Overmolded Motorized Valve Sealing With a Single Dynamic Seal
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Solution Overview
Problem
Current motorized EGR valves face challenges with sealing, assembly complexity, and thermal dissipation, particularly requiring multiple seals and cumbersome elastic return mechanisms, which can lead to friction and assembly difficulties.
Innovation Solution
The use of plastic overmolding with liquid crystallized polymer material for both the actuator and tubing, combined with a magnetic return mechanism and a single dynamic seal, creates a compact, lightweight assembly with enhanced sealing and reduced friction, eliminating the need for multiple seals and improving thermal dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single lip dynamic seal is used between the valve body and insert guide bearing, then the sealing function is simplified, but exhaust gas can rise along the actuator axis and damage the actuator
Solution Approach 1:
A plastic overmolding is introduced as an intermediary component between the actuator and valve body. This overmolding extends along the actuator axis and is secured to both components, creating a protective barrier that prevents exhaust gas from reaching the actuator while maintaining the simplicity of the single seal configuration.
2Reliability
If an O-ring gasket is used between the actuator stator and valve, then external agents are prevented from penetrating, but the assembly complexity increases
Solution Approach 1:
The protective function previously requiring a separate O-ring gasket is merged into the plastic overmolding structure. The overmolding itself provides the sealing barrier against external agents, eliminating the need for additional sealing components and simplifying the overall assembly.
3Weight of moving object
If aluminum is used for the entire valve body, then the valve is lighter, but thermal dissipation capability is reduced at high operating temperatures
Solution Approach 1:
The valve employs a composite construction combining aluminum (for lightness) with plastic overmolding material (for thermal management). The plastic overmolding can be formulated with thermal management properties to compensate for the lower thermal conductivity of aluminum, achieving both weight reduction and adequate thermal dissipation.
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
This solution achieves total tightness with a single seal, reduces assembly complexity, and enhances the lifespan of the valve by minimizing friction and wear, while maintaining compactness and robustness.
Implementation Method 1
a plastic overmolding material surrounding and being secured at least in part to the actuator and forming at least part of the tubing, the static seal being achieved by the plastic overmolding material common between the actuator and the tubing
Implementation Method 2
The actuator is provided with a means for restoring the position of the rotor (5) in the event of a failure ('failsafe'), of a magnetic nature
Implementation Method 3
The use of plastic overmolding with liquid crystallized polymer material for both the actuator and tubing
Data Source
Figure 1~2
Figure 3~4
Figure 5a~6b
AI summary
The invention proposes a motorized valve made up of a closable pipe, of a valve shutter, of a rotary electromagnetic actuator and of an overmoulding plastic material, said actuator being formed of a stator assembly, of a rotor secured to a spindle, the shutter being positioned progressively by said actuator using the spindle and able to shut off the pipe, the overmoulding plastic material surrounding and being secured at least in part to the actuator and forming the pipe at least in part, characterized in that static sealing is afforded by the overmoulding plastic material common to the actuator and the pipe, said overmoulding material having passing through it a passage that is rendered fluidtight for guiding the spindle that connects the shutter and the rotor.