Vehicle body lower part structure

Abstract

To provide a vehicle body lower part structure having a structure advantageous for suppressing vibration and noise while increasing rigidity of a floor panel on an upper surface side of the floor panel.SOLUTION: There is provided a vehicle body lower part structure 1 including: a floor panel 10 which is disposed above a power supply unit B in a vehicle body lower part; a front floor cross member 40 which is joined to the floor panel 10 and extends in a vehicle width direction while projecting toward a vehicle upper side; and a reinforcement member 60 which extends from the front floor cross member 40 toward a vehicle front side and is joined to an upper surface of the floor panel 10. In the vehicle body lower part structure 1, the reinforcement member 60 is bent along and joined to a panel front part 11, a panel inclined part 12, and a panel body part 13. In a region located on the vehicle front side relative to the front floor cross member 40, the panel body part 13 has: a flat part 14; and a bead part 15 which bulges toward the vehicle upper side relative to the flat part 14. Both edge parts in the vehicle width direction of the reinforcement member 60 are joined to the bead part 15.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] If a floor panel disposed under the vehicle body vibrates while the vehicle is traveling, noise may be generated inside the vehicle cabin. Therefore, in order to suppress the vibration of the floor panel, a structure for increasing the rigidity of the floor panel is often applied to the vehicle underbody structure.

[0003] As an example of a vehicle lower body structure having a structure for increasing the rigidity of a floor panel, the structure disclosed in Patent Document 1 is known. The structure disclosed in Patent Document 1 has a floor panel extending rearward from the lower end of a dash panel located at the front end of the vehicle interior, and a reinforcing panel and an above-floor member, which are strip-shaped members located on the floor panel and extend in the front-rear direction, and the reinforcing panel and the above-floor member are joined to a flat portion of the floor panel. On the underside of the floor panel, a recess protruding downward and an under-floor member having a relatively large cross section protruding downward are provided as part of the structure for increasing the rigidity of the floor panel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-137636 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, with the recent trend toward electrification of vehicles (EVs), it may be necessary to secure a space below the floor panel for disposing a power supply unit including a battery pack. However, in the structure disclosed in Patent Document 1, a recess and an underfloor member protrude downward on the underside of the floor panel, so it may be difficult to secure a sufficient space below the floor panel for disposing a power supply unit. Furthermore, in the structure disclosed in Patent Document 1, the reinforcement panel and the above-floor member are joined to the flat floor panel on the upper side of the floor panel to locally increase the rigidity, so that there are areas of low rigidity around the reinforcement panel, etc., of the floor panel, and these areas of low rigidity become antinodes of vibration, which may result in a disadvantageous structure in terms of suppressing vibration and noise.

[0006] SUMMARY OF THE PRESENT DISCLOSURE In view of the above, an object of the present invention is to provide a vehicle underbody structure that has a structure that is advantageous for suppressing vibration and noise while increasing the rigidity of the floor panel on the upper surface side of the floor panel. [Means for solving the problem]

[0007] In order to achieve the above-mentioned objective, according to one aspect of the present invention, a vehicle underbody structure is provided, comprising a floor panel arranged above a power supply unit in the underside of the vehicle body, a front floor cross member joined to the floor panel, protruding above the vehicle and extending in the vehicle width direction, and a reinforcing member extending from the front floor cross member toward the front of the vehicle and joined to an upper surface of the floor panel. In the vehicle body understructure, the floor panel has a panel front portion that constitutes the front portion of the floor panel, a panel inclined portion that extends diagonally from the rear edge of the panel front portion toward the rear and upper side of the vehicle, and a panel main body portion that extends from the rear edge of the panel inclined portion toward the rear of the vehicle, and the reinforcing member is bent to follow the panel front portion, the panel inclined portion, and the panel main body portion, and is joined to each of the panel front portion, the panel inclined portion, and the panel main body portion, and in an area located forward of the vehicle relative to the front floor cross member, the panel main body portion has a flat portion adjacent to the flat portion and a bead portion that bulges upward from the flat portion relative to the flat portion, and both vehicle width direction edges of the portion of the reinforcing member that follows the panel main body portion are joined to the bead portions. Effect of the Invention

[0008] According to one aspect of the present invention, it is possible to provide a vehicle underbody structure that has a structure that is advantageous for suppressing vibration and noise while increasing the rigidity of the floor panel on the upper surface side of the floor panel. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view of a vehicle underbody structure according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an enlarged top view of a main portion of the vehicle underbody structure. [Diagram 3] FIG. [Figure 4] 3 is a cross-sectional view taken along line AA shown in FIG. 2. [Diagram 5] 3 is a cross-sectional view taken along line BB shown in FIG. 2. [Figure 6] 3 is a cross-sectional view taken along line CC shown in FIG. 2. [Figure 7] FIG. 3 is a top view for explaining the shape of the floor panel in the main part of FIG. 2. [Figure 8] FIG. 8 is a cross-sectional view taken along line DD shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a perspective view of a vehicle body underbody structure 1 according to an embodiment of the present invention, Figs. 2 and 3 are views showing a main part of the vehicle body underbody structure 1, Fig. 2 is an enlarged top view, and Fig. 3 is a perspective view. In the drawings, the arrow Fr direction indicates the front in the vehicle longitudinal direction, the arrow O direction indicates the outside of the vehicle in the vehicle width direction, and the arrow U direction indicates the upper side in the vehicle vertical direction. In the following description, "front" and "rear" correspond to the front and rear in the vehicle longitudinal direction, "up" and "down" correspond to the up and down in the vehicle vertical direction, and "left" and "right" correspond to the left and right in the vehicle width direction when a passenger in the vehicle faces the front of the vehicle.

[0011] (Outline of the underbody structure) Referring to Fig. 1, the vehicle body understructure 1 includes a floor panel 10. A floor tunnel 20 is provided in the center (middle) of the floor panel 10 in the vehicle width direction. The vehicle body understructure 1 further includes a side sill 30, a front floor cross member 40, a rear floor cross member 50, and a reinforcing member 60. The vehicle body understructure 1 of this embodiment is applied to the structure of the vehicle body underside of an electric vehicle driven by a power supply unit B (see Figs. 6 and 8 described below, not shown in Figs. 4 and 5) including a battery pack.

[0012] The floor panel 10 is a panel member that constitutes the floor portion of the lower part of the vehicle body, and may also be called a main floor panel. In the illustrated example, the floor panel 10 is a plate-shaped member that extends from the lower part of the front part of the vehicle compartment toward the rear of the vehicle. The dimension of the floor panel 10 in the vehicle width direction approximately corresponds to the dimension of the vehicle body in the vehicle width direction. Note that in the vehicle body underbody structure 1, no member equivalent to an underfloor member of a conventional vehicle body underbody structure is provided on the underside of the floor panel 10.

[0013] The floor tunnel 20 is provided in the center (middle) of the floor panel 10 in the vehicle width direction. The floor tunnel 20 bulges out toward the top of the vehicle and extends in the vehicle front-rear direction. The floor tunnel 20 extends from the lower part of the front of the vehicle compartment through the front floor cross member 40 and the rear floor cross member 50 to the rear of the rear floor cross member 50.

[0014] In the illustrated example, the floor tunnel 20 is formed of a separate member from the floor panel 10. The floor tunnel 20 has a hat-shaped cross section that opens downward when viewed in the vehicle longitudinal direction. The floor tunnel 20 is joined to the opening edge portion 10a of the floor panel 10 so as to close from below the opening that is provided in the center of the floor panel 10 in the vehicle width direction and extends in the vehicle longitudinal direction. Specifically, the floor tunnel 20 has a tunnel bulge portion 21 that bulges outward in a roughly trapezoidal shape toward the upper side of the vehicle. A tunnel flange portion 22 that protrudes outward in the vehicle width direction is provided at the lower end of the side wall of the tunnel bulge portion 21. The tunnel flange portion 22 is joined to the lower surface of the opening edge portion 10a of the floor panel 10 by spot welding or the like.

[0015] The side sill 30 is provided on the outer edge of the floor panel 10 in the vehicle width direction and extends in the vehicle front-rear direction. The side sill 30 has a hat-shaped cross section that opens outward in the vehicle width direction. The outer surface of the vertical flange 10b on the outer edge of the floor panel 10 in the vehicle width direction is joined to the upper part of the inner wall 31a of the side sill 30 facing the inside in the vehicle width direction by spot welding or the like. The lower part of the side sill 30 protrudes downward from the lower surface of the floor panel 10.

[0016] Each of the front floor cross member 40 and the rear floor cross member 50 is a member that is joined to the floor panel 10 and protrudes upward from the vehicle and extends in the vehicle width direction. Each of the front floor cross member 40 and the rear floor cross member 50 intersects with the floor tunnel 20 from above and is joined to the floor tunnel 20 and the floor panel 10. The rear floor cross member 50 is disposed at a position spaced apart from the front floor cross member 40 toward the rear of the vehicle.

[0017] Each of the floor cross members (40, 50) has a hat-shaped cross section that opens downward when viewed in the vehicle front-rear direction. A middle portion of each of the floor cross members (40, 50) in the vehicle width direction is bent to fit along the floor tunnel 20.

[0018] The front floor cross member 40 has a first bulging portion 41, a first front flange 42, a first rear flange 43, and a first outer joint portion 44.

[0019] The first bulging portion 41 bulges upward of the vehicle and extends from the right side sill 30 to the left side sill 30. The first front flange 42 extends forward from the lower end of the front wall of the first bulging portion 41, and the first rear flange 43 extends rearward from the lower end of the rear wall of the first bulging portion 41, and each flange (42, 43) is joined to the upper surface of the floor panel 10 by spot welding or the like. The first outer joint 44 is a portion that constitutes the end of the front floor cross member 40 in the vehicle width direction (longitudinal direction), and is joined to the side sill 30 by spot welding or the like. The first outer joint 44 extends continuously to the top surface portion and the side wall portion of the first bulging portion 41, and is extended in the cross member width direction (vehicle front-rear direction). The first outer joint 44 is formed so as to follow the upper portion of the inner wall 31a of the side sill 30 and the upper wall 31b that extends from the upper end of the inner wall 31a to the outside in the vehicle width direction.

[0020] The rear floor cross member 50 has the same structure as the front floor cross member 40, and has a second bulge portion, a second front flange, a second rear flange, and a second outer joint portion corresponding to each element (41, 42, 43, 44) of the front floor cross member 40.

[0021] The reinforcing member 60 extends from the front floor cross member 40 toward the front of the vehicle and is joined to the upper surface of the floor panel 10. The shape and joining points of the reinforcing member 60 will be described later.

[0022] Here, the floor panel 10 is divided into a plurality of sections (1R1, 1R2, 1R3, 1L1, 1L2, 1L3) by the floor tunnel 20, the side sill 30, the front floor cross member 40, and the rear floor cross member 50. In other words, the floor panel 10 is divided into a plurality of sections (1R1, 1R2, 1R3, 1L1, 1L2, 1L3) in a plan view seen from above the vehicle by a plurality of high-strength members (20, 30, 40, 50) extending vertically and horizontally that constitute the skeletal members of the lower part of the vehicle body. In the illustrated example, the floor panel 10 is divided (sectioned) into six sections (1R1, 1R2, 1R3, 1L1, 1L2, 1L3).

[0023] In the following, the three right-hand compartments of the six compartments will be appropriately referred to as, from the front, right front compartment 1R1, right middle compartment 1R2, and right rear compartment 1R3, and the three left-hand compartments of the six compartments will be appropriately referred to as, from the front, left front compartment 1L1, left middle compartment 1L2, and left rear compartment 1L3.

[0024] In the vehicle body lower structure 1 of this embodiment, the structure described below is adopted for a target section, which is at least one section including the front part of the floor panel 10, among a plurality of sections divided by high-strength members (20, 30, 40, 50). In the illustrated example, the target sections are the right front section 1R1 and the left front section 1L1. In the illustrated example, the structure of the right front section 1R1 and the structure of the left front section 1L1 are the same except that they are symmetrical to each other. Below, the structure of the left front section 1L1 and its surroundings will mainly be described.

[0025] (Details of the underbody structure) Next, the detailed structure of the vehicle body underbody structure 1 will be described with a focus on the left front section 1L1 and its surrounding structure. Fig. 4 is a cross-sectional view taken along line AA in Fig. 2, Fig. 5 is a cross-sectional view taken along line BB in Fig. 2, Fig. 6 is a cross-sectional view taken along line CC in Fig. 2, and Fig. 7 is a top view for explaining the shape of the floor panel 10 in the main part of Fig. 2. Fig. 8 is a cross-sectional view taken along line DD in Fig. 7. Each of Figs. 2 to 8 shows a portion including the left front section 1L1. In Fig. 7, the reinforcing member 60 has been removed, and the outer shape of the reinforcing member 60 is shown by a two-dot chain line.

[0026] 4 to 6 and 8, in the vehicle body underbody structure 1, as described above, no member having a relatively large cross section equivalent to an underfloor member of a conventional vehicle body underbody structure is joined to the underside of the floor panel 10. A power supply unit B including a battery pack is disposed below the floor panel 10. In other words, the floor panel 10 is a member disposed above the power supply unit B including the battery pack in the vehicle body underside.

[0027] The space (allowable placement space) for placing the power supply unit B below the floor panel 10 extends outward in the vehicle width direction to the inner side surface in the vehicle width direction of the inner wall 31a of the side sill 30. In other words, in the vehicle body underbody structure 1, since a conventional underfloor member is not provided on the underside of the floor panel 10, the allowable placement space for the power supply unit B extends outward in the vehicle width direction to the outer edge of the floor panel 10 in the vehicle width direction.

[0028] Referring to FIGS. 2 to 8, the floor panel 10 has a panel front portion 11, a panel inclined portion 12, and a panel main body portion 13.

[0029] The panel front portion 11 is a portion that constitutes the front portion of the floor panel 10. The panel front portion 11 corresponds to an area where the feet of an occupant seated in the front seat are placed. In the illustrated example, the panel front portion 11 is divided into an installation portion 11a and a peripheral portion 11b.

[0030] The installation portion 11a is a generally trapezoidal region in which the inner edge in the vehicle width direction extends in the vehicle front-rear direction and the outer edge in the vehicle width direction is inclined when viewed from the vehicle up-down direction. The peripheral edge portion 11b is a region adjacent to the installation portion 11a on the front side of the installation portion 11a. In the illustrated example, the middle portion 11a1 in the vehicle width direction of the installation portion 11a is slightly recessed downward of the vehicle. The peripheral edge portion 11b is formed so as to continue from the front edge of the installation portion 11a and bulge slightly upward of the vehicle.

[0031] The panel inclined portion 12 extends obliquely toward the rear and upward of the vehicle from the rear edge of the panel front portion 11. In the illustrated example, the panel inclined portion 12 has a straight portion 12a and an outer portion 12b.

[0032] The straight portion 12a extends linearly from the floor tunnel 20 side toward the outside in the vehicle width direction. The straight portion 12a corresponds to an area where the heels of an occupant sitting in the front seat are placed. The outer portion 12b is an area that extends from the outer end of the straight portion 12a in the vehicle width direction toward the outside in the vehicle width direction and toward the rear of the vehicle. In the illustrated example, groove portions 12a1 recessed downward and rearward of the vehicle are formed in the straight portion 12a in the portions corresponding to the edges (step portions) on both sides in the vehicle width direction of the middle portion 11a1 of the installation portion 11a so as to run vertically through the straight portion 12a.

[0033] The panel main body 13 extends from the rear edge of the panel inclined portion 12 toward the rear of the vehicle. The panel main body 13 is located at a higher position (higher position) above the panel in the vertical direction of the vehicle relative to the panel front portion 11. In other words, the floor panel 10 has a stepped shape shifted in the vertical direction of the vehicle before and after the panel inclined portion 12. The panel main body 13 is connected to the panel front portion 11 via the panel inclined portion 12. The panel main body 13 occupies most of the area of ​​the floor panel 10. Focusing on the left front section 1L1, the panel main body 13 occupies most of the area of ​​the left front section 1L1.

[0034] The panel main body 13 has a flat portion 14 and a bead portion 15 in a region located in front of the vehicle relative to the front floor cross member 40. Although not particularly limited, in the illustrated example, focusing on the left front section 1L1, the flat portion 14 occupies approximately the same area as the bead portion 15.

[0035] The flat portion 14 of the panel main body 13 has flat surfaces that do not bulge (rise) in the vertical direction of the vehicle and extend in the front-rear direction and width direction of the vehicle without any irregularities. In the floor panel 10, the height position of the lower surface 14a of the flat portion 14 in the vertical direction of the vehicle is set to the same level over the entire surface. The opening edge portion 10a of the floor panel 10 is formed continuously with the flat portion 14 on the floor tunnel 20 side, and the vertical flange 10b of the floor panel 10 is formed continuously with the flat portion 14 on the side sill 30 side (outside in the vehicle width direction).

[0036] The bead portion 15 of the panel main body 13 is adjacent to the flat portion 14 and bulges upward relative to the flat portion 14. The bead portion 15 has a cross-sectional shape that bulges upward relative to the flat portion 14. Here, the flat portion 14 (more specifically, the lower surface 14a of the flat portion 14) is taken as the reference X for the height position in the vertical direction of the vehicle. In this case, the bead portion 15, the floor tunnel 20 (tunnel bulge portion 21), the front floor cross member 40, and the rear floor cross member 50 all bulge (protrude) upward relative to the flat portion 14 of the floor panel 10.

[0037] In this embodiment, the bead portion 15 has a front bead 16 and a rear bead 17. In the illustrated example, the bead portion 15 further has an intermediate bead .

[0038] The front bead 16 extends in the vehicle width direction and is formed in a generally rectangular shape extending in the vehicle width direction when viewed in the vehicle up-down direction (for example, in a plan view viewed from above the vehicle). In the illustrated example, the front bead 16 extends from the outer portion 12b of the panel inclined portion 12 to just before the opening edge portion 10a of the floor panel 10. Each of the outer portion 12c and the inner portion 12d of the panel inclined portion 12 in the vehicle width direction is continuous with the flat portion 14 of the panel main body portion 13.

[0039] In this embodiment, the front bead 16 is adjacent to the rear edge of the panel inclined portion 12. That is, the front bead 16 extends in the vehicle width direction at a position close to the front edge of the panel main body portion 13, and is formed so as to be continuous with the rear edge of the panel inclined portion 12. Specifically, the front bead 16 has a first front wall 161, a first outer wall 162, a first rear wall 163, a first inner wall 164, and a first upper wall 165. The first front wall 161 extends obliquely in continuation of the straight portion 12a of the panel inclined portion 12. The first outer wall 162 extends obliquely in continuation of the front portion of the outer portion 12b of the panel inclined portion 12. The first rear wall 163 extends inward in the vehicle width direction from the rear end of the first outer wall 162. The first inner wall 164 extends rearward in the vehicle from the inner end of the first front wall 161 in the vehicle width direction. The first upper wall 165 connects the upper edges of the first front wall 161, the first outer wall 162, the first rear wall 163, and the first inner wall 164, and faces generally upward of the vehicle. A more detailed structure of the front bead 16 will be described later.

[0040] The rear bead 17 is a bead located rearward of the front bead 16. The rear bead 17 is provided on the front floor cross member 40 side in an area of ​​the panel main body 13 that is forward of the front floor cross member 40. The rear bead 17 extends in the vehicle width direction behind the front bead 16. The overall length of the rear bead 17 in the vehicle width direction is roughly the same as the overall length of the front bead 16 in the vehicle width direction. The detailed structure of the rear bead 17 will be described later.

[0041] The intermediate bead 18 is a bead that connects an inner portion of the front bead 16 in the vehicle width direction to an inner portion of the rear bead 17 in the vehicle width direction. The intermediate bead 18 connects the front bead 16 to a first rear bead portion 17b (described later) of the rear bead 17. As a result, the front bead 16 is continuous with the first rear bead portion 17b via the intermediate bead 18.

[0042] Although not particularly limited, referring to Figure 3, the panel main body 13 is formed with multiple (two in the illustrated example) bulging portions 19a that bulge above the vehicle, separate from the bead portion 15, and with water drainage holes 19b.

[0043] Generally, the underside of the vehicle body must have a certain minimum ground clearance, which is the distance from the running surface to the bottom surface of the underside of the vehicle body. When the power supply unit is disposed below the floor panel, it is possible to offset the height position of the floor panel toward the interior of the vehicle from the viewpoint of ensuring the minimum ground clearance. However, this narrows the space inside the vehicle interior, which is undesirable from the viewpoint of ensuring the space inside the vehicle interior. When considering the securing of space inside the vehicle interior and the minimum ground clearance, it may be necessary to dispose the power supply unit as close as possible to the underside of the floor panel.

[0044] Regarding the placement of the power supply unit B, in the vehicle body understructure 1 of this embodiment, since no underfloor member is provided on the underside 14a of the floor panel 10 (flat portion 14) as in the past, the power supply unit B can be brought closer to the floor panel 10 by the height of the underfloor member. In this way, the vehicle body understructure 1 has a structure that allows the space for placing the power supply unit B below the floor panel 10 to be expanded in the vehicle width direction and toward the floor panel 10. Note that, with reference to Figures 6 and 8, the front end of the power supply unit B is located near the rear surface of the panel inclined portion 12.

[0045] Next, the structure of the reinforcing member 60 and the surrounding structure of the reinforcing member 60 will be described in detail.

[0046] As described above, the vehicle body underbody structure 1 includes the reinforcing member 60 that extends from the front floor cross member 40 toward the front of the vehicle and is joined to the upper surface of the floor panel 10. The reinforcing member 60 is made of a metal plate material, and in the illustrated example, is provided in the left front section 1L1 and the right front section 1R1. The reinforcing member 60 is a reinforcing plate that is provided on the upper surface side of the floor panel 10 and mainly functions to absorb impact loads from the front of the vehicle during a frontal collision, for example.

[0047] 1 to 3, the reinforcing member 60 has a predetermined width in the vehicle width direction and extends in the vehicle front-rear direction. The reinforcing member 60 is formed in a rectangular shape that is generally long in the vehicle front-rear direction when viewed in the vehicle up-down direction. In the illustrated example, the reinforcing member 60 extends in the vehicle front-rear direction in the vehicle width direction intermediate portion of the left front section 1L1 (right front section 1R1). Specifically, the reinforcing member 60 extends in the vehicle front-rear direction at a width direction position corresponding to the intermediate portion 11a1 of the installation portion 11a of the panel front portion 11 that is slightly recessed toward the vehicle lower side. The reinforcing member 60 has a width that is slightly shorter than the length of the intermediate portion 11a1 in the vehicle width direction. The reinforcing member 60 extends from the front floor cross member 40 to the peripheral portion 11b of the panel front portion 11, and crosses the rear bead 17, the front bead 16, the panel inclined portion 12, and the installation portion 11a.

[0048] The reinforcing member 60 is bent so as to fit along the panel front portion 11, the panel inclined portion 12, and the panel main body portion 13. In other words, the reinforcing member 60 has a first stepped portion 60a shifted in the vehicle up-down direction before and after a portion corresponding to the panel inclined portion 12. In the illustrated example, the reinforcing member 60 also has a second stepped portion 60b shifted in the vehicle up-down direction before and after a portion corresponding to the step between the installation portion 11a and the peripheral portion 11b.

[0049] The reinforcing member 60 is joined to each of the panel front portion 11, the panel inclined portion 12, and the panel main body portion 13. The reinforcing member 60 is joined to the upper surface of the floor panel 10 at a plurality of points spaced apart in the vehicle front-rear direction by spot welding or the like. Specifically, the front end portion 60c of the reinforcing member 60 is joined to the upper surface of the peripheral portion 11b of the panel front portion 11. The rear end portion 60d of the reinforcing member 60 is sandwiched between the first front flange 42 of the front floor cross member 40 and the flat portion 14 of the floor panel 10 (panel main body portion 13), and the first front flange 42, the rear end portion 60d, and the flat portion 14 are joined in a triple-layered manner. Then, both edge portions in the vehicle width direction of the reinforcing member 60 (first horizontal flange portion 62 and second horizontal flange portion 63 described later) are joined to the upper surface of the floor panel 10 at a plurality of points. In other words, the reinforcing member 60 runs along the floor panel 10 from the front floor cross member 40 to beyond the panel inclined portion 12 (step), and is joined at multiple points to both the panel main body portion 13 and the panel front portion 11.

[0050] 4 and 5, the reinforcing member 60 has a cross-sectional shape in which hat shapes that open downwardly of the vehicle are arranged side by side when viewed in the vehicle front-rear direction. Specifically, the reinforcing member 60 has a reinforcing main body portion 61 extending in the vehicle front-rear direction, a first horizontal flange 62 extending in the vehicle front-rear direction along one edge portion in the vehicle width direction of the reinforcing main body portion 61, and a second horizontal flange 63 extending in the vehicle front-rear direction along the other edge portion in the vehicle width direction of the reinforcing main body portion 61. The reinforcing main body portion 61 has a first reinforcing bead 61a extending along the first horizontal flange 62 and bulging upwardly of the vehicle, a second reinforcing bead 61b extending along the second horizontal flange 63 and bulging upwardly of the vehicle, and a reinforcing intermediate portion 61c connecting the first reinforcing bead 61a and the second reinforcing bead 61b.

[0051] Each of the first reinforcing bead 61a and the second reinforcing bead 61b bulges upward in a generally trapezoidal shape. In the illustrated example, the first reinforcing bead 61a and the second reinforcing bead 61b are formed in a symmetrical (left-right symmetrical) shape with respect to the vehicle width direction, and the first reinforcing bead 61a is located on the inner side of the vehicle width direction with respect to the second reinforcing bead 61b. The reinforcing intermediate portion 61c connects the lower end of the side wall on the outer side of the vehicle width direction of the first reinforcing bead 61a and the lower end of the side wall on the inner side of the vehicle width direction of the second reinforcing bead 61b. The first lateral flange 62 protrudes inward in the vehicle width direction from the lower end of the side wall on the inner side of the vehicle width direction of the first reinforcing bead 61a. The second lateral flange 63 protrudes outward in the vehicle width direction from the lower end of the side wall on the outer side of the vehicle width direction of the second reinforcing bead 61b.

[0052] Both vehicle width direction edge portions of the reinforcing member 60 that extend along the panel main body portion 13 are joined to at least the bead portions 15 of the panel main body portion 13. Each of the first and second horizontal flanges 62 and 63 of the reinforcing member 60 is joined to at least the bead portions 15 in the portions that extend along the panel main body portion 13. Specifically, each of the first and second horizontal flanges 62 and 63 of the reinforcing member 60 is joined to at least both the front bead 16 and the rear bead 17 in the portions that extend along the panel main body portion 13.

[0053] In this embodiment, the rear bead 17 of the bead portion 15 has a recessed portion 17a that crosses the rear bead 17 in the vehicle front-rear direction and is recessed toward the bottom of the vehicle, and the reinforcing member 60 extends at a position overlapping the recessed portion 17a of the rear bead 17.

[0054] In the illustrated example, the concave portion 17a is provided in a portion of the rear bead 17 that is located below the reinforcing body portion 61 of the reinforcing member 60. In the illustrated example, the concave portion 17a is recessed down to the flat portion 14, and the bottom surface of the concave portion 17a is formed by the upper surface of the flat portion 14.

[0055] In the illustrated example, the rear bead 17 has a first rear bead portion 17b and a second rear bead portion 17c that are separated (separated) from each other in the vehicle width direction by a concave portion 17a. That is, the rear bead 17 is interrupted in the middle in the vehicle width direction, and a flat portion 14 is provided between the first rear bead portion 17b and the second rear bead portion 17c. The first rear bead portion 17b is located on the inner side in the vehicle width direction with respect to the second rear bead portion 17c, and extends in the vehicle front-rear direction with a predetermined width in the vehicle width direction. The second rear bead portion 17c has a generally trapezoidal outer shape when viewed in the vehicle up-down direction. An inner wall 171 on the inner side in the vehicle width direction of the rear bead 17 (first rear bead portion 17b) is continuous with an inner wall 181 on the inner side in the vehicle width direction of the intermediate bead 18, and the inner wall 181 of the intermediate bead 18 is continuous with the first inner wall 164 of the front bead 16. The first rear bead portion 17b and the second rear bead portion 17c are not connected, but each of the first rear bead portion 17b and the second rear bead portion 17c extends so as to enter below the reinforcing member 60.

[0056] The reinforcing member 60 is joined to the first rear bead portion 17b and the second rear bead portion 17c in the portion corresponding to the rear bead 17. In the illustrated example, the vehicle width direction outer portion of the first rear bead portion 17b is recessed toward the vehicle lower side with respect to the vehicle width direction inner portion of the first rear bead portion 17b, and constitutes a first rear seat portion 172 that supports the first horizontal flange 62 of the reinforcing member 60. Similarly, the vehicle width direction inner portion of the second rear bead portion 17c is recessed toward the vehicle lower side with respect to the vehicle width direction outer portion of the second rear bead portion 17c, and constitutes a second rear seat portion 173 that supports the second horizontal flange 63 of the reinforcing member 60. The first horizontal flange 62 is joined to the upper surface of the first rear seat portion 172 in contact with the upper surface of the second rear seat portion 173 in contact with the upper surface of the second rear seat portion 173.

[0057] In this embodiment, the reinforcing member 60 has a rear joint portion 64 that is joined to the bottom surface of the concave portion 17a of the rear bead 17 and bulges downward of the vehicle. In the illustrated example, the rear joint portion 64 is formed in the reinforcing intermediate portion 61c of the reinforcing member 60, has a quadrangular pyramid-shaped outer shape, and bulges downward of the vehicle. In the illustrated example, the rear joint portion 64 is joined to a portion of the flat portion 14 between the first rear seat portion 172 (first rear bead portion 17b) and the second rear seat portion 173 (second rear bead portion 17c), which is the bottom surface of the concave portion 17a.

[0058] In the illustrated example, the reinforcing member 60 also has a first intermediate joint 65, a second intermediate joint 66, and a third intermediate joint 67. Each intermediate joint (65, 66, 67) bulges downward of the vehicle, is joined to a portion of the flat portion 14 between the front bead 16 and the rear bead 17, and bulges downward of the vehicle. The first intermediate joint 65 is formed in a position forward of the rear joint 64 in the reinforcing intermediate portion 61c. The second intermediate joint 66 is formed in a position between the front bead 16 and the rear bead 17 in the first horizontal flange 62, and the third intermediate joint 67 is formed in a position between the front bead 16 and the rear bead 17 in the second horizontal flange 63.

[0059] 4 and 5, a first overall height H1, which is the overall height of a portion of the reinforcing member 60 including the rear joint portion 64, is set higher (larger) than a second overall height H2, which is the overall height of a portion of the reinforcing member 60 corresponding to the front bead 16 (H1>H2). In other words, the overall height (first overall height H1) of the portion of the reinforcing member 60 overlapping with the recessed portion 17a is higher than the overall height (second overall height H2) of the portion of the reinforcing member 60 corresponding to the front bead 16. Specifically, in the portion of the reinforcing member 60 along the panel main body portion 13, the first horizontal flange 62, the second horizontal flange 63, and the reinforcing intermediate portion 61c basically extend parallel to the flat portion 14 at the same height position in the vehicle up-down direction, as shown in FIG. The bead height of the first reinforcing bead 61a (height from the first horizontal flange 62 to the bead apex) is the same as the bead height of the second reinforcing bead 61b (height from the second horizontal flange 63 to the bead apex). However, in the portion including the rear joint portion 64, as shown in Fig. 5, the reinforcing intermediate portion 61c protrudes downward from the first horizontal flange 62 and the second horizontal flange 63 by the amount of downward bulging of the rear joint portion 64. Although not shown, in the portion including each intermediate joint portion (65, 66, 67), the reinforcing intermediate portion 61c also protrudes downward from the first horizontal flange 62 and the second horizontal flange 63 by the amount of downward bulging of the intermediate joint portions (65, 66, 67). The first overall height H1 is the dimension from the lower surface of the rear joint 64 to the top surfaces of the first reinforcing bead 61a and the second reinforcing bead 61b, and the second overall height H2 corresponds to the bead height of the first reinforcing bead 61a and the second reinforcing bead 61b. Therefore, the relationship of first overall height H1 > second overall height H2 holds. Note that the overall height of the portion of the reinforcing member 60 including the intermediate joints (65, 66, 67) is the same as the first overall height H1.

[0060] In this embodiment, the front bead 16 extends so as to intersect with the reinforcing member 60 when viewed from above the vehicle. In other words, unlike the rear bead 17, the front bead 16 is continuous without interruption midway in the vehicle width direction and intersects with the reinforcing member 60.

[0061] 4, in the present embodiment, a curved surface portion 16a having a curvature and recessed downward is formed in the portion of the front bead 16 that intersects with the reinforcing member 60. The curved surface portion 16a is provided in a portion of the front bead 16 that is located below the reinforcing body portion 61 of the reinforcing member 60, similar to the recessed portion 17a.

[0062] 4, the front bead 16 is divided into a curved surface portion 16a, a first front bead portion 16b, and a second front bead portion 16c in the vehicle width direction. The first front bead portion 16b is located on the inner side of the second front bead portion 16c in the vehicle width direction. In the illustrated example, the outer portion of the first front bead portion 16b in the vehicle width direction is recessed downward from the inner portion of the first front bead portion 16b in the vehicle width direction, and constitutes a first front seat portion 166 that supports the first horizontal flange 62 of the reinforcing member 60. Similarly, the inner portion of the second front bead portion 16c in the vehicle width direction is recessed downward from the outer portion of the second front bead portion 16c in the vehicle width direction, and constitutes a second front seat portion 167 that supports the second horizontal flange 63 of the reinforcing member 60. The first horizontal flange 62 abuts against and is joined to the upper surface of the first front seat portion 166 , and the second horizontal flange 63 abuts against and is joined to the upper surface of the second front seat portion 167 .

[0063] The first front seat portion 166, the second front seat portion 167, the first rear seat portion 172, and the second rear seat portion 173 are disposed at the same height position in the vertical direction of the vehicle. In the illustrated example, the top surface of the front bead 16 (the first front bead portion 16b and the second front bead portion 16c), the top surface of the rear bead 17 (the first rear bead portion 17b and the second rear bead portion 17c), and the top surface of the reinforcing member 60 are disposed at the same height position in the vertical direction of the vehicle. In other words, the reinforcing member 60 does not protrude upward from the top surface of the bead portion 15 in the panel main body portion 13, and the space inside the vehicle is not narrowed due to the reinforcing member 60.

[0064] According to the vehicle body underbody structure 1 of this embodiment, (1) the floor panel 10 arranged above the power supply unit in the lower part of the vehicle body has a panel front part 11, a panel inclined part 12, and a panel main part 13, so that the floor panel 10 has a step-shaped part shifted in the vehicle up-down direction in front of and behind the panel inclined part 12, so that the range of the flat part 14 of the floor panel 10 is reduced, and the rigidity of the floor panel 10 is improved. (2) The reinforcing member 60 is bent so as to follow the panel front part 11, the panel inclined part 12, and the panel main part 13, and is joined to each of the panel front part 11, the panel inclined part 12, and the panel main part 13, and both edge parts in the vehicle width direction of the part of the reinforcing member 60 that follows the panel main part 13 are joined to the bead part of the panel main part 13. With this configuration, the reinforcing member 60 also has a step-shaped part (first step-shaped part 60a), and the rigidity of the reinforcing member 60 is also improved. And, because both edges in the vehicle width direction of the high-rigidity reinforcing member 60 having a stepped portion are joined to the bead portion 15 that is located higher than the panel front portion 11 of the floor panel 10, the rigidity in the vehicle vertical direction (vertical rigidity) of the floor panel 10 is effectively increased on the upper surface side of the floor panel 10. (3) Also, by joining the bead portion 15 to both edges in the vehicle width direction of the reinforcing member 60, the vibration level of the floor panel 10 near the joints is effectively reduced, and noise (sound radiated due to panel vibration) is also reduced.

[0065] As described above, the vehicle body understructure 1 according to this embodiment has a structure that is advantageous for suppressing vibration and noise while increasing the rigidity of the floor panel 10 on the upper surface side of the floor panel 10. Since the panel inclined portion 12 (straight portion 12a) corresponds to the area on which the heels of an occupant seated in the front seat are placed, forming a stepped portion at the front of the floor panel 10 is advantageous not only from the perspective of improving rigidity but also from the perspective of stability of the occupant's feet.

[0066] In this embodiment, the bead portion 15 has a front bead 16 and a rear bead 17, and the rear bead 17 has a concave portion 17a that cuts the rear bead 17 in the vehicle front-rear direction and is concave toward the vehicle lower side, and the reinforcing member 60 extends at a position overlapping the concave portion 17a. With this configuration, the overall height (first overall height H1) of the portion of the reinforcing member 60 that overlaps with the concave portion 17a can be made relatively high, and the rigidity of the reinforcing member 60 in the vertical direction is more effectively improved. In the illustrated example, the concave portion 17a is concave to the flat portion 14, so that the first overall height H1 can be further increased. In addition, in the illustrated example, the concave portion 17a that is concave to the flat portion 14 divides the rear bead 17 into left and right. As a result, the concave portion 17a functions as a flow path for discharging fluids such as electrodeposition liquid during manufacturing, and the discharge of liquid through the drainage holes 19b is promoted, which can contribute to improving manufacturing quality.

[0067] In this embodiment, the front bead 16 is adjacent to the rear edge of the panel inclined portion 12 and extends so as to intersect with the reinforcing member 60 when viewed from above the vehicle. With this configuration, the panel inclined portion 12 and the front bead 16 are integrated, and the vertical height of the step shape in the portion of the floor panel 10 including the panel inclined portion 12 is increased. As a result, the vertical rigidity of the step shape of the floor panel 10 is further increased, and vibration and noise are more effectively suppressed.

[0068] In this embodiment, the reinforcing member 60 has a rear joint 64 that is joined to the bottom surface of the recessed portion 17a and bulges out toward the bottom of the vehicle. With this configuration, the rear joint 64 suppresses vibration of the bottom of the recessed portion 17a of the floor panel 10 (in the illustrated example, the flat portion 14). Furthermore, by increasing the overall height (first overall height H1) of the reinforcing member 60 in the portion on the front floor cross member 40 side that is relatively prone to vibration, rigidity in the vertical direction is easily maintained.

[0069] In this embodiment, the overall height (first overall height H1) of the portion of the reinforcing member 60 including the rear joint 64 is set to be higher than the overall height (second overall height H2) of the portion of the reinforcing member 60 corresponding to the front bead 16. A stiffness difference occurs between the stiffness of the front portion and the stiffness of the rear portion of the floor panel 10 and the reinforcing member 60, and the vibration modes can be intentionally shifted so that they do not match between the front portion and the rear portion.

[0070] In this embodiment, a curved surface portion 16a having a curvature and recessed downward is formed at the portion of the front bead 16 that intersects with the reinforcing member 60. This configuration makes it easy to make the rigidity of the front bead 16 different from the rigidity of the rear bead 17, so that the local natural frequency of the floor panel 10 can be easily adjusted and noise (radiated sound) can be effectively reduced.

[0071] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-mentioned embodiment, and further modifications and changes are possible based on the technical concept of the present invention.

[0072] For example, in this embodiment, the main parts of the vehicle body underbody structure 1 (bead portion 15 and reinforcing member 60) are applied to the left front section 1L1 and the right front section 1R1, but this is not limited to this and may be applied to only one of the left front section 1L1 and the right front section 1R1. [Explanation of symbols]

[0073] 1...Vehicle underbody structure 10…Floor panel 11…Front panel 12…Panel inclination 13... Panel body 14...Flat area 15…Bead section 16…Front bead 16a...Curved surface part 17…Rear bead 17a...Concave shape part 20…Floor tunnel 30…Side sill 40…Front floor cross member 50…Rear floor cross member 60…Reinforcing member 64...Posterior junction B…Power supply unit H1: First overall height (total height of the part including the rear joint of the reinforcing member) H2: Second overall height (overall height of the part of the reinforcing member that corresponds to the front bead)

Claims

1. A vehicle body underbody structure including: a floor panel arranged above a power supply unit in a vehicle body underbody; a front floor cross member joined to the floor panel, protruding above the vehicle and extending in a vehicle width direction; and a reinforcing member extending from the front floor cross member toward the front of the vehicle and joined to an upper surface of the floor panel, The floor panel has a panel front portion constituting a front portion of the floor panel, a panel inclined portion extending obliquely from a rear edge of the panel front portion toward the rear and upper side of the vehicle, and a panel main body portion extending toward the rear of the vehicle from the rear edge of the panel inclined portion, the reinforcing member is bent so as to follow the panel front portion, the panel inclined portion, and the panel main body portion, and is joined to each of the panel front portion, the panel inclined portion, and the panel main body portion, the panel main body portion has, in a region located forward of the vehicle with respect to the front floor cross member, a flat portion and a bead portion adjacent to the flat portion and bulging upward with respect to the flat portion, a bead portion formed on the panel body and connected to the reinforcing member, the bead portion being connected to the panel body and the reinforcing member being connected to the bead portion;

2. The bead portion has a front bead and a rear bead spaced from the front bead toward the rear of the vehicle, the rear bead has a recessed portion extending longitudinally through the rear bead in a vehicle front-rear direction and recessed downwardly of the vehicle, The reinforcing member extends at a position overlapping the recessed portion. The vehicle underbody structure according to claim 1 .

3. 3. The vehicle underbody structure according to claim 2, wherein the front bead is adjacent to a rear edge of the panel inclined portion and extends so as to intersect with the reinforcing member when viewed from above the vehicle.

4. The vehicle underbody structure according to claim 3 , wherein the reinforcing member has a rear joint portion that is joined to a bottom surface of the recessed portion and bulges out downwardly of the vehicle.

5. 5. The vehicle underbody structure according to claim 4, wherein an overall height of a portion of the reinforcing member including the rear joint is set higher than an overall height of a portion of the reinforcing member corresponding to the front bead.

6. 4. The vehicle underbody structure according to claim 3, wherein a curved surface portion having a curvature and recessed downward is formed at a portion of the front bead that intersects with the reinforcing member.

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