Front Subframe Offset Neutral Axis Small Overlap Collision
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Solution Overview
Problem
Existing front subframe structures face challenges in enhancing collision performance by suppressing bending deformation during small overlap collisions while maintaining sufficient rigidity and accommodating auxiliary components like radiators, which often increase vehicle overhang dimensions.
Innovation Solution
A front subframe structure with a rear cross member, side members, and a front cross member that includes a lateral widening portion and a front widening portion, where the front cross member's neutral axis is offset forward to prevent obstruction of side member bending and allows for flexible auxiliary component placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the front cross member is positioned forward to secure mounting space for auxiliary components, then the mounting space for auxiliary components is improved, but the overhang dimension increases
Solution Approach 1:
The front cross member is designed with an asymmetric configuration where the neutral axis is offset forward relative to the side members. This dimensional repositioning allows the main body of the front cross member to extend forward for mounting auxiliary components while the offset neutral axis prevents obstruction of side member bending, thus resolving the contradiction between mounting space and overhang dimension
Solution Approach 2:
The front cross member features localized structural variations including a forward offset neutral axis and potentially different section properties at different locations. This allows the front portion to provide mounting space while the offset neutral axis region specifically prevents obstruction of collision deformation, addressing different requirements at different locations of the same component
2Reliability
If the front cross member is positioned forward to prevent obstruction of side member bending, then the collision performance is improved, but the mounting space for auxiliary components is reduced
Solution Approach 1:
By offsetting the neutral axis forward rather than simply moving the entire front cross member forward, the invention creates a staggered configuration where the neutral axis (critical for collision performance) is positioned to allow side member bending, while the main body extends forward to provide mounting space, thus resolving the contradiction between collision performance and mounting space
3Device complexity
If the front subframe structure is simplified without a front cross member, then the device complexity is reduced, but the rigidity is insufficient and vibration occurs
Solution Approach 1:
The front cross member is designed to serve multiple functions simultaneously: it provides structural rigidity to prevent vibration, acts as a mounting platform for auxiliary components like radiators, and with its offset neutral axis configuration, allows proper collision deformation of side members. This multi-functionality reduces the need for additional separate components, resolving the contradiction between complexity and rigidity
Data Source
AI summary
A front subframe structure includes front and rear cross members, a pair of left and right side members, and a vehicle body mounting portion disposed on front ends of the side members. The side member has a lateral widening portion at a front end thereof, wherein the lateral widening portion bulges outward in a vehicle width direction. The front cross member has a front widening portion at an end portion thereof in the vehicle width direction, wherein the front widening portion bulges forward of the vehicle. A portion of the front cross member excluding the front widening portion is disposed on the rear side with respect to the vehicle body mounting portion, and on the front side with respect to a rear end of the lateral widening portion.