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. 09, 2002
Filed:
Apr. 23, 1997
Izumi Komatsu, Nagano, JP;
Hirohiko Katsuno, Nagano, JP;
Sankyo Seiki Mfg. Co., Ltd., Nagano-ken, JP;
Abstract
A motor comprises a rotor having an index signal generating portion on a rotor magnet and a magnetic resistance sensor having a magneto-sensitive surface. The sensor is positioned on a stator of the motor facing the index signal generating portion of the rotor with a predetermined gap. The sensor functions to sense an index signal in the magnetic field generated by the index signal generating portion during the rotation of the rotor. A speed detection circuit is included for detecting the speed of the motor based on the detection results of the magnetic resistance sensor. The index generating portion forms a magnetic area in which a magnetic flux intensity in a plane orthogonal to the principal magnetic flux of the index signal generating portion is greater than the rated sensitivity of the magnetic resistance sensor. The magnetic resistance sensor is positioned on the magnetized area such that its magneto-sensitive surface is parallel to the plane. The magnetic resistance sensor has an output which is in a saturated state.