BRIEF DESCRIPTION OF THE DRAWINGS
The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:
FIG. 1 is a sectional view of a conventional fan.
FIG. 2 is a sectional view of an embodiment of the heat dissipating fan of the invention.
FIG. 3A is an exploded view of another embodiment of the heat dissipating fan of the invention.
FIG. 3B is a side view of the first rotor of the heat dissipating fan of FIG. 3A.
FIG. 3C is a top view of the first rotor of the heat dissipating fan of FIG. 3A.
FIGS. 4A and 4B are schematic diagrams showing various types of the heat dissipating holes of the heat dissipating fan of FIG. 3A.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 shows an embodiment of the heat dissipating fan of the invention. The heat dissipating fan includes, a frame 21, a base 22 disposed in the frame, a plurality of ribs 23 disposed between the base 22 and the frame 21, a first rotor 24, a driving element (e.g. motor) 25 disposed in the base and supported by the base 22, a shaft 26, and a second rotor 27 disposed at the rear (i.e. leeward side) of the first rotor 24. The shaft 26 is an end passing through a top of a hub 271 of the second rotor 27 to be fixed thereto. The hub 271 of the second rotor 27 is hollow and shaped like a cup. The ribs 23 in the frame 21 can be replaced by stationary vanes to increase the work capacity of the second rotor 27, thereby increasing airflow pressure. Preferably, tails of the stationary vanes 23 extend vertically to increase the work capacity of the second rotor 27. The shaft 26 is fixed to the second rotor 27 via riveting, screwing, gluing or similar ways. Thus, the driving element 25 drives the first rotor 24 and the second rotor 27 simultaneously via the shaft 26 at the same speed. The number of vanes of the first rotor 24 is different from that of the second rotor 27. For example, the first rotor 24 has eight vanes and the second rotor 27 has nine vanes to reduce noise.
The first rotor 24 and the second rotor 27 respectively have a plurality of heat dissipation holes 242 and 272 at the tops of their hubs. When the first rotor 24 and the second rotor 27 rotate via the driving element 25, airflow passes through the heat dissipating holes 242 and 272 of the hubs of the first rotor 24 and the second rotor 27 for dissipating heat produced by the driving element 25 so as to prolong the life of the driving element 25. The vanes of the first rotor 24 are extended upward at an inclined angle, and the frame 21 has an expanding portion 211 at an end thereof for collecting more airflow.
FIGS. 3A to 3C show another embodiment of the heat dissipating fan of the invention. The structures illustrated in FIGS. 3A to 3C are similar to the previously described embodiment expect that a top surface of the hub of the first rotor 24 is cone-shaped, leaf-hat-shaped or inclined and the hubs have inclined inner walls in the heat dissipating holes 242 and 272. The heat dissipating fan further includes a first air-guiding shroud 3 and a second air-guiding shroud 4 disposed respectively on opposite sides of the frame 21. Additionally, the second air-guiding shroud 4 includes a plurality of internal stationary vanes 41 for increasing the pressure of airflow passing through the vanes. Thus, the heat dissipation is effectively increased. The first air-guiding shroud 3 can also have a plurality of internal stationary vanes. The first air-guiding shroud 3 and the second air-guiding shroud 4 are preferably expanded at the edges or bell-shaped. The first air-guiding shroud 3 and the second air-guiding shroud 4 are connected to the frame 21 via engaging, riveting, screw, gluing or similar ways. The frame 21 includes a plurality of ears for fixing the heat dissipation fan to the casing of an external system.
The heat dissipating holes on the hub of the first rotor or the second rotor are wing-shaped or flat plat-shaped. From FIGS. 4A to 4B, when the motor rotates the rotor, the vans of the first and second rotors generate airflow and forced convection is produced via the wing-shaped or flat plate-shaped holes in the hub area. The airflow dissipates heat generated by the motor.
As described above, the invention provides a small and powerful heat dissipating fan in which several rotors are driven via a single high-efficiency driving element (or motor). In addition, a plurality of heat dissipating holes are provided in the rotor such that airflow enters via the heat dissipating holes of the front rotor and exits via the heat dissipating holes in the back of the rotor to overcome high resistance in the motor. When the motor consumes power of more than 100 W, the rotor of the invention reduces the operating temperature by about 20 degrees. Thus, the invention efficiently dissipates waste heat produced from the wire windings of a high-efficiency motor, increases airflow passing through the motor, increases heat convection efficiency, and reduces temperature of the motor, thereby protecting the motor and extending product life.
While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
Patent Application
20070284955
