Stacked Piston Ring Structure to Prevent Protrusion Shift
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Solution Overview
Problem
In piston rings with low-pressure and high-pressure side rings, the high-pressure side ring's protrusion can shift circumferentially, leading to increased clearance and stress concentration, potentially causing fatigue failure.
Innovation Solution
A piston ring design where the low-pressure side ring and high-pressure side ring are stacked with rotation restriction parts to maintain their positions, ensuring the low-pressure side protrusion of the high-pressure side ring is evenly spaced, preventing shifting and stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the high-pressure side ring and low-pressure side ring are arranged stacked and movable in the circumferential direction, then the fluid-tightness is improved by protrusions entering abutments, but the protrusion may shift circumferentially causing increased clearance and stress concentration
Solution Approach 1:
The invention introduces asymmetric features: a rotation restriction groove on one side of the low-pressure side ring and a corresponding rotation restriction protrusion on the high-pressure side ring. This asymmetric design prevents circumferential shifting while maintaining the symmetric stacked arrangement for fluid-tightness, thereby resolving the contradiction between fluid-tightness and stress concentration resistance.
Solution Approach 2:
The rotation restriction groove and protrusion are pre-configured in specific positions before operation. This preliminary positioning ensures that the high-pressure side ring cannot shift circumferentially during operation, preventing the clearance increase and stress concentration that would otherwise occur during pump operation.
2Reliability
If the protrusion is inserted in the abutment to prevent leakage, then fluid-tightness is improved, but the protrusion may become arranged shifted to one side leading to fatigue failure
Solution Approach 1:
The asymmetric rotation restriction groove and protrusion configuration prevents circumferential shifting of the stacked rings during operation. This ensures that the protrusion remains properly positioned in the abutment throughout the service life, preventing both leakage and fatigue failure, thereby extending the durable operation period.
Solution Approach 2:
The rotation restriction features are pre-positioned to maintain proper alignment before operation begins. This preliminary positioning prevents the protrusion from shifting during operation, ensuring both leakage prevention and fatigue resistance over the extended service life.
3Ease of operation
If clearances are provided in both sides to allow movement, then the rings can adjust position, but the protrusion may shift to one side causing stress concentration
Solution Approach 1:
The invention uses asymmetric rotation restriction features (groove and protrusion) that allow controlled position adjustment while preventing uncontrolled circumferential shifting. The clearances are maintained for necessary adjustment, but the asymmetric restriction prevents the protrusion from shifting to one side, thereby maintaining stress distribution and preventing fatigue failure.
Data Source
AI summary
Provided is a piston ring including: a low-pressure side ring; and a high-pressure side ring, the low-pressure side ring and the high-pressure side ring are arranged stacked in a direction along the axis so that the high-pressure side ring is closer to a fluid to be compressed, a low-pressure side rotation restriction part configured to restrict rotation in the circumferential direction relative to the piston is formed to the low-pressure side ring, a high-pressure side rotation restriction part configured to restrict rotation in the circumferential direction relative to the piston and a low-pressure side protrusion protruding toward the low-pressure side ring and inserted in the low-pressure side abutment are formed to the high-pressure side ring, and the low-pressure side protrusion is inserted in a low-pressure side abutment with clearances being provided in both sides in the circumferential direction between the low-pressure side ring and the low-pressure side protrusion.