Additive manufacturing technologies for next-generation powertrains

The paper addresses the prototypical development and implementation of an innovative and functionally integrated gear stage for next-generation electric vehicles, produced by using Laser Beam Melting (LBM) and Fused Deposition Modeling (FDM). Two new design targets are addressed by our approach: Oil-free operation is achieved by innovative coating of gear teeth which enables almost maintenance-free operation. Furthermore, a higher damping of sound transmission from tooth mesh to bearings is implemented by an optimal wheel body geometry that is realized by a combination of printable carbon-containing polymers (flange) and steel (gear rim). The innovative approach is to extend components by areas that cannot be produced by milling and casting, e.g. complex structures, contour-following fluid-carrying cooling elements by means of LBM, thus creating a significant benefit compared to state-of-the-art gearboxes. Function integration made possible by additive manufacturing results in a very high component complexity. It is combined with gear grinding and final ta-C coatings ensuring maximum efficiency in dry operation, to achieve economically viable production processes. The increase in tooth mesh efficiency is achieved by optimization approaches in the design to minimize heat losses while at the same time maintaining highest possible strength and lowest noise emission.