Vehicle Front Cross Member Weak Portion for Early Wheel Detachment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle front portion structures fail to effectively detach the front wheel from the lower arm at an early stage during a small overlap crash, which can lead to the front wheel approaching the cabin and compromising crash safety.
Innovation Solution
A vehicle front portion structure is designed with a suspension member and a weak portion in the front cross member that is specifically configured to break under load, allowing the front wheel to detach from the lower arm by creating a toe-out effect and promoting the breaking of the weak portion, such as a recessed bead, open, cutout, or reduced coupling strength, to facilitate early detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lower arm is coupled to the front side coupling portion without a weak portion, then the front wheel remains firmly attached to the lower arm, but the front wheel cannot detach early during a small overlap crash, causing it to approach the cabin and compromising safety
Solution Approach 1:
The front cross member is segmented into a weak portion and strong portion, allowing controlled detachment at the weak portion while maintaining connection at the strong portion. This segmentation enables the front wheel to detach from the lower arm during crash while preserving structural integrity elsewhere.
Solution Approach 2:
Different portions of the front cross member have different structural qualities - the weak portion is designed with lower strength to detach early, while the strong portion maintains high strength for overall structural support. This local quality differentiation resolves the contradiction between firm attachment and controlled detachment.
2Ease of operation
If a weak portion is formed in the front cross member, then the front wheel can detach early from the lower arm during crash, but the structural strength of the front cross member is reduced
Solution Approach 1:
The front cross member is divided into weak and strong portions, allowing the weak portion to detach easily while the strong portion maintains structural strength. This segmentation enables both easy detachment and sufficient strength to coexist.
Solution Approach 2:
The front cross member exhibits local quality variation with a weak portion for easy detachment and a strong portion for structural support. This local differentiation resolves the contradiction between detachment ease and overall strength.
3Stability of the object's composition
If the weak portion is formed on the vehicle width direction inside of the coupling point, then toe out is suppressed and the rear end portion of the front wheel collides with the rocker, but the load transmission path changes affecting detachment mechanics
Solution Approach 1:
The weak portion is positioned to extract or redirect the load transmission path, causing toe out suppression and directing the rear end portion of the front wheel to collide with the rocker. This extraction of the load path achieves position stability while managing the complexity through controlled load redirection.
Data Source
AI summary
There is provided a vehicle front portion structure including (1) a suspension member having (i) a front cross member and a rear cross member, and (ii) a side rail that couples vehicle width direction outside end portions of the front cross member and the rear cross member, (2) a lower arm whose vehicle width direction outside end portion is coupled to a front wheel and whose vehicle width direction inside end portion is coupled at least to a front side coupling portion and a rear side coupling portion of the suspension member, and (3) a weak portion that is formed in the front cross member on the vehicle width direction inside of a coupling point at which the lower arm and the front side coupling portion are coupled to each other and that is to be broken by a load input from the vehicle body front side.