Hard disk drive device

Abstract

The object of tho present invention is to provide a hard disk drive device having a bearing means of larger size and sufficient strength, improved impact resistance, high accuracy of rotation, and high reliabililty In accordance with the present invention, a hard disk drive device is provided with a motor including; a rotor or hub having around outer periphery thereof a downwardly depending flange, said hub is journalled rotatablly on a base by means of a bearing means, maid hub is provided with a magnet on the inner peripheral surface of the downwardly depending flange, the hub is also provided with an inner shoulder on the top thereof; and a stator provided on the base so as to opposed face to face with said magnet, said stator includes coils: and a magnetic disk having a central aperture to be fitted around the inner shoulder provided on the hub: wherein the outer diameter of the downwardly depending flange of said hub is larger than the inner diameter of the central aperture of the magnetic disk, the outer diameter of said magnet surrounded by said downwardly depending flange ia larger than the outer diameter of said inner shoulder, the inner diameter of the magnet as well as the outer and inner diameters of the stator are enlarged, and the outer diameter of the bearing means is enlarged.

What is claimed is:  
     
         1 . A hard disk drive device comprising 
 a motor including; 
 a rotor or hub having around outer periphery thereof a downwardly depending flange, said hub is journalled rotatablly on a base by means of a bearing means, said hub is provided with a magnet on the inner peripheral surface of the downwardly depending flange, the hub is also provided with an inner shoulder on the top thereof; and,  
 a stator provided on the base so as to opposed face to face with said magnet, said stator includes coils: and,  
 a magnetic disk having a central aperture to be fitted around the inner shoulder provided on the hub;  
 wherein the outer diameter of the downwardly depending flange of said hub is larger than the inner diameter of the central aperture of the magnetic disk, the outer diameter of said magnet surrounded by said downwardly depending flange is larger than the outer diameter of said inner shoulder, and the inner diameter of the magnet as well as the outer and inner diameters of the stator are enlarged, and the outer diameter of the bearing means is enlarged.  
   
     
     
         2 . The hard disk drive device according to  claim 1 , wherein the bearing means includes an outer race of sleeve form mounted vertically on said base, a stopped shaft having an upper enlarged diameter shaft portion and a lower reduced diameter shaft portion, and an inner race fitted around the reduced diameter portion of the shaft, and upper and lower rows of balls, wherein said outer race is provided on the inner peripheral surface thereof with upper and lower rolling contact grooves, said hub is fixedly secured to the upper end of the shaft, balls of the upper row are interposed between a rolling contact groove formed directly on the outer peripheral surface of the larger diameter portion of said shaft and the upper rolling contact groove of said outer race, and balls of the lower row are interposed between a rolling contact groove formed on the outer peripheral surface of the inner race and the lower rolling contact groove of said outer race.  
     
     
         3 . The hard disk drive device according to  claim 2 , wherein the outer diameter of the larger diameter portion of said shaft and that of the inner race are substantially equal, so that the diameter of the balls of the upper row is substantially equal to that of the balls of the lower row.  
     
     
         4 . The hard disk drive device according to  claim 1 , wherein the bearing means includes an outer race of sleeve form integrally formed with said hub to depend downwardly from the central portion of said hub, a stepped shaft having a lower enlarged diameter shaft portion and an upper reduced diameter shaft portion, and an inner race fitted around the reduced diameter portion of the shaft, and upper and lower rows of balls, wherein said outer race is provided on the inner peripheral surface thereof with upper and lower rolling contact grooves, said shaft is mounted vertically on said base, the balls of the upper row are interposed between a rolling contact groove formed on tho outer peripheral surface of the inner race and the upper rolling contact groove of said outer race, and the balls of the lower row are interposed between a rolling contact groove formed directly onto the outer peripheral surface of the larger diameter portion of said shaft and the lower rolling contact groove of said outer race.  
     
     
         5 . The hard disk drive device according to  claim 4 , wherein the outer diameter of said larger diameter portion of said shaft is substantially equal to that of the inner race, so that the diameter of the balls of the upper and lower rows are substantially identical with each other.  
     
     
         6 . A hard disk drive device comprising 
 a motor including; 
 a rotor or hub having around outer periphery thereof a downwardly depending flange, said hub is journalled a rotatablly on a base by means of a bearing means, said hub is provided with a magnet on the inner peripheral surface of the downwardly depending flange, the hub is also provided with an inner shoulder on the top thereof; and,  
 a stator provided on the base so as to opposed face to face with said magnet, said stator includes coils: and,  
 a magnetic disk having a central aperture to be fitted around the inner shoulder provided on the hub:  
 wherein the outer diameter of the downwardly depending flange of said hub is larger than the inner diameter of the central aperture of the magnetic disk, the outer diameter of said magnet surrounded by said downwardly depending flange is larger than the outer diameter of said inner shoulder, the inner diameter of the magnet as well as the outer and inner diameters of the stator are enlarged, and the outer diameter of the bearing means is enlarged, said hub also includes an outer shoulder larger in its diameter than that of the inner shoulder and smaller than that of the downwardly depending flange to form a clearance allowing the access of the magnetic head into the space defined between the downwardly depending flange and the magnetic disk.  
   
     
     
         7 . The hard disk drive device according to  claim 6 , wherein the bearing means includes an outer race of sleeve form mounted vertically on said base, a stepped shaft having an upper enlarged diameter shaft portion and a lower reduced diameter shaft portion, and an inner race fitted around the reduced diameter portion of the shaft, and upper and lower rows of balls, wherein said outer race is provided on the inner peripheral surface thereof with upper and lower rolling contact grooves, said hub is fixedly secured to the upper end of the shaft, balls of the upper row are interposed between a rolling contact groove formed directly on the outer peripheral surface of the larger diameter portion of said shaft and the upper rolling contact groove of said outer race, and balls of the lower row are interposed between a rolling contact groove formed on the outer peripheral surface of the inner race and the lower rolling contact groove of said outer race.  
     
     
         8 . The hard disk drive device according to  claim 7 , wherein the outer diameter of the larger diameter portion of said shaft and that of the inner race are substantially equal, so that the diameter of the balls of the upper row is substantially equal to that of the balls of the lower row.  
     
     
         9 . The hard disk drive device according to  claim 6 , wherein the bearing means includes an outer race of sleeve form integrally formed with said hub to depend downwardly from the central portion of said hub, a stepped shaft having a lower enlarged diameter shaft portion and an upper reduced diameter shaft portion, and an inner race fitted around the reduced diameter portion of the shaft, and upper and lower rows of balls, wherein said outer race is provided on the inner peripheral surface thereof with upper and lower rolling contact grooves, said shaft is mounted vertically on said base, the balls of the upper row are interposed between a rolling contact groove formed on the outer peripheral surface of the inner race and the upper rolling contact groove of said outer race, and the balls of the lower row are interposed between a rolling contact groove formed directly onto the outer peripheral surface of the larger diameter portion of said shaft and the lower rolling contact groove of said outer race.  
     
     
         10 . The hard disk drive device according to  claim 9 , wherein the outer diameter of said larger diameter portion of said shaft is substantially equal to that of the inner race, so that the diameter of the balls of the upper and lower rows are substantially identical with each other.