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:
Apr. 04, 2006
Filed:
Nov. 24, 2004
Kunio Miyashita, Minamiazumi-gun, JP;
Junji Koyama, Minamiazumi-gun, JP;
Muneo Mitamura, Minamiazumi-gun, JP;
Kunio Miyashita, Minamiazumi-gun, JP;
Junji Koyama, Minamiazumi-gun, JP;
Muneo Mitamura, Minamiazumi-gun, JP;
Harmonic Drive Systems Inc., Tokyo, JP;
Abstract
The encoder rotor of an absolute magnetic encoder mounted on a servomotor shaft has a first drum of a bipolar magnet, and a second drum with a Q-bit multipolar magnetic pole track and a reference track. A signal processor generates absolute signals on the basis of detected signals, which differ in phase by 90° and in which a single rotation represents a single period, from X-phase and Y-phase magnetic sensors disposed facing the first drum, and on the basis of A- and B-phase signals, which differ in phase by 90°, and a reference signal obtained from A-, B-, and Z-phase magnetic sensors disposed facing the second drum. Even if the number of bits Q of the multipolar magnetic pole track is increased in order to enhance the resolution, the number of magnetic pole tracks does not need to be increased, and higher resolution can therefore be obtained without increasing the axial length.