Simulation Analysis of the Oil Distribution and Churning Loss of a Planetary Gear Train in Splash Lubrication

It is extremely complex that the splash lubrication behavior of a planetary gearbox. The information of gear splash lubrication characteristics obtained by test method is limited. This report introduces a CFD model for the prediction of the churning loss and oil distribution characteristics of a planetary gearbox. Firstly, based on the Moving Particle Semi-Implicit Method (MPS) method, a splash lubrication simulation model of the planetary gear train was established. Then the influence of the planet carrier speed on the oil distribution, the number of oil particles in the engagement zones and the churning losses of different rotational components were studied. The results showed that in the rotation of the planetary gear train, the interior space of the gearbox could be divided into three regions: the oil-pool region, the oil-dragging region, and the oil-poor region. In the process of the planet gear passing through the three regions one by one, both the number of oil particles in different engagement zones and the churning torque of each rotational component fluctuated periodically. Finally, the effect of planetary speed on the fluctuations of the churning loss was analyzed.