Potentials and limitations in production and use of herringbone gearings for high-performance gearboxes

The development of modern gearing systems requires interdisciplinary and holistic approaches due to the complex correlations between manufacturing and gear properties in applications. To fully exploit the advantages of specific gearing designs, manufacturing processes need to complement each other. Herringbone gearings feature high potential for compact gearbox designs in various applications, e.g., epicyclic arrangements with relatively quiet running properties. Due to the elimination of transverse load and increased strength, gearbox dimensions can be reduced, and their design can be simplified. An advantageous application of herringbone gear design requires joint development of manufacturing process steps and consideration of their influence on operational behavior. The highest challenge lies in the complex and elaborate manufacturing of a real herringbone geometry without a gap in the middle between the left and right gear wheel sides. The present study shows that both gear rolling and power skiving processes show technical feasibility with high quality results and short processing times. Gear rolling leads to a gapless shape of the two sides, whereas power skiving produces a slight degradation in a particular intermediate area while the gear teeth stay interconnected. A calculation approach and a kinematic manufacturing simulation are employed to design the technological process parameters, tool geometry, and resulting gear wheel geometry. Furthermore, the properties of rolled gears’ peripheral zones are discussed, and FEM-assisted transmission errors of the skived gear wheel geometry are analyzed to describe the impact of specific manufacturing processes on gear wheel properties. The results of this work comprise a closed consideration from manufacturing to application properties of gear wheels by combining separate calculation and examination approaches. Future investigations will include a backward design from the operational requirements of the gearing system towards the choice of specific technological process parameters.