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. 15, 1990
Filed:
May. 03, 1989
Etsuro Furutsu, Kawasaki, JP;
Kazuhiro Izukawa, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Disclosed is a driving apparatus for a vibration wave motor in which monitor means is provided for detecting the vibrating state of the vibration wave motor and the difference between the resonance frequency and the frequency of a driving AC signal is detected on the basis of the phase difference between the output signal from the monitor means and the driving AC signal and when the frequency difference is great during the change of the number of revolutions of the motor, the vibration rate of the frequency of the driving AC signal is made greater to improve the responsiveness while, on the other hand, when the frequency difference is small, the variation rate of the frequency of the driving AC signal is made smaller to thereby prevent the occurrence of an unstable operation in which the frequency of the driving AC signal exceeds the resonance frequency to cause sudden stoppage of the motor.