Gas Turbine Accessory Gearbox Tower Shaft Maintenance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In gas turbine engines, the removal and replacement of the tower shaft require disassembly of the accessory gearbox and layshaft housing, complicating maintenance and repair processes.
Innovation Solution
The integration of the tower shaft housing with the main gearbox housing and the use of a bevel gear system allows for the tower shaft to be disassembled without removing the gearbox, by positioning the bevel gear away from the end of the tower shaft, enabling non-parallel alignment and simplifying the assembly and disassembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tower shaft is connected to the layshaft through a separate tower shaft housing, then the structural integrity and drive transmission are ensured, but the maintenance complexity increases because the accessory gearbox and layshaft housing must be disassembled to remove or replace the tower shaft
Solution Approach 1:
The invention divides the housing structure into separable segments: the accessory gearbox housing and the layshaft housing. This allows the layshaft housing to be independently removed, providing access to the tower shaft for maintenance while preserving the integrity of the main gearbox structure. The segmentation enables selective disassembly of only the necessary components during maintenance operations.
Solution Approach 2:
The invention extracts the layshaft housing as a separate removable component from the accessory gearbox assembly. This extraction allows maintenance personnel to access and service the tower shaft by removing only the layshaft housing, without needing to disassemble the entire accessory gearbox. The extracted housing serves as an access pathway that can be independently removed and reinstalled.
2Device complexity
If the tower shaft housing is formed integrally with the main gearbox housing, then the number of parts is reduced, but the ease of operation deteriorates because the entire gearbox must be disassembled to access the tower shaft
Solution Approach 1:
The invention segments the housing structure by providing a removable layshaft housing that is distinct from the main accessory gearbox housing. This segmentation creates an accessible pathway to the tower shaft while maintaining a relatively simple overall structure. The layshaft housing acts as a separate access point that can be removed independently, balancing structural simplicity with maintenance accessibility.
3Device complexity
If the bevel gear is positioned at the end of the tower shaft, then the drive transmission is compact, but the ease of repair worsens because the gear obstructs removal of the tower shaft from the housing
Solution Approach 1:
The invention segments the housing removal process by providing a removable layshaft housing that provides access to the tower shaft. This segmentation allows the tower shaft to be accessed and removed from the housing through the separated layshaft housing, eliminating the obstruction problem caused by the bevel gear position. The segmented housing structure creates an access pathway that bypasses the gear interference issue.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An accessory gearbox (60) for a gas turbine engine has a main gearbox housing (188) for receiving a plurality of gears (66) to drive a plurality of accessories. An input shaft (181) has a first bevel gear (180) at an outer end, and extends inwardly to transmit rotation to the plurality of gears (66). A tower shaft (184) has a second bevel gear (182) engaging the first bevel gear (180) to in turn drive the input shaft (181). A tower shaft housing (186) is fixed to the main gearbox housing (188). A method of removing a tower shaft is also disclosed.