Two-Sided Spring Finger Ring for Bearing Damping and Low Weight
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Solution Overview
Problem
Traditional support assemblies for gas turbine engine bearings face challenges in reducing weight and size while providing adequate damping, especially under dynamic forces and no-oil conditions, where radial spring fingers may not offer sufficient stiffness variation and add undesirable weight.
Innovation Solution
A support assembly featuring a spring finger ring with two-sided spring fingers and a shape memory alloy, providing adaptive stiffness and damping through variable geometry, integrated with a squeeze film damper or squirrel casing, to enhance bearing performance and reduce weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional radial spring fingers are used to dampen bearing loads, then damping capability is provided, but weight and size increase and stiffness variation is limited
Solution Approach 1:
The spring fingers are designed with flexible geometry that allows them to dynamically adjust their stiffness characteristics based on operating conditions. The fingers can bend and deform elastically to provide variable damping, transitioning from a static structure to a dynamic system that adapts to varying load conditions, thereby reducing the need for oversized components while maintaining reliability.
Solution Approach 2:
The invention changes the physical parameters of the spring fingers by introducing variable cross-sectional geometry and flexible configurations. This allows the stiffness parameter to vary dynamically rather than remaining fixed, enabling the system to provide adequate damping capability while using lighter, more optimized finger dimensions that reduce overall weight.
2Reliability
If larger radial spring fingers are used to provide adequate damping, then damping capability is improved, but device size increases and engine efficiency is reduced
Solution Approach 1:
By designing spring fingers with flexible, bendable geometry, the system achieves dynamic adaptation where the fingers can undergo larger deformations within a compact volume. This dynamic behavior allows smaller fingers to provide the same damping effect as larger rigid fingers, reducing the volume occupied by the damping mechanism while maintaining reliability.
Solution Approach 2:
The spring fingers are designed as flexible structural elements that can bend and deform elastically, similar to flexible shells. This flexibility allows them to provide substantial damping capability within a reduced volume, as the thin, flexible fingers can undergo larger deflections to absorb energy, replacing the need for bulky rigid damping structures.
3Device complexity
If traditional spring finger design is used, then structural simplicity is maintained, but stiffness variation is insufficient under dynamic forces
Solution Approach 1:
The spring fingers are designed with flexible geometry that enables them to transition from a static, simple structure to a dynamic system with variable stiffness. The fingers can bend and deform to adjust their effective stiffness in real-time based on applied loads, providing adaptability while maintaining relatively simple structural forms that do not require complex mechanisms.
Solution Approach 2:
The invention changes the physical parameters of the spring fingers by introducing variable cross-sectional geometry and flexible configurations. This allows the stiffness parameter to vary dynamically rather than remaining fixed, enabling the system to adapt to different operating conditions while maintaining structural simplicity through continuous or smoothly varying geometries rather than complex discrete components.
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 reduces the weight and size of the support assembly while offering increased stiffness variation and backup damping in no-oil conditions, preventing bearing coning and enhancing overall engine efficiency and performance.
Implementation Method 1
a plurality of spring fingers extending between the inner and outer rings such that the plurality of fingers provides damping of the outer race
Implementation Method 2
A support assembly featuring a spring finger ring with two-sided spring fingers and a shape memory alloy, providing adaptive stiffness and damping through variable geometry
Implementation Method 3
integrated with a squeeze film damper or squirrel casing
Data Source
AI summary
A support assembly for a bearing of a gas turbine engine including a spring finger ring positioned radially exterior to an outer race of the bearing. The spring finger ring includes an outer ring positioned radially exterior to the outer ring, an inner ring positioned radially interior to the outer ring, and a plurality of spring fingers extending between the inner and outer rings. One or more spring fingers configured as two-sided spring fingers including a first ligament coupled to the outer ring and extending at a first circumferential angle to a first radial bumper proximate to the inner ring and a second ligament coupled to the inner ring and extending at a different second circumferential angle to a second radial bumper proximate to the outer ring. The first and second radial bumpers define first and second radial gaps between the bumpers and the inner and outer rings, respectively.