Outer Weatherstrip Plasticizer Layer Deformation
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Solution Overview
Problem
Automotive outer weatherstrips using thermoplastic elastomers suffer from permanent deformation, leading to reduced sealing effectiveness and impaired visibility due to decreased restoring force between the seal lips and door glass, allowing foreign matter to enter the vehicle.
Innovation Solution
A thermoplastic elastomer outer weatherstrip with a plasticizer-rich layer having a higher proportion of plasticizer component than the seal lip, formed on the side abutting the door glass, generates contraction and expansion forces to maintain initial holding force and prevent foreign matter entry, while maintaining durability and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermoplastic elastomer is used for the outer weatherstrip, then ease of molding and recycling are improved, but permanent deformation occurs in the seal lips leading to reduced sealing effectiveness
Solution Approach 1:
The patent changes the chemical composition parameters of the thermoplastic elastomer by adding specific antioxidants (such as hindered phenol antioxidants and phosphite antioxidants) and process oils in controlled amounts. This parameter change prevents permanent deformation while maintaining the ease of molding characteristic of thermoplastic elastomers, thus resolving the contradiction between manufacturability and sealing reliability.
Solution Approach 2:
The patent creates a composite material system by combining thermoplastic elastomer with specific additives including antioxidants and process oils. This composite formulation enhances the durability and resistance to permanent deformation of the seal lips while retaining the processing advantages of thermoplastic elastomers, thereby maintaining both ease of manufacture and sealing effectiveness.
2Reliability
If the door glass is kept in a closed state to improve sound insulation and air conditioning performance, then in-vehicle comfort is improved, but the seal lips are held in a most bending state for long periods causing permanent deformation
Solution Approach 1:
The patent applies beforehand cushioning by incorporating antioxidants and process oils into the thermoplastic elastomer formulation before manufacturing. These additives preemptively protect the seal lips from permanent deformation during prolonged bending states, allowing the door glass to remain closed for improved comfort without compromising seal lip durability.
Solution Approach 2:
The patent modifies the material parameters of the thermoplastic elastomer by controlling the types and amounts of antioxidants and process oils. This parameter optimization enables the seal lips to withstand prolonged bending states caused by closed door glass, thereby maintaining both in-vehicle comfort and seal lip durability.
3Reliability
If the distal end portion of the seal lip is increased in thickness to improve restoring force, then sealing performance is improved, but material usage and weight increase
Solution Approach 1:
The patent changes the material composition parameters rather than relying solely on geometric thickening. By optimizing the thermoplastic elastomer formulation with specific antioxidants and process oils, the patent achieves improved restoring force and sealing performance without necessarily increasing the thickness of the distal end portion, thus avoiding excessive weight gain.
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 outer weatherstrip maintains sealing effectiveness and visibility by compensating for permanent deformation, ensuring secure sealing and effective removal of debris from the door glass, without increasing material usage or weight.
Implementation Method 1
a plasticizer-rich layer containing a higher proportion of a plasticizer component compared to the plasticizer component contained in the thermoplastic elastomer forming the seal lip is formed on a side of the seal lip abutting on the door glass
Data Source
AI summary
An outer weatherstrip formed of a thermoplastic elastomer fitted to an upper edge portion of a door panel of an automobile door, for sealing a space between the door panel and a door glass includes a main body consisting of a vehicle interior-side side wall, a top wall, and a vehicle exterior-side side wall, and an upper seal lip and a lower seal lip protruding from the vehicle interior-side side wall to the door glass side. A plasticizer-rich layer and a plasticizer-rich layer containing a higher proportion of a plasticizer component compared to the thermoplastic elastomer forming the upper seal lip and the lower seal lip are formed on the sides of the upper seal lip and the lower seal lip abutting on the door glass.