Turbomachine Bearing Support Stiffness Tuning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing centering spring assemblies in turbomachines face challenges in adjusting stiffness due to constrained axial distances and difficulty in providing lubrication, especially during oil-interruption events.
Innovation Solution
A centering spring assembly design featuring a damper beam radially outside the bearing support, with radial flanges extending from both ends and a spanner nut that directly contacts the bearing race, incorporating a lubrication trough to capture and retain lubricant, and a continuous piece configuration that includes a bearing race and damper beam for enhanced support and lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the axial length of the beam-like feature is limited, then the axial distance constraint is satisfied, but the tunability of the centering spring is reduced
Solution Approach 1:
The patent transitions from axial length adjustment to radial length adjustment for achieving stiffness tuning. The beam-like features are extended in the radial direction rather than the axial direction, allowing the same centering spring to achieve variable stiffness without increasing axial distance. This dimensional change resolves the contradiction by providing tunability through radial extension while maintaining constrained axial dimensions.
2Length of moving object
If the axial distance is constrained, then the compact design is achieved, but the ability to provide oil to bearings during oil-interruption-event is compromised
Solution Approach 1:
The patent incorporates a lubrication reservoir that pre-stores lubricant before an oil-interruption event occurs. This preliminary action ensures that when oil supply is interrupted, the bearing assembly can continue to receive lubrication from the pre-stored reservoir, maintaining reliability without requiring increased axial distance for alternative lubrication systems.
Solution Approach 2:
The lubrication reservoir acts as an intermediary between the main oil supply system and the bearing assembly. During normal operation, it receives and stores lubricant; during oil-interruption events, it serves as a backup supply source, ensuring continuous lubrication to the bearings without compromising the compact axial design.
3Adaptability or versatility
If multiple circumferentially distributed beam-like features are used, then the stiffness can be adjusted, but the device complexity increases
Solution Approach 1:
The patent combines multiple beam-like features into a single integrated centering spring assembly where the beams are circumferentially distributed and structurally connected. This merging approach allows stiffness adjustment through the collective behavior of the distributed beams while reducing overall complexity compared to having separate, independent beam assemblies. The unified structure simplifies manufacturing and assembly while maintaining the tunability benefit.
Data Source
Figure 1
Figure 2
AI summary
A centering spring assembly of a turbomachine according to an exemplary aspect of the present disclosure includes, among other things, a damper beam, a bearing support, and a spanner nut. At least a portion of the damper beam axially overlaps at least a portion of the spanner nut relative to a rotational axis of the turbomachine.