The diagnostic analysis of the planet bearing distributed fault using the instantaneous angular speed

The main purpose of this article is to study the planet bearing distributed faults in a planetary gear system using the instantaneous angular speed and their vibration of the corresponding characteristics in the vibration spectrum are synthesized. Distributed bearing faults usually to produce a more intricate vibration spectrum compared with the local failure of bearings. In addition, the planetary bearing rotates not only around the planetary gear shaft, but also around the sun gear shaft. This kind of rotating mechanism brings challenges to the condition monitoring of planetary bearings due to the change of vibration transmission path. To further the understanding of the distributed faults excitation mechanism in a planet bearing, taking planetary bearings as the research object, a 34 DOF planetary gear model including a detailed model of planet bearing was build, and the dynamic response of planet bearing when faults are distributed is obtained. The instantaneous angular velocity (IAS) that measured from the carrier arm is used to analyze the vibration result because of the IAS signal can be easily sampled in the angular domain and shows stronger response to various kinds of flaws in the machine on orders with large bandwidth. A planet bearing fault diagnostic procedure has been developed to improve fault pulse in the vibration signal of planetary bearing, the corresponding amplitude demodulation results have been investigated and analyzed. From the results, it shows that IAS is an alternative promising tool for bearing fault analysis.