Heat dissipation apparatus

A heat dissipation apparatus (10) includes a heat-dissipating fan (14) and a fin assembly (12). The heat-dissipating fan includes a casing (141) and a plurality of blades (142) rotatably received in the casing. The casing defines an air outlet (148) through which an airflow generated by the blades flows. The fin assembly is disposed at the air outlet of the fan, and includes a plurality of first fins (121) and a plurality of second fins (122) disposed between the first fins and the blades of the fan. The second fins are so positioned that outer ends of the second fins are oriented toward a far side of the air outlet while inner ends of the second fins are oriented toward a near side of the air outlet. The outer ends of the second fins are located adjacent to the first fins. An airflow generated by the blades first flows to the near side and then to the far side of the air outlet.

FIELD OF THE INVENTION

The present invention relates generally to a heat dissipation apparatus, and more particularly to a heat dissipation apparatus for dissipating heat generated by electronic components.

DESCRIPTION OF RELATED ART

Following the increase in computer processing power that has been seen in recent years, greater emphasis is now being laid on increasing the efficiency and effectiveness of heat dissipation devices. Referring toFIG. 3, a conventional heat dissipation apparatus20includes a heat-dissipating fan22and a fin assembly24disposed at an air outlet221of the heat-dissipating fan22. The fin assembly24includes a plurality of fins242which thermally connect with a heat generating electronic component (not shown) to absorb heat therefrom. The heat-dissipating fan22includes a casing222, a stator (not shown) mounted in the casing222, and a rotor223rotatably disposed around the stator. When the heat-dissipating fan22is activated, the rotor223rotates in a counterclockwise direction around the stator, creating an airflow flowing through the fin assembly24in a manner so as to take away heat therefrom.

In operation of the heat dissipation apparatus20, the casing222guides the airflow to move towards an upper side246of the air outlet221of the heat-dissipating fan22. A portion of the airflow leaves the heat-dissipating fan22at the upper side246of the air outlet221with another portion flowing towards a bottom side244of the fin assembly24from the upper side246thereof. A flow direction of the airflow flowing toward the upper side246of the fin assembly24is substantially parallel to the fins242thereof, while the airflow flowing toward the bottom side244of the fin assembly24forms an acute angle with each fin242of the bottom side244of the fin assembly24. The airflow flowing toward the bottom side244of the fin assembly24may be deflected by the fins242thereof due to the acute angles formed therebetween. This deflection of the airflow may cause a loss in kinetic energy of the airflow. Thus speed of the airflow flowing toward the bottom side244of the fin assembly24may be reduced. The heat dissipation efficiency of the heat dissipation apparatus20will thereby be further reduced. Accordingly, it can be seen that the heat dissipation efficiency of the heat dissipation apparatus20has room for improvement.

SUMMARY OF THE INVENTION

The present invention relates to a heat dissipation apparatus for dissipating heat generated by an electronic component. According to a preferred embodiment of the present invention, the heat dissipation apparatus includes a heat-dissipating fan and a fin assembly. The heat-dissipating fan includes a casing and a plurality of blades rotatably received in the casing. The casing defines an air outlet through which an airflow generated by the blades flows. The fin assembly is disposed in the air outlet of the fan, and includes a plurality of first fins and a plurality of second fins disposed between the first fins and the blades of the fan. The second fins, in relative to the first fins, are so rotated that outer ends of the second fins are moved toward a far side and inner ends of the second fins are moved toward a near side of the air outlet from which the airflow leaves the fan for guiding the airflow to flow more smoothly and evenly through the fin assembly. The airflow generated by the fan first flows to the near side and then to the far side.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIG. 1, a heat dissipation apparatus10according to a preferred embodiment of the present invention is shown. The heat dissipation apparatus10includes a fin assembly12thermally connected with a heat-generating electronic component (not shown) to absorb heat therefrom, and a heat-dissipating fan14for providing an airflow flowing through the fin assembly12to take the heat away.

The heat-dissipating fan14is a centrifugal blower which enables the airflow to have a high air pressure. The heat-dissipating fan14includes a casing141, a stator (not shown) mounted in the casing141, and a rotor including a plurality of blades142rotatably disposed around the stator.

The casing141includes a bottom housing143and a top cover144mounted on the bottom housing143. The top cover144is a plate, which defines a through hole therein functioning as an air inlet145for the heat-dissipating fan14. The bottom housing143includes a flattened base146, and an arc-shaped sidewall147perpendicular to the top cover144and the base146of the bottom housing143. The sidewall147of the bottom housing143defines an arc-shaped opening therein functioning as an air outlet148for the heat-dissipating fan14. An air channel149is formed between free ends of the blades142and an inner surface of the sidewall147of the bottom housing143. A width of the air channel149is gradually increased along a clockwise direction as viewed fromFIG. 2so as to increase the pressure of the airflow, wherein the blades142rotate clockwise. In operation of the heat-dissipating fan14, the airflow is driven to first flow to a right side148bof the air outlet148and then to a left side148athereof, whereby the airflow leaves the air outlet148and the fin assembly12to take heat away from the fin assembly12.

The fin assembly12is arc-shaped in profile to match with the air outlet148of the heat-dissipating fan14. The fin assembly12includes a plurality of outer and medium fins121,122. Each of the outer and medium fins121,122includes a main body123, and two flanges124perpendicularly extending from two opposite ends of the main body123. The outer fins121are disposed at an outer edge of the air outlet148of the heat-dissipating fan14and around a rotational axis of the rotor. The outer fins121are so oriented that they are generally pointed toward the rotational axis of the rotor. The medium fins122are located between the outer fins121and the blades142of the heat-dissipating fan14, with outer ends (air outtakes) thereof contacting with inner ends of the outer fins121. The medium fins122, in relative to the outer fins121, are rotated with an angle so that the outer ends of the medium fins122are moved towards the left side148aof the air outlet148while inner ends (air intakes) of the medium fins122are moved toward the right side148b. The main bodies123of each of the outer and medium fins121,122are linear shaped as viewed fromFIG. 2, and separately form larger and smaller acute angles with the flow direction of the airflow flowing toward the fin assembly12. A plurality of air passages125are formed between adjacent fins121,122, with a linear-shaped portion formed between two adjacent medium fins122facing to the airflow flowing theretoward. During the airflow flowing through the air passages125of the fin assembly12, the flow direction of the airflow is slightly changed to a direction parallel to the main bodies123of the medium fins122, and then is further changed to a direction parallel to the main bodies123of the outer fins121. The flow direction of the airflow is thus gradually and smoothly changed to a direction parallel to the main bodies123of the outer fins121, which makes the airflow flow evenly through the air passages125of the fin assembly12, without being fiercely deflected by the fins242of the fin assembly24of the conventional heat dissipation apparatus20ofFIG. 3.

In the present invention, the main bodies123of the medium fins122of the fin assembly12form smaller angles with the flow direction flowing toward the fin assembly12. The flow direction of the airflow is gradually and smoothly changed to a direction parallel to the main bodies123of the outer fins121. This makes the airflow flow evenly through the air passages125of the fin assembly12. So the airflow arriving at the fin assembly12can not be fiercely deflected by the outer and medium fins121,122of the fin assembly12. The kinetic energy loss from the airflow is thus prevented and the heat dissipation efficiency of the heat dissipation apparatus10is thereby increased.

In the present invention, the fin assembly12consists of two kinds of fins, i.e. the outer fins121and the medium fins122, with acute angles formed between each kind of the fins and the flow direction of the airflow flowing toward the fin assembly12increasing from an inner side of the air outlet148towards the outer side thereof. Alternatively, the fin assembly may consist of more than two kinds of fins, with acute angles formed between each kind of the fins and the flow direction gradually increasing from an inner side of the air outlet toward outer side thereof.