Contact Mechanics of Traveling Wave Ultrasonic Motors

In the pursuit of high areal recording density towards 10 Tb/in $^{2}$ , it is necessary to improve the positioning accuracy of the magnetic head in the hard disk drive head-positioning control system. Ultrasonic motors are novel electric motors well used in positioning control. Contact stresses can exist in the friction material and rotor. Obtaining the details of the stress distribution due to the inelastic deformation is important. A contact model of traveling wave ultrasonic motor (TWUSM) is proposed. A 2-D finite element model between stator and friction material is then developed. The evolution of deformation in friction material and rotor due to the mechanical surface loading is presented.