Rotary Compressor Crankshaft Connecting Part Rigidity
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Solution Overview
Problem
Multi-cylinder rotary compressors face challenges in reducing the diameter of crankshafts to minimize friction loss and increasing the eccentricity of crankshafts to decrease sliding loss, while maintaining the reliability and rigidity of the connecting parts, which are crucial for efficient refrigeration cycle performance.
Innovation Solution
The compressor design incorporates a rotary shaft with main and countershafts, crankshafts, and connecting parts, where the radius of the crankshaft is less than the sum of the main shaft and eccentricity, and the connecting parts have specific cross-sectional shapes to facilitate roller fitting and enhance rigidity, allowing for reduced axial length and increased reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the diameter of the crankshaft is decreased to reduce friction loss, then energy efficiency is improved, but the strength and rigidity of the connecting part deteriorate
Solution Approach 1:
The connecting part employs a variable cross-sectional area design where the area is larger at the crankshaft connection end and smaller at the opposite end. This local quality variation allows the connecting part to maintain sufficient strength at the critical crankshaft connection point while reducing overall material usage and weight, thereby resolving the contradiction between reducing friction loss through smaller crankshaft diameter and maintaining connecting part strength.
2Loss of energy
If the eccentricity of the crankshaft is increased to decrease sliding loss, then energy efficiency is improved, but the complexity of the connecting part increases
Solution Approach 1:
The connecting part is designed with dynamic adaptability through its asymmetric cross-sectional configuration, allowing it to effectively handle the increased dynamic loads resulting from higher crankshaft eccentricity. The variable cross-sectional area provides the necessary flexibility and strength distribution to manage the complex stress patterns without requiring additional complex structural elements.
3Volume of moving object
If the axial length of the connecting part is decreased to compact the compressor, then the size of the compressor is reduced, but the rigidity of the connecting part deteriorates
Solution Approach 1:
The connecting part utilizes localized cross-sectional area variation, with the larger area positioned at the crankshaft connection end, to maximize rigidity in the most critical region while minimizing the axial length of the connecting part. This allows the compressor to achieve a compact size without sacrificing the necessary rigidity at the connection point through strategic placement of material where it is most needed.
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
This configuration reduces sliding loss, enhances compression efficiency, and improves the reliability of the compressor, leading to improved refrigeration cycle performance and efficiency.
Implementation Method 1
crankshafts which are eccentrically provided between the main shaft and countershaft, fitted with rollers, and a connecting part connecting the crankshafts. The crankshafts and rollers are housed eccentrically rotatable in a cylinder chamber formed inside a cylinder.
Data Source
AI summary
A rotary compressor, in which formulas Rc<Rm+e and RC≧Rs+e are established, when the radius of a main shaft is Rm, the radius of a countershaft is Rs, the radius of a crankshaft is Rc, and the eccentricity is e, a connecting part has a A-periphery which is formed on the counter-eccentric side periphery of the second crankshaft, and a B-periphery formed on the counter-eccentric side periphery of a first crankshaft, and a formula H>L≧H−Cr−Cs is established, when the axial direction of the connecting part is L, the axial length of the first roller is H, the axial length of a bevel formed at the inside edge of the first roller is Cr, and the axial direction of a bevel of the second crankshaft is Cs.