Oil Scraper Ring Structure for Pistons Without Drain Bores
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Solution Overview
Problem
Existing oil scraper rings for pistons without oil drain bores face challenges in effectively distributing and scraping excess oil, leading to potential oil film weakening and insufficient lubrication, particularly in steel pistons which are cost-intensive to manufacture with drainage ducts.
Innovation Solution
The oil scraper ring design features radial oil passages and grooves on the lower ring flank, allowing oil to flow from the collecting groove into the gap between the piston and cylinder, eliminating the need for oil drain bores and ensuring consistent oil distribution without tearing the oil film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If oil drain bores are provided in the piston for steel pistons, then oil drainage is effective, but manufacturing cost increases significantly
Solution Approach 1:
The invention extracts the oil drainage function from the piston structure by providing oil drain openings in the piston ring groove instead of drilling through the entire piston. This allows oil to be drained laterally from the groove without compromising the piston's structural integrity or requiring complex internal ducts, thereby reducing manufacturing cost while maintaining drainage effectiveness
Solution Approach 2:
The invention introduces an intermediary structure - the oil drain openings in the piston ring groove - that mediates between the oil scraper ring and the oil pan. This intermediary allows oil to flow from the scraper ring region laterally into the oil pan without requiring direct vertical drainage paths through the piston, thus achieving effective drainage with simpler manufacturing
2Ease of operation
If oil is scraped off the upper rail during downward piston movement, then excess oil is removed from the cylinder wall, but oil accumulates between the rails and must be discharged
Solution Approach 1:
The invention segments the oil drainage path into two parts: oil passages that collect oil from between the scraper rails and transport it to the rear side of the ring, and grooves on the lower ring flank that discharge it laterally. This segmentation allows efficient oil removal without accumulation while maintaining the scraping function
Solution Approach 2:
The invention changes the drainage dimension by adding grooves on the lower ring flank that enable lateral oil discharge in addition to the radial oil passages. This multi-dimensional drainage approach prevents oil accumulation between the rails while maintaining effective scraping operation
3Reliability
If oil is transported only underneath the piston rings, then the oil film between piston and cylinder is not weakened, but oil distribution to the cylinder wall may be insufficient
Solution Approach 1:
The invention applies local quality by providing grooves at specific locations on the lower ring flank where oil discharge is most beneficial. This localized oil discharge ensures adequate lubrication at critical areas while maintaining the overall oil film integrity underneath the piston rings
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
This design enhances oil scraping efficiency, prevents oil film tearing, and maintains optimal lubrication, reducing friction and improving thermodynamic efficiency in pistons made of steel or aluminum, while being cost-effective to manufacture.
Implementation Method 1
the ring thereby has intermediate pieces, which are distributed over the circumference and which are held at a distance, which are dimensioned in the radial direction so that an oil collecting chamber is formed below the rail
Implementation Method 2
Oil passages running in the radial direction are furthermore arranged in a region between the upper scraper rail and the lower scraper rail
Data Source
AI summary
An oil scraper ring is provided for pistons (2) of an internal combustion engine having an oil scraper piston ring groove (4) formed without at least one oil drain bore. The scraper ring includes a ring body (6) comprising an upper ring flank (8), a lower ring flank (10), a ring inner side (12), a ring outer side (14) and two abutting surfaces (16, 18). An upper oil scraper rail (20) and a lower oil scraper rail (22) extend in the circumferential direction in spaced apart relation from one another in the axial direction and extend radially to the outside from the ring outer side (14) are arranged on the ring outer side (14). Oil passages (24) running in the radial direction are arranged in a region between the upper scraper rail (20) and the lower scraper rail (22), and at least one groove (26) extends in the radial direction on the lower ring flank (10).