Gas Turbine Front Support Arrangement for Epicyclic Gear Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Geared architectures in gas turbine engines face challenges that reduce efficiency gains due to disrupted gear alignment caused by operational loads, necessitating improved support structures.
Innovation Solution
A gas turbine engine design featuring a speed reduction device with fan bearings positioned axially forward and aft of the epicyclic gear system, where the outer races of these bearings are fixed relative to the fan hub and inner races are fixed to the engine static structure, along with a carrier that is also fixed, to maintain alignment and reduce misalignment forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a speed reduction device with epicyclic gear system is used to drive the fan section at reduced speed, then propulsive efficiency is improved, but gear alignment is disrupted due to operational loads
Solution Approach 1:
The patent employs dynamic bearing support structures that allow controlled movement and adjustment of gear components during operation. The bearings are positioned and configured to accommodate operational loads while maintaining proper gear alignment, enabling the system to adapt dynamically to varying load conditions rather than relying on rigid fixed positioning.
Solution Approach 2:
The patent introduces intermediate bearing structures as mediators between the gear system and the engine structure. These bearings act as cushioning elements that absorb and distribute operational loads, preventing direct transmission of disruptive forces to the gear alignment while still supporting the speed reduction device effectively.
2Stability of the object's composition
If rigid support structures are used to maintain gear alignment, then alignment stability is improved, but flexibility to accommodate operational loads is reduced
Solution Approach 1:
The patent changes the support parameters from rigid fixed positioning to controlled flexible positioning through bearing selection and arrangement. The bearings are specified with particular clearance and preload parameters that allow controlled movement within defined ranges, maintaining alignment stability while adapting to operational load variations.
Solution Approach 2:
The support structure transitions from static rigid mounting to dynamic bearing-supported mounting that allows controlled movement. The bearings enable the gear components to adjust their positions dynamically in response to operational loads while maintaining proper alignment through the bearing's inherent load-accommodating characteristics.
Data Source
AI summary
A gas turbine engine includes a propulsor section including a propulsor having blades extending from a propulsor hub, and a propulsor shaft that drives the propulsor hub. A compressor section includes a first compressor having a rotatable compressor hub. A speed reduction device drives the compressor hub and the propulsor through a connection established axially forward of the epicyclic gear system relative to an engine longitudinal axis. The epicyclic gear system is straddled by forward and aft bearings that engage a carrier of the speed reduction device.