Patent Application
20090145580
1. Field of the Invention
The present invention relates to a heat sink, and more particularly to a heat sink which is used to remove heat from an electronic component. The present invention is also related to a method of manufacturing the heat sink.
2. Description of Related Art
With the advance of integrated circuit (IC) technology, CPUs are made more and more compact and has higher operation speed than old ones. Thereby, a great deal of heat is generated. However in current trend, it is desired that the electronic devices have compact size, that is, they are smaller, and thus, it is required that the heat dissipating devices of the electronic devices are compact and has powerful heat dissipating ability.
Referring to
Although above the structure can be used, gaps are generated between the fins 4 and the recesses 31. The lower ends of the fins 4 are straight, thus contact areas between the substrate and the fins are small. Heat generated by the CPUs will be transferred to the substrate 3 and thus to the fins 4. The heat can not be quickly transferred to the whole fins since the gaps and the small contact areas between the fins 4 and the recesses 31.
A solution for enhancing the contact areas between the fins and the substrate of the heat sink is needed.
A heat sink includes a base plate and a plurality of thin-sheet fins. The base plate has a plurality of recesses and protruding ribs formed between every two recesses. The protruding ribs are spaced by the respective recesses with an equal space. Each thin-sheet fin comprises a folded engaging portion and a dissipating portion connecting with the engaging portion. The engaging portion has a first extending portion and a second extending portion parallel to the first extending portion and connecting with the first extending portion. The engaging portions are inserted into the recesses of the base plate and abut against a bottom of the recesses.
Other advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
Many aspects of the present heat sink 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 heat sink. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
Referring to
Each thin-sheet fin 20 comprises a folded engaging portion 21 and a dissipating portion 28 connecting with the engaging portion 21 and perpendicularity to the bottom surface of the base plate 10. Each engaging portion 21 comprises a curved first extending portion 22 and a curved second extending portion 24 substantially parallel and close to the first extending portion 22. Each first extending portion 22 has an upper vertical portion 225 connecting with the dissipating portion 28, and an inclined portion 226 distant to the dissipating portion 28. The inclined portion 226 connects with the vertical portion 225 in a manner such that there is an obtuse angle between the vertical portion 225 and the inclined portion 226. Each second extending portion 24 has a lower inclined portion 246 connecting with a bottom end of the inclined portion 226 of the first extending portion 22, and an upper vertical portion 245 connecting with the inclined portion 226. The inclined portions 226, 246 are close to each other and the vertical portions 225, 245 are close to each other. The vertical portion 245 of each second extending portion 24 has a free end 247.
In assembly, the engaging portions 21 of the thin-sheet fins 20 are inserted into the recesses 12 of the base plate 10 with the dissipating portions 28 being perpendicularity to the bottom surface of the base plate 10, wherein the vertical portions 225, 245 of the engaging portions 21 are received in the vertical recesses of the recesses 12, and the inclined portion 226, 246 are received in the inclined recesses. The first and second extending portions 22, 24 of the engaging portions 21 attach to the side faces of the recesses 12. The free end 247 of the second extending portion 24 of each thin-sheet fin 20 abuts against the projection 19 of each protruding rib 15 of the base plate 10. A plurality of punching sheets (not show) punch the dents 18 of the protruding ribs 15 of the base plate 10, then the protruding ribs 15 are extruded downwards and produce plastic deformations. The engaging portions 21 of the thin-sheet fins 20 are clamped by side faces of the recesses 12 by plastic deformations of the protruding ribs 15. Thus the protruding ribs 15 are brought into contact with the thin-sheet fins 20. Therefore, the thin-sheet fins 20 are tightly secured to the recesses 12 and the heat sink is formed.
Because the engaging portion 21 of each thin-sheet fin 20 has the folded first and second extending portions 22, 24 respectively contacting with the side faces of recesses 12, the contact areas between the thin-sheet fins 20 and the protruding ribs 15 are so larger that the heat dissipating effect of the heat sink is improved. Furthermore, the free end 247 of the second extending portion 24 of each thin-sheet fin 20 abuts against the projection 19 of each protruding rib 15 of the base plate 20, so that the thin-sheet fin 20 is firmly crimped by the base plate 20. Since each of the protruding rib 15 has a dent 18, each of the punching sheets can punch on the protruding ribs 15 more exactly and easily.
A method of manufacturing the heat sink in the first embodiment comprising the steps of:
a) forming a plurality of recesses 12 at a top surface of a base plate 10 and protruding ribs 15 respectively spaced by the recesses 12 by aluminum extrusion, the protruding ribs 15 has a dent 18 on a center of a top surface thereof;
b) folding an end of each thin-sheet fin 20 to form a vertical dissipating portion 28 and an engaging portion 21 having a first extending portion 22 and a second extending portion 24 parallel and close to the first extending portion 22; curving the first and second extending portion 22, 24 so that the first extending portion 22 has an upper vertical portion 225 and a lower inclined portion 226 connecting with the vertical portion 225, and the second extending portion 24 has a lower inclined portion 246 and an upper vertical portion 245;
c) inserting the engaging portions 21 of the thin-sheet fins 20 in the recesses 12 from a side of the base plate 10 along extending directions of the recesses 12; and
d) punching the dent 18 of the protruding ribs 15 by plastic deformations of protruding ribs 15, the side faces of the recesses 12 crimping the thin-sheet fins 20 in the recesses 12.
The base plate 10a is similar to the base plate 10 in the first embodiment. The base plate 10a has a bottom surface and a top surface opposite to the bottom surface. The base plate 10a defines a plurality of recesses 12a at the top surface thereof and forming protruding ribs 15a spaced by the respective recesses 12a with equal spaces. Each recess 12a has two side faces (not labeled) on the two adjacent protruding ribs 15a. The two side faces of each recess 12a have wavy configurations corresponding to the first and second extending portions 22a, 24a of the engaging portion 21a of each thin-sheet fin 20a.
A method of manufacturing the heat sink in the second embodiment is similar to that in the first embodiment, only the step b) comprises folding an end of each thin-sheet fin 20a to form an engaging portion 21a having a first extending portion 21a and a second extending portion 22a parallel to the first extending portion 21a; curving the first and second extending portion 22a, 24a into wavy configurations.
In the second embodiment, the engaging portions 21a of the thin-sheet fins 20a having wavy configurations are engaged into the recesses 12a of the base plate 10a correspondingly having wavy configurations. Thus the thin-sheet fins 20a are not easy to be drawn out from the base plate 10a, and the contact areas between the thin-sheet fins 20a and the protruding ribs 15a are so larger that the heat dissipating effect of the heat sink is improved.
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.
