Planetary Ring Gear Mounting With Squeeze Film Vibration Damping
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Solution Overview
Problem
Planetary gear systems in gas turbine engines experience vibrations due to radial, longitudinal, and torsional loads on the ring gear, which are transferred to the frame structure, causing deflection and potential damage.
Innovation Solution
A flexible damped mounting system is implemented, where the ring gear is connected to a damper housing with squeeze film damping members and a flexible damping wall, providing radial stiffness and damping in multiple directions to mitigate these loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the ring gear is rigidly mounted to the frame structure, then the structural support is strong, but vibrations and loads are transferred to the frame structure causing deflection and potential damage
Solution Approach 1:
A flexible mounting structure with damping elements is introduced as an intermediary between the ring gear and the frame structure. This mounting includes damping members that provide both structural support and vibration isolation, preventing the direct transfer of harmful loads to the frame while maintaining the necessary structural integrity.
Solution Approach 2:
The mounting structure incorporates flexible elements including a flexible wall and damping members that can deform elastically to absorb vibrations. These flexible components provide radial stiffness to support the ring gear while simultaneously damping radial, longitudinal, and torsional vibrations, preventing their transmission to the frame structure.
2Device complexity
If the ring gear is rigidly mounted, then the mounting structure is simple, but it causes deflection under radial, longitudinal, and torsional loads
Solution Approach 1:
The mounting structure incorporates a flexible wall that provides radial stiffness to support the ring gear while allowing controlled elastic deformation to absorb vibrations. This flexible mounting structure, though more complex than a rigid mount, prevents excessive deflection under radial, longitudinal, and torsional loads by distributing and damping the applied forces.
3Object-affected harmful factors
If damping elements are added to reduce vibrations, then vibration damping is improved, but the mounting structure becomes more complex
Solution Approach 1:
The mounting structure merges multiple functions into a single integrated assembly: structural support, vibration damping, and radial stiffness provision are all achieved through the combined flexible wall and damping members. This integrated approach provides effective vibration reduction while minimizing the overall structural complexity compared to separate mounting and damping systems.
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 reduces vibrations and potential damage by damping radial, longitudinal, and torsional loads, enhancing the structural integrity and operational stability of the planetary gear system.
Implementation Method 1
The squeeze film dampers between the ring gear and the damper housing provide radial stiffness and damping, while also providing longitudinal and torsional damping
Implementation Method 2
a flexible damping wall, the flexible damping wall providing a radial stiffness to the geared wall
Data Source
AI summary
A planetary gear system includes a sun gear, a plurality of planet gears connected to a carrier and engaging with the sun gear, and a ring gear assembly including a damper housing, and a ring gear connected to the damper housing and engaging with the plurality of planet gears. The ring gear includes a geared wall having a plurality of gear teeth engaging with the plurality of planet gears, and a damper housing attachment member radially spaced outward of the geared wall and attaching the ring gear to the damper housing. A first end of the geared wall and the damper housing engage each other via a plurality of squeeze film damping members, and a second end of the geared wall is connected to the damper housing attachment member via a flexible damping wall that is configured to provide a radial damping of the second end of the geared wall.