Rear Pillar Reinforcement Layout for Frontal Impact Retaining Loads

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Solution Overview

Problem

Existing vehicle structures fail to adequately strengthen the rear lateral structure against significant tensile forces directed towards the front of the vehicle during a frontal collision, particularly from restraint systems like seat belt retractors and seat back locking mechanisms, while maintaining weight reduction for environmental sustainability.

Innovation Solution

A reinforcement with two lateral wings is fixed to the rear pillar liner and rear wheel arch, positioned at the same height as the restraint system brackets, transmitting forces to the rear wheel arch to reduce stress on the rear pillar liner and maintain safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the vehicle body mass is reduced to decrease greenhouse gas emissions, then fuel efficiency is improved, but the strength and safety of the rear pillar liner deteriorates when subjected to tensile forces from restraint systems during frontal collision

Engineering Contradiction:
Improvevehicle body massVSAvoidrear pillar liner strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

A reinforcement component is introduced as an intermediary element between the rear pillar liner and the rear wheel arch. This reinforcement component has a first lateral wing fixed to the rear pillar liner and a second lateral wing fixed to the rear wheel arch, creating a force transmission path that relieves the rear pillar liner from bearing the full tensile load during frontal collision, thus maintaining strength while allowing body mass reduction

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The reinforcement component extends in the transverse direction of the vehicle, connecting the rear pillar liner to the rear wheel arch laterally. This dimensional approach distributes the tensile forces across a broader structural framework rather than concentrating them vertically in the rear pillar liner, enabling weight reduction without compromising collision resistance

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If the rear pillar liner is made stronger to withstand tensile forces from restraint systems, then safety is improved, but the vehicle body mass increases

Engineering Contradiction:
Improverear pillar liner strengthVSAvoidvehicle body mass
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The force-bearing function is segmented between two components: the rear pillar liner and the reinforcement component. The reinforcement component specifically handles the tensile forces from restraint systems during frontal collision, allowing the rear pillar liner to be optimized for other structural functions, thereby reducing overall body mass while maintaining safety

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reinforcement component acts as a mediator that transfers tensile forces from the restraint system mounting area to the rear wheel arch, preventing these forces from being fully transmitted to the rear pillar liner. This enables the rear pillar liner to be lighter while the reinforcement component compensates for the reduced strength

Inventive Principle:
Principle #24Intermediary (Mediator)

3Force

If the reinforcement is positioned at the same height as the restraint system brackets, then force transmission efficiency is improved, but the complexity of structural design increases

Engineering Contradiction:
Improveforce transmission efficiencyVSAvoidstructural design complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The reinforcement component is positioned at a specific location (same height as restraint system brackets) with specific local properties (lateral wings extending to connect rear pillar liner and rear wheel arch). This localized optimization ensures efficient force transmission at the critical mounting area without requiring complex modifications throughout the entire vehicle structure, balancing performance improvement with design complexity

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3898385B1Vehicle with reinforced structure for limiting retaining forces in the event of a frontal impact
Publication Date: 2025.11.12 STELLANTIS AUTO SAS
  • EP3898385B1 patent drawingFigure 1~2
  • EP3898385B1 patent drawingFigure 3~4
  • EP3898385B1 patent drawingFigure 5

AI summary

The invention relates to a motor vehicle comprising a rear pillar liner (3) and a rear wheelhouse (5), and at least one retaining system support (7) fastened to the rear pillar liner (3), the vehicle being noteworthy in that it additionally comprises a reinforcement (9) featuring two lateral wings, said reinforcement (9) being fastened by its lateral wings to the rear pillar liner (3) and to the rear wheelhouse (5), and in that said reinforcement (9) is arranged on the rear pillar liner (3) at least in part at the same height as the retaining system support(s) (7).