Turbomachine Drive Gearbox Layout for Compact Multi-Speed Outputs
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Solution Overview
Problem
Conventional drive gearboxes for aircraft turbomachines are bulky, difficult to manufacture, and prone to side displacements when using bevel gears, which complicates the optimization of rotational speeds for multiple equipment and increases aerodynamic drag due to larger diameters.
Innovation Solution
A drive gearbox with a main shaft featuring a bevel gear that drives multiple pieces of equipment at the same speed, combined with a gear set of cylindrical gearwheels that can drive equipment at different speeds, extending over an angular sector to reduce axial dimensions and simplify design, while being securely attached to prevent side movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If bevel gears are used to drive multiple pieces of equipment, then the overall dimensions of the gearbox are reduced, but the manufacturing difficulty increases and side displacements occur
Solution Approach 1:
The gearbox is segmented into two distinct functional parts: a bevel gear section for driving equipment requiring the same speed, and a cylindrical gearwheel section for driving equipment requiring different speeds. This segmentation allows each part to be optimized independently, reducing manufacturing difficulty while maintaining compact dimensions.
Solution Approach 2:
Different regions of the gearbox are assigned different gear types based on local requirements. The bevel gear is placed where symmetric equipment needs identical speed, while cylindrical gearwheels are used where equipment needs variable speeds. This local differentiation resolves the manufacturing complexity issue.
2Area of moving object
If bevel gears are used to drive two pieces of equipment symmetrically arranged, then the radial dimensions are reduced, but the rotational speed optimization for each equipment is compromised
Solution Approach 1:
The gear system is divided into two segments: bevel gears for symmetric equipment requiring identical speeds, and cylindrical gearwheels for equipment requiring different speeds. This segmentation enables both radial compactness and speed adaptability.
Solution Approach 2:
The gearbox is designed with multi-functionality, accommodating both symmetric and asymmetric equipment drive requirements within a single compact structure, allowing different speed optimization scenarios.
3Area of stationary object
If the gearbox is arranged in the inter-jet zone, then the nacelle diameter is reduced, but the axial dimensions must be minimized to avoid heat radiation from combustion chamber
Solution Approach 1:
The gear set is arranged to extend over an angular sector rather than axially, utilizing the circumferential dimension to distribute outputs. This dimensional reorientation reduces axial length while maintaining multiple output capabilities, fitting the inter-jet zone constraints.
4Adaptability or versatility
If cylindrical gearwheels with successive engagement are used, then the rotational speed can be adapted to each equipment, but the gearbox becomes bulky and increases aerodynamic drag
Solution Approach 1:
Instead of arranging gearwheels in a linear axial succession that increases length, the gear set is configured to extend over an angular sector, utilizing circumferential space. This reduces the axial footprint and overall volume while preserving speed adaptation capability.
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 configuration reduces the overall dimensions of the gearbox, allows for optimal speed adjustment of each equipment, and enhances stability, facilitating integration into the turbomachine's inter-jet space without affecting air flows or heat radiation.
Implementation Method 1
the main shaft comprising at least one bevel gear rotationally driving at least one piece of equipment
Implementation Method 2
a gear set with cylindrical gearwheels comprising an input connected to the rotational drive to the main shaft and comprising a plurality of outputs each intended to drive a piece of equipment
Data Source
AI summary
A drive gearbox for turbomachine equipment, the drive gearbox having a main shaft intended to be rotationally connected to a power transmission shaft of a turbomachine. The main shaft has at least one bevel gear rotationally driving at least one piece of equipment. The gearbox has gear set with cylindrical gearwheels that have an input connected to the rotational drive to the main shaft and a plurality of outputs each intended to drive a piece of equipment. The gear set extends over an angular sector and the outputs are angularly spaced apart along the angular sector.