JP2007283976A - Vehicle substructure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain a collision load to be absorbed at the time of a side collision of the vehicle high for a long time. <P>SOLUTION: In the vehicle substructure 10, at the time of a side collision of the vehicle 12, a collision load is transmitted from a center pillar 56 through a rocker 48 to a front cross member 36 and a rear cross member 40 and absorbed. The front cross member 36 and the rear cross member 40 are displacedly disposed in the vehicle forward-rearward direction being close to each other. Subsequently after the collision load absorbed by the front cross member 36 reaches the peak load, the collision load absorbed by the rear cross member 40 reaches the peak load. The collision load to be absorbed can thus be maintained high for a long time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle lower structure in which a cross member is formed at a step portion between a first floor and a second floor of a vehicle.

  As a vehicle lower part structure, there is one in which a cross member is formed at a step part (hanging part) between a front floor and a rear floor (see, for example, Patent Document 1).

In such a vehicle lower structure, it is preferable that the collision load absorbed by the cross member at the time of a side collision of the vehicle can be maintained high for a long time.
JP 2002-19643 A

  An object of the present invention is to obtain a vehicle lower structure capable of maintaining a high collision load absorbed at the time of a side collision of a vehicle for a long time in consideration of the above fact.

  The vehicle lower structure according to claim 1 includes a first floor that constitutes a floor of the vehicle, a second floor that constitutes the floor and is disposed on the vehicle upper side of the first floor, the first floor, and the And a pair of cross members that are formed in a closed cross-sectional shape at a step portion with respect to the second floor, extend in the vehicle width direction, and are displaced in the vehicle front-rear direction.

  The vehicle lower structure according to claim 2 is the vehicle lower structure according to claim 1, wherein the rocker is disposed outside the floor in the vehicle width direction and extends in the vehicle front-rear direction, and the load input to the rocker. And a load transmitting means for transmitting the power to the pair of cross members.

  The vehicle lower structure according to claim 3 is the vehicle lower structure according to claim 1 or 2, wherein the cross member on the vehicle rear side is arranged on the vehicle upper side of the cross member on the vehicle front side, and the vehicle A tank is arranged on the vehicle lower side of the cross member on the rear side.

  In the vehicle lower structure according to the first aspect, the first floor and the second floor constitute a vehicle floor, and the second floor is arranged on the vehicle upper side of the first floor. Furthermore, a pair of cross members formed in a closed cross-sectional shape at the step portion between the first floor and the second floor extend in the vehicle width direction.

  Here, the pair of cross members are arranged shifted in the vehicle front-rear direction. For this reason, at the time of a side collision of the vehicle, after the collision load absorbed by one cross member becomes a peak load, the collision load absorbed by the other cross member can become a peak load. The collision load absorbed by can be maintained high for a long time.

  In the vehicle lower structure according to the second aspect, the rocker disposed on the outer side in the vehicle width direction of the floor extends in the vehicle front-rear direction.

  Here, the load transmitting means transmits the load input to the rocker to the pair of cross members. For this reason, at the time of a side collision of the vehicle, the pair of cross members can reliably absorb the collision load.

  In the vehicle lower structure according to the third aspect, the cross member on the rear side of the vehicle is disposed on the upper side of the cross member on the front side of the vehicle, and the tank is disposed on the lower side of the cross member on the rear side of the vehicle. For this reason, the tank capacity can be secured on the vehicle lower side of the cross member on the vehicle rear side.

  FIG. 1 is a plan view of a vehicle lower structure 10 according to an embodiment of the present invention as viewed from above the vehicle, and FIG. 2 shows a vehicle 12 configured by applying the vehicle lower structure 10. Is shown in a side view as seen from the left side of the vehicle. Further, FIG. 3 shows a main part of the vehicle lower structure 10 in a sectional view as seen from the left side of the vehicle. In the drawings, the front side of the vehicle is indicated by an arrow FR, the right side of the vehicle is indicated by an arrow RH, and the upper side of the vehicle is indicated by an arrow UP.

  In the vehicle lower structure 10 according to the present embodiment, a front floor portion 18 is provided on the floor 16 of the passenger compartment 14 on the vehicle front side, and a center floor portion 20 is provided on the vehicle rear side of the front floor portion 18. A rear floor portion 22 is provided on the vehicle rear side of the center floor portion 20.

  A plate-like front floor panel 24 (first floor panel) as a first floor is provided at the vehicle lower end of the front floor portion 18. A plate-like front upper panel 26 is provided on the vehicle upper side of the front floor panel 24, and the front upper panel 26 is supported by the front floor panel 24 via a support member (not shown).

  The center floor portion 20 is provided with a plate-like center floor panel 28 (second floor panel) as a second floor, and the center floor panel 28 is disposed on the vehicle upper side of the front floor panel 24 and the front upper panel 26. Has been.

  A step portion 30 is provided between the front floor panel 24 and the center floor panel 28, and a plate-like lower cross panel 32 as a lower cross panel is provided on the vehicle lower side of the step portion 30. Yes. The lower cross panel 32 includes a front cross portion 32A having a substantially L-shaped cross section on the front side of the vehicle and a rear cross portion 32B having a substantially L-shaped cross section on the rear side of the vehicle. The front cross portion 32A is a rear cross. It is arranged on the lower side of the vehicle compared to the part 32B.

  The front cross portion 32A has a vehicle front side portion disposed horizontally, and a vehicle rear side portion extended to the vehicle upper side. The vehicle front side end of the front cross portion 32A is connected to the vehicle rear side end of the front floor panel 24. At the same time, the vehicle rear side end of the front cross portion 32A is horizontally disposed and integrated with the vehicle front side end of the rear cross portion 32B. The rear cross portion 32B has a vehicle front side portion arranged horizontally and a vehicle rear side portion extended to the vehicle upper side. The vehicle rear side end of the rear cross portion 32B is arranged horizontally, and the center floor panel 28 Is connected (welded) to the front end of the vehicle.

  A front cross panel 34 having a substantially L-shaped cross section constituting the upper cross panel is provided on the vehicle front side and the vehicle lower side of the step portion 30. The front cross panel 34 has a vehicle rear side portion that is horizontal. Arranged and the vehicle front side portion extends to the vehicle lower side. The vehicle front side end of the front cross panel 34 is horizontally disposed and joined (welded) to the vehicle rear side end of the front floor panel 24 and the vehicle front side end of the lower cross panel 32 (front cross portion 32A). The vehicle rear side end of the cross panel 34 is coupled (welded) to the vehicle front-rear direction intermediate portion of the lower cross panel 32 (the vehicle rear side end of the front cross portion 32A). As a result, the front cross panel 34 and the front cross portion 32A of the lower cross panel 32 form a front cross member 36 having a polygonal (for example, rectangular) closed cross-section (tubular) shape as a cross member. The member 36 constitutes the front floor portion 18 with the upper surface (the upper surface of the front cross panel 34) disposed at the same height as the upper surface of the front upper panel 26.

  A rear cross panel 38 having a substantially L-shaped cross section that constitutes an upper cross panel is provided on the rear side and the upper side of the stepped portion 30. The rear cross panel 38 has a rear side portion that is horizontal. Arranged and the vehicle front side portion extends to the vehicle lower side. The vehicle front side end of the rear cross panel 38 is horizontally arranged and coupled (welded) to the vehicle front-rear direction intermediate portion of the lower cross panel 32 (vehicle front side end of the rear cross portion 32B), and the vehicle of the front cross panel 34 The vehicle rear side end of the rear cross panel 38 is connected (welded) to the vehicle rear side end of the lower cross panel 32 (rear cross portion 32B), and the vehicle front side end of the center floor panel 28 is connected to the rear side end. Have been contacted. Thereby, the rear cross panel 38 and the rear cross portion 32B of the lower cross panel 32 form a polygonal (for example, pentagonal) closed cross-section (tubular) rear cross member 40 as a cross member. The member 40 has a top surface (the top surface of the rear cross panel 38) disposed at the same height as the top surface of the center floor panel 28, and constitutes the center floor portion 20.

  On the center floor portion 20, a seat 42 (rear seat) is fixed at the front portion of the vehicle. An occupant 44 is seated on the seat 42 facing the front of the vehicle, and a leg portion 44A of the occupant 44 is placed on the vehicle rear side portion of the front floor portion 18.

  A fuel tank 46 as a tank is provided near the vehicle lower side of the center floor portion 20, and the fuel tank 46 is disposed on the vehicle lower side of the center floor panel 28, and is a vehicle front side portion and a vehicle lower side. The portion extends to the vehicle lower side of the rear cross member 40.

  On both outer sides in the vehicle width direction of the front floor portion 18 and the center floor portion 20, rocker 48 having a substantially rectangular tube shape is provided. The rocker 48 extends in the vehicle front-rear direction and serves as a front cross as a load transmission means. The member 36 and the rear cross member 40 are joined (welded) by spot welding, for example.

  An outer reinforcement 50 that constitutes a load transmission means is fixed to the outer portion of the rocker 48 in the vehicle width direction, and the outer reinforcement 50 has a substantially horizontal U-shaped cross section that is open inward in the vehicle width direction. Thus, the rocker 48 is reinforced. In the rocker 48, a bulk 52 constituting load transmitting means is provided, and the bulk 52 is disposed at a position where the vehicle front-rear direction position partially overlaps the vehicle front-rear direction position of the front cross member 36. . The bulk 52 is formed in a rectangular parallelepiped container shape whose inner side surface in the vehicle width direction is opened, and the bulk 52 is fixed in the outer reinforcement 50 to reinforce the rocker 48 and the outer reinforcement 50.

  On the rocker 48, a front pillar 54 having a substantially rectangular tube shape as a pillar is fixed at the front end of the vehicle, and the front pillar 54 extends in the vehicle vertical direction. On the rocker 48, an approximately rectangular cylindrical center pillar 56 as a pillar is fixed above the bulk 52 in the vehicle, and the center pillar 56 extends in the vehicle vertical direction.

  A front side door 58 and a rear side door 60 serving as doors are rotatably supported on the front pillar 54 and the center pillar 56, respectively. The front side door 58 has an opening 62 (front opening) on the front side surface of the vehicle 12. And the rear side door 60 closes the opening 64 (rear opening) on the rear side of the side surface of the vehicle 12.

  Next, the operation of the present embodiment will be described.

  In the vehicle lower structure 10 having the above-described configuration, when a collision load is input to the rear side door 60 and the center pillar 56 from the outer side in the vehicle width direction and is input from the center pillar 56 to the rocker 48 at the time of a side collision of the vehicle 12. Is transmitted from the rocker 48 to the front cross member 36 and the rear cross member 40 and absorbed.

  Here, the front cross member 36 and the rear cross member 40 are arranged so as to be shifted in the vehicle front-rear direction in a state of being close to each other. In particular, the vehicle front side surface of the front cross member 36 and the vehicle front side surface of the rear cross member 40 are shifted in the vehicle front-rear direction, and the vehicle rear side surface of the front cross member 36 and the vehicle rear side surface of the rear cross member 40 are arranged. Are shifted in the vehicle longitudinal direction.

  Therefore, as shown in FIGS. 4 and 5, the collision load absorbed by the front cross member 36 closer to the center pillar 56 (the generated load of the front cross member 36 shown by line A in FIGS. 4 and 5) is the peak load. The collision load absorbed by the rear cross member 40 far from the center pillar 56 continuously (before the collision load absorbed by the buckling (collapse) of the front cross member 36 decreases from the peak load). The load generated by the rear cross member 40 indicated by the line B in FIGS. 4 and 5 is the peak load. Thus, unlike the case where the front cross member 36 and the rear cross member 40 are not shifted in the vehicle front-rear direction (the load generated by the front cross member 36 and the rear cross member 40 shown by line D in FIG. 4), the front cross member The collision load absorbed by the member 36 and the rear cross member 40 (the load generated by the front cross member 36 and the rear cross member 40 shown by line C in FIG. 4) can be maintained high for a long time.

  Further, the outer reinforcement 50 and the bulk 52 in the rocker 48 transmit the collision load input to the rocker 48 to the front cross member 36 and the rear cross member 40. For this reason, the front cross member 36 and the rear cross member 40 can reliably absorb the collision load.

  In addition, by adjusting the coupling strength of the front cross member 36 and the rear cross member 40 to the rocker 48 (for example, the number of spot welding points) and the distance in the vehicle longitudinal direction from the center pillar 56, the front cross member 36 and The magnitude and timing of the collision load transmitted to the rear cross member 40 can be adjusted. For this reason, the magnitude | size of the peak load which the front cross member 36 and the rear cross member 40 generate | occur | produces, and the difference in generation | occurrence | production time can be adjusted.

  Furthermore, the front cross member 36 and the rear cross member 40 have a closed cross-sectional shape to increase the axial compression resistance (buckling load) in the vehicle width direction. For this reason, the yield strength in the vehicle width direction of the passenger compartment 14 can be increased.

  In addition, since two cross members (the front cross member 36 and the rear cross member 40) are provided, the axial compression strength (buckling) of each cross member in the vehicle width direction as compared with the case where one cross member is provided. Load) can be reduced.

  Further, the front side and lower side parts of the fuel tank 46 arranged on the lower side of the vehicle on the center floor panel 28 are below the rear cross member 40 arranged on the upper side of the front cross member 36 and on the rear side of the vehicle. Stretched to the side. For this reason, the capacity of the fuel tank 46 can be secured.

  Further, the rear cross member 40 on the upper side of the vehicle is disposed on the rear side of the front cross member 36 on the lower side of the vehicle. For this reason, the occupant 44 seated on the seat 42 can pull the leg portion 44A rearward of the vehicle past the front cross member 36 to just before the rear cross member 40.

  In the present embodiment, the front cross member 36 and the rear cross member 40 are arranged close to each other. However, the front cross member 36 and the rear cross member 40 do not have to be arranged close to each other. It is sufficient if the collision load absorbed by the front cross member 36 and the collision load absorbed by the rear cross member 40 at the time of a collision are continuous with the peak load (without opening time).

It is the top view seen from the vehicles upper part which shows the vehicle lower part structure which concerns on embodiment of this invention. It is the side view seen from the vehicle left side which shows the principal part of the vehicle in embodiment of this invention. It is sectional drawing seen from the vehicle left side which shows the principal part of the vehicle lower part structure which concerns on embodiment of this invention. 4 is a graph schematically showing a relationship between a deformation stroke of a vehicle and a load generated by a front cross member and a rear cross member at the time of a vehicle side collision of the vehicle lower structure according to the embodiment of the present invention. 4 is a graph showing in detail a relationship between a deformation stroke of a vehicle and a load generated by a front cross member and a rear cross member at the time of a vehicle side collision of the vehicle lower structure according to the embodiment of the present invention.

Explanation of symbols

10 Vehicle Lower Structure 12 Vehicle 16 Floor 24 Front Floor Panel (First Floor)
28 Center floor panel (2nd floor)
30 Step 36 Front cross member (cross member)
40 Rear cross member (cross member)
46 Fuel tank
48 Rocker 50 Outer reinforcement (load transmission means)
52 Bulk (load transmission means)

Claims (3)

A first floor constituting a floor of the vehicle;
Constituting the floor, a second floor disposed on the vehicle upper side of the first floor;
A pair of cross members that are formed in a closed cross-section at the step between the first floor and the second floor and that extend in the vehicle width direction and are displaced in the vehicle longitudinal direction;
Vehicle lower structure equipped with. A rocker that is disposed outside the floor in the vehicle width direction and extends in the vehicle longitudinal direction;
Load transmitting means for transmitting the load input to the rocker to the pair of cross members;
The vehicle lower structure according to claim 1, further comprising:   The vehicle rear side cross member is disposed on the vehicle upper side of the cross member on the vehicle front side, and a tank is disposed on the vehicle lower side of the cross member on the vehicle rear side. Item 2. The vehicle lower structure according to Item 2.

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