Heat dissipation device   

This application is related to U.S. patent application Ser. No. 11/308,852 filed on May 15, 2006 and entitled “HEAT PIPE TYPE HEAT DISSIPATION DEVICE”; the co-pending U.S. patent application is assigned to the same assignee as the instant application. The disclosure of the above-identified application is incorporated herein by reference.

1. Field of the Invention

The present invention generally relates to heat dissipation devices, and more particularly to a heat pipe type heat dissipation device for removing heat from a heat-generating electronic component.

2. Description of Related Art

Computer electronic components, such as central processing units (CPUs), generate great amounts of heat during normal operation. If not quickly removed this can deteriorate their operational stability and damage associated electronic equipment. Thus the heat must be removed quickly to ensure normal operation thereof. A heat sink is often attached to a top surface of a CPU to remove heat therefrom.

A conventional heat sink is made of highly heat-conductive metal, such as copper or aluminum, and generally includes a base portion for contacting the electronic component to absorb heat therefrom and a plurality of fins formed on the base portion for dissipating heat. However, as the operating speed of electronic components has been continually upgraded, these kinds of conventional heat sinks can no longer meet the heat dissipation requirements of modern IC packages. In recent years, heat pipes have been widely used due to their great heat-transferring capability. Accordingly, heat sinks equipped with heat pipes come into widespread use.

Conventionally, a heat sink incorporated with heat pipes comprises a base, a plurality of individual fins located above the base and two U-shaped heat pipes thermally connecting the fins and the base together. The fins are spaced from each other, parallel to the base and define corresponding through holes therein. Each of the heat pipes comprises an evaporating section attached to a top surface of the base and two condensing sections extending perpendicularly from two opposite ends of the evaporating section and received in the corresponding through holes of the fins. In use of such type of heat sink, heat generated by the heat-generating component can be absorbed by the base and then transfer to the fins via the heat pipes timely to dissipate into ambient air.

However, the fins are discrete from each other and each of the fins is a thin flake and has flanges extending perpendicularly from edges of the through holes thereof to maximize a contacting area between the heat pipes and the fins, manufacturing of such fins is very expensive and time-consuming. Additionally, combination of the fins and the heat pipes completed by soldering is no so good in reliability that in risk of collapse when last a long time.

What is needed is a improved heat dissipation device can overcome the above problems.

A heat dissipation device for removing heat from a heat generating-component mounted on a printed circuit board includes a heat sink and two heat pipes. The heat sink comprises a base plate kept in contacting with the heat-generating component, two conducting arms extending upwardly and obliquely from two opposite ends of the base plate, a plurality of first fins extending upwardly from top surfaces of the base plate and the two conducting arms, and a plurality of second fins extending downwardly from bottoms surfaces of the conducting arms. The two heat pipes each comprise a evaporating section received in the base plate, at least a condensing section received in one of the conducting arms and at least a connecting section connecting at least an end of the evaporating section and the at least a condensing section.

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:

Referring to FIG. 1 to FIG. 3, a heat dissipation device in accordance with a preferred embodiment of the invention is adapted for dissipating heat from a heat-generating component 42 which is mounted on a printed circuit board 40. The heat dissipation device is cuboid in configuration and comprises a first heat sink 10 having a bottom surface contacting with the heat-generating component 42, a second heat sink 20 disposed on the first heat sink 10 and two tortuous heat pipes 30 sandwiched between the first and second heat sinks 10, 20.

Particularly referring to FIG. 2, the first heat sink 10 integrally formed of a metal with a good heat conductivity such as aluminum, copper and allay, comprises a first plate 12 and a plurality of first fins 14 extending vertically and downwardly from two lateral portions of the first plate 12. The first plate 12 comprises a first horizontal part 122 and two first oblique parts 124 extending obliquely from two opposite ends of the first horizontal part 122. The two first oblique parts 124 are symmetrical to each other relative to a midline of the first horizontal part 122. The horizontal part 122 in a top surface thereof defines two spaced first receiving grooves 1220 that perpendicular to two lateral sides thereof. Each of the oblique parts 124 in a top surface thereof defines two spaced second receiving grooves 1240 that perpendicular to two lateral sides thereof, wherein an outer one of the second receiving grooves 1240 is adjacent to free end of the corresponding first oblique part 124. The first fins 14 are perpendicular to the horizontal part 122 of the first plate 12 and extend vertically from bottom surfaces of the two oblique parts 124 of the first plate 12. Bottom ends of the first fins 14 level with a bottom surface of the first horizontal part 122, it means heights of the first fins 14 increase gradually along two lateral directions from the opposite ends of the horizontal part 122 toward ends of the oblique parts 124.

Particularly referring to FIG. 3, the second heat sink 20 is integrally formed of a metal with a good heat conductivity such as aluminum, copper and allay. The second heat sink 20 is complementary with the first heat sink 10 and comprises a second plate 22 similar to the first plate 12 of the first heat sink 10 and a plurality of second fins 24 extending vertically and upwardly from two lateral portions of the second plate 22. The second plate 22 comprises a second horizontal part 222 and two second oblique parts 224 extending obliquely from two opposite ends of the second horizontal part 222. The two second oblique parts 224 are symmetrical to each other relative to a midline of the second horizontal part 222. The horizontal part 222 in a bottom surface thereof defines two spaced first receiving grooves 2220 that are perpendicular to two lateral sides thereof. Each of the oblique parts 224 in a bottom surface thereof defines two spaced second receiving grooves 2240 that perpendicular to two lateral sides thereof, wherein an outer one of the second receiving grooves 2240 is adjacent to free end of the corresponding second oblique part 224. The first and second receiving grooves 2220, 2240 of the second plate 22 of the second heat sink 20 are corresponding to the first and second receiving grooves 1220, 1240. The second fins 24 are perpendicular to the horizontal part 222 of the second plate 22 and extend vertically from bottom surfaces of the two oblique parts 224 of the second plate 22. Top ends of the second fins 24 level with each other, it means heights of the second fins 24 decrease gradually along two lateral directions from ends of oblique parts 224 to the opposite ends of the horizontal part 222. When the first and second heat sink 10, 20 are assembled together, the first and second plates 12, 22 are combined together to define a base plate; the first and second oblique parts 124, 224 are respectively combined to define two conducting arms; the first and second receiving grooves 2220, 2240 of the second plate 22 of the second heat sink 20 respectively cooperate with the first and second receiving grooves 1220, 1240 of the first plate 12 of the first heat sink 10 to form a first through hole in the base plate and second through holes for receiving the heat pipes 30 in each of the conducting arms.

Each of the heat pipes 30 comprises an evaporating section 32, a first condensing section 34, a first connecting section 33 connecting an end of the evaporating section 32 and the first condensing section 34, a second condensing section 36 parallel to the evaporating section 32, and a second connecting section 35 connecting another end of the evaporating section 32 and the second condensing section 36 together. The first condensing section 34 is located between and parallel to the evaporating section 32 and the second condensing section 36. The first condensing section 34 is more far away from the evaporating section 32 than the second condensing section 36. The first and second connecting sections 33, 35 are parallel to each other and perpendicular to the evaporating section 32.

In assembly of the heat dissipation device, the second heat sink 20 is disposed on the first heat sink 10 and complementary with the first heat sink 10. The two evaporating sections 32 of the two heat pipes 30 are intimately received in the first through holes of the base plate. The first and second condensing sections 34, 36 of each of the heat pipes 30 are intimately received in the second through holes of one of the conducting arm adjacent to the corresponding first through hole. The two connecting sections 33, 35 of each of the heat pipes 30 are exposed out of the first and second heat sinks 10, 20 and located at two lateral sides of one of the two conducting arms.

In use of the heat dissipation device, heat absorbed by the base plate is transferred to the two conducting arms and then distributed to the fins 14, 24 to dissipate into ambient. A thermal conductive capability between the base plate and the two conducting arms is dramatically enhanced, heat accumulated in the base plate is more quickly conducted to the conducting arms and heat dissipation efficiency of the heat dissipation device is thus greatly improved. As contacting area between the first and second heat sink 10, 20 is adequately large, assembly of the first, second heat sink 10, 20 and the heat pipes 30 sandwiched between the first and second heat pipes 30 is more secure and reliable.

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 hereinbefore described merely being preferred or exemplary embodiments of the invention.