Valve Stem Seal Geometry for High-Pressure Gas Leakage Control
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Solution Overview
Problem
Conventional valve stem seals fail to adequately prevent gas leakage from intake or exhaust ports towards the lubricating oil chamber in high-pressure turbo engines and EGR systems, despite their design to seal and lubricate the annular gap between the valve stem and guide.
Innovation Solution
The valve stem seal features a reinforcement ring with a rubber-like elastic body, including a seal section and a fitting section with annular seal protrusions, where the first seal protrusion is closer to the seal section and the second seal protrusion is farther away, with specific inclinations of their surfaces to optimize surface pressure and prevent gas leakage and oil penetration respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional seal protrusions with equal inclinations are used, then workability during fitting is improved, but sealing performance against high gas pressure is insufficient
Solution Approach 1:
The patent applies asymmetry by configuring seal protrusions with different inclination angles on opposite sides. The first seal protrusion has a first inclination angle on its first inclined surface and a second inclination angle on its second inclined surface, where the first inclination angle is different from the second inclination angle. This asymmetric design allows optimization of both fitting workability and sealing performance against high gas pressure, resolving the technical contradiction between ease of manufacture and reliability.
2Ease of operation
If seal protrusions are designed for easy fitting, then manufacturing workability improves, but gas leakage prevention capability deteriorates under high pressure
Solution Approach 1:
The patent applies local quality by giving different inclination angles to different surfaces of the seal protrusion. The first inclined surface has a first inclination angle optimized for fitting workability, while the second inclined surface has a second inclination angle optimized for preventing gas leakage. This localized differentiation of geometric properties allows each surface to perform its specific function optimally, resolving the contradiction between ease of operation and harmful factors.
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 configuration significantly enhances sealing performance while improving workability during fitting, effectively suppressing gas leakage and oil penetration, even in high-pressure engines.
Implementation Method 1
a rubber-like elastic body which is integrally provided with the reinforcement ring, the valve stem seal being configured to be fixed to a valve stem guide that guides a valve stem
Implementation Method 2
a plurality of annular seal protrusions, each including a first inclined surface having a diameter that increases from a radially inward tip toward the seal section and a second inclined surface having a diameter that increases from a radially inward tip toward a side opposite to the seal section
Data Source
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AI summary
A valve stem seal with significantly improved sealing performance while improving workability when fitting the valve stem seal to a valve stem guide. An inner peripheral surface of a fitting section (20B) is provided with a plurality of annular seal protrusions which respectively include first (25a, 26a) and second inclined surfaces (25b) and (26b), a first seal protrusion (25) which is closest to the seal section (20A) is configured so that an inclination of the second inclined surface (25b) is smaller than that of the first inclined surface (25a), and a second seal protrusion (26) which is farthest from the seal section (20A) is configured so that an inclination of the first inclined surface (26a) is smaller than that of the second inclined surface (26b). The valve stem seal can comprise a plurality of said first seal protrusions (25) and a plurality of said second seal protrusions (26).