Patent ID: 7946770
Filing Date: 2011-05-24
Classification: B21J,B21K,F16C

Abstract:
1. A hydrodynamic bearing device comprising: an axial member having a first thrust surface; and a second thrust surface opposed to the first thrust surface of the axial member in an axial direction, a dynamic pressure generating groove area being formed in one of the first thrust surface and the second thrust surface, the dynamic pressure generating groove area having a plurality of dynamic pressure generating grooves and ridges, an action of dynamic pressure of a fluid generating a pressure in a thrust bearing clearance between the first thrust surface and the second thrust surface to support the axial member in the axial direction in a non-contact manner, wherein the dynamic pressure generating groove area is formed by press working, and a difference in height (H wherein in the one of the first thrust surface and the second thrust surface having the dynamic pressure generating groove area, an inner surface surrounded by the inner peripheral edge of the dynamic pressure generating groove area is lower in height than an innermost one of the ridges, wherein each of the ridges has a slop top surface for gradually descending required by the difference in height (H