Analysis And Experiment Of The Load-split Planetary Gear Train

In recent years, closed planetary gear train has been widely used in large machinery industry (such as crane, ship, aircraft and wind power generation) because of the advantages of small size, high ratio of transmission, big torque, and high transmission efficiency. It is necessary to do more research on the kinematics and structure of closed planetary gear train to improve its efficiency and stability. A simulation experimental platform on closed planetary gear train is built in this paper. And on this basis, dynamic characteristics of the transmission system (including kinematics, ratio of transmission, efficiency, circulating power and engaging frequency) are studied with the comprehensive method of theoretical analysis, finite simulation and experimental method. The contents of the study are as follows:Firstly, a closed planetary gear train transmission model with load-splitting characteristic was established. On this basis, the kinematic relationship between the first and the second stage planetary gear train was analyzed, in order to acquiring the speed corresponding relationship among sun gear, planetary gear and inner gear ring; the relationship between the global transmission ratio and the characteristics of first and second stage planetary gears was inferred with the planetary gear mechanism conversion method, acquiring the variation of the global transmission ratio with the characteristics of the first and second stage planetary gears.Then, the efficiency formula was derived in the way of analyzing efficiency of the load-split closed planetary gear train; the circulating power and power direction inside of the system were analyzed to verifying the rationality of the system; the engaging frequency of the first and second stage transmission system corresponding to different speed was calculated with engaging frequency formula; the finite model of closed planetary gear train was established based on ANSYS, acquiring low order natural frequency of the gear train.Last but not least, a simulation experimental platform on load-split closed planetary gear train was built, as the basis of carrying out efficiency experiment and modal experiment. The efficiency experiment was carried out, and the relationship between the efficiency and speed & load was obtained by variable-controlling approach, which provided guidance for the design and operation of the transmission system. The modal experiment was carried out, in order to obtain the amplitude frequency characteristic curve, phase frequency characteristic curve, and low order natural frequency of the gear train. The result of experiments was compared with the result of theoretical analysis to verify the stability of the transmission system, which could be used as the basis for the optimization design of transmission system.