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:
Aug. 17, 1993
Filed:
Mar. 11, 1991
Tomoo Ueda, Suwa, JP;
Osamu Miyazawa, Suwa, JP;
Joji Kitahara, Suwa, JP;
Tsuneaki Furukawa, Suwa, JP;
Seiko Epson Corporation, Tokyo, JP;
Abstract
An ultrasonic motor comprising a rotor and a stator driven by a piezoelectric element is disclosed. The rotor includes a plurality of gaps which correspond to periods in which piezoelectric sub-element rows are formed. A plurality of level differences on the surface of the stator have rotational symmetry in prescribed periods. Standing waves generated on the stator exert stress on the level differences of non-contact areas of the rotor so as to provide for rotor rest at a relative position where the stress becomes balanced. Stepping operation of the rotor is achieved by movement of the standing waves employing a plurality of level differences with rotational symmetry. The positions where the stress becomes balanced always occur at the same interval thereby facilitating precise stepping operation.