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:
Apr. 03, 2001
Filed:
Dec. 17, 1998
ASMO Co., Ltd., , JP;
Abstract
An ultrasonic motor includes a stator having a piezoelectric element and a rotor facing the stator. The piezoelectric element vibrates the stator to rotate the rotor. A lining member is located between the rotor and the stator. A spring is installed in the motor. The spring is deformed by a predetermined amount to press the rotor against the stator. The force of the spring pressing the rotor changes in accordance with the deformation of the spring. The spring is installed such that its deformation is in a predetermined range, so that, within the range, the urging force of the spring changes by a relatively small amount for a given change of deformation. Therefore, when deformation of the spring changes due to wearing of the lining member, the urging force of the disk spring scarcely changes. Accordingly, the rotation characteristics of the motor scarcely change over time.