Transverse Bevel Gear Accessory Gearbox for Compact Turbine Packaging
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Solution Overview
Problem
Gas turbine engines face challenges in reducing the size of accessory systems, leading to increased drag and nacelle volume, which affects efficiency and mobility, particularly in mobile platforms like aircraft.
Innovation Solution
A compact accessory gearbox system is designed with a unique configuration of bevel gears and shafts that allows for a reduced footprint by optimizing the arrangement of accessories around the gearbox, utilizing transverse and parallel axes to minimize space while maintaining efficient torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If traditional accessory systems are used in gas turbine engines, then accessory functionality is maintained, but nacelle volume increases and drag increases
Solution Approach 1:
The patent employs bevel gears to change the rotational axis orientation from parallel to transverse, arranging accessories in a three-dimensional configuration around the gearbox. This dimensional reorganization reduces the linear footprint and allows more compact packaging of accessories, thereby reducing nacelle volume and associated drag.
Solution Approach 2:
The patent integrates multiple accessories (generator, pump, etc.) into a single compact accessory gearbox assembly, consolidating their mounting space. By combining these components into one integrated unit with shared lubrication and support structures, the overall nacelle volume required is reduced compared to distributed mounting arrangements.
2Volume of stationary object
If accessory size is reduced, then nacelle volume decreases, but torque transmission efficiency may be compromised
Solution Approach 1:
The bevel gear arrangement changes the torque transmission path from a single-axis parallel configuration to a multi-axis transverse configuration. This allows torque to be efficiently transmitted through compact angular gear meshes, maintaining power transmission capability while reducing the linear dimensions and overall volume of the gearbox.
Solution Approach 2:
The patent employs a lubrication system with channels and passages that dynamically deliver lubricant to the bevel gear meshes and bearing surfaces. This dynamic lubrication ensures efficient torque transmission and reduces friction losses in the compact gearbox, maintaining power transmission efficiency despite the reduced size.
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 compact accessory gearbox achieves a significant reduction in nacelle volume, enhancing mobility and efficiency by reducing the overall size of the engine while maintaining the necessary accessory functionality.
Implementation Method 1
The towershaft includes a towershaft bevel gear at a distal end. The accessory system also includes a shaft including a first shaft bevel gear coupled to the towershaft bevel gear.
Data Source
AI summary
An accessory system for a gas turbine engine having a driveshaft with an axis of rotation is provided. The accessory system includes a towershaft coupled to the driveshaft and driven by the driveshaft along a towershaft axis of rotation. The accessory system also includes a shaft including a first shaft bevel gear coupled to a towershaft bevel gear. The shaft is rotatable by the towershaft along a shaft axis of rotation. The shaft axis of rotation is transverse to the towershaft axis of rotation. The accessory system includes a first accessory drive shaft having a first accessory bevel gear driven by the shaft. The accessory system also includes a second accessory drive shaft having a second accessory bevel gear driven by the shaft. A first accessory axis of rotation and a second accessory axis of rotation are substantially transverse to the shaft axis of rotation.