Geared Turbofan Shaft Support for Rigidity and Misalignment
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Solution Overview
Problem
Gas turbine engines, particularly geared turbofan engines, require an effective support system for shaft arrangements driving the gearbox and propulsive fan, as existing designs face challenges in efficiently transferring rotational speed and mechanical loads while optimizing engine efficiency and structural integrity.
Innovation Solution
The gas turbine engine incorporates a gearbox device with a sun gear, planet carrier, and ring gear, featuring an input shaft device with varying rigidity options and an inter-shaft bearing system, along with a fan shaft bearing system, to efficiently transmit torque and loads from the turbine to the propulsive fan, utilizing a combination of roller and ball bearings and adaptive shaft designs to manage mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the input shaft device has high rigidity, then the structural stability is improved, but the ability to accommodate misalignment and reduce mechanical stresses deteriorates
Solution Approach 1:
The input shaft device transitions from a static rigid structure to a dynamic flexible structure that can adapt its deformation characteristics based on operational conditions, allowing it to accommodate misalignment while maintaining stability through controlled elasticity
Solution Approach 2:
The rigidity parameter of the input shaft device is changed from high (rigid) to optimized (flexible), allowing the shaft to deform elastically under misalignment conditions while still providing sufficient structural support for stable operation
2Volume of moving object
If the bearing devices are positioned axially very close to the gearbox device, then the space utilization is improved, but the complexity of precise positioning and alignment deteriorates
Solution Approach 1:
The bearing devices are nested within or integrated with the gearbox device structure, with the inter-shaft bearing system positioned within the gearbox housing and the fan shaft bearing system integrated with the fan assembly, allowing compact arrangement without excessive positioning complexity
Solution Approach 2:
The bearing devices serve as intermediary elements that facilitate the connection between rotating components and stationary structures, simplifying the positioning requirements by providing standardized mounting interfaces and load transfer paths
3Force
If the planet carrier or ring gear is connected to the propulsive fan via an output shaft device, then the mechanical load transmission is improved, but the complexity of the shaft arrangement deteriorates
Solution Approach 1:
The output shaft device merges the functions of multiple shafts into a single integrated component that connects the planet carrier or ring gear to the propulsive fan, reducing the overall complexity of the shaft arrangement while maintaining effective mechanical load transmission
Solution Approach 2:
The output shaft device is designed as a multi-functional component that simultaneously transmits mechanical loads, provides structural support, and enables rotational motion transfer, reducing the need for separate dedicated components for each function
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
This configuration enhances the overall efficiency of the gas turbine engine by reducing rotational speed, improving mechanical properties, and ensuring robust structural support, leading to increased engine performance and efficiency in propulsive thrust generation.
Implementation Method 1
the inter-shaft bearing system comprises at least one ball bearing
Implementation Method 2
the rear carrier bearing device comprises at least one roller bearing and/or the inter-shaft bearing system comprises at least one ball bearing
Data Source
AI summary
A gas turbine engine, in particular an aircraft engine, includes: a turbine connected via an input shaft device to a gearbox device having a sun gear, a planet carrier having a plurality of planet gears attached thereto, and a ring gear, the sun gear is connected to the input shaft device, the planet carrier or the ring gear is connected to a propulsive fan via an output shaft device of the gearbox device, with a rear carrier bearing device radially between the planet carrier and a static structure on the input side of the gearbox device, an inter-shaft bearing system being positioned radially between the input shaft device and the planet carrier of the gearbox device. The input shaft device having a high rigidity or the input shaft device having a diaphragm section.