US Patent 11772260 Planetary gear transmission device and robot having the same

A planetary gear transmission device is provided including a planetary gear device including a sun gear, a ring gear, a plurality of planet gears, and a carrier, a motor to generate a rotational force input to the planetary gear device and including a motor shaft and a motor body, a fixing bracket formed to fix one of the sun gear, the ring gear, or the carrier of the planetary gear device to prevent rotation, and a recursive rotation bracket provided with the motor and fixed to one of the parts of the planetary gear device, which is not fixed by the fixing bracket, wherein when one of the parts of the planetary gear device connected to the motor shaft is rotated by the motor shaft, the motor body is rotated by the recursive rotation bracket and the rotational force of the motor shaft is output through the recursive rotation bracket.