Vehicle body side structure

Abstract

A vehicle body side structure including a side sill that is formed from a fiber-reinforced resin composite material and extends along the vehicle body longitudinal direction, and a center pillar that is connected to an intermediate portion of the side sill in the vehicle body longitudinal direction, wherein structural members are respectively connected to both end sides of the side sill in the vehicle body longitudinal direction via metal coupling members, and each coupling member has a rotation restricting portion that allows twisting of the end portion of the side sill in the shaft rotation direction relative to the structural member but restricts a prescribed amount or more of said twisting.

Description

Body side structure

[0001] The technology of the present disclosure relates to a vehicle body side structure including a side sill made of a fiber-reinforced resin composite material.

[0002] In recent years, with the aim of reducing the weight of vehicle bodies such as passenger cars, the use of fiber-reinforced resins, such as carbon fiber reinforced plastics (hereinafter referred to as "CFRP"), to manufacture vehicle body structures has been considered. Fiber-reinforced resin members have high rigidity and exhibit high strength, particularly against compressive stress or tensile stress acting along the fiber orientation direction. For example, Patent Documents 1 and 2 disclose hollow fiber-reinforced composite frames that can be used for center pillars, side sills, and the like of vehicle body structures.

[0003] Japanese Patent Application Laid-Open No. 2020-062916

[0004] However, when fiber-reinforced resin side sills are used, the torsion angle of the side sills becomes small because fiber-reinforced resin has lower ductility than steel. Therefore, when a collision load is applied to the center pillar and side sill during a side collision, stress concentrates at the connection between the center pillar and side sill, which may cause the connection to break. Furthermore, if the side sill itself is made more twistable to prevent the connection from breaking, the center pillar and side sill may collapse excessively toward the passenger compartment as a unit.

[0005] 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 a vehicle body side structure that reduces the risk of the connection between the center pillar and the side sill breaking due to the collision load during a side collision when the side sill to which the lower part of the center pillar is connected is made of fiber-reinforced resin, and that can prevent the center pillar from collapsing excessively toward the passenger compartment.

[0006] In order to solve the above problems, according to one aspect of the technology of the present disclosure, there is provided a vehicle side structure including a side sill made of a fiber-reinforced resin composite extending along the longitudinal direction of the vehicle body, and a center pillar connected to a midpoint of the side sill in the longitudinal direction of the vehicle body, wherein structural members are connected to both ends of the side sill in the longitudinal direction of the vehicle body via metal connecting members, and the connecting members have a rotation restricting portion that allows twisting of the end of the side sill relative to the structural member in the axial rotation direction and restricts the twisting to a predetermined amount or more.

[0007] As described above, the technology of the present disclosure aims to reduce the risk of the connection between the center pillar and the side sill breaking due to the collision load during a side collision, and to prevent the center pillar from collapsing excessively toward the passenger compartment, when the side sill to which the lower part of the center pillar is connected is made of fiber-reinforced resin.

[0008] Fig. 1 is a schematic diagram showing the overall configuration of the vehicle body side structure according to the present embodiment. Fig. 2 is an explanatory diagram showing the vehicle body side structure of a reference example. Fig. 3 is an explanatory diagram showing the vehicle body side structure of a reference example. Fig. 4 is a perspective view showing a connection portion between a side sill and a front pillar of the vehicle body side structure according to the present embodiment. Fig. 5 is a side view showing a connection portion between a side sill and a front pillar of the vehicle body side structure according to the present embodiment. Fig. 6 is an explanatory diagram showing the operation of the vehicle body side structure according to the present embodiment.

[0009] 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.

[0010] First, an outline of the vehicle body side structure according to this embodiment will be described. Fig. 1 is a schematic diagram showing the appearance of a vehicle body side structure 1. The vehicle body side structure 1 shown in Fig. 1 schematically shows a part of the structure of the left side of a vehicle. As shown in Fig. 1, in this specification, the fore-and-aft direction of the vehicle body is represented as the X direction, the vehicle width direction as the Y direction, and the vehicle height direction as the Z direction.

[0011] The vehicle body side structure 1 is configured to include a front pillar 2, a center pillar 3, a rear pillar 4, a roof rail 5, and a side sill 6. The roof rail 5 extends in the fore-and-aft direction of the vehicle body above the vehicle interior space and forms the side portion of the vehicle roof. The side sill 6 extends in the fore-and-aft direction of the vehicle body below the side of the vehicle.

[0012] The front pillar 2 has a lower end connected to the front end of the side sill 6 and an upper end connected to the front end of the roof rail 5. The front pillar 2 forms the front portion of the vehicle's cabin space and is positioned to support the side of the windshield. The rear pillar 4 has a lower end connected to the rear end of the side sill 6 and an upper end connected to the rear end of the roof rail 5. The center pillar 3 has a lower end connected to the middle portion of the side sill 6 in the fore-and-aft direction of the vehicle body and an upper end connected to the center portion of the roof rail 5 in the fore-and-aft direction of the vehicle body. The front pillar 2 and the rear pillar 4 are structural members connected to both ends of the side sill 6 in the fore-and-aft direction of the vehicle body.

[0013] An opening for a front door is formed between the side sill 6, the roof rail 5, the front pillar 2, and the center pillar 3. In addition, an opening for a rear door is formed between the side sill 6, the roof rail 5, the rear pillar 4, and the center pillar 3. Each of the components constituting the vehicle body side structure 1 may be formed by combining a plurality of components.

[0014] In this embodiment, at least the side sill 6 is made of a fiber-reinforced resin composite material. The side sill 6, roof rail 5, front pillar 2, and center pillar 3 may all be made of a fiber-reinforced resin composite material. A fiber-reinforced resin composite material is a structural material molded using a fiber-reinforced resin in which reinforcing fibers such as carbon fibers are impregnated with a thermoplastic resin or a thermosetting resin as a matrix resin. The fiber-reinforced resin composite material may also include a reinforcing plate made of any metal.

[0015] When the matrix resin is a thermoplastic resin, its main material may be, for example, any one or a mixture of two or more of 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. Alternatively, the thermoplastic resin may be a copolymer of the above resins. When a mixture of these thermoplastic resins is used as the matrix resin, a compatibilizer may be further added. 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.

[0016] When the matrix resin is a thermosetting resin, its main material may be, for example, one or a mixture of two or more of epoxy resin, unsaturated polyester resin, vinyl ester resin, phenolic resin, polyurethane resin, and silicone resin. The thermosetting resin may also contain an appropriate curing agent or reaction accelerator.

[0017] The carbon fibers may contain an appropriate ratio of continuous fibers oriented in the Z direction (axial fibers) and continuous fibers oriented in a direction intersecting the Z direction (cross fibers). The amount of axial fibers can adjust the tensile stress generated by the load input during a side collision. The amount of cross fibers can adjust the rigidity against the input load during a side collision, thereby adjusting the amount of energy absorption. Furthermore, the carbon fibers may contain short fibers in addition to the continuous fibers, and may contain fibers other than carbon fibers as reinforcing fibers.

[0018] The problem to be solved by the present disclosure will now be described in detail. Figures 2 and 3 each show a configuration of a reference example in which the problem to be solved by the present disclosure may occur.

[0019] As shown in Figure 2, in a vehicle body side structure, if at least the side sill 6 is made of CFRP and its ends are connected to the front pillar 2 and rear pillar 4, the torsion angle of the side sill 6 relative to the front pillar 2 and rear pillar 4 will be small. In this case, if a collision load F input during a side collision is applied to the center pillar 3 and side sill 6, the center pillar 3 will tilt toward the inside of the vehicle body, and there is a risk that the connection portion 9 between the center pillar 3 and the side sill 6 will break. This is because the ductility of CFRP is smaller than that of steel, close to zero, and therefore stress is concentrated at the connection portion 9.

[0020] In contrast, as shown in Figure 3, if the front pillar 2 and the side sill 6, and the rear pillar 4 and the side sill 6 are connected using metal connecting members 50, respectively, the torsional angle of the side sill 6 relative to the front pillar 2 and the rear pillar 4 increases due to the ductility of the metal. However, in this case, the center pillar 3 is likely to collapse toward the passenger compartment together with the side sill 6. In particular, in an electric vehicle powered by a drive motor and equipped with a battery under the floor that supplies power to the drive motor, there is a risk that the battery may be damaged by the center pillar 3 collapsing toward the passenger compartment.

[0021] In the vehicle body side structure 1 according to this embodiment, a front pillar 2 and a rear pillar 4 are connected to both ends of the side sill 6 in the vehicle longitudinal direction via metal connecting members. The connecting members have rotation restricting portions that allow twisting of the end of the side sill 6 relative to the front pillar 2 or the rear pillar 4 in the axial rotation direction and restrict twisting to a predetermined amount or more. As a result, the vehicle body side structure 1 according to this embodiment has a configuration that can suppress breakage of the connection portion 9 between the center pillar 3 and the side sill 6 and suppress excessive collapse of the center pillar 3 toward the vehicle interior. Below, the structure of the connection portion between the side sill 6 and structural members (the front pillar 2 and the rear pillar 4) will be described using the connection portion between the side sill 6 and the front pillar 2 as an example.

[0022] 4 and 5 are diagrams shown to explain the configuration of the connection portion between the side sill 6 and the front pillar 2 of the vehicle body side structure 1 according to this embodiment. Fig. 4 is a perspective view showing the configuration of the connection portion between the side sill 6 and the front pillar 2. Fig. 5 is a side view showing the connection portion between the side sill 6 and the front pillar 2.

[0023] The front pillar 2 is connected to the front end of the side sill 6 via a metal connecting member 20. The connecting member 20 has a rotation restricting portion 21 that allows twisting of the end of the side sill 6 relative to the front pillar 2 in the axial rotation direction and restricts twisting beyond a predetermined amount.

[0024] The illustrated connecting member 20 is a solid columnar member having a substantially rectangular cross section. The connecting member 20 is made of a highly ductile metal material, such as aluminum or steel. The connecting member 20 has connecting portions 27, 29 at both ends. The connecting portion 27, located on the rear side of the vehicle body, is inserted into the end of the hollow side sill 6 on the front side of the vehicle body and joined thereto with an adhesive or the like. The connecting portion 29, located on the front side of the vehicle body, is inserted into the end of the hollow front pillar 2 on the rear side of the vehicle body and joined thereto with an adhesive or the like.

[0025] The method of joining the joints 27, 29 to the side sill 6 or the front pillar 2 is not limited to a joining method using an adhesive, and may be joining using bolts, etc. However, if the joining method uses an adhesive, it is possible to join the joints 27, 29 to the side sill 6 or the front pillar 2 without cutting the continuous fibers that make up the side sill 6 or the front pillar 2.

[0026] The connecting member 20 has a rotation restricting portion 21 on a side surface of the outer circumferential surface that is located outward in the vehicle width direction. The rotation restricting portion 21 has a first portion 23 and a second portion 25 that are spaced apart and that face each other in the axial rotation direction in at least a partial area. The first portion 23 and the second portion 25 are each erect portions that extend outward from the outer circumferential surface of the connecting member 20. The first portion 23 and the second portion 25 may be formed on the outer surface of the connecting member 20 by, for example, grinding, or may be joined to the outer surface of the connecting member 20 by welding or the like.

[0027] The first portion 23 and the second portion 25 are spaced apart in the axial rotation direction, thereby allowing the side sill 6 to twist relative to the front pillar 2. On the other hand, when the side sill 6 twists relative to the front pillar 2, the first portion 23 and the second portion 25 come into contact with each other, restricting twisting beyond a predetermined amount.

[0028] In this embodiment, the first portion 23 and the second portion 25 have engaging portions 23a, 25a that engage with each other when the end of the side sill 6 twists relative to the front pillar 2 in the axial rotation direction (see FIG. 5 ). Specifically, the first portion 23 and the second portion 25 each have a base portion 23b, 25b that extends in the direction in which the side sill 6 twists relative to the front pillar 2, relative to the axis of the columnar connecting member 20, and the engaging portions 23a, 25a that are inclined in the direction opposite to the direction in which the side sill 6 twists relative to the front pillar 2. Therefore, when the side sill 6 twists relative to the front pillar 2, the engaging portions 23a, 25a of the first portion 23 and the second portion 25 engage with each other, thereby increasing resistance to the twisting.

[0029] The amount of twisting until the first portion 23 and the second portion 25 come into contact with each other when the side sill 6 twists relative to the front pillar 2 varies depending on the distance between the erected first portion 23 and second portion 25. Therefore, when the side sill 6 twists relative to the front pillar 2, the allowable range of twisting can be freely designed.

[0030] Furthermore, the strength of each of the first portion 23 and the second portion 25 varies depending on the thickness of the erected first portion 23 and the second portion 25. Therefore, when the side sill 6 twists relative to the front pillar 2 and the first portion 23 and the second portion 25 come into contact with each other, the allowable range of the twist can be freely designed.

[0031] Figure 6 is an explanatory diagram showing the state when the side sill 6 twists relative to the front pillar 2. The left side of Figure 6 shows a view of the connection between the front pillar 2 and the side sill 6 from the side, and the right side of Figure 6 shows a schematic view of the connection between the front pillar 2 and the side sill 6 as seen in the axial direction.

[0032] When the side sill 6 is not twisting relative to the front pillar 2, the first portion 23 and the second portion 25 are spaced apart. When the center pillar 3 receives a collision load during a side collision of the vehicle, the center pillar 3 collapses toward the passenger compartment, causing the side sill 6 to begin to twist relative to the front pillar 2. At this time, because the ductility of the connecting member 20 is higher than the ductility of the center pillar 3, which is made of a fiber-reinforced plastic composite material, it is possible to generate a twist at the connection portion between the front pillar 2 and the side sill 6. However, in the initial stage of the twisting, the first portion 23 and the second portion 25 are maintained spaced apart, and therefore the first portion 23 and the second portion 25 do not exert any resistance to the twisting.

[0033] When the twisting of the side sill 6 relative to the front pillar 2 progresses further and reaches a predetermined amount, the engaging portions 23a, 25a of the first portion 23 and the second portion 25 come into contact with each other. As a result, the strength of the first portion 23 and the second portion 25 acts as a resistance force against the twisting, restricting the twisting. In particular, in this embodiment, the engaging portions 23a, 25a of the first portion 23 and the second portion 25 are engaged with each other, thereby increasing the resistance force against the twisting. This makes it easier to adjust the allowable range of twisting of the side sill 6 relative to the front pillar 2.

[0034] In the above embodiment, the rotation restricting portion 21 composed of the first portion 23 and the second portion 25 is provided on the outer side surface in the vehicle width direction of the connecting member 20 having a rectangular cross section, but the first portion 23 and the second portion 25 may also be provided on one or more of the inner side surface, top surface, and bottom surface in the vehicle width direction of the connecting member 20. The resistance force against torsion of the side sill 6 relative to the front pillar 2 can also be designed by changing the number of pairs of the first portion 23 and the second portion 25.

[0035] The connection portion of the side sill 6 to the rear pillar 4 is configured similarly to the connection portion of the side sill 6 to the front pillar 2, and both ends of the side sill 6 are connected to the front pillar 2 and the rear pillar 4 via connecting members 20 having rotation restricting portions 21. Therefore, while torsion of the side sill 6 relative to each of the front pillar 2 and the rear pillar 4 is permitted, torsion of more than a predetermined amount is restricted. This makes it possible to prevent the center pillar 3 from excessively collapsing toward the passenger compartment. In particular, in a vehicle with a battery mounted under the passenger compartment floor, this makes it possible to prevent damage to the battery due to the center pillar 3 collapsing toward the passenger compartment.

[0036] 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.

[0037] For example, in the above embodiment, an example was described in which the rotation regulating portion 21 is configured by a first portion 23 and a second portion 25 each having base portions 23b, 25b that extend in the direction in which the side sill 6 twists relative to the front pillar 2, relative to the axis of the columnar connecting member 20, and engagement portions 23a, 25a that are inclined in the direction opposite to the direction in which the side sill 6 twists relative to the front pillar 2, but the specific configuration of the rotation regulating portion 21 is not limited to the above example.

[0038] Furthermore, the technology of the present disclosure can also be realized as a metal connecting member 20 for connecting structural members (front pillar 2 and rear pillar 4) to both ends of a side sill 6, which allows twisting of the end of the side sill 6 in the axial rotation direction relative to the structural members, while having a rotation restriction portion 21 that restricts twisting beyond a predetermined amount.

[0039] REFERENCE SIGNS LIST 1: Vehicle body side structure 2: Front pillar 3: Center pillar 4: Rear pillar 5: Roof rail 6: Side sill 20: Connecting member 21: Rotation restricting portion 23: First portion 23a: Engaging portion 23b: Base portion 25: First portion 25a: Engaging portion 25b: Base portion

Claims

1. A side sill made of fiber-reinforced resin composite material extending along the front-to-rear direction of the vehicle body, The center pillar connected to the intermediate part of the side sill in the longitudinal direction of the vehicle body, In a vehicle body side structure equipped with, Structural members are connected to both ends of the side sill in the front-rear direction of the vehicle body via metal connecting members. The connecting member has a rotation restricting portion that allows twisting of the end of the side sill relative to the structural member in the axial rotation direction, and restricts the twisting beyond a predetermined amount. The rotation restricting portion has a first portion and a second portion, at least a portion of which are arranged opposite and spaced apart from each other in the direction of axial rotation, and when twisting occurs in the direction of axial rotation at the end of the side sill relative to the structural member, the first portion and the second portion come into contact to restrict the twisting beyond a predetermined amount, a vehicle body side structure.

2. The first and second portions are, respectively, erected portions extending outward from the outer circumferential surface of the connecting member. The vehicle body side structure according to claim 1.

3. The connecting member is a columnar member with a rectangular cross-section, The pair of the first and second portions are provided on one of the surfaces of the columnar member. The vehicle body side structure according to claim 2.

4. The connecting member is a columnar member with a rectangular cross-section, The pair of the first and second portions are provided on multiple surfaces of the columnar member, The vehicle body side structure according to claim 2.

5. The first and second portions have engaging portions that engage with each other when torsion occurs in the axial rotational direction of the end of the side sill relative to the structural member. The vehicle body side structure according to claim 1.

6. A connecting member for connecting structural members to both ends of a side sill to which a center pillar is connected in the middle of the vehicle body in the longitudinal direction, The connecting member is a metal member and allows torsion in the axial rotation direction of the end of the side sill relative to the structural member, while having a rotation restricting portion that restricts the torsion beyond a predetermined amount. The rotation restricting portion has a first portion and a second portion, at least a portion of which are arranged opposite and spaced apart from each other in the axial rotation direction, and when twisting occurs in the axial rotation direction at the end of the side sill relative to the structural member, the first portion and the second portion come into contact to restrict the twisting beyond a predetermined amount. Connecting member.