AGMA 25FTM12 ✓ Most Recent [ Active ]

Achieving compact gearbox design requires high-end simulation by local tooth contact analysis. Recent developments show a trend towards more complex planetary gear designs to further increase power density. This can be observed in the field of e-mobility or e-micromobility. For high ratio and small housing dimensions not only classical minus planetary gear stages are designed but also designs with stepped planets are discussed. These designs bear some extra complexity which can be thoroughly analyzed by current algorithms available in specialized gearbox software packages. However, in many cases not only is the optimization of the gear mesh necessary, but the rolling bearing situation under these severe space restrictions proves to be the limiting factor. High radial loads of the smaller gear of the stepped planet may lead to uneven loading of the bearings and even edge loads. Designing a gear microgeometry which ensures even loading of the tooth flank does not solve the issue. One possibility to prevent a steep decrease in bearing lifetime may be an optimization of the gear microgeometry which also includes the influence on the load distribution of the rolling elements within the bearing. Only a local bearing analysis directly linked to the local tooth contact analysis allows a fair evaluation of the situation. The respective algorithms must be formulated with an adapted level of detail to balance the time for modelling and solving between the domains of bearing analysis and gear simulation. In this paper the authors present an approach based on the algorithms implemented in the software package RIKOR. The influence of the level of detail in the simulation of gear mesh on the bearing contact conditions and vice versa is documented in theory and by an example gearbox design.