Vehicle lower body structure

Abstract

Provided is a vehicle lower body structure capable of sufficiently ensuring impact energy absorption performance during a small overlap collision, the vehicle lower body structure being provided with a rocker (2) that forms a first closed cross-section (C1) that extends in the front-rear direction of the vehicle body, and a reinforcing member (30) that is provided within the first closed cross-section (C1) and reinforces the front end portion of the rocker (2). The reinforcing member (30) has: a front end reinforcing section (31) that supports a collision load inputted to the front end portion of the rocker (2) toward the rear of the vehicle body; a deformation permitting section (32) that permits deformation of the rocker (2) toward the inside and the rear in the vehicle width direction when a collision load toward the inside and the rear in the vehicle width direction is input to the front end portion of the rocker (2); and a deformation suppression section (33) that suppresses deformation of the rocker (2) after the rocker (2) deforms inward and rearward in the vehicle width direction.

Description

technical field [0001] The present invention relates to an underbody structure of a vehicle including a side sill having a closed cross section extending in the front-rear direction of the vehicle body and a reinforcing member for reinforcing a front end portion of the side sill. Background technique [0002] Conventionally, it has been known that when an obstacle collides with a part (overlapping area of ​​25% or less) outside the front longitudinal frame in the vehicle width direction represented by the SORB (Small Overlap Rigid Barrier) test, that is, In a so-called small overlap collision, since the front wheels come into contact with the front end of the side sill, the hinge pillar falls toward the rear of the vehicle body. It is also known that when the hinge pillar falls toward the rear of the vehicle body, bending deformation occurs in the rocker due to a moment generated by the collision load concentrated in the rocker. [0003] Therefore, various technical solutio...

AI Technical Summary

Problems solved by technology

[0014] That is, since the bending deformation of the side sill caused by the collision load is structurally suppressed, the inner component in the vehicle width direction of the collision load directly acts on the side sill, causing inversion deformation in which the side sill falls inward in the vehicle width direction.

When the side sill is deformed inwardly, shear stress acts on the joint (flange) formed by welding the outer panel and the inner panel of the side sill, and finally, the joint of the outer panel and the inner panel is cracked. And there is a concern that the section of the side beam will collapse

[0015] When the section of the side sill collapses, the collision load cannot be sufficiently transmitted and distributed to the rear of the vehicle body through the side sill, causing deformation of the cabin

In particular, in a vehicle with an enlarged wheel size, the front-rear length of the wheel house is enlarged, and it is difficult to ensure a crush area for absorbing impact at the front end portion of the side sill. Therefore, compared with a vehicle without an enlarged wheel size, Significant tendency for the side sill to buckle in small overlap collisions

[0016] In other words, there is still room for improvement in impact energy absorption performance in small overlap collisions

Images