JP2021037784A - Vehicle body substructure - Google Patents

Abstract

To make it possible to inhibit a vibration of a propeller shaft from propagating into a vehicle compartment.SOLUTION: In a vehicle body substructure, a semicircular notch 21h is formed in a lower part of an under-floor cross member 20, and a propeller shaft is fitted in the semicircular notch 21h. A bracket 45 that supports the propeller shaft and traverses the semicircular notch 21h is disposed below the semicircular notch 21h. The under-floor cross member 20 has bracket joint parts 21d, to which the bracket 45 is joined, on both sides of the semicircular notch 21h. Inside reinforcement members 32 and 33 that extend in a vehicular vertical direction between the upper and lower parts of the under-floor cross member 20 are located at positions coinciding with the bracket joint parts 21h.SELECTED DRAWING: Figure 6

Description

The present invention relates to a vehicle body lower structure.

A propeller shaft is arranged on the lower side of the floor panel at the bottom of the vehicle body. The propeller shaft extends in the front-rear direction of the vehicle, and is, for example, a member for transmitting power from a power source located at the front to the rear wheels. For example, a four-wheel drive propeller shaft is supported by an intermediate portion of a floor panel in the vehicle front-rear direction.

As for the support structure of the propeller shaft, for example, as disclosed in Patent Document 1, a structure in which a bracket for supporting the lower portion of the propeller shaft is provided is known. Both sides of the bracket are joined to, for example, the lower surface of the floor panel.

Japanese Unexamined Patent Publication No. 2016-172474

For example, the propeller shaft of a four-wheel drive vehicle rotates to transmit power to the rear wheels, and serves as a vibration source for vibrations of the engine and transmission, vibrations of rotational fluctuations, self-excited vibrations of the propeller shaft itself, and the like. When these vibrations are propagated to the vehicle body via the support portion of the propeller shaft, they cause noise in the vehicle interior and the like.

For example, in the structure of the above example, the vibration may be propagated to the vehicle interior or the like through the joint between the bracket and the floor panel. Therefore, there is room for improvement in the above structure in suppressing the propagation of the vibration.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a vehicle body lower structure capable of suppressing propagation of vibration of a propeller shaft or the like into a vehicle interior.

The vehicle body lower structure according to the present invention for achieving the above object is arranged on both sides of the floor panel in the vehicle width direction and extends in the vehicle front-rear direction, and is arranged on the lower surface side of the floor panel and is arranged on both sides. A vehicle of the underfloor cross member having a underfloor cross member extending in the vehicle width direction so as to connect the floor side members, and a propeller shaft arranged below the floor panel and extending in the vehicle front-rear direction. Both side portions in the width direction are adjacent to the lower portion of the center pillar located in the middle portion in the vehicle front-rear direction of the floor panel. In the vehicle body lower structure, the propeller shaft can be arranged inside the lower portion of the cross member under the floor in the vehicle width direction, and a notch recessed above the vehicle is provided, and the notch is provided on the lower side of the vehicle. Is provided with brackets that support the propeller shaft and cross the notch in the vehicle width direction, and the brackets are joined to the underfloor cross members located on both sides of the notch in the vehicle width direction. The underfloor cross member is provided with a first reinforcing member extending in the vertical direction of the vehicle between the upper part and the lower part of the underfloor cross member. , The vehicle is arranged so as to overlap at least a part of the joint when viewed in the vertical direction of the vehicle.

According to the present invention, it is possible to suppress the vibration of the propeller shaft and the like from propagating into the vehicle interior.

It is a perspective view which looked at the car body lower structure which concerns on this invention from the lower part of a vehicle. It is an enlarged bottom view of the cross member under the floor of FIG. 1 and its periphery. FIG. 5 is a plan view of the floor panel of FIG. 2 as viewed from above the vehicle. It is a perspective view which shows the AA cross section of FIG. It is a regular cross-sectional view which shows the BB cross section of FIG. It is an enlarged perspective view of the bracket and the like of FIG. 2 seen from the lower side of the vehicle.

Hereinafter, an embodiment of the vehicle body lower structure according to the present invention will be described with reference to the drawings (FIGS. 1 to 6).

In the figure, the arrow Fr direction indicates the front in the vehicle front-rear direction. The "front (front end) and rear (rear end)" in the description of the embodiment correspond to the front and rear parts in the front-rear direction of the vehicle. Further, the arrows R and L indicate the right side and the left side in the vehicle width direction, respectively, and the "left and right" in the present embodiment correspond to the "left side" and the "right side" when the occupant faces the front of the vehicle. There is.

As shown in FIG. 1, the vehicle body lower structure of the present embodiment is a structure for supporting the propeller shaft 41 arranged on the lower side of the floor panel 10 at the lower part of the vehicle body. The vehicle body lower structure includes a floor panel 10, a propeller shaft 41, floor side members 2 and 3, side sills 4 and 5, an underfloor cross member 20, an above floor cross member 25 (FIG. 3), and a bracket 45. And have.

The floor panel 10 is a panel member arranged in the lower part of the vehicle body and constituting the floor portion of the vehicle interior, and as shown in FIGS. 2 to 4, it has a plate shape extending from the vicinity of the rear portion of the left and right front wheels (not shown) to the rear portion of the vehicle. It is a member of. The vehicle width direction dimension of the floor panel 10 substantially corresponds to the vehicle width direction dimension of the vehicle body. The floor panel 10 of the present embodiment has a right side panel 12 and a left side panel 13. The right side panel 12 and the left side panel 13 are arranged so as to be spaced apart from each other in the vehicle width direction. That is, an opening extending in the front-rear direction of the vehicle is formed in the central portion of the floor panel 10 in the vehicle width direction.

A floor tunnel 15 is provided in the opening. The floor tunnel 15 extends in the front-rear direction of the vehicle so as to close the opening. That is, in the present embodiment, the floor tunnel 15 is composed of a member different from the floor panel 10.

As shown in FIGS. 2 to 6, the floor tunnel 15 has a top surface portion 15a, a right wall portion 15b, a left wall portion 15c, a right flange portion 15d, and a left flange portion 15e. The top surface portion 15a is arranged on the upper side of the vehicle with respect to the right side panel 12 and the left side panel 13, has a top surface facing the upper part of the vehicle, and extends in the front-rear direction of the vehicle.

The right wall portion 15b projects downward from the right side portion of the top surface portion 15a in the vehicle width direction and extends in the vehicle front-rear direction. The left wall portion 15c projects downward from the left side portion of the top surface portion 15a in the vehicle width direction and extends in the vehicle front-rear direction. The right flange portion 15d projects to the right in the vehicle width direction from the lower end of the right wall portion 15b and extends in the vehicle front-rear direction. The left flange portion 15e protrudes to the left in the vehicle width direction from the lower end of the left wall portion 15c and extends in the vehicle front-rear direction.

As shown in FIGS. 4 and 5, the floor tunnel 15 is opened downward by the top surface portion 15a, the right wall portion 15b, the left wall portion 15c, the right flange portion 15d, and the left flange portion 15e in the front-rear direction of the vehicle. It forms a hat-shaped cross-sectional shape. Further, the upper surface of the right flange portion 15d is joined to the inner edge portion in the vehicle width direction of the lower surface of the right panel 12, and the mirror surface of the left flange portion 15e is joined to the inner edge portion in the vehicle width direction of the lower surface of the left panel 13. Has been done.

Next, the floor side members 2 and 3 and the side sills 4 and 5 will be described. As shown in FIGS. 1 and 2, the floor side members 2 and 3 have a floor side member 2 on the right side and a floor side member 3 on the left side. The floor side members 2 and 3 on both sides are arranged so as to form a pair on the left and right at intervals in the vehicle width direction. Further, the side sills 4 and 5 are members extending in the front-rear direction of the vehicle, and are provided on the outside of the floor side members 2 and 3 on both sides in the vehicle width direction.

The floor side member 2 on the right side is a member arranged on the lower surface of the floor panel 10 on the right outer side in the vehicle width direction, and has a straight line portion 2a and an inclined portion 2b. The straight portion 2a extends in the front-rear direction of the vehicle, and is joined to the right outer edge of the lower surface of the floor panel 10 in the vehicle width direction by spot welding or the like. Further, the outer portion of the straight portion 2a in the vehicle width direction is also joined to the side sill 4 on the right side. The inclined portion 2b is joined to the lower surface of the floor panel 10, and extends inwardly in the vehicle width direction from the front portion of the straight portion 2a toward the front of the vehicle.

As shown in FIG. 2, the floor side member 3 on the left side is a member arranged on the left outer side in the vehicle width direction on the lower surface of the floor panel 10, and is inclined with the straight portion 3a like the floor side member 2 on the right side. It has a part 3b. The straight portion 3a extends in the front-rear direction of the vehicle, is joined to the left outer edge of the lower surface of the floor panel 10 in the vehicle width direction, and is further joined to the left side sill 5. The inclined portion 3b is joined to the lower surface thereof, and extends inwardly inward in the vehicle width direction from the front portion of the straight portion 3a toward the front of the vehicle.

Next, the underfloor cross member 20 will be described. As shown in FIGS. 2, 4 and 5, the underfloor cross member 20 is a member extending in the vehicle width direction so as to connect the straight portions 2a and 3a of the left and right floor side members 2 and 3. The underfloor cross member 20 has a central member 21, a right outer member 22, and a left outer member 23.

As shown in FIGS. 4 and 5, the central member 21 extends in the vehicle width direction so as to bridge the opening of the floor tunnel 15. The central member 21 has a front wall portion 21a, a rear wall portion 21b, a lower surface portion 21c, a front flange portion 21e, and a rear flange portion 21f. The front wall portion 21a has a wall surface facing the front of the vehicle and extends in the vehicle width direction. At the upper end of the front wall portion 21a, the central portion in the vehicle width direction projects upward from the outer portion to form a convex shape as a whole. The lower end of the front wall portion 21a will be described later.

As shown in FIG. 2, the front flange portion 21e projects from the upper end of the front wall portion 21a to the front of the vehicle and extends in the vehicle width direction. Further, the front flange portion 21e has a convex shape as a whole when viewed in the front-rear direction of the vehicle so as to correspond to the shape of the upper end of the front wall portion 21a. The central portion and the left and right outer portions of the front flange portion 21e extend in the vehicle width direction, and the vertical wall portion connecting the central end and the outer end of the front flange portion 21e extends in the vehicle vertical direction.

The central portion of the front flange portion 21e in the vehicle width direction is joined to the lower surface (back surface) of the top surface portion 15a of the floor tunnel 15. Further, the vertical wall portions extending downward from both sides of the central portion are joined to the right wall portion 15b and the left wall portion 15c of the floor tunnel 15. The right outer portion of the front flange portion 21e is joined to the lower surface of the right flange portion 15d of the floor tunnel 15 and the lower surface of the right panel 12, and the left outer portion of the front flange portion 21e is the left flange portion 15e of the floor tunnel 15. It is joined to the lower surface of the tunnel and the lower surface of the left panel 13.

The rear wall portion 21b has a wall surface facing the rear of the vehicle and extends in the vehicle width direction. Similar to the front wall portion 21a, the upper end of the rear wall portion 21b has a central portion in the vehicle width direction protruding upward from the outer portion to form a convex shape as a whole. The lower end of the rear wall portion 21b will be described later.

The rear flange portion 21f projects from the upper end of the rear wall portion 21b to the rear of the vehicle and extends in the vehicle width direction, and like the front flange portion 21e, is convex as a whole corresponding to the shape of the upper end of the rear wall portion 21b. It has a shape. Like the front flange portion 21e, the rear flange portion 21f is joined to the lower surface of the top surface portion 15a of the floor tunnel 15, the right wall portion 15b and the left wall portion 15c, and the lower surface of the right panel 12 and the lower surface of the left panel 13. Has been done.

As shown in FIGS. 5 and 6, the lower surface portion 21c connects the lower end of the front wall portion 21a and the lower end of the rear wall portion 21b and extends in the vehicle width direction. Further, as shown in FIGS. 5 and 6, the lower surface portion 21c, the front wall portion 21a, and the rear wall portion 21b of the central member 21 have a semicircular shape cut out in a substantially semicircular shape so as to be recessed above the vehicle. A notch 21h is provided. The semicircular notch 21h extends in the front-rear direction of the vehicle so as to communicate from the front wall portion 21a to the rear wall portion 21b. Bracket joints (joints) 21d to which the brackets 45, which will be described later, are joined, are provided on the left and right edges of the semicircular notch 21h.

Next, the right outer member 22 of the underfloor cross member 20 will be described. As shown in FIGS. 2 and 4 to 6, the right outer member 22 is joined to the right side portion of the central member 21 in the vehicle width direction and extends in the vehicle width direction. The outer portion of the right outer member 22 in the vehicle width direction is joined to the straight portion 2a of the floor side member 2 on the right side. The right outer member 22 has a front wall portion 22a, a rear wall portion 22b, a lower surface portion 22c, a front flange portion 22e, and a rear flange portion 22f, similarly to the central member 21.

The front wall portion 22a of the right outer member 22 has a wall surface facing the front of the vehicle and extends in the vehicle width direction. The inner portion of the front wall portion 22a of the right outer member 22 in the vehicle width direction is joined to the outer portion of the front wall portion 21a of the central member 21 in the vehicle width direction so as to be continuous. The outer portion of the front wall portion 22a of the right outer member 22 in the vehicle width direction is joined to the straight portion 2a of the floor side member 2 on the right side. The rear wall portion 22b of the right outer member 22 is also configured in the same manner as the front wall portion 22a.

The lower surface portion 22c of the right outer member 22 connects the lower end of the front wall portion 22a and the lower end of the rear wall portion 22b, and extends in the vehicle width direction. The inner portion of the lower surface portion 22c of the right outer member 22 in the vehicle width direction is joined to the outer portion of the lower surface portion 21c of the central member 21 in the vehicle width direction so as to be continuous. The outer side portion of the lower surface portion 22c of the right outer member 22 in the vehicle width direction is joined to the straight portion 2a.

The front flange portion 22e of the right outer member 22 projects forward from the upper end of the front wall portion 22a and extends in the vehicle width direction. The front flange portion 22e of the right outer member 22 is joined to the lower surface of the right panel 12. The inner portion of the front flange portion 22e of the right outer member 22 in the vehicle width direction is joined in a state of being sandwiched between the outer portion of the front flange portion 21e of the central member 21 in the vehicle width direction and the right panel 12. The outer portion of the front flange portion 22e of the right outer member 22 in the vehicle width direction is joined to the straight portion 2a of the floor side member 2 on the right side.

The rear flange portion 22f of the right outer member 22 projects rearward from the upper end of the rear wall portion 22b and extends in the vehicle width direction. The rear flange portion 22f of the right outer member 22 is joined to the rear flange portion 21f of the central member 21, the lower surface of the right panel 12, and the straight portion 2a, similarly to the front flange portion 22e.

Next, the left outer member 23 is joined to the left side portion of the central member 21 in the vehicle width direction and extends in the vehicle width direction. The outer portion of the left outer member 23 in the vehicle width direction is joined to the straight portion 3a of the left floor side member 3. Like the right outer member 22, the left outer member 23 has a front wall portion 23a, a rear wall portion 23b, a lower surface portion 23c, a front flange portion 23e, and a rear flange portion 23f. It is configured in the same manner as the right outer member 22.

Subsequently, the propeller shaft 41 and the bracket 45 will be described. The propeller shaft 41 is a member extending in the front-rear direction of the vehicle, and is arranged on the lower side of the vehicle in the floor tunnel 15 as shown in FIG. Further, it is arranged inside the semicircular notch 21h of the cross member 20 under the floor. In FIGS. 2 to 6, the propeller shaft 41 is not shown.

As shown in FIGS. 5 and 6, the bracket 45 has a support portion 45a, a right flange portion 45b, and a left flange portion 45c. The support portion 45a is a substantially semicircular portion that is convex downward in the vehicle when viewed in the front-rear direction of the vehicle, and supports the propeller shaft 41 from the lower side. The right flange portion 45b projects outward in the vehicle width direction from the right end of the support portion 45a, and is joined to the right bracket joint portion 21d provided on the lower surface portion 21c of the central member 21. Like the right flange portion 45b, the left flange portion 45c projects outward from the left end of the support portion 45a in the vehicle width direction and is joined to the bracket joint portion 21d on the left side of the central member 21.

As shown in FIGS. 4 to 6, the underfloor cross member 20 is provided with two inner reinforcing members (first reinforcing members) 32 and 33 arranged at intervals in the vehicle width direction (left and right). ing. The inner reinforcing members 32 and 33 are members extending in the vertical direction of the vehicle between the upper part and the lower part of the underfloor cross member 20, and are provided on the left and right sides of the semicircular notch 21h of the central member 21.

The main body of the inner reinforcing member 32 on the right side has a hollow substantially rectangular parallelepiped shape in which the inside in the vehicle width direction is open, and at a position corresponding to the bracket joint portion 21d on the right side, the lower surface portion 21c of the central member 21 and the floor tunnel 15 It extends in the vertical direction of the vehicle so as to connect the top surface portion 15a of the vehicle, and extends in the front-rear direction of the vehicle between the front wall portion 21a and the rear wall portion 21b of the central member 21. The lower end surface of the main body of the inner reinforcing member 32 on the right side is joined to the upper surface side of the lower surface portion 21c of the central member 21. In this example, the main body of the inner reinforcing member 32 on the right side, the bracket joint portion 21d on the right side, and the flange portion 45b on the right side of the bracket 45 are joined in three layers.

As shown in FIG. 6, a front flange 32b projecting to the front of the vehicle is provided at the front end of the upper part of the main body of the inner reinforcing member 32 on the right side. Further, a rear flange 32c projecting to the rear of the vehicle is provided at the rear end of the upper part of the main body. Further, an outer flange 32d projecting outward in the vehicle width direction is provided on the outer side of the upper part of the main body in the vehicle width direction.

The front flange 32b of the inner reinforcing member 32 on the right side is joined by the front flange portion 21e of the central member 21 and the top surface portion 15a of the floor tunnel 15, that is, in a three-layered state. Similarly, the rear flange 32c of the inner reinforcing member 32 on the right side is joined by the rear flange portion 21f of the central member 21 and the top surface portion 15a of the floor tunnel 15 in a three-layered state. Further, the outer flange 32d of the inner reinforcing member 32 on the right side is joined to the top surface portion 15a.

The main body of the inner reinforcing member 33 on the left side has a hollow substantially rectangular parallelepiped shape in which the inside in the vehicle width direction is open, and at a position corresponding to the bracket joint portion 21d on the left side, the lower surface portion 21c of the central member 21 and the floor tunnel 15 It extends in the vertical direction of the vehicle so as to connect the left side flange portion 15e of the vehicle, and extends in the front-rear direction of the vehicle so as to connect the front wall portion 21a and the rear wall portion 21b of the central member 21. The lower end surface of the main body of the inner reinforcing member 33 on the left side is joined to the left flange portion 45c of the bracket 45 in a three-layered state via the bracket joining portion 21d on the left side of the central member 21.

The main body of the inner reinforcing member 33 on the left side is provided with a front flange 33b and a rear flange 33c, similarly to the inner reinforcing member 32 on the right side. Further, although the description by illustration is omitted, an outer flange may be provided at the left outer end of the main body of the inner reinforcing member 33 on the left side in the vehicle width direction. The front flange 33b of the left inner reinforcing member 33 is joined in a three-layered state sandwiched between the front flange portion 21e of the central member 21 and the left flange portion 15e of the floor tunnel 15. Similarly, the rear flange 33c of the inner reinforcing member 33 on the left side is joined by the rear flange portion 21f of the central member 21 and the left flange portion 15e of the floor tunnel 15 in a three-layered state. Further, when the outer flange of the inner reinforcing member 33 on the left side is provided, it may be joined to the left flange portion 15e of the floor tunnel 15.

In the present embodiment, in order to support the propeller shaft 41, a bracket structure is not simply provided, but a cross member 20 under the floor is provided, and a support structure is provided in the central portion thereof. Further, inner reinforcing members 32 and 33 are provided corresponding to the mounting portion of the bracket 45. As a result, by setting the center of the propeller shaft 41 and the lower surface portion 21c (lower surface) of the underfloor cross member 20 to the same height or higher, the vibration of the propeller shaft 41 is caused more than that of the underfloor cross member 20. It can be received efficiently.

Further, since the inner reinforcing members 32 and 33 are provided at the positions corresponding to the bracket joints 21d, the entire underfloor cross member 20 can receive the load from the propeller shaft 41, so that the support effect is increased. .. In the present embodiment, the propeller shaft 41 is arranged so as to be shifted from the center of the floor tunnel 15 in the vehicle width direction, but the present invention is not limited to this, and the propeller shaft 41 may be arranged at the center.

As shown in FIGS. 3 to 5, the above-floor cross member 25 is a member extending in the vehicle width direction, is joined to the upper surface of the floor panel 10, and is arranged at a position corresponding to the under-floor cross member 20. .. That is, the floor panel 10 is sandwiched between the lower floor cross member 20 and the upper floor cross member 25. As a result, the rigidity of the floor panel 10 is ensured. Further, the outer portion of the cross member 25 on the floor in the vehicle width direction is provided at a position corresponding to the floor side members 2 and 3.

The floor cross member 25 has an upper surface portion 25d, a front wall portion 25a, a rear wall portion 25b, a front flange portion 25e, and a rear flange portion 25f. The upper surface portion 25d is arranged above the vehicle on the top surface portion 15a of the floor tunnel 15 at intervals, and extends in the vehicle width direction so as to straddle the top surface portion 15a. The front wall portion 25a has a wall surface facing the front of the vehicle, and a recess is provided in the central portion in the vehicle width direction so as to correspond to the shape of the floor tunnel 15. The rear wall portion 25b has a wall surface facing the rear of the vehicle, and like the front wall portion 25a, a recess is provided so as to correspond to the shape of the floor tunnel 15.

The front flange portion 25e of the cross member 25 on the floor projects forward from the lower end of the front wall portion 25a to the front of the vehicle and extends in the vehicle width direction. The rear flange portion 25f projects rearward from the lower end of the rear wall portion 25b and extends in the vehicle width direction. The front flange portion 25e and the rear flange portion 25f correspond to the shape of the floor tunnel 15 like the front wall portion 25a and the rear wall portion 25b, and the right side panel 12 and the left side panel 13 of the floor panel 10 and the floor tunnel 15 It is joined to the top surface portion 15a of the above.

As shown in FIGS. 4 and 5, the cross member 25 on the floor is provided with two upper reinforcing members (second reinforcing members) 34 and 35 arranged at intervals in the vehicle width direction. The upper reinforcing members 34 and 35 are members extending in the vertical direction of the vehicle between the upper portion and the lower portion of the cross member 25 on the floor, and are adjacent to the outer side of the inner reinforcing members 32 and 33 in the vehicle width direction.

In the present embodiment, the upper reinforcing member 34 on the right side is adjacent to the inner reinforcing member 32 on the right side in the vertical direction of the vehicle and is arranged so as to be offset to the right outer side in the vehicle width direction, and the upper reinforcing member 35 on the left side is on the left side. It is adjacent to the inner reinforcing member 33 in the vehicle vertical direction and is arranged so as to be offset to the left outer side in the vehicle width direction. That is, the upper reinforcing member 34 on the right side is arranged diagonally above the right side of the inner reinforcing member 32 on the right side, and the upper reinforcing member 35 on the left side is arranged diagonally above the left side of the inner reinforcing member 33 on the left side.

The main body of the upper reinforcing member 34 on the right side has a hollow substantially rectangular parallelepiped shape, extends in the vertical direction of the vehicle so as to connect between the upper surface portion 25d of the cross member 25 on the floor and the top surface portion 15a of the floor tunnel 15. , The front wall portion 25a and the rear wall portion 25b of the cross member 25 on the floor extend in the front-rear direction of the vehicle.

The upper end surface of the main body of the upper reinforcing member 34 on the right side is joined to the upper surface portion 25d of the cross member 25 on the floor. The lower end surface of the main body of the upper reinforcing member 34 on the right side is joined to the right end of the top surface portion 15a of the floor tunnel 15. The lower end surface of the main body is joined at a position corresponding to the outer flange 32d of the inner reinforcing member 32 on the right side. That is, the lower end surface of the main body of the upper reinforcing member 34 on the right side, the top surface portion 15a, and the outer flange 32d of the inner reinforcing member 32 on the right side are joined in three layers. The lower end surface of the main body may be joined at a position slightly adjacent to the right side of the outer flange 32d of the inner reinforcing member 32 on the right side. With this configuration, the continuity of rigidity is ensured.

The main body of the upper reinforcing member 35 on the left side has a hollow substantially rectangular parallelepiped shape, and extends in the vertical direction of the vehicle so as to connect the upper surface portion 25d of the cross member 25 on the floor and the left flange portion 15e of the floor tunnel 15. Moreover, it extends in the front-rear direction of the vehicle between the front wall portion 25a and the rear wall portion 25b of the cross member 25 on the floor.

The upper end surface of the main body of the upper reinforcing member 35 on the left side is joined to the upper surface portion 25d of the cross member 25 on the floor. The lower end surface of the main body of the upper reinforcing member 35 on the left side is joined to the left panel 13. In this example, the lower end surface of the main body of the upper reinforcing member 35 on the left side is joined to the left flange portion 15e of the floor tunnel 15 in three layers via the left panel 13. Further, the lower end of the main body is joined at a position slightly adjacent to the left side with respect to the outer flange of the inner reinforcing member 33 on the left side. With this configuration, the continuity of rigidity is ensured.

As shown in FIGS. 3 to 5, a seat bracket 47 is provided on the upper surface portion 25d of the cross member 25 on the floor. High rigidity is required for the seat mounting portion provided on the floor panel 10. Therefore, the seat bracket 47 provided on the cross member 25 on the floor is ensured to have high rigidity. A seat rail or the like (not shown) is fixed to the seat bracket 47. In the present embodiment, the seat bracket 47 is arranged substantially directly above the upper reinforcing members 34 and 35.

With this configuration, the load received by the inner reinforcing members 32 and 33 can be received by the upper reinforcing members 34 and 35. Further, the upper reinforcing members 34 and 35 can form a closed cross section on the cross member 25 on the floor, and the load can be transmitted to the upper surface portion 25d of the cross member 25 on the floor.

Further, since the seat bracket 47 is provided directly above the upper reinforcing members 34 and 35, the load received by the upper reinforcing members 34 and 35 can be further transmitted to the seat bracket 47. Further, the load received by the seat bracket 47 can be transmitted to the seat rail or the like. That is, the rigidity of the seat bracket 47 can be used with respect to the load, and the rigidity of the seat rail or the like can also be used. With this configuration, it is possible to improve the support rigidity of the propeller shaft 41 by utilizing the rigidity of the seat bracket 47 and its peripheral members, and the upper reinforcing members 34, 35, the seat bracket 47, the seat rail, etc. The load can be efficiently distributed to the members of the above.

In the present embodiment, as shown in FIGS. 4 to 6, the underfloor cross member 20 has two outer reinforcing members (third reinforcing members) 36 arranged at intervals in the vehicle width direction (left and right). , 37 are provided. The outer reinforcing member 36 on the right side is arranged on the right outer side in the vehicle width direction with respect to the inner reinforcing member 32 on the right side, and the outer reinforcing member 37 on the left side is arranged in the vehicle width direction with respect to the inner reinforcing member 33 on the left side. It is located on the left outer side. Further, the outer reinforcing member 36 on the right side is provided at a position where the central member 21 and the outer right outer member 22 are joined, and the outer reinforcing member 37 on the left side is joined to the central member 21 and the left outer member 23. It is provided at the position where it is.

The main body of the outer reinforcing member 36 on the right side has a hollow substantially rectangular parallelepiped shape, extends in the vertical direction of the vehicle so as to connect the right panel 12, the joint portion between the central member 21 and the right outer member 22, and is on the right. It extends in the front-rear direction of the vehicle so as to connect the front wall portion 22a and the rear wall portion 22b at the inner end of the outer member 22. The lower end surface of the main body of the outer reinforcing member 36 on the right side is joined to the upper surface side of the lower surface portion 22c of the right outer member 22. In this example, the lower end surface of the main body of the outer reinforcing member 36 on the right side, the lower surface portion 22c of the right outer member 22, and the lower surface portion 21c of the central member 21 are joined in three layers. Further, the upper end surface of the main body is joined to the right panel 12.

At least one of the front portion and the rear portion of the main body of the outer reinforcing member 36 on the right side may be joined to the corresponding wall portions (front wall portion 22a and rear wall portion 22b) of the right outer member 22. Further, the main body of the outer reinforcing member 37 on the left side has a hollow substantially rectangular parallelepiped shape, extends in the vertical direction of the vehicle so as to connect the left side panel 13 and the joint portion between the central member 21 and the left outer member 23, and extends in the vertical direction of the vehicle. It extends in the front-rear direction of the vehicle so as to connect the front wall portion 23a and the rear wall portion 23b at the inner end of the left outer member 23. The lower end surface of the main body of the left outer reinforcing member 37 is joined to the lower surface portion 23c of the left outer member 23. In this example, the lower end surface of the main body of the outer reinforcing member 37 on the left side, the lower surface portion 23c of the left outer member 23, and the lower surface portion 21c of the central member 21 are joined in three layers. The upper end surface of the main body is joined to the left panel 13.

In the present embodiment, since the underfloor cross member 20 is composed of three members, for example, the thickness of the central member 21 in which the load is easily concentrated can be increased to increase the rigidity. As a result, it is possible to secure the rigidity of the required portion while reducing the weight of the right outer member 22 and the left outer member 23. Further, since the outer reinforcing members 36 and 37 are provided at the joint portion between the outer members 22 and 23 and the central member 21, the torsional rigidity of the underfloor cross member 20 is improved. As a result, it is possible to prevent the support portion 45a of the propeller shaft 41 from vibrating in the front-rear direction of the vehicle due to the twisting of the underfloor cross member 20.

Further, in the present embodiment, the left and right outer members 22 and 23 of the underfloor cross member 20 are the floor side members 2 and 23 located at the roots of the left and right center pillars 7, as shown in FIGS. 1, 4 and 5. It is joined to the straight portions 2a and 3a of 3.

The floor side members 2 and 3 are high-rigidity members that form the main skeleton of the vehicle body side. Therefore, the rigidity of the underfloor cross member 20 is further improved by joining the right outer member 22 and the left outer member 23 of the underfloor cross member 20 to the left and right floor side members 2 and 3. In particular, the base of the center pillar 7 is the key to the rigidity of the vehicle body because the center pillar 7 supports the roof. By joining the lower cross member to the base of the center pillar 7, the lower cross member 20 is effectively supported, and the propeller shaft 41 can be supported via the central member 21.

In the present embodiment, the floor side members 2 and 3 of the floor cross member 25 are joined to the floor side members 2 and 3 via the floor panel 10, and the same effect can be obtained with respect to the rigidity of the floor cross member 25.

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

For example, in the present embodiment, the ends of the left and right outer members of the underfloor cross member 20 are joined to the floor side members 2 and 3, but the present invention is not limited to this. For example, the floor side members 2 and 3 may be joined to the side sills 4 and 5 located outside in the vehicle width direction.

2 Right floor side member 2a Straight part 2b Inclined part 3 Left floor side member 3a Straight part 3b Inclined part 4 Right side sill 5 Left side sill 7 Center pillar 10 Floor panel 12 Right panel 13 Left panel 15 Floor tunnel 15a Top surface 15b Right wall part 15c Left wall part 15d Right side flange part 15e Left side flange part 20 Underfloor cross member 21 Central member 21a Front wall part 21b Rear wall part 21c Bottom part 21d Bracket joint part 21e Front side flange part 21f Rear side flange part 21h Half Circular notch 22 Right outer member 22a Front wall 22b Rear wall 22c Lower surface 22e Front flange 22f Rear flange 23 Left outer member 23a Front wall 23b Rear wall 23c Lower surface 23e Front flange 23f Rear side Flange 25 Floor cross member 25a Front wall 25b Rear wall 25d Top surface 25e Front flange 25f Rear flange 32 Inner reinforcing member on the right side (first reinforcing member)
32b Front flange 32c Rear flange 32d Outer flange 33 Left inner reinforcing member (first reinforcing member)
33b Front flange 33c Rear flange 34 Upper right side reinforcing member (second reinforcing member)
35 Left upper reinforcing member (second reinforcing member)
36 Outer reinforcement member on the right side (third reinforcement member)
37 Left outer reinforcing member (third reinforcing member)
41 Propeller shaft 45 Bracket 45a Support 45b Right flange 45c Left flange 47 Seat bracket

Claims (4)

Floor side members arranged on both sides of the floor panel in the vehicle width direction and extending in the vehicle front-rear direction, and under the floor arranged on the lower surface side of the floor panel and extending in the vehicle width direction so as to connect the floor side members on both sides. It has a cross member and a propeller shaft that is arranged on the lower side of the floor panel and extends in the front-rear direction of the vehicle.
In the vehicle body lower structure, both sides of the underfloor cross member in the vehicle width direction are adjacent to the lower part of the center pillar located in the middle portion of the floor panel in the vehicle front-rear direction.
The propeller shaft can be arranged inside the lower part of the cross member under the floor in the vehicle width direction, and a notch recessed above the vehicle is provided.
On the lower side of the notch on the vehicle, a bracket that supports the propeller shaft and crosses the notch in the vehicle width direction is provided.
The underfloor cross members located on both sides of the notch in the vehicle width direction are provided with joints to which the brackets are joined.
The underfloor cross member is provided with a first reinforcing member extending in the vehicle vertical direction between the upper portion and the lower portion of the underfloor cross member, and the first reinforcing member is the vehicle vertical view. A vehicle body lower structure characterized in that it is arranged so as to overlap at least a part of the joint. On the upper surface of the floor panel, an on-floor cross member extending in the vehicle width direction is provided at a position corresponding to the under-floor cross member.
A second reinforcing member extending in the vehicle vertical direction is provided between the upper portion and the lower portion of the floor cross member in the vehicle width direction intermediate portion of the floor cross member, and the second reinforcing member and the second reinforcing member are provided. The reinforcing members of 1 are arranged adjacent to each other in the vertical direction of the vehicle.
The vehicle body lower structure according to claim 1, wherein a seat bracket is provided on the upper portion of the cross member on the floor corresponding to the second reinforcing member. The underfloor cross member has a central member extending in the vehicle width direction and outer members extending outward in the vehicle width direction from outer portions in the vehicle width direction on both sides of the central member.
A third reinforcing member extending in the vertical direction of the vehicle is provided between the upper portion and the lower portion of the underfloor cross member at a position where the central member and the outer member are joined. The vehicle body lower structure according to claim 1 or 2. The vehicle width direction outer portion of the underfloor cross member is joined to the floor side member located at the base of the center pillar or a side sill arranged outside the floor side member in the vehicle width direction and extending in the vehicle front-rear direction. The vehicle body lower structure according to any one of claims 1 to 3, wherein the vehicle body lower structure is characterized by the above.