Patent ID: 6698097
Filing Date: 2004-03-02
Classification: F16C,Y10T

Abstract:
A method for manufacturing a tool for forming dynamic pressure generating grooves used in a method for manufacturing a dynamic pressure bearing apparatus in which:an ion-milling apparatus is placed across from a blank for a tool for forming dynamic pressure generating grooves wherein said tool is made of a coining punch or a mold; and a concave portion for forming a projecting portion on a thrust dynamic pressure bearing surface is formed for a given depth on said blank for a tool for forming dynamic pressure generating grooves by ion irradiation from said ion-milling apparatus; wherein: a first direction, which is perpendicular to said end surface of said blank, and a second direction, which is equal to the direction of ion irradiation from said ion-milling apparatus, are directed to form a given angle; said ion irradiation is performed when one of said first and second directions is rotated around another direction as an axis while maintaining said angle between said directions such that a slanted surface, in which the depth becomes continuously shallow starting from the center of said concave portion for forming a projecting portion towards a side wall, is formed at a position on said blank corresponding to a bottom corner of said concave portion for forming a projecting portion; and the given angle between the first and second directions acts to intermittently irradiate a part of the concave portion during rotation to form the slanted surface.