Fan Drive Gear Carrier Assembly With Unitary Housing Rigidity
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Solution Overview
Problem
Existing fan drive gear systems in gas turbine engines face challenges in achieving improved strength and rigidity, particularly in epicyclic gear trains with split carrier housings, which can compromise the structural integrity and require complex lubrication systems.
Innovation Solution
The assembly of a fan drive gear system with a unitary carrier housing and integrated lubrication system, utilizing a unitary carrier structure and a flexible input coupling to enhance structural strength and rigidity, while simplifying lubricant distribution through baffles and manifold segments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a split carrier housing is used in epicyclic gear trains, then assembly is simplified and manufacturing is easier, but structural strength and rigidity are compromised
Solution Approach 1:
The carrier housing is divided into two separable halves that can be assembled around the gear train components and then joined together. This segmentation allows for simplified assembly where components can be installed in the carrier halves before final joining, resolving the contradiction between ease of assembly and structural integrity.
2Strength
If a unitary carrier housing is used, then structural strength and rigidity are improved, but assembly complexity and manufacturing difficulty increase
Solution Approach 1:
The unitary carrier housing design is segmented into two halves for assembly purposes, allowing components to be installed before joining. This maintains the structural benefits of a unitary construction while reducing assembly complexity through the separable halves approach.
3Reliability
If complex lubrication systems are used in gear trains with split carrier housings, then lubrication coverage is improved, but system complexity and weight increase
Solution Approach 1:
The gear train components are designed to distribute lubricant to themselves through their own rotation and movement, eliminating the need for complex external lubrication systems. The rotating gears and carriers automatically pick up and distribute lubricant throughout the gear train, achieving reliable lubrication coverage while minimizing system complexity.
Data Source
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AI summary
A method of assembling a fan drive gear system for a gas turbine engine includes providing: a unitary carrier (134) defining a central axis and that includes spaced apart walls (160) and circumferentially spaced mounts (154) defining spaced apart apertures at an outer circumference of the carrier (134), gear pockets defined between the walls (160) and extending to the apertures, and a central opening (200) in at least one of the walls (160); inserting a plurality of intermediate gears (132) through the central opening (200); moving the intermediate gears (132) radially outwardly relative to the central axis into the gear pockets; inserting a sun gear (128) through the central opening (200); and moving the plurality of intermediate gears (132) radially inwardly relative to the central axis to engage the sun gear (128), and coupling a fan shaft to the carrier (134) such that the fan shaft and intermediate gears (132) are rotatable about the central axis.