ULTRASONIC MOTOR

PURPOSE:To obtain a highly efficient and small size ultrasonic motor without changing the fundamental construction of the motor by a method wherein at least the effective part of a piezoelectric device where electrode patterns are provided is formed into an annular shape having a certain width from the outer circumference and the rigidity of the part of a vibrating unit inside the annular part is smaller than the rigidity of the annular part of the vibrating unit. CONSTITUTION:A vibrating unit 1 has a disc-shape and the thickness T1 of its annular circumferential part is larger than the thickness T2 of its inner part. A plurality of protrusions 1a are formed on the annular circumferential part. A piezoelectric device 2 has approximately the same shape as the annular thick part of the vibrating unit 1 and attached to the surface of the annular part opposite to the surface on which the protrusions 1a are provided by bonding, etc. The vibrating unit 1 is unified with a center shaft 4 which is planted in a support plate 3 by pushing the center shaft 4 into the center part of the vibrating unit 1. A moving unit 5 is supported by the center shaft 4 with the center shaft 4 as the center of rotation and pressed against the top parts of the protrusions 1a of the vibrating unit 1 by a pressing spring 6. Lead wires 7 are bonded to the electrode patterns of the piezoelectric device by soldering, etc.