Roller Bearing Oil Film Damper With Switchable Cavity Length
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Solution Overview
Problem
Existing roller bearings with oil film compression dampers in turbine engines provide limited vibration damping across a narrow range of engine speeds, failing to effectively manage vibrations across various operating conditions.
Innovation Solution
A roller bearing with a hydraulically controlled movable segment that alters the geometry of the damping oil cavity, allowing two distinct damping values by adjusting the segment's position between open and closed configurations, enhancing damping across different engine speed ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oil film compression damper uses a fixed cavity geometry, then the damping performance is stable and reliable, but the damping effectiveness is limited to a narrow range of engine speeds
Solution Approach 1:
The cavity geometry is made dynamically adjustable through a movable partition wall that can shift between positions to change the cavity volume. This allows the damping system to adapt to different engine speed ranges while maintaining reliable damping performance in each range, resolving the contradiction between stability and versatility.
Solution Approach 2:
The physical parameter of cavity volume is changed by moving the partition wall between different positions. This parameter modification enables the damper to provide effective damping across a wide range of engine speeds while maintaining stable and reliable performance within each operational range.
2Reliability
If the cavity length is increased to improve damping at low speeds, then low-speed damping performance improves, but the overall damping range remains limited and high-speed performance deteriorates
Solution Approach 1:
The partition wall is designed to move dynamically between positions, allowing the cavity length to be adjusted based on operating conditions. This enables the system to optimize low-speed damping when needed while maintaining capability for high-speed operation, thus improving both low-speed performance and overall adaptability.
Solution Approach 2:
The cavity is segmented by a movable partition wall that divides the damping space into adjustable sections. This segmentation allows independent optimization of damping characteristics for different speed ranges while maintaining the ability to switch between configurations.
3Ease of manufacture
If a single fixed damping configuration is used, then the device structure remains simple and manufacturing is easier, but the damping system cannot effectively handle multiple operating conditions
Solution Approach 1:
The partition wall is designed with a simple sliding mechanism that allows movement between fixed positions without complex control systems. This dynamic adjustment capability adds multi-condition damping capability while maintaining relative structural simplicity and ease of manufacture.
Solution Approach 2:
The partition wall movement is driven by pressure differential forces that automatically adjust the cavity configuration based on operating conditions without requiring external control systems. This self-adjusting mechanism maintains structural simplicity while providing adaptability to multiple operating conditions.
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 effective vibration damping across two distinct engine speed ranges by modifying the cavity geometry, ensuring optimal damping performance regardless of operating conditions.
Implementation Method 1
The inner cavity 17 is pressurised with oil, so that in the case of imbalance of the rotary element 14, the inner sleeve 12 moves off-centre from the axis AX in the direction of the imbalance under the effect of the centrifugal forces that this imbalance generates
Implementation Method 2
The hydraulic pressurisation of the cavity 17 thus makes it possible to dampen the off-centring to limit the vibrations generated by the presence of the imbalance
Implementation Method 3
the cavity includes a first portion and a second portion separated from one another by a radially movable segment able to occupy a closed position wherein it forms a controlled sealing barrier between the two portions
Data Source
AI summary
A bearing for a turbine engine includes an oil film compression damper, including an inner sleeve intended to receive an outer ring of a roller bearing, an outer sleeve surrounding the inner sleeve and delimiting with this inner sleeve, an axisymmetric cavity supplied hydraulically in order to form a film of damping oil, this cavity being closed at its ends by two segments. The cavity includes a first portion and a second portion separated from one another by a movable segment able to occupy a closed position in which it forms a controlled sealing barrier between the two portions, and an open position in which the two portions communicate with one another, and in that it is the first portion that is supplied hydraulically to form the film of oil.