Closed-Section Rocker Structure for Side-Impact Energy Absorption
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Solution Overview
Problem
Existing vehicle lower section structures struggle to effectively absorb impact energy and suppress inward folding of the rocker during side collisions, particularly when localized large loads are applied, leading to incomplete crushing and reduced energy absorption.
Innovation Solution
The vehicle lower section structure integrates a pair of rockers with an outer and inner section forming a closed cross-section, incorporating shock absorption sections that are integrally formed with the rocker, allowing for efficient energy absorption by plastic deformation without the need for additional ribs, and dispersing impact loads through multiple transmission routes to the storage battery and floor cross member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a battery side-frame is provided adjacent to the rocker to cancel stress, then deformation of the rocker is suppressed, but in localized large load collisions (e.g., pole collision), the rocker may still fold inward
Solution Approach 1:
The rocker is divided into multiple functional sections: an outer section, an inner section forming a closed cross-section, and a shock absorption section spanning between them. This segmentation allows each section to perform its specific function - the closed cross-section provides structural strength while the shock absorption section handles energy dissipation through controlled deformation.
Solution Approach 2:
The shock absorption section is designed with different material properties or structural parameters compared to the outer and inner sections, enabling it to undergo plastic deformation at lower stress levels. This parameter change allows the shock absorption section to yield first during collision, absorbing energy while protecting the main rocker structure.
2Ease of manufacture
If the outer section and inner section are joined together using welding or fastening, then the rocker can be assembled, but manufacturing complexity and cost increase
Solution Approach 1:
The outer section, inner section, and shock absorption section are merged into a single integrally formed rocker component. This eliminates the need for separate joining operations such as welding or fastening, thereby reducing manufacturing complexity and potential weak points while maintaining structural integrity.
Solution Approach 2:
The integrally formed rocker serves multiple functions simultaneously: providing structural strength through the closed cross-section, absorbing impact energy through the shock absorption section, and eliminating the need for separate joining processes. This multi-functionality is achieved through a single manufacturing operation.
3Loss of energy
If a shock absorption section is added to absorb impact energy, then energy absorption improves, but the structure becomes more complex
Solution Approach 1:
The shock absorption section is merged with the outer and inner sections of the rocker into a single integrally formed component. This integration allows the shock absorption function to be added without requiring separate assemblies or complex joining processes, thereby minimizing the increase in structural complexity.
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 enhances impact energy absorption and suppresses rocker inward folding, reduces the risk of incomplete crushing, and allows for thinner battery packs by distributing load effectively, thereby improving safety and reducing weight.
Implementation Method 1
The first shock absorption section is integrally formed with the outer section and the inner section. The first shock absorption section spans, in the vehicle width direction, between the outer section and the inner section within the closed cross-section section
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
There is provided a vehicle lower section structure including a pair of rockers (14, 16) respectively provided at both vehicle width direction outer sides of a floor panel (12) of a vehicle so as to extend in a vehicle front-rear direction, each of the rockers being configured including: an outer section (22) that is positioned at the vehicle width direction outer side; an inner section (24) that is integrally formed with the outer section, that is positioned at a vehicle width direction inner side, and that forms a closed cross-section section together with the outer section; and a first shock absorption section (38, 40) that is integrally formed with the outer section and the inner section, and that spans in the vehicle width direction between the outer section and the inner section within the closed cross-section section.