Vehicle Front Cross Member Joint for Pole Collision Load Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle front structures are prone to detachment of the front cross member from the front side frame during pole frontal-collisions due to shearing loads, leading to reduced collision-load absorption performance.
Innovation Solution
A vehicle front structure design where the cross member fits into recess portions of the front side frames, supporting collision loads in the axial direction and preventing detachment, allowing the cross member to deform in a U-shape and draw the frames inward, enhancing collision-load absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cross member is fixed to the front side frame using a conventional joining structure, then the structure is simple to manufacture, but the joining portion may break under shearing loads during pole frontal-collision
Solution Approach 1:
The front side frame is segmented into an inner wall portion and an outer wall portion, with the inner wall portion having a recess portion that receives the cross member. This segmentation allows the collision load to be supported by the inner wall portion in the axial direction, preventing shearing loads at the joining portion while maintaining a relatively simple overall structure.
Solution Approach 2:
The recess portion is designed to extend in the vehicle width direction, creating a three-dimensional receiving space for the cross member. This dimensional change allows the cross member to be supported from multiple directions, distributing the collision load and preventing detachment without requiring complex additional joining mechanisms.
2Reliability
If the cross member is rigidly fixed to prevent detachment, then the collision-load absorption performance is improved, but the cross member cannot deform to absorb energy through controlled deformation
Solution Approach 1:
The joining structure provides dynamic characteristics by allowing the cross member to deform in a controlled manner during collision. The recess portion design enables the cross member to move and deform to absorb energy, while the structure prevents complete detachment. This dynamic behavior optimizes collision-load absorption without requiring excessive rigidity.
Solution Approach 2:
The structural parameters are optimized to balance rigidity and deformability. The recess portion dimensions, depth, and shape are specifically designed to provide sufficient support to prevent detachment while allowing controlled deformation. This parameter optimization enables the structure to transition between rigid and flexible states as needed during collision events.
Data Source
AI summary
A front structure of a vehicle comprises a pair of right-and-left front side frames extending in a longitudinal direction and having a closed-cross section perpendicular to an extension direction thereof, respectively, and a cross member extending in a vehicle width direction between the pair of right-and-left front side frames, wherein each of the front side frames comprises an inner wall portion which is positioned on an inward side, in the vehicle width direction, thereof, the inner wall portion has a recess portion which is configured such that a front edge of the inner wall portion partially retreats rearward, and both-side portions, in the vehicle width direction, of the cross member fit into said respective recess portions of the inner wall portions from a forward side and are fixed to the inner wall portions of the front side frames.