Auxiliary Oil Feed for Planetary Gears Under Misalignment
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Solution Overview
Problem
Planetary gear trains in aircraft engines face component breakage and wear due to misalignments, which are exacerbated by manufacturing imperfections and aircraft maneuvers, leading to increased maintenance costs and reduced operational efficiency.
Innovation Solution
A lubricating system for planetary gear trains that includes a rotating carrier with a lubricant input system, featuring a stationary bearing and a rotating bearing with conduits for lubricant flow, and a spray bar for direct lubrication of planetary gears and ring gear, designed to accommodate misalignments and reduce wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If gear train components are made larger to reduce wear and breakage, then component strength and wear resistance are improved, but the compactness of the planetary gear train is compromised
Solution Approach 1:
The lubrication system is segmented into multiple independent lubricant supply lines, each serving specific gear components. This allows targeted lubrication of high-stress areas without requiring overall enlargement of the gear train components.
Solution Approach 2:
A lubricant acts as an intermediary substance between gear surfaces, reducing direct metal-to-metal contact and wear. The lubrication system delivers this intermediary to critical interfaces, enabling smaller component dimensions while maintaining wear resistance.
2Strength
If flexible couplings are used to reduce stresses from misalignments, then stress on gear components is reduced, but the coupling complexity and additional lubrication requirements increase
Solution Approach 1:
The lubrication system serves multiple functions simultaneously: it lubricates gear teeth, journal bearings, and flexible coupling elements through a unified multi-branch delivery network, reducing the need for separate lubrication systems for each component.
Solution Approach 2:
The lubrication system merges the lubrication of the flexible coupling with the gear train lubrication system, eliminating the need for separate lubrication infrastructure and reducing overall system complexity despite the added flexibility components.
3Reliability
If high strength materials and wear resistant coatings are used, then component wear resistance is improved, but the cost of the gear train increases
Solution Approach 1:
Instead of applying expensive high-strength materials and wear-resistant coatings to entire gear components, the lubrication system delivers protective lubricant precisely to the local contact zones where wear occurs, achieving wear resistance through targeted lubrication rather than universal material enhancement.
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
The lubricating system effectively reduces wear and breakage of gear components by ensuring consistent lubrication, even under conditions of misalignment, thereby enhancing the reliability and longevity of the gear train while maintaining the compactness and efficiency required for aircraft engines.
Implementation Method 1
A lubricating system for planetary gear trains that includes a rotating carrier with a lubricant input system
Data Source
AI summary
In an embodiment of the present disclosure, a gas turbine engine includes a fan, a first compressor stage and a second compressor stage, a first turbine stage and a second turbine stage, and wherein said first turbine stage drives said second compressor stage as a high spool, and wherein said second turbine stage drives said first compressor stage as part of a low spool, and a gear train driving said fan with said low spool, and such that said fan and said first compressor stage rotate in the same direction, and wherein said high spool operates at higher pressures than said low spool.