For a planetary mechanism, structural design defects, manufacturing and installation errors, lack of stiffness of the support structure and other factors may cause to a certain degree unequal load sharing, thus affecting the life and reliability of the entire body. A reliability prediction model for the planetary gear set is established by using the concept of minimum order statistics, and the model reflects the influence of partial load on the reliability of the planetary gear set. A detailed kinematics and mechanics analysis of the mechanism is carried out, and the random load histories of each gear are calculated. According to the law of Miner linear fatigue cumulative damage, the random load histories are transformed into equivalent constant amplitude load spectrums, which are taken as the load input variable for the reliability model. The fatigue life data of specific gears are then statistically processed, and the treated life information is used as the strength input variable for the reliability model. According to the prediction result of the model, the adverse effects of partial load on the reliability of the planetary gear set are quantitatively explained, and the effectiveness of the model is verified by randomly censored data processing.
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