Expanded Polymer Trim Panel Reinforcement for Impact-Prone Cut Zones

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Solution Overview

Problem

Motor vehicle trim panels made of expanded polymer material face challenges in maintaining mechanical strength, particularly during impacts, due to the risk of breaking at cutting zones when using overmolding techniques with separate reinforcing inserts.

Innovation Solution

Incorporating multiple distinct reinforcing inserts covered with expanded polymer material and connecting them with mechanical elements on an external, invisible face to enhance mechanical strength, specifically at areas prone to rupture during impacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If separate reinforcing inserts are used in overmolding to reduce panel mass, then weight is reduced, but mechanical strength deteriorates at cutting zones

Engineering Contradiction:
Improvepanel massVSAvoidmechanical strength at cutting zones
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The panel is divided into multiple separate reinforcing inserts instead of using a single continuous insert. This segmentation allows weight reduction while maintaining strength through strategic placement and connection of individual inserts, resolving the contradiction between reduced mass and maintained mechanical strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Mechanical connecting elements are introduced as intermediaries to join the separate reinforcing inserts. These connectors bridge the gaps between inserts, transferring loads and preventing rupture at the cutting zones, thus maintaining mechanical strength despite the segmented structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Weight of moving object

If multiple separate reinforcing inserts are used, then weight is reduced, but panel reliability deteriorates due to rupture risk

Engineering Contradiction:
Improvepanel massVSAvoidpanel resistance to impact
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

Mechanical connecting elements serve as intermediaries that link separate reinforcing inserts, ensuring load transfer and preventing rupture propagation between inserts. This maintains panel reliability under impact conditions while preserving the weight benefits of segmentation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The panel combines expanded polymer material with traditional reinforcing inserts and mechanical connectors, creating a composite structure that leverages the lightweight properties of expanded polymer while maintaining the structural integrity provided by metal inserts and connectors.

Inventive Principle:
Principle #40Composite materials

3Strength

If mechanical connecting elements are added to connect reinforcing inserts, then mechanical strength is improved, but device complexity increases

Engineering Contradiction:
Improvemechanical strength at insert connectionsVSAvoidpanel structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

Mechanical connecting elements are applied only at specific locations where reinforcing inserts require connection, rather than throughout the entire panel. This localized approach provides necessary strength enhancement while minimizing the increase in overall device complexity.

Inventive Principle:
Principle #3Local quality

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

The solution provides enhanced mechanical strength and resistance to impacts while maintaining a lightweight structure, ensuring the panel's integrity and visual appearance remains unaffected.

Implementation Method 1

Expanded polymer material refers to a cellular material consisting of a solid polymer phase and a dispersed gas phase

Methodology Applied
Scientific EffectCellular material structure: Foam

Implementation Method 2

The panel is then produced by overmolding the expanded polymer material onto the reinforcement insert

Methodology Applied
Scientific EffectOvermolding:

Data Source

PatentEP4031416B1Motor vehicle trim panel made of expanded polymer material
Publication Date: 2024.07.31 RENAULT SA
  • EP4031416B1 patent drawingFigure 1~2
  • EP4031416B1 patent drawingFigure 3~4

AI summary

The invention relates to a motor vehicle trim panel made of expanded polymer material, characterized in that it comprises a plurality of distinct reinforcement inserts (11-15) covered with an expanded polymeric material and in that at least one reinforcement insert is connected to an adjacent reinforcement insert by means of a mechanical connecting element (21- 25) applied to an outer face of the trim panel.