Accessory Gearbox Tower Shaft Removal via Segmentation
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Solution Overview
Problem
Conventional gas turbine engine accessory gearboxes are difficult to service and remove due to their design constraints, particularly the need to disassemble complex geartrain components and the lack of flexibility in mounting configurations.
Innovation Solution
The accessory gearbox design features independent bevel gear sets and adaptable mounting configurations, allowing for independent adjustment and configuration, and enables the removal of the tower shaft without removing the gearbox, by using a 2-way bevel gearing arrangement and angled input axis, which simplifies the removal process and provides flexibility in component placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional accessory gearbox design is used, then the gearbox can drive accessory systems at different speeds, but the gearbox is difficult to service and remove
Solution Approach 1:
The accessory gearbox is divided into separable modules: the gearbox case with mounted accessories can remain installed on the engine while the tower shaft and angle gearbox assembly are removed as a separate unit. This segmentation allows servicing of the accessory gearbox without removing the entire assembly from the engine.
Solution Approach 2:
The tower shaft and angle gearbox are extracted as a removable sub-assembly from the main gearbox case. The angle gearbox is positioned to allow the tower shaft to be removed through the gearbox case, enabling maintenance of these components without removing the entire accessory gearbox from the engine.
2Ease of operation
If conventional accessory gearbox design is used, then the gearbox can drive accessory systems, but the gearbox is difficult to remove from the engine
Solution Approach 1:
The accessory drive system is segmented into the stationary gearbox case (remaining on engine) and the removable tower shaft with angle gearbox. This allows the tower shaft assembly to be removed independently from the engine without removing the entire accessory gearbox.
Solution Approach 2:
The angle gearbox serves as an intermediary component that connects the tower shaft to the main gearbox case. Its specific positioning and configuration enable the tower shaft to be extracted through the gearbox case, facilitating removal without complete disassembly of the accessory gearbox from the engine.
3Adaptability or versatility
If conventional accessory gearbox design is used, then the gearbox can be mounted underneath the engine, but there is lack of flexibility in mounting configurations
Solution Approach 1:
The mounting configuration is made adaptable rather than fixed. The gearbox case can be mounted in different positions and orientations on the engine, and the angle gearbox can be positioned at various angles to accommodate different tower shaft configurations. This dynamic adaptability allows the same basic design to serve multiple mounting scenarios.
Solution Approach 2:
The accessory gearbox design incorporates universal features that allow it to function in multiple mounting configurations. The gearbox case with its accessory mounting faces can be oriented differently on the engine, and the angle gearbox arrangement can accommodate various tower shaft angles, making the design versatile for different engine configurations and accessory placement requirements.
Data Source
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AI summary
An accessory system for a gas turbine engine includes an accessory gearbox which defines an accessory gearbox axis and includes first and second sides. A first geartrain includes one or more shafts rotatable about axes perpendicular to the first side of the accessory gearbox and a second geartrain includes one or more shafts rotatable about axes perpendicular to the second side of the accessory gearbox. A driven gear set defines an input axis and drives first geartrain and the second geartrain about corresponding first and second drive axes parallel to the input axis.