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. 09, 1996
Filed:
Mar. 04, 1994
Louis G Pace, Santa Clara, CA (US);
Thomas A Tacklind, San Martin, CA (US);
Quantum Corporation, Milpitas, CA (US);
Abstract
A low cost, polyphase spindle motor for a hard disk drive comprises a base, a cup-shaped rotating hub for mounting at least one rotating data storage disk, a bearing assembly mounted between the base and the hub enabling rotation of the hub relative to the base, and a cylindrical permanent magnet mounted to an inside cylindrical wall of the hub and defining a plurality of circumferentially alternating magnetic poles. A single ferromagnetic sleeve is mounted to the base and forms one element of the bearing assembly. The sleeve defines a plurality of generally U-shaped stator armature assemblies fixed with respect to the base, each stator armature assembly comprising a top stator disk of ferromagnetic material, a bottom stator disk of ferromagnetic material and a cylindrical portion of the ferromagnetic sleeve magnetically coupling the top disk portion and the bottom disk portion, the stator armature further including a coil between the top stator disk and the bottom stator disk, each stator disk defining a plurality of circumferentially spaced apart stator pole ends being in number related to the number of poles of the permanent magnet, the pole ends of the bottom stator disk being angularly displaced from the pole ends of the top stator disk by a predetermined first electrical angle, the pole ends of the stator disks of each of the plurality of armature assemblies being electrically angularly displaced from the pole ends of at least one of the stator disks of the other of the plurality of armature assemblies by a predetermined second electrical angle.