Dynamic Characteristics of the Multistage Planetary Gear Transmission System Based on a Stochastic Load

Multistage planetary gear transmission has a large speed ratio, compact structure and large load capacity in engineering practice. However, its vibration affects the performance and reliability of the transmission, especially under a stochastic load condition with different dynamic characteristics. In this context, the dynamic behavior of a four-stage planetary gear transmission system is investigated using the lumped-parameter model. First, the translation-torsion dynamics model of the multistage planetary gear transmission system is established. Then, the natural frequency and the effect of meshing stiffness and component mass on the natural frequency are investigated. Further, the dynamics equation of the planetary gear transmission system is solved by the Runge–Kutta method, and the damped dynamic response with an equivalent load and the dynamic responses with stochastic loads are analyzed. Notably, the displacement amplitude increases with the increment of the stochastic load. In addition, the frequency domain response under 50%, 75%, 100% and 120% of the equivalent torque are studied. Lastly, a test rig is built for a yaw drive in a wind turbine with the four-stage planetary gear transmission system, and the vibration of the ring gear of the second stage and output shaft are tested with 50%, 75%, 100% and 120% of equivalent load. The experiment results verify the correctness of the theoretical dynamic model of the multistage planetary gear transmission system.