Variable-Pitch Propeller Hub Layout for Reduced Axial Length
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing propellant force generators are large in the axial direction due to the alignment of a threaded portion with an electric motor, necessitating a larger overall device size.
Innovation Solution
A propellant force generator design that includes a first motor with a hollow section, a second motor located within the first motor, and converting units positioned to reduce axial protrusion, allowing for a compact design by arranging motors in parallel and locating parts of the converting units within the hub.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the threaded portion is aligned linearly with the electric motor, then the pitch angle can be adjusted, but the axial size of the device increases
Solution Approach 1:
The patent places the second motor and first converting unit inside the hollow rotational shaft of the first motor. This nested arrangement allows the pitch adjustment mechanism to be contained within the propeller drive motor, eliminating the need for external linear alignment and reducing the overall axial size while maintaining pitch adjustment functionality.
Solution Approach 2:
The patent transitions from a linear axial arrangement to a radial/rotational arrangement by using a rotational motor (second motor) connected through a converting unit to generate axial motion. This dimensional change allows pitch adjustment without requiring linear alignment along the axial direction, thereby reducing axial size.
2Ease of manufacture
If the first converting unit is located outside the first motor, then the mechanism is simpler to implement, but the device size in axial direction increases
Solution Approach 1:
The first converting unit is positioned inside the hollow rotational shaft of the first motor, creating a nested configuration. This allows the converting mechanism to be integrated within the existing motor structure without requiring additional external space in the axial direction, thus reducing overall device size while maintaining manufacturability.
Solution Approach 2:
The hollow rotational shaft of the first motor serves dual purposes: as the structural component of the propeller drive motor and as the housing for the first converting unit. This multi-functional use of space eliminates the need for separate external housing, simplifying the overall structure and reducing axial size.
3Device complexity
If a threaded portion is used for pitch adjustment, then the mechanism is straightforward, but the axial protrusion increases
Solution Approach 1:
The patent replaces the traditional threaded portion mechanism with a rotational motor-driven converting unit system. The second motor generates rotational motion that is converted to axial motion through the first converting unit, providing pitch adjustment without the axial protrusion associated with threaded portions while maintaining mechanism simplicity through standardized motor and converter components.
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 design reduces the size of the propellant force generator in the axial direction while enabling variable pitch angles for rotational blades, improving stability and response speed without increasing blade length or weight, and eliminating the need for hydraulic systems.
Implementation Method 1
the rotation-linear motion converting unit includes a ball screw including a ball screw shaft and a ball screw nut
Implementation Method 2
the linear motion-rotation converting unit includes N racks and N pinions corresponding to the N rotational blades
Data Source
Figure 1(a)~1(c)
Figure 2
Figure 3
AI summary
The size of a propellant force generator in the axial direction of a rotational shaft of a motor is reduced while making the pitch angles of rotational blades driven by the motor variable. The propellant force generator (1) includes a propellant-force generating motor (2) adapted to generate a propellant force for rotational blades (H1 to H3), a pitch varying motor (5) adapted to generate a rotational motion for changing pitch angles of the rotational blades (H1 to H3), a rotation-linear motion converting unit (7) adapted to convert the rotational motion generated by the pitch varying motor (5) into a linear motion, and a linear motion-rotation converting unit (8) adapted to convert the linear motions converted by the rotation-linear motion converting unit (7) into rotational motions. At least a part of the linear motion-rotation converting unit (7) is located within the propellant-force generating motor (2).