Vehicle Lower Section Structure Offset Collision Load Transmission

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Solution Overview

Problem

Existing vehicle lower section structures are inadequate in preventing deformation of the vehicle body frame during offset collisions and do not efficiently secure space for power supply components like batteries at the vehicle's lower side.

Innovation Solution

A vehicle lower section structure featuring a monocoque floor panel with inflected side members that spread outward, a crossing section for load transmission, and a torque box to disperse collision loads, along with a reinforcement section inside the battery case to support deformation and secure the battery pack.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the side member rear is provided with an inflected portion spreading out toward the vehicle width direction outward, then the space for power supply section is increased, but the side member becomes more prone to deformation under collision load

Engineering Contradiction:

Improvespace for power supply sectionVSAvoidresistance to collision load

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The side member rear is configured with an inflected portion that spreads out in the vehicle width direction, utilizing the lateral dimension to create additional space for the power supply section while maintaining structural integrity through the inflection geometry

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The side member is constructed as a composite structure combining the side member front and side member rear with different geometric configurations, where the inflected portion creates a composite cross-sectional shape that provides both space and structural resistance to deformation

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If the floor frames extend straight along the vehicle front-rear direction, then the manufacturing is simplified, but stress concentrates at connection portions during offset collision causing folding deformation

Engineering Contradiction:

Improveframe fabrication simplicityVSAvoidresistance to folding deformation

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The side member rear is designed with a curved inflected portion that spreads outward, replacing a straight linear configuration with a curved geometry that distributes stress more effectively during offset collision while maintaining manufacturing feasibility

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Strength

If the crossing section is disposed between the inflected portions, then load transmission between side members is improved, but the structural complexity is increased

Engineering Contradiction:

Improveload transmission capabilityVSAvoidframe structure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The crossing section acts as an intermediary element disposed between the inflected portions of the side members, providing a dedicated load transmission path that connects the left and right side members during offset collision while maintaining clear separation of structural functions

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP3318471B1Vehicle lower section structure

Publication Date: 2020.05.06 TOYOTA JIDOSHA KK

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AI summary

A crossing member (32) disposed along a vehicle width direction between inflected portions of side members (28) is capable of transmitting load from one of the side members (28) to the other of the side members (28) when the one side member (28) deforms toward a vehicle width direction inward. Accordingly, when collision load is input due to an offset collision or the like, the collision load is transmitted from the one side member (28) input with the collision load to the other side member (28) through the crossing member (32), and the collision load is supported by the other side member (28).