The invention discloses a novel planetary speed
reducer and a
speed reduction motor. The planetary speed
reducer comprises a planetary wheel frame 2, a fixed ring gear 4, a moving ring gear 5, a
coupling plate 6, an output shaft 7, a shell 9, an end cover 8 and an input shaft 11, wherein the planetary wheel frame 2 is fixed on the input shaft 11 and is provided with at least one planetary gear 3; the fixed ring gear 4 is fixed on the end cover 8; the moving ring gear 5 is fixed on the
coupling plate 6; the output shaft 7 is fixed on the
coupling plate 6; the shell 9 is positioned on the output shaft 7 through a bearing; the end cover 8 is positioned on the input shaft 11 through a bearing; the shell 9 and the end cover 8 are fastened tightly; the fixed ring gear 4 and the input shaft 11 are coaxial; the moving ring gear 5 and the output shaft 7 are coaxial; the fixed ring gear 4 and the moving ring gear 5 are same in size and different in gear quantity; and the fixed ring gear 4 and the moving ring gear 5 are parallel and coaxial, are meshed with at least one planetary gear 3 to form a novel planetary
differential transmission mechanism. According to the invention, high-efficiency large speed ratio transmission can be realized, the structure is simple, the cost is low, and the application range is wide.