Abstract: A cooling fan includes a fan housing (10) having a central tube (18) extending upwardly therein. A sleeve bearing (40) is received in the central tube. A stator (20) is mounted around the central tube. A rotor (30) has a shaft (36) being rotatably received in the sleeve bearing. The sleeve bearing defines a bearing hole (42) therethrough. The bearing hole (42) receives the shaft of the rotor to rotate therein. A plurality of irregular pores and at least one blind hole (44) are defined in the sleeve bearing and impregnated with lubricant oil.

Abstract: A hydrodynamic bearing assembly includes a bearing (10) with at least an end thereof being opened and a shaft (38) rotatably disposed in the bearing. A bearing clearance is formed between an outer surface of the shaft and an inner surface of the bearing and is filled with lubricant. A plurality of lubricant pressure generating grooves (14) are axially set on at least one of the inner surface of the bearing and the outer surface of the shaft. Each of the lubricant pressure generating grooves includes two symmetrical branches (141, 142) and has a V-shaped cross section.

Abstract: A cooling fan includes a fan housing (10) having a central tube (15) extending upwardly therefrom, a bearing (20) defining a bearing hole (22) therein, a stator (30) mounted on the central tube, and a rotor (40) including a hub (12) having a shaft (18) extending from the hub into the bearing hole of the bearing. The bearing is received and fixedly connected to the central tube during the plastic injection molding of the fan housing; thus the bearing and the central tube are integrally connected together. The bearing can be precisely and firmly secured to the central tube of the fan housing.

Abstract: A bearing assembly includes a bearing (10) having a bearing surface (16) defining a bearing hole (12) therein and a shaft (20) disposed in the bearing hole of the bearing. The bearing has an open end for the shaft insertion therethrough into the bearing hole along an axial direction of the bearing. The shaft defines a notch (24) in an outer periphery thereof, which is located corresponding to the open end of the bearing. A plurality of spiral grooves (228) are defined in the outer periphery of the shaft above the notch. A rotation direction of the shaft is the same as a spiral direction of the grooves during rotation of the shaft. A cover (50) covers the open end of the bearing and closely surrounds the grooves of the shaft.