Heat sink having heat-dissipating fins of large area and method for manufacturing the same

A heat-dissipating fin of a large area is made of a metallic sheet and has a fin body. An outer edge of one side of the fin body extends to form a sheet-like expanding portion. The expanding portion is bent and overlapped on the fin body to obtain the heat-dissipating fin. A heat sink includes a plurality of heat-dissipating fins and a heat-conducting element, which is formed by means of penetrating the respective heat-dissipating fins with a condensing section of the heat-conducting element.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat sink, and in particular to a heat-dissipating fin of a large area capable of increasing the total heat-dissipating area in a stack of heat-dissipating fins, a heat sink having such heat-dissipating fins, and a method for manufacturing the same.

2. Description of Prior Art

With the rapid advancement of the computer industry, the operating speed of electronic elements increases to a much larger extent, and thus the amount of heat generated by the electronic elements is increased accordingly. Therefore, in order to maintain the electronic elements to operate continuously at an admissible range of temperature. It is well known to use a heat sink to dissipate the heat generated by the electronic elements. The current heat sink is usually provided with a heat pipe, in which a heat-conducting substance is used to help the heat sink to dissipate the heat by means of the phase change between the liquid state and the vapor state of the heat-conducting substance. In addition, heat-dissipating fins penetrate a condensing end of the heat pipe also has have an influence on the total heat-dissipating efficiency.

In an aluminum-extruded heat sink, owing to the limitation in the conventional manufacturing process, the heat-dissipating fins must have a certain thickness and pitch, and these heat-dissipating fins are stacked up to form a heat sink. Since the heat-dissipating fin is thinner and the pitch between the respective heat-dissipating fins is small, the whole heat-dissipating area of the heat sink can be increased substantially, and thus the heat-dissipating efficiency can be improved. However, in order to further increase the area of the fins in the heat sink, manufacturers in this field attempt to increase the dimension of each heat-dissipating fin to thereby increase the total heat-dissipating area. Further, the heat-dissipating fin can be made waved to increase the heat-dissipating area. Although the above-mentioned solutions can increase the heat-dissipating area of the heat sink, the increase is so limited and the volume of the whole heat sink may be adversely increased.

Therefore, in order to solve the above-mentioned problems, the present Inventor proposes a reasonable and novel structure based on his deliberate research and expert experiences.

SUMMARY OF THE INVENTION

The present invention is to provide a heat-dissipating fin of a large area, a heat sink having such heat-dissipating fins, and a method for manufacturing the same. Without increasing the volume of the heat-dissipating fin significantly, the area of the heat-dissipating fins can be increased substantially by means of bending and overlapping the heat-dissipating fins. Then, the plurality of heat-dissipating fins can be used to form a heat sink. Thus, the heat-dissipating efficiency of the heat-dissipating fins or the heat sink can be increased.

The present invention is to provide a heat-dissipating fin of a large area, which has a fin body. An outer edge of one side of the fin body extends to form a sheet-like expanding portion. The expanding portion is bent and overlapped on the fin body.

The present invention provides a heat sink having heat-dissipating fins of a large area, which includes a plurality of heat-dissipating fins and a heat-conducting element having a heat-absorbing section and a condensing section. Each of the heat-dissipating fins has a fin body. An outer edge of one side of the fin body extends to form a sheet-like expanding portion. The expanding portion is bent and overlapped on the fin body. Each of the heat-dissipating fins is provided with corresponding through-holes. The condensing section of the heat-conducting element penetrates the through-hole of each heat-dissipating fin. In this way, the heat-dissipating fins can be overlapped on the condensing section of the heat-conducting element.

The present invention provides a method for manufacturing a heat sink having heat-dissipating fins of a large area, which includes the steps of:

a) preparing a heat-conducting element and a plurality of heat-dissipating fins, the heat-conducting element having a heat-absorbing section and a condensing section, each of the heat-dissipating fins having a fin body, an outer edge of one side of the fin body extending to form a sheet-like expanding portion;

b) bending and overlapping the expanding portion of each heat-dissipating fin toward the fin body;

c) punching through-holes on the respective heat-dissipating fins; and

d) penetrating the through-holes of the respective heat-dissipating fins by the condensing section of the heat-conducting element.

DETAILED DESCRIPTION OF THE INVENTION

In order to make the Examiner further understand the characteristics and technical contents of the present invention, a detailed description will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit the present invention.

The present invention provides a heat-dissipating fin of a large area. Please refer toFIGS. 1 and 2.FIG. 1is a flow chart showing the process for manufacturing the heat-dissipating fin according to the present invention, andFIG. 2is a view showing the external appearance of the heat-dissipating fin according to a first embodiment of the present invention. The heat-dissipating fin1has a fin body10made of metallic materials of good heat-dissipating property. An outer edge of one side of the fin body10extends to form a sheet-like expanding portion11. The outer edge has a first width, the sheet-like expanding portion connecting at the outer edge has a second width, and the second width is smaller than the first width so that a protrusion101is formed at each of two corners of the outer edge. The expanding portion11is used to increase the heat-dissipating area of the heat-dissipating fin1. The expanding portion11is bent and overlapped on the fin body10. Thus, in this way, without increasing the volume of the heat-dissipating fin1, the total heat-dissipating area can be increased.

Please refer toFIGS. 1 and 3. In a step S10, first, a metallic sheet of good heat-dissipating property is prepared, by means of which the heat-dissipating1can be made. The metallic sheet is made flat and expanded (as shown inFIG. 3) by means of a press-forming process, thereby forming the fin body10. At least an outer edge of one side of the fin body10extends to form a sheet-like expanding portion11.

Please refer toFIGS. 1 and 4. In a step S20, the expanding portion11is bent toward the fin body10, so that the expanding portion11is overlapped on the fin body10. In this step, a curved section100bent reversely is integrally formed between the fin body10and the expanding portion11, so that a gap is formed between the fin body10and the expanding portion11and thus the total area of both surfaces of the expanding portion11can be used for heat dissipation. In the present embodiment, the expanding portion11comprises a first extending section110, a perforated section111and a second extending section112. The first extending section110extends from the outer edge of one side of the fin body10. A curved section100is integrally connected to the fin body10. A gap is formed between the first extending section110of the expanding portion11and the fin body10.

The perforated section111of the expanding portion11is formed by extending from the distal edge of the first extending section110, so that it can be perforated. As shown inFIG. 5, by means of a perforating punch4, through-holes14can be made on the fin body10corresponding to the perforated section111. In the present embodiment, the perforating punch4penetrates into the fin body4to form respectively an outer annular wall13on the perforated section111and an inner annular wall12on the fin body10to be located inside the outer annular wall13. Inside the inner annular wall12and the outer annular wall13, a through-hole14is formed for allowing a heat-conducting element (later described) to penetrate therein. On the contrary, the perforating punch4can penetrates into the perforated section111, so that the inner annular wall12can be formed on the perforated section111and the outer annular wall13can be formed on the fin body10. In this way, a through-hole14identical to the previous one can be also formed.

The second extending section112of the expanding portion11is formed by extending from the distal edge of the perforated section111, thereby increasing the heat-dissipating area of the heat-dissipating fin1. The second extending section112is inclined upwards from the fin body10without contacting the fin body10. With this arrangement, the second extending section112can have a larger surface area to contact with air for better heat dissipation.

In the present embodiment, the outer edges of both sides of the fin body10can be extended to form an expanding portion11respectively. The extended length of the expanding portion11can be smaller than half of the fin body10. Alternatively, in the previous case that only one side of the fin body10is provided with the expanding portion11, the extended length of the expanding portion11is smaller than that of the fin body10.

Further, please refer toFIG. 6, which is a partially cross-sectional view showing the second embodiment of the heat-dissipating fins of the present invention. Under the circumstance that the expanding portion11of the heat-dissipating fin1has only one first extending section110, the fin body10is provided with the inner annular wall12and the through-hole14. The present embodiment also allows a heat-conducting element (later described) to penetrate therein.

In addition, the present invention also provides a heat sink having such heat-dissipating fins and a method for manufacturing the same. Please refer toFIGS. 7 to 9.FIG. 7is a flow chart showing the process for manufacturing the heat sink of the present invention.FIG. 8andFIG. 9are an exploded perspective view and an assembled perspective view showing the heat sink according to the first embodiment of the present embodiment respectively. The heat sink includes a plurality of heat-dissipating fins1and at least one heat-conducting element2. The heat-conducting element2penetrates the through-holes14of the respective heat-dissipating fins1, thereby forming a heat sink having the heat-dissipating fins. Without increasing the volume occupied by the respective heat-dissipating fins significantly, the total heat-dissipating area can be increased.

Please refer toFIGS. 7 and 4. In a step S11, first, at least one heat-conducting element2and the plurality of heat-dissipating fins1are prepared. Since the heat-dissipating fins1have been described in the above paragraphs, the description thereof is omitted for clarity. The heat-conducting element2may be a heat pipe or a vapor chamber, which is formed to have a heat-absorbing section20and at least one condensing section21. In the present embodiment, the heat-conducting element2is a heat pipe, which is formed into U shape. The bottom section of the U-shaped heat pipe is configured as the heat-absorbing section21, while both ends of the U-shaped heat pipe are configured as the condensing sections21respectively.

Please refer toFIGS. 7 and 4. In a step S21, the expanding portion11of each heat-dissipating fin1is bent toward the fin body10, so that the expanding portion11of each heat-dissipating fin1can be overlapped on the fin body10. Since this step is the same as that in the process for manufacturing the heat-dissipating fins1, the only difference is to make a plurality of heat-dissipating fins in this step. Thus, the description relating thereto is omitted for clarity.

Please refer toFIGS. 7 and 5. In a step S31, the thus-formed heat-dissipating fins1are punched to form through-holes14respectively. The through-holes14on the respective heat-dissipating fins1correspond to each other. The description of this step is the same as that in the above.

Please refer toFIGS. 7 and 8. In a step S41, the condensing section21of the heat-conducting element2penetrates the through-holes14of the respective heat-dissipating fins1, thereby forming a heat sink (as shown inFIG. 9) having a stack of heat-dissipating fins. Please refer toFIGS. 8 to 10, in order to bring the heat-absorbing section20of the heat-conducting element2into surface contact with a heat-generating source (not shown) more easily, the heat sink further comprises a base3. The base3is provided on the heat-absorbing section20of the heat-conducting element2to be thermally connected thereto. The bottom surface of the base3is provided with a groove30for allowing the heat-absorbing section20of the heat-conducting element2to be embedded therein. The heat-absorbing section20of the heat-conducting element2can be also emerged from the bottom surface of the base3, thereby contacting a heat-generating source (not shown) directly.

Please refer toFIG. 11, which is a cross-sectional view showing the heat sink according to the second embodiment of the present invention. If only one side of each of the heat-dissipating fins1is provided with the expanding portion11, the heat-dissipating fins1can be arranged in a staggered manner, thereby facilitating to overlap these heat-dissipating fins1.

Please refer toFIG. 12, which is a cross-sectional view showing the heat sink according to the third embodiment of the present invention. The heat-conducting element2is a vapor chamber that cooperates with the through-holes14. The other structural characteristics are the same as those in the previous embodiments.

According to the above, the present invention really achieve the desire objects and solves the problems of prior art. Further, the present invention demonstrates industrial applicability, novelty and inventive steps and thus conforms to the requirements for an invention patent.