POWER TRANSMISSION DEVICE AND AUTOMOBILE INCLUDING THE SAME

Disclosed is a power transmission device including a motor including a rotary shaft, a speed reducer provided on one side of the motor, and a power transmitter, provided inside the speed reducer, that transmits rotational force generated by driving of the motor to the speed reducer. The power transmitter transmits the power such that a ratio of rotational angular velocity of the speed reducer to rotational angular velocity of the rotary shaft is changed according to rotation directions of the rotary shaft of the motor.