JP2023061812A - Vehicle body lower part structure - Google Patents

Abstract

To provide a vehicle body lower part structure that can divert a load due to snow or the like and prevent an under cover from being damaged when snow or the like enters the under cover.SOLUTION: A vehicle body lower part structure includes an under cover 7 covering a portion of a trailing arm 5 from below. The under cover 7 includes: a front cover portion 71 extending from a position ahead of the trailing arm 5 to a position in which a front portion 51 of the trailing arm 5 is covered; and a rear cover portion 72 extending rearward continuously from the center in a vehicle width direction of a rear end portion 71a of the front cover portion 71. The under cover 7 is fixed to a vehicle body 1 by a first tightening portion 73a arranged ahead of the rear end portion 71a and disposed on an outer side in the vehicle width direction of the trailing arm 5 and a second tightening portion 73b disposed behind the first tightening portion 73a and on an inner side in the vehicle width direction of the trailing arm 5.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle body lower structure.

In general, part of a pair of left and right trailing arms of a rear suspension and the underside of the vehicle body in front of the rear suspension are covered with an undercover (also called a floor undercover) (see, for example, Patent Document 1).

The vehicle body undersurface structure described in Patent Document 1 includes a flat front underfloor cover (46) for rectification and a rear underfloor cover (47) covering the undersurface of the vehicle body except for the tunnel portion. The rear floor undercover (47) is arranged below the trailing arm (51). The floor undercover (47) has an extension (47E) extending rearward below the torsion beam (52) integrally and continuously from the front portion of the rear suspension (50).

The rear end (47b) of the extension (47E) is suspended from the flange (47c) formed on the rear end (47b) to the corresponding rear floor panel (23) via the brace (29). It is fixed to the bracket (60).

Japanese Patent Application Laid-Open No. 2019-182320 (see FIGS. 2 and 4)

However, in the vehicle body undersurface structure described in Patent Document 1, the floor undercover (47) is fixed to the undersurface of the rear floor panel (23) via the brace (29) and the vertically extending bracket (60). It is
For this reason, the floor undercover (47) is not susceptible to intrusion of snow, ice, water, stones, gravel, mud, foreign matter, etc. (hereinafter referred to as "snow, etc.") into the floor undercover (47) during running. Snow or the like may adhere to the trailing arm (51) itself. In this case, the floor undercover (47) may be subjected to a load due to snow or the like, and may be cracked or damaged because the load cannot be absorbed.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a vehicle body lower structure that can prevent the undercover from being damaged by absorbing the load caused by snow or the like when snow or the like enters the undercover.

A vehicle body lower structure according to the present invention includes an undercover that covers a portion of a trailing arm from below, and the undercover extends from the front of the trailing arm to a position that covers the front portion of the trailing arm. a front cover portion; and a rear cover portion extending rearward continuously from a vehicle width direction central portion of a rear end portion of the front cover portion, wherein the under cover extends forward of the rear end portion. A first fastening portion disposed outside the trailing arm in the vehicle width direction, and a first fastening portion disposed rearward of the first fastening portion and provided inside the trailing arm in the vehicle width direction. It is fixed to the vehicle body by the second fastening portion.

According to the present invention, it is possible to provide a vehicle body lower structure that can prevent the undercover from being damaged by absorbing the load caused by the snow or the like when snow or the like enters the undercover.

1 is a bottom view of a main portion of a vehicle body showing an example of a vehicle body lower portion structure according to an embodiment of the present invention; FIG. FIG. 4 is a schematic enlarged left side view of a main part showing an installed state of a trailing arm and an undercover; It is an enlarged bottom view showing an undercover and an insulator. FIG. 4 is an enlarged plan view showing an undercover and insulators; 4 is an enlarged exploded perspective view of the undercover; FIG. FIG. 4 is an enlarged exploded perspective view of a main part of the undercover; FIG. 4 is an enlarged perspective view of a main part showing an installed state of the undercover; 4 is an enlarged rear view showing an undercover and an insulator; FIG. FIG. 4 is an enlarged side view of a main portion of the undercover;

A vehicle body lower structure according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9. FIG.
The direction of movement of the vehicle C is "forward", the backward direction is "rear", the vertically upward side is "up", the vertically downward side is "down", and the vehicle width direction is "left" and "right". .
The vehicle body lower structure of the vehicle C is configured substantially symmetrically. One of the left side and the right side of the vehicle C will be described below, and the description of the other side will be omitted as appropriate.

≪Vehicle≫
First, an example of a vehicle C to which the present invention is applied will be described before describing a vehicle body lower portion structure according to an embodiment of the present invention.
As shown in FIG. 1, the vehicle C is not particularly limited in type, type, etc., as long as it is an automobile having an undercover 7 on the lower portion 1b of the vehicle body. Hereinafter, the present invention will be described by taking a passenger car as an example of the vehicle C. FIG.

≪Car body≫
As shown in FIG. 1, the vehicle body 1 is for forming the vehicle C as a whole. As shown in FIG. 1 or FIG. 2, the vehicle body 1 includes metal body frames such as side sills 11, rear side frames 12, and rear pillars 13; It mainly includes a bumper face 16 and the like.

≪Car body lower structure≫
The vehicle body lower structure is configured with an undercover 7 . In addition, an insulator 8 (also referred to as a "floor heat baffle plate"), an undercover 7, a suspension device 2, a suspension arm cover 4, a side sill 11, a rear side frame 12, and a rear wheel house are mounted on the vehicle body lower portion 1b of the vehicle body rear portion 1a. 15, etc. are arranged. These members of the vehicle body lower portion 1b are installed as a pair on the left and right so as to extend in the front-rear direction, or to be horizontally arranged and installed substantially symmetrically.
Since the vehicle body lower portion 1b is substantially symmetrical as described above, the left side of the vehicle body 1 will be mainly described below, and the description of the right side of the vehicle body 1 will be omitted as appropriate.

<Side sill>
The side sill 11 shown in FIG. 1 or 2 extends in the longitudinal direction of the vehicle body from the lower end of the rear pillar 13 to the lower end of the front pillar (not shown). shape to form). The side sill 11 is arranged inside the vehicle body and has a substantially U-shaped vertical cross section and is made of a high-strength steel plate, and is arranged outside the vehicle body and has a substantially U-shaped vertical cross section. are joined to form a

<Insulator>
The insulator 8 is a heat insulating material provided along an exhaust pipe (not shown) for guiding exhaust gas to the rear of the vehicle. The insulator 8 extends in the front-rear direction at substantially the center of the undercover 7 in the vehicle width direction.

≪Under Cover≫
As shown in FIG. 1, the undercover 7 is a member that covers the fuel tank (not shown) and part of the trailing arm 5 from below. The undercover 7 comprises a left undercover 7A installed between the insulator 8 and the left side sill 11, and a right undercover 7B installed between the insulator 8 and the right side sill 11. In this manner, the undercover 7 is divided into left and right by the insulator 8 .
Note that the insulator 8 may be omitted. For this reason, the undercover 7 may not be divided into the left undercover 7A and the right undercover 7B, but may be one.

As shown in FIG. 3, the undercover 7 is formed by a substantially rectangular front cover portion 71 arranged on the front side, and a rear end portion of the front cover portion 71 so as to reduce the width in the left-right direction rearward. and a substantially hexagonal rear cover portion 72 . The vehicle width direction outer portions of the front cover portion 71 and the rear cover portion 72 are formed symmetrically with each other. The undercover 7 has a large number of small holes for draining water arranged in a grid pattern at appropriate intervals.

As shown in FIGS. 4 and 5, the upper surface 7a of the undercover 7 includes a first rib 7c, a second rib 7d, an uneven portion 7e, a rear flange portion 74, a cover rear wall portion 76, and a convex portion. A portion 77, a cover side wall portion 78, and a side wall flange portion 79 are integrally formed and reinforced.

The first rib 7c is composed of a plurality of reinforcing ribs extending in the vehicle width direction. The second ribs 7d are composed of a plurality of reinforcing ribs extending in a direction (front-rear direction) orthogonal to the plurality of first ribs 7c. The first ribs 7c and the second ribs 7d are formed on the front cover portion 71 and the rear cover portion 72 at suitable intervals and arranged in a grid pattern. The concave-convex portion 7e is composed of a plurality of convex portions and concave portions formed at appropriate intervals in the left-right direction on the front end portions of the front cover portion 71 and the rear cover portion 72, respectively. For this reason, the cover bottom portion 75 is reinforced by the first rib 7c, the second rib 7d, and the uneven portion 7e and is difficult to bend.

As shown in FIG. 1 or FIG. 3, the undercover 7 is attached to the rear of the lower surface of the vehicle body 1 by a first fastening portion 73a, a second fastening portion 73b, a third fastening portion 73c, and a fourth fastening portion 73d. It is fixed in the near position.

<Front cover part>
As shown in FIG. 3 , the front cover portion 71 extends from the front of the trailing arm 5 to a first rear end portion 71 a (rear end portion) positioned to cover the front portion 51 of the trailing arm 5 . ing. As shown in FIG. 5, the front cover portion 71 includes a first rib 7c, a second rib 7d, an uneven portion 7e, a first fastening portion 73a, a third fastening portion 73c, and a fourth fastening portion 73d. , a cover bottom portion 75 , a cover rear wall portion 76 , a convex portion 77 , a cover side wall portion 78 and a side wall flange portion 79 are formed.
The first fastening portion 73a, the third fastening portion 73c, and the fourth fastening portion 73d will be described in detail later.

<Rear cover part>
As shown in FIG. 3, the rear cover portion 72 continuously extends rearward from the center portion of the first rear end portion 71a in the vehicle width direction to the second rear end portion 72b. As shown in FIG. 5, the rear cover portion 72 includes a first rib 7c, a second rib 7d, a second fastening portion 73b, a fourth fastening portion 73d, a rear flange portion 74, and a cover bottom portion 75. and are formed.

<Rear side flange>
The rear flange portion 74 is a portion for reinforcing the rear outer peripheral portion of the rear cover portion 72 . The rear flange portion 74 is a wall formed by bending upward the peripheral edge portions of the rear end portions of the left undercover 7A and the right undercover 7B.

As shown in FIG. 3, the cover bottom portion 75 has a lower surface 7b facing the road surface. The cover bottom portion 75 is configured by horizontally arranging the lower surface 7b of the left undercover 7A and the lower surface 7b of the right undercover 7B.

<Cover rear wall>
As shown in FIGS. 5 and 7, the cover rear wall portion 76 is a wall for preventing snow or the like from entering the undercover 7 (upper side of the undercover 7) during running. The cover rear wall portion 76 is formed of a protruding piece that protrudes upward from a position on the outside in the vehicle width direction of the first rear end portion 71a of the cover bottom portion 75 of the left undercover 7A and the right undercover 7B. The cover rear wall portion 76 is formed inward in the vehicle width direction from the rear end of the cover side wall portion 78 extending in the front-rear direction, and is formed in an L shape with respect to the cover side wall portion 78 in plan view. there is Therefore, the cover rear wall portion 76 can reinforce the first rear end portion 71a. As shown in FIG. 7 , the cover rear wall portion 76 is arranged outside the trailing arm 5 in the vehicle width direction. As shown in FIG. 9 , the height H2 of the cover rear wall portion 76 is formed lower than the height H1 of the cover side wall portion 78 .

<Cover side wall>
The cover side wall portion 78 is a wall that extends upward from the vehicle width direction outer front end portion of the front cover portion 71 of the left undercover 7A and the right undercover 7B to the first rear end portion 71a. The cover side wall portion 78 is formed so as to gradually increase in height from the front end portion to the rear end portion side, and is horizontally formed at the highest point near the first rear end portion 71a. A rear end portion of the cover side wall portion 78 extending in the front-rear direction is connected to an outer end portion of the cover rear wall portion 76 in the vehicle width direction. A reinforcing convex portion 77 is formed on the cover bottom portion 75 so as to protrude from the inner central portion of the cover side wall portion 78 in the vehicle width direction.

<Side wall flange>
The side wall flange portion 79 is horizontally bent outward in the vehicle width direction from the upper end of the cover side wall portion 78 of the left undercover 7A and the right undercover 7B, and is formed in an inverted L shape when viewed in longitudinal section. It is a part. The side wall flange portion 79 has a third fastening portion 73c at its front end and a first fastening portion 73a near its rear end. As shown in FIGS. 5 and 9, the upper surface of the side wall flange portion 79 has a gentle slope 79a that gently slopes forward from the front side, and a slightly steep slope 79b that slopes forward downward from the front side. and a substantially horizontal horizontal surface 79c. A first fastening portion 73a is provided on the inclined surface 79b.

<First fastening part>
As shown in FIG. 5, the first fastening portion 73a, the second fastening portion 73b, the third fastening portion 73c, and the fourth fastening portion 73d connect the undercover 7 (left undercover 7A and right undercover 7B) to the vehicle body 1. It is a place where fixing tools such as bolts for fixing are attached. The first fastening portion 73a is provided at a position near the rear end portion of the side wall flange portion 79 in the left undercover 7A and the right undercover 7B. For this reason, the first fastening portion 73a is arranged forward of the first rear end portion 71a and provided outside of the trailing arm 5 in the vehicle width direction. As shown in FIG. 9, the height H3 of the first fastening portion 73a is positioned lower than the height H4 of the second fastening portion 73b.

<Second fastening part>
As shown in FIG. 5, the second fastening portion 73b is provided at the tip of a protrusion 73b1 that protrudes upward from the cover bottom portion 75 above the highest horizontal surface 79c of the side wall flange portion 79. As shown in FIG. Reinforcing ribs 73b2 are formed on the front and rear side surfaces of the protrusion 73b1 in a bent state from a position near the upper end to the lower end. For this reason, the projection 73b1 is reinforced by being formed in a U-shape when viewed in cross section.
As shown in FIGS. 3 and 4, the front side of the second fastening portion 73b is formed with a cut groove 72a formed in a groove shape (U-shape) toward the inside in the vehicle width direction in plan view. It is

As shown in FIG. 7, the second fastening portion 73b is arranged behind the first fastening portion 73a and inside the trailing arm 5 in the vehicle width direction in the left undercover 7A and the right undercover 7B. It is As shown in FIGS. 3 and 7, a line connecting the first fastening portion 73a and the second fastening portion 73b is defined as a bending line L1 (virtual line). The rear ends of the cover rear wall portion 76, the cover side wall portion 78, and the rear end portion of the side wall flange portion 79, which are located outside the bending line L1 in the vehicle width direction, are not fixed to the vehicle body 1 by fasteners or the like. It is relatively easy to bend downward (in the direction of arrow a) about the bending line L1. Therefore, when snow or the like enters the undercover 7, the cover rear wall portion 76 can be bent so as to be tilted downward, so that the snow or the like can be removed.

<Third fastening part>
As shown in FIGS. 3 and 5, the third fastening portion 73c is provided at the front end portion of the side wall flange portion 79 in the left undercover 7A and the right undercover 7B.

<Fourth fastening part>
A plurality of fourth fastening portions 73d are provided at appropriate intervals in the front-rear direction at the vehicle width direction inner end portions of the left undercover 7A and the right undercover 7B.

≪Suspension device≫
The suspension device 2 shown in FIG. 1 is a buffer device that connects a rear wheel (not shown) and the vehicle body 1 and buffers impacts and vibrations from the road surface from being transmitted to the vehicle interior. The suspension device 2 comprises a suspension arm 3, a suspension arm cover 4, a trailing arm 5 and a stabilizer 6. The suspension device 2 is arranged behind the undercover 7 .

<Suspension arm and suspension arm cover>
The suspension arm 3 is a pair of left and right link-shaped members arranged at the rear lower portion of a carrier (not shown) that rotatably supports wheels (not shown). The suspension arm 3 consists of an arm member extending in the vehicle width direction.
The suspension arm cover 4 is a plate-like protective member that covers and protects the suspension arm 3 .

<Trailing arm>
The trailing arm 5 is a member that is connected to a carrier (not shown) to suspend wheels (not shown). The trailing arm 5 extends in the front direction of the vehicle from its carrier (not shown). A front end portion of the trailing arm 5 is connected to the vehicle body 1 via a rubber bush or the like so as to be swingable about an axis in the vehicle width direction.

<Stabilizer>
The stabilizer 6 is a rod-shaped torsion beam (stabilizer bar) made of spring steel that applies a spring reaction force to each cushion unit (not shown) in order to control the roll of the vehicle body 1 . Arm portions on both left and right sides of the stabilizer 6 are attached to the suspension arm 3 via bushes by couplings (not shown).

≪Action of the lower body structure≫
Next, the operation of the vehicle body lower portion structure according to the embodiment of the present invention will be described with reference to FIGS. 1 to 9. FIG.

As shown in FIG. 1 , while the vehicle is running, snow or the like on the road may bounce off the wheels (not shown) and enter the undercover 7 from the first rear end portion 71 a of the undercover 7 .

As shown in FIGS. 7 and 9 , a cover rear wall portion 76 is erected upward from a cover bottom portion 75 at a first rear end portion 71 a of the undercover 7 . Therefore, snow or the like can be prevented from entering the undercover 7 .

As shown in FIG. 1, the periphery of the first rear end portion 71a of the undercover 7 is fixed to the vehicle body 1 by a first fastening portion 73a and a second fastening portion 73b. For this reason, the undercover 7 has a structure in which the portion behind the imaginary line (bending line L1) connecting the first fastening portion 73a and the second fastening portion 73b (outside portion in the vehicle width direction) relatively easily bends upward. It has become.

Further, as shown in FIGS. 7 to 9, in the undercover 7, the first fastening portion 73a fixed to the vehicle body 1 is arranged at a position lower than the second fastening portion 73b. Therefore, the undercover 7 can be easily bent so that the bending line L1 is tilted outward in the vehicle width direction from the first rear end portion 71a outside the trailing arm 5 .

By making the height H2 of the cover rear wall portion 76 lower than the height H1 of the cover side wall portion 78, the cover rear wall portion 76 can have lower rigidity than those of the same height. The periphery of the wall portion 76 can be made easier to bend.

Further, as shown in FIGS. 4 to 6, the undercover 7 is reinforced by forming a plurality of first ribs 7c and a plurality of second ribs 7d on the upper surface 7a substantially over the entire surface. It has a structure that makes it difficult to bend.

Therefore, when snow or the like enters the undercover 7, the portion behind the bending line L1 of the undercover (the outer portion in the vehicle width direction) is likely to bend downward, so that the snow can be removed. The under cover 7 is deformed without being cracked when a load is applied. Therefore, the load due to snow or the like can be relieved (released).

Thus, the vehicle body lower part structure according to the embodiment of the present invention includes the undercover 7 that covers a portion of the trailing arm 5 from below, as shown in FIG. 1 or FIG. A front cover portion 71 extending from the front of the arm 5 to a position covering the front portion 51 of the trailing arm 5, and a first rear end portion 71a (rear end portion) of the front cover portion 71 continuous from the center portion in the vehicle width direction. and a rear cover portion 72 extending rearward, and the under cover 7 is disposed forward of the first rear end portion 71a (rear end portion) and is further forward than the trailing arm 5 in the vehicle width direction. The first fastening portion 73a provided on the outer side and the second fastening portion 73b disposed rearward of the first fastening portion 73a and on the inner side of the trailing arm 5 in the vehicle width direction allow the vehicle body 1 to Fixed.

According to this configuration, the vehicle body lower portion structure of the present invention includes the first fastening portion 73a provided outside the trailing arm 5 in the vehicle width direction and the second fastening portion 73a provided inside the trailing arm 5 in the vehicle width direction. The undercover 7 is fixed to the vehicle body 1 by the portion 73b. For this reason, the undercover 7 has a structure in which the portion behind the imaginary line (bending line L1) connecting the first fastening portion 73a and the second fastening portion 73b (outside portion in the vehicle width direction) is relatively easy to bend. be able to. As a result, when snow or the like enters the undercover 7, the portion behind the bending line L1 of the undercover 7 (outside in the vehicle width direction) is likely to bend downward. Therefore, it is possible to prevent the under cover 7 from cracking or breaking due to the load caused by it being removed. Further, the undercover 7 can be bent downward at a portion behind the bending line L1 of the undercover 7, so that snow or the like that has entered the undercover 7 can be easily removed.

Further, as shown in FIGS. 7 to 9, the first fastening portion 73a is arranged at a position lower than the second fastening portion 73b.

According to this configuration, the undercover 7 is provided with the height H3 of the first fastening portion 73a at a position lower than the height H4 of the second fastening portion 73b. 79 and the cover side wall portion 78 are positioned lower than the second fastening portion 73b. For this reason, the undercover 7 can be easily bent so that the portion outside the bending line L1 is tilted outward in the vehicle width direction with the bending line L1 as the center.

7 and 9, the front cover portion 71 includes a cover bottom portion 75 having a lower surface 7b facing the road surface, and a cover bottom portion 75 provided outside the trailing arm 5 in the vehicle width direction. and a cover rear wall portion 76 erected upward from the rear end portion 71a (rear end portion).

According to this configuration, the undercover 7 has the cover rear wall portion 76 provided outside the trailing arm 5 in the vehicle width direction. can be prevented from hitting Further, since the cover rear wall portion 76 is erected from the first rear end portion 71a, it is possible to prevent snow or the like from entering the undercover 7. As shown in FIG.

As shown in FIG. 8 or 9, the cover rear wall portion is provided upright from the front end portion on the outside in the vehicle width direction of the front cover portion 71 to the first rear end portion 71a (rear end portion). 76, and a side wall flange portion 79 extending outward in the vehicle width direction from the cover side wall portion 78. The first fastening portion 73a is provided on the side wall flange portion 79, A height H2 of the wall portion 76 is lower than a height H1 of the cover side wall portion 78 .

According to such a configuration, the cover side wall portion 78 below the side wall flange portion 79 is extended to the cover bottom portion 75 and held. By making the height H2 of the cover rear wall portion 76 lower than the height H1 of the cover side wall portion 78, the cover rear wall portion 76 can have lower rigidity than those of the same height. The periphery of the wall portion 76 can be made easier to bend.

4 to 6, the upper surface 7a of the undercover 7 has a plurality of first ribs 7c extending in the vehicle width direction and a plurality of first ribs 7c extending in a direction orthogonal to the plurality of first ribs 7c. and a plurality of second ribs 7d are formed.

According to this configuration, the undercover 7 has a plurality of first ribs 7c extending in the vehicle width direction and a plurality of second ribs 7d extending in the front-rear direction on the upper surface 7a. By arranging them, it is possible to reinforce the cover bottom portion 75 and make it difficult to bend.

[Modification]
It should be noted that the present invention is not limited to the above embodiments, and various modifications and changes are possible within the scope of its technical ideas, and the present invention does not extend to these modified and changed inventions. Of course.

In this embodiment, as shown in FIGS. 4 to 6, on the upper surface 7a of the undercover 7, a first rib 7c extending in the vehicle width direction and a first rib 7c extending in a direction orthogonal to the first rib 7c Although it has been described that the second ribs 7d are formed, the present invention is not limited to this.
A plurality of first ribs 7 c and a plurality of second ribs 7 d may be formed on the lower surface 7 b of the undercover 7 . Also in this way, the undercover 7 can be reinforced.

Also, the insulator 8 shown in FIG. 1 may be omitted.
Therefore, the undercover 7 may be made of a single metal plate integrated with the left undercover 7A and the right undercover 7B.

Reference Signs List 1 vehicle body 5 trailing arm 7 under cover 7a upper surface 7b lower surface 7c first rib 7d second rib 51 front portion 71a first rear end portion (rear end portion)
71 front cover portion 72 rear cover portion 73a first fastening portion 73b second fastening portion 75 cover bottom portion 76 cover rear wall portion 77 wall portion 78 cover side wall portion 79 side wall flange portion H1 height of cover side wall portion H2 cover rear wall portion Height H3 Height of first joint H4 Height of second joint

Claims (5)

Equipped with an under cover that covers part of the trailing arm from below,
The undercover is
a front cover portion extending from the front of the trailing arm to a position covering the front portion of the trailing arm;
a rear cover portion extending rearward continuously from a center portion in the vehicle width direction of the rear end portion of the front cover portion;
the undercover includes a first fastening portion disposed forward of the rear end portion and provided outside the trailing arm in the vehicle width direction;
a second fastening portion disposed rearward of the first fastening portion and provided inside the trailing arm in the vehicle width direction;
The underbody structure is secured to the vehicle body by a. The vehicle body lower part structure according to claim 1, wherein the first fastening portion is arranged at a position lower than the second fastening portion. The front cover portion includes a cover bottom portion having a lower surface facing the road surface,
3 . The vehicle body lower structure according to claim 2 , further comprising a cover rear wall portion provided outside the trailing arm in the vehicle width direction and standing upward from the rear end portion of the cover bottom portion. a cover side wall portion erected upward from a front end portion on the outside in the vehicle width direction of the front cover portion to the rear end portion and connected to the cover rear wall portion;
a side wall flange portion extending outward in the vehicle width direction from the cover side wall portion;
The first fastening portion is provided on the side wall flange portion,
The vehicle body lower structure according to claim 3, wherein the height of the cover rear wall portion is lower than the height of the cover side wall portion. a plurality of first ribs extending in the vehicle width direction on the upper surface or the lower surface of the undercover;
The vehicle body lower structure according to any one of claims 1 to 4, further comprising a plurality of second ribs extending in a direction orthogonal to the plurality of first ribs.

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