Vehicle Body Lower Structure Impact Protection
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Solution Overview
Problem
Existing vehicle body lower structures face challenges in protecting electric power converters from impact loads without increasing vehicle weight or reducing space under the floor panel, as they require a large cross-sectional area of the side sill, limiting part layout and increasing weight.
Innovation Solution
A vehicle body lower structure design featuring first and second cross members with an electric power converter positioned between them, supported by first and second support portions, where one support portion has a weak portion that can deform or break under impact, distributing the load and preventing concentration on the converter, thus allowing relative displacement and protection without excessive side sill reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cross-sectional area of the side sill is increased to support impact load, then the electric power converter can be protected from impact load, but the weight of the vehicle increases
Solution Approach 1:
The support structure is segmented into multiple cross members (first cross member, second cross member, third cross member) positioned at different locations. This distributes the impact load across multiple points rather than requiring a single large side sill, thereby reducing overall material usage and vehicle weight while maintaining protection effectiveness.
Solution Approach 2:
The electric power converter is provided with localized support portions (first support portion, second support portion, third support portion) that directly engage with the cross members. This concentrates support functionality at specific locations where impact loads are most critical, rather than uniformly reinforcing the entire side sill structure.
2Reliability
If the cross-sectional area of the side sill is increased to support impact load, then the electric power converter can be protected from impact load, but the space below the floor panel is reduced and layout of vehicle parts is limited
Solution Approach 1:
By dividing the support function into multiple discrete cross members positioned at specific intervals, the design avoids the need for a continuously reinforced side sill. This segmentation preserves vertical clearance and horizontal space in the underfloor region, allowing flexible placement of the electric power converter and other components.
Solution Approach 2:
The support structure utilizes the longitudinal dimension by positioning cross members at different forward-backward locations (first, second, and third cross members). This distributes the protective function along the length of the vehicle rather than requiring increased cross-sectional area, thereby preserving vertical and lateral space below the floor panel.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively protects the electric power converter and wire harness by distributing impact loads, reduces the need for large side sill cross-sectional area, minimizing vehicle weight, and enhances space under the floor panel for more flexible part layout and improved ride comfort.
Implementation Method 1
one of the first support portion and the second support portion has a weak portion. Therefore, the weak portion can be deformed or broken by an impact load input from a side surface of a vehicle
Data Source
AI summary
Disclosed is a vehicle body lower structure which is capable of suppressing an increase in a vehicle weight, ensuring a degree of freedom of a layout of vehicle parts and also protecting an electric power converter. In the vehicle body lower structure, the electric power converter is provided between a first cross member and a second cross member. The electric power converter includes an electric power converter body, a first support portion and a second support portion. The electric power converter is disposed between the first cross member and the second cross member. The first support portion is provided at the electric power converter body and supported by the first cross member. The second support portion is provided at the electric power converter body and supported by the second cross member. The second support portion has a weak portion which is deformable by an impact load.