Coupling structure of vehicle body structure members

Abstract

To provide a coupling structure of vehicle body structure members which has been improved to be adaptable to a vehicle body structure using a fiber-reinforced resin composite material.SOLUTION: A coupling structure of vehicle body structure members that couples a first member extending in a first direction and a second member extending in a second direction intersecting the first direction, wherein at least one of the first member and the second member is made of a fiber-reinforced resin composite material. The first member has a solid first fitting portion having predetermined rigidity, and the second member has a solid second fitting portion having predetermined rigidity. The first fitting portion and the second fitting portion are fitted to each other so that the first member and the second member are coupled. One of the first fitting portion and the second fitting portion has a cylindrical or semi-cylindrical tubular portion having an axis along the second direction, and the other of the first fitting portion and the second fitting portion has a cylindrical or semi-cylindrical inner peripheral surface in contact with the outer peripheral surface of the tubular portion.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology of the present disclosure relates to a joining structure of a vehicle body structural member using a fiber-reinforced resin composite material. [Background technology]

[0002] With the aim of reducing the weight of vehicle bodies, development is underway for vehicle body structures made of composite materials using fiber-reinforced resins, typified by carbon fiber-reinforced resins (hereinafter also referred to as "fiber-reinforced resin composites"). Fiber-reinforced resin composites have high rigidity, and demonstrate high strength, particularly against tensile stress acting along the fiber orientation direction. When constructing a vehicle body structure using fiber-reinforced resin composites, a monocoque structure is generally used.

[0003] As an example of a vehicle body structure using a fiber-reinforced resin composite, Patent Document 1 discloses a tubular frame for a mobile body that includes a first pipe section and a second pipe section connected to the first pipe section via a connecting section, wherein the connecting section is a first connecting section that is tubular and has a first slit, and is arranged on a side surface so that a first opening of the first slit intersects with the axial direction of the first connecting section, and a second connecting section that is tubular and has substantially the same cross-sectional shape as the first connecting section and has a second slit, and is arranged on a side surface so that a second opening of the second slit intersects with the axial direction of the second connecting section, and the first pipe section and the second pipe section are connected by the first connecting section and the second connecting section engaging with each other via the first slit and the second slit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-75066 Summary of the Invention [Problem to be solved by the invention]

[0005] However, while Patent Document 1 describes that multiple pipe sections may be formed from fiber-reinforced resin, it does not specifically disclose how to ensure strength when connecting by engaging slits between fiber-reinforced resin pipe sections. Joining fiber-reinforced resin components is not suitable for mass production because the strength and deformation mode differ depending on the fiber orientation direction of the components. In response to this, a possible configuration is to join the components using a joining member machined from a solid member such as solid metal. However, with such a joining member, it is difficult to control the deformation mode of the joint between the solid member and the fiber-reinforced resin member, and the strength of the joint may be unstable.

[0006] Therefore, the technology of the present disclosure has been made in consideration of the above problems, and an object of the present disclosure is to provide an improved joining structure of vehicle body structural members that can be applied to vehicle body structures using fiber-reinforced resin composite materials. [Means for solving the problem]

[0007] In order to solve the above problem, there is provided a connection structure for a vehicle body structural member that connects a first member, at least one of which is made of a fiber-reinforced resin composite material and extends along a first direction, and a second member that extends along a second direction intersecting the first direction, wherein the first member has a solid first fitting portion having a predetermined rigidity, and the second member has a solid second fitting portion having a predetermined rigidity, the first member and the second member are connected by being fitted together with each other, one of the first fitting portion and the second fitting portion has a cylindrical or semi-cylindrical tubular portion having an axis along the second direction, and the other of the first fitting portion and the second fitting portion has a cylindrical or semi-cylindrical inner circumferential surface that contacts the outer circumferential surface of the tubular portion. [Effects of the Invention]

[0008] As described above, the technique of the present disclosure can provide an improved connection structure for vehicle body structural members that can be applied to vehicle body structures that use fiber-reinforced resin composite materials. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing a joining structure of a vehicle body structural member according to an embodiment of the present disclosure; [Figure 2] 1 is an exploded perspective view showing the joining structure of the vehicle body structural member according to the embodiment. [Figure 3] 2 is a schematic view of the connection structure of the vehicle body structural member shown in FIG. 1, viewed along a second direction. [Figure 4] 2 is a schematic diagram showing how the joint structure of the body structural member shown in FIG. 1 breaks. FIG. [Figure 5] 10 is a schematic view of a modified example of a joining structure of a vehicle body structural member as viewed along a second direction. FIG. [Figure 6] 6 is a schematic diagram showing how the joint structure of the body structural member shown in FIG. 5 breaks. FIG. [Figure 7] FIG. 10 is a schematic view of a connecting structure of a vehicle body structural member according to another modified example, viewed along a second direction. [Figure 8] 8 is a schematic diagram showing how the joint structure of the body structural member shown in FIG. 7 breaks. FIG. [Figure 9] 5 is an explanatory view showing an example of a method for manufacturing a second member used in the joining structure of vehicle body structural members according to the embodiment. FIG. [Figure 10] 10 is an explanatory view showing a method for joining a first member and a second member according to the embodiment. [Figure 11] 10 is an explanatory view showing a method for joining a first member and a second member according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the technology of the present disclosure will be described in detail below with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0011] <1. Joint structure of body structural members> First, a joining structure of a vehicle body structural member according to an embodiment of the present disclosure will be described. Figures 1 and 2 are explanatory diagrams showing the connection structure of a vehicle body structural member according to this embodiment. Figure 1 is a perspective view showing the connection structure of a vehicle body structural member, and Figure 2 is an exploded perspective view showing the connection structure of a vehicle body structural member.

[0012] The joining structure 10 for vehicle body structural members is a structure that joins a first member 30, at least one of which is made of a fiber-reinforced resin composite material and extending along a first direction D1, to a second member 20 that extends along a second direction D2 that intersects with the first direction D1. The present disclosure is characterized by the structure that joins the first member 30 and the second member 20, and the shapes of the first member 30 and the second member 20 are not limited to the examples shown in the drawings, and may have any shape.

[0013] The joining structure joining a first member 30 extending along a first direction D1 and a second member 20 extending along a second direction D2 intersecting the first direction D1 can be applied, for example, to a structure joining a center pillar extending along the vehicle body height direction as the first member 30 and a side sill extending in the vehicle front-rear direction as the second member 20. However, the joining portion to which the joining structure of vehicle body structural members can be applied is not limited to the joining portion between the center pillar and the side sill, but may be applied to other joining portions, such as a joining portion between a front pillar or a rear pillar extending along the vehicle body height direction (D1) and a side sill extending along the vehicle body front-rear direction (D2), a joining portion between a front pillar, center pillar, or rear pillar extending along the vehicle body height direction (D1) and a roof rail extending along the vehicle body front-rear direction (D2), or a joining portion between a cross member extending along the vehicle width direction (D3) and a side rail or side sill extending along the vehicle body front-rear direction (D2).

[0014] In this embodiment, the first member 30 has a core material 33 made of a porous material, a surface layer material 31 made of a fiber-reinforced resin that covers all or part of the core material 33, and a first fitting portion 35 that is formed in part of the core material 33 and has pores in the porous material filled with a filler material that has been hardened. The second member 20 has a core material 23 made of a porous material, a surface layer material 21 made of a fiber-reinforced resin that covers all or part of the core material 23, and a second fitting portion 25 that is formed in part of the core material 23 and has pores in the porous material filled with a filler material that has been hardened.

[0015] The first fitting portion 35 and the second fitting portion 25 each have a predetermined rigidity, and the first member 30 and the second member 20 are joined together by fitting the first fitting portion 35 and the second fitting portion 25 together. The covering layer 41 is arranged so as to cover the periphery of the first fitting portion 35 and the second fitting portion 25 that join the first member 30 and the second member 20 together.

[0016] The porous core materials 23, 33 have a honeycomb or porous structure made of metal such as aluminum or resin, or a porous structure made of compressed fibers, and are lightweight while providing the desired rigidity. When using a porous material with a porous structure, it is preferable that the pores are connected to each other. This is because it is advantageous in that the first fitting portion 35 and the second fitting portion 25 can be filled with a filler to form a solid core.

[0017] The surface layer materials 21, 31 are made of fiber-reinforced resin. The surface layer materials 21, 31 may be formed by laminating prepreg sheets, in which fibers are mixed with a matrix resin, around the core materials 23, 33 (layup), or by winding continuous fibers impregnated with a matrix resin around the core materials 23, 33. The surface layer material 21 includes continuous fibers oriented, for example, at angles of 0 degrees, ±45 degrees, and ±90 degrees relative to the extension direction of the first member 30 and the second member 20, respectively. The orientation angle and ratio of the continuous fibers are appropriately designed depending on the rigidity characteristics required of the member.

[0018] In this embodiment, the surface layer materials 21, 31 are formed using a fiber-reinforced resin in which carbon fiber is impregnated with a thermoplastic resin or a thermosetting resin as a matrix resin. Examples of thermoplastic resins include polyethylene resin, polypropylene resin, polyvinyl chloride resin, ABS resin (acrylonitrile-butadiene-styrene copolymer synthetic resin), polystyrene resin, AS resin (acrylonitrile-styrene copolymer synthetic resin), polyamide resin, polyacetal resin, polycarbonate resin, polyester resin, PPS (polyphenylene sulfide) resin, fluororesin, polyetherimide resin, polyetherketone resin, and polyimide resin.

[0019] The thermoplastic resin may be one of the above resins or a mixture of two or more of them. Alternatively, the thermoplastic resin may be a copolymer of the above resins. When the thermoplastic resin is a mixture, a compatibilizer may be used in combination. Furthermore, a flame retardant such as a bromine-based flame retardant, a silicon-based flame retardant, or red phosphorus may be added to the thermoplastic resin.

[0020] Examples of thermosetting resins include epoxy resins, unsaturated polyester resins, vinyl ester resins, phenolic resins, polyurethane resins, and silicone resins. The thermosetting resin may be one of the above resins or a mixture of two or more of them. An appropriate curing agent or reaction accelerator may be added to the thermosetting resin.

[0021] The covering layer 41 has a similar configuration to the surface layer materials 21, 31. Although Fig. 2 shows the covering layer 41 in sheet form wrapped around the first fitting portion 35 and the second fitting portion 25, the method for forming the covering layer 41 is not limited to the example of wrapping a sheet of fiber-reinforced resin, and the covering layer 41 may be formed by any method. It is preferable that the fibers are arranged continuously in the circumferential direction, but as shown in Fig. 2, the fibers do not have to be connected in the circumferential direction.

[0022] The first fitting portion 35 and the second fitting portion 25 are formed in part of the core material 23, 33 made of a porous material, and have a solidified configuration in which a filler material is filled into the pores of the porous material and hardened. The first fitting portion 35 and the second fitting portion 25 have higher rigidity than the core material 23, 33 that is not solidified. The filler material includes at least a thermosetting resin or a thermoplastic resin. The thermosetting resin or thermoplastic resin is not particularly limited as long as it can be hardened. The filler material preferably includes a filler such as short fibers made by chopping fibers into short pieces. By including short fibers in the filler material, an increase in the weight of the first fitting portion 35 and the second fitting portion 25 can be suppressed.

[0023] The first member 30 and the second member 20 are mechanically coupled by a fitting structure or an engagement structure in which the first fitting portion 35 and the second fitting portion 25 fit together. One of the first fitting portion 35 and the second fitting portion 25 has a cylindrical or semi-cylindrical tubular portion 37 having an axis along the second direction D2 in which the second member 20 extends, and the other of the first fitting portion 35 and the second fitting portion 25 has a cylindrical or semi-cylindrical inner circumferential surface 27 that contacts the outer circumferential surface of the tubular portion 37. In this embodiment, the first fitting portion 35 has a cylindrical or semi-cylindrical tubular portion 37 having an axis along the second direction D2, and the second fitting portion 25 has a cylindrical or semi-cylindrical inner circumferential surface 27 that contacts the outer circumferential surface of the tubular portion 37.

[0024] Due to this configuration, the connection structure 10 between the first member 30 and the second member 20 has anisotropy in the strength of the connection portion. The cylindrical first fitting portion 35 and the second fitting portion 25, each having an axis along the extension direction of the second member 20 (second direction D2), are fitted together, so that when a load is input from a third direction that intersects both the first direction D1 and the second direction D2, the first member 30 and the second member 20 are likely to rotate about their respective cylindrical first fitting portion 35 and second fitting portion 25. Therefore, when the connection structure for a vehicle body structural member according to this embodiment is applied to a connection portion between a center pillar and a side sill, for example, the direction of deformation of the connection portion during a side collision can be controlled.

[0025] In this embodiment, the first fitting portion 35 and the second fitting portion 25 have a first retaining structure that prevents the first member 30 and the second member 20 from separating in the first direction D1. For example, the first fitting portion 35 includes a tubular portion 37 and a neck portion 39 that has a width smaller than the diameter of the tubular portion 37 and extends along the first direction D1, connecting the tubular portion 37 to the non-solid core material 33. The second fitting portion 25 also includes a space having a shape substantially identical to the three-dimensional shape of the first fitting portion 35. Therefore, the tubular portion 37 of the first fitting portion 35 can move within the space of the second fitting portion 25 in the second direction D2 but cannot move in the first direction D1. This prevents the first member 30 and the second member 20 from separating in the first direction D1.

[0026] Furthermore, the joining structure 10 for a vehicle body structural member may have a second retaining structure that prevents the first member 30 and the second member 20 from separating in the second direction D2. For example, in this embodiment, a coating layer 41 is arranged to cover the periphery of the first fitted portion 35 and the second fitted portion 25 where the first member 30 and the second member 20 are joined. Therefore, the tubular portion 37 of the first fitted portion 35 cannot move in the second direction D2 within the space of the second fitted portion 25, and it is possible to prevent the first member 30 and the second member 20 from separating in the first direction D1.

[0027] In the illustrated example, the first fitting portion 35 of the first member 30 consists of a solid portion including a tubular portion 37, and the second fitting portion 25 of the second member 20 consists of a space that fits into the first fitting portion 35, but the second fitting portion 25 of the second member 20 may also consist of a solid portion including a tubular portion, and the first fitting portion 35 of the first member 30 may also consist of a space that fits into the second fitting portion 25.

[0028] Furthermore, the structure in which the first fitting portion 35 and the second fitting portion 25 fit together may be, for example, a wooden framework. A wooden framework is a joining structure in which each of the members to be joined is machined and fitted together. With a wooden framework, the first member 30 and the second member 20 can be firmly joined together without using fasteners such as metal bolts. An adhesive may be placed in the gap between the first fitting portion 35 and the second fitting portion 25.

[0029] Furthermore, the mating portion between the first mating portion 35 and the second mating portion 25 may have at least one of a friction-increasing portion, an adhesive layer, and a gap to reduce the vibration response of lower vibration modes of the vehicle body frame. For example, the contact surface between the first member 30 and the second member 20 at the mating portion between the first mating portion 35 and the second mating portion 25 may be roughened to increase friction, an adhesive may be filled between the first member 30 and the second member 20, or a gap may be provided between the first member 30 and the second member 20. For example, the greater the friction at the contact surface between the first member 30 and the second member 20, the greater the rigidity of the joint portion. Furthermore, the larger the gap between the first member 30 and the second member 20, the lower the rigidity of the joint portion. Furthermore, the greater the rigidity of the adhesive filled in the gap, the greater the rigidity of the joint portion. In this way, the vibration response of vibration modes, particularly to stress applied in the vehicle body width direction or to moments generated around the axis of the second member 20, can be controlled.

[0030] FIG. 3 is a schematic diagram of the connection structure 10 for vehicle body structural members shown in FIG. 1 as viewed along the second direction D2. The left side of the illustration is the exterior of the vehicle body, and the right side is the interior side. In the illustrated example, the outer peripheral surface of the tubular portion 37 of the first fitting portion 35 and the inner peripheral surface 27 of the second fitting portion 25 serve as abutting surfaces (contact surfaces). Gaps 55 and 57 are provided between the exterior surface of the neck portion 39 of the first fitting portion 35 and the interior side surface of the second fitting portion 25, respectively. Of the facing portions of the first member 30 and the second member 20 facing in the first direction D1, a gap is provided in a facing portion 51 on the exterior of the vehicle body, and adhesive 59 is filled in the gap. Of the facing portions of the first member 30 and the second member 20 facing in the first direction D1, a facing portion 53 on the interior side serves as abutting surfaces (contact surfaces).

[0031] 3, a gap is provided in the facing portion 51 on the vehicle body exterior, and the gap is filled with adhesive 59, while the facing portion 53 on the vehicle interior side serves as the abutment surface (contact surface), so that the strength of the joined portion against stress from the vehicle body exterior is lower than the strength of the joined portion against stress from the vehicle interior side. Therefore, while deformation due to a load input from the vehicle interior side can be suppressed, when a collision load is input from the vehicle body exterior, the joined portion can be deformed to absorb collision energy (see FIG. 4).

[0032] 3 is merely an example. For example, the outer peripheral surface of the tubular portion 37 of the first fitting portion 35, the inner peripheral surface 27 of the second fitting portion 25, and the opposing portion 53 on the passenger compartment side, which are abutting surfaces (contact surfaces), may be roughened to increase frictional force. Furthermore, adhesive may be filled in gaps 55, 57 between the outer surface of the neck portion 39 of the first fitting portion 35 facing the vehicle body and the inner surface of the space portion of the second fitting portion 25 on the passenger compartment side. Furthermore, the outer surface of the neck portion 39 of the first fitting portion 35 facing the vehicle body and the inner surface of the space portion of the second fitting portion 25 on the passenger compartment side may each be abutting surfaces (contact surfaces). In this case, the abutting surfaces (contact surfaces) may be roughened to increase frictional force. In addition, by providing a frictional force increasing portion, an adhesive layer, and a gap in an appropriate area between the first mating portion 35 of the first member 30 and the second mating portion 25 of the second member 20, the vibration mode or bending mode of the joint portion can be controlled.

[0033] Furthermore, the connection structure 10 for a vehicle body structural member can also control the folding mode of the connection portion when a collision load is input during a side collision by using the shapes of the first fitting portion 35 and the second fitting portion 25. Fig. 5 shows a modified example of the connection structure 10 for a vehicle body structural member. In the modified example shown in Fig. 5, facing portions 51, 53 where the first member 30 and the second member 20 face each other in the first direction D1 are formed as arc surfaces concentric with the tubular portion 37 of the first fitting portion 35. This makes it easier to deform when a collision load is input from outside the vehicle body compared to the configuration shown in Fig. 3 (see Fig. 6).

[0034] 7 shows another modified example of the joining structure 10 for a vehicle body structural member. In the modified example shown in FIG. 7, the second fitting portion 25 of the second member 20 has a tubular portion 28 provided with its center offset toward the outside of the vehicle body, and an arc-shaped engagement groove 29 provided adjacent to the tubular portion 28 on the passenger compartment side. The first fitting portion 35 of the first member 30 has a tubular inner peripheral surface 38 that contacts the outer peripheral surface of the tubular portion 28 of the second fitting portion 25, and an arc-shaped protruding portion 36 that is inserted into the engagement groove 29 of the second fitting portion 25. According to the configuration shown in FIG. 7, when stress is applied from the passenger compartment side, the protruding portion 36 of the first fitting portion 35 abuts against the deepest portion of the engagement groove 29 of the second fitting portion 25, making it less likely to break. On the other hand, when a collision load is input from outside the vehicle body, the inner surface 38 of the first fitting portion 35 and the outer surface of the tubular portion 28 of the second fitting portion 25 slide against each other, allowing the first member 30 and the second member 20 to rotate relative to each other, making it easier to deform than the configuration shown in Figure 3 (see Figure 8).

[0035] According to the connection structure 10 for a vehicle body structural member of this embodiment, either the first fitting portion 35 or the second fitting portion 25 has a cylindrical or semi-cylindrical tubular portion 37 having an axis along the second direction D2, and the other of the first fitting portion 35 and the second fitting portion 25 has a cylindrical or semi-cylindrical inner circumferential surface 27 that contacts the outer circumferential surface of the tubular portion 37. This results in a configuration in which the first member 30 and the second member 20 can easily rotate relative to each other about the cylindrical first fitting portion 35 and second fitting portion 25, making it possible to control the direction of deformation of the connection portion during a side collision.

[0036] Furthermore, the joining structure 10 for vehicle body structural members according to this embodiment has a first retaining structure and a second retaining structure that prevent the first member 30 and the second member 20 from coming apart in the first direction D1 and the second direction D2, respectively. This prevents the first member 30 and the second member 20 from coming apart when they are joined together, and enables them to be firmly joined together.

[0037] Furthermore, the connection structure 10 for a vehicle body structural member according to this embodiment may have at least one of a friction force increasing portion, an adhesive layer, and a gap for reducing the vibration response of a low-order vibration mode of the vehicle body frame at the mating portion between the first mating portion 35 and the second mating portion 25. This makes it possible to control the vibration mode of the vehicle body frame and the bending mode when a collision load is input during a side collision so as to obtain desired characteristics.

[0038] The joining structure 10 of a vehicle body structural member according to this embodiment is constructed by fitting together a solid first fitting portion 35 and a solid second fitting portion 25 which are formed by processing a first member 30 and a second member 20, each of which has a core material 23, 33 made of a porous material covered with a surface layer material 21, 31 made of fiber reinforced resin. Therefore, by preparing members of any size in which a core material made of a porous material is covered with a surface layer material made of fiber reinforced resin, it is possible to construct frame structures with a variety of combinations.

[0039] A vehicle body structure is formed by joining structural members such as roof rails, rear pillars, front pillars, center pillars, and side sills, each of which has a pillar shape. The vehicle body structure is formed by joining each structural member to each other using a joining structure 10 for vehicle body structural members according to this embodiment. Conventionally, in the case of a monocoque structure, dedicated products designed for each vehicle model, such as the length and thickness of each structural member, have been used, making it difficult to share structural members between different vehicle models, resulting in low versatility of the structural members.

[0040] In contrast, with a vehicle body structure that employs the connection structure 10 for vehicle body structural members according to this embodiment, a variety of vehicle body structures can be constructed by preparing multiple structural members of any length and thickness, cutting the structural members to any length depending on the size of the vehicle body to be manufactured, and forming solid first fitting portions 35 and second fitting portions 25 in appropriate positions. Therefore, the structural members can be freely processed and joined to each other, thereby increasing the versatility of the structural members. Furthermore, with the connection structure 10 for vehicle body structural members according to this embodiment, a firmly joined vehicle body structure can be obtained without using welding or fastening members such as metal bolts.

[0041] <2. Joining method of body structural members> Next, a method for joining members using the joining structure for vehicle body structural members according to this embodiment will be described.

[0042] 9 to 11 are explanatory diagrams showing a method for joining the first member 30 and the second member 20. FIG. 9 shows an example of a method for manufacturing the second member 20. For example, a surface layer material 21 made of carbon fiber reinforced resin is formed so as to cover the periphery of an aluminum porous material (a honeycomb structure in the illustrated example). At this time, the surface layer material 21 is not provided in the region of the core material 23 where the solid second fitting portion 25 is to be formed, and an exposed portion 43 is formed in which the core material 23 is exposed. Note that the method for forming the surface layer material 21 is not particularly limited.

[0043] 10, a filler is then filled into the pores of the porous material of the core material 23 via the exposed portion 43 to form a solid portion. In the example shown, after filler 45 is poured into the pores of the porous material of the core material 23, uncured resin 49 is supplied by an injection device 47 to fill the pores, and the filler 45 and uncured resin 49 are cured to form the solid portion. Furthermore, the solid portion is machined to form the second fitting portion 25.

[0044] Although not shown in the drawings, the first member 30 is fabricated in the same manner as the second member 20.

[0045] Next, as shown in FIG. 11 , the first fitting portion 35 of the first member 30 and the second fitting portion 25 of the second member 20 are fitted together to join the first member 30 and the second member 20. An adhesive may be applied to part or all of the gap between the first fitting portion 35 and the second fitting portion 25 to bond them together. Furthermore, part of the opposing surface of the first fitting portion 35 and the second fitting portion 25 may be roughened to increase friction. Then, a coating layer 41 made of carbon fiber reinforced resin is disposed so as to cover the joined portion where the first fitting portion 35 of the first member 30 and the second fitting portion 25 of the second member 20 are fitted together, and then cured. This completes the joined structure 10 for a vehicle body structural member according to this embodiment.

[0046] In this way, the method for joining vehicle body structural members according to this embodiment makes it possible to firmly join structural members made of lightweight fiber-reinforced resin composites with a predetermined rigidity without using fasteners such as metal, and to impart anisotropic strength to the joints, thereby controlling the folding mode of the vehicle body side portions in response to loads input from the side of the vehicle body.

[0047] Although preferred embodiments of the technology of the present disclosure have been described in detail above with reference to the accompanying drawings, the technology of the present disclosure is not limited to these examples. It is clear that a person skilled in the art of the technology to which the present disclosure pertains can conceive of various modified or altered examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure. Furthermore, combinations of the above-described embodiments and each modified example also naturally fall within the technical scope of the present disclosure.

[0048] For example, in the first embodiment, an example was described in which the fitting portion that connects the first member and the second member has a timber frame structure, but the fitting portion is not limited to a timber frame structure. As long as the fitting portions formed on the first member and the second member have shapes that can fit or engage with each other and are configured to fit together, the same effects as those described above can be obtained.

[0049] In addition, in each of the above embodiments, the first member and the second member are configured as members having a core material, a surface layer material, and a fitting portion, but the first member and the second member do not have to be fiber-reinforced resin composites as long as they have at least a solid fitting portion. Even in this case, the same effects as those of the above embodiments can be obtained. [Explanation of symbols]

[0050] 10: Bonded structure 20: Second member 25: Second fitting part 27: Inner surface 28:Cylinder part 29: Engagement groove 30: First member 35: First fitting part 36: Protruding part 37:Cylinder part 38: Inner surface 39: Neck 41: Covering layer 51:Opposing part 53:Opposing part 55: Gap 57: Gap 59: Adhesive D1: First direction D2: Second direction

Claims

1. A joining structure for vehicle body structural members, which joins a first member extending along a first direction and a second member extending along a second direction intersecting the first direction, at least one of the first member and the second member being made of a fiber-reinforced resin composite material, the first member has a solid first fitting portion having a predetermined rigidity, the second member has a solid second fitting portion having a predetermined rigidity, the first fitting portion and the second fitting portion are fitted together to connect the first member and the second member, one of the first fitting portion and the second fitting portion has a cylindrical or semi-cylindrical tubular portion having an axis along the second direction, A joining structure for a vehicle body structural member, wherein the other of the first fitting portion and the second fitting portion has a cylindrical or semi-cylindrical inner peripheral surface that contacts the outer peripheral surface of the tubular portion.

2. 2. The joining structure of vehicle body structural members according to claim 1, further comprising a first retaining structure that prevents the first member and the second member from separating in the first direction.

3. 3. The joining structure of vehicle body structural members according to claim 2, further comprising a second retaining structure that prevents the first member and the second member from separating in a direction intersecting the first direction.

4. 2. The joining structure of a vehicle body structural member according to claim 1, wherein the mating portion between the first mating portion and the second mating portion has at least one of a friction force increasing portion, an adhesive layer, and a gap for reducing vibration response of a low-order vibration mode of the vehicle body frame.

5. 2. The connection structure of vehicle body structural members according to claim 1, wherein the second direction is a longitudinal direction of the vehicle body, and the second member is a side sill or a roof rail.

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