Ceramic Bearing Scroll Compressor for Low-Lubricity Refrigerant Oil
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Solution Overview
Problem
Conventional lubrication systems for compact scroll compressors face challenges due to size constraints, making it difficult to incorporate traditional lubrication methods, particularly in refrigerant compressors where refrigerant-oil mixtures provide inadequate lubrication, leading to reduced bearing life and efficiency.
Innovation Solution
The use of ceramic rolling elements and polymeric cages in combination with a refrigerant-oil solution for lubrication, along with optimized surface finishes and low viscosity lubrication, enhances lubrication efficiency and bearing life in compact scroll compressors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lubrication systems are used in compact scroll compressors, then the compressor can be manufactured with traditional methods, but the lubrication efficiency is insufficient and bearing life is reduced
Solution Approach 1:
The patent changes the material parameter of the rolling elements from conventional steel to ceramic materials. This material parameter change enables the bearing to operate effectively with refrigerant-oil solution lubrication, improving lubrication efficiency and bearing life without adding system complexity
Solution Approach 2:
The patent uses composite material construction for the bearing components, specifically ceramic rolling elements combined with polymeric cages. This composite approach provides both the hardness needed for durability and the self-lubricating properties necessary for effective operation with low-viscosity refrigerant-oil solution
2Volume of moving object
If the compressor size is reduced to make it compact, then the compressor becomes more suitable for various applications, but conventional lubrication systems become difficult to incorporate
Solution Approach 1:
The bearing components are designed to self-lubricate using the refrigerant-oil solution naturally present in the compressor system. The polymeric cage material and ceramic rolling elements work together to retain and distribute the lubricant, eliminating the need for separate lubrication delivery mechanisms and simplifying the compact design
3Reliability
If refrigerant-oil mixture is used for lubrication, then the necessary lubrication is provided in compact compressors, but the lubrication efficiency is poor leading to reduced bearing life
Solution Approach 1:
The patent changes the material parameters of the bearing components - using ceramic rolling elements with high hardness and low density, combined with polymeric cages having appropriate friction coefficients. These parameter changes enable effective lubrication with refrigerant-oil solution, improving both lubrication efficiency and bearing life
Solution Approach 2:
The patent applies different material qualities to different parts of the bearing - ceramic material for rolling elements requiring hardness and lubricity, polymeric material for cages requiring friction management and lubricant retention. This local quality differentiation optimizes the overall bearing performance with refrigerant-oil solution lubrication
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 improves lubrication conditions, reduces friction, and increases bearing life by mitigating the effects of poor lubrication and contamination, thereby enhancing the operational efficiency and reliability of compact scroll compressors.
Implementation Method 1
a quantity of a solution formed of refrigerant and oil is disposed within the housing chamber, the solution being directed into the drive bearing to lubricate the at least one ceramic rolling element
Implementation Method 2
The drive bearing includes at least one row of rolling elements disposed between the shaft eccentric end portion and the scroll member, at least one of the rolling elements being formed of a ceramic material
Data Source
AI summary
A scroll compressor includes a housing and a rotatable drive shaft disposed within the housing and having an eccentric end portion. First and second support bearings rotatably couple the drive shaft with the housing and each includes a plurality of rolling elements, at least one of which is ceramic, and an annular cage formed of a polymeric material. A scroll member is disposed within the housing chamber and a drive bearing rotatably couples the shaft eccentric portion with the scroll member such that the scroll member orbits about the central axis. The drive bearing includes a plurality of rolling elements, at least one of which is ceramic, and an annular cage formed of a polymeric material. Further, a solution formed of refrigerant and oil is directed to each one of the drive bearing and the first and second support bearings so as to lubricate the rolling elements.