Research on the effect of tooth root defects on the motor-multistage gear transmission system

In this paper, a coupled dynamic model is proposed for a motor and a multistage gears system of a coal mining machine with tooth root defects. The model effectively simulates the influence of the tooth root cracks on the vibration signals in a multistage gears system when the cracks occur in the planetary subsystem and fixed-shaft gear train subsystem. Comparing the Kurtosis and Crest factor indicators of planetary gear dynamic force and vibration velocity signals, the former is more sensitive to tooth root faults and more suitable as a dynamic indicator for evaluating the effect of tooth root defects on the planetary gear system. The electromechanical system is simulated by coupling the dynamic model of three-phase asynchronous motor and gear system, and the effect of gear tooth faults with different crack depths on the dynamic characteristics of motor-multistage gear system is explored. The results show that the motor current signature analysis (MCSA) can be applied to the detection of gear tooth faults in the transmission system. This method greatly reduces the workload of signal acquisition and spectrum analysis, and can be used as an effective supplement to the traditional vibration signal detection technology.