JP2023131276A - Vehicle lower section structure - Google Patents

Abstract

To secure a collision stroke in a vehicle side collision.SOLUTION: A vehicle lower section structure 100 includes: a pair of rockers 10 extending in a vehicle back-and-forth direction at both side parts of a vehicle 60; and a battery pack 30 arranged between the pair of rockers 10. Each rocker 10 includes a collision absorbing part 20 that absorbs collision energy in a vehicle widthwise direction by being collapsed in the vehicle widthwise direction in a side collision of the vehicle 60. The battery pack 30 and each rocker 10 are connected to each other at a lower side than a bottom surface 32a of the battery pack 30 and at a lower side than each lower end surface 14a of each rocker 10.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a structure of a lower part of a vehicle including lockers arranged on both sides of the vehicle and a battery pack arranged between the lockers.

In recent years, electric vehicles have been used that have a battery pack mounted on the lower side of the floor panel. A battery pack installed in such an electric vehicle is installed in the vehicle by bolting a flange or bracket that protrudes outward in the vehicle width direction from the bottom plate of the casing to the bottom surface of rockers located on both sides of the vehicle. (For example, see Patent Documents 1 and 2).

Further, Patent Documents 1 and 2 describe that a shock absorbing portion for absorbing impact energy at the time of a side collision of a vehicle is provided inside the rocker.

JP2019-25935A JP 2019-137354 Publication

In the structures described in Patent Documents 1 and 2, bolts for attaching the battery pack protrude into the interior of the locker from the lower surface of the locker. Since the bolt has high rigidity, it will not be crushed even if the vehicle collides with the side and the shock absorbing part is crushed in the width direction of the vehicle. Therefore, in the event of a side collision, the bolt gets caught between the side collision pole and the battery pack, and the impact absorption part inside the rocker is not crushed by the length of the bolt in the vehicle width direction, and the collision stroke is shortened by that amount. There was a problem with this.

Therefore, an object of the present invention is to ensure a collision stroke in the event of a vehicle side collision.

A vehicle lower structure of the present invention is a vehicle lower structure including a pair of rockers extending in the longitudinal direction of the vehicle on both sides of the vehicle, and a battery pack disposed between the pair of rockers, wherein each of the rockers is , the battery pack and each of the rockers are located below the bottom surface of the battery pack and each of the rockers is provided with a shock absorbing portion that collapses in the vehicle width direction and absorbs impact energy in the vehicle width direction in the event of a side collision of the vehicle; It is characterized by being connected below each lower end surface of.

Since the battery pack and the rocker are connected below the bottom surface of the battery pack and below each lower end surface of the rocker, the bolt will not be caught between the side collision pole and the battery pack in the event of a side collision. . Therefore, the impact absorbing portion of the rocker is sufficiently crushed to ensure a collision stroke in the event of a side collision of the vehicle.

In the vehicle undercarriage structure of the present invention, each of the rockers includes a flange projecting downward from each lower end surface, the battery pack includes a pair of mounting flanges projecting below from the bottom surface, and the battery pack includes: The rocker may be attached to each rocker with at least one bolt fastening each mounting flange to each flange.

Thereby, the battery pack and the rocker can be connected below the bottom surface of the battery pack and below each lower end surface of the rocker, and a collision stroke in the event of a side collision of the vehicle can be secured.

In the vehicle undercarriage structure of the present invention, the battery pack includes a lateral flange extending outward in the vehicle width direction from lower end portions of both ends in the vehicle width direction, and the mounting flange extends from an outer end in the vehicle width direction of the lateral flange. It may extend downward.

By providing the horizontal flange, when attaching the battery pack to the rocker, bolts can be attached with the horizontal flange aligned with the lower end surface of the rocker. This facilitates assembly of the battery pack.

In the vehicle lower structure of the present invention, each of the flanges protrudes below the lower end surface at an inner end in the vehicle width direction of each of the lockers, and the mounting flange is arranged on the bottom surface at both ends of the battery pack in the vehicle width direction. It may also protrude further downward.

By arranging the flange on the inner side of the rocker in the vehicle width direction in this manner, the position of the flange does not overlap with the shock absorbing portion of the rocker when viewed from the top of the vehicle. Therefore, in the event of a side collision, the side collision pole does not interfere with the flange and the mounting flange, and can advance to the inner side of the rocker in the vehicle width direction while crushing the impact absorbing portion. Thereby, a larger collision stroke can be ensured.

In the vehicle lower structure of the present invention, the bolt may fasten each of the mounting flanges to each of the flanges in a direction along a lower end surface of the rocker and the bottom surface of the battery pack.

This prevents a part of the bolt from protruding into the interior of the rocker and being caught between the side impact pole and the battery pack in the event of a side impact, thereby making it possible to secure a collision stroke in the event of a vehicle side impact.

INDUSTRIAL APPLICATION This invention can ensure the collision stroke at the time of a vehicle side collision.

FIG. 1 is a perspective view showing the configuration of a vehicle including a vehicle lower structure according to an embodiment. 2 is a cross-sectional view showing the vehicle lower structure of the embodiment, taken along the line AA shown in FIG. 1. FIG. FIG. 3 is a diagram showing crushing deformation of a rocker when a vehicle including the vehicle lower structure shown in FIG. 2 is involved in a side collision. FIG. 7 is a sectional view showing a vehicle lower structure according to another embodiment.

Hereinafter, a vehicle lower structure 100 according to an embodiment will be described with reference to the drawings. First, a vehicle 60 including a vehicle lower structure 100 according to an embodiment will be described with reference to FIG. Note that arrow FR, arrow UP, and arrow LH shown in each figure indicate the forward direction (progressing direction), upward direction, and left direction of the vehicle 60, respectively. Further, directions opposite to the arrows FR, UP, and LH indicate the rear direction, the downward direction, and the right direction of the vehicle. In the following, when we simply refer to the front-rear, left-right, and up-down directions, unless otherwise specified, we are referring to the front and back of the vehicle's longitudinal direction, the left and right of the vehicle's left-right direction (vehicle width direction), and the top and bottom of the vehicle's vertical direction. do.

As shown in FIG. 1, the vehicle 60 includes a locker 10, floor cross members 26, 27, 28, a floor panel 25, and a battery pack 30.

The locker 10 is a structural member with a closed cross section that is disposed on both left and right sides of the vehicle 60 and extends in the longitudinal direction of the vehicle. The floor panel 25 is a plate member that is spanned between the left and right lockers 10, and constitutes the floor of the vehicle 60. The floor cross members 26, 27, and 28 are structural members with a hat-shaped cross section that are spanned between the pair of left and right rockers 10, and the lower flanges are connected to the upper surface of the floor panel 25 by spot welding. A battery pack 30 is mounted below the floor panel 25.

The battery pack 30 includes a plurality of battery modules 36 and a casing 31 that accommodates the plurality of battery modules 36. The casing 31 includes a peripheral wall 33 that surrounds the periphery, a bottom plate 32, a lid 34, and a cross member 35 that connects the left and right peripheral walls 33. Note that FIG. 1 shows a state with the lid 34 removed. The lid 34 is shown in FIG. Furthermore, lateral flanges 41 extending outward in the vehicle width direction are provided at both ends of the bottom plate 32 of the casing 31 in the vehicle width direction. A mounting flange 42 is provided. The mounting flange 42 is provided with a plurality of bolt holes 43 through which bolts 50 are passed.

Next, with reference to FIG. 2, a detailed structure of the locker 10 and a structure for attaching the battery pack 30 to the locker 10 will be described. In the following description, the structure of the left rocker 10 and the attachment structure between the left end of the battery pack 30 and the left rocker 10 will be described. The structure of the right rocker 10 and the attachment structure between the right end of the battery pack 30 and the right rocker 10 are obtained by horizontally inverting the left side, so a description thereof will be omitted.

As shown in FIG. 2, the rocker 10 includes an outer vertical plate 11, an inner vertical plate 12, a lower plate 14, a lower part 10B with a square closed cross section surrounded by an upper plate 16, and a lower part 10B that stands on the upper plate 16. The upper part 10U is composed of an upper vertical board 13, an upper part of the outer vertical board 11, and a ceiling board 17. An upper flange 15 that protrudes inward in the vehicle width direction is provided on the inner side in the vehicle width direction of the upper plate 16 of the lower portion 10B.

A horizontal plate 21 connecting the outer vertical plate 11 and the inner vertical plate 12 is provided at a position about ⅓ from the bottom of the lower part 10B. Moreover, a plurality of vertical rib plates 22 are provided between the outer vertical plate 11 and the inner vertical plate 12 to connect the horizontal plate 21 and the lower plate 14 in the vertical direction. The horizontal plate 21, the lower plate 14, and the plurality of vertical rib plates 22 constitute a shock absorbing portion 20 of the rocker 10 that absorbs impact energy in the event of a side collision.

The lower end surface 14a of the lower plate 14 is provided with a flange 18 that projects downward from the lower end surface 14a. The flange 18 is a plate member provided on the lower end surface 14a of the rocker 10 and extending in the longitudinal direction of the vehicle, and is provided with a plurality of bolt holes 19 through which the bolts 50 are passed.

For example, the rocker 10 may be formed by extrusion molding of an aluminum alloy.

The peripheral wall 33 of the battery pack 30 is formed by, for example, bending a long extruded product formed by extrusion molding of an aluminum alloy or the like into a rectangular frame shape, and joining the longitudinal ends to each other. As shown in FIG. 1, it has a rectangular frame shape in plan view. As shown in FIG. 2, the peripheral wall 33 has a square closed cross-sectional shape and is provided with horizontal ribs 33a that partition the internal space into upper and lower sections.

A bottom plate 32 constituting the lower end of the battery pack 30 is attached to the lower surface of each of the four sides of the rectangular frame-shaped peripheral wall 33. A lateral flange 41 extending outward in the vehicle width direction is provided at the left end of the bottom plate 32 in the vehicle width direction, and a mounting flange 42 extending downward is provided at the left end of the lateral flange 41. . The mounting flange 42 is provided with a plurality of bolt holes 43 through which bolts 50 are passed.

As shown in FIG. 2, the bolts 50 are inserted through the bolt holes 19 of the flange 18 provided on the lower end surface 14a of the rocker 10 and the bolt holes 43 provided on the mounting flange 42 of the battery pack 30, and the nuts 51 By tightening, the battery pack 30 is attached to the locker 10.

The flange 18 protrudes below the lower end surface 14a of the lower plate 14 of the rocker 10, and the mounting flange 42 protrudes below the bottom surface 32a of the bottom plate 32 of the battery pack 30. Furthermore, each bolt hole 19, 43 is located below the lower end surface 14a and the bottom surface 32a, respectively. Therefore, the battery pack 30 and the locker 10 are connected below the bottom surface 32a of the battery pack 30 and below the lower end surface 14a of the locker 10. Further, the bolts 50 and nuts 51 fasten the mounting flange 42 and the flange 18 in the vehicle width direction, which is a direction along the lower end surface 14a of the rocker 10 and the bottom surface 32a of the battery pack 30.

Next, with reference to FIG. 3, a description will be given of deformation of the rocker 10 when the vehicle 60 including the vehicle lower structure 100 of the embodiment is involved in a side collision. In addition, in FIG. 3, the broken line shows the state before deformation, and the solid line shows the state after deformation.

As shown in FIG. 3, when the side impact pole 90 enters from the left side of the rocker 10 as shown by the arrow 91 in FIG. The left side portion of the shock absorbing portion 20 is collapsed in the vehicle width direction as shown by the solid line in FIG. 3, and is integrated with the outer vertical plate 11 to form a collapsed portion 70. Further, the upper portion 10U of the rocker 10 is also crushed in the vehicle width direction.

Since the bolts 50 are disposed below the bottom surface 32a of the battery pack 30 and below the bottom surface 14a of the rocker 10, the bolts 50 are located below the bottom surface of the battery pack 30 even in the event of a side collision, as shown in FIG. 32a and is located below the lower end surface 14a of the rocker 10. Therefore, the bolt 50 will not be caught between the side impact pole 90 and the battery pack 30 in the event of a side impact. Therefore, the impact absorbing portion 20 disposed in the rocker 10 is sufficiently crushed to ensure the collision stroke L at the time of a side collision of the vehicle.

Further, since the bolt 50 and the nut 51 fasten the mounting flange 42 and the flange 18 in the vehicle width direction, a part of the bolt 50 protrudes into the inside of the rocker 10 in the event of a side collision, and the bolt 50 is prevented from colliding with the side collision. The collision stroke L at the time of a side collision of the vehicle can be secured without being caught between the pole 90 and the battery pack 30.

In the vehicle lower structure 100 of the embodiment, the lateral flange 41 of the battery pack 30 protrudes outward in the vehicle width direction so as to overlap the lower end surface 14a of the lower plate 14 of the rocker 10. The bolt 50 and nut 51 can be attached with the bolt 41 aligned with the lower end surface 14a of the rocker 10. Therefore, the battery pack 30 can be easily assembled.

Next, a vehicle lower structure 200 according to another embodiment will be described with reference to FIG. The same parts as those of the vehicle lower structure 100 previously described with reference to FIGS. 1 to 3 are given the same reference numerals, and the description thereof will be omitted.

In the vehicle lower structure 200 shown in FIG. 4, the flange 18a of the rocker 10 is arranged at the inner end of the rocker 10 in the vehicle width direction, and the mounting flange 42a of the battery pack 30 is arranged at the side end of the bottom plate 32.

As shown in FIG. 4, the flange 18a of the rocker 10 is arranged so as to overlap the inner vertical plate 12 of the rocker 10 when viewed from the top of the vehicle, and the inner surface of the flange 18a in the vehicle width direction overlaps the inner vertical plate 12 of the rocker 10. It is arranged so that it is the same as the inside surface of No. 12 in the vehicle width direction. Therefore, the flange 18a protrudes below the lower end surface 14a at the inner end of the rocker 10 in the vehicle width direction.

Further, the mounting flange 42a is arranged at the side end of the bottom plate 32 so as to overlap the vertical wall 33b of the peripheral wall 33 on the outer side in the vehicle width direction when viewed from the top of the vehicle. Therefore, the mounting flanges 42a protrude below the bottom surface 32a of the bottom plate 32 at both ends of the battery pack 30 in the vehicle width direction.

In this way, by positioning the flange 18a of the rocker 10 and the mounting flange 42a of the battery pack 30 at the inner end of the rocker 10 in the vehicle width direction, the positions of the flange 18a and the mounting flange 42a can be adjusted to reduce the impact of the impact on the rocker 10 when viewed from the top of the vehicle. It does not overlap with the absorption section 20. Therefore, in the event of a side impact, the side impact pole 90 can enter the inner vertical plate 12 of the rocker 10 while crushing the impact absorbing portion 20 without interfering with the flange 18a and the mounting flange 42a. Thereby, a larger collision stroke can be ensured.

10 Rocker, 10B lower part, 10U upper part, 11 outer vertical plate, 12 inner vertical plate, 13 upper vertical plate, 14 lower plate, 14a lower end surface, 15 upper flange, 16 upper plate, 17 ceiling plate, 18, 18a flange, 19 , 43 bolt hole, 20 shock absorber, 21 horizontal plate, 22 vertical rib plate, 25 floor panel, 26, 27, 28 floor cross member, 30 battery pack, 31 casing, 32 bottom plate, 32a bottom surface, 33 peripheral wall, 33a horizontal Rib, 33b vertical wall, 34 lid, 35 cross member, 36 battery module, 41 horizontal flange, 42, 42a mounting flange, 50 bolt, 51 nut, 60 vehicle, 70 crushed portion, 90 side pole, 100, 200 lower vehicle structure.

Claims (5)

a pair of rockers extending in the longitudinal direction of the vehicle on both sides of the vehicle;
A vehicle lower structure including a battery pack disposed between the pair of lockers,
Each of the rockers includes an impact absorption part that collapses in the vehicle width direction and absorbs impact energy in the vehicle width direction when the vehicle is in a side collision,
The battery pack and each locker are connected below the bottom surface of the battery pack and below each lower end surface of each of the lockers;
A vehicle undercarriage structure featuring: The vehicle lower structure according to claim 1,
Each of the rockers includes a flange that protrudes downward from each lower end surface,
The battery pack includes a pair of mounting flanges that protrude downward from the bottom surface,
the battery pack is attached to each of the rockers with at least one bolt fastening each of the mounting flanges to each of the flanges;
A vehicle undercarriage structure featuring: The vehicle lower structure according to claim 2,
The battery pack includes a horizontal flange extending outward in the vehicle width direction from lower end portions of both ends in the vehicle width direction, and the mounting flange extends downward from an outer end in the vehicle width direction of the horizontal flange;
A vehicle undercarriage structure featuring: The vehicle lower structure according to claim 2,
Each of the flanges protrudes below each of the lower end surfaces at an inner end in the vehicle width direction of each of the rockers,
The mounting flanges protrude downward from the bottom surface at both ends of the battery pack in the vehicle width direction;
A vehicle undercarriage structure featuring: The vehicle lower structure according to any one of claims 2 to 4,
The bolts fasten each of the mounting flanges and each of the flanges in a direction along a lower end surface of the rocker and the bottom surface of the battery pack;
A vehicle undercarriage structure featuring: