Planetary Ring Gear Mounting for Balanced Load Distribution
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Solution Overview
Problem
Gas turbine engines face challenges in balancing the load on planetary gears, leading to increased weight and fuel consumption, which affects the efficiency and durability of the engine, especially in aircraft applications.
Innovation Solution
A transmission arrangement with a holding device that includes a first and second section, both having similar torsional stiffness, allowing even load distribution on the ring gear and reducing axial deformation, thereby enhancing durability and reducing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the planetary gear is designed to be particularly solid to withstand stresses and strains, then the reliability and service life are improved, but the weight increases leading to increased fuel consumption
Solution Approach 1:
The patent applies parameter changes by precisely controlling the torsional stiffness of the holding device sections to be equal (ratio 1.0 ± 0.1), which optimizes the load distribution on gear teeth. This allows the gear assembly to achieve sufficient reliability through optimized mechanical parameters rather than simply increasing overall mass, thereby avoiding unnecessary weight increase and fuel consumption.
2Ease of manufacture
If the holding device has unequal torsional stiffness in different sections, then the manufacturing complexity is reduced, but the load distribution on the ring gear becomes uneven increasing tooth stress
Solution Approach 1:
The patent specifies that the first and second sections of the holding device should have equal torsional stiffness with a ratio of 1.0 ± 0.1. This parameter optimization ensures uniform load distribution on the ring gear teeth, reducing peak stresses and improving durability, while maintaining practical manufacturability through defined geometric relationships between section dimensions.
3Reliability
If the torsional stiffness ratio of the first and second sections is within 1.0 ± 0.1, then the load distribution is balanced and service life is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent defines a tolerance range of 1.0 ± 0.1 for the torsional stiffness ratio, which balances manufacturing feasibility with performance requirements. This parameter specification allows sufficient tolerance for normal manufacturing variations while ensuring that the load distribution remains sufficiently balanced to achieve the desired service life improvement, avoiding excessively tight tolerances that would make manufacturing impractical.
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 solution enables a balanced load on the ring gear, reducing tooth stress and allowing for increased durability and reduced weight, leading to improved efficiency and fuel savings in gas turbine engines.
Implementation Method 1
The first and second sections each have a torsional stiffness (in particular with respect to the cross-sectional area along the center axis of the ring gear and/or about an axis perpendicular to the radius and the center axis of the ring gear), the ratio of these torsional stiffnesses being 1.0 +/- 0.1
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A gear arrangement for a gas turbine engine (10) comprises a planetary gear (30) with at least one ring gear (38) and at least one planet gear (32), which, when rolling on the ring gear (38), exerts a force on it in the direction of a force vector (K); and a holding device (40; 40') for attaching the at least one ring gear (38) to another structure (24), comprising a first section (40a) extending axially on one side of the force vector (K) and/or a straight extension thereof, and a second section (40b) extending axially on the other side of the force vector (K) and/or the straight extension thereof. A gas turbine engine and a method for manufacturing a gear arrangement are also provided.