Development of a new type piezoelectric micromotor

Abstract

To realize miniaturization of actuators, construction of the actuators necessitates simple structured components and easy configuration. To satisfy these requirements, we devised a piezoelectric micromotor with a simplified and flat stator [K. Tani, M. Suzuki, K. Furuta, T. Sakuhara, T. Ataka, Development of a new type piezoelectric micromotor, Proc. 11th IEEE Ann. Int. Workshop on Micro Electro Mechanical Systems (MEMS '98), Heidelberg, Germany, Jan 25–29, 1998, pp. 396–401]. This former micromotor is 2 mm both in diameter and in height, and generates rotation by micro vibration of the stator. For the former micromotor, we have experimentally confirmed that the rotational characteristics correlated with the contact condition between the rotor and the stator, and that the condition was essential to stable rotational characteristics. Therefore, we have devised a new type piezoelectric micromotor with a flat spring that adjusts contact conditions, which structure is suited for further miniaturization. The new micromotor is 2 mm in diameter, 0.3 mm in height and the volume is 0.49 mm 3 (which is one seventh of that of the former micromotor). The new micromotor stably rotates at any posture, and the starting torque is measured at about 3.2 μNm. The new type piezoelectric micromotor consists of components whose structure functions flexibly such as the Smart structure, which is different from the conventional actuators. In this study, we have achieved a micro-sized motor for practical use in micro-mechanism fields.