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:
Aug. 03, 1993
Filed:
Feb. 09, 1990
Hideho Maeda, Kanagawa, JP;
Masanori Kitamura, Tokyo, JP;
Sony Corporation, Kitashinagawa, JP;
Abstract
In a revolution detector of a drive motor of a disk drive, the rotor of the drive motor comprises a shell and a rotary magnet which is secured to the shell. A plurality of through holes of the detector, in which the rotary magnet is partially exposed, are provided at predetermined intervals in such positions of the shell as to give no influence to the magnetic circuit from which the output of the drive motor is derived, and the revolution characteristic of the drive motor is obtained by means of detecting the holes by a sensor in the detector, so that it becomes easier to manufacture the detector, and it is possible to detect the revolution of the drive motor with high accuracy without lowering the efficiency of the drive motor.