The complex shape of gears is very attractive to the near-net-shape PM technology. The strength of conventional PM parts is reduced by the residual porosity due to the power law relationship between the density and the mechanical properties. The maximum stresses in gears are found in the tooth root and the flank near or directly at the surface, so that by a local densification of the near surface layer the maximum load carrying capacity of the complete gear can be increased. This surface densification can be achieved by a rolling process. Due to the own elastic-plastic behavior of PM materials and due to the continuous change of the contact conditions during rolling, the process is too complex to be described analytically. To gain a better understanding of the process, the numerical simulation is a capable method. In this paper an FEA model is prepared and verified based on an experimental investigation. Additionally, case studies were carried out in order to analyze the relationship between the process parameters and the densification result.

The scope of this paper is to establish a method to analyze, design and test mechatronic drive trains based on the application requirements concerning efficiency and energy consumption. The considered drive train consists of frequency inverter, electric motor and gearbox. A standard three phase two-level inverter with two different machine control strategies (constant torque angle CTA and maximum torque per Ampere MTPA) and two different PWM logics (third harmonic injection method and space vector modulation) is considered. As type of the electric machine the permanent magnet synchronous motor (PMSM) with surface mounted magnets or interior magnets is chosen. Additionally, spur, bevel worm and planetary gearboxes can be modeled with this approach. To determine the efficiency a basic model for all components is developed to calculate the respective losses. Finally, an optimization tool is introduced to increase the energy efficiency of an application load cycle by determining the optimal gear ratio for a given frequency inverter and electric motor combination. Finally, the model is used in a case study to calculate the optimal gear ratio by using different types of gearboxes.

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