Slim spindle motor and micro-drive apparatus comprising the same

Abstract

A slim spindle motor and a micro-drive apparatus including the slim spindle motor are provided. In the spindle motor, a hub is rotatably mounted on a base plate by ball bearings. The hub is used to seat a disk thereon. A ring-shaped magnet is engaged to the outer boundary of the hub. A stator is formed by arranging a plurality of yokes in a round shape around the outer boundary of the ring-shaped magnet. The yokes include cores having curved ends to reduce the central axis offset between the yokes and the ring-shaped magnet. Most of the yokes include coils that cover the cores. Since the central axes of the yokes in the stator are made collinear with the central axis of the ring-shaped magnet, the slim spindle motor can operate stably.

1 - 6 . (canceled)  
   
   
       7 . A spindle motor comprising: 
 a hub seating a disk thereon and rotatably mounted on a base plate by ball bearings;    a ring-shaped magnet engaged to the outer boundary of the hub and having an increased diameter; and    a stator formed by arranging a plurality of yokes in a round shape around the outer boundary of the ring-shaped magnet, wherein the yokes include cores with increased diameters arranged such as to reduced the central axis offset between the yokes and the ring-shaped magnet and most of the yokes include coils that cover the cores.    
   
   
       8 . The spindle motor of  claim 7 , wherein the magnet has a thickness of 1 mm or less.  
   
   
       9 . The spindle motor of  claim 7 , wherein the cores have thickness of 0.5 mm or less.  
   
   
       10 . The spindle motor of  claim 7 , wherein the number of cores is less than the number of poles of the magnet.  
   
   
       11 . The spindle motor of  claim 7 , further comprising: 
 a damper installed on the hub to firmly clamp the disk to the hub; and    a screw locked in the hub to fix the damper to the hub.    
   
   
       12 - 22 . (canceled)  
   
   
       23 . A micro-drive apparatus comprising: 
 a base plate;    a spindle motor including a hub seating a disk thereon and rotatably mounted on a base plate by ball bearings, a ring-shaped magnet engaged to the outer boundary of the hub and having an increased diameter, and a stator formed by arranging a plurality of yokes in a round shape around the outer boundary of the ring-shaped magnet, wherein the yokes include cores with increased diameters arranged such as to reduce the central axis offset between the yokes and the ring-shaped magnet and most of the yokes include coils that cover the cores; and    an actuator including a head, which moves over the disk to write/read data to/from the disk, and a suspension positioned at an end of the head.    
   
   
       24 . The micro-drive apparatus of  claim 23 , wherein the magnet has a thickness of 1 mm or less.  
   
   
       25 . The micro-drive apparatus of  claim 23 , wherein the cores have thickness of 0.5 mm or less.  
   
   
       26 . The micro-drive apparatus of  claim 23 , wherein the number of cores is less than the number of poles of the magnet.  
   
   
       27 . The micro-drive apparatus of  claim 23 , further comprising: 
 a damper installed on the hub to firmly claim the disk to the hub; and    a screw locked in the hub to fix the damper to the hub.    
   
   
       28 - 32 . (canceled)