Sun Gear Differential for Integrated Drive Generator Speed Range
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Solution Overview
Problem
The two ring gear configuration in aircraft electric power generation hydro-mechanical transmissions is limited to a lower input speed range and forces specific packaging arrangements, requiring a side-to-side differential with gearing between the differential and hydraulic unit.
Innovation Solution
A sun gear configuration for an integrated drive generator with a differential ratio of approximately 0.5, allowing for a wider input speed range and enabling in-line packaging with the hydraulic unit, eliminating the need for gearing between the sun gear and hydraulic unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a two ring gear configuration is used, then the differential can be packaged side-to-side with hydraulic unit, but the input speed range is limited to lower speeds
Solution Approach 1:
The patent changes the fundamental gear configuration parameter from two ring gears to a sun gear configuration, which alters the differential ratio and enables operation across a wider input speed range while eliminating the need for additional gearing between the differential and hydraulic unit
Solution Approach 2:
The sun gear configuration serves multiple functions simultaneously: it provides the differential function, achieves a differential ratio of approximately 0.5 for extended speed range operation, and enables in-line packaging with the hydraulic unit, eliminating the need for separate gearing mechanisms
2Adaptability or versatility
If a two ring gear configuration is used, then the differential ratio is fixed at one (1), but this limits the transmission to lower input speed range
Solution Approach 1:
The patent changes the differential ratio parameter from 1.0 to approximately 0.5 by transitioning to a sun gear configuration, which fundamentally expands the operational speed range of the transmission system
Solution Approach 2:
The patent transitions from a side-to-side packaging arrangement to an in-line/coaxial packaging dimension, allowing the differential and hydraulic unit to be arranged along the same axis, which simplifies the overall packaging and enables the improved speed range
3Area of stationary object
If a two ring gear configuration is used, then the differential must be side-to-side with hydraulic unit, but this forces specific packaging arrangements and increases size
Solution Approach 1:
The patent merges the differential and hydraulic unit into a compact in-line arrangement, eliminating the need for separate gearing between them and reducing the overall footprint of the front region
Solution Approach 2:
The patent repositions the differential and hydraulic unit from a side-to-side two-dimensional arrangement to an in-line three-dimensional coaxial arrangement, which optimizes space utilization and reduces the front region size
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
Enables the integrated drive generator to operate over an extensive speed range and reduces the size of the front region, allowing for coaxial packaging and efficient conversion of variable engine speed to constant generator speed.
Implementation Method 1
A sun gear configuration for an integrated drive generator with a differential ratio of approximately 0.5, allowing for a wider input speed range
Implementation Method 2
The accessory drive gear comprises a gear body having an outer diametric edge, an inner diametric wall, and an inner diametric edge, wherein the outer diametric edge includes a plurality of outer gear teeth
Data Source
AI summary
Embodiments herein relate to piece-part, sub-assembly, assembly, and component levels of a differential composed of a sun gear configuration and utilized in an integrated drive generator. An integrated drive generator is a hydro-mechanical transmission that drives a synchronous salient pole generator. The integrated drive generator is a constant speed output, variable speed input transmission that includes the differential and a hydraulic unit. In general, the integrated drive generator utilizes the variable speed input from an accessory gear box of an engine to drive or control a hydraulic unit, which in turn drives or controls a churn leg member of the differential. As the differential is driven, speeds of each speed member of the differential are then summed to generate the constant speed output to drive the synchronous salient pole generator.