Thermoplastic Control Flap With Elastomer Seal And Pressure Plate
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Solution Overview
Problem
Control flaps used in turbochargers for exhaust gas recirculation face issues with mechanical property degradation and loss of sealing function due to high temperatures, and challenges in achieving a secure and cost-effective bond between thermoplastic flap bodies and elastomer seals, often requiring expensive processes and coupling agents.
Innovation Solution
A three-part control flap design featuring a thermoplastic flap body, an elastomer seal, and a thermoplastic pressure plate, where the seal has a convex sealing lip and undercut, and the pressure plate has fixing lugs and a central ventilation opening, allowing for secure bonding without coupling agents or surface treatments, using injection molding and welding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-component injection molding process is used to produce the control flap, then the bond between the flap body and seal is secure, but the production cost increases and the process becomes more complex
Solution Approach 1:
The control flap is divided into three separate components (flap body, seal, and pressure plate) that are produced independently and then assembled. This segmentation allows each component to be manufactured using simpler, more cost-effective processes while maintaining secure bonding through the pressure plate's fixing lugs that engage with the seal.
2Temperature
If high-temperature plastics like polyamide 4.6 are used for the flap body, then the component can withstand high temperatures, but the mechanical properties significantly decline and the surface can be damaged
Solution Approach 1:
The solution uses a composite structure where the flap body is made of thermoplastic (providing temperature resistance) and the seal is made of elastomer (providing mechanical flexibility and sealing capability). The pressure plate made of thermoplastic with glass fiber reinforcement provides both temperature resistance and enhanced mechanical strength, creating a composite system that balances both requirements.
3Reliability
If coupling agents and surface treatments are applied to achieve adhesion between thermoplastic and elastomer, then the bond strength improves, but the process costs increase and the time window for further processing decreases
Solution Approach 1:
The pressure plate design incorporates fixing lugs that mechanically engage with the seal's undercut, creating a self-locking mechanism that provides secure bonding without requiring additional coupling agents or surface treatments. The mechanical interlocking geometry itself provides the adhesion function, eliminating the need for chemical auxiliaries.
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 design provides a more secure, permanent, and cost-effective bond between the flap body and seal, enhancing temperature resistance and mechanical properties while eliminating the need for expensive two-component injection molding and surface treatments.
Implementation Method 1
The seal has an undercut for receiving a circumferential edge section of the pressure plate
Implementation Method 2
bonding the pressure plate and flap body
Data Source
AI summary
A control flap (1) has a flap body (2) and a circumferential seal (3) capable of sealing upon abutting to a sealing surface (7) of an opening (8). The flap body (2) and the seal (3) are made of elastomers. The seal (3) is joined to the flap body (2) by a pressure plate (4) made of a thermoplastic. The control flap may be made by a method that includes: producing the flap body (2) from a thermoplastic by injection molding; producing the pressure plate (4) from a thermoplastic by injection molding; producing the seal (3) from an elastomer by injection molding; introducing the pressure plate (4) into the undercut (10) of the seal (3); inserting the pressure plate (4) with the seal (3) into the recess (16) of the flap body (2) and bonding the pressure plate (4) and flap body (2).