Vehicle body front part structure

Abstract

This vehicle body front part structure comprises a bumper beam, a front-side frame that is composed of a fiber-reinforced resin composite material, a crash box that is disposed between the bumper beam and the front-side frame and that is composed of a fiber-reinforced resin composite material, and a support member that is disposed between the crash box and the front-side frame and that supports the crash box. A reinforcing member, which is provided contacting the support member or provided extending from the support member, is mechanically fastened to a support-member-side end part of the front-side frame.

Description

Front body structure

[0001] The present disclosure relates to a front body structure.

[0002] Vehicles are equipped with energy absorption members that crush during a collision to absorb the collision load. Conventionally, energy absorption members were made of metal materials such as steel, but in recent years, due to the weight reduction of the vehicle body, the development of energy absorption members made of fiber reinforced resin composites containing reinforcing fibers typified by carbon fiber has been underway. A typical example of an energy absorption member is a cylindrical crush box disposed between the front bumper beam at the front of the vehicle body and the vehicle body frame. In addition, for the purpose of weight reduction of the vehicle body, it has been considered to configure not only the crush box but also the front side frame using a fiber reinforced resin composite.

[0003] Japanese Patent Application Laid-Open No. 2017-001599

[0004] Here, when the crush box and the front side frame at the front of the vehicle body are replaced with a fiber reinforced resin composite, it is not possible to expect energy absorption utilizing the bending deformation of the engine block on which an engine or the like is mounted. In addition, due to the characteristics of the fiber reinforced resin composite, it is required to efficiently absorb the collision load by sequentially crushing (sequentially collapsing) in the axial direction starting from the tip side of the energy absorption member.

[0005] In order to sequentially crush an energy absorption member made of a fiber reinforced resin composite, the shape of the tip portion that is the starting point of the crush is important. Generally, the plate thickness of the tip portion of the energy absorption member is tapered, and by starting destruction from the tip portion of the energy absorption member and sequentially crushing it in the axial direction, it is possible to ensure a relatively large energy absorption amount during a frontal collision. On the other hand, during a minor collision, from the viewpoint of suppressing the labor and cost of replacing vehicle body parts, it is desirable to cause only the crush box to crush without crushing the front side frame. However, when the tip portion of the front side frame is tapered and both the crush box and the front side frame are sequentially crushed from the tip side during a frontal collision of the vehicle, the tip portion of the front side frame may be damaged even during a minor collision.

[0006] Therefore, this disclosure has been made in view of the above-mentioned problems, and the purpose of this disclosure is to provide a front body structure that suppresses damage to the front side frame during minor collisions, while enabling efficient energy absorption by sequentially crushing the crash box and front side frame during forward collisions.

[0007] To solve the above problems, according to one aspect of the technology of this disclosure, is provided.

[0008] As explained above, the technology of this disclosure suppresses damage to the front side frame during minor collisions, while simultaneously enabling efficient energy absorption by sequentially crushing the crash box and front side frame during forward collisions.

[0009] This is a schematic diagram showing the basic configuration of the front body structure according to this embodiment. This is a cross-sectional view showing the basic configuration of the front body structure according to the same embodiment. This is a schematic diagram showing a part of the front body structure according to the same embodiment viewed from the left. This is a schematic diagram showing a part of the front body structure according to the same embodiment viewed from the right. This is a cross-sectional view showing the configuration of the front body structure according to a modified example of the same embodiment. This is a schematic diagram showing a part of the front body structure according to a modified example of the same embodiment viewed from the left. This is a schematic diagram showing a part of the front body structure according to a modified example of the same embodiment viewed from the right. This is an explanatory diagram showing the behavior of the load when the front body structure according to the same embodiment is crushed by an axle. This is an explanatory diagram showing how the front body structure according to the same embodiment is crushed by an axle. This is an explanatory diagram showing how the front body structure according to the same embodiment is crushed by an axle. This is an explanatory diagram showing how the front body structure according to the same embodiment is crushed by an axle. This is an explanatory diagram showing how the front body structure according to the same embodiment is crushed by an axle. This is an explanatory diagram showing how the front body structure according to the same embodiment is crushed by an axle.

[0010] Preferred embodiments of the technology of this disclosure will be described in detail below with reference to the attached drawings. In this specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant descriptions will be omitted.

[0011] <Configuration of the Front Body Structure> Figures 1 to 4 are explanatory diagrams showing the front body structure 1 according to this embodiment. Figure 1 is a schematic diagram of the right front portion of the vehicle body frame as seen from above the vehicle body. Figure 2 is a partial cross-sectional view of the front body structure 1 shown in Figure 1. Figure 3 is a schematic diagram of a part of the front body structure 1 shown in Figure 1 as seen from the left side, and Figure 4 is a schematic diagram of a part of the front body structure 1 shown in Figure 1 as seen from the right side. In the following description, the front-rear direction of the vehicle body is also called the X direction, the vehicle width direction is also called the Y direction, and the vehicle height direction is also called the Z direction. In addition, the front side of the vehicle body may be called the front end side, and the rear side of the vehicle body may be called the rear end side.

[0012] The front body structure 1 comprises a bumper beam 3, a crash box joining member 10, a crash box 20, a side frame joining member 30, a front side frame 40, and reinforcing members 61 and 65. The crash box joining member 10 is joined to the bumper beam 3. The front end 21 of the crash box 20 is joined to the crash box joining member 10, and the rear end 23 of the crash box 20 is joined to the side frame joining member 30. The side frame joining member 30 is joined to the rear end of the crash box 20. The front end 41 of the front side frame 40 is joined to the side frame joining member 30. The rear end 43 of the front side frame 40 is joined to an appropriate vehicle frame 5 such as a side member.

[0013] (Bumper Beam) The bumper beam 3 is made of a metal such as steel, and is installed inside the front bumper of the vehicle. It has the function of mitigating the impact during a collision and reducing the damage to the vehicle body.

[0014] (Crush Box Joining Member) The crash box joining member 10 is positioned opposite the front end 21 of the crash box 20, where the impact load is expected to be applied, and is fixed to the bumper beam 3 to support the front end 21 of the crash box 20. The crash box joining member 10 is a molded product made of a metal material such as steel or aluminum, and has higher rigidity than a fiber-reinforced resin molded body. The crash box joining member 10 is fixed to the bumper beam 3 by fastening members such as bolts (not shown) or by welding. However, the joining method is not particularly limited.

[0015] The crash box joining member 10 has a base portion 11 and a cylindrical portion 13. The base portion 11 is a plate-shaped part that serves as the base of the crash box joining member 10 and is fixed to the bumper beam 3. The cylindrical portion 13 extends from the base portion 11 toward the crash box 20. The cylindrical portion 13 surrounds the front end portion 21 of the crash box 20 and has an inner surface that is joined to the outer surface of the end portion 21 by adhesive. In other words, the crash box joining member 10 is joined to the front end portion 21 of the crash box 20 by adhesive.

[0016] (Crash Box) The crash box 20 is a cylindrical member positioned along the longitudinal direction of the vehicle body in its axial direction. The crash box 20 is made of a fiber-reinforced resin composite material and functions as an energy absorbing member that absorbs collision energy by receiving the collision load via the bumper beam 3 and collapsing axially when the front of the vehicle collides with a preceding vehicle, obstacle, or other obstacle. The crash box 20 also has the function of transmitting the collision load to the side frame joining member 30 and the front side frame 40.

[0017] The leading end 21 of the crash box 20 is supported by the crash box joining member 10, and the rear end 23 of the crash box 20 is supported by the side frame joining member 30. In this embodiment, the crash box 20 is a cylindrical member whose outer shape is rectangular in cross-section perpendicular to the axial direction. Hereinafter, when referring to "cross-section," it means a cross-section perpendicular to the axial direction.

[0018] The overall dimensions of the crash box 20 may be designed appropriately according to the size of the vehicle, the required energy absorption, the weight of the crash box 20, etc. For example, the axial length of the crash box 20 may be 100 to 200 mm, and the dimensions of two sides of the cross-section may be 50 to 100 mm each. Also, the thickness of the wall portion of the crash box 20 may be, for example, 5 to 10 mm. However, the dimensions of the crash box 20 are not limited to the above example.

[0019] The crash box 20 is a fiber-reinforced resin composite material containing at least carbon fibers and a matrix resin, enabling high strength and lightweight construction. The crash box 20 made of fiber-reinforced resin composite material generates load by axially crushing while continuously fracturing when an impact load is applied, achieving stable energy absorption characteristics with little load fluctuation. Furthermore, the crash box 20 made of fiber-reinforced resin composite material has the characteristics of minimal residual deformation and high energy absorption per unit weight.

[0020] The crush box 20 is manufactured, for example, by weaving multiple continuous fibers together and integrating them with a matrix resin to cure. The reinforcing fibers used in the crush box 20 may include not only carbon fibers but also organic fibers such as glass fibers, ceramic fibers, and aramid fibers.

[0021] The matrix resin used in the crush box 20 may be a thermosetting resin or a thermoplastic resin. If the matrix resin is a thermosetting resin, its main component may be one or more of the following: epoxy resin, unsaturated polyester resin, vinyl ester resin, phenolic resin, polyurethane resin, and silicone resin. When these thermosetting resins are used as the matrix resin, appropriate curing agents and reaction accelerators may be added.

[0022] When the matrix resin is a thermoplastic resin, the main material may be one or more of the following: 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 added. Furthermore, the thermoplastic resin may be given a flame retardant such as a brominated flame retardant, a silicon-based flame retardant, or red phosphorus.

[0023] The crash box 20 includes, for example, axial fibers oriented along the axial direction and cross fibers (also called helical fibers) wound along a direction intersecting the axial direction. The cross fibers are wound along directions inclined to the left and right with respect to the axial direction. The axial fibers have the function of exhibiting rigidity against loads applied in the axial direction. The cross fibers also have the function of exhibiting rigidity against loads applied from a direction oblique to the axial direction. By adjusting the number and density of these axial fibers and cross fibers, the energy absorption characteristics of the crash box 20 can be arbitrarily designed.

[0024] The inner circumferential surface of the front end 21 of the crash box 20, where the impact load is expected to be applied, has a tapered shape that widens towards the end face. As a result, the thickness of the wall portion of the crash box 20 gradually decreases towards the end face. On the other hand, the thickness of the wall portion of the rear end 23 of the crash box 20 remains constant. This results in the strength of the front end 21 of the crash box 20 being relatively low. Therefore, when an axial load is applied to the crash box 20, fracture is induced from the front end of the crash box 20.

[0025] (Side frame joining member) The side frame joining member 30 is joined opposite to the front end 41 of the front side frame 40 to support the front end 41 of the front side frame 40. The side frame joining member 30 is also joined opposite to the rear end 23 of the crash box 20 to support the rear end 23 of the crash box 20. In other words, the side frame joining member 30 is provided between the rear end 23 of the crash box 20 and the front end 41 of the front side frame 40.

[0026] The side frame joining member 30 is a molded product made of a metal material such as steel or aluminum, and has higher rigidity than a fiber-reinforced resin molded body. The side frame joining member 30 has a base portion 31 and a cylindrical portion 33. The base portion 31 is the base part of the side frame joining member 30 and has a recess that opens towards the front side frame 40. The cylindrical portion 33 is provided extending from the base portion 31 towards the crush box 20.

[0027] The recess in the base portion 31 surrounds the front end portion 41 of the front side frame 40 and has an inner circumferential surface that is bonded to the outer circumferential surface of the end portion 41 with adhesive. The cylindrical portion 33 surrounds the rear end portion 23 of the crash box 20 and has an inner circumferential surface that is bonded to the outer circumferential surface of the end portion 23 with adhesive. In other words, the side frame joining member 30 is bonded between the crash box 20 and the front side frame 40 with adhesive. The cylindrical portion 33 has the function of preventing the crash box 20 from tipping over when the crash box 20 is axially crushed.

[0028] (Front Side Frame) The front side frame 40 is a cylindrical member whose axial direction is aligned with the longitudinal direction of the vehicle body. The front side frame 40 constitutes part of the vehicle body frame and is a member that supports the drive system, such as the engine, drive motor, and transmission, which are mounted at the front of the vehicle. In this embodiment, the front side frame 40 is made of a fiber-reinforced resin composite material and functions as an energy absorbing member that absorbs collision energy by axially colliding with the collision load when the front of the vehicle collides with a preceding vehicle, obstacle, or other obstacle.

[0029] The front end 41 of the front side frame 40 is supported by the side frame joining member 30, and the rear end 43 of the front side frame 40 is supported by the support plate 50. The side frame joining member 30 is connected to the rear end 23 of the crash box 20. The support plate 50 is fixed to the front end of the vehicle body frame 5. In this embodiment, the front side frame 40 is a cylindrical member with a rectangular outer shape in cross-section perpendicular to the axial direction.

[0030] The overall dimensions of the front side frame 40 may be designed appropriately according to the size of the vehicle, the required energy absorption and rigidity, the weight of the front side frame 40, etc. For example, the axial length of the front side frame 40 may be 500 to 1,000 mm, and the dimensions of the two sides of the cross-section may be 100 to 200 mm each. Also, the thickness of the wall portion of the front side frame 40 may be, for example, 5 to 15 mm. However, the dimensions of the front side frame 40 are not limited to the above example.

[0031] The fiber-reinforced resin composite material constituting the front side frame 40 may be the same as the fiber-reinforced resin composite material constituting the crush box 20. Also, like the crush box 20, the thickness of the wall portion of the front end 41 of the front side frame 40 gradually decreases towards the end face. On the other hand, the thickness of the wall portion of the rear end 43 of the front side frame 40 remains constant. As a result, the strength of the front end 41 of the front side frame 40 in the axial direction is relatively small. Therefore, when an axial load is applied to the front side frame 40, fracture is induced from the front end.

[0032] The rear end portion 43 of the front side frame 40 is supported by the cylindrical portion 51 of the support plate 50. The cylindrical portion 51 surrounds the rear end portion 43 of the front side frame 40 and has an inner surface that is bonded to the outer surface of the end portion 43 with adhesive. The cylindrical portion 51 has the function of preventing the front side frame 40 from collapsing when the front side frame 40 is axially crushed.

[0033] (Reinforcement Members) The reinforcement members 61 and 65 are provided at the front end 41 of the front side frame 40, either in contact with the side frame joining member 30 or extending from the side frame joining member 30. The reinforcement members 61 and 65 are mechanically fastened to the front side frame 40. In this disclosure, "mechanical fastening" means a fastening method using fastening members such as bolts, screws, or rivets, and does not include joining by adhesive or welding. The front body structure 1 according to this embodiment has a pair of reinforcement members 61 and 65 that are mechanically fastened to the left and right sides of the front side frame 40, respectively, and are provided in contact with the side frame joining member 30.

[0034] As shown in Figure 3, the reinforcing member 61, which is mechanically fastened to the left side of the front side frame 40, is fastened to the front side frame 40 using fastening members 69 such as bolts, screws, or rivets. The reinforcing member 61 has a hole 63 in its center. A front cross member 9, which extends in the vehicle width direction, is inserted into the hole 63. The front cross member 9 is used as a vehicle frame to support one or more of the drive motor, engine, and transmission, for example.

[0035] As shown in Figure 4, the reinforcing member 65, which is mechanically fastened to the right side of the front side frame 40, is fastened to the front side frame 40 using fastening members 69 such as bolts, screws, or rivets. The reinforcing member 65 has a groove 67 in the center in the height direction. A support member 7, which extends from the bumper beam 3 in a direction inclined with respect to the longitudinal direction of the vehicle body, is inserted into the groove 67. The support member 7 has a predetermined rigidity against loads during a collision from the front right of the vehicle body (offset collision). The support member 7 suppresses the collision load from entering the vehicle body at an angle during an offset collision, and allows the collision load to enter in the longitudinal direction of the vehicle body, enabling energy absorption by the crash box 20 and the front side frame 40.

[0036] The load-bearing capacity of the fastening points of the reinforcing members 61 and 65 by the fastening member 69 is designed to be greater than the load at which the crash box 20 will axially collapse due to the collision load. Therefore, when a collision load is applied during a frontal collision of the vehicle, the axial collapse of the crash box 20 progresses before the fastening points of the reinforcing members 61 and 65 break. Consequently, in the event of a minor collision, the tip of the front side frame 40 is protected by the side frame joining member 30, and damage to the front side frame 40 can be avoided.

[0037] The pair of reinforcing members 61 and 65 described above are each provided in contact with the side frame joining member 30 and mechanically fastened to the left and right sides of the front side frame 40, respectively. However, the reinforcing members may extend from the side frame joining member 30 and be provided integrally. Figures 5 to 7 show a modified example of a pair of reinforcing members 35 and 37 that extend from the side frame joining member 30 and are integrally formed, and mechanically fastened to the left and right sides of the front side frame 40, respectively. The load-bearing capacity of the fastening points of the reinforcing members 35 and 37 by the fastening member 69 is designed to be greater than the load at which the crash box 20 will axially collapse due to the impact load.

[0038] Even with the configuration of the reinforcing members 35 and 37 shown in the modified example, when a collision load is applied during a frontal collision of the vehicle, the axial crushing of the crash box 20 progresses before the fastening points of the reinforcing members 35 and 37 break. Therefore, in the event of a minor collision, the front end of the front side frame 40 is protected by the side frame joining member 30, and damage to the front side frame 40 can be avoided.

[0039] In the above embodiments and modifications, the reinforcing members were configured as a pair of reinforcing members mechanically fastened to the left and right sides, respectively. However, the form of the reinforcing members is not limited to the above examples. For example, the reinforcing member may be a cylindrical reinforcing member that is in contact with or extends from the side frame joining member 30 and is provided around the entire circumference of the front side frame 40. Even with such a cylindrical reinforcing member, by being mechanically fastened to the front side frame 40 by the fastening member, the tip of the front side frame 40 is protected by the side frame joining member 30 in the event of a minor collision, thereby preventing damage to the front side frame 40.

[0040] <Load Characteristics> Up to this point, the configuration of the vehicle body front structure 1 according to this embodiment has been described. Next, the load characteristics of the vehicle body front structure 1 will be described.

[0041] Figure 8 shows the load characteristics of the front body structure 1 shown in Figures 1 to 4. Figures 9 to 13 show the front body structure 1 being crushed sequentially over time. The load characteristics show the behavior of the load when the rear end of the front side frame 40 is fixed to the support base and an axial surface load is applied from the crash box joint member 10 toward the front side frame 40. The horizontal axis shows the stroke amount (axial crushing length) of the front body structure 1. The vertical axis shows the resulting load. In the load characteristics shown in Figure 8, the sum of the loads at each stroke amount up to each stroke amount represents the amount of energy absorbed when the front body structure 1 is axially crushed up to that stroke amount.

[0042] In the front body structure 1 of this embodiment, the load increases during the first stroke period T1 after the start of the stroke, and a relatively small load peak occurs. The first stroke period T1 represents the period until the adhesive joining the crash box 20 and the crash box joining member 10 undergoes shear failure (the state shown in Figure 9). The peak at the end of the first stroke period T1 indicates the timing (stroke amount) at which the adhesive undergoes shear failure.

[0043] In the subsequent second stroke period T2, the load decreases. The second stroke period T2 indicates the period until the end face on the tip side of the crash box 20 abuts against the bottom face of the cylindrical portion 13 of the crash box joining member 10 (the state shown in FIG. 10). The second stroke period T2 is a state in which the crash box joining member 10 and the crash box 20 are relatively moving, and the load decreases. However, even after the shear fracture of the adhesive occurs, the load for the stroke until the end face 27 on the tip side of the crash box 20 abuts against the bottom face of the cylindrical portion 13 of the crash box joining member 10 is manifested.

[0044] In the subsequent third stroke period T3, the load increases and the load peak appears again. The third stroke period T3 indicates the period until the axial crushing of the crash box 20 is started. The peak at the end of the third stroke period T3 indicates the timing (stroke amount) at which the axial crushing of the crash box 20 starts. Since the load-bearing capacity of the fastening portion of the front side frame 40 and the reinforcing members 61, 65 by the fastening member 69 is larger than the load for axially crushing the crash box 20, in the third stroke period T3, the fastening portions of the reinforcing members 61, 65 by the fastening member 69 are held in a fastened state without being broken. Therefore, the end portion on the tip side of the front side frame 40 is protected without being damaged.

[0045] In the subsequent fourth stroke period T4, the load changes at a substantially constant value. The fourth stroke period T4 indicates the period in which the axial crushing of the crash box 20 progresses (the state shown in FIG. 11). In the present embodiment, since the crash box 20 having a uniform cross section in the axial direction is axially crushed, the load that appears changes at a substantially constant value. The end of the fourth stroke period T4 indicates the timing (stroke amount) at which the axial crushing of the crash box 20 ends.

[0046] In the subsequent fifth stroke period T5, the load increases and a peak of the load appears again. The fifth stroke period T5 indicates the period until the fastening points of the reinforcing members 61 and 65 by the fastening member 69 are broken and the axial crushing of the front side frame 40 is started (the state shown in FIG. 12). The peak at the end of the fifth stroke period T5 indicates the timing (stroke amount) when the axial crushing of the front side frame 40 starts. In this fifth stroke period T5, the axial crushing of the front side frame 40 starts for the first time.

[0047] In the subsequent sixth stroke period T6, the load changes at a substantially constant value. The sixth stroke period T6 indicates the period during which the axial crushing of the front side frame 40 progresses (the state shown in FIG. 13). In this embodiment, since the front side frame 40 having a uniform cross section in the axial direction is axially crushed, the load that appears changes at a substantially constant value.

[0048] As described above, the vehicle body front structure 1 according to this embodiment includes a bumper beam 3, a front side frame 40 made of a fiber reinforced resin composite material, a crush box 20 made of a fiber reinforced resin composite material disposed between the bumper beam 3 and the front side frame 40, and a side frame joining member 30 that is disposed between the crush box 20 and the front side frame 40 and supports the crush box 20. Reinforcing members 61 and 65 provided in contact with the side frame joining member 30 or extending from the side frame joining member 30 are mechanically fastened to the end of the front side frame 40 on the side of the side frame joining member 30.

[0049] Therefore, when the load applied during a frontal collision is small, the crash box 20 can be axially crushed without fracturing the front side frame 40, thereby suppressing damage to the tip of the front side frame 40. Consequently, in the event of a minor collision, replacement of at least the front side frame 40 becomes unnecessary, reducing the effort and cost of parts replacement. On the other hand, when the applied collision load is large, the front side frame 40 can be axially crushed following the crash box 20, achieving efficient energy absorption performance.

[0050] Furthermore, in the front body structure 1 according to this embodiment, the load-bearing capacity of the fastening points between the front side frame 40 and the reinforcing members 61 and 65, which are fastened by mechanical means, is greater than the load that causes the crash box 20 to axially collapse. Therefore, it is possible to prevent the tip of the front side frame 40 from being damaged before the axial collapse of the crash box 20 begins.

[0051] Furthermore, the front body structure 1 according to this embodiment has a configuration in which the mechanically fastened front side frame 40 and reinforcing members 61 and 65 are held in a fastened state while the crash box 20 is crushed during a frontal collision of the vehicle, and then break when further load is applied. As a result, in the event of a minor collision, replacement of at least the front side frame 40 is unnecessary, thereby reducing the effort and cost of parts replacement. On the other hand, if the input collision load is large, the front side frame 40 can be axially crushed following the crash box 20, thereby achieving efficient energy absorption performance.

[0052] Furthermore, in the front body structure 1 according to this embodiment, the reinforcing members 61 and 65 are provided on at least the left and right sides of the front side frame 40, respectively. Therefore, when a collision load is applied, the load transmitted through the crash box 20 can be received in a balanced manner at the fastening points between the front side frame 40 and the reinforcing members 61 and 65. Consequently, it is possible to prevent the collision load from being unevenly transmitted to the front side frame 40 and causing damage to the leading edge of the front side frame 40.

[0053] Furthermore, in the front body structure 1 according to this embodiment, the reinforcing members 61 and 65 also have the function of supporting the support member 7 and the front cross member 9, which are other structural members of the vehicle. In other words, by using the brackets that support the support member 7 and the front cross member 9 as reinforcing members 61 and 65, it is possible to realize members that function as the reinforcing members 61 and 65 of this disclosure without increasing the number of parts.

[0054] While preferred embodiments of the technology of this disclosure have been described in detail above with reference to the attached drawings, the technology of this disclosure is not limited to these examples. It is clear to any person with ordinary skill in the art to which this disclosure pertains that various modifications or alterations may be conceived within the scope of the technical idea set forth in the claims, and these will naturally also be understood to fall within the technical scope of this disclosure.

[0055] 1: Front body structure 3: Bumper beam 5: Body frame 7: Support member 9: Front cross member 10: Crash box connecting member 20: Crash box 30: Side frame connecting member 31: Base 33: Cylindrical section 35: Reinforcement member 37: Reinforcement member 40: Front side frame 61: Reinforcement member 63: Hole 65: Reinforcement member 67: Groove 69: Fastening member

Claims

1. A front body structure comprising: a bumper beam; a front side frame made of fiber-reinforced resin composite material; a crash box made of fiber-reinforced resin composite material disposed between the bumper beam and the front side frame; and a support member disposed between the crash box and the front side frame to support the crash box, wherein a reinforcing member provided in contact with the support member or extending from the support member is mechanically fastened to the end of the front side frame on the support member side.

2. The front body structure according to claim 1, wherein the mechanically fastened front side frame and the reinforcing member are held in a fastened state while the crash box is crushed during a frontal collision of the vehicle, and break when further load is applied.

3. The front body structure according to claim 1, wherein the load-bearing capacity of the fastening points between the front side frame and the reinforcing member by mechanical fastening is greater than the load that causes the crash box to axially collapse.

4. The front body structure of a vehicle according to claim 1, wherein the reinforcing members are provided on at least the left and right sides of the front side frame.

5. The front body structure of a vehicle according to claim 1, wherein the reinforcing member also serves the function of supporting other structural members of the vehicle body.

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