Recessed Oil Retention Regions in Rotary Compressor Seals
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Solution Overview
Problem
In rotary compressors, the sealing property of the compression chamber by the oil film deteriorates due to the difficulty in forming an oil film in small gaps, leading to reduced compression efficiency, especially during downsizing.
Innovation Solution
The rotary compressor incorporates an oil-film retention region on the piston and end plates with recessed portions to retain lubricating oil, enhancing the sealing property and compression efficiency by maintaining an appropriate oil film over the circumferential direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the compression unit is downsized to reduce gaps between piston and end plates, then the compression unit size is reduced, but the oil film formation becomes difficult and sealing property deteriorates
Solution Approach 1:
The invention applies local quality by creating recessed portions at specific locations on the piston and end plates where oil film formation is critical. These recessed portions have different geometries (depths, diameters, arrangements) tailored to local requirements for oil retention, allowing effective sealing in downsized compressors without compromising overall compression unit size.
2Productivity
If the gap between piston and end plate is reduced to increase compression efficiency, then the compression efficiency increases, but the oil film cannot be properly formed leading to deteriorated sealing
Solution Approach 1:
The recessed portions are designed to preliminarily accumulate lubricating oil before the compression cycle begins. This preliminary action of oil accumulation in the recessed portions ensures that an adequate oil film is already present when the piston contacts the end plate, maintaining sealing property even when the gap is reduced for higher compression efficiency.
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 oil-film retention region effectively enhances the sealing property and increases the compression efficiency of the compression chamber, even in downsized units, by stabilizing the oil film and reducing refrigerant gas leakage.
Implementation Method 1
an array of a plurality of recessed portions that are configured to retain lubricating oil
Implementation Method 2
a compression unit that compresses the refrigerant... sealed by an oil film of lubricating oil, which adheres to the vane and the piston
Data Source
AI summary
A compression unit of a rotary compressor includes a cylinder, an upper end plate that closes the upper side of the cylinder, a lower end plate that closes the lower side of the cylinder, and a piston that is fitted to a rotating shaft, revolves along an inner peripheral surface of the cylinder, and forms a cylinder chamber in the cylinder. At least one of an end face of the piston in the axial direction of the rotating shaft, a sliding surface of the upper end plate that slides with the end face of the piston, and a sliding surface of the lower end plate that slides with the end face of the piston, has formed therein an oil-film retention region having an array of a plurality of recessed portions that retain lubricating oil.