Hydrodynamic bearing and method for manufacturing the same, and spindle motor and method for manufacturing the same

Abstract

The object of the present invention is to provide a hydrodynamic bearing, a method for manufacturing the same, and a spindle motor, with which the gap in the axial direction required for the smooth operation of a bearing can be sufficiently ensured. A method for manufacturing a hydrodynamic bearing comprising a shaft 7 , a sleeve 8 attached so as to be capable of relative rotation with respect to the shaft 7 , a first flange unit 6 fixed to or integrated with the shaft 7 , and a second flange unit 9 fixed to the shaft 7 , the method comprising at least inserting the shaft 7 into the sleeve 8 , and inserting the shaft 7 into the second flange unit 9 , pressing the top face of the second flange unit 9 in the axial direction, and fixing the second flange unit 9 to the shaft 7 by welding the shaft 7 and the second flange unit 9 while maintaining the pressing state.

1 . A method for manufacturing a hydrodynamic bearing comprising:
 a shaft;   a sleeve attached so as to be capable of relative rotation with respect to the shaft;   a first flange unit fixed to or integrated with the shaft; and   a second flange unit fixed to the shaft,   the method comprising:   inserting the sleeve into the shaft, and inserting the second flange unit into the shaft;   pressing the top face of the second flange unit in the axial direction; and   fixing the second flange unit to the shaft by welding the shaft and the second flange unit while keeping pressing the top face of the second flange unit.   
   
   
       2 . The method for manufacturing a hydrodynamic bearing according to  claim 1 , further comprising:
 coating the welded portion with an adhesive resin.   
   
   
       3 . The method for manufacturing a hydrodynamic bearing according to  claim 1 ,
 wherein while pressing the top face of the second flange unit in the axial direction, the top face of the shaft is also pressed in the axial direction.   
   
   
       4 . The method for manufacturing a hydrodynamic bearing according to  claim 3 ,
 wherein the shaft has a threaded hole in its end face, and   while pressing the top face of the second flange unit in the axial direction, the top face of the shaft is pressed in the axial direction while the threaded hole is blocked off.   
   
   
       5 . The method for manufacturing a hydrodynamic bearing according to  claim 1 ,
 wherein while pressing the top face of the second flange unit in the axial direction, a holding jig is used to press the top face of the shaft in the axial direction.   
   
   
       6 . The method for manufacturing a hydrodynamic bearing according to  claim 5 ,
 wherein the holding jig has elasticity.   
   
   
       7 . The method for manufacturing a hydrodynamic bearing according to  claim 5 ,
 wherein the holding jig has a spherical shape at its distal end.   
   
   
       8 . The method for manufacturing a hydrodynamic bearing according to  claim 1 ,
 wherein the first flange unit is fixed to the shaft by welding.   
   
   
       9 . The method for manufacturing a hydrodynamic bearing according to  claim 1 ,
 wherein the second flange unit has a concave part on the inner peripheral side of the top face in the axial direction, and   while fixing the second flange unit to the shaft by welding the shaft and the second flange unit, the welding is performed near the boundary between the concave part and the shaft.