Gas Turbine Bearing Centering Spring With Axial Beam Structure
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Solution Overview
Problem
Current bearing systems in gas turbine engines face challenges in achieving a smaller, lighter, and more manufacturable centering spring arrangement, particularly in intershaft bearing compartments, which affects engine weight, cost, and performance.
Innovation Solution
A bearing assembly with an annular centering spring structure having a base portion, tip portion, and axially extending beams, optionally with stops and varying beam thickness, supports the bearing outer race, allowing independent rotation of shafts and optimizing stiffness and space efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If traditional centering spring arrangements are used in intershaft bearing compartments, then the bearing outer race is supported, but the structure is larger, heavier, and less manufacturable
Solution Approach 1:
The centering spring is segmented into multiple axially extending beams that are distributed circumferentially around the bearing outer race. Each beam acts as an independent elastic element, allowing the spring to be manufactured as separate components that can be assembled together, improving manufacturability and reducing weight compared to a traditional monolithic spring structure
Solution Approach 2:
The centering spring transitions from a conventional coiled spring geometry to an annular structure with axially extending beams. This dimensional change allows the spring to achieve the required centering function through beam deflection in the radial direction while eliminating the need for complex coiled spring manufacturing processes, thereby improving manufacturability and reducing weight
2Productivity
If the centering spring uses uniform beam thickness, then manufacturing is simpler, but the stiffness and performance optimization is limited
Solution Approach 1:
The centering spring employs beams with non-uniform thickness, where the beam thickness varies along the axial length. This local quality variation allows specific regions of the spring to have different stiffness characteristics, optimizing the centering force distribution and bearing support performance while maintaining manufacturability through standard machining processes
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 results in a more manufacturable, cost-effective, and weight-efficient centering spring design that effectively supports bearing deflections without axial stress, enhancing the overall structure's performance and efficiency.
Implementation Method 1
The centering spring is an annular structure including a base portion, a tip portion, and a plurality of beams extending axially between the base portion and the tip portion
Data Source
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AI summary
A bearing assembly 100 of a gas turbine engine 20 includes a bearing inner race 106, a bearing outer race 102 located radially outboard of the bearing inner race 106 and a plurality of bearing elements 108 located between the bearing inner race 106 and the bearing outer race 102. A centering spring 110 is operably connected to and supports the bearing outer race 102. The centering spring 110 is an annular structure including a base portion 116, a tip portion 120, and a plurality of beams 130 extending axially between the base portion 116 and the tip portion 120.