Heat dissipation fan

A heat dissipation fan includes a rotor (1) having a hub (10) with a permanent magnet (104) attached to an inner surface thereof, a stator (2) and a fan frame (3) having a bearing seat (36). The bearing seat (36) includes a base (361) and a central tube (362) around which the stator is mounted. Slots (102) are defined through the top wall of the hub facing to the magnet ring. The base defines slots (360), corresponding to the slots of the hub.

TECHNICAL FIELD

The present invention relates to a fan, and more particularly to a heat dissipation fan having a permanent magnet easily to be assembled and disassembled.

BACKGROUND

Referring toFIG. 5, a conventional fan mainly comprises a rotor1′, a stator2′, and a housing3′. The rotor1′ comprises a hub10′ with a close end wall and a mouth opposing the close end wall. A number of blades11′ extend radially outward from the hub10′. A permanent magnet104′ is fixedly mounted to the inner surface of the hub10′ via the mouth after the hub10′ is formed. However, it is very hard to accurately locate the permanent magnet104′ in the hub10′. Furthermore, when any components of the rotor1′ other than the permanent magnet104′ is damaged, it is not convenient for tools to enter into the hub10′ from the mouth of the hub10′ to detach the permanent magnet104′ from the hub10′.

Moreover, in operation of the fan, coils of the stator2′ are electrified to allow the rotor1′ to rotate circumambiently around the stator2′. Therefore, coils of the stator2′ generate heat continuously. The heat generated by the coil due to electrification of the fan will accumulate within the fan if it is not removed efficiently, which leads to the damage of the fan.

An improved fan that overcomes the above-mentioned disadvantages is desired.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a heat dissipation fan having a permanent magnet easily to be assembled and disassembled.

Another object of the present invention is to provide a heat dissipation fan which can dissipate internal heat generated by the heat dissipating fan.

To achieve the above-mentioned objects, a heat dissipation fan comprises a rotor having a hub with a permanent magnet attached to an inner surface thereof, a stator and a fan frame having a bearing seat. The bearing seat comprises a base and a central tube around which the stator is mounted. Slots are defined through the top wall of the hub facing to the magnet ring. The base defines corresponding slots, corresponding to the slots of the hub.

Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of the preferred embodiments of the present invention with attached drawings, in which:

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring toFIG. 1andFIG. 2, a heat dissipation fan includes a motor and a fan frame3. The motor comprises a rotor1and a stator2.

The rotor1comprises a hub10having a circular top wall and a circumferential wall depending from the top wall. The hub10comprises a central shaft12and a set of blades11extending radially outward from the shaft12. A permanent magnet104is attached to an inner surface of the circumferential wall of the hub10. A plurality of splaced slots102is defined through the top wall of the hub10over the permanent magnet104. The slots102are located at an concentric circle and elongated in the circumferential direction of the circle for facilitating an auxiliary tool to enter into the hub10from above the hub10. The permanent magnet104is mounted in the hub10from the bottom of the hub10by means of the auxiliary tool (not shown) that extends through the slots102to locate the permanent magnet104in the hub10. Thus, an acceptable precision is achieved.

The stator comprises a core20, a coil22and a circuit board24having a circuit to control the motor.

The fan frame3is formed from a plastic material, and comprises a pedestal30and a cylindrical wall32extending upwardly from the edge of the pedestal30. The pedestal30comprises a bearing seat36. The bearing seat36comprises a base361and a central tube362extending upwardly from the top surface of the base361. Slots360corresponding to the slots102of the hub10are defined in the base361beneath the hub10.

Referring toFIGS. 3-5, the stator2is mounted on the outer periphery of the bearing seat36. The shaft12of the rotor1is inserted in the central tube362and the permanent magnet surrounds and confronts the stator2. The slots360of the fan frame3align with the corresponding slots102of the hub10. When the heat dissipation fan is in operation, the coil20is electrified to generate magnetic field which interacts with the permanent magnet104of the rotor1to drive the rotor1to rotate. Ambient air is forced into the hub10via the slots102and out of the hub10via the slots360. Internal heat generated by the stator2is carried away by the ambient air.

In the heat dissipation fan described above, when any components of the rotor1other than the permanent magnet104is damaged, the permanent magnet104can be easily pushed out of the hub10by a tool that extends through the slots102of the hub10so that the permanent magnet104is recycled and the cost is saved.

It is understood that the invention may be embodied in other forms without departing from the spirit thereof. The above-described examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given above.