Hydrodynamic bearing device

摘要

A hydrodynamic bearing device has favorable bearing performance and long endurance life. A thrust bearing part of the hydrodynamic bearing device has a second thrust surface. In the second thrust surface, a dynamic pressure generating groove area having a plurality of dynamic pressure generating grooves is formed in at least a part thereof in a radial direction. The action of dynamic pressure of lubricating oil increases the pressure in a thrust bearing clearance between an end of a flange part of an axial member and the second thrust surface, to support the axial member in an axial direction in a non-contact manner. The dynamic pressure generating groove area of the second thrust surface is formed by press working. The difference in height between the inner and outer peripheral edges of the surface of the dynamic pressure generating groove area regulated between or equal to 0 and 2 μm.