Rotary Compressor Drive Shaft Coupling Reinforcement
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Solution Overview
Problem
Rotary compressors with increased eccentricity face challenges in preventing warpage of the drive shaft due to reduced diameter, which affects piston assembly and compressor efficiency.
Innovation Solution
The design incorporates a coupling portion with a reinforcement portion on the drive shaft, ensuring the outer surface does not extend beyond the eccentric portion's radial direction, and includes intermediate reinforcement portions to maintain structural integrity and prevent warpage, allowing for increased eccentricity without diameter increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the eccentricity is increased while maintaining the diameter of the eccentric portion, then the capacity is increased without increasing sliding loss, but the outer surface of the drive shaft becomes recessed causing the piston to be unable to attach to the eccentric portion
Solution Approach 1:
The patent introduces a radial dimension solution by providing a coupling portion with a larger radius than the recessed eccentric portion. This allows the piston to attach to the coupling portion in the radial direction rather than being constrained by the axial recess, resolving the assembly difficulty while maintaining increased eccentricity for higher capacity
Solution Approach 2:
The coupling portion acts as an intermediary element between the piston and the eccentric portion. It provides a suitable attachment surface for the piston while being connected to the drive shaft, enabling the piston to be properly assembled despite the recessed outer surface of the eccentric portion
2Ease of operation
If the outer surface of the main shaft portion adjacent to the eccentric portion is cut out to allow piston assembly, then the piston can be fitted to the eccentric portion, but the diameter of the drive shaft becomes small resulting in large warpage
Solution Approach 1:
The patent applies local quality by providing the coupling portion with a larger radius only at the specific location where piston assembly is needed, while maintaining the overall drive shaft diameter and strength. This localized structural modification enables piston attachment without compromising the global structural integrity and warpage resistance of the drive shaft
Solution Approach 2:
The drive shaft is segmented into distinct functional portions: the eccentric portion for capacity enhancement, the coupling portion for piston assembly, and the main shaft portion for structural strength. This segmentation allows each portion to be optimized for its specific function without compromising the overall system
Data Source
AI summary
A rotary compressor includes a first cylinder, a first piston and a drive shaft. The drive shaft includes a first eccentric portion, a first shaft portion rotatably supported by a first bearing, and a first coupling portion coupling the first shaft portion with the first eccentric portion. The first piston is fitted to the first eccentric portion. The first shaft portion has a cylindrical shape coaxial with the rotational center axis. Re1−e1<R1. Re1 is a radius of the first eccentric portion. R1 is a radius of the first shaft portion. e1 is an eccentricity of the first eccentric portion. An outer surface of the first coupling portion does not extend radially out of an outer surface of the first eccentric portion. The first coupling portion includes a reinforcement portion with an outer surface positioned radially outside an outer surface of the first shaft portion.