Rotary Compressor Geometry for Leakage and Sliding Loss Balance
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Solution Overview
Problem
Rotary compressors face challenges in achieving optimal balance between mechanical and leakage/heat receiving losses, with high leakage loss between the roller and cylinder, and sliding loss due to crankshaft design, limiting compression efficiency and refrigeration cycle performance.
Innovation Solution
A rotary compressor design that sets specific ratios for the cylinder inside diameter, eccentricity, crankshaft diameter, and sliding length to minimize leakage and sliding losses, with equations H/(φDa•E) ≤ 0.065 and 0.35+0.07•K•H ≤ L/φDb ≤ 0.45+0.07•K•H, ensuring efficient compression and refrigeration cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the cylinder height H is reduced to decrease leakage loss, then leakage loss is decreased, but the cylinder inside diameter φDa or eccentricity E needs to be increased which is limited by the sealed case housing
Solution Approach 1:
The patent applies parameter changes by optimizing the ratio H/(φDa·E) to a specific range (0.04-0.06) and the ratio L/φDb to a specific range (0.30-0.50). This resolves the contradiction by finding optimal parameter values that simultaneously reduce leakage loss while maintaining design feasibility within the sealed case constraints.
2Loss of energy
If the ratio L/φDb is increased to decrease sliding loss, then sliding loss is decreased, but the countershaft diameter φDc must be extremely decreased which sacrifices reliability
Solution Approach 1:
The patent resolves this contradiction by establishing an optimal range for the ratio L/φDb (0.30-0.50) rather than maximizing it. This parameter optimization allows sufficient sliding length to reduce sliding loss while maintaining adequate countershaft diameter for reliability, avoiding the extreme trade-off mentioned in the background.
3Loss of energy
If the value K [H/(φDa•E)] is decreased to improve compression efficiency, then compression efficiency is improved, but the cylinder inside diameter φDa is limited by the outside diameter of sealed case
Solution Approach 1:
The patent resolves this contradiction by optimizing the value of K [H/(φDa·E)] to a specific range (0.04-0.06) rather than minimizing it indefinitely. This optimal parameter range achieves improved compression efficiency while respecting the physical constraint that the cylinder inside diameter cannot exceed the sealed case outside diameter.
Data Source
AI summary
A rotary compressor, which contains a motor unit and compression mechanism in a sealed case, transmits the rotational power of the motor to the compression mechanism through a rotary shaft and crankshafts eccentrically provided in the rotary shaft, and compresses a refrigerant in the compression mechanism, wherein the rotary compressor is configured to have H/(φa•E)=K, and K≦0.065, and the formula 0.35+0.07•K•H≦L/φDb≦0.45+0.07•K•H, assuming that the inside diameter of the cylinder forming the compression mechanism is φDa [mm], the cylinder height is H [mm], the crankshaft eccentricity is E [mm], the crankshaft diameter is φDb [mm], and the sliding lengths of the crankshaft and a roller fitted over the crank are set to L [mm].