Vehicle undercarriage

Abstract

To obtain a vehicle lower structure that is able to hinder inward break of a rocker by absorbing impact energy more effectively.SOLUTION: In a rocker 14, an outer part 22 and an inner part 24 are integrally formed, and impact absorbing parts 38, 40 are formed integrally with the outer part 22 and inner part 24. This eliminates the need for a rib or the like for preventing displacement of impact absorbing members in the event of impact application. Therefore, residual crash due to formation of the rib does not occur. Thus, impact energy due to collision load F can effectively be absorbed and, even in the event that large load is locally input to the rocker 14 as in a case of side collision with a pole, inward break of the rocker 14 can be hindered. In other words, by hindering residual crash of the impact absorbing parts 38, 40, impact energy can be absorbed more effectively and inward break of the rocker 14 can be hindered.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Patent Document 1 below discloses a technique 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 arranged 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] 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 Documents

Patent Documents

[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] First aspect The vehicle understructure in question comprises a cross member extending in the vehicle width direction, and a component disposed on the outside of the cross member in the vehicle width direction and in the vehicle longitudinal direction. It extends in the vehicle width direction and includes an inner wall portion of the vehicle that extends in the vehicle vertical direction and in the vehicle longitudinal direction. , rocker forming a closed section, and inside the closed section Located on the upper side and extending in the vehicle width direction It comprises an upper shock-absorbing section, The upper impact absorbing portion does not have a vertical wall portion that overlaps the inner wall portion of the vehicle within the closed cross section, and is further configured to include a horizontal wall portion that is provided along the vehicle width direction and is connected to the inner wall portion of the vehicle, and the cross member and the horizontal wall portion of the upper impact absorbing portion are connected in the vehicle width direction via the inner wall portion of the vehicle. .

[0009] First aspect The vehicle understructure in this respect 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 also includes an inner wall portion that constitutes the inside in the vehicle width direction and extends in the vehicle vertical and longitudinal directions, forming a closed section. The upper impact absorbing section is located on the upper side of the closed section and extends in the vehicle width direction.

[0010] Here, The upper impact absorbing section does not have vertical walls that overlap with the inner vehicle wall provided on the rocker within the closed cross section of the rocker, and is configured to include horizontal walls that are provided along the vehicle width direction and connect to the said inner vehicle wall. The cross member and the horizontal wall of the upper impact absorbing section are connected in the vehicle width direction via the inner vehicle wall.

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

[0013] Generally, from the standpoint of protecting the interior of the vehicle, the rigidity of the rocker on the inside in the vehicle width direction is increased. manner As shown above, when a load is transmitted inward in the vehicle width direction via the upper shock absorber, a reaction force is generated against the rocker. As a result, the upper shock absorber undergoes plastic deformation, and the impact energy is absorbed. Also, book manner In this configuration, the cross member and the upper impact absorbing section are connected in the vehicle width direction, with the inner wall of the rocker in between. Therefore, during a side collision, 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, from the rocker on the opposite side from the rocker that received the impact load, via the cross member). As a result, the upper impact absorbing section undergoes plastic deformation, absorbing the impact energy, and preventing the rocker from bending inward even when a large localized load is applied to it, such as in a pole collision.

[0014] Second aspect The vehicle understructure related to this is First aspect In the vehicle understructure relating to the above, the upper impact absorbing part is integrally molded with the rocker, Including the aforementioned side wall portion It consists of multiple compartments arranged along the width of the vehicle. Second aspect In the vehicle understructure related to this, the upper impact absorbing section is integrally molded with the rocker. Including the side wall section Multiple compartments are arranged along the width of the vehicle. Here, as a comparative example, if the shock-absorbing section is provided separately from the rocker as a shock-absorbing member, when the shock-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 shock-absorbing member in order to prevent the shock-absorbing member from shifting position due to impact.

[0015] When such ribs are provided within the closing surface portion of the rocker, when an impact load is input to the rocker and the impact absorbing member plastically deforms, the plastic deformation of the impact absorbing member may be inhibited by the ribs. Thus, when the plastic deformation of the impact absorbing member is inhibited, so-called residual crushing occurs, and the amount of impact energy absorbed by the rocker decreases by the amount of residual crushing. That is, there is a possibility that the impact energy cannot be efficiently absorbed.

[0016] In contrast, in this manner the upper impact absorbing portion is integrally formed with the rocker, so there is no need to provide ribs or the like for restricting the movement of the impact absorbing member, and residual crushing of the upper impact absorbing portion can be suppressed. That is, it becomes possible to effectively absorb the impact energy due to the collision load, and thereby, even when a locally large load is input to the rocker, such as in a pole side collision, it is possible to suppress the inward bending of the rocker.

[0017] Third aspect The vehicle underbody structure according to First aspect In the vehicle underbody structure according to, the rocker includes a rocker upper portion that forms an upper closing surface portion that constitutes the upper part of the closing surface portion, and a rocker lower portion that is provided on the vehicle lower side of the rocker upper portion and forms a lower closing surface portion that constitutes the lower part of the closing surface portion, and the upper impact absorbing portion is provided within the upper closing surface portion. Third aspect In the vehicle underbody structure according to, the rocker is configured to include a rocker upper portion and a rocker lower portion. An upper closing surface portion that constitutes the upper part of the closing surface portion is formed in the rocker upper portion. Further, the rocker lower portion is provided on the vehicle lower side of the rocker upper portion, and a lower closing surface portion that constitutes the lower part of the closing surface portion is formed in the rocker lower portion. Here, in this manner the upper impact absorbing portion is provided within the upper closing surface portion.

[0018] Fourth aspect The vehicle underbody structure according to Third aspectIn the vehicle understructure relating to the above, the lower closed cross section further comprises a lower impact absorbing portion extending in the vehicle width direction, the lower impact absorbing portion being integrally molded with the rocker and comprising a plurality of chambers arranged along the vehicle width direction. Fourth aspect In the vehicle understructure relating to this, a lower impact absorbing section extends in the vehicle width direction within the lower closed cross-section. This lower impact absorbing section is integrally molded with the rocker and consists of multiple chambers arranged along the vehicle width direction. Fifth aspect The vehicle understructure related to this is Fourth aspect In the vehicle understructure relating to the above, a storage battery is arranged on the lower side of the vehicle of the cross member, and the lower impact absorbing part is positioned to overlap with the storage battery when viewed from the side of the vehicle. Fifth aspect In the vehicle understructure related to this, the battery is located on the lower side of the cross member, and the lower impact absorbing section is positioned to overlap with the battery when viewed from the side of the vehicle. manner Therefore, a portion of the impact load applied to the rocker during a vehicle side collision will be transmitted to the battery side via the lower impact absorption section. Generally, batteries mounted on vehicles are designed to have high rigidity. For this reason, in this invention, the battery is positioned on the lower side of the vehicle of the cross member, and the lower impact absorption section is positioned to overlap with the battery when viewed from the side of the vehicle. As a result, a portion of the impact load input to the rocker during a side collision of the vehicle is transmitted to the battery side via the lower impact absorption section.

[0019] As mentioned above, since the battery is designed to have high rigidity, when an impact load is applied to the battery, a reaction force is generated from the battery. As a result, lower side The shock-absorbing section undergoes plastic deformation, absorbing the impact energy. This means that even with a short stroke, it is possible to reduce the impact load.

[0020] Also, Rocca lower sideThe impact load transmitted to the battery via the shock-absorbing section can be counteracted by the reaction force from the battery, thereby suppressing the rocker's inward movement in the vehicle width direction (so-called inward bending).

[0021] Examples of "rechargeable batteries" include lithium-ion batteries, nickel-metal hydride batteries, and silicon batteries. Furthermore, "rechargeable battery" here refers to a state in which multiple battery modules are housed in a case (hereinafter referred to as a "battery pack").

[0022] By the way, this book manner Within the closed section of the rocker, an upper impact absorbing section and a lower impact absorbing section extend in the vehicle width direction. The lower impact absorbing section is positioned to overlap with the battery when viewed from the side of the vehicle, and the upper impact absorbing section is positioned to overlap with the cross member when viewed from the side 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.

[0023] 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. In other words, book manner Therefore, 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, and the reaction force from the battery and cross member is utilized to suppress inward bending of the rocker.

[0024] Sixth aspect The vehicle understructure related to this is Third aspect In the vehicle understructure relating to the above, the lower wall portion of the lower part of the rocker is provided with a fastening portion that fastens to a storage battery located 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. Sixth aspect In the vehicle understructure relating to this, a fastening portion for fastening to the battery is provided on the lower wall of the rocker, and the cross member extends outward in the vehicle width direction beyond the said fastening portion. [Effects of the Invention]

[0031] As explained above , book The vehicle understructure according to the invention is, Upper Impact component by It has the excellent effect of effectively absorbing impact energy and suppressing inward bending of the rocker. [Brief explanation of the drawing]

[0035] [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 state of impact load being applied to the vehicle's rocker over time. [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]

[0036] 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 indicated in each figure as appropriate indicate the forward, upward, and right directions of a vehicle to which the vehicle floor structure according to one embodiment of the present invention is applied, respectively. Hereinafter, when simply referring to the front-rear, up-down, and left-right directions, unless otherwise specified, these refer to the front-rear direction of the vehicle, the up-down direction of the vehicle, and the left-right direction when facing forward.

[0037] <First Embodiment> (Vehicle understructure configuration)

[0038] 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.

[0039] 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.

[0040] 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, and on the floor panel 12, between the rockers 14 and 16, along the vehicle width direction. As a cross member A floor cross member (hereinafter simply referred to as "cross member") 18 is spanned across. The cross member 18 is positioned between the bead portions 12A which are arranged along the longitudinal direction of the vehicle.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] Furthermore, a bottom wall portion 24E is provided below the lower inner wall portion 24B, formed in a substantially horizontal direction 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. Fasteners are provided on the bottom wall portion 24E. (Fastening part) The fastener 32 is designed to allow insertion, and the fixing piece 30 provided on the battery pack 20 can be fastened and secured to the rocker 14 via the fastener 32.

[0048] 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 upper part of the rocker 14 (Top of the rocker) 14A and lower (Lower part of the rocker)The area of ​​the closed section differs between 14B and 14B. 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.

[0049] And within the upper closed section 36 of the rocker 14, there is a ladder-shaped shock absorbing section ( Upper A shock-absorbing section 38 is provided, and the 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 side An impact-absorbing section 40 is formed, and the impact-absorbing section 40 is positioned so as to overlap with the battery pack 20 when viewed from the side of the vehicle.

[0050] Now, let's explain the shock-absorbing sections 38 and 40, respectively. The impact-absorbing sections 38 and 40 are integrally formed with the outer section 22 and the inner section 24. The impact-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) connecting walls 38C. 2 The multiple rooms described are formed by multiple connecting walls 38C.

[0051] On the other hand, the impact absorbing section 40 includes an upper wall 40A that spans substantially horizontally (vehicle width direction) between the lower inner wall 24B of the inner section 24 and the outer wall 22A of the outer section 22. Below this upper wall 40A, a lower wall 40B is formed opposite to the upper wall 40A, and the upper wall 40A and the lower wall 40B are spanned vertically by a plurality (in this case, three) connecting walls 40C. 4 The multiple rooms described are formed by multiple connecting walls 40C.

[0052] (Function and effect of the vehicle's understructure) Next, the operation and effects of the vehicle understructure according to this embodiment will be described.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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).

[0057] 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.

[0058] 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.

[0059] 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).

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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).

[0065] 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.

[0066] 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.

[0067] (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.

[0068] 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.

[0069] 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).

[0070] 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.

[0071] <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.

[0072] Furthermore, in this case, when a vehicle is involved in a side collision, the impact load input to the rocker is transmitted to the floor 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 transmitted to the fuel cell.

[0073] 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).

[0074] 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.

[0075] 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.

[0076] (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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] In the case of a gasoline vehicle, 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, so the position of the floor panel 56 in the vertical direction can be set lower. For this reason, the impact absorbing section (first impact absorbing section) 60, which is provided so as to overlap with the cross member 58 installed on top of the floor panel 56 in a side view of the vehicle, is provided on the lower 62A side of the rocker 62.

[0081] 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]

[0082] 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 (floor 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 Shock-absorbing part ( Upper Shock-absorbing part, rocker) 38A Upper wall (side wall) 40 Shock-absorbing part ( lower side Shock-absorbing part, rocker) 42 Rocka 46 Rocka 52 Crossmember 54 Rocka 58 Cross member (floor cross member) 60 Shock-absorbing part ( lower side (Shock absorbing part) 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, 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 portion does not have a vertical wall portion that overlaps the inner wall portion of the vehicle within the closed cross section, and further includes a horizontal wall portion that is provided along the vehicle width direction and connected to the inner wall portion of the vehicle, and the cross member and the horizontal wall portion of the upper impact absorbing portion are connected in the vehicle width direction via the inner wall portion of the vehicle, in a vehicle understructure.

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 side wall portion.

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 comprises 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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