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. 25, 1993
Filed:
Jul. 02, 1991
Masafumi Naito, Kanagawa, JP;
Asmo Co., Ltd., , JP;
Abstract
A device and method are provided for driving an ultrasonic motor. The motor's initial start drive frequency is set higher than the resonant frequency of the motor and an initial target drive frequency is set lower than the resonant frequency. A drive signal is then applied to a piezoelectric element on the stator in order to rotate the rotor. The frequency of the drive signals is then swept from the start frequency to the target frequency. Abnormal vibrations of the rotor that occur during sweeping of the drive frequency are detected by a monitor electrode mounted on the stator. Upon the detection of an abnormal vibration, the target frequency is reset to equal the drive frequency at which the abnormal vibration was detected. The drive frequency is then reset to a reset start frequency that is higher than the reset target frequency. Thereafter, the drive frequency sweeping step is repeated. This provides a high output from the motor without generating noise.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile