Patent Application
20090059524
1. Field of the Invention
The present invention relates generally to a heat dissipation device, and more particularly to a heat dissipation device having high heat dissipation efficiency.
2. Description of Related Art
It is well known that during operation computer electronic components such as central processing units (CPUs) can generate large amounts of heat. The heat must be quickly removed from an electronic component to prevent it from becoming unstable or being damaged. Typically, a heat sink is attached to an outer surface of the electronic component to absorb heat generated by the electronic component, and the heat absorbed by the heat sink is then dissipated to ambient air.
As the operation speed of the electronic component becomes faster, the heat generated by the electronic component increases to a point where a conventional heat sink is inadequate. In this case, the heat sink needs to be larger to dissipate heat therefrom, but a size of a computer becomes smaller. Thus, a mount of heat generated by the electronic component is accumulated in the computer.
What is needed, therefore, is a heat dissipation device which has a high heat dissipation efficiency to dissipate heat generated by an electronic component.
A heat dissipation device includes a vapor chamber, a heat sink and a heat pipe. The heat sink includes a plurality of fins. The heat pipe includes an evaporating portion sandwiched between the vapor chamber and the fins of the heat sink, and a condensing portion extending through the fins of the heat sink. The vapor chamber is attached to an electronic component mounted on an add-on card. The fins of the heat sink directly contact with the vapor chamber and define a recess at a bottom thereof to receive the vapor chamber therein.
Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which:
Many aspects of the present apparatus can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present apparatus and method. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
The heat sink 10 is located on the vapor chamber 20 and comprises a plurality of parallel fins 12, a fan 14 and a cover 16 mounted onto the fins 12 and covering the fan 14. The fins 12 comprise two shoulders 121, 123 extending upwardly from the opposite ends thereof and a depressed portion 125 located between the shoulders 121, 123. The fan 14 is mounted on the depressed portion 125 of the fins 12. Two flanges (not labeled) perpendicularly extend from the shoulders 121, 123 of each of the fins 12 to contact each other at uniform intervals. The shoulder 123 is cut away at a lower portion at rear end thereof to define a cutout 1232 to prevent the fins 12 from interfering with other electronic components (not labeled) mounted on the graphics card 40. Two channels 1210 are respectively defined at top portions (not labeled) of the shoulders 121, 123 to receive the heat pipes 30. A recess 127 is defined at a bottom surface of the fins 12 to receive and intimate contact with the vapor chamber 20 so as to transfer heat from the vapor chamber 20 to the fins 12. Two adjoining rectangular grooves 1270 are defined at a center of the bottom surface of the fins 12 to receive the heat pipes 30.
Referring to
The vapor chamber 20 is attached on the electronic component 42 and mounted on the graphics card 40 to absorb heat generated from the electronic component 42. The vapor chamber 20 has a flat type configuration and is rectangular shaped when viewed from above. The vapor chamber 20 comprises a rectangular shaped base plate 21, a top cover 23 on an opposite side of the vapor chamber 20 to the bottom plate 21. The base plate 21 and the top cover 23 are made of the materials having high thermal conductive capabilities, such as copper. The top cover 23 comprises a flat cover plate 231 parallel to the base plate 21 and four sidewalls 233 perpendicularly and downwardly extending from a periphery of the cover plate 231 and soldered to the base plate 21. Four counterbores 27 are defined in four corners of the vapor chamber 20, respectively, corresponding to the through holes 44 of the graphics card 40. Each counterbore 27 defines a first through hole (not labeled) in the top cover 23 and a smaller second though hole in the base plate 21. The top cover 23 downardly extends a respective annular sidewall (not labeled) surrounding each first through hole thereof. The vapor chamber 20 is enclosed to form a sealed cavity. Wick structures (not shown) are formed in the sealed vapor chamber 20 and work fluid (not shown) is contained in the vapor chamber 20. The vapor chamber 20 comprises a plurality of supporting posts (not shown) therein for supporting the top cover 23. The top cover 23 is located at the center of the bottom plate 21 and a flange 25 is formed between each side of the top cover 23 and the base plate 21. The vapor chamber 20 has a heating area (not labeled) contacting with the electronic component 42 mounted on the graphics card 40 and a cooling area (not labeled) except the heating area. The heating area absorbs the heat generated by the electronic component 42 and the cooling area transfers the heat to the fins 12 of the heat sink 10 and dissipates the heat into environment.
Each of the heat pipes 30 has a U-shaped configuration and comprises a flattened evaporating portion 32, a condensing portion 34 and an arc connecting portion 36 connecting with the evaporating portion 32 and the condensing portion 34. The flattened evaporating portion 32 has a flattened top plate and a bottom plate on an opposite side of the evaporating portion 32 to the top plate 161. The condensing portions 34 extend through the shoulders 121, 123 and are received in the channels 1210 of the heat sink 10; the evaporating portions 32 are received in the rectangular grooves 1270 and coplanar with the bottom surface of the fins 12.
The electronic assembly further comprises a back plate 50 for reinforcing the graphics card 40. The back plate 50 is positioned below a bottom side of the graphics card 40. The back plate 50 is cross-shaped and defines four through holes 52 therein and has four nuts 60.
Referring to
In use of the heat dissipation device 100, the working fluid contained in the vapor chamber 20 moves from the heating area to the cooling area with a phase transition, i.e., from a liquid phase to a vapor phase, due to the heat absorbed from the electronic component 42. The vapor moves vertically upwardly to transfer the heat to the heat sink 10 via the cover plate 231 of the vapor chamber 20. Furthermore, the vapor moves horizontally to transfer the heat to the cooling area of the vapor chamber 10. The heat is therefore directly dissipated to the surrounding environment of the vapor chamber 20 and evenly transferred to the heat sink 10 at the top thereof, which further dissipates the heat to the surrounding environment. The heat pipes 30 transfer the heat to the heat sink 10. The fan 14 received in the cavity defined by the shoulders 121, 123 and the baffle plates 163, 165 directs airflow onto the heat sink 10 to reinforce heat dissipation efficiency of the heat dissipation device 100. Thus, the heat generated by the electronic component 42 is dissipated quickly.
It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereto described merely being preferred or exemplary embodiments of the invention.
