Propeller Blade Pitch Adjustment via Linear Actuation
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 pitch adjustment mechanism is divided into multiple independent components: a linear actuator for force generation, a sector gear for angular conversion, a pitch horn for motion transmission, and a propeller blade for thrust generation. This segmentation allows each component to be optimized for its specific function while achieving the overall goal of greater than 90 degrees pitch range through coordinated operation of discrete elements
Solution Approach 2:
The mechanism converts linear motion from the actuator into rotational motion of the propeller blade through a sector gear and pitch horn arrangement. By introducing this dimensional transformation from linear to angular movement, the system achieves a pitch range exceeding 90 degrees while maintaining a relatively simple overall structure
2Adaptability or versatility
If pitch variation is limited to less than 90 degrees, then the mechanism is easier to control, but thrust profile variability is restricted
Solution Approach 1:
The mechanism enables dynamic pitch adjustment through linear actuation, allowing the propeller blade pitch to vary continuously over a range exceeding 90 degrees. This dynamic capability provides thrust profile variability for different flight conditions while maintaining control through a single actuator that can be programmed with desired pitch schedules
Solution Approach 2:
The system changes the pitch parameter of the propeller blade over a range exceeding 90 degrees through linear actuator movement. This parameter variation enables different thrust profiles for various operational modes (climb, cruise, descent) while control simplicity is maintained through electronic actuation with programmable pitch schedules
3Adaptability or versatility
If pitch adjustment range is increased to more than 90 degrees, then maneuverability is enhanced, but mechanism complexity increases
Solution Approach 1:
The patent replaces complex mechanical pitch adjustment systems with a linear actuator-driven mechanism. The actuator directly drives the pitch horn through a sector gear, eliminating the need for complex cable systems, linkages, or multiple mechanical stages. This substitution achieves greater than 90 degrees pitch range while keeping the mechanism relatively simple through direct linear-to-angular conversion
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.