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. 08, 2014
Filed:
Mar. 25, 2011
Yoshinori Hayashi, Iwata, JP;
Akihiko Komatsu, Hamamatsu, JP;
Yoshinori Hayashi, Iwata, JP;
Akihiko Komatsu, Hamamatsu, JP;
Yamaha Corporation, , JP;
Abstract
A displacement detecting apparatus of an electromagnetic actuator, including: an electromagnetic actuator including: a movable core; a drive coil which causes a displacement of the movable core; and a detection coil disposed at a position where a mutual coupling coefficient with the drive coil changes with the displacement, the actuator transmitting a drive force of the movable core to a mechanical system; a drive portion for supplying a drive current to the drive coil on the basis of a pulse width modulation signal; and a displacement detecting portion to which an output voltage of the detection coil is inputted, for outputting a displacement detection signal, wherein the displacement detecting portion includes: a sampling-signal generating portion for generating a sampling signal in synchronism with the pulse width modulation signal; and a synchronous sampling portion for outputting the displacement detection signal by sampling the output voltage in synchronism with the sampling signal.