Eccentric Oil Gutter Layout for Low-Churning Epicyclic Gearboxes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Concentric oil gutters in epicyclical gear trains for gas turbine engines lead to uneven oil distribution, causing windage losses and oil churning due to varying oil levels, which increases the gearbox size and leaves unnecessary space.
Innovation Solution
Positioning the oil gutter eccentrically with respect to the gear train's center of rotation maintains a uniform distance between the oil surface and rotor, reducing windage losses and churning while minimizing the gearbox size by eliminating excess space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a concentric oil gutter is used in the epicyclical gear train, then the gutter can be easily manufactured with uniform geometry, but the oil distribution becomes uneven causing windage losses and oil churning
Solution Approach 1:
The patent applies asymmetry by positioning the oil gutter eccentrically relative to the rotor center, creating a non-uniform geometric configuration. This asymmetric positioning ensures that the gutter maintains a uniform radial distance from the rotor surface throughout rotation, preventing oil accumulation and eliminating windage losses while improving oil distribution uniformity
2Reliability
If the gutter is sized to accommodate maximum oil volume, then windage losses are avoided, but the gearbox size increases with excess space
Solution Approach 1:
The eccentric gutter positioning creates a compact configuration where the gutter closely follows the rotor perimeter throughout rotation. This asymmetric arrangement eliminates excess space while maintaining reliable oil collection, reducing gearbox volume without compromising windage loss prevention
3Ease of operation
If the gutter is positioned radially outward from the rotor, then oil collection is effective, but uneven distance variation causes oil level fluctuations and churning
Solution Approach 1:
The patent resolves this contradiction by eccentrically positioning the gutter such that although the gutter center is offset from the rotor center, the radial distance from the rotor surface to the gutter inner surface remains constant throughout rotation. This asymmetric configuration ensures stable oil levels and effective oil collection simultaneously
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 eccentric gutter design ensures consistent oil distribution, minimizing windage losses and churning, and reduces the overall size of the gearbox by optimizing the distance between the rotor and oil surface across the entire circumference.
Implementation Method 1
As the gears of the epicyclical gear train rotate during operation, the oil is expelled outwardly by inertial (or centrifugal) forces.
Data Source
AI summary
A gearbox for a gas turbine engine. The gearbox including a rotor and a gutter. The oil system is configured to supply oil to the gearbox. The rotor is rotatable about a rotation axis. The rotor expels oil radially outward when the rotor rotates. The gutter is positioned radially outward of the rotor to collect oil expelled by the rotor when the rotor rotates. The gutter is positioned eccentrically with respect to the rotor.