Refrigerating Machine Oil Copolymer for High-Speed Sliding Friction
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Solution Overview
Problem
Conventional refrigerating machine oils fail to effectively reduce friction in lubrication regions with high sliding speeds, leading to increased metal-to-metal contact and insufficient compressor efficiency improvement.
Innovation Solution
A refrigerating machine oil composition comprising a lubricating base oil, preferably mineral oil, and a copolymer containing unsaturated carboxylic acid ester monomer units, along with optional hydrocarbon base oils, is used to enhance low friction characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the viscosity of the refrigerating machine oil is lowered, then friction in the fluid lubrication region is reduced, but friction in the elastic fluid lubrication region, mixed lubrication region, and boundary lubrication region increases due to increased metal-to-metal contact
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the refrigerating machine oil. Specifically, it uses a copolymer with a number average molecular weight of 1,000 to 10,000 and a specific composition ratio of monomer units (50-90 mol% of first monomer, 10-50 mol% of second monomer) to optimize lubrication performance across different lubrication regions while maintaining appropriate viscosity characteristics
Solution Approach 2:
The patent employs composite materials by creating a copolymer composed of two different monomer units with specific functional characteristics. The first monomer unit provides certain lubrication properties while the second monomer unit complements it, creating a synergistic effect that reduces friction across multiple lubrication regions including elastic fluid, mixed, and boundary lubrication regions
2Force
If conventional refrigerating machine oil is used to reduce friction in boundary lubrication region, then some friction reduction is achieved, but compressor efficiency improvement remains insufficient
Solution Approach 1:
The patent changes the molecular weight parameter of the copolymer to a specific range (1,000 to 10,000 number average molecular weight) and adjusts the compositional parameters (monomer unit ratios) to achieve optimal friction reduction characteristics that directly translate to improved compressor efficiency, rather than merely reducing friction coefficient in isolation
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 composition achieves reduced friction coefficients even in lubrication regions with high sliding speeds, improving compressor efficiency and lubrication performance.
Implementation Method 1
The refrigerating machine oil lubricates sliding members such as a connecting rod and a piston, and reduces friction in lubrication regions including elastic fluid lubrication region, mixed lubrication region, and boundary lubrication region
Data Source
Figure 1
AI summary
An aspect of the present invention provides a refrigerating machine oil containing: a lubricating base oil; and a polymer containing an unsaturated carboxylic acid ester as a monomer unit, wherein the unsaturated carboxylic acid ester contains an ester of an unsaturated carboxylic acid and an alcohol having a hydrocarbon group represented by the following formula (1): wherein x represents an integer of 5 to 18, and y represents an integer of 3 to 18.