Driving actuator, mechanical limb and robot

The embodiment of the utility model relates to the technical field of robots, in particular to a driving actuator which comprises a shell provided with an opening; the driving motor is located in the shell, the driving motor is provided with a containing space, the driving motor comprises a stator and a rotor which are arranged in an inner and outer sleeving mode, the stator and the rotor both surround the containing space, the stator is fixed to the shell, and the rotor is rotatably arranged on the shell; the transmission device is arranged in the containing space and comprises a power input end, a speed reducer assembly and a power output end, the power input end is in transmission connection with the power output end through the speed reducer assembly, the power input end is fixed to the rotor, and the power output end is exposed out of the opening. The embodiment of the utility model further provides the mechanical limb and the robot. According to the driving actuator, the mechanical limb and the robot pr