Rank type differential planet reducer

A rank type differential planet reducer comprises a connecting flange, inner gear ring boxes, a rank type planet carrier, a sun gear shaft, a differential planet wheel, planet wheels and the like. At least four planetary gear trains are evenly distributed on the rank type planet carrier along the circumferential direction. At least one planetary gear train is distributed on the rank type planet carrier along the axial direction. Correspondingly, at least four planet wheel shafts, planet wheel bearing parts and the like are evenly distributed on the rank type planet carrier. The planet wheel shafts are arranged on the rank type planet carrier through elastic linings arranged on the rank type planet carrier. The planet wheels are arranged on the rank type planet carrier through bearings and the planet wheel shafts which are arranged in the inner holes of the planet wheels and the linings. The sun wheel shaft is arranged in the rank type planet carrier, and constantly meshed with gear teeth of a planet gear. The gear teeth of the planet gear and inner teeth of an inner gear ring are constantly meshed.