Impact-absorbing structure

Abstract

To provide an impact-absorbing structure capable of reducing a load difference in a breaking load.SOLUTION: An arrangement position of a rib 26 of an upper stage part 18 and an arrangement position of a rib 30 of a lower stage part 20 in a front side member 16 are displaced from each other by half a wavelength in a longer direction (a load input direction) of the front side member 16. Therefore, arrangement positions of a chamber part 28 of the upper stage part 18 and a chamber part 32 of the lower stage part 20 are displaced from each other by half the wavelength in the load input direction. As compared to a case where breaking loads are generated substantially at the same timing in the load input direction in the upper stage part 18 and the lower stage part 20, a number of times impact energy is absorbed is increased. Accordingly, the breaking loads are reduced, and deceleration G can be reduced. Since generation of the breaking loads and free running occur alternately substantially at the same intervals, a load difference in each breaking load can be suppressed.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an impact absorption structure.

Background Art

[0002] Patent Document 1 discloses a technique related to an energy absorption structure in which left and right wheel houses and a crush zone adjacent to the wheel houses are integrally formed by die casting. In this prior art, a plurality of rooms partitioned by ribs are provided in the crushable zone, and impact energy is absorbed by crushing these rooms. In addition to this Patent Document 1, a structure similar to that of Patent Document 1 is also disclosed in the crush rail described in Patent Document 2.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In these prior arts, when a so-called crushable zone is sequentially crushed from the first chamber along the input direction of an impact load due to the input of the impact load, a large breaking load is generated when the first chamber is crushed, and impact energy is absorbed in the process. After that, the impact load is transmitted to the second chamber, but until the impact load is transmitted to the second chamber, it will run idle at a low breaking load. When the impact load is transmitted to the second chamber, the second chamber is crushed, and a large breaking load is generated when the second chamber is crushed. Next, the impact load is transmitted to the third chamber, but until the impact load is transmitted to the third chamber, it will run idle at a low breaking load, and a large breaking load is generated when the third chamber is crushed, and crushing and idling are repeated in this way. That is, the load difference (the difference between valleys) in the breaking load becomes large.

[0005] In view of the above facts, an object of the present invention is to obtain an impact absorption structure capable of reducing the load difference in the breaking load.

Means for Solving the Problem

[0006] The impact absorption structure according to the present invention described in claim 1 is formed by a mold and includes an impact absorption portion for a vehicle arranged along the input direction of an impact load. The impact absorption portion is arranged along a direction intersecting the load input direction, which is the input direction of the impact load, and a plurality of column portions are respectively provided with open portions opened in the arranged direction and a direction intersecting the load input direction. The open portion is partitioned into a plurality of chamber portions along the load input direction, and a plurality of ribs in which at least some of the adjacent column portions are displaced in the arrangement position along the load input direction are included.

[0007] The impact absorption structure according to the present invention described in claim 1 includes an impact absorption portion for a vehicle formed by a mold. The impact absorption portion is arranged along the input direction of the impact load and is composed of a plurality of column portions and a plurality of ribs.

[0008] A plurality of column portions are arranged in a plurality along a direction intersecting with the load input direction which is the input direction of the impact load. For example, when the load input direction is a direction along the longitudinal direction of the vehicle, the plurality of column portions are arranged along the vehicle width direction and the vehicle vertical direction. Further, each of the plurality of column portions is provided with an open portion that is open in a direction intersecting with the direction in which the plurality of column portions are arranged and the load input direction.

[0009] On the other hand, the plurality of ribs are arranged along the load input direction within the open portion provided in the column portion, and the open portion is partitioned into a plurality of room portions by the plurality of ribs. Further, at least a part of the plurality of ribs is formed such that the arrangement positions thereof are shifted along the load input direction between adjacent column portions.

[0010] Thus, in the present invention, in the impact absorbing portion, by providing a plurality of room portions along the load input direction, when an impact load is input to the impact absorbing portion, a breaking load is generated for each number of the room portions, and impact energy is absorbed in the process.

[0011] Here, by increasing the size of each room portion, the breaking load can be increased and the absorption of impact energy can be increased. However, in this case, the deceleration G (inertial force in the load input direction) increases and the free-running stroke also becomes longer. Further, as a comparative example, for example, when the arrangement positions of the ribs are synchronized along the load input direction between a plurality of adjacent column portions along a direction intersecting with the load input direction, the arrangement positions of the room portions are synchronized along the load input direction between the adjacent column portions.

[0012] Therefore, when an impact load is input to the impact absorbing portion, in the impact absorbing portion, a breaking load is generated at substantially the same timing in the load input direction between adjacent column portions along a direction intersecting with the load input direction. This breaking load is larger than that when there is one column portion when there are two column portions, and thus the deceleration G becomes larger accordingly.

[0013] In contrast, in the present invention, the shock absorption part is configured to include a plurality of column parts arranged along a direction intersecting the load input direction, and at least a part of a plurality of ribs formed in the open parts provided in each column part are arranged at positions shifted along the load input direction between adjacent column parts.

[0014] Thus, in the present invention, when the arrangement positions of the ribs are shifted along the load input direction between adjacent column parts along a direction intersecting the load input direction, the arrangement positions of the room parts are shifted along the load input direction between adjacent column parts. Therefore, in the present invention, when an impact load is input to the shock absorption part, in the shock absorption part, the breaking loads are generated at different timings in the load input direction between adjacent column parts.

[0015] For this reason, in the present invention, compared with the case where the breaking loads are generated at substantially the same timing in the load input direction between adjacent column parts, the number of times the impact energy is absorbed increases, and accordingly the breaking load becomes smaller, and it becomes possible to reduce the deceleration G. Further, in the present invention, since the arrangement positions of the ribs are shifted between adjacent column parts, it becomes possible to reduce the breaking load compared with the case where the arrangement positions of the ribs are synchronized, and it becomes possible to reduce the load difference in the so-called breaking load.

[0016] The shock absorption structure according to the present invention described in claim 2 is the shock absorption structure according to the present invention described in claim 1, wherein the ribs are arranged at positions shifted along the load input direction between the column parts at least on the upstream side in the load input direction in the shock absorption part.

[0017] In the shock absorption structure according to the present invention described in claim 2, since the ribs are arranged at positions shifted along the load input direction between the column parts at least on the upstream side in the load input direction in the shock absorption part, it becomes possible to reduce the load difference in the breaking load at least on the upstream side in the load input direction in the shock absorption part.

[0018] The shock absorption structure according to the present invention described in claim 3 is the shock absorption structure according to the present invention described in claim 1, wherein the room portion is formed such that the upstream side in the load input direction in the shock absorption portion is wider in the load input direction than the downstream side.

[0019] In the shock absorption structure according to the present invention described in claim 3, since the room portion is formed such that the upstream side in the load input direction in the shock absorption portion is wider in the load input direction than the downstream side, it is possible to make the breaking load larger on the upstream side in the load input direction than on the downstream side. That is, in the present invention, at the time of input of the impact load, it is possible to increase the absorption of the impact energy on the upstream side in the load input direction in the shock absorption portion more than on the downstream side.

[0020] The shock absorption structure according to the present invention described in claim 4 is the shock absorption structure according to the present invention described in claim 2, wherein the shock absorption portion is provided by a deviation in the arrangement position of the ribs generated along the load input direction between the column portions on the upstream side in the load input direction in the shock absorption portion, and includes a small room portion formed with a size smaller than a preset size of the room portion, and a first fragile portion provided along a direction intersecting the load input direction in the small room portion and serving as a starting point of deformation when the impact load is input.

[0021] In the shock absorption structure according to the present invention described in claim 4, the shock absorption portion further includes a small room portion and a first fragile portion. The small room portion is provided on the upstream side in the load input direction in the shock absorption portion and is formed with a size smaller than a preset size of the room portion due to a deviation in the arrangement position of the ribs generated along the load input direction between the column portions. Thereby, in the present invention, it is possible to align the positions on the end faces of the upstream portions in the load input direction between the column portions, and at the time of input of the impact load, it is possible to transmit the impact load substantially evenly among the plurality of column portions constituting the shock absorption member.

[0022] On the one hand, the first vulnerable part is provided along a direction intersecting the load input direction in the small room part. For example, it has lower rigidity than other parts and serves as a starting point for deformation when an impact load is input. The small room part is less likely to undergo buckling deformation because its dimension along the load input direction is shorter compared to other room parts outside the small room part. Therefore, in the present invention, by providing the first vulnerable part in the small room part, the deformation of the small room part is promoted starting from the first vulnerable part, the remaining crushing in the small room part is suppressed, and it is possible to suppress a decrease in the absorption efficiency of impact energy due to the remaining crushing.

[0023] The impact absorption structure according to the present invention described in claim 5 is the impact absorption structure according to the present invention described in claim 1, wherein on the inner surface side of the room part, a second vulnerable part is provided along a direction intersecting the load input direction and serving as a starting point for deformation when the impact load is input.

[0024] In the impact absorption structure according to the present invention described in claim 5, a second vulnerable part is provided on the inner surface side of the room part. This second vulnerable part is formed along a direction intersecting the load input direction and serves as a starting point for deformation when the impact load is input. That is, in the present invention, it is possible to stabilize the failure mode by deforming the room part starting from the second vulnerable part.

[0025] The impact absorption structure according to the present invention described in claim 6 is the impact absorption structure according to the present invention described in claim 5, wherein the first vulnerable part is formed to be more easily deformed than the second vulnerable part.

[0026] In the impact absorption structure according to the present invention described in claim 6, the first vulnerable part is formed to be more easily deformed than the second vulnerable part, and it is possible to effectively suppress the remaining crushing in the small room part.

[0027] The shock absorption structure according to the present invention described in claim 7 is the shock absorption structure according to the present invention described in claim 1, wherein on the outer surface side of the shock absorption portion, at a position corresponding to the rib, a third vulnerable portion that serves as a starting point of deformation when the shock load is input is provided along a direction intersecting the load input direction.

[0028] In the shock absorption structure according to the present invention described in claim 7, a third vulnerable portion is provided on the outer surface side of the shock absorption portion. This third vulnerable portion is provided at a position corresponding to the rib and is formed so as to serve as a starting point of deformation when the shock load is input. Since the rib divides the room portion, by providing the third vulnerable portion at a position corresponding to the rib, it is possible to prevent deformation from propagating between adjacent room portions along the load input direction.

[0029] Thereby, in the present invention, it is possible to suppress the destruction of adjacent room portions along the load input direction following the destroyed room portion, and it is possible to stabilize the destruction mode in each room portion.

[0030] The shock absorption structure according to the present invention described in claim 8 is the shock absorption structure according to the present invention described in claim 1, wherein two rows of the column portions are provided, and the second rib formed in the other column portion is shifted by 1 / 2 wavelength with respect to the first rib formed in one column portion.

[0031] In the shock absorption structure according to the present invention described in claim 8, in the shock absorption portion, two rows of column portions are provided. In the present invention, by shifting the second rib formed in the other column portion by 1 / 2 wavelength with respect to the first rib formed in one column portion, the generation and idling of the breaking load occurring in one column portion and the generation and idling of the breaking load occurring in the other column portion occur alternately at substantially the same interval with a 1 / 2 wavelength shift in timing. Therefore, for example, compared with the case where the second rib is shifted by 1 / 3 wavelength with respect to the first rib, in the present invention, it is possible to further suppress the load difference in the breaking load because the generation and idling of the breaking load occur alternately at substantially the same interval.

[0032] The shock absorption structure according to the present invention described in claim 9 is the shock absorption structure according to the present invention described in claim 5 and claim 7, wherein the shock absorption part includes an upper wall part extending along the load input direction, a lower wall part extending along the load input direction and arranged on the opposite side of the upper wall part, and a side wall part extending along the load input direction and connecting one end of the upper wall part and one end of the lower wall part. The third weak part is provided on the upper wall part and the lower wall part. On the side wall part, a fourth weak part is formed along a direction intersecting the load input direction between a position corresponding to the second weak part along the load input direction and the third weak part, and the fourth weak part serves as a starting point of deformation when the shock load is input.

[0033] In the shock absorption structure according to the present invention described in claim 9, the shock absorption part is composed of an upper wall part, a lower wall part and a side wall part. The upper wall part and the lower wall part extend along the load input direction, and one end of the upper wall part and one end of the lower wall part are connected by the side wall part. Here, the third weak part is provided on the upper wall part and the lower wall part, and the fourth weak part is provided on the side wall part. This fourth weak part is provided between a position corresponding to the second weak part along the load input direction and the third weak part, is formed along a direction intersecting the load input direction, and is formed to serve as a starting point of deformation when the shock load is input.

[0034] As described above, by providing the third weak part, it becomes possible to prevent deformation from propagating between adjacent room parts by the rib. In the present invention, further, by providing the fourth weak part on the side wall part of the shock absorption part, it becomes possible to deform the room part starting from the fourth weak part between the second weak part and the third weak part and suppress the remaining crush around the rib.

[0035] The shock absorption structure according to the present invention described in claim 10 is the shock absorption structure according to the present invention described in claim 1, wherein the shock absorption part is formed by casting.

[0036] In the shock absorption structure according to the present invention described in claim 10, since the shock absorption part is formed by casting, for example, compared with forming by extrusion molding, the degree of freedom in design is high in the shape of the shock absorption part, and the manufacturing efficiency is improved.

[0037] The shock absorption structure according to the present invention described in claim 11 is the shock absorption structure according to the present invention described in claim 1, wherein the shock absorption part is a side member arranged along the vehicle longitudinal direction at the end in the vehicle width direction, and the side member is integrally formed by casting with a wheel house in which a wheel is arranged.

[0038] In the shock absorption structure according to the present invention described in claim 11, in the shock absorption structure according to the present invention described in claim 1, the shock absorption part is a side member, and the side member and the wheel house are integrally formed by casting. Thereby, in the present invention, a fastening tool for fastening the side member and the wheel house becomes unnecessary, and the number of parts can be reduced.

[0039] The shock absorption structure according to the present invention described in claim 12 is the shock absorption structure according to the present invention described in claim 1, wherein the shock absorption part is left and right side members arranged along the vehicle longitudinal direction at both ends in the vehicle width direction, and the side members are integrally formed by casting with wheel houses in which left and right wheels are arranged and a cross member connecting the left and right wheel houses.

[0040] In the shock absorption structure according to the present invention described in claim 12, the shock absorption part is left and right side members, and the left and right side members, the left and right wheel houses, and a cross member connecting the left and right wheel houses are integrally formed by casting. Thereby, in the present invention, a fastening tool for fastening the side member and the wheel house and the left and right wheel houses and the cross member becomes unnecessary, and the number of parts can be further reduced.

Advantages of the Invention

[0041] As described above, the shock absorption structure according to the present invention can reduce the load difference at the breaking load.

Brief Description of the Drawings

[0042]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0043] Hereinafter, an impact absorption structure according to an embodiment of the present invention will be described with reference to the drawings. In each figure, the arrow FR appropriately shown indicates the front side in the vehicle longitudinal direction, and the arrow UP indicates the upper side in the vehicle vertical direction. The arrow LH indicates the left side in the vehicle width direction, and in this embodiment, it indicates the outer side in the vehicle width direction. Hereinafter, when simply describing the front-rear, up-down, and left-right directions, unless otherwise specified, it shall indicate the front-rear in the vehicle longitudinal direction, the up-down in the vehicle vertical direction, and the left-right in the vehicle left-right direction (vehicle width direction).

[0044] (Configuration of Impact Absorption Structure) First, the configuration of the impact absorption structure according to the present embodiment will be described.

[0045] FIG. 1 shows an overall vehicle view showing the skeleton of the vehicle 10. For example, this vehicle 10 is an electric vehicle, a fuel cell vehicle, etc. that runs on power generated by a power unit (not shown). As shown in FIG. 1, the impact absorption part 27 to which the impact absorption structure 11 according to the present embodiment is applied constitutes at least a part of the front side member 16. The front side member 16 is a skeletal member on the side of the vehicle 10, and in this embodiment, it is formed by casting using an aluminum alloy, a magnesium alloy, etc. as materials.

[0046] The front side member 16 is disposed on both the left and right sides in the vehicle width direction at the front part of the vehicle, and extends along the vehicle longitudinal direction respectively. And the power unit is disposed between the left and right front side members 16. Further, in front of the left and right front side members 16, crush boxes 12 capable of absorbing impact energy extend along the vehicle longitudinal direction respectively, and a front bumper 13 extends along the vehicle width direction at the front ends of the left and right crush boxes 12.

[0047] Here, the front bumper 13 and the crash box 12 are described as separate components, but they may be integrated. In this case, when they are integrated, the shock absorption structure 11 in the present embodiment may be applied to the so-called crash box 12 side, or may be applied to both the crash box 12 side and the front side member 16 side.

[0048] On the other hand, wheel houses 14 in which wheels (not shown) are arranged are respectively provided on the rear sides of the left and right front side members 16, and the right wheel house 14 and the left wheel house 14 are connected by a cross member 15. In the present embodiment, the left and right front side members 16, the left and right wheel houses 14, and the cross member 15 are integrally formed by casting.

[0049] An apron upper member 17 is arranged outside the front side member 16 in the vehicle width direction and above in the vehicle vertical direction. The apron upper member 17 is a skeletal member that constitutes the upper side skeleton of the vehicle body front part 19, extends in the vehicle front-rear direction along the front side member 16, and the rear end part of the apron upper member 17 is coupled to the front pillar 21. Further, a suspension tower 23 is integrally formed on the apron upper member 17. And a rocker 25 that extends along the vehicle front-rear direction and constitutes the skeleton of the vehicle side part is provided on the rear side in the vehicle front-rear direction of the wheel house 14.

[0050] Here, the shock absorption part 27 to which the shock absorption structure 11 is applied will be described. In the present embodiment, the front side member 16 is constituted by the shock absorption part 27. Therefore, in the following description, the shock absorption part 27 will be described by referring to it as the front side member 16.

[0051] As shown in FIG. 2, in the present embodiment, the front side member 16 extends along the vehicle longitudinal direction (the input direction of the impact load (hereinafter referred to as the "load input direction")) as described above. The front side member 16 includes an upper wall portion 16A, a lower wall portion 16B, and an inner wall portion 16C disposed inside in the vehicle width direction (a direction intersecting the load input direction) and connecting one end in the vehicle width direction of the upper wall portion 16A and one end in the vehicle width direction of the lower wall portion 16B. Although not shown, the inner wall portion 16C may be set to connect the center in the vehicle width direction of the upper wall portion 16A and the center in the vehicle width direction of the lower wall portion 16B.

[0052] Further, in the present embodiment, a partition wall 16D is provided at a substantially central portion in the vehicle vertical direction of the front side member 16, and the front side member 16 is composed of two upper and lower rows of an upper stage portion (row portion) 18 and a lower stage portion (row portion) 20 along the vehicle vertical direction (a direction intersecting the load input direction). The upper stage portion 18 and the lower stage portion 20 are formed to have substantially the same size.

[0053] The upper stage portion 18 includes an upper wall portion 18A, a lower wall portion 18B, and an inner wall portion 18C, and the lower stage portion 20 includes an upper wall portion 20A, a lower wall portion 20B, and an inner wall portion 20C. The upper wall portion 18A of the upper stage portion 18 constitutes at least a part of the upper wall portion 16A of the front side member 16, and the lower wall portion 20B of the lower stage portion 20 constitutes at least a part of the lower wall portion 16B of the front side member 16. And the inner wall portion 18C of the upper stage portion 18 and the inner wall portion 20C of the lower stage portion 20 constitute at least a part of the inner wall portion 16C of the front side member 16.

[0054] Also, the lower wall portion 18B of the upper stage portion 18 and the upper wall portion 20A of the lower stage portion 20 share the same wall portion (partition wall 16D). For convenience of explanation, in the description of the front side member 16 side, it is described as the partition wall 16D, in the description of the upper stage portion 18 side, it is described as the lower wall portion 18B, and in the description of the lower stage portion 20 side, it is described as the upper wall portion 20A, respectively.

[0055] In the upper part 18 and the lower part 20 of the front side member 16, there are respectively provided open portions 22, 24 having a substantially U-shaped cross-sectional shape cut along the vehicle width direction (a direction intersecting the load input direction) with the outer side in the vehicle width direction being open.

[0056] In the open portion 22 of the upper part 18, a plurality of ribs 26 having notches 26A formed in a substantially U-shaped shape with the outer side in the vehicle width direction being open are provided along the vehicle longitudinal direction (load input direction), and the open portion 22 is partitioned into a plurality of room portions 28 by the ribs 26. Further, in the open portion 24 of the lower part 20, similarly to the ribs 26, a plurality of ribs 30 having notches 30A formed in a substantially U-shaped shape with the outer side in the vehicle width direction being open are provided along the vehicle longitudinal direction, and the open portion 24 is partitioned into a plurality of room portions 32 by the ribs 30.

[0057] Note that the shapes of the notches 26A and 30A are not limited to a substantially U-shaped shape. Further, in the present embodiment, as described above, since the front side member 16 is formed by casting, draft angles are formed on the ribs 26 and 30, and the breadths of the notches 26A and 30A become wider toward the open ends 16G.

[0058] Here, as shown in FIG. 4, in the present embodiment, the ribs 26 of the upper part 18 and the ribs 30 of the lower part 20 of the front side member 16 are displaced in the arrangement positions along the longitudinal direction (vehicle longitudinal direction), and the ribs 26 and the ribs 30 are displaced, for example, by 1 / 2 wavelength. For this reason, the sizes of the room portions 28 and the room portions 32 arranged vertically are made to be substantially the same size.

[0059] Note that, as shown in FIG. 5, the room portions 28 and 32 may be formed such that the front end side of the front side member 16 (the upstream side in the load input direction in the shock absorbing portion) is wider than the rear end portion (the downstream side) in the load input direction. For example, in the dimension X in the vehicle front-rear direction in the room portion 32, it is set such that X1>X5. Also, X1≒X2≒X3 is set for the portions other than the rear portion side of the front side member 16, and in the rear portion side of the front side member 16, it may be set such that X3>X4>X5. However, it is not limited to this, and the size of the room portion along the vehicle front-rear direction may be adjusted between the front portion side and the rear portion side of the front side member 16.

[0060] Also, as shown in FIGS. 2 and 4, since the rib 26 and the rib 30 are shifted by 1 / 2 wavelength along the longitudinal direction of the front side member 16, a small room portion 34 having a size of about 1 / 2 of the room portion 28 is provided at the front end portion of the upper stage portion 18. Thereby, the front end surfaces 16E of the upper stage portion 18 and the lower stage portion 20 are adjusted to be substantially flush.

[0061] Note that, in the present embodiment, a small room portion 38 having a size of about 1 / 2 of the room portion 32 is also provided at the rear end portion of the lower stage portion 20 in the same manner as the front end portion, and the rear end surfaces 16F of the upper stage portion 18 and the lower stage portion 20 are formed to be substantially flush. However, in relation to the wheel house 14 (see FIG. 1), it is not always necessary for the rear end surfaces 16F of the upper stage portion 18 and the lower stage portion 20 to be flush.

[0062] Further, on the upper wall portion 34A of the small room portion 34, a convex portion (first vulnerable portion) 36 formed to be curved in an arc shape upward along the vehicle front-rear direction is provided along the vehicle width direction, and when an impact load is input to the front side member 16 (along the vehicle front-rear direction), the convex portion 36 serves as a starting point of deformation.

[0063] On the outer surface side of the upper wall portion 18A (the upper wall portion 16A of the front side member 16) of the upper stage portion 18, at a position corresponding to the rib 26, a concave bead (third vulnerable portion) 40 having an arcuate cross-sectional shape cut along the width direction of the recess in the plate thickness direction of the upper wall portion 18A is formed along the vehicle width direction (a direction intersecting the load input direction). Further, on the outer surface side of the lower wall portion 20B (the lower wall portion 16B of the front side member 16) of the lower stage portion 20, at a position corresponding to the rib 30, a concave bead 40 recessed in the plate thickness direction of the lower wall portion 20B is formed along the vehicle width direction.

[0064] In this way, when the concave bead 40 is formed, compared with the case where the concave bead 40 is not formed, the plate thickness of the upper wall portion 18A and the lower wall portion 20B becomes thinner, and the rigidity is correspondingly lower and more vulnerable. Therefore, when an impact load is input to the front side member 16, the concave bead 40 serves as a starting point for deformation.

[0065] Also, at substantially the center in the vehicle front-rear direction (load input direction) of each room portion 28 of the upper stage portion 18, on the inner surface side of the upper wall portion 18A, a concave bead (second vulnerable portion) 42 having an arcuate cross-sectional shape cut along the width direction of the recess in the plate thickness direction of the upper wall portion 18A is formed along the vehicle width direction (a direction intersecting the load input direction).

[0066] Furthermore, at substantially the center in the vehicle front-rear direction of each room portion 28 of the upper stage portion 18, on the inner surface side of the inner wall portion 18C, a concave bead (second vulnerable portion) 44 having an arcuate cross-sectional shape cut along the width direction of the recess in the plate thickness direction of the inner wall portion 18C is formed along the vehicle vertical direction (a direction intersecting the load input direction). Note that the concave bead 42 and the concave bead 44 are formed continuously.

[0067] Thus, at the portions where the concave beads 42 and 44 are formed, the plate thicknesses of the upper wall portion 18A and the inner wall portion 18C are thinner compared to the portions where the concave beads 42 and 44 are not formed, and accordingly, the rigidity is lower and they are vulnerable. Therefore, when an impact load is applied to the front side member 16, the concave beads 42 and 44 serve as the starting points of deformation.

[0068] Further, FIG. 6 shows a cross-sectional view taken along the line A-A' shown in FIG. 2. As shown in FIG. 6, on the inner wall portion 18C of the upper stage portion 18, between the concave bead 44 and the rib 26, a bead portion (fourth vulnerable portion) 46 that is arcuately curved outward in the vehicle width direction (arrow LH) along the vehicle longitudinal direction is provided along the vehicle vertical direction. Since the bead portion 46 protrudes outward in the vehicle width direction on the inner surface side of the inner wall portion 18C, as shown in FIG. 3, it is recessed outward in the vehicle width direction on the outer surface side of the inner wall portion 18C, and when an impact load is applied to the front side member 16, it serves as the starting point of deformation.

[0069] On the other hand, as shown in FIGS. 2 and 4, at substantially the central portions in the vehicle longitudinal direction of each room portion 32 of the lower stage portion 20, similar to the upper stage portion 18, on the inner surface side of the inner wall portion 20C, concave beads (second vulnerable portions) 48 that are recessed along the plate thickness direction of the inner wall portion 20C are respectively formed along the vehicle vertical direction. Further, at substantially the central portions in the vehicle longitudinal direction of each room portion 32 of the lower stage portion 20, on the inner surface side of the lower wall portion 20B, concave beads (second vulnerable portions) 50 that are recessed along the plate thickness direction of the lower wall portion 20B are respectively formed along the vehicle width direction. Note that the concave bead 48 and the concave bead 50 are continuously formed.

[0070] Thus, at the portions where the concave beads 48 and 50 are formed, similar to the upper stage portion 18, the plate thicknesses of the inner wall portion 20C and the lower wall portion 20B are thinner compared to the portions where the concave beads 48 and 50 are not formed, and accordingly, the rigidity is lower and they are vulnerable. Therefore, when an impact load is applied to the front side member 16, the concave beads 48 and 50 serve as the starting points of deformation.

[0071] Further, as shown in FIG. 6, on the inner wall portion 20C of the lower stage portion 20, between the concave bead 48 and the rib 30, a bead portion (fourth vulnerable portion) 52 formed to be arcuately curved outward in the vehicle width direction along the vehicle front-rear direction is provided along the vehicle vertical direction. Similar to the bead portion 46, since the bead portion 52 protrudes outward in the vehicle width direction on the inner surface side of the inner wall portion 20C, as shown in FIG. 3, it is recessed outward in the vehicle width direction on the outer surface side of the inner wall portion 20C and serves as a starting point of deformation when an impact load is input to the front side member 16.

[0072] On the other hand, the inner wall portion 16C of the front side member 16 is configured to include the inner wall portion 18C of the upper stage portion 18 and the inner wall portion 20C of the lower stage portion 20. Between the inner wall portion 18C of the upper stage portion 18 and the inner wall portion 20C of the lower stage portion 20, a substantially rectangular rib 54 protruding inward in the vehicle width direction is provided on the extension line of the partition wall 16D (see FIG. 2).

[0073] (Function and Effect of Impact Absorbing Structure) Next, the function and effect of the impact absorbing structure according to the present embodiment will be described.

[0074] As shown in FIG. 2, in the present embodiment, the front side member 16 as an impact absorbing portion formed by casting in a mold extends along the vehicle front-rear direction (longitudinal direction, load input direction) and includes an upper stage portion 18, a lower stage portion 20 as a plurality of column portions, and a plurality of ribs 26, 30. The upper stage portion 18 and the lower stage portion 20 are arranged vertically in the vehicle vertical direction, and a plurality of ribs 26, 30 are respectively arranged along the vehicle front-rear direction inside the upper stage portion 18 and the lower stage portion 20 (open portions 22, 24). The upper stage portion 18 and the lower stage portion 20 are partitioned into a plurality of room portions 28, 32 by the ribs 26, 30.

[0075] Thus, in the present embodiment, since a plurality of room portions 28 and 32 are provided along the vehicle longitudinal direction within the upper portion 18 and the lower portion 20, when an impact load is input to the front side member 16 (along the vehicle longitudinal direction), fracture loads are generated by the number of the room portions 28 and 32, and impact energy is absorbed in the process.

[0076] Here, in the present embodiment, the arrangement positions of the rib 26 and the rib 30 are shifted by 1 / 2 wavelength along the longitudinal direction (load input direction) of the front side member 16.

[0077] As a comparative example, for instance, although not shown in the drawings, when the arrangement positions of the rib 26 in the upper portion 18 and the rib 30 in the lower portion 20 of the front side member 16 are synchronized, the arrangement positions of the room portion 28 in the upper portion 18 and the room portion 32 in the lower portion 20 will be synchronized. For this reason, when an impact load is input to the front side member 16, fracture loads will be generated in the front side member 16 at substantially the same timing in the load input direction in the upper portion 18 and the lower portion 20, and accordingly, the deceleration G will increase. Also, in this case, the coasting timing in the upper portion 18 and the lower portion 20 will also be substantially the same.

[0078] On the other hand, in the present embodiment, as described above, the arrangement position of the rib 26 in the upper portion 18 and the arrangement position of the rib 30 in the lower portion 20 of the front side member 16 are shifted by 1 / 2 wavelength along the longitudinal direction (load input direction) of the front side member 16. For this reason, the arrangement positions of the room portion 28 in the upper portion 18 and the room portion 32 in the lower portion 20 will be shifted by 1 / 2 wavelength along the load input direction.

[0079] Therefore, in the present embodiment, compared with the case where fracture loads are generated at substantially the same timing in the load input direction in the upper portion 18 and the lower portion 20, in the present embodiment, the number of times of absorbing impact energy increases, the fracture load becomes smaller accordingly, and it becomes possible to reduce the deceleration G.

[0080] Further, in the present embodiment, when an impact load is input to the front side member 16, the generation and idling of the breaking load occurring in the upper part 18 and the generation and idling of the breaking load occurring in the lower part 20 will occur alternately at substantially the same intervals with a timing shift of 1 / 2 wavelength.

[0081] Therefore, for example, as a comparative example, compared with the case where the arrangement position of the rib 30 is shifted by 1 / 3 wavelength with respect to the rib 26, in the present embodiment, since the generation and idling of the breaking load occur alternately at substantially the same intervals, it is possible to further suppress the load difference in the breaking load.

[0082] Here, FIG. 7 shows, in a diagram, the relationship between the breaking load (kN) and the stroke (mm) when an impact load is input to the shock absorption part by CAE (COMPUTER AIDED ENGINEERING) analysis.

[0083] The result of the shock absorption part 27 (see FIG. 2) in the present embodiment is shown by a solid line, and the result of the shock absorption part in the comparative example is shown by a broken line. In the present embodiment, as shown by the arrow A in FIG. 7, it can be seen that the first occurring breaking load when an impact load is input to the shock absorption part 27 is reduced compared with the comparative example.

[0084] Further, in the present embodiment, as described above, since the generation and idling of the breaking load occurring in the upper part 18 (see FIG. 4) of the front side member 16 and the generation and idling of the breaking load occurring in the lower part 20 (see FIG. 4) occur alternately at substantially the same intervals with a timing shift of 1 / 2 wavelength, as shown by the arrow B, it is possible to generate a breaking load in the other row part during the idling of one row part side. That is, in the present embodiment, it is possible to increase the so-called valley load. Note that the comparative example is in the idling state. Therefore, in the present embodiment, as shown by the arrow C, it is possible to reduce the load difference in the breaking load compared with the comparative example shown by the arrow D.

[0085] In this embodiment, as shown in FIG. 4, since the number of column portions constituting the front side member 16 is two columns, the arrangement position of the room portion of one column portion is shifted by a half wavelength with respect to the room portion of the other column portion. However, the shifted wavelength may be different depending on the number of column portions. Further, the wavelength for shifting may be changed between the room portion of one column portion and the room portion of the other column portion along the longitudinal direction of the front side member 16.

[0086] Also, in this embodiment, as described above, the arrangement positions of the room portion 28 of the upper stage portion 18 and the room portion 32 of the lower stage portion 20 of the front side member 16 are shifted by a half wavelength along the longitudinal direction (vehicle front-rear direction) of the front side member 16. For this reason, a small room portion 34 is provided at the front end portion of the upper stage portion 18 in the front side member 16 in order to absorb the shift in the arrangement position that occurs between the room portion 28 and the room portion 32.

[0087] In this embodiment, the small room portion 34 makes it possible to align the positions of the front end surfaces of the upper stage portion 18 and the lower stage portion 20 (to be on the same plane), and when an impact load is input, it is possible to transmit the impact load substantially evenly to the upper stage portion 18 and the lower stage portion 20.

[0088] Also, in this embodiment, a convex portion 36 formed to have lower rigidity than other portions is provided along the vehicle width direction on the upper wall portion 34A of the small room portion 34. When an impact load is input to the front side member 16, the convex portion 36 serves as a starting point for deformation.

[0089] The small room portion 34 is less likely to undergo buckling deformation because the dimension along the vehicle front-rear direction is shorter compared to the other room portion 28. Therefore, in this embodiment, by promoting the deformation of the small room portion 34 starting from the convex portion 36, it is possible to suppress the remaining crush in the small room portion 34 and suppress the decrease in the absorption efficiency of the impact energy due to the remaining crush.

[0090] In addition, in the present embodiment, a convex portion (first vulnerable portion) 36 that is formed to be curved in an arc shape upward is provided on the upper wall portion 34A of the small room portion 34. However, it is not limited to this because it may be used as a starting point for deformation when an impact load is input along the longitudinal direction with respect to the front side member 16. For example, as shown in FIG. 8, a notch portion 56 that is cut out in a triangular shape upward may be formed on the inner surface side of the upper wall portion 34A of the small room portion 34.

[0091] Further, in the present embodiment, a small room portion 34 for absorbing a displacement in the arrangement position that occurs between the room portion 28 and the room portion 32 is provided at the front end portion of the upper stage portion 18 of the front side member 16. However, it is not limited to this. For example, as shown in FIG. 9, a small room portion 58 for absorbing a displacement in the arrangement position that occurs between the room portion 28 and the room portion 32 may be provided at the front end portion of the lower stage portion 20 of the front side member 16. In this case, a convex portion (first vulnerable portion) 36 that is formed to be curved in an arc shape downward is provided on the lower wall portion 34A of the small room portion 58.

[0092] Note that the small room portions 34 and 58 shown in FIGS. 4 and 9 are provided to absorb the displacement in the arrangement position between the upper stage portion 18 and the lower stage portion 20, but they are not necessarily required depending on the shape of the front side member 16.

[0093] Furthermore, in the present embodiment, as shown in FIG. 2, concave beads 42 and 44 are formed on the inner surface side of the room portion 28, and concave beads 48 and 50 are formed on the inner surface side of the room portion 32. These concave beads 42, 44, 48, and 50 are respectively formed along a direction intersecting the load input direction, and are used as starting points for deformation when an impact load is input. That is, in the present embodiment, it is possible to stabilize the fracture mode (described later) by deforming the room portion 28 (or the room portion 32) starting from the concave beads 42 and 44 (or the concave beads 48 and 50).

[0094] Here, the convex portion 36 is formed to be more easily deformable than the concave beads 42 and 44. As a result, in the present embodiment, the small room portion 34 is more likely to be broken than the room portion 28, and it becomes possible to effectively suppress the remaining crush in the small room portion 34. Note that the convex portion 36 is not necessarily required.

[0095] Further, in the present embodiment, the concave beads 42, 44, 48, and 50 are formed to have an arc-shaped cross-sectional shape along the width direction. However, since they may be used as the starting points of deformation when an impact load is input, they may form a triangular shape. Also, the cross-sectional shape, depth, etc. may be changed between the concave bead 42 and the concave bead 44, and between the concave bead 48 and the concave bead 50.

[0096] Furthermore, in the present embodiment, a concave bead 40 is provided on the outer surface side of the front side member 16. This concave bead 40 is provided at a position corresponding to the ribs 26 and 30, and is formed so as to be the starting point of deformation when an impact load is input.

[0097] In the present embodiment, since the room portions 28 and 32 are partitioned by the ribs 26 and 30 respectively, by providing the concave bead 40 at a position corresponding to the ribs 26 and 30, it becomes possible to prevent deformation from propagating between the adjacent room portions 28 and 32 along the load input direction.

[0098] As a result, in the present embodiment, it becomes possible to suppress the adjacent room portions 28 and 32 from being broken along the load input direction following the broken room portions 28 and 32, and it becomes possible to stabilize the failure mode in each room portion 28 and 32.

[0099] Also, in the present embodiment, a bead portion 46 is provided between the concave bead 44 and the rib 26 on the inner wall portion 18C of the upper stage portion 18, and a bead portion 52 is provided between the concave bead 48 and the rib 30 on the inner wall portion 20C of the lower stage portion 20. When an impact load is input to the front side member 16, they can be deformed starting from the bead portions 46 and 52 respectively.

[0100] As described above, in the present embodiment, by providing the concave bead 40, it is possible to prevent deformation from propagating between the adjacent room portions 28 (or room portions 32) along the load input direction by the rib 26 (or rib 30). Further, in the present embodiment, by providing the bead portion 46 (or bead portion 52) on the inner wall portion 16C of the front side member 16, the room portions 28 (or room portions 32) are deformed starting from the bead portion 46 (or bead portion 52) on the front side of the rib 26 (or rib 30), and it is possible to suppress the remaining crush around the rib 26 (or rib 30).

[0101] Here, for example, in the room portion 28 of the upper stage portion 18, concave beads 42 and 44 that are recessed outward from the room portion 28 are formed at the center in the vehicle front-rear direction, and a convex portion (fourth vulnerable portion) 46 that protrudes inward from the room portion 28 is formed on the rear side of the concave beads 42 and 44. And at the rear end of the room portion 28, a rib 26 is formed, and a concave bead 40 that is recessed inward from the room portion 28 corresponding to the rib 26 is formed.

[0102] That is, in the present embodiment, for example, in the room portion 28, uneven portions are alternately formed along the vehicle front-rear direction. Thereby, when an impact load is input to the front side member 16 and the front side member 16 is axially compressed, the front side member 16 can be deformed so as to be folded, the deformation mode of the front side member 16 can be controlled, and the remaining crush can be suppressed. Note that in the room portion 28, the concave beads 42 and 44, the bead portion 46, and the concave bead 40 are not necessarily required.

[0103] On the other hand, as shown in FIG. 5, in the present embodiment, the room portion 28 of the upper stage portion 18 and the room portion 32 of the lower stage portion 20 are formed such that the front end side of the front side member 16 (the upstream side in the load input direction in the impact absorption portion) is wider in the longitudinal direction (load input direction) of the front side member 16 than the rear end portion (downstream side).

[0104] Therefore, in the present embodiment, in the front side member 16, the front end portion side can have a greater breaking load than the rear end portion side, and when an impact load is input, the front end portion side of the front side member 16 can absorb more impact energy than the rear end portion side.

[0105] Also, in the present embodiment, the size of the chamber portion 28 of the upper stage portion 18 and the size of the chamber portion 32 of the lower stage portion 20 along the load input direction are substantially the same, but it is not limited thereto. For example, the size of the chamber portion 28 of the upper stage portion 18 can be appropriately changed according to the generated breaking load, such as making it larger than the chamber portion 32 of the lower stage portion 20. Further, for example, since the chamber portion 28 is partitioned by the rib 26, it will be provided at the front end and the rear end of the chamber portion 28 respectively, but a rib for increasing the breaking load may be separately provided at the central portion in the vehicle front-rear direction in the chamber portion 28.

[0106] By the way, in the present embodiment, the front side member 16 is formed by casting. Therefore, for example, compared with forming by extrusion molding, the degree of freedom in design is high in the shape of the front side member 16, and the manufacturing efficiency is improved.

[0107] Furthermore, in the present embodiment, the left and right front side members 16, the left and right wheel houses 14, and the cross member 15 are integrally formed by casting. Thereby, in the present embodiment, fasteners for fastening the left and right front side members 16 and the left and right wheel houses 14, and the left and right wheel houses 14 and the cross member 15 respectively become unnecessary, and the number of parts can be reduced. Note that these members do not necessarily have to be integrated, and of course, they may be formed as single units respectively.

[0108] Also, in the present embodiment, as shown in FIG. 5, the shapes of the ribs 26 and 30 at the open end 16G of the front side member 16 are different. Note that in FIGS. 2 and 4, the shape of the front side member 16 is schematized, and the arc portions 60, 62 and the triangular portion 64 described later are not shown.

[0109] As shown in FIG. 5, for example, on the upper wall portion 16A and the lower wall portion 16B sides of the front side member 16, arc portions 60 and 62 formed in an arc shape along the longitudinal direction of the front side member 16 are provided. However, on the partition wall 16D side of the front side member 16, a triangular portion 64 formed in a triangular shape with the rib 26 and 30 sides as the top is provided.

[0110] As described above, the front side member 16 in the present embodiment is formed by casting. Therefore, when the front side member 16 is released from the mold, an extrusion pin (not shown) abuts against the open end 16G on the outer shape side of the front side member 16, and the front side member 16 is pressed by the extrusion pin.

[0111] Therefore, in the present embodiment, a seating surface against which a substantially columnar extrusion pin abuts is required at the open end 16G on the outer shape side of the front side member 16. For this reason, the arc portion 60 is provided at the open end 16G of the front side member 16. Note that the arc portion 62 is formed larger than the arc portion 60, and may be used as a fixing seat for fixing a peripheral member of the front side member 16 to the front side member 16 via a fastening portion or the like.

[0112] Further, the ribs 26 and 30 of the front side member 16 are formed by branch flows branched from the main flow when the molten material flows in the mold. For this reason, in order to improve the flow of the molten metal into the branch flows, the triangular portion 64 is formed at the root portions of the ribs 26 and 30.

[0113] In the above embodiment, an example in which the front side member 16 is formed by casting has been described, but the present invention is not limited thereto. For example, the front side member 16 may be formed of CFRP (carbon fiber reinforced resin) in addition to metal. In this case, for example, it is formed by injection molding.

[0114] In the above-described embodiment, the front side member 16 has been described. However, the present invention is applicable not only to the front side member 16 but also to other skeletal members such as a rear side member 66 (see FIG. 1) and a suspension member (not shown).

[0115] As described above, one embodiment of the present invention has been described. However, the present invention is not limited to such an embodiment, and one embodiment and various modifications may be appropriately combined and used, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention.

[0116] <Supplementary Note> Note that the following configurations may be appropriately combined to form the vehicle lower structure according to the present invention.

[0117] (Configuration 1) It includes a shock absorption part for a vehicle that is formed by a mold and arranged along the input direction of an impact load, and the shock absorption part is arranged along a direction intersecting the load input direction, which is the input direction of the impact load, and a plurality of row parts are provided with open parts that are open in the arranged direction and a direction intersecting the load input direction, respectively.

[0118] (Configuration 2) The shock absorption part further includes a plurality of ribs that partition the inside of the open part into a plurality of room parts along the load input direction, and at least in part, the adjacent row parts are displaced in the arrangement position along the load input direction.

[0119] (Configuration 3) The ribs are displaced in the arrangement position along the load input direction between the row parts at least on the upstream side in the load input direction in the shock absorption part.

[0120] (Configuration 4) The room part is formed such that it is wider in the load input direction on the upstream side than on the downstream side in the load input direction in the shock absorption part.

[0121] (Configuration 5) The shock absorption part is provided by the displacement of the arrangement positions of the ribs generated along the load input direction between the column parts on the upstream side in the load input direction in the shock absorption part, and is formed with a small room part having a size smaller than the size of a preset room part, and a first weak part provided along a direction intersecting the load input direction in the small room part and serving as a starting point of deformation when the shock load is input, and is further configured to include.

[0122] (Configuration 6) On the inner surface side of the room part, a second weak part is provided which is formed along a direction intersecting the load input direction and serves as a starting point of deformation when the shock load is input.

[0123] (Configuration 7) The first weak part is formed to be more easily deformed than the second weak part.

[0124] (Configuration 8) On the outer surface side of the shock absorption part, at a position corresponding to the rib, a third weak part serving as a starting point of deformation when the shock load is input is provided along a direction intersecting the load input direction.

[0125] (Configuration 9) Two columns of the column parts are provided, and the second rib formed in the other column part is shifted by 1 / 2 wavelength with respect to the first rib formed in one column part.

[0126] (Configuration 10) The shock absorption part includes an upper wall part extending along the load input direction, a lower wall part extending along the load input direction and arranged on the opposite side of the upper wall part, and a side wall part extending along the load input direction and connecting one end of the upper wall part and one end of the lower wall part. The third weak part is provided on the upper wall part and the lower wall part. On the side wall part, a fourth weak part is formed along a direction intersecting the load input direction between the position corresponding to the second weak part along the load input direction and the third weak part, and the fourth weak part serves as a starting point of deformation when the shock load is input.

[0127] (Configuration 11) The shock absorption part is formed by casting.

[0128] (Configuration 12) The shock absorption part is a side member arranged along the vehicle front-rear direction at the end in the vehicle width direction, and the side member is integrally formed by casting with a wheel house where wheels are arranged.

[0129] (Configuration 13) The shock absorption part is left and right side members arranged along the vehicle front-rear direction at both ends in the vehicle width direction, and the side members are integrally formed by casting with wheel houses where left and right wheels are arranged and a cross member connecting the left and right wheel houses.

Explanation of Signs

[0130] 10 Vehicle 11 Shock Absorption Structure 14 Wheel House (Shock Absorption Structure) 15 Cross Member (Shock Absorption Structure) 16 Front Side Member (Shock Absorption Part, Shock Absorption Structure) 16A Upper Wall Part 16B Lower Wall Part 16C Inner Wall Part (Side Wall Part) 18 Upper Stage Part (Column Part) 20 Lower Stage Part (Column Part) 22 Open Part 24 Open part 26 Rib 27 Shock absorption part 28 Room part 30 Rib 32 Room part 34 Small room part 34A Upper wall part 36 Protrusion (first vulnerable part) 40 Concave bead (third vulnerable part) 42 Concave bead (second vulnerable part) 44 Concave bead (second vulnerable part) 46 Bead part (fourth vulnerable part) 48 Concave bead (second vulnerable part) 50 Concave bead (second vulnerable part) 52 Bead part (fourth vulnerable part) 56 Notch part (first vulnerable part) 58 Small room part

Claims

1. It is provided with a shock absorption part for a vehicle that is formed by a mold and arranged along the input direction of an impact load, wherein the shock absorption part is provided with a plurality of column parts that are arranged along a direction intersecting the load input direction, which is the input direction of the impact load, and each of the column parts is provided with an opening part that is open in the arranged direction and a direction intersecting the load input direction, a plurality of ribs that partition the inside of the opening part into a plurality of room parts along the load input direction, and at least some of the adjacent column parts are displaced in the arrangement position along the load input direction, and is configured to include a shock absorption structure.

2. The shock absorption structure according to claim 1, wherein the ribs are displaced in the arrangement position along the load input direction between the column parts at least on the upstream side in the load input direction in the shock absorption part.

3. The shock absorption structure according to claim 1, wherein the room parts are formed such that the upstream side in the load input direction in the shock absorption part is wider than the downstream side in the load input direction.

4. The shock absorption part on the upstream side in the load input direction in the shock absorption part, is provided by the displacement of the arrangement position of the ribs that occurs along the load input direction between the column parts, and is formed with a size smaller than a preset size of the room part, a small room part, and a first weak part that is provided along a direction intersecting the load input direction in the small room part and serves as a starting point of deformation when the shock load is input, and is further configured to include the shock absorption structure according to claim 2.

5. The shock absorption structure according to claim 1, wherein a second weak part that is formed along a direction intersecting the load input direction and serves as a starting point of deformation when the shock load is input is provided on the inner surface side of the room part.

6. The shock absorption structure according to claim 5, wherein the first weak part according to claim 4 is formed to be more easily deformed than the second weak part.

7. The shock absorption structure according to claim 1, wherein a third weak part that serves as a starting point of deformation when the shock load is input is provided along a direction intersecting the load input direction at a position corresponding to the ribs on the outer surface side of the shock absorption part.

8. The shock absorption structure according to claim 1, wherein two columns of the column parts are provided, and the second rib formed on one column part is displaced by 1 / 2 wavelength with respect to the first rib formed on the other column part.

9. The shock absorption part an upper wall portion extending along the load input direction; a lower wall portion extending along the load input direction and disposed on the opposite side of the upper wall portion; a side wall portion extending along the load input direction and connecting one end of the upper wall portion and one end of the lower wall portion; The impact absorption structure according to claim 1, comprising: The third weak portion according to claim 7 is provided on the upper wall portion and the lower wall portion; On the side wall portion, between a position corresponding to the second weak portion according to claim 5 along the load input direction and the third weak portion, a fourth weak portion is formed along a direction intersecting the load input direction and serves as a starting point of deformation when the impact load is input. The impact absorption structure according to claim 1.

10. The impact absorption structure according to claim 1, wherein the impact absorption portion is formed by casting.

11. The impact absorption portion is a side member disposed along the vehicle front-rear direction at an end in the vehicle width direction, and the side member is integrally formed by casting with a wheel house where a wheel is disposed. The impact absorption structure according to claim 1.

12. The impact absorption portion is left and right side members disposed along the vehicle front-rear direction at both ends in the vehicle width direction, and the side members are integrally formed by casting with wheel houses where left and right wheels are disposed and a cross member connecting the left and right wheel houses. The impact absorption structure according to claim 1.

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