Refrigerant compressor and freezer including same
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Solution Overview
Problem
Refrigerant compressors face efficiency deterioration due to high frictional resistance and lubrication issues, particularly with the reduction in lubricating oil viscosity and sliding portion dimensions, leading to increased input and reduced performance, especially during low-speed operations.
Innovation Solution
A refrigerant compressor design featuring a shaft part with a sliding surface coated by an oxide film having hardness equal to or greater than the bearing part, and a curved-surface portion on the bearing part to reduce local contact and maintain oil film thickness, combined with a bell mouth or crowning on the bearing surface to enhance contact area and reduce surface pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the viscosity of lubricating oil is lowered and dimensions of sliding portions are shortened to improve efficiency, then power consumption is reduced, but the oil film becomes thin and contact between sliding portions increases leading to higher input
Solution Approach 1:
The invention changes the physical-chemical parameters of the sliding surfaces by forming oxide films with specific hardness values (HV 400-900) through controlled oxidation treatment. This modifies the surface properties to reduce friction and maintain stable lubrication conditions even with lower viscosity oil and shorter dimensions
Solution Approach 2:
The invention creates a composite structure consisting of the base metal material and an oxide film layer on the sliding surfaces. This composite structure combines the mechanical strength of the base material with the low-friction properties of the oxide film, achieving both energy efficiency and reliable lubrication
2Strength
If a hard soft-nitriding-treated film is provided on the sliding portion to reduce abrasion, then the film coats the projections and slows down abrasion progress, but the high input state continues for a long period causing efficiency deterioration
Solution Approach 1:
The invention changes the surface hardness parameter by forming oxide films with controlled hardness (HV 400-900) that is harder than the bearing sliding surface. This creates optimal friction characteristics that reduce initial input while maintaining abrasion resistance
Solution Approach 2:
The invention creates a surface layer that copies or replicates the ideal friction characteristics needed for low input operation. The oxide film surface structure mimics the properties of low-friction materials while being applied to the actual sliding components
3Productivity
If the main shaft rotates relative to the main bearing, then the compressor operates, but large frictional resistance force is generated between the sliding portions increasing input
Solution Approach 1:
The invention changes the surface properties of the sliding portions by forming oxide films that reduce the coefficient of friction. This allows the compressor to operate with significantly reduced frictional resistance between the main shaft and main bearing
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 effectively suppresses the decrease in oil film thickness and breakage, maintaining compressor efficiency and reducing initial input, thereby ensuring long-term reliability and low power consumption.
Implementation Method 1
A film having hardness equal to or more than hardness of a sliding surface of the bearing part is provided on a sliding surface of the shaft part
Implementation Method 2
the sliding surface of the bearing part includes a curved-surface portion having an inner diameter that continuously increases in a curved shape toward an end of the bearing part
Data Source
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AI summary
The present invention includes: an electric component; a compression component driven by the electric component to compress a refrigerant; and a sealed container accommodating the electric component and the compression component. The compression component includes: a shaft part rotated by the electric component; and a bearing part slidingly contacting the shaft part such that the shaft part is rotatable. A film having hardness equal to or more than hardness of a sliding surface of the bearing part is provided on a sliding surface of the shaft part. The sliding surface of the bearing part includes a curved-surface portion having an inner diameter that continuously increases in a curved shape toward an end of the bearing part in a center axis direction of the bearing part, or the sliding surface of the shaft part includes a curved-surface portion having an outer diameter that continuously decreases in a curved shape toward an end of the shaft part in a center axis direction of the shaft part.