Patent ID: 6265800
Filing Date: 2001-07-24
Classification: G11B,H02K

Abstract:
A diskette comprising:a diskette case;a hub rotatable mounted in the diskette case; anda permanent magnet generator provided in the diskette case, for converting mechanical energy into electrical energy while the hub is being positively driven to rotate, the permanent magnet generator having(1) a a ring-shaped permanent magnet provided on the hub and rotatable with the hub, the permanent magnet having a circumferential surface on which a plurality of rotor magnetic poles are arranged, the rotor magnetic poles having alternately different polarities in a circumferential direction, and(2) a stator mounted in the diskette case and extending around the permanent magnet, the stator having a plurality of magnetic pole teeth made of soft magnetic material, the magnetic pole teeth(I) having radially inner ends on which stator magnetic poles are respectively provided, the stator magnetic poles facing the rotor magnetic poles via a magnetic gap,(II) extending radially outward from the stator magnetic poles and having respective stator coils wound thereon, and(III) having radially outer ends that are connected together by a back yoke made of soft magnetic material,the stator having at least one soft magnetic piece positioned between adjacent magnetic pole teeth, the soft magnetic piece having a circumferential width that is equal to or greater than a circumferential width of one of the rotor magnetic poles,wherein an axial thickness of the stator magnetic poles is smaller than an axial thickness of the permanent magnet.