Side sill structure and lower structure of automobile

Abstract

Provided are a side sill structure and a lower structure of an automobile, which can further increase the degree of freedom in setting the shape of an impact absorbing member and can achieve high side impact resistance.　A vehicle body 1 includes a side sill 15 and an impact absorbing member 30. The impact absorbing member 30 is formed of a plurality of members 31, 32. The impact absorbing member 30 includes a hat-shaped part 40 having a first top plate section 41 and a pair of vertical wall sections 45, 46, and a second top plate section 42 that connects the pair of vertical wall sections 45, 46. The second top plate section 42 divides the inner space of the hat-shaped part 40 in the width direction X, whereby a first closed cross section part 61 including the first top plate section 41 and a second closed cross section part 62 adjacent to the first closed cross section part 61 in the width direction X are formed. The impact absorbing member 30 is spaced apart from a side sill outer 21, or is in contact with the side sill outer 21 without being joined to the side sill outer 21.

Description

Side sill structures and vehicle undercarriage

[0001] The present disclosure relates to a side sill structure and an undercarriage of a motor vehicle.

[0002] The body of a passenger car, which is one type of vehicle, typically has a center pillar arranged along the vertical direction of the vehicle body and side sills connected to the lower part of the center pillar and arranged along the longitudinal direction of the vehicle body (see, for example, Patent Documents 1 to 3). When a passenger car is hit in a side collision, the center pillar and the side sills work together to receive the impact load, thereby absorbing the impact and protecting occupants in the vehicle cabin.

[0003] In Patent Document 1, a reinforcing member is disposed within a side sill to effectively absorb impact energy during a side collision. This reinforcing member includes a pair of lateral walls extending in the vehicle width direction and spaced apart from each other in the vehicle up-down direction, a pair of vertical walls spaced apart from each other in the vehicle width direction and connected to the pair of lateral walls, and a plurality of intermediate vertical walls spaced apart from each other in the vehicle width direction and connected to the pair of lateral walls. This reinforcing member is a one-piece molded product made of extruded aluminum.

[0004] The vehicle side sill described in Patent Document 2 includes a side sill frame formed with a hollow portion, a first reinforcement frame disposed in the hollow portion and joined to the side sill frame, and a second reinforcement frame disposed in the hollow portion and joined to the first reinforcement frame and the side sill frame. The first reinforcement frame and the second reinforcement frame are hat members, and are arranged in order from the inside in the vehicle width direction. The second reinforcement frame is joined to the second side sill frame on the outside in the vehicle width direction.

[0005] The vehicle side sill described in Patent Document 3 includes a side sill inner panel, a side sill outer panel joined to the side sill inner panel, and a first buffer member disposed between the panels and constituting a plurality of closed cross sections aligned in the width direction of the side sill. The first buffer member includes a main body formed by bending a single plate material and at least one partition member connecting both side surfaces of the main body. The main body is formed in a hat shape. The top plate of the main body is joined to the side sill outer panel.

[0006] Japanese Patent Application Publication No. 2021-066315 Special Publication No. 2024-524258 Special Publication No. 2023-541988

[0007] In electric vehicles (BEVs), the battery for the electric motor that drives the electric vehicle may be located between the left and right side sills in the lower part of the vehicle body. The battery is housed in a battery box. In the event of a side collision, there is a trend toward higher collision safety performance to protect the battery and to address the increase in collision energy due to the recent increase in battery weight. The trend toward higher collision safety performance is not limited to electric vehicles, but also applies to vehicles that transmit the power of an internal combustion engine directly to the wheels. Therefore, it is desirable to be able to shape the reinforcing member (shock absorbing member) inside the side sill more appropriately depending on the vehicle model, etc.

[0008] However, the reinforcing member described in Patent Document 1 is a one-piece extrusion-molded product, which limits the flexibility of its shape. Furthermore, in Patent Documents 2 and 3, the impact absorbing member disposed within the side sill is joined to the side sill outer. As a result, during a side collision, the impact absorbing member is likely to deform in response to the deformation of the side sill outer. This may prevent the impact absorbing member from deforming as intended when designed, leaving room for improvement in side collision resistance.

[0009] In view of the above problems, one object of the present disclosure is to provide a side sill structure and an automobile lower structure that allow greater freedom in designing the shape of the impact absorbing member and achieve high side collision resistance performance.

[0010] The present disclosure relates to the following side sill structure and automobile undercarriage structure.

[0011] (1) A side sill structure comprising: a side sill including a side sill outer and a side sill inner arranged inward in a vehicle width direction relative to the side sill outer, extending in a vehicle longitudinal direction and forming a closed cross-sectional space in a cross section perpendicular to the vehicle longitudinal direction; and an impact absorbing member formed of a plurality of members, wherein the impact absorbing member includes, in the cross section, a first top plate portion extending in a vehicle height direction and a hat-shaped portion having a pair of vertical wall portions extending along the vehicle width direction from both ends of the first top plate portion in the vehicle height direction, and a second top plate portion arranged at a distance from the first top plate portion in the vehicle width direction and connecting the pair of vertical wall portions, wherein the second top plate portion divides the inner space of the hat-shaped portion in the vehicle width direction, thereby forming a first closed cross-sectional portion including the first top plate portion and a second closed cross-sectional portion adjacent to the first closed cross-sectional portion in the vehicle width direction, and wherein the impact absorbing member is separated from the side sill outer or is in contact with the side sill outer without being joined to it.

[0012] (2) The impact absorbing member is formed by combining a first hat member and a second hat member, wherein a top plate portion of the first hat member forms the first top plate portion, a top plate portion of the second hat member forms the second top plate portion, and a pair of first portions that are a pair of vertical wall portions of the first hat member and a pair of second portions that are a pair of vertical wall portions of the second hat member cooperate to form the pair of vertical wall portions. This is the side sill structure described in (1).

[0013] (3) The side sill structure according to (2), wherein the Vickers hardness of the first hat member is lower than the Vickers hardness of the second hat member.

[0014] (4) The side sill structure according to (2), wherein the Vickers hardness of the first hat member is higher than the Vickers hardness of the second hat member.

[0015] (5) The side sill structure according to any one of (2) to (4), wherein the thickness of the first hat member is smaller than the thickness of the second hat member.

[0016] (6) The side sill structure according to any one of (2) to (4), wherein the plate thickness of the first hat member is greater than the plate thickness of the second hat member.

[0017] (7) The side sill structure according to any one of (2) to (6), wherein the Vickers hardness HV1 and the plate thickness t1 of the first hat member, and the Vickers hardness HV2 and the plate thickness t2 of the second hat member satisfy the following relationships: 180≦HV1, HV2≦780, 0.8 mm≦t1 t2≦2.3 mm, and HV1×t1<HV2×t2.

[0018] (8) The side sill structure described in (1), wherein the impact absorbing member includes a hat member that forms the hat-shaped portion and a top plate member that forms the second top plate portion.

[0019] (9) A side sill structure as described in (8), wherein the Vickers hardness HV2 and plate thickness t2 of the hat member and the Vickers hardness HV1 and plate thickness t1 of the top plate member satisfy the following relationships: 180≦HV1, HV2≦780, 0.8mm≦t1 t2≦2.3mm, and HV1×t1<HV2×t2.

[0020] (10) A side sill structure described in any one of (1) to (9), wherein the second top plate portion of the impact absorbing member has a shape that is convex toward the first top plate portion in the cross section.

[0021] (11) The side sill structure according to any one of (1) to (10), wherein the impact absorbing member is made of a steel plate.

[0022] (12) The side sill structure according to any one of (1) to (11), wherein the hat-shaped portion has a pair of flanges extending from the pair of vertical wall portions, and the pair of flanges are joined to the side sill inner.

[0023] (13) The side sill structure according to any one of (1) to (12), wherein a bead is formed on the impact absorbing member.

[0024] (14) A side sill structure described in any one of (1) to (13), wherein the impact absorbing member is supported by the side sill within the closed cross-sectional space or is arranged to the side of the side sill in the vehicle width direction.

[0025] (15) The side sill structure described in any one of (2) to (7), wherein the first hat member includes a pair of first flanges, a pair of first vertical wall portions extending from the pair of first flanges, and the first top plate portion connecting the pair of first vertical wall portions; and the second hat member includes a pair of second flanges, a pair of second vertical wall portions extending from the pair of second flanges, and the second top plate portion connecting the pair of second vertical wall portions and joined to the pair of first flanges.

[0026] (16) The side sill structure according to any one of (2) to (7) and (15), further comprising a reinforcing member in at least one of the hat members.

[0027] (17) The side sill structure according to any one of (2) to (7) and (15) to (16), wherein the impact absorbing member further has an nth hat member (n is a natural number of 3 or more) formed in a hat shape in the cross section, the nth hat member including a pair of nth flanges, a pair of nth vertical wall portions extending from the pair of nth flanges, and an nth top plate portion connecting the pair of nth vertical wall portions, the hat members being aligned along the vehicle width direction, and the top plate portion and the pair of flanges being joined to each other in the hat members adjacent to each other.

[0028] (18) The side sill structure according to any one of (1) to (17), wherein the impact absorbing member is made of a steel plate.

[0029] (19) An undercarriage of an automobile comprising the side sill structure described in any one of (1) to (18), wherein the side sills are provided in pairs spaced apart in the vehicle width direction, and further comprising a plurality of cross members disposed between the pair of side sills and extending in the vehicle width direction, and the impact absorbing member is provided inside each of the pair of side sills or on the inside in the vehicle width direction.

[0030] (20) The undercarriage of the automobile according to (19), further comprising a battery case disposed below the cross member and accommodating a battery.

[0031] According to the present disclosure, the degree of freedom in designing the shape of the impact absorbing member can be increased, and high side collision resistance performance can be achieved.

[0032] FIG. 1 is an exploded perspective view showing a portion of a vehicle body provided with a lower structure including a side sill structure according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view of the lower structure taken along line II-II in FIG. 1. FIG. 3 is a schematic cross-sectional view showing a main portion of a first modified example of the first embodiment of the present disclosure. FIG. 4 is a schematic perspective view showing a main portion of a third modified example of the first embodiment of the present disclosure. FIG. 5 is a cross-sectional view showing a main portion of a fourth modified example of the first embodiment of the present disclosure. FIG. 6 is a cross-sectional view showing a main portion of a fifth modified example of the first embodiment of the present disclosure. FIG. 7 is a cross-sectional view showing a main portion of another modified example of the first embodiment of the present disclosure. FIG. 8 is an exploded perspective view showing a portion of a vehicle body provided with a lower structure including a side sill structure according to a second embodiment of the present disclosure. FIG. 9 is a cross-sectional view of the lower structure taken along line IX-IX in FIG. 8. FIG. 10 is a schematic cross-sectional view showing a main portion of a first modified example of the second embodiment of the present disclosure. FIG. 11 is a schematic cross-sectional view showing a main portion of a second modified example of the second embodiment of the present disclosure. FIG. 12 is a schematic cross-sectional view showing a main portion of a third modified example of the second embodiment of the present disclosure. FIG. 13 is a schematic cross-sectional view showing a main portion of a fourth modified example of the second embodiment of the present disclosure. FIG. 14 is a schematic cross-sectional view showing a main portion of a fifth modified example of the second embodiment of the present disclosure. FIG. 15 is a drawing of a modified example of the fifth modified example of the second embodiment of the present disclosure. FIG. 16 is a schematic cross-sectional view showing a main portion of a sixth modified example of the second embodiment of the present disclosure. FIG. 17 is a diagram showing a modified example of the sixth modified example of the second embodiment of the present disclosure. FIG. 18 is a schematic cross-sectional view showing a main portion of a seventh modified example of the second embodiment of the present disclosure. FIG. 19 is a schematic cross-sectional view showing a main portion of an eighth modified example of the second embodiment of the present disclosure. FIG. 20 is a schematic cross-sectional view showing a main portion of a ninth modified example of the second embodiment of the present disclosure. FIG. 21 is a schematic cross-sectional view showing a main portion of a tenth modified example of the second embodiment of the present disclosure. FIG. 22 is a schematic cross-sectional view showing a main portion of an eleventh modified example of the second embodiment of the present disclosure. Fig. 23 is a diagram for explaining a modification of the eleventh modification of the second embodiment. Fig. 24 is a schematic cross-sectional view showing a main part of a twelfth modification of the second embodiment of the present disclosure. Fig. 25 is a schematic cross-sectional view showing a main part of a fourteenth modification of the second embodiment of the present disclosure.FIG. 26 is a schematic perspective view showing a main part of a fourteenth modified example of the second embodiment of the present disclosure.

[0033] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In this embodiment, a vehicle body structure applied to an automobile will be described.

[0034] [First Embodiment] (Vehicle Body) FIG. 1 is an exploded perspective view showing a portion of an automobile body 1 equipped with an undercarriage 2 including a side sill structure 14 according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view of the undercarriage 2 taken along line II-II in FIG. 1. Note that FIG. 2 shows a state in which a battery case 100 is fixed to the undercarriage 2, and the back side of the cross section is not shown. In this specification, the direction along the traveling direction of the vehicle body 1 (vehicle) is referred to as the longitudinal direction Y of the vehicle body, the traveling direction of the vehicle body is referred to as the front, and the opposite side is referred to as the rear, the up-down direction of the vehicle body is referred to as the height direction Z, and the direction perpendicular to the longitudinal direction Y and the height direction Z is referred to as the width direction X of the vehicle body. In addition, in the width direction X, the direction away from the center of the vehicle body 1 is referred to as the outside, and the opposite direction is referred to as the inside.

[0035] As shown in Figures 1 and 2, the vehicle body 1 is a part of a vehicle, and an example of the vehicle is an automobile. An example of an automobile is a passenger car. Examples of the passenger car include a sedan, a coupe, a hatchback, a minivan, and an SUV (Sport Utility Vehicle). The vehicle is, for example, an electric vehicle (Battery Electric Vehicle) or a hybrid vehicle (HV, Hybrid Vehicle) including a plug-in hybrid vehicle, and the drive wheels can be driven by electric power from a battery 101 installed under the vehicle body 1.

[0036] The vehicle body 1 includes a frame 10 and a battery case 100.

[0037] The frame 10 includes a front pillar 11 , a roof pillar 12 , a center pillar 13 , a side sill structure 14 including a side sill 15 , floor cross members 16 and 17 , and a floor panel 18 .

[0038] A pair of side sill structures 14 including a front pillar 11, a roof pillar 12, a center pillar 13, and a side sill 15 are provided spaced apart in the width direction X.

[0039] The front pillar 11 has an upper pillar 11a that extends upward and is connected to the roof pillar 12 toward the rear, and a lower pillar 11b that is disposed below the upper pillar 11a.

[0040] The roof pillar 12 is disposed on the roof portion of the vehicle body 1 and extends rearward from the pillar upper 11a.

[0041] The center pillar 13 is disposed along the height direction Z and connects the roof pillar 12 and the side sill 15 .

[0042] The side sill 15 is provided at the lower part of the outer portion of the vehicle body 1 in the width direction X. The side sill 15 is connected to the lower part of the center pillar 13 and is disposed along the front-rear direction Y of the vehicle body 1. The side sill 15 has a closed cross-sectional shape in a cross section perpendicular to the front-rear direction Y.

[0043] The floor cross members 16, 17 are members extending in the width direction X, and are disposed between a pair of left and right side sills 15, 15 to connect these side sills 15, 15. The floor cross members 16, 17 are disposed on the front seat side of the vehicle interior (cabin) formed by the vehicle body 1. The floor cross members 16, 17 are disposed spaced apart in the fore-and-aft direction Y, with the floor cross member 17 disposed behind the floor cross member 16. The floor cross members 16, 17 each have a hat-shaped cross section perpendicular to the width direction X, and form a closed cross-sectional shape in cooperation with a floor panel 18. The floor panel 18 forms the bottom of the cabin of the vehicle body 1 and is fixed to the floor cross members 16, 17.

[0044] Slide rails (not shown) are installed on the floor cross members 16 and 17. The slide rails support seats (not shown) on which passengers sit.

[0045] A plate-shaped floor panel 18 is installed below the floor cross members 16, 17. A battery case 100 is installed below the floor panel 18. The battery case 100 houses a battery 101, which may be a lithium-ion battery or the like.

[0046] The side sill 15 is located outward of the battery 101 in the width direction X to protect the battery 101 from a side collision with a utility pole or the like (pole side collision). The side sill 15 extends along the front-rear direction Y. The battery case 100 is fixed to the side sill 15. In this embodiment, a widthwise end 100a of the battery case 100 is fixed to, for example, a lower wall 224 of a side sill inner panel 22 (described later) of the side sill 15. A side wall 100b rising upward from the widthwise end 100a of the battery case 100 is formed in an intermediate portion of the battery case 100 in the width direction X as a protective wall for the battery 101. The battery 101 is disposed inward of the side wall 100b in the width direction X. A gap A is formed between the side wall 100b and the side sill inner panel 22. The gap A varies depending on the vehicle model, but can be, for example, a value of several millimeters to several tens of millimeters.

[0047] (Side Sill Structure) When describing the side sill structure 14, unless otherwise specified, the configuration will be described in a cross section perpendicular to the front-rear direction Y. A pair of side sill structures 14 are provided spaced apart in the width direction X.

[0048] Each side sill structure 14 includes the above-described side sill 15 and an impact absorbing member 30 .

[0049] The side sill 15 includes a side sill outer 21 and a side sill inner 22 disposed on the inside of the side sill outer 21 in the width direction X.

[0050] The side sill outer 21 and the side sill inner 22 are each formed in a hat shape and cooperate to form a closed cross-sectional space 23 in the side sill 15 .

[0051] The side sill outer 21 has a shape that opens inward in the width direction X, and the side sill inner 22 has a shape that opens outward in the width direction X. The side sill outer 21 and the side sill inner 22 are fixed to each other by joining means such as welding or fastening members with their flanges 211, 221; 215, 225 abutting against each other. In this embodiment, the side sill outer 21 and the side sill inner 22 are joined to each other by, for example, welding. Various welding methods can be used, such as spot welding, TIG welding, arc welding, laser welding, and plasma welding. The same applies to the welding methods used to join other parts.

[0052] More specifically, the side sill outer 21 has an upper flange 211, an upper wall 212 extending outward from the upper flange 211 in the width direction X, a side wall 213 extending downward from the upper wall 212, a lower wall 214 extending inward from the side wall 213 in the width direction X, and a lower flange 215 extending downward from the lower wall 214.

[0053] The side sill inner 22 has an upper flange 221, an upper wall 222 extending inward in the width direction X from the upper flange 221, a side wall 223 extending downward from the upper wall 222 and joined to the floor cross members 16, 17, a lower wall 224 extending outward from the side wall 223 in the width direction X, and a lower flange 225 extending downward from the lower wall 224.

[0054] The upper flanges 211 and 221 are joined to each other by the joining method described above, and similarly, the lower flanges 215 and 225 are joined to each other by the joining method described above.

[0055] The upper wall 212 and the lower wall 214 of the side sill outer 21 are inclined so that the distance between them in the height direction Z narrows as they move outward in the width direction X. In this embodiment, the inclination angles of the upper wall 212 and the lower wall 214 with respect to the horizontal plane are greater than the inclination angles of the upper wall 222 and the lower wall 224 of the side sill inner 22 with respect to the horizontal plane. Furthermore, in this embodiment, the length of the side sill outer 21 in the width direction X is greater than the length of the side sill inner 22 in the width direction X. With this configuration, the space on the side sill outer 21 side is larger than the length of the side sill inner 22 in the width direction X in the closed cross-sectional space 23. Furthermore, in this embodiment, the length of the side wall 213 of the side sill outer 21 in the height direction Z is less than the length of the side wall 223 of the side sill inner 22 in the height direction Z. With this configuration, the side sill 15 forms a closed cross-sectional space 23 that protrudes outward in the width direction X.

[0056] The side sill 15 may have a shape that is symmetrical in the width direction X, and the specific shape is not limited.

[0057] (Major Configuration of Impact Absorbing Member) The impact absorbing member 30 plastically deforms in cooperation with the side sill 15 during a side collision, thereby absorbing the impact energy of the side collision.

[0058] The impact absorbing member 30 is formed of a plurality of members (in this embodiment, a first hat member 31 and a second hat member 32).

[0059] The impact absorbing member 30 comprises a hat-shaped portion 40 having a first top plate portion 41 extending in the height direction Z, and a pair of vertical wall portions 45, 46 extending from both ends of the first top plate portion 41 in the height direction Z along the width direction X, and a second top plate portion 42 arranged at a distance from the first top plate portion 41 in the width direction X and connecting the pair of vertical wall portions 45, 46.

[0060] The second top plate portion 42 divides the inner space of the hat-shaped portion 40 in the width direction X, thereby forming a first closed cross-sectional portion 61 including the first top plate portion 41 and a second closed cross-sectional portion 62 adjacent to the first closed cross-sectional portion 61 in the width direction X. The impact absorbing member 30 is spaced apart from the side sill outer 21, or is in contact with the side sill outer 21 without being joined thereto.

[0061] (Effects of Main Configuration of Impact Absorbing Member) Because the impact absorbing member 30 has the above-described configuration, it is possible to set the timing at which the first closed cross-sectional portion 61 and the second closed cross-sectional portion 62 start to deform and the manner in which they deform during a side collision. This makes it possible to set the impact absorbing behavior of the impact absorbing member 30 during a side collision depending on the characteristics of the vehicle (such as the presence or absence of the battery case 100 and the layout of the battery case 100). This allows the vehicle to achieve higher side collision resistance performance. Moreover, because the impact absorbing member 30 is formed from multiple members (in this embodiment, the first hat member 31 and the second hat member 32), there is a greater degree of freedom in designing the shape compared to when the impact absorbing member 30 is formed from a single member.

[0062] (Detailed Configuration Example of Impact Absorbing Member) The impact absorbing member 30 has multiple closed cross-sectional portions (two closed cross-sectional portions 61, 62 in this embodiment) in the width direction X. In this manner, the multiple closed cross-sectional portions 61, 62 are gradually crushed during a side collision, thereby absorbing more impact energy. The impact absorbing member 30 is also formed by combining multiple members (two hat members 31, 32 in this embodiment). By combining the strengths (tensile strengths) and thicknesses of the members 31, 32, the crushing characteristics of each closed cross-sectional portion 61, 62 can be adjusted to a desired state. For example, one hat member 31 may crush relatively more during a side collision to absorb impact, while the other hat member 32 may crush relatively less during a side collision to suppress the amount of intrusion of the side sill 15 or the like into the widthwise inward direction during a side collision.

[0063] In this embodiment, the impact absorbing member 30 is formed in a uniform shape in the front-rear direction Y over the entire area of ​​the impact absorbing member 30, but the shape may be different at each portion in the front-rear direction Y. In this embodiment, the impact absorbing member 30 is formed in a shape that is convex outward in the width direction X, but may be formed in a shape that is convex inward in the width direction X (a shape that is symmetrical in the width direction X to the shape shown in FIG. 2 ). The impact absorbing member 30 may be installed over the entire area where the side sill 15 is arranged in the front-rear direction Y, or may be installed in part of the area. In this embodiment, the impact absorbing member 30 is arranged continuously from the front end 15a to the rear end 15b of the side sill 15.

[0064] The impact absorbing member 30 is preferably disposed at least in a location facing the floor cross members 16, 17 in the width direction X. This configuration allows the impact from the impact absorbing member 30 to be efficiently transmitted to the floor cross members 16, 17 during a side collision. This prevents the impact absorbing member 30 from pushing the battery case 100 through the side sill inner 22. This further improves the ability to protect the battery case 100. In this embodiment, the impact absorbing member 30 is formed in a vertically symmetrical shape, but it may also be vertically asymmetrical. Because the impact absorbing member 30 is formed from multiple components, it is easy to manufacture the impact absorbing member 30 in either a vertically symmetrical or vertically asymmetrical shape.

[0065] In this embodiment, the impact absorbing member 30 is supported by the side sill 15 within the closed cross-sectional space 23 of the side sill 15. Specifically, the impact absorbing member 30 is disposed between the side wall 213 of the side sill outer panel 21 and the side wall 223 of the side sill inner panel 22. In this embodiment, the impact absorbing member 30 has a tapered shape in which the length in the height direction Z decreases toward the outside in the width direction X. The impact absorbing member 30 is elongated in the width direction X, and the length in the width direction X is greater than the length in the height direction Z.

[0066] The first top plate portion 41 suppresses out-of-plane deformation of the pair of vertical wall portions 45, 46 connected to the first top plate portion 41. Furthermore, the first top plate portion 41 is the portion of the impact absorbing member 30 that is first subjected to an impact load during a side collision.

[0067] In this embodiment, the first top plate portion 41 is adjacent to the side wall 213 of the side sill outer 21 , but it is preferable that it be spaced apart from the side sill outer 21 .

[0068] With this preferred configuration, the work of installing the impact absorbing member 30 inside the side sill 15 is easy. This is because the work of joining the first top plate portion 41 to the side wall 213 of the side sill outer 21 is not necessary. If the first top plate portion 41 were to be joined to the side wall 213 of the side sill outer 21 by welding, a welding machine would need to be sandwiched between the first top plate portion 41 and the side wall 213. This makes the work of installing the impact absorbing member 30 inside the side sill 15 time-consuming. This kind of time-consuming work is present whether the type of welding is spot welding, laser welding, or adhesive bonding.

[0069] Furthermore, with this preferred configuration, in the event of a side collision of the vehicle, the impact absorbing member 30 can undergo two-stage collapse by sequentially collapsing the two closed cross-sectional portions 61, 62 while the influence of the side sill outer 21 is reduced, thereby increasing the efficiency of absorbing impact energy. In other words, in the event of a side collision of the vehicle, the impact absorbing member 30 can deform and absorb impact while being less affected by the deformation of the side sill outer 21. This allows the impact absorbing performance of the impact absorbing member 30 to be exhibited more effectively.

[0070] Furthermore, with this preferred configuration, deformation of the components due to impact transmission from the side sill outer 21 to the impact absorbing member 30 and the side sill inner 22 can be suppressed when a relatively mild side collision occurs to the vehicle. When a relatively mild side collision occurs to the vehicle, impact acts on the side sill outer 21, but the amount of impact transmitted from the side sill outer 21 to the impact absorbing member 30 is small. Therefore, the amount of impact transmitted to the side sill inner 22 via the impact absorbing member 30 can be reduced. In this case, the amount of deformation of the side sill 15 can be reduced, thereby suppressing a decrease in the vehicle's driving performance (straight-line running performance, etc.). Furthermore, when repairing a vehicle, while the side wall 213 of the side sill outer 21 and the like must be repaired, repairs to the impact absorbing member 30 and the side sill inner 22 are not required, thereby reducing the effort and cost required for vehicle maintenance. On the other hand, when a large side collision occurs to the vehicle, the impact is transmitted from the side sill outer 21 to the side sill inner 22 via the impact absorbing member 30, thereby enabling efficient absorption of impact energy through deformation of the impact absorbing member 30 and the side sill inner 22.

[0071] Furthermore, with such a preferable configuration, vibration noise caused by contact between the first top plate portion 41 and the side sill outer 21 can be suppressed, and the impact load from the side sill outer 21 during a side collision can be transmitted to the impact absorbing member 30 along with the crushing of the side sill outer 21. It is preferable that the first top plate portion 41 is arranged parallel to this side wall 213, since the impact load from the side wall 213 of the side sill outer 21 is received by the entire first top plate portion 41.

[0072] In this embodiment, the first top plate portion 41 is the portion of the impact absorbing member 30 that has the shortest length in the height direction Z. The boundaries between the first top plate portion 41 and each of the vertical wall portions 45, 46 are formed in a curved shape.

[0073] The pair of vertical wall portions 45, 46 are arranged along the width direction X, and the distance between the pair of vertical wall portions 45, 46 increases toward the side sill inner 22. This layout of the pair of vertical wall portions 45, 46 allows the upper and lower portions of the impact absorbing member 30 to bear the impact load acting inward in the width direction X from the side sill outer 21 in a balanced manner. This increases the amount of impact energy absorbed by the impact absorbing member 30 during a side collision. The pair of vertical wall portions 45, 46 may also be arranged parallel (horizontal) to the width direction X.

[0074] The first top plate portion 41 is connected to the distal ends of each of the pair of vertical wall portions 45, 46 in the width direction X, while flanges 47, 48 are connected to the proximal ends of the pair of vertical wall portions 45, 46.

[0075] The flanges 47, 48 are provided on the hat-shaped portion 40 and extend from the pair of vertical wall portions 45, 46. The flanges 47, 48 are portions to be joined to the side sill 15, and in this embodiment, are joined to the inner surface of the side sill inner panel 22 by the joining method described above. The flanges 47, 48 do not have to be joined directly to the side sill inner panel 22, but may be joined to the side sill inner panel 22 via another member.

[0076] In this way, the pair of flanges 47, 48 of the hat-shaped portion 40 are joined to the side sill inner panel 22. With this configuration, during a side collision, the impact load acting on the first top panel portion 41 can be transmitted with high transmission efficiency from the side sill inner panel 22 to the floor cross members 16, 17. Therefore, the side sill 15, the impact absorbing member 30, and the floor cross members 16, 17 work together to absorb more impact energy. As a result, collision of the side sill 15 with the battery case 100 during a side collision can be reduced.

[0077] The flange 47 extends upward from the upper vertical wall portion 45, and the flange 48 extends downward from the lower vertical wall portion 46. In the hat-shaped portion 40, these flanges 47, 48 are spaced apart from each other, and the hat-shaped portion 40 has a shape in which the inner side in the width direction X is open toward the side sill inner 22. In this manner, the impact absorbing member 30 is joined to the side sill 15 only by the flanges 47, 48, and it is preferable that no other portion of the impact absorbing member 30 is disposed between the flanges 47, 48 in the height direction Z. This configuration can further reduce the weight of the impact absorbing member 30. Furthermore, when spot welding the side sill inner 22 and the impact absorbing member 30, the flanges 47, 48, which are disposed outward in the height direction Z relative to the pair of vertical wall portions 45, 46, can be welded to the side sill inner 22 by clamping them with a welding machine. Thus, in this embodiment, the outward flanges 47, 48 are disposed outward in the height direction Z relative to the pair of vertical wall portions 45, 46.

[0078] Instead of the flanges 47, 48, it is possible to provide an inward flange between the base ends of the pair of vertical wall portions 45, 46, positioned inward in the height direction Z relative to the pair of vertical wall portions 45, 46. In this case, the inward flange has a portion extending downward from the base end of the vertical wall portion 45 and a portion extending upward from the base end of the vertical wall portion 46. These portions are integrally formed, thereby providing a plate-like portion (a single inward flange) between the base ends of the vertical wall portions 45, 46. If this plate-like portion were to be joined to the side sill inner panel 22, it would be difficult to clamp the plate-like portion and the side sill inner panel 22 with a welding machine. Therefore, the plate-like member and the side sill inner panel 22 would need to be joined using an additional material, such as an adhesive, which would reduce the flexibility in designing the joining method between the impact absorbing member and the side sill inner panel 22.

[0079] Furthermore, as in this embodiment, the flanges 47, 48 of the impact absorbing member 30 are preferably joined to the side wall 223 of the side sill inner panel 22, rather than being disposed between the flanges 211, 221 and between the flanges 215, 225 of the side sill 15. This preferred configuration eliminates the need to sandwich the flanges 47, 48 of the impact absorbing member 30 between the flanges 211, 221; 215, 225 of the side sill 15, eliminating the need for the difficult alignment work of welding three or more plate-shaped members to join the impact absorbing member 30. Furthermore, the flanges 211, 221; 215, 225 may not be provided near the front end 15a, the center pillar 13, or the rear end 15b of the side sill 15. Even in such cases, the flanges 47, 48 of the impact absorbing member 30 can be joined to the side sill 15 near the front end 15a, the center pillar 13, or the rear end 15b of the side sill 15.

[0080] The second top plate portion 42 suppresses out-of-plane deformation such as causing the pair of vertical wall portions 45, 46 connected to the second top plate portion 42 to collapse toward the inside of these vertical wall portions 45, 46. The second top plate portion 42 is disposed between the inner surfaces of the pair of vertical wall portions 45, 46. The second top plate portion 42 is disposed parallel to the first top plate portion 41.

[0081] The second top plate portion 42 is disposed at an intermediate portion between the pair of vertical wall portions 45, 46 in the rising direction (width direction X) of the pair of vertical wall portions 45, 46. With this configuration, the pair of vertical wall portions 45, 46 can be separated by the second top plate portion 42. That is, in the width direction X, the vehicle outer and inner portions of each vertical wall portion 45, 46 can be shortened relative to the second top plate portion 42. As a result, out-of-plane deformation of the pair of vertical wall portions 45, 46 during a side collision can be suppressed, and the amount of energy absorption by wall buckling can be increased.

[0082] In the present embodiment, the second top plate portion 42 is disposed closer to the side sill outer 21 than the side sill outer 21 or the side sill inner 22. As a result, the length from the first top plate portion 41 to the second top plate portion 42 in the width direction X is shorter than the length from the second top plate portion 42 to the side wall 223 of the side sill inner 22. In particular, in the present embodiment, the second top plate portion 42 is located outside in the width direction X with respect to the flanges 211, 221; 215, 225, which are the boundaries between the side sill outer 21 and the side sill inner 22 in the width direction X.

[0083] In this manner, the second top plate portion 42 is disposed closer to the side sill outer portion 21 than the side sill outer portion 21 and the side sill inner portion 22. This reduces the space between the first top plate portion 41 and the second top plate portion 42 (the space within the first hat member 31). As a result, during a side collision, out-of-plane deformation of the portion of the pair of vertical wall portions 45, 46 between the first top plate portion 41 and the second top plate portion 42 (the first portions 45a, 46a of the pair of vertical wall portions 45, 46) can be suppressed. Furthermore, during a side collision, the first closed cross-sectional portion 61 is crushed first, and then the second closed cross-sectional portion 62 is crushed, thereby absorbing the impact load from the width direction X in order, starting with the components disposed on the outer side in the width direction X. This smooth impact absorption operation increases the efficiency with which the impact energy is absorbed by the impact absorbing member 30.

[0084] With the above-described configuration, the first closed cross-sectional portion 61 is formed by the first top plate portion 41, first portions 45a, 46a which are distal end portions of the pair of vertical wall portions 45, 46, and the second top plate portion 42. The second closed cross-sectional portion 62 is formed by the second top plate portion 42, second portions 45b, 46b which are proximal end portions of the pair of vertical wall portions 45, 46, the pair of flanges 47, 48, and the side wall 223 of the side sill inner 22.

[0085] In this embodiment, the impact absorbing member 30 is formed by combining a first hat member 31 and a second hat member 32 .

[0086] Both the first hat member 31 and the second hat member 32 are hat-shaped. The first hat member 31 includes a first top plate 41, first portions 45a, 46a of a pair of vertical wall portions 45, 46, and flanges 49, 50 formed on the first portions 45a, 46a. The second hat member 32 includes a second top plate 42, second portions 45b, 46b of the pair of vertical wall portions 45, 46, and flanges 47, 48.

[0087] The top plate portion of the first hat member 31 forms the first top plate portion 41, and the top plate portion of the second hat member 32 forms the second top plate portion 42. A pair of first portions 45a, 46a, which are a pair of vertical wall portions of the first hat member 31, and a pair of second portions 45b, 46b, which are a pair of vertical wall portions of the second hat member, cooperate to form a pair of vertical wall portions 45, 46 of the impact absorbing member 30. That is, the vertical wall portion 45 is formed by the first portion 45a and the second portion 45b, and the vertical wall portion 46 is formed by the first portion 46a and the second portion 46b.

[0088] In this way, the impact absorbing member 30 is formed by the two hat members 31, 32. With this configuration, the impact absorbing member 30 can be formed with a relatively simple configuration of combining the two hat members 31, 32. Furthermore, the degree of freedom in setting the shape of each of the two hat members 31, 32 can be increased, resulting in a high degree of freedom in setting the shape of the impact absorbing member 30. Furthermore, the deformation mode of the first hat member 31 and the deformation mode of the second hat member 32 during a side collision can be made different, further increasing the degree of freedom in setting the impact absorbing operation of the impact absorbing member 30.

[0089] In this embodiment, each of the first portions 45a, 46a of the first hat component 31 is aligned in a straight line with the corresponding second portions 45b, 46b of the second hat component 32. In this case, "aligned in a straight line" means that the first portions 45a, 46a and the corresponding second portions 45b, 46b are overlapped with each other, resulting in a step corresponding to the thickness of the first portions 45a, 46a, but the first portions 45a, 46a are aligned in a substantially straight line.

[0090] This linear layout allows the impact load acting on the impact absorbing member 30 from the first top panel portion 41 to be transmitted with high transmission efficiency from the side sill inner panel 22 to the floor cross members 16, 17 during a side collision. Therefore, the side sill 15, the impact absorbing member 30, and the floor cross members 16, 17 work together to absorb more impact energy. As a result, the side sill 15 can be prevented from colliding with the battery case 100.

[0091] In this embodiment, the base ends of the first portions 45 a, 46 a in the width direction X are flanges 49, 50, which are joined to the tip ends of the second portions 45 b, 46 b. In this embodiment, the first portions 45 a, 46 a including the flanges 49, 50 are each formed linearly, and the inner surfaces of the flanges 49, 50 are joined to the outer surfaces of the second portions 45 b, 46 b. The flanges 49, 50 of the first portions 45 a, 46 a and the second portions 45 b, 46 b are joined so that the first hat member 31 does not come off the second hat member 32 even when a designed impact load is applied to the impact absorbing member 30.

[0092] In this way, the inner surfaces of the pair of first portions 45 a, 46 a of the first hat component 31 are joined to the outer surfaces of the pair of second portions 45 b, 46 b of the second hat component 32. This makes it possible to realize a configuration in which each of the first portions 45 a, 46 a and the corresponding second portions 45 b, 46 b are arranged in a straight line.

[0093] The length H1 of the first closed cross-sectional portion 61 in the width direction X is smaller than the length H2 of the second closed cross-sectional portion 62 in the width direction X (H2>H1). The ratio H1 / H2 of these lengths is preferably 1 / 3 to 1 / 2. If the ratio H1 / H2 is within the above range, in the event of a side collision, there is no extreme imbalance between the impact absorption effect produced by the crushing of the first hat component 31 and the impact absorption effect produced by the crushing of the second hat component 32, and the impact absorption efficiency of the impact absorbing member 30 as a whole can be increased.

[0094] Regarding the relationship between the length H1 of the first closed cross-section portion 61 in the width direction X and the thickness t1 of the first hat member 31, the smaller the ratio H1 / t1, the more effectively out-of-plane deformation of the first hat member 31 during a side collision is suppressed. Similarly, regarding the relationship between the length H2 of the second closed cross-section portion 62 in the width direction X and the thickness t2 of the second hat member 32, the smaller the ratio H2 / t2, the more effectively out-of-plane deformation of the second hat member 32 during a side collision is suppressed.

[0095] Next, the material and the like of the impact absorbing member 30 will be described.

[0096] The impact absorbing member 30 is preferably formed from a steel plate. If the impact absorbing member is made of aluminum, for example, and the aluminum material is installed inside a steel side sill, galvanic corrosion (bimetallic corrosion) occurs due to contact between aluminum and iron, which are dissimilar metals. Therefore, it is necessary to take measures against galvanic corrosion (rust prevention treatment). On the other hand, if the impact absorbing member 30 is made of steel, the above-mentioned electrical decoration measures are not necessary, and iron, which has a relatively low unit price compared to aluminum, which has a relatively high unit price, can be used, thereby reducing the manufacturing cost of the vehicle body 1.

[0097] In this embodiment, the first hat member 31 and the second hat member 32 of the impact absorbing member 30 are each formed of a steel plate. The tensile strength of each hat member 31, 32 can be, for example, 780 MPa to 2.5 GPa, or 590 MPa to 2.5 GPa. The lower limit of the tensile strength of each hat member 31, 32 can be 980 MPa, 1.3 GPa, 1.5 GPa, 1.7 GPa, 2.0 GPa, or 2.3 GPa. The upper limit of the tensile strength of each hat member 31, 32 can be 1.5 GPa, 1.7 GPa, 2.0 GPa, or 2.3 GPa.

[0098] The tensile strength can be evaluated in accordance with JIS Z 2241:2011. An example of a test piece for measuring the tensile strength is the No. 5 test piece of JIS Z 2241:2011. The tensile test piece can be taken, for example, from the center portions of the pair of vertical wall portions 45, 46 of each hat member 31, 32.

[0099] The Vickers hardness of each of the hat members 31, 32 can be given as an example of the Vickers hardness corresponding to the tensile strength of each of the hat members 31, 32. Examples of the Vickers hardness HV1 and HV2 of each of the hat members 31, 32 are 240 to 780. The lower limit of the Vickers hardness HV1 and HV2 of each of the hat members 31, 32 may be 180 corresponding to 590 MPa, 240 corresponding to 780 MPa, 300 corresponding to 980 MPa, 400 corresponding to 1.3 GPa, 460 corresponding to 1.5 GPa, 520 corresponding to 1.7 GPa, 620 corresponding to 2.0 GPa, or 710 corresponding to 2.3 GPa. In addition, the upper limit of the Vickers hardness HV1, HV2 of each hat member 31, 32 may be 460 corresponding to 1.5 GPa, 520 corresponding to 1.7 GPa, 620 corresponding to 2.0 GPa, 710 corresponding to 2.3 GPa, or 780 corresponding to 2.5 GPa.

[0100] The Vickers hardness of each hat member 31, 32 can be measured as follows. Vickers hardness (HV1) "HV1" refers to the "hardness symbol" when a Vickers hardness test is conducted with a test force of 1 kgf (9.807 N) (JIS Z 2244-1:2020). The Vickers hardness is measured as follows. First, a measurement sample is cut out from a flat portion of the first hat member 31, such as the first top plate portion 41, so that the cut surface (measurement surface) is parallel to the thickness direction of the flat portion. The sample is then embedded in resin and the cut surface is polished. Ten measurements are then taken at 1 / 4 of the plate thickness depth from the surface of the measurement sample on the cut surface (measurement surface) at 0.5 mm intervals with a test force of 1 kgf (9.807 N), and the average is calculated.

[0101] Vickers hardness (HV2) "HV2" is a value obtained by cutting a measurement sample from a flat portion such as the second top plate portion 42 of the second hat member 32 instead of the first top plate portion 41 and performing the above-mentioned test.

[0102] In this embodiment, the tensile strength TS1 (Vickers hardness HV1) of the first hat member 31 is set lower than the tensile strength TS2 (Vickers hardness HV2) of the second hat member 32. In other words, the strength of the side sill outer 21 side of the impact absorbing member 30 is set lower than the strength of the side sill inner 22 side. With this configuration, the strength of the first top plate portion 41 is set lower than the strength of the second top plate portion 42.

[0103] By setting the tensile strength (Vickers hardness) in this manner, during a side collision, the first hat member 31 begins to deform before the second hat member 32, allowing it to absorb impact energy. In the closed cross-sectional space 23, the first hat member 31, which is located farther from the battery case 100, deforms first, postponing the deformation timing of the second hat member 32, which is closer to the battery case 100. In other words, deformation of the second hat member 32 can be suppressed until the first hat member 31 is sufficiently deformed. This increases the amount of impact energy absorbed by the crushing of the first hat member 31, and prevents the side sill inner 22, which crushes together with the crushing of the second hat member 32, from contacting the side wall 100b of the battery case 100. Furthermore, because the second hat member 32 has high strength, the amount of impact energy absorbed by the second hat member 32 can be increased.

[0104] The tensile strength TS2 (Vickers hardness HV2) of the second hat component 32 is preferably approximately 1.3 to 1.7 times the tensile strength TS1 (Vickers hardness HV1) of the first hat component 31, and approximately 1.5 times is an example. By setting the tensile strength TS2 in this manner, the first hat component 31 is crushed during a side collision, and the second hat component 32 begins to crush after the first hat component 31 has been sufficiently crushed. This also prevents cracks from occurring in the first hat component 31, which is severely crushed during a side collision, and thus reduces the impact energy absorption efficiency. A more specific example of the tensile strengths is a configuration in which the tensile strength TS1 of the first hat component 31 is 980 MPa and the tensile strength TS2 of the second hat component 32 is 1.5 GPa. This configuration allows for a higher impact energy absorption value than if the tensile strengths TS1 and TS2 of the hat components 31 and 32 were the same.

[0105] The thicknesses t1 and t2 of the hat members 31 and 32 can be 0.8 mm to 2.3 mm, and can also be 1.4 mm to 2.3 mm. The thicknesses t1 and t2 of the hat members 31 and 32 may be the same or different, but smaller thicknesses are preferable in terms of weight reduction. The lower limits of the thicknesses t1 and t2 of the hat members 31 and 32 can be 0.8 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm, and 2.2 mm. The upper limits of the thicknesses t1 and t2 of the hat members 31 and 32 can be 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, and 2.2 mm.

[0106] In this embodiment, the thickness t1 of the first hat component 31 is set to be smaller than the thickness t2 of the second hat component 32 .

[0107] The thickness t2 of the second hat component 32 is preferably about 1.3 to 1.7 times, for example about 1.5 times, the thickness t1 of the first hat component 31. By setting the thickness ratio t2 / t1 within the above range, the second hat component 32 can start to be crushed after the first hat component 31 has been sufficiently crushed during a side collision.

[0108] The tensile strength ratio TS2 / TS1 of each hat member 31, 32 may be set to 1.3 to 1.7 (e.g., 1.5) while the thickness ratio t2 / t1 is set to 1, or the tensile strength ratio TS2 / TS1 of each hat member 31, 32 may be set to 1 while the thickness ratio t2 / t1 is set to 1.3 to 1.7 (e.g., 1.5).

[0109] The combination of the plate thicknesses t1, t2 and tensile strengths TS1, TS2 of each hat member 31, 32 should be such that, in the event of a side collision, the first hat member 31 begins to crush before the second hat member 32, and the second hat member 32 begins to crush only after the first hat member 31 has been sufficiently crushed.

[0110] It is preferable that the Vickers hardness HV1 and thickness t1 of the first hat member 31, and the Vickers hardness HV2 and thickness t2 of the second hat member 32 satisfy the following relationships: 180≦HV1, HV2≦780, 0.8 mm≦t1, t2≦2.3 mm, and HV1×t1<HV2×t2.

[0111] By satisfying HV1×t1<HV2×t2, the first hat component 31 can be sufficiently strong and the impact energy absorption efficiency can be increased. By satisfying HV2×t1<HV2×t2, cracking of the second hat component 32 during deformation can be suppressed and the impact energy absorption efficiency can be increased. By satisfying 0.8 mm≦t1, the rigidity of the first hat component 31 can be sufficiently secured and the cracking of the first hat component 31 can be suppressed. By satisfying t2×t2<HV1×t1<HV2×t2, the first hat component 31 starts to collapse before the second hat component 32 during a side collision, and the second hat component 32 starts to collapse after the first hat component 31 has been sufficiently crushed.

[0112] In this way, since the impact absorbing member 30 is formed of a plurality of members 31, 32, there is a high degree of freedom in selecting the Vickers hardness HV1, HV2 for each of the plurality of members 31, 32 and the plate thicknesses t1, t2.

[0113] With the above configuration, in this embodiment, the degree of freedom in designing the shape of the impact absorbing member 30 is increased, and a side sill structure 14 and an automobile lower structure 2 that can achieve high side collision resistance performance can be realized.

[0114] In particular, in this embodiment, the impact absorbing members 30 are arranged on both sides (left and right sides) of the width direction X of the vehicle body 1, so that the impact energy absorption effect of the impact absorbing members 30 can be achieved regardless of whether a side collision occurs on the right or left side of the vehicle body 1.

[0115] Furthermore, the impact absorbing member 30 arranged on the side of the battery case 100 can exert an impact energy absorption effect, so that the gap A between the side sill inner 22 and the side wall 100b of the battery case 100 can be prevented from disappearing even in the event of a side collision, thereby preventing the side sill 15 from coming into contact with the side wall 100b of the battery case 100.

[0116] The embodiments of the present disclosure have been described above. However, the present disclosure is not limited to the above-described embodiments. Various modifications of the present disclosure are possible within the scope of the claims. Note that the following mainly describes configurations that differ from the above-described embodiments and modifications, and similar configurations are designated by similar reference numerals and detailed description thereof is omitted.

[0117] 3 is a schematic cross-sectional view showing a main portion of a first modification of the first embodiment of the present disclosure. In the embodiment, the second top plate portion 42 is disposed closer to the side sill outer 21 than the side sill outer 21 and the side sill inner 22. On the other hand, in the first modification of the first embodiment, the second top plate portion 42 is disposed closer to the side sill inner 22 than the side sill outer 21 and the side sill inner 22.

[0118] As a result, in the width direction X, the length from the first top plate portion 41 to the second top plate portion 42 is longer than the length from the second top plate portion 42 to the side sill inner 22 .

[0119] This layout of the second top plate portion 42 allows the space (first hat member 31) between the first top plate portion 41 and the second top plate portion 42 to be increased. As a result, the amount of impact energy that can be absorbed by the first portions 45 a, 46 a of the pair of vertical wall portions 45, 46 through crushing can be increased during a side collision. Furthermore, during a side collision, the first closed cross-sectional portion 61 is crushed first, and then the second closed cross-sectional portion 62 is crushed, thereby absorbing the impact load from the width direction X in order, starting with the members disposed on the outer side in the width direction X. This smooth impact absorption operation increases the efficiency with which the impact energy is absorbed by the impact absorbing member 30.

[0120] [Second Modification of First Embodiment] In the embodiment, the tensile strength TS1 (Vickers hardness HV1) of the first hat component 31 is set lower than the tensile strength TS2 (Vickers hardness HV2) of the second hat component 32. However, this is not necessarily the case. The tensile strength TS1 (Vickers hardness HV1) of the first hat component 31 may be set higher than the tensile strength TS2 (Vickers hardness HV1) of the second hat component 32. In this case, the tensile strength TS1 (Vickers hardness HV1) of the first hat component 31 and the tensile strength TS2 (Vickers hardness HV1) of the second hat component 32 may be swapped. This configuration allows the strength of the side sill outer 21 side of the impact absorbing component 30 to be higher than the strength of the side sill inner 22 side.

[0121] With this configuration, the peak of the impact load acting on the first hat component 31 during a side collision is increased, allowing the first hat component 31 to absorb more impact energy.

[0122] Furthermore, in a second modified example of the first embodiment, a configuration can be exemplified in which the plate thickness t1 of the first hat component 31 and the plate thickness t2 of the second hat component 32 in the first embodiment are interchanged. That is, the plate thickness t1 of the first hat component 31 may be greater than the plate thickness t2 of the second hat component 32. With this configuration, the peak of the impact load acting on the first hat component 31 during a side collision can be increased, allowing the first hat component 31 to absorb more impact energy.

[0123] [Third Modification of First Embodiment] Figure 4 is a schematic perspective view showing a main portion of a third modification of the first embodiment of the present disclosure. The impact absorbing member 30 shown in Figure 4 has a bead 70 formed thereon. The bead 70 may be formed on the first top plate portion 41 of the impact absorbing member 30, or may be formed on the pair of vertical wall portions 45, 46, or may be formed on the second top plate portion 42. In the first modification, the bead 70 is formed on the pair of vertical wall portions 45, 46.

[0124] The bead 70 includes a first bead 71 formed on the first portions 45a, 46a of the pair of vertical wall portions 45, 46, and a second bead 72 formed on the second portions 45b, 46b of the pair of vertical wall portions 45, 46.

[0125] The first bead 71 is provided to increase the resistance of the impact absorbing member 30 to bending deformation and thereby improve the impact absorbing effect in a side collision. The first bead 71 extends in the front-rear direction Y and is formed by undulating the first portions 45a, 46a in the height direction Z. In the third modified example of the first embodiment, the first portions 45a, 46a are formed by recessing the first portions 45a, 46a inward of the closed cross-sectional space 23. Note that the first bead 71 may also be formed by recessing the first portions 45a, 46a outward of the closed cross-sectional space 23. One or more first beads 71 ​​(two in the third modified example) are formed in the width direction X, and each has a uniform shape in the front-rear direction Y.

[0126] The second beads 72 are provided to suppress out-of-plane deformation of the vertical wall portions 45, 46 during a side collision. The second beads 72 extend in the width direction X, and are formed by undulating the second portions 45b, 46b in the height direction Z. In the first modified example, the second portions 45b, 46b are formed by recessing the second portions 45b, 46b inward of the closed cross-sectional space 23. Note that the second beads 72 may also be formed by recessing the second portions 45b, 46b outward of the closed cross-sectional space 23. A plurality of second beads 72 are formed spaced apart in the front-rear direction Y.

[0127] The first bead 71 may be formed on the first top plate portion 41. The second bead 72 may be formed on the first portions 45 a, 46 a of the pair of vertical wall portions 45, 46, or the first bead 71 may be formed on the second portions 45 b, 46 b. The bead 70 may be formed over the entire area of ​​the impact absorbing member 30 in the front-rear direction Y, or may be formed only in the areas where the floor cross members 16, 17 are disposed.

[0128] In this way, by forming the beads 70 on the impact absorbing member 30, buckling of the impact absorbing member 30 during a side collision can be suppressed, and as a result, more impact energy can be absorbed.

[0129] Furthermore, it is difficult to manufacture the impact absorbing member 30 by extruding an aluminum alloy to form multiple second beads 72 spaced apart in the front-rear direction Y, as with the second beads 72. However, if the impact absorbing member 30 is made of a steel plate, such second beads 72 can be formed.

[0130] 5 is a cross-sectional view showing a main portion of a fourth modification of the first embodiment of the present disclosure. In the above-described embodiment, the impact absorbing member 30 is formed of two hat members 31, 32, but this is not necessarily the case. In the fourth modification of the first embodiment, the impact absorbing member 30 is formed of a hat member 35 and a second top plate member 36 as a top plate member installed within the hat member 35.

[0131] The hat member 35 is formed in a hat shape and includes a first top plate portion 41, a pair of vertical wall portions 45, 46, and flanges 47, 48. The hat-shaped portion 40 is formed by the hat member 35. In the fourth modification of the first embodiment, the pair of vertical wall portions 45, 46 are arranged in a tapered shape such that the distance between them narrows as they move outward in the width direction X.

[0132] The second top plate member 36 is disposed between the inner surfaces of the pair of vertical wall portions 45, 46. In the fourth modified example, the second top plate member 36 has a shape that is convex toward the first top plate portion 41 side.

[0133] Such a shape of the second top plate member 36 can increase the efficiency of transmission of impact energy during a side collision, and can also increase the effect of suppressing out-of-plane deformation of the hat member 35 .

[0134] To explain the second top plate member 36 more specifically, the second top plate member 36 includes a second top plate portion 42 parallel to the first top plate portion 41, and flanges 37, 38 provided at both ends of the second top plate portion 42 in the height direction Z and joined to the inner surfaces of a pair of vertical wall portions 45, 46. The upper flange 37 curves so as to move away from the first top plate portion 41 as it approaches the upper vertical wall portion 45. The lower flange 38 curves so as to move away from the first top plate portion 41 as it approaches the lower vertical wall portion 46.

[0135] The tensile strength and thickness of the hat member 35 may be set to be the same as the tensile strength TS1 and thickness t1 of the first hat member 31 of the embodiment. The tensile strength and thickness of the second top plate member 36 may be set to be the same as the tensile strength TS2 and thickness t2 of the second hat member 32 of the embodiment.

[0136] It is preferable that the Vickers hardness HV2 and plate thickness t2 of the hat member 35 and the Vickers hardness HV1 and plate thickness t1 of the second top plate member 36 satisfy the following relationships: 180≦HV1, HV2≦780, 0.8 mm≦t1, t2≦2.3 mm, and HV1×t1<HV2×t2. The meaning of each value is the same as in the first embodiment. By satisfying these conditions, it is possible to more reliably ensure that the first closed cross-sectional portion 61 starts to collapse before the second closed cross-sectional portion 62 during a side collision, and that the second closed cross-sectional portion 62 starts to collapse after the first closed cross-sectional portion 61 has been sufficiently collapsed.

[0137] 6 is a cross-sectional view showing a main portion of a fifth modified example of the first embodiment of the present disclosure. In the embodiment, two closed cross-sectional portions 61, 62 are formed by two hat members 31, 32. However, the impact absorbing member 30 may have three or more closed cross-sectional portions formed by n members (three or more). In this fifth modified example, three closed cross-sectional portions 61, 62, 63 are formed by three hat members 31, 32, 33.

[0138] The impact absorbing member 30 may include the three hat members 31, 32, and 33 described above. The first hat member 31 includes a first top plate portion 41 and first portions 45a and 46a that are part of the pair of vertical wall portions 45 and 46. The second hat member 32 includes a second top plate portion 42 and second portions 45b and 46b that are part of the pair of vertical wall portions 45 and 46. The third hat member 33 includes a third top plate portion 43, third portions 45c and 46c that are part of the pair of vertical wall portions 45 and 46, and a pair of flanges 47 and 48. The third top plate portion 43 connects the pair of third portions 45c and 46c. The first portion 45a, the second portion 45b, and the third portion 45c form a vertical wall portion 45. Similarly, the vertical wall portion 46 is formed by the first portion 46a, the second portion 46b, and the third portion 46c.

[0139] A bead 71 extending uniformly in the front-to-rear direction Y is formed on the first top plate portion 41 of the first hat member 31, but this bead 71 is not necessary. The inner surfaces of flanges 49, 50 which are the base ends of the first portions 45 a, 46 a of the first hat member 31 are joined to the outer surfaces of the second portions 45 b, 46 b of the second hat member 32. The inner surfaces of flanges 79, 80 which are the base ends of the second portions 45 b, 46 b of the second hat member 32 are joined to the outer surfaces of the third portions 45 c, 46 c of the third hat member 33.

[0140] The first hat member 31 and the second top plate 42 form a first closed cross-sectional portion 61. Similarly, the second hat member 32 and the third top plate 43 form a second closed cross-sectional portion 62. Furthermore, the third hat member 33 and the side wall 223 of the side sill inner 22 form a third closed cross-sectional portion 63.

[0141] In the fifth modified example, the lengths of the closed cross-sectional portions 61, 62, and 63 in the width direction X are generally the same, but may be different from one another. For example, in the width direction X, the length of the third closed cross-sectional portion 63 may be greater than the length of the second closed cross-sectional portion 62 and greater than the length of the first closed cross-sectional portion 61, or the length of the third closed cross-sectional portion 63 may be less than the length of the second closed cross-sectional portion 62 and less than the length of the first closed cross-sectional portion 61.

[0142] As described above, even when three or more closed cross-section portions are formed, the order in which each closed cross-section portion 61, 62, 63 begins to collapse and the ease of collapse during a side collision can be set to the desired state by setting the strength and plate thickness of each closed cross-section portion 61, 62, 63.

[0143] [Other Modifications of the First Embodiment] In the first embodiment and each modification described above, a reinforcing member may be interposed between the impact absorbing member 30 and the floor cross members 16, 17. The presence of this reinforcing member can prevent the floor cross members 16, 17 from breaking due to the impact load transmitted from the impact absorbing member 30 to the floor cross members 16, 17 via the side sill 15.

[0144] Furthermore, the impact absorbing member 30 in the first embodiment and each of the modified examples described above may be made of an aluminum alloy, or may be made of a composite material such as CFRP (Carbon Fiber Reinforced Plastics).

[0145] Furthermore, in the above-described first embodiment and each modified example, a configuration has been described in which the impact load during a side collision is transmitted to the floor cross members 16, 17, but not to the battery case 100. However, this does not have to be the case, and the impact load during a side collision may be transmitted to the battery case 100 to absorb the impact.

[0146] Furthermore, in the first embodiment and each modified example described above, the first top plate portion 41 is separated from the side sill outer 21. However, this is not necessarily the case. For example, as shown in FIG. 7 , the first top plate portion 41 may be in contact with the side wall 213 of the side sill outer 21 without being joined thereto. Even with this configuration, during a side collision of the vehicle, the impact absorbing member 30 can undergo two-stage collapse by sequentially crushing the two closed cross-sectional portions 61, 62 while minimizing the influence of deformation of the side sill outer 21. This improves the impact energy absorption efficiency. In other words, during a side collision of the vehicle, the impact absorbing member 30 can deform and absorb impact while being less affected by deformation of the side sill outer 21. This allows the impact absorbing member 30 to more effectively exhibit its impact absorption performance.

[0147] [Second Embodiment] (Vehicle Body) FIG. 8 is an exploded perspective view showing a portion of an automobile body 1 equipped with a lower structure 502 including a side sill structure 514 according to a second embodiment of the present disclosure. FIG. 9 is a cross-sectional view of the lower structure 502 taken along line IX-IX in FIG. 8. Note that FIG. 9 shows a state in which a battery case 600 is fixed to the lower structure 502, and the back side of the cross section is not shown. In this specification, the direction along the traveling direction of the vehicle body 501 (vehicle) is referred to as the longitudinal direction Y of the vehicle body, the traveling direction of the vehicle body is referred to as the front, and the opposite side is referred to as the rear, the up-down direction of the vehicle body is referred to as the height direction Z, and the direction perpendicular to the longitudinal direction Y and the height direction Z is referred to as the width direction X of the vehicle body. In addition, in the width direction X, the direction away from the center of the vehicle body 501 is referred to as the outside, and the opposite direction is referred to as the inside. In this specification, unless otherwise specified, a cross section perpendicular to the longitudinal direction Y is simply referred to as a "cross section."

[0148] As shown in Figures 8 and 9, the vehicle body 501 is a part of a vehicle, and an example of the vehicle is an automobile. An example of an automobile is a passenger car. Examples of the passenger car include a sedan, a coupe, a hatchback, a minivan, and an SUV (Sport Utility Vehicle). The vehicle may be, for example, an electric vehicle (Battery Electric Vehicle) or a hybrid vehicle (HV) including a plug-in hybrid vehicle, and the drive wheels can be driven by electric power from a battery 601 installed under the vehicle body 501.

[0149] The vehicle body 501 includes a frame 510 and a battery case 600 .

[0150] The frame 510 has a front pillar 511 , a roof pillar 512 , a center pillar 513 , a side sill structure 514 including a side sill 515 , floor cross members 516 and 517 , and a floor panel 518 .

[0151] A pair of side sill structures 514 including a front pillar 511, a roof pillar 512, a center pillar 513, and a side sill 515 are provided spaced apart in the width direction X.

[0152] The front pillar 511 has an upper pillar 511a that extends upward and is connected to the roof pillar 512 toward the rear, and a lower pillar 511b that is disposed below the upper pillar 511a.

[0153] The roof pillar 512 is disposed on the roof portion of the vehicle body 501 and extends rearward from the pillar upper 511a.

[0154] The center pillar 513 is disposed along the height direction Z and connects the roof pillar 512 and the side sill 515 .

[0155] The side sill 515 is an example of a "structural member" in the present disclosure. The side sill 515 is provided at the lower part of the outer portion of the vehicle body 501 in the width direction X. The side sill 515 is connected to the lower part of the center pillar 513 and is disposed along the front-rear direction Y of the vehicle body 501. The side sill 515 forms a closed cross-sectional shape in a cross section perpendicular to the front-rear direction Y.

[0156] The floor cross members 516, 517 are members extending in the width direction X, and are disposed between a pair of left and right side sills 515, 515 to connect these side sills 515, 515. The floor cross members 516, 517 are disposed on the front seat side of the vehicle interior (cabin) formed by the vehicle body 501. The floor cross members 516, 517 are disposed spaced apart in the fore-and-aft direction Y, with the floor cross member 17 disposed behind the floor cross member 16. The floor cross members 516, 517 each have a hat-shaped cross section perpendicular to the width direction X, and form a closed cross-sectional shape in cooperation with a floor panel 518. The floor panel 518 forms the bottom of the cabin of the vehicle body 501 and is fixed to the floor cross members 516, 517.

[0157] Slide rails (not shown) are installed on the floor cross members 516 and 517. The slide rails support seats (not shown) on which passengers sit.

[0158] A plate-shaped floor panel 518 is installed below the floor cross members 516, 517. A battery case 600 is installed below the floor panel 518. The battery case 600 houses a battery 601, which may be a lithium-ion battery or the like.

[0159] The side sill 515 is located outward of the battery 601 in the width direction X to protect the battery 601 from a side collision of the vehicle with a utility pole or the like (pole side collision). Note that, hereinafter, a side collision of the vehicle will also be simply referred to as a "side collision." The side sill 515 extends along the front-rear direction Y. The battery case 600 may be fixed to the side sill 515. In the second embodiment, a widthwise end 600a of the battery case 600 is fixed to, for example, a lower wall 724 of a side sill inner 522 (described later) of the side sill 515. A side wall 600b rising upward from the widthwise end 600a of the battery case 600 is formed in an intermediate portion of the battery case 600 in the width direction X as a protective wall for the battery 601. The battery 601 is disposed inside the side wall 600b in the width direction X. A gap 500A is formed between the side wall 600b and the side sill inner 522. The gap 500A varies depending on the vehicle model, but can be a value of approximately several millimeters to several hundred millimeters. Note that the configuration of the battery case 600 described in this embodiment is an example, and the specific shape and arrangement are not limited as long as the battery case 600 is disposed inside the side sill 515 in the width direction X.

[0160] (Side Sill Structure) In the following, when describing the side sill structures 514, unless otherwise specified, the configuration will be described in a cross section perpendicular to the front-rear direction Y. A pair of side sill structures 514 are provided spaced apart in the width direction X. The lower structure 502 of the vehicle body 501 includes each side sill structure 514 and a battery case 600.

[0161] Each side sill structure 514 includes the above-mentioned side sill 515 and an impact absorbing member 530 .

[0162] The side sill 515 includes a side sill outer 521 and a side sill inner 522 disposed on the inner side of the side sill outer 521 in the width direction X.

[0163] The side sill outer 521 and the side sill inner 522 each have a hat-shaped cross section, and cooperate to form a closed cross-sectional space 523 in the side sill 515 .

[0164] The side sill outer 521 has a shape that opens inward in the width direction X, and the side sill inner 522 has a shape that opens outward in the width direction X. The side sill outer 521 and the side sill inner 522 are fixed to each other by joining means such as welding or fastening members with their respective flanges 711, 721; 715, 725 abutting against each other. In this embodiment, the side sill outer 521 and the side sill inner 522 are joined to each other by, for example, welding. Various welding methods can be used, such as spot welding, TIG welding, arc welding, laser welding, and plasma welding. Various fastening members can be used, such as structural adhesives, rivets, belts, and nuts. The joining methods for joining other parts of the vehicle body 501 are similar to those described above.

[0165] The side sill outer 521 has an upper flange 711, an upper wall 712 extending outward from the upper flange 711 in the width direction X, a side wall 713 extending downward from the upper wall 712, a lower wall 714 extending inward from the side wall 713 in the width direction X, and a lower flange 715 extending downward from the lower wall 714.

[0166] The side sill inner 522 has an upper flange 721, an upper wall 722 extending inward in the width direction X from the upper flange 721, a side wall 723 extending downward from the upper wall 722 and joined to the floor cross members 516, 517, a lower wall 724 extending outward from the side wall 723 in the width direction X, and a lower flange 725 extending downward from the lower wall 724.

[0167] The upper flanges 711 and 721 are joined to each other by the joining method described above, and similarly, the lower flanges 715 and 725 are joined to each other by the joining method described above.

[0168] The upper wall 712 and the lower wall 714 of the side sill outer 521 may be parallel to each other along the width direction X, or may be inclined so that the distance between them in the height direction Z changes as they move outward in the width direction X. Similarly, the upper wall 722 and the lower wall 724 of the side sill inner 522 may be parallel to each other along the width direction X, or may be inclined so that the distance between them in the height direction Z changes as they move inward in the width direction X.

[0169] The side sill 515 may have a shape that is symmetrical in the width direction X or a shape that is asymmetrical in the width direction X, and the specific shape is not limited.

[0170] (Major Configuration of Impact Absorbing Member) The impact absorbing member 530 plastically deforms in cooperation with the side sill 515 during a side collision, thereby absorbing the impact energy of the side collision.

[0171] The impact absorbing member 530 is formed of multiple members (in this embodiment, a first hat member 31 and a second hat member 32) and is supported by the side sill 515 within a closed cross-sectional space 523 of the side sill 515. That is, the impact absorbing member 530 has a second hat member 532 and a first hat member 531, each of which is hat-shaped in a cross section perpendicular to the front-rear direction Y and is aligned in the width direction X. The impact absorbing member 530 is formed by combining the second hat member 532 and the first hat member 531.

[0172] The impact absorbing member 530 comprises a first top plate portion 531e extending in the height direction Z, a hat-shaped portion 540 having a pair of vertical wall portions 545, 546 extending along the width direction X from both ends of the first top plate portion 531e in the height direction Z, and a second top plate portion 532e arranged at a distance from the first top plate portion 531e in the width direction X and connecting the pair of vertical wall portions 545, 546.

[0173] The second top plate portion 532e divides the inner space of the hat-shaped portion 540 in the width direction X, thereby forming a first closed cross-sectional portion 561 including the first top plate portion 531e and a second closed cross-sectional portion 562 adjacent to the first closed cross-sectional portion 561 in the width direction X. The impact absorbing member 530 is spaced apart from the side sill outer 521, or is in contact with the side sill outer 521 without being joined thereto.

[0174] The first hat member 531 comprises a pair of first flanges 531a, 531b joined to the second top plate portion 532e, a pair of first vertical wall portions 531c, 531d extending from the pair of first flanges 531a, 531b, and a first top plate portion 531e connecting the pair of first vertical wall portions 531c, 531d.

[0175] The second hat member 532 comprises a pair of second flanges 532a, 532b supported by the side sill 515, a pair of second vertical wall portions 532c, 532d extending from the pair of second flanges 532a, 532b, and a second top plate portion 532e connecting the pair of second vertical wall portions 532c, 532d.

[0176] (Effects of Main Configuration of Impact Absorbing Member) Because the impact absorbing member 530 has the above-described configuration, numerous ridge lines 532f, 532g, 532h, 532i, 531f, 531g, 531h, and 531i are formed in the impact absorbing member 530. As a result, during a side collision, the action of the numerous ridge lines 532f, 532g, 532h, 532i, 531f, 531g, 531h, and 531i in the impact absorbing member 530 can increase the efficiency of impact energy absorption when the closed cross-sectional shapes of the second hat member 532 and the first hat member 531 deform. In particular, because numerous ridge lines 531f, 531g, 531h, and 531i are formed in the first hat member 531, which is the first to receive an impact load in the impact absorbing member 530, the amount of impact energy absorbed when the first hat member 531 is crushed can be increased. As a result, the impact energy absorption efficiency of the impact absorbing member 530 can be improved. This allows the impact absorbing member 530 to absorb a larger amount of impact energy while reducing its weight, thereby improving the weight efficiency of impact energy absorption. Furthermore, by adjusting the shapes of the second hat member 532 and the first hat member 531, the timing at which the second hat member 532 and the first hat member 531 start to deform during a side collision and the manner in which they deform can be set. This allows the impact absorbing behavior of the impact absorbing member 530 during a side collision to be set according to the vehicle characteristics (such as the presence or absence of a battery case 600 and the layout of the battery case 600). Therefore, the vehicle can achieve higher side collision resistance. Furthermore, because the impact absorbing member 530 is formed from multiple members (in this embodiment, the second hat member 532 and the first hat member 531), the degree of freedom in designing the shape is greater than when the impact absorbing member 530 is formed from a single member.

[0177] (Detailed Configuration Example of Impact Absorbing Member) The impact absorbing member 530 has multiple closed cross-sectional portions (in this embodiment, two closed cross-sectional portions 561, 562 formed by the side sill 515, the second hat member 532, and the first hat member 531) in the width direction X, so that the multiple closed cross-sectional portions 561, 562 are crushed in stages during a side collision, thereby absorbing more impact energy. Furthermore, the impact absorbing member 530 is formed of multiple members (in this embodiment, two hat members 531, 532). As a result, by combining the strength (tensile strength) and plate thickness of each hat member 531, 532, the crushing characteristics of each closed cross-sectional portion 561, 562 can be adjusted to a desired state. For example, the first hat member 531 may be crushed relatively more during a side collision (at the beginning of the side collision) to absorb impact, and the second hat member 532 may be crushed relatively less during a side collision to suppress the amount of intrusion of the side sill 515 or the like inward in the width direction during a side collision.

[0178] In this embodiment, the impact absorbing member 530 is formed to have a uniform cross-sectional shape throughout the entire impact absorbing member 530, but the shape may vary at each portion in the front-rear direction Y. In this embodiment, the impact absorbing member 530 is formed to have a shape that convex outward in the width direction X, but may also be formed to have a shape that convex inward in the width direction X (a shape symmetrical in the width direction X to the shape shown in FIG. 9 ). The impact absorbing member 530 may be installed over the entire area where the side sill 515 is arranged in the front-rear direction Y, or may be installed over only a portion of the area. In this embodiment, the impact absorbing member 530 is arranged continuously from the front end 515 a to the rear end 515 b of the side sill 515.

[0179] In this embodiment, the shock absorbing member 530 is formed to have a vertically symmetrical shape, but may have a vertically asymmetrical shape. By forming the shock absorbing member 530 from multiple components, it is possible to easily manufacture the shock absorbing member 530 in either a vertically symmetrical shape or a vertically asymmetrical shape.

[0180] In the second embodiment, the impact absorbing member 530 is disposed between the side wall 713 of the side sill outer 521 and the side wall 723 of the side sill inner 522. In the second embodiment, the impact absorbing member 530 has a tapered shape in which the length in the height direction Z decreases toward the outside in the width direction X. The impact absorbing member 530 is elongated in the width direction X, and the length in the width direction X is greater than the length in the height direction Z.

[0181] (Detailed Configuration Example of Second Hat Member) The second hat member 532 is disposed adjacent to the side sill inner 522 .

[0182] The second hat member 532 has a pair of second flanges 532a, 532b, a pair of base end side second ridge portions 532f, 532g, a pair of second vertical wall portions 532c, 532d, a pair of tip end side second ridge portions 532h, 532i, and a second top plate portion 532e.

[0183] The pair of second flanges 532a, 532b of the second hat member 532 are portions joined to the side sill 515, and in this embodiment, are joined by the above-mentioned joining method to the inner surface of the side wall 723 of the side sill inner member 522. The second flanges 532a, 532b do not have to be joined directly to the side sill inner member 522, but may be joined to the side sill inner member 522 via another member such as a patch (reinforcement member).

[0184] In this manner, the second flanges 532a, 532b of the impact absorbing member 530 are joined to the side sill inner panel 522. With this configuration, during a side collision, the impact load acting on the first top plate portion 531e can be transmitted with high transmission efficiency from the side sill inner panel 522 to the floor cross members 516, 517. Therefore, the side sill 515, the impact absorbing member 530, and the floor cross members 516, 517 work together to absorb more impact energy. As a result, collision of the side sill 515 with the battery case 600 during a side collision can be reduced.

[0185] Although the length of the second flanges 532a, 532b is not particularly limited, if the length is shorter than the length of the second top plate portion 532e, the overall length of the second hat member 532 in the height direction Z can be shortened. On the other hand, if the length of the second flanges 532a, 532b is longer than the length of the second top plate portion 532e, the bonding strength between the second hat member 532 and the side sill 515 in the height direction Z can be increased.

[0186] The upper second flange 532a extends upward from the upper second vertical wall portion 532c, and the lower second flange 532b extends downward from the lower second vertical wall portion 532d. These second flanges 532a, 532b are spaced apart from each other, and the second hat member 532 has a shape in which the inner side in the width direction X is open toward the side sill inner member 522. As such, it is preferable that the impact absorbing member 530 is joined to the side sill inner member 522 only by the second flanges 532a, 532b, and that no other portion of the impact absorbing member 530 is disposed between the second flanges 532a, 532b in the height direction Z. This configuration allows the impact absorbing member 530 to be made lighter. Furthermore, when spot welding the side sill inner panel 522 and the impact absorbing member 530, the second flanges 532a, 532b, which are disposed outward in the height direction Z from the pair of second vertical wall portions 532c, 532d, and the side sill inner panel 522 can be clamped and welded using a welding machine. As described above, in this embodiment, the outward second flanges 532a, 532b are disposed outward in the height direction Z from the pair of second vertical wall portions 532c, 532d. The lower end of the upper second flange 532a and the upper end of the lower second flange 532b are connected to the second vertical wall portions 532c, 532d via the base-side second ridge portions 532f, 532g.

[0187] The base-side second ridge portions 532f, 532g are portions that are curved in an arc shape in cross section and have the function of increasing the amount of impact energy absorbed by the second hat component 532 during impact absorption. The radius of curvature of the base-side second ridge portions 532f, 532g in cross section is approximately several mm to several tens of mm.

[0188] The pair of second vertical wall portions 532c, 532d of the second hat member 532 are arranged along the width direction X, and the distance between the pair of second vertical wall portions 532c, 532d increases toward the side sill inner 522. This layout of the pair of second vertical wall portions 532c, 532d allows the second hat member 532 to receive in a balanced manner the impact load acting inward in the width direction X from the side sill outer 521. This increases the amount of impact energy absorbed by the impact absorbing member 530 during a side collision. The pair of second vertical wall portions 532c, 532d may be arranged parallel to (horizontally with) the width direction X, or the distance between the pair of second vertical wall portions 532c, 532d may decrease toward the side sill inner 522.

[0189] The tip end of the upper second vertical wall portion 532c and the tip end of the lower second vertical wall portion 532d are connected to the second top plate portion 532e via tip side second ridge portions 532h and 532i.

[0190] The tip-side second ridge portions 532h, 532i are portions that are curved in an arc shape in cross section and have the function of increasing the amount of impact energy absorbed by the second hat component 532 during impact absorption. The radius of curvature of the tip-side second ridge portions 532h, 532i in cross section is approximately several mm to several tens of mm.

[0191] The second top plate portion 532e suppresses out-of-plane deformation such as causing the pair of second vertical wall portions 532c, 532d connected to the second top plate portion 532e to collapse toward the inside of these second vertical wall portions 532c, 532d. In this embodiment, the second top plate portion 532e is disposed parallel to the first top plate portion 531e of the first hat member 531. The second top plate portion 532e connects the pair of second vertical wall portions 532c, 532d. In addition, the second top plate portion 532e is joined to the pair of first flanges 531a, 531b by the joining method described above.

[0192] In this embodiment, the second top plate portion 532e is parallel to the height direction Z. With this configuration, in the event of a side collision, the horizontal load acting on the second top plate portion 532e via the side wall 713 of the side sill outer 521 and the first hat component 531 can be borne by the second top plate portion 532e in a balanced manner in the height direction Z. This allows the second hat component 532 to be crushed to a greater extent, thereby absorbing more impact energy.

[0193] The second top plate portion 532e is disposed in a middle portion of the impact absorbing member 530 in the rising direction (width direction X) of the pair of second vertical wall portions 532c, 532d. The presence of the second top plate portion 532e makes it possible to shorten the outer and inner portions of the impact absorbing member 530 of the second top plate portion 532e in the width direction X. As a result, out-of-plane deformation of the pair of second vertical wall portions 532c, 532d and a pair of first vertical wall portions 531c, 531d (described later) of the first hat member 531 during a side collision can be suppressed, and the amount of energy absorbed by wall buckling motion can be increased.

[0194] The second top plate portion 532e is positioned closer to the side sill inner portion 522 than the side sill outer portion 521 or the side sill inner portion 522. This allows the length (height H531) of the first hat component 531 to be increased. As a result, the length (impact absorption stroke) over which the first hat component 531 can be crushed in the width direction X to absorb impact during a side collision can be increased. Furthermore, the space within the second hat component 532 can be reduced. As a result, out-of-plane deformation of the pair of second vertical wall portions 532c, 532d of the second hat component 532 can be suppressed during a side collision. Furthermore, during a side collision, the first hat component 531 is crushed first, followed by the second hat component 532, thereby absorbing the impact load from the width direction X in order, starting with the components located on the outer side in the width direction X. This smooth impact absorption operation increases the impact energy absorption efficiency of the impact absorbing component 530.

[0195] (Detailed Configuration Example of First Hat Component) The first hat component 531 is disposed closer to the side sill outer component 521 than the side sill inner component 522. Due to this arrangement of the second hat component 532 and the first hat component 531, in the event of a side collision, the first hat component 531 can be crushed first to absorb the impact energy.

[0196] The first hat member 531 has a pair of first flanges 531a, 531b, a pair of base end side first ridge portions 531f, 531g, a pair of first vertical wall portions 531c, 531d, a pair of tip end side first ridge portions 531h, 531i, and a first top plate portion 531e.

[0197] The pair of first flanges 531a, 531b of the first hat component 531 are joined by the joining method described above to the outer surface of the second top plate portion 532e of the second hat component 532. The first flanges 531a, 531b do not have to be joined directly to the second top plate portion 532e, and may be joined to the second top plate portion 532e via a patch (reinforcement member).

[0198] The lengths of the first flanges 531a, 531b are not particularly limited, but it is preferable that they do not extend beyond the second top plate portion 532e in the height direction Z in order to reduce the weight of the first hat component 531. Furthermore, end surfaces 531j, 531k of the first flanges 531a, 531b face the height direction Z and do not face the second hat component 532 in the height direction Z. The first flanges 531a, 531b may contact the second top plate portion 532e of the second hat component 532 but may not contact the tip-side second ridge portions 532h, 532i. With the first flanges 531a, 531b arranged as described above, the vertical wall portions 531c, 531d of the first hat member 531 are arranged so that the vertical wall portions 532c, 532d of the second hat member 532 are out of the regions extending in the longitudinal direction of the vertical wall portions 532c, 532d. With this layout of the first hat member 531, when an impact load acts on the first hat member 531, the first flanges 531a, 531b can firmly support the vertical wall portions 531c, 531d. As a result, more impact energy can be absorbed by promoting deformation of the vertical wall portions 531c, 531d between the base-side first ridge portions 531f, 531g and the tip-side first ridge portions 531h, 531i.

[0199] The upper first flange 531a extends upward from the upper first vertical wall portion 531c, and the lower first flange 531b extends downward from the lower first vertical wall portion 531d. These first flanges 531a, 531b are spaced apart from each other, and the second hat component 532 has a shape in which the inner side in the width direction X is open toward the side sill inner panel 522. As such, it is preferable that the first hat component 531 is joined only at the second top plate portion 532e of the second hat component 532, and that no other portion of the impact absorbing component 530 is disposed between the first flanges 531a, 531b in the height direction Z. This configuration allows the impact absorbing component 530 to be made lighter. Furthermore, when spot welding the second hat component 532 and the first hat component 531, the first flanges 531a, 531b, which are disposed outward in the height direction Z from the pair of first vertical wall portions 531c, 531d, and the second top plate portion 532e can be sandwiched and welded using a welding machine. As described above, in this embodiment, the outward first flanges 531a, 531b are disposed outward in the height direction Z from the pair of first vertical wall portions 531c, 531d. The lower end of the upper first flange 531a and the upper end of the lower first flange 531b are connected to the first vertical wall portions 531c, 531d via the base-end first ridge portions 531f, 531g.

[0200] The base-side first ridge portions 531f, 531g are portions that are curved in an arc shape in cross section and have the function of increasing the amount of impact energy absorbed by the first hat component 531 during impact absorption. The radius of curvature of the base-side first ridge portions 531f, 531g in cross section is approximately several millimeters to several tens of millimeters. The radius of curvature of the base-side first ridge portions 531f, 531g may be the same as the radius of curvature of the base-side second ridge portions 532f, 532g of the second hat component 532, may be less than the radius of curvature of the base-side second ridge portions 532f, 532g, or may be greater than the radius of curvature of the base-side second ridge portions 532f, 532g.

[0201] The pair of first vertical wall portions 531c, 531d of the first hat component 531 are arranged along the width direction X, and the distance between the pair of first vertical wall portions 531c, 531d increases toward the side sill inner 522. This layout of the pair of first vertical wall portions 531c, 531d allows the impact load acting on the inside in the width direction X from the side sill outer 521 to be transmitted in a balanced manner from the first hat component 531 to the second hat component 532. This increases the amount of impact energy absorbed by the impact absorbing component 530 during a side collision. The pair of first vertical wall portions 531c, 531d may be arranged parallel to (horizontally with) the width direction X, or the distance between the pair of first vertical wall portions 531c, 531d may decrease toward the side sill inner 522.

[0202] The tip end of the upper first vertical wall portion 531c and the tip end of the lower first vertical wall portion 531d are connected to the first top plate portion 531e via tip side first ridge portions 531h and 531i.

[0203] The tip-side first ridge portions 531h, 531i are portions that are curved in an arc shape in cross section and have the function of increasing the amount of impact energy absorbed by the first hat component 531 during impact absorption. The radius of curvature of the tip-side first ridge portions 531h, 531i in cross section is approximately several mm to several tens of mm.

[0204] The first top plate portion 531e and the first vertical wall portions 531c and 531d of the first hat member 531 are the portions of the impact absorbing member 530 that are first subjected to an impact load during a side collision.

[0205] In this embodiment, the first top plate portion 531e is disposed closer to the side sill outer portion 521 than the side sill inner portion 522. This ensures a sufficient length for the impact absorbing member 530 in the width direction X. As a result, in the event of a side collision, the length over which the impact absorbing member 530 can be crushed in the width direction X and absorb impact (impact absorption stroke) can be increased.

[0206] In this embodiment, the first top plate portion 531 e is in contact with the side wall 713 of the side sill outer 521 , but is not joined to the side wall 713 of the side sill outer 21 .

[0207] With this preferred configuration, the work of installing the impact absorbing member 530 inside the side sill 515 is easy. This is because the work of joining the first top plate portion 531e to the side wall 713 of the side sill outer 521 is not necessary. If the first top plate portion 531e were to be joined to the side wall 713 of the side sill outer 521 by welding, a welding machine would need to be sandwiched between the first top plate portion 531e and the side wall 713. This makes the work of installing the impact absorbing member 530 inside the side sill 515 time-consuming. This kind of time-consuming work is present whether the type of welding is spot welding, laser welding, or bonding with an adhesive.

[0208] Furthermore, with this preferred configuration, in the event of a side collision of the vehicle, the impact absorbing member 530 can undergo two-stage collapse by sequentially crushing the two closed cross-sectional portions 561, 562 while minimizing deformation of the side sill outer 521, thereby increasing the efficiency of absorbing impact energy. In other words, in the event of a side collision of the vehicle, the impact absorbing member 530 can deform and absorb impact while being less affected by deformation of the side sill outer 521. This allows the impact absorbing performance of the impact absorbing member 530 to be exhibited more effectively.

[0209] The first top plate portion 531e may be spaced apart from the side wall 713 of the side sill outer 521 to such an extent that it does not come into contact with the side wall 713 even when the vehicle vibrates during vehicle travel. If the first top plate portion 531e is spaced apart from the side sill outer 521 in this manner, deformation of the side sill outer 521 due to impact transmission from the side sill outer 521 to the impact absorbing member 530 and the side sill inner 522 can be suppressed in the event of a relatively minor side collision of the vehicle. When a relatively minor side collision of the vehicle occurs, impact acts on the side sill outer 521, but this impact is not transmitted from the side sill outer 521 to the impact absorbing member 530. Therefore, impact transmission to the side sill inner 522 via the impact absorbing member 530 is not required. In this case, the amount of deformation of the side sill 515 is small, thereby suppressing degradation of the vehicle's driving performance (such as straight-line running performance). Furthermore, when repairing the vehicle, while it is necessary to repair the side wall 713 of the side sill outer 521, there is no need to repair the impact absorbing member 530 or the side sill inner 522, thereby reducing the effort and cost required for maintaining the vehicle. On the other hand, when a large side collision occurs to the vehicle, the impact is transmitted from the side sill outer 521 to the side sill inner 522 via the impact absorbing member 530, and the impact energy can be efficiently absorbed by the deformation of the impact absorbing member 530 and the side sill inner 522.

[0210] It is preferable that the first top plate portion 531e be arranged parallel to the side wall 713, since the entire first top plate portion 531e will bear the impact load from the side wall 713 of the side sill outer 521. The first top plate portion 531e connects the pair of first vertical wall portions 531c, 531d. The first top plate portion 531e is the portion of the impact absorbing member 530 that has the shortest length in the height direction Z. It is preferable that the first top plate portion 531e be arranged parallel to the second top plate portion 532e, since this can increase the efficiency of absorbing impact energy acting in the width direction X during a side collision.

[0211] With the above configuration, a pair of vertical wall portions 531c, 531d (a pair of first portions) of the first hat member 531 and a pair of vertical wall portions 532c, 532d (a pair of second portions) of the second hat member 532 cooperate to form a pair of vertical wall portions 545, 546 in the hat-shaped portion 540 of the impact absorbing member 530.

[0212] (Configuration Example of First Closed Cross-Section Portion and Second Closed Cross-Section Portion) With the above configuration, the second closed cross-section portion 562 is formed by the second top plate portion 532e, the pair of tip-side second ridge portions 532h, 532i, the pair of second vertical wall portions 532c, 532d, the pair of base-side second ridge portions 532f, 532g, the pair of second flanges 532a, 532b, and the side wall 723 of the side sill inner 522. Furthermore, the first closed cross-section portion 561 is formed by the first top plate portion 531e, the pair of tip-side first ridge portions 531h, 531i, the pair of first vertical wall portions 531c, 531d, the pair of base-side first ridge portions 531f, 531g, the pair of first flanges 531a, 531b, and the second top plate portion 532e.

[0213] In the second embodiment, the second vertical wall portions 532c, 532d of the second hat component 532 are not aligned in a straight line with the corresponding first vertical wall portions 531c, 531d of the first hat component 531. Due to this stepped, linear layout, in the event of a side collision, the impact load acting from the first top plate portion 531e on the impact absorbing member 530 can be absorbed by many of the ridge portions 531f to 531i, 532f to 532i.

[0214] (Examples of Materials for Impact Absorbing Member) Next, the materials and the like for the impact absorbing member 530 will be described.

[0215] When the impact absorbing member 530 is made of a steel plate, it is possible to use iron, which is relatively inexpensive in price compared to aluminum, which is relatively expensive in price, and the manufacturing cost of the car body 501 can be reduced.

[0216] In the second embodiment, the second hat member 532 and the first hat member 531 of the impact absorbing member 530 are each formed of a steel plate. The tensile strength of each of the hat members 531, 532 can be, for example, 590 MPa to 2.5 GPa. More specifically, the lower limit of the tensile strength of each of the hat members 531, 532 may be 780 MPa, 980 MPa, 1.3 GPa, 1.5 GPa, 1.7 GPa, 2.0 GPa, or 2.3 GPa. The upper limit of the tensile strength of each of the hat members 31, 32 may be 1.5 GPa, 1.7 GPa, 2.0 GPa, or 2.3 GPa.

[0217] The tensile strength can be evaluated in accordance with JIS Z 2241:2011. An example of a test piece for measuring the tensile strength is the No. 5 test piece of JIS Z 2241:2011. Examples of positions from which the tensile test piece is taken include the central portions of the pair of second vertical wall portions 532c, 532d of the second hat member 532 and the central portions of the pair of first vertical wall portions 531c, 531d of the first hat member 531.

[0218] The Vickers hardness HV1, HV2 of each hat member 531, 532 can be exemplified as the Vickers hardness HV1, HV2 corresponding to the tensile strength of each hat member 531, 532. Examples of the Vickers hardness HV1, HV2 of each hat member 531, 532 are 240 to 780. The lower limit of the Vickers hardness HV1, HV2 of each hat member 531, 532 may be 180 corresponding to 590 MPa, 240 corresponding to 780 MPa, 300 HV corresponding to 980 MPa, 400 corresponding to 1.3 GPa, 460 corresponding to 1.5 GPa, 520 corresponding to 1.7 GPa, 620 corresponding to 2.0 GPa, or 710 corresponding to 2.3 GPa. In addition, the upper limit of the Vickers hardness HV1, HV2 of each hat member 531, 532 may be 460 corresponding to 1.5 GPa, 520 corresponding to 1.7 GPa, 620 corresponding to 2.0 GPa, 710 corresponding to 2.3 GPa, or 780 corresponding to 2.5 GPa.

[0219] The Vickers hardness of each hat component 531, 532 can be measured as follows. Vickers hardness (HV1) "HV1" refers to the "hardness symbol" when a Vickers hardness test is conducted with a test force of 1 kgf (9.807 N) (JIS Z 2244-1:2020). Vickers hardness is measured as follows. First, a measurement sample is cut out from a flat portion of the first hat component 531, such as the first top plate portion 531e, so that the cut surface (measurement surface) is parallel to the thickness direction of the flat portion. The cut surface is then embedded in resin and polished. Ten measurements are then taken at 1 / 4 of the plate thickness depth from the surface of the measurement sample on the cut surface (measurement surface) at 0.5 mm intervals with a test force of 1 kgf (9.807 N), and the average is calculated.

[0220] Vickers hardness (HV2) "HV2" is a value obtained by cutting a measurement sample from a flat portion such as the second top plate portion 532e of the second hat member 532 instead of the first top plate portion 531e and performing the above-mentioned test.

[0221] In the second embodiment, the tensile strength TS1 (Vickers hardness HV1) of the first hat member 531 is set lower than the tensile strength TS2 (Vickers hardness HV2) of the second hat member 532 (TS1<TS2). That is, the strength of the side sill outer 521 side of the impact absorbing member 530 is set lower than the strength of the side sill inner 522 side.

[0222] With such tensile strength settings, during a side collision, the first hat component 531 begins to deform before the second hat component 532, enabling it to absorb impact energy. In the closed cross-sectional space 523, the first hat component 531, which is located farther from the battery case 600, deforms first, postponing the deformation timing of the second hat component 532, which is closer to the battery case 600. In other words, deformation of the second hat component 532 can be suppressed until the first hat component 531 is sufficiently deformed. This increases the amount of impact energy absorbed by the crushing of the first hat component 531 and prevents the side sill inner panel 522, which crushes together with the crushing of the second hat component 532, from contacting the side wall 600b of the battery case 600. Furthermore, the high strength of the second hat component 532 allows the second hat component 532 to absorb a greater amount of impact energy.

[0223] The tensile strength TS2 (Vickers hardness HV2) of the second hat component 532 is preferably approximately 1.3 to 1.7 times the tensile strength TS1 (Vickers hardness HV1) of the first hat component 531, with approximately 1.5 times being an example. By setting the tensile strength TS2 in this manner, the first hat component 531 is crushed during a side collision, and the second hat component 532 begins to crush after the first hat component 531 has been sufficiently crushed. This also prevents cracks from occurring in the first hat component 531, which is severely crushed during a side collision, reducing the impact energy absorption efficiency. A more specific example of the tensile strengths is a configuration in which the tensile strength TS1 of the first hat component 531 is 980 MPa and the tensile strength TS2 of the second hat component 532 is 1.5 GPa. This configuration allows for a higher impact energy absorption value than if the tensile strengths TS1 and TS2 of the hat components 531 and 532 were the same.

[0224] (Example of Plate Thickness of Impact-Absorbing Member) The plate thickness of each hat member 531, 532 can be 0.8 mm to 2.3 mm, for example. The plate thickness of each hat member 531, 532 may be the same or different, but a smaller thickness is preferable in terms of weight reduction. In the second embodiment, the plate thickness t1 of the first hat member 531 is set smaller than the plate thickness t2 of the second hat member 532. The plate thickness t2 of the second hat member 532 is preferably approximately 1.3 to 1.7 times the plate thickness t1 of the first hat member 531, and approximately 1.5 times is an example. By setting the plate thickness ratio t2 / t1 within the above range, it is possible to start crushing the second hat member 532 after the first hat member 531 has been sufficiently crushed during a side collision. Examples of lower limits of the thicknesses t1 and t2 of the hat members 531 and 532 are 0.8 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2.0 mm, and 2.2 mm, while examples of upper limits of the thicknesses t1 and t2 of the hat members 531 and 532 are 1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, and 2.2 mm.

[0225] (Example of strength ratio and thickness ratio of hat members) The tensile strength ratio TS2 / TS1 of each hat member 531, 532 may be set to 1.3 to 1.7 (e.g., 1.5) while the thickness ratio t2 / t1 is set to 1, or the tensile strength ratio TS2 / TS1 of each hat member 531, 532 may be set to 1 while the thickness ratio t2 / t1 is set to 1.3 to 1.7 (e.g., 1.5).

[0226] It is preferable that the combination of the plate thicknesses t1, t2 and tensile strengths TS1, TS2 of each hat member 531, 532 is such that, in the event of a side collision, the first hat member 531 begins to crush before the second hat member 532, and the second hat member 532 is crushed only after the first hat member 531 has been sufficiently crushed.

[0227] It is preferable that the Vickers hardness HV1 and thickness t1 of the first hat member 531 and the Vickers hardness HV2 and thickness t2 of the second hat member 532 satisfy the following relationships: 180≦HV1, HV2≦780, 0.8 mm≦t1 t2≦2.3 mm, and HV1×t1<HV2×t2.

[0228] By satisfying HV1×t1<HV2×t2, the first hat component 531 can be sufficiently strong and the impact energy absorption efficiency can be increased. By satisfying HV2×t1<HV2×t2, cracking of the second hat component 532 during deformation can be suppressed and the impact energy absorption efficiency can be increased. By satisfying 0.8 mm≦t1, the rigidity of the first hat component 531 can be sufficiently secured and the cracking of the first hat component 531 can be suppressed. By satisfying t2×t2<HV1×t1<HV2×t2, the first hat component 531 starts to collapse before the second hat component 532 during a side collision, and the second hat component 532 starts to collapse after the first hat component 531 has been sufficiently crushed.

[0229] In this way, since the impact absorbing member 530 is formed by the plurality of hat members 531, 532, there is a high degree of freedom in selecting the Vickers hardness HV1, HV2 for each of the plurality of hat members 531, 532 and the plate thicknesses t1, t2.

[0230] (Example of effect of the second embodiment) With the above configuration, the second embodiment allows for greater freedom in setting the shape of the impact absorbing member 530, and can realize a side sill structure 514 and an automobile lower structure 502 that can achieve high side collision resistance performance.

[0231] In particular, in this embodiment, the impact absorbing members 530 are arranged on both sides (left and right sides) of the width direction X of the vehicle body 501, so that the impact energy absorption effect of the impact absorbing members 530 can be achieved regardless of whether a side collision occurs on the right or left side of the vehicle body 501.

[0232] Furthermore, the impact absorbing member 530 arranged on the side of the battery case 600 can provide an impact energy absorbing effect, thereby providing an effect of protecting the battery case 600 and the battery 601 inside the battery case 600.

[0233] [First Modification of Second Embodiment] Fig. 10 is a schematic cross-sectional view showing a main portion of a first modification of the second embodiment of the present disclosure. In the embodiment, the second top plate portion 532e is disposed closer to the side sill inner 522 of the side sill outer 521 and the side sill inner 522. On the other hand, as shown in Fig. 10, in the first modification of the second embodiment, the second top plate portion 532e is disposed closer to the side wall 713 of the side sill outer 521 of the side sill outer 521 and the side sill inner 522.

[0234] As a result, in the width direction X, the height H531 of the first hat component 531 is shorter than the height H532 of the second hat component 532.

[0235] In particular, in the first modified example of the second embodiment, the second top plate portion 532e is located outside in the width direction X of the flanges 711, 721; 715, 725 which are the boundaries between the side sill outer 521 and the side sill inner 522 in the width direction X.

[0236] This layout increases the space between the second top plate portion 532e and the side sill inner 522 (the space inside the second hat member 532). As a result, the amount of impact energy that can be absorbed during a side collision by the pair of second vertical wall portions 532c, 532d collapsing can be increased. Furthermore, during a side collision, the first hat member 531 is first collapsed, and then the second hat member 532 is collapsed, thereby absorbing the impact load from the width direction X in order, starting with the members disposed on the outer side in the width direction X. This smooth impact absorption operation increases the efficiency with which the impact absorbing member 530 absorbs impact energy.

[0237] [Second Modification of Second Embodiment] Figure 11 is a schematic cross-sectional view showing a main portion of a second modification of the second embodiment of the present disclosure. In the second embodiment, a configuration in which the first top plate portion 531e is in contact with the side sill 515 has been mainly described. However, as shown in the second modification of Figure 11, the first top plate portion 531e may be sufficiently spaced apart from the side sill 515. More specifically, the first top plate portion 531e is adjacent to the side wall 713 of the side sill outer 521 but is spaced apart from this side wall 713.

[0238] With this configuration, vibration noise caused by contact between the first top plate portion 531e and the side sill outer 521 can be suppressed, and the impact load from the side sill outer 521 during a side collision can be transmitted to the impact absorbing member 530 along with the crushing of the side sill outer 521. Furthermore, it is not necessary to join the impact absorbing member 530 to both the side sill inner 522 and the side sill outer 521, which reduces the number of steps required to attach the impact absorbing member 530 to the side sill 515.

[0239] The first top plate portion 531e is preferably arranged parallel to the side wall 713, in that the impact load from the side wall 713 of the side sill outer 521 is received by the entire first top plate portion 531e.

[0240] [Third Modification of Second Embodiment] Figure 12 is a schematic cross-sectional view showing a main portion of a third modification of the second embodiment of the present disclosure. In the second embodiment, the second flanges 532a, 532b are joined only to the side wall 723 of the side sill inner 522. However, as in the third modification shown in Figure 12, the second flanges 532a, 532b may also be joined to portions of the side sill 515 other than the side wall 723.

[0241] In the third modified example of the second embodiment, the pair of second flanges 532a, 532b are joined to the side wall 723 of the side sill inner 522 and the pair of walls, that is, the upper wall 722 and the lower wall 724, by the joining method described above.

[0242] The second flanges 532a, 532b are each formed in a shape that follows the portions of the side sill inner panel 522 where the second flanges 532a, 532b face each other. In the third modified example of the second embodiment, each of the second flanges 532a, 532b has a shape in which the middle portion in the height direction Z is curved (bent). The second flanges 532a, 532b only need to be joined to at least a portion of the side wall 723, the upper wall 722, and the lower wall 724, and do not necessarily have to be joined to, for example, the connection portion (ridge portion) between the side wall 723 and the upper wall 722 or the connection portion (ridge portion) between the side wall 723 and the lower wall 724.

[0243] According to the configuration of the third modified example of the second embodiment, the second flanges 532a, 532b are joined to the upper wall 722 and the lower wall 724 in addition to the side wall 723 of the side sill inner 522. This increases the bonding strength between the second hat member 532 and the side sill 515. As a result, even when a strong impact acts on the side sill 515 during a side collision, the second hat member 532 is prevented from coming off the side sill 515, and the impact absorbing effect of the impact absorbing member 530 can be more reliably achieved.

[0244] [Fourth Modification of Second Embodiment] Figure 13 is a schematic cross-sectional view showing a main portion of a fourth modification of the second embodiment of the present disclosure. In the embodiment, the second top plate portion 532e is parallel to the height direction Z (the side walls 713, 723 of the side sill 515). However, as shown in Figure 13, the second top plate portion 532e may be disposed at an angle with respect to the height direction Z (the side walls 713, 723 of the side sill 515).

[0245] For example, as shown in FIG. 13 , the second top plate portion 532e may be inclined downwardly so as to extend outward in the width direction X, or may be inclined downwardly so as to extend inward in the width direction X. The inclination angle θ of the second top plate portion 532e with respect to the height direction Z is not particularly limited, but a value of 45 degrees or less is preferable because it allows the second top plate portion 532e to more reliably absorb the impact during a side collision. The inclination angle θ may be 30 degrees or less, or may be 15 degrees or less. In this case, as shown in FIG. 13 , the first top plate portion 531e may be disposed parallel to the second top plate portion 532e, may be inclined relative to the second top plate portion 532e, or may be parallel to the side walls 713, 723 of the side sill 515.

[0246] As described above, in the fourth modified example of the second embodiment, the second top panel portion 532e is inclined relative to the height direction. With this configuration, for example, even if the side sill 515 collides obliquely with a pole fixed to the ground, the impact from the pole can be more reliably absorbed by the second hat component. Furthermore, the height position of the first hat component 531 can be changed without changing the fixed positions between the second flanges 532a and 532b and the side sill 515. Therefore, the layout of the first hat component 531 can be changed with a slight design change, thereby increasing the design freedom of the impact absorbing component 530.

[0247] 14 is a schematic cross-sectional view showing a main portion of a fifth modification of the second embodiment of the present disclosure. In the embodiment, the second top plate portion 532e has a flat cross-section. However, as shown in FIG. 14 , the second top plate portion 532e may have a plurality of ridges 541a, 541b, 541c, and 541d in the cross-section, which are formed by changing the position in the width direction X at a midpoint in the height direction Z.

[0248] In the fifth modification of the second embodiment, the second top plate portion 532e has a shape that is concave inward in the width direction X (concave so as to be spaced apart from the first top plate portion 531e) due to the formation of the bead 541. The depth H541 of the bead 541 is not particularly limited, and may be, for example, ½ or less, ⅓ or less, or ¼ or less of the height H532 of the second hat component 532.

[0249] The bead 541 is disposed, for example, in the center of the second top plate portion 532e in the height direction Z. The bead 541 forms a recess (hat-shaped portion) in cross section. The bead 541 may have a symmetrical shape or an asymmetrical shape in the height direction Z. The bead 541 has multiple (four in the fifth modified example) ridge portions 541a, 541b, 541c, and 541d formed therein.

[0250] Each of the ridges 541a, 541b, 541c, and 541d is a portion that is curved in an arc shape in cross section and has the function of increasing the amount of impact energy absorbed by the second hat component 532 during impact absorption. The radius of curvature of each of the ridges 541a, 541b, 541c, and 541d in cross section is approximately several mm to several tens of mm.

[0251] As described above, according to the configuration of the fifth modified example of the second embodiment, in addition to the second ridge portions 532f, 532g, 532h, and 532i, the second hat component 532 has the ridge portions 541a, 541b, 541c, and 541d formed by the bead 541. This allows the second hat component 532 to have more ridge portions, and during a side collision, the action of the numerous ridge portions 532f to 532i and 541a to 541d in the impact absorbing component 530 can increase the efficiency of absorbing impact energy when the second hat component 532 deforms.

[0252] In the fifth modified example of the second embodiment, the bead 541 having a concave shape is provided on the second top plate portion 532e. However, this is not necessarily the case. For example, the bead may have a convex shape on the second top plate portion 532e toward the side sill outer 521. Furthermore, the bead may be formed in a shape that convex toward the upper or lower side of the pair of second vertical wall portions 532c, 532d. Furthermore, the bead may be formed on the first top plate portion 531e of the first hat member 531 and have a shape that convex toward the inside or outside in the width direction X.

[0253] The beads may be formed in a shape that convexly extends upward or downward on the pair of first vertical wall portions 531c, 531d. More specifically, for example, as shown in FIG. 15 , which is a drawing of a fifth modified example of the second embodiment, a plurality of concave beads 542 extending from the base end side to the tip end side of the first hat component 531 may be formed intermittently in the front-to-rear direction Y on the first vertical wall portions 531c, 531d. Each bead 542 extends from the first top plate portion 531e to the corresponding first flange 531a, 531b. Each bead 542 is formed in a concave shape when viewed in the width direction X and has a plurality (e.g., four) ridge portions 542a, 542b, 542c, and 542d. The provision of these ridges 542a, 542b, 542c, and 542d increases the efficiency with which the first hat component 531 absorbs impact energy before being crushed during a side collision. Note that beads similar to the beads 542 may be formed on the pair of second vertical wall portions 532c and 532d of the second hat component 532.

[0254] 16 is a schematic cross-sectional view showing a main portion of a sixth modified example of the second embodiment of the present disclosure. In the sixth modified example of the second embodiment, in addition to the configuration of the second embodiment, a second reinforcing member 552 is provided in the impact absorbing member 530.

[0255] The second reinforcing member 552, also called a patch, may be formed from the same material as the second hat member 532 or the first hat member 531, or may be formed from a different material than these hat members 531, 532.

[0256] In a sixth modified example of the second embodiment, the second reinforcing member 552 is a plate-shaped member and is joined to the second hat member 532. The second reinforcing member 552 may be formed over the entire area where the second hat member 532 is located in the front-rear direction Y, or may be formed only over a portion of the area. The second reinforcing member 552 is disposed so as to be surrounded by the second hat member 532. The second reinforcing member 552 includes a second base 552a joined along the inner surface of the second top plate portion 532e, and a pair of second flanges 552b, 552c extending from both ends of the second base 552a in cross section and aligned along the inner surfaces of the pair of second vertical wall portions 532c, 532d. The second flanges 552b, 552c may be joined to the inner surfaces of the pair of second vertical wall portions 532c, 532d. The method of joining the second reinforcing member 552 to the second hat member 532 is the same as the joining method described above.

[0257] As described above, the provision of the second reinforcing member 552 reinforces the second top plate portion 532e. This allows the second top plate portion 532e and the second reinforcing member 552 to cooperate to suppress out-of-plane deformation of the pair of second vertical wall portions 532c, 532d. This allows the second hat member 532 to more reliably absorb impact energy during a side collision. While the sixth modification of the second embodiment has been described with reference to an example in which the second reinforcing member 552 is arranged along the inner side of the second top plate portion 532e in the width direction X, this is not essential. The second reinforcing member 552 may also be arranged along the outer side of the second top plate portion 532e in the width direction X. Furthermore, a plate-shaped reinforcing member similar to the second reinforcing member 552 may be arranged along the upper or lower surface of at least one of the second vertical wall portions 532c, 532d.

[0258] As shown in FIG. 17 , which is a modification of the sixth modification of the second embodiment, a first reinforcing member 551 may be disposed on the first hat component 531. The first reinforcing member 551 is also called a patch and may be formed of the same material as the second hat component 532 or the first hat component 531, or may be formed of a different material from these hat components 531, 532. The first reinforcing member 551 is a plate-shaped member and is joined to the first hat component 531. The first reinforcing member 551 may be formed over the entire area of ​​the first hat component 531 in the front-rear direction Y, or may be formed only in a portion of the area. The first reinforcing member 551 is disposed so as to be surrounded by the first hat component 531. The first reinforcing member 551 includes a first base 551a that is joined to the inner surface of the first top plate portion 531e and a pair of first flanges 551b, 551c that extend from both ends of the first base 551a in cross section and are aligned along the inner surfaces of the pair of first vertical wall portions 531c, 531d. The first flanges 551b, 551c may be joined to the inner surfaces of the pair of first vertical wall portions 531c, 531d. The joining method between the first reinforcing member 551 and the first hat member 531 is the same as the joining method described above. Note that, in this modified example, the first reinforcing member 551 is aligned along the inner side of the first top plate portion 531e in the width direction X, but this is not necessarily the case. The first reinforcing member 551 may also be aligned along the outer side of the first top plate portion 531e in the width direction X. Furthermore, a plate-shaped reinforcing member similar to the first reinforcing member 551 may be disposed along the upper surface or the lower surface of at least one of the first vertical wall portions 531c, 531d.

[0259] As described above, the first top plate portion 531e can be reinforced by providing the first reinforcing member 551. This makes it possible to suppress out-of-plane deformation of the pair of first vertical wall portions 531c, 531d through cooperation between the first top plate portion 531e and the first reinforcing member 551. This makes it possible to more reliably exhibit the impact energy absorption effect of the first hat member 531 in the event of a side collision.

[0260] Note that either the first reinforcing member 551 or the second reinforcing member 552 may be omitted. Furthermore, the second reinforcing member 552 may be spaced apart from the second top plate portion 532e. In this case, the second hat member 532 has two closed cross-sectional portions separated by the second reinforcing member 551, which can further increase the efficiency of absorbing impact energy during a side collision. Furthermore, the first reinforcing member 551 may be spaced apart from the first top plate portion 531e. In this case, the first hat member 531 has two closed cross-sectional portions separated by the first reinforcing member 551, which can further increase the efficiency of absorbing impact energy during a side collision.

[0261] 18 is a schematic cross-sectional view showing a main portion of a seventh modification of the second embodiment of the present disclosure. In the embodiment, the first vertical wall portions 531c, 531d of the first hat component 531 have a configuration in which the distance between the first vertical wall portions 531c, 531d continuously narrows as the distance between the first vertical wall portions 531c, 531d progresses outward in the width direction X. On the other hand, in the seventh modification of the second embodiment, the first vertical wall portions 531c, 531d of the first hat component 531 are formed to have an overall constricted shape in cross section.

[0262] The pair of first vertical wall portions 531c, 531d have base end side portions 531c1, 531d1, ridge portions 531c2, 531d2 connected to the base end side portions 531c1, 531d1, and tip end side portions 531c3, 531d3 connected to the base end side portions 531c1, 531d1 via the ridge portions 531c2, 531d2.

[0263] The distance between the base end portions 531c1, 531d1 narrows as they move outward in the width direction X. The ridge portions 531c2, 531d2 are curved portions located midway along the first hat component 531 in the width direction X. The distance between the tip end portions 531c3, 531d3 widens as they move outward in the width direction X.

[0264] As described above, according to the seventh modification of the second embodiment, the first hat component 531 has the ridges 531c2 and 531d2 in addition to the first ridges 531f, 531g, 531h, and 531i. This provides the first hat component 531 with more ridges, and during a side collision, the action of the numerous ridges in the impact-absorbing member 530 increases the efficiency with which the first hat component 531 absorbs impact energy as it deforms. Furthermore, when the first hat component 531 is crushed during a side collision, deformation occurs such that the ridges 531c2 and 531d2 come into contact with each other, forming two closed cross-sectional portions in the first hat component 531, separated by the contact point between the ridges 531c2 and 531d2. This increases the number of closed cross-sectional portions in the first hat component 531, thereby increasing the efficiency with which the impact energy is absorbed. Furthermore, by changing the positions of the ridge lines 531c2 and 531d2 in the width direction X, the deformation mode of the first hat component 531 during a side collision can be adjusted.

[0265] [Eighth Modification of Second Embodiment] Figure 19 is a schematic cross-sectional view showing a main portion of an eighth modification of the second embodiment of the present disclosure. In the embodiment, the second flanges 532a, 532b and the first flanges 531a, 531b extend outward in the height direction Z relative to the corresponding closed cross-sectional portions 562, 561. However, this is not necessarily the case. As shown in Figure 19, for example, the second flanges 532a, 532b may be arranged to face inward of the second closed cross-sectional portion 562. Furthermore, the first flanges 531a, 531b may be arranged to face inward of the first closed cross-sectional portion 561.

[0266] 20 is a schematic cross-sectional view showing a main portion of a ninth modification of the second embodiment of the present disclosure. In the embodiment, the shock absorbing member 530 is formed using two hat members 531 and 532. However, this is not necessarily the case. For example, the shock absorbing member 530 may be formed using n hat members (n is a natural number equal to or greater than 3).

[0267] In the ninth modified example of the second embodiment, an impact absorbing member 530 is formed of three hat members 531, 532, and 533. That is, in the ninth modified example of the second embodiment, the impact absorbing member 530 includes a third hat member 533 (nth hat member) in addition to a second hat member 532 and a first hat member 531.

[0268] The first top plate portion 531e of the first hat member 531 is spaced apart from the side sill outer member 521 in the width direction X. The height H533 of the third hat member 533 (the length of the third hat member 533 in the width direction X) is not particularly limited and is set appropriately depending on the height H532 of the second hat member 532 and the height H531 of the first hat member 531.

[0269] The third hat member 533 comprises a pair of third flanges 533a, 533b joined to the first top plate portion 531e, a pair of third vertical wall portions 533c, 533d extending from the pair of third flanges 533a, 533b, and a third top plate portion 533e connecting the pair of third vertical wall portions 533c, 533d.

[0270] Furthermore, in this modified example, the third hat component 533 includes a pair of base end side third ridge portions 533f, 533g and a pair of tip end side third ridge portions 533h, 533i.

[0271] The pair of third flanges 533a, 533b are joined by the above-described joining method to the first top plate portion 531e of the first hat component 531. The third flanges 533a, 533b do not have to be joined directly to the first top plate portion 531e, and may be joined to the first top plate portion 531e via a patch (reinforcing member).

[0272] The lengths of the third flanges 533a, 533b are not particularly limited, but it is preferable that they do not extend beyond the first top plate portion 531e in the height direction Z in order to reduce the weight of the third hat component 533. Furthermore, end faces 533j, 531k of the third flanges 533a, 533b face the height direction Z and do not face the first hat component 531 in the height direction Z. The third flanges 533a, 533b may contact the first top plate portion 531e of the first hat component 531 but may not contact the tip-side first ridge portions 531h, 531i. With the third flanges 533a, 533b arranged as described above, the vertical wall portions 533c, 533d of the third hat member 533 are arranged so that the vertical wall portions 531c, 531d of the first hat member 531 are outside the region extending in the longitudinal direction of the vertical wall portions 531c, 531d. With this layout of the third hat member 533, when an impact load acts on the third hat member 533, the third flanges 533a, 533b can firmly support the vertical wall portions 533c, 533d. As a result, more impact energy can be absorbed by promoting deformation of the vertical wall portions 533c, 533d between the base-side third ridge portions 533f, 533g and the tip-side third ridge portions 533h, 533i.

[0273] The upper third flange 533a extends upward from the upper third vertical wall portion 533c, and the lower third flange 533b extends downward from the lower third vertical wall portion 533d. These third flanges 533a, 533b are spaced apart from each other, and the third hat member 533 has a shape in which the inner side in the width direction X is open toward the side sill inner 522. As such, it is preferable that the third hat member 533 is joined only to the first top plate portion 531e of the first hat member 531, and that no other part of the impact absorbing member 530 is disposed between the third flanges 533a, 533b in the height direction Z. This configuration allows the impact absorbing member 530 to be made lighter. Furthermore, when spot welding the first hat component 531 and the third hat component 533, the third flanges 533a, 533b, which are disposed outward in the height direction Z from the pair of third vertical wall portions 533c, 533d, and the first top plate portion 531e can be sandwiched and welded using a welding machine. As described above, in the ninth modification of the second embodiment, the outward third flanges 533a, 533b are disposed outward in the height direction Z from the pair of third vertical wall portions 533c, 533d. The lower end of the upper third flange 533a and the upper end of the lower third flange 533b are connected to the third vertical wall portions 533c, 533d via the base-end-side third ridge portions 533f, 533g.

[0274] The base-side third ridge portions 533f, 533g are portions that are curved in an arc shape in cross section and have the function of increasing the amount of impact energy absorbed by the third hat component 533 during impact absorption. The radius of curvature of the base-side third ridge portions 533f, 533g in cross section is approximately several millimeters to several tens of millimeters. The radius of curvature of the base-side third ridge portions 533f, 533g may be the same as the radius of curvature of the base-side first ridge portions 531f, 531g of the first hat component 531, may be less than the radius of curvature of the base-side first ridge portions 531f, 531g, or may be greater than the radius of curvature of the base-side first ridge portions 531f, 531g.

[0275] The pair of third vertical wall portions 533c, 533d of the third hat member 533 are arranged along the width direction X, and the distance between the pair of third vertical wall portions 533c, 533d increases toward the side sill inner 522. This layout of the pair of third vertical wall portions 533c, 533d allows the third hat member 533 to receive in a balanced manner the impact load acting inward in the width direction X from the side sill outer 521. This increases the amount of impact energy absorbed by the impact absorbing member 530 during a side collision. Note that the pair of third vertical wall portions 533c, 533d may be arranged parallel to (horizontally with) the width direction X, or the distance between the pair of third vertical wall portions 533c, 533d may decrease toward the side sill inner 522.

[0276] The upper third vertical wall portion 533c and the lower third vertical wall portion 533d are connected to the third top plate portion 533e via third ridge portions 533h and 533i on the tip side.

[0277] The third tip ridges 533h, 533i are arc-shaped in cross section and have the function of increasing the amount of impact energy absorbed by the third hat component 533 during impact absorption. The radius of curvature of the third tip ridges 533h, 533i in cross section is approximately several mm to several tens of mm.

[0278] The third top plate portion 533e is the portion of the impact absorbing member 530 that is first subjected to an impact load during a side collision. The third top plate portion 533e suppresses out-of-plane deformation of the pair of third vertical wall portions 533c, 533d connected to the third top plate portion 533e, such as the pair of third vertical wall portions 533c, 533d collapsing inward of the third vertical wall portions 533c, 533d.

[0279] In this embodiment, the third top plate portion 533 e is in contact with the side wall 713 of the side sill outer 521 , but is not joined to the side wall 713 of the side sill outer 521 .

[0280] With such a preferable configuration, the work of installing the impact absorbing member 530 inside the side sill 515 is easy. This is because the work of joining the third top plate portion 533e to the side wall 713 of the side sill outer 521 is not necessary. If the third top plate portion 533e were to be joined to the side wall 713 of the side sill outer 521 by welding, a welding machine would need to be sandwiched between the third top plate portion 533e and the side wall 713. This makes the work of installing the impact absorbing member 530 inside the side sill 515 time-consuming. This kind of time-consuming work exists whether the type of welding is spot welding or laser welding.

[0281] Furthermore, with this preferred configuration, in the event of a side collision of the vehicle, the impact absorbing member 530 can undergo three-stage collapse by the three closed cross-sectional portions 563, 561, 562 collapsing in sequence while the influence of deformation of the side sill outer 521 is reduced, thereby increasing the efficiency of absorbing impact energy. In other words, in the event of a side collision of the vehicle, the impact absorbing member 530 can deform and absorb impact while being less influenced by deformation of the side sill outer 521. This allows the impact absorbing performance of the impact absorbing member 530 to be exhibited more effectively.

[0282] The third top plate portion 533e may be spaced apart from the side wall 713 of the side sill outer 521 to such an extent that it does not come into contact with the side wall 713 even when the vehicle is vibrating while traveling, or may be spaced apart to such an extent that it does not come into contact with the side wall 713 of the side sill outer 521 even when the vehicle is vibrating while traveling.

[0283] In this way, if the top plate portion 533e is spaced from the side sill outer 521, deformation of the side sill outer 521 due to impact transmission from the side sill outer 521 to the impact absorbing member 530 and the side sill inner 522 can be suppressed in the event of a relatively minor side collision of the vehicle. When a relatively minor side collision of the vehicle occurs, impact acts on the side sill outer 521, but the amount of impact transmitted from the side sill outer 521 to the impact absorbing member 530 is small. Therefore, the amount of impact transmitted to the side sill inner 522 via the impact absorbing member 530 is small. In this case, the amount of deformation of the side sill 515 is small, thereby suppressing a deterioration in the vehicle's driving performance (such as straight-line running performance). Furthermore, while repairs are required to the side wall 713 and the like of the side sill outer 521 when repairing the vehicle, repairs to the impact absorbing member 530 and the side sill inner 522 are not required, thereby reducing the effort and cost required for vehicle maintenance. On the other hand, when a large side collision occurs to the vehicle, the impact is transmitted from the side sill outer 521 to the side sill inner 522 via the impact absorbing member 530, thereby enabling efficient impact energy absorption through deformation of the impact absorbing member 530 and the side sill inner 522.

[0284] The third top plate portion 533e is preferably arranged parallel to the side wall 713 so that the entire third top plate portion 533e receives the impact load from the side wall 713 of the side sill outer panel 521. The third top plate portion 533e connects the pair of third vertical wall portions 533c, 533d. The third top plate portion 533e is preferably arranged parallel to the second top plate portion 532e and the first top plate portion 531e so that the efficiency of absorbing impact energy acting in the width direction X during a side collision can be increased.

[0285] With the above configuration, a pair of vertical wall portions 531c, 531d (a pair of first portions) of the first hat member 531, a pair of vertical wall portions 532c, 532d (a pair of second portions) of the second hat member 532, and a pair of vertical wall portions 533c, 533d (a pair of third portions) of the third hat member 533 cooperate to form a pair of vertical wall portions 545, 546 in the hat-shaped portion 540 of the impact absorbing member 530.

[0286] As described above, in the ninth modification of the second embodiment, the impact absorbing member 530 includes an nth hat member (n is a natural number equal to or greater than 3) formed in a hat-shaped cross section. The nth hat member (third hat member 533) includes a pair of nth flanges (third flanges 533a, 533b), a pair of nth vertical wall portions (third vertical wall portions 533c, 533d) extending from the pair of nth flanges, and an nth top plate portion (third top plate portion 533e) connecting the pair of nth vertical wall portions. The hat members (hat members 531 to 533) are arranged along the width direction X, and the top plate portions and the pair of flanges are joined to each other in adjacent hat members (the second hat member 532 and the first hat member 531; the first hat member 531 and the third hat member 533).

[0287] In this way, by forming the impact absorbing member 530 from three or more hat components, more ridges can be provided in the impact absorbing member 530. As a result, during a side collision, the action of the numerous ridges in the impact absorbing member 530 can increase the efficiency of impact energy absorption when the closed cross-sectional shapes of the second hat component 532, the first hat component 531, and the third hat component 533 deform. In particular, because numerous ridges are formed in the third hat component 533, which is the first component in the impact absorbing member 530 to receive the impact load, the amount of impact energy absorbed when the third hat component 533 is crushed can be increased. As a result, the impact energy absorption efficiency of the impact absorbing member 530 can be increased while reducing the weight of the impact absorbing member 530, thereby improving the weight efficiency of impact energy absorption. Furthermore, by adjusting the shape of each hat component 531 to 533, the timing at which each hat component 531 to 533 starts to deform and the manner in which each hat component 531 to 533 deforms during a side collision can be set. This allows the impact absorbing operation of the impact absorbing member 530 during a side collision to be set according to the characteristics of the vehicle (such as the presence or absence of the battery case 600 and the layout of the battery case 600). This allows the vehicle to achieve higher side collision resistance. Furthermore, because the impact absorbing member 530 is formed of multiple members (in this embodiment, the second hat member 532, the first hat member 531, and the third hat member 533), the degree of freedom in designing the shape is higher than when the impact absorbing member 530 is formed of a single member.

[0288] In the ninth modification of the second embodiment, the shock absorbing member 530 is formed of three hat members 531, 532, and 533. However, the shock absorbing member 530 may be formed of four or more hat members. In this case, multiple hat members are lined up along the width direction X, and the top plate portion and a pair of flanges of adjacent hat members are joined to each other. In this case, too, it is preferable that the length of the shock absorbing member 530 in the height direction Z gradually decreases toward the outside in the width direction X. This allows the shock energy caused by the crushing of the shock absorbing member 530 to be efficiently absorbed.

[0289] [Tenth Modification of Second Embodiment] FIG. 21 is a schematic cross-sectional view showing a main portion of a tenth modification of the second embodiment of the present disclosure. In the second embodiment, the pair of second flanges 532a, 532b of the impact absorbing member 530 are joined to the side sill inner panel 522. On the other hand, in the tenth modification of the second embodiment shown in FIG. 21 , the first top plate portion 531e is joined to the side sill inner panel 522 by the joining method described above. That is, in the tenth modification of the second embodiment, the impact absorbing member 530 is disposed symmetrically in the width direction X with respect to the impact absorbing member 530 in the embodiment. Furthermore, the pair of second flanges 532a, 532b of the second hat member 532 are joined to the reinforcing plate 580 by the joining method described above. The reinforcing plate 580 is formed, for example, from the same material as the first hat member 531 or the second hat member 532 and joins the second flanges 532a, 532b to each other.

[0290] In the tenth modified example of the second embodiment, the second hat member 532 is positioned adjacent to the side sill outer member 521, and the first hat member 531 is positioned closer to the side sill inner member 522 than the side sill outer member 521 and the side sill inner member 522.

[0291] In this way, by joining the first hat member 531 of the impact absorbing member 530 to the side sill inner panel 522, the efficiency of absorbing impact energy during a side collision can be increased.

[0292] Furthermore, by positioning the second hat member 532 adjacent to the side sill outer member 521 and positioning the first hat member 531 closer to the side sill inner member 522, the efficiency of absorbing impact energy during a side collision can also be increased.

[0293] 22 is a schematic cross-sectional view showing a main portion of an eleventh modification of the second embodiment of the present disclosure. In the embodiment, the shock absorbing member 530 is disposed inside the side sill 515. However, this is not necessarily the case. For example, the shock absorbing member 530 may be disposed to the side of the side sill 515 in the width direction X.

[0294] In this modified example, the impact absorbing member 530 is disposed on the vehicle inner side with respect to the side sill 515 in the width direction X. The second flanges 532a, 532b of the impact absorbing member 530 may be joined to the side wall 600b of the battery case 600 or the like by the joining method described above, or the first top plate portion 531e may be joined to the side wall 723 of the side sill inner panel 522 or the like by the joining method described above. In the impact absorbing member 530, it is sufficient that at least one of the first top plate portion 531e and the second flanges 532a, 532b is joined to the corresponding battery case 600 and side sill inner panel 522. In this way, even when the impact absorbing member 530 is disposed between the side sill 515 and the battery case 600 on the side of the side sill 515, the impact absorbing member 530 can absorb impact energy by being crushed during a side collision. In this modified example, the width direction end 600a of the battery case 600 is disposed at the upper part of the battery case 600, but it may also be disposed at the lower part of the battery case 600. Note that, in this modified example, the shock absorbing member 530 is disposed between the side sill 515 and the battery case 600, but this is not the only option. The shock absorbing member 530 may be disposed near the side sill 515, for example, below the side sill 515.

[0295] Although this modification has been described using an example of a configuration similar to that of the impact absorbing member 530 of the second embodiment, the impact absorbing member 530 described in each modification may be used instead. In this case, too, the second flanges 532 a, 532 b and the first top plate portion 531 e of the impact absorbing member 530 are joined to the side sill 515, the battery case 600, or a member surrounding the impact absorbing member 530.

[0296] As shown in FIG. 23 for explaining a modified example of the eleventh modified example of the second embodiment, the impact absorbing member 530 may be spaced apart from the side sill 515 .

[0297] 24 is a schematic cross-sectional view showing a main portion of a twelfth modified example of the second embodiment of the present disclosure. In the second embodiment and each of the above-described modified examples, the battery case 600 is disposed so as to contact the floor panel 518. However, this is not necessarily the case. For example, the battery case 600 may be disposed at a position spaced apart from the floor panel 518.

[0298] [Thirteenth Modification of Second Embodiment] In the second embodiment, the tensile strength TS1 (Vickers hardness HV1) of the first hat component 531 is set lower than the tensile strength TS2 (Vickers hardness HV2) of the second hat component 532. However, this is not necessarily the case. The tensile strength TS1 (Vickers hardness HV1) of the first hat component 531 may be set higher than the tensile strength TS2 (Vickers hardness HV1) of the second hat component 532 (TS1 > TS2). That is, the strength of the side sill outer 521 side of the impact absorbing component 530 may be set higher than the strength of the side sill inner 522 side. In this case, the tensile strength TS1 of the first hat component 531 and the tensile strength TS2 of the second hat component 532 may be interchanged.

[0299] With this configuration, the peak of the impact load acting on the first hat component 531 during a side collision is increased, allowing the first hat component 531 to absorb more impact energy.

[0300] In addition, a configuration in which the plate thickness t2 of the second hat component 532 and the plate thickness t1 of the first hat component 531 in the second embodiment are interchanged (t1>t2) can be exemplified. With this configuration, the peak of the impact load acting on the first hat component 531 during a side collision can be increased, allowing the first hat component 531 to absorb more impact energy.

[0301] [Fourteenth Modification of Second Embodiment] Figure 25 is a schematic cross-sectional view showing a main portion of a fourteenth modification of the second embodiment of the present disclosure. Figure 26 is a schematic perspective view showing a main portion of a fourteenth modification of the second embodiment of the present disclosure. In the second embodiment and each modification, the first flanges 531a, 531b of the first hat component 531 are joined to the second top plate portion 532e of the second hat component 532 but are not joined to the distal-side second ridge portions 532h, 532i or the vertical wall portions 532c, 532d. In contrast, as shown in the fourteenth modification of the second embodiment, the first flanges 531a, 531b of the first hat component 531 may also be joined to the distal-side second ridge portions 532h, 532i or the vertical wall portions 532c, 532d of the second hat component 532. In this case as well, the first flanges 531a and 531b are also joined to the second top plate portion 532e.

[0302] In the present fourteenth modification, beads 570 (571, 572) may be formed on the impact absorbing member 530. In the present fourteenth modification, the beads 571, 572 are provided to increase the rigidity (at least one of bending rigidity and torsional rigidity) of the first hat component 531. The bead 571 is formed on one vertical wall portion 531c of the first hat component 531, and the bead 572 is formed on the other vertical wall portion 531d of the first hat component 531. The pair of beads 571, 572 are preferably aligned in the front-to-rear direction Y. The beads 571, 572 are formed by recessing the corresponding vertical wall portions 531c, 531d of the first hat component 531. The beads 571, 572 may be formed by forming the corresponding vertical wall portions 531c, 531d of the first hat component 531 into a shape that is convex in the height direction Z. The dimensions of each bead 571, 572 in the width direction X, the front-rear direction Y, and the height direction Z are not particularly limited as long as they can improve at least one of the bending rigidity and the torsional rigidity of the first hat component 531.

[0303] [Other Modifications of the Second Embodiment] In each of the above-described embodiments and modifications, a separate reinforcing member may be interposed between the impact absorbing member 530 and the floor cross members 516, 517. This reinforcing member is positioned so as to prevent the floor cross members 516, 517 from breaking due to an impact load transmitted from the impact absorbing member 530 to the floor cross members 516, 517 via the side sill 515.

[0304] Furthermore, the impact absorbing member 530 in the above-described embodiment and each modified example may be made of an aluminum alloy, or may be made of a composite material such as CFRP (Carbon Fiber Reinforced Plastics).

[0305] Furthermore, while the above-described embodiments and modifications have been described primarily with reference to a vehicle body having a monocoque structure, this is not necessarily the case. For example, the present disclosure may be applied to a vehicle body having a ladder frame structure.

[0306] The present disclosure is widely applicable to side sill structures and automobile undercarriages.

[0307] DESCRIPTION OF SYMBOLS 14 Side sill structure 15 Side sill 16, 17 Floor cross member 21 Side sill outer 22 Side sill inner 23 Closed cross-sectional space 30 Impact absorbing member 31 First hat member 32 Second hat member 40 Hat-shaped portion 41 First top plate portion 42 Second top plate portion 45, 46 Pair of vertical wall portions 45a, 46a Pair of first portions 45b, 46b Pair of second portions 47, 48 Pair of flanges 61 First closed cross-sectional portion 62 Second closed cross-sectional portion 70 Bead 100 Battery case 101 Battery 514 Side sill structure 515 Side sill 516, 517 Floor cross member 530 Impact absorbing member 521 Side sill outer 522 Side sill inner 523 Closed cross-sectional space 531 First hat member 532 Second hat member 540 Hat-shaped portion 531e First top plate portion 532e Second top plate portion 545, 546 Pair of vertical wall portions 531c, 531d Vertical wall portions (pair of first portions) 532c, 532d Vertical wall portions (pair of second portions) 532a, 532b Pair of flanges 561 First closed cross-sectional portion 562 Second closed cross-sectional portion 570 Bead 600 Battery case 601 Battery X Width direction Y Front-rear direction Z Height direction

Claims

a side sill including a side sill outer and a side sill inner disposed on the vehicle width direction inner side of the side sill outer, the side sill extending in a vehicle longitudinal direction and forming a closed cross-sectional space in a cross section perpendicular to the vehicle longitudinal direction; an impact absorbing member formed of a plurality of members; Equipped with In the cross section, the impact absorbing member includes a hat-shaped portion having a first top plate portion extending in a vehicle height direction and a pair of vertical wall portions extending along the vehicle width direction from both ends of the first top plate portion in the vehicle height direction, and a second top plate portion arranged apart from the first top plate portion in the vehicle width direction and connecting the pair of vertical wall portions, the second top plate portion divides an inner space of the hat-shaped portion in the vehicle width direction, thereby forming a first closed cross-sectional portion including the first top plate portion and a second closed cross-sectional portion adjacent to the first closed cross-sectional portion in the vehicle width direction, A side sill structure, wherein the impact absorbing member is spaced apart from the side sill outer, or is in contact with the side sill outer without being joined to the side sill outer. 　 The impact absorbing member is formed by combining a first hat member and a second hat member, 2. The side sill structure according to claim 1, wherein a top plate portion of the first hat member forms the first top plate portion, a top plate portion of the second hat member forms the second top plate portion, and a pair of first portions that are a pair of vertical wall portions of the first hat member and a pair of second portions that are a pair of vertical wall portions of the second hat member cooperate to form the pair of vertical wall portions. 　 The side sill structure according to claim 2 , wherein the first hat member has a lower Vickers hardness than the second hat member. 　 The side sill structure according to claim 2 , wherein the first hat member has a Vickers hardness higher than that of the second hat member. 　 The side sill structure according to claim 2 , wherein a thickness of the first hat member is smaller than a thickness of the second hat member. 　 The side sill structure according to claim 2 , wherein a thickness of the first hat member is greater than a thickness of the second hat member. 　 Regarding the Vickers hardness HV1 and the plate thickness t1 of the first hat member and the Vickers hardness HV2 and the plate thickness t2 of the second hat member, 180≦HV1, HV2≦780, 0.8 mm≦t1 t2≦2.3 mm, HV1 x t1 < HV2 x t2 The side sill structure according to claim 2, 　 The side sill structure according to claim 2 , wherein the impact absorbing member includes a hat member that forms the hat-shaped portion, and a top plate member that forms the second top plate portion. 　 Regarding the Vickers hardness HV2 and plate thickness t2 of the hat member and the Vickers hardness HV1 and plate thickness t1 of the top plate member, 180≦HV1, HV2≦780, 0.8 mm≦t1 t2≦2.3 mm, HV1 x t1 < HV2 x t2 The side sill structure according to claim 8, 　 The side sill structure according to claim 1 , wherein the second top plate portion of the impact absorbing member has a shape that is convex toward the first top plate portion in the cross section. 　 The side sill structure according to claim 1 , wherein the impact absorbing member is made of a steel plate. 　 The hat-shaped portion includes a pair of flanges extending from the pair of vertical wall portions, The side sill structure according to claim 1 , wherein the pair of flanges are joined to the side sill inner member. 　 The side sill structure according to claim 1 , wherein a bead is formed on the impact absorbing member. 　 The side sill structure according to claim 1 , wherein the impact absorbing member is supported by the side sill within the closed cross-sectional space, or is disposed laterally of the side sill in the vehicle width direction. 　 the first hat member includes a pair of first flanges, a pair of first vertical wall portions extending from the pair of first flanges, and the first top plate portion connecting the pair of first vertical wall portions, 3. The side sill structure according to claim 2, wherein the second hat member includes a pair of second flanges, a pair of second vertical wall portions extending from the pair of second flanges, and the second top plate portion connecting the pair of second vertical wall portions and joined to the pair of first flanges. 　 The side sill structure according to claim 2 , further comprising a reinforcing member in at least one of the hat members. 　 the impact absorbing member further includes an nth hat member (n is a natural number of 3 or more) formed in a hat shape in the cross section, the nth hat member includes a pair of nth flanges, a pair of nth vertical wall portions extending from the pair of nth flanges, and an nth top plate portion connecting the pair of nth vertical wall portions, The side sill structure according to claim 2 , wherein the hat members are arranged side by side in the vehicle width direction, and the top plate portion and the pair of flanges of the hat members adjacent to each other are joined to each other. 　 The side sill structure according to claim 1 , wherein the impact absorbing member is made of a steel plate. 　 The side sill structure according to any one of claims 1 to 18 is provided, The side sills are provided in pairs spaced apart in the vehicle width direction, The vehicle further includes a plurality of cross members disposed between the pair of side sills and extending in the vehicle width direction, An undercarriage of an automobile, wherein the impact absorbing member is provided inside each of the pair of side sills or on the inner side in the vehicle width direction.

20. The vehicle undercarriage according to claim 19, further comprising a battery case disposed below the cross member and housing a battery.

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