Reducer Shaft Cooling Core With Frustoconical Oil Cavities
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Solution Overview
Problem
Current mechanical gearboxes in turbomachines face challenges in effective lubrication and cooling, leading to oil recirculation, particle transition, and structural stiffness issues, particularly in high-dilution ratio dual-flow turbomachines.
Innovation Solution
The introduction of a deflector with concave cylindrical surfaces and projecting tongues to prevent oil recirculation between satellite propellers, combined with a lubrication and cooling core featuring frustoconical flanges for efficient oil circulation and cooling, addresses these challenges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional shaft design is used, then the structure is simpler, but oil recirculation occurs and cooling efficiency deteriorates
Solution Approach 1:
The shaft is segmented into multiple functional zones using frustoconical flanges that create distinct annular cavities for oil circulation. These segments allow oil to flow through specific paths (first cavity from input to output, second cavity return path) preventing recirculation and improving cooling efficiency without requiring a completely redesigned shaft structure.
Solution Approach 2:
Frustoconical flanges are introduced to create three-dimensional annular cavities within the shaft structure. This dimensional approach allows oil to circulate through volumetric spaces rather than simple linear paths, enabling effective cooling while maintaining structural integrity and compatibility with existing shaft designs.
2Object-generated harmful factors
If no deflector is used, then the device is simpler, but oil recirculation and particle transition occur between satellite propellers
Solution Approach 1:
The deflector is designed with tabs that extend into the inter-helix grooves of satellite gears to extract and block oil flow paths that would otherwise cause recirculation. By positioning these tabs strategically in the grooves, oil is prevented from transitioning between front and rear helices, eliminating harmful recirculation and particle transfer while maintaining relatively simple deflector geometry.
3Strength
If the shaft structure is stiffened, then structural rigidity improves, but lubrication and cooling efficiency may deteriorate
Solution Approach 1:
The shaft incorporates frustoconical flanges with specific geometric properties (cone angles, cavity dimensions) optimized for oil circulation in specific regions. These localized structural features provide the necessary rigidity while simultaneously creating effective lubrication and cooling channels, ensuring both structural strength and functional efficiency are achieved in the same component.
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 enhances oil evacuation, limits particle transitions, stiffens the structure, and improves lubrication and cooling efficiency, reducing vibration and pressure loss while being compatible with various gearbox types and tooth configurations.
Implementation Method 1
a lubrication and cooling core (22), mounted in said shaft, characterized in that the core comprises first and second coaxial and frustoconical flanges (22a, 22b)... define with it two annular cavities (24) for the circulation of lubricating and cooling oil for this shaft
Data Source
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AI summary
Lubrication and cooling core (22) for a mechanical turbomachine reducer, in particular for aircraft, characterized in that it is intended to be mounted in a shaft (10b) of a satellite of said reducer, and comprises coaxial and substantially frustoconical first and second flanges (22a, 22b) each having a first end of larger diameter and a second opposite end of smaller diameter, the flanges being fixed together by their second ends and being intended to extend inside said shaft and to cover at least one radially internal surface (10e, 10f) of this shaft to define with it at least one annular cavity (24) for the circulation of lubricating and cooling oil of this shaft, said second ends of said first and second flanges having fluidic connection means of said at least one cavity to a source of lubricating and cooling oil.