Nested Dynamic Force Generator for Aircraft Vibration Control
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Solution Overview
Problem
Dynamic force generators with unbalanced masses used in aircraft to counteract vibrations are heavy, bulky, and have limited service life, necessitating a reduction in weight and overall dimensions while improving performance.
Innovation Solution
A dynamic force generator design featuring two unbalanced masses with a supporting shaft, rotors, and antifriction components, including plain bearings or needle rollers, integrated with electric motors and magnetic interactions to reduce friction and weight, and a housing with electromagnets for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If dynamic force generators use traditional bearing arrangements and solid structural designs, then they provide sufficient mechanical strength and stability, but they result in increased weight and larger overall dimensions
Solution Approach 1:
The patent implements nested concentric rotors where the second rotor is positioned inside the first rotor, and the third rotor inside the second rotor. This nested configuration allows multiple functional components to occupy the same spatial envelope, significantly reducing the overall external dimensions and weight of the generator while maintaining the structural integrity and mechanical strength through the distributed arrangement of bearings and support elements throughout the nested structure
Solution Approach 2:
The patent transitions from a traditional single-rotor design to a multi-rotor concentric arrangement, adding a radial dimension to the structural organization. By stacking rotors concentrically along the axial direction and distributing bearings both radially and axially, the design achieves compactness in one dimension while maintaining strength through spatial distribution of load-bearing elements
2Reliability
If dynamic force generators use conventional bearing configurations, then they provide adequate support, but they result in limited service life due to friction and wear
Solution Approach 1:
The patent divides the bearing support system into multiple segmented bearings distributed at different axial positions and radial locations. Instead of relying on a single bearing configuration, the design incorporates first bearings between the first rotor and stationary housing, second bearings between the second rotor and first rotor, and third bearings between the third rotor and second rotor. This segmentation distributes the mechanical load across multiple contact points, reducing wear on individual bearings and extending overall service life
Solution Approach 2:
The patent applies different bearing types and configurations at different locations within the generator based on local load requirements and operational conditions. Each bearing position is optimized for its specific function, with bearing characteristics tailored to the local mechanical stresses and rotational speeds, thereby maximizing reliability without requiring a uniformly complex design throughout the entire system
3Volume of moving object
If dynamic force generators use larger dimensions to accommodate all components, then they provide sufficient space for bearings and unbalanced masses, but they increase the overall footprint and weight
Solution Approach 1:
The patent utilizes nested concentric rotors where each rotor is positioned within the previous rotor, creating a compact multi-layered structure. This nesting allows sufficient operational space for multiple unbalanced masses and bearing arrangements without increasing the external footprint, as each rotor operates in its own radial zone while sharing the common axial space
Solution Approach 2:
The patent employs adjustable and variable unbalanced masses that can be repositioned or reconfigured within the nested rotor structure. This dynamic capability allows the generator to optimize its operational characteristics for different vibration counteraction requirements without requiring additional physical space, as the same structural volume accommodates variable mass distributions through controlled repositioning
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 design achieves reduced weight, compact dimensions, and extended service life by optimizing the placement of unbalanced masses and antifriction components, effectively counteracting vibrations in aircraft while minimizing power consumption and stress on bearings.
Implementation Method 1
an antifriction component provided between the first rotor and the second rotor
Implementation Method 2
an electromagnet able to interact with the first set of permanent magnets or, as appropriate, with said ribbed inner face made of ferromagnetic material of the external bore of this first rotor, in order to constitute an electric motor for the first rotor
Implementation Method 3
the unbalanced masses are set in rotation to generate a centrifugal force, the resultant of which makes it possible, in practice, to counteract a vibration generated in a structure
Data Source
AI summary
Provided is a dynamic force generator having a supporting shaft, a first rotor including an internal bore housing the supporting shaft and bearings arranged between the supporting shaft and the internal bore so that the first rotor is mounted rotatably in relation to the supporting shaft, an external bore having an inner face provided with a first set of permanent magnets. A first unbalanced mass is within the internal bore of the first rotor and mounted opposite an outer face of the external bore of the first rotor. A second rotor is mounted rotatably in relation to the first rotor, via an antifriction component provided between the first rotor and the second rotor, and includes an internal bore housing the internal bore of the first rotor so that the internal bores of the first and second rotors are concentric, and an external bore with a second set of permanent magnets.