Heat dissipation fan

[0001] 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.

[0002] Referring to FIG. 5, a conventional fan mainly comprises a rotor 1′, a stator 2′, and a housing 3′. The rotor 1′ comprises a hub 10′ with a close end wall and a mouth opposing the close end wall. A number of blades 11′ extend radially outward from the hub 10′. A permanent magnet 104′ is fixedly mounted to the inner surface of the hub 10′ via the mouth after the hub 10′ is formed. However, it is very hard to accurately locate the permanent magnet 104′ in the hub 10′. Furthermore, when any components of the rotor 1′ other than the permanent magnet 104′ is damaged, it is not convenient for tools to enter into the hub 10′ from the mouth of the hub 10′ to detach the permanent magnet 104′ from the hub 10′.

[0003] Moreover, in operation of the fan, coils of the stator 2′ are electrified to allow the rotor 1′ to rotate circumambiently around the stator 2′. Therefore, coils of the stator 2′ 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.

[0004] An improved fan that overcomes the above-mentioned disadvantages is desired.

[0005] Accordingly, an object of the present invention is to provide a heat dissipation fan having a permanent magnet easily to be assembled and disassembled.

[0006] Another object of the present invention is to provide a heat dissipation fan which can dissipate internal heat generated by the heat dissipating fan.

[0007] 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.

[0008] 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:

[0014] Referring to FIG. 1 and FIG. 2, a heat dissipation fan includes a motor and a fan frame 3. The motor comprises a rotor 1 and a stator 2.

[0015] The rotor 1 comprises a hub 10 having a circular top wall and a circumferential wall depending from the top wall. The hub 10 comprises a central shaft 12 and a set of blades 11 extending radially outward from the shaft 12. A permanent magnet 104 is attached to an inner surface of the circumferential wall of the hub 10. A plurality of splaced slots 102 is defined through the top wall of the hub 10 over the permanent magnet 104. The slots 102 are located at an concentric circle and elongated in the circumferential direction of the circle for facilitating an auxiliary tool to enter into the hub 10 from above the hub 10. The permanent magnet 104 is mounted in the hub 10 from the bottom of the hub 10 by means of the auxiliary tool (not shown) that extends through the slots 102 to locate the permanent magnet 104 in the hub 10. Thus, an acceptable precision is achieved.

[0016] The stator comprises a core 20, a coil 22 and a circuit board 24 having a circuit to control the motor.

[0017] The fan frame 3 is formed from a plastic material, and comprises a pedestal 30 and a cylindrical wall 32 extending upwardly from the edge of the pedestal 30. The pedestal 30 comprises a bearing seat 36. The bearing seat 36 comprises a base 361 and a central tube 362 extending upwardly from the top surface of the base 361. Slots 360 corresponding to the slots 102 of the hub 10 are defined in the base 361 beneath the hub 10.

[0018] Referring to FIGS. 3-5, the stator 2 is mounted on the outer periphery of the bearing seat 36. The shaft 12 of the rotor 1 is inserted in the central tube 362 and the permanent magnet surrounds and confronts the stator 2. The slots 360 of the fan frame 3 align with the corresponding slots 102 of the hub 10. When the heat dissipation fan is in operation, the coil 20 is electrified to generate magnetic field which interacts with the permanent magnet 104 of the rotor 1 to drive the rotor 1 to rotate. Ambient air is forced into the hub 10 via the slots 102 and out of the hub 10 via the slots 360. Internal heat generated by the stator 2 is carried away by the ambient air.

[0019] In the heat dissipation fan described above, when any components of the rotor 1 other than the permanent magnet 104 is damaged, the permanent magnet 104 can be easily pushed out of the hub 10 by a tool that extends through the slots 102 of the hub 10 so that the permanent magnet 104 is recycled and the cost is saved.

[0020] 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.