Rotary Compressor Piston Gap Optimization
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Solution Overview
Problem
Conventional rotary compressors face challenges in maintaining efficiency due to machining difficulties of non-circular cylinder cross sections, which affect precision and lead to variations in performance, and struggle to balance leakage and sliding losses.
Innovation Solution
The rotary compressor design includes a hermetic container with a compression mechanism featuring a piston and vane that partitions the compression chamber into low and high pressure portions, with strategically set gaps to minimize leakage while preventing sliding losses, by positioning the eccentric portion and upper bearing to create balanced gaps at specific crank angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the operation-time minimum gap W between piston outer peripheral surface and cylinder inner peripheral surface is set greater, then sliding loss is reduced and seizing or wearing is prevented, but leakage loss increases and compressor efficiency deteriorates
Solution Approach 1:
The patent pre-establishes a minimum gap W between the piston outer peripheral surface and cylinder inner peripheral surface during the design and assembly phase. This gap is calculated and set in advance to ensure it never becomes zero during operation, preventing seizing before it occurs while maintaining efficiency by optimizing the gap size to minimize leakage loss.
Solution Approach 2:
The patent optimizes the value of the minimum gap W as a critical parameter. By carefully selecting and controlling the gap dimension, the patent achieves a balance between preventing contact (seizing prevention) and minimizing leakage. The gap W is set to a specific optimal value that resolves the contradiction between reliability and energy loss.
2Loss of energy
If the operation-time minimum gap W is set smaller, then leakage loss is reduced, but sliding loss increases and seizing or wearing occurs
Solution Approach 1:
The patent pre-establishes a minimum gap W between the piston outer peripheral surface and cylinder inner peripheral surface during the design and assembly phase. This gap is calculated and set in advance to ensure it never becomes zero during operation, preventing seizing before it occurs while maintaining efficiency by optimizing the gap size to minimize leakage loss.
Solution Approach 2:
The patent optimizes the value of the minimum gap W as a critical parameter. By carefully selecting and controlling the gap dimension, the patent achieves a balance between preventing contact (seizing prevention) and minimizing leakage. The gap W is set to a specific optimal value that resolves the contradiction between reliability and energy loss.
3Loss of energy
If a non-circular cross section shape is used for the cylinder, then machining precision requirements increase, but leakage loss can be reduced
Solution Approach 1:
The patent optimizes the value of the minimum gap W as a critical parameter. By carefully selecting and controlling the gap dimension, the patent achieves a balance between preventing contact (seizing prevention) and minimizing leakage. The gap W is set to a specific optimal value that resolves the contradiction between reliability and energy loss.
Data Source
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AI summary
If a gap formed between an outer peripheral surface of a piston and an inner peripheral surface of a cylinder in a state where an eccentric portion is disposed at a position of a predetermined crank angle from a position of a vane and the piston is made to abut against a most eccentric position of the eccentric portion and an inner peripheral surface of an upper bearing is made to abut against a main shaft outer peripheral surface of the crankshaft when a rotary compressor is assembled is defined as ´, a minimum value ´min of the gap ´ is set at a crank angle substantially opposite from a maximum load direction of the crankshaft during operation of the rotary compressor.