Method for manufacturing a tool that is used to form dynamic pressure generating grooves in dynamic pressure bearing devices

The present invention relates to a dynamic pressure bearing apparatus and a method for manufacturing thereof and to a tool for forming a dynamic pressure generating groove in the apparatus and a method for manufacturing the groove, in which a dynamic pressure is generated in a lubricating fluid wherein a fixed member and a rotatable member hold each other relatively rotatable due to the dynamic pressure. A method for manufacturing a tool to form a dynamic pressure bearing in which at least one of the bearing surfaces has a plurality of pressure generating grooves defined by projections and in which lubricating fluid is contained in the grooves to provide lubrication between the bearing surfaces when they rotate relative to one another. A flat bevel is created at one or more of the corners of each of the projections that define the grooves thereby generating a wedge-shaped space that communicates between the grooves and the gap between the bearing surfaces. This wedge-shaped space facilitates passage of lubricating fluid from the groove to the gap when movement, normally rotation, occurs between the two bearing surfaces thereby minimizing wear between the surfaces.