Bearing Arrangement with Resilient Elements for Load Sharing
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Solution Overview
Problem
In gas turbine engines, stacked rolling element bearings face challenges due to geometrical variations and material expansion, leading to uneven load distribution and potential failure, requiring precise matching and over-capacity design to compensate for uncertainty in load sharing.
Innovation Solution
A bearing arrangement using first and second thrust bearings with resilient elements that elastically deform to share axial thrust loads, allowing for geometrical variations and differential expansions, and a method to determine in-service loads by calibrating axial displacements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If two or more bearings are arranged adjacent one another to share thrust load, then the thrust capability is improved, but geometrical variations cause uneven load distribution leading to bearing failure
Solution Approach 1:
A resilient element is introduced as an intermediary between the thrust bearing and the bearing support structure. This resilient element absorbs geometrical variations and differential expansions, ensuring uniform load distribution across multiple thrust bearings while maintaining their collective thrust capability.
Solution Approach 2:
The resilient element changes its physical parameters (elastic deformation) in response to applied loads and temperature variations. By allowing the resilient element to deform elastically, the system adapts to geometrical variations and thermal expansions, maintaining reliable load sharing between bearings.
2Reliability
If bearing geometry is carefully controlled and matched, then load sharing is improved, but manufacturing costs increase
Solution Approach 1:
The resilient element serves as a compensating intermediary that eliminates the need for precise geometric matching between bearings. Standard off-the-shelf bearings can be used without custom matching, significantly reducing manufacturing and supply chain costs while maintaining reliable load sharing.
Solution Approach 2:
Instead of controlling bearing geometry parameters to achieve load sharing, the invention changes the system by introducing a resilient element whose deformation characteristics compensate for geometrical variations, allowing use of standard bearings with relaxed tolerances.
3Reliability
If bearing over-capacity is designed to compensate for uncertainty, then reliability is improved, but device complexity and size increase
Solution Approach 1:
The resilient element acts as a sensing intermediary that provides information about actual bearing loads through its deformation. This eliminates the need for excessive over-capacity design, as the system can be optimized based on real load conditions rather than worst-case assumptions.
4Reliability
If resilient elements are used to support outer races, then load sharing is improved, but axial displacement of outer races occurs
Solution Approach 1:
The resilient element's elastic deformation is the mechanism by which load sharing is achieved. The axial displacement is not a defect but the functional response that enables the resilient element to equalize loads between bearings. The displacement remains within acceptable limits while providing the necessary load distribution.
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 solution enables equal load sharing between bearings, reduces the need for precise matching, and allows for accurate determination of operating loads, improving reliability and maintenance scheduling.
Implementation Method 1
applying a shaft thrust load elastically deforms the resilient elements so as to axially displace the respective outer races
Data Source
AI summary
A method of determining the axial load on load-sharing thrust bearings including: providing first and second thrust bearings, each including an inner race and an outer race supported by at least one resilient element; applying a test axial load to each of the first and second thrust bearings to elastically deform the at least one resilient element so as to axially displace the outer race; determining the test axial displacement of each outer race to obtain calibration data comprising values of axial load versus axial displacement; applying an in-service axial load to the first and second thrust bearings to elastically deform the resilient elements so as to axially displace the respective outer races; measuring the in-service axial displacement of each outer race; and based on the measured in-service axial displacements, inferring from the calibration data the values of the in-service axial loads on the first and second thrust bearings.