Bearing Cage Drain Conduits for Lower Lubricant Heat Buildup
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Solution Overview
Problem
Turbine engines experience high bearing temperatures due to increased lubricant requirements for cooling, leading to excessive heat generation and the need for larger lubricant lines and heat exchangers, which impacts heat load management.
Innovation Solution
Incorporation of lubricant drains in bearing assemblies to facilitate continuous lubricant flow in and out, reducing residence time and heat generation by draining lubricant from cavities between roller bearings, using conduits and orifices in the bearing cage and outer race to direct lubricant to a sump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If increased lubricant supply is used for cooling, then bearing temperature control is improved, but heat generation increases and larger heat exchangers are required
Solution Approach 1:
The patent extracts and removes lubricant from the bearing assembly through dedicated drain paths (conduits in the cage, grooves in the outer race) to eliminate excessive heat generation. By taking out the lubricant after it has performed its cooling function, the system avoids the energy loss associated with heating and recirculating large volumes of lubricant, thereby reducing the size requirements for heat exchangers.
Solution Approach 2:
The patent implements a system where lubricant is discarded from the bearing assembly through drain conduits and grooves after serving its cooling purpose. This selective discarding of lubricant prevents the accumulation of excessive heat in the lubricant, thereby reducing the overall heat generation in the system and allowing for smaller heat exchanger components.
2Temperature
If larger heat exchangers and lubricant lines are used, then cooling capacity is improved, but device complexity and size increase
Solution Approach 1:
The patent extracts lubricant from the bearing assembly through integrated drain paths (conduits in the cage, grooves in the outer race) to improve cooling efficiency. This extraction mechanism allows the system to achieve effective cooling without requiring oversized heat exchangers or complex lubricant delivery systems, thereby reducing overall device complexity and size.
Solution Approach 2:
The bearing assembly components (cage, outer race) perform multiple functions: they not only support the rolling elements but also serve as lubricant distribution and drainage systems through integrated conduits and grooves. This multi-functionality eliminates the need for separate, complex cooling system components, thereby reducing device complexity while maintaining effective cooling capacity.
3Temperature
If lubricant residence time in bearing assembly is increased, then cooling effectiveness is improved, but heat generation increases
Solution Approach 1:
The patent implements continuous lubricant flow through the bearing assembly via supply channels and drain paths. This continuous action ensures that lubricant is constantly refreshed in the bearing cavities, maintaining effective cooling without allowing the lubricant to remain stationary and generate excessive viscous heat. The continuous flow regime optimizes the balance between cooling effectiveness and heat generation.
Solution Approach 2:
The patent extracts lubricant from the bearing assembly through dedicated drain paths (conduits in the cage, grooves in the outer race) to reduce residence time. By continuously removing lubricant after it has absorbed heat, the system prevents excessive viscous heat generation while maintaining effective cooling through the continuous circulation of fresh lubricant.
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
Reduces bearing temperatures by 20-30%, allowing for smaller lubricant lines and heat exchangers, and enables increased shaft speeds with reduced lubricant supply, thereby optimizing heat management.
Implementation Method 1
The bearing assemblies are lubricated to facilitate rotation of the bearing elements
Implementation Method 2
A lubricant drain of the bearing assembly may include a cage having a plurality of lubricant drains that facilitate movement of the lubricant and/or removal of the lubricant from the bearing assembly
Data Source
AI summary
Lubricant draining bearing assemblies are disclosed. An example apparatus includes a first race, a second race, roller bearings positioned between the first race and the second race, and a cage positioned around the roller bearings between the first race and the second race, the cage including a first radial surface, a second radial surface, and an axial surface, the first radial surface facing the first race, the second radial surface facing the second race, the axial surface facing away from the roller bearings, the cage including at least one conduit extending between the first radial surface and at least one of the second radial surface or the axial surface, the conduit defining a flow path for a fluid out of a cavity between the first race, the roller bearings, and the cage.