Patent Publication Number: US-2012037351-A1

Title: Method for manufacturing heat sink having heat-dissipating fins and structure of the same

Description:
RELATED APPLICATIONS 
     This application is a Divisional patent application of co-pending application Ser. No. 12/073,720, filed on 10 Mar. 2008, now pending. The entire disclosure of the prior application, Ser. No. 12/073,720, from which an oath or declaration is supplied, is considered a part of the disclosure of the accompanying Divisional application and is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to a method for manufacturing a heat sink having heat-dissipating fins and a structure of the same, and in particular to a method for manufacturing a heat sink having heat-dissipating fins and a structure of the same whereby solder for welding the heat-dissipating fins can be avoided. 
     2. Description of Related Art 
     Heat sinks are widely used with heat-generating electronic elements such as CPUs or lamps (e.g. halogen lamp, LED lamp etc.), thereby facilitating heat dissipation. The heat sink having heat-dissipating fins is the most popular heat sink.  FIG. 1  shows a conventional heat sink, in which a plurality of heat-dissipating fins  13  is arranged equidistantly on the top surface  111  of a base  11  by means of soldering. 
     The heat-dissipating fins  13  are used to increase the heat-dissipating area. With the bottom surface  112  of the base  11  contacting a heat source, the base  11  absorbs the heat and transmits the heat rapidly to surfaces  131  of each heat-dissipating fin  13 , thereby facilitating the heat dissipation. 
     Since the heat-dissipating fins  13  are welded on the top surface  111  of the base  11 , and the heat transfer coefficient of the solder  12  is different from that of the base  11  or the heat-dissipating fins  13 , the solder  12  may cause some heat transfer loss when the heat is transmitted to the heat-dissipating fins  13 , which affects the heat-dissipating effect of the heat-dissipating fins  13 . Therefore, it is an important issue to develop a heat sink that is capable of dissipating the heat efficiently. 
     Consequently, because of the above technical defects, the inventor keeps on carving unflaggingly through wholehearted experience and research to develop the present invention, which can effectively improve the defects described above. 
     SUMMARY OF THE INVENTION 
     In view of the above problems, the object of the present invention is to provide a method for manufacturing a heat sink having heat-dissipating fins and a structure of the same, whereby the solder can be avoided to reduce the heat transfer loss and the heat dissipation of electronic elements can be achieved. 
     According to one aspect of the present invention, the present invention provides a method for manufacturing a heat sink having heat-dissipating fins, which includes the steps of: providing a substrate comprising a center portion and a plurality of extending arms, the center portion having a top surface, a bottom surface and side walls, the extending arms extending from the side walls of the center portion with a gap provided between each extending arm and two adjacent extending arms; providing a plurality of heat-dissipating fins, the heat-dissipating fins being inserted into the gaps between the corresponding extending arms of the substrate, each heat-dissipating fin comprising a base piece and heat-dissipating plates connected on both sides of the base piece, the two heat-dissipating plates of each heat-dissipating fin being inserted into the gaps between the corresponding extending arm and two adjacent extending arms, each heat-dissipating plate having a top end and a bottom end; and bending and pressing each extending arm of the substrate with one of the two opposite side walls of each extending arm abutting against one of the two opposite surfaces of each heat-dissipating plate, the top and bottom ends of the two heat-dissipating plates of each heat-dissipating fin protruding from the top and bottom surfaces of the substrate. 
     Alternatively, in the above-mentioned steps, two substrates that are overlapped with each other can be provided. Each extending arm of one of the substrates corresponds to each gap of the other substrate. Each heat-dissipating fin is inserted into the gap between the two corresponding extending arms of the two substrates. 
     According to another aspect of the present invention, the present invention further provides a structure of a heat sink having heat-dissipating fins, which includes: a substrate comprising a center portion and a plurality of extending arms, the center portion having a top surface, a bottom surface and two side walls, the extending arms extending from the side walls of the center portion with a gap provided between each extending arm and two adjacent extending arms; and a plurality of heat-dissipating fins each comprising a base piece and heat-dissipating plates connected on both sides of the base piece, each heat-dissipating plate having a top end and a bottom end, both heat-dissipating plates of each heat-dissipating fin being inserted into the gap between the corresponding extending arm and two adjacent extending arms, one of the two opposite side walls of each extending arm abutting against one of the two opposite surfaces of each heat-dissipating plate, the top and bottom ends of the two heat-dissipating plates of each heat-dissipating fin protruding from the top and bottom surfaces of the substrate. 
     Alternatively, two substrates can be provided and they are overlapped with each other. Each extending arm of one substrate corresponds to each gap of the other substrate. The two heat-dissipating plates of each heat-dissipating fin are inserted into the gaps between the corresponding extending arm and two adjacent extending arms of the two substrates. 
     The present invention has advantageous effects as follows. Since the heat-dissipating fins are inserted into the gaps respectively between each extending arm of the substrate, and the two side walls of each extending arm abut against and thus fix the heat-dissipating plate and the heat-dissipating fin, in comparison with the prior art of welding the heat-dissipating fins by solder, the present invention avoids the heat transfer loss caused by solder. Further, the overall manufacturing steps of the present invention are simple without increasing the difficulty in assembling and manufacturing processes. 
     Next, the top surface or bottom surface of the substrate, or one top surface or bottom surface of the two substrates can be adhered to contact heat-generating electronic elements. The top and bottom ends of each heat-dissipating plate protrude from the top and bottom surfaces of the substrate. Via this arrangement, the cooling airflow or the airflow of a heat source can be flowed into/out of the top and bottom surfaces of the substrate in two ways. In this way, the heat dissipation of the electronic elements can be achieved more easily. 
     In order to further understand the techniques, methods and effects employed by the present invention to achieve the desired objects, a detailed description relating thereto will be made with reference to the accompanying drawings. In this way, the objects, characteristics and features of the present invention can be appreciated more thoroughly. However, the drawings are illustrative only, but not used to limit the scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing a conventional heat sink; 
         FIG. 2  is a flow chart of the method of the present invention; 
         FIG. 3  is a perspective view showing the substrate of the present invention; 
         FIG. 4  is a partially exploded perspective and assembled view showing the substrate and the heat-dissipating fins of the present invention; 
         FIG. 5  is an assembled perspective view showing the substrate and the heat-dissipating fins of the present invention; 
         FIG. 6  is a front view showing the portion A of  FIG. 5 ; 
         FIG. 7  is an exploded perspective view showing the substrate of another embodiment of the present invention; 
         FIG. 8  is an exploded perspective view (I) showing the heat-dissipating fins and the substrate of another embodiment of the present invention; and 
         FIG. 9  is an exploded perspective view (II) showing the heat-dissipating fins and the substrate of another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Please refer to  FIGS. 2 to 5 . The present invention provides a method for manufacturing a heat sink having heat-dissipating fins and a structure of the same. The method includes the steps as follows. 
     (1) A substrate  2  is provided. The substrate  2  comprises a center portion  21  and a plurality of extending arms  22 . The center portion  21  has a top surface  211 , a bottom surface  212  and side walls  213 . The extending arms  22  extend from the side walls  213  of the center portion  21 . A gap  23  is provided between each extending arm  22  and two adjacent extending arms  22  respectively. 
     (2) A plurality of heat-dissipating fins  3  is provided. The heat-dissipating fins  3  are inserted into the gaps  23  between the corresponding extending arms  22  of the substrate  2  respectively. Each heat-dissipating fin  3  comprises a base piece  31  and two heat-dissipating plates  32  connected on both sides of the base piece  31 . 
     The two heat-dissipating plates  32  of each heat-dissipating fin  3  are inserted into the gaps  23  between the corresponding extending arm  22  and the two adjacent extending arms  22  respectively. Each heat-dissipating plate  32  has a top end  321  and a bottom end  322 . 
     (3) Each extending arm  22  of the substrate  2  is bent and pressed, so that one of the two opposite side walls  223  of each extending arm  22  abuts against one of the two opposite surfaces  323  of each heat-dissipating plate  32 , as shown in  FIG. 6 . At the same time, the top and bottom ends  321 ,  322  of the two heat-dissipating plates  32  of each heat-dissipating fin  3  protrude from the top and bottom surfaces  211 ,  212  of the center portion  21  of the substrate  2 . In this way, a heat sink product can be obtained. 
     In the above step (3) of bending and pressing, the free end of each extending arm  22  is bent (upwardly or downwardly, and an upward bending is shown in the present invention) toward the center portion  21 , so that each extending arm  22  is bent to point upwards or downwards from the side walls  213  of the center portion  21 . Further, each extending arm  22  is pressed in such a manner that both side wall surfaces  221  abut against the heat-dissipating plates  32  of the corresponding heat-dissipating fin  3 . In this way, each heat-dissipating fin  3  can be fixed to the side edge of the center portion  21  firmly. 
     According to the above description, the structure of the heat sink of the present invention includes the above substrate  2  and a plurality of heat-dissipating fins  3 . Each extending arm  22  of the substrate  2  is bent to extend from the side walls  213  of the center portion  21 . A gap  23  is formed between each extending arm  22  and two adjacent extending arms  22  respectively. Each heat-dissipating fin  3  is provided in the gap  23  between the corresponding extending arms  22  of the substrate  2 . One of the two side wall surfaces  221  of each extending arm  22  abuts against one of the two surfaces  323  of each heat-dissipating plate  32 . The top end  321  and the bottom end  322  of the two heat-dissipating plates  32  of each heat-dissipating fin  3  protrude from the top surface  211  and the bottom surface  212  of the substrate  2 . 
     The center portion  21  of the above substrate  2  can be a circular plate. Thus, each extending arm  22  is radially provided on the side walls  213  of the circular plate-like center portion  21 . Of course, the above center portion  21  can be a polygonal plate (such as quadrangle). The extending arms  22  are formed to extend from each side wall  213  of the center portion  21  respectively. Preferably, the center portion  21  is a circular plate. Therefore, the above step (2) of inserting the heat-dissipating fins  3  can be performed automatically, thereby achieving mass production. More specifically, each heat-dissipating fin  3  can be inserted on the substrate  2  manually in sequence. Of course, the insertion can be performed automatically, thereby achieving mass production. In addition, the substrate  2  and the heat-dissipating fins  3  can be made of the same metallic material having a heat-dissipating effect, such as copper and aluminum. 
     Please refer to  FIGS. 7 and 9 , which show another embodiment. The difference between the present embodiment and the previous embodiment lies in that: 
     (1) Two substrates  2 ,  2 ′ are provided. The two substrates  2 ,  2 ′ are overlapped with each other. Each extending arm  22 ′ of one substrate  2 ′ corresponds to each gap  23  of the other substrate  2 , so that the extending arms  22 ,  22 ′ of the two substrates  2 ,  2 ′ are arranged alternatively in the vertical direction. 
     (2) Each heat-dissipating fin  3  is inserted in the gaps  23 ,  23 ′ of the corresponding extending arms  22 ,  22 ′ of the two substrates  2 ,  2 ′. Both heat-dissipating plates  32  of each heat-dissipating fin  3  are inserted into the gaps  23 ,  23 ′ between the extending arms  22 ,  22 ′ and two adjacent extending alms  22 ,  22 ′. 
     (3) Each of the extending arms  22 ,  22 ′ of the two substrates  2 ,  2 ′ is bent and pressed, so that one of the two opposite side wall surfaces  221 ,  221 ′abuts against one of the two opposite surfaces  323  of each heat-dissipating plate  32 . 
     As shown in  FIG. 8 , in the step (3) of bending and pressing of the present embodiment, the free ends of the extending arms  22 ,  22 ′ of the two substrates  2 ,  2 ′ are bent (upwardly or downwardly) toward the two center portions  21 ,  21 ′ in the same direction. Alternatively, as shown in  FIG. 9 , the free ends of the extending arms  22 ,  22 ′ of the two substrates  2 ,  2 ′ are bent toward the two center portions  21 ,  21 ′ in opposite directions. That is to say, the free end of each extending arm  22  of one substrate  2  is opposite to the free end of each extending arm  22 ′ of the other substrate  2 ′. 
     According to the above, the structure of the heat sink of the present embodiment includes two substrates  2 ,  2 ′ that are overlapped with other and a plurality of heat-dissipating fins  3 . The extending arms  22 ,  22 ′ of each substrate  2 ,  2 ′ are bent to extend from the side walls  213 ,  213 ′ of the center portions  21 ,  21 ′. Each extending arm  22 ′ of one substrate  2 ′ corresponds to each gap  23  of the other substrate  2 . 
     Each heat-dissipating fin  3  is provided in the gaps  23 ,  23 ′ between the corresponding extending arms  22 ,  22 ′ of the two substrates  2 ,  2 ′. Two heat-dissipating plates  32  of each heat-dissipating fin  3  are inserted into the gaps  23 ,  23 ′ between the corresponding extending arms  22 ,  22 ′ and two adjacent extending arms  22 ,  22 ′. One of the two side wall surfaces  221 ,  221 ′ of each extending arm  22 ,  22 ′ abuts against one of the two opposite surfaces  323  of each heat-dissipating plate  32 . 
     In addition, the free ends of the extending arms  22 ,  22 ′ of the two substrates  2 ,  2 ′ extend in the same direction. Alternatively, the free ends of the extending arms  22 ,  22 ′ of the two substrates  2 ,  2 ′ extend in opposite directions. 
     According to the above description, in the present invention, the heat-dissipating fin  3  is inserted into the gaps  23 ,  23 ′ respectively between each extending arm  22 ,  22 ′of the substrate  2 ,  2 ′, and the two side walls  221 ,  221 ′ of each extending arm  22 ,  22 ′ abut against and thus fix the heat-dissipating plates  32  and the heat-dissipating fins  3 . In comparison with the prior art of welding the heat-dissipating fins by solder, the present invention avoids the heat transfer loss caused by solder. Further, the overall manufacturing steps of the present invention are simple without increasing the difficulty in assembling and manufacturing processes. Further, avoiding the solder conforms to the concept of environmental protection (because the solder usually contains lead, while the lead-free solder has increased cost.) 
     Next, the top surface  211  or bottom surface  212  of the substrate  2 , or one top surface  211 ′ or bottom surface  212  of the two substrates  2 ,  2 ′ can be adhered to contact heat-generating electronic elements (such as LED lamp). The top and bottom ends  321 ,  322  of each heat-dissipating plate  32  protrude from the top surfaces  211 ,  211 ′ and the bottom surfaces  212 ,  212 ′ of the substrates  2 ,  2 ′. Via this arrangement, the cooling airflow or the airflow of a heat source can be flowed into /out of the top surface  211 ,  211 ′ and the bottom surface  212 ,  212 ′ of the substrate  2 ,  2 ′ in two ways. In this way, the heat dissipation of the electronic elements can be achieved more easily. 
     While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.