Piston-Integrated Gap Cover for Wear-Resistant Ring Sealing
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Solution Overview
Problem
Seal rings with self-lubricating materials face significant leakage issues due to radial wear, which limits their operational life and performance, especially when split into segments, as the gaps between segments open, allowing pressure to escape.
Innovation Solution
A piston assembly design that incorporates a gap-cover feature extending axially from the rear land of the piston groove, engaging the axially rearward surface of the first ring and radially outside surfaces of the second ring, forming a gas seal and maintaining contact even as the second ring wears, thereby preventing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a seal ring is split into segments to compensate for radial wear, then the seal can maintain contact with the cylinder wall, but the gaps between segments open and cause unacceptable leakage flow
Solution Approach 1:
A gap cover element is introduced as an intermediary component between the piston and the segmented seal ring. This gap cover has a radially inward surface that contacts the radially outside surfaces of the seal ring segments, preventing gas from escaping through the gaps while allowing the segments to maintain radial contact with the cylinder wall despite wear
Solution Approach 2:
The solution addresses the two-dimensional gap problem (radial and azimuthal directions) by introducing a third dimensional element - the axially extending gap cover that protrudes from the piston face into the ring groove, creating a three-dimensional sealing structure that blocks leakage paths without preventing radial seal contact
2Ease of operation
If self-lubricating material is used for the seal, then lubrication is provided, but wear rates are relatively high causing gap opening
Solution Approach 1:
The harmful effect of high wear is extracted and isolated from the sealing function. The gap cover element is positioned to prevent leakage through wear gaps, effectively separating the wear management function from the sealing function, allowing the self-lubricating seal to wear without compromising seal integrity
Data Source
AI summary
The present disclosure provides a sealing ring assembly with one or more piston-integrated gap cover features, configured to seal a high-pressure region from a relatively lower pressure region of a piston and cylinder device. The sealing ring assembly may include two rings which each may include one or more ring segments. The one or more gap-cover features, which may be in the form of protrusions in the piston ring groove, may engage with corresponding flat sections of the ring segments. As the sealing ring wears, the gap-cover features may stay engaged with the ring segments, thereby maintaining a seal.