Patent ID: 8531084
Filing Date: 2013-09-10
Classification: H02N

Abstract:
1. An ultrasonic motor unit comprising: a piezoelectric element which is provided with a plurality of piezoelectric active regions and has a rectangular cross-sectional shape, and in which longitudinal vibration and bending vibration are excited by applying a predetermined alternating signal to the plurality of piezoelectric active regions to excite elliptic vibration in opposite end faces by combining the vibrations; a holder member which holds the piezoelectric element so as to cover an outer surface of a portion of the piezoelectric element which corresponds to a common node of the longitudinal vibration and the bending vibration; a pressing member which applies a predetermined pressing force to the piezoelectric element through the holder member; a pressing auxiliary member which transfers a pressing force generated by the pressing member to the holder member; a driven member which is in contact with one of the opposite end faces of the piezoelectric element and driven by elliptic vibration of the piezoelectric element; an ultrasonic motor accommodation member which accommodates the piezoelectric element, the holder member, the pressing member, and at least one portion of the driven member; and a power extraction member to which a portion of the driven member accommodated in the ultrasonic motor accommodation member is fixed, and which is coupled to the ultrasonic motor accommodation member to form a joint portion which displaces when the driven member is driven, wherein the ultrasonic motor unit is formed by connecting a plurality of sections each formed by coupling the ultrasonic motor accommodation member to the power extraction member.