Planet Gear Layshaft Geometry for Grinding Access and Compact Gearboxes
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Solution Overview
Problem
Current planet gear designs for turbine engine power gearboxes do not account for the size of grinding wheels during manufacturing, leading to inefficiencies in weight reduction and size minimization while maintaining torque transfer capabilities.
Innovation Solution
The design incorporates a layshaft with a Lambda shape, featuring a Radial Stage Distance that ensures the grinding wheel can access the gear teeth without interference, allowing for a more compact gearbox assembly and reduced axial length, which in turn reduces the overall weight and increases efficiency of the turbine engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional planet gear designs are used without considering grinding wheel size, then the gearbox can be manufactured with standard processes, but the axial length and weight cannot be minimized due to interference with grinding operations
Solution Approach 1:
The layshaft is designed with a Lambda shape configuration before manufacturing, creating sufficient radial stage distance (30-100mm) between the first stage planet gear and second stage planet gear. This preliminary geometric arrangement ensures that grinding wheels can access the gear teeth without interference, while simultaneously enabling a more compact axial length of 150-300mm for the overall planet gear assembly.
2Ease of manufacture
If the radial stage distance is increased to accommodate grinding wheels, then manufacturing accessibility is improved, but the overall size and weight of the gearbox increase
Solution Approach 1:
The invention optimizes the radial stage distance parameter to a specific range of 30-100mm, which is sufficient to accommodate grinding wheel operations but constrained to minimize the overall gearbox size. This parameter optimization, combined with the Lambda-shaped layshaft design, achieves the balance between manufacturing accessibility and weight reduction, resulting in a compact gearbox assembly with axial length of 150-300mm.
3Weight of moving object
If the axial length of the layshaft is reduced for compactness, then the gearbox becomes more lightweight, but the structural support and grinding access are compromised
Solution Approach 1:
The layshaft is designed with an asymmetric Lambda shape configuration, where the radial portion and axial portion are positioned at specific angles to each other. This asymmetric geometry provides sufficient radial stage distance (30-100mm) for grinding wheel access and structural support, while minimizing the axial length to 150-300mm. The asymmetric design allows the layshaft to maintain structural integrity and support capabilities despite the reduced axial dimensions.
Data Source
AI summary
A gearbox assembly includes a plurality of planet gears. At least one planet gear of the plurality of planet gears includes a layshaft that supports a first stage planet gear and a second stage planet gear. The at least one planet gear is characterized by a Radial Stage Distance greater than or equal to 30 millimeters and less than or equal to 100 millimeters. The Radial Stage Distance is Rrm1−Rrt2. Rrm1 is a first stage rim inner radius of the first stage planet gear and Rrt2 is a second stage root radius of the second stage planet gear.