Three-Point Rolling Bearing Drain Layout for Lubrication Cooling
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Solution Overview
Problem
Existing rolling bearings in turbine engines experience significant power dissipation due to sliding at two contact points on the outer ring under high-speed operations, which nullifies the lubrication and cooling benefits, especially when subjected to axial and radial forces.
Innovation Solution
A three-point contact rolling bearing design with an outer ring featuring a drain in the outer raceway that is eccentrically positioned and disjoint from the third contact point, allowing fluid circulation and preventing contact between rolling elements and the drain, even under thrust reversals, while maintaining efficient lubrication and cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If drilling is performed in the radial plane to enable fluid circulation, then lubrication and cooling are improved, but the bearing requires four contact points which causes sliding and power dissipation at high speeds
Solution Approach 1:
The patent positions the drain hole asymmetrically in the outer ring, specifically in the sector between the rolling plane and the distal end, away from the third contact point. This asymmetric positioning allows the drain to function effectively for fluid circulation while avoiding interference with the rolling elements at the contact point, thereby preventing the sliding and power dissipation issues associated with symmetric four-point contact designs
2Strength
If four contact points are used to avoid rolling element contact with drilling, then structural integrity is maintained, but sliding occurs at the second contact point under axial and radial forces causing power dissipation
Solution Approach 1:
The patent applies local quality by creating a specific geometric configuration where the outer ring has distinct sectors: one sector contains the third contact point for load bearing, while another sector contains the drain hole for fluid circulation. This localized functional differentiation allows each region to optimize its specific function without compromising the other, maintaining structural integrity while eliminating the sliding issue
3Productivity
If the drain is positioned in the outer raceway, then fluid circulation is enabled, but rolling elements may contact the drain causing operational issues
Solution Approach 1:
The patent resolves the conflict by utilizing the angular/sectoral dimension of the outer ring. The drain is positioned in a specific angular sector that is spatially separated from where the rolling elements make contact. This dimensional separation in the angular domain allows both functions - fluid circulation through the drain and reliable rolling element operation - to coexist without interference
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 design ensures effective lubrication and cooling by preventing power dissipation and material degradation, allowing the use of steel rolling elements and optimizing the cooling system without the need for additional cooling systems in turbine engines.
Implementation Method 1
Rolling bearings employed in turbine engines are employed at high speeds. It is thus necessary to ensure in them a circulation of a fluid, typically oil or fuel, in order to ensure the lubrication and the cooling of the rolling bearings.
Data Source
AI summary
Rolling bearing with three contact points, wherein the inner raceway, the third contact point being located in a sector of the outer raceway delimited by a proximal end of the outer raceway on the one hand, and by the rolling plane on the other hand, characterized in that the outer ring comprises a drain provided in the outer raceway, and opening from an outer surface of the outer ring, said drain opening eccentrically on the outer raceway with respect to the rolling plane, in a sector of the outer raceway delimited by the rolling plane on the one hand, and a distal end of the outer raceway on the other hand, the drain and the third contact point being disjoint.