Vehicle undercarriage

Abstract

Furthermore, the vehicle understructure is obtained that can more effectively absorb impact energy and suppress inward folding of the rocker. [Solution] The upper impact absorbing section 38, located on the upper side within the closed cross section 26 of the rocker 14, is provided along the vehicle width direction and includes a plurality of lateral wall sections connected to the vehicle inner wall section 24A of the rocker 14. The upper wall 38A, located above the plurality of lateral wall sections, is provided above the cross member 18. This reduces the load transmitted to the cross member 18 during a side collision with the vehicle, thereby suppressing deformation of the cross member 18. As a result, sufficient reaction force is obtained from the cross member 18, the upper impact absorbing section 38 undergoes plastic deformation, the impact energy is absorbed, and inward folding of the rocker 14 is suppressed.

Description

Technical Field

[0001] The present invention relates to a vehicle underbody structure.

Background Art

[0002] The following Patent Document 1 discloses a technology related to a vehicle underbody structure that supports a battery unit, which is one of the driving force supply devices, on the lower side of the vehicle of the floor panel. Specifically described, in this prior art, a square tubular battery side frame is disposed between the rocker and the battery unit and is attached adjacent to the rocker and the battery unit.

[0003] On the other hand, when an impact load is input to the rocker due to a side collision of the vehicle and the rocker is deformed toward the inside in the vehicle width direction (inside of the rocker), a tensile force acts on the inside in the vehicle width direction of the rocker. In the above prior art, as described above, since the battery side frame is provided adjacent to the rocker, a compressive force acts on the rocker side of the battery side frame..

[0004] <00―00015>That is, in the above prior art, in the rocker and the battery side frame, the stresses acting on each other cancel each other out between the tensile force and the compressive force acting on the adjacent parts. And thereby, the deformation of the rocker and the battery side frame is suppressed, and the intrusion (so-called inward folding) of the rocker into the inside in the vehicle width direction is suppressed.

Prior Art Document

Patent Document

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, if a large load is applied locally to the rocker, as in a so-called pole side impact, there is a possibility that the rocker may break inward.

[0007] Considering the above facts, the present invention aims to provide a vehicle understructure that can more effectively absorb impact energy and suppress inward bending of the rocker. [Means for solving the problem]

[0008] The vehicle understructure according to the first embodiment comprises a cross member extending in the vehicle width direction, a rocker disposed on the outside of the cross member in the vehicle width direction and extending in the vehicle longitudinal direction, and comprising a vehicle inner wall portion that constitutes the inside in the vehicle width direction and extends in the vehicle vertical direction and the vehicle longitudinal direction, thereby forming a closed section, and an upper impact absorbing portion disposed on the upper side of the closed section and extending in the vehicle width direction, wherein the upper impact absorbing portion comprises a plurality of lateral wall portions provided along the vehicle width direction and connected to the vehicle inner wall portion, and is arranged to overlap with the cross member in a vehicle side view, and the upper wall located above the plurality of lateral wall portions is offset from the cross member in the vehicle vertical direction and is provided above the cross member.

[0009] The vehicle understructure according to the first embodiment includes a cross member, a rocker, and an upper impact absorbing section. The cross member extends in the vehicle width direction, and the rocker is disposed on the outside of the cross member in the vehicle width direction and extends in the vehicle longitudinal direction. The rocker is also composed of an inner wall portion that constitutes the inside in the vehicle width direction and extends in the vehicle vertical direction and the vehicle longitudinal direction, forming a closed cross section.

[0010] The upper impact absorbing section is provided along the vehicle width direction and includes a plurality of lateral wall sections that connect to the vehicle inner wall section that constitutes the inside of the rocker in the vehicle width direction. In this embodiment, by providing the upper impact absorbing section within the closed cross section of the rocker which is located on the outside of the cross member in the vehicle width direction, when a vehicle is struck from the side, the impact is absorbed by the upper impact absorbing section before the load is applied to the cross member, thus reducing the impact load applied to the cross member in the initial stages of the side collision.

[0011] Furthermore, in this embodiment, the upper impact absorbing section is positioned so as to overlap with the cross member when viewed from the side of the vehicle. The upper wall, which is located above the other of the multiple side wall sections, is offset from the cross member in the vertical direction of the vehicle and is positioned above the cross member. In this way, in this embodiment, the upper wall of the upper impact absorbing section is offset from the cross member in the vertical direction, which reduces the load transmitted to the cross member compared to when their vertical positions coincide, thereby suppressing deformation of the cross member.

[0012] In this embodiment, the upper impact absorbing portion extends in the longitudinal direction of the vehicle within the closed cross-section of the rocker. Therefore, a portion of the impact load input to the rocker during a side collision of the vehicle (hereinafter referred to as "side collision of the vehicle") is transmitted inward in the vehicle width direction via the upper impact absorbing portion.

[0013] Generally, from the standpoint of protecting the passenger compartment, the rigidity of the rocker on the inner side in the vehicle width direction is high. Therefore, as in this embodiment, when a load is transmitted inward in the vehicle width direction via the upper impact absorbing part, a reaction force is generated against the rocker. As a result, the upper impact absorbing part undergoes plastic deformation, and the impact energy is absorbed.

[0014] Furthermore, in this embodiment, the cross member and the upper impact absorbing section are connected in the vehicle width direction with the inner wall portion of the rocker in between. Therefore, in the event of a side collision with the vehicle, a portion of the impact load applied to the rocker is transmitted to the cross member via the upper impact absorbing section. When an impact load is applied to the cross member, a reaction force is obtained from the cross member (more precisely, via the cross member, from the rocker on the opposite side from the rocker to which the impact load was applied).

[0015] As a result, the upper impact-absorbing section undergoes plastic deformation, absorbing impact energy, and even when a large localized load is applied to the rocker, such as a pole side impact, it becomes possible to suppress the inward bending of the rocker.

[0016] The vehicle understructure according to the second embodiment is the vehicle understructure according to the first embodiment, wherein the upper impact absorbing portion is integrally molded with the rocker and consists of a plurality of chambers arranged along the vehicle width direction, including the plurality of side wall portions.

[0017] In the vehicle understructure according to the second embodiment, the upper impact absorbing section is integrally molded with the rocker and includes a plurality of side wall sections, with a plurality of chamber sections arranged along the vehicle width direction. Here, as a comparative example, if the impact absorbing section is provided separately from the rocker as an impact absorbing member, when the impact absorbing member is placed within the closed cross section of the rocker, it is necessary to provide ribs or the like within the closed cross section to restrict the movement of the impact absorbing member in order to prevent the impact absorbing member from shifting position due to impact.

[0018] If such ribs are provided within the closed cross-section of a rocker, when an impact load is applied to the rocker and the impact absorbing member undergoes plastic deformation, the ribs may hinder the plastic deformation of the impact absorbing member. When the plastic deformation of the impact absorbing member is hindered in this way, so-called "remaining deformation" occurs, and the amount of impact energy absorbed by the rocker decreases by the amount of remaining deformation. In other words, there is a possibility that the impact energy cannot be absorbed efficiently.

[0019] In contrast, in this embodiment, since the upper impact absorbing portion is integrally molded with the rocker, there is no need to provide ribs or the like to restrict the movement of the impact absorbing member, and residual crushing of the upper impact absorbing portion can be suppressed. In other words, it becomes possible to effectively absorb the impact energy due to the collision load, and as a result, even if a large load is locally applied to the rocker, such as in a pole impact, it becomes possible to suppress inward bending of the rocker.

[0020] The vehicle understructure according to the third embodiment is configured such that, in the vehicle understructure according to the first embodiment, the rocker includes an upper rocker portion that forms an upper closed section portion that constitutes the upper part of the closed section portion, and a lower rocker portion that is provided on the lower side of the vehicle of the upper rocker portion and forms a lower closed section portion that constitutes the lower part of the closed section portion, and the upper impact absorbing portion is provided within the upper closed section portion.

[0021] In the vehicle understructure according to the third embodiment, the rocker is composed of an upper rocker and a lower rocker, with the upper rocker having an upper closed section that constitutes the upper part of the closed section. The lower rocker is provided on the lower side of the vehicle from the upper rocker, and the lower rocker has a lower closed section that constitutes the lower part of the closed section. In this embodiment, the upper impact absorbing part is provided within the upper closed section.

[0022] The vehicle understructure according to the fourth embodiment further comprises a lower impact absorbing portion extending in the vehicle width direction within the lower closed section, wherein the lower impact absorbing portion is integrally molded with the rocker and comprises a plurality of chambers arranged along the vehicle width direction.

[0023] In the vehicle understructure according to the fourth embodiment, a lower impact absorbing section extends in the vehicle width direction within the lower closed section. This lower impact absorbing section is integrally molded with the rocker and consists of a plurality of chambers arranged along the vehicle width direction.

[0024] The vehicle underbody structure according to the fifth aspect is the vehicle underbody structure according to the fourth aspect, in which a storage battery is disposed on the vehicle lower side of the cross member, and the lower shock absorber is disposed at a position overlapping the storage battery when viewed from the side of the vehicle.

[0025] In the vehicle underbody structure according to the fifth aspect, a storage battery is disposed on the vehicle lower side of the cross member, and the lower shock absorber is disposed at a position overlapping the storage battery when viewed from the side of the vehicle. Thus, in this aspect, a part of the impact load input to the rocker during a side collision of the vehicle is transmitted to the storage battery side through the lower shock absorber.

[0026] Generally, the storage battery mounted on the vehicle is set to have high rigidity. Therefore, in this aspect, a storage battery is disposed on the vehicle lower side of the cross member, and the lower shock absorber is disposed at a position overlapping the storage battery when viewed from the side of the vehicle. Thus, a part of the impact load input to the rocker during a side collision of the vehicle is transmitted to the storage battery side through the lower shock absorber.

[0027] As described above, since the storage battery is set to have high rigidity, when an impact load is input to the storage battery, a reaction force can be obtained from the storage battery. Thereby, the lower shock absorber is plastically deformed and the impact energy is absorbed. That is, even if it is a short stroke, it is possible to reduce the impact load.

[0028] In addition, the impact load transmitted to the storage battery through the lower shock absorber of the rocker can suppress the intrusion (so-called inward folding) of the rocker inward in the vehicle width direction by obtaining a reaction force from the storage battery.

[0029] Examples of the "storage battery" include a lithium ion battery, a nickel hydrogen battery, a silicon battery, and the like. Further, the "storage battery" here refers to, for example, a state in which a plurality of battery modules are housed in a case (hereinafter referred to as a "battery pack").

[0030] In this embodiment, an upper impact absorbing section and a lower impact absorbing section extend in the vehicle width direction within the closed section of the rocker. The lower impact absorbing section is positioned to overlap with the battery in a side view of the vehicle, and the upper impact absorbing section is positioned to overlap with the cross member in a side view of the vehicle. Therefore, in the event of a side collision with a vehicle, a portion of the impact load applied to the rocker is transmitted to the battery side via the lower impact absorption section and to the cross member side via the upper impact absorption section. When an impact load is applied to the battery, a reaction force is obtained from the battery, and when an impact load is applied to the cross member, a reaction force is obtained from the cross member. As a result, the lower and upper impact absorption sections undergo plastic deformation, and the impact energy is absorbed.

[0031] Furthermore, in the event of a vehicle side collision, a load transmission path can be formed that transmits the load to the battery side via the lower impact absorption section of the rocker, and a load transmission path that transmits the load to the cross member side via the upper impact absorption section of the rocker. Therefore, it becomes possible to distribute the impact load applied to the rocker.

[0032] In other words, in this embodiment, a lower shock absorbing section and an upper shock absorbing section are provided within the closed cross section of the rocker, and these lower and upper shock absorbing sections are positioned so as to overlap with the battery and cross member, respectively, when viewed from the side of the vehicle, thereby suppressing inward bending of the rocker by utilizing the reaction forces from the battery and cross member.

[0033] The vehicle understructure according to the sixth embodiment is a vehicle understructure according to the third embodiment, wherein the lower wall portion of the lower part of the rocker is provided with a fastening portion that fastens to a storage battery disposed on the lower side of the vehicle of the cross member, and the cross member extends outward in the vehicle width direction from the fastening portion.

[0034] In the vehicle understructure according to the sixth embodiment, a fastening portion for fastening to a storage battery is provided on the lower wall of the lower part of the rocker, and the cross member extends outward in the vehicle width direction beyond the said fastening portion. [Effects of the Invention]

[0035] As described above, the vehicle understructure according to the present invention has the excellent effect of effectively absorbing impact energy with the upper impact absorbing section and suppressing inward bending of the rocker. [Brief explanation of the drawing]

[0036] [Figure 1] This is a plan view of the underside of a vehicle to which the vehicle understructure according to the first embodiment is applied. [Figure 2] This is a cross-sectional view taken along line 2-2 in Figure 1. [Figure 3] (A) and (B) are schematic diagrams showing, in chronological order, the state in which an impact load is applied to the rocker of a vehicle to which the vehicle understructure according to the first embodiment is applied. [Figure 4] (C) and (D) are schematic diagrams showing, in chronological order, the state in which an impact load is applied to the rocker of a vehicle to which the vehicle understructure according to the first embodiment is applied. [Figure 5] (A) and (B) are comparative examples and schematic diagrams showing the time series of impact loads applied to the vehicle's rocker. [Figure 6] (C) and (D) are comparative examples and schematic diagrams showing the time series of impact loads applied to the vehicle's rocker. [Figure 7] This is a cross-sectional view corresponding to Figure 2, showing a modified example of the vehicle understructure according to the first embodiment. [Figure 8] This is a cross-sectional view corresponding to Figure 2, showing the vehicle understructure according to the second embodiment. [Figure 9] This is a cross-sectional view corresponding to Figure 2, showing a first modified example of the vehicle understructure according to the second embodiment. [Figure 10] This is a cross-sectional view corresponding to Figure 2, showing a second modified example of the vehicle understructure according to the second embodiment. [Modes for carrying out the invention]

[0037] A vehicle understructure according to an embodiment of the present invention will be described with reference to the drawings. The arrows FR, UP, and RH in each figure indicate, respectively, the vehicle understructure according to one embodiment of the present invention. This shows the forward, upward, and rightward directions of a vehicle to which the floor structure is applied. Hereafter, when simply using the directions of front / rear, up / down, and left / right, unless otherwise specified, these refer to the front / rear direction of the vehicle, the up / down direction of the vehicle, and left / right when facing forward.

[0038] <First Embodiment> (Vehicle understructure configuration)

[0039] First, the configuration of the vehicle understructure according to this embodiment will be described. Figure 1 shows a plan view of the vehicle underside 10 to which the vehicle understructure according to this embodiment is applied, and Figure 2 shows a cross-sectional view of Figure 1 when cut along line 2-2.

[0040] As shown in Figure 1, a floor panel 12 extends from the lower part of the vehicle 10 along the vehicle width direction and the vehicle longitudinal direction. Bead portions 12A are intermittently projected from the floor panel 12 along the vehicle longitudinal direction, and multiple bead portions 12A are arranged along the vehicle width direction. The formation of these bead portions 12A improves the rigidity of the floor panel 12 itself.

[0041] Furthermore, rockers 14 and 16 extend from both ends of the floor panel 12 in the vehicle width direction, respectively, along the vehicle's longitudinal direction. A cross member 18 is placed on top of the floor panel 12, between the rockers 14 and 16, along the vehicle width direction. The cross member 18 is positioned between the bead portions 12A arranged along the vehicle's longitudinal direction.

[0042] As shown in Figure 2, a battery pack (rechargeable battery) 20 is installed on the lower side of the floor panel 12 as a drive force supply device for supplying power to power units such as motors.

[0043] As mentioned above, rockers 14 and 16 extend from both ends of the floor panel 12 in the vehicle width direction, respectively, along the vehicle's longitudinal direction. The rockers 14 and 16 will be described below. Note that rocker 16 has almost the same configuration as rocker 14, so its description will be omitted.

[0044] As shown in Figure 2, in this embodiment, the rocker 14 is composed of an outer portion 22 located on the outside in the vehicle width direction and an inner portion 24 located on the inside in the vehicle width direction. The rocker 14 is made of a metal such as an aluminum alloy, and the outer portion 22 and the inner portion 24 are integrally formed by extrusion or drawing, and the outer portion 22 and the inner portion 24 form a closed cross-section 26.

[0045] The outer portion 22 is composed of an outer wall portion 22A formed in the vertical direction in a cross-sectional shape cut along the vehicle width direction, an inclined upper wall portion 22B provided above the outer wall portion 22A and inclined upward as it moves inward in the vehicle width direction, and an inclined lower wall portion 22C provided below the outer wall portion 22A and inclined downward as it moves inward in the vehicle width direction.

[0046] On the other hand, the inner portion 24, in a cross-sectional shape cut along the vehicle width direction, is composed of an upper inner wall portion 24A formed vertically on the upper side of the inner portion 24 and a lower inner wall portion 24B formed vertically on the lower side of the inner portion 24. This lower inner wall portion 24B is located further inward in the vehicle width direction than the upper inner wall portion 24A, and a lateral wall portion 24C formed substantially horizontally is provided between the lower inner wall portion 24B and the upper inner wall portion 24A. Therefore, the lateral wall portion 24C is formed to connect with the lower inner wall portion 24B and the upper inner wall portion 24A.

[0047] Furthermore, above the upper inner wall portion 24A, there is an inclined upper wall portion 24D that slopes upward as it extends outward in the vehicle width direction, and this inclined upper wall portion 24D is formed to connect with the inclined upper wall portion 22B of the outer portion 22. A flange portion 28 extends upward from the top portion 27 where the inclined upper wall portion 24D of the inner portion 24 and the inclined upper wall portion 22B of the outer portion 22 connect. The lower end of a pillar (not shown) is connected to this flange portion 28.

[0048] Furthermore, a bottom wall portion 24E is provided on the lower side of the lower inner wall portion 24B, formed substantially horizontally toward the outside in the vehicle width direction, and this bottom wall portion 24E is formed to connect with the inclined lower wall portion 22C of the outer portion 22. A fastener (fastening part) 32 can be inserted through the bottom wall portion 24E, and the fixing piece 30 provided on the battery pack 20 can be fastened and fixed to the rocker 14 via the fastener 32.

[0049] As mentioned above, the upper inner wall portion 24A of the inner portion 24 is located further outward in the vehicle width direction than the lower inner wall portion 24B. As a result, the area of ​​the closed section differs between the upper (upper) 14A and the lower (lower) 14B of the rocker 14. In other words, the area of ​​the lower closed section 34 provided on the lower 14B side of the rocker 14 is larger than the area of ​​the upper closed section 36 provided on the upper 14A side of the rocker 14, and the rigidity of the lower 14B side of the rocker 14 is set to be higher than that of the upper 14A side of the rocker 14.

[0050] Furthermore, a ladder-shaped shock-absorbing section (upper shock-absorbing section) 38 is provided within the upper closed section 36 of the rocker 14, and this shock-absorbing section 38 is positioned to overlap with the cross member 18 when viewed from the side of the vehicle. In addition, a ladder-shaped shock-absorbing section (lower shock-absorbing section) 40 is formed within the lower closed section 34 of the rocker 14, and this shock-absorbing section 40 is positioned to overlap with the battery pack 20 when viewed from the side of the vehicle.

[0051] Now, let's explain the shock-absorbing sections 38 and 40, respectively. The shock-absorbing sections 38 and 40 are integrally formed with the outer section 22 and the inner section 24. The shock-absorbing section 38 includes an upper wall (side wall section) 38A that spans substantially horizontally (vehicle width direction) between the upper inner wall section 24A of the inner section 24 and the outer wall section 22A of the outer section 22. Below this upper wall 38A, a lower wall 38B is formed opposite to the upper wall 38A, and this lower wall 38B is connected to the side wall section 24C, dividing the upper section 14A and the lower section 14B of the rocker 14. Furthermore, the space between the upper wall 38A and the lower wall 38B is spanned vertically by a plurality (in this case, two) of connecting walls 38C. The plurality of compartments described in claim 2 are formed by a plurality of connecting walls 38C.

[0052] On the other hand, the impact-absorbing section 40 includes an upper wall 40A that spans the space between the lower inner wall 24B of the inner section 24 and the outer wall 22A of the outer section 22 in a substantially horizontal direction (vehicle width direction). Below this upper wall 40A, a lower wall 40B is formed opposite to the upper wall 40A, and the space between the upper wall 40A and the lower wall 40B is spanned vertically by a plurality (in this case, three) of connecting walls 40C. The plurality of chambers described in claim 4 are formed by a plurality of connecting walls 40C.

[0053] (Function and effect of the vehicle's understructure) Next, the operation and effects of the vehicle understructure according to this embodiment will be described.

[0054] As shown in Figure 2, in this embodiment, the outer portion 22 and the inner portion 24 of the rocker 14 are integrally formed, and the outer portion 22 and the inner portion 24 form a closed cross-section 26.

[0055] This allows for increased strength compared to, for example, a case where the rocker is formed by joining two panels, an outer part and an inner part, together (though not shown in the diagram). Furthermore, while welding or fastening is required when joining two panels, an outer part and an inner part, in this embodiment, the outer part 22 and the inner part 24 are integrally formed, eliminating the need for such processing and thus reducing costs.

[0056] Furthermore, in this embodiment, in the upper part 14A of the rocker 14 (within the upper closed section 36), an impact absorbing section 38 is stretched in the vehicle width direction between the outer section 22 and the inner section 24 at a position that overlaps with the cross member 18 when viewed from the side of the vehicle. Also, in the lower part 14B of the rocker 14 (within the lower closed section 34), an impact absorbing section 40 is stretched in the vehicle width direction between the outer section 22 and the inner section 24 at a position that overlaps with the battery pack 20 when viewed from the side of the vehicle.

[0057] Therefore, when a vehicle is involved in a side collision, if an impact load F is input to the rocker 14, a portion of the impact load F is transmitted to the cross member 18 side via the impact absorption section 38 provided on the upper side 14A of the rocker 14 (transmitted load F1), and transmitted to the battery pack 20 side via the impact absorption section 40 provided on the lower side 14B of the rocker 14 (transmitted load F2).

[0058] When an impact load (transmitted load F1) is transmitted to the cross member 18 via the impact absorption section 38, a reaction force N1 is obtained in the rocker 14 from the cross member 18 (more precisely, from the rocker 16 on the opposite side of the rocker 14 to which the impact load F was input (see Figure 1)) via the cross member 18. Also, when an impact load (transmitted load F2) is transmitted to the battery pack 20 via the impact absorption section 40, a reaction force N2 is obtained in the rocker 14 from the battery pack 20. As a result, the impact absorption sections 38 and 40 undergo plastic deformation, and the impact energy is absorbed.

[0059] Here, for example, as shown in Figures 5(A), (B) and 6(C), (D), if the shock absorbing section is provided separately from the rocker 102 as a shock absorbing member 100, when the shock absorbing member 100 is placed inside the closed section 104 of the rocker 102, it is necessary to provide movement-restricting ribs 106 inside the closed section 104 to prevent the shock absorbing member 100 from shifting position due to impact.

[0060] Thus, when a movement-restricting rib 106 is provided within the closed cross-section 104 of the rocker 102, when an impact load F is applied to the rocker 102 and the impact absorbing member 100 undergoes plastic deformation, the plastic deformation of the impact absorbing member 100 may be hindered by the rib 106, as shown in Figures 6(C) and (D).

[0061] In this way, if the plastic deformation of the impact absorbing member 100 is inhibited, a so-called "remaining crushed portion" (remaining crushed portion 108) will occur, and the amount of impact energy absorbed by the rocker 102 will decrease by the amount of this remaining crushed portion. In other words, there is a possibility that the impact energy cannot be absorbed efficiently.

[0062] In contrast, in this embodiment, as shown in Figures 3(A), (B) and 4(C), (D), the impact absorbing portion 40 is integrally formed with the outer portion 22 and the inner portion 24, so there is no need to provide ribs or the like, as shown in Figure 5(A). Therefore, in this embodiment, as shown in Figures 4(C), (D), residual deformation of the impact absorbing portion 40 can be suppressed.

[0063] In other words, it becomes possible to effectively absorb the impact energy caused by the collision load F, thereby suppressing inward bending of the rocker 14 even when a large load is locally applied to the rocker 14, such as in a pole impact. To put it another way, in this embodiment, by suppressing the remaining deformation of the impact absorption part 40, impact energy can be absorbed even more effectively, and inward bending of the rocker 14 can be suppressed.

[0064] In this embodiment, as shown in Figure 2, the shock-absorbing sections 38 and 40 are provided within the closed cross-section 26 of the rocker 14. On the other hand, in Figures 3 and 4, only the shock-absorbing section 40 is provided within the closed cross-section 26 of the rocker 14. This is to match the configurations shown in Figures 5 and 6 as comparative examples, and the same can be said for the shock-absorbing sections 38 and 40 in this embodiment, so they are not shown.

[0065] By the way, in this embodiment shown in Figure 2, as described above, when an impact load F is input to the rocker 14 during a side collision of the vehicle, a portion of the impact load F is transmitted to the cross member 18 side via the impact absorption section 38 provided on the upper 14A side of the rocker 14 (transmitted load F1), and transmitted to the battery pack 20 side via the impact absorption section 40 provided on the lower 14B side of the rocker 14 (transmitted load F2).

[0066] In other words, here, a load transmission path A is formed that transmits the load to the cross member 18 side via the shock absorption section 38 of the rocker 14, and a load transmission path B is formed that transmits the load to the battery pack 20 side via the shock absorption section 40 of the rocker 14. This makes it possible to distribute the shock load F input to the rocker 14, and it is also possible to change the proportion of load bearing between the upper part 14A and the lower part 14B of the rocker 14.

[0067] Therefore, the impact load F2 transmitted to the battery pack 20 located below the floor panel 12 can be reduced. As a result, for example, the rigidity of the battery pack 20 itself can be reduced by the amount by which the impact load F2 transmitted to the battery pack 20 is reduced. In this case, the thickness of the battery pack 20 can be reduced, thereby making the battery pack 20 lighter. In addition, the amount of battery modules 20A housed inside the battery pack 20 can be increased by the amount by which the thickness of the battery pack 20 is reduced.

[0068] (Supplementary information for this embodiment) In this embodiment, the shock-absorbing sections 38 and 40 are each formed in a ladder shape, but the shape of the shock-absorbing sections 38 and 40 is not limited to this. For example, the shape can be appropriately changed in relation to the plate thickness, such as forming a honeycomb shape by making the plate thickness thinner. Also, the plate thickness of the shock-absorbing section 38 and 40 may be different, and the shock-absorbing sections 38 and 40 do not necessarily have to be the same shape.

[0069] Furthermore, in this embodiment, the rocker 14 is provided with an impact absorbing section 38 at a position that overlaps with the cross member 18 when viewed from the side of the vehicle, and an impact absorbing section 40 is provided at a position that overlaps with the battery pack 20 when viewed from the side of the vehicle. However, the embodiments to which the present invention is applied are not limited to these.

[0070] For example, as shown in Figure 7, some vehicle models do not have a cross member 18 (see Figure 2) on top of the floor panel 12. In this case, no impact absorbing section is provided on the upper 42A side of the rocker 42 that overlaps with the cross member 18 (see Figure 2) in a side view of the vehicle. Therefore, an impact absorbing section (first impact absorbing section) 40 is provided on the lower 42B side of the rocker 42. When an impact load F is input to the rocker 14 during a side collision, a portion of the impact load F is transmitted to the battery pack 20 side via the impact absorbing section 40 (transmitted load F3).

[0071] Then, when an impact load (transmitted load F3) is transmitted to the battery pack 20 via the impact absorption section 40, a reaction force N3 is obtained from the battery pack 20 in the rocker 14. As a result, the impact absorption section 40 undergoes plastic deformation, and even in this case, the impact energy is absorbed.

[0072] <Second Embodiment> In the first embodiment described above, a case was described in which a battery pack 20 (see Figure 2) was used as a driving force supply device for supplying power to the power unit. In this embodiment, as shown in Figure 8, a case will be described in which a hydrogen tank 44, which is a fuel cell, is used as a driving force supply device. Note that the explanation of configurations that are substantially the same as in the first embodiment will be omitted. The embodiments applicable in the present invention are not limited to these.

[0073] In this case, when a vehicle is involved in a side collision, the impact load applied to the rocker is transmitted to the cross member located on the floor panel. Therefore, if the fuel cell is located on the lower side of the floor panel, it is preferable that the impact load is not applied to the fuel cell.

[0074] As shown in Figure 8, in this embodiment, the rocker 46 is provided with an impact absorbing section 38 at a position that does not overlap with the hydrogen tank 44 when viewed from the side of the vehicle (on the upper part 46A side of the rocker 46).

[0075] In this case, when a vehicle is struck from the side, an impact load F is input to the rocker 46. A portion of this impact load F is transmitted to the cross member 18 via an impact absorption section 38 provided on the upper part 46A of the rocker 46 (transmitted load F4). When the impact load (transmitted load F4) is transmitted to the cross member 18 via the impact absorption section 38, the rocker 46 receives a reaction force N4 from the cross member 18. As a result, the impact absorption section 38 undergoes plastic deformation, and the impact energy is absorbed.

[0076] In other words, even with a short stroke, it is possible to reduce the impact load F, and the inward intrusion of the rocker 46 in the vehicle width direction can be suppressed. Furthermore, in this embodiment, it is possible to prevent the impact load F from being input to the hydrogen tank 44 located below the floor panel 12.

[0077] (Supplementary information for this embodiment) In the embodiments described above, as shown in Figure 1, the cross member 18 is spanned between the rockers 14 and 16. However, for example, as shown in Figure 9, if the hydrogen tank 47 is large in diameter, the hydrogen tank 47 may be arranged along the vehicle's longitudinal direction below the tunnel section 50 that protrudes along the vehicle's longitudinal direction from the center of the floor panel 48 in the vehicle's width direction.

[0078] In this case, the cross member 52 is spanned between a pair of rockers 54 located at both ends of the floor panel 48 in the vehicle width direction, with the tunnel section 50 in between. In this example, the cross member 52 is formed to conform to the shape of the tunnel section 50, but it is not limited to this.

[0079] For example, although not shown in the diagram, the cross member may be divided by the tunnel section and provided in two sections along the vehicle width direction. However, in this case, one longitudinal end of the cross member will be connected to the rocker, and the other longitudinal end of the cross member will be connected to the tunnel section. Therefore, the impact load transmitted from the rocker to the cross member will receive a reaction force from the tunnel section.

[0080] Furthermore, although the above embodiments describe vehicles using a battery pack 20 (see Figure 2) and a hydrogen tank 44 (see Figure 8) as a power supply device, these embodiments are also applicable to gasoline-powered vehicles.

[0081] In the case of gasoline vehicles, for example, as shown in Figure 10, there is no need to install a drive force supply device on the lower side of the floor panel 56, therefore the vertical direction of the floor panel 56 The position can be set low. For this reason, the impact absorbing section (first impact absorbing section) 60, which is provided so as to overlap with the cross member 58 positioned on the floor panel 56 when viewed from the side of the vehicle, is provided on the lower 62A side of the rocker 62.

[0082] Although an example of an embodiment of the present invention has been described above, the embodiments of the present invention are not limited to those described above. One embodiment and various modifications may be used in appropriate combinations, and it goes without saying that the invention can be implemented in various forms without departing from the spirit of the present invention. [Explanation of Symbols]

[0083] 10. Underbody of the vehicle (underbody structure) 14 Rocka 14A Upper part (top of rocker) 14B Lower part (Lower part of the rocker) 16 Rocka 18 Cross Member 20 Battery packs (rechargeable batteries) 24A Upper inner wall section (inner wall section of the vehicle) 26 Closed section 32 Fasteners (fastening parts) 34 Lower closed section 36 Upper closed section 38. Impact absorbing section (upper impact absorbing section, rocker) 38A Upper wall (side wall) 40. Shock-absorbing section (lower shock-absorbing section, rocker) 42 Rocka 46 Rocka 52 Crossmember 54 Rocka 58 Cross Member 60. Impact absorbing section (lower impact absorbing section) 62 Rocka

Claims

1. A cross member extending in the vehicle width direction, A rocker is disposed on the outside of the cross member in the vehicle width direction and extends in the vehicle longitudinal direction, and is configured to include a vehicle inner wall portion that constitutes the inside in the vehicle width direction and extends in the vehicle vertical direction and the vehicle longitudinal direction, thereby forming a closed cross section. An upper impact absorbing portion is located on the upper side within the closed cross-section and extends in the vehicle width direction, Equipped with, The upper impact absorbing section is provided along the vehicle width direction and includes a plurality of lateral wall sections connected to the vehicle inner wall section. Furthermore, the vehicle understructure is arranged so as to overlap with the cross member when viewed from the side of the vehicle, and the upper wall, which is located above the plurality of side wall portions, is offset from the cross member in the vertical direction of the vehicle and is provided above the cross member.

2. The vehicle understructure according to claim 1, wherein the upper impact absorbing portion is integrally molded with the rocker and comprises a plurality of chambers arranged along the vehicle width direction, including the plurality of side wall portions.

3. The aforementioned rocker, The upper rocker portion forming the upper closed section portion which constitutes the upper part of the closed section portion, The lower part of the rocker is provided on the lower side of the vehicle above the upper part of the rocker and forms a lower closed section that constitutes the lower part of the closed section, It consists of, The vehicle understructure according to claim 1, wherein the upper impact absorbing portion is provided within the upper closed cross section.

4. Within the aforementioned lower closed section, there is further a lower impact absorbing section extending in the vehicle width direction, The lower impact absorbing portion is integrally molded with the rocker and consists of a plurality of chambers arranged along the vehicle width direction, as described in claim 3.

5. The vehicle understructure according to claim 4, wherein a storage battery is disposed on the lower side of the cross member, and the lower impact absorbing portion is positioned to overlap with the storage battery when viewed from the side of the vehicle.

6. The lower wall portion of the lower part of the rocker is provided with a fastening portion that fastens to a storage battery disposed on the lower side of the vehicle of the cross member, and the cross member extends outward in the vehicle width direction from the fastening portion, as described in claim 3.

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