Gearbox Flexible Region Active Vibration Control
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Solution Overview
Problem
Existing active vibration control systems for rotary wing aircraft are inadequate in generating large, controllable vibratory forces with low weight and small size, particularly when the gearbox is secured directly to the airframe without mounting struts, and are not effective against multiple frequencies of ambient vibration.
Innovation Solution
An active vibration control system for a gearbox with a flexible region allowing flexure between stages, incorporating active vibration control actuators mounted to the gearbox to counteract vibrations, which includes a transmission case and a support element to drive rotation, and can be configured to generate loads in various planes to effectively counteract multiple vibrational frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If counter-rotating eccentric masses are used to generate vibratory forces, then vibration control effectiveness is improved, but system weight increases significantly
Solution Approach 1:
The patent combines multiple eccentric masses into a single integrated housing rather than using separate housings for each mass pair. This merging of components reduces the overall weight of the actuator system while maintaining the ability to generate the required vibratory forces for vibration control.
Solution Approach 2:
The actuator is designed with a single housing that accommodates multiple eccentric masses and can control multiple frequencies of ambient vibration. This multi-functional design eliminates the need for separate actuators for different frequencies, thereby reducing total system weight.
2Manufacturing precision
If multiple eccentric masses are enclosed in separate housings to minimize unwanted moments, then vibration control precision is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple housing structures into a single integrated housing that contains all eccentric masses. This single housing design reduces device complexity by eliminating the need for multiple separate housings while still providing the necessary geometric alignment to minimize unwanted moments through precise internal positioning of the masses.
3Measurement precision
If counter-rotating eccentric mass actuators are used, then single frequency vibration control is achieved, but adaptability to multiple frequencies is limited
Solution Approach 1:
The actuator is designed with multiple eccentric masses that can operate at different rotational speeds, enabling the system to control multiple frequencies of ambient vibration. This multi-functional capability allows a single actuator to replace what would traditionally require multiple separate actuators, thereby improving adaptability while maintaining frequency control accuracy.
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 system effectively reduces airframe vibrations by generating controllable vibratory forces with reduced weight and size, capable of addressing multiple vibrational frequencies, thereby improving vibration control efficiency.
Implementation Method 1
The gearbox includes a flexible region which allows flexure between a first stage and a second stage
Implementation Method 2
at least one active vibration control actuator is arranged in vibrational communication with the flexible region to counteract vibrations transmitted between the power source and the rotatable component
Data Source
AI summary
An active vibration control system for an aircraft includes a gearbox operably coupling a power source and a component rotatable about an axis. The gearbox includes a flexible region which allows flexure between a first stage and a second stage. At least one active vibration control actuator is arranged in vibrational communication with the flexible region to counteract vibrations transmitted between the power source and the rotatable component.