The effect of planetary gear/star gear on the transmission efficiency of closed differential double helical gear train

The research of transmission efficiency is of great significance for reducing energy consumption and improving the performance of the device. Researchers have done a lot of work on the calculation of transmission efficiency. However, in the present research work, the quantity of planetary gear/star gear is usually not considered and only a planetary gear/star gear is adopted in the gear transmission efficiency. In practice, in order to increase the stiffness and load capacity of gear train, a plurality of planetary gear/star gears is adopted. The closed differential double helical gear train has been widely used in many fields, such as the main reducer of aircraft engine, lifting mechanism, and the power transmission system of marine ships. Therefore, in this paper, the closed differential double helical gear train is taken as the research object and the effect of planetary gear/star gear on the transmission efficiency is analyzed. Firstly, according to the structure of closed differential double helical gear train, related kinematic analysis is given. Secondly, a graph representation is used to characterize the closed differential double helical gear train. According to the theory of virtual power, the power flow direction of closed differential double helical gear train is determined and the value of split power is obtained. According to the input and output values described in graph representation of closed differential double helical gear train, the formula of transmission efficiency is derived and the effects of planetary gear/star gear on transmission efficiency are analyzed. Finally, an illustrative example shows that compared with the theoretical value, the difference considering the effect of planetary gear/star gear on the transmission efficiency of closed differential double helical gear train is two percentage points.