blank 42A by the projection 35. The first mold 31 and the second mold 32 sandwich the areas 412A and 422A (Figures 8A and 8B) of the material 40A that are outside the structural members 10A and 20A. Then, fluid is injected from the projection 35 into the gap between the first blank 41A and the second blank 42A, and the fluid expands the material 40A within the hollow space of the mold 30. As a result, a first molded product including the first structural member 10A and a second molded product including the second structural member 20A can be obtained.

[0098] Referring to Figure 8C, the first and second molded products may be subjected to a trimming process similar to that of the first embodiment after the molding process. The trimming process may be carried out while the first and second molded products remain in the mold 30 (Figures 6C to 6F), or it may be carried out after the first and second molded products have been removed from the mold 30.

[0099] In the trimming process, the portion of the first blank 41A of the first molded product that was outside the first structural member 10A (region 412A) is removed. Similarly, the portion of the second blank 42A of the second molded product that was outside the second structural member 20A (region 422A) is removed. If the first blank 41A and the second blank 42A were joined (temporarily fixed), a joint would exist in the first and second molded products immediately after the molding process, but this joint is removed in the trimming process. This allows for the production of the first structural member 10A and the second structural member 20A, which is separate from the first structural member 10A.

[0100] After the trimming process, the first structural member 10A and the second structural member 20A may each be subjected to a painting process. The first structural member 10A and the second structural member 20A are joined together after undergoing necessary processes such as painting. This allows for the creation of a front frame for the vehicle body.

[0101] The same effects as in the first embodiment can be achieved when the manufacturing method described in the first embodiment is applied to the manufacturing of structural members 10A and 20A.

[0102] <Third Embodiment> Figure 9 is a perspective view showing the schematic configuration of structural members 10B and 20 according to this embodiment. The first structural member 10B is a member in which the floor panel for the vehicle body and the rear frame upper are integrated. The second structural member 20 is the rear frame lower.

[0103] In this embodiment, the first structural member 10B includes a pair of side frames 11 and at least one cross member 12, similar to the first structural member 10 in the first embodiment. The first structural member 10B may include a plurality of cross members 12. The first structural member 10B further includes a floor panel 13. The floor panel 13 is integrated with the side frames 11 and the cross members 12. The side frames 11 and the cross members 12 have a shape that protrudes from the floor panel 13 on the opposite side of the second structural member 20. The second structural member 20 has the same configuration as the second structural member 20 described in the first embodiment. Similar to the first embodiment, the first structural member 10B is joined to the second structural member 20 when the structural members 10B and 20 are assembled into the vehicle body.

[0104] The manufacturing method described in the first embodiment can also be applied to combinations of structural members 10B and 20.

[0105] Referring to Figures 10A and 10B, in this embodiment, a material 40B including a first blank 41B and a second blank 42 is prepared. The basic configuration of material 40B is the same as that of material 40 (Figures 6A and 6B) used in the manufacturing method according to the first embodiment. However, since the shape of the first structural member 10B (Figure 9) is different from that of the first structural member 10 in the first embodiment, the first blank 41B has a different shape from the first blank 41. The second blank 42 is substantially the same as the second blank 42 in the first embodiment.

[0106] The first blank 41B includes a region 411B that will become the first structural member 10B and a region 412B outside the first structural member 10B. Region 411B includes the portion of the first blank 41B that will be formed into the side frame 11 and the cross member 12 (Figure 9), as well as the portion that will be formed into the floor panel 13 (Figure 9). In the regions 411B and 421 of the material 40B that will become the first structural member 10B and the second structural member 20 (Figure 9), the first blank 41B and the second blank 42 are not joined. In the regions 412B and 422 of the material 40B outside the structural members 10B and 20, the first blank 41B and the second blank 42 may be joined (temporarily fixed) by, for example, spot welding.

[0107] The second blank 42 has a plurality of through holes 43, similar to the first embodiment. In the first embodiment, each through hole 43 is located in the middle of the second blank 42 in the longitudinal direction and at the end in the width direction. In contrast, in this embodiment, each through hole 43 is located at the ends of the second blank 42 in both the longitudinal and width directions. In this embodiment, the through holes 43 are located at the corners (four corners) of the second blank 42. The longitudinal direction of the second blank 42 corresponds to the vehicle length direction of the vehicle body on which the second structural member 20 is provided, and the width direction of the second blank 42 corresponds to the vehicle width direction of the vehicle body on which the second structural member 20 is provided.

[0108] Material 40B is subjected to a molding process similar to that of the first embodiment. Material 40B may also be subjected to the molding process after the heating process described above. In the molding process, material 40B is held in the first mold 31 and the second mold 32 (Figures 6C to 6F), and a fluid is supplied between the first blank 41B and the second blank 42 to deform the material 40B in the hollow space formed by the first mold 31 and the second mold 32. As a result, a first molded product is formed from the first blank 41B, and a second molded product is formed from the second blank 42. The first molded product includes a first structural member 10B (Figure 9). The second molded product includes a second structural member 20 (Figure 9).

[0109] Specifically, as shown in Figures 6C to 6F, similar to the first embodiment, the projection 35 of the second mold 32 is inserted into the through hole 43 of the second blank 42, and the material 40B (Figures 10A and 10B) is sandwiched between the first mold 31 and the second mold 32, creating a gap between the first blank 41B and the second blank 42 by the projection 35. The first mold 31 and the second mold 32 sandwich the areas 412B and 422 (Figures 10A and 10B) of the material 40B that are outside the structural members 10B and 20. Then, fluid is injected from the projection 35 into the gap between the first blank 41B and the second blank 42, and the fluid expands the material 40B in the hollow space of the mold 30. As a result, a first molded product including the first structural member 10B and a second molded product 52 including the second structural member 20 can be obtained.

[0110] Although not shown in the figures, the first and second molded products may be subjected to a trimming process similar to that of the first embodiment after the molding process. The trimming process may be performed while the first and second molded products remain inside the mold 30 (Figures 6C to 6F), or it may be performed after the first and second molded products have been removed from the mold 30.

[0111] In the trimming process, the portion of the first molded product, material 40B that was outside the first structural member 10B (region 412B), is removed. Similarly, the portion of the second molded product, material 40B that was outside the second structural member 20 (region 422), is removed. If the first blank 41B and the second blank 42 were joined (temporarily fixed) in material 40B, a joint will exist in the first and second molded products immediately after the molding process, but this joint is removed in the trimming process. This allows for the production of the first structural member 10B and the second structural member 20, which is separate from the first structural member 10B.

[0112] After the trimming process, the first structural member 10B and the second structural member 20 may each be subjected to a painting process. The first structural member 10B and the second structural member 20 are joined together after undergoing necessary processes such as the painting process.

[0113] Even when the manufacturing method described in the first embodiment is applied to the manufacturing of structural members 10B and 20, the same effects as in the first embodiment can be achieved.

[0114] <Fourth Embodiment> Figure 11 is a perspective view showing the schematic configuration of structural members 10C and 20C according to this embodiment. Structural members 10C and 20C are door rings for a vehicle body. The first structural member 10C is positioned outside the second structural member 20C in the vehicle width direction when assembled into the vehicle body. The first structural member 10C is the door ring outer, and the second structural member 20C is the door ring inner.

[0115] The first structural member 10C may include an A-pillar 14, a B-pillar 15, and a rocker 16. The B-pillar 15 is positioned behind the A-pillar 14 when the first structural member 10C is incorporated into the vehicle body. The A-pillar 14 and B-pillar 15 are connected by the rocker 16. The A-pillar 14, B-pillar 15, and rocker 16 form an annular structure. The first structural member 10C may further include a C-pillar 17. The C-pillar 17 is positioned behind the B-pillar 15 when the first structural member 10C is incorporated into the vehicle body.

[0116] The second structural member 20C may include an A-pillar 24, a B-pillar 25, and a rocker 26. The B-pillar 25 is positioned behind the A-pillar 24 when the second structural member 20C is incorporated into the vehicle body. The A-pillar 24 and B-pillar 25 are connected by the rocker 26. The A-pillar 24, B-pillar 25, and rocker 26 form an annular structure. The second structural member 20C may further include a C-pillar 27. The C-pillar 27 is positioned behind the B-pillar 25 when the second structural member 20C is incorporated into the vehicle body.

[0117] Similar to the first embodiment, with the structural members 10C and 20C incorporated into the vehicle body, the first structural member 10C is joined to the second structural member 20C. For example, the A-pillar 14 of the first structural member 10C is joined to the A-pillar 24 of the second structural member 20C. Also, for example, the B-pillar 15 of the first structural member 10C is joined to the B-pillar 25 of the second structural member 20C. The rocker 16 of the first structural member 10C may be joined to the rocker 26 of the second structural member 20C. If the structural members 10C and 20C each include C-pillars 17 and 27, the C-pillars 17 and 27 may be joined to each other.

[0118] Although not shown in the illustration, the A-pillar 14, B-pillar 15, and rocker 16 of the first structural member 10C may each have a substantially hat-shaped cross-section in at least a portion of it. Similarly, the A-pillar 24, B-pillar 25, and rocker 26 of the second structural member 20C may each have a substantially hat-shaped cross-section in at least a portion of it. The C-pillars 17 and 27 may also have a substantially hat-shaped cross-section in at least a portion of it.

[0119] The manufacturing method described in the first embodiment can also be applied to the manufacturing of structural members 10C and 20C.

[0120] Referring to Figures 12A and 12B, in this embodiment, a material 40C including a first blank 41C and a second blank 42C is prepared. The basic configuration of the first blank 41C and the second blank 42C is the same as that of the first blank 41 and the second blank 42 (Figures 6C and 6B) used in the manufacturing method according to the first embodiment. However, since the shape of the first structural member 10C (Figure 11) is different from that of the first structural member 10 in the first embodiment, the first blank 41C has a different shape from the first blank 41. Similarly, since the shape of the second structural member 20C (Figure 11) is different from that of the second structural member 20 in the first embodiment, the second blank 42C has a different shape from the second blank 42.

[0121] The first blank 41C includes a region 411C that will become the first structural member 10C (Figure 11) and a region 412C outside the first structural member 10C. The second blank 42C includes a region 421C that will become the second structural member 20C (Figure 11) and a region 422C outside the second structural member 20C. In the regions 411C and 421C of the material 40C that will become the first structural member 10C and the second structural member 20C, the first blank 41C and the second blank 42C are not joined. In the regions 412C and 422C of the material 40C outside the structural members 10C and 20C, the first blank 41C and the second blank 42C may be joined (temporarily fixed) by, for example, spot welding.

[0122] Material 40C is subjected to a molding process similar to that of the first embodiment. Material 40C may be subjected to the molding process after the heating process described above. In the molding process, material 40C is held in the first mold 31 and the second mold 32 (Figures 6C to 6F), and a fluid is supplied between the first blank 41C and the second blank 42C to deform the material 40C in the hollow space formed by the first mold 31 and the second mold 32. As a result, a first molded product is formed from the first blank 41C, and a second molded product is formed from the second blank 42C. The first molded product includes a first structural member 10C (Figure 11). The second molded product includes a second structural member 20C (Figure 11).

[0123] Specifically, as shown in Figures 6C to 6F, similar to the first embodiment, the projection 35 of the second mold 32 is inserted into the through hole 43 of the second blank 42C, and the material 40C (Figures 12A and 12B) is sandwiched between the first mold 31 and the second mold 32, creating a gap between the first blank 41C and the second blank 42C by the projection 35. The first mold 31 and the second mold 32 sandwich the regions 412C and 422C (Figures 10A and 10B) of the material 40C that are outside the structural members 10C and 20C. Then, fluid is injected from the projection 35 into the gap between the first blank 41C and the second blank 42C, and the fluid expands the material 40C within the hollow space of the mold 30. As a result, a first molded product including the first structural member 10C and a second molded product including the second structural member 20C can be obtained.

[0124] Although not shown in the figures, the first and second molded products may be subjected to a trimming process similar to that of the first embodiment after the molding process. The trimming process may be performed while the first and second molded products remain inside the mold 30 (Figures 6C to 6F), or it may be performed after the first and second molded products have been removed from the mold 30.

[0125] In the trimming process, the portion of the first molded product that was outside the first structural member 10C (region 412C) in the material 40C is removed. Similarly, the portion of the second molded product that was outside the second structural member 20C (region 422C) in the material 40C is removed. If the first blank 41C and the second blank 42C were joined (temporarily fixed) in the material 40C, a joint will exist in the first and second molded products immediately after the molding process, but this joint is removed in the trimming process. This allows for the production of the first structural member 10C and the second structural member 20C, which is separate from the first structural member 10C.

[0126] After the trimming process, the first structural member 10C and the second structural member 20C may each be subjected to a painting process. The first structural member 10C and the second structural member 20C are joined together after undergoing necessary processes such as painting. This makes it possible to obtain a door ring for a vehicle body.

[0127] The same effects as in the first embodiment can be achieved when the manufacturing method described in the first embodiment is applied to the manufacturing of structural members 10C and 20C.

[0128] <Fifth Embodiment> Figure 13 is a perspective view showing the schematic configuration of structural members 10D and 20D according to this embodiment. The first structural member 10D is a cross member. The second structural member 20D is a lid for a battery case used in a battery unit in the vehicle body. The second structural member 20D may also serve as a floor panel. In this embodiment, a plurality of first structural members 10D are provided on the second structural member 20D.

[0129] Each of the first structural members 10D extends in the vehicle width direction when incorporated into the vehicle body. Each of the first structural members 10D can have the same configuration as the cross member 12 of the first structural member 10 in the first embodiment (Figure 3). Each of the first structural members 10D is positioned on the second structural member 20D and joined to the second structural member 20D.

[0130] The manufacturing method described in the first embodiment can also be applied to the manufacturing of structural members 10D and 20D.

[0131] Referring to Figures 14A and 14B, in this embodiment, a material 40D is prepared that includes a plurality of first blanks 41D and second blanks 42D. The basic configuration of the first blanks 41D and second blanks 42D is the same as that of the first blanks 41 and 2 blanks 42 (Figures 6A and 6B) used in the manufacturing method according to the first embodiment. However, since the shape of the first structural member 10D (Figure 13) is different from that of the first structural member 10 in the first embodiment, the first blank 41D has a different shape from the first blank 41. Similarly, since the shape of the second structural member 20D (Figure 13) is different from that of the second structural member 20 in the first embodiment, the second blank 42D has a different shape from the second blank 42.

[0132] Each of the first blanks 41D includes a region 411D that will become the first structural member 10D and a region 412D outside the first structural member 10D. The second blank 42D includes a region 421D that will become the second structural member 20D and a region 422D outside the second structural member 20D. In at least the regions 411D and 421D of the material 40D that will become the first structural member 10D and the second structural member 20D, the first blank 41D and the second blank 42D are not joined. In the regions 412D and 422D of the material 40D outside the structural members 10D and 20D, the first blank 41D and the second blank 42D may be joined (temporarily fixed) by, for example, spot welding.

[0133] The material 40D is subjected to a molding process similar to that of the first embodiment. The material 40D may be subjected to the molding process after the heating process described above. As shown in Figure 14C, in the molding process, the material 40D is held in the first mold 31 and the second mold 32, and a fluid is supplied between the first blank 41D and the second blank 42D to deform the material 40D in the hollow space formed by the first mold 31 and the second mold 32. As a result, a first molded product 51D is formed from each first blank 41D, and a second molded product 52D is formed from the second blank 42D. The first molded product 51D includes a first structural member 10D. The second molded product 52D includes a second structural member 20D.

[0134] Specifically, as shown in Figures 6C to 6F, similar to the first embodiment, the projection 35 of the second mold 32 is inserted into the through hole 43 of the second blank 42D, and the material 40D (Figure 14C) is sandwiched between the first mold 31 and the second mold 32, with the projection 35 creating a gap between each of the first blank 41D and the second blank 42D. The first mold 31 and the second mold 32 sandwich the regions 412D and 422D (Figures 14A and 14B) of the material 40D that are outside the structural members 10D and 20D. Then, fluid is injected from the projection 35 into the gap between each of the first blank 41D and the second blank 42D, and the fluid expands the material 40D within the hollow space of the mold 30. This makes it possible to obtain a first molded product 51D (Figure 14C) including a first structural member 10D and a second molded product 52D (Figure 14C) including a second structural member 20D.

[0135] Although not shown in the illustration, the first molded product 51D and the second molded product 52D may be subjected to a trimming process similar to that of the first embodiment after the molding process. The trimming process may be carried out while the first molded product 51D and the second molded product 52D are still inside the mold 30, or it may be carried out after the first molded product 51D and the second molded product 52D have been removed from the mold 30.

[0136] In the trimming process, the portion of the first molded product 51D that was outside the first structural member 10D in the material 40D (region 412D) is removed. Similarly, the portion of the second molded product 52D that was outside the second structural member 20D in the material 40D (region 422D) is removed. If the first blank 41D and the second blank 42D were joined (temporarily fixed) in the material 40D, a joint exists between the first molded product 51D and the second molded product 52D, but this joint is removed in the trimming process. This allows for the production of the first structural member 10D and the second structural member 20D, which is separate from the first structural member 10D.

[0137] After the trimming process, the first structural member 10D and the second structural member 20D may each be subjected to a painting process. The first structural member 10D and the second structural member 20D are joined together after undergoing necessary processes such as the painting process.

[0138] The same effects as in the first embodiment can be achieved when the manufacturing method described in the first embodiment is applied to the manufacturing of structural members 10D and 20D.

[0139] <Sixth Embodiment> Figure 15 is a cross-sectional view showing the schematic configuration of structural members 10E and 20E according to this embodiment. Structural members 10E and 20E are battery cases used in the battery unit in the vehicle body. The first structural member 10E is the lid of the battery case. The second structural member 20E may also serve as a floor panel. The second structural member 20E is the main body of the battery case.

[0140] The second structural member 20E has, for example, a tray-like shape with a recess at the bottom. The second structural member 20E has an opening on its upper surface. The first structural member 10E seals the opening of the second structural member 20E. The first structural member 10E is joined to the second structural member 20E.

[0141] The manufacturing method described in the first embodiment can also be applied to the manufacturing of structural members 10E and 20E.

[0142] Referring to Figures 16A and 16B, in this embodiment, a material 40E is prepared, including a first blank 41E and a second blank 42E. The basic configuration of the first blank 41E and the second blank 42E is the same as that of the first blank 41 and the second blank 42 (Figures 6A and 6B) used in the manufacturing method according to the first embodiment. However, since the shape of the first structural member 10E (Figure 15) is different from that of the first structural member 10 in the first embodiment, the first blank 41E has a different shape from the first blank 41. Similarly, since the shape of the second structural member 20E (Figure 15) is different from that of the second structural member 20 in the first embodiment, the second blank 42E has a different shape from the second blank 42.

[0143] The first blank 41E includes a region 411E that will become the first structural member 10E (Figure 15) and a region 412E outside the first structural member 10E. The second blank 42E includes a region 421E that will become the second structural member 20E (Figure 15) and a region 422E outside the second structural member 20E. In the regions 411E and 421E of the material 40E that will become the first structural member 10E and the second structural member 20E, the first blank 41E and the second blank 42E are not joined. In the regions 412E and 422E of the material 40E outside the structural members 10E and 20E, the first blank 41E and the second blank 42E may be joined (temporarily fixed) by, for example, spot welding.

[0144] Similar to the third embodiment, in this embodiment, each through-hole 43 is located at the longitudinal and widthwise ends of the second blank 42E. The through-holes 43 are located at the corners (four corners) of the second blank 42E. The longitudinal direction of the second blank 42E corresponds to the vehicle length direction of the vehicle body on which the second structural member 20E is provided, and the width direction of the second blank 42E corresponds to the vehicle width direction of the vehicle body on which the second structural member 20E is provided.

[0145] The material 40E is subjected to a molding process similar to that of the first embodiment. The material 40E may be subjected to the molding process after the heating process described above. As shown in Figure 16C, in the molding process, the material 40E is held in the first mold 31 and the second mold 32, and a fluid is supplied between the first blank 41E and the second blank 42E, thereby inflating the material 40E in the hollow space formed by the first mold 31 and the second mold 32. This forms the first molded product 51E from the first blank 41E and the second molded product 52E from the second blank 42E. The first molded product 51E includes the first structural member 10E. The second molded product 52E includes the second structural member 20E.

[0146] Specifically, as shown in Figures 6C to 6F, similar to the first embodiment, the projection 35 of the second mold 32 is inserted into the through hole 43 of the second blank 42E, and the material 40E (Figures 16A and 16B) is sandwiched between the first mold 31 and the second mold 32, creating a gap between the first blank 41E and the second blank 42E by the projection 35. The first mold 31 and the second mold 32 sandwich the areas 412E and 422E (Figures 16A and 16B) of the material 40E that are outside the structural members 10E and 20E. Then, fluid is injected from the projection 35 into the gap between the first blank 41E and the second blank 42E, and the fluid expands the material 40E within the hollow space of the mold 30. This makes it possible to obtain a first molded product 51E (Figure 16C) including a first structural member 10E and a second molded product 52E including a second structural member 20E (Figure 16C).

[0147] Although not shown in the illustration, the first molded product 51E and the second molded product 52E may be subjected to a trimming process similar to that of the first embodiment after the molding process. The trimming process may be carried out while the first molded product 51E and the second molded product 52E are still inside the mold 30, or it may be carried out after the first molded product 51E and the second molded product 52E have been removed from the mold 30.

[0148] In the trimming process, the portion of the first molded product 51E that was outside the first structural member 10E in the raw material 40E (region 412E) is removed. Similarly, the portion of the second molded product 52E that was outside the second structural member 20E in the raw material 40E (region 422E) is removed. If the first blank 41E and the second blank 42E were joined (temporarily fixed) in the raw material 40E, a joint exists between the first molded product 51E and the second molded product 52E, but this joint is removed in the trimming process. This allows for the production of the first structural member 10E and the second structural member 20E, which is separate from the first structural member 10E.

[0149] After the trimming process, the first structural member 10E and the second structural member 20E may each be subjected to a painting process. The first structural member 10E and the second structural member 20E are joined together after undergoing necessary processes such as the painting process.

[0150] Even when the manufacturing method described in the first embodiment is applied to the manufacturing of structural members 10E and 20E, the same effects as in the first embodiment can be achieved.

[0151] <Seventh Embodiment> Figure 17 is a cross-sectional view showing an example of structural members 10F and 20F in this embodiment. Figure 18 is a cross-sectional view showing another example of structural members 10F and 20F in this embodiment. Structural members 10F and 20F are members used in a vehicle body, for example, as patch material or bracket parts.

[0152] Referring to Figure 17, the first structural member 10F has, for example, a substantially L-shape in cross-sectional view. The first structural member 10F may include flat plate portions 18 and 19. Flat plate portion 18 is connected to flat plate portion 19 via a bent portion. Similarly, the second structural member 20F has, for example, a substantially L-shape in cross-sectional view. The second structural member 20F may include flat plate portions 28 and 29. Flat plate portion 28 is connected to flat plate portion 29 via a bent portion.

[0153] Referring to Figure 18, the first structural member 10F may also include two flat plate sections 19. In this case, the flat plate sections 19 are connected by a flat plate section 18. Similarly, the second structural member 20F may also include two flat plate sections 29. In this case, the flat plate sections 29 are connected by a flat plate section 28.

[0154] The manufacturing method described in the first embodiment can also be applied to the production of such structural members 10F and 20F. That is, by the manufacturing method described in the first embodiment, multiple first structural members 10F and multiple second structural members 20F can be molded simultaneously.

[0155] Referring to Figures 19A and 19B, in this embodiment, a material 40F is prepared that includes a plurality of first blanks 41F and second blanks 42F. In this embodiment, the material 40F includes the first blank 41F. The basic configuration of the first blank 41F and the second blank 42F is the same as that of the first blank 41 and the second blank 42 (Figures 6A and 6B) used in the manufacturing method according to the first embodiment. However, since the shape of the first structural member 10F (Figures 17 and 18) is different from that of the first structural member 10 in the first embodiment, the first blank 41F has a different shape from the first blank 41. Similarly, since the shape of the second structural member 20F (Figures 17 and 18) is different from that of the second structural member 20 in the first embodiment, the second blank 42F has a different shape from the second blank 42.

[0156] Each of the first blanks 41F includes a region 411F that will become the first structural member 10F (Figures 17 and 18) and a region 412F outside the first structural member 10F. The second blank 42F includes a region 421F that will become the second structural member 20F (Figures 17 and 18) and a region 422F outside the second structural member 20F. The second blank 42F has multiple regions 421F corresponding to multiple second structural members 20F. In this embodiment, a first blank 41F is prepared for each first structural member 10F, while a common second blank 42F is prepared for multiple second structural members 20F.

[0157] In the regions 411F and 421F of the material 40F that will become at least the first structural member 10F and the second structural member 20F, the first blank 41F and the second blank 42F are not joined. In the regions 412F and 422F of the material 40F that are outside the structural members 10F and 20F, the first blank 41F and the second blank 42F may be joined (temporarily fixed) by, for example, spot welding.

[0158] The material 40F is subjected to a molding process similar to that of the first embodiment. The material 40F may be subjected to the molding process after the heating process described above. As shown in Figure 19C, in the molding process, the material 40F is held in the first mold 31 and the second mold 32, and a fluid is supplied between the first blank 41F and the second blank 42F to deform the material 40F in the hollow space formed by the first mold 31 and the second mold 32. As a result, a first molded product 51F is formed from each of the first blanks 41F, and a second molded product 52F is formed from the second blank 42F. Each of the first molded products 51F contains a first structural member 10F. The second molded product 52F contains a plurality of second structural members 20F.

[0159] Specifically, as shown in Figures 6C to 6F, similar to the first embodiment, the projection 35 of the second mold 32 is inserted into the through hole 43 of the second blank 42F, and the material 40F (Figures 19A and 19B) is sandwiched between the first mold 31 and the second mold 32, with the projection 35 creating a gap between each of the first blank 41F and the second blank 42F. The first mold 31 and the second mold 32 sandwich the regions 412F and 422F (Figures 19A and 19B) of the material 40F that are outside the structural members 10F and 20F. Then, fluid is injected from the projection 35 into the gap between each of the first blank 41F and the second blank 42F, and the fluid expands the material 40F within the hollow space of the mold 30. This makes it possible to obtain a first molded product 51F (Figure 19C) including a first structural member 10F and a second molded product 52F (Figure 19C) including a second structural member 20F.

[0160] Multiple first molded products 51F and second molded products 52F may be subjected to a trimming process similar to that in the first embodiment after the molding process. The trimming process may be carried out while the first molded products 51F and second molded products 52F remain inside the mold 30, or it may be carried out after the first molded products 51F and second molded products 52F have been removed from the mold 30.

[0161] In the trimming process, the portion of each first molded product 51F that was outside the first structural member 10F in the raw material 40F (region 412F) is removed. From each first molded product 51F, the first structural member 10F with the shape shown in Figure 17 or Figure 18 is obtained. In addition, the portion of the second molded product 52F that was outside the second structural member 20F in the raw material 40F (region 422F) is removed. From the second molded product 52F, multiple second structural members 20F with the shape shown in Figure 17 or Figure 18 are obtained.

[0162] If the first blank 41F and the second blank 42F are joined (temporarily fixed) in material 40F, a joint exists in the first molded product 51F and the second molded product 52F, but this joint is removed in the trimming process. As a result, multiple first structural members 10F and multiple second structural members 20F, which are separate from the first structural member 10F, can be obtained.

[0163] After the trimming process, the first structural member 10F and the second structural member 20F may each be subjected to a painting process. After undergoing necessary processes such as the painting process, the first structural member 10F and the second structural member 20F are joined to a predetermined member.

[0164] The same effects as in the first embodiment can be achieved when the manufacturing method described in the first embodiment is applied to the manufacturing of structural members 10F and 20F.

[0165] In this embodiment, a first blank 41F is prepared for each first structural member 10F, while a common second blank 42F is prepared for multiple second structural members 20F. When multiple second structural members 20F are formed from a common second blank 42F, the material flow is restricted compared to when each first structural member 10F is formed from a separate first blank 41F. Therefore, it is preferable that the molding height H2 of the second structural member 20F is smaller than the molding height H1 of the first structural member 10F.

[0166] <Eighth Embodiment> The manufacturing method according to each embodiment may also use the mold 30A shown in Figure 20. Figure 20 is a cross-sectional view of the mold 30A. In this embodiment, an example of the mold 30A for manufacturing the structural members 10,20 of the first embodiment is described. However, the mold 30A can also be applied to the manufacturing of structural members of other embodiments.

[0167] Referring to Figure 20, mold 30A differs from mold 30 of other embodiments (Figure 4) in that it is provided with a positioning pin 38. In mold 30A, one of the first mold 31A and the second mold 32A includes the positioning pin 38. The other of the first mold 31A and the second mold 32A includes a recess 39.

[0168] In this embodiment, the second mold 32A includes a positioning pin 38. The positioning pin 38 is provided on the surface of the second mold 32A facing the first mold 31A. The positioning pin 38 protrudes from this surface toward the first mold 31A. The positioning pin 38 may also be provided on the flange surface 322.

[0169] On the other hand, the first mold 31A includes a recess 39. The recess 39 is located on the surface of the first mold 31A facing the second mold 32A, at a position corresponding to the positioning pin 38. The recess 39 may also be provided on the flange surface 312.

[0170] Figure 20 partially shows the longitudinal section of the mold 30A passing through the center of gravity of the molding surface 321 of the second mold 32A and the fluid supply port 36. The center of gravity of the molding surface 321 refers to the center of gravity of the shape when the molding surface 321 is projected in the processing direction D. Looking at the longitudinal section of the mold 30A passing through the center of gravity of the molding surface 321 and the fluid supply port 36, the positioning pin 38 is positioned outside the molding surface 321 beyond the fluid supply port 36. The seal portion 33 of the second mold 32A includes the portion passing between the fluid supply port 36 and the positioning pin 38.

[0171] Referring to Figures 21A and 21B, it is preferable to use the mold 30A when the first blank 41 and the second blank 42 are not joined at all in the material 40. In this case, a notch 44 is provided at the edge of the portion of the material 40 where the first blank 41 and the second blank 42 overlap. During the molding process, a positioning pin 38 is placed in the notch 44 of the material 40. This makes it less likely for the first blank 41 and the second blank 42 to be misaligned, even when they are not joined (temporarily fixed) and are independent. The positioning pin 38 is housed in the recess 39 when the first mold 31A and the second mold 32A are closed.

[0172] After the molding process, the first molded product 51 formed from the first blank 41 and the second molded product 52 formed from the second blank 42 are discharged from the mold 30A. The first molded product 51 and the second molded product 52 may be discharged individually from the mold 30A, or they may be discharged simultaneously. When the first molded product 51 and the second molded product 52 are discharged simultaneously from the mold 30A, the lower mold of the first mold 31A and the second mold 32A may be provided with a recess for inserting, for example, an arm of a transport mechanism.

[0173] For example, by providing a recess in the flange surface 322 of the second mold 32, the arm of the transport mechanism can be inserted below the second molded product 52 and the arm can grip the second molded product 52. The first molded product 51 may be removed from the mold 30A together with the second molded product 52 while it is placed on top of the second molded product 52, or it may be removed from the mold 30A while being gripped together with the second molded product 52. If a trimming process is performed in the mold 30A, both structural members 10 and 20 (Figure 6F) after the trimming process may be gripped by the arm of the transport mechanism, etc., and removed from the mold 30A at the same time, or the structural members 10 and 20 may be removed from the mold 30A separately.

[0174] While embodiments relating to this disclosure have been described above, this disclosure is not limited to the embodiments described above, and various modifications are possible as long as they do not deviate from its spirit.

[0175] In the embodiments described above, examples were given in which a projection 35 having a fluid supply port 36 is provided on the second mold 32, 32A. However, the projection 35 may also be provided on the first mold 31, 31A. The projection 35 only needs to be provided in the first mold 31, 31A or the second mold 32, 32A at a position that can supply fluid to the hollow space of the mold 30, 30A. When the projection 35 is provided on the first mold 31, 31A, the through holes 43 are formed in the first blanks 41, 41A, 41F, respectively, in the materials 40, 40A to 40F.

[0176] In the embodiments described above, examples were given in which the second molds 32, 32A are positioned below the first molds 31, 31A. However, the positional relationship between the first molds 31, 31A and the second molds 32, 32A is not limited thereto. When manufacturing structural members 10, 10A~10F, 20, 20A, 20C~20F, the second molds 32, 32A may be positioned above the first molds 31, 31A, for example. The projection 35 may be provided on the mold positioned below the first molds 31, 31A and the second molds 32, 32A, or on the mold positioned above. When the upper of the first molds 31, 31A and the second molds 32, 32A is provided with a projection 35, the materials 40, 40A to 40F are not placed on the projection 35 during the molding process, so the materials 40, 40A to 40F can be stably positioned before the molds 31, 31A and the second molds 32, 32A are closed. Therefore, it is not necessary to provide a flat tip surface 351 on the projection 35 for positioning the materials 40, 40A to 40F.

[0177] In each of the above embodiments, sealing portions 33 and 34 are provided in both the first mold 31, 31A and the second mold 32, 32A. However, the sealing portions 33 and / or 34 may not be provided in either the first mold 31, 31A or the second mold 32, 32A, and the sealing portions 33 and 34 may not be provided in either the first mold 31, 31A or the second mold 32, 32A. However, from the viewpoint of preventing fluid leakage, it is preferable that at least the sealing portions 33 are provided in both the first mold 31, 31A and the second mold 32, 32A. More preferably, the sealing portions 33 and 34 are provided in a double configuration in both the first mold 31, 31A and the second mold 32, 32A.

[0178] In each of the above embodiments, a gap is created between the first blank 41 and each of the second blanks 42 by projections 35 provided on the molds 30 and 30A, thereby securing a fluid passage. However, the molds 30 and 30A do not necessarily have projections 35. In the molding process, with the material 40, 40A to 40F held between the first blanks 41, 41A to 41F and the second blanks 42, 42A, 42C to 42F, fluid is supplied, and the material 40, 40A to 40F is deformed within the hollow space of the molds 30 and 30A by this fluid, thereby forming the first and second molded products. For example, fluid can also be supplied into the hollow space at positions within the material 40, 40A to 40F that will become the first structural members 10, 10A to 10F or the second structural members 20, 20A, 20C to 20F.

[0179] In the embodiments described above, examples were given in which a trimming process is performed after the molding process. However, the manufacturing methods according to each embodiment do not necessarily include a trimming process. For example, if the first molded product formed in the molding process becomes the first structural members 10, 10A to 10F as is, trimming of the first molded product is unnecessary. Similarly, if the second molded product formed in the molding process becomes the second structural members 20, 20A, 20C to 20F as is, trimming of the second molded product is unnecessary.

[0180] The manufacturing method described herein is not limited to the application of the first structural members 10, 10A to 10F and the second structural members 20, 20A, 20C to 20F described in each embodiment. The manufacturing method can be applied to the manufacture of various structural members. [Explanation of symbols]

[0181] 10, 10A, 10B, 10C, 10D, 10E, 10F: First structural member 20, 20A, 20C, 20D, 20E, 20F: Second structural member 30,30A: Mold 31,31A: First mold 311: Molding surface 312: Flange surface 32,32A: Second mold 321: Molding surface 322: Flange surface 33,34: Seal part 36:Fluid supply port 38: Positioning pin 39: Recess 40, 40A, 40B, 40C, 40D, 40E, 40F: Material 41, 41A, 41B, 41C, 41D, 41E, 41F: First blank 42, 42A, 42C, 42D, 42E, 42F: Second blank 51,51D,51E,51F: 1st molded product 52,52D,52E,52F: 2nd molded product

Claims

1. A manufacturing method for producing a first structural member and a second structural member separate from the first structural member, A step of preparing a material comprising a first blank and a second blank superimposed on the first blank, wherein in the regions of the material that become the first structural member and the second structural member, the first blank and the second blank are not joined together. A step of forming a first molded product including the first structural member from the first blank and a second mold, by holding the material in a first mold and a second mold and supplying fluid between the first blank and the second blank, thereby deforming the material in the hollow space formed by the first mold and the second mold, and forming a second molded product including the second structural member from the second blank, A manufacturing method that includes the following features.

2. A manufacturing method according to claim 1, A manufacturing method comprising the molding step of which a first molded product including the first structural member and a second molded product including the second structural member having a different shape from the first structural member are molded.

3. A manufacturing method according to claim 2, A manufacturing method wherein, in the molding process, the molding height of the first structural member is different from the molding height of the second structural member.

4. The manufacturing method according to claim 1, further, A manufacturing method comprising the step of trimming the first molded product and the second molded product after the molding step to obtain the first structural member and the second structural member.

5. It is a mold, The system comprises a first mold and a second mold, each including a molding surface and a flange surface arranged around the molding surface, One of the first mold and the second mold includes a fluid supply port formed on the surface facing the other of the first mold and the second mold, and a positioning pin provided on the surface and positioned outside the fluid supply port of the molding surface when viewed in a longitudinal cross-section passing through the center of gravity of the molding surface and the center of the fluid supply port, A mold in which the other of the first mold and the second mold includes a recess formed on the surface facing one of the first mold and the second mold at a position corresponding to the positioning pin.

6. A mold according to claim 5, One of the first mold and the second mold includes a convex sealing portion provided on the surface facing the other of the first mold and the second mold, which surrounds the molding surface. The mold includes a portion of the sealing area that is positioned between the fluid supply port and the positioning pin.

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