Design of topological flank modifications to optimize the operational behavior of stepped planetary gear stages in dynamic operating conditions under consideration of producibility

• Applicants: Professor Dr.-Ing. Christian Brecher; Dr.-Ing. Jens Brimmers
• Subject Area: Engineering Design, Machine Elements, Product Development ; Acoustics
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 501245855

One challenge in the design of automotive gearboxes is the combination of high power density, high efficiency and low noise emission. With the electrification of the powertrain, the requirements in terms of noise emission and efficiency increase additionally, since on the one hand the masking noise of the internal combustion engine is eliminated and on the other hand the focus is on energy efficiency for electrically driven vehicles. To meet these requirements, complex gearbox topologies with planetary gear stages are increasingly being used. As the latest development stage of planetary gear stages, stepped planetary gear stages represent a potential alternative to solve the current challenges in gearbox technology. Current research shows the pronounced misalignment behavior of planetary gear stages, especially with manufacturing or assembly deviations. However, the effects of dynamic misalignment behavior on tooth contacts in stepped planetary gears have not been adequately researched. Methods for the optimization of the operational behavior under consideration of manufacturing or assembly deviations with focus on the contact conditions in the gear meshes and tooth flank modifications are missing. The objective of this project is therefore a method for the design of topological tooth flank modifications for the optimization of the dynamic operational behavior of stepped planetary gear stages, taking into account the producibility in the generating grinding process. The result of this project is a validated method for the design of tooth flank modifications to optimize the operational behavior of stepped planetary gear stages with manufacturing or assembly deviations. Due to its general contact description, the method allows the optimization of the operational behavior of a wide range of gear configurations (single/multi-stage cylindrical gears, planetary gear stages, combined gear systems). As an interface between dynamic multi-body simulation (MBS) and quasi-static tooth contact analysis (TCA), the method allows direct consideration of the highly detailed overall system in the design of tooth flank modifications. The operational behavior is evaluated in terms of noise excitation, the load-carrying capacity (tooth flank pressure and tooth root stress) as well as the efficiency and optimized algorithm-based, taking into account a weighting of the objective variables.

• DFG Programme: Research Grants