1. Field of Invention
The invention relates to a fan and, in particular, to a centrifugal fan.
2. Related Art
Since the present electronic products are rapidly developed towards high performance, high frequency, high speed and compactness, the generated heat of the electronic products becomes greater. However, the electronic products are unstable in the high temperature, which affects the reliability thereof. Thus, the heat dissipation has become an important issue of the present electronic products.
The fan is a common heat dissipating device for the electronic product. As shown in
When the impeller 11 rotates, airflow enters the center of the impeller 11. Then, the rotated blades 112 force the airflow to radiately flow out of the blades 112. Since the airflow may have the counterflow, backflow, and separation phenomenon in the impeller 11, the flow field after entering the impeller 11 becomes very complicated.
In more details, since the speed of the airflow near the hub 111 is lower than that at other places, the utility efficiency of the airflow near the hub 111 is poor. If this utility efficiency is appropriately enhanced, the performance of the whole fan can be better so as to increase the heat dissipation effect. It is therefore an important subject of the invention to improve the entire working efficiency of the centrifugal fan and the impeller thereof for obtaining higher heat dissipation effect.
In view of the foregoing, the invention is to provide a centrifugal fan and an impeller thereof that can efficiently improve the entire working efficiency for enhancing the heat dissipation effect.
To achieve the above, an impeller of the invention is applied to a centrifugal fan and includes a base plate, a plurality of first blades, and a hub. The first blades are disposed on the base plate with respect to the hub as a center. The hub is connected to the base plate, and has a plurality of second blades disposed around an outer wall of the hub.
To achieve the above, a centrifugal fan of the invention includes an impeller and a motor. The impeller includes a base plate, a hub, and a plurality of first blades. The first blades are disposed on the base plate with respect to the hub as a center. The hub is connected to the base plate, and has a plurality of second blades disposed around an outer wall of the hub. The motor is coupled to the impeller for driving the impeller to rotate.
As mentioned above, the centrifugal fan and impeller of the invention have a plurality of second blades disposed around the outer wall of the hub. Due to the second blades, the utility efficiency of the airflow near the hub can be appropriately enhanced so as to increase the heat dissipation effect. Furthermore, the centrifugal fan of the invention may have the superior performance at a high air pressure area.
The invention will become more fully understood from the detailed description given herein below illustration only, and thus is not limitative of the present invention, and wherein:
The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
The impeller 21 further includes a connecting ring 214, which is connected to a side of the first blades 213 opposite to another side thereof facing the base plate 212. In the embodiment, the connecting ring 214 and the first blades 213 are integrally formed.
With reference to
In these embodiments, the second blades 2111 or 2111′ and the first blades 213 are, but not limited to, forward leaning blades, backward leaning blades, plate blades, or their combinations. The number of the second blades 2111 or 2111′ is not limited and is unnecessary to have an absolute relation with the number of the first blades 213. In addition, the positions of the second blades 2111 or 2111′ are unnecessary to have a relation with the positions of the first blades 213. In conclusion, the shapes and number of the second blades and the relationship between the first and second blades are determined according to the actual needs.
In summary, the centrifugal fan and impeller of the invention have a plurality of second blades disposed around the outer wall of the hub. Due to the second blades, the utility efficiency of the airflow near the hub can be appropriately enhanced so as to increase the heat dissipation effect. Furthermore, the centrifugal fan of the invention may have the superior performance at the high air pressure area.
Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the invention.
Number | Date | Country | Kind |
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094139630 | Nov 2005 | TW | national |