Oil Control Ring Grooved Seating Tabs Prevent Side Rail Rotation
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Solution Overview
Problem
Existing oil control rings face challenges in preventing the separate rotation of side rails while maintaining wear resistance and sludge resistance, particularly due to the degradation of engine-lubricating oil leading to oil sludge that causes sticking and excessive lubricating oil consumption.
Innovation Solution
A combined oil control ring design featuring a pair of circular side rails with longitudinally extending grooves on the seating tabs and a nitride layer, where the depth and thickness of the grooves and nitride layer meet specific conditions to prevent separate rotation, and a metal coating on the spacer expander and side rails for enhanced wear and sludge resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a nitride layer is formed on seating tabs of a spacer expander to improve wear resistance, then wear resistance is improved, but side rails become easily rotatable separately in circumferential direction
Solution Approach 1:
The seating tab is segmented by forming grooves that divide the contact surface into multiple regions. This segmentation increases the number of contact points with side rails, thereby increasing friction resistance and preventing separate rotation while maintaining wear resistance through the nitride layer.
Solution Approach 2:
The nitride layer is applied locally on the seating tabs rather than uniformly across the entire spacer expander. This localized treatment provides wear resistance precisely where needed at the contact points with side rails, while the grooves create local variations in surface topology to enhance friction and prevent rotation.
2Reliability
If surface roughening or projections are formed on seating tabs to prevent separate rotation of side rails, then separate rotation is prevented, but manufacturing complexity increases
Solution Approach 1:
Instead of creating complex three-dimensional projections, the invention changes the surface parameter by forming grooves with specific depth, width, and spacing. This parameter-based approach achieves enhanced friction resistance through controlled surface topology that is simpler to manufacture while effectively preventing side rail rotation.
3Productivity
If combustion temperature is elevated or direct injection is used to improve combustion efficiency, then combustion efficiency is improved, but engine-lubricating oil degrades forming sludge
Solution Approach 1:
The invention converts the harmful effect of oil sludge into a beneficial outcome by designing the spacer expander structure to actively manage sludge accumulation. The grooves on seating tabs control oil flow and sludge distribution, preventing sludge from causing sticking while allowing the high-temperature combustion benefits to be maintained.
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 design effectively prevents the separate rotation of side rails, reduces wear, and minimizes oil consumption, while maintaining excellent wear and sludge resistance, thereby improving fuel efficiency and reducing oil sludge accumulation.
Implementation Method 1
a nitride layer is formed on the seating tabs
Implementation Method 2
one or more grooves extending substantially longitudinally are formed on a seating tab
Data Source
AI summary
A combined oil control ring comprising a pair of circular side rails each having a gap, and a spacer expander longitudinally sandwiched by the side rails, which has seating tabs for pushing inner surfaces of the side rails on the inner side, a side rail-pushing surface of each seating tab being provided with one or more grooves extending substantially longitudinally; each of the side rail-pushing surfaces including the grooves being provided with a nitride layer, and the depth d (μm) of the grooves, the surface hardness h (micro-Vickers hardness HV0.1) of the nitride layer, and the thickness t (μm) of the nitride layer having micro-Vickers hardness HV0.1 of 700 or more meeting the relation of the0.05≦1000×d/(h×t)≦0.45 (1).