Planetary Gearbox Yoke Design for Compact Torque Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rotary-wing aircraft gearboxes are large and heavy due to the need for significant torque transfer, which is inefficient in terms of size and weight, especially in aircraft with two counter-rotating rotors.
Innovation Solution
A gearbox assembly featuring a yoke connected to an input shaft, with a planetary gear meshed to a stationary gear, and intermediate gears coaxial with the planetary gear, allowing for efficient rotational energy transmission and reduction, enabling a compact and lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional gear reduction systems with intermediate gears are used, then torque transfer capability is improved, but gearbox size and weight increase
Solution Approach 1:
The patent implements a nested planetary gear configuration where planetary gears are positioned within the yoke structure, and intermediate gears are coaxially arranged with the planetary gears. This nesting allows multiple gear functions to occupy overlapping spatial volumes, significantly reducing the overall gearbox envelope while maintaining the required torque multiplication through staged gear reductions.
Solution Approach 2:
The patent combines multiple gear reduction functions into a single integrated planetary gear stage. The planetary gears mesh with the stationary sun gear while simultaneously engaging with the annular gear, creating a compound reduction mechanism that achieves high torque multiplication in one compact unit rather than requiring separate sequential gear stages.
2Force
If traditional gear reduction systems with intermediate gears are used, then torque transfer capability is improved, but gearbox volume increases
Solution Approach 1:
The patent implements a nested planetary gear configuration where planetary gears are positioned within the yoke structure, and intermediate gears are coaxially arranged with the planetary gears. This nesting allows multiple gear functions to occupy overlapping spatial volumes, significantly reducing the overall gearbox envelope while maintaining the required torque multiplication through staged gear reductions.
Solution Approach 2:
The patent utilizes the radial dimension by arranging planetary gears in a circular pattern around the central sun gear. This radial distribution of multiple planetary gears allows the system to handle high torque loads through distributed load paths while maintaining a compact axial footprint, effectively trading radial space for reduced overall volume.
3Volume of stationary object
If planetary gear configuration is used, then gearbox size is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent divides the planetary gear system into modular components: a yoke assembly containing the planetary gears, a stationary sun gear, coaxial intermediate gears, and an annular gear. This segmentation allows each component to be manufactured and tested independently before final assembly, reducing the complexity of manufacturing the complete planetary gear system while achieving compact dimensions.
4Adaptability or versatility
If coaxial intermediate gears are added, then adaptability to different reduction ratios is improved, but device complexity increases
Solution Approach 1:
The patent designs the coaxial intermediate gears to serve multiple functions: they act as idler gears to reverse rotation direction, provide additional reduction stages, and enable different gear ratio configurations by engaging with either the planetary gears or the annular gear. This multi-functionality increases adaptability to various reduction requirements without proportionally increasing overall system complexity.
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 solution reduces the size and weight of the gearbox while maintaining efficient torque transfer, allowing for adaptation to different gear reduction requirements and the ability to drive multiple output shafts, thereby optimizing space and weight in rotary-wing aircraft.
Implementation Method 1
A planetary gear is rotatably positioned in the yoke and is meshable with the stationary gear such that rotation of the yoke about the stationary gear drives rotation of the planetary gear about a pin axis, via the mesh of the planetary gear to the stationary gear
Implementation Method 2
An intermediate gear is located substantially coaxially with the planetary gear and is operably connected to the planetary gear such that rotation of the planetary gear about the pin axis drives rotation of the intermediate gear about the pin axis
Data Source
AI summary
A gearbox assembly includes a yoke operably connectable to an input shaft and rotatable about a stationary gear located at a central axis. A planetary gear is rotatably located in the yoke and is meshable with the stationary gear such that rotation of the yoke about the stationary gear drives rotation of the planetary gear, via the mesh between the planetary gear and the stationary gear, about a pin axis. An intermediate gear is located substantially coaxially with the planetary gear and is operably connected to the planetary gear such that rotation of the planetary gear about the pin axis drives rotation of the intermediate gear about the pin axis. At least one output gear is located at the central axis and is operably meshed to the intermediate gear.