Barrel-Shaped Piston Ring Sealing Non-Overlapping Regions
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Solution Overview
Problem
Piston rings experience thermal deformation due to temperature differences, leading to uneven wear and potential gaps between the inner peripheral surface of the cylinder and the piston ring, which can result in combustion gas leakage and reduced durability.
Innovation Solution
The piston ring features a barrel-shaped outer peripheral surface with continuous barrel centers on the first and second tongue sections, ensuring sealing performance even in non-overlapping regions and reducing slide friction, thus preventing uneven wear and gas leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the piston ring has a uniform barrel shape over the entire circumference, then the manufacturing is simple, but the sealing performance deteriorates in non-overlapping regions due to thermal deformation
Solution Approach 1:
The piston ring applies local quality by providing barrel shapes at specific locations (first and second tongue sections) rather than uniformly across the entire ring. This localized barrel shaping addresses thermal deformation issues in critical non-overlapping regions while maintaining manufacturing feasibility, resolving the contradiction between manufacturing simplicity and sealing performance.
Solution Approach 2:
The piston ring segments the barrel shape application into distinct regions - the first tongue section, second tongue section, and body section - with barrel shapes provided only at the tongue sections. This segmentation allows targeted sealing enhancement where thermal deformation occurs most severely without requiring complex barrel shaping across the entire ring, balancing manufacturing ease with reliability.
2Reliability
If the outer peripheral surface is formed into a barrel shape, then sealing performance improves, but thermal deformation causes uneven wear on the cylinder inner peripheral surface
Solution Approach 1:
The invention applies local quality by restricting barrel shapes to specific tongue sections rather than the entire circumference. This localized approach provides sealing enhancement where end gaps create vulnerability to thermal deformation, while avoiding excessive barrel shape-induced contact pressure that would cause uneven wear on the cylinder surface.
Solution Approach 2:
The invention converts the harmful effect of thermal deformation into a beneficial design feature by positioning barrel shapes at tongue sections - the exact regions most susceptible to thermal deformation. The barrel shapes compensate for the bulging caused by thermal expansion, transforming the deformation problem into a controlled sealing solution that prevents both leakage and uneven wear.
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
The solution enhances the durability of the piston ring and engine by maintaining effective sealing and reducing combustion gas flow-through in non-overlapping regions, while minimizing uneven wear and contact pressure.
Implementation Method 1
A piston ring has elasticity, and is in slide contact with an inner peripheral surface of a cylinder with a suitable surface pressure, thereby functioning to maintain a pressure in a combustion chamber
Implementation Method 2
the temperature on the inner peripheral side of the piston ring is higher than that on the outer peripheral side. Accordingly, a thermal expansion amount of the piston ring is greater at the inner peripheral side than at the outer peripheral side
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
The purpose of the present invention is to provide a gas-tight piston ring which suppresses combustion gas blow-by in non-overlapping regions of a first tongue section and a second tongue section and has improved durability. The present invention comprises: a body section (10a) which extends in the circumferential direction around an axis (CL); a first tongue section (12) which extends from one end (10b) of the body section (10a) to the other end (10c) and in which a fitting groove (12c) is formed that extends in the circumferential direction at one side in the direction along the axis (CL) and is at the radially outer side of the body section (10a); and a second tongue section (13) which extends from the other end (10c) of the body section (10a) to the one end (10b) and, together with the first tongue section (12), forms an abutment section (11) by fitting into the fitting groove (12c). The outer peripheral surfaces (12d, 13d) of the first tongue section (12) and the second tongue section (13) are formed in a barrel shape that bulges outwards in the radial direction.