Fan Drive Gear System With Integrated Accessory Drive
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Solution Overview
Problem
Turbine engines face challenges in improving thermal, transfer, and propulsive efficiencies, particularly in driving accessory components like motors and pumps, which are conventionally coupled to engine shafts, limiting further performance enhancements.
Innovation Solution
A fan drive gear system with a sun gear, intermediate gears, and a ring gear, optionally with flexible couplings, supports accessory components like electric motors or fluid pumps, allowing for efficient gear reduction and alignment adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If accessory components are driven by a coupling to an engine shaft, then the drive mechanism is simple, but the thermal and propulsive efficiencies cannot be further improved
Solution Approach 1:
The accessory component drive mechanism is merged with the fan drive gear system. The sun gear includes a first gear portion that drives the fan and a second gear portion that drives the accessory component, combining two drive functions into a single integrated system rather than separate drive mechanisms
Solution Approach 2:
The sun gear serves multiple functions: it is driven by the engine shaft and simultaneously provides power to both the fan section (through the first gear portion) and the accessory component (through the second gear portion), making it a multi-functional drive element
2Productivity
If a fan drive gear system is used to improve efficiency, then thermal and propulsive efficiencies improve, but the device complexity increases
Solution Approach 1:
The sun gear is segmented into multiple gear portions (first gear portion for fan drive, second gear portion for accessory component drive) that can independently perform different functions, allowing complex drive requirements to be met through a single segmented component rather than multiple separate components
Solution Approach 2:
The epicyclic gear system employs a nested structure where intermediate gears are positioned between the sun gear and ring gear, with the carrier supporting the intermediate gears, creating a compact nested arrangement that achieves gear reduction while maintaining space efficiency
3Stability of the object's composition
If rigid connections are used in the gear system, then structural stability is maintained, but misalignments and movements cannot be accommodated
Solution Approach 1:
A flexible coupling is used to connect the ring gear to the engine shaft, providing a flexible connection that can accommodate misalignments and movements between the engine shaft and the gear system while maintaining the integrity of the drive connection
Solution Approach 2:
The system incorporates flexible elements that allow dynamic adjustment to accommodate misalignments and movements, transforming the connection from a static rigid structure to a dynamic system that can adapt to operational variations
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
Enhances engine performance by optimizing the drive mechanism for accessory components, improving thermal and propulsive efficiencies while accommodating misalignments and movements.
Implementation Method 1
a flexible coupling between the ring gear and the engine shaft
Data Source
Figure 1
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AI summary
A fan drive gear system (48) for a turbine engine (20) includes a sun gear (66) that is configured to be driven by an engine shaft (40) that is rotatable about an axis. The sun gear (66) includes a first gear portion (76) and a second gear portion (78). A plurality of intermediate gears (68) are coupled to the first gear portion (76) of the sun gear (66), a ring gear (70) is coupled to the plurality of intermediate gears (68), a carrier (72) supports rotation of the plurality of intermediate gears (68), and an accessory component (62) is coupled to the second gear portion (78) of the sun gear (66).