Load-receiving member for vehicle

Abstract

A main input direction of a load to be absorbed is defined as a first direction, one direction intersecting the first direction is defined as a second direction, and another direction intersecting the first direction and the second direction is defined as a third direction. This load-receiving member for a vehicle comprises a first wall extending substantially along the first direction and the second direction, and a second wall extending substantially along the first direction and the third direction. The first wall and the second wall form an open cross section that is open in a direction intersecting the first direction. When viewed from the second direction, the first wall has a first uneven section protruding in an alternating manner to one side and the other side in the third direction toward the first direction. When viewed from the third direction, the second wall has a second uneven section protruding in an alternating manner to one side and the other side in the second direction toward the first direction. Break-inducing sections are provided at a plurality of locations in the first direction of the first uneven section and the second uneven section.

Description

Vehicle load-bearing members

[0001] The present invention relates to a load-receiving member for a vehicle that absorbs the energy of an input impact load.

[0002] A vehicle front structure has been proposed in which a load receiving portion (energy absorbing portion) is integrally formed with a part of a wheel house (see, for example, Patent Document 1).

[0003] The vehicle front structure described in Patent Document 1 has a load receiving portion (energy absorbing portion) that is integrally formed on the upper wall of a wheelhouse made of aluminum alloy and extends substantially along the longitudinal direction of the vehicle. The load receiving portion has a plurality of substantially C-shaped reinforcing ribs formed on the inner surface of a channel-shaped beam that extends substantially along the longitudinal direction of the vehicle and that are spaced apart in the longitudinal direction of the vehicle.

[0004] In this load-receiving portion, sections with and without approximately C-shaped reinforcing ribs are alternately arranged on the inner surface of the beam, so that when an impact load is input from the front, the sections without reinforcing ribs can collapse like bellows. Therefore, this load-receiving portion can efficiently absorb the energy of the impact load by collapsing like bellows in the sections without reinforcing ribs.

[0005] US Patent Application Publication No. 2023 / 0373563

[0006] The load-receiving portion described in Patent Document 1 has multiple reinforcing ribs (thickened portions) intermittently formed on the inner surface of the beam portion, thereby alternately providing high-rigidity and low-rigidity portions along the longitudinal direction of the beam portion. Therefore, when the beam portion is crushed by the input of an impact load, the reinforcing ribs tend to increase the remaining crushed portion of the beam portion. In this case, it is possible to obtain sufficient energy absorption by increasing the length of the energy absorption portion (beam portion) of the load-receiving member, but depending on the design and specifications of the vehicle, it may be difficult to ensure a sufficient length of the energy absorption portion.

[0007] The problem to be solved by the present invention is to suppress the remaining crushing of the load-receiving member when an impact load is input and to ensure a sufficient energy absorption stroke. By solving this problem, the present invention aims to improve collision safety performance.

[0008] A load-receiving member according to one aspect of the present invention is characterized in that, when the main input direction of the load to be absorbed is defined as a first direction, a direction intersecting the first direction as a second direction, and another direction intersecting the first and second directions as a third direction, the load-receiving member comprises a first wall extending approximately along the first and second directions, and a second wall extending approximately along the first and third directions, wherein the first and second walls form an open cross section that is open in a direction intersecting the first direction, the first wall has a first uneven portion that, when viewed from the second direction, alternately protrudes to one side and the other side of the third direction toward the first direction, and the second wall has a second uneven portion that, when viewed from the third direction, alternately protrudes to one side and the other side of the second direction toward the first direction, and fracture induction portions are provided at multiple locations in the first direction of the first uneven portion and the second uneven portion.

[0009] With the above configuration, when an impact load is applied in the first direction, the load is transmitted to the first uneven portion of the first wall and the second uneven portion of the second wall. Because the first uneven portion and the second uneven portion have fracture inducing portions at multiple locations in the first direction, the first uneven portion and the second uneven portion are sequentially deformed and fractured at multiple locations starting from the fracture inducing portions. The fractured fragments of the first uneven portion and the second uneven portion are sequentially ejected and do not remain as crushed fragments as the deformation of the load-receiving member progresses. Therefore, when this configuration is adopted, it is possible to ensure a sufficient energy absorption stroke while suppressing an increase in the overall length of the load-receiving member. Furthermore, because the load-receiving member has an open cross-sectional shape that is open in a direction intersecting the first direction, fragments that break and fall upon application of the impact load are smoothly ejected outside the open cross-section without remaining inside the load-receiving member. Therefore, when this configuration is adopted, it is possible to further suppress the remaining crushed fragments of the load-receiving member.

[0010] It is desirable that the first uneven portion of the first wall, when viewed from the second direction, has a first convex portion that protrudes in a direction away from the second wall and a first concave portion that is recessed in a direction approaching the second wall, and that the second uneven portion of the second wall, when viewed from the third direction, has a second convex portion that protrudes in a direction away from the first wall and a second concave portion that is recessed in a direction approaching the first wall, and that the first convex portion and the second convex portion, and the first concave portion and the second concave portion, are each arranged at approximately the same position in the first direction.

[0011] In this case, when an impact load is input, the input load is likely to be transmitted to the corresponding portions of the first and second uneven portions at the same time. Therefore, by arranging fracture inducing portions in the corresponding portions of the first and second uneven portions, it is possible to deform and fracture the corresponding portions of the first and second uneven portions at the same time. As a result, it is possible to more smoothly proceed the deformation and fracture of the load-receiving member.

[0012] The first uneven portion of the first wall, when viewed from the second direction, has a first convex portion protruding in a direction away from the second wall and a first concave portion recessed in a direction approaching the second wall, and the second uneven portion of the second wall, when viewed from the third direction, has a second convex portion protruding in a direction away from the first wall and a second concave portion recessed in a direction approaching the first wall, the first convex portion having a first small cross-sectional modulus portion having a smaller cross-sectional modulus in the third direction than the first concave portion, and the second convex portion having a second small cross-sectional modulus portion having a smaller cross-sectional modulus in the second direction than the second concave portion, the first small cross-sectional modulus portion constituting the fracture inducing portion in the first uneven portion, and the second small cross-sectional modulus portion constituting the fracture inducing portion in the second uneven portion.

[0013] In this case, in each concave-convex portion, small section modulus portions (first small section modulus portion and second small section modulus portion) having a smaller section modulus than the concave portions (first concave portion and second concave portion) are provided in the convex portions (first convex portion and second convex portion). Therefore, when an impact load is input to the load-receiving member, the convex portions with the smaller section modulus deform and fracture first. Furthermore, when this configuration is adopted, by appropriately setting and adjusting the section modulus of the first convex portion and the second convex portion, it is possible to easily control the deformation and fracture behavior of the load-receiving member without providing thick portions such as reinforcing ribs.

[0014] The thickness of the most recessed portion of the first recess may be set to be thicker than the thickness of the first protrusion, and the thickness of the most recessed portion of the second recess may be set to be thicker than the thickness of the second protrusion.

[0015] In this case, by changing the section modulus of each portion of each concave / convex portion by setting the wall thickness, it is possible to set a first small section modulus portion or a second small section modulus portion for each convex portion and make the most depressed portion of each concave portion less likely to deform (increase the section modulus). Furthermore, by setting the section modulus of each convex portion to be small and the section modulus of the most depressed portion of each concave portion to be large, when an impact load is input, the load is received by the concave portion adjacent to the convex portion to which the load is first input, making the convex portion more likely to fracture. Furthermore, the depressed portion that is less likely to deform can smoothly transmit the load to the next convex portion. Therefore, by adopting this configuration, it is possible to smoothly progress the fracture of the convex portions in the load input direction.

[0016] The most protruding portion of the first convex portion may be the first small section modulus portion, and the most protruding portion of the second convex portion may be the second small section modulus portion.

[0017] In this case, when an impact load is applied, deformation and fracture begin from the most protruding part of each convex portion. Therefore, when this configuration is adopted, adjacent convex portions are fractured evenly, making it less likely that remaining pieces or fragments will remain.

[0018] The open cross section defined by the first wall and the second wall is preferably made of a cast part made of an aluminum alloy.

[0019] In this case, the breaking strength is lower than when the open cross section formed by the first and second walls is made of iron-based metal, making it more likely to fracture when an impact load is applied. Therefore, it is less likely that the open cross section will remain uncrushed or leave fragments. Furthermore, in this configuration, because the open cross section formed by the first and second walls is formed by casting, it is easier to adjust the section modulus (wall thickness) of each part.

[0020] At the corner where the first wall and the second wall are connected, convex portions continuing from the first convex portion and the second convex portion and concave portions continuing from the first concave portion and the second concave portion may be arranged alternately along the first direction.

[0021] In this case, since the convex and concave portions are alternately arranged along the first direction at the corners between the first and second walls, the convex and concave portions function as reinforcing beads that prevent the first and second walls from collapsing. Therefore, when this configuration is adopted, it is possible to increase the strength and rigidity of the load-receiving member during normal use.

[0022] It is desirable that the distance in the first direction between the most protruding portion of the first convex portion and the most recessed portion of the first recess be set narrower than the dimension in the second direction at the most protruding portion of the first convex portion, and that the distance in the first direction between the most protruding portion of the second convex portion and the most recessed portion of the second recess be set narrower than the dimension in the third direction at the most protruding portion of the second convex portion.

[0023] In this case, the distance in the first direction between the most protruding portion of the convex portion and the most recessed portion of the concave portion is set narrower than the dimension in the extension direction of the most protruding portion of the convex portion, so that when an impact load is input, the load-receiving member can be crushed into small pieces along the convex and concave portions. Therefore, when this configuration is adopted, the amount of energy absorbed by the deformation and crushing of the convex and concave portions can be increased.

[0024] It is desirable that the most protruding portion of the first convex portion of the first wall and the most recessed portion of the first recess are connected by a flat surface, and the most protruding portion of the second convex portion of the second wall and the most recessed portion of the second recess are connected by a flat surface, and that the opening angle between two adjacent flat surfaces of the first wall in the first direction and the opening angle between two adjacent flat surfaces of the second wall in the first direction are both set to form an obtuse angle.

[0025] In this case, the opening angle between two adjacent flat surfaces in the first direction of the first wall and the opening angle between two adjacent flat surfaces in the first direction of the second wall are both set to obtuse angles, so that it is possible to effectively achieve both the transmission of load in the first direction when an impact load is input and fracture starting from the fracture-inducing portion.

[0026] The load-receiving member according to one aspect of the present invention can, upon input of an impact load, sequentially deform and fracture multiple locations of the first and second concave-convex portions, starting from the fracture inducing portion. Therefore, when the load-receiving member according to this aspect is adopted, residual crushing upon input of an impact load can be suppressed, and a sufficient energy absorption stroke can be ensured.

[0027] 1 is a perspective view of a front part of a vehicle according to an embodiment; a perspective view of a front part of a vehicle, with some members of FIG. 1 shown in virtual lines; a front view of a load receiving member according to an embodiment, as seen from the front side of the vehicle; a cross-sectional view of the load receiving member according to an embodiment, taken along line IV-IV of FIG. 3; a view of the load receiving member according to an embodiment, as seen from the arrow V of FIG. 4; a schematic longitudinal cross-sectional view of the load receiving member according to an embodiment; a schematic side view of the load receiving member according to an embodiment, corresponding to the view of arrow VII of FIG. 6; a schematic bottom view of the load receiving member according to an embodiment, corresponding to the view of arrow VIII of FIG. 6; a view illustrating a cross-section (a) of the load receiving member according to an embodiment, taken along the first direction and the third direction, and a cross-section (b) of the load receiving member according to an embodiment, taken along the first direction and the second direction; cross-sectional views (a) to (c) sequentially showing the deformation behavior of the load receiving member according to an embodiment when an impact load is input; a cross-sectional view showing a first modified example of the load receiving member; a cross-sectional view showing a second modified example of the load receiving member; a cross-sectional view showing a third modified example of the load receiving member.

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, unless otherwise specified, the terms "front, rear, up, down, left, right" and "rear" refer to the front, rear, up, down, left, right and left of the vehicle 1. In addition, in the drawings, the arrow FR points forward of the vehicle 1, the arrow UP points upward of the vehicle 1, and the arrow LH points to the left side of the vehicle 1.

[0029] FIG. 1 is a perspective view of the front portion of a vehicle 1 according to this embodiment. FIG. 2 is a perspective view similar to FIG. 1 , showing some components (load-receiving members 20, described later) in phantom lines. Reference numeral 10 in FIGS. 1 and 2 denotes a pair of damper housings spaced apart on both the left and right sides of a front compartment 11 in front of the driver's seat. The damper housings 10 are cylindrical and have a top wall, and the top wall supports the upper portions of dampers (not shown) of the front suspension. The left and right damper housings 10 are connected to a base block 12 extending along the vehicle width direction. The base block 12 is joined to left and right vehicle body frameworks in front of the driver's seat. Support brackets 13 extend from the undersides of the left and right sides of the base block 12 to swingably support the corresponding left and right front wheels W. In this embodiment, the base block 12 and the left and right damper housings 10 form a suspension support structure 15.

[0030] A load-receiving member 20 extending substantially along the vehicle longitudinal direction is connected to the front side of each of the left and right damper housings 10. The left and right load-receiving members 20 are formed substantially symmetrically. The load-receiving members 20 are made of cast parts made of aluminum alloy.

[0031] The left and right side edges of a bumper beam 14 disposed at the front of the vehicle 1 are connected to the front surfaces of the left and right load-receiving members 20 near the bottom. The bumper beam 14 extends horizontally substantially along the vehicle width direction, and the back surfaces (rear surfaces) of the left and right side edges are connected to the front ends of the corresponding load-receiving members 20.

[0032] FIG. 3 is a front view of the load-receiving member 20 as seen from the front side of the vehicle, and FIG. 4 is a cross-sectional view of the load-receiving member 20 taken along line IV-IV in FIG. 3. As shown in these figures, the load-receiving member 20 includes a first open cross-sectional portion 21, which is a plate-shaped wall portion extending generally along the vehicle longitudinal direction and bent in a crank-like manner in the vertical and horizontal directions, and a second open cross-sectional portion 22, which is a plate-shaped wall portion extending generally along the vehicle longitudinal direction and bent in a crank-like manner in the vertical and horizontal directions, and which is similarly arranged. The second open cross-sectional portion 22 is positioned above the first open cross-sectional portion 21 and outboard in the vehicle width direction. The bent shapes of the first open cross-sectional portion 21 and the second open cross-sectional portion 22 may be generally L-shaped or channel-shaped, or may include a partially curved portion.

[0033] A plate-shaped load input wall 23 extending in a direction intersecting (substantially perpendicular to) the vehicle longitudinal direction is provided at the front end of the first open cross-sectional portion 21. The bumper beam 14 is fastened and fixed to the front surface of the load input wall 23. A plate-shaped lower load transmission wall 24 extending in a direction intersecting (substantially perpendicular to) the vehicle longitudinal direction is provided at the rear end of the first open cross-sectional portion 21. The rear surface of the lower load transmission wall 24 is fastened and fixed to the lower front surface of the side portion of the base block 12 (the front surface of a second load receiving wall 25 described later). The load input wall 23 is disposed at a portion of the front end of the first open cross-sectional portion 21 that overlaps at least the joint portion of the bumper beam 14 in the vertical direction. The load input wall 23 may be formed to straddle the front end of a connecting wall portion 28 (described later) above the first open cross-sectional portion 21.

[0034] Additionally, a plate-shaped upper load transmission wall 26 (load transmission wall) extending in a direction intersecting (substantially perpendicular to) the vehicle longitudinal direction is provided at the rear end of the second open cross-sectional portion 22. The rear surfaces of the upper load transmission walls 26 are fastened and fixed to the front surfaces of the corresponding left and right damper housings 10 (front surfaces of first load receiving walls 27, described below). The upper load transmission wall 26 (load transmission wall) is disposed at a portion of the rear end of the second open cross-sectional portion 22 that overlaps at least the joint portion (first load receiving wall 27) of the suspension support structure 15 in the up-down direction.

[0035] The lower first open cross-sectional portion 21 and the upper second open cross-sectional portion 22 are connected by a plate-shaped connecting wall portion 28. The connecting wall portion 28 continuously connects the first open cross-sectional portion 21, which is located below on the inner side in the vehicle width direction, to the second open cross-sectional portion 22, which is located above on the outer side in the vehicle width direction, in the front-to-rear direction of the vehicle. The second open cross-sectional portion 22 and the first open cross-sectional portion 21, together with the connecting wall portion 28, form part of a front wheel house that covers the inner side of the front wheels W in the vehicle width direction.

[0036] Here, the front surface of the upper region of the base block 12 that constitutes the suspension support structure 15 and the front surfaces of the left and right damper housings 10 are continuous flat surfaces that face the front side of the vehicle. A portion of these flat surfaces constitutes the front surface of the first load receiving wall 27 to which the upper load transmission wall 26 at the rear of the load receiving member 20 is joined in surface contact. The front surfaces of the lower sides of the left and right side portions of the base block 12 also have flat surfaces that face the front side of the vehicle. These flat surfaces constitute the front surface of the second load receiving wall 25 to which the lower load transmission wall 24 at the rear of the load receiving member 20 is joined in surface contact. The first load receiving wall 27 to which the upper load transmission wall 26 is joined and the second load receiving wall 25 to which the lower load transmission wall 24 is joined are arranged to be flush with each other and face the front side of the vehicle.

[0037] In this embodiment, the connecting wall portion 28 is formed by continuously bending a plate-like wall portion extending substantially along the vehicle longitudinal direction in a crank-like shape in the vertical and horizontal directions, similar to the first open cross-sectional portion 21 and the second open cross-sectional portion 22. In this embodiment, the connecting wall portion 28 also has an open cross-sectional shape that is open in a direction intersecting the vehicle longitudinal direction.

[0038] As shown in FIG. 4 , the second open cross-sectional portion 22, the connecting wall portion 28, and the first open cross-sectional portion 21 of the load-receiving member 20 are formed into a crank-like cross-sectional shape that is continuous from top to bottom. More specifically, the above-mentioned portions (22, 28, 21) of the load-receiving member 20 are connected in the vertical direction of the vehicle by an inner opening 29 that opens in a generally U-shape on the inside in the vehicle width direction when viewed from the front of the vehicle, and an outer opening 30 that opens in a generally U-shape on the outside in the vehicle width direction when viewed from the front of the vehicle. These inner openings 29 and outer openings 30 are connected in multiple locations in the vertical direction of the vehicle. In other words, multiple generally S-shaped cross-sectional portions 31 formed by connecting the inner openings 29 and outer openings 30 are connected in the vertical direction of the vehicle.

[0039] As shown in FIG. 4 , the vehicle width directional inner walls 30wi of the outer openings 30 adjacent to each other in the vertical direction of the load receiving member 20 are arranged such that the lower inner wall 30wi is shifted more inward in the vehicle width direction than the upper inner wall 30wi when viewed from the vehicle front-rear direction. Similarly, the vehicle width directional outer walls 29wo of the inner openings 29 adjacent to each other in the vertical direction of the load receiving member 20 are arranged such that the lower outer wall 29wo is shifted more inward in the vehicle width direction than the upper outer wall 29wo when viewed from the vehicle front-rear direction. The surface of the load receiving member 20 facing outward in the vehicle width direction forms the inner surface of the front side of the front wheel house that accommodates the front wheels W. In this embodiment, the vehicle width directional outer wall 29wo of the inner openings 29 is shifted more inward in the vehicle width direction as it extends downward as described above, which makes it easy to prevent the front wheels W from interfering with the load receiving member 20 when the front wheels W are steered.

[0040] Furthermore, the vehicle width direction inner walls 30wi and the upper and lower corners c (ridges) thereof of the outer openings 30 adjacent to each other in the vertical direction of the load-receiving member 20 are inclined outward in the vehicle width direction from rear to front when viewed from above. However, the inclination angles of the vehicle width direction inner walls 30wi and the upper and lower corners c of the outer openings 30 (the angles at which they incline outward in the vehicle width direction from rear to front when viewed from above) are set to different angles for each of the outer openings 30 that are spaced apart in the vertical direction.

[0041] Figure 5 is a view of the load-receiving member 20 as seen from the arrow V in Figure 4. As shown in Figure 5, the load-receiving member 20 has an inner opening 29 and an outer opening 30, each of which is composed of two walls facing substantially horizontally and one wall facing substantially vertically. The inner opening 29 and outer opening 30, which are arranged above and below, share a single wall facing substantially horizontally. Hereinafter, the wall facing substantially vertically will be referred to as a first wall 33, and the wall facing substantially horizontally will be referred to as a second wall 34.

[0042] Here, the load-receiving member 20 can be considered as a plurality of substantially L-shaped curved wall elements, each consisting of a first wall 33 and a second wall 34, arranged in series. The first wall 33 and the second wall 34 constituting each curved wall element are provided with uneven portions that alternately protrude on one side and the other side in the direction perpendicular to the surface in the longitudinal direction of the vehicle. Hereinafter, the uneven portion formed on the first wall 33 will be referred to as a first uneven portion 35, and the uneven portion formed on the second wall 34 will be referred to as a second uneven portion 36. Note that, for convenience of illustration, the first uneven portion 35 and the second uneven portion 36 are omitted from FIG. 3 .

[0043] FIG. 6 is a longitudinal cross-sectional view of the load receiving member 20, showing a simplified schematic view of a portion of the load receiving member 20. FIG. 7 is a schematic side view of the load receiving member 20 corresponding to the view of arrow VII in FIG. 6 , and FIG. 8 is a schematic bottom view of the load receiving member 20 corresponding to the view of arrow VIII in FIG. 6 . FIG. 9 is a schematic view showing a cross section (a) of the load receiving member 20 taken along the first direction F and the third direction T, and a cross section (b) of the load receiving member 20 taken along the first direction F and the second direction S. Next, with reference to FIGS. 6 to 9 , the specific structure of the wall portion of the load receiving member 20, which mainly comprises a first wall 33 and a second wall 34, will be described. In the following description, the main input direction of the load to be absorbed is defined as the first direction F, one direction substantially perpendicular to (intersecting with) the first direction F is defined as the second direction S, and another direction substantially perpendicular to (intersecting with) the first direction F and the second direction S is defined as the third direction T.

[0044] The first wall 33 described above extends substantially along the first direction F and the second direction S, and the second wall 34 extends substantially along the first direction F and the third direction T. The first wall 33 and the second wall 34 form an open cross section that is open in a direction intersecting the first direction F.

[0045] As shown in FIG. 8 , the first uneven portion 35 of the first wall 33 described above is bent toward the first direction F so as to alternately protrude to one side and the other side in the third direction T when viewed from the second direction S. As shown in FIG. 7 , the second uneven portion 36 of the second wall 34 described above is bent toward the first direction F so as to alternately protrude to one side and the other side in the second direction S when viewed from the third direction T. That is, the first uneven portion 35 and the second uneven portion 36 are shaped so as to alternately protrude to one side and the other side in the plane-perpendicular direction toward the first direction F (the vehicle front-rear direction). Note that the "plane-perpendicular direction" refers to a direction substantially perpendicular to the outer surface of the first wall 33 for the first uneven portion 35, and a direction substantially perpendicular to the outer surface of the second wall 34 for the second uneven portion 36.

[0046] 8, the first uneven portion 35 of the first wall 33 has a first convex portion 37 that protrudes in a direction away from the second wall 34 and a first concave portion 38 that is recessed in a direction approaching the second direction S when viewed from the second direction S. As shown in FIG. 7, the second uneven portion 36 of the second wall 34 has a second convex portion 39 that protrudes in a direction away from the first wall 33 and a second concave portion 40 that is recessed in a direction approaching the first wall 33 when viewed from the third direction.

[0047] In the first wall 33, the most protruding portion of the first convex portion 37 and the most recessed portion of the first recess 38 are connected by a flat surface. As shown in Fig. 7 , the top t, which is the most protruding portion of the first convex portion 37, and the bottom b, which is the most recessed portion of the first recess 38, extend linearly along the second direction S. Similarly, in the second wall 34, the most protruding portion of the second convex portion 39 and the most recessed portion of the second recess 40 are connected by a flat surface. As shown in Fig. 8 , the top t of the second convex portion 39 and the bottom b of the second recess 40 extend linearly along the third direction T.

[0048] The first convex portion 37 on the first wall 33 and the second convex portion 39 on the second wall 34 are arranged at approximately the same position in the first direction F. Similarly, the first concave portion 38 on the first wall 33 and the second concave portion 40 on the second wall 34 are arranged at approximately the same position in the first direction F. Furthermore, at the corner c (ridge portion) where the first wall 33 and the second wall 34 are joined, as shown in FIG. 5 , convex-shaped portions 41 continuing from the first convex portion 37 and the second convex portion 39 and concave portions 42 continuing from the first concave portion 38 and the second concave portion 40 are arranged alternately along the first direction F.

[0049] The load-receiving member 20 has fracture inducing portions 44 at the most protruding portions of each first convex portion 37 of the first uneven portion 35 and at the most protruding portions of each second convex portion 39 of the second uneven portion 36. That is, the fracture inducing portions 44 are provided at a plurality of locations in the first direction of the first uneven portion 35 and the second uneven portion 36. The fracture inducing portions 44 have a smaller section modulus in the perpendicular direction than other portions. Specifically, the fracture inducing portions 44 provided in the first convex portion 37 are set to have a smaller section modulus in the third direction T than the first concave portion 38, and the fracture inducing portions 44 provided in the second convex portion 39 are set to have a smaller section modulus in the second direction S than the second concave portion 40. In the following, the portion of the first convex portion 37 with a small cross-sectional modulus in the third direction T may be referred to as the "first small cross-sectional modulus portion m1," and the portion of the second convex portion 39 with a small cross-sectional modulus in the second direction S may be referred to as the "second small cross-sectional modulus portion m2."

[0050] In this embodiment, the magnitude of the section modulus in the first uneven portion 35 and the second uneven portion 36 is changed by changing the thickness of the material in the target direction. Specifically, in the first uneven portion 35, as shown in FIG. 9A, the thickness t1 in the third direction T at the most protruding portion of the first convex portion 37 is set to be thinner (thinnest) than the thicknesses in the third direction T of the other portions. Also, in the second uneven portion 36, as shown in FIG. 9B, the thickness t1 in the second direction S at the most protruding portion of the second convex portion 39 is set to be thinner (thinnest) than the thicknesses in the second direction S of the other portions.

[0051] As shown in FIG. 9A , the first uneven portion 35 has a thickness t2 in the third direction T at the most recessed portion of the first recess 38 that is thicker (thickest) than the thicknesses in the third direction T of the remaining portions. Also, as shown in FIG. 9B , the second uneven portion 36 has a thickness t2 in the second direction S at the most recessed portion of the second recess 40 that is thicker (thickest) than the thicknesses in the second direction S of the remaining portions. Therefore, in the first uneven portion 35 and the second uneven portion 36, the most protruding portions of the convex portions (first convex portion 37, second convex portion 39) have the smallest section modulus, and the most recessed portions of the concave portions (first concave portion 38, second concave portion 40) have the largest section modulus. Therefore, in the first uneven portion 35 and the second uneven portion 36, the most protruding portions of the convex portions (first convex portion 37, second convex portion 39) have the lowest rigidity and strength. Therefore, when an impact load is applied, the most protruding portion of each convex portion (first convex portion 37, second convex portion 39) functions as the fracture inducing portion 44. Furthermore, the most recessed portion of each concave portion (first concave portion 38, second concave portion 40) has higher rigidity and strength than other portions, and therefore can smoothly transmit the input load and reaction force to the front and rear convex portions (first convex portion 37, second convex portion 39) when an impact load is applied. At the corner c between the first wall 33 and the second wall 34, the thickness of the top of the convex portion 41 is set to be the thinnest, and the thickness of the bottom of the concave portion 42 is set to be the thickest.

[0052] In this embodiment, the fracture inducing portions 44 (first small cross-sectional modulus portion m1, second small cross-sectional modulus portion m2) are provided at the most protruding portions of each of the first and second uneven portions 35, 36. However, the locations where the fracture inducing portions 44 (first small cross-sectional modulus portion m1, second small cross-sectional modulus portion m2) are provided are not limited to the most protruding portions of each of the first and second uneven portions 35, 36. The fracture inducing portions 44 (first small cross-sectional modulus portion m1, second small cross-sectional modulus portion m2) may be provided, for example, at portions of each of the first and second uneven portions 35, 36 that are not the most protruding portions of each of the first and second uneven portions 36, or at recesses (first recess 38, second recess 40). Furthermore, the means for reducing the cross-sectional modulus of the fracture inducing portions 44 is not limited to reducing the thickness. For example, it is also possible to provide a notch or a small hole in a portion of each of the first and second uneven portions 35, 36.

[0053] 9(b), the distance D1 in the first direction F between the most protruding portion of the first convex portion 37 and the most recessed portion of the first recess 38 in the first uneven portion 35 is set to be narrower than the dimension L1 in the second direction S at the most protruding portion of the first convex portion 37. Also, as shown in FIG. 9(a), the distance D2 in the first direction F between the most protruding portion of the second convex portion 39 and the most recessed portion of the second recess 40 in the second uneven portion 36 is set to be narrower than the dimension L2 in the third direction T at the most protruding portion of the second convex portion 39.

[0054] As shown in FIG. 9A , the opening angle α1 between two planes (two planes adjacent in the first direction F) sandwiching the apex of the first convex portion 37 of the first wall 33 (first concave-convex portion 35) is set to be an obtuse angle (90°<α1<180°). Similarly, the opening angle α2 between two planes (two planes adjacent in the first direction F) sandwiching the bottom of the first concave portion 38 of the first wall 33 (first concave-convex portion 35) is set to be an obtuse angle (90°<α2<180°). Furthermore, as shown in FIG. 9B , the opening angle α1 between two planes (two planes adjacent in the first direction F) sandwiching the apex of the second convex portion 39 of the second wall 34 (second concave-convex portion 36) is set to be an obtuse angle (90°<α1<180°). Similarly, the opening angle α2 between two planes (two planes adjacent in the first direction F) sandwiching the bottom of the second recess 40 of the second wall 34 (second uneven portion 36) is set to be an obtuse angle (90°<α2<180°). Note that the above openings α1 and α2 are preferably in the range of 120°<α1, α2<180°, and most preferably α1 and α2 are 150°.

[0055] Figure 10 is a cross-sectional view sequentially showing, in (a) to (c), the deformation behavior of the load-receiving member 20 when an impact load is applied. Note that Figure 10 only shows a portion of the first uneven portion 35 and the second uneven portion 36 of the load-receiving member 20. The deformation behavior of the load-receiving member 20 when an impact load is applied will be described below with reference to Figure 10.

[0056] 10( a), when an impact load F is input from the front to the front portion of the load-receiving member 20, the input load is first transmitted to the frontmost convex portions (first convex portion 37, second convex portion 39) of the first uneven portion 35 and the second uneven portion 36. At this time, stress acts on the fracture inducing portions 44 (first small section modulus portion m1, second small section modulus portion m2) at the apex of each convex portion (first convex portion 37, second convex portion 39), and each convex portion (first convex portion 37, second convex portion 39) bends (deforms) so as to be compressed in the fore-and-aft direction of the vehicle, and fracture begins at the fracture inducing portion 44 at the apex.

[0057] 10(b), the front side portions of the foremost convex portions (first convex portion 37, second convex portion 39) are crushed, and the crushed fragments are ejected outside the open cross section of the load-receiving member 20. If the impact load F continues to act on the front portion of the load-receiving member 20, the load is transmitted to the next convex portion (first convex portion 37, second convex portion 39) of the first uneven portion 35 and the second uneven portion 36. At this time, thick recesses (first recess 38, second recess 40) are disposed between the fractured remains of the foremost convex portion (first convex portion 37, second convex portion 39) and the next convex portion (first convex portion 37, second convex portion 39). Therefore, the load is transmitted efficiently from the fractured remains of the foremost convex portion (first convex portion 37, second convex portion 39) to the next convex portion (first convex portion 37, second convex portion 39). In addition, the load acting on the next convex portion (first convex portion 37, second convex portion 39) is received by a thicker concave portion (first concave portion 38, second concave portion 40) located rearward of that convex portion (first convex portion 37, second convex portion 39).

[0058] 10(c), when the load is concentrated on the top of the next convex portion (first convex portion 37, second convex portion 39), the next convex portion (first convex portion 37, second convex portion 39) bends (deforms) so as to be compressed in the fore-and-aft direction of the vehicle, and begins to break from the break induction portion 44 at the top. After this, the next convex portion (first convex portion 37, second convex portion 39) breaks and is ejected outside the open cross section of the load-receiving member 20.

[0059] Similarly, the fracture progresses from the top (fracture inducing portion 44) of each of the convex portions (first convex portion 37, second convex portion 39) toward the rear of the vehicle. As the deformation and fracture of the load-receiving member 20 progresses from the front to the rear in this manner, the impact load input during this time is absorbed. Furthermore, because the fracture of the load-receiving member 20 progresses from the front to the rear when absorbing the impact load, it is unlikely that any remaining crushed portions of the load-receiving member 20 will remain.

[0060] As described above, the load-receiving member 20 of this embodiment has a first wall 33 and a second wall 34 that form an open cross section, and these first wall 33 and second wall 34 constitute curved wall elements that form the main part of the load-receiving member 20. The first wall 33 and the second wall 34 each have a first uneven portion 35 and a second uneven portion 36. The first uneven portion 35 has a shape that, when viewed from the second direction S, alternately protrudes to one side and the other side in the third direction T toward the first direction F, and the second uneven portion 36 has a shape that, when viewed from the third direction T, alternately protrudes to one side and the other side in the second direction S toward the first direction F. The first uneven portion 35 and the second uneven portion 36 have fracture induction portions 44 provided at multiple locations in the first direction F. For this reason, in the load-receiving member 20 of this embodiment, when an impact load is input, the first uneven portion 35 and the second uneven portion 36 can be successively deformed and crushed at multiple locations starting from the fracture inducing portion 44. Therefore, when the load-receiving member 20 of this embodiment is used, it is possible to suppress residual crushing when an impact load is input, and to ensure a sufficient energy absorption stroke.

[0061] Furthermore, since the load-receiving member 20 of this embodiment has an open cross-sectional shape that is open in a direction intersecting the first direction F, fragments that are broken when an impact load is input can be smoothly discharged to the outside of the open cross-section. Therefore, when this configuration is adopted, this also contributes to further suppressing the remaining crushed portion of the load-receiving member.

[0062] When the load-receiving members 20 are coupled to the left and right front surfaces of the suspension support structure 15 so as to extend in the front and rear directions of the vehicle, as in this embodiment, the energy of the impact load input from the front of the vehicle can be efficiently absorbed by the front side of the suspension support structure 15. When the load-receiving members 20 of this embodiment are employed, there is no need to make the front-to-rear length of the load-receiving members 20 longer than necessary, which increases the degree of freedom in changing the design and specifications of the front of the vehicle.

[0063] Furthermore, in the load-receiving member 20 of this embodiment, the first convex portion 37 of the first uneven portion 35 and the second convex portion 39 of the second uneven portion 36 are arranged at approximately the same position in the first direction F, and the first concave portion 38 of the first uneven portion 35 and the second concave portion 40 of the second uneven portion 36 are also arranged at approximately the same position in the first direction F. Therefore, when an impact load is input, the input load is easily transmitted to the corresponding portions of the first uneven portion 35 and the second uneven portion 36 at the same time. Therefore, by arranging fracture inducing portions 44 in the corresponding portions of the first uneven portion 35 and the second uneven portion 36, the corresponding portions of the first uneven portion 35 and the second uneven portion 36 can be deformed and fractured at the same time. Therefore, when the load-receiving member 20 of this embodiment is adopted, the deformation and fracture of the load-receiving member 20 can proceed more smoothly.

[0064] Furthermore, in the load-receiving member 20 of this embodiment, the first convex portions 37 of the first uneven portion 35 have first small section modulus portions m1 having a smaller section modulus in the third direction T than the first concave portions 38, and the second convex portions 39 of the second uneven portion 36 have second small section modulus portions m2 having a smaller section modulus in the second direction S than the second concave portions 40. The first small section modulus portions m1 constitute the fracture inducing portions 44 in the first uneven portion 35, and the second small section modulus portions m2 constitute the fracture inducing portions 44 in the second uneven portion 36. Therefore, when an impact load is input in the first direction F, each of the convex portions (first convex portions 37, second convex portions 39) having a smaller section modulus can be used as a starting point to deform and fracture each of the uneven portions. Furthermore, when this configuration is adopted, by appropriately setting and adjusting the section modulus of the first convex portion 37 and the second convex portion 39, the deformation and crushing behavior of the load-receiving member 20 can be easily controlled without providing a thick portion such as a reinforcing rib.

[0065] Furthermore, in the load-receiving member 20 of this embodiment, the thickness t2 of the most recessed portion of the first recess 38 in the first uneven portion 35 is set to be thicker than the thickness of the first convex portion 37 (thicker than the thickness t1 of the first small cross-sectional modulus portion m1), and the thickness t2 of the most recessed portion of the second recess 40 in the second uneven portion 36 is set to be thicker than the thickness of the second convex portion 39 (thicker than the thickness t1 of the second small cross-sectional modulus portion m2). In this case, by changing the section modulus of each portion in each uneven portion (first uneven portion 35, second uneven portion 36) by setting the thickness, it is possible to set the first small cross-sectional modulus portion m1 or the second small cross-sectional modulus portion m2 in each convex portion (first convex portion 37, second convex portion 39), and to make the most recessed portion of each concave portion (first concave portion 38, second concave portion 40) less likely to deform (to increase the section modulus). Furthermore, in this configuration, by setting the section modulus of each convex portion small and the section modulus of the deepest portion of each concave portion large, when an impact load is input, the load is received by the concave portion adjacent to the convex portion to which the load is first input, making it possible to more reliably crush that convex portion. Furthermore, the concave portion, which is highly rigid and resistant to deformation, can smoothly transmit the load to the next convex portion. Therefore, when this configuration is adopted, it is possible to smoothly progress the crushing starting from the convex portion in the direction of the load input.

[0066] Furthermore, in the load-receiving member 20 of this embodiment, the most protruding portion of the first convex portion 37 of the first uneven portion 35 is the first small section modulus portion m1, and the most protruding portion of the second convex portion 39 of the second uneven portion 36 is the second small section modulus portion m2. Therefore, when an impact load is applied, deformation and crushing can begin from the most protruding portion of each convex portion. Therefore, when this configuration is adopted, adjacent convex portions can be crushed evenly, making it less likely that remaining pieces or fragments will remain.

[0067] Furthermore, in the load-receiving member 20 of this embodiment, the open cross section defined by the first wall 33 and the second wall 34 is formed by a cast part made of an aluminum alloy. This reduces the breaking strength compared to when the open cross section defined by the first wall 33 and the second wall 34 is formed from an iron-based metal, making it easier to fracture when an impact load is applied. This makes it less likely that the open cross section will remain crushed or leave fragments when an impact load is applied. Furthermore, in this configuration, because the open cross section defined by the first wall 33 and the second wall 34 is formed by casting, the section modulus (wall thickness) of each part can be more easily adjusted.

[0068] Furthermore, in the load-receiving member 20 of this embodiment, convex portions 41 continuing from the first convex portions 37 and the second convex portions 39 and concave portions 42 continuing from the first concave portions 38 and the second concave portions 40 are alternately arranged along the first direction F at the corners c (ridges) where the first wall 33 and the second wall 34 are connected. Therefore, the convex portions 41 and the concave portions 42 provided at the corners c function as reinforcing beads that restrict collapse between the first wall 33 and the second wall 34. Therefore, when this configuration is adopted, the strength and rigidity of the load-receiving member 20 during normal use can be increased.

[0069] Furthermore, in the load-receiving member 20 of this embodiment, as shown in FIG. 9 , the distance D1 in the first direction F between the most protruding portion of the first convex portion 37 of the first uneven portion 35 and the most recessed portion of the first recess 38 is set to be narrower than the dimension L1 in the second direction S at the most protruding portion of the first convex portion 37. Similarly, the distance D2 in the first direction F between the most protruding portion of the second convex portion 39 of the second uneven portion 36 and the most recessed portion of the second recess 40 is set to be narrower than the dimension L2 in the third direction T at the most protruding portion of the second convex portion 39. Therefore, when an impact load is applied, the load-receiving member 20 can be crushed into small pieces along the uneven portions (first uneven portion 35, second uneven portion 36). Therefore, when this configuration is adopted, the amount of energy absorbed by the deformation and crushing of the uneven portions (first uneven portion 35, second uneven portion 36) can be increased. In the case of existing technology that promotes the bellows-like collapse when an impact load is applied by providing a plurality of reinforcing ribs spaced apart in a first direction on a load-receiving member, increasing the number of flexions of the bellows when the load is applied increases the remaining crushing margin. In contrast, the load-receiving member 20 of this embodiment is crushed sequentially from the front side in the load input direction when an impact load is applied, so even if a structure is adopted in which deformation and crushing occur in small increments, the problem of an increase in the remaining crushing margin does not occur.

[0070] 9, in the load-receiving member 20 of this embodiment, the opening angles α1, α2 between the two flat surfaces adjacent in the first direction that form the first uneven portion 35 and the opening angles α1, α2 between the two flat surfaces adjacent in the first direction that form the second uneven portion 36 are both set to be obtuse angles. Therefore, by setting appropriate opening angles α1, α2, it is possible to suitably achieve both the transmission of the load in the first direction F at each uneven portion (first uneven portion 35, second uneven portion 36) when an impact load is input, and fracture starting from the fracture inducing portion 44.

[0071] In the above-described embodiment, the first uneven portion 35 and the second uneven portion 36 have a shape in which a plurality of flat surfaces are connected in the first direction F so as to form an obtuse angle, but the shapes of the first uneven portion and the second uneven portion are not limited to this. The shapes of the first uneven portion and the second uneven portion may be, for example, shapes like those of the various modifications shown in FIGS. 11 to 13 .

[0072] 11 is a cross-sectional view along the first direction of the uneven portion of the load-receiving member 120 of the first modified example. In this load-receiving member 120 of the first modified example, the convex portion 137 and the concave portion 138 of the uneven portion are formed by arc-shaped (curved) surfaces.

[0073] 12 is a cross-sectional view along the first direction of the uneven portion of a load receiving member 220 of the second modified example. In this load receiving member 220 of the second modified example, the convex portions 237 and the concave portions 238 of the uneven portion are formed in a trapezoidal shape.

[0074] 13 is a cross-sectional view along the first direction of the uneven portion of a load-receiving member 320 of the third modified example. In this load-receiving member 320 of the third modified example, the convex portion 337 and the concave portion 338 of the uneven portion are formed in a trapezoidal shape with a step portion 50 at the boundary between the convex portion 337 and the concave portion 338.

[0075] In each of these modified examples, fracture inducing portions with a small section modulus are provided at multiple locations on the uneven portion by adjusting the wall thickness, etc. The uneven shape provided on the load-receiving member controls the folding direction (fracture direction) when an impact load is input, so various shapes such as those in the modified examples above can be adopted. Deformation and fracture of the load-receiving member can be achieved by appropriately providing fracture inducing portions with a small section modulus.

[0076] The present invention is not limited to the above-described embodiment, and various design modifications are possible without departing from the spirit and scope of the present invention. For example, in the above-described embodiment, the load-receiving members 20, 120, 220, and 320 are disposed on the front surface of the damper housing 10 at the front of the vehicle, and are configured to receive impact loads from the front of the vehicle. However, the location of the load-receiving members and the direction in which the load is received are not limited to this. The load-receiving members may be disposed at locations other than the front of the vehicle, and the direction in which the load is received may be other directions, such as the vehicle width direction (e.g., a direction in which an impact load input from the side of the vehicle is received) or the vertical direction (e.g., a direction in which an impact load acting on the top surface of the front hood is received).

[0077] 20, 120, 220, 330... Load-receiving member 33... First wall 34... Second wall 35... First uneven portion 36... Second uneven portion 37... First convex portion 38... First concave portion 39... Second convex portion 40... Second concave portion 41... Convex portion 42... Concave portion 44... Fracture inducing portion c... Corner portion m1... First small section modulus portion m2... Second small section modulus portion

Claims

1. A load-receiving member for a vehicle, wherein the main input direction of a load to be absorbed is defined as a first direction, a direction intersecting the first direction as a second direction, and another direction intersecting the first and second directions as a third direction, the load-receiving member comprising: a first wall extending generally along the first and second directions; and a second wall extending generally along the first and third directions, the first and second walls forming an open cross section that is open in the direction intersecting the first direction, the first wall having a first uneven portion that, when viewed from the second direction, protrudes alternately on one side and the other side in the third direction toward the first direction, the second wall having a second uneven portion that, when viewed from the third direction, protrudes alternately on one side and the other side in the second direction toward the first direction, and fracture inducing portions are provided at multiple locations in the first direction of the first uneven portion and the second uneven portion.

2. The load-receiving member for a vehicle described in claim 1, characterized in that the first uneven portion of the first wall has, when viewed from the second direction, a first convex portion that protrudes in a direction away from the second wall and a first concave portion that is recessed in a direction approaching the second wall, and the second uneven portion of the second wall has, when viewed from the third direction, a second convex portion that protrudes in a direction away from the first wall and a second concave portion that is recessed in a direction approaching the first wall, and the first convex portion and the second convex portion, and the first concave portion and the second concave portion are each arranged at approximately the same position in the first direction.

3. A load-receiving member for a vehicle as set forth in claim 1 or 2, characterized in that the first uneven portion of the first wall, when viewed from the second direction, has a first convex portion that protrudes in a direction away from the second wall and a first concave portion that is recessed in a direction approaching the second wall; the second uneven portion of the second wall, when viewed from the third direction, has a second convex portion that protrudes in a direction away from the first wall and a second concave portion that is recessed in a direction approaching the first wall; the first convex portion has a first small cross-sectional modulus portion that has a smaller cross-sectional modulus in the third direction than the first concave portion; the second convex portion has a second small cross-sectional modulus portion that has a smaller cross-sectional modulus in the second direction than the second concave portion; the first small cross-sectional modulus portion constitutes the fracture inducing portion in the first uneven portion; and the second small cross-sectional modulus portion constitutes the fracture inducing portion in the second uneven portion.

4. A load-receiving member for a vehicle as described in claim 3, characterized in that the thickness of the most recessed portion of the first recess is set to be thicker than the thickness of the first protrusion, and the thickness of the most recessed portion of the second recess is set to be thicker than the thickness of the second protrusion.

5. A load-receiving member for a vehicle as described in claim 3 or 4, characterized in that the most protruding portion of the first convex portion is the first small cross-sectional modulus portion, and the most protruding portion of the second convex portion is the second small cross-sectional modulus portion.

6. A load-bearing member for a vehicle according to claim 1 or 2, characterized in that the open cross section formed by the first wall and the second wall is made of a cast part made of an aluminum alloy.

7. A load-receiving member for a vehicle as described in claim 2, characterized in that at the corner where the first wall and the second wall are connected, convex portions continuing from the first convex portion and the second convex portion and concave portions continuing from the first concave portion and the second concave portion are alternately arranged along the first direction.

8. A load-receiving member for a vehicle as described in claim 2, characterized in that the distance in the first direction between the most protruding portion of the first convexity and the most recessed portion of the first recess is set narrower than the dimension in the second direction at the most protruding portion of the first convexity, and the distance in the first direction between the most protruding portion of the second convexity and the most recessed portion of the second recess is set narrower than the dimension in the third direction at the most protruding portion of the second convexity.

9. A load-receiving member for a vehicle as described in claim 2, characterized in that the most protruding portion of the first convexity and the most recessed portion of the first recess of the first wall are connected by a flat surface, the most protruding portion of the second convexity and the most recessed portion of the second recess of the second wall are connected by a flat surface, and the opening angle between two adjacent flat surfaces of the first wall in the first direction and the opening angle between two adjacent flat surfaces of the second wall in the first direction are both set to form an obtuse angle.

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