Cooler module   

(a) Field of the Invention

The present invention relates to a cooler module for cooling an electronic chip and more particularly to such a cooler module, which has radiation fins tightly fastened together in a stack by fitting the double-step mounting holes of one radiation fin into corresponding double-step mounting holes of another radiation fin. The engagement among the double-step mounting holes is enhanced when heat pipes are inserted through the double-step mounting holes in a tight manner.

(b) Description of the Prior Art

Heat pipes are intensively used in cooler modules for cooling semiconductor chips or the like. In addition to heat pipes, a cooler module further comprises a heat sink formed of a stack of radiation fins, and a copper or aluminum base block. The radiation fins are extruded from aluminum or copper. The heat pipes are enclosed metal tubes filled with a working fluid. The base block is an aluminum or copper block.

The aforesaid heat pipes have a relatively greater diameter at one end and a relatively smaller diameter at the other end. The tolerance of the diameter is about ±0.05 mm. Therefore, the cross section of the heat pipes is not a true circle. Because of the diameter tolerance of the heat pipes, the heat pipes may not be kept in tight contact with all the radiation fins, thus lowering the structural strength or causing vibration of the radiation fins. During delivery of the cooler module, the radiation fins may be damaged easily. Solder bonding may be employed to reinforce the structural strength. However, this extra processing causes environmental pollution, and greatly complicates the fabrication of the cooler module and increases its cost.

FIG. 8 shows a prior art design, in which each heat pipe mounting hole of each radiation fin 10 has step portion 101. By means of stopping the step portions 101 of the heat pipe mounting holes of one radiation fin 10 against the corresponding step portions 101 of the heat pipe mounting holes of another radiation fin 10, the radiation fins 10 are arranged in a stack. Thereafter, heat pipes 20 are fitted into the heat pipe mounting holes of the radiation fins 10 to enhance the engagement of the step portions 101 of the radiation fins 10. However, because the heat pipes 20 do not have a true roundness, and the diameter of the heat pipes 20 has a tolerance about ±0.05 mm, the heat pipes 20 may not be kept in close contact with the radiation fins 10. Therefore, the radiation fins 10 may be loosened easily, thus lowering the heat dissipation performance of the cooler module.

The present invention has been accomplished under the circumstances in view. According to one aspect of the present invention, the cooler module comprises a plurality of radiation fins, a plurality of heat pipes, a base block, and a thermal pad. The radiation fins each have a plurality of double-step mounting holes, which receive the heat pipes tightly. The double-step mounting holes each have an annular inner step portion and an annular outer step portion. The annular outer step portion of one double-step mounting hole of one radiation fin is tightly fitted into the annular inner step portion of the corresponding double-step mounting hole of another radiation fin so that the radiation fins are tightly fastened together in a stack. The heat pipes are respectively tightly fitted into the double-step mounting holes of the radiation fins to force the annular outer step portions of the double-step mounting holes of the radiation fins against the corresponding annular inner step portions of the double-step mounting holes of the neighboring radiation fins, reinforcing the structural strength and enhancing the heat dissipation effect.

FIG. 1 is an exploded view of a cooler module in accordance with the present invention.

FIG. 2 is an elevational assembled view of the cooler module in accordance with the present invention.

FIG. 3 is a side view of the cooler module in accordance with the present invention.

FIG. 4 is a sectional view of the cooler module in accordance with the present invention, taken along line 4-4 of FIG. 3.

FIG. 5 is an enlarged view of a part of FIG. 4.

FIG. 6 is a schematic drawing showing the fitting of one heat pipe into one double-step mounting hole of each of the radiation fins according to the present invention.

FIG. 7 is an exploded view of a U-turn cooler module.

FIG. 8 is a schematic sectional assembled view of radiation fins and one heat pipe according to the prior art.

Referring to FIG. 1, a cooler module in accordance with a first embodiment of the present invention is shown comprised of a heat sink 1, which is formed of a stack of first radiation fins 11a and second radiation fins 11b, a plurality of heat pipes 2, and a base block 3 (see also FIGS. 2 and 3).

The heat pipes 2 are enclosed metal pipes filled with a working fluid, each having a selected part (an extension (see FIGS. 1 and 2) arm or U-turn (see FIG. 7)) bonded to the base block 3. The base block 3 is a solid metal (copper or aluminum) block tightly fastened with the heat pipes 2. The bottom surface of the base block 3 may be mounted with a thermal pad 4 (by means of rivet or tongue-and-groove joint, or compression bonding technique).

The main feature of the present invention is at the mounting arrangement between the heat sink 1 and the heat pipes 2. The radiation fins 11a or 11b each have a plurality of double-step mounting holes 13 for receiving the heat pipes 2 tightly (see FIGS. 2 through 4). Each double-step mounting hole 13 has an outer step portion 131 and an inner step portion 132 (see FIG. 5), i.e., each double-step mounting hole 13 has two annular steps of different diameters such that the radiation fins 11a and 11b can be firmly arranged in a stack by tightly fitting the outer step portion 131 of each of the double-step mounting holes 13 of one radiation fin 11a or 11b into the inner step portion 132 of one of the double-step mounting holes 13 of another radiation fin 11a or 11b. When the radiation fins 11a and 11b are fastened together, the associated double-step mounting holes 13 form respective through holes into which the heat pipes 2 are tightly fitted.

Referring to FIG. 6, the inner diameter C of the inner step portions 132 of the double-step mounting holes 13 of the radiation fins 11a and 11b is slightly smaller than the outer diameter A of the outer step portions 131 of the double-step mounting holes 13 of the radiation fins 11a and 11b.

Therefore, the double-step mounting holes 13 of one radiation fin 11a or 11b can be tightly fitted into the double-step mounting holes 13 of another radiation fin 11a or 11b. Further, the inner diameter B of the outer step portions 131 of the double-step mounting holes 13 of the radiation fins 11a and 11b is slightly smaller than the outer diameter D of the heat pipes 2 so that the heat pipes 2 can be tightly fitted into the double-step mounting holes 13 of the radiation fins 11a and 11b to enhance engagement between the respective outer step portions 131 and the respective inner step portions 132. Therefore, the radiation fins 11a and 11b and the heat pipes 2 are firmly secured together to provide a high strength against impact during delivery or installation. Further, because the radiation fins 11a and 11b are kept in close contact with the heat pipes 2, the cooler module provides excellent heat transfer and dissipation effects.

Further, the radiation fins 11a and 11b have the respective bottom edge configured to fit the configuration of the top wall of the base block 3. The heat pipes 2 each have a flat bottom wall disposed in flush with the bottom wall of the base block 3. Further, the thermal pad 4 is bonded to the bottom wall of the base block 3 to wrap the heat pipes 2 tightly (see FIG. 3). After installation, the thermal pad 4 has its top and bottom surfaces respectively disposed in contact with the flat bottom walls of the heat pipes 2 and the hot side of the electronic chip (such as CPU or GPU). When the thermal pad 4 and the heat pipes 2 are hot during dissipation of heat from the electronic chip, the heat expansion effect reinforces the surface contact between the heat pipes 2 and the thermal pad 4. Therefore, heat can be transferred from the electronic chip to the heat pipes 2 rapidly for quick dissipation.

A prototype of cooler module has been constructed with the features of FIGS. 16. The cooler module functions smoothly to provide all of the features discussed earlier.

Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.