Heat dissipation device

A heat dissipation device includes a canister filled with a phase-changeable working fluid, a housing hermetically fixed to a top of the canister and communicating with the canister, a fan located above a top of the housing and an impeller comprising a driving member received in the housing, an annular magnet accommodated in the hub and an axle coaxially connecting the driving member and the annular magnet together. The fan includes a plurality of windings fixed on an inner side thereof. When the working fluid is heated and vaporized to move through the driving member, the driving member is driven by the vaporized working fluid to rotate, whereby the annular magnet rotates within the windings to cause the windings to generate a current.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a heat dissipation device, and more particularly to a heat dissipation device utilizing a self-circulated fluid system.

2. Description of Related Art

Heat sinks usually remove heat from electronic heat-generating components, such as central processing units (CPUs) etc., to keep the components in stable operation. A typical heat sink comprises a base contacting the heat-generating component to absorb heat therefrom and a plurality of parallel planar fins soldered or adhered to the base. The fins dissipate the heat into ambient atmosphere. To enhance efficiency, a fan is usually mounted on a top or a side of the heat sink to impel air between the fins.

Conventionally, heat generated by the electronic heat-generating components is dissipated directly into the environment via the heat sink, raising the temperature of the surrounding environment rendering the overall system potentially susceptible to damage, thereby shortening the lifespan thereof. Furthermore, heat transfer from the electronic heat-generating components to the surrounding atmosphere without any reasonable recycling component constitutes energy waste.

What is needed is a heat dissipation device capable of recycling heat energy radiated by a heat-generating component, thereby overcoming the described limitations.

SUMMARY OF THE INVENTION

The present invention relates to a heat dissipation device for dissipating heat from a heat-generating electronic element, includes a canister filled with a phase-changeable working fluid and receiving heat from the heat-generating electronic component, a housing, a fan, an impeller. The housing is hermetically fixed to a top of the canister and communicates with the canister. The fan located above a top of the housing, includes a plurality of windings fixed to an inside of the fan. The impeller consists of a driving member received in the housing, an annular magnet accommodated in the inside of the fan and surrounded by the windings and an axle coaxially connecting the driving member and the annular magnet together. The fan includes a hub having an opening facing the housing and a plurality of blades extending outwardly from a circumference of the hub. The axle has a lower end extending downwardly through a bottom of the housing to a center of the top of the canister and an upper end extending upwardly through a top of the housing. When the working fluid is heated by the heat-generating electronic element and vaporized to move into the housing and through the driving member, the driving member is driven by the working fluid to rotate. The annular magnet is rotated accordingly within the windings, whereby the windings are induced by the annular magnet to generate a current therein.

DETAILED DESCRIPTION OF THE INVENTION

Referring toFIGS. 1 to 3, a heat dissipation device in accordance with a preferred embodiment of the invention removes heat from a heat-generating component62mounted on a printed circuit board60. The heat dissipation device comprises a heat conductive member10, a fin unit20attached to the conductive member10, an impeller30mounted on a top of the conductive member10, a housing40fixed to the top of the conductive member10and receiving a lower portion of the impeller30therein and a fan50located on a top of the housing40and interacting with an upper portion of the impeller30.

The conductive member10comprises a base plate12and a canister14vertically mounted on a top of the base plate12. The base plate12is a rectangular flat plate, with a bottom surface contacting the heat generating component62and defining four mounting holes120in four corners thereof to install the heat dissipation device onto the heat-generating component62. The canister14acts as a vapor chamber and includes a metal casing of highly thermally conductive material, such as copper or copper alloy, a phase-changeable working fluid contained in the casing and a capillary wick arranged on an inner surface of the casing. The canister14at a top thereof has a top plate140which defines a circular bay142in a center of a top surface thereof. The top plate140defines a plurality of curved vents144therein, extending along and near a rim of the top plate140and being symmetrical with each other relative to the bay142.

The fin unit20comprises a plurality of fins22attached to a periphery of the canister14and extending radially and outwardly from the periphery of the canister14. The fins22are rectangular flakes, symmetrical with each other relative to an axis of the canister14and have flanges220bent perpendicularly from inner side edges thereof. The flanges220are securely fixed to the periphery of the canister14by soldering.

The impeller30comprises a driving member32, an annular magnet34above the driving member32, and an axle36coaxially extending through a center of the driving member32and the annular magnet34. The driving member32, separated from and located under the annular magnet34, is received in the housing40and has a plurality of blades320formed at a circumference thereof. The annular magnet34secured to the axle36is located above a top of the housing40. The axle36has a lower end projecting downwardly from a bottom of the driving member32for being inserted into the bay142in the top plate140of the canister14, and an upper end projecting upwardly beyond a top of the annular magnet34for engaging with the fan50.

Referring toFIG. 2andFIG. 4, the housing40is cylindrical and has a caliber identical to that of the canister14. The housing40has a top panel42and a bottom panel44parallel and opposite thereto. The top panel42is located between the driving member32and the annular magnet34of the impeller30and defines a through hole420in a center thereof, providing a passage for upward extension of the upper end of the axle36of the impeller30. The bottom panel44is attached to a top surface of the top plate140of the canister14and defines a through hole440(shown inFIG. 3) in the center thereof for downward extension of the lower end of the axle36therethrough into the bay142of the top plate140. The bottom panel44therein defines a plurality of vents444identical to and respectively communicating with the vents144of the top plate140of the canister14.

Referring toFIGS. 2-3, the fan50comprises a hub52, a plurality of blades522extending outwardly from a circumference thereof and a plurality of windings54for having an electromagnetic interaction with the annular magnet34. The windings54are formed by winding copper wires. The hub52has a caliber slightly smaller than that of the housing40and an opening524facing the housing40and receiving the annular magnet34therein. The hub52defines a positioning hole520in a center of a top surface thereof for receiving the upper end of the axle36of the impeller30therein. The windings54are mounted to an inner sidewall of the hub32, symmetrical with each other and closely surround the annular magnet34of the impeller30.

Particularly referring toFIG. 4, in assembly of the heat dissipation device, a bottom surface of the bottom panel44of the housing40is hermetically attached to a top surface of the top plate140of the canister14with the vents144,444communicating with each other. The through hole440is aligned with the bay142. The driving member32of the impeller30is sealed in the housing40, while the annular magnet34of the impeller30located over the housing40is accommodated in the hub52of the fan50and closely surrounded by the windings54of the hub52. The lower end of the axle36is positioned in the bay142of the top plate140of the canister14and the upper end of the axle36is positioned in the positioning hole520of the fan50.

In use of the heat dissipation device, the working fluid in the canister14is heated by the heat-generating component62contacting a bottom surface of the base plate12below the canister14and vaporized. As a result of increased air pressure in the canister14as the working fluid vaporizes, the working fluid in vapor form moves toward and through the vents144,444of the top plate140of the canister14and the bottom panel44of the housing40and then reaches the blades320of the driving member32. The vaporized flow of the working fluid flows through and rotates the blades320of the driving member32, and the annular magnet34securely mounted on the axle36of the impeller30is correspondingly rotated synchronously with the driving member32. Thus, the annular magnet34rotates within the windings54. According to Faraday's law of induction, the rotating annular magnet34induces the windings54to produce an electronic current therein. In addition, the working fluid in vapor form condenses to liquid form when hitting on the blades320of the driving member32, and is then wicked back to a lower portion of the canister14via capillary action in the canister14to resume the circulation.