CN111434569A

CN111434569A - Lower structure of vehicle body

Info

Publication number: CN111434569A
Application number: CN202010020901.2A
Authority: CN
Inventors: 望月晋荣
Original assignee: Suzuki Motor Corp
Current assignee: Suzuki Motor Corp
Priority date: 2019-01-15
Filing date: 2020-01-09
Publication date: 2020-07-21
Anticipated expiration: 2040-01-09
Also published as: JP2020111243A; JP7206931B2; FR3091686A1; DE102020200320A1; JP7447980B2; DE102020200320B4; CN111434569B; FR3091686B1; JP2023024788A

Abstract

The invention provides a vehicle body lower part structure which can restrain deformation of a floor, disperse collision load and reduce plate vibration aiming at a structure with inclined floor longitudinal beams. Floor side members (31, 32) constituting a vehicle body lower structure have inward inclined portions (31b, 32b) inclined inward, and a reinforcement (40) has: an intermediate portion (44) that spans the floor tunnel (11); and outer inclined portions (41b, 42b) extending from both side portions of the intermediate portion (44) toward the inner inclined portions (31b, 32b), wherein flanges (44a, 44b) of the intermediate portion (44) are joined to an opening edge portion of the floor tunnel (11), outer flanges (41c, 42c) extending outward are provided on side portions of the outer inclined portions (41b, 42b), and the outer flanges (41c, 42c) are joined to the inner inclined portions (31b, 32 b).

Description

Lower structure of vehicle body

Technical Field

The present invention relates to a vehicle body lower portion structure.

Background

In order to improve the rigidity of the floor panel at the lower portion of the vehicle body, floor side members extending in the vehicle front-rear direction are joined to both vehicle width direction side portions of the floor panel. For example, in the case of a vehicle driven by a battery, the battery is provided on the floor panel.

Further, a vehicle body structural member constituting a vehicle body frame is joined to the floor panel. A structure serving as a vibration source, such as a driving motor and a suspension, is attached to the vehicle body structural member. Therefore, the vibration of the structure is transmitted to the floor via the vehicle body structural member.

On the other hand, in the case where a battery is mounted on a floor panel, in order to secure a space for installing the battery in the floor panel, for example, as disclosed in patent document 1, a structure is known in which a floor side member is inclined outward in the vehicle width direction as it goes toward the vehicle rear.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2015-151004

Disclosure of Invention

Problems to be solved by the invention

By inclining the floor side members as described above, the main floor portion becomes wide, and the installation area of the battery becomes large. However, in this inclined configuration, there is a possibility that: for example, the main floor portion is subjected to shear deformation, resulting in the front side member being liable to vibrate in the vehicle front-rear direction.

When the floor vibrates due to the transmission of the vibration, the floor becomes a cause of noise in the vehicle compartment. Further, when a frontal collision, an offset collision, or the like occurs, there is a possibility that the floor panel located inside the floor side members on both sides is deformed such as warped. That is, in the above-described structure, there is still room for improvement in terms of efficiently absorbing the collision load. In addition, even if only the reinforcing member is installed to cope with the warp, there is a possibility that a sufficient effect cannot be obtained.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a vehicle body lower portion structure that can suppress deformation of a floor panel and disperse a collision load to reduce the amplitude of panel vibration for a structure in which a floor side member is inclined with respect to the vehicle front-rear direction.

Means for solving the problems

To achieve the above object, a vehicle body lower portion structure of the present invention includes: a main floor disposed at a lower portion of a vehicle body; and floor side members joined to both sides in the vehicle width direction of a lower surface of the main floor, wherein a floor tunnel that opens downward in the vehicle and extends in the vehicle front-rear direction is provided in a vehicle width direction middle portion of the main floor. In the vehicle body lower structure, the floor side member includes: a straight portion extending in a vehicle front-rear direction; and an inner inclined portion extending from a front portion of the straight portion and inclined inward in the vehicle width direction toward the vehicle front, a reinforcement extending in the vehicle width direction being disposed on a lower surface side of the main floor, the reinforcement including: an intermediate portion spanning the floor tunnel; and an outer inclined portion extending from both vehicle-width-direction side portions of the intermediate portion toward the inner inclined portion, the intermediate portion and the outer inclined portion having a hat-shaped cross-sectional shape that opens toward a vehicle upper side, flanges being provided at front and rear portions of the intermediate portion and the outer inclined portion, respectively, the flanges of the intermediate portion being joined to an opening edge portion of the floor tunnel, an outer flange extending outward in the vehicle width direction being provided at a vehicle-width-direction outer side portion of the outer inclined portion, the outer flange being joined to the inner inclined portion.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, in a structure in which the floor side member is inclined with respect to the vehicle front-rear direction, deformation of the floor panel can be suppressed, the collision load can be dispersed, and the amplitude of the panel vibration can be reduced.

Drawings

Fig. 1 is a perspective view of a vehicle body lower portion structure of the present invention as viewed from below the vehicle.

Fig. 2 is an enlarged perspective view showing the reinforcement of fig. 1 and its periphery in an enlarged manner.

Fig. 3 is a bottom view showing the reinforcing member of fig. 2 and the periphery thereof.

Fig. 4 is a perspective view showing an upper surface side portion of the floor panel of fig. 3.

Fig. 5 is a perspective view of the floor panel of fig. 4 as viewed from the outside in the vehicle width direction.

Description of the reference numerals

10. A main floor; 11. a floor tunnel; 15. a step portion; 16. a lower surface (opening edge portion); 17. an upper layer surface; 18. a longitudinal wall surface; 21. a front longitudinal beam on the right side; 22. a left front side member; 23. suspending a frame; 24a, a right side sill; 24b, left side sill; 25. a front cross member; 26. a central member; 27. a right lateral member; 28. a left lateral member; 31. a floor stringer on the right side; 31a, a straight portion; 31b, an inner inclined portion; 32. a left floor stringer; 32a, a straight portion; 32b, an inner inclined portion; 40. a reinforcement; 41. a right outer inclined portion; 41a, anterior flange; 41b, a posterior flange; 41c, an outer flange; 41d, a front outer flange; 41e, a rear outer flange; 42. a left outer inclined portion; 42a, anterior flange; 42b, a posterior flange; 42c, an outer flange; 42d, a front outer flange; 42e, a rear outboard flange; 44. an intermediate portion; 44a, an anterior flange; 44b, a posterior flange; 51. 1 st floor beam; 51a, a front wall; 51b, a rear wall surface; 51c, anterior flange; 51d, a posterior flange; 51e, a top surface; 52. a 2 nd floor cross member; 53. a seat carrier; P11-P18 and welding points.

Detailed Description

An embodiment of a vehicle body lower portion structure according to the present invention will be described below with reference to the drawings (fig. 1 to 5). The vehicle body lower portion structure of the present embodiment is, for example, a structure of a vehicle body lower portion of an electric vehicle driven by a battery not shown.

In the figure, the direction of the arrow Fr indicates the front in the vehicle front-rear direction. The "front portion (front end) and the rear portion (rear end)" in the description of the embodiment correspond to the front portion and the rear portion in the vehicle front-rear direction. In addition, the right and left sides correspond to the left and right sides of the occupant when facing the front of the vehicle.

The vehicle body lower structure of the present embodiment has a main floor 10. A battery is provided on the lower surface side of the main floor 10. The vehicle body lower structure further includes:

front side members

21, 22; a front cross member 25;

floor stringers

31, 32; and a reinforcing member 40. In order to widen the space for mounting the battery, the

floor side members

31, 32 are spread in a shape of japanese kana ハ and joined to the

side sills

24a, 24 b. Details of these components are explained below.

The main floor 10 is a plate member disposed in a lower portion of a vehicle body, and as shown in fig. 1, is a plate-like member extending rearward of the vehicle from the vicinity of rear portions of left and right front wheels, not shown. The main floor 10 has a vehicle width direction dimension substantially corresponding to a vehicle width direction dimension of the vehicle body.

A floor tunnel 11 is provided in a substantially central portion (intermediate portion) of the main floor 10 in the vehicle width direction. The floor tunnel 11 opens downward of the vehicle and extends in the vehicle front-rear direction. The floor tunnel 11 is formed such that the vehicle width direction center portion of the lower surface of the main floor 10 is recessed upward in the vehicle when viewed from above.

In this example, the floor tunnel 11 is constructed by a member independent from the main floor 10. The members constituting the floor tunnel 11 have a hat-shaped sectional shape as viewed in the vehicle front-rear direction. The members constituting the floor tunnel 11 are joined to the opening edge portion on the upper surface side of the main floor 10 so as to close from above the opening portion of the main floor 10 provided at the vehicle width direction center and extending in the vehicle front-rear direction (fig. 5). Further, the upper surface of the main floor 10 may be deformed so as to bulge upward in the vehicle, and the floor tunnel 11 may be formed in the main floor 10 so as to integrate the floor tunnel 11 with the main floor 10.

As shown in fig. 2 and 3, the main floor 10 has a lower surface 16 positioned at an opening edge portion of the floor tunnel 11, and a stepped portion 15 extending toward the vehicle upper side with respect to the lower surface 16 is provided at the rear end of the floor tunnel 11. An upper deck 17 is provided on the vehicle rear side of the floor tunnel 11 so as to be located above the vehicle with respect to the lower deck 16, and the lower deck 16 and the upper deck 17 are connected by a vertical wall 18 that inclines upward of the vehicle as it goes toward the vehicle rear. The vertical wall surfaces 18 constituting the stepped portion 15 are located on both sides of the floor tunnel 11 in the vehicle width direction and extend in the vehicle width direction. The battery is provided on an upper surface 17 located behind the step 15, and illustration thereof is omitted.

As shown in fig. 1, the

front side members

21, 22 include a right front side member 21 and a left front side member 22, and the

front side members

21, 22 on both sides protrude and extend forward of the vehicle from the front portion of the main floor 10. The front side frames 21, 22 on both sides are disposed on the inside in the vehicle width direction of the left and right front wheels, not shown, in a pair of left and right, with a space therebetween in the vehicle width direction. Each of the

front side members

21, 22 is a highly rigid member constituting the vehicle body frame, and is formed of a metal material. A driving motor, not shown, for driving the wheels is disposed between the right front side frame 21 and the left front side frame 22.

As shown in fig. 1, the front cross member 25 is disposed on the lower surface side of the main floor 10 and extends in the vehicle width direction. As shown in fig. 2 and 3, the front cross member 25 has a center member 26, a right outer side member 27, and a left outer side member 28. The center member 26 extends in the vehicle width direction so as to cross the floor tunnel 11. Both vehicle width direction side portions of the center member 26 are joined to the lower face 16 positioned on both vehicle width direction sides of the floor tunnel 11 by spot welding or the like.

The rear portion of the center member 26 extends linearly in the vehicle width direction. The front portion of the center member 26 is inclined toward the vehicle front side as it goes toward the vehicle width direction outer side. That is, the vehicle longitudinal direction length of the center member 26 is set to: the length of the outer portion of the center member 26 in the vehicle width direction is greater than the length of the center portion of the center member 26 in the vehicle width direction.

The right outer member 27 is a member joined to the vehicle-widthwise rightward outer side portion of the center member 26 by spot welding or the like, and extends rightward and outward in the vehicle-widthwise direction from the vehicle-widthwise rightward outer side portion of the center member 26. The rear portion of the right outer member 27 extends linearly in the vehicle width direction so as to be continuous with the rear portion of the center member 26. The front portion of the right outer member 27 extends to be inclined toward the vehicle front side toward the vehicle width direction outer side so as to be continuous with the front portion of the center member 26. That is, the vehicle longitudinal direction length of the right outer member 27 is set to be longer toward the vehicle width direction outer side.

The vehicle-widthwise outer front portion of the right outer member 27 is joined to the lower surface of the rear portion of the right front side frame 21, and the vehicle-widthwise outer rear portion of the right outer member 27 is joined to the lower surface of an inner inclined portion 31b of a right floor side frame 31 described later. The joining of these members is performed by spot welding, for example. A welding point at which the vehicle width direction outer rear portion of the right outer member 27 is welded to the lower surface of the inner inclined portion 31b of the right floor side member 31 is indicated by P17 in fig. 2 and 3.

The left outer member 28 is joined to the vehicle-widthwise leftward outer portion of the center member 26 by spot welding or the like, and extends leftward and outward in the vehicle-widthwise direction from the vehicle-widthwise leftward outer portion of the center member 26. The rear portion of the left outer member 28 extends linearly in the vehicle width direction like the right outer member 27, and the front portion of the left outer member 28 is inclined. The vehicle-widthwise outer front portion of the left outer member 28 is joined to the lower surface of the rear portion of the left front side frame 22, and the vehicle-widthwise outer rear portion of the left outer member 28 is joined to the lower surface of an inner inclined portion 32b of a left floor side frame 32, which will be described later. A welding point at which the vehicle width direction outer rear portion of the left outer member 28 is welded to the lower surface of the inner inclined portion 32b of the left floor side member 32 is indicated by P18 in fig. 2 and 3.

The front cross member 25 is a highly rigid member constituting the vehicle body frame, like the

front side members

21, 22. The center member 26, the right outer member 27, and the left outer member 28 are formed of a metal material.

As shown in fig. 1, a suspension frame 23 is disposed on the vehicle front side of the front cross member 25. The suspension frame 23 is a highly rigid member that supports a suspension, not shown, and is joined to a rear portion of the right front side frame 21 and a rear portion of the left front side frame 22, etc., by spot welding or the like via brackets or the like.

Next, the

floor side members

31 and 32 will be explained. As shown in fig. 2 and 3, the floor frames 31 and 32 include a right floor frame 31 and a left floor frame 32. The floor frames 31 and 32 on both sides are arranged in a left-right pair at a distance from each other in the vehicle width direction.

The right floor side member 31 is a member disposed on the right outer side in the vehicle width direction of the lower surface of the main floor 10, and includes a linear portion 31a and an inner inclined portion 31 b. The straight portion 31a extends in the vehicle front-rear direction, and is joined to the right outer edge of the lower surface of the main floor 10 in the vehicle width direction by spot welding or the like, and is further joined to the right side sill 24a extending in the vehicle front-rear direction.

The inner inclined portion 31b is joined to the lower surface of the main floor 10, and extends from the front portion of the straight portion 31a while inclining inward in the vehicle width direction toward the front of the vehicle. The front portion of the inside inclined portion 31b is joined to the rear portion of the right front side member 21. The detailed illustration of the joint (welding point) is omitted. An angle formed by an inner wall surface of the inner inclined portion 31b on the inside in the vehicle width direction and an inner wall surface of the straight portion 31a on the inside in the vehicle width direction is an obtuse angle, and is about 150 degrees in this example. As described above, the right outer member 27 of the front cross member 25 is joined to the lower surface of the inner inclined portion 31b at the welding point P17 by spot welding or the like.

As shown in fig. 2 and 3, the left floor side member 32 is a member disposed on the left outer side in the vehicle width direction of the lower surface of the main floor 10, and has a linear portion 32a and an inner inclined portion 32b, similarly to the right floor side member 31. The straight portion 32a extends in the vehicle front-rear direction, and is joined to the left outer edge of the lower surface of the main floor 10 in the vehicle width direction, and is also joined to the left side sill 24 b. The inner inclined portion 32b is joined to the lower surface, and extends from the front portion of the straight portion 32a while inclining inward in the vehicle width direction toward the vehicle front. Further, the front portion of the inside inclined portion 32b is joined to the rear portion of the left front side member 22.

As described above, the vehicle width direction outer side portion of the left outer member 28 of the front cross member 25 is joined to the lower surface of the inner inclined portion 32b at the weld point P18 by spot welding or the like. The inside inclined portion 31b of the right floor side member 31 and the inside inclined portion 32b of the left floor side member 32 are disposed so as to approach each other as they go toward the vehicle front.

The floor frames 31, 32 include a 1 st member and a 2 nd member, the 1 st member constituting a main part of the

linear portions

31a, 32a, the 2 nd member constituting a part of the

linear portions

31a, 32a and the inside inclined

portions

31b, 32b, and the floor frames 31, 32 are formed by joining the 1 st member and the 2 nd member by spot welding or the like. The 2 nd member is constructed such that the front portions of the

linear portions

31a, 32a are bent and connected to the inner

inclined portions

31b, 32 b. In addition, illustration of the boundary between the 1 st member and the 2 nd member is omitted. The 1 st member and the 2 nd member may be integrally formed.

As shown in fig. 1 to 3, the reinforcement 40 is a member extending entirely in the vehicle width direction, and includes an intermediate portion 44, a right outer inclined portion 41, and a left outer inclined portion 42. In this example, the intermediate portion 44, the right outer inclined portion 41, and the left outer inclined portion 42 are integrally formed.

The intermediate portion 44, the right outer inclined portion 41, and the left outer inclined portion 42 have a hat-shaped cross-sectional shape that opens upward of the vehicle. In addition,

front side flanges

44a, 41a, 42a and

rear side flanges

44b, 41b, 42b are provided at the front and rear portions of the intermediate portion 44, the right outer inclined portion 41, and the left outer inclined portion 42, respectively. The

front flanges

44a, 41a, and 42a correspond to the front visor of the hat-shaped cross section, and the

rear flanges

44b, 41b, and 42b correspond to the rear visor of the hat-shaped cross section. The

flanges

41a, 42a, 44a, 41b, 42b, 44b are joined to the lower surface of the main floor 10 or the like. The joint position and the like will be described later.

The intermediate portion 44 extends in the vehicle width direction across the floor tunnel 11. The rear flange 44b of the intermediate portion 44 extends in the vehicle width direction. The front flange 44a of the intermediate portion 44 is inclined toward the vehicle front side as it goes toward the vehicle width direction outer side. The vehicle longitudinal direction length of the intermediate portion 44 in this example is set as follows: the length of the outer portion of the intermediate portion 44 in the vehicle width direction is greater than the length of the central portion of the intermediate portion 44 in the vehicle width direction.

Both vehicle width direction side portions of the front side flange 44a of the intermediate portion 44 are joined to the opening edge portion of the floor tunnel 11 at welding points P13, P14 shown in fig. 2 and 3 by spot welding or the like. Further, both vehicle width direction side portions of the rear side flange 44b of the intermediate portion 44 are also joined to the opening edge portion of the floor tunnel 11 at welding points P11, P12. The welding points P11, P12 of the rear flange 44b are adjacent to the vertical wall surface 18 constituting the stepped portion 15 on the vehicle front side with respect to the vertical wall surface 18. In this example, the welding points P11, P12 of the rear flange 44b are disposed at the rear corner of the opening edge of the floor tunnel 11.

As shown in fig. 2 and 3, the right outer inclined portion 41 extends obliquely from the vehicle width direction right side portion of the intermediate portion 44 toward the vehicle width direction outer side toward the vehicle front side. In this example, the angle formed by the front portion of the intermediate portion 44 and the front portion of the right outside inclined portion 41 is an obtuse angle, and is about 150 degrees. The right outer inclined portion 41 is substantially orthogonal to the inner inclined portion 31b of the right floor side member 31.

The front flange 41a and the rear flange 41b of the right outer inclined portion 41 are joined to the lower surface of the main floor 10 on the right side in the vehicle width direction of the floor tunnel 11 by spot welding or the like. The front flange 41a of the right outer inclined portion 41 is disposed at a distance from the front flange 44a of the intermediate portion 44. The rear flange 41b of the right outer inclined portion 41 is disposed at a distance from the rear flange 44b of the intermediate portion 44.

An outer flange 41c continuously extending outward in the vehicle width direction from an end of the lower surface is provided on an outer portion of the lower surface of the right outer inclined portion 41 in the vehicle width direction. The outer flange 41c is joined to the lower surface of the inner inclined portion 31b of the right floor side member 31 at the position of the welding point P15 by spot welding or the like. In fig. 2 and 3, only the welding point P15 is shown, but in this example, welding points are disposed at a plurality of positions spaced apart from the welding point P15.

Further, a rear outer flange 41e extending rearward of the vehicle from the rear wall is provided on the vehicle width direction outer side of the rear wall of the right outer inclined portion 41, and a front outer flange 41d extending forward of the vehicle from the front wall is provided on the vehicle width direction outer side of the front wall of the right outer inclined portion 41. The rear outer flange 41e connects the end of the rear flange 41b of the right outer inclined portion 41 to the rear portion of the outer flange 41c, and is joined to the inner wall of the right floor side member 31. The front outer flange 41d connects the end of the front flange 41a of the right outer inclined portion 41 to the front portion of the outer flange 41c, and is joined to the inner wall of the right floor side member 31.

As shown in fig. 2 and 3, the left outer inclined portion 42 extends from the intermediate portion 44 such that the left side portion in the vehicle width direction is inclined toward the vehicle front side toward the outside in the vehicle width direction, similarly to the right outer inclined portion 41. The left outside inclined portion 42 is substantially orthogonal to the inside inclined portion 32b of the left floor side member 32. The front flange 42a and the rear flange 42b of the left outer inclined portion 42 are joined to the lower surface of the main floor 10 on the left side in the vehicle width direction of the floor tunnel 11. The front flange 42a of the left outer inclined portion 42 is disposed at an interval from the front flange 44a of the intermediate portion 44, and the rear flange 42b of the left outer inclined portion 42 is disposed at an interval from the rear flange 44b of the intermediate portion 44.

Similarly to the right outer inclined portion 41, the left outer inclined portion 42 is also provided with an outer flange 42c, a rear outer flange 42e, and a front outer flange 42d, the outer flange 42c being joined to the lower surface of the left floor side member 32, and the rear outer flange 42e and the front outer flange 42d being joined to the inner wall of the left floor side member 32. In fig. 2 and 3, only the welding point P16 where the lower surface of the left inner inclined portion 32b and the outer flange 42c are welded is shown, but there are other welding points at other positions.

Since the reinforcement 40 has a hat-shaped cross-sectional shape, the reinforcement 40 and the main floor 10 form a closed cross-section, and the rigidity of the reinforcement 40 in the longitudinal direction (vehicle width direction) can be ensured. Further, the right and left outer

inclined portions

41, 42 of the reinforcement 40 are joined to the inner inclined portions 31b of the right and left floor frames 31, 32 in a substantially perpendicular state, whereby the floor frames 31, 32 can be supported to prevent the floor frames 31, 32 from collapsing.

In addition, since both vehicle-width-direction side portions of the intermediate portion 44 are joined to the opening edge portion of the floor tunnel 11 in order to reduce the deformation of the floor tunnel 11, the deformation of the main floor 10 can be further reduced, and the effects of dispersing the collision load and reducing the amplitude of panel vibration can be obtained.

The vehicle body lower portion structure of the present embodiment can suppress deformation of the entire vehicle body lower portion because deformation of the floor tunnel 11 is reduced in addition to deformation of the flat surfaces (the lower surface 16 and the upper surface 17) of the main floor 10. Further, by reducing the deformation of the floor tunnel 11, the load can be transmitted to the plane on the opposite side. As a result, the load dispersion can be promoted, the local deformation (stress) of the main floor 10 can be reduced, and the deformation of the vehicle body can be reduced as a whole.

Since the outer flange 41c of the right outer inclined portion 41 is joined to the lower surface of the inner inclined portion 31b of the right floor side member 31 and the outer flange 42c of the left outer inclined portion 42 is joined to the lower surface of the inner inclined portion 32b of the left floor side member 32, the position of the reinforcement 40 in the vehicle vertical direction can be matched to the floor side member. As a result, the area of the closed cross section formed by the main floor 10 and the reinforcement 40 is increased, and the

front side flanges

41a, 42a, and 44a and the

rear side flanges

41b, 42b, and 44b of the reinforcement 40 effectively function as load transmission paths. Further, since the corner portion of the stepped portion 15 is a highly rigid portion that is less likely to deform than the lower surface 16 and the upper surface 17 of the main floor 10, deformation of the floor tunnel 11 can be further reduced by joining the vehicle width direction outer side portion of the intermediate portion 44 of the reinforcement 40 to the corner portion.

As shown in fig. 4 and 5, a 1 st floor cross member 51 extending in the vehicle width direction is provided on the upper surface of the main floor 10 in the present embodiment. Further, at the upper surface, a 2 nd floor cross member 52 is provided on the vehicle rear side of the 1 st floor cross member 51. The 1 st floor cross member 51 and the 2 nd floor cross member 52 are disposed at a distance from each other in the vehicle front-rear direction.

As shown in fig. 4 and 5, the 1 st floor cross member 51 has a top surface 51e, a front wall surface 51a, a rear wall surface 51b, a front side flange 51c, and a rear side flange 51 d. The front wall surface 51a stands substantially perpendicular to the upper surface of the main floor 10 and extends in the vehicle width direction. The rear wall surface 51b is disposed at a position on the vehicle rear side with a space from the front wall surface 51a, stands substantially perpendicular to the upper surface of the main floor 10, and extends in the vehicle width direction. The top surface 51e connects the upper end of the front wall 51a with the upper end of the rear wall 51 b. A seat bracket 53 and the like are attached to the top surface 51 e.

The front flange 51c projects forward of the vehicle from the lower end of the front wall 51a and extends in the vehicle width direction. The rear flange 51d projects rearward of the vehicle from the lower end of the rear wall surface 51b and extends in the vehicle width direction. That is, the 1 st floor cross member 51 has a hat-shaped cross-sectional shape.

The front side flange (front portion) 51c of the 1 st floor cross member 51 is joined to the upper surface on the vehicle front side of the vertical wall surface 18 of the stepped portion 15, and the rear side flange (rear portion) 51d of the 1 st floor cross member 51 is joined to the upper surface on the vehicle rear side of the rear wall surface 51 b. That is, the 1 st floor cross member 51 is joined to the upper surface of the main floor 10 in a state straddling the step portion 15 in the vehicle front-rear direction.

As shown in fig. 3, the front flange 51c of the 1 st floor cross member 51, the

rear flanges

41b, 42b, and 44b of the reinforcement 40, and the lower surface 16 of the main floor 10 are joined to overlap in three layers. In fig. 3, the position of the 1 st floor cross member 51 is schematically shown by a broken line.

By providing the 1 st floor cross member 51 along the step portion 15 as described above, the reinforcement 40 ensures floor rigidity together with the 1 st floor cross member 51. Further, by joining the three layers in a superimposed manner, the load acting on the reinforcement 40 can be dispersed to the step portion 15 and the 1 st floor cross member 51. As a result, local deformation of the reinforcement 40 can be reduced, and deformation of the vehicle body lower portion can be suppressed.

In the present embodiment, as shown in fig. 2 and 3, the front cross member 25 is disposed across the floor tunnel 11. Further, a welding point P15 (joint portion) where the outer flange 41c of the outer inclined portion 41 of the reinforcement 40 is welded to the lower surface of the floor side member 31 and a welding point P17 (joint portion) where the inner inclined portion 31b of the floor side member 31 is welded to the outer member 27 of the front cross member 25 are adjacent in the inclination direction of the inner inclined portion 31b, and a welding point P16 (joint portion) where the outer flange 42c of the outer inclined portion 42 of the reinforcement 40 is welded to the lower surface of the floor side member 32 and a welding point P18 (joint portion) where the inner inclined portion 32b of the floor side member 32 is welded to the outer member 28 of the front cross member 25 are adjacent in the inclination direction of the inner inclined portion 32 b.

The reinforcement effect achieved by the reinforcement 40 that is open to the vehicle front side when viewed from above the vehicle can be increased by the front cross member 25. In general, the rigidity of the welded joint (joint) is improved because a plurality of members (panels) are stacked.

As described above, the welds P15 to P18 are adjacent in the oblique direction, and therefore the rigidity of the peripheries of the welds P15 to P18 is improved. As a result, the reinforcement effect by the front cross member 25 and the reinforcement 40 is improved. Further, although the periphery is deformed such as the floor side member collapses or the lower surface 16 warps as described above, the reinforcement 40 and the front cross member 25 can directly suppress the deformation and reduce the deformation of the floor tunnel 11.

The description of the embodiment is an example for explaining the present invention, and does not limit the invention described in the claims. The structure of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the scope of protection described in the claims.

In the reinforcement 40 of the above embodiment, the intermediate portion 44, the right outer inclined portion 41, and the left outer inclined portion 42 are integrally formed, but the present invention is not limited thereto. These members may be formed by separate members, and one reinforcing member 40 may be formed by joining them by welding or the like.

In the present embodiment, the electric vehicle in which the battery is provided on the upper surface 17 of the main floor 10 is described, but the present invention is not limited thereto. The vehicle body lower portion structure of the present embodiment can also be applied to a vehicle having an engine disposed between the front side frames 21, 22 on the front side of the main floor 10.

Claims

1. A vehicle body lower structure comprising: a main floor disposed at a lower portion of a vehicle body; and floor side members joined to both sides in the vehicle width direction of the lower surface of the main floor,

a floor tunnel that opens downward of the vehicle and extends in the vehicle front-rear direction is provided at a vehicle width direction intermediate portion of the main floor,

the vehicle body lower portion structure is characterized in that,

the floor stringer has: a straight portion extending in a vehicle front-rear direction; and an inner inclined portion extending from a front portion of the straight portion and inclined inward in the vehicle width direction toward the vehicle front,

a reinforcement extending in a vehicle width direction is disposed on a lower surface side of the main floor, and the reinforcement includes: an intermediate portion spanning the floor tunnel; and an outer inclined portion extending from both sides of the intermediate portion in the vehicle width direction toward the inner inclined portion,

the intermediate portion and the outside inclined portion have a hat-shaped cross-sectional shape open to the vehicle upper side, flanges are provided at front and rear portions of the intermediate portion and the outside inclined portion, respectively,

the flange of the intermediate portion is joined to an opening edge portion of the floor tunnel,

an outer flange extending outward in the vehicle width direction is provided at an outer portion of the outer inclined portion in the vehicle width direction, and the outer flange is joined to the inner inclined portion.

2. The vehicle body lower structure according to claim 1,

a step portion extending toward a vehicle upper side with respect to the opening edge portion of the floor tunnel is provided on the main floor located at a rear portion of the floor tunnel,

the flange of the intermediate portion is joined to the opening edge portion adjacent to the stepped portion,

the outer flange is joined to a lower surface of the inner inclined portion.

3. The vehicle body lower structure according to claim 2,

a floor cross member extending in the vehicle width direction is provided on the upper surface of the main floor,

a front portion of the floor cross member is joined to a vehicle front side of the stepped portion, a rear portion of the floor cross member is joined to a vehicle rear side of the stepped portion,

the front portion of the floor cross member, the flange of the reinforcement, and the main floor are joined into a triple overlap.

4. The vehicle body lower structure according to claim 2 or 3,

a front cross member extending in the vehicle width direction is disposed across the floor tunnel on a vehicle front side of the reinforcement, a vehicle width direction outer side portion of the front cross member is joined to the inner inclined portion of the floor side member,

a joint portion where the outer flange and a lower surface of the inner inclined portion are joined is adjacent to a joint portion where the inner inclined portion and the front cross member are joined.