Vehicle underbody structure

Abstract

To improve energy absorption during side impacts. [Solution] The lower body structure of the vehicle comprises a floor panel 4, side sills 10 connected to both ends of the floor panel 4 in the vehicle width direction and extending in the vehicle longitudinal direction, reinforcement 15 disposed inside the side sills 10 and extending in the vehicle longitudinal direction, and a cross member 30 disposed on the upper surface of the floor panel 4 and extending in the vehicle width direction. The cross member 30 is positioned to overlap with the reinforcement 15 in a vehicle side view, and the upper surface of the outer end of the cross member 30 in the vehicle width direction is formed to slope upward from the inside in the vehicle width direction to the outside in the vehicle width direction.

Description

Technical Field

[0001] The present disclosure relates to a lower body structure of a vehicle.

Background Art

[0002] In a vehicle such as an electric vehicle including a motor as a drive source for driving the vehicle and a battery for storing electric power supplied to the motor, a large and heavy battery is generally disposed below a floor panel forming a floor surface of a passenger compartment and between a pair of left and right side sills coupled to both end portions in the vehicle width direction of the floor panel.

[0003] For example, in Patent Document 1, in an electric vehicle in which a battery is disposed below a floor panel, a cross member extending in the vehicle width direction is disposed on the upper surface of the floor panel, and reinforcements are disposed inside side sills coupled to both end portions in the vehicle width direction of the floor panel to improve side collision performance. <0>

Prior Art Documents

Patent Documents

[0004] [[ID=]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In vehicles equipped with a reinforcement extending in the longitudinal direction of the vehicle body inside the side sill, positioning the reinforcement so that it overlaps vertically with the cross member located on the upper surface of the floor panel can improve energy absorption by the reinforcement when an impact load acts on the side sill from the outside in the width direction during a side collision. However, there is a risk that the cross member may bend downward due to the load transmitted from the side sill to the cross member, preventing the side sill and reinforcement from adequately absorbing energy.

[0006] The object of this disclosure is to provide a vehicle underbody structure that improves energy absorption during side collisions. [Means for solving the problem]

[0007] This disclosure provides a lower body structure for a vehicle, comprising: a floor panel; side sills connected to both ends of the floor panel in the vehicle width direction and extending in the vehicle longitudinal direction; a reinforcement disposed inside the side sill and extending in the vehicle longitudinal direction; and a cross member disposed on the upper surface of the floor panel and extending in the vehicle width direction, wherein the cross member is positioned to overlap with the reinforcement in a vehicle side view, and the upper surface of the outer end of the cross member in the vehicle width direction is formed to slope upward from the inside in the vehicle width direction to the outside in the vehicle width direction.

[0008] According to this disclosure, a side sill with internally disposed reinforcement is coupled to a floor panel, and a cross member is disposed on the upper surface of the floor panel. The cross member is positioned to overlap with the reinforcement in a vehicle side view, and the upper surface of the outer end in the vehicle width direction is formed to slope upward from the inner side in the vehicle width direction to the outer side. When an impact load acts on the side sill from the outside in the vehicle width direction during a side collision, compared to a case where the upper surface of the outer end of the cross member in the vehicle width direction is formed at the same height as the upper surface of the inner side in the vehicle width direction, the impact load transmitted from the side sill to the cross member through the reinforcement causes the outer end of the cross member in the vehicle width direction to bend downward, suppressing downward bending deformation of the reinforcement, and allowing the side sill and reinforcement to deform straight in the vehicle width direction, thereby improving energy absorption by the side sill and reinforcement.

[0009] The upper end of the cross member and the upper end of the reinforcement may be positioned to overlap when viewed from the side of the vehicle.

[0010] With this configuration, compared to the case where the upper end of the cross member and the upper end of the reinforcement are positioned at different locations when viewed from the side of the vehicle, the side sill and reinforcement can be deformed by collapsing in a straight line in the width direction of the vehicle.

[0011] The lower body structure of the vehicle comprises a battery housing that houses a battery below the floor panel, the battery having a battery module, and the cross member may be formed such that the inner side in the vehicle width direction of the outer end of the cross member in the vehicle width direction overlaps in the vehicle width direction with the outer end of the battery module in the vehicle width direction.

[0012] With this configuration, compared to the case where the outer side of the outer end of the cross member in the vehicle width direction overlaps with the outer end of the battery module in the vehicle width direction in the vehicle width direction, even when the outer side of the outer end of the cross member in the vehicle width direction is crushed and deformed by the impact load transmitted from the side sill to the cross member through the reinforcement during a side collision, interference between the side sill and the battery module can be suppressed, thereby improving the battery's protection performance.

[0013] The cross member comprises an upper surface and side surfaces extending downward from the upper surface, the upper surface is provided with a recess that is recessed downward, and the upper surface of the outer end in the vehicle width direction of the bottom wall of the recess may be formed to slope upward from the inside in the vehicle width direction to the outside in the vehicle width direction.

[0014] With this configuration, compared to a case where no recess is provided on the upper surface of the cross member, and the upper surface of the outer end of the cross member in the vehicle width direction is formed to slope upward from the inside in the vehicle width direction to the outside in the vehicle width direction, the strength and rigidity of the cross member can be improved by the recess provided on the cross member.

[0015] The reinforcement may have a plurality of closed cross-sectional portions arranged in the vehicle width direction.

[0016] With this configuration, compared to using a reinforcement with a single closed section in the vehicle width direction, when an impact load acts on the side sill during a side collision, the impact load causes multiple closed sections to collapse and deform, thereby improving energy absorption by the reinforcement. [Effects of the Invention]

[0017] The lower body structure of the vehicle according to this disclosure can improve energy absorption during a side collision. [Brief explanation of the drawing]

[0018] [Figure 1]It is a plan view of the lower part of the vehicle body to which the lower vehicle body structure according to the embodiment of the present disclosure is applied. [Figure 2] It is a cross-sectional view of the lower part of the vehicle body along the Y2-Y2 line in FIG. 1. [Figure 3] It is a cross-sectional view of the cross member and the floor panel along the Y3-Y3 line in FIG. 2. [Figure 4] It is a view for explaining the deformation of the vehicle body during a side collision.

Mode for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0020] FIG. 1 is a plan view of the lower part of the vehicle body to which the lower vehicle body structure according to the embodiment of the present disclosure is applied. As shown in FIG. 1, the vehicle body 1 to which the lower vehicle body structure according to the embodiment of the present disclosure is applied is a vehicle body such as an electric vehicle including a motor 2 as a drive source for driving the vehicle and a battery 3 for storing electric power supplied to the motor 2 and the like.

[0021] The vehicle body 1 includes, at the lower part of the vehicle body, a flat floor panel 4 forming the floor surface of the passenger compartment, a pair of left and right closed-section side sills 10 respectively connected to both ends in the vehicle width direction of the floor panel 4 and extending in the vehicle longitudinal direction, and a cross member 30 disposed between the pair of left and right side sills 10 on the upper surface of the floor panel 4 and extending in the vehicle width direction.

[0022] FIG. 2 is a cross-sectional view of the lower part of the vehicle body along the Y2-Y2 line in FIG. 1. As shown in FIG. 2, each of the left and right side sills 10 includes a side sill inner 11 constituting the inner side of the vehicle body of the side sill 10 and a side sill outer 12 constituting the outer side of the vehicle body of the side sill 10. The side sill inner 11 and the side sill outer 12 are each formed by pressing a metal plate member such as a steel plate into a substantially hat-shaped cross section.

[0023] The side sill inner 11 comprises an upper surface portion 11a extending substantially horizontally, a lower surface portion 11b located below the upper surface portion 11a and extending substantially horizontally, and a side surface portion 11c extending vertically, with the side surface portion 11c bulging inward into the vehicle body. The side sill inner 11 also comprises an upper flange portion 11d extending upward from the upper surface portion 11a and a lower flange portion 11e extending downward from the lower surface portion 11b.

[0024] The side sill outer 12 comprises an upper surface portion 12a extending substantially horizontally, a lower surface portion 12b located below the upper surface portion 12a and extending substantially horizontally, and a side surface portion 12c extending vertically, with the side surface portion 12c bulging outwards from the vehicle body. The side sill outer 12 also comprises an upper flange portion 12d extending upward from the upper surface portion 12a and a lower flange portion 12e extending downward from the lower surface portion 12b.

[0025] The upper flange portion 11d of the side sill inner 11 and the upper flange portion 12d of the side sill outer 12 are joined together, and the lower flange portion 11e of the side sill inner 11 and the lower flange portion 12e of the side sill outer 12 are joined together. The side sill 10 is formed in a substantially rectangular closed cross-section by the side sill inner 11 and the side sill outer 12, and the closed cross-section portion 13 extends in the longitudinal direction of the vehicle body.

[0026] A reinforcement 15 is provided inside the side sill 10 to reinforce it. The reinforcement 15 extends along the side sill 10 in the longitudinal direction of the vehicle body and is formed in a substantially rectangular closed cross-section. The reinforcement 15 is formed by extruding aluminum.

[0027] The reinforcement 15 has a closed section portion 16 formed in a substantially rectangular closed cross-section. The reinforcement 15 is formed in a closed cross-section with an upper wall portion 15a extending substantially horizontally, a lower wall portion 15b located below the upper wall portion 15a and extending substantially horizontally, an inner wall portion 15c extending substantially vertically by connecting the inner ends of the upper wall portion 15a and the lower wall portion 15b in the vehicle width direction, and an outer wall portion 15d extending substantially vertically by connecting the outer ends of the upper wall portion 15a and the lower wall portion 15b in the vehicle width direction.

[0028] The reinforcement 15 has two partition walls 15e that connect the central sides of the upper wall portion 15a and the lower wall portion 15b in the vehicle width direction and extend substantially vertically, and partition the closed section portion 16. The closed section portion 16 of the reinforcement 15 is partitioned by the two partition walls 15e into three closed section portions 16a, 16b, and 16c that are aligned in the vehicle width direction.

[0029] The three closed sections 16a, 16b, and 16c of the reinforcement 15 are each formed in a substantially rectangular cross-section by an upper wall and a lower wall extending in the vehicle width direction, an inner wall connecting the inner sides of the upper wall and the lower wall in the vehicle width direction, and an outer wall connecting the outer sides of the upper wall and the lower wall in the vehicle width direction. The reinforcement 15 may have one or more closed sections.

[0030] The reinforcement 15 is fixed and supported by the side sill 10, with its inner wall portion 15c attached to the side portion 11c of the side sill inner 11, which constitutes the inner surface of the side sill 10, using bolts B1 and nuts N1 as fastening members. The outer wall portion 15d of the reinforcement 15 is positioned spaced apart from the side portion 12c of the side sill outer 12, which constitutes the outer surface of the side sill 10.

[0031] As shown in Figure 1, two cross members 30 are arranged spaced apart in the longitudinal direction of the vehicle body and joined to the upper surface of the floor panel 4 by welding or the like. The two cross members 30 are similarly configured. As shown in Figure 2, the cross members 30 are positioned to overlap with the reinforcement 15 in a side view of the vehicle. The upper end portion 30a of the cross member 30, specifically the upper surface portion 31 described later, and the upper end portion 15f of the reinforcement 15, specifically the upper wall portion 15a, are positioned to overlap in a side view of the vehicle. The lower end portion 15g of the reinforcement 15, specifically the lower wall portion 15b, is positioned to overlap with the floor panel 4 in the vertical direction.

[0032] Figure 3 is a cross-sectional view of the cross member and floor panel along the Y3-Y3 line in Figure 2. As shown in Figure 3, the cross member 30 is formed by press-forming a metal plate-like member, such as a steel plate, into a roughly hat-shaped cross section. The cross member 30 comprises an upper surface portion 31 extending in a roughly horizontal direction, side portions 32 on both sides extending downward in a roughly vertical direction from the front and rear ends of the upper surface portion 31, and flange portions 33 on both sides extending in a roughly horizontal direction from the side portions 32.

[0033] The cross member 30 has flange portions 33 on both sides joined to the upper surface of the floor panel 4, forming a closed section 34 that extends in the vehicle width direction together with the floor panel 4. As shown in Figure 2, the cross member 30's upper surface portion 31 and side portions 32 on both sides are joined to the upper surface portion 11a and side portions 11c of the side sill inner 11 via brackets 19, and are also joined to the side sill 10.

[0034] As shown in Figure 3, the cross member 30 is provided with a recess 35 that is recessed downward on the front-rear center side of the upper surface portion 31. The recess 35 extends across the entire width of the cross member 30. The recess 35 comprises a bottom wall portion 36 extending in a substantially horizontal direction and side wall portions 37 on both sides that extend substantially vertically upward from the front and rear ends of the bottom wall portion 36, respectively, and is formed in a substantially rectangular cross-section. The bottom wall portion 36 of the recess 35 is positioned at a height approximately equal to the vertical center side of the side portion 32 of the cross member 30. The bottom wall portion 36 may be at a height approximately equal to the upper side of the side portion 32 of the cross member 30, or at a height approximately equal to the lower side of the side portion 32 of the cross member 30.

[0035] As shown in Figure 2, the cross member 30 is formed such that the outer end 36a in the vehicle width direction of the bottom wall portion 36 of the recess 35 inclines upward as it moves from the inner side in the vehicle width direction to the outer side in the vehicle width direction. The inner portion 36b in the vehicle width direction of the bottom wall portion 36 extends horizontally, perpendicular to the vertical direction. The outer end 36a in the vehicle width direction of the bottom wall portion 36 has an inclined portion 36a1 that inclines upward at a predetermined angle as it moves from the inner portion 36b in the vehicle width direction of the bottom wall portion 36 to the outer side in the vehicle width direction, and a horizontal portion 36a2 that extends horizontally outward from the inclined portion 36a1 in the vehicle width direction. The cross member 30 is bent between the inner portion 36b in the vehicle width direction of the bottom wall portion 36 and the inclined portion 36a1 of the outer end 36a in the vehicle width direction, and between the inclined portion 36a1 and the horizontal portion 36a2 of the outer end 36a of the bottom wall portion 36.

[0036] The bottom wall portion 36 of the recess 35 of the cross member 30 is formed by an inclined portion 36a1 on the inner side in the vehicle width direction of the outer end 36a in the vehicle width direction, and by a horizontal portion 36a2 on the outer side in the vehicle width direction of the outer end 36a in the vehicle width direction. The bottom wall portion 36 of the recess 35 may also be formed by only the inclined portion 36a1 without the horizontal portion 36a2 at the outer end 36a in the vehicle width direction.

[0037] In this way, the upper surface of the outer end 38 of the cross member 30 in the vehicle width direction is formed to slope upward from the inner portion 39 of the cross member 30 in the vehicle width direction as it moves from the inner portion to the outer portion. Specifically, the upper surface of the outer end 36a of the bottom wall portion 36 of the recess 35 of the cross member 30 in the vehicle width direction is formed to slope upward from the inner portion 36b in the vehicle width direction as it moves from the inner portion 36b to the outer portion.

[0038] In the vehicle body 1, as shown in Figure 1, the battery 3 is located below the floor panel 4. As shown in Figure 2, the vehicle body 1 includes a battery housing 6 located below the floor panel 4 to house the battery 3, and a battery frame 20 that supports the battery housing 6 and is attached to the left and right side sills 10. The battery 3 has a plurality of battery modules 3a that store power supplied to the motor 2, etc., and the plurality of battery modules 3a are formed as a unit.

[0039] The battery housing 6 has an upper cover 7 that covers the top of the battery 3 and extends substantially horizontally, and a lower cover 8 that covers the bottom of the battery 3 and extends substantially horizontally, with the upper cover 7 being connected to the lower cover 8. The battery 3 is fixed to the battery housing 6. The battery housing 6 is formed, for example, by press-forming aluminum.

[0040] The battery frame 20 is positioned on the outside of the battery housing 6 in the vehicle width direction, extending in the longitudinal direction of the vehicle body, and is formed in a substantially L-shape in cross-section. The battery frame 20 is formed by extruding aluminum. The battery frame 20 extends in the longitudinal direction of the vehicle body and has a closed cross-section portion 21 that is formed in a closed cross-section shape.

[0041] The battery frame 20 is formed in a closed cross-section and has an upper surface portion 22, a lower surface portion 23 located below the upper surface portion 22 and extending substantially horizontally, an inner surface portion 24 connecting the inner ends of the upper surface portion 22 and the lower surface portion 23 in the vehicle width direction and extending vertically, and an outer surface portion 25 connecting the outer ends of the upper surface portion 22 and the lower surface portion 23 in the vehicle width direction and extending vertically.

[0042] The upper portion 22 of the battery frame 20 is positioned lower in the vehicle width direction than the inner portion in the vehicle width direction. The upper portion 25 of the battery frame 20 is positioned inward in the vehicle width direction than the lower portion. The upper and outer corners of the battery frame 20 are recessed due to the outer portion of the upper portion 22 and the upper portion of the outer portion 25, and the battery frame 20 is positioned close to the side sill 10.

[0043] The battery frame 20 is fixedly attached to the upper surface 22 of the upper cover 7 in the vehicle width direction, and to the lower surface 23 of the lower cover 8 in the vehicle width direction, and supports the battery housing 6. The battery frame 20 is fixedly attached to the lower surface of the side sill 10, specifically to the lower surface 11b of the side sill inner 11. In this way, the battery 3 is arranged below the floor panel 4.

[0044] In the vehicle body 1, the cross member 30 is formed such that the inner side 38a of the outer end 38 of the cross member 30 in the vehicle width direction overlaps with the outer end 3b of the battery module 3a in the vehicle width direction, and the inclined portion 36a1 of the outer end 38 of the cross member 30 in the vehicle width direction overlaps with the outer end 3b of the battery module 3a in the vehicle width direction. The inclined portion 36a1 of the outer end 38 of the cross member 30 in the vehicle width direction may be positioned further outward in the vehicle width direction than the outer end 3b of the battery module 3a in the vehicle width direction.

[0045] Figure 4 is a diagram illustrating vehicle body deformation during a side collision. In Figure 4, the solid line shows the results of a simulation analysis of vehicle body deformation when an impact load F acts on the side portion 12c of the side sill outer 12, which constitutes the outer surface portion of the side sill 10, during a side collision. In Figure 4, the dashed line shows the results of a simulation analysis of vehicle body deformation during a side collision for a vehicle body in which the upper surface of the outer end in the vehicle width direction of the bottom wall portion 36 of the recess 35 of the cross member 30 extends horizontally in the same direction as the inner portion in the vehicle width direction.

[0046] As shown by the dashed line in Figure 4, if the upper surface of the outer end in the vehicle width direction of the bottom wall portion 36 of the recess 35 extends horizontally in the same way as the inner portion in the vehicle width direction, then during a side collision, when the outer surface portion 12c of the side sill 10 deforms inward in the vehicle width direction and the reinforcement 15 is crushed and deformed by the load transmitted to the reinforcement 15, the cross member 30 is buckled by the load transmitted from the reinforcement 15 to the cross member 30.

[0047] When the cross member 30 buckles, the outer end of the cross member 30 in the vehicle width direction is bent downward. As a result, the reinforcement 15 is bent downward, and there is a risk that sufficient energy absorption due to the crushing deformation of the side sill 10 and the reinforcement 15 may not be obtained.

[0048] As shown by the solid line in Figure 4, if the upper surface of the outer end in the vehicle width direction of the bottom wall portion 36 of the recess 35 is formed to slope upward from the inner portion in the vehicle width direction toward the outer portion in the vehicle width direction, then in the event of a side collision, the outer surface portion 12c of the side sill 10 is deformed inward in the vehicle width direction, and the reinforcement 15 is crushed and deformed by the load transmitted to the reinforcement 15, and the cross member 30 is buckled by the load transmitted from the reinforcement 15 to the cross member 30.

[0049] In the vehicle body 1, when the cross member 30 buckles, the outer end of the cross member 30 in the vehicle width direction is bent between the inner portion of the cross member 30 in the vehicle width direction and the inclined portion 36a1 on the inner side of the outer end of the cross member 30 in the vehicle width direction, causing the outer side of the inclined portion 36a1 in the vehicle width direction to be lifted and bent. This prevents the outer end of the cross member 30 in the vehicle width direction from bending downward and the reinforcement 15 from bending downward. This allows the side sill 10 and reinforcement 15 to be deformed straight in the vehicle width direction, improving energy absorption by the side sill 10 and reinforcement 15.

[0050] In the vehicle body 1, the description focuses on the outer end in the vehicle width direction on the left side of the cross member 30 located at the rear of the vehicle body, but the outer ends in the vehicle width direction of the other cross members 30 are configured similarly.

[0051] In this embodiment, the upper surface 31 of the cross member 30 is provided with a recess 35 that is recessed downward, and the upper surface of the outer end 36a in the vehicle width direction of the bottom wall 36 of the recess 35 is formed to slope upward as it moves from the inside in the vehicle width direction to the outside in the vehicle width direction. However, the upper surface 31 of the cross member 30 may not be provided with a recess, and the upper surface of the outer end in the vehicle width direction of the upper surface 31 of the cross member 30 may be formed to slope upward as it moves from the inside in the vehicle width direction to the outside in the vehicle width direction.

[0052] As described above, the lower body structure of the vehicle according to this embodiment comprises a floor panel 4, side sills 10 connected to both ends of the floor panel 4 in the vehicle width direction and extending in the vehicle longitudinal direction, reinforcement 15 disposed inside the side sills 10 and extending in the vehicle longitudinal direction, and a cross member 30 disposed on the upper surface of the floor panel 4 and extending in the vehicle width direction. The cross member 30 is positioned to overlap with the reinforcement 15 in a vehicle side view, and the upper surface of the outer end of the cross member 30 in the vehicle width direction is formed to incline upward from the inside in the vehicle width direction to the outside in the vehicle width direction.

[0053] As a result, when an impact load F acts on the side sill 10 from the outside in the vehicle width direction during a side collision, compared to the case where the upper surface of the outer end of the cross member 30 in the vehicle width direction is formed at the same height as the upper surface of the inner end in the vehicle width direction, the impact load transmitted from the side sill 10 to the cross member 30 through the reinforcement 15 suppresses downward bending deformation of the outer end of the cross member 30 in the vehicle width direction and downward bending deformation of the reinforcement 15, thereby causing the side sill 10 and reinforcement 15 to deform straight in the vehicle width direction and improving energy absorption by the side sill 10 and reinforcement 15.

[0054] Furthermore, the upper end 30a of the cross member 30 and the upper end 15f of the reinforcement 15 are positioned to overlap when viewed from the side of the vehicle. This allows the side sill 10 and the reinforcement 15 to deform more straight in the width direction of the vehicle compared to when the upper end 30a of the cross member 30 and the upper end 15f of the reinforcement 15 are positioned at different locations when viewed from the side of the vehicle.

[0055] Furthermore, the lower body structure of the vehicle includes a battery housing 6 that houses the battery 3 below the floor panel 4. The battery 3 has a battery module 3a, and the cross member 30 is formed such that the inner side in the vehicle width direction of the outer end of the cross member 30 in the vehicle width direction overlaps with the outer end of the battery module 3a in the vehicle width direction. This makes it possible to suppress interference between the side sill 10 and the battery module 3a, and improve the protective performance of the battery 3, even when the outer side in the vehicle width direction of the outer end of the cross member 30 in the vehicle width direction is crushed and deformed by the impact load transmitted from the side sill 10 to the cross member 30 through the reinforcement 15 during a side collision.

[0056] Furthermore, the cross member 30 comprises an upper surface portion 31 and side portions 32 on both sides extending downward from the upper surface portion 31. The upper surface portion 31 is provided with a recess 35 that is recessed downward, and the upper surface of the outer end in the vehicle width direction of the bottom wall portion 36 of the recess 35 is formed to slope upward as it moves from the inner side in the vehicle width direction to the outer side in the vehicle width direction. As a result, the strength and rigidity of the cross member 30 can be improved by the recess 35 provided in the cross member 30, compared to a case where the upper surface portion 31 of the cross member 30 is not provided with a recess and the upper surface of the outer end in the vehicle width direction of the cross member 30 is formed to slope upward as it moves from the inner side in the vehicle width direction to the outer side in the vehicle width direction.

[0057] Furthermore, the reinforcement 15 has multiple closed sections 16a, 16b, and 16c arranged in the vehicle width direction. This allows for improved energy absorption by the reinforcement 15 compared to using a reinforcement with a single closed section in the vehicle width direction. When an impact load is applied to the side sill 10 during a side collision, the impact load causes the multiple closed sections 16a, 16b, and 16c to collapse and deform, thereby improving energy absorption by the reinforcement 15.

[0058] This disclosure is not limited to the embodiments described herein, and various improvements and design modifications are possible without departing from the spirit of this disclosure.

[0059] [Note 1] Floor panel and Side sills are connected to both ends of the floor panel in the vehicle width direction and extend in the longitudinal direction of the vehicle body, A reinforcement is disposed inside the side sill and extends in the longitudinal direction of the vehicle body, A cross member is disposed on the upper surface of the floor panel and extends in the vehicle width direction, Equipped with, The cross member is positioned to overlap with the reinforcement in a vehicle side view, and the upper surface of the outer end of the cross member in the vehicle width direction is formed to slope upward from the inner side in the vehicle width direction to the outer side in the vehicle width direction. The lower body structure of the vehicle. [Note 2] The upper end of the cross member and the upper end of the reinforcement are positioned to overlap when viewed from the side of the vehicle. The lower body structure of the vehicle described in Appendix 1. [Note 3] The floor panel is provided with a battery housing that accommodates the battery below it. The aforementioned battery has a battery module, The cross member is formed such that the inner side of the outer end of the cross member in the vehicle width direction overlaps with the outer end of the battery module in the vehicle width direction in the vehicle width direction. The lower body structure of the vehicle described in Appendix 1 or Appendix 2. [Note 4] The cross member comprises an upper surface portion and side portions on both sides extending downward from the upper surface portion. The upper surface is provided with a recess that is recessed downwards, The upper surface of the outer end in the vehicle width direction of the bottom wall portion of the recess is formed to slope upward from the inner side in the vehicle width direction to the outer side in the vehicle width direction. The lower body structure of the vehicle described in any of the appendices 1 to 3. [Note 5] The reinforcement has a plurality of closed cross-sectional portions arranged in the vehicle width direction. The lower body structure of the vehicle described in any of the appendices 1 through 4. [Explanation of Symbols]

[0060] 1. Vehicle body 3 Batteries 3a Battery Module 4 Floor Panels 6 Battery housing 10 Side sill 15 Reinforcement 16,16a,16b,16c Closed section 30 Crossmember 31. Top surface (top surface of the cross member) 32 Side section (side section of the cross member) 35 recess 36 Bottom wall (bottom wall of the recess)

Claims

1. Floor panel and Side sills are connected to both ends of the floor panel in the vehicle width direction and extend in the longitudinal direction of the vehicle body, A reinforcement is disposed inside the side sill and extends in the longitudinal direction of the vehicle body, A cross member is disposed on the upper surface of the floor panel and extends in the vehicle width direction, Equipped with, The cross member is positioned to overlap with the reinforcement in a vehicle side view, and the upper surface of the outer end of the cross member in the vehicle width direction is formed to slope upward from the inner side in the vehicle width direction to the outer side in the vehicle width direction. The lower body structure of the vehicle.

2. The upper end of the cross member and the upper end of the reinforcement are positioned to overlap when viewed from the side of the vehicle. The lower body structure of the vehicle according to claim 1.

3. The floor panel is provided with a battery housing that accommodates the battery below it. The aforementioned battery has a battery module, The cross member is formed such that the inner side of the outer end of the cross member in the vehicle width direction overlaps with the outer end of the battery module in the vehicle width direction in the vehicle width direction. The lower body structure of the vehicle according to claim 1.

4. The cross member comprises an upper surface portion and side portions on both sides extending downward from the upper surface portion. The upper surface is provided with a recess that is recessed downwards, The upper surface of the outer end in the vehicle width direction of the bottom wall portion of the recess is formed to slope upward from the inner side in the vehicle width direction to the outer side in the vehicle width direction. The lower body structure of the vehicle according to claim 1.

5. The reinforcement has a plurality of closed cross-sectional portions arranged in the vehicle width direction. The lower body structure of the vehicle according to claim 1.

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