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. 15, 2003
Filed:
May. 01, 2001
Other;
Abstract
The present invention relates to a vibration wave motor which is configured to prevent abnormal noise from being produced at a start time or a stop time and, more particularly, to a control device for a vibration wave motor which obtains a driving force by applying a periodic voltage to an electro-mechanical energy conversion element so as to generate in a vibration member thereof a plurality of standing waves having a phase difference therebetween, the plurality of standing waves being synthesized to generate a driving vibration in the vibration member. The control device comprises a frequency control circuit which varies a frequency of the periodic voltage and, when a driving force of the vibration wave motor is to be stopped, varies the periodic voltage so as to achieve a predetermined frequency at which a rotational speed of the vibration wave motor becomes zero, and a voltage control circuit which gradually lowers a voltage level of the periodic voltage to a predetermined voltage and then, after the frequency control circuit varies the frequency so as to achieve the predetermined frequency, stops energization of the vibration wave motor.