Piston Sealing Ring Assembly With Gap Cover for Wear-Induced Leakage
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Solution Overview
Problem
Sealing ring assemblies in piston and cylinder devices face challenges with radial wear, leading to increased leakage and stress due to gap formation between ring segments, especially when using self-lubricating materials that exhibit higher wear rates, resulting in reduced operational life and potential breakage.
Innovation Solution
The sealing ring assembly incorporates a gap cover element that widens as the ring wears, maintaining contact with the cylinder bore and preventing significant gaps from forming, utilizing wedge-shaped recesses and gap cover elements to restrict gas leakage and mitigate stress by self-adjusting wear rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a self-lubricating material is used for the seal, then lubrication is improved, but wear rate increases leading to higher leakage
Solution Approach 1:
The seal is divided into multiple ring segments with gaps between them, allowing each segment to move independently and maintain sealing contact despite wear, while the segmented structure accommodates the higher wear rate of self-lubricating materials
Solution Approach 2:
The ring segments are designed to be dynamic rather than fixed, allowing them to move radially outward as wear occurs, maintaining sealing effectiveness throughout the seal's operational life despite the higher wear rate inherent to self-lubricating materials
2Reliability
If the seal is split into ring segments to compensate for radial wear, then sealing contact is maintained, but gap width increases leading to unacceptable leakage
Solution Approach 1:
A gap cover element is introduced as an intermediary component that spans the gaps between ring segments, preventing direct leakage paths while allowing the segments to maintain sealing contact with the cylinder wall
Solution Approach 2:
The sealing approach transitions from relying solely on radial sealing contact to also utilizing axial sealing with the gap cover element, adding a dimensional aspect that blocks leakage paths without compromising the radial sealing function
3Reliability
If the ring gaps are covered from the front, then sealing is improved, but bending stress increases dramatically as gap width increases
Solution Approach 1:
Instead of having the front ring cover the gap (which creates bending stress), the gap cover element is positioned on the rear side of the seal, inverting the conventional approach and eliminating the bending stress problem while maintaining sealing effectiveness
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 maintains low leakage and reduces stress at ring gaps throughout the operational life of the seal, ensuring effective sealing performance even with high wear rates, thereby extending the seal's operational life and preventing breakage.
Implementation Method 1
the gap cover element is configured to move radially outward to maintain the seal as the interface widens
Implementation Method 2
the first and second end faces form a wedge-shaped recess and the gap cover element includes a wedge configured to engage with the wedge-shaped recess
Data Source
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AI summary
The present disclosure provides a sealing ring assembly having a ring and one or more gap cover elements, configured to seal a high-pressure region from a lower pressure region of a piston and cylinder device. The ring may be segmented, and the gap cover elements may engage with interfaces between the ring segments. The gap cover elements are configured to move radially outward and wear as the ring wears. The gap cover elements may include, for example, wedge- shaped features that engage with corresponding wedge recesses in the interfaces. The sealing ring assembly may include a high-pressure boundary and a low-pressure boundary. As the sealing ring wears, the gap cover elements stay engaged with the interfaces, so that ring gaps do not form on the low pressure boundary.