Abstract: A cooling fan includes a fan housing (30) having a central tube (34) extending upwardly therefrom, a bearing (60) being received in the central tube, a stator (20) being mounted around the central tube, and a rotor (10) having a shaft (18) extending through the bearing. At least one notch (180, 184) is defined in an end of the shaft. A balance structure (62) is mounted around the shaft, and has a portion facing and surrounding an upper portion of the at least one notch of the shaft. The balance structure is made of magnetic material, which can attract the shaft downward to thereby counter the upward force generated by the rotor when it is driven to rotate. Accordingly, the noise problem incurred by the floating of the rotating rotor can be resolved by the present invention.

Abstract: A cooling fan includes a fan housing (10) having a shaft seat (16) extending downwardly therefrom, a stator (20) being fixedly mounted around the shaft seat, a shaft (80) with a top end being fixedly connected to the shaft seat and a free end (82) extending downwardly therefrom, a rotor (30) comprising a hub (32) having a plurality of blades (34) extending radially and outwardly, and a sleeve bearing (40). A fixing tube (36) extends upwardly from a center of the hub. The fixing tube has a closed bottom end and defines a fixing hole (360) therein. The sleeve bearing is fixedly received in the fixing hole of the fixing tube to rotate with the rotor. A bearing hole is defined in the sleeve bearing for extension of the free end of the shaft therethrough.

Abstract: A cooling fan includes a fan housing (10) having a central tube (11) extending upwardly therefrom, a bearing (20) received in the central tube, a stator (40) mounted around the central tube, a rotor (30) having a shaft (37) extending into the bearing, and a magnetic ring (38) being fixedly mounted to the rotor to rotate with the rotor during operation of the cooling fan. The bearing is made of iron-copper alloy. The magnetic ring is made of hard magnetic material and exerts a magnetic attraction on the bearing, whereby the rotor is pulled downwardly by a magnetic attraction of the bearing on the magnetic ring to lessen the floating problem of the rotor during operation of the cooling fan.

Abstract: A cooling fan includes a fan housing (10) having a shaft seat (16) extending downwardly therefrom, a stator (20) being fixedly mounted around the shaft seat, a shaft (80) with a top end being fixedly connected to the shaft seat and a free end (82) extending downwardly therefrom, a rotor (30) comprising a hub (32) having a plurality of blades (34) extending radially and outwardly, and a sleeve bearing (40). A fixing tube (36) extends upwardly from a center of the hub. The fixing tube has a closed bottom end and defines a fixing hole (360) therein. The sleeve bearing is fixedly received in the fixing hole of the fixing tube to rotate with the rotor. A bearing hole is defined in the sleeve bearing for extension of the free end of the shaft therethrough.

Abstract: A cooling fan includes a fan housing (30) having a central tube (34) extending upwardly therefrom, a bearing (60) being received in the central tube, a stator (20) being mounted around the central tube, and a rotor (10) having a shaft (18) extending through the bearing. At least one notch (180, 184) is defined in an end of the shaft. A balance structure (62) is mounted around the shaft, and has a portion facing and surrounding an upper portion of the at least one notch of the shaft. The balance structure is made of magnetic material, which can attract the shaft downward to thereby counter the upward force generated by the rotor when it is driven to rotate. Accordingly, the noise problem incurred by the floating of the rotating rotor can be resolved by the present invention.

Abstract: A cooling fan includes a fan housing (10) having a central tube (11) extending upwardly therefrom, a bearing (20) received in the central tube, a stator (40) mounted around the central tube, a rotor (30) having a shaft (37) extending into the bearing, and a magnetic ring (38) being fixedly mounted to the rotor to rotate with the rotor during operation of the cooling fan. The bearing is made of iron-copper alloy. The magnetic ring is made of hard magnetic material and exerts a magnetic attraction on the bearing, whereby the rotor is pulled downwardly by a magnetic attraction of the bearing on the magnetic ring to lessen the floating problem of the rotor during operation of the cooling fan.