FIELD OF THE INVENTION
- BACKGROUND OF THE INVENTION
The present invention relates to a cooling apparatus for electronic devices and particularly to a cooling fin assembly, which has fins coupled in series and is arranged in an annular fashion.
As the operation clock frequencies of central processing units (CPUs) become faster, the performance of computers also increases significantly. More electric power is consumed and more heat is generated. The peripheral devices such as hard disk drives, compact disk drives, graphic chips and system core logic chipsets also generate more heat as the performances are enhanced. Hence an enhanced cooling device has to be provided to transfer the heat energy of the computer to the surrounding environment, to prevent the computers from being overheated and malfunctioned.
The CPU is the brain of a computer. As it is in an operating condition constantly and processes at a high clock frequency, the CPU generates a lot of heat. Heat dissipation is the most important issue. If the CPU cannot be cooled effectively, computer operation could be malfunctioned, and CPU bum out could happen.
The conventional cooling methods now being adopted for the CPU mainly rely on a combination of fins and fans. Although liquid cooling or heat pipe devices have been developed to enhance heat transfer, the cooling methods that use liquid as a heat transfer medium are difficult to fabricate and install, and leaking of working fluid is still a problem not yet fully resolved. Hence a heat sink fin assembly with fins still has to be used to cool the working fluid. Therefore the heat sink fin assembly is an indispensable cooling device at present.
The heat sink fin assembly has a base, directly in contact with the heat source, such as the surface of an electronic chip set like CPU to transfer heat to the fins on the base. The heat is carried away by heat convection. A fan may be added to generate airflow, to form a forced convection condition to enhance heat transfer. According to the manufacturing method, the heat sink fin assembly generally can be classified into two types. One of the two types mostly is made of aluminum by extrusion, which has a lower thermal resistance, lighter weight, lower cost and may be made easily by extrusion. But the fins, formed by aluminum extrusion have a limited fin pitch and cannot increase heat transfer area as desired. The other type is to mount copper fins on an aluminum or copper base, in which the fins can be arranged in a very small pitch to form a heat transfer area to increase cooling efficiency.
To speed up the mounting operation of the fins, many types of serial fin coupling designs have been introduced. These designs couple a plurality of fins in series through latches. Each fin has a bottom plate bent on one edge. The bottom plates of the fins are coupled and juxtaposed to form a planar area, to be mounted on a base or directly in contact with the surface of a heat source.
- SUMMARY OF THE INVENTION
Refer to FIG. 1 for a conventional heat sink 1. The heat sink 1 is formed substantially rectangular, which includes a plurality of fins 2 in parallel on a base 3. The fins 2 form an air passage between them. A fan 4 is mounted on the top of the heat sink 1 to generate airflow that is directed downwards, to the surface of the heat sink 1, and dispelled through the front and rear sides of the heat sink 1. The fins 2 on the conventional heat sink 1 have only two sides to channel the airflow, and the airflow rate is limited. Moreover, the fan 4 directs the airflow downwards, to directly hit the base of the heat sink 1. The speed of the airflow decelerates greatly and the flow resistance increases. To remedy this problem, R.O.C. patent No. M245505 discloses a heat sink assembly with the fins arranged in an annular fashion and mounted on a conical metal element to increase the airflow passages. But reference No. M245505 does not teach how to arrange the fins in an annular fashion and couple the fins on the metal element. Arranging the fins rapidly in an annular fashion and mounting on a base still has technical problems in actual implementation. Moreover, while the aforesaid designs which couple fins in series provide a serial coupling structure, coupling structure is located on the top and bottom ends of the fins. The fins coupled in series can only be arranged in a linear fashion and cannot be altered to mate the base. Hence, how to make arrangement of the fins more versatile, and form an annular arrangement easily to become a circular fin assembly to be mounted on a heat source or a base securely, are still technical issues remained to be resolved.
In view of the aforesaid problems, the primary object of the present invention is to provide a cooling fin assembly that has fins coupled in series and forms an annular arrangement so that the entire perimeter of the cooling fin assembly becomes airflow channels, thereby reducing the resistance of cooling airflow and increasing cooling efficiency.
In order to achieve the foregoing object, the cooling fin assembly according to the invention includes a plurality of fins coupled in series and formed in an annular fashion. Each fin has an outer edge, an inner edge, a top edge and a bottom edge. After coupled and formed in the annular fashion. The top edge and the bottom edge have respectively a latching element extended outwards in the middle. The latching element has a latching section on the end of the latching element and a latch opening on the juncture the latching element and the fin, to be coupled with the latching section of another fin. The fin, further, has a bottom plate extending vertically from the bottom edge thereof. A strapping ring is provided to surround the outer edge of the fins. By means of the construction set forth above, the fins that are serially coupled and formed in an annular fashion are distributed radially. Thus airflow can be channeled in any direction, to reduce flow resistance and increase the cooling efficiency.
The cooling fin assembly further includes a base, which has a top surface to be in contact with the bottom plate of the fins. The base has a bottom surface in contact with the surface of a heat source, to transfer heat to the fins and dissipate the heat by convection.
To anchor a fan securely on the fins, the invention further has a plurality of anchoring elements which have one end fastened to the peripheral edge of the fan and another end latched on the outer edge of the fins.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
FIG. 1 is a perspective view of a conventional heat sink.
FIG. 2A is a fragmentary schematic view of an embodiment of the invention showing the radiation fins;
FIG. 2B is a fragmentary enlarged views of FIG. 2A;
FIG. 3 is a fragmentary sectional view of the invention showing the fins and the base;
FIG. 4 is an exploded view of the invention;
FIG. 5 is a side view of the invention;
FIG. 6 is a perspective view of the invention; and
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 7 is a fragmentary sectional view of another embodiment of the invention.
Referring to FIGS. 2A and 2B, the cooling fin assembly according to the invention comprises a plurality of fins 10 coupled in series and arranged in a desired form, such as a linear fashion or an annular fashion.
The fins 10 are made of thermal conductive material such as aluminum or copper and formed by punching. Each of the fins 10 has an inner edge 11, an outer edge 12, a top edge 13 and a bottom edge 14. After coupled and arranged in an annular shape. The middle portions of the top edge 13 and bottom edge 14 have respectively a latching element 15 extended vertically towards the same side and is integrally formed on the fin 10 by punching. The latching element 15 has a latching section 151 on the end of the fin 10 that has protrusions 151 a on two edges. There is a latching opening 152 formed on a juncture the latching element 15 and the fin 10 to receive the latch section 151 of another fin 10. The two protrusions 151 a have pointed ends spaced from each other at a distance greater than the width of the latching opening 152, so that the latching section 151 can be latched securely in the latching opening 152. Moreover, there is a slot 151 b on the end of the latching section 151 to divide the latching section 151 into two parts axially, so that the latching section 151 has elasticity and may be deformed to change the distance between the two protrusions 151 a during insertion of the latching section 151 into the latching opening 152.
The bottom edge 14 abutting the inner edge 11 has a bottom plate 141 extended vertically from the fin 10. The bottom plate 141 is fan-shaped by bending a portion of the bottom edge 14 by punching. Therefore, the bottom plate 141 can be coupled by juxtaposing with one another to form an annular or circular planar area, to be in contact with the surface of a heat source.
Multiple numbers of fins 10 may be coupled in series through the latching elements 15 on the top edge 13 and the bottom edge 14 to become a chain, and then be arranged to a desired shape according to requirements. As the fins 10 are coupled in the middle portion of the top edge 13 and bottom edge 14, the angle between the fins 10 may be changed as desired without being restricted by the shape and arrangement of the latching element 15. The resulting arrangement of the fins 10 may be a linear or an annular fashion with a head end coupling with a tail end.
Referring to FIGS. 3 through 6, after the fins 10 are coupled in series in a linear fashion, the head end and the tail end may be coupled to form an annular arrangement with the fins 10 positioned radially.
In order to strengthen the coupling of the fins 10, the outer edge 12 of the fins 10 has a notch 121 to be coupled by a strapping ring 20, to form a secured fastening to prevent the fins 10 from loosening off. The strapping ring 20 is made of a copper band and has a connecting hook 21 on one end and a connecting hole 22 on another end to engage with each other, to confine the fins 10.
The inner edge 11 of the fins 10 forms a holding section 111, to hold a cylindrical spacer 30 in the center. The inner edge 11 of the fins 13 presses the peripheral surface of the cylindrical spacer 30 without jutting in a staggered manner, so that the annular shape may be maintained intact.
After the fins 10 are coupled in series in the annular fashion, the bottom plates 141 are coupled in a juxtaposed manner to form a circular or an annular plane, to be in contact directly with the surface of a heat source or coupled with a base 40 as shown in FIG. 3. The base 40 has a top surface 41 and a bottom surface 42. The bottom plates 141 of the fins 10 are in contact with the top surface 41 and bonded by soldering. The bottom plates 141 may also be coated with a thermal conductive medium and in contact with the top surface 41 while the bottom surface 42 is in contact with the heat source to transfer heat to the fins 10 for heat dissipation by convection.
To match the packaging type of the electronic chipset, the base 40 has adopted a two-stage structure. A portion abutting the top surface 41 is a circular plate to mate the circular plane of the coupled bottom plates 141 of the fins 10, while the portion adjacent to the bottom surface 42 is rectangular to mate the packaging type of the electronic chipset, so that the base 40 can conduct heat from the electronic chipset through the bottom surface 42.
In order to enable the fins 10 and the base 40 to be fixed on the electronic chipset as desired, the invention further provides a mounting frame 50 and a mounting dock 60.
The mounting plate 50 has a holding bore 51 in the center, mating the bottom surface 42 of the base 40. There is a plurality of apertures 52 around the holding bore 51. The base 40 has a plurality of screw holes 43 mating the apertures 52, to receive screws (not shown in the drawings), to fasten the base 40 on the mounting plate 50.
The mounting dock 60 is fixedly mounted onto a circuit board (not shown in the drawings). It has a bottom portion 61 with an open area in the center to hold the electronic chipset previously discussed. The mounting dock 60 is coupled with the mounting plate 50 so that the bottom surface 42 of the base 40 can be in contact with the electronic chipset, to transfer heat. To couple the mounting plate 50 with the mounting dock 60, the mounting plate 50 has a first elastic reed 53 and a second elastic reed 54 extended outwards from opposite edges. The first elastic reed 53 has a first hooking portion 531 on the end of the first hook section 531 with an opening directing upwards. The second elastic reed 54 has a hooking member 55 which has a second hook section 551 formed with an L-shape cross section and an opening directing upwards, and a horizontal bucking section 552. The second elastic reeds 53 and the second elastic reeds 54 form an angle with the mounting plate 50, and incline upwards. The mounting dock 60 has a bottom portion 61 with two side plates 62 extended upwards from opposite edges. Each of the side plates 62 has a hooking hole 621 corresponding to the first and second elastic reeds 53, 54 to be coupled with the first hook section 531 and the hooking member 55 so that the mounting plate 50 may be coupled securely on the mounting dock 60. The first and second elastic reeds 53, 54 have elasticity to hold the base 40 firmly in contact with the surface of the electronic chipset.
To couple the mounting plate 50 on the mounting dock 60, first, latch the first hook section 531 of the first elastic reed 53 in a corresponding hooking hole 621; next, press the bucking section 552 on the front end of the second elastic reed 54 to latch the second hook section 551 of the hooking member 55 in another corresponding hooking hole 621; then fasten the mounting plate 50 to the mounting dock 60 to connect the base 40 with the electronic chipset. To separate the mounting plate 50 from the mounting dock 60, remove the base 40 and the fins 10, press the bucking section 552 and move about horizontally to unlatch the second hook section 551 of the hooking member 55 from the hooking hole 621.
The invention further has a plurality of anchoring elements 71 and a fan 72. The anchoring elements 71 aim to anchor the fan 72 on the top of the fins 10 to suck in airflow or blow the airflow, to drive the cooling air, to pass over the surface of the fins 10, in order to perform cooling. As the fins 10 are arranged in an annular fashion, the entire periphery of the cooling fin assembly can ventilate air. Compared with the conventional heat sink that has the fins arranged in parallel with only two sides to pass the air, the invention has a smaller flow resistance and can increase the amount of the cooling airflow. In addition, the outer edge 12 of the fins 10 may be extended outside the base 40, so that there is a suspended space beneath the bottom edge, 14 to further facilitate air circulation.
Each of the anchoring elements 71 has two ends extended axially to form an inserting pillar 711 axially and a flange 712 vertical to the axis. The anchoring element 71 further has a plurality of axial ribs 713 to increase the strength of the anchoring element 71.
The fan 72 has an annular frame 721 with a plurality of lugs 722 extended from the periphery. Each lug 722 has an inserting hole 723 to engage with the inserting pillar 711 of the anchoring element 71 to couple the anchoring element 71 and the fan 72. The flange 712 of the anchoring element 71 presses the juncture of the outer edge 12 and bottom edge 14 of the fin 10 to anchor the fan 72 on the top edge of the fins 10. If the anchoring element 71 is shorter than the length of the outer edge 12, the outer edge 12 may have an indented portion 122 to latch with the flange 712, to form a secure anchoring.
Refer to FIG. 7 for another embodiment of the invention. Each of the fins 80 has a bottom plate 841 to form an angle with a bottom edge 84 and a latching element 85. When the fins 80 are coupled in series in an annular fashion, the bottom plates 841 are coupled in a conical fashion. The top surface 91 of the base 90 also forms a conical surface mating the bottom plates 841. Given the same diameter, the conical surface provides a larger contact area than the circular and annular plane, thus the thermal conductive coefficient of the fins 80 and the base 90 increases and the cooling effect of the cooling fin assembly improves.