TPV Co-extruded Header Trim for Curved Window Conformance

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Solution Overview

Problem

Existing upper reveals for motor vehicle door frames with curved window openings often suffer from appearance flaws like crimping, creasing, and visible joints when bent to conform to curved portions, and require costly tooling for manufacturing.

Innovation Solution

A method using thermoplastic vulcanizate (TPV) co-extruded with a carrier, cured, and heated to deform, allowing for bending to conform to curved window openings while applying decorative trim and end caps for aesthetic and structural enhancement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the upper reveal is bent to conform to curved portions of the window opening, then it can accommodate the curved styling of the motor vehicle, but appearance flaws such as crimping, creasing, bulging, and buckling occur

Engineering Contradiction:

Improveability to conform to curved window openingVSAvoidappearance quality of upper reveal

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The upper reveal is divided into two segments: a thermoset portion (PVC or EPDM rubber) and a thermoplastic portion (TPV). The thermoplastic portion is specifically designed to be heat-formed and bent to conform to curved portions, while the thermoset portion maintains structural integrity and provides sealing engagement. This segmentation allows each material to perform its specialized function without compromising overall appearance or adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes heat formation by heating the thermoplastic portion to a temperature above its glass transition temperature, making it pliable and formable. This temporary parameter change allows the material to be bent to desired curvatures and then cooled to lock in the new shape, achieving complex geometries without appearance flaws that would result from cold-forming.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If discrete extruded and stamped portions are used to conform to curvature, then appearance flaws are avoided, but a visible joint is created at the interface

Engineering Contradiction:

Improveappearance quality of upper revealVSAvoidnumber of separate components

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the thermoset material and thermoplastic material into a single co-extruded upper reveal component. The thermoplastic portion is co-extruded with the thermoset material, creating a seamless integrated structure. This merging eliminates visible joints and interfaces while maintaining the ability to conform to curved portions through heat formation of the thermoplastic segment.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If stamped metal portions are used to create curved sections, then conformance to curvature is achieved, but expensive tooling is required for manufacturing

Engineering Contradiction:

Improveability to conform to curved window openingVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive stamped metal portions with a thermoplastic portion that achieves curvature through heat formation. By heating the thermoplastic material above its glass transition temperature and forming it to the desired shape, complex curved geometries can be achieved using relatively simple forming tools rather than expensive stamped metal tooling, significantly reducing manufacturing costs while maintaining adaptability to curved window openings.

Inventive Principle:

Principle #35Parameter changes

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 method provides a cost-effective, aesthetically pleasing upper reveal that conforms to curved window openings without appearance flaws and eliminates the need for expensive tooling, ensuring a seamless integration with the vehicle's design.

Implementation Method 1

heating the upper reveal to a temperature greater than a heat deformation temperature of the TPV

Methodology Applied

Scientific EffectHeat deformation: Thermal Expansion

Implementation Method 2

curing the TPV to form the upper reveal

Methodology Applied

Scientific EffectCuring: Photopolymerisation

Data Source

PatentUS7531118B2Heat formed TPV co-extruded header trim

Publication Date: 2009.05.12 DECOMA INT

AI summary

A method is provided for manufacturing an upper reveal that conforms to a curved portion of a window opening of a motor vehicle door frame. The upper reveal is formed from TPV and a carrier. The method includes the steps of: co-extruding the TPV with the carrier; curing the TPV to form the upper reveal; heating the upper reveal to a temperature greater than a heat deformation temperature of the TPV; and bending the upper reveal to conform to the curved portion of the window opening of the motor vehicle door frame.