JP2004082978A - Car floor substructure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a car floor substructure capable of reducing a bending moment to work on a rear floor cross member without causing extensive increase of weight. <P>SOLUTION: An input load to generate the bending moment of the cross member 50 is dispersed in the extending direction (axial direction) of the cross member 50 by arranging a pair of left and right rear side members 30, 40 in the inside Inr in the car body cross direction rather than a pair of left and right side sills 10, 20, forming both end edges 53, 54 of the cross member 50 by inclining them at inclination θ(0°<θ<90°) against the car body longitudinal direction, respectively making inclined end edges 53, 54 of the cross member 50 contact with front parts of the rear side members 30, 40 and providing inclined ribs 34, 44 continued to vertical walls 12, 22 of the inside Inr in the car body cross direction of the side sills 10, 20. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle body floor lower structure, and more particularly to an improvement in a load distribution structure when a load is input in the front-rear direction and the width direction of a vehicle body.
[0002]
[Prior art]
Conventionally, a pair of front rear floor side members extending in the vehicle body front-rear direction and extending in the vehicle body width direction and extending in the vehicle body front-rear direction, and the front end portions thereof correspond to each other as a vehicle floor lower structure. It is known to have a pair of rear rear floor side members connected to the rear end of the front rear floor side member, and a rear floor cross member extending in the vehicle width direction and having both ends connected to the front rear floor side member. Have been.
[0003]
In such a lower body floor structure, for example, as shown in JP-A-2001-347966, the end of the rear floor cross member intersects with the front rear floor side member and the front end of the rear rear floor side member. Of the rear floor cross member is opposed to the end face of the rear floor cross member via a wall member such as a lid member.
[0004]
[Problems to be solved by the invention]
By the way, the above-described lower structure of the vehicle body floor has a structure in which the rear floor cross members are arranged at right angles to the front and rear rear floor side members, and the front ends of the rear rear floor side members vertically abut the respective end side surfaces of the rear floor cross members. Therefore, when a load in the vehicle front-rear direction is applied to one of the left and right rear rear floor side members, the load transmitted from the rear rear floor side member to the rear floor cross member causes the other one of the other members separated in the vehicle lateral direction. A bending moment acts on the rear floor cross member around the intersection of the rear floor side member and the rear floor cross member, and the rear rear floor side member also rotates around the intersection with the rear floor cross member. Can not get There is a problem.
[0005]
As a measure to solve this problem, it is conceivable to improve the bending rigidity by enlarging the cross-sectional area of the rear floor cross member or increasing the plate thickness in order to obtain a sufficient vehicle reaction force.
[0006]
However, such a measure is not preferable because the weight of the rear floor cross member increases and the body weight increases.
[0007]
When the rear floor cross member is an extruded member made of a light alloy such as an aluminum alloy, the thickness of the rear floor cross member is increased or the cross-sectional shape of the rear floor cross member is changed to “ Although it is conceivable to improve the bending stiffness in the shape of a “ta”, there is a problem that the advantage of weight reduction due to the use of a light alloy is offset or reduced.
[0008]
The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a lower body floor structure capable of reducing a bending moment acting on a rear floor cross member without causing a significant increase in weight. I do.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the vehicle floor lower structure according to the present invention is characterized in that a front end of a rear rear floor side member and both end edges of a rear floor cross member connected to the front rear floor side member are connected to the front and rear of the vehicle body via inclined ribs. A part of the load input from the rear of the vehicle body in the direction in which the rear rear floor side member extends, thereby allowing a portion of the load input from the rear of the vehicle body to extend in the direction in which the rear rear floor side member extends. And a part of the load input to the rear floor cross member from the side of the vehicle body is dispersed in the extending direction of the rear floor side member orthogonal to the rear floor cross member.
[0010]
That is, the vehicle body floor lower structure according to the present invention extends in the vehicle body front-rear direction, and extends in the vehicle body front-rear direction with a pair of front rear floor side members separated from each other in the vehicle body width direction. A pair of rear rear floor side members connected to the rear end of the front rear floor side member, and a rear floor cross member extending in the vehicle width direction and having both ends connected to the front rear floor side member. In the vehicle body floor lower structure, the pair of rear rear floor side members are disposed more inward in the vehicle width direction than the pair of front rear floor side members, and both end edges of the rear floor cross member are inclined with respect to the vehicle longitudinal direction. Abutting against the inclined edge of the rear floor cross member at the front of the rear rear floor side member. An inclined rib connected to a longitudinally inner wall in the vehicle width direction of the rear rear floor side member; and a front and rear extending from the longitudinally outer vertical wall of the rear rear floor side member to the vehicle body and connected to the inclined rib. A rib, and right and left ribs connected to a vertical wall on the inner side in the vehicle width direction of the front rear floor side member from a connection portion between the inclined rib and the front and rear ribs are formed.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a vehicle body floor lower structure according to the present invention will be described with reference to the drawings.
[0012]
As shown in FIG. 1, a lower body floor structure 100 according to the present embodiment includes a pair of side sills (front rear floor side members) 10 and 20 extending in the vehicle front-rear direction and spaced from each other in the vehicle width direction. Rear side members (rear rear floor side members) extending in the front-rear direction of the vehicle body, offset from the side sills 10, 20 inward in the vehicle width direction, and connected to the rear ends of the corresponding side sills 10, 20 respectively. 30 and 40, and a cross member 50 extending in the width direction of the vehicle body and intersecting the front ends of the left and right rear side members 30, 40 and having both end edges 53, 54 connected to the side sills 10, 20. Configuration.
[0013]
Here, the side sills 10 and 20 and the rear side members 30 and 40 are described in detail. Each of the rear side members 30 and 40 is curved toward the outer side Otr in the vehicle width direction, and the vertical walls 12 on the inner side Inr of the side sills 10 and 20 in the vehicle width direction. , 22 are connected.
[0014]
Further, both end edges 53 and 54 of the cross member 50 are formed to be inclined by an angle θ (0 ° <θ <90 °) with respect to the vehicle longitudinal direction.
[0015]
Note that the inclination angles θ of the both end edges 53 and 54 are formed symmetrically to the left and right, but are not necessarily limited to the symmetrical ones, and the inclination angle of the left end edge 54 is larger than the inclination angle of the right end edge 53. The angle may be set to be large, or the inclination angle of the right edge 53 may be set to be larger than the inclination angle of the left edge 54.
[0016]
However, it is better to set the left-right balance symmetrically, and it is preferable to set the symmetrical inclination angle.
[0017]
The inclined direction is such that the vertical wall 52 on the rear side Rr is shorter than the vertical wall 51 on the front side Fr in the vehicle longitudinal direction.
[0018]
Further, inclined ribs 34 and 44 are formed at the front portions of the rear side members 30 and 40 to abut against the inclined edges 53 and 54 of the cross member 50, respectively.
[0019]
One end of each of the inclined ribs 34, 44 is connected to the vertical walls 32, 42 of the rear side members 30, 40 on the inner side Inr in the vehicle width direction.
[0020]
The front and rear ribs 35, 45 extending from the vertical walls 31, 41 of the outer side Otr of the rear side members 30, 40 to the vehicle front Fr and connected to the inclined ribs 34, 44 are provided on the respective rear side members 30, 40. Is provided.
[0021]
Further, each of the rear side members 30, 40 is provided with side sill ribs 37, 47 which abut on the extended portions of the cross member 50 among the vertical walls 12, 22 on the inner side Inr of the side sills 10, 20 in the vehicle width direction.
[0022]
Further, left and right ribs 36 and 46 extending from the intersection of the inclined ribs 34 and 44 and the front and rear ribs 35 and 45 to the side sill ribs 37 and 47 toward the outer side Otr in the vehicle width direction are provided at the rear side members. 30 and 40.
[0023]
In addition, cross member ribs 38, 39, 48, and 49 are formed on the rear side members 30, 40 to abut against the vertical walls 51, 52 extending in the vehicle width direction of the cross member 50, respectively.
[0024]
Next, the operation of the vehicle body floor lower structure 100 according to the present embodiment will be described with reference to FIGS.
[0025]
First, a case where a load FR from the rear Rr of the vehicle body toward the front Fr of the vehicle body is input to the left rear side member 40 in the vehicle body floor lower structure 100 thus configured will be described.
[0026]
A part of the load FR input to the left rear side member 40 is transmitted to the front and rear ribs 45 from the vertical wall 40 of the rear side member 40 on the outer side Otr in the vehicle width direction.
[0027]
The load F1 transmitted to the front and rear ribs 45 is transmitted to the inclined ribs 44 from the front ends of the front and rear ribs 45.
[0028]
Here, as shown in FIG. 2B, the load F1 input to the inclined rib 44 is crossed orthogonally to a component along the direction in which the inclined rib 44 extends (the angle θ with respect to the longitudinal direction of the vehicle body). It is decomposed into components input to the left edge 54 of the member 50.
[0029]
The directional component along the direction in which the inclined rib 44 extends is F1 cos θ, while the directional component orthogonal to this is F1 sin θ.
[0030]
Therefore, the direction component F1cos θ along the direction in which the inclined rib 44 extends is transmitted from the front end of the inclined rib 44 to the left side sill 20.
[0031]
On the other hand, the orthogonal direction component F1 sin θ is input to the cross member 50 from the edge 54 of the cross member 50.
[0032]
Here, when the component F1 sin θ input to the cross member 50 is decomposed into a component in the extending direction of the cross member 50, that is, a component in the vehicle width direction and a component orthogonal thereto, the extending direction component of the cross member 50 becomes F1 sin θ cos θ = (1/2) F1sin2θ.
[0033]
Therefore, according to the conventional body floor lower structure, the load F1, which is input to the left end of the cross member as a direction component orthogonal to the cross member and acts as a bending moment centered on the right end of the cross member, A part is distributed to the side sill 20 via the inclined ribs 44, and the other part does not contribute to the bending moment about the right end of the cross member 50 at all. The acting axial compression load (1/2) is dispersed as F1 sin2θ.
[0034]
Therefore, the bending moment acting on the cross member 50 can be reduced as compared with the related art.
[0035]
Further, the axial compressive load (）) F1 sin2θ transmitted to the cross member 50 is transmitted to the inclined rib 34 from the edge 53 opposite to the edge 54 on which the load is input.
[0036]
Part of the load transmitted to the inclined ribs 34 is distributed to the right side sill 10 along the direction in which the inclined ribs 34 extend, and the other part is transmitted via the left and right ribs 36 and the side sill ribs 37. And transmitted to the right side sill 10.
[0037]
Further, another part is distributed to the right rear side member 30 via the front and rear ribs 35.
[0038]
As described above, according to the lower body floor structure 100 according to the present embodiment, when the load FR in the front-rear direction from the rear body Rr toward the front body Fr is input, the load FR acts on the cross member 50 more than before. Since the bending moment can be reduced, the necessity of increasing the rigidity of the cross member 50 with respect to the bending moment is reduced, and an increase in the weight of the vehicle body floor lower structure for improving the rigidity can be suppressed.
[0039]
Further, since the input load FR can be dispersed to more members, the vehicle body reaction force with respect to the input load FR increases more than before, and the performance of absorbing the input energy from behind can be improved. .
[0040]
The above operation is performed when the load FR is input to the left rear side member 40. However, when the load FR is input to the right rear side member 30, the load transmission path changes symmetrically. Except for the above, it has the same effect and exhibits the same effect as the above-described effect.
[0041]
Next, a case where a load FS from the outside of the vehicle body to the right side of the vehicle body is input to the left side sill 20 in the vehicle body floor lower structure 100 thus configured will be described.
[0042]
A part of the load FS input to the left side sill 20 is transmitted to the inclined ribs 44 via the side sill ribs 47 and the right and left ribs 46.
[0043]
Here, the load F2 input to the inclined rib 44 acts as an axial compressive load in the extending direction of the cross member 50, but a part of the load F2 is dispersed from the inclined rib 44 to the left rear side member 40.
[0044]
The axial compressive load F2 transmitted to the cross member 50 is transmitted to the inclined rib 34 from the edge 53 opposite to the edge 54 on which the load is input.
[0045]
Part of the load transmitted to the inclined ribs 34 is distributed to the right side sill 10 along the direction in which the inclined ribs 34 extend, and the other part is transmitted via the left and right ribs 36 and the side sill ribs 37. And transmitted to the right side sill 10.
[0046]
Further, another part is distributed to the right rear side member 30 via the front and rear ribs 35.
[0047]
As described above, according to vehicle body floor lower structure 100 according to the present embodiment, when load FS is input from the side of the vehicle body, the bending moment acting on cross member 50 can be reduced as compared with the related art. Therefore, the necessity of increasing the rigidity of the cross member 50 against the bending moment is reduced, and an increase in the weight of the vehicle body floor lower structure for improving the rigidity can be suppressed.
[0048]
Further, since the input load FS can be dispersed to more members, the vehicle body reaction force against the input load FS is increased as compared with the related art, and the performance of absorbing rearward input energy can be improved. .
[0049]
The inclination angle θ of the inclined rib may be 0 ° <θ <90 ° as described above, but is preferably set to 30 ° ≦ θ ≦ 60 ° in order to enhance the load transmission efficiency. , 40 ° ≦ θ ≦ 50 °.
[0050]
In addition, the inclined ribs 34 and 44 extend from the end surface of the cross member 50 to the inner vertical walls 12 and 22 of the side sills 10 and 20, and abut against or close to the front and rear vertical walls 51 and 52 of the cross member 50. The ribs 38, 39, 48, 49 and the side sill ribs 37, 47 that abut along the inner vertical walls 12, 22 of the side sills 10, 20 to which the left and right ribs 36, 46 are connected, are provided. The coupling strength of the cross member 50, the rear side members 30, 40, and the side sills 10, 20 can be improved, and the strength of the vehicle body floor lower structure 100 against input loads from the rear and side of the vehicle can be improved. The transmission efficiency can be further improved, and the energy absorption efficiency can be improved.
[0051]
In addition, it is preferable that the cross member 50 is integrally formed by an extruded material.
[0052]
Conventional cross members are formed, for example, by welding two press members to each other. Compared with a cross member formed in this manner, a cross member formed of an extruded material has a higher axial force carrying performance. Because of its superiority, when a strong load in the vehicle longitudinal direction is input to the rear side member 40 (or 30) from the rear of the vehicle body and a strong load is transmitted to the cross member 50, the shaft of the cross member 50 due to the load is transmitted. Although the load applied in the direction becomes large, the cross member of the extruded material having excellent axial force carrying performance is provided on the rear side member 30 (or 40) or the side sill 10 (or 20) opposite to the load input side. The load can be appropriately dispersed.
[0053]
Further, it is preferable that the rear side members 30, 40 are formed integrally with the ribs 34 to 39, 44 to 49 by a casting material.
[0054]
The rear side members 30, 40 configured as described above are different from those in which the ribs 34 to 39, 44 to 49 are formed as separate parts from the other parts of the rear side members 30, 40, and are fixed by welding or the like. This is because it can be manufactured efficiently and at low cost.
[0055]
【The invention's effect】
As described above, according to the vehicle body floor lower structure according to the present invention, the front end of the rear rear floor side member and both end edges of the rear floor cross member connected to the front rear floor side member are connected to the vehicle body via the inclined ribs. A part of the load input in the extending direction of the rear rear floor side member from the rear of the vehicle body by the inclination of the rear rear side member through the inclined ribs extends through the inclined rib. Dispersed in the axial direction (extending direction) of the rear floor cross member orthogonal to the direction, the bending moment acting on the rear floor cross member (depending on the load acting orthogonally to the extending direction of the rear floor cross member) can be reduced. it can.
[0056]
Further, a part of the load transmitted in the axial direction of the rear floor cross member further obliquely contacts the front rear floor side member on the side opposite to the side where the load is input and the opposite edge of the rear floor cross member. Since the load is transmitted to the contacting rear floor side member, the range of the elements in which the load is dispersed is expanded, and the load borne by each element is reduced.
[0057]
Therefore, it is not necessary to increase the thickness of the rear floor cross member or change the cross-sectional shape to take measures to increase the weight that contributes to the improvement in bending rigidity.
[0058]
Further, by expanding the range of the elements in which the load is dispersed, the vehicle body reaction force is increased with respect to the conventional vehicle body floor lower structure, and the performance of absorbing rear collision energy can be improved.
[0059]
Furthermore, according to the vehicle body floor lower structure according to the present invention, the front end of the rear rear floor side member and both end edges of the rear floor cross member connected to the front rear floor side member are interposed with respect to the vehicle front-rear direction via the inclined ribs. A part of the load input from the side of the vehicle body in the extending direction of the rear floor cross member at an end opposite to the end on the load input side via the inclined rib. Therefore, it is dispersed also in the extending direction of the rear rear floor side member, and the axial compression force acting on the rear floor cross member can be reduced.
[0060]
Therefore, it is not necessary to increase the weight of the rear floor cross member to increase the plate thickness or change the cross-sectional shape of the rear floor cross member.
[0061]
In addition, by expanding the range of the element in which the load is dispersed, the vehicle body reaction force is increased as compared with the conventional body floor lower structure, and the performance of absorbing side collision energy can be improved.
[0062]
Furthermore, part of the load input from the side of the vehicle body in the extending direction of the rear floor cross member is also distributed to the front and rear rear floor side members on the load input side, so that the performance of absorbing collision energy can be improved.
[Brief description of the drawings]
FIG. 1 is a view showing a specific embodiment of a vehicle body floor lower structure according to the present invention, wherein (a) is a plan view and (b) is a cross-sectional view taken along line AA in (a). (C) is a cross-sectional view taken along the line BB in (a).
FIG. 2 is a diagram illustrating transmission of a load when a load is input from the rear of the vehicle body to the vehicle body floor lower structure illustrated in FIG. 1;
FIG. 3 is a diagram illustrating transmission of a load when a load is input from the side of the vehicle body to the vehicle body floor lower structure illustrated in FIG. 1;
[Explanation of symbols]
10,20 side sill (front side rear floor side member)
11, 21, 31, 41 Outer vertical wall 12, 22, 32, 42 Inner vertical wall 30, 40 Rear side member (rear rear floor side member)
33, 43 Bottom walls 34, 44 Inclined ribs 35, 45 Front and rear ribs 36, 46 Left and right ribs 37, 47 Side sill ribs (side member ribs)
38, 39, 48, 49 Cross member rib 50 Cross member (rear floor cross member)
51 Front wall 52 Rear walls 53, 54 Edge 100 Body floor lower structure Fr Car body front Rr Car body rear Otr Car width direction outside Inr Car width direction inside θ Arrangement angle of inclined ribs with respect to vehicle body front-rear direction FR Load FS acting from the rear Load F1, F2 acting from the side Load acting on the cross member

Claims (4)

A pair of front rear floor side members extending in the vehicle front-rear direction and spaced apart from each other in the vehicle width direction; and a front end extending in the vehicle front-rear direction and having a front end connected to a corresponding rear end of the front rear floor side member. A rear floor cross member having a pair of rear rear floor side members and a rear floor cross member extending in the vehicle width direction and having both ends connected to the front rear floor side member.
The pair of rear rear floor side members are disposed more inward in the vehicle width direction than the pair of front rear floor side members,
Both end edges of the rear floor cross member are formed to be inclined with respect to the vehicle longitudinal direction,
An inclined rib which is in contact with an inclined edge of the rear floor cross member and which is connected to a vertical wall on the inner side in the vehicle width direction of the rear rear floor side member; a front rib of the rear rear floor side member; Front and rear ribs extending forward from the vertical wall on the vehicle width direction and connected to the inclined ribs; and a vertical wall on the inner side in the vehicle width direction of the front rear floor side member from a connection portion between the inclined ribs and the front and rear ribs. And a left and right rib connected to the vehicle body floor structure. A cross member rib that is in contact with each vertical wall extending in the vehicle width direction of the rear floor cross member at a front portion of the rear rear floor side member, and a vertical portion to which the left and right ribs of the front rear floor side member are connected. With a side member rib that abuts along the wall,
The inclined rib is formed so that a front end extends to a vertical wall inside the vehicle width direction of the front rear floor side member,
2. The vehicle body floor lower structure according to claim 1, wherein the left and right ribs are connected to a vertical wall inside the vehicle body width direction of the front rear floor side member via the side member rib. 3. The vehicle body floor lower structure according to claim 1, wherein the rear floor cross member is integrally formed of an extruded material. The vehicle body floor lower structure according to any one of claims 1 to 3, wherein the rear rear floor side member is integrally formed with a cast material together with each of the ribs.

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