Locking Finger for Electric Motor Shaft Stabilization
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Solution Overview
Problem
Vertical take-off aircrafts experience instability and energy inefficiency due to propeller windmilling, which causes unpredictable forces and increased aerodynamic drag when not driven by a motor, and existing solutions like motor torque locking reduce energy efficiency.
Innovation Solution
A locking system comprising a housing and indexing element that limits rotational movement to a predetermined sector, switching configurations based on torque thresholds, allowing passive locking and unlocking of the propeller, with assemblies movable in translation between rest and service positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If motor torque is applied to lock the propeller, then propeller rotation is prevented and aircraft stability is improved, but energy consumption increases
Solution Approach 1:
The locking system uses the propeller's own rotational kinetic energy to drive the indexing element out of the housing, achieving automatic unlocking without external power. The system serves itself by converting the harmful windmilling rotation into the mechanical energy needed for unlocking.
Solution Approach 2:
The patent converts the harmful effect of propeller windmilling (uncontrolled rotation causing instability and drag) into a beneficial mechanism for automatic unlocking. The uncontrolled rotation that causes problems is harnessed to drive the indexing element out of the housing, enabling the propeller to transition from locked to unlocked state without external energy input.
2Loss of energy
If the propeller is locked in position, then aerodynamic drag is reduced, but the ability to transition between flight phases is limited
Solution Approach 1:
The locking system transitions from a static locked state to a dynamic unlocked state based on operating conditions. The indexing element can be inserted into or removed from the housing depending on whether the propeller needs to be locked (reducing drag) or unlocked (enabling rotation for different flight phases), providing adaptability while minimizing energy loss.
3Stability of the object's composition
If the indexing element is always inserted into the housing, then rotational movement is limited and stability is maintained, but the propeller cannot be unlocked for motor-driven rotation
Solution Approach 1:
The indexing element acts as an intermediary between the propeller and the housing. When inserted, it mediates to limit rotation and provide stability. When removed, it allows free rotation for motor-driven operation. The thrust opposing member serves as an intermediary that uses thrust forces to automatically position the indexing element in or out of the housing based on operational needs.
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 stabilizes the aircraft by minimizing propeller rotation-induced forces and drag, reducing energy consumption by enabling passive locking and unlocking, thus enhancing energy efficiency.
Implementation Method 1
the return device comprises a support spring for pushing one of the indexing element and of the housing towards the other
Implementation Method 2
the indexing element comprises a rolling element able to be introduced into the housing
Data Source
AI summary
Aircraft comprising a primary propeller driven in rotation by a motor, the motor having a first assembly and a second assembly movable in rotation relative to each other along an axis of rotation, the primary propeller being secured in rotation to one of said first assembly and second assembly, the first assembly and the second assembly being movable in translation relative to each other along a direction of translation defined by the axis of rotation, between a rest position and a service position, characterized in that said aircraft comprises a locking system, comprising a housing and an indexing element, the housing being formed in one among the first assembly and the second assembly, the indexing element being secured to the other among the first assembly and the second assembly, the locking system having an engaged configuration in which the indexing element is at least partially inserted into the housing.