a motor has at least a vibration rod parallel to the axis of a rotor , in which the vibration rod causes a rotary motion in the rotor . the motor is free from the annular stator showing a large attenuation of vibration and is not associated with the stator support . the motor is also provided with a higher efficiency of energy utilization in comparison with a conventional ultrasonic motor , and is free from the stopping or irregular rotation of the rotor . the vibration rod for rotating the rotor requires a smaller space in comparison with the annular stator in the conventional ultrasonic motor .