FLUID DYNAMIC PRESSURE BEARING DEVICE

摘要

An internal peripheral surface (8a) and a bottom end surface (8b) of a bearing sleeve (8) made of sintered metal are made into a smooth cylindrical surface or a flat surface having no dynamic pressure generator, whereby a dynamic pressure generator molding step can be omitted from the steps of manufacturing the bearing sleeve (8), and die cost can be greatly reduced. The internal peripheral surface (8a) of the bearing sleeve (8) is made into a cylindrical surface, whereby a radial dynamic pressure generator is formed on an external peripheral surface (2a1) of a shaft (2a), and the radial dynamic pressure generator is formed in a simple manner with good precision because the external peripheral surface (2a1) of the shaft (2a) is readily accessible by a tool, and bearing rigidity is increased by improving the precision of a radial bearing gap.