Patent ID: 6854889
Filing Date: 2005-02-15
Classification: F16C

Abstract:
1. A hydrodynamic bearing comprising: a shaft defining a rotational center axis; an annular thrust plate provided on, and projecting radially outward from, the outer circumferential surface of said shaft, said thrust plate having an approximately conical form in which at least a portion of said thrust plate shrinks in outer diameter with increasing separation from one of the axial faces of said thrust plate, the outer peripheral surface of said portion therein formed in a sloping-face contour; a hollow round cylindrical sleeve in which are formed a stepped portion opposing both the outer circumferential surface of, and said one of the axial faces of, said thrust plate, and continuous with said stepped portion, a radial inner-peripheral surface radially opposing the outer circumferential surface of said shaft via a micro-gap; and a ring-shaped member the inner peripheral surface of which is formed into a sloping-face contour such that heading toward its radially outward side from its inward side the inner diameter expands, fitted on an inner circumferential surface of said stepped portion opposing the outer peripheral surface of said sloping-face contour of said thrust plate; wherein lubricant is retained, and dynamic-pressure-generating grooves for inducing dynamic pressure in said lubricant are provided, in between the outer circumferential surface of said shaft and the radial inner-peripheral surface of said sleeve, whereby a radial bearing section is configured, lubricant is retained, and dynamic-pressure-generating grooves for inducing dynamic pressure in said lubricant are provided, in between said stepped portion and said one of the axial faces of said thrust plate, whereby a thrust bearing section is configured, a taper seal section that, with respect to the rotational center axis, slopes heading toward its radially inward side from its outward side, and whose gap clearance dimension gradually expands with increasing separation from said thrust bearing section, is formed in between said ring-shaped member and said approximately conical form of the thrust plate, and said lubricant retained in said thrust bearing section forms an interface within said taper seal section.