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:
Mar. 27, 2007
Filed:
Nov. 22, 2004
Kunio Miyashita, Nagano-ken, JP;
Junji Koyama, Nagano-ken, JP;
Kunio Miyashita, Nagano-ken, JP;
Junji Koyama, Nagano-ken, JP;
Harmonic Drive Systems Inc., Tokyo, JP;
Abstract
An encoder mounted on a motor axle of an AC servomotor has a single bipolarly magnetized rotational disk, magnetic sensors for outputting X- and Y-signals that differ in phase by 90° in association with the rotation thereof, and a signal processing unit. The signal processing unit computes at predetermined cycles a rotor angle θa of a motor rotor on the basis of the X- and Y-phase signals, generates three-phase magnetic pole signals U, V, and W that differ in phase by 120° on the basis of the number M of magnetic poles of a motor, a magnetic pole reference angle θo, and the rotor angle θa; and generates A- and B-phase signals with predetermined pulse cycles that differ in phase by 90° on the basis of the rotor angle θa. An encoder that is advantageous for reducing the size and weight of an AC servomotor can be realized because it is sufficient to provide a single assembly composed of a rotational disk and magnetic sensors.