Staged Sun Gear Structure for Aircraft Engine Oil Circulation
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Solution Overview
Problem
Current mechanical reduction gears in turbine engines, particularly in aircraft, face challenges in efficiently circulating and evacuating oil, leading to potential overpressure issues that can affect the alignment and lubrication of components.
Innovation Solution
The design incorporates a sun gear with staged profiles and splines that allow for axial centering and lubrication, featuring cylindrical surfaces and bores for oil supply and evacuation, along with an annular recess and oil deflectors to manage oil flow and prevent overpressure, ensuring effective lubrication and alignment of the input shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sun gear design is used, then the structure is simple, but the oil circulation and evacuation is insufficient leading to overpressure issues
Solution Approach 1:
The sun gear is divided into multiple axial sections (first section with first splines, second section with second splines, third section with third splines) where each section has different spline configurations. This segmentation allows oil to be supplied and evacuated through different sections, improving oil circulation efficiency while maintaining a relatively simple overall structure.
Solution Approach 2:
Different axial sections of the sun gear have different spline characteristics (first splines, second splines, third splines) optimized for specific functions. The first section receives oil supply, the second section facilitates oil evacuation, and the third section provides additional lubrication. This local differentiation improves overall oil circulation without requiring complete structural redesign.
2Ease of operation
If simple axial mounting is used, then the mounting process is easy, but the centering precision and oil distribution are insufficient
Solution Approach 1:
The sun gear includes preliminary centering features (centring surfaces on the input shaft and corresponding centring surfaces on the sun gear) that automatically align components during the axial mounting process. This preliminary centering action ensures precise alignment is achieved automatically as part of the simple axial insertion, without requiring separate centering operations.
Solution Approach 2:
The staged spline sections act as intermediaries between the input shaft and the planet gears. The first splines engage first during axial insertion to guide centering, followed by engagement of second and third splines. This staged intermediary engagement ensures precise centering is achieved during the simple axial mounting process.
Data Source
AI summary
A sun gear for a mechanical reduction gear of a turbine engine, in particular for aircraft, the sun gear having a general annular shape about an axis and comprising at the outer periphery thereof, a meshing gearing with planet gears of the reduction gear, and at the inner periphery thereof, splines for coupling with an input shaft of the reduction gear, characterised in that the sun gear has a staged profile in axial cross-section, and preferably comprises an annular recess opening radially inwards and configured to receive at least one oil jet.