Impeller-Integrated Bearing Assembly for Lower Rotor Loading
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Solution Overview
Problem
Rotor assemblies in compressors often experience imbalance due to component wear and thermal distortion, leading to increased loading on bearings and reduced lifespan, as complete balancing before assembly is not always feasible.
Innovation Solution
A rotor assembly design where the bearing assembly is located at least partly within the profile of the centrifugal impeller, comprising a hub with a recess to house a pair of spaced bearings, reducing cantilever length and radial loading, and allowing securement over a large surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the bearing assembly is located outside the impeller profile, then the rotor assembly can be easily assembled, but the bearing loading increases and lifespan decreases
Solution Approach 1:
The bearing assembly is nested within the impeller profile, specifically positioned inside the hub structure. This nesting arrangement reduces the cantilever length and brings the bearing closer to the impeller's center of mass, thereby reducing radial loading and extending bearing lifespan while maintaining assembly feasibility through integrated hub design
2Device complexity
If the bearing assembly is located far from the impeller center of mass, then the assembly is simpler, but the cantilever length increases and rotor stiffness decreases
Solution Approach 1:
The hub structure is designed with differentiated local zones: an inner region for shaft mounting, a middle region containing the bearing assembly positioned near the center of mass, and an outer region for blade attachment. This local quality differentiation optimizes the bearing position to reduce cantilever length and enhance rotor stiffness without complicating the overall assembly process
3Device complexity
If the bearing assembly uses a single bearing, then the structure is simpler, but the support stability is insufficient
Solution Approach 1:
The bearing assembly is segmented into a pair of spaced bearings rather than using a single bearing. This segmentation provides distributed support points along the shaft, enhancing rotor support stability and reducing point loads on individual bearings, while the modular nature of the segmented design keeps the overall structure manageable
Data Source
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AI summary
A rotor assembly (1) comprising a shaft (2) to which are mounted an impeller (3) and a bearing assembly (4), wherein the bearing assembly (4) is located at least partly within the profile of the impeller (3).