Dual-Hardness Piston Ring Structure for High-Pressure Sealing
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Solution Overview
Problem
Conventional piston rings deform under pressure, compromising their sealing effectiveness in compressors, particularly when handling high-pressure gases like hydrogen.
Innovation Solution
A piston ring design featuring a first ring portion and a second ring portion with varying hardness levels, where the second ring portion, positioned opposite to the compression chamber, provides additional support to prevent deformation of the first ring portion, ensuring reliable sealing by maintaining close contact with the cylinder's inner wall surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-ring piston ring is used, then the structure is simple, but the sealing reliability deteriorates under high gas pressure due to deformation
Solution Approach 1:
The piston ring is divided into two separate ring members: a first ring member that contacts the cylinder inner wall surface, and a second ring member with higher hardness positioned on the opposite side. This segmentation allows each ring member to perform its specific function - the first provides sealing contact while the second provides structural support against gas pressure, resolving the contradiction between sealing reliability and structural simplicity.
Solution Approach 2:
Different regions of the piston ring assembly are given different properties: the first ring member has properties optimized for sealing (softer material for conformability), while the second ring member has higher hardness for withstanding gas pressure. This local differentiation of properties allows the system to simultaneously achieve reliable sealing and resistance to deformation under pressure.
2Reliability
If the piston ring is made softer for better sealing contact, then sealing property improves, but resistance to gas pressure deformation worsens
Solution Approach 1:
The piston ring function is segmented into two separate members with different material properties. The first ring member uses softer material for optimal sealing contact, while the second ring member uses harder material for structural support. This eliminates the need to compromise between sealing and strength in a single homogeneous ring.
Solution Approach 2:
Different material properties are assigned to different parts of the piston ring assembly. The first ring member has lower hardness for better conformability and sealing, while the second ring member has higher hardness for strength. This local quality differentiation resolves the contradiction between softness for sealing and hardness for pressure resistance.
Data Source
AI summary
A piston ring includes a first ring portion which is fitted onto an outer circumferential portion of a piston and which is capable of sliding relative to an inner wall surface of a cylinder, and a second ring portion which is fitted onto the outer circumferential portion of the piston, arranged side-by-side with the first ring portion in the axial direction, and which is capable of sliding relative to the inner wall surface of the cylinder. The second ring portion is fitted onto the outer circumferential portion of the piston in such a way as to be positioned on a side opposite to a compression chamber inside the cylinder, relative to the first ring portion, and has a greater hardness than the first ring portion has.