Energy-absorbing structure

Abstract

An energy-absorbing structure disposed between a bumper beam of a vehicle body and a vehicle body frame comprises a cylindrical energy-absorbing member that collapses axially upon the input of a collision load so as to absorb the collision load. The energy-absorbing member is a fiber-reinforced resin absorption member that includes axial fibers disposed in the axial direction, and cross fibers wound along the direction intersecting the axial direction. The axial fibers comprise carbon fibers at a ratio greater than 50%, and the cross fibers comprise glass fibers at a ratio greater than 50%.

Description

Energy Absorption Structure

[0001] The present disclosure relates to energy absorbing structures.

[0002] Vehicles are equipped with energy absorbing members that collapse in the event of a collision to absorb the collision load. A typical example of an energy absorbing member is a cylindrical crash box that is placed between the bumper beam and the vehicle body frame. Conventional energy absorbing members have been made of metal materials such as steel, but in recent years, in order to reduce the weight of vehicle bodies, development has been progressing on energy absorbing members made of fiber-reinforced resins containing reinforcing fibers, such as carbon fiber.

[0003] JP 2017-001599 A

[0004] It is known that when an energy absorption member is constructed using carbon fiber, a common reinforcing fiber, the behavior of the load when the carbon fiber reinforced resin is gradually crushed is unstable. For this reason, it is not easy to determine the load at which not only the bumper and energy absorption member but also the body frame begins to break during a frontal or rear collision. This is particularly important not only for engine vehicles equipped with an engine as a driving force source, but also for electric vehicles using a drive motor as a driving force source.

[0005] In electric vehicles, energy absorption by bending fracture of body parts using an engine block, as in engine vehicles, cannot be expected, and from the perspective of weight reduction, efficient absorption of collision loads by axial crushing of fiber-reinforced resin energy absorption members is expected. Therefore, if the load behavior during axial crushing of fiber-reinforced resin energy absorption members can be stabilized, the usability as an energy absorption structure for engine vehicles and electric vehicles can be increased.

[0006] Therefore, the present disclosure has been made in consideration of the above problems, and an object of the present disclosure is to provide an energy absorption structure made of fiber-reinforced resin that can stabilize the behavior of load during axial crushing.

[0007] In order to solve the above problems, according to one aspect of the technology of the present disclosure, there is provided an energy absorbing structure that is arranged between a bumper beam of a vehicle body and a vehicle body frame, and that includes a tubular energy absorbing member that collapses in the axial direction when a collision load is input to absorb the collision load, wherein the energy absorbing member is an absorbing member made of fiber-reinforced resin that includes axial fibers arranged along the axial direction and cross fibers wound in a direction intersecting the axial direction, and the axial fibers include carbon fibers at a ratio of at least 50% or more, and the cross fibers include glass fibers at a ratio of at least 50% or more.

[0008] As described above, according to the technique of the present disclosure, it is possible to stabilize the load behavior during axial collapse of an energy absorption structure made of fiber-reinforced resin.

[0009] Fig. 1 is a schematic diagram showing an energy absorption structure according to the present embodiment; Fig. 2 is a cross-sectional view of the energy absorption structure according to the same embodiment; Fig. 3 is a perspective view of an energy absorbing member and a first support member according to the same embodiment; Fig. 4 is an explanatory diagram showing an example of the configuration of reinforcing fibers of the energy absorbing member according to the same embodiment; Fig. 5 is an explanatory diagram showing a modified example of the energy absorbing structure according to the same embodiment; Fig. 6 is an explanatory diagram showing the behavior of a load when the energy absorbing structure is axially collapsed; Fig. 7 is an explanatory diagram showing a modified example of the energy absorbing structure according to the same embodiment.

[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] Figures 1 to 3 are explanatory diagrams of an energy absorption structure 1 according to this embodiment. Figure 1 is a schematic diagram of the energy absorption structure 1 provided in the front portion of the vehicle, as viewed from above the vehicle. Figure 2 is a cross-sectional view of the energy absorption structure 1 shown in Figure 1, cut along the axial direction. The top of Figures 1 and 2 represents the front side of the vehicle, and the bottom represents the rear side of the vehicle. Figure 3 is a perspective view showing an energy absorption member 10 and a first support member 20 of the energy absorption structure 1. In the following description, the front side of the vehicle may be referred to as the leading end side, and the rear side of the vehicle may be referred to as the trailing end side.

[0012] The energy absorbing structure 1 includes an energy absorbing member 10, a first support member 20, and a second support member 30. A first end 11 of the energy absorbing member 10 on the front side of the vehicle is inserted into a recess 25 provided in the first support member 20 and is supported by the first support member 20. The first support member 20 is fixed to the bumper beam 3. A second end 15 of the energy absorbing member 10 on the rear side of the vehicle is inserted into a recess 35 provided in the second support member 30 and is supported by the second support member 30. The second support member 30 is fixed to a front end surface of a body frame 5 that extends in the longitudinal direction of the vehicle.

[0013] (Basic Structure of Energy Absorption Member) The energy absorbing member 10 is a cylindrical member whose axial direction is arranged along the longitudinal direction of the vehicle. When the vehicle collides with a preceding vehicle, an obstacle, or other obstacle, the energy absorbing member 10 receives a collision load and collapses axially, thereby absorbing the collision load. Furthermore, when the collision load is large, the energy absorbing member 10 also has a function of transmitting the load to the body frame 5.

[0014] In this embodiment, the energy absorbing member 10 is a hollow tubular member having a rectangular cross section perpendicular to the axial direction. However, the energy absorbing member 10 may also be a hollow tubular member having a circular cross section.

[0015] The dimensions of the energy absorbing member 10 are designed appropriately depending on the size of the vehicle, the amount of energy absorption to be obtained, the weight of the energy absorbing member 10, etc. For example, the axial length of the energy absorbing member 10 is 100 to 200 mm, the diameter of the inner space is 40 to 70 mm, and the thickness of the surrounding wall portion is 3 to 5 mm. Note that the dimensions of the energy absorbing member 10 may be outside the range of the above example.

[0016] The energy absorbing member 10 is a molded product made of fiber-reinforced resin containing at least carbon fiber, glass fiber, and a matrix resin, and is therefore both strong and lightweight. When a collision load is input, the fiber-reinforced resin energy absorbing member 10 generates load through axial crushing while continuously breaking, achieving stable energy absorption characteristics with little load fluctuation. Furthermore, the fiber-reinforced resin energy absorbing member 10 has the characteristics of having little residual crushing and absorbing a large amount of energy per unit weight.

[0017] The energy absorbing member 10 can be manufactured by weaving a plurality of continuous fibers, integrating them with a matrix resin, and curing the weaved fibers. The reinforcing fibers used in the energy absorbing member 10 may include organic fibers such as ceramic fibers and aramid fibers in addition to carbon fibers and glass fibers.

[0018] The matrix resin used in the energy absorbing member 10 may be a thermosetting resin or a thermoplastic resin. 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. When these thermosetting resins are used as the matrix resin, appropriate curing agents and reaction accelerators may be added.

[0019] 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.

[0020] At the first end 11 of the energy absorbing member 10, where input of a collision load is expected, the inner circumferential surface 19 of the energy absorbing member 10 has a tapered shape that expands in diameter toward the end face 13. Therefore, the strength of the first end 11 in the axial direction of the energy absorbing member 10 is relatively reduced. Therefore, when an axial load is input to the energy absorbing member 10, fracture is induced from the first end 11.

[0021] (Axial Fibers and Cross Fibers) FIG. 4 is an explanatory diagram showing an enlarged view of the configuration of the reinforcing fibers of the cylindrical energy absorbing member 10. As shown in FIG.

[0022] The energy absorbing member 10 includes axial fibers 41 arranged along the axial direction and cross fibers (also called helical fibers) 43a, 43b wound in a direction intersecting the axial direction. The cross fibers 43a, 43b are wound in directions inclined to the left and right with respect to the axial direction. Such an energy absorbing member 10 can be manufactured, for example, by weaving a plurality of continuous fibers by a braiding method, integrating the fibers with a matrix resin, and curing the weave.

[0023] The method for forming the reinforcing fibers including the axial fibers 41 and the cross fibers 43a, 43b into a hollow cylindrical shape is not limited to the braiding method, and other methods such as the filament winding method can also be used.

[0024] The axial fibers 41 have the function of providing rigidity against a load input in the axial direction. The cross fibers 43 have the function of providing rigidity against a load input obliquely to the axial direction. By adjusting the number and density of the axial fibers 41 and the cross fibers 43, the amount of energy absorption by the energy absorbing member 10 can be designed as desired.

[0025] In this embodiment, the axial fibers 41 and cross fibers 43a, 43b constituting the energy absorbing member 10 are each made of strip-shaped fibers in which a plurality of fibers are arranged in a direction perpendicular to the direction in which the fibers extend.

[0026] The axial fibers 41 contain carbon fibers at a ratio of at least 50%. In this embodiment, the ratio of carbon fibers to the multiple fibers constituting the strip-shaped axial fibers 41 is at least 50%. Carbon fibers have greater bending rigidity against load in the fiber direction than glass fibers and other fibers. Therefore, by configuring the axial fibers 41 mainly from carbon fibers, the axial load capacity of the energy absorbing member 10 can be increased. The carbon fiber ratio may be in the range of more than 50% and not more than 100%, and the higher the carbon fiber ratio, the higher the axial load capacity of the energy absorbing member 10.

[0027] The cross fibers 43a, 43b contain glass fibers at a ratio of at least 50%. In this embodiment, the ratio of glass fibers to the multiple fibers constituting the strip-shaped cross fibers 43a, 43b is at least 50%. Glass fibers have greater bending rigidity against loads in a direction perpendicular to the fiber direction than carbon fibers. Therefore, by configuring the cross fibers 43a, 43b mainly from glass fibers, the energy absorption capacity of the energy absorbing member 10 can be increased. The ratio of glass fibers may be in the range of more than 50% and not more than 100%, and the higher the ratio of glass fibers, the greater the energy absorption capacity of the energy absorbing member 10.

[0028] (First Support Member) The first support member 20 is disposed opposite the end surface 13 of the first end 11 of the energy absorbing member 10 to which the input of a collision load is expected, and is fixed to the bumper beam 3 to support the first end 11. The first support member 20 is a molded part made of a metal material such as steel or aluminum, and is fixed to the bumper beam 3 by fastening members such as bolts (not shown) or by welding.

[0029] The first support member 20 has a base 21, a tubular portion 23, and a recess 25. The base 21 is a plate-shaped portion that serves as the base of the first support member 20 and is fixed to the bumper beam 3. The tubular portion 23 extends from the base 21 in a direction along the axial direction of the energy absorbing member 10. The recess 25 is formed inside the base 21 and the tubular portion 23, and has an inner circumferential surface that fits into the outer circumferential surface 11a of the first end portion 11 of the energy absorbing member 10.

[0030] The recess 25 has an inner peripheral surface 25a that surrounds the first end 11 of the energy absorbing member 10 and is bonded to the outer peripheral surface 11a of the first end 11 with an adhesive 27. In other words, the first support member 20 is bonded to the first end 11 of the energy absorbing member 10 with the adhesive 27. The rigidity of the adhesive 27 is smaller than the rigidity of the first support member 20 and the energy absorbing member 10, and when a collision load is input to the first support member 20 via the bumper beam 3, the adhesive 27 undergoes shear failure at an early stage.

[0031] A gap S is provided between the end face 13 of the first end 11 of the energy absorbing member 10 and the bottom surface 25b of the recess 25. Therefore, until the collision load input to the first support member 20 via the bumper beam 3 exceeds a predetermined load, the bottom surface 25b of the recess 25 of the first support member 20 and the end face 13 of the first end 11 of the energy absorbing member 10 are maintained apart. Furthermore, when the collision load input to the first support member 20 via the bumper beam 3 exceeds the predetermined load, the bottom surface 25b of the recess 25 of the first support member 20 comes into contact with the end face 13 of the first end 11 of the energy absorbing member 10, and axial collapse of the energy absorbing member 10 begins.

[0032] The load at which the bottom surface 25b of the recess 25 of the first support member 20 comes into contact with the end surface 13 of the first end 11 of the energy absorbing member 10 is the sum of the load that can cause shear failure of the adhesive 27 plus the load that can move the first support member 20 the length of the gap S. Therefore, by adjusting the rigidity of the adhesive 27 and the length of the gap S, it is possible to adjust the load at which axial collapse of the energy absorbing member 10 begins.

[0033] Furthermore, corners 25c connecting the inner peripheral surface 25a and the bottom surface 25b of the first support member 20 are curved. Therefore, when axial crushing of the energy absorbing member 10 starts from the first end 11 due to the collision load input via the first support member 20, the first end 11 is prevented from spreading outward as it is crushed, and the broken energy absorbing member 10 can be axially crushed while being rolled inward.

[0034] It should be noted that the first support member 20 may not have a tubular portion 23 and a recess 25 may be provided in the base 21, but when forming a recess 25 of the same depth, the first support member 20 can be made lighter by providing a tubular portion 23 and forming a recess 25 inside the base 21 and the tubular portion 23.

[0035] As described above, at the first end 11 of the energy absorbing member 10, where input of a collision load is expected, the inner circumferential surface 19 has a tapered shape that expands in diameter toward the end face 13. To induce fracture from the first end 11 when an axial load is input to the energy absorbing member 10, the outer circumferential surface 11a of the first end 11 of the energy absorbing member 10 may be reduced in diameter toward the end face 13. However, as shown in Figure 5, when the outer circumferential surface 11a of the first end 11 of the energy absorbing member 10 is reduced in diameter, the reduced diameter portion is separated from the inner circumferential surface 25a of the recess 25 of the first support member 20 (see the right side of Figure 5). Therefore, in order to make the adhesive area between the outer surface 11a of the first end 11 of the energy absorbing member 10 and the inner surface 25a of the recess 25 of the first support member 20 the same, the length (height) h2 of the tubular portion 23 must be greater than the length (height) h1 of the tubular portion 23 when the inner surface 19 of the energy absorbing member 10 is reduced in diameter.

[0036] Therefore, by providing the inner surface 19 of the energy absorption member 10 with a tapered shape that expands in diameter toward the end face 13 and configuring the outer diameter of the outer surface 11a of the first end 11 to remain unchanged, the joining strength can be maintained without increasing the length of the tubular portion 23 of the first support member 20, and the first support member 20 can be made lighter.

[0037] (Second Support Member) The second support member 30 is disposed opposite the end face 17 of the second end 15 on the rear end side of the energy absorbing member 10, and is fixed to the end face of the body frame 5 on the front side of the vehicle to support the second end 15. The second support member 30 is a molded product made of a metal material such as steel or aluminum, and is fixed to the body frame 5 by fastening members such as bolts (not shown), welding, or the like.

[0038] The second support member 30 has a base 31, a tubular portion 33, and a recess 35. The base 31 is a plate-shaped portion that serves as the base of the second support member 30, and is fixed to the body frame 5. The tubular portion 33 extends from the base 31 in a direction along the axial direction of the energy absorbing member 10. The recess 35 is formed inside the tubular portion 33, and has an inner circumferential surface that fits into the outer circumferential surface of the second end portion 15 of the energy absorbing member 10.

[0039] The recess 35 has an inner circumferential surface 35a that surrounds the second end 15 of the energy absorbing member 10 and is bonded to the outer circumferential surface 15a of the second end 15 with an adhesive 37. In other words, the second support member 30 is bonded to the second end 15 of the energy absorbing member 10 with the adhesive 37.

[0040] An end surface 17 of the second end portion 15 of the energy absorbing member 10 is disposed in contact with a bottom surface 35b of the recess 35 of the second support member 30. When an axial collision load is applied to the energy absorbing member 10, the second support member 30 has the function of receiving the load and causing axial crushing of the energy absorbing member 10. Therefore, there are no particular limitations on the adhesive 37 as long as it has enough rigidity to withstand vehicle vibrations and the like.

[0041] It should be noted that the second support member 30 may not have a tubular portion 33 and may have a recess 35 provided in the base 31, but when forming a recess 35 of the same depth, the second support member 30 can be made lighter by providing a tubular portion 33 and forming the recess 35 inside the tubular portion 33.

[0042] (Load Characteristics) The configuration of the energy absorption structure 1 according to this embodiment has been described so far. Next, the load characteristics of the energy absorption structure 1 will be described.

[0043] Figure 6 shows the load characteristics of energy absorbing members 10 made of different types of reinforcing fibers. The load characteristics show the behavior of the load when the rear end of the energy absorbing member 10 is fixed to a support and an axial surface load is applied from the front end to the rear end of the energy absorbing member 10. The horizontal axis shows the stroke amount (axial collapse length) of the energy absorbing member 10, and the position at which axial collapse of the energy absorbing member 10 begins is represented as zero. The vertical axis shows the developed load. In the load characteristics shown in Figure 6, the sum of the loads at each stroke amount up to a certain stroke amount indicates the amount of energy absorbed when the energy absorbing member 10 axially collapses up to that stroke amount.

[0044] The energy absorbing member 10 of the example is an energy absorbing member 10 in which the axial fibers 41 are 100% carbon fiber and the cross fibers 43a, 43b are 100% glass fiber. The energy absorbing member 10 of Reference Example 1 is an energy absorbing member in which the axial fibers and cross fibers are both 100% carbon fiber. The energy absorbing member of Reference Example 2 is an energy absorbing member in which the axial fibers and cross fibers are both 100% glass fiber.

[0045] In the energy absorption members 10 of the Example and Reference Examples 1 and 2, the load rises sharply immediately after the start of axial collapse of the energy absorption member 10. In the energy absorption members 10 of the Examples, the behavior of the load change accompanying the progression of axial collapse (increase in stroke amount) of the energy absorption member 10 is relatively stable. Stable behavior of the load change means that the up and down fluctuations in the load are small.

[0046] The energy absorption member 10 of Reference Example 1, which includes an energy absorption member in which both the axial fibers and the cross fibers are 100% carbon fiber, exhibits a larger load peak than the energy absorption member 10 of the Examples. However, the behavior of the load change associated with the progression of axial collapse of the energy absorption member 10 (increase in stroke amount) is not stable. This is because the bending rigidity of the carbon fibers is relatively low with respect to loads in the direction transverse to the fiber direction. If the behavior of the load change is not stable, it becomes difficult to design the axial collapse amount of the energy absorption member 10 according to the collision load input to the energy absorption member 10. For this reason, it becomes necessary to design the energy absorption amount of the energy absorption member 10 on the safe side (in the direction of increasing energy absorption amount), for example.

[0047] Furthermore, the energy absorption member 10 of Reference Example 2, in which both the axial fibers and the cross fibers are 100% glass fiber, exhibits a smaller load peak than the energy absorption member 10 of the Examples, and the behavior of the load change associated with the progression of axial collapse of the energy absorption member 10 (increasing stroke amount) is not stable. This is due to the fact that both the axial fibers and the cross fibers lack rigidity and are prone to buckling. Therefore, it is difficult to design the axial collapse amount of the energy absorption member 10 in accordance with the collision load input to the energy absorption member 10. Therefore, it is necessary to design the energy absorption amount of the energy absorption member 10 on the safe side (to increase the energy absorption amount), for example. Furthermore, from the perspective of minimizing the occurrence of destruction of the body frame 5, it is necessary to design the energy absorption amount to increase, for example, by increasing the size of the energy absorption member 10 or the thickness of the wall portion.

[0048] In contrast, the energy absorption member 10 of the embodiment has a smaller load peak than the energy absorption member 10 of Reference Example 1, but a larger load peak than the energy absorption member 10 of Reference Example 2, and the behavior of the load change associated with the progression of axial collapse of the energy absorption member 10 (increase in stroke amount) is stable.

[0049] As can be seen from the load characteristics shown in Figure 6, by having the axial fibers 41 contain at least 50% carbon fiber and the cross fibers 43a, 43b contain at least 50% glass fiber, it is possible to stabilize the behavior of load changes while suppressing a significant decrease in the peak load. This makes it relatively easy to design the axial crushing capacity of the energy absorption member 10 according to the collision load input to the energy absorption member 10, allowing for precise design of the energy absorption capacity. Furthermore, by being able to predict the energy absorption capacity, it is possible to set a target for part replacement according to the collision load.

[0050] To reduce the degree of decrease in the peak load, the axial fibers 41 preferably contain carbon fibers at a ratio of at least 70% or more, and more preferably 100%. To stabilize the behavior of load changes, the cross fibers 43a, 43b preferably contain glass fibers at a ratio of at least 50% or more, and more preferably 100%.

[0051] 7 shows the load characteristics of the energy absorbing structure 1 according to the example of this embodiment. While the load characteristics shown in Fig. 6 are those of the energy absorbing member 10, the load characteristics shown in Fig. 7 are those of the energy absorbing structure 1 in which the first support member 20 is joined to the first end 11 of the energy absorbing member 10.

[0052] In the energy absorbing structure 1 of this embodiment, a relatively small peak load occurs before the energy absorbing member 10 begins to axially collapse. This increase in load indicates that the adhesive 27 bonding the energy absorbing member 10 and the first support member 20 is shear-fractured by the collision load. Furthermore, in the energy absorbing structure 1 of the example, a gap S is provided between the end face 13 of the first end 11 of the energy absorbing member 10 and the bottom surface 25b of the recess 25 of the first support member 20. Therefore, even after shear failure of the adhesive 27 occurs, a load sufficient to move the first support member 20 in the axial direction by the length of the gap S occurs.

[0053] Therefore, in the energy absorption structure 1 of this embodiment, a predetermined amount of energy is absorbed before the energy absorbing member 10 begins to axially collapse. In a configuration without the gap S, a portion of the energy absorbing member 10 would break even in a collision with a relatively small collision load, requiring replacement of not only the bumper beam 3 but also the energy absorbing member 10. In this case, dust from the broken energy absorbing member 10 would fly, which could affect electrical components installed in the vehicle.

[0054] On the other hand, in the case of the energy absorption structure 1 of this embodiment, in the event of a collision with a relatively small collision load, the collision load can be absorbed without causing axial crushing of the energy absorption member 10. As a result, there is no risk of dust from the energy absorption member 10 flying around when replacing the bumper beam 3, and the impact on electrical components can be reduced.

[0055] Furthermore, the energy absorption structure 1 of this embodiment is configured so that, when axial collapse of the energy absorption members 10 begins, the broken energy absorption members 10 are rolled inward as they undergo axial collapse. Therefore, when the axial collapse of the energy absorption members 10 progresses to a predetermined stroke amount (stroke amount = 100 mm in FIG. 7 ), the broken energy absorption members 10 fill the space inside the energy absorption members 10. As a result, as the axial collapse of the energy absorption members 10 continues to progress, the load increases in a nearly linear manner. This makes it easier to design the collision load at which the body frame 5 begins to collapse.

[0056] Although the 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.

[0057] For example, in the above embodiment, at least one of the first support member and the second support member may have an air vent in the bottom surface of the recess, which connects the recess to the outside of the base. By providing the air vent in the first support member or the second support member, air can be discharged from the space inside the energy absorbing member 10 to the outside when the energy absorbing member 10 undergoes axial collapse. This reduces the resistance caused by the pressure in the space inside the energy absorbing member 10 as the axial collapse of the energy absorbing member 10 progresses, allowing the energy absorbing member 10 to absorb energy according to its design.

[0058] When an air vent is provided in the first support member, the air vent is configured to pass through the interior of the bumper beam or between the first support member and the bumper beam and be discharged to the outside.

[0059] In the above embodiment, the cross-sectional shape of the energy absorbing member 10 is rectangular, but the cross-sectional shape of the energy absorbing member 10 is not limited to rectangular. For example, the cross-sectional shape may be a polygon such as a hexagon or an octagon other than a circle.

[0060] DESCRIPTION OF SYMBOLS 1: Energy absorption structure 3: Bumper beam 10: Energy absorption member 11: First end portion 13: End face 15: Second end portion 19: Inner peripheral surface 20: First support member 21: Base portion 23: Cylindrical portion 25: Recessed portion 25a: Inner peripheral surface 25b: Bottom surface 25c: Corner portion 27: Adhesive 41: Axial fiber 43: Cross fiber 43a: Cross fiber 43b: Cross fiber S: Gap

Claims

1. An energy absorbing structure arranged between a bumper beam of a vehicle body and a vehicle body frame, comprising a tubular energy absorbing member that collapses in the axial direction when a collision load is input to absorb the collision load, said energy absorbing member being an absorbing member made of fiber-reinforced resin containing axial fibers arranged along the axial direction and cross fibers wound in a direction intersecting the axial direction, said axial fibers containing carbon fibers at a ratio of at least 50% or more, and said cross fibers containing glass fibers at a ratio of at least 50% or more.

2. The energy absorbing structure described in claim 1, wherein the axial fibers and the cross fibers are each strip-shaped fibers having a plurality of fibers arranged in a direction intersecting the extension direction of the fibers, the carbon fibers account for at least 50% of the plurality of fibers constituting the strip-shaped axial fibers, and the glass fibers account for at least 50% of the plurality of fibers constituting the strip-shaped cross fibers.

3. An energy absorbing structure as described in claim 1 or 2, further comprising a metal support member arranged opposite an end face of a first end of the energy absorbing member to which the collision load is expected to be input and fixed to the bumper beam to support the first end, wherein the support member has a recess having an inner peripheral surface surrounding the first end and bonded to the outer peripheral surface of the first end with an adhesive.

4. The energy absorbing structure of claim 3, further comprising a gap between an end face of said first end and a bottom surface of said recess.

5. The energy absorbing structure according to claim 4, wherein a corner portion connecting the inner peripheral surface and the bottom surface of the recess is formed of a curved surface.

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