The invention discloses a planetary 
reducer applied to a ring 
rolling mill. The planetary 
reducer comprises an input 
bevel gear shaft, a 
bevel gear, a crowned gear shaft, a connecting inner gear sleeve, a sun gear, a 
planet gear, an inner gear ring, a 
planet carrier and a 
machine body, the input 
bevel gear shaft is installed on a bearing sleeve through a sliding bearing, the bearing sleeve is installed on the 
machine body, the bevel gear is fixed to the crowned gear shaft through a key, the two ends of the crowned gear shaft are installed on a lower support and the 
machine body through bearings, the sun gear and the crowned gear shaft are connected through the connecting inner gear sleeve, the 
planet gear is installed on the planet carrier through the bearing and the planet gear shaft, the inner gear ring is fixed to the machine body through a pin, the planet carrier is installed on the upper support through the bearing, and the planetary 
reducer of the ring rolling machine is integrally formed; power is transmitted to the sun gear from the input bevel gear shaft through the bevel gear and the crowned gear shaft, then transmitted to the planet gear from the sun gear and then transmitted to the planet carrier from the planet gear, and 
power output is achieved. The planetary reducer applied to the ring 
rolling mill is reasonable in structure, relatively low in cost, convenient to install, use and maintain, reliable in performance and low in investment.