JP2019123272A - Vehicular lower structure - Google Patents

Abstract

To alleviate an impact by effectively absorbing the energy of a lateral crash.SOLUTION: A vehicular lower structure 100 includes a pair of side members 26 disposed in a vehicle width direction with a space between them and extended in a vehicular fore-and-aft direction, and a cross member 22 that extends in the vehicle width direction and connects the pair of side members 26. The cross member 22 has a pair of cross member low-intensity parts 22a, the intensity of which is lower than that of a center part, at both ends in the vehicle width direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle undercarriage, and in particular to measures against side collisions.

  Patent Document 1 discloses that a battery storage area is formed by a floor upper case forming a floor of a vehicle and a floor lower case, and a battery is mounted under the floor. The rigidity of the floor upper case and the floor lower case is held by a side frame which is a framework structure in the front-rear direction of the vehicle and a cross member which is a framework structure in the vehicle width direction.

JP, 2014-201277, A

  By maintaining the rigidity by the cross member, the deformation of the vehicle lower structure can be reduced against the side impact, and the influence on the battery can be reduced. Here, in this configuration, the rigidity against the impact from the side of the vehicle can be increased, but the absorption of the collision energy is small, and there is room for improvement in this point.

  The present invention provides a vehicle undercarriage capable of absorbing collision energy more effectively.

  The present invention is a vehicle lower structure, which is disposed at an interval in the vehicle width direction, and which extends in the vehicle longitudinal direction, a battery disposed between the pair of side members, and a vehicle The cross member has a pair of cross member low strength portions having lower strength than the central portion at both end sides in the vehicle width direction, and includes a cross member extending in the width direction of and connecting the pair of side members.

  Further, the pair of cross member low strength portions may be positioned outside the battery in the vehicle width direction.

  Furthermore, the outer portion of the pair of cross member low strength portions may be bolted to the pair of side members.

  Furthermore, the pair of cross member low strength portions may be configured separately from the central portion of the cross member, and the inner portion may be fixed to both ends of the central portion of the cross member.

  Furthermore, the pair of cross member low strength portions may be fixed by welding to the central portion of the cross member.

  Furthermore, the cross member may be located below the battery, and may be fixed to the pair of side members on both sides of the battery.

  According to the present invention, it is possible to absorb energy at the time of a collision from the side, effectively cushion the impact, and protect the battery and the like.

It is a perspective view showing the vehicle lower part structure concerning an embodiment. FIG. 2 is a schematic view of the vehicle lower structure according to the embodiment as viewed from the rear. It is a perspective view which shows the state which attached the seat bracket to the floor cloth. It is the schematic diagram which looked at the battery mounting part of the vehicle lower part structure which concerns on embodiment from the bottom.

  Hereinafter, embodiments of the present invention will be described based on the drawings. The present invention is not limited to the embodiments described herein.

  FIG. 1 is a perspective view showing a vehicle lower structure 100 according to the embodiment. At a central portion in the vehicle width direction of the floor panel 10, a floor tunnel 12 extending in the longitudinal direction of the vehicle is provided. In the floor tunnel 12, a part of the floor panel 10 is formed to be raised upward, and the inside becomes a space for accommodating various members.

  A rocker 14 extending in the longitudinal direction of the vehicle is disposed on the left and right sides (both sides in the vehicle width direction) of the floor panel 10. The rocker 14 is a pipe-shaped member having a square cross-sectional shape, which is configured by joining two long plate materials having a C-shaped cross section so that the recesses face each other. The rocker 14 is a frame member of a vehicle and has relatively high strength.

  A floor cross 16 extending in the vehicle width direction is provided on the floor panel 10. The floor cross 16 is a frame member of the vehicle and resists lateral forces. The left and right ends of the floor cross 16 are fixed to the side wall of the rocker 14. Thus, the vehicle compartment can be protected from the front-rear direction and the left-right direction by the pair of rockers 14 and the floor cross 16. The floor cross 16 is C-shaped in cross section and fixed on the floor panel 10 with the recess facing downward.

  Further, on the floor panel 10, a pair of kicks 18 extending in the front-rear direction is disposed. The kick 18 is fixed from above to the floor panel 10 with the recess facing downward with a C-shaped cross section. Further, they are disposed on the inner side of the pair of rockers 14, and the front side is curved inward and curved toward the center side, and the rear side is positioned near the rockers 14 (both sides in the vehicle width direction).

  A battery 20 is disposed inside the kick 18 and in the lower area of the floor panel 10. That is, the battery 20 is disposed between the pair of rockers 14 and between the pair of kicks 18. In addition, the floor cross 16 is located above the battery 20. Accordingly, the floor cross 16 also functions as a protection member for the battery 20 in the vehicle width direction.

  A cross member 22 extending in the vehicle width direction is disposed below the battery 20, and the cross member 22 supports the battery 20 from below. The cross member 22 is in the form of a long plate, and both ends thereof are fixed to the side members 26. Cross member 22 is a member having high strength, and functions as a protection member that protects battery 20 from an impact in the vehicle width direction.

  Here, in the present embodiment, the floor cloth low strength portion 16 a is provided at the joint portion of the floor cloth 16 with the rocker 14. The floor cross low strength portion 16 a has a lower strength (for example, shear allowable stress strength) than the central portion 16 b of the floor cross 16. For example, it is preferable to set the strength to about half that of the central portion 16b.

  In the present embodiment, the floor cloth low strength portion 16a is configured as a separate member from the central portion 16b. Therefore, it is possible to easily adjust the strength by changing the material or changing the thickness. The floor cloth low-strength portion 16a can also be formed by changing the thickness, changing the cross-sectional area, or making a cut, without necessarily forming a separate member. In the case of using a separate member, the floor cloth low strength portion 16a is joined to the central portion 16b by an appropriate means such as welding.

  The floor cloth low-strength portion 16a is basically a C-shaped member having a C-shaped cross section open at the lower side, and there are portions extending in the form of flanges on both sides in the front-rear direction. It is joined to 18a. In addition, a flange-like edge is also formed on a portion that abuts on the side surface of the rocker 14 and is joined to the side surface of the rocker 14 here. The upper surface of the floor cloth low strength portion 16 a has a laterally extending extension portion, and this portion is superimposed on the upper surface of the rocker 14. Thus, this extension can be fixed to the upper surface of the rocker 14. For these connections, appropriate means such as welding can be adopted as described above.

  In addition, cross member low strength portions 22 a are provided in connection portions with the side members 26 at both ends of the cross member 22. The strength of the cross member low strength portion 22 a is smaller than that of the central portion 22 b of the cross member 22. Similar to the floor cross low strength portion 16a, it may be configured separately from the central portion 22b, but may be formed as a part of the cross member 22, and the adjustment of strength is also performed in the same manner as the floor cross low strength portion 16a. Can.

  The cross member low strength portion 22 a is bolted to the side member 26 via the collar 24. That is, the side member 26 is located on the rear side of the kick 18 and above the cross member low strength portion 22 a and below the fastening portion 18 a with the floor panel 10 interposed therebetween. Thus, the side members 26 and the cross member low strength portion 22 a are fastened by bolts passing through the collar 24.

  The structure which looked at the floor cross 16, the cross member 22, the rocker 14, and the kick 18 from the back is typically shown by FIG. In particular, the junction between the cross member low strength portion 22 a and the side member 26 is specified. The cross member low strength portion 22 a is plate-like like the cross member 22, and one end (inner end) is joined (eg, welded) to the end of the cross member 22. The cross member low strength portion 22a has an inclined portion at the middle in the vehicle width direction, with the outer side at a high position and the inner side at a low position. Then, the inner portion of the cross member low strength portion 22 a is joined to the end of the cross member 22 from the lower side.

  The side member 26 is a member having a C-shaped cross section whose upper side opens, and the flange portion (edge portion) of the upper surface is joined to the flange portion of the kick 18. The lower surface of the side member 26 is opposed to the cross member low strength portion 22a, and the hollow cylindrical collar 24 is disposed here, and the bolt 28 passing through the cross member low strength portion 22a, the collar 24 and the side member 26 is used. The cross member low strength portion 22 a is fixed to the side member 26 by screwing a nut 30 to the tip end of the bolt 28.

  Here, both ends of the central portion 16 b of the floor cross 16 and the central portion 22 b of the cross member 22 extend to the outside of the battery 20 in the vehicle width direction. In other words, the positions at which the strengths of the floor cross low strength portion 16a and the cross member low strength portion 22a begin to weaken are outside the battery 20 in the vehicle width direction. Therefore, the battery 20 can be protected by the central portion 16 b of the high strength floor cloth 16 and the central portion 22 b of the cross member 22.

  The structure of the floor cloth 16 is shown in FIG. A seat bracket 32 is fixed to the floor cross 16 for fixing a seat on which the occupant sits. The seat bracket 32 is a box-like member having a quadrangular pyramidal outer shape, and the flange portion (edge) of the bottom is fixed to the upper surface and the side surface of the floor cross 16 by welding or the like. Then, the seat (seat rail) is fixed to the upper surface of the seat bracket 32. The seat bracket 32 has lower strength than the central portion 16 b of the floor cross 16.

  Here, in the present embodiment, the seat bracket 32 on the outer side in the vehicle width direction indicated by the two-dot chain line is attached to the floor cloth low strength portion 16a. By this, when a force is applied to the floor cloth low strength portion 16a, the force is also transmitted to the seat bracket 32, and the box-like seat bracket 32 is crushed, and the impact is effectively absorbed also in this portion.

  As described above, in the vehicle lower structure according to the present embodiment, the floor cloth low strength portion 16 a is provided at the connection portion between the floor cross 16 and the rocker 14. Further, a cross member low strength portion 22 a is provided at the connection portion between the cross member 22 and the kick 18. For this reason, at the time of a collision with the vehicle side, when receiving a strong force from the vehicle side toward the inside, the floor cross low strength portion 16a and the cross member low strength portion 22a are deformed to absorb the impact force. Therefore, the acceleration of the battery 20 in the event of a collision can be reduced, and the battery 20 can be effectively protected. In addition, the acceleration of the passenger compartment can be reduced, and the protection performance for occupants and other devices in the passenger compartment can be improved.

  Further, as shown in FIG. 3, by providing the seat bracket 32 in the floor cloth low strength portion 16a, energy absorption due to the deformation of the seat bracket 32 also occurs, and the total energy absorption amount can be increased.

  FIG. 4 is a bottom view of the battery 20 mounting portion of the vehicle lower structure. In this example, the batteries 20 are arranged in a plurality of rows in the longitudinal direction of the vehicle, and occupy a relatively large area. Four cross members 22 are arranged at intervals in the vehicle longitudinal direction. Then, cross member low strength portions 22 a are provided at both ends of each cross member 22, and the floor cross low strength portions 16 a are respectively fixed to the side members 26.

  In addition, a reinforcing member 34 is provided to connect the plurality of cross members 22 in the vehicle longitudinal direction. In this example, two reinforcing members 34 connecting the three cross members 22 are provided, and one reinforcing member 34 connecting the four cross members 22 is provided in the middle thereof. Such a configuration can effectively protect the battery 20.

  In addition, the vehicle frame member for securing the rigidity of a vehicle needs to endure a big impact, and usually steel materials are adopted. In addition, metal materials are also suitable for members that deform and absorb energy.

Reference Signs List 10 floor panel, 12 floor tunnel, 14 rocker, 16 floor cloth, 16a floor cloth low strength portion, 16b central portion, 18 kick, 18a fastening portion, 20 battery, 22 cross member, 22a cross member low strength portion, 22b central portion , 24 collars, 26 side members, 28 bolts, 30 nuts, 32 seat brackets, 34 reinforcing members, 100 vehicle undercarriage.

Claims (6)

Vehicle substructure,
A pair of side members arranged at intervals in the vehicle width direction and extending in the vehicle longitudinal direction;
A battery disposed between the pair of side members;
A cross member extending in the width direction of the vehicle and connecting the pair of side members;
Including
The cross member has a pair of cross member low strength portions having lower strength than the central portion at both end sides in the vehicle width direction.
Vehicle substructure. A vehicle under structure according to claim 1, wherein
The pair of cross member low strength portions are located outside the battery in the vehicle width direction,
Vehicle substructure. A vehicle under structure according to claim 1 or 2, wherein
In the pair of cross member low strength portions, the outer side portion is bolted to the pair of side members,
Vehicle substructure. The vehicle under structure according to any one of claims 1 to 3, wherein
The pair of cross member low strength portions are formed separately from the central portion of the cross member, and the inner portion is fixed to both ends of the central portion of the cross member.
Vehicle substructure. A vehicle under structure according to claim 4, wherein
The pair of cross member low strength portions has an inner portion fixed by welding to a central portion of the cross member.
Vehicle substructure. The vehicle under structure according to any one of claims 1 to 5, wherein
The cross member is located below the battery and is fixed to the pair of side members on both sides of the battery.
Vehicle substructure.