Conical Eddy-Current Wheel Brake With Airgap Torque Control
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Solution Overview
Problem
Aircraft wheel brakes using friction materials face issues with wear, contamination, and health hazards due to ejected dust, necessitating an alternative braking mechanism that minimizes weight and size while providing effective braking control.
Innovation Solution
Eddy-current brake assemblies utilizing rotors and stators with frustoconical surfaces and sliding translation to control airgap, combined with a frictional brake for supplemental braking, offering precise torque control and additional braking capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If friction materials are used in wheel brakes, then braking force is provided, but wear occurs requiring maintenance and replacement
Solution Approach 1:
The patent replaces the mechanical friction-based braking system with an electromagnetic eddy-current braking system. The eddy-current brake uses a magnetic field interacting with a conductive rotor to generate resistive torque without physical contact, eliminating wear of friction materials while maintaining effective braking force.
2Force
If friction materials are used in wheel brakes, then braking force is provided, but dust is ejected contaminating components and creating health hazards
Solution Approach 1:
The eddy-current braking system replaces mechanical friction with electromagnetic interaction, eliminating the generation of dust and contamination. The magnetic field interacts with the conductive rotor to produce braking force without physical contact, thus no wear debris or dust is ejected.
3Ease of operation
If conventional eddy-current brake designs are used, then braking torque can be varied, but the system requires complex flux modulation mechanisms
Solution Approach 1:
The patent controls braking torque by varying the airgap distance between the stator and rotor, rather than modulating magnetic flux density. This geometric parameter change is achieved through simple axial translation of the stator, providing intuitive and straightforward braking control without complex flux modulation mechanisms.
Solution Approach 2:
The patent replaces complex electromagnetic flux modulation with simple mechanical translation of the stator along the axial direction. This mechanical adjustment of the airgap distance provides a more straightforward and less complex method for controlling braking torque.
4Weight of moving object
If lightweight and compact braking systems are used, then weight and size are reduced, but braking control precision may be compromised
Solution Approach 1:
The patent achieves precise braking control through accurate adjustment of the airgap distance parameter. By controlling the axial position of the stator, the system precisely modulates the magnetic coupling between stator and rotor, enabling fine control of braking torque while maintaining a compact and lightweight design.
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 eddy-current brake system provides compact, lightweight, and efficient braking with improved control over braking force, supplemented by frictional braking for low-speed or stationary conditions, reducing maintenance and contamination risks.
Implementation Method 1
electromagnetic effects, notably 'eddy-current' brakes, which generate a resistive torque due to the interaction of a fixed magnetic field and a rotating conductor
Implementation Method 2
The resistive torque that results from the brake depends on the speed of rotation of the conductor, the conductivity of the conductor, and the magnetic flux density
Data Source
AI summary
A brake assembly is suitable for use in conjunction with a wheel having a rim rotatably mounted to an axle. The brake assembly includes a rotor configured to rotate about the axis with the rim. The rotor has a first frustoconical rotor surface and either a conductive element or a magnet. The brake assembly further includes a stator fixed in rotation about the axis and configured for selective translation parallel to the axis. The stator has a first frustoconical stator surface proximate to the first frustoconical rotor surface and a conductive element, when the stator has a magnet, or a magnet, when the stator has a conductive element.