Folding Propeller Hub Locking Against Unintentional Blade Folding
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Solution Overview
Problem
Existing propellers for drones are prone to unintentional blade folding due to acceleration and deceleration, leading to response delays and controllability issues.
Innovation Solution
A propeller design featuring radially movable blades with engaging portions that restrict pivoting during rotation and allow folding when stationary, using centrifugal forces and engaging/disengaging mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the blade is configured to be pivotable with respect to the hub using bolts, then the blade can be folded when stationary, but the blade may unintentionally fold during rotation due to acceleration and deceleration
Solution Approach 1:
The blade attachment system transitions from a static bolted connection to a dynamic engaging portion mechanism that automatically adjusts between folded and unfolded states. The engaging portions utilize centrifugal force generated during rotation to maintain blade position, while allowing controlled folding when stationary, thus resolving the contradiction between adaptability and reliability.
Solution Approach 2:
The blade attachment mechanism changes its mechanical parameters (engaging/disengaging) based on rotational state. During rotation, centrifugal force causes the engaging portions to engage and lock the blade in position. When stationary, the engaging portions disengage, allowing blade folding. This parameter change resolves the contradiction by adapting the attachment state to operational conditions.
2Reliability
If the blade is restricted from pivoting during rotation, then unintentional folding is prevented, but the blade cannot be folded when stationary
Solution Approach 1:
The attachment mechanism is designed to be dynamic rather than static, automatically engaging during rotation to prevent folding and disengaging when stationary to allow folding. This dynamic behavior resolves the contradiction by making the restriction conditional on rotational state rather than constant.
Solution Approach 2:
The blade attachment system uses the centrifugal force generated during rotation itself to engage the engaging portions and lock the blade in position. No external actuation is needed - the rotational motion automatically activates the position-restricting function, while the absence of rotation automatically allows folding.
3Device complexity
If the blade is allowed to pivot freely during rotation, then the structure is simple, but response delay and controllability deteriorate
Solution Approach 1:
The engaging portions automatically engage and disengage based on centrifugal force during rotation, without requiring external control systems or complex actuation mechanisms. This self-regulating behavior maintains relatively simple structure while ensuring rapid blade position stabilization, thus resolving the contradiction between simplicity and response speed.
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
Prevents unintentional blade folding during rotation, maintaining controllability and reducing electric consumption by stabilizing blade position.
Implementation Method 1
the blade is moved radially outward by centrifugal forces
Data Source
AI summary
A propeller designed to prevent unintentional folding of the blades includes a hub, a blade, a first engaging portion, and a second engaging portion. The blade is attached to the hub to be radially movable with respect thereto. The blade is attached to the hub to be pivotable with respect thereto. The first engaging portion is provided in the hub. The second engaging portion is provided in the blade. The second engaging portion is configured to be engaged with the first engaging portion to restrict the blade from pivoting with respect to the hub when the blade is moved radially outward. The second engaging portion is configured to be disengaged from the first engaging portion when the blade is moved radially inward.