Monolithic Crankshaft with Stepped Shaft Section
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Solution Overview
Problem
Existing fluid machines with crankshafts having eccentric sections at both ends require complex assembly processes, increase manufacturing costs, and suffer from reduced strength and performance due to division of the shaft, leading to decentering issues.
Innovation Solution
A monolithic crankshaft design with first and second eccentric sections at respective ends, where the shaft section is interposed between them, allowing for simplified assembly by positioning the eccentric sections' peripheral edges radially inside and outside the shaft section, and setting specific angles between the eccentric and shaft sections to prevent decentering and enhance dynamic balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the crankshaft is divided in the middle of the shaft to insert a motor rotor, then the motor rotor can be assembled into the crankshaft, but the assembly process becomes complicated and work hours increase
Solution Approach 1:
The crankshaft is divided into three sections: a first eccentric section, a shaft section, and a second eccentric section. The shaft section is designed with a larger outer diameter than the eccentric sections, creating a stepped configuration that allows the motor rotor to be assembled onto the shaft section without requiring complex division and reassembly processes
Solution Approach 2:
The motor rotor is nested onto the shaft section of the crankshaft, where the shaft section serves as the mounting base. The stepped configuration allows the motor rotor to be directly assembled onto the larger-diameter shaft section, simplifying the assembly process while maintaining the integrated structure
2Adaptability or versatility
If the crankshaft is divided in the middle of the shaft, then the motor rotor can be inserted, but the strength of the crankshaft is reduced
Solution Approach 1:
The first eccentric section, shaft section, and second eccentric section are formed as a single integrated monolithic crankshaft structure. This merging of sections maintains the full strength of the crankshaft while providing a dedicated shaft section for motor rotor assembly, avoiding the strength reduction that would occur with separate assembled components
Solution Approach 2:
The crankshaft employs a composite structural design where different sections serve different functions: the eccentric sections for compression/expansion mechanisms and the larger-diameter shaft section for motor rotor mounting. This composite structure optimizes both strength and adaptability without requiring material compromises
3Adaptability or versatility
If the crankshaft is divided in the middle of the shaft, then the motor rotor can be assembled, but decentering occurs and performance is reduced
Solution Approach 1:
The crankshaft features an asymmetric stepped configuration where the shaft section has a larger outer diameter than the eccentric sections. This asymmetric design creates a natural mounting surface for the motor rotor that ensures proper centering and alignment, preventing decentering issues while allowing motor rotor assembly
Data Source
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AI summary
A crankshaft is to be provided that allows its assembly process to be simplified, work hours required for the assembly process to be shortened and a manufacturing cost to be reduced. The crankshaft (11) is provided with first eccentric section (11a) and second eccentric section at respective ends while interposing a shaft section (11b) therebetween and has such a shape that a peripheral edge of the first eccentric section (11a) and/or the second eccentric section is positioned radially inside of a peripheral edge of the shaft section (11b).