Abstract:
A heat sink assembly for a heat-generating electronic component includes a base ( 12 ), a shell mounted on the base, and a plurality of heat exchangers ( 11, 13, 15 ) mounted on the base and surrounded by the shell. The heat exchangers comprise heat conducting plates ( 110,130, 150 ) extending from the base, cores ( 112, 132, 152 ) formed on tops of the heat conducting plates and a plurality of fins ( 114, 134, 154 ) arranged about the cores. A plurality of heat pipes ( 20 ) connects the base and the cores of the heat exchangers for transferring heat from the base to the fins for dissipation.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention generally relates to cooling devices such as heat exchangers and, particularly, to a heat sink assembly having heat pipes for cooling heat-generating electronic components. 
         [0003]    2. Description of Related Art 
         [0004]    In various industries, such as in the computer industry, there is a need for low cost, high performance heat exchangers to cool heat-generating electronic components such as microprocessors or power chips. Many microprocessors/power chips create so much heat that they can be irreparably damaged if the heat is not removed. Consequently, heat exchangers employing heat sinks have been used to absorb the heat away from these components and disperse the heat into the atmosphere. The present invention is directed to improvements in such heat sink assemblies. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention relates to a heat sink assembly for a heat-generating electronic component. The heat sink assembly includes a base, a shell mounted on the base, and a plurality of heat exchangers mounted on the base and surrounded by the shell. The heat exchangers comprise heat conducting plates extending from the base, cores formed on tops of the heat conducting plates and a plurality of fins extending radially and curvedly from the cores. A plurality of heat pipes connects the base and the cores of the heat exchangers for transferring heat from the base to the fins for dissipation of the heat to atmosphere. 
         [0006]    Other advantages and novel features of the present invention will become more apparent from the following detailed description of preferred embodiment when taken in conjunction with the accompanying drawings, in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Many aspects of the present device 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 device. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0008]      FIG. 1  is an assembled view of a heat sink assembly in accordance with a preferred embodiment of the present invention; 
           [0009]      FIG. 2  is an exploded, isometric view of the heat sink assembly of  FIG. 1 ; 
           [0010]      FIG. 3  is an isometric view of a heat sink of the heat sink assembly of  FIG. 1 , but shown from another aspect; and 
           [0011]      FIG. 4  is a front view of the heat sink of the heat sink assembly of  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]    Referring to  FIGS. 1-2 , a heat sink assembly in accordance with a preferred embodiment of the present invention is used for being mounted to a heat-generating electronic element, such a CPU (not shown), to dissipate heat therefrom. The heat sink assembly comprises an integral heat sink  10  and a heat pipe assembly  20  assembled to the heat sink  10 . 
         [0013]    The heat sink  10  is integrally formed by aluminum extrusion and has a base  12 . A protrusion block  120  is formed on a bottom surface of the base  12  for contacting with the CPU. The block  120  defines three grooves  1202  therein. Four ears  123  extend outwardly and horizontally from corners of the base  12  and provide passages (not labeled) for fasteners (not shown) to extend therethrough to mount the heat sink assembly on the CPU which is mounted on a printed circuit board (not shown). A pair of lateral plates  14  extend perpendicularly upwardly from a top surface of the base  12 . An arched cover  16  connects the two plates  14  at middle portions thereof, whereby a C-shaped shell (not labeled) is formed by the cover  16  and lower portions of the plates  14 . Also referring to  FIG. 4 , a top edge of the cover  16  is in alignment (i.e., the same level) with top edges of the plates  14 . Three heat exchangers  11 ,  13 ,  15  are formed from the base  12  and received in a space  122  defined by the C-shaped shell. The space  122  has two opposite open ends. 
         [0014]    Also referring to  FIG. 3 , each of the heat exchangers  11 ,  13 ,  15  comprises a heat conducting plate  110 ,  130 ,  150  extending upwardly from the base  12 , a cylindrical core  112 ,  132 ,  152  formed on a top of the heat conducting plate  110 ,  130 ,  150  and a set of curved fins  114 ,  134 ,  154  arranged about the core  112 ,  132 ,  152 . Each heat conducting plate  110 ,  130 ,  150  extends through the space  122  of the heat sink  10  from a front open end to a rear open end thereof. The heat conducting plate  110  is located perpendicularly at a center of the base  12 , and the heat conducting plates  130 ,  150  are slantwise, symmetrically arranged at flanks of the heat conducting plate  110  in such a manner that two neighboring heat conducting plates  110 ,  130  and  110 ,  150  form an acute included angle therebetween. The heat conducting plates  130 ,  150  have the same height which is shorter than that of the heat conducting plate  110 . The core  112  of the heat exchanger  11  is located above the cores  132 ,  152  of the heat exchangers  13 ,  15 . Each of the cores  112 ,  132 ,  152  has a central axle (not labeled) parallel to each other and defines a central cavity  1120 ,  1320 ,  1520  for insertion of the heat pipe assembly  20 . The sets of fins  114 ,  134 ,  154  are radially and curvedly extended outwards from the cores  112 ,  132 ,  152  of the heat exchangers  11 ,  13 ,  15 , respectively. The sets of fins  114 ,  134 ,  154  are curved in their respective similar directions. The set of fins  134  of the heat exchanger  13  and the set of fins  154  of the heat exchanger  15  are symmetrical and mirror image about the heat conducting plate  110  of the heat exchanger  11 , which means that the fins  134  are curved in a clockwise direction while the fins  154  are curved in an anti-clockwise direction. The fins  114  are located above the fins  134 ,  154 . The fins  114  are partly cut away to prevent the fins  114  from interfering with the fins  134 ,  154 . An outer periphery surface of each set of fins  114 ,  134 ,  154  is substantially arranged in a cylindrical outline. 
         [0015]    Referring to  FIG. 2  again, the heat pipe assembly  20  comprises a first heat pipe  21  and a pair of second heat pipes  22  symmetrically slantwise arranged at flanks of the first heat pipe  21 . Each of the first and second heat pipes  21 ,  22  has a U-shaped configuration and comprises an evaporating portion  210 ,  220  received in the corresponding groove  1202  of the base  12  of the heat sink  10 , and a condensing portion  212 ,  222 , parallel to the evaporating portion  210 ,  220  and engaged in the corresponding cavity  1120 ,  1320 ,  1520  of the heat exchanger  11 ,  13 ,  15 . The evaporating portions  210 ,  220  of the first and second heat pipes  21 ,  22  have flat bottoms in order to directly contact with the CPU. A perpendicular distance between the evaporating portion  210  and the condensing portion  212  of the first heat pipe  21  is larger than a perpendicular distance between the evaporating portion  220  and the condensing portion  222  of the second heat pipe  22 . 
         [0016]    In addition to the integral extrusion of aluminum, alternatively, the heat sink  10  in accordance with the present invention may be made by firstly forming the heat exchangers  11 ,  13 ,  15  individually, and then soldering the heat exchangers  11 ,  13 ,  15  onto the base  12 . 
         [0017]    In operation, heat generated by the CPU is absorbed by the base  10  and the evaporating portions  210 ,  220  of the heat pipe assembly  20 , and immediately and simultaneously transferred to the cores  112 ,  132 ,  152  of the three heat exchangers  11 ,  12 ,  13  via the condensing portions  212 ,  222  of the heat pipe assembly  20  and the heat conducting plates  110 ,  130 ,  150  of the heat exchangers  11 ,  12 ,  13 . The heat on the cores  112 ,  132 ,  152  is subsequently transferred to the fins  114 ,  134 ,  154  of the heat exchangers  11 ,  13 ,  15  for being dissipated to atmosphere. A system fan (not shown) provides an airflow though the fins  114 ,  134 ,  154 , thereby enhancing a rate of heat dissipation. The shell of the heat sink  10  prevents the airflow flowing through the space  122  from leaving therefrom. Accordingly, the airflow flowing through the space  122  can have a sufficient heat exchange with the heat exchangers  11 ,  13 ,  15 ; thus, heat received by the heat exchangers  11 ,  13 ,  15  from the CPU via the heat pipe assembly  20  and the heat conducting plates  110 ,  130 ,  150  can be quickly and efficiently dissipated to atmosphere by the airflow. 
         [0018]    It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.