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:
Jul. 24, 2001
Filed:
Sep. 07, 1999
Hiroaki Fujii, Echi-gun, JP;
Ryuji Yano, Echi-gun, JP;
Hitoshi Fujita, Echi-gun, JP;
Kenji Kitazawa, Echi-gun, JP;
Takata Corporation, Tokyo, JP;
Abstract
A drive circuit for an ultrasonic motor includes a DC power source, a transformer for applying to the ultrasonic motor two phase high frequency voltage alternating currents having a predetermined phase difference for driving the ultrasonic motor, a switching device interposed between the DC power source and the transformer for allowing a direct current from the direct DC power source to flow to the transformer at a predetermined timing, and a CPU connected to the switching device for controlling the switching device at the predetermined timing. Thus, the alternating current having an optimum frequency can be reliably and easily obtained. The drive circuit may include a vibration attenuating device operated when the ultrasonic motor is stopped. As a result, vibration of a stator of the ultrasonic motor is gradually reduced.