JP2023097563A - Vehicle body lower part structure - Google Patents

Abstract

To transmit a lateral collision load, which is input offset in a vehicle fore and aft direction, to a floor cross member smoothly.SOLUTION: A vehicle body lower part structure includes: a floor cross member 16 which connects a side sill 12 disposed at the outer side in a vehicle width direction with a floor tunnel 14 disposed at a center of a vehicle body and is disposed so as to be sandwiched between seat brackets 22a, 22b in a vehicle fore and aft direction. An outer end as seen in the vehicle width direction of the floor cross member 16 includes a widening part 30 which widens in the vehicle fore and aft direction. Beads 36 extending along a front wall 28b and a rear wall 28c are provided on an upper surface of an upper wall 28a of the floor cross member 16.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to, for example, a vehicle body lower structure of an automobile or the like.

For example, Patent Document 1 discloses a vehicle body lower structure that exhibits an H-shaped structure when viewed from above, and in which one floor cross member is arranged along the vehicle width direction between a side sill and a floor tunnel. there is

A seat attachment portion is provided on each of the floor cross members in the vehicle front-rear direction.

Japanese Patent No. 6311679

Incidentally, the side impact load input from the side sill may be input in a state offset in the longitudinal direction of the vehicle with respect to the floor cross member. In the H-shaped structure disclosed in Patent Document 1, the deformation of the sub-tunnel arranged between the side sill and the outer end of the floor cross member causes the offset input side impact load to be applied to the floor cross member. It may be difficult to transmit smoothly.

As a result, in the H-shaped structure disclosed in Patent Document 1, when a side impact load that is offset in the longitudinal direction of the vehicle is input, there is a risk that the amount of deformation in the interior due to this offset side impact load will increase.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle body lower structure capable of smoothly transmitting a side impact load that is offset in the vehicle longitudinal direction to a floor cross member. for the purpose.

Another object of the present invention is to provide a vehicle body lower structure that can reduce the weight of the vehicle body lower part.

In order to achieve the above object, the present invention connects a side sill arranged on the outside in the vehicle width direction and a floor tunnel arranged in the center of the vehicle body, and is arranged so as to be sandwiched between seat brackets in the vehicle front-rear direction. A vehicle body lower structure having a floor cross member is characterized in that a vehicle width direction outer end portion of the floor cross member is provided with a widened portion that widens in the vehicle front-rear direction.

According to the present invention, it is possible to obtain a vehicle body lower structure capable of smoothly transmitting a side impact load that is offset in the longitudinal direction of the vehicle to the floor cross member.

Further, in the present invention, it is possible to obtain a vehicle body lower part structure capable of achieving weight reduction of the vehicle body lower part weight.

1 is a top plan view of a vehicle front portion to which a vehicle body lower structure according to an embodiment of the present invention is applied; FIG. FIG. 2 is a longitudinal cross-sectional view taken along line II-II of FIG. 1; FIG. 2 is a partially transparent plan view of the front portion of the vehicle shown in FIG. 1; FIG. 2 is a partially transparent bottom view of the front portion of the vehicle shown in FIG. 1 as viewed from the bottom side; FIG. 5 is an operation explanatory diagram showing a state in which a side impact load offset in the vehicle longitudinal direction is transmitted; FIG. 4 is an end view showing the inner floor frame and the outer floor frame; FIG. 5 is a schematic diagram showing a modification of the widened portion of the floor cross member; FIG. 10 is a schematic diagram showing another modification of the widened portion of the floor cross member; FIG. 4 is a partially broken perspective view showing a state in which the vehicle width direction inner end portion of the floor cross member is coupled to the floor tunnel; FIG. 4 is a partially see-through cross-sectional view showing a reinforcing member arranged within the cross-section of the side sill;

Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In each figure, "front and back" indicates the longitudinal direction of the vehicle, "left and right" indicates the width direction of the vehicle (horizontal direction), and "up and down" indicates the vertical direction of the vehicle (vertical direction).

As shown in FIG. 1, a vehicle 10 to which a vehicle body lower structure according to an embodiment of the present invention is applied includes side sills 12 arranged on the outside in the vehicle width direction, floor tunnels 14 arranged in the center of the vehicle body, and The single floor cross member 16 is arranged along the width direction and connects the side sill 12 and the floor tunnel 14, and the floor panel 18 is arranged between the side sill 12 and the floor tunnel 14. there is In FIG. 1, only the left side portion of the vehicle body is shown in plan view, and the right side portion of the vehicle body, which is arranged line-symmetrically with the left side portion of the vehicle body, is omitted.

A vehicle width direction inner end portion 20 of the floor cross member 16, which is adjacent to the floor tunnel 14, is arranged so as to be sandwiched in the vehicle longitudinal direction by a pair of first seat brackets 22a and 22b. A vehicle width direction outer end portion 24 of the floor cross member 16, which is adjacent to the side sill 12, is arranged so as to be sandwiched in the vehicle front-rear direction by a pair of second seat brackets 26a and 26b.

The floor cross member 16 has a substantially hat-shaped cross-section perpendicular to its axis (see FIG. 2). As shown in FIG. 2, the floor cross member 16 includes an upper wall 28a arranged on the upper surface, and an upper wall 28a that bends downward from the front end of the vehicle and extends along the vehicle width direction. A front wall 28b that extends, a rear wall 28c that bends downward from the vehicle rear end of the upper wall 28a and extends along the vehicle width direction, and a lower end of the front wall 28b that bends toward the vehicle front side. and a rear flange portion 28e that bends toward the vehicle rear side from the lower end of the rear wall 28c. The front flange portion 28d and the rear flange portion 28e are joined and fixed to the upper surface of the floor panel 18, for example, by spot welding or the like.

Further, the vehicle width direction outside end portion 24 of the floor cross member 16 is provided with a widened portion 30 that widens in the vehicle front-rear direction toward the end portion on the side sill 12 side (see the broken line portion in FIG. 1). The widened portion 30 includes both a front widened portion 32a that widens toward the front of the vehicle and a rear widened portion 32b that widens toward the rear of the vehicle at the outer end portion 24 of the floor cross member 16 in the vehicle width direction. ing.

In the present embodiment, the widened portion 30 includes both the front widened portion 32a and the rear widened portion 32b, but the widened portion 30 is not limited to this. For example, as shown in the modified example of FIG. 7, the vehicle width direction outer end portion 24 of the floor cross member 16a has only a front widened portion 32a that widens toward the vehicle front side, and the vehicle rear side is widened. It may be configured with a flat portion 34 that is continuous with other portions to be slid. Further, as shown in a floor cross member 16b according to another modified example of FIG. 8, only a rear side widening portion 32b that widens toward the rear side of the vehicle is provided, and the width of the front side of the vehicle is not widened and other portions are provided. It may be composed of a flat portion 34 continuous with the . In this manner, at least one of the widened portions 30 may be widened in the vehicle front-rear direction.

As shown in FIGS. 1 and 2, the upper surface of the upper wall 28a of the floor cross member 16 is provided with a bead 36 that bulges upward and extends in the vehicle width direction. The bead 36 is composed of a front bead 38a extending along the front wall 28b and a rear bead 38b extending along the rear wall 28c. The front side bead 38a and the rear side bead 38b are not limited to the widened portion 30 located on the outer side in the vehicle width direction, but also the positions of the first seat brackets 22a and 22b (floor tunnel) located on the inner side of the widened portion 30 in the vehicle width direction. 14).

Between the front bead 38a and the rear bead 38b, there is provided a recess 40 that is recessed toward the floor panel 18 (downward). The recessed portion 40 extends along the longitudinal direction (vehicle width direction) of the floor cross member 16 and is configured such that the width dimension of the widened portion 30 in the vehicle front-rear direction increases. Therefore, the width dimension in the vehicle front-rear direction of the recess 40 closest to the side sill 12 is the maximum. In the intermediate portion of the recess 40, for example, a plurality of circular recesses 42a having inner diameters of large, medium and small and a single elliptical recess 42b are provided. The width dimension of the recess 40 provided in the widened portion 30, except for the recess 40, the plurality of circular recesses 42a, and the elliptical recess 42b, is substantially constant. In this embodiment, as an example, the recess 40 is provided between the front bead 38a and the rear bead 38b. You may provide the convex part which bulges out.

A vehicle width direction inner end portion 20 of the floor cross member 16 is connected to the floor tunnel 14 . That is, as shown in FIG. 9, the vehicle width direction inner end portion 20 of the floor cross member 16 has an upper flange 44a joined to the upper surface of the floor tunnel 14 and a front flange 44b joined to the side surface of the floor tunnel 14. and a rear flange 44c.

First seat brackets 22a and 22b connected to the floor tunnel 14 are arranged in the longitudinal direction of the vehicle at the end portion of the floor cross member 16 on the side of the floor tunnel 14 (the portion near the inner end portion 20 in the vehicle width direction). ing. A recessed portion 40 provided on the upper surface of the floor cross member 16 extends to a position overlapping the first seat brackets 22a, 22b in the vehicle width direction (see FIG. 1).

Further, the vehicle width direction outer end portion 24 of the floor cross member 16 has a front side flange 46a and a rear side flange 46b that are joined to the side sill 12 (side sill inner 62b) (see FIG. 2). In the vehicle front-rear direction, the rear flange 46b is joined (connected) to the side sill 12 at a position overlapping the vehicle front end portion 50 of the center pillar 48, and the front flange 46a is joined to the side sill 12 at a position ahead of the center pillar 48 with respect to the vehicle. (connected).

A floor frame 52 extending in the longitudinal direction of the vehicle is arranged on the lower surface of the floor panel 18 facing the ground. As shown in FIG. 4, the floor frame 52 includes an inner floor frame 54a that is adjacent to the floor tunnel 14 and arranged linearly along the floor tunnel 14, and an inner floor frame 54a that is adjacent to the side sill 12 and , and an outer floor frame 54b arranged to bend outward in the vehicle width direction from an intermediate portion in the middle.

As shown in FIGS. 3 and 4, the floor cross member 16 is arranged to cross the floor frame 52 (the inner floor frame 54a and the outer floor frame 54b). Further, the widened portion 30 of the floor cross member 16 is configured so as to widen from a position where it overlaps (intersects) with the outer floor frame 54b in the vertical direction of the vehicle toward the outer side in the vehicle width direction (side sill 12 side). (See FIG. 3).

Further, the floor cross member 16 is arranged at a position where at least a portion of the floor cross member 16 overlaps a vehicle front end portion 50 provided on the lower end side of the center pillar 48 in the vehicle front-rear direction.

As shown in FIG. 6, the floor frame 52 has a hat-shaped cross-section perpendicular to the axis, a lower wall 56a, a pair of side walls 56b, 56b that are continuous with the lower wall 56a and face each other, and an upper end of each side wall 56b. It has a continuous flange portion 56c. The flange portions (the front flange portion 28d and the rear flange portion 28e) of the floor cross member 16 and the flange portion 56c of the floor frame 52 are welded and fixed to the upper and lower surfaces of the floor panel 18, respectively.

In other words, the flanges (front flange 28d, rear flange 28e) of the floor cross member 16 are joined to the upper surface of the floor panel 18 (see FIG. 2), and the flange of the floor frame 52 is attached to the lower surface thereof. 56c is joined (see FIG. 6). In this case, at the crossing portion 58 where the flange portions (the front flange portion 28d and the rear flange portion 28e) of the floor cross member 16 and the flange portion 56c of the floor frame 52 intersect in the vertical direction, three members overlap each other. are welded together and welded together (see juncture of intersection 58 shown in FIG. 3).

Furthermore, as shown in FIG. 6, flanges 72a (72a) of the first seat brackets 22a, 22b (second seat brackets 26a, 26b) are joined to the upper surface thereof with the floor panel 18 therebetween. A flange portion 56c of the floor frame 52 (54a, 54b) is joined to the lower surface. In this case, the three members consisting of the seat brackets (22a, 22b, 26a, 26b), the floor panel 18, and the floor frame 52 are superimposed on each other in the vertical direction and simultaneously and integrally spot-welded. . At this welding portion, an adhesive (glue) G is interposed between the flange 72a and the upper surface of the floor panel 18 (see FIG. 6).

The floor tunnel 14 has a hat-shaped cross section perpendicular to its axis. The floor tunnel 14 includes an upper wall 60a, a pair of side walls 60b, 60b bent downward from the end of the upper wall 60a and opposed to each other in the vehicle width direction, and a pair of side walls 60b extending along the vehicle width direction from the lower ends of the side walls 60b. It has a pair of curved lower walls 60c, 60c.

The side sill 12 has a side sill outer 62a (see FIG. 1) arranged on the outside in the vehicle width direction and a side sill inner 62b (see FIG. 9) arranged on the inside in the vehicle width direction. A reinforcing member 64 that reinforces the cross section of the side sill 12 is provided between the side sill outer 62a and the side sill inner 62b in the cross section of the side sill 12 in the direction perpendicular to the axis (see FIG. 10). As shown in FIG. 10, the reinforcement member 64 is arranged at a position where the floor cross member 16 and the vehicle front end portion 50 of the center pillar 48 overlap in the vehicle front-rear direction when viewed from the side in the vehicle width direction. there is

The reinforcing member 64 is composed of a pair of bulkheads spaced apart along the vehicle front-rear direction, and is joined and fixed to the inner wall of the side sill inner 62b via a flange bent into an L-shaped cross section (Fig. 10). reference).

The vehicle 10 to which the vehicle body lower portion structure according to the present embodiment is applied is basically configured as described above, and the effects thereof will be described below.

In this embodiment, the vehicle width direction outside end portion 24 of the floor cross member 16 is provided with a widened portion 30 that widens in the vehicle front-rear direction toward the end portion on the side sill 12 side. The widened portion 30 includes both a front widened portion 32a that widens toward the front of the vehicle and a rear widened portion 32b that widens toward the rear of the vehicle at the outer end portion 24 of the floor cross member 16 in the vehicle width direction. ing.

In this embodiment, the vehicle width direction outside end portion 24 of the floor cross member 16 arranged to be sandwiched between the second seat brackets 26a and 26b is widened in the vehicle front-rear direction so that the floor cross member 16 is Even if the side impact load is input at a position offset in the longitudinal direction of the vehicle, the offset side impact load can be efficiently transmitted along the widened portion 30 of the floor cross member 16 (white outline in FIG. 5). See arrow A). As a result, in the present embodiment, it is possible to suppress the deformation of the vehicle interior due to the side impact load that is offset in the vehicle front-rear direction. Furthermore, in this embodiment, since the load transmission efficiency is improved, it is not necessary to arrange a plurality of floor cross members 16, and a single floor cross member 16 can be used. As a result, in this embodiment, it is possible to reduce the weight of the lower portion of the vehicle body, improve energy efficiency, and further increase the foot space for the occupant.

In this embodiment, the upper surface of the upper wall 28a of the floor cross member 16 is provided with a bead 36 that bulges upward and extends in the vehicle width direction. This bead 36 extends not only to the widened portion 30 located on the outer side in the vehicle width direction, but also to the positions of the first seat brackets 22a and 22b (the vicinity of the floor tunnel 14) located on the inner side of the widened portion 30 in the vehicle width direction. extended.

In this embodiment, a bead 36 extending inward in the vehicle width direction from the widened portion 30 is provided on the upper surface of the upper wall 28a of the floor cross member 16, thereby offsetting the floor cross member 16 in the longitudinal direction of the vehicle. Even if a side impact load is input to the floor cross member 16, the side impact load transmitted to the widened portion 30 can be reliably transmitted toward the inside of the floor cross member 16 in the vehicle width direction.

Furthermore, in the present embodiment, a floor frame 52 extending along the vehicle front-rear direction is arranged on the lower surface of the floor panel 18 facing the ground. The floor cross member 16 is arranged to cross the floor frame 52 (the inner floor frame 54a and the outer floor frame 54b). Further, the widened portion 30 of the floor cross member 16 is widened from a position where it overlaps with the floor frame 52 (outer floor frame 54b) in the vertical direction of the vehicle toward the outside in the vehicle width direction (side sill 12 side). is configured to

In the present embodiment, the width of the widened portion 30 is transmitted to the widened portion 30 by starting the widening of the widened portion 30 from the position overlapping the floor frame 52 (outer floor frame 54b) toward the outside in the vehicle width direction (toward the side sill 12). The side impact load can be reliably transmitted (distributed) to the vehicle width direction inner side of the floor cross member 16 and the floor frame 52 . Further, in the present embodiment, when a side impact load offset in the vehicle front-rear direction is transmitted to the widened portion 30, it is possible to prevent the widened portion 30 from breaking at the portion where the widening starts.

Furthermore, in this embodiment, the flange portions (the front flange portion 28d and the rear flange portion 28e) of the floor cross member 16 and the flange portion 56c of the floor frame 52 are welded and fixed to the upper and lower surfaces of the floor panel 18, respectively. ing. At the crossing portion 58 where the flange portions (front side flange portion 28d, rear side flange portion 28e) of the floor cross member 16 and the flange portion 56c of the floor frame 52 intersect in the vertical direction, three members are simultaneously and integrally formed. Welded.

In the present embodiment, the floor cross member 16 and the floor frame 52 are integrally welded at the intersection 58 , so that the offset side impact load input to the floor cross member 16 is smoothly applied to the floor frame 52 . can be transmitted (distributed) to Further, in the present embodiment, when an offset side impact load is transmitted to the widened portion 30, it is possible to prevent the widened portion 30 from breaking at the portion where the widening starts.

Furthermore, in the present embodiment, a recess 40 that is recessed toward the floor panel 18 (downward) is provided between the front bead 38a and the rear bead 38b. The recessed portion 40 extends along the longitudinal direction (vehicle width direction) of the floor cross member 16 and is configured such that the width dimension of the widened portion 30 in the vehicle front-rear direction increases.

In the present embodiment, a recess 40 is provided between the front bead 38a and the rear bead 38b, and the width of the recess 40 in the vehicle front-rear direction is increased in the widened portion 30. The offset side impact load can be reliably transmitted (distributed) to the vehicle width direction inner side of the floor cross member 16 and to the floor frame 52 .

Furthermore, in this embodiment, the vehicle width direction inner end portion 20 of the floor cross member 16 is connected to the floor tunnel 14 via the upper flange 44a, the front flange 44b and the rear flange 44c. First seat brackets 22a and 22b connected to the floor tunnel 14 are arranged in the longitudinal direction of the vehicle at the end portion of the floor cross member 16 on the side of the floor tunnel 14 (the portion near the inner end portion 20 in the vehicle width direction). ing. A recess 40 provided on the upper surface of the floor cross member 16 extends to a position overlapping the first seat brackets 22a, 22b in the vehicle width direction.

In the present embodiment, the concave portion 40 extends to a position overlapping the first seat brackets 22a and 22b in the vehicle width direction, so that the offset side impact load input to the floor cross member 16 is reduced by the first seat brackets 22a and 22b. 22b and floor tunnels 14.

Furthermore, in the present embodiment, the floor cross member 16 is arranged at a position where at least a portion of the floor cross member 16 overlaps the vehicle front end portion 50 provided on the lower end side of the center pillar 48 in the vehicle front-rear direction.

In the present embodiment, the floor cross member 16 is arranged at a position overlapping the vehicle front end portion 50 of the center pillar 48, so that the side impact load input from the center pillar 48 and the input from the vehicle front position of the center pillar 48 are applied. The side impact load and the side impact load can be efficiently transmitted to the floor cross member 16, respectively.

Furthermore, in this embodiment, the vehicle width direction outer end portion 24 of the floor cross member 16 has a front flange 46 a and a rear flange 46 b that are joined to the side sills 12 . In the vehicle front-rear direction, the rear flange 46b is joined (connected) to the side sill 12 at a position overlapping the vehicle front end portion 50 of the center pillar 48, and the front flange 46a is joined to the side sill 12 at a position ahead of the center pillar 48 with respect to the vehicle. (connected).

In this embodiment, the rear flange 46b of the floor cross member 16 overlaps the vehicle front end portion 50 of the center pillar 48, and the front flange 46a is joined to the side sill 12 at a vehicle front position relative to the center pillar 48. The side impact load input from 48 and the side impact load input from a position forward of the vehicle relative to the center pillar 48 can be efficiently transmitted to the floor cross member 16 .

Furthermore, in this embodiment, a reinforcing member 64 for reinforcing the cross section of the side sill 12 is provided between the side sill outer 62a and the side sill inner 62b in the cross section of the side sill 12 in the axial direction. The reinforcement member 64 is arranged at a position where the floor cross member 16 and the vehicle front end portion 50 of the center pillar 48 overlap in the vehicle front-rear direction.

In this embodiment, the reinforcement member 64 is arranged in the cross section of the side sill 12 at a position where the floor cross member 16 and the vehicle front end portion 50 of the center pillar 48 overlap in the vehicle front-rear direction. As a result, in this embodiment, the side impact load input to the center pillar 48 can be efficiently transmitted to the floor cross member 16 via the reinforcing member 64 .

REFERENCE SIGNS LIST 10 vehicle 12 side sill 14 floor tunnel 16 floor cross member 18 floor panel 20 vehicle width direction inner end 22a, 22b first seat bracket 24 vehicle width direction outer end 26a, 26b second seat bracket 28a upper wall 28b front wall 28c rear Wall 30 Widened portion 32a Front widened portion 32b Rear widened portion 36 Bead 40 Recess 46a Front flange 46b Rear flange 48 Center pillar 50 Vehicle front end 52 Floor frame 58 Intersection 64 Reinforcing member

Claims (9)

A vehicle body lower structure having a floor cross member that connects a side sill disposed on the outside in the vehicle width direction and a floor tunnel disposed in the center of the vehicle body and is sandwiched between seat brackets in the vehicle front-rear direction,
A vehicle body lower structure, wherein a vehicle width direction outer end portion of the floor cross member is provided with a widened portion that widens in the vehicle front-rear direction. In the vehicle body lower structure according to claim 1,
The floor cross member has an upper wall arranged on the upper surface, a front wall on the front side of the vehicle, and a rear wall on the rear side of the vehicle,
The upper surface of the upper wall is provided with beads extending along the front wall and the rear wall, respectively;
The vehicle body lower portion structure, wherein the bead extends to a vehicle width direction inner side of the widened portion. In the vehicle body lower structure according to claim 2,
A floor panel disposed between the pair of left and right side sills,
The lower surface of the floor panel facing the ground is provided with a floor frame extending in the longitudinal direction of the vehicle,
the floor cross member and the floor frame are arranged to cross each other;
The vehicle body lower portion structure, wherein the widened portion is configured to widen from a position where it overlaps with the floor frame in a plan view toward an outer side in a vehicle width direction. In the vehicle body lower structure according to claim 3,
The floor frame has flange portions on both sides in the extending direction,
The floor cross member has flange portions on both sides in the extending direction,
the flange portion of the floor frame and the flange portion of the floor cross member are welded to the floor panel,
The vehicle body lower structure, wherein the flange portion of the floor frame and the flange portion of the floor cross member intersect each other in the vertical direction, and are overlapped and welded to each other. In the vehicle body lower structure according to claim 2,
Between the bead extending along the front wall and the bead extending along the rear wall, a recess recessed toward the floor panel is provided,
The vehicle body lower portion structure, wherein the recess extends along the longitudinal direction of the floor cross member, and the width dimension in the vehicle front-rear direction increases at the widened portion. In the vehicle body lower structure according to claim 5,
A vehicle width direction inner end portion of the floor cross member is connected to a floor tunnel,
A seat bracket connected to the floor tunnel is arranged in the longitudinal direction of the vehicle at an end of the floor cross member on the floor tunnel side,
The vehicle body lower portion structure, wherein the recess extends to a position overlapping the seat bracket in the vehicle width direction. In the vehicle body lower structure according to claim 2,
The vehicle body lower portion structure, wherein the floor cross member is arranged at a position where at least a portion thereof overlaps with a vehicle front end portion of the center pillar in the vehicle front-rear direction. In the vehicle body lower structure according to claim 7,
the vehicle width direction outer end of the floor cross member has a rear flange and a front flange connected to the side sill;
In the vehicle front-rear direction, the rear flange is connected at a position overlapping the vehicle front end of the center pillar, and the front flange is connected at a position forward of the vehicle relative to the center pillar. structure. In the vehicle body lower structure according to claim 7,
A reinforcing member is provided in the cross section of the side sill in the direction perpendicular to the axis to reinforce the cross section of the side sill,
The vehicle body lower portion structure, wherein the reinforcing member is arranged at a position where the floor cross member and the vehicle front end portion of the center pillar overlap with each other in the vehicle front-rear direction.

Images