Calculation of loading torque on sucker rod in surface driving screw pump system;

Experimental study on new type conic section driving ultrasonic motor;

To increase the contact area and obtain more uniform contact stress distribution within contact surface for reducing wear,a non-axisymmetric vibration model of thin shell is adopted to develop a novel cylinder driving ultrasonic motor,and the structure of the novel motor was designed following the driving mechanism of piezoelectric ceramic.