Planetary reducer

The invention relates to a planetary reducer. The problems that in an existing planetary reducer, the inner gear locating precision is not high, load non-uniform distribution between planetary gears is prone to being caused, and consequently the reducer is damaged are solved. The planetary reducer comprises a flange plate, a shell, a transmission gear, an output shaft gear, an inner gear and a planetary gear assembly. Planetary gears in the planetary gear assembly are engaged with the inner gear. The inner gear is of an independent gear ring structure. The flange plate and the shell are directly and fixedly connected through a bolt. The inner gear is mounted in the shell. The inner wall face of the shell is provided with a cylindrical inner gear mounting face in clearance fit with the outer cylinder face of the inner gear. Multiple axial round pin holes distributed at intervals in the center circumferential direction are formed in the cooperation position of the outer cylinder face ofthe inner gear and the inner gear mounting face. Cylinder pins in clearance fit are mounted in the round pin holes. In the planetary reducer, when planetary gear loading is non-uniform, the inner gearand planetary gear carriers automatically float till loads between the planetary gears are distributed uniformly, and the reliability of the planetary reducer is effectively improved.