Abstract: Focused on the bonding of the piezoelectric ceramic of traveling wave type ultrasonic motors (TWUSM), the effects of the material characteristics and the thickness of the adhesive layer on the vibrating performances of the stator are studied based on the electromechanical coupling finite element model of the stator, and the resisting-shear and vibrating performances of the adhesive layer under different excitating conditions are detailedly analyzed. The methods of improving the bonding quality of the piezoelectric ceramic are presented, and the bonding process and the optimum design of the TWUSM stator are determined at last. It is shown that the thickness of the adhesive layer has little effect on the stator frequency, but great effect on the stator vibration characteristics, and on the premise of enough bond strength, reducing the thickness of the adhesive layer can improve the performance of the TWUSM. Based on the bonding process and optimum design, the 80 mm TWUSM prototype has a good performance that the maximum torque is 1.2 N·m and the no-load rotational speed is 80 r/min.The researching results contribute to the industrialization of USM.

Key words: Adhesive layer, Finite element model, Traveling wave ultrasonic motor(TWUSM), Vibration performances