JP7316508B2 - vehicle undercarriage - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle lower structure including a tank protection member that protects a fuel tank from collision with an object colliding from the rear of the vehicle, and an undercover that straightens the running wind that flows behind the vehicle from the fuel tank.

2. Description of the Related Art Conventionally, in a vehicle such as an automobile that uses the output of an internal combustion engine as a driving force, a fuel tank that stores fuel such as gasoline is often provided between left and right side sills.
On the other hand, instead of the conventional internal combustion engine, in an electric vehicle that uses the output of a rotating electric machine as driving force, instead of a fuel tank, a relatively large battery unit that supplies electric power to the rotating electric machine is installed between the left and right side sills. are arranged.

Furthermore, some electric vehicles are equipped with an internal combustion engine for power generation in order to extend the cruising range. In the case of such an electric vehicle, the fuel tank is often arranged between the left and right rear side frames located behind the side sills of the vehicle (see Patent Document 1).

By the way, in a vehicle in which the fuel tank is arranged between the rear side frames, the fuel tank is located in the rear of the vehicle compared to the fuel tank arranged between the side sills. It is necessary to improve the protection performance of the fuel tank that protects the tank.

Therefore, it is conceivable to provide a relatively high-rigidity tank protection member that covers and protects the fuel tank, instead of, for example, the hydrogen tank undercover that covers the fuel tank of Patent Document 1.
At this time, in order to ensure the function of the undercover to rectify the running wind, the front end of the bottom surface of the undercover located at the vehicle rear of the fuel tank is fixed to the tank protection member, etc., so that the bottom surface of the undercover , is arranged so as to be continuous with the bottom surface of the tank protection member.

However, in this case, the inside of the undercover is exposed when viewed from the front of the vehicle, so there is a risk that air resistance will increase due to the flow of running wind from the front of the vehicle into the inside of the undercover. .
Furthermore, flying objects such as pebbles and snow not only enter the undercover, but also accumulate inside the undercover, applying an unintended load to the undercover, which may cause the undercover to fall off. was there.

JP 2009-96438 A

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a vehicle lower structure that can prevent an undercover from coming off without impairing the function of rectifying running wind.

The present invention is a vehicle lower structure comprising a pair of left and right rear side frames extending in the vehicle front-rear direction, a cross member connecting the rear side frames in the vehicle width direction, and an undercover covering the cross member at the rear of the vehicle. a fuel tank disposed in front of the vehicle of the cross member, a vehicle body frame member in front of the fuel tank, and the cross member are connected to each other through the vehicle lower side of the fuel tank; and a tank protection member for protecting the fuel tank from collision objects, the tank protection member having a plurality of fastening fixing portions fastened and fixed to the bottom surface of the cross member at predetermined intervals in the vehicle width direction. The undercover comprises a pair of left and right side mounting portions attached to the bottom surface of the rear side frame, a front portion erected between the side mounting portions and forming a front surface, and the tank protection member. Between the fastening and fixing portions, a front attachment portion extending forward of the vehicle from the front surface portion and attached to the bottom surface of the cross member; and a protective member covering portion that covers the fastening and fixing portion from below the vehicle .

According to the present invention, it is possible to prevent the undercover from coming off without impairing the function of rectifying running wind.
Specifically, the fastening and fixing portion of the tank protection member and the front mounting portion of the undercover are fixed to a cross member with relatively high rigidity, and the side mounting portion of the undercover is fixed to the rear side frame with relatively high rigidity. Therefore, the lower structure of the vehicle can secure mounting rigidity of the tank protection member and mounting rigidity of the undercover.

At this time, since the front mounting portion of the undercover is provided so as to be positioned between the fastening and fixing portions of the tank protection member, the lower structure of the vehicle is connected between the cross member and the undercover by the tank protection member. The vicinity of the location can be protected from flying objects from the front and sides of the vehicle.

Furthermore, since the undercover has a front portion that is erected between the side mounting portions, the lower structure of the vehicle has the bottom surface of the undercover formed so as to be continuous with the bottom surface of the tank protection member. Even so, it is possible to prevent the inside of the undercover from being exposed when viewed from the front of the vehicle.

Therefore, in the lower structure of the vehicle, the front portion of the undercover prevents incoming objects from entering the undercover from the front of the vehicle.
Therefore, the lower structure of the vehicle can secure the mounting rigidity of the tank protection member and the mounting rigidity of the undercover, and can prevent the undercover from falling off without impairing the function of straightening the running wind.

Further, the present invention is characterized in that the undercover is integrally formed with the front attachment portion and includes a protection member covering portion that covers the fastening and fixing portion of the tank protection member from below the vehicle.
According to the present invention, the vehicle lower structure can prevent moisture such as rainwater splashed toward the fastening and fixing portion of the tank protection member from adhering to the fastening and fixing portion. Therefore, the vehicle lower structure can prevent water from entering the cross member without providing a water stop member that closes the gap between the fastening portion of the tank protection member and the cross member.

As a result, the lower structure of the vehicle can prevent corrosion in the vicinity of the fastening and fixing portion of the tank protection member, so that the strength of the connection between the tank protection member and the cross member can be stably ensured.
Therefore, the lower structure of the vehicle can prevent the undercover from coming off, and can ensure stable fuel tank protection performance by the protective member covering portion of the undercover.

As an aspect of the present invention, the front attachment portion of the undercover is attached to the bottom surface of the cross member at a position in the vehicle front-rear direction substantially the same as the fastening fixing portion of the tank protection member, and the front surface of the undercover is attached to the bottom surface of the cross member. The portion may include a recessed portion formed by recessing a range from the base portion of the front attachment portion to the lower end of the front surface portion toward the rear of the vehicle.

According to the present invention, in the vehicle lower structure, the rigidity of the front surface of the undercover can be improved by the concave portion, so that bending deformation of the front surface of the undercover due to running wind from the front of the vehicle can be suppressed. Therefore, the lower structure of the vehicle can prevent unnecessary load from being applied to the vicinity of the attachment point between the front attachment portion of the undercover and the cross member.

Furthermore, the lower structure of the vehicle can secure a space for inserting a tool for fixing the undercover to the cross member by means of the concave portion of the front portion. Therefore, in the vehicle lower structure, the front portion of the undercover can be brought closer to the tank protection member in the vehicle front-rear direction.

As a result, in the lower vehicle body structure of the vehicle, the bottom surface of the undercover can be brought closer to the bottom surface of the tank protection member in the longitudinal direction of the vehicle. be able to.

Therefore, in the lower structure of the vehicle, the rigidity of the undercover can be improved, and the rectifying function of the undercover can be ensured without impairing the ease of assembly of the undercover to the cross member .

Moreover , as an aspect of the present invention, the undercover may include a member covering portion that covers a joint portion between the rear side frame and the cross member from below the vehicle.
According to the present invention, the vehicle lower structure can prevent water such as rainwater splashed toward the joint between the rear side frame and the cross member from adhering to the joint between the rear side frame and the cross member.

As a result, the lower structure of the vehicle can suppress corrosion in the vicinity of the joint between the rear side frame and the cross member, so that joint strength between the rear side frame and the cross member can be stably secured.

Therefore, in the vehicle lower structure, for example, the cross member stably prevents movement of a collision object from the rear of the vehicle to the front of the vehicle as the rear collision progresses, and in cooperation with the tank protection member, Contact between the collision object and the fuel tank can be prevented.
Therefore, the lower structure of the vehicle can prevent the undercover from coming off, and more stable fuel tank protection performance can be ensured by the member covering portion of the undercover.

Further, as an aspect of the present invention, the cross member includes a member body having a substantially hat-shaped cross-section projecting downward of the vehicle in a vertical cross-section along the longitudinal direction of the vehicle, and extending from the front and rear surfaces of the member body. a first joint portion joined to the vehicle width direction inner surface of the rear side frame; and a first joint portion extending from the bottom surface of the member body independently of the first joint portion, and a second joint portion joined to the bottom surface, and the member covering portion of the undercover is formed in a shape that integrally covers the first joint portion and the second joint portion of the cross member. good too.

According to the present invention, even when the rear side frame and the cross member are joined in a simple configuration, the under cover of the vehicle lower structure can ensure stable fuel tank protection performance.
Specifically, since the second joint portion extends independently of the first joint portion, the cross member, when joined to the rear side frame, is positioned between the first joint portion and the second joint portion. Gaps are likely to occur between them.

Therefore, the member covering portion of the undercover integrally covers the first joint portion and the second joint portion of the cross member, so that the joint portion between the rear side frame and the cross member of the vehicle lower structure is protected from rainwater, etc. can be prevented from being exposed to moisture.

As a result, the vehicle lower structure can not only suppress corrosion in the vicinity of the joint between the rear side frame and the cross member, but also suppress moisture from entering the interior of the cross member.

Therefore, even if the rear side frame and the cross member are joined with a simple structure, the lower structure of the vehicle is limited to the joint strength between the rear side frame and the cross member, It is possible to secure the fastening strength with the more stably.
Therefore, even when the rear side frame and the cross member are joined with a simple structure, the under cover of the vehicle lower structure can ensure stable fuel tank protection performance.

According to the present invention, it is possible to provide a vehicle lower structure capable of preventing the undercover from coming off without impairing the function of rectifying running wind.

The bottom view which shows the vehicle rear part in bottom view in a vehicle. FIG. 4 is a bottom view showing the rear portion of the vehicle with the undercover removed. FIG. 2 is an explanatory diagram for explaining a cross section taken along line AA in FIG. 1; BB arrow sectional view in FIG. FIG. 4 is an external perspective view of a main part showing the external appearance of the joint between the rear side frame and the rear floor cross member; Fig. 4 is a bottom view of a main part showing a joint portion between the rear side frame and the rear floor cross member in a bottom view; FIG. 2 is an external perspective view of a main part showing the external appearance of a reinforcing member; FIG. 3 is an external perspective view showing the external appearance of the undercover as viewed from the front and lower side of the vehicle;

An embodiment of the invention will be described below with reference to the drawings.
The vehicle of this embodiment is a vehicle having a fuel tank below the floor of the luggage compartment formed between the rear side frames. Such a vehicle lower structure will be described in detail with reference to FIGS. 1 to 8. FIG.

1 shows a bottom view of the rear part of the vehicle 1, FIG. 2 shows a bottom view of the rear part of the vehicle with the undercover 8 removed, and FIG. 3 shows a cross section taken along the line AA in FIG. 4 shows a cross-sectional view taken along the line BB in FIG. 1, and FIG. 5 shows an external perspective view of the main part of the joint between the rear side frame 2 and the second rear cross member 5. there is

Further, FIG. 6 shows a bottom view of the essential part of the joint between the rear side frame 2 and the second rear cross member 5, FIG. 7 shows an external perspective view of the essential part of the reinforcing member 57, and FIG. 10 shows an external perspective view of the undercover 8. FIG.
3(a) shows a cross-sectional view of the left side of the vehicle taken along the line AA in FIG. 1, and FIG. 3(b) shows a cross-sectional view of the right side of the vehicle taken along the line AA in FIG. there is

In the drawings, arrows Fr and Rr indicate the front-rear direction, with arrow Fr indicating the front and arrow Rr indicating the rear. Furthermore, the arrows Rh and Lh indicate the vehicle width direction, the arrow Rh indicates the right direction, and the arrow Lh indicates the left direction.

As shown in FIGS. 1 and 2, the vehicle 1 includes a pair of left and right rear side frames 2 extending in the front-rear direction of the vehicle at positions spaced apart by a predetermined distance in the vehicle width direction at the rear portion of the vehicle, and between the left and right rear side frames 2 . A rear floor panel 3, a first rear cross member 4 connecting the front portions of the left and right rear side frames 2 in the vehicle width direction, and a rear side frame 2 behind the first rear cross member 4 in the vehicle width direction. and a second rear cross member 5 that connects in the direction.

Further, the vehicle 1 includes a fuel tank 6 disposed between the first rear cross member 4 and the second rear cross member 5, and a tank protection member that protects the fuel tank 6 from collision with an object colliding from the rear of the vehicle. 7 and an undercover 8 made of synthetic resin that covers the rear floor panel 3 behind the second rear cross member 5 from below the vehicle.

As shown in FIG. 3, the rear side frame 2 is a closed cross-sectional member having a substantially rectangular cross-sectional shape in a vertical cross-section along the vehicle width direction, and includes an upper frame 21 positioned above the vehicle and an upper frame 21 positioned below the vehicle. It is configured with a lower frame 22 .

As shown in FIG. 3, the upper frame 21 includes an inner flange portion 21a joined to the upper surface of the rear floor panel 3 and an end portion extending upward from the inner flange portion 21a in a vertical cross section along the vehicle width direction. After that, an upper surface portion 21b extending outward in the vehicle width direction and an outer flange portion 21c extending upward from the upper surface portion 21b are integrally formed.

On the other hand, as shown in FIG. 3, the lower frame 22 has a substantially gate-shaped cross-sectional shape in a vertical cross-section along the width direction of the vehicle, the cross-sectional shape of which is open at the top of the vehicle.
Specifically, as shown in FIG. 3, the lower frame 22 includes an inner flange portion 22a joined to the lower surface of the rear floor panel 3 and an end portion of the inner flange portion 22a in a vertical cross section along the vehicle width direction. An inner wall portion 22b extending downward in the vehicle, a bottom portion 22c extending outward in the vehicle width direction from the inner wall portion 22b, and an outer wall portion 22d extending upward in the vehicle from the rear floor panel 3 from the bottom portion 22c. is integrally formed.

In the rear side frame 2, the inner flange portion 21a of the upper frame 21 and the inner flange portion 22a of the lower frame 22 are joined to sandwich the edge of the rear floor panel 3, and the outer flange portion 21c of the upper frame 21 is connected to the lower frame. By being joined to the upper portion of the outer wall portion 22d of the frame 22, the vertical cross section along the vehicle width direction forms a substantially rectangular closed cross section.

Further, as shown in FIGS. 1 and 2, the bottom surface portion 22c of the lower frame 22 of the rear side frame 2 is provided with a fastener for fastening and fixing the undercover 8 (a cover side edge portion 84 of the undercover 8, which will be described later). Four insertion holes 2H through which the bolts 11 are inserted are formed at predetermined intervals in the longitudinal direction of the vehicle. A weld nut (not shown) with which the fastening bolt 11 inserted through the insertion hole 2H is screwed is joined to the upper surface of the bottom surface portion 22c.

As shown in FIG. 2, the four through-holes 2H, which are positioned furthest forward in the bottom view, are positioned in the vicinity of the front end of a second rear cross member 5, which will be described later, in substantially the same position in the longitudinal direction of the vehicle. An opening is formed, and the second insertion hole 2H counted from the front of the vehicle is formed at a position behind the vehicle relative to a reinforcing member 57, which will be described later.

Furthermore, the third insertion hole 2H counted from the front of the vehicle is formed at substantially the same position in the front-rear direction of the vehicle at substantially the center of the rear floor surface portion 33 of the rear floor panel 3, which will be described later, in the front-rear direction of the vehicle. A fourth insertion hole 2</b>H is formed in the vicinity of the rear end of the rear floor surface portion 33 of the rear floor panel 3 at substantially the same position in the longitudinal direction of the vehicle.

2 to 4, the rear floor panel 3 is a panel member that forms the floor of the luggage compartment of the vehicle 1 behind the floor of the compartment of the vehicle 1 (not shown). As shown in FIG. 4, the rear floor panel 3 is a sloped portion that extends rearward and upward of the vehicle from a rear end of a front floor panel (not shown) that forms the floor surface of the vehicle compartment in a longitudinal section along the longitudinal direction of the vehicle. 31, a substantially flat front floor portion 32 extending from the rear end of the slope portion 31 to a second rear cross member 5, which will be described later, and a substantially flat plate shape extending further from the front floor portion 32 toward the rear of the vehicle. It is integrally formed with the rear floor portion 33 .

As shown in FIGS. 2 and 4, in the rear floor surface portion 33 of the rear floor panel 3, a housing portion 33a capable of housing, for example, an in-vehicle audio power amplifier and in-vehicle tools is recessed toward the vehicle downward direction. . 2 and 4, the accommodating portion 33a has a generally long elliptical shape in a bottom view that is elongated in the vehicle width direction, and is positioned at a predetermined distance rearward of the vehicle with respect to the second rear cross member 5. recessed in the

As shown in FIGS. 2 and 4, the first rear cross member 4 has a substantially rectangular closed cross-sectional shape in a vertical cross-section along the longitudinal direction of the vehicle. It is composed of an upper cross member 41 and a lower cross member 42 which are arranged with the .

As shown in FIG. 4, the upper cross member 41 is joined to the upper surface of the slope portion 31, and together with the slope portion 31 of the rear floor panel 3, the cross-sectional shape of the vertical cross section along the longitudinal direction of the vehicle is substantially rectangular. is formed to form a closed cross section of

Specifically, as shown in FIG. 4, the upper cross member 41 has a substantially hat-shaped cross-sectional shape in a vertical cross-section along the vehicle front-rear direction that protrudes upward of the vehicle, and has a flange portion provided at the lower end thereof. is joined to the slope portion 31 of the rear floor panel 3 .

On the other hand, as shown in FIG. 4, the lower cross member 42 is joined to the lower surface of the slope portion 31 so as to face the upper cross member 41 with the slope portion 31 of the rear floor panel 3 interposed therebetween. As shown in FIG. 4, the lower cross member 42 and the inclined surface portion 31 of the rear floor panel 3 are formed so that the vertical cross section along the longitudinal direction of the vehicle forms a substantially rectangular closed cross section. there is

Specifically, as shown in FIG. 4, the lower cross member 42 has a substantially hat-shaped cross-sectional shape in a vertical cross-section along the vehicle front-rear direction and protrudes downward of the vehicle. is joined to the slope portion 31 of the rear floor panel 3 .

Also, as shown in FIG. 2, the second rear cross member 5 is joined to the rear lower surface of the front floor surface portion 32 of the rear floor panel 3 at a position spaced a predetermined distance rearward of the vehicle from the first rear cross member 4. It is

As shown in FIGS. 4 to 6, the second rear cross member 5 includes a member main body 51 having a substantially hat-shaped cross-sectional shape that protrudes downward from the vehicle in a vertical cross section along the vehicle front-rear direction; It is formed integrally with a front flange piece 52, a rear flange piece 53, and a bottom flange piece 54 extending from both ends in the vehicle width direction.
The member body 51 is formed to have a length in the vehicle width direction that is slightly shorter than the distance between the rear side frames 2 in the vehicle width direction.

As shown in FIG. 4, the member main body 51 has a bottom surface portion 51a that faces the rear floor panel 3 at a predetermined distance below the vehicle in a vertical cross section along the vehicle front-rear direction, and a bottom surface portion 51a. A front wall portion 51b extending upward from the front end of the vehicle, a front flange portion 51c extending forward of the vehicle from the front wall portion 51b and joined to the lower surface of the rear floor panel 3, and a rear end of the bottom portion 51a. and a rear flange portion 51e extending rearward of the vehicle from the rear wall portion 51d and joined to the lower surface of the rear floor panel 3 are integrally formed.

As shown in FIGS. 1 to 3, a rear support member 63 is disposed on the bottom surface portion 51a of the second rear cross member 5 at a predetermined interval in the vehicle width direction. It is fastened and fixed in the vicinity. Note that the rear support member 63 will be described later.

2 to 4, weld bolts 55 for fastening and fixing the undercover 8 (cover front edge portion 85 to be described later) are located on the bottom surface portion 51a rather than the fastening portion of the rear support member 63. It is joined to the upper surface on the outer side in the vehicle width direction.

In addition, as shown in FIGS. 1 to 3, the bottom surface portion 51a is welded with a weld nut 56 to which a fastening bolt 12 for fastening and fixing the tank protection member 7 (a fastening fixing portion 71 to be described later) is screwed. It is joined to the upper surface outside the bolt 55 in the vehicle width direction.

The fastening point of the rear support member 63 is positioned on the front side of the vehicle with respect to the substantially central position of the bottom surface portion 51a in the front-rear direction of the vehicle, and the weld nut 56 and the weld bolt 55 are positioned on the rear side of the vehicle. are doing.

As shown in FIGS. 5 and 6, the front flange piece 52 extends slightly outward in the vehicle width direction from the end of the front wall portion 51b in the vehicle width direction, and then extends toward the front of the vehicle. there is As shown in FIGS. 5 and 6, the front flange piece 52 extends forward of the vehicle with a length in the vertical direction of the vehicle that is shorter than the length of the front wall portion 51b in the vertical direction of the vehicle.

As shown in FIGS. 5 and 6, the rear flange piece 53 extends slightly outward in the vehicle width direction from the end of the rear wall portion 51d in the vehicle width direction, and then extends toward the rear of the vehicle. there is As shown in FIGS. 5 and 6, the rear flange piece 53 extends forward of the vehicle with a length in the vertical direction of the vehicle that is shorter than the length of the rear wall portion 51d in the vertical direction of the vehicle.

As shown in FIGS. 5 and 6, the bottom flange piece 54 extends outward in the vehicle width direction from the end of the bottom surface portion 51a in the vehicle width direction. As shown in FIG. 6, the bottom flange piece 54 extends in a substantially trapezoidal shape in a plan view with the short side on the outside in the vehicle width direction.

Since the second rear cross member 5 is configured as described above, the joint between the rear side frame 2 and the second rear cross member 5 is surrounded by the front flange piece 52, the bottom flange piece 54, and the rear side frame 2. A gap and a gap surrounded by the rear flange piece 53, the bottom flange piece 54, and the rear side frame 2 are formed.

At the joint between the rear side frame 2 and the second rear cross member 5, as shown in FIGS. is joined.

Specifically, as shown in FIGS. 3, 6, and 7, the reinforcing member 57 extends from the front wall portion 51b of the second rear cross member 5 to the inner wall portion 22b of the rear side frame 2, The range from the rear wall portion 51d of the rear cross member 5 to the inner wall portion 22b of the rear side frame 2 and the range from the bottom surface portion 51a of the second rear cross member 5 to the bottom surface portion 22c of the rear side frame 2 are integrated from below the vehicle. It is formed in a shape that covers the
In other words, the reinforcing member 57 is shaped to integrally cover the front flange piece 52, the rear flange piece 53, and the bottom flange piece 54 of the second rear cross member 5 from below the vehicle.

Further, the fuel tank 6 stores fuel such as gasoline that is supplied to an internal combustion engine that generates driving force or an internal combustion engine that generates electricity. As shown in FIGS. 2 and 4, the fuel tank 6 is arranged substantially in the center in the vehicle width direction between the first rear cross member 4 and the second rear cross member 5 when viewed from the bottom. It is supported by one rear cross member 4 and a second rear cross member 5 .

Specifically, as shown in FIGS. 2 and 4, the fuel tank 6 includes a tank body 61 that stores fuel, a front support member 62 that supports the front portion of the tank body 61, and a rear portion of the tank body 61. It is composed of two rear support members 63 for supporting.
As shown in FIGS. 2 and 4, the front support member 62 connects the front end of the tank body 61 and the bottom surface of the first rear cross member 4 in the vehicle front-rear direction near the center in the vehicle width direction. It is assumed that the front support member 62 is fastened to the tank body 61 and the first rear cross member 4 .

On the other hand, as shown in FIGS. 2 and 4, the rear support member 63 is positioned slightly outside the center in the vehicle width direction so that the rear end of the tank main body 61 and the bottom surface portion 51a of the second rear cross member 5 are positioned slightly outward in the vehicle width direction. are connected in the longitudinal direction of the vehicle. It is assumed that the rear support member 63 is fastened to the tank body 61 and the second rear cross member 5 .

As shown in FIGS. 2, 4 and 5, the tank protection member 7 is a pair of left and right fastening members fastened and fixed to the second rear cross member 5 at positions spaced apart by a predetermined distance in the vehicle width direction. A pair of left and right protection frames 72 extending from the fastening and fixing part 71 toward the front of the vehicle, and a protection panel 73 bridged between the left and right protection frames 72 .

As shown in FIG. 2, the fastening fixing portion 71 is fastened and fixed to the second rear cross member 5 so that the protective frame 72 is positioned outside the fuel tank 6 in the vehicle width direction in a bottom view.
Specifically, as shown in FIGS. 3 and 5 , the fastening fixing portion 71 is a substantially hat-shaped member that protrudes downward in the vehicle, and both ends in the vehicle width direction are connected to each other through fastening bolts 12 . It is fastened and fixed to a weld nut 56 provided on the bottom surface portion 51 a of the second rear cross member 5 .

The protective frame 72 is a closed cross-sectional member having a substantially rectangular cross-sectional shape along the vehicle width direction, and is joined to a portion of the fastening/fixing portion 71 that protrudes downward from the vehicle.
As shown in FIG. 4, the protection frame 72 includes a downwardly extending portion 72a extending downward in front of the vehicle from the fastening fixing portion 71 so as to pass under the vehicle below the fuel tank 6 in a side view, and a downwardly extending portion 72a. It is formed integrally with a forward extending portion 72b that gently curves from the portion 72a and extends toward the front of the vehicle.

Although detailed illustration is omitted, the front end of the protective frame 72 is fastened and fixed to, for example, a vehicle body frame member constituting the vehicle body of the vehicle 1 or a highly rigid member fastened and fixed to the vehicle body frame member. It is assumed that there is
As shown in FIGS. 2 and 4, the protection panel 73 is arranged in the vicinity of the rear end of the protection frame 72 so as to cover the vehicle rear side of the fuel tank 6 .

Specifically, as shown in FIGS. 2 and 4, the protective panel 73 is bridged so as to connect the downward extending portions 72a of the protective frame 72. As shown in FIGS. As shown in FIG. 4, the protection panel 73 is composed of an outer panel 73a positioned at the rear of the vehicle and joined to the rear surface of the downward extending portion 72a, and an inner panel 73b positioned at the front of the vehicle with respect to the outer panel 73a. It is

Further, an outer panel 73a of the protection panel 73 is formed with a plurality of beads projecting toward the vehicle rear side and extending in the vehicle width direction. Similarly, the inner panel 73b of the protection panel 73 is formed with a plurality of beads that face the beads of the outer panel 73a and protrude forward of the vehicle when joined to the outer panel 73a.

As shown in FIGS. 1, 4 and 8, the undercover 8 has a substantially box-like shape with an open upper side of the vehicle, and includes the left and right rear side frames 2, the second rear cross member 5, and the rear side frame. 2 is fixed to a rear bumper 9 (see FIG. 1) disposed rearward of the vehicle.

More specifically, as shown in FIGS. 1, 4, and 8, the undercover 8 is a substantially flat plate-shaped cover bottom portion disposed at a position spaced downward by a predetermined distance from the rear floor panel 3. 81, left and right cover side wall portions 82 extending upward from the vehicle width direction both ends of the cover bottom portion 81, a cover front portion 83 extending upward from the front end of the cover bottom portion 81, and a cover. A cover side edge portion 84 extending outward in the vehicle width direction from the upper end of the side wall portion 82, a cover front edge portion 85 extending forward of the vehicle from the upper end of the cover front portion 83, and the cover front edge portion 85 It is integrally formed with a member covering portion 86 having a cover side edge portion 84 extending forward of the vehicle.

1 and 4, the cover bottom portion 81 has a length in the vehicle width direction that is slightly shorter than the interval between the left and right rear side frames 2 in the vehicle width direction, and a length extending from the lower end of the rear bumper 9 to the second rear cross member 5. It is formed in a flat plate shape that is substantially rectangular in bottom view and has a length in the longitudinal direction of the vehicle that is slightly shorter than the length in the longitudinal direction of the vehicle.

As shown in FIG. 4, the cover bottom portion 81 is formed between the vicinity of the rear end of the front extending portion 72b of the protection frame 72 and the lower end of the rear bumper 9 positioned above the front extending portion 72b of the vehicle in a side view. , so that the rear end is located above the vehicle with respect to the front end along an imaginary straight line (not shown) connecting the two.

Further, as shown in FIGS. 1 and 8, the rear end of the cover bottom portion 81 is provided with an insertion hole 81H through which the fastening bolt 13 fixed to the lower end of the rear bumper 9 and the resin clip 14 are inserted. Apertures are formed at predetermined intervals in the direction.
In addition, as shown in FIGS. 1 and 8 , the cover bottom portion 81 has substantially elongated elliptical water droplets extending in the vehicle width direction substantially in the center in the vehicle width direction in the vicinity of the front end thereof and at both ends in the vehicle width direction. Three through holes 81a are formed along the vehicle front-rear direction.

As shown in FIGS. 1 and 8, the left and right cover side wall portions 82 are formed in a substantially flat plate shape extending from the edge of the cover bottom portion 81 in the vehicle width direction to the vehicle upper side and slightly outward in the vehicle width direction. It is As shown in FIG. 1, the cover side wall portion 82 is formed such that its upper end substantially coincides with the vehicle width direction inner end portion of the bottom surface portion 22c of the rear side frame 2 in a bottom view.

Further, as shown in FIG. 8, the cover side wall portion 82 is formed with two projecting portions 82a projecting outward in the vehicle width direction from the lower end to the upper end at positions spaced apart by a predetermined distance in the vehicle front-rear direction. ing.
As shown in FIGS. 1 and 4 , the cover front surface portion 83 is formed in a substantially flat plate shape that covers an opening on the front side of the vehicle formed by the left and right cover side wall portions 82 and the cover bottom surface portion 81 .

Specifically, as shown in FIGS. 4 and 8, the cover front surface portion 83 extends from the front end of the cover bottom surface portion 81 toward the rear end of the bottom surface portion 51a of the second rear cross member 5 toward the vehicle front and upward. is set.
Further, as shown in FIGS. 1, 4, and 8, the cover front surface portion 83 has two recessed portions 83a recessed rearward of the vehicle in a range from the vicinity of the lower end to the upper end in the vertical direction of the vehicle. It is formed at substantially the same position in the vehicle width direction at a fixed location between the front edge portion 85 and the second rear cross member 5 .

Specifically, as shown in FIGS. 1 and 8, the recessed portion 83a is recessed in a generally arcuate shape protruding rearward of the vehicle, and the length in the vehicle width direction gradually decreases from the upper end to the lower end. It is recessed like this.
As shown in FIGS. 1 and 8, the cover side edge portion 84 is formed in a substantially flat plate shape extending in the longitudinal direction of the vehicle from the rear end of the cover side wall portion 82 to the front end of the cover front edge portion 85 . . The cover side edge portion 84 is fastened and fixed to the rear side frame 2 via fastening bolts 11, as shown in FIG.

Specifically, as shown in FIGS. 1 and 8, the cover side edge portions 84 are located at the second, third, and fourth positions of the four insertion holes 2H provided in the rear side frame 2, counted from the front of the vehicle. Three insertion holes 84H are formed at predetermined intervals in the vehicle front-rear direction to allow the fastening bolts 11 to be inserted into the second insertion holes 2H.

As shown in FIGS. 1 and 8 , the cover front edge portion 85 extends from the upper end of the cover front surface portion 83 toward the front of the vehicle so as to connect the left and right cover side edge portions 84 . 1, 6 and 8, the cover front edge portion 85 is located in the vicinity of the center of the bottom surface portion 51a of the second rear cross member 5 in the vehicle front-rear direction. , extending from the upper end of the cover front portion 83 .

As shown in FIGS. 1 to 3 and 8, the cover front edge portion 85 has two front attachment portions 85a attached to the weld bolts 55 provided on the bottom surface portion 51a of the second rear cross member 5, and a tank front edge portion 85a. Two protective member covering portions 85b that cover the fastening fixing portion 71 of the protective member 7 from below the vehicle are integrally connected in the vehicle width direction.

Specifically, as shown in FIGS. 1 and 8, the front attachment portion 85a is positioned outside the rear support member 63 that supports the fuel tank 6 in the vehicle width direction when the second rear cross member 5 is attached to the front attachment portion 85a. , and is formed so as to be positioned inside the fastening and fixing portion 71 of the tank protection member 7 in the vehicle width direction.

An insertion hole 85H through which the weld bolt 55 of the second rear cross member 5 is inserted is formed in the front attachment portion 85a. The recessed portion 83a of the cover front surface portion 83 is recessed at the rear end of the front mounting portion 85a.

As shown in FIGS. 3 and 8, the protective member covering portion 85b projects downward from the vehicle at a portion facing the fastening/fixing portion 71 of the tank protective member 7 outside the front mounting portion 85a in the vehicle width direction. formed by
As shown in FIG. 6, the member covering portion 86 integrates the front flange piece 52, the rear flange piece 53, and the bottom flange piece 54 of the second rear cross member 5 with the reinforcing member 57 from below the vehicle in a bottom view. It is formed in a shape that covers

Specifically, as shown in FIGS. 1, 6, and 8, the member covering portion 86 integrally covers the front end of the cover side edge portion 84 and the vehicle width direction end portion of the cover front edge portion 85. , and extends toward the front of the vehicle with the length in the longitudinal direction of the vehicle up to the front end of the reinforcing member 57 .

The member covering portion 86 is formed with an insertion hole 86H for allowing the fastening bolt 11 to be inserted through the insertion hole 2H positioned furthest forward of the vehicle among the four insertion holes 2H provided in the rear side frame 2. ing.

Furthermore, as shown in FIGS. 6 and 8, the member covering portion 86 is erected upward along the front wall portion 51b of the second rear cross member 5 and the inner wall portion 22b of the rear side frame 2. An upright portion 86a is formed at the front end on the inner side in the vehicle width direction.

As described above, the pair of left and right rear side frames 2 extending in the vehicle front-rear direction, the second rear cross member 5 connecting the rear side frames 2 in the vehicle width direction, and the under cover 8 covering the rear of the vehicle of the second rear cross member 5 The lower structure of the vehicle 1 includes a fuel tank 6 disposed in front of the second rear cross member 5, and a tank protection member 7 for protecting the fuel tank 6 from a collision object from the rear of the vehicle. , the tank protection member 7 includes a plurality of fastening fixing portions 71 fastened and fixed to the bottom surface portion 51a of the second rear cross member 5 at positions spaced apart by a predetermined distance in the vehicle width direction, and the undercover 8 is attached to the rear side frame 2. a pair of left and right cover side edges 84 attached to the bottom surface 22c of the tank, a cover front surface 83 erected between the cover side edges 84 and forming a front surface, and a fastening fixing portion 71 of the tank protection member 7 In between, a front attachment portion 85a extending forward of the vehicle from the front surface portion 83 of the cover and attached to the bottom surface portion 51a of the second rear cross member 5 has a function of rectifying running wind. It is possible to prevent the undercover 8 from coming off without damaging it.

Specifically, the fastening fixing portion 71 of the tank protection member 7 and the front attachment portion 85a of the undercover 8 are fixed to the relatively high-rigidity second rear cross member 5, and the cover lateral edge of the undercover 8 is fixed. Since 84 is fixed to the rear side frame 2 having relatively high rigidity, the lower structure of the vehicle 1 can secure mounting rigidity of the tank protection member 7 and mounting rigidity of the undercover 8 .

At this time, since the front mounting portion 85a of the undercover 8 is provided so as to be positioned between the fastening and fixing portions 71 of the tank protection member 7, the lower structure of the vehicle 1 is secured by the tank protection member 7 to the second position. The vicinity of the joint between the rear cross member 5 and the undercover 8 can be protected from flying objects from the front and side of the vehicle.

Furthermore, since the under cover 8 has the cover front surface portion 83 erected between the side edge portions 84 of the cover, the lower structure of the vehicle 1 is formed so as to be continuous with the bottom surface of the tank protection member 7 . Even when the cover bottom surface portion 81 of the cover 8 is formed, it is possible to prevent the inside of the undercover 8 from being exposed when viewed from the front of the vehicle.

Therefore, in the lower structure of the vehicle 1 , the cover front surface portion 83 of the undercover 8 prevents incoming objects from entering the undercover 8 from the front of the vehicle.
Therefore, the lower structure of the vehicle 1 can secure the mounting rigidity of the tank protection member 7 and the mounting rigidity of the undercover 8, and can prevent the undercover 8 from falling off without impairing the function of rectifying the running wind. can.

Further, the front attachment portion 85a of the undercover 8 is attached to the bottom surface portion 51a of the second rear cross member 5 at substantially the same position in the longitudinal direction of the vehicle as the fastening fixing portion 71 of the tank protection member 7. The front surface portion 83 is provided with a recessed portion 83a formed by recessing the range from the base of the front mounting portion 85a to the lower end of the cover front surface portion 83 toward the rear of the vehicle. Since the rigidity of the portion 83 can be improved by the concave portion 83a, bending deformation of the cover front surface portion 83 of the undercover 8 due to running wind from the front of the vehicle can be suppressed. Therefore, the lower structure of the vehicle 1 can prevent unnecessary load from being applied to the vicinity of the attachment point between the front attachment portion 85 a of the undercover 8 and the second rear cross member 5 .

Further, in the lower structure of the vehicle 1 , the recessed portion 83 a of the cover front face portion 83 can secure a space for inserting a tool for fixing the undercover 8 to the second rear cross member 5 . Therefore, the lower structure of the vehicle 1 allows the cover front surface portion 83 of the undercover 8 to be close to the tank protection member 7 in the vehicle front-rear direction.

As a result, the lower vehicle body structure of the vehicle 1 allows the cover bottom surface portion 81 of the undercover 8 to be closer to the bottom surface of the tank protection member 7 in the longitudinal direction of the vehicle. can be reliably rectified by the cover bottom portion 81 of .

Therefore, in the lower structure of the vehicle 1, the rigidity of the undercover 8 can be improved, and the rectifying function of the undercover 8 can be ensured without impairing the ease of assembly of the undercover 8 to the second rear cross member 5. be able to.

In addition, the undercover 8 is integrally formed with the front mounting portion 85a, and is provided with the protection member covering portion 85b that covers the fastening fixing portion 71 of the tank protection member 7 from below the vehicle, so that the lower structure of the vehicle 1 can be It is possible to prevent moisture such as rainwater splashed toward the fastening and fixing portion 71 of the tank protection member 7 from adhering to the fastening and fixing portion 71 .

For this reason, the lower structure of the vehicle 1 does not need to provide a water stop member for closing the gap between the fastening fixing portion 71 of the tank protection member 7 and the second rear cross member 5 , thereby preventing water from entering the second rear cross member 5 . intrusion can be prevented.

As a result, the lower structure of the vehicle 1 can prevent corrosion in the vicinity of the fastening fixing portion 71 of the tank protection member 7, so that the connection strength between the tank protection member 7 and the second rear cross member 5 can be stably secured. can.
Therefore, the lower structure of the vehicle 1 can prevent the undercover 8 from coming off, and can ensure stable protection performance of the fuel tank 6 by the protective member covering portion 85b of the undercover 8. As shown in FIG.

Further, since the under cover 8 includes the member covering portion 86 that covers the joint portion between the rear side frame 2 and the second rear cross member 5 from below the vehicle, the lower structure of the vehicle 1 consists of the rear side frame 2 and the second rear cross member 5. Moisture such as rainwater splashed toward the joint with the cross member 5 can be prevented from adhering to the joint between the rear side frame 2 and the second rear cross member 5 .

As a result, the lower structure of the vehicle 1 can suppress corrosion in the vicinity of the joint between the rear side frame 2 and the second rear cross member 5, so that the joint strength between the rear side frame 2 and the second rear cross member 5 can be stabilized. can be secured.

Therefore, in the lower structure of the vehicle, for example, the second rear cross member 5 stably prevents movement of an impacting object, such as a collision object, from the rear side of the vehicle to the front side of the vehicle as the rear-end collision progresses, and the tank protection member 7 and the tank protection member 7 are provided. , the contact between the collision object and the fuel tank 6 can be prevented.
Therefore, the lower structure of the vehicle 1 can prevent the undercover 8 from coming off, and more stable protection performance of the fuel tank 6 can be ensured by the member covering portion 86 of the undercover 8 .

The second rear cross member 5 includes a member main body 51 having a substantially hat-shaped cross-sectional shape that protrudes downward from the vehicle in a vertical cross section along the longitudinal direction of the vehicle, a front wall portion 51b, and a rear wall portion of the member main body 51. A front flange piece 52 and a rear flange piece 53 extending from 51d and joined to the inner wall portion 22b of the rear side frame 2; The member covering portion 86 of the undercover 8 is configured with a bottom flange piece 54 extending from the bottom surface portion 51 a and joined to the bottom surface portion 22 c of the rear side frame 2 . 52, the rear flange piece 53, and the bottom flange piece 54 are integrally formed, the lower structure of the vehicle 1 is such that the rear side frame 2 and the second rear cross member 5 are joined in a simple configuration. Even in this case, the undercover 8 can ensure stable protection performance of the fuel tank 6 .

Specifically, since the bottom flange piece 54 extends independently of the front flange piece 52 and the rear flange piece 53, the second rear cross member 5, when joined to the rear side frame 2, A gap is likely to occur between the front flange piece 52 and the bottom flange piece 54 and between the rear flange piece 53 and the bottom flange piece 54 .

Therefore, the member covering portion 86 of the undercover 8 integrally covers the front flange piece 52, the rear flange piece 53, and the bottom flange piece 54 of the second rear cross member 5, so that the lower structure of the vehicle 1 can be configured as a rear side It is possible to prevent the joint between the frame 2 and the second rear cross member 5 from being exposed to moisture such as rainwater.

As a result, the lower structure of the vehicle 1 not only suppresses corrosion in the vicinity of the joint between the rear side frame 2 and the second rear cross member 5, but also suppresses the intrusion of moisture into the interior of the second rear cross member 5. can be done.

Therefore, even when the rear side frame 2 and the second rear cross member 5 are joined with a simple structure, the lower structure of the vehicle 1 is such that the joint strength between the rear side frame 2 and the second rear cross member 5 is Also, the fastening strength between the fastening fixing portion 71 of the tank protection member 7 and the second rear cross member 5 can be secured more stably.
Therefore, even when the rear side frame 2 and the second rear cross member 5 are joined in a simple configuration, the lower structure of the vehicle 1 ensures stable protection performance of the fuel tank 6 by the undercover 8. can be done.

In correspondence with the configuration of this invention and the above-described embodiments,
The cross member of the present invention corresponds to the second rear cross member 5 of the embodiment,
and so on,
The tank protection member corresponds to the tank protection member 7,
The bottom surface of the cross member corresponds to the bottom surface portion 51a of the second rear cross member 5,
The bottom surface of the rear side frame corresponds to the bottom surface portion 22c of the rear side frame 2,
The side mounting portion corresponds to the side edge 84 of the cover,
The front part corresponds to the cover front part 83,
The front attachment portion corresponds to the front attachment portion 85a,
The first joint corresponds to the front flange piece 52 and the rear flange piece 53,
The second joint corresponds to the bottom flange piece 54, but
The present invention is not limited to the configurations of the above-described embodiments, and many embodiments can be obtained.

For example, in the above-described embodiment, the tank protection member 7 is composed of a pair of left and right fastening portions 71, a pair of left and right protection frames 72, and a protection panel 73. However, the tank protection member 7 is not limited to this. Any suitable tank protection member may be used as long as it can protect the fuel tank 6 from collisions with objects.

The undercover 8 has the cover front edge portion 85 in which the front mounting portion 85a and the protective member covering portion 85b are integrally formed, but the present invention is not limited to this. The covering portion 85b may be used as the protective member covering portion, and the undercover 8 may be independently formed.

In addition, although the protective member covering portion 85b that covers the fastening fixing portion 71 of the tank protective member 7 from below the vehicle is integrally formed with the cover front edge portion 85 of the undercover 8, the present invention is not limited to this. In addition to the covered portion 85b, the cover front edge portion 85 may be integrally formed with a portion that covers the fastening portion between the rear support member 63 that supports the fuel tank 6 and the second rear cross member 5 from below the vehicle.

In this case, the cover front edge portion 85 of the undercover 8 extends in the vehicle front-rear direction such that the front end is located in front of the vehicle relative to the vehicle front-rear direction approximate center of the bottom surface portion 51 a of the second rear cross member 5 . , the cover front edge portion 85 of the undercover 8 that faces the fastening portion between the rear support member 63 and the second rear cross member 5 projects downward from the vehicle, so that the rear support member 63 and the second rear cross member 5 are connected to each other. It may be configured to cover the fastening portion of.

Alternatively, the fastening portion 71 of the tank protection member 7 and the second rear cross member 5 are fastened together, and the undercover 8 and the second rear cross member 5 are fastened at substantially the same position in the longitudinal direction of the vehicle as the rear support. The member 63 and the second rear cross member 5 are fastened together, and the cover front edge 85 of the undercover 8 facing the fastening point between the rear support member 63 and the second rear cross member 5 protrudes downward from the vehicle. In addition, the fastening portion between the rear support member 63 and the second rear cross member 5 may be covered.

In addition, although the structure includes the reinforcing member 57 for reinforcing the joint between the rear side frame 2 and the second rear cross member 5, the structure is not limited to this, and the lower structure of the vehicle 1 does not include the reinforcing member 57. may

Also, the rear side frame 2 and the second rear cross member 5 are connected via the front flange piece 52, the rear flange piece 53, and the bottom flange piece 54 of the second rear cross member 5, but this is not limiting. As long as the rear side frame 2 and the second rear cross member 5 can be connected, they may be connected in an appropriate configuration.

REFERENCE SIGNS LIST 1 vehicle 2 rear side frame 5 second rear cross member 6 fuel tank 7 tank protection member 8 under cover 22c bottom portion 51 member main body 51a bottom portion 52 front flange piece 53 rear flange piece 54 Bottom flange piece 71 Fastening/fixing portion 83 Cover front portion 83a Recess portion 84 Cover side edge portion 85a Front mounting portion 85b Protective member covering portion 86 Member covering portion

Claims (4)

a pair of left and right rear side frames extending in the longitudinal direction of the vehicle;
a cross member that connects the rear side frames in the vehicle width direction;
A vehicle lower structure including an undercover that covers the vehicle rear of the cross member,
a fuel tank disposed in front of the cross member in the vehicle;
a tank protection member that connects a vehicle body frame member in front of the fuel tank and the cross member through the vehicle underside of the fuel tank and protects the fuel tank from a collision object from the rear of the vehicle;
The tank protection member is
a plurality of fastening fixing portions fastened and fixed to the bottom surface of the cross member at positions spaced apart by a predetermined distance in the vehicle width direction;
The undercover is
a pair of left and right side attachment portions attached to the bottom surface of the rear side frame;
a front portion erected between the side mounting portions and forming a front surface;
a front attachment portion extending forward of the vehicle from the front surface portion and attached to the bottom surface of the cross member between the fastening and fixing portions of the tank protection member ;
A lower structure for a vehicle, comprising: a protective member covering portion that is integrally formed with the front mounting portion and covers the fastening and fixing portion of the tank protective member from below the vehicle. the front mounting portion of the undercover,
attached to the bottom surface of the cross member at a position in the longitudinal direction of the vehicle that is substantially the same as the fastening and fixing portion of the tank protection member;
the front part of the undercover,
2. The substructure of a vehicle according to claim 1, further comprising a recess portion formed by recessing a range from the base portion of the front attachment portion to the lower end of the front surface portion toward the rear of the vehicle. The undercover is
a member covering portion covering a joint portion between the rear side frame and the cross member from below the vehicle;
The vehicle lower structure according to claim 1 or 2 . The cross member
a member main body having a substantially hat-shaped cross-section protruding downward from the vehicle in a vertical cross-section along the longitudinal direction of the vehicle;
a first joint portion extending from the front surface and the rear surface of the member main body and joined to the inner surface of the rear side frame in the vehicle width direction;
a second joint extending from the bottom surface of the member body independently of the first joint and joined to the bottom of the rear side frame;
The member covering portion of the undercover is
formed in a shape that integrally covers the first joint portion and the second joint portion of the cross member
4. The vehicle undercarriage according to claim 3 .

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