Underfloor Protector Structure for Side-Collision Load Redirection

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Solution Overview

Problem

Conventional vehicle structures fail to adequately protect underfloor components like high-voltage components or fuel tanks during side collisions, as impact loads are transmitted through the boarding and alighting step, leading to insufficient protection.

Innovation Solution

A protector structure with a boarding and alighting step and a protection member featuring an inclined contact wall that redirects impact forces, allowing the step to rotate and detach preferentially at a brittle second attachment point, dispersing loads through reinforcing members to an underfloor frame, thereby preventing direct impact on the underfloor component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a boarding and alighting step is disposed laterally outward with respect to an underfloor component, then ease of operation for boarding and alighting is improved, but protection of the underfloor component during side collision deteriorates due to impact load transmission

Engineering Contradiction:

Improveboarding and alighting convenienceVSAvoidunderfloor component protection during side collision

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

A protection member is introduced as an intermediary component disposed between the boarding and alighting step and the underfloor component. This mediator receives impact loads from the step during side collisions and redirects them downward through its inclined contact wall, preventing direct transmission of lateral impact forces to the underfloor component while allowing the step to remain in its operational position.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The contact wall of the protection member is designed with a specific inclination angle relative to the lateral direction. This parameter change transforms the direction of impact forces from horizontal (lateral) to vertical (downward), effectively redirecting the collision loads away from the underfloor component and into the ground through the step structure.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the protection member includes an inclined contact wall to redirect impact forces, then underfloor component protection is improved, but device complexity increases due to additional structural elements

Engineering Contradiction:

Improveunderfloor component protectionVSAvoidprotection member structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protection member is designed to perform multiple functions simultaneously: it acts as an impact load receiver during side collisions, serves as a structural support element, and provides a mounting interface for the boarding and alighting step. This multi-functionality reduces the need for separate dedicated protection structures, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The protection member is integrated with the existing boarding and alighting step structure rather than being a completely separate component. The contact wall is merged with the step's support structure, and attachment portions are combined, allowing the protection function to be achieved while minimizing additional parts and simplifying the overall assembly.

Inventive Principle:

Principle #5Merging (Combining)

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

Effectively prevents direct or indirect impact on underfloor components by redirecting and dispersing collision forces, ensuring reliable protection during side collisions.

Implementation Method 1

the boarding and alighting step impacting against the contact wall in a side collision to receive a downward reaction force from the contact wall

Methodology Applied

Scientific EffectImpact force: Impact Force

Implementation Method 2

This further causes the boarding and alighting step to rotate in such a manner that the laterally inward end moves downward

Methodology Applied

Scientific EffectRotation:

Implementation Method 3

a brittle part that is likely to rupture or deform due to a stress locally concentrated on the brittle part by application of a downward force

Methodology Applied

Scientific EffectStress concentration:

Implementation Method 4

a brittle part that is likely to rupture or deform due to a stress locally concentrated on the brittle part

Methodology Applied

Scientific EffectFracture: Fracture Mechanics

Data Source

PatentUS12528543B2Protector structure for underfloor component

Publication Date: 2026.01.20 TOYOTA JIDOSHA KK

AI summary

A protector structure for an underfloor component includes an underfloor component that is a high-voltage component or a fuel tank disposed under a floor of a vehicle, a boarding and alighting step disposed further laterally outward with respect to the underfloor component, and a protection member disposed between the underfloor component and the boarding and alighting step. The protection member includes a contact wall that laterally faces the boarding and alighting step and that is inclined laterally inward as the contact wall extends downward.