Circular-arc triangular tooth-gear difference planetary gear reducer

The invention discloses a circular-arc triangular tooth-gear difference planetary gear reducer. The circular-arc triangular tooth-gear difference planetary gear reducer consists of a circular-arc inner gear ring (1), a circular-arc outer tooth planetary gear (2), a circular-arc inner gear ring (3), a circular-arc outer tooth planetary gear (4), an input shaft (5), pins (6), pin sleeves (7), an output inner gear retainer (8), an output shaft (9), an input end box wall (10), an output end box wall (11), an output end small cover (12), a box body (13), rolling bearings (14), a key (15), bolts (16), an oil plug (17), an oil seal (18) and a rubber sealing ring (19), and is characterized in that the circular-arc inner gear ring (1), the circular-arc outer tooth planetary gear (2), the circular-arc inner gear ring (3) and the circular-arc outer tooth planetary gear (4) are inner and outer gears of two sets of gear difference circular-arc tooth planetary gear transmission pairs respectively and construct a 2Z-X gear