Curved Oil Scraper Ring Profile for Uniform Scraping and Oil Deflection
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Solution Overview
Problem
Existing oil scraper rings face challenges in achieving uniform scraping properties and efficient oil conveyance, particularly in the direction of the groove base, with current designs relying on slots and openings between scraper webs, which are not optimal for improved performance.
Innovation Solution
A three-part oil scraper ring design featuring two ring bodies with distinct flanks and a radially curved outer surface, where the radius of curvature is smaller than the height by a factor of 1.5 to 6, and transitions between the curvature and flanks are convex and spiral, allowing for improved oil deflection towards the groove base during piston movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If slots and openings are provided between scraper webs to convey oil, then oil conveyance is improved, but the scraping uniformity deteriorates
Solution Approach 1:
The scraper ring is divided into multiple scraper webs (typically two or more) with openings between them, allowing oil to be conveyed through the ring while maintaining scraping functionality. This segmentation enables simultaneous oil passage and scraping action.
Solution Approach 2:
Different regions of the scraper ring are given different properties: the outer circumference has a specific radius of curvature for uniform scraping, while the inner region contains openings for oil conveyance. This local differentiation allows each region to optimize its specific function.
2Reliability
If the radius of curvature of the running surface is reduced, then contact uniformity is improved, but the ring height must be increased proportionally
Solution Approach 1:
The running surface of the scraper ring is designed with a specific radius of curvature (R) that is smaller than the half-height of the ring, creating a curved contact surface that matches the cylinder bore geometry. This curvature ensures uniform contact pressure distribution across the contact area.
Solution Approach 2:
The patent specifies precise parameter relationships: the radius of curvature R should be between 0.06-0.12mm while ring height H is between 0.28-0.52mm, giving a ratio R/H between 0.11-0.22. This parameter optimization achieves contact uniformity without excessive ring height.
3Productivity
If the ring height is increased to achieve better scraping, then scraping efficiency is improved, but friction losses increase
Solution Approach 1:
The scraper ring height is optimized to provide sufficient scraping action without being excessive. The height is carefully controlled (0.28-0.52mm) to achieve the minimum required for effective oil scraping while avoiding unnecessary friction from excessive contact area.
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 enhances scraping efficiency by ensuring uniform contact and effective oil deflection, reducing oil consumption and friction losses, while preventing oil accumulation and coke formation, and maintaining optimal performance in both upward and downward piston movements.
Implementation Method 1
two ring bodies (4, 4') which are held at a distance in the axial direction by a spring (3, 3') in order to be pressed outwards in the radial direction
Implementation Method 2
held at a distance in the axial direction by a spring (3, 3') in order to be pressed outwards in the radial direction
Data Source
AI summary
A three-part oil scraper ring includes an expander spring and two scraper rings, comprising a ring body (4) having an upper flank (6), a lower flank (8), a ring inner surface (10) and a ring outer surface (12) which has a ring outer contour (14) in cross-section in axial direction (A). The ring body (4) has a height H which corresponds to the greatest distance of the upper flank (6) to the lower flank (8). The ring outer contour (14) forms a running surface (16) which has a radius of curvature R which is smaller than the height H of the scraper ring (2) by a factor between 1.5 to 6, preferably between 3 to 5 and further preferably between 3.5 to 4.5.