A hydrodynamic bearing assembly (10) includes a bearing sleeve (11) defining a receiving chamber (113) therein, a bearing (12) received in the receiving chamber of the bearing sleeve, a sealing cover (15) mounted to an open end (112) of the bearing sleeve and including an enlarged section (153) adjacent to the bearing, a shaft (13) extending through the sealing cover and rotatably disposed in the bearing, on which a plurality lubricant pressure generating grooves are defined, and a lubricant retaining space (117) defined by the enlarged section of the sealing cover, an end of the bearing and the shaft for receiving lubricant therein. One of the sealing cover and the shaft defines a groove (134) therein, while the other one of the sealing cover and the shaft extends a flange (156) into the groove.