Planetary Reduction Gear Oil Deflection to Reduce Aeration
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Solution Overview
Problem
In dual-flow turbojet engines with planetary reduction gears, the efficient recovery and channeling of lubricating oil is hindered by centrifugal discharge back into the gear, leading to aeration, foaming, and increased heat exchange, which complicates lubrication and oil management.
Innovation Solution
An annular deflector is integrated around the ring gear to reroute centrifugally discharged oil into an offset annular gutter, capturing and directing it into a chamber for efficient collection and re-injection, reducing splashing and allowing for increased gutter volume without altering the enclosure space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gutter is placed around the ring gear to recover oil, then oil recovery is improved, but oil bounces back into the reduction gear and aeration/foaming occurs
Solution Approach 1:
The invention moves the gutter from a planar position at the periphery of the ring gear to an axial dimension by placing it on the downstream face of the ring gear. This spatial repositioning changes how oil is captured - instead of trying to contain radially discharged oil at the periphery, the gutter collects oil axially on the face of the ring gear, preventing bounce-back and aeration while maintaining effective oil recovery
Solution Approach 2:
The invention introduces an oil deflector as an intermediary element between the ring gear and the gutter. The deflector is positioned to receive oil discharged from the ring gear and redirect it toward the gutter, preventing direct contact between high-speed oil and the gutter walls that would cause aeration and foaming
2Quantity of substance
If the gutter volume is increased to store more oil, then oil retention is improved, but the enclosure space requirement increases
Solution Approach 1:
The invention nests the gutter within the existing structure by placing it on the downstream face of the ring gear, utilizing the existing radial and axial clearances. The gutter is positioned within the space between the ring gear downstream face and the enclosure, effectively using already-available space rather than requiring additional enclosure volume
Solution Approach 2:
The invention exploits the axial dimension on the downstream face of the ring gear to accommodate the gutter, rather than requiring additional radial or longitudinal space. This allows the gutter to be positioned within the existing enclosure boundaries while still providing sufficient volume for oil retention
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 solution effectively captures and channels lubricating oil, reducing aeration, foaming, and heat exchange, while maintaining the existing space requirements, thereby enhancing oil management and reducing oil consumption in the lubrication circuit.
Implementation Method 1
an annular deflector fixed to the ring gear and configured to route the oil exiting radially towards the outside of the ring gear up to the gutter by virtue of centrifugal forces
Implementation Method 2
the oil circulating in the reduction gear to lubricate the rolling elements and toothings is discharged at the periphery by centrifugation through the ring gear
Data Source
AI summary
A planetary reduction gear (10) for an aircraft turbine engine, said reduction gear comprising a rotatable sun gear, a rotatable ring gear (9) and satellite gears meshed with the sun gear and the ring gear and carried by a planet carrier intended to be fixed to a stator, the reduction gear further comprising an annular trough for recovering and channelling lubrication oil that is mounted around the ring gear, characterised in that the reduction gear further comprises an annular deflector (22) fixed to the ring gear and configured to route the oil exiting radially towards the outside of the ring gear up to the trough by virtue of centrifugal forces, the trough comprising an annular chamber (18) which is axially remote relative to a median plane (P) substantially passing through the centre of the ring gear, and an annular duct (20) located on a side of said chamber and emerging in said chamber.