Vehicle Window Assembly Integrated Elastomeric Seal Overmolding
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Solution Overview
Problem
Existing vehicle window assemblies for transit vehicles, such as school buses, face challenges in providing a reliable and watertight seal between the window panels and frames, especially when the movable window is in operation, often requiring separate seals that can be cumbersome and less effective.
Innovation Solution
A window assembly featuring a polymeric or plastic frame with an elastomeric seal overmolded onto the frame members, creating a two-shot molding process that integrates the seal directly into the frame, ensuring a secure and watertight connection between the fixed and movable window panels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate seals are used in traditional aluminum frame window assemblies, then the sealing function can be provided, but the assembly complexity increases and the seal effectiveness decreases
Solution Approach 1:
The elastomeric seal is integrated directly into the polymeric frame structure through overmolding, combining the sealing function with the frame itself. This eliminates separate seal components and their associated assembly steps, thereby reducing assembly complexity while maintaining or improving seal effectiveness through direct integration.
Solution Approach 2:
The frame is constructed as a composite structure combining a rigid polymeric material for structural support with an elastomeric material for sealing. This composite approach allows the frame to provide both structural integrity and sealing functionality, resolving the contradiction between seal effectiveness and assembly complexity.
2Reliability
If traditional aluminum frames with separate seals are used, then manufacturing is straightforward, but the watertight seal reliability is insufficient
Solution Approach 1:
The frame combines rigid polymeric material for structural support with elastomeric material for sealing through overmolding. This composite structure achieves superior watertight seal reliability while the overmolding process integrates sealing into the manufacturing workflow, maintaining ease of manufacture.
Solution Approach 2:
The elastomeric seal is self-integrated into the frame structure through the overmolding process, where the seal material is molded directly onto the frame during manufacturing. This self-service approach eliminates the need for separate seal installation steps, ensuring watertight reliability without compromising manufacturing simplicity.
3Device complexity
If the seal is integrated into the frame via overmolding, then assembly is simplified and seal reliability is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The overmolding process merges the frame and seal manufacturing into a single integrated operation, where the elastomeric seal is molded directly onto the rigid frame structure. This consolidation simplifies assembly by eliminating separate seal components while the integrated molding process manages manufacturing complexity through process integration rather than additional steps.
Solution Approach 2:
The frame structure serves its own sealing function through the overmolded elastomeric material, which is applied and cured as part of the frame manufacturing process itself. This self-service approach to sealing reduces assembly complexity without requiring separate manufacturing processes, as the seal is created during frame production.
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 integrated elastomeric seal enhances the assembly process by eliminating the need for separate seals and provides a robust, watertight seal across varying frame dimensions, ensuring improved weatherproofing and durability of the window assembly.
Implementation Method 1
The frame (such as a polycarbonate or acrylonitrile styrene acrylate (ASA) material or the like) and seal (such as a thermoplastic elastomer (TPE) or the like) may be formed via a two shot molding process, with the first shot molding the frame or at least the side frame members or portions and the second shot molding the elastomeric seal at the selected portions of the frame or frame members.
Data Source
AI summary
A window assembly for a vehicle includes a fixed frame having a pair of opposite side frame members, an upper frame member and a lower frame member. A fixed window panel is disposed at a lower portion of the side frame members and at the lower frame member. A movable window panel is movable relative to the fixed window panel and the frame between an opened position and a closed position. Each of the side frame members includes a lower channel for receiving a side perimeter edge region of the fixed window panel and an end region of the lower frame member. An elastomeric seal is overmolded along the lower channel of the side frame member and is configured to receive and seal against (i) the side perimeter edge region of the fixed window panel and (ii) the end region of the lower frame member.