Design and investigation of 5-axis machined double helical gears for aerospace applications

 

Starting Situation

Both economic and environmental goals call for efficiency improvements to reduce pollutant emissions in the civil aviation industry. Turbine efficiency can be increased primarily by increasing the bypass ratio. This is possible, for example, by increasing the turbine diameter, which, however, increases the centrifugal forces on the turbine blades at the same turbine speeds. In order to decouple the speed of the turbine from the speed of the engine fan, the use of a gearbox is necessary. Due to the high power density and the resulting optimization of installation space, double helical gears are used in these planetary gears.

Research Objective

The aim of the project is to optimize the gear geometry with regard to the power-to-weight ratio by means of a five-axis machining by means of FE simulation, taking into account the manufacturability, and to store manufacturing and functional information in a digital twin. Both the groove and the tooth root design of the double helical gearing will be optimized. The reduction of the groove width provides a potential for weight reduction. The optimization of the tooth root geometry allows the transmission of higher torques. Compared to conventional gear cutting methods, flexible 5-axis kinematics in particular provide the ability to increase the above-mentioned potentials. One partial goal is the generation of CAD models using FEM-optimized gear geometries, which are transferred to CAM planning via suitable interfaces.

A further subgoal is the exact characterization of the edge zones of the manufactured components. The characterization is a prerequisite for the analysis of the load capacity of the gears and the linkage of the influence of manufacturing parameters on the resulting service life from test bench tests.