Bearing Inner Ring Flow Passages for Separator Land Lubrication
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Solution Overview
Problem
High-speed thrust bearings in gas turbine engines face challenges in effectively distributing lubricant to all critical areas due to space constraints, leading to inadequate lubrication and potential temperature issues.
Innovation Solution
An inner ring design with annular grooves and strategically positioned flow passages that distribute lubricant to the raceway and separator lands, ensuring sufficient lubricant depth and coverage through controlled passage sizes and orientations, even at high rotational speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional oil feed configuration with scallops and drain holes is used, then lubricant distribution to separator lands is improved, but radial space consumption increases excessively
Solution Approach 1:
The inner ring is segmented into multiple functional zones with dedicated flow passages: first flow passages supply the raceway, second flow passages supply the forward separator land, and third flow passages supply the aft separator land. This segmentation allows each region to receive targeted lubrication through optimized passage configurations, achieving reliable lubrication without requiring excessive radial space.
Solution Approach 2:
The invention transitions from traditional radial oil feed through scallops to a multi-dimensional flow passage system embedded within the inner ring structure. Flow passages extend in multiple directions (radially, axially, and circumferentially) to deliver lubricant to different bearing regions, effectively utilizing the three-dimensional space within the inner ring rather than increasing radial dimensions.
2Reliability
If flow passages are made larger to ensure lubricant coverage, then lubricant distribution improves, but lubricant retention in annular groove decreases
Solution Approach 1:
The invention optimizes the parameters of flow passages by making their diameter or width larger than the maximum fill depth of the annular groove. This parameter relationship ensures that passages are not completely filled during operation, allowing lubricant depth to be controlled by centrifugal forces while still providing adequate coverage to all bearing regions through the extended passage network.
Solution Approach 2:
The lubricant depth in the annular groove is made dynamic rather than static, allowing it to adjust with rotational speed. At any rotational speed, centrifugal forces maintain a sufficient depth of lubricant that ensures thorough coverage of all flow passages, with the depth automatically adapting to operating conditions.
3Reliability
If multiple flow passages are added to reach all bearing regions, then lubrication coverage improves, but device complexity increases
Solution Approach 1:
The annular groove serves multiple functions: it acts as a lubricant reservoir, a distribution manifold, and a depth control mechanism. By making the flow passages larger than the groove fill depth, the same groove structure controls lubricant depth for all passages simultaneously, reducing overall device complexity while maintaining comprehensive coverage.
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 inner ring design maintains a suitable lubricant depth and distribution across the bearing, ensuring proper lubrication and operating temperatures, even at high speeds, by optimizing flow passage geometry and supply channels.
Implementation Method 1
The inner surface includes an annular groove for containing a lubricant under centrifugal forces
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An inner ring (102) for a bearing comprises a ring body (108) including outer and inner surfaces (112, 110) each extending in a circumferential direction (160) about a longitudinal axis (162). The outer surface is disposed radially outside the inner surface and includes (a) a raceway (116) for supporting circumferentially arranged rolling elements, (b) a forward separator land (118), and (c) an aft separator land (120), where the raceway is axially situated between the forward and aft separator lands. The inner surface includes an annular groove (114) for containing a lubricant under centrifugal forces. Flow passages (122) for distributing the lubricant extend through the ring body from the inner surface to the outer surface, including a set of first flow passages (124) extending from the annular groove to the raceway, a set of second flow passages (126) extending from the annular groove to the forward separator land, and a set of third flow passages (128) extending from the annular groove to the aft separator land.