The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 19, 1992
Filed:
Dec. 03, 1990
Osamu Myohga, Tokyo, JP;
Tadao Uchikawa, Tokyo, JP;
NEC Corporation, , JP;
Abstract
An ultrasonic motor comprises a stator which generates a combined ultrasonic elliptic vibration which is a combined vibration of longitudinal and torsional vibrations, and a rotor which is in press-contact with the stator and driven by the ultrasonic elliptic vibration via a friction force between the rotor and the stator. The stator comprises a first piezoelectric element for generating the longitudinal vibration, a second piezoelectric element for generating the reacting vibration, a headmass having a large stiffness against said longitudinal vibration and a large inertial mass against the torsional vibration, and a rearmass. In the ultrasonic motor, the resonance frequencies of the longitudinal and torsional vibrations are equal, so that the ultrasonic elliptic vibration is generated efficiently on the rotor in a high power state which is adapted in practical use.