Polymeric Trunk Lid Structural Reinforcement for Rigidity

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Solution Overview

Problem

Existing motor vehicle boot lids face issues with insufficient rigidity and aesthetic concerns due to polymeric material molding defects, and require additional metal reinforcements for structural support, leading to increased mass and complex assemblies.

Innovation Solution

A boot lid design featuring a structural reinforcement made from a single piece of polymeric material, covered on the outside by a rear window and trim panel, and on the inside by an interior lining, forming hollow frames that eliminate the need for metal reinforcements, enhancing rigidity and aesthetics while simplifying assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If additional metal reinforcements are added to the boot lid, then the rigidity and structural support are improved, but the overall mass and device complexity increase

Engineering Contradiction:
ImproverigidityVSAvoidoverall mass
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent employs composite material construction by integrating the structural reinforcement (made of polymeric material) with the interior lining to form a combined structure. This composite approach provides the necessary rigidity and structural support while avoiding the need for additional metal reinforcements, thereby reducing overall mass compared to traditional metal-based solutions

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The structural reinforcement and interior lining are merged into a single integrated assembly that works together to provide structural support. The interior lining is fixed to the structural reinforcement, and together they form hollow frames that enhance rigidity, eliminating the need for separate metal reinforcement components

Inventive Principle:
Principle #5Merging (Combining)

2Strength

If additional metal reinforcements are added to the boot lid, then the structural support is improved, but the assembly complexity and manufacturing cost increase

Engineering Contradiction:
Improvestructural supportVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The structural reinforcement and interior lining are combined into a single integrated assembly, reducing the number of separate components that need to be assembled. The interior lining is fixed to the structural reinforcement in one operation, simplifying the assembly process compared to separately installing metal reinforcements

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The structural reinforcement serves multiple functions: it provides structural support, forms the mounting surface for the interior lining, and creates the hollow frames that enhance rigidity. This multi-functionality reduces the need for additional specialized components

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If the structural reinforcement is made visible on the outside, then the manufacturing process is simplified, but the aesthetic appearance deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidaesthetic appearance
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The interior lining serves dual functions: it provides the finished aesthetic appearance visible from the vehicle interior, and simultaneously serves as a structural component that works with the reinforcement to form hollow frames for rigidity. This eliminates the need for separate cosmetic trim pieces

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Weight of moving object

If polymeric material is used for structural reinforcement, then the mass is reduced, but the rigidity may be insufficient without additional reinforcements

Engineering Contradiction:
ImprovemassVSAvoidrigidity
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent uses composite material construction by integrating the structural reinforcement (made of polymeric material) with the interior lining to form a combined structure. This composite approach provides the necessary rigidity and structural support while avoiding the need for additional metal reinforcements, thereby reducing overall mass compared to traditional metal-based solutions

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The structural reinforcement incorporates hollow frames that extend in multiple dimensions, creating a three-dimensional structural network. These hollow sections provide structural rigidity through their geometric configuration rather than relying solely on material thickness, enabling polymeric material to achieve adequate stiffness

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

Data Source

PatentEP2512850B1Motor vehicle trunk lid
Publication Date: 2013.12.18 RENAULT SA
  • EP2512850B1 patent drawingFigure 1~2
  • EP2512850B1 patent drawingFigure 3~4
  • EP2512850B1 patent drawingFigure 5~9

AI summary

The invention relates to a motor vehicle trunk lid (1) that includes: a structural reinforcement (18), an inner lining (42), and a rear window. The structural reinforcement (18) is made up of an upper portion, defining a rear window opening, and a lower portion that extends the upper portion toward the bottom of the trunk lid (1). According to the invention, the structural reinforcement (18) is produced from a single polymer material part. Said structural reinforcement is covered, on the outside thereof, by at least the rear window and by an outer decor panel placed under the rear window so as to completely cover the structural reinforcement (18), and said structural reinforcement is completely covered, on the inside thereof, by the inner lining (42). The structural reinforcement (18) and the inner lining (42) engage with each other so as to form, from a first closed section, a first hollow frame surrounding the rear window opening, and moreover form, from a second closed section, a peripheral second hollow frame located near the outer edges of the trunk lid (1).