Patent Application
20070095509
1. Field of the Invention
The present invention relates generally to a heat dissipation device, and more particularly to a heat dissipation device using heat pipes for enhancing heat removal from heat-generating components.
2. Related Art
As computer technology continues to advance, electronic components such as central processing units (CPUs) of computers are being made to provide faster operational speeds and greater functional capabilities. When a CPU operates at high speed in a computer enclosure, its temperature can increase greatly. It is desirable to dissipate the heat quickly, for example by using a heat dissipation device attached to the CPU in the enclosure. This allows the CPU and other electronic components in the enclosure to function within their normal operating temperature ranges, thereby assuring the quality of data management, storage and transfer.
A conventional heat dissipation device comprises a heat sink and a heat pipe. The heat sink comprises a base and a plurality of fins extending from the base. The base defines a groove in the top surface thereof, and bottom surface of the base is attached to an electronic component. Each heat pipe has an evaporating portion accommodated in the groove and a condensing portion inserted in the fins. The base absorbs heat produced by the electronic component and transfers the heat directly to the fins through the heat pipe. By the provision of the heat pipe, heat dissipation efficiency of the heat dissipation device is improved.
In order to further improve the heat dissipation efficiency, it is an efficient way to increase the number of the heat pipe such as two or more. However, it will increase the cost of the heat dissipation device using more heat pipes, and the conventional heat dissipation device has low ratio of performance to cost.
What is needed is a heat dissipation device with a heat pipe which has a high ratio of performance to cost.
A heat dissipation device in accordance with a preferred embodiment of the present invention comprises a heat sink and a heat pipe. The heat sink comprises a base, a fins group extending from the base, and a cover contacting with the fins group. The heat pipe surrounds the fins group and thermally connects with the base and the cover. The heat pipe has a generally rectangular shape with two juxtaposed free end portions sandwiched between the base and the fins group, a top portion parallel to the free end portions and sandwiched between the cover and the fins group, and two connecting portions interconnecting two ends of the top portion and the free end portions, respectively. The free end portions are constructed as an evaporator for the heat pipe, and the top portion is constructed as a condenser for the heat pipe.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:
Referring also to
The heat pipe 20 has a rectangular shape and surrounds the top and bottom faces and two sides of the fins group 16. Referring to
In operation of the heat dissipation device of the preferred embodiment, the base 12 absorbs the heat from the electronic component and a major part of the heat is directly transferred to the free end portions 202, 204 of the heat pipe 20. The free end portions 202, 204 are evaporating portions of the heat pipe 20. A minor part of the heat is conducted upwardly to the fins 160 via a soldering connection between the fins 160 and the base 12. The major part of the heat received by the heat pipe 20 causes liquid in the free end portions 202, 204 thereof to evaporate into vapor. The vapor flows upwardly along the two connecting portions 208 simultaneously. Then the vapor is condensed into liquid in the top portion 206 (which is a condensing portion of the heat pipe 20). The condensed liquid returns to the free end portions 202, 204 along wick structures in the heat pipe 20. Thus, the major part of the heat is transferred to the cover 14 and the fins 160 to be dissipated into surrounding environment.
In the preferred embodiment, the heat pipe 20 comprises two connecting portions 208 disposed at opposite sides of the fins group 16 and connecting the free end portions 202, 204 and the top portion 206. The heat pipe 20 can thereby transfer the heat from the base 12 to the cover 14 along the two connecting portions 208 simultaneously, whereby the heat dissipation efficiency of the heat pipe 20 is the same as using two U-shaped heat pipes. Furthermore, the cost of two U-shaped heat pipes is much more than that of the one heat pipe 20. Therefore, the heat dissipation device of the present invention has a better ratio regarding performance to cost. In an alternative embodiment, the cover can be used to contact with the electronic component. For this, the top portion 206 is constructed as an evaporator and the free end portions 202, 204 are constructed as condensers for the heat pipe 20.
It is understood that the invention may be embodied in other forms without departing from the spirit thereof. Thus, the present examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.
