Planetary Gearbox Ring Gear Support for Balanced Load Distribution
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Solution Overview
Problem
Gas turbine engine planetary gearboxes face challenges in balancing load distribution, leading to increased weight and reduced service life due to high torque transmission requirements, which in turn increase fuel consumption, especially in aircraft applications.
Innovation Solution
A gearbox assembly design featuring a planetary gearbox with a holding device having two sections with identical rotational stiffness, allowing balanced loading of the ring gear and planet gears, reducing tooth stress and enabling uniform loading, and incorporating a flexible suspension to decouple loads and prevent tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If planetary gearboxes are made massive to withstand loads during operation, then reliability and service life are improved, but weight increases leading to increased fuel consumption
Solution Approach 1:
The patent changes the structural parameters of the holding device by dividing it into first and second sections arranged symmetrically with respect to the force vector. This parameter change optimizes the load distribution and reduces tooth stress on the ring gear and planet gears, allowing the gearbox to withstand operational loads with reduced mass while maintaining reliability and service life.
2Strength
If planetary gearboxes are made massive to withstand loads during operation, then strength is improved, but weight increases leading to increased fuel consumption
Solution Approach 1:
The holding device is designed with specific geometric parameters including symmetric arrangement of sections and optimized dimensions to achieve the required strength. The first section has dimensions L1, B1, H1 and the second section has dimensions L2, B2, H2, where these parameters are configured to distribute loads evenly and reduce tooth stress, thereby achieving necessary strength with minimized weight.
3Ease of manufacture
If holding device sections have different rotational stiffness, then manufacturing complexity is reduced, but uniform loading cannot be achieved leading to increased tooth stress
Solution Approach 1:
The patent employs a symmetric design principle where the holding device is divided into first and second sections that are symmetrically arranged with respect to the force vector. This symmetry ensures that both sections have identical rotational stiffness, which enables uniform loading distribution and minimizes tooth stress on the ring gear and planet gears during operation.
4Device complexity
If the holding device does not provide balanced loading, then device complexity is reduced, but service life is reduced due to increased tooth stress
Solution Approach 1:
The holding device parameters including the symmetric arrangement of first and second sections, their dimensions (L1, B1, H1 and L2, B2, H2), and rotational stiffness are optimized to achieve balanced loading. This parameter optimization ensures uniform distribution of forces on the ring gear and planet gears, reducing tooth stress and thereby extending the service life of the planetary gearbox.
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
The design enhances the service life and reduces weight of the gearbox assembly by ensuring uniform loading and minimizing axial deformation, thereby improving efficiency and reducing fuel consumption in gas turbine engines.
Implementation Method 1
an elastic deformation of the ring gear due to the force exerted by the planet gear to take place only in the radial direction and only insignificantly or not at all in the axial direction
Data Source
AI summary
A gearbox assembly for a gas turbine engine comprises a planetary gearbox having at least one ring gear and at least one planet gear, which exerts a force on the ring gear in the direction of a force vector as it rolls on said ring gear; and a holding device for fastening the at least one ring gear on another structure, having a first section, which extends in the axial direction on one side of the force vector and/or of a straight-line extension thereof, and having a second section, which extends in the axial direction on the other side of the force vector and/or of the straight-line extension thereof. A gas turbine engine and a method for producing a gearbox assembly are furthermore made available.