Vehicle body structure

Abstract

A vehicle body structure 1 includes a side sill 2, a floor cross member 3 serving as a first member joined to the side sill 2, and a battery case 4 serving as a second member adjacent to the side sill 2. The second member is the battery case 4 or a ladder frame 9. The side sill 2 includes a side sill inner 10 that is joined to the first member and is adjacent to the second member, a side sill outer 20 that is located on the vehicle-width-direction outer side of the side sill inner 10, and a first reinforcement material 30 and a second reinforcement material 40 that are located in an internal space 2a. The first reinforcement material 30 is aligned in the vehicle width direction with one of the first member and the second member, extended in the vehicle length direction, and constituted of an extrusion material having a plurality of closed cross sections 30a aligned in the vehicle width direction. The second reinforcement material 40 has a plate-form part 40a that is aligned with the other of the first member and the second member in the vehicle width direction and that extends in the vehicle width direction.

Description

Body structure

[0001] The present disclosure relates to a vehicle body structure equipped with a side sill.

[0002] Conventionally, there has been a demand for improved occupant safety in vehicles, and for this purpose, efforts have been made to improve collision safety performance by improving the strength of the vehicle body. In particular, side collisions (hereinafter also referred to as lateral collisions) tend to inflict a strong impact on the vehicle interior, and high impact absorption performance is required for side collisions. In other words, when the vehicle spins and an object such as a pole hits the side of the vehicle body, it is necessary to absorb the impact energy and protect the vehicle interior. Meanwhile, against the backdrop of worsening issues such as global warming, efforts to improve automobile fuel efficiency are accelerating. It is known that reducing the weight of the vehicle body is an effective way to improve fuel efficiency.

[0003] Patent Document 1 discloses a side sill including a side sill outer, a side sill inner, and a reinforcing member. The reinforcing member is made of an extruded material having a plurality of rectangular closed cross sections and is housed in an internal space defined by the side sill outer and the side sill inner. The reinforcing member extends in the vehicle length direction with the plurality of rectangular closed cross sections aligned in the vehicle width direction. The rectangular cross sections of the extruded material are expected to be crushed sequentially from the outer side in the vehicle width direction during a side collision, thereby ensuring the side sill's impact energy absorption capacity.

[0004] Japanese Patent Application Laid-Open No. 2021-66315

[0005] In order to reduce the weight of the vehicle body, it is difficult to increase the size of the extrusion in the vertical direction. If the cross-sectional height of the extrusion is set low, it may not be possible to sufficiently absorb the impact energy depending on the load input position during a side collision. There is still room for improvement in energy absorption performance during a side collision.

[0006] An object of the present disclosure is to achieve both weight reduction of the vehicle body structure and improvement of energy absorption performance.

[0007] One aspect of the present disclosure is a vehicle body structure including: a side sill extending in a vehicle length direction; a floor cross member as a first member joined to the side sill and disposed inward in a vehicle width direction with respect to the side sill; and a second member aligned with the first member in a vehicle height direction, adjacent to the side sill with a gap therebetween, and disposed inward in the vehicle width direction with respect to the side sill, wherein the second member is a battery case that houses a battery or a ladder frame, and the side sill is joined to the first member and adjacent to the second member, and the second member is disposed inward in the vehicle width direction with respect to the side sill. a side sill outer disposed on the outside in the vehicle width direction; a side sill internal space defined by the side sill inner and the side sill outer; a first reinforcing member disposed in the side sill internal space so as to be aligned with one of the first member and the second member in the vehicle width direction, extending in the vehicle length direction, and formed of an extruded member having a plurality of closed cross sections aligned in the vehicle width direction; and one or more second reinforcing members disposed in the side sill internal space so as to be aligned with the other of the first member and the second member in the vehicle width direction, and having a plate-shaped portion extending in the vehicle width direction.

[0008] According to the above configuration, the first reinforcing member and the second reinforcing member are disposed in the interior space of the side sill, the first reinforcing member being aligned in the vehicle width direction with one of the first and second members that are disposed on the inside of the side sill inner panel in the vehicle width direction, and the second reinforcing member being aligned in the vehicle width direction with the other of the first and second members. The first and second members are aligned in the vehicle height direction (vertical direction). Therefore, the first and second reinforcing members are also aligned in the vehicle height direction. The first member is a floor cross member, and the second member is a battery case or a ladder frame, both of which are vehicle body members having sufficient strength to withstand loads.

[0009] For simplicity, let us assume that the first reinforcement is arranged side by side with the first member. During a side collision, the first reinforcement collapses sequentially from the outside in the vehicle width direction to absorb impact energy. As the first reinforcement collapses, it transmits the load to the first member. Because the first member is joined to the side sill, the load is transmitted through the first reinforcement from the early stage of the collision. This allows the deformation load to build up at an early stage, improving the energy absorption performance of the entire vehicle body structure. The first reinforcement extends in the vehicle length direction within the interior space of the side sill. In other words, regardless of the position in the vehicle length direction at which the load during a side collision is input to the side sill, it collides with the first reinforcement and can apply the load to the first member arranged intermittently on the inside. This allows for stable absorption of impact energy. In this example, the second reinforcement is arranged below the first reinforcement. During a side collision, the second reinforcement deforms and transmits the load to the second member arranged on the inside of the side sill in the vehicle width direction. In other words, in addition to transmitting the load from the first reinforcement to the first member, the load is also transmitted from the second reinforcement to the second member, distributing the load path and increasing the reaction force, thereby further improving the energy absorption performance of the entire vehicle body structure. The second reinforcement has a plate-shaped portion extending in the vehicle width direction and vehicle height direction within the side sill internal space, and is selectively arranged in areas where a locally high energy absorption capacity is required in the vehicle length direction. By adopting this structure and arrangement, the ratio of deformation load to weight can be increased when a load is input in the vehicle width direction, allowing the second reinforcement to efficiently absorb impact energy. The same applies when the first reinforcement is arranged sideways with the second member, but in this case, the second reinforcement is arranged above the first reinforcement.

[0010] The first reinforcing member and the second reinforcing member are arranged side by side in the vehicle height direction in the internal space of the side sill. Compared to a case in which the first reinforcing member, which is made of an extrusion extending in the vehicle length direction, is made larger in the vehicle height direction, the weight of the side sill and therefore the vehicle body structure can be reduced. The arrangement of the first reinforcing member and the second reinforcing member is determined in relation to the first member and the second member, which are located more inward in the vehicle width direction than the side sill inner member, so that the entire vehicle body structure can absorb loads input from the outside toward the inside in the vehicle width direction. Therefore, the vehicle body structure can be made lighter while improving its energy absorption performance. Both the first member and the second member are high-strength vehicle body members. Because a load can be applied to these members, the load is input to the high-strength vehicle body members, improving the energy absorption performance of the entire vehicle body structure and making it easier to reduce the weight of the side sill.

[0011] The side sill may include a plurality of the second reinforcing members, and the plurality of second reinforcing members may be arranged at intervals from one another in the vehicle length direction.

[0012] According to the above configuration, the second reinforcing material is locally disposed, and an increase in weight due to the application of the second reinforcing material can be suppressed.

[0013] The plurality of second reinforcing members may be arranged more densely in a central region including the center of gravity of the vehicle in a side view than in end regions that are farther away from the center of gravity of the vehicle in the vehicle length direction.

[0014] Generally, the center of gravity of a vehicle is located in the longitudinal and lateral center of the entire vehicle. If a load is input to the vicinity of the center of gravity during a side collision, the vehicle itself does not rotate much, and all of the collision energy is absorbed by deformation of this area. In other words, a collision near the center of gravity requires higher energy absorption than a collision at another area. With the above configuration, the second reinforcement members are densely arranged around the center of gravity of the vehicle. Therefore, in practice, it is possible to deform the second reinforcement member in addition to the first reinforcement member during a side collision, improving the energy absorption performance of the side sill and, ultimately, the vehicle body structure.

[0015] The first reinforcing material may be arranged so as to be aligned with the first member in the vehicle width direction, the second reinforcing material may be arranged so as to be aligned with the second member in the vehicle width direction, and the first reinforcing material may be arranged above the second reinforcing material.

[0016] According to the above configuration, a structure can be realized in which the first reinforcing member transmits the load to the floor cross member as the first member, and the second reinforcing member transmits the load to the battery case or ladder frame as the second member.

[0017] The first reinforcing member may be joined to at least one of the side sill outer member and the side sill inner member via a bracket.

[0018] According to the above configuration, the first reinforcing member is stably supported by the side sill outer and the side sill inner.

[0019] The first reinforcing material may be made of an aluminum alloy, the second reinforcing material may be molded from the aluminum alloy, and the second reinforcing material may be joined to the upper or lower surface of the first reinforcing material.

[0020] According to the above configuration, because the first reinforcing member and the second reinforcing member are formed from the same metal, they can be easily joined by metallurgical joining such as welding, etc. This allows the side sill to be easily manufactured by joining the first reinforcing member and the second reinforcing member to produce a sub-assembly, and then assembling this sub-assembly to the side sill inner and side sill outer.

[0021] The first reinforcing member may have a protruding portion that protrudes from one end or the other end in the vehicle width direction toward a side in the vehicle height direction on which the second reinforcing member is disposed.

[0022] According to the above configuration, it is possible to prevent a shear load from being input between the first reinforcing material and the second reinforcing material, and to suppress breakage of the first reinforcing material and the second reinforcing material.

[0023] The second reinforcing material may have a pair of flange portions joined to the upper or lower surface of the first reinforcing material, a pair of upright portions as plate-shaped portions extending from each of the pair of flange portions away from the first reinforcing material in the vehicle height direction, and a bottom wall portion connecting the pair of upright portions to each other.

[0024] According to the above configuration, the second reinforcing member and the first reinforcing member form a closed cross-sectional portion extending in the vehicle width direction, which can increase the ratio of deformation load to weight when a load is input in the vehicle width direction.

[0025] The second reinforcement may be formed from steel and may be positioned above or below the first reinforcement at a distance from the first reinforcement.

[0026] According to the above configuration, the second reinforcing member is made of the same material as the side sill inner or side sill outer, which are also made of steel plate, and can be easily joined to these parts by metallurgical joining such as melting. In other words, with this configuration, even if the first reinforcing member and the second reinforcing member are formed of different metals, there is no need to join them, and the side sill and vehicle body structure can be realized.

[0027] The second reinforcing member may be formed of a sheet metal material having one plate-like portion extending in the vehicle height direction and the vehicle width direction, and a stiffening bead provided on the plate-like portion.

[0028] According to the above configuration, since the second reinforcing member is made of a metal plate having a single plate-shaped portion extending in the vehicle height direction and the vehicle width direction, the ratio of deformation load to weight when a load is input in the vehicle width direction can be increased. Since the stiffening bead is provided, the impact energy absorption performance of the second reinforcing member is improved.

[0029] The second reinforcing material may have a top plate portion arranged at a distance downward from the underside of the first reinforcing material, a pair of hanging portions as the plate-shaped portion extending downward from the top plate portion, and a flange portion formed by bending the top plate portion and the pair of hanging portions and joined to the side sill inner or the side sill outer.

[0030] According to the above configuration, the second reinforcing member, together with the side sill inner and outer members, forms a closed cross-section portion extending in the vehicle width direction, which can increase the ratio of deformation load to weight when a load is input in the vehicle width direction.

[0031] According to the present disclosure, it is possible to achieve both a reduction in the weight of the vehicle body structure and an improvement in energy absorption performance.

[0032] 1 is a left side view of a vehicle to which the vehicle body structure according to the first embodiment is applied; a longitudinal cross-sectional view of the vehicle body structure according to the first embodiment; a perspective view of a second reinforcing member according to the first embodiment; a cross-sectional view of the vehicle body structure according to the first embodiment; a cross-sectional view of a vehicle body structure according to a modified example of the first embodiment; a longitudinal cross-sectional view of the vehicle body structure according to the second embodiment; a perspective view of a second reinforcing member according to the second embodiment; a cross-sectional view of the vehicle body structure according to the second embodiment; a longitudinal cross-sectional view of the vehicle body structure according to the third embodiment; a perspective view of a second reinforcing member according to the third embodiment; a longitudinal cross-sectional view of the vehicle body structure according to the third embodiment; a longitudinal cross-sectional view of the vehicle body structure according to the fourth embodiment; a longitudinal cross-sectional view of the vehicle body structure according to the fifth embodiment; a longitudinal cross-sectional view of a vehicle body structure according to a modified example of the fifth embodiment; a longitudinal cross-sectional view of a vehicle body structure according to the sixth embodiment; a longitudinal cross-sectional view of a vehicle body structure according to a modified example of ... the seventh embodiment; a longitudinal cross-sectional view of a vehicle body structure according to a modified example of the seventh embodiment.

[0033] Hereinafter, embodiments will be described with reference to the drawings. Identical or corresponding elements are designated by the same reference numerals throughout the drawings, and detailed descriptions will be omitted. The vehicle length direction corresponds to the front-rear direction (X direction in the drawings), the vehicle width direction corresponds to the left-right direction (Y direction in the drawings), and the vehicle height direction corresponds to the up-down direction (Z direction in the drawings). The outer side in the vehicle width direction is the side farther from the vehicle width centerline, and the inner side in the vehicle width direction is the side closer to the vehicle width centerline.

[0034] 1, a vehicle body structure 1 according to a first embodiment includes a pair of side sills 2 extending in the vehicle length direction. The pair of side sills 2 are disposed at the lower portions of both sides in the vehicle width direction.

[0035] The vehicle body structure 1 further includes a first member and a second member between the pair of side sills 2, i.e., on the inside of each side sill 2 in the vehicle width direction. The first member and the second member are arranged at approximately the same position as the side sill 2 in the vehicle height direction. The second member is aligned below the first member in the vehicle height direction. The first member is joined to the side sill 2. The second member is adjacent to the side sill 2 with a gap in between in the vehicle width direction. However, the second member may also be in contact with or joined to the underside of the side sill 2.

[0036] In this embodiment, the first member is a floor cross member 3 (see FIG. 2 ). An example of the second member is a battery case 4. In this embodiment, in which the battery case 4 is used, the vehicle body structure 1 is applied to an electric vehicle that runs by driving a motor with electric power supplied from a battery 5 housed in the battery case 4.

[0037] The vehicle center of gravity G is located at the center of the vehicle body structure 1. In a side view, the vehicle center of gravity G is positioned in the middle between the front end and the rear end of the vehicle body structure 1. The center of the vehicle length direction of the entire vehicle body structure 1 is also the center of the side sill 2 in the vehicle length direction. A B-pillar 6 extends upward from the center of the side sill 2 in the vehicle length direction. In a side view, the vehicle center of gravity G is located near the B-pillar 6.

[0038] In the following description, a longitudinal section refers to a section (extending in the vehicle width direction and vehicle height direction) perpendicular to the vehicle length direction (the longitudinal direction of the side sill 2). A transverse section refers to a section (extending in the vehicle length direction and vehicle height direction) perpendicular to the vehicle width direction (the width direction of the side sill 2). Figure 2 shows a longitudinal section of the right side sill 2 as seen from behind. The pair of side sills 2 are symmetrical, and therefore, a description of the left side sill will be omitted.

[0039] In this example, the side sill 2 includes a side sill inner 10, a side sill outer 20, a first reinforcing member 30, and a second reinforcing member 40. Although not shown here, the side sill may also include other reinforcing members that locally reinforce the side sill outer or inner.

[0040] The side sill inner 10 and the side sill outer 20 are made of steel plate. The first reinforcing member 30 is composed of an extruded aluminum alloy. The second reinforcing member 40 may be made of steel plate, aluminum alloy plate, or extruded shape. Aluminum alloys include 6000 series alloys, 7000 series alloys, and 5000 series alloys, which are commonly used in automobiles due to their strength and formability. In this embodiment, the second reinforcing member 40 is made of the same type of metal as the first reinforcing member 30, i.e., an extruded aluminum alloy. In this case, the second reinforcing member 40 is easily joined to the first reinforcing member 30 by metallurgical joining such as welding.

[0041] The side sill inner 10 and the side sill outer 20 have a hat-shaped longitudinal cross section. The side sill inner 10 has an inner upper flange 11, an inner lower flange 12, and an inner protruding wall 13. The inner upper flange 11 and the inner lower flange 12 are flat plates extending in the vehicle length direction, with their thickness directions oriented in the vehicle width direction and spaced apart in the vehicle height direction. The inner protruding wall 13 connects the lower end of the inner upper flange 11 to the upper end of the inner lower flange 12. The side sill outer 20 has an outer upper flange 21, an outer lower flange 22, and an outer protruding wall 23. The outer upper flange 21 and the outer lower flange 22 are flat plates extending in the vehicle length direction, with their thickness directions oriented in the vehicle width direction and spaced apart in the vehicle height direction. The outer protruding wall 23 connects the lower end of the outer upper flange 21 to the upper end of the outer lower flange 22.

[0042] The side sill outer 20 is disposed on the outside of the side sill inner 10 in the vehicle width direction. The inner upper flange 11 and the outer upper flange 21 are joined to each other in surface contact in the vehicle width direction. The inner lower flange 12 and the outer lower flange 22 are joined to each other in surface contact in the vehicle width direction. Resistance welding such as spot welding can be suitably applied for joining.

[0043] The inner protruding wall 13 protrudes inward in the vehicle width direction relative to the inner upper flange 11 and the inner lower flange 12. The outer protruding wall 23 protrudes outward in the vehicle width direction relative to the outer upper flange 21 and the outer lower flange 22. The side sill 2 has a side sill internal space (hereinafter simply referred to as internal space 2a) defined by the inner surface of the inner protruding wall 13 of the side sill inner panel 10 and the inner surface of the outer protruding wall 23 of the side sill outer panel 20.

[0044] The inner protruding wall 13 has an upper protruding portion 14, a lower protruding portion 15, and a vertical wall portion 16. The upper protruding portion 14 protrudes inward in the vehicle width direction from the lower end of the inner upper flange 11. The lower protruding portion 15 protrudes inward in the vehicle width direction from the upper end of the inner lower flange 12. The vertical wall portion 16 connects the tips of the upper protruding portion 14 and the lower protruding portion 15 to each other in the vehicle height direction. In this embodiment, just as an example, the upper protruding portion 14 inclines downward as it moves inward in the vehicle width direction. The lower protruding portion 15 is approximately horizontal. The vertical wall portion 16 is approximately vertical overall.

[0045] The outer protruding wall 23 also has an upper protruding portion 24, a lower protruding portion 25, and a vertical wall portion 26. The upper protruding portion 24 protrudes outward in the vehicle width direction from the lower end of the outer upper flange 21. The lower protruding portion 25 protrudes outward in the vehicle width direction from the upper end of the outer lower flange 22. The vertical wall portion 26 connects the tips of the upper protruding portion 24 and the lower protruding portion 25 in the vehicle height direction. In this embodiment, as a mere example, the upper protruding portion 24 inclines downward as it extends outward in the vehicle width direction. The lower protruding portion 25 is approximately horizontal. The vertical wall portion 26 includes a vertical portion 26a extending vertically downward from the tip of the upper protruding portion 24 and an inclined portion 26b inclined outward in the vehicle width direction as it extends upward from the tip of the lower protruding portion 25. The lower end of the vertical portion 26a is continuous with the upper end of the inclined portion 26b. In other words, the vertical wall portion 26 is bent at this continuous portion.

[0046] The floor cross member 3 has a main body portion 3a and a pair of joint portions 3b (only one of which is shown in FIG. 2 ). The main body portion 3a has a closed rectangular or hat-shaped cross section and extends in the vehicle width direction. The pair of joint portions 3b protrude outward in the vehicle width direction from both ends of the upper wall of the main body portion 3a in the vehicle width direction. The pair of joint portions 3b are respectively joined to the pair of side sills 2. In this embodiment, the joint portions 3b are flat, and their thickness direction is oriented along the vehicle height direction. The joint portions 3b are joined to the inner protruding wall 13 of the side sill inner panel 10 in surface contact with the outer surface (upper surface) of the upper protruding portion 14 of the inner protruding wall 13. The floor cross member 3 is made of the same metal as the side sill 2, i.e., steel. Metallurgical joining such as welding can be suitably applied for joining. When welding is applied, point joining such as spot welding or line joining such as lap welding may be applied. The end face of the main body 3a in the vehicle width direction is in contact with or close to the outer surface (the inner side surface in the vehicle width direction) of the vertical wall portion 16 of the corresponding inner protruding wall 13.

[0047] Although the longitudinal cross section shown in Figure 2 shows only one floor cross member 3 extending in the vehicle width direction, multiple floor cross members 3 are arranged at intervals in the vehicle length direction. A plate-shaped floor panel 7 is joined in a horizontal position to the underside of the main body portion 3a of the floor cross member 3. A passenger compartment 8 is formed above the floor panel 7. A space for arranging a battery case 4 is secured below the floor panel 7 and between the pair of side sills 2. In this manner, in this embodiment, the battery case 4, which serves as the second member, is arranged below the floor cross member 3, which serves as the first member.

[0048] The case body of the battery case 4 is composed of an outer peripheral frame 4a that has a rectangular window frame shape in plan view, a bottom plate 4b that covers the lower side of the outer peripheral frame 4a, and an upper cover 4c that covers the upper side of the outer peripheral frame 4a. The battery case 4 forms a battery storage space 4d that is defined by the inner surfaces of the case body (the inner peripheral surface of the outer peripheral frame 4a, the inner surface (upper surface) of the bottom plate 4b, and the inner surface (lower surface) of the upper cover 4c). The battery 5 is stored in the battery storage space 4d. An undercover may be provided on the lower surface side of the bottom plate 4b.

[0049] The outer peripheral frame 4a is provided with a pair of mounting portions 4e in the vehicle width direction. As a mere example, the pair of mounting portions 4e protrude outward in the vehicle width direction from the lower end of the outer peripheral surface of a pair of side walls of the outer peripheral frame 4a. Each mounting portion 4e is joined to the inner protruding wall 13 with the upper surface of each mounting portion 4e in surface contact with the outer surface (lower surface) of the lower protruding portion 15 of the corresponding side sill inner panel 10.

[0050] As shown in the illustrated example, the outer periphery frame 4a may be formed of an extruded aluminum alloy material. In this case, the mounting portion 4e may be integrally formed with the outer periphery frame 4a in the extruded material and have a closed rectangular cross section. This allows the battery case 4 to be preferably joined to the side sill 2 by mechanical joining. For example, a bolt 81 is inserted into the mounting portion 4e from below, passes through the lower protrusion 15 of the side sill inner panel 10, and is threaded into a nut 82 installed on the inner surface (upper surface) of the lower protrusion 15.

[0051] The battery case 4 is joined to the underside of the side sill 2. The outer peripheral surface of the outer peripheral frame 4a is adjacent to, and spaced apart from, the outer surface (the inner side surface in the vehicle width direction) of the vertical wall portion 16 of the side sill inner panel 10 in the vehicle width direction.

[0052] The first reinforcing member 30 and the second reinforcing member 40 are disposed in the interior space 2a. The first reinforcing member 30 is disposed so as to be aligned in the vehicle width direction with the floor cross member 3 as the first member. The second reinforcing member 40 is disposed so as to be aligned in the vehicle width direction with the battery case 4 as the second member. Because the floor cross member 3 is disposed above the battery case 4, the first reinforcing member 30 is disposed above the second reinforcing member 40.

[0053] The first reinforcing member 30 is formed of an extruded member having a plurality of closed cross sections 30a arranged in the vehicle width direction and extending in the vehicle length direction. In this embodiment, the plurality of closed cross sections 30a are arranged in a single row and are not stacked in the vehicle height direction. The shape of the closed cross sections 30a is not limited to the rectangular shape shown in the illustration and can be modified as appropriate.

[0054] The first reinforcement member 30 has an upper wall 31, a lower wall 32, an outer wall 33, an inner wall 34, and one or more (e.g., two) partition walls 35, which extend in the vehicle length direction. The upper wall 31 and the lower wall 32 are spaced apart in the vehicle height direction and extend horizontally in the vehicle width direction. The outer wall 33 connects outer ends of the upper wall 31 and the lower wall 32 in the vehicle height direction, and the inner wall 34 connects inner ends of the upper wall 31 and the lower wall 32 in the vehicle height direction. The partition wall 35 extends between the outer wall 33 and the inner wall 34 in the vehicle width direction, parallel to the outer wall 33 and the inner wall 34, and connects the inner surfaces of the upper wall 31 and the lower wall 32 in the vehicle height direction. As a result, multiple (the number of partition walls 35 is one more) closed cross sections 30a form a rectangle and are aligned in the vehicle width direction.

[0055] The outer wall 33 of the first reinforcement member 30 is adjacent to or in surface contact with the inner surface (the inner side surface in the vehicle width direction) of the vertical wall portion 26, particularly the vertical portion 26a, of the side sill outer panel 20. The inner wall 34 of the first reinforcement member 30 is adjacent to or in surface contact with the inner surface (the outer side surface in the vehicle width direction) of the vertical wall portion 16 of the side sill inner panel 10.

[0056] The first reinforcing member 30 is joined to at least one of the side sill inner member 10 and the side sill outer member 20 via a bracket 50. In this embodiment, the bracket 50 is welded to the outer protruding wall 23 of the side sill outer member 20. The bracket 50 is made of a steel plate, that is, it is made of the same type of metal as the side sill 2 but a different type of metal from the first reinforcing member 30.

[0057] 2 and 4 , the bracket 50 has a pair of flanges 51, a pair of upright portions 52, and a support portion 53. The pair of flanges 51 are spaced apart in the vehicle length direction. Each flange 51 is a plate extending in the vehicle width direction, with its thickness oriented along the vehicle height direction. The flanges 51 are joined to the outer protruding wall 23 in surface contact with the inner surfaces of the lower protruding portion 25 and the inclined portion 26b. Spot welding is preferably used for this joining. The pair of upright portions 52 extend upward from each of the pair of flanges 51. The support portion 53 connects the upper edges of the pair of upright portions 52 to each other in the vehicle length direction. The support portion 53 extends horizontally in the vehicle width direction and vehicle length direction, with its thickness oriented in the vehicle height direction. The lower surface of the first reinforcing member 30 is supported by the upper surface of the support portion 53. The first reinforcing member 30 is fastened to the bracket 50 via a rivet 83 inserted into the support portion 53 from below. As a result, the first reinforcing member 30 is mechanically joined to the side sill 2, which is made of a different metal, via the bracket 50. The two brackets 50 are disposed at the front and rear ends of the interior space 2a, respectively, and are spaced apart from each other in the vehicle length direction. Both ends of the first reinforcing member 30 are supported by these two brackets 50.

[0058] 3 and 4, the second reinforcing member 40 has a hat-shaped cross section (a cross section perpendicular to the vehicle width direction). The second reinforcing member 40 is disposed in the internal space 2a with the hat-shaped cross section facing upward.

[0059] The second reinforcing member 40 has a bottom wall portion 41, a pair of upright portions 42, and a pair of flanges 43. The bottom wall portion 41 extends in the vehicle length direction and the vehicle width direction in a plan view, and its plate thickness direction is oriented in the vehicle height direction. The pair of upright portions 42 rise from each of the two edge portions of the bottom wall portion 41 in the vehicle length direction, and their plate thickness direction is oriented along the vehicle length direction. In this embodiment, the upright portions 42 serve as plate-like portions 40a extending in the vehicle height direction and the vehicle width direction in the internal space 2a. The pair of flanges 43 are bent from the respective upper edge portions of the pair of upright portions 42 toward opposite sides in the vehicle length direction. Each flange 43 extends in the vehicle width direction and the vehicle length direction, and its plate thickness direction is oriented in the vehicle height direction.

[0060] The pair of flanges 43 are in surface contact with the outer surface (lower surface) of the lower wall 32 of the first reinforcing member 30 and are joined to the first reinforcing member 30. The second reinforcing member 40 is made of the same type of metal as the first reinforcing member 30, i.e., an aluminum alloy. Metallurgical joining such as welding can be suitably used to join the second reinforcing member 40 to the first reinforcing member 30. The pair of upright portions 42 extend from each of the pair of flanges 43 toward sides away from the first reinforcing member 30 in the vehicle height direction. The bottom wall portion 41 connects the pair of upright portions 42 to each other.

[0061] One end of the second reinforcing member 40 in the vehicle width direction is adjacent to or abuts against the inner surface (the inner side surface in the vehicle width direction) of the vertical wall portion 26 of the side sill outer 20, particularly the inclined portion 26b. The other end of the second reinforcing member 40 in the vehicle width direction is adjacent to or abuts against the inner surface (the outer side surface in the vehicle width direction) of the vertical wall portion 16 of the side sill inner 10. The second reinforcing member 40 is spaced upward from both the lower protruding portion 25 of the side sill outer 20 and the lower protruding portion 15 of the side sill inner 10.

[0062] 4, in this embodiment, by way of example only, four second reinforcing members 40 (40A to 40D) are provided on the side sill 2. The four second reinforcing members 40 are arranged more densely in a central region A1 that includes the vehicle center of gravity G in a side view than in end regions A2, A3 that are further away from the vehicle center of gravity in the vehicle length direction. Two second reinforcing members 40B, 40C are arranged in the central region A1. In contrast, only one second reinforcing member 40A arranged at the front end is arranged in the front end region A2. Only one second reinforcing member 40D arranged at the rear end is arranged in the rear end region A3.

[0063] In other words, the four second reinforcing members 40 (40A to 40D) are arranged at unequal intervals in the vehicle length direction. The two second reinforcing members 40B, 40C in the center in the vehicle length direction are spaced apart by a first distance D1. The two front second reinforcing members 40A, 40B are spaced apart by a second distance D2, and the two rear second reinforcing members 40C, 40D are also spaced apart by a second distance D2. The second distance D2 is larger than the first distance D1.

[0064] When assembling the side sill 2 configured as described above, first, the multiple second reinforcing members 40 are joined to the first reinforcing member 30 by welding. Furthermore, two brackets 50 are joined to the first reinforcing member 30 with rivets 83. The first reinforcing member 30 with the second reinforcing members 40 and brackets 50 attached thereto is partially housed in the side sill outer 20 and joined to the side sill outer 20. This joining is achieved by welding the brackets 50 to the side sill outer 20. The side sill outer 20 with the first reinforcing members 30 and second reinforcing members 40 attached thereto is joined by welding to the side sill inner 10 to which the floor cross member 3 has been previously joined. After the side sill 2 is assembled in this manner, the battery case 4 is joined to the side sill 2.

[0065] Because the first reinforcing member 30 and the second reinforcing member 40 are formed from the same type of metal, they can be easily joined by metallurgical joining such as welding. The first reinforcing member 30 and the second reinforcing member 40 can be made into a sub-assembly before being attached to the side sill outer panel 20. Therefore, the side sill 2 can be easily manufactured.

[0066] According to the vehicle body structure 1 configured as described above, in the event of a side collision, the first reinforcing members 30 are crushed sequentially from the outer side in the vehicle width direction, absorbing the impact energy. As the first reinforcing members 30 are crushed, they transmit the load to the floor cross member 3. This improves the energy absorption performance of the vehicle body structure 1 as a whole.

[0067] The outer wall 33 of the first reinforcement member 30 is parallel to the vertical portion 26a of the side sill outer 20 and is close to or abuts against the inner surface of the vertical portion 26a. The inner wall 34 of the first reinforcement member 30 is parallel to the vertical wall portion 16 of the side sill inner 10 and is close to or abuts against the inner surface of the vertical wall portion 16. Therefore, during a side collision, the side sill outer 20 can effectively transmit the load to the first reinforcement member 30, and the first reinforcement member 30 can effectively transmit the load to the side sill inner 10. Therefore, the load is easily transmitted to the floor cross member 3, improving the energy absorption performance of the vehicle body structure 1 as a whole.

[0068] The first reinforcing member 30 extends in the vehicle length direction within the interior space 2a. The first reinforcing member 30 is long and is housed in the interior space 2a from the front end to the rear end. Therefore, regardless of the position in the vehicle length direction at which a load is input to the side sill 2 during a side collision, the first reinforcing member 30 and the floor cross member 3 can stably absorb the impact energy.

[0069] The second reinforcement member 40 is disposed below the first reinforcement member 30. During a side collision, the side sill 2 as a whole is displaced inward in the vehicle width direction and comes into contact with the battery case 4. The second reinforcement member 40 then transmits the load to the battery case 4 while deforming. This further improves the overall energy absorption performance of the vehicle body structure 1. The second reinforcement member 40 has a plate-shaped portion 40a extending in the vehicle width direction and vehicle height direction in the internal space 2a, and a bottom wall portion 41 extending in the vehicle width direction and vehicle length direction, and this, together with the first reinforcement member 30, forms a closed cross-sectional portion extending in the vehicle width direction. By adopting such a structure and arrangement, the ratio of deformation load to weight can be increased when a load is input in the vehicle width direction, and the second reinforcement member 40 can efficiently absorb impact energy.

[0070] The second reinforcement members 40 have a hat-shaped cross section and are locally arranged in the vehicle length direction. By adopting this configuration, the ratio of deformation load to weight is further increased, and high energy absorption performance can be achieved even with a reduced number of second reinforcement members 40.

[0071] The first reinforcement member 30 and the second reinforcement member 40 are arranged side by side in the vehicle height direction in the internal space 2a. Compared to when only the first reinforcement member 30, which is formed of an extrusion extending in the vehicle length direction, is used and the height of the first reinforcement member 30 is increased, the weight of the side sill 2 and therefore the vehicle body structure 1 can be reduced. Compared to when only the second reinforcement member 40 is used, the number and size of the second reinforcement members 40 can be reduced, thereby reducing the weight of the side sill 2 and therefore the vehicle body structure 1. The positions of the first reinforcement member 30 and the second reinforcement member 40 are determined in relation to the first member (e.g., floor cross member 3) and the second member (e.g., battery case 4) located inside the side sill inner member 10 in the vehicle width direction. This allows the entire vehicle body structure 1 to absorb loads input from the outside toward the inside in the vehicle width direction. In this way, according to this embodiment, the weight of the vehicle body structure 1 can be reduced while improving the energy absorption performance of the vehicle body structure 1.

[0072] The second reinforcing members 40 are arranged at intervals in the vehicle length direction. The second reinforcing members 40 are arranged locally, which makes it possible to suppress an increase in weight due to the application of the second reinforcing members 40.

[0073] The number of second reinforcement members 40 is at least one, and preferably two to five. If an attempt were made to obtain the same level of energy absorption performance as in this embodiment using only the second reinforcement members 40 without applying the first reinforcement member 30, approximately six to fourteen second reinforcement members 40 would be required. By applying both the first reinforcement member 30 and the second reinforcement member 40 as in this embodiment and determining the positions of the first reinforcement member 30 and the second reinforcement member 40 in relation to the members disposed outside the side sill 2, the number of second reinforcement members 40 can be effectively reduced. This allows for both weight reduction and improved energy absorption performance.

[0074] The second reinforcements 40 are arranged more densely in the central region A1, which includes the vehicle center of gravity G, than in the end regions A2, A3. This effectively enables the second reinforcements 40 to deform in addition to the first reinforcements 30 during a side collision. By considering the density of the arrangement of the second reinforcements 40, it is possible to minimize the number of second reinforcements 40 while maintaining high energy absorption performance of the side sill 2 and, ultimately, the vehicle body structure 1.

[0075] 5 shows a modification of the first embodiment. In this modification, the number of second reinforcing members 40 is three. The three second reinforcing members 40 are arranged at equal intervals in the vehicle length direction, and are concentrated near the vehicle center of gravity G. Therefore, no second reinforcing members 40 are provided at either end of the side sill 2 in the vehicle length direction.

[0076] In this modification, the arrangement density of the second reinforcing members 40 increases as the second reinforcing members 40 are closer to the vehicle center of gravity G. This makes it possible to achieve both a reduction in weight of the vehicle body structure 1 and an improvement in energy absorption performance. In this way, the number and arrangement density of the second reinforcing members 40 can be changed as appropriate.

[0077] Second Embodiment Next, a vehicle body structure 1 according to a second embodiment will be described with reference to FIGS. 6 to 8, focusing on the differences from the first embodiment.

[0078] 6 and 7 , in the vehicle body structure 1 or the side sill 2 thereof according to this embodiment, the second reinforcing member 40 is made of a steel plate and is formed of a different type of metal from the first reinforcing member 30. The second reinforcing member 40 is not joined to the first reinforcing member 30. The second reinforcing member 40 is disposed in the internal space 2a and disposed below the first reinforcing member 30 with a gap therebetween.

[0079] In the first embodiment, the second reinforcing member 40 was a hat-shaped sheet metal material, whereas in the present embodiment, the second reinforcing member 40 is a sheet metal material made up of flat plate-shaped parts that are perpendicular to the vehicle length direction.

[0080] 7 , the second reinforcing member 40 has one plate-shaped portion 40a. The plate-shaped portion 40a extends in the vehicle height direction and the vehicle width direction, and its plate thickness direction is oriented in the vehicle length direction. The plate-shaped portion 40a is provided with a stiffening bead 44 for stiffening purposes. The stiffening bead 44 is, for example, X-shaped, but the shape of the stiffening bead 44 is not particularly limited.

[0081] The second reinforcing member 40 further has a lower flange 45, an outer flange 46, and an inner flange 47. The lower flange 45 is bent in the vehicle length direction from the lower edge of the plate-shaped portion 40a, extends in the vehicle width direction, and its plate thickness direction is oriented in the vehicle height direction. The outer flange 46 is bent in the vehicle length direction from the outer edge of the plate-shaped portion 40a in the vehicle width direction. The outer flange 46 extends at an incline so as to be outward in the vehicle width direction as it extends upward, and its plate thickness direction is oriented in a direction perpendicular to the extending direction. The inner flange 47 is bent in the vehicle length direction from the inner edge of the plate-shaped portion 40a in the vehicle width direction. The inner flange 47 extends in the vehicle height direction, and its plate thickness direction is oriented in the vehicle width direction.

[0082] 6 and 8 , the lower flange 45 is placed on the inner surface (upper surface) of the lower protruding portion 15 of the side sill inner panel 10 and joined to the inner protruding wall 13. The outer flange 46 is in surface contact with or positioned close to the inner surface (inner side surface in the vehicle width direction) of the inclined portion 26b of the side sill outer panel 20 via an adhesive. The inner flange 47 is joined to the inner protruding wall 13 while in surface contact with the inner surface (outer side surface in the vehicle width direction) of the vertical wall portion 16 of the side sill inner panel 10. The second reinforcing member 40 is formed from the same type of metal as the side sill inner panel 10 and the side sill outer panel 20. Spot welding can be suitably applied to join each flange of the second reinforcing member 40 to the side sill inner panel 10 or the side sill outer panel 20. The second reinforcing member 40 may be joined to the side sill inner panel 10 first, and then joined to the side sill outer panel 20 together with the side sill inner panel 10. Conversely, the second reinforcing member 40 may be joined to the side sill outer member 20 first, and then joined to the side sill inner member 10 together with the side sill outer member 20 .

[0083] Referring to Figure 8, five second reinforcements 40 are provided. The three central second reinforcements 40 are arranged relatively closely together. The front end second reinforcements 40 are arranged on the front side at a wider interval than the intervals between the three central second reinforcements 40. The rear end second reinforcements 40 are similarly arranged on the rear side at a wider interval. As a result, in this embodiment as well, the arrangement density of the second reinforcements 40 increases the closer they are to the vehicle center of gravity G. This makes it possible to achieve both weight reduction of the vehicle body structure 1 and improved energy absorption performance.

[0084] When assembling the side sill 2 configured as described above, first, the multiple second reinforcing members 40 are joined to the side sill inner 10. Meanwhile, two brackets 50 are joined to the first reinforcing member 30 with rivets 83, and the first reinforcing member 30 with the brackets 50 is joined to the side sill outer 20. Next, the side sill inner 10 with the second reinforcing members 40 is joined to the vehicle body, and then joined to the side sill outer 20 with the first reinforcing members 30. At this time, the second reinforcing members 40 are joined to the side sill outer 20 via an adhesive or are arranged so as to be adjacent to the side sill outer 20 with a small gap between them.

[0085] Before assembling the side sill inner 10 and the side sill outer 20, the first reinforcing member 30 can be joined to the side sill outer 20 to form a sub-assembly, and the second reinforcing member 40 can be joined to the side sill inner 10 to form a sub-assembly. Therefore, the side sill 2 can be easily manufactured.

[0086] Third Embodiment Next, a vehicle body structure 1 according to a third embodiment will be described with reference to FIGS. 9 to 11, focusing on differences from the above-described embodiments.

[0087] The vehicle body structure 1 or its side sill 2 according to this embodiment is similar to the first embodiment and its modified examples in that the second reinforcing members 40 are hat-shaped. The number and arrangement density of the second reinforcing members 40 are similar to the modified examples of the first embodiment. The second reinforcing members 40 are similar to the second embodiment in that they are made of steel plate and are arranged below the first reinforcing members 30 at a distance from the first reinforcing members 30.

[0088] 9 and 10, the second reinforcing member 40 has a top plate portion 41A, a pair of hanging portions 42A, and flange portions (a pair of flanges 43, a pair of inner flanges 47, and an upper flange 48).

[0089] The top plate portion 41A is disposed below and spaced from the underside of the first reinforcing member 30, extends in the vehicle length direction and the vehicle width direction in a plan view, and has its plate thickness direction oriented in the vehicle height direction. The pair of hanging portions 42A extend downward from both edges of the top plate portion 41A in the vehicle length direction, and have their plate thickness direction oriented in the vehicle length direction. In this embodiment, the hanging portions 42A serve as plate-like portions 40a extending in the vehicle height direction and the vehicle width direction in the internal space 2a.

[0090] The flange portions are formed by bending the top plate portion 41A and the hanging portion 42A, and are joined to the side sill inner panel 10 or the side sill outer panel 20. The pair of flanges 43 are bent from the lower edges of the pair of hanging portions 42A in opposite directions in the vehicle length direction. Each flange 43 extends in the vehicle width direction and the vehicle length direction, with its thickness direction oriented in the vehicle height direction. The pair of inner flanges 47 are bent from the inner edges of the pair of hanging portions 42A in the vehicle width direction in opposite directions in the vehicle length direction. The thickness direction of each inner flange 47 is oriented in the vehicle width direction. The upper flange 48 is bent upward from the inner edge of the top plate portion 41A in the vehicle width direction, with its thickness direction oriented in the vehicle width direction.

[0091] 9 and 11 , the pair of flanges 43 are placed on the inner surface (upper surface) of the lower protruding portion 15 of the side sill inner panel 10 and the inner surface (upper surface) of the lower protruding portion 25 of the side sill outer panel 20, and are joined to both the inner protruding wall 13 and the outer protruding wall 23. The pair of inner flanges 47 and upper flanges 48 are joined to the inner protruding wall 13 while being in surface contact with the inner surface (the outer side surface in the vehicle width direction) of the vertical wall portion 16 of the side sill inner panel 10. The second reinforcing member 40 is formed from the same type of metal as the side sill inner panel 10 and the side sill outer panel 20. Spot welding can be suitably used to join each flange of the second reinforcing member 40 to the side sill inner panel 10 or the side sill outer panel 20.

[0092] In this embodiment, similarly to the above-described embodiment, it is possible to achieve both a reduction in the weight of the vehicle body structure 1 and an improvement in the energy absorption performance.

[0093] (Fourth embodiment) Figure 12 shows a vertical cross section of a vehicle body structure 1 according to a fourth embodiment. The vehicle body structure 1 according to this embodiment includes a ladder frame 9 instead of the battery case 4. The ladder frame 9 has a pair of side frames 9a in the vehicle width direction (only one side is shown in Figure 12). Each side frame 9a extends in the vehicle length direction below the floor panel 7. The side frames 9a are disposed inward of the side sills 2 in the vehicle width direction and are adjacent to the side sills 2 with a gap in the vehicle width direction. In this embodiment, the ladder frame 9, and in particular its side frames 9a, serve as the second member of the vehicle body structure 1. The other configurations are the same as those of the first embodiment. The second reinforcing member 40 is disposed so as to be aligned with the side frames 9a of the ladder frame 9 in the vehicle width direction.

[0094] During a side collision, the side sill 2 as a whole is displaced inward in the vehicle width direction and comes into contact with the ladder frame 9. The second reinforcing member 40 then deforms and transmits the load to the ladder frame 9. Therefore, in this embodiment as well, the energy absorption performance of the vehicle body structure 1 as a whole is high.

[0095] 13A shows a longitudinal cross section of a vehicle body structure 1 according to a fifth embodiment. In this embodiment, the vertical wall portion 26 of the side sill outer panel 20 extends vertically between the tip of the upper protrusion 24 and the tip of the lower protrusion 25, and the inclined portion 26b (see FIG. 2) in the above embodiment is omitted. In this way, the outer shape of the side sill 2 can be changed as needed.

[0096] The vehicle body structure 1 includes a floor cross member 3 as a first member and a ladder frame 9 as a second member. The first reinforcing member 30 is formed of an aluminum alloy extrusion, as in the above embodiment. The second reinforcing member 40 is a hat-shaped member made of an aluminum alloy plate, as in the first embodiment.

[0097] In this embodiment, the first reinforcing member 30 is arranged to be aligned with the second member (ladder frame 9) in the vehicle width direction. The second reinforcing member 40 is arranged to be aligned with the first member (floor cross member 3) in the vehicle width direction.

[0098] The second reinforcing member 40 is joined to the upper surface of the first reinforcing member 30 in an upside-down position compared to the first embodiment. The second reinforcing member 40 is formed from the same type of metal as the first reinforcing member 30, i.e., an aluminum alloy. Therefore, metallurgical joining such as welding can be suitably applied for this joining. A pair of flanges 43 of the second reinforcing member 40 is joined to the first reinforcing member 30 while being placed on the upper surface of the first reinforcing member 30. A pair of upstanding portions 42 of the second reinforcing member 40 extend upward relative to the first reinforcing member 30 and the pair of flanges 43. The bottom wall portion is positioned above the pair of flanges 43 and connects the pair of upstanding portions 42 to each other in the vehicle length direction.

[0099] In this embodiment, during a side collision, the second reinforcement member 40 transmits the load to the floor cross member 3 as the first member, and the first reinforcement member 30 transmits the load to the ladder frame 9 as the second member. Therefore, similar to the above embodiment, the overall energy absorption performance of the vehicle body structure 1 is improved. Furthermore, by limiting the number of second reinforcement members 40 and providing a gradient in the arrangement density of the second reinforcement members 40 in the vehicle length direction as in the above embodiment, the weight of the vehicle body structure 1 can also be reduced.

[0100] 13B shows a modification of the fifth embodiment. In this modification, the second reinforcing member 40 is changed from a hat-shaped sheet metal material or an extruded member to a steel sheet metal material similar to that of the second embodiment. In this example, similar to the above embodiment, it is possible to achieve both a reduction in the weight of the vehicle body structure 1 and an improvement in energy absorption performance.

[0101] 14A shows a longitudinal cross section of a vehicle body structure 1 according to a sixth embodiment. In this embodiment, the first reinforcing member 30 has a protruding portion 36. The protruding portion 36 protrudes downward from the outer end portion in the vehicle width direction. This downward portion is the side on which the second reinforcing member 40 is disposed as viewed from the first reinforcing member 30, out of both sides in the vehicle height direction.

[0102] The first reinforcing member 30 is arranged to be aligned with the floor cross member 3 as a first member in the vehicle width direction. The second reinforcing member 40 is joined to the underside of the first reinforcing member 30 and arranged to be aligned with the ladder frame 9 as a second member in the vehicle width direction. The protruding portion 36 covers the second reinforcing member 40 from the inside in the vehicle width direction in the internal space 2a. The protruding portion 36 is plate-shaped, and its plate thickness direction is oriented in the vehicle width direction. The protruding portion 36 is sandwiched between the vertical wall portion 16 of the side sill inner 10 and the inside end face of the second reinforcing member 40 in the vehicle width direction.

[0103] During a side collision, the first reinforcement 30 transmits the load to the floor cross member 3. The second reinforcement 40 transmits the load to the ladder frame 9 after the side sill 2 is displaced inward in the vehicle width direction and comes into contact with the ladder frame 9. The presence of the protrusion 36 increases the unity between the first reinforcement 30 and the second reinforcement 40 when a load in the vehicle width direction is input to the side sill 2, preventing a large shear load from being input between the first reinforcement 30 and the second reinforcement 40. Therefore, breakage of the first reinforcement 30 and the second reinforcement 40 can be suppressed.

[0104] 14B shows a modified example of the sixth embodiment. In this modified example, a protruding portion 36 protrudes downward from the inner end portion of the first reinforcing member 30 in the vehicle width direction. The protruding portion 36 covers the second reinforcing member 40 from the outside in the vehicle width direction. The protruding portion 36 is plate-shaped and is sandwiched between the vertical wall portion 26 of the side sill outer panel 20 and the outer end face of the second reinforcing member 40 in the vehicle width direction. In this example, as in the above embodiment, breakage of the first reinforcing member 30 and the second reinforcing member 40 can be suppressed.

[0105] (Seventh embodiment) Figure 15A shows a longitudinal cross section of a vehicle body structure 1 according to a seventh embodiment. In this embodiment, the first reinforcing member 30 also has a protruding portion 36. Whereas in the sixth embodiment the protruding portion 36 was a plate-like portion formed integrally with the extruded material, in this embodiment the protruding portion 36 forms a closed cross section. The protruding portion 36 protrudes downward from the outer end portion of the first reinforcing member 30 in the vehicle width direction. The second reinforcing member 40 is connected to the underside of the first reinforcing member 30. The protruding portion 36 covers the second reinforcing member 40 from the inside in the vehicle width direction. Because the protruding portion 36 has a certain dimension in the vehicle width direction, the dimension of the second reinforcing member 40 in the vehicle width direction is reduced accordingly.

[0106] In this embodiment as well, the presence of the protruding portion 36 can prevent breakage between the first reinforcing member 30 and the second reinforcing member 40. Because the protruding portion 36 forms a closed cross section, the protruding portion 36 can be easily formed during extrusion molding. The first reinforcing member 30 made of an extruded material and having the protruding portion 36 can be easily manufactured.

[0107] 15B shows a modified example of the seventh embodiment. In this modified example, a protruding portion 36 protrudes downward from the inner end portion of the first reinforcing member 30 in the vehicle width direction and covers the second reinforcing member 40 from the outside in the vehicle width direction. The protruding portion 36 forms a closed cross section and is sandwiched between the vertical wall portion 26 of the side sill outer panel 20 and the outer end face of the second reinforcing member 40 in the vehicle width direction. In this example, as in the above embodiment, breakage of the first reinforcing member 30 and the second reinforcing member 40 can be suppressed.

[0108] Although the embodiments have been described above, the above configurations can be appropriately changed, added to, or deleted within the scope of the present disclosure.

[0109] The present disclosure may include the following aspects: (Aspect 1) A vehicle body structure comprising: a side sill extending in a vehicle length direction; a floor cross member as a first member joined to the side sill and arranged inward of the side sill in a vehicle width direction; a second member aligned with the first member in a vehicle height direction, adjacent to the side sill with a gap therebetween, and arranged inward of the side sill in the vehicle width direction, wherein the second member is a battery case that houses a battery or a ladder frame, and the side sill comprises: a side sill inner joined to the first member and adjacent to the second member; a side sill outer arranged outward of the side sill inner in the vehicle width direction; a side sill internal space defined by the side sill inner and the side sill outer; and a first reinforcing member arranged in the side sill internal space so as to be aligned with one of the first member and the second member in the vehicle width direction, the first reinforcing member being formed of an extruded member extending in the vehicle length direction and having a plurality of closed cross sections arranged in the vehicle width direction. A vehicle body structure comprising: one or more second reinforcing members arranged in the side sill internal space so as to be aligned with the other of the first member and the second member in the vehicle width direction, and having a plate-shaped portion extending in the vehicle width direction. (Aspect 2) The vehicle body structure according to Aspect 1, comprising a plurality of the second reinforcing members arranged at intervals from one another in the vehicle length direction. (Aspect 3) The vehicle body structure according to Aspect 2, wherein the plurality of second reinforcing members are arranged more densely in a central region including the vehicle center of gravity in a side view than in end regions away from the vehicle center of gravity in the vehicle length direction. (Aspect 4) The vehicle body structure according to any of Aspects 1 to 3, wherein the first reinforcing member is joined to at least one of the side sill outer or the side sill inner via a bracket. (Aspect 5) The vehicle body structure according to any one of Aspects 1 to 4, wherein the first reinforcing material is arranged to be aligned with the first member in the vehicle width direction, the second reinforcing material is arranged to be aligned with the second member in the vehicle width direction, and the first reinforcing material is arranged above the second reinforcing material.(Aspect 6) The vehicle body structure according to any one of Aspects 1 to 5, wherein the first reinforcing member is constituted by the extrusion member made of an aluminum alloy, the second reinforcing member is made of the aluminum alloy, and the second reinforcing member is joined to an upper surface or a lower surface of the first reinforcing member. (Aspect 7) The vehicle body structure according to Aspect 6, wherein the first reinforcing member has a protruding portion that protrudes from one end or the other end in the vehicle width direction toward the side in the vehicle height direction on which the second reinforcing member is located. (Aspect 8) The vehicle body structure according to Aspect 6 or 7, wherein the second reinforcing member has a pair of flange portions joined to an upper surface or a lower surface of the first reinforcing member, a pair of upright portions as the plate-shaped portion extending from each of the pair of flange portions toward a side away from the first reinforcing member in the vehicle height direction, and a bottom wall portion connecting the pair of upright portions. (Aspect 9) The vehicle body structure according to any one of claims 1 to 5, wherein the second reinforcing member is made of a steel plate, and wherein the second reinforcing member is arranged above or below the first reinforcing member at a distance from the first reinforcing member. (Aspect 10) The vehicle body structure according to claim 9, wherein the second reinforcing member is configured by a sheet metal material having one of the plate-shaped portions extending in the vehicle height direction and the vehicle width direction and a stiffening bead provided on the plate-shaped portion. (Aspect 11) The vehicle body structure according to claim 9, wherein the second reinforcing member has: a top plate portion arranged below a lower surface of the first reinforcing member at a distance, a pair of hanging portions as the plate-shaped portion extending downward from the top plate portion, and a flange portion formed by bending the top plate portion and the pair of hanging portions and joined to the side sill inner or the side sill outer.

[0110] This application claims priority from Japanese Patent Application No. 2023-139216, filed on August 29, 2023, which is incorporated herein by reference.

[0111] REFERENCE SIGNS LIST 1 Vehicle body structure 2 Side sill 2a Interior space 3 Floor cross member 3a Main body portion 3b Joint portion 4 Battery case 4a Peripheral frame 4b Bottom plate 4c Upper cover 4d Battery storage space 4e Mounting portion 5 Battery 6 B-pillar 7 Floor panel 8 Vehicle compartment 9 Ladder frame 9a Side frame 10 Side sill inner 11 Inner upper flange 12 Inner lower flange 13 Inner protruding wall 14 Upper protruding portion 15 Lower protruding portion 16 Vertical wall portion 20 Side sill outer 21 Outer upper flange 22 Outer lower flange 23 Outer protruding wall 24 Upper protruding portion 25 Lower protruding portion 26 Vertical wall portion 26a Vertical portion 26b Inclined portion 30 First reinforcing member 30a Closed cross section 31 Upper wall 32 Lower wall 33 Outer wall 34 Inner wall 35 Partition wall 36 Protruding portion 40, 40A to 40D Second reinforcing member 40a Plate-shaped portion 41 Bottom wall portion 41A Top plate portion 42 Upright portion 42A Hanging portion 43 Flange 44 Stiffening bead 45 Lower flange 46 Outer flange 47 Inner flange 48 Upper flange 50 Bracket 51 Flange 52 Upright portion 53 Support portion 81 Bolt 82 Nut 83 Rivet A1 Central region A2, A3 End regions D1 First distance D2 Second distance G Vehicle center of gravity

Claims

1. A vehicle body structure comprising: a side sill extending in a vehicle length direction; a floor cross member as a first member joined to the side sill and disposed inward of the side sill in a vehicle width direction; and a second member aligned with the first member in a vehicle height direction, adjacent to the side sill with a gap therebetween, and disposed inward of the side sill in the vehicle width direction, wherein the second member is a battery case that houses a battery, or a ladder frame, wherein the side sill comprises: a side sill inner joined to the first member and adjacent to the second member; a side sill outer disposed outward of the side sill inner in the vehicle width direction; a side sill internal space defined by the side sill inner and the side sill outer; and a first reinforcing member disposed in the side sill internal space so as to be aligned with one of the first member and the second member in the vehicle width direction, the first reinforcing member being formed of an extruded member having a plurality of closed cross sections that are aligned in the vehicle width direction, the first reinforcing member extending in the vehicle length direction, and the second reinforcing member being formed of an extruded member having a plurality of closed cross sections that are aligned in the vehicle width direction. one or more second reinforcing members arranged in the side sill internal space so as to be aligned with the other of the first member and the second member in the vehicle width direction, and having a plate-shaped portion extending in the vehicle width direction.

2. The vehicle body structure according to claim 1, comprising a plurality of said second reinforcing members, said plurality of second reinforcing members being arranged at intervals from one another in the vehicle length direction.

3. The vehicle body structure according to claim 2, wherein the plurality of second reinforcing members are arranged more densely in a central region including the vehicle center of gravity in a side view than in end regions remote from the vehicle center of gravity in the vehicle length direction.

4. The vehicle body structure according to claim 1, wherein the first reinforcing member is joined to at least one of the side sill outer and the side sill inner via a bracket.

5. A vehicle body structure as described in any one of claims 1 to 4, wherein the first reinforcement material is arranged so as to be aligned with the first member in the vehicle width direction, the second reinforcement material is arranged so as to be aligned with the second member in the vehicle width direction, and the first reinforcement material is arranged above the second reinforcement material.

6. A vehicle body structure as claimed in any one of claims 1 to 4, wherein the first reinforcing material is constituted by the extrusion material made of an aluminum alloy, the second reinforcing material is made of the aluminum alloy, and the second reinforcing material is joined to the upper or lower surface of the first reinforcing material.

7. A vehicle body structure as set forth in claim 6, wherein the first reinforcing member has a protruding portion that protrudes from one end or the other end in the vehicle width direction toward the side in the vehicle height direction on which the second reinforcing member is disposed.

8. The vehicle body structure described in claim 6, wherein the second reinforcing material has a pair of flange portions joined to the upper or lower surface of the first reinforcing material, a pair of upright portions as the plate-like portion extending from each of the pair of flange portions away from the first reinforcing material in the vehicle height direction, and a bottom wall portion connecting the pair of upright portions to each other.

9. A vehicle body structure as claimed in any one of claims 1 to 4, wherein the second reinforcing member is made of a steel plate, and the second reinforcing member is disposed above or below the first reinforcing member and spaced apart from the first reinforcing member.

10. A vehicle body structure as described in claim 9, wherein the second reinforcing member is constituted by a sheet metal material having one plate-like portion extending in the vehicle height direction and the vehicle width direction, and a stiffening bead provided on the plate-like portion.

11. A vehicle body structure as described in claim 9, wherein the second reinforcing member has a top plate portion spaced downward from the underside of the first reinforcing member, a pair of hanging portions as the plate-like portion extending downward from the top plate portion, and a flange portion formed by bending the top plate portion and the pair of hanging portions and joined to the side sill inner or the side sill outer.

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