Dynamic load distribution of planetary gear sets subject to both internal and external excitations

Planetary gearsets are widely used in several mechanical systems and have numerous advantages over counter-shaft gears. Despite this, the complex arrangement of components in a planetary gear system makes them susceptible to noise and vibration issues. An exhaustive and rich literature is available on the topic of planetary gear dynamics, but most of these studies consider only the parametric excitation of gear mesh contacts while assuming an ideal power source. But contrary to this popular assumption, realistic power sources (IC Engine, electric motor, wind turbine, etc.) could be subjected to torque fluctuations based on the operating conditions. The current study presents a theoretical investigation on the load distribution and dynamic behavior of planetary gear sets subjected to both internal and external excitations. A three-dimensional dynamic planetary load distribution model that inherently captures the internal excitation due to the elastic gear mesh contacts is employed in this study. The influence of operating conditions on both system-level response and local gear mesh contact stress distribution are explored. Discussed results not only illustrate the potential of the dynamic model but also reinforce the need for such computationally efficient models for design and analysis purposes.