Automotive Glass Run Plasticizer Layer
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Solution Overview
Problem
Conventional automotive glass runs made from thermoplastic elastomers experience permanent deformation over time, leading to a decrease in holding force and anti-shift force between the glass run and the door frame, resulting in position shifts.
Innovation Solution
Incorporating a plasticizer rich layer with a high concentration of plasticizer component on the holding lip and/or bottom wall of the glass run, which generates shrinkage and expansion forces as the plasticizer component migrates, maintaining the holding force and preventing position shifts despite compression set.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thermoplastic elastomer is used to manufacture the glass run, then ease of molding and recycling are improved, but permanent deformation occurs over time leading to decreased holding force
Solution Approach 1:
The patent applies local quality by creating a plasticizer-rich layer specifically in the holding lip region where holding force is critical. This localized concentration of plasticizer (5-20 times higher than the base material) provides enhanced flexibility and resistance to permanent deformation only where needed, while the rest of the glass run maintains its original material properties for ease of molding and recycling.
Solution Approach 2:
The patent creates a composite structure within the thermoplastic elastomer by incorporating a plasticizer-rich layer. This internal composite consists of the base thermoplastic elastomer matrix and the concentrated plasticizer layer, combining the advantages of both: the base material provides moldability and recyclability, while the plasticizer-rich layer provides long-term dimensional stability and sustained holding force.
2Ease of operation
If the glass run is deformed during assembly to fit the door frame, then assembly workability is improved, but compression set occurs reducing the restoring force over time
Solution Approach 1:
The patent applies preliminary action by pre-concentrating plasticizer in the holding lip region before assembly occurs. This pre-prepared plasticizer-rich layer is already in place to counteract the compression set that will occur during deformation and assembly, allowing the glass run to be deformed for easy assembly while maintaining the ability to recover and sustain holding force over time.
Solution Approach 2:
The plasticizer-rich layer acts as a beforehand cushioning mechanism against compression set. By having excess plasticizer预先 concentrated in the holding lip, the material is pre-prepared to resist permanent deformation when compressed during assembly, cushioning the negative effects of compression set before they can occur.
3Ease of operation
If a uniform plasticizer distribution is used throughout the glass run, then initial flexibility is improved, but permanent deformation increases over time
Solution Approach 1:
The patent rejects uniform plasticizer distribution in favor of local quality by concentrating plasticizer specifically in the holding lip region. This localized approach provides sufficient initial flexibility for assembly where needed, while preventing permanent deformation in the critical holding area by having excess plasticizer available to counteract compression set over time.
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 glass run maintains initial performance and durability by preventing position shifts and ensuring reliable attachment to the door frame, even after prolonged use, through the use of a plasticizer rich layer that adjusts its force distribution over time.
Implementation Method 1
a phenomenon occurs in which the plasticizer component moves from the plasticizer rich layer to the thermoplastic elastomer with the passage of time
Implementation Method 2
a restoring force acts on the holding lip to prevent a position shift of the vehicle-exterior side wall and the vehicle-interior side wall
Data Source
AI summary
An automotive glass run that is attached to an inner periphery of a door frame of an automotive door, guides ascending and descending of a door glass, and is formed of a thermoplastic elastomer, includes: a main body having a substantially U-shaped cross section, the main body including a vehicle-exterior side wall, a vehicle-interior side wall, and a bottom wall; a holding lip that extends from at least one of the vehicle-exterior side wall and the vehicle-interior side wall and abuts on the door frame; and a plasticizer rich layer formed on at least one side of the holding lip abutting on the door frame, the plasticizer rich layer including a large amount of plasticizer component compared to the thermoplastic elastomer forming the holding lip.