Folding Top Compartment Lid Composite Assembly

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Solution Overview

Problem

Existing convertible top compartment flaps face challenges in achieving sufficient stiffness and lightness while simplifying the hinge connection, as well as reducing the size of the body shell without compromising overall stiffness.

Innovation Solution

A top compartment flap comprising a shell component and a self-supporting assembly part, where the assembly part is made of composite material with a sandwich design, providing additional rigidity and weight reduction, and is mounted after the painting process, allowing the shell component to be smaller and lighter, with a U-shaped design and a decorative layer forming a parcel shelf.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a double-shell metallic construction is used for the convertible top compartment flap, then sufficient stiffness is achieved, but the weight increases

Engineering Contradiction:
ImprovestiffnessVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining a metallic double-shell structure with a plastic trim piece that has load-bearing functionality. The plastic component is integrated into the assembly to provide structural support, allowing the metallic shells to be thinner and lighter while maintaining overall stiffness. This composite approach resolves the contradiction by using materials with complementary properties - the metal provides rigidity and the plastic provides lightweight structural support.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent merges the decorative trim piece with the load-bearing structure by designing the plastic component to serve dual functions: aesthetic coverage and structural support. The trim piece is integrated with the hinge connection and mounting structures, combining what were previously separate functional elements into a unified assembly that reduces overall weight while maintaining stiffness.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If a plastic trim piece is added to the outer shell for interior functionality, then aesthetic and functional requirements are met, but the complexity of assembly increases

Engineering Contradiction:
Improveinterior functionalityVSAvoidassembly complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the decorative trim piece with load-bearing structural elements, including the hinge connection and mounting structures, into a single integrated plastic component. This merging eliminates the need for separate assembly steps for attaching trim and structural elements, reducing overall assembly complexity while providing both aesthetic and functional benefits.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The plastic trim piece is designed to serve multiple functions simultaneously: it provides aesthetic coverage for the interior, structural load-bearing capacity to support the flap, and integration points for hinge connections. This multi-functionality reduces the number of separate components needed, thereby simplifying the overall assembly process.

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

3Weight of moving object

If the body-in-white portion is reduced in size, then weight is reduced, but the stiffness may be compromised

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

Solution Approach 1:

The patent compensates for the reduced size and potential stiffness loss of the metallic body-in-white by introducing a plastic component with integrated load-bearing structures. The plastic material, while lighter, is designed with reinforcement elements and structural geometries that provide sufficient stiffness to maintain overall flap rigidity despite the smaller metallic portion.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent merges the metallic double-shell structure with the plastic trim piece to create a hybrid assembly where each material contributes its strengths. The reduced metallic body-in-white is compensated by the plastic component's structural design, which includes reinforced areas and integrated mounting structures that collectively maintain the required stiffness while reducing overall weight.

Inventive Principle:
Principle #5Merging (Combining)

4Weight of moving object

If a multi-layered composite component is used, then weight is reduced, but the hinge connection becomes difficult to implement

Engineering Contradiction:
ImproveweightVSAvoidhinge connection
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent integrates the hinge connection structures directly into the plastic trim piece during its molding process. The hinge mounting elements, reinforcement structures, and attachment points are built into the plastic component as a single integrated piece, eliminating the need for complex post-assembly operations to attach hinges to a multi-layered composite structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hinge connection structures are pre-formed as integral parts of the plastic trim piece during the molding process. This preliminary action of incorporating hinge mounting features into the base plastic component simplifies subsequent assembly steps, as the hinge can be directly attached to the pre-prepared integration points without requiring complex modification or additional fastening operations.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3429877B1Folding top compartment lid
Publication Date: 2021.05.05 BAYERISCHE MOTOREN WERKE AG
  • EP3429877B1 patent drawingFigure 1~2
  • EP3429877B1 patent drawingFigure 3~4

AI summary

A folding top compartment lid (1) according to the invention for closing an opening in a folding top compartment of a cabriolet consists at least of a bodyshell component (3) and a self-supporting mounted part (5). The self-supporting mounted part (3) adjoins the bodyshell component (4) in such a way that the bodyshell component (3) on its own closes a section of the opening in the folding top compartment and the mounted part (5) on its own closes a section of the opening in the folding top compartment.