Speed reducer and robot with same

The invention discloses a speed reducer and a robot with the same. The speed reducer comprises an outer shell; an output flange; a gear ring, first outer teeth and second inner teeth; a first harmonic steel gear; a second harmonic rigid gear; an eccentric shaft; the sun gear is tightly arranged on the input shaft section in a sleeving manner; the motor mounting shell is fixedly connected with the outer shell, a motor is arranged on the motor mounting shell, an output shaft of the motor is coaxially provided with a driving gear, the driving gear is meshed with the central gear, and the axis of the output shaft of the motor is parallel to the axis of the input shaft section and does not coincide with the axis of the input shaft section; the whole motor is located on the outer side of the eccentric shaft. The speed reducer is a hollow speed reducer, the speed reduction stage number is two, and the motor mounting position is changed into parallel shaft mounting from coaxial mounting; the hollow cavity of the ecce