Cooling fan

Abstract

A cooling fan includes a frame (100) and an impeller (200) with blades (240) disposed in the frame (100). The frame (100) has a base (140) and a sidewall (160) extending from a periphery of the base (140) with an air outlet (180) defined therein. The base (140) has an air inlet (142) and a vent hole (148) defined therein. The vent hole (148) is near the air outlet (180) and between tip portions of the blades (240) and the sidewall (160). In a preferred embodiment, the base (140) has a supporting portion (144) disposed in the air inlet (142). Two ribs (146) extend from a periphery of the supporting portion (144) towards the base (140). One of the ribs (146) is arranged adjacent to the air outlet (180) and has a changeable width which is gradually increased along a direction from the supporting portion (144) to the base (140).

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates generally to a cooling fan, and more particularly to a cooling fan having low noise.[0003]2. Description of Related Art[0004]The computer CPU speed has been greatly increased in recent years due to a rapid progress in semi-conductor technologies. The chip surface heat flux is thus higher and higher accordingly. It is becoming a critical challenge on how to remove the heat so that the system can run reliably. The compact space with high flow resistance in a notebook computer environment is even more critical in the heat removal. A fan with higher air pressure is frequently chosen under such a consideration.[0005]A fan in related art is shown in FIG. 3. The fan includes a frame 10 and an impeller 20 disposed in the frame 10. The frame 10 includes air inlets 12, 14 matching the impeller 20 and an air outlet. The impeller 20 includes a hub 22, a base plate 24 and a plurality of blades 26 formed...

AI Technical Summary

Benefits of technology

[0007]In accordance with a preferred embodiment of the present invention, a cooling fan comprises a frame and an impeller having a plurality of blades disposed in the frame. The frame has a base and a sidewall extending from a periphery of the base with an air outlet defined therein. The base has an air inlet and a vent hole defined therein. The vent hole is in vicinity of the air outlet and between tip portions of the blades and the sidewall of the frame. In accordance with another preferred embodiment of the present invention, a cooling fan comprises a frame and an impeller having a plurality of blades disposed in the frame. The frame comprises a base and a sidewall extending from a periphery of the base with an air outlet defined therein. The base has an air inlet defined therein, a supporting portion disposed in the air inlet and two ribs extend from a periphery of the supporting portion towards the base so as to connect the supporting portion with the base. One of the ribs is arranged adjacent to the air outlet, and the one of the ribs arranged adjacent to the air outlet has a changeable width which is gradually increased along a direction from the supporting portion to the curved tongue portion.

Problems solved by technology

It is becoming a critical challenge on how to remove the heat so that the system can run reliably.

However, an air outflow in a curved tongue portion 16 of the frame 10 will interfere with the intake airflow of the air inlets 12, 14 and the later air outflow due to adverse airflow, creating many problems such as noise.

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