HEAT SINK ASSEMBLY WITH HEAT PIPE

Abstract

A heat sink assembly with heat pipe includes at least one aluminum fin assembly and at least one copper heat pipe, which are made of dissimilar metal materials. The aluminum fin assembly includes at least one area to be connected to other members of the heat sink assembly, such as a groove. A copper embedding layer is provided on a groove inner surface of the groove for connecting the aluminum fin assembly to the copper heat pipe. By providing the copper embedding layer, the connection between the aluminum fin assembly and the copper heat pipe made of dissimilar metal materials is improved, and the problems of eutectic grains formed on the surface of the aluminum fin assembly and environmental pollution caused by electroless nickel plating are eliminated.

Claims

1. A heat sink assembly with heat pipe, comprising: at least one aluminum fin assembly being formed of a plurality of aluminum fins sequentially fastened to one another, and having a bottom surface and a top surface; any two adjacent ones of the aluminum fins defining a flow passage between them; the bottom surface being provided with at least one groove, which has an open side and a groove inner surface; the aluminum fins being respectively provided with a through hole that extends through the aluminum fin in a thickness direction thereof, and the through holes respectively including a flange, which is projected from one side of the aluminum fin; the groove inner surface being an area of the aluminum fin assembly for connecting to other members of the heat sink assembly and being provided with a copper embedding layer thereon, which includes a deepening surface and a connecting surface; and the deepening surface bonding to and deeply penetrating into the groove inner surface; and at least one copper heat pipe having a first end and a second end extended through the through holes and the groove on the aluminum fin assembly, respectively; and the first end being connected to the flanges by tight fit, and the second end being in contact with and connected to the connecting surface of the copper embedding layer provided on the groove inner surface.

2. The heat sink assembly with heat pipe as claimed in claim 1, wherein the second end of the at least one copper heat pipe has an exposed surface and a contact surface; and the exposed surface being exposed from the groove while the contact surface being in contact with and connected to the connecting surface of the copper embedding layer provided on the groove inner surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

[0022] FIGS. 1A and 1B are exploded and assembled bottom perspective views, respectively, of a heat sink assembly with heat pipe according to a preferred embodiment of the present invention;

[0023] FIG. 1C is an assembled top perspective view of the heat sink assembly with heat pipe according to the preferred embodiment of the present invention;

[0024] FIG. 1D shows an outermost fin of an aluminum fin assembly included in the present invention is turned inside out to connect to other fins;

[0025] FIG. 2A is a sectional view of the aluminum fin assembly in the present invention;

[0026] FIG. 2B is a sectional view showing the connecting of the aluminum fin assembly with a copper heat pipe; and

[0027] FIGS. 3A and 3B show the aluminum fin assembly before and after being provided with a copper embedding layer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] The present invention will now be described with some preferred embodiments thereof and the accompanying drawings.

[0029] Please refer to the accompanying drawings; wherein FIGS. 1A and 1B are exploded and assembled bottom perspective views, respectively, of a heat sink assembly with heat pipe according to the present invention, FIG. 1C is an assembled top perspective view of the present invention, FIG. 1D shows an outermost fin of an aluminum fin assembly included in the present invention is turned inside out to connect to other fins, FIG. 2A is a sectional view of the aluminum fin assembly in the present invention, and FIG. 2B is a sectional view showing the connecting the aluminum fin assembly with a copper heat pipe. As shown, the heat sink assembly is a heat sink structure 10 including an aluminum fin assembly 11 and at least one copper heat pipe 121. The aluminum fin assembly 11 has a bottom surface 113 and a top surface 116. On the bottom surface 113, there is provided at least one groove 115. In the illustrated preferred embodiment, two grooves 115 are shown. Every groove 115 has an open side 1151 located flush with the bottom surface 113 and a groove inner surface 1152 recessed from the bottom surface 113. The bottom surface 113 and the groove inner surfaces 1152 are areas on the aluminum fin assembly 11 to be connected to other copper parts as will be described in detail later.

[0030] The aluminum fin assembly 11 is formed of a plurality of fins 111 sequentially fastened to one another in a horizontal direction or a vertical direction, and any two adjacent fins 111 define a flow passage 117 between them. The fins 111 are made of aluminum or an aluminum alloy. In the illustrated preferred embodiment, every aluminum fin 111 has an upper bent edge 1111 and a lower bent edge 1112, which are projected from one side of the aluminum fin 111 to align with the upper bent edge 1111 and the lower bent edge 1112 of another adjacent aluminum fin 111. The upper bent edge 1111 and the lower bent edge 1112 are respectively provided with at least one fastening section 11111, 11121. In the illustrated preferred embodiment, the fastening sections 11111, 11121 are snap-fit structures. However, it is understood the illustration is non-restrictive and other known technical means for fastening may also be adopted. The aluminum fins 111 are sequentially horizontally connected to one another by snap fitting the fastening sections 11111, 11121 of one aluminum fin 111 to the fastening sections 11111, 11121 on another adjacent aluminum fin 111 to thereby form a heat sink structure with snap-fitted fins.

[0031] With the above arrangements, the upper bent edges 1111 together form the top surface 116 of the aluminum fin assembly 11, and the lower bent edges 1112 together form the bottom surface 113 of the aluminum fin assembly 11. Further, the lower bent edge 1112 of every aluminum fin 111 is provided with at least one downward opened recess. When the aluminum fins 111 are sequentially fastened together, the downward opened recesses are aligned with one another to constitute the groove 115 on the bottom surface 113. Further, the aluminum fins 111 are respectively provided with at least one through hole 114, which extend through the aluminum fin 111 in a thickness direction thereof and are aligned with one another. Every through hole 114 has a flange 1141 formed around a rim thereof and projected from one side of the aluminum fin 111. In the illustrated preferred embodiment, the flanges 1141 are projected from a front side of the aluminum fins 111. The flanges 1141 respectively define a flange inner surface 1143. In practical implementation of the present invention, the aluminum fin assembly 11 may be otherwise formed by sequentially vertically fastening the aluminum fins 111 to one another. As can be seen in FIG. 1D, an outermost aluminum fin 111 of the aluminum fin assembly 11 is turned inside out when being connected to an adjacent aluminum fin 111, so that no upper bent edge 1111 and lower bent edge 1112 would expose to outside and undesirably scratch other members of the heat sink assembly.

[0032] In the illustrated preferred embodiment, there are shown two copper heat pipes 121, which can be U-shaped heat pipes, for example, and made of copper or a copper alloy. The copper heat pipes 121 can be, for example, round, D-shaped or flat in cross section. Each of the copper heat pipes 121 includes a first end 1211 and a second end 1212. The first ends 1211 are extended through the through holes 114 and connected to the flanges 1141 through tight fit. For example, the flange inner surfaces 1143 of the flanges 1141 respectively have an inner diameter slightly smaller than an outer diameter of the first ends 1211 of the copper heat pipes 121, so that an interference fit is formed between the flanges 1141 and the first ends 1211 of the copper heat pipes 121. Or, according to the principle of thermal expansion, the aluminum fins 111 can be heated to expand the inner diameter of the flanges 1141 and then let the fins 111 cool after the copper heat pipes 121 are fully extended through the through holes 114. At this point, the inner diameter of the cooled flanges 1141 is naturally reduced to its original size to form a tight fit between the flanges 1141 and the copper heat pipes 121. The second ends 1212 are extended to the bottom surface 113 of the aluminum fin assembly 11 and through the grooves 115. As can be seen in FIG. 1A, the second ends 1212 of the copper heat pipes 121 respectively have an exposed surface 12121 corresponding to the open side 1151 of the groove 115 and a contact surface 12122 facing toward the groove inner surface 1152.

[0033] In the illustrated present invention, every copper heat pipe 121 has a U-shaped section 1213 formed between the first end 1211 and the second end 1212 to extend from the first end 1211 to the second end 1212. The first end 1211 and the second end 1212 of each copper heat pipe 121 serve as a condensation end and an evaporation end, respectively. The copper heat pipe 121 also has at least one wick structure and a working fluid provided therein. The at least one wick structure may be, for example, a plurality of grooves, a powder sintered structure, a mesh structure, a fibrous structure, a corrugated plate, or any combination thereof extended in the copper heat pipe 121 from the first end 1211 to the second end 1212.

[0034] In the copper heat pipe 121 illustrated in the preferred embodiment, the first end 1211 is round in cross section while the second end 1212 is D-shaped or flat in cross section. That is, the exposed surface of the second end 1212 is a flat surface formed by, for example, pressing with a tool or milling with a milling cutter and is located flush with the bottom surface 113 of the aluminum fin assembly 11. However, the above illustration is non-restrictive. In other alternative embodiments, the first end 1211 and the second end 1212 can be the same in cross section, such as a round or a flat cross section.

[0035] In an alternative embodiment, the flange 1141 on every aluminum fin 111 has a corrugated or notched structure formed around it for forming an interference fit between an outer surface of the first end 1211 of the copper heat pipe 121 and the flange 1141. More specifically, after the first end 1211 of the copper heat pipe 121 is extended through the through hole 114, the flange 1141 is compressed with a tightening device to form the corrugated or notched structure. The corrugated or notched structure includes a plurality of protrusions and dents, which are continuously and alternately arrayed along a circumferential surface of the flange 1141 to apply a radially inward force on the copper heat pipe 121, causing an outer surface of the latter to deform. Further, interference fit is formed between the deformed outer surface of the copper heat pipe 121 and the flange 1141 with the corrugated or notched structure. In this manner, the first end 1211 of the copper heat pipe 121 is fixedly held to the aluminum fins 111 without the risk of separating from the through holes 114.

[0036] FIGS. 3A and 3B show the aluminum fin assembly 11 before and after being provided with a copper embedding layer 14. Please refer to FIGS. 3A and 3B along with FIGS. 1A, 1B, 2A and 2B. A copper embedding layer 14 is provided at areas of the aluminum fin assembly 11 corresponding to the groove inner surfaces 1152 and the bottom surface 113, at where the aluminum fin assembly 11 is to be connected to other members of the heat sink assembly. The copper embedding layer 14 includes a deepening surface 141 and a connecting surface 142, which are located at two opposite sides of the copper embedding layer 14. The deepening surface 141 bonds or grips to, is embedded or buried in, or is deposited on the groove inner surfaces 1152 and the bottom surface 113; and the connecting surface 142 is an exposed surface of the copper embedding layer 14 for contacting with and connecting to other members of the heat sink assembly. In some operable embodiments, the copper embedding layer 14 can be copper sheet, copper foil, copper powder/granules, or liquid copper applied to the groove inner surfaces 1152 and the bottom surface 113 through mechanical processing, such as pneumatic pressing, hydraulic pressing, stamping, oil pressing, extruding or hammering; or through surface finishing, such as spraying, electroplating or printing; or through chemical processing, such as electroplating or anodizing. In the course of forming the copper embedding layer 14, a part of the copper embedding layer 14 directly grips to, is embedded or buried in, deeply penetrates into, or is deposited on the groove inner surfaces 1152 and the bottom surface 113 to form the deepening surface 141 of the copper embedding layer 14.

[0037] Therefore, the copper embedding layer 14 is not only connected at the connecting surface 142 to the groove inner surfaces 1152 and the bottom surface 113, but also has the deepening surface 141 gripped to, embedded or buried in, or deposited on the groove inner surfaces 1152 and the bottom surface 113 to form a foundation of the copper embedding layer 14, which increases the binding strength between the copper embedding layer 14 and the groove inner surfaces 1152 and the bottom surface 113 and prevent the copper embedding layer 14 from peeling off or separating from the groove inner surfaces 1152 and the bottom surface 113.

[0038] With the above arrangements, the grooves 115 on the aluminum fin assembly 11 can be connected to the contact surfaces 12122 of the second ends 1212 of the copper heat pipes 121 via the connecting surface 142 of the copper embedding layer 14 on the groove inner surfaces 1152. More specifically, for example, solder can be used between the connecting surface 142 of the copper embedding layer 14 and the contact surfaces 12122 of the copper heat pipes 121 to weld them to one another. Alternatively, the connecting surface 142 of the copper embedding layer 14 and the contact surfaces 12122 of the copper heat pipes 121 can be connected together by supersonic welding or laser welding. Thus, the aluminum fin assembly 11 can be directly welded to the copper heat pipes 121 made of a dissimilar metal material without the need of electroless nickel plating.

[0039] In the present invention, the bottom surface 113 of the aluminum fin assembly 11 may be optionally connected to a heat conducting base made of a copper-based material, such as pure copper or any copper alloy. The heat conducting base can be a solid base plate or a hollow vapor chamber internally provided with a working fluid. The bottom surface 113 can be connected, such as by welding, to the copper-based heat conducting base via the connecting surface 142 of the copper embedding layer 14, while the exposed surfaces at the second ends 1212 of the copper heat pipes 121 can also be directly connected, such as by welding, to the copper-based heat conducting base. With the copper embedding layer 14, the aluminum fin assembly 11 can be directly welded to the copper-based heat conducting base made of a dissimilar metal material without the need of electroless nickel plating. Thus, no toxic substances would be produced in the manufacturing process of the heat sink structure 10 to ensure good environmental protection and the problem of forming eutectic as found in the prior art is also improved.

[0040] In the illustrated preferred embodiment, the two copper heat pipes 121 are extended from the same side into the aluminum fin assembly 11. However, it is understood the illustration is non-restrictive. In other alternatively embodiments, the heat sink structure 10 can include a plurality of copper heat pipes 121 and the aluminum fin assembly 11 is formed with through holes and grooves 115 respectively in a number the same as the copper heat pipes 121; and the copper heat pipes 121 can be arranged at staggered or non-staggered locations and extended into the aluminum fin assembly 11 from two opposite sides thereof to upgrade the heat dissipation efficiency of the heat sink structure 10.

[0041] The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.