Compound Gearbox Propeller Pitch Control for Thrust Reversal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing propeller blade pitch adjustment mechanisms for aerial vehicles have limited range of motion, typically allowing less than a 90-degree change, which restricts the variability of thrust profiles and maneuverability.
Innovation Solution
The development of propeller blade pitch adjustment apparatuses that enable a variation of more than 90 degrees, potentially up to 360 degrees, using a compound gearbox and pitch adjustment spools, allowing for thrust reversal and efficient propulsive performance without reducing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing pitch adjustment mechanisms are used, then the mechanism structure is simple, but the range of motion is limited to less than 90 degrees
Solution Approach 1:
The mechanism is divided into two separate gearboxes: a first gearbox that maintains a constant speed relationship between the motor shaft and propeller shaft, and a second gearbox that independently adjusts the blade pitch angle. This segmentation allows the range of motion to exceed 90 degrees while keeping each individual gearbox relatively simple in structure.
2Adaptability or versatility
If a compound gearbox is used to achieve greater than 90 degrees pitch variation, then the range of motion is improved, but the device complexity increases
Solution Approach 1:
Instead of using a single complex compound gearbox, the invention segments the pitch adjustment function into a second gearbox that works in conjunction with the first gearbox. The second gearbox specifically handles the pitch angle adjustment while the first gearbox maintains constant speed transmission, thereby achieving greater than 90 degrees pitch variation without excessive complexity in any single gearbox unit.
3Adaptability or versatility
If pitch adjustment mechanisms are added to enable thrust reversal and variable pitch profiles, then the adaptability is improved, but the device complexity and potential loss of propulsive efficiency increase
Solution Approach 1:
The invention enables dynamic adjustment of the propeller blade pitch angles through the second gearbox, allowing the thrust profile to be varied in real-time. This dynamic capability provides thrust reversal and enhanced maneuverability while maintaining propulsive efficiency through precise control of blade orientation relative to the airflow.
Solution Approach 2:
The invention changes the pitch angle parameter of the propeller blades through the second gearbox mechanism. By adjusting this parameter, the system achieves thrust reversal and variable thrust profiles without significantly impacting propulsive efficiency, as the blade geometry itself remains optimal for different pitch angles.
Data Source
AI summary
Various mechanisms for adjusting pitches of propeller blades are described. For example, the pitch adjustment mechanism may include a propeller hub enclosing a geared mechanism that cooperates with a compound gearbox having first and second planetary stages to adjust pitches of propeller blades. Alternatively, the pitch adjustment mechanism may include a propeller hub enclosing a pitch adjustment assembly that utilizes tension cables and torsion springs, or rack-and-pinion structures, to adjust pitches of propeller blades. Using any of the various mechanisms, the pitches of propeller blades may be rotated at least 90 degrees, and up to and exceeding 360 degrees, in order to effect thrust reversals and/or adjust thrust profiles.