Heat dissipation device

A heat dissipation device includes a seat, a fin set arranged on the seat, a fan, a fan mounting device having the fan mounted thereto, and a cover covering the fin set. The fan has a portion thereof located above the fin set. An opening is defined in fan mounting device and communicates the fan with the fin set and the fan with a space above a top of the fin set. The cover has a rearwards expanding port for guiding an airflow generated by a system fan to flow through the fin set. A top wall of the cover has a void to expose a portion of the top of the fin set.

FIELD OF THE INVENTION

The present invention relates generally to a heat dissipation device, and more particularly to a heat dissipation device incorporating with a fan for dissipating heat generated by an electronic device.

DESCRIPTION OF RELATED ART

It is well known that, during operation of a computer, electronic devices such as central processing units (CPUs) frequently generate large amounts of heat. The heat must be quickly removed from the electronic device to prevent it from becoming unstable or being damaged. Typically, a heat dissipation device is attached to an outer surface of the electronic device to absorb heat from the electronic device. The heat absorbed by the heat dissipation device is then dissipated to ambient air.

Generally, the heat dissipation device mainly comprises a heat conducting base and a plurality of heat dissipating fins extending from one face of the base. In use, the base has a face opposite the fins attached to the electronic device to absorb the heat generated by the electronic device; then, the heat reaches the fins to be dissipated to the ambient air.

With the development of computer industry, electronic devices of the computer have more and more powerful capacity. Consequently, more and more heat is produced by the electronic devices. The aforementioned heat dissipation device can no longer duly remove the heat from the electronic device; as a result, the heat accumulates in the electronic device and the heat dissipation device, which produces adverse impact to the function of the electronic device. For enhancing the heat dissipation efficiency of the heat dissipation device, a fan is typically desired to be combined thereto to provide a forced airflow to the fins of the heat dissipation device. However, the speedy upgrading trend in computer industry causes electronic devices to become more integrated and powerful, which results in more heat produced by the electronic devices. And more and more electronic devices need heat dissipation. Furthermore, a height of the computer is required to be smaller and smaller. Therefore, the heat dissipation device needs further improvement to meet the demand of heat dissipation of the electronic devices in the computer.

What is needed, therefore, is a heat dissipation device which has great heat dissipating capacity for heat generating electronic devices.

SUMMARY OF INVENTION

A heat dissipation device in accordance with a preferred embodiment of the present invention comprises a seat, a fin set arranged on the seat, a fan located at a front side the fin set, a fan mounting device having the fan mounted thereto, and a cover covering the fin set. The seat has a first face and a second face for contacting with a heat generating device. The fin set comprises a plurality of fins arranged on the first face of the seat, and a plurality of passages being defined between the fins. The fan has a portion thereof located above the fin set. The fan mounting device is located between the fin set and the fan, and comprises a hood hooding a front end of the fin set, and a faceplate having the fan mounted thereto. An opening is defined in the faceplate and communicates the fan with the fin set. The cover has an expanding port defined at a rear end of the fin set for guiding an airflow generated by a system fan to flow through the fin set.

DETAILED DESCRIPTION

Referring toFIG. 1, a heat dissipation device in accordance with a preferred embodiment of the present invention is used for dissipating heat generated by electronic devices (not shown) in a computer enclosure (not show). The heat dissipation device comprises a heat conducting seat10, a first fin set30, a second fin set50, a fan mounting device70, a fan80for providing a forced airflow through the first and second fin sets30,50, and a cover90for guiding the airflow to the first and second fin sets30,50.

Referring also toFIG. 5, the seat10comprises a first base plate11and a second base plate12. The first base plate11has a bottom face defining a recess (not labeled) therein, and a top face for positioning the first and second fin sets30,50thereon. The second base plate12is embedded in the recess of the first base plate11. The first and second base plates11,12cooperatively define two channels (not labeled) therebetween. The first base plate11has an edge defining two cutouts111corresponding to the two channels respectively. Two fixing holes113are defined at a lateral side of the first base plate11for fixing the fan mounting device70thereto. Two L-shaped heat pipes20have first heat transferring sections (i.e., evaporating sections)21received in the two channels respectively, and second heat transferring sections (i.e., condensing sections)22projecting upwardly away from the seat10and through the two cutouts111respectively. A bottom face of the second base plate12is used for contacting with a major one of the heat generating electronic devices such as a central processing unit (CPU).

The first fin set30comprises a plurality of vertical first fins31and a plurality of vertical second fins32assembled together. Each of the first and second fins31,32has a body311,321, and two flanges313,323extending from top and bottom edges of the body311,321. The first fins31are located at two lateral sides of the second fins32and are shorter than the second fins32. The second fins32have a front end (not labeled) projecting forwardly beyond a front end of the first fins31. The first fin set30has a depression33transversely extending in a top face thereof, near the front ends of the first and second fins31,32. A plurality of air passages (not labeled) is defined between the first fins31and the second fins32.

The second fin set50comprises a plurality of horizontal fins51stacked together. Each of the fins51comprises a body511and four locking portions513formed at four corners of the body511, respectively. The locking portions513lock up adjacent fins51together. A bottom one of the fins51has two flaps515extending outwardly. Two vertical through holes517are defined in the bodies511of the fins51, for receiving the condensing sections22of the two heat pipes20. A plurality of air passages (not labeled) is defined between the fins51.

Referring also toFIG. 3, the first fin set30is positioned on the seat10with the bottom flanges313,323thereof soldered to the top face of the first base plate11of the seat10. The second fin set50is stacked on the two condensing sections22of the two heat pipes20with the two condensing sections22being soldered in the two through holes517of the second fin set50.

Referring also toFIGS. 1 and 2, the fan mounting device70is located in front of the first, second fin sets30,50. The mounting device70comprises a hood710for hooding front ends of the first, second fin sets30,50, and a faceplate730formed on the hood710for fixing the fan70thereto. The hood710includes three interconnected walls: two opposite lateral walls711and a top wall713interconnecting the two lateral walls711. The two lateral walls711have corresponding portions (not labeled) slanting toward each other to connect with the faceplate730; therefore, the hood710defines an increasingly expanded channel from the faceplate730rearwards towards the fin sets30,50. The top wall713forms a downwardly extending positioning rib714at a rear end thereof for fitting into the depression33of the first fin set30. The faceplate730is substantially rectangular plate with an opening731defined in a center thereof. The faceplate730and the opening731each have an upper portion located above the top wall713of the hood710. Four fixing holes733are respectively defined at four corners of the faceplate730for fixing the fan90thereto. From bottoms of the slantwise portions of the lateral walls711of the hood710, two fixing tabs715(FIG. 1) each with a fixing hole717defined therein extend downwardly. The fixing holes717are correspondent to the fixing holes113of the first base plate11of the seat10.

Referring back toFIG. 1, the fan80has a square configuration, and comprises a fan bracket81and an impeller83mounted in the bracket81. The bracket81has each corner thereof defining a through hole (not labeled) corresponding to the fixing hole733of the faceplate730of the mounting device70. Four screws (not labeled) are used to extend through the through holes of the bracket81and screw into the fixing holes733to secure to the fan80to the fan mounting device70.

The heat dissipation device further comprises a cover90for covering the first and second fin sets30,50. The cover90comprises a ceiling91and first and second sidewalls93,95depending from two opposite sides of the ceiling91, respectively. The ceiling91is substantially L-shaped from a top aspect thereof. The ceiling91has an indentation911defined at a rear corner thereof adjacent the first sidewall93. A large void913is defined in a front side of the ceiling91near the second sidewall95. The first sidewall93has a flared-out guiding plate931at a rear end thereof.

Referring also toFIGS. 3 and 4, the fan mounting device70has the hood710thereof hooding the front ends of the first and second fin sets30,50. The rib714of the top wall713of the hood710is positioned in the depressions33of the first fin set30. The fan mounting device70is mounted to the seat10via two screws (not labeled) extending through the fixing holes717of the fixing tabs715of the fan mounting device70and screwing in the fixing holes113of the first base plate11of the seat10.

The fan80is mounted to the fan mounting device70via the four screws engaging in the fixing holes733of the faceplate730of the fan mounting device70. When mounted, the fan80alignedly faces the front end of the second fins32of the first fin set30, and has an upper portion thereof located above the top of the first fin set30. The opening731of the fan mounting device70communicates the fan80with the first fin set30, and the upper portion of the opening731is located above the top of the first fin set30(best seen inFIG. 3).

Moreover, an elastic pad85is sandwiched between the fan80and the faceplate730of the fan mounting device70. A configuration of the pad85is substantially similar to that of the faceplate730. The elastic pad85is used to achieve a tight connection between the fan80and the fan mounting device70and to reduce a noise made by operation of the fan80.

The cover90covers on the first and second fin sets30,50, wherein the ceiling91rests on tops of the first and second fin sets30,50. A portion of the top of the first fin set30is exposed to ambient air via the void913of the cover90. Front edges of the ceiling91, the first and second sidewalls93,95abut rear edges of the top and lateral walls713,711of the hood710of the fan mounting device70. The first and second sidewalls93,95are positioned at lateral sides of the second fin set50and the first fin set30, respectively. Rear ends of the ceiling91, first sidewall93and second sidewall95are located behind rear ends of the first and second fin sets30,50, and cooperate with the guiding plate931to define a rearwards expanding port (not labeled) at the rear end of the first and second fin sets30,50for guiding an airflow generated by a computer system fan to flow through the first and second fin sets30,50.

In the present invention, at least a computer system fan (not shown) is located in the expanding port of the heat dissipation device for providing a forced airflow (as shown by arrows inFIG. 5) to flow through the first and second fin sets30,50through an guidance of the guiding plate931.

In use, the bottom face of the second base plate12contacts the CPU to absorb heat from the CPU. The heat in the second base plate12has a portion transferred to the second fin set50through the heat pipes20, and another portion transferred to the first fin set30via the first base plate11. The computer system fan at the expanding port of the heat dissipation device blows the airflow to the first and second fin sets30,50. The fan80facing the first fin set30generates an airflow drawing the heat from the first and second fin sets30,50. Under the action of the fan80, the computer system fan, and the guidance of the cover90and fan mounting device70, cooling air enters the expanding port to flow through the first and second fin sets30,50. The heat in the fins31,32,51is taken away by the cooling air.

According to the preferred embodiment of the present invention, the heat dissipation device has the fan80, the fan mounting device70and the cover90cooperating with each other to guide a strong forced cooling airflow through the first and second fin sets30,50to remove the heat in the fins31,32,51, which is absorbed from the CPU effectively.

The heat dissipation device has two fin set30,50to dissipate heat generated by the electronic device; thus, the heat dissipation device has large heat dissipating area to dissipate heat from the electronic device.

Additionally, the elastic pad85is sandwiched between the fan80and the fan mounting device70, which effectively reduces vibration and thus noise resulting from the operation of the fan80.

Furthermore, the fan80has the upper portion thereof located above the top of the first fin set30; therefore, when the fan80works, the forced airflow produced by the fan80can flow through not only the passages in the first and second fin sets30,50, but also a space above the top of the first fin set30, thereby cooling a second electronic component located on the top of the first fin set30, which in the preferred embodiment is a hard disc (not shown) of the computer. Furthermore, since the top of the first fin set30has an exposed portion through the void913of the ceiling91, the airflow flowing in the passages of the first fin set30can move upwardly through the void913to cool the hard disc.