Compressor Driveshaft Assembly for High-Speed Impeller Alignment
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Solution Overview
Problem
Centrifugal compressors face challenges in maintaining friction fit connections and alignment of components at high-rotational speeds, leading to vibrations and premature failures due to eccentric loads and centrifugal forces.
Innovation Solution
A driveshaft assembly with a thrust disk and impeller design that uses friction or press fits, combined with alignment features and centrifugal force management, ensures co-axial alignment and maintains friction connections even at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If components are separately coupled to the driveshaft using friction fit connections, then the assembly is simple and easy to manufacture, but the centrifugal force at high rotational speeds loosens the friction fit connections, causing misalignment and vibrations
Solution Approach 1:
The patent combines the thrust disk and impeller into a single integrated component that is separately coupled to the driveshaft. This merging allows the component to function as both a thrust bearing support and an impeller, simplifying the assembly process while maintaining secure attachment through the separate coupling approach
Solution Approach 2:
The patent introduces a separate coupling mechanism (such as a key, spline, or other intermediate element) between the driveshaft and the integrated thrust disk-impeller component. This intermediary element provides a positive mechanical connection that prevents loosening under centrifugal force while maintaining the simplicity of separate coupling for assembly purposes
2Productivity
If the compressor operates at higher rotational speeds to process higher volumes of refrigerant, then the cooling capacity increases, but the centrifugal force increases, loosening friction fit connections and creating eccentric loads
Solution Approach 1:
The patent converts the harmful centrifugal force into a beneficial effect by designing the integrated thrust disk-impeller component and its coupling mechanism to utilize centrifugal force for maintaining tight contact and alignment. The separate coupling with positive mechanical engagement ensures that centrifugal force enhances rather than diminishes the connection stability, allowing high-speed operation to achieve higher refrigerant processing volumes without the detrimental loosening effects
3Reliability
If tight tolerances and high manufacturing accuracy are used for the driveshaft assembly, then the alignment and friction fit connections are maintained at high speeds, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the coupling parameter from a friction-based connection (which requires tight tolerances) to a positive mechanical connection through separate coupling mechanisms. This parameter change allows for broader tolerance ranges while maintaining reliable alignment and connection stability at high rotational speeds, reducing manufacturing complexity and cost
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
The assembly maintains component alignment and friction fit connections, reducing vibrations and extending operational lifespan, lowering maintenance costs and wear.
Implementation Method 1
components, such as the impeller and the thrust disk, are separately coupled to the driveshaft using friction fit connections
Implementation Method 2
The driveshaft, impeller, and the thrust disk, rotating at high-rotational speeds, induce centrifugal forces which increase with increased rotational speed
Data Source
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AI summary
A compressor system includes a compressor housing and a driveshaft rotatably supported within the compressor housing. The compressor system further includes an impeller that imparts kinetic energy to incoming refrigerant gas upon rotation of the driveshaft, a thrust disk coupled to the driveshaft, and a bearing assembly mounted to the compressor housing. The impeller includes an impeller bore having an inner surface, and the thrust disk includes an outer disk and a hub. The bearing assembly rotatably supports the outer disk of the thrust disk. The hub is disposed within the impeller bore, and includes a hub outer surface in contact with the inner surface of the impeller bore. A first contact force between the hub outer surface and the inner surface of the impeller bore increases with increased rotational speed of the driveshaft.