Magnetic Brake Locking Mechanism for Rotorcraft Blades
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Solution Overview
Problem
Existing rotorcraft blade locking systems fail to prevent accidental activation during rotor rotation, particularly in flight, due to the lack of effective mechanisms to lock the blades' degrees of freedom and prevent parasitic rotation caused by vibrations.
Innovation Solution
A device with a rotary electric actuator and drive mechanism featuring magnetic brake means and an irreversible speed reducer, including a wormscrew, to securely lock the blade-holding structure relative to the hub, preventing rotation during rotor vibrations and power outages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking device is provided for the hinged holding structure, then the blade-holding structure can be locked relative to the hub about drag and pitch hinge axes, but the system may be accidentally activated while the rotor is revolving
Solution Approach 1:
The brake means are designed to apply preliminary anti-action by creating magnetic friction that prevents the actuator from rotating unless the electromagnetic force actively overcomes it. This preliminary restraint prevents accidental activation while allowing controlled operation when electricity is supplied to the motor.
2Reliability
If brake means are added to prevent accidental rotation, then protection against parasitic rotation is improved, but device complexity increases
Solution Approach 1:
The patent replaces traditional mechanical brake systems with magnetic brake means that utilize electromagnetic fields and magnetic attraction/repulsion forces. This substitution eliminates complex mechanical linkages, springs, and friction surfaces while achieving reliable braking through electromagnetic interaction between the motor and actuator components.
3Stability of the object's composition
If an irreversible drive mechanism is used, then locking stability is improved, but the ability to unlock requires active motor operation
Solution Approach 1:
The irreversible nature of the drive mechanism, which initially appears to complicate unlocking operations, is converted into a benefit by the magnetic brake means. The brake prevents parasitic rotation that would otherwise interfere with unlocking, and the combination ensures that unlocking occurs only through controlled motor operation, transforming the irreversible characteristic from a potential problem into a reliability feature.
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
Ensures the blades remain securely locked and prevents accidental activation, maintaining stability and safety during flight and folding operations, while being lightweight and compact.
Implementation Method 1
brake means for the rotary electric actuator and/or the drive mechanism to prevent rotation of said actuator and of the drive mechanism, in particular under the effect of rotor vibration and in the absence of electricity being fed to the motor
Implementation Method 2
the drive mechanism is irreversible. In particular, the mechanism may include a speed reducer comprising a wormscrew for driving a gearwheel
Data Source
AI summary
A device for locking a holding structure for securing a foldable blade of a rotorcraft rotor to the hub of the rotor. The holding structure is hinged in pitch and in drag relative to the hub and the rotor includes, for the purpose of folding the blade, elements for locking the blade-holding structure in pitch and in drag, which device is remarkable in that the associated drive elements includes brake elements preventing it from turning in flight, in particular under the effect of vibration from the rotor.