Piston Sealing Ring Assembly With Gap Covers for Wear Leakage
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Solution Overview
Problem
Seals in piston and cylinder devices, particularly those using self-lubricating materials, experience unacceptable leakage and increased stress due to radial wear, leading to reduced operational life and potential breakage.
Innovation Solution
A sealing ring assembly with gap cover elements that maintain contact with the cylinder bore by expanding radially outward as the ring wears, using wedge-shaped recesses and gap cover elements to form a seal, reducing leakage and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the seal is made from self-lubricating material to reduce friction and wear, then ease of operation is improved, but leakage increases due to higher wear rates
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. The gap cover elements bridge these gaps to prevent leakage while allowing radial movement.
Solution Approach 2:
The ring segments are designed to move radially outward as wear occurs, maintaining sealing pressure against the cylinder wall. The gap cover elements dynamically adjust to the changing gap dimensions while maintaining the seal.
2Duration of action of stationary object
If the seal is split into ring segments to compensate for radial wear, then duration of action is improved, but leakage increases due to opened gaps
Solution Approach 1:
Gap cover elements are introduced as intermediary components that bridge the gaps between ring segments. These gap covers prevent direct leakage paths while allowing the ring segments to move radially and maintain sealing contact.
Solution Approach 2:
The seal is divided into multiple ring segments with gaps between them, allowing each segment to move independently and maintain sealing contact despite wear. The gap cover elements bridge these gaps to prevent leakage while allowing radial movement.
3Reliability
If the ring gaps are covered from the front to prevent leakage, then reliability is improved, but bending stress increases dramatically in the front cover ring
Solution Approach 1:
The gap cover function is extracted from the main ring structure and implemented as separate, lightweight gap cover elements. This removes the bending stress problem from the front cover ring while maintaining leakage prevention through the gap cover elements positioned at the low-pressure rear.
4Duration of action of stationary object
If the gap width increases due to wear to maintain sealing contact, then duration of action is improved, but leakage increases through the larger gap
Solution Approach 1:
Gap cover elements are introduced as intermediary components that bridge the gaps between ring segments. These gap covers prevent direct leakage paths while allowing the ring segments to move radially and maintain sealing contact.
Solution Approach 2:
The ring segments are designed to move radially outward as wear occurs, maintaining sealing pressure against the cylinder wall. The gap cover elements dynamically adjust to the changing gap dimensions while maintaining the seal.
Data Source
AI summary
The present disclosure provides a sealing ring assembly having ring segments configured to seal a high-pressure region from a lower pressure region of a piston and cylinder device. The sing segments are configured to move radially outward and wear during operation of the piston via the cylinder device. The ring segments include, for example, wedge-shaped features that engage with corresponding wedge recesses in the interfaces between ring segments. The sealing ring assembly may include a high-pressure boundary and a low-pressure boundary. As the sealing ring wears, the ring segments stay engaged with the interfaces, so that ring gaps do not form on the low pressure boundary.