Low cost permanent magnet disk spindle motor
First Claim
1. A low cost, polyphase spindle motor for a disk drive comprising:
- a base,a cup-shaped rotating hub for mounting at least one rotating data storage disk,bearing means mounted between the base and the hub for enabling rotation of the hub relative to the base,a cylindrical permanent magnet mounted to an inside cylindrical wall of the hub and defining eight circumferentially alternating magnetic pole faces,a stator structure mounted to the base and defining a cylindrical ferromagnetic sleeve portion extending from the base and forming one element of the bearing assembly, the sleeve portion defining a pair of stacked, generally U-shaped stator armature portions fixed with respect to the base, each stator armature portion comprising a top stator disk portion of ferromagnetic material, a bottom stator disk portion of ferromagnetic material and wherein the ferromagnetic sleeve portion of the stator structure portion magnetically couples the top stator disk portion and the bottom stator disk portion of each stator armature portion, the stator armature portion further including a coil of conductive wire between the top stator portion and the bottom stator portion, each stator portion 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 portion being angularly displaced from the pole ends of the top stator portion by a first electrical angle of 45 degrees, the pole ends of the stator portions of each of the plurality of stator armature portions being electrically angularly displaced from the pole ends of at least one of the stator portions of the other of the plurality of stator armature portions by a second electrical angle of 22.5 degrees.
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0 Petitions
Accused Products
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.
51 Citations
27 Claims
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1. A low cost, polyphase spindle motor for a disk drive comprising:
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a base, a cup-shaped rotating hub for mounting at least one rotating data storage disk, bearing means mounted between the base and the hub for enabling rotation of the hub relative to the base, a cylindrical permanent magnet mounted to an inside cylindrical wall of the hub and defining eight circumferentially alternating magnetic pole faces, a stator structure mounted to the base and defining a cylindrical ferromagnetic sleeve portion extending from the base and forming one element of the bearing assembly, the sleeve portion defining a pair of stacked, generally U-shaped stator armature portions fixed with respect to the base, each stator armature portion comprising a top stator disk portion of ferromagnetic material, a bottom stator disk portion of ferromagnetic material and wherein the ferromagnetic sleeve portion of the stator structure portion magnetically couples the top stator disk portion and the bottom stator disk portion of each stator armature portion, the stator armature portion further including a coil of conductive wire between the top stator portion and the bottom stator portion, each stator portion 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 portion being angularly displaced from the pole ends of the top stator portion by a first electrical angle of 45 degrees, the pole ends of the stator portions of each of the plurality of stator armature portions being electrically angularly displaced from the pole ends of at least one of the stator portions of the other of the plurality of stator armature portions by a second electrical angle of 22.5 degrees. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A low cost, polyphase spindle motor for a disk drive comprising:
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a base, a cup-shaped rotating hub for receiving and rotating at least one data storage disk, bearing means mounted between the base and the hub for enabling rotation of the hub relative to the base, a cylindrical permanent magnet mounted to an inside cylindrical wall of the hub and defining eight circumferentially alternating magnetic pole faces, a stator structure mounted to the base and defining a cylindrical ferromagnetic sleeve portion extending from the base and forming one element of the bearing assembly, the sleeve portion defining three stacked, generally U-shaped stator armature portions fixed with respect to the base, each stator armature portion comprising a top stator disk portion of ferromagnetic material, a bottom stator disk portion of ferromagnetic material and wherein the ferromagnetic sleeve portion of the stator structure portion magnetically couples the top stator disk portion and the bottom stator disk portion of each stator armature portion, each stator armature portion further including a coil of conductive wire between the top stator portion and the bottom stator portion, each stator portion 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 portion being angularly displaced from the pole ends of the top stator portion by a first electrical angle of 45 degrees, and the pole ends of the stator portions of each of the plurality of stator armature portions being electrically angularly displaced from the pole ends of at least one of the stator portions of the other of the plurality of stator armature portions by a second electrical angle of 60 degrees. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A low cost, polyphase spindle motor for a disk drive comprising:
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a base, a cup-shaped rotating hub for receiving and rotating at least one data storage disk, bearing means mounted between the base and the hub for enabling rotation of the hub relative to the base, a cylindrical permanent magnet mounted to an inside cylindrical wall of the hub and defining eight circumferentially alternating magnetic pole faces, a stator structure mounted to the base and defining a cylindrical ferromagnetic sleeve portion extending from the base and forming one element of the bearing assembly, the sleeve portion defining three stacked, generally U-shaped stator armature portions and four stator disk portions of ferromagnetic material, each stator armature portion including a top stator disk portion, a coil of conductive wire, and a bottom stator disk portion and wherein the ferromagnetic sleeve portion of the stator structure portion magnetically couples the top and bottom stator disk portions, and at least two of the stator disk portions operating magnetically in common with adjacent stator armature portions. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27)
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Specification