The structural characteristics of the planetary gear reducer are as follows: the planetary gear bearing is installed in the planetary gear, and the planetary shaft is fixed in the planetary shaft hole of the planetary gear frame; The output shaft is connected with the planetary frame through the key, the support bearing is located in the reducer casing, the solar gear is connected with the high-speed shaft through the double-gear coupling, so as to realize the floating of the solar gear. The floating principle of the sun wheel is shown in Figure 3-1.