Spindle motor having a fluid dynamic bearing system and a stationary shaft

Abstract

The invention relates to a spindle motor having a fluid dynamic bearing system comprising axial and radial bearings that contains a rotor component ( 14 ) which encloses a stationary shaft ( 12 ), which in turn is connected at both its ends to axially aligned bearing parts ( 16; 18 ) that are fashioned such that they form capillary sealing gaps ( 32; 34 ), a recirculation channel ( 28 ) filled with bearing fluid that connects the remote regions of the bearing to each other, and an electromagnetic drive system ( 42, 44 ) for driving the rotor component.

The invention claimed is: 
     
       1. A spindle motor having a fluid dynamic bearing system comprising:
 a stationary shaft ( 12 ;  212 ;  312 ) that is held directly or indirectly in a baseplate ( 10 ,  210 ;  310 ),   a rotor component ( 14 ,  114 a;  214 ;  314 a-c) rotatably supported with respect to the shaft about a rotational axis ( 46 ;  246 ;  346 ),   a bearing gap ( 20 ,  220 ;  320 ) open at both ends filled with a bearing fluid that separates the adjoining surfaces of the shaft ( 12 ;  212 ;  312 ), the rotor component ( 14 ,  114 a;  214 ;  214 a-c) and at least one first bearing part ( 16 ,  216 ;  316 ) from one another, a first radial bearing ( 22 a,  222 a;  322 a) and a second radial bearing ( 22 b,  222 b;  322 b) formed between the opposing axially extending bearing surfaces of the shaft ( 12 ;  212 ;  312 ) and the rotor component ( 14 ,  114 a;  214 ;  314 a-c),   an axial bearing ( 26 ,  226 ;  326 ) formed between the opposing radially extending bearing surfaces of the rotor component ( 14 ,  114 a;  214 ;  314 a-c) and the first bearing part ( 16 ,  216 ;  316 ) connected to the baseplate,   a recirculation channel ( 28 ;  128 ;  228 ;  328 ) filled with bearing fluid that connects the remote regions of the bearing to each other, and   an electromagnetic drive system ( 42 ,  44 ;  342 ,  244 ) for driving the rotor component, and   characterized in that the recirculation channel ( 28 ,  128 ;  228 ) ends in a gap ( 21 ) radially outside of the bearing gap ( 20 ) of the axial bearing ( 26 ), the width of the gap ( 21 ) being greater than the width of the bearing gap ( 20 ).   
     
     
       2. A spindle motor according to  claim 1 , characterized in that the rotor component consists of an inner, sleeve-shaped rotor component ( 114 a;  314 a) and an outer cup-shaped rotor component ( 144 b;  314 b). 
     
     
       3. A spindle motor according to  claim 2 , characterized in that the inner, sleeve-shaped rotor component ( 314 a) is enclosed by a further, sleeve-shaped rotor component ( 314 c) on which the outer cup-shaped rotor component ( 314 b) is disposed. 
     
     
       4. A spindle motor according to  claim 1 , characterized in that it only contains one rotating, mechanical rotor component ( 14 ;  214 ) taking the form of a hub/bearing bush arrangement. 
     
     
       5. A spindle motor according to  claim 1 , characterized in that the first bearing part ( 216 ) is integrally formed with the shaft ( 212 ) as one piece. 
     
     
       6. A spindle motor according to  claim 1 , characterized in that a second bearing part ( 18 ;  318 ) is integrally formed with the shaft ( 12 ) as one piece. 
     
     
       7. A spindle motor according to  claim 1 , characterized in that the rotor component ( 14 ,  114 a;  214 ;  314 a-c) has surfaces that are fashioned such that, together with surfaces of the second bearing part ( 18 ;  218 ;  318 ), they form a sealing gap ( 32 ;  232 ;  332 ) of a capillary gap seal. 
     
     
       8. A spindle motor according to  claim 1 , characterized in that the rotor component ( 14 ,  114 a;  214 ;  314 a-c) has surfaces that are fashioned such that, together with surfaces of a first bearing part ( 16 ;  216 ;  316 ), they form a sealing gap ( 34 ;  234 ;  334 ) of a capillary gap seal. 
     
     
       9. A spindle motor according to  claim 1 , characterized in that the recirculation channel ( 328 ) is disposed in the rotor component ( 314 a) or between the rotor components ( 314 a,  314 c) and connects the sealing gap ( 334 ) radially outside the axial bearing ( 226 ) to a section of the bearing gap ( 320 ) located radially outside a dynamic pumping seal. 
     
     
       10. A spindle motor according to  claim 1 , characterized in that the recirculation channel ( 28 ,  128 ;  228 ) is disposed at an incline to the rotational axis ( 46 ), which, on rotation of the rotor component, causes a centrifugal force to be exerted on the bearing fluid held in the recirculation channel, the centrifugal force transporting the bearing fluid through the recirculation channel ( 28 ,  128 ;  228 ) in the direction of arrow ( 29 ). 
     
     
       11. A spindle motor according to  claim 10 , characterized in that the recirculation channel ( 28 ,  128 ;  228 ) is inclined at an angle of 5 to 15 degrees with respect to the rotational axis ( 46 ). 
     
     
       12. A spindle motor according to  claim 10 , characterized in that the centrifugal force exerted on the bearing fluid due to the inclined recirculation channel ( 28 ,  128 ;  228 ) acts in the same direction as a pumping force exerted on the bearing fluid due to an overall pumping effect of the axial bearing ( 26 ;  126 ;  226 ;  326 ) and the radial bearings ( 22 a,  22 b;  122 a,  122 b;  222 a,  222 b;  322 a,  322 b). 
     
     
       13. A spindle motor according to  claim 12 , characterized in that the pumping force generated by the centrifugal force is directed to the axial bearing ( 26 ). 
     
     
       14. A spindle motor according to  claim 12 , characterized in that the centrifugal force is at least twice as big as the force exerted on the bearing fluid due to the overall pumping effect of the axial bearing ( 26 ) and the radial bearings ( 22 a,  22 b). 
     
     
       15. A spindle motor according to  claim 1 , characterized in that a dynamic pumping seal ( 36 ;  236 ;  336 ) is formed between opposing radially extending surfaces of the rotor component ( 14 ,  114 ;  214 ;  314 ) and a second bearing part ( 18 ;  218 ;  318 ) connected to the shaft. 
     
     
       16. A spindle motor according to  claim 15 , characterized in that the dynamic pumping seal ( 36 ;  236 ;  336 ) is formed between a radially extending end face of the rotor component ( 14 ,  114 a;  214 ;  314 a) and an adjoining radially extending end face of the second bearing part ( 18 ;  218 ;  318 ). 
     
     
       17. A spindle motor according to  claim 15 , characterized in that the dynamic pumping seal ( 36 ;  236 ;  336 ) is disposed substantially perpendicular and the sealing gap ( 32 ;  232 ;  332 ) of the gap seal substantially parallel to the rotational axis ( 46 ;  246 ;  346 ). 
     
     
       18. A spindle motor according to  claim 1 , characterized in that the baseplate ( 10 ;  310 ) has a ferromagnetic ring ( 40 ;  340 ) that lies axially opposite a rotor magnet ( 44 ;  344 ) of the electromagnetic drive system and is magnetically attracted by this magnet and that they generate a magnetic force that is directed in the opposite direction to a bearing force generated by the axial bearing ( 26 ;  326 ). 
     
     
       19. A spindle motor according to  claim 18 , characterized in that the electromagnetic drive system comprises a stator arrangement ( 42 ;  342 ) which is disposed at an axial offset with respect to the rotor magnet ( 44 ;  344 ) and generate a magnetic force that is directed in the opposite direction to a bearing force generated by the axial bearing ( 26 ;  326 ). 
     
     
       20. A spindle motor according to  claim 1 , characterized in that adjacent surfaces of the second bearing part ( 18 ) and the rotor component  14  form a further axial bearing ( 25 ). 
     
     
       21. A spindle motor according to  claim 1 , characterized in that a further bearing part ( 19 ) connected to the rotor component adjoins the second bearing part ( 18 ), a pumping seal ( 36 ) being disposed between the two bearing parts ( 18 ,  19 ) and a sealing gap being disposed between the bearing part ( 19 ) and the shaft ( 12 ). 
     
     
       22. A spindle motor having a fluid dynamic bearing system comprising:
 a stationary shaft ( 12 ;  212 ;  312 ) that is held directly or indirectly in a baseplate ( 10 ,  210 ;  310 ),   a rotor component ( 14 ,  114 a;  214 ;  314 a-c) rotatably supported with respect to the shaft about a rotational axis ( 46 ;  246 ;  346 ),   a bearing gap ( 20 ,  220 ;  320 ) open at both ends filled with a bearing fluid that separates the adjoining surfaces of the shaft ( 12 ;  212 ;  312 ), the rotor component ( 14 ,  114 a;  214 ;  214 a-c) and at least one first bearing part ( 16 ,  216 ;  316 ) from one another, a first radial bearing ( 22 a,  222 a;  322 a) and a second radial bearing ( 22 b,  222 b;  322 b) formed between the opposing axially extending bearing surfaces of the shaft ( 12 ;  212 ;  312 ) and the rotor component ( 14 ,  114 a;  214 ;  314 a-c),   an axial bearing ( 26 ,  226 ;  326 ) formed between the opposing radially extending bearing surfaces of the rotor component ( 14 ,  114 a;  214 ;  314 a-c) and the first bearing part ( 16 ,  216 ;  316 ) connected to the baseplate,   a recirculation channel ( 28 ;  128 ;  228 ;  328 ) filled with bearing fluid that connects the remote regions of the bearing to each other, and   an electromagnetic drive system ( 42 ,  44 ;  342 ,  244 ) for driving the rotor component,   characterized in that the recirculation channel ( 28 ,  128 ;  228 ) ends in a gap ( 21 ) radially outside of the bearing gap ( 20 ) of the axial bearing ( 26 ), and   further characterized in that the width of the gap ( 21 ) is greater than or equal to the width of the bearing gap ( 20 ) of the axial bearing ( 26 ) plus the depth of the bearing patterns of the axial bearing ( 26 ).   
     
     
       23. A spindle motor having a fluid dynamic bearing system comprising:
 a stationary shaft ( 12 ;  212 ;  312 ) that is held directly or indirectly in a baseplate ( 10 ,  210 ;  310 ),   a rotor component ( 14 ,  114 a;  214 ;  314 a-c) rotatably supported with respect to the shaft about a rotational axis ( 46 ;  246 ;  346 ),   a bearing gap ( 20 ,  220 ;  320 ) open at both ends filled with a bearing fluid that separates the adjoining surfaces of the shaft ( 12 ;  212 ;  312 ), the rotor component ( 14 ,  114 a;  214 ;  214 a-c) and at least one first bearing part ( 16 ,  216 ;  316 ) from one another, a first radial bearing ( 22 a,  222 a;  322 a) and a second radial bearing ( 22 b,  222 b;  322 b) formed between the opposing axially extending bearing surfaces of the shaft ( 12 ;  212 ;  312 ) and the rotor component ( 14 ,  114 a;  214 ;  314 a-c),   an axial bearing ( 26 ,  226 ;  326 ) formed between the opposing radially extending bearing surfaces of the rotor component ( 14 ,  114 a;  214 ;  314 a-c) and the first bearing part ( 16 ,  216 ;  316 ) connected to the baseplate,   a recirculation channel ( 28 ;  128 ;  228 ;  328 ) filled with bearing fluid that connects the remote regions of the bearing to each other, and   an electromagnetic drive system ( 42 ,  44 ;  342 ,  244 ) for driving the rotor component, and   a sealing gap ( 32 ;  332 ) for sealing the bearing gap ( 20 ,  220 ;  320 ) which is covered by an annular cover ( 30 ,  130 ;  330 ) connected to the rotor component ( 14 ;  114 a;  314 c) that, together with the second bearing part ( 18 ;  318 ), forms a labyrinth seal ( 48 ;  348 ).   
     
     
       24. A spindle motor according to  claim 23 , characterized in the annular cover ( 330 ) is formed by the rotor component. 
     
     
       25. A spindle motor according to  claim 23 , characterized in that the sealing gap ( 32 ) is formed between an inner circumferential surface of the cover ( 130 ) and an outer circumferential surface of the second bearing part ( 18 ). 
     
     
       26. A spindle motor according to  claim 23 , characterized in that the sealing gap ( 32 ;  332 ) is formed between an inner circumferential surface/end face of the rotor component ( 14 ,  114 a;  214 ;  314 a;  314 c) and an outer circumferential surface/end face of the second bearing part ( 18 ;  218 ;  318 ). 
     
     
       27. A spindle motor according to  claim 23 , characterized in that the sealing gap ( 34 ;  234 ;  334 ) is formed between an outer circumferential surface of the rotor component ( 14 ,  114 a;  214 ;  314 a;  314 c) and an inner circumferential surface of the first bearing part ( 16 ;  216 ;  316 ). 
     
     
       28. A spindle motor according to  claim 23 , characterized in that surfaces of the rotor component ( 14 ,  144 a;  214 ) or the cover ( 130 ) and the second bearing part ( 18 ;  218 ) forming the sealing gap ( 32 ;  232 ) extend substantially parallel to the rotational axis ( 46 ;  246 ) or are inclined at an acute angle to the rotational axis. 
     
     
       29. A spindle motor according to  claim 23 , characterized in that surfaces of the rotor component ( 14 ,  114 a;  214 ;  314 a;  314 c) and the first bearing part ( 16 ;  216 ;  316 ) forming the sealing gap ( 34 ;  234 ;  334 ) extend substantially parallel to the rotational axis ( 46 ;  246 ;  346 ) or are inclined at an acute angle to the rotational axis. 
     
     
       30. A hard disk drive comprising a spindle motor for rotatably driving at least a storage disk, and means for writing on and reading data from the storage disk, the spindle motor having a fluid dynamic bearing system and comprising:
 a stationary shaft ( 12 ;  212 ;  312 ) that is held directly or indirectly in a baseplate ( 10 ,  210 ;  310 ),   a rotor component ( 14 ,  114 a;  214 ;  314 a-c) rotatably supported with respect to the shaft about a rotational axis ( 46 ;  246 ;  346 ),   bearing gap ( 20 ,  220 ;  320 ) open at both ends filled with a bearing fluid that separates the adjoining surfaces of the shaft ( 12 ;  212 ;  312 ), the rotor component ( 14 ,  114 a;  214 ;  214 a-c) and at least one first bearing part ( 16 ,  216 ;  316 ) from one another, a first radial bearing ( 22 a,  222 a;  322 a) and a second radial bearing ( 22 b,  222 b;  322 b) formed between the opposing axially extending bearing surfaces of the shaft ( 12 ;  212 ;  312 ) and the rotor component ( 14 ,  114 a;  214 ;  314 a-c),   an axial bearing ( 26 ,  226 ;  326 ) formed between the opposing radially extending bearing surfaces of the rotor component ( 14 ,  114 a;  214 ;  314 a-c) and the first bearing part ( 16 ,  216 ;  316 ) connected to the baseplate,   a recirculation channel ( 28 ;  128 ;  228 ;  328 ) filled with bearing fluid that connects the remote regions of the bearing to each other, and   an electromagnetic drive system ( 42 ,  44 ;  342 ,  244 ) for driving the rotor component,   characterized in that the recirculation channel ( 28 ,  128 ;  228 ) ends in a gap ( 21 ) radially outside of the bearing gap ( 20 ) of the axial bearing ( 26 ), and   further characterized in that the width of the gap ( 21 ) is greater than or equal to the width of the bearing gap ( 20 ) of the axial bearing ( 26 ) plus the depth of the bearing patterns of the axial bearing ( 26 ).   
     
     
       31. A spindle motor having a fluid dynamic bearing system comprising:
 a stationary shaft ( 12 ;  212 ;  312 ) that is held directly or indirectly in a baseplate ( 10 ,  210 ;  310 ),   a rotor component ( 14 ,  114 a;  214 ;  314 a-c) rotatably supported with respect to the shaft about a rotational axis ( 46 ;  246 ;  346 ),   a bearing gap ( 20 ,  220 ;  320 ) open at both ends filled with a bearing fluid that separates the adjoining surfaces of the shaft ( 12 ;  212 ;  312 ), the rotor component ( 14 ,  114 a;  214 ;  214 a-c) and at least one first bearing part ( 16 ,  216 ;  316 ) from one another, a first radial bearing ( 22 a,  222 a;  322 a) and a second radial bearing ( 22 b,  222 b;  322 b) formed between the opposing axially extending bearing surfaces of the shaft ( 12 ;  212 ;  312 ) and the rotor component ( 14 ,  114 a;  214 ;  314 a-c),   an axial bearing ( 26 ,  226 ;  326 ) formed between the opposing radially extending bearing surfaces of the rotor component ( 14 ,  114 a;  214 ;  314 a-c) and the first bearing part ( 16 ,  216 ;  316 ) connected to the baseplate,   a recirculation channel ( 28 ;  128 ;  228 ;  328 ) filled with bearing fluid that connects the remote regions of the bearing to each other, and   an electromagnetic drive system ( 42 ,  44 ;  342 ,  244 ) for driving the rotor component,   characterized in that the recirculation channel ( 28 ,  128 ;  228 ) is disposed in the rotor component ( 14 ;  114 a;  214 ) and connects a sealing gap ( 34 ) radially outside the axial bearing ( 26 ) to a section of the bearing gap ( 20 ) adjacent to a dynamic pumping seal ( 136 ).   
     
     
       32. A spindle motor having a fluid dynamic bearing system comprising:
 a stationary shaft that is held directly or indirectly in a baseplate;   a rotor component rotatably supported with respect to the shaft about a rotational axis;   a bearing gap open at both ends filled with a bearing fluid, the bearing gap separating adjoining surfaces of the shaft and the rotor component, the bearing gap further separating adjoining surfaces of the rotor component and at least a first bearing part;   a first radial bearing and a second radial bearing formed between the opposing axially extending bearing surfaces of the shaft and the rotor component;   an axial bearing formed between the opposing radially extending bearing surfaces of the rotor component and the first bearing part connected to the baseplate;   a recirculation channel filled with bearing fluid that connects the remote regions of the bearing to each other, the recirculation channel ending in a first gap radially outside of a second gap, the width of the first gap being greater than the width of the second gap, the first gap and the second gap being located at the same side as the axial bearing, a bearing pattern of the axial bearing being formed at least at the second gap, the axial bearing comprising spiral-shaped bearing patterns; and   an electromagnetic drive system for driving the rotor component.    
     
     
       33. A spindle motor according to claim 32, wherein the rotor component comprises an inner, sleeve-shaped rotor component and an outer cup-shaped rotor component.  
     
     
       34. A spindle motor according to claim 33, wherein the inner, sleeve-shaped rotor component is enclosed by a further, sleeve-shaped rotor component on which the outer cup-shaped rotor component is disposed.  
     
     
       35. A spindle motor according to claim 32, wherein the rotor component is a single piece taking the form of a hub/bearing bush arrangement.  
     
     
       36. A spindle motor according to claim 32, wherein the first bearing part is integrally formed with the shaft as one piece.  
     
     
       37. A spindle motor according to claim 32, wherein a second bearing part is integrally formed with the shaft as one piece.  
     
     
       38. A spindle motor according to claim 32, wherein a capillary gap seal is formed between an inner surface of the rotor component and an outer surface of a second bearing part.  
     
     
       39. A spindle motor according to claim 32, wherein a capillary gap seal is formed between an outer surface of the rotor component and an inner surface of the first bearing part.  
     
     
       40. A spindle motor according to claim 32, wherein the recirculation channel is disposed in the rotor component and connects the sealing gap radially outside the axial bearing to a section of the bearing gap located radially outside a dynamic pumping seal.  
     
     
       41. A spindle motor according to claim 32, wherein the recirculation channel is disposed at an incline to the rotational axis, which, on rotation of the rotor component, causes a centrifugal force to be exerted on the bearing fluid held in the recirculation channel, the centrifugal force transporting the bearing fluid through the recirculation channel toward the first bearing part.  
     
     
       42. A spindle motor according to claim 41, wherein the recirculation channel is inclined at an angle of 5 to 15 degrees with respect to the rotational axis.  
     
     
       43. A spindle motor according to claim 41, wherein the centrifugal force exerted on the bearing fluid due to the inclined recirculation channel positively supports a circulation of the bearing fluid, the circulation generated by an overall pumping effect of the axial bearing and the radial bearings.  
     
     
       44. A spindle motor according to claim 43, wherein the pumping force generated by the centrifugal force is directed to the axial bearing.  
     
     
       45. A spindle motor according to claim 43, wherein the centrifugal force is at least twice as big as the force exerted on the bearing fluid due to the overall pumping effect of the axial bearing and the radial bearings.  
     
     
       46. A spindle motor according to claim 32, wherein a dynamic pumping seal is formed between opposing radially extending surfaces of the rotor component and a second bearing part connected to the shaft.  
     
     
       47. A spindle motor according to claim 46, wherein the dynamic pumping seal is formed between a radially extending end face of the rotor component and an adjoining radially extending end face of the second bearing part.  
     
     
       48. A spindle motor according to claim 46, wherein the dynamic pumping seal is disposed substantially perpendicular to the rotational axis and the sealing gap of the gap seal is substantially parallel to the rotational axis.  
     
     
       49. A spindle motor according to claim 32, wherein a ferromagnetic ring is disposed axially opposite a rotor magnet of the electromagnetic drive system, the ferromagnetic ring and rotor magnet generating a magnetic force that is directed in the opposite direction to a bearing force generated by the axial bearing.  
     
     
       50. A spindle motor according to claim 32, wherein the electromagnetic drive system comprises a stator arrangement which is disposed at an axial offset with respect to the rotor magnet and generates a magnetic force that is directed in the opposite direction to a bearing force generated by the axial bearing.  
     
     
       51. A spindle motor according to claim 32, wherein adjacent surfaces of a second bearing part and the rotor component form a further axial bearing.  
     
     
       52. A spindle motor according to claim 32, wherein a third bearing part connected to the rotor component adjoins a second bearing part, a pumping seal being disposed between the second and the third bearing parts and a sealing gap being disposed between the third bearing part and the shaft.  
     
     
       53. A spindle motor according to claim 32, wherein the rotor component comprises an inner part and an outer part, and wherein the recirculation channel is disposed between the inner part and the outer part and connects the sealing gap radially outside the axial bearing to a section of the bearing gap located radially outside a second axial bearing.  
     
     
       54. A spindle motor according to claim 32, wherein a dynamic pumping seal is formed between opposing axially extending surfaces of the rotor component and a second bearing part connected to the shaft.  
     
     
       55. A spindle motor according to claim 32, wherein the bearing pattern of the axial bearing extends over an entire end face of the rotor component or an entire first bearing part from an inside rim to an outer rim.  
     
     
       56. A spindle motor having a fluid dynamic bearing system comprising:
 a stationary shaft that is held directly or indirectly in a baseplate;   a rotor component rotatably supported with respect to the shaft about a rotational axis;   a bearing gap open at both ends filled with a bearing fluid, the bearing gap separating adjoining surfaces of the shaft and the rotor component, the bearing gap further separating adjoining surfaces of the rotor component and at least a first bearing part;   a first radial bearing and a second radial bearing formed between the opposing axially extending bearing surfaces of the shaft and the rotor component;   an axial bearing formed between the opposing radially extending bearing surfaces of the rotor component and the first bearing part connected to the baseplate;   a recirculation channel filled with bearing fluid that connects the remote regions of the bearing to each other, the recirculation channel ending in a gap radially outside of the bearing gap of the axial bearing, the gap being at the same axial position as the bearing gap of the axial bearing, the width of the gap being greater than the width of the bearing gap of the axial bearing;   an electromagnetic drive system for driving the rotor component; and   a sealing gap for sealing the bearing gap which is covered by an annular cover connected to the rotor component, the annular cover being connected to an outer circumferential surface of the rotor component or to a recess positioned at an end face of the rotor component.    
     
     
       57. A spindle motor according to claim 56, wherein the sealing gap is formed between an inner circumferential surface of the rotor component and an outer circumferential surface of a second bearing part.  
     
     
       58. A spindle motor according to claim 56, wherein the sealing gap is formed between an outer circumferential surface of the rotor component and an inner circumferential surface of the first bearing part.  
     
     
       59. A spindle motor according to claim 56, wherein the sealing gap extends substantially parallel to the rotational axis or is inclined at an acute angle to the rotational axis.  
     
     
       60. A spindle motor according to claim 56, wherein surfaces of the rotor component and the first bearing part form another sealing gap, said another sealing gap extending substantially parallel to the rotational axis or being inclined at an acute angle to the rotational axis.  
     
     
       61. A spindle motor according to claim 60, wherein the another sealing gap is formed between an outer circumferential surface of the rotor component and an inner circumferential surface of the first bearing part.  
     
     
       62. A spindle motor according to claim 56, wherein the annular cover is formed by the rotor component.  
     
     
       63. A spindle motor according to claim 56, wherein the sealing gap is formed between an inner circumferential surface of the cover and an outer circumferential surface of a second bearing part.  
     
     
       64. A spindle motor according to claim 56, wherein the annular cover and a second bearing part form a labyrinth seal.  
     
     
       65. A spindle motor according to claim 56, wherein the sealing gap is formed between an end face of the rotor component and an end face of a second bearing part.  
     
     
       66. A spindle motor having a fluid dynamic bearing system comprising:
 a stationary shaft that is held directly or indirectly in a baseplate;   a rotor component rotatably supported with respect to the shaft about a rotational axis;   a bearing gap open at both ends filled with a bearing fluid, the bearing gap separating adjoining surfaces of the shaft and the rotor component, the bearing gap further separating adjoining surfaces of the rotor component and at least a first bearing part;   a first radial bearing and a second radial bearing formed between the opposing axially extending bearing surfaces of the shaft and the rotor component;   an axial bearing formed between the opposing radially extending bearing surfaces of the rotor component and the first bearing part connected to the baseplate;   a recirculation channel filled with bearing fluid that connects the remote regions of the bearing to each other, the recirculation channel ending in a first gap radially outside of a second gap, the width of the first gap being greater than or equal to the width of the second gap plus the depth of bearing patterns of the axial bearing, the first gap and the second gap being located at the same side as the axial bearing, a bearing pattern of the axial bearing being formed at least at the second gap, the axial bearing comprising spiral-shaped bearing patterns; and   an electromagnetic drive system for driving the rotor component.    
     
     
       67. A hard disk drive comprising a spindle motor for rotatably driving at least a storage disk, and means for writing on and reading data from the storage disk, the spindle motor having a fluid dynamic bearing system and comprising:
 a stationary shaft that is held directly or indirectly in a baseplate;   a rotor component rotatably supported with respect to the shaft about a rotational axis;   a bearing gap open at both ends filled with a bearing fluid, the bearing gap separating adjoining surfaces of the shaft and the rotor component, the bearing gap further separating adjoining surfaces of the rotor component and at least a first bearing part;   a first radial bearing and a second radial bearing formed between the opposing axially extending bearing surfaces of the shaft and the rotor component;   an axial bearing formed between the opposing radially extending bearing surfaces of the rotor component and the first bearing part connected to the baseplate;   a recirculation channel filled with bearing fluid that connects the remote regions of the bearing to each other, the recirculation channel ending in a first gap radially outside of a second gap, the width of the first gap being greater than or equal to the width of the second gap plus the depth of the bearing patterns of the axial bearing, the first gap and the second gap being located at the same side as the axial bearing, a bearing pattern of the axial bearing being formed at least at the second gap, the axial bearing comprising spiral-shaped bearing patterns; and   an electromagnetic drive system for driving the rotor component.    
     
     
       68. A spindle motor having a fluid dynamic bearing system comprising:
 a stationary shaft that is held directly or indirectly in a baseplate;   a rotor component rotatably supported with respect to the shaft about a rotational axis;   a bearing gap open at both ends filled with a bearing fluid, the bearing gap separating adjoining surfaces of the shaft and the rotor component, the bearing gap further separating adjoining surfaces of the rotor component and at least a first bearing part;   a first radial bearing and a second radial bearing formed between the opposing axially extending bearing surfaces of the shaft and the rotor component;   an axial bearing formed between the opposing radially extending bearing surfaces of the rotor component and the first bearing part connected to the baseplate;   a recirculation channel filled with bearing fluid that connects the remote regions of the bearing to each other, the recirculation channel being disposed in the rotor component and connecting a first sealing gap radially outside the axial bearing to a section of the bearing gap adjacent to a dynamic pumping seal, the dynamic pumping seal being positioned between an upper end of the recirculation channel and a second sealing gap; and   an electromagnetic drive system for driving the rotor component.