Spindle motor and manufacturing method thereof

Abstract

A spindle motor having a pivot which tip portion can easily be formed by a spherical surface having high precision, high hardness, the diameter of which can be determined as desired, the tip portion 6 a of the pivot 6 is formed by cutting a steel ball used in a bearing or the like having any diameter. The pivot 6 having a spherical surface 6 a is formed by fixing the pivot tip portion 6 a to one side surface 6 c of a substantially cylindrical shaft portion 6 b . As a result, the spherical surface having a high precision, high hardness which diameter can be determined as desired can easily be formed at the tip portion 6 a of the pivot 6.

What is claimed is:  
     
         1 . A method for manufacturing a spindle motor comprising; 
 a rotor in which a pivot having a spherical surface at a tip portion rotates in unity with a hub,    a stator having a substantially cylindrical stationary shaft uprightly and coaxially with said pivot, said stator having a sleeve abutting to the inner surface of said shaft, said pivot inserted into said sleeve within a minute gap,    a thrust plate for closing an opening on one side of said stationary shaft and for supporting a spherical surface formed at the tip portion of said pivot,    a fluid which is filled in said minute gap formed between said pivot and said sleeve and in a space above an upper face of said thrust plate which space communicating to said minute space between said pivot and said sleeve,    the method comprising: 
 a process for cross sectionally cutting a steel ball which forms a tip portion on said pivot, and  
 a process of fixing one end of said pivot to one side surface of said shaft.