Nested Spring Damper Bearing for Gas Turbine Rotor Vibration
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Solution Overview
Problem
Gas turbine engine bearing systems face challenges in achieving optimal rotor dynamic stiffness and minimizing vibrational forces while maintaining a compact and lightweight design, particularly due to clearance requirements, geometric tolerances, and thermal growth considerations.
Innovation Solution
A sprung and damped bearing system is designed with a cage-like spring structure and a nested damper ring configuration, utilizing a cylindrical beam arrangement and fluid damping to absorb non-synchronous vibrations, allowing for an axially compact assembly that reduces the bearing compartment length and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional bearing system with sufficient clearance and tolerance accommodation is designed, then reliability is improved, but the bearing compartment axial length increases
Solution Approach 1:
The damper ring is nested within the spring structure, with the damper ring positioned inside the cage-like spring assembly. This nesting arrangement allows both components to occupy the same axial space, significantly reducing the overall bearing compartment axial length while maintaining the functional integrity of both the spring and damper ring
Solution Approach 2:
The invention transitions from a linear axial arrangement to a three-dimensional nested configuration. By utilizing radial and circumferential dimensions within the spring structure, the damper ring is accommodated without increasing axial length, effectively moving the problem from one dimension to multiple dimensions
2Reliability
If a traditional bearing system with adequate clearance and tolerance is designed, then reliability is improved, but the weight of the engine increases
Solution Approach 1:
The nested configuration of the damper ring within the spring structure eliminates the need for additional clearance space and reduces the overall component envelope. This compact arrangement reduces material requirements and structural support needs, thereby reducing engine weight while maintaining reliability
Solution Approach 2:
The invention merges the spring and damper ring into a single integrated bearing system assembly. By combining these components into one compact unit with shared structural support and common mounting features, the total weight is reduced compared to separate, distributed components
3Ease of manufacture
If a compact bearing system design is implemented, then ease of manufacture is improved, but manufacturing precision requirements worsen
Solution Approach 1:
The bearing system is segmented into distinct modular components including the spring assembly, damper ring, and bearing. Each component can be manufactured and assembled independently, simplifying the manufacturing process. The segmentation allows for standardized production of individual parts while maintaining precise relative positioning through designed interface features
Solution Approach 2:
The nested arrangement provides natural alignment and positioning features that reduce the need for complex precision machining. The concentric nature of the nested components self-aligns during assembly, reducing geometric tolerance requirements compared to non-nested configurations
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 effectively absorbs rotor vibrations, enables a lighter and more compact gas turbine engine design, and simplifies the manufacturing process while providing design flexibility.
Implementation Method 1
The spring is typically a series of beams arranged in a cage-like structure to provide particular rotor dynamic stiffness requirements
Implementation Method 2
The damper minimizes the transfer of vibrational forces from the bearing assembly into static structure
Data Source
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AI summary
A bearing system (38A) for a gas turbine engine includes a spring (62) defined about an axis of rotation. The spring (62) has a multiple of beams (82) which extend between a flange structure (84) and an attachment structure (86). A damper (64) is defined about the axis of rotation and mounted to the spring (62) to at least partially axially overlap the multiple of beams (82).