Patent ID: 7736061
Filing Date: 2010-06-15
Classification: F16C,G11B,H02K

Abstract:
1. A fluid dynamic bearing comprising: a shaft member including a substantially cylindrical portion and a circular plate extending radially outward from the cylindrical portion; a support including a cylinder having a closed end and rotatably accommodating the cylindrical portion, and a flange-shaped thrust bearing portion extending radially outward from the cylinder; a stopper engaged with the circular plate such that the thrust bearing portion is held therebetween; and a working fluid filling gaps between the shaft member and the support and between the support and the stopper; wherein pressure-generating grooves are provided in opposed thrust surfaces of the thrust bearing portion that are opposite the circular plate and the stopper to attract the working fluid from inner and outer edges of the thrust bearing portion to a radially midway portion thereof as the shaft member rotates relative to the support; and wherein one or more through-holes are provided between inner edges of annular regions of the thrust surfaces in which the pressure-generating grooves are provided and the midway portion in the radial direction, each through-hole extending through the thrust bearing portion in a central-axis direction of the shaft member and being positioned to interconnect pressure generating grooves in the opposed thrust surfaces.