Vibration features and sidebands investigation of a planetary gear transmission system under misaligned bearing and damaged cage

Aiming at the abnormal vibration due to the support-bearing misalignment and cage damage in a planetary gear transmission system (PGTS), a condition monitoring simulation method for bearing damage is proposed. By analyzing the vibration signals of the system, the sideband distribution law of the PGTS under misaligned bearing and damaged cage is found. On this basis, an indicator of the sideband energy ratio is proposed to measure the damage degree of the cage. The mapping relationship between fault modes, degrees, and state indicators is established. It is found that the typical vibration features of the system under the condition of the outer ring misalignment and the inner ring misalignment have significant differences. The proposed indicator can effectively detect the occurrence and severity of the support-bearing failure in the PGTS.