The gear transmission structure composed of four stage reduction system is selected as the test object, and the gear transmission structure diagram shown in the figure is obtained. When the planetary gear keeps the low speed transmission state, the transmission shaft will become the output part, which not only needs to bear the torque generated by the input shaft, but also needs to bear the torque generated by the load. When the structure of the transmission shaft is deformed, it will interfere with the meshing process of other internal parts and cause the operation failure of the gearbox.
According to the above analysis, in order to deeply understand the vibration state of the system and prevent resonance, this paper focuses on the modal change and vibration mode characteristics of the transmission shaft, and confirms whether the abnormal transmission phenomenon of planetary gear will occur due to resonance.
The qt500 transmission shaft is selected for testing, and the output part of the transmission shaft is supported by the bearing. The cylindrical support and displacement constraints are set respectively.