METHOD OF MANUFACTURING A THRUST PLATE, METHOD OF MANUFACTURING A SHAFT FOR A HYDRODYNAMIC BEARING, HYDRODYNAMIC BEARING, SPINDLE MOTOR, AND RECORDING DISK DRIVE DEVICE

摘要

A method of manufacturing a thrust plate for a dynamic pressure bearing in which the upper and lower end surfaces thereof have a highly precise perpendicular angle relative to the central axis thereof. The thrust plate has an annular shape, and a central hole is formed therein in which is fitted a shaft body. Thrust surfaces that form a portion of thrust bearing units are formed at both end surfaces of the thrust plate. The method of manufacturing the thrust plate includes a blanking step in which a plate-like work piece is press-cut to obtain an annular blank intermediate, an end surface polishing step in which both end surfaces of the blank intermediate are polished, and a shaving step in which an inner hole and an outer periphery of the polished blank intermediate are simultaneously press-cut to shave off surfaces thereof.