Numerical modeling of the power losses in geared transmissions: Windage, churning and cavitation simulations with a new integrated approach that drastically reduces the computational effort

Energy savings and efficient design are the new global trends. Gears are the main components in many applications like vehicle transmissions, industrial gearboxes etc. and although they are already highly efficient, there is still margin for improvement. Depending on the sector of application, energy saving produces also additional benefits such as a reduction of the pollutant emission in the automotive branch or an increased reliability/power density in compact applications like the precision planetary gearboxes. To perform efficiency improvements it is important to be able to compare different design solutions. A lot of research was made on gears but still today accurate power loss models are not available. Recently, the adoption of numerical techniques has enabled the overcoming of this problem but with the drawback of very long computational times. Considering the importance of such topic for gearbox manufacturers, the authors have developed a specific power loss calculation-tool that enables a good prediction accuracy with reasonable computational efforts. The model was validated with experimental tests performed by FZG showing good agreement.