Abstract:
A heat sink assembly ( 100 ) for cooling a heat-generating electronic component, includes a base plate ( 32 ), a plurality of fins ( 50 ) mounted on the base plate and a heat pipe ( 20 ) thermally connecting the base plate and the fins. The fins are parallel to the base plate and include a bottom fin ( 40 ) supporting the fins on the base plate. The bottom fin includes a plurality of supporting tabs ( 422 ) engaging with the base plate and separating a body ( 42 ) of the bottom fin from the base plate. The bottom fin can be used not only for dissipating heat into a surrounding environment but also for reinforcing the whole strength of the heat sink assembly.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a heat sink assembly having a plurality of fins, wherein at least one fin functions as a supporting bracket to reinforce the whole strength of the heat sink assembly. 
         [0003]    2. Description of related art 
         [0004]    Nowadays, numerous heat sinks are used to dissipate heat generated by electronic devices. A tower type heat sink is a common structure of the heat sinks. The tower type heat sink generally comprises a base, a plurality of fins parallel to the base and a heat pipe thermally connecting the base and the fins. The heat sink has a relatively high height. Thus, the heat sink is prone to becoming deformed when subjected to shock or vibration during transportation or use. 
         [0005]    Thus, it is desired to devise a heat sink which has a strengthened structure to improve deformation-resistance thereof. 
       SUMMARY OF THE INVENTION 
       [0006]    According to a preferred embodiment of the present invention, a heat sink assembly for cooling a heat-generating electronic component includes a base plate, a plurality of fins mounted on the base plate and a heat pipe thermally connecting the base plate and the fins. The fins are parallel to the base plate and include a bottom fin supporting the fins on the base plate. The bottom fin includes a plurality of supporting tabs extending downwards therefrom to engage with the base plate. The bottom fin functions not only for dissipating heat into a surrounding environment but also for reinforcing the whole strength of the heat sink assembly. 
         [0007]    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 
         [0008]    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. 
           [0009]      FIG. 1  is an assembled view of a heat sink assembly in accordance with a preferred embodiment of the present invention; 
           [0010]      FIG. 2  is an exploded view of the heat sink assembly of  FIG. 1 ; 
           [0011]      FIG. 3  is an enlarged isometric view of a seat of the heat sink assembly of  FIG. 2 ; 
           [0012]      FIG. 4  is an enlarged isometric view of the seat of the heat sink assembly of  FIG. 3 , but shown from a bottom aspect; 
           [0013]      FIG. 5  is an assembled view of a heat sink assembly in accordance with a second embodiment of the present invention; and 
           [0014]      FIG. 6  is an exploded view of the heat sink assembly of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]      FIGS. 1-2  show a heat sink assembly  100  in accordance with a preferred embodiment of the present invention. The heat sink assembly  100  is to be mounted on a printed circuit board (not shown) for dissipating heat generated by an electronic device (not shown) attached on the printed circuit board. 
         [0016]    The heat sink assembly  100  comprises a heat spreader  10  adapted for contacting with the electronic device, a pair of heat pipes  20 , a seat  30 , a supporting bracket  40  and a fin assembly  50 . The heat pipes  20  thermally connect the heat spreader  10 , the seat  30 , the supporting bracket  40  and the fin assembly  50 . 
         [0017]    The heat spreader  10  has a bottom face (not labeled) for contacting the electronic device mounted on the printed circuit board to absorb heat therefrom, and a top face  12  with a pair of parallel and adjoining grooves  120 . 
         [0018]    Each heat pipe  20  comprises a horizontal evaporating portion  22  and a vertical condensing portion  24  arranged in such a manner that the heat pipe  20  has an L-shaped configuration. The condensing portion  24  extends perpendicularly from one of free ends of the evaporating portion  22 . The evaporating portions  22  of the heat pipes  20  are soldered in the grooves  120  of the heat spreader  10 . The condensing portions  24  are located at opposite lateral sides of the heat spreader  10 , and extend through the seat  30 , the supporting bracket  40  and the fin assembly  50 . 
         [0019]    Also referring to  FIGS. 3-4 , the seat  30  comprises a base plate  32 , a connecting element  31  and a protecting element  33  attached to the base plate  32 . A temperature sensor  60  (shown in  FIG. 2 ) is mounted between the connecting element  31  and the protecting element  33 , for controlling a speed of a fan (not shown) mounted on the heat sink assembly  100 . The base plate  32  has a rectangular configuration and is made of metallic material, such as aluminum. Four poles  320  extend downwardly from four corners of the base plate  32 , for providing passage for corresponding fasteners  70  to mount the seat  30  on the printed circuit board. A rectangular through slot  321  is defined in a central portion of the base plate  32  for receiving the connecting element  31  therein. A pair of openings  322  are defined at both flanks of the slot  321  for receiving the evaporating portions  22  and curved portions (not labeled) of the heat pipes  20 . Two beams  323 ,  324  are formed between the slot  321  and the openings  322 . The beam  324  defines a V-shaped slot  3242  at a top thereof for providing passage for a signal wire of the sensor  60 . Each of the beams  323 ,  324  defines a pair of adjoining semicircular grooves  3230 ,  3240  at a bottom thereof. The heat spreader  10  is mounted on a bottom of the two beams  323 ,  324 . The semicircular grooves  120  of the heat spreader  10  are in vertical alignment with the semicircular grooves  3230 ,  3240  of the beams  323 ,  324 . Four bars  325  are formed on the bottom of the base plate  32 , for preventing movement of the heat spreader  10  relative to the base plate  32  of the seat  30 . 
         [0020]    The connecting element  31  is received in the slot  321  of the base plate  32 . The connecting element  31  defines a pair of semicircular grooves  310  horizontally in alignment with the grooves  3230 ,  3240  of the base plate  32 . These grooves  310 ,  3230 ,  3240  and the grooves  120  of the heat spreader  10  cooperatively define a pair of channels (not labeled) for receiving the evaporating portions  22  of the heat pipes  20  therein. The connecting element  31  defines a V-shaped slot  312  at a top portion thereof horizontally in alignment with the slot  3242  of the beam  324  of the base plate  32 . 
         [0021]    The protecting element  33  is mounted on the base plate  32  and engages with the connecting element  31 . The protecting element  33  has a rectangular configuration and defines a rectangular receiving space  330  defined by four sidewalls  332  of the protecting element  33 . The receiving space  330  and the V-shaped slot  312  of the connecting element  31  cooperatively receiving the sensor  60  therein. A cutout  334  is defined at a bottom edge of one of the sidewalls  322  of the protecting element  33  for facilitating passage of the signal wire of the sensor  60 . 
         [0022]    Referring to  FIG. 2  again, the fin assembly  50  comprises a plurality of fins each having a flat body  52  parallel to the base plate  32 . The bodies  52  of the fins are perforated with through holes  520 . Each of the through holes  520  has its respective annular sidewall  522  that is formed during punching. The condensing portions  24  of the heat pipes  20  are received in the through holes  520  and soldered to the sidewalls  522  so that the fin assembly  50  are combined with the condensing portions  24  of the heat pipes  20 . The fin assembly  50  has a bottom fin functioning as the supporting bracket  40 . The supporting bracket  40  supports the fin assembly  50  on the base plate  32  of the seat  30  and reinforces the whole strength of the fin assembly  50 , in addition to its original function of heat dissipation. 
         [0023]    The supporting bracket  40  also has a body  42  with a configuration similar to that of each of the bodies  52  of the fins. A pair of opposite sidewalls  420  extend perpendicularly and downwardly from front and rear edges of the body  42 . A pair of connecting walls  421  are bent inwards and horizontally from edges of the sidewalls  420 . A pair of L-shaped supporting tabs  422  respectively extend downwardly and vertically from an edge of each connecting wall  421 . The two pairs of supporting tabs  422  are located at opposite ends of the body  42 . A flat engaging portion  4220  is formed horizontally and inwardly at a free end of each supporting tab  422  for engaging with a top surface of the base plate  32 . 
         [0024]    In assembly of the preferred embodiment of the present invention, the evaporating portions  22  of the heat pipes  20  are received in the bottom of the base plate  32  after the connecting element  31  is mounted on the base plate  32  of the seat  30 . The heat spreader  10  is attached on the bottom of the base plate  32  and engages with the evaporating portions  22  of the heat pipes  20 . The protecting element  33  covers the connecting element  31  after the sensor  60  is received in the connecting element  31 . The supporting bracket  40  and the fin assembly  50  are mounted on the base plate  32  of the seat  30  in series. The condensing portions  24  are extended through the supporting bracket  40  and the fin assembly  50  simultaneously. Thus, the heat sink assembly  100  is assembled together. 
         [0025]    Referring to  FIGS. 5-6 , a heat sink assembly  100   a  according to a second embodiment of the present invention is shown. The heat sink assembly  100   a  in the second embodiment comprises a base plate  10   a,  a heat pipe  20   a,  a fixing block  60   a,  a supporting bracket  40   a  and a fin assembly  50   a.  The heat pipe  20   a  thermally connects the base plate  10   a,  the fixing block  60   a,  the supporting bracket  40   a  and the fin assembly  50   a.    
         [0026]    The base plate  10   a  has a square body  11   a.  Four ears  12   a  extend horizontally from a center of each sidewall of the body  11   a.  Four corresponding fasteners  70   a  extend through the four ears  12   a  for mounting the heat sink assembly  100   a  onto a printed circuit board (not shown). An arced slot  110   a  and a rectangular slot  112   a  are defined crossing in the body  11   a.  The slots  110   a,    112   a  are both defined at a central portion of the body  11   a.  The slot  110   a  is deeper than the slot  112   a.    
         [0027]    The heat pipe  20   a  comprises an arced evaporating portion  22   a  and a pair of vertical condensing portions  24   a  perpendicularly extending from two opposite ends of the evaporating portion  22   a.  The evaporating portion  22   a  of the heat pipe  20   a  is received in the slot  110   a  of the base plate  10   a.  The fixing block  60   a  is received in the slot  112   a  of the base plate  10   a.  A pair of rivets  62   a  extend through the fixing block  60   a  and engage in the base plate  10   a  to mount the fixing block  60   a  onto the evaporating portion  22   a  of the heat pipe  20   a.    
         [0028]    The fin assembly  50   a  comprises a plurality of fins each having a flat body  52   a  parallel to the base plate  10   a.  Each flat body  52   a  is perforated with a pair of through holes  520   a.  The condensing portions  24   a  of the heat pipe  20   a  are soldered in the through holes  520   a  so that the fins are joined with the heat pipes  20   a.  The fin assembly  50   a  has a bottom fin functioning as the supporting bracket  40   a  to support the fin assembly  50  on the base plate  10   a  and reinforce the strength of the fin assembly  50   a.  The supporting bracket  40   a  has a portion corresponding to and vertically in alignment with each body  52   a  of the fin assembly  50   a,  and another portion extending beyond the body  52   a.  The supporting bracket  40   a  has a top surface  42   a  parallel to each body  52   a  of the fin assembly  50   a.  A pair of spaced through holes  420   a  are defined at the top surface  42   a  of the supporting bracket  40   a  and vertically in alignment with the through holes  520  of the fin assembly  50   a.  The top surface  42   a  of the supporting bracket  40   a  is stamped downwardly to form a pair of U-shaped supporting tabs  422   a  located below the top surface  42   a.  The supporting tabs  422   a  traverse between the two condensing portions  24   a  of the heat pipes  20   a.  Each U-shaped supporting tabs  422   a  defines a corresponding U-shaped recess  44   a.  Each of the supporting tabs  422   a  comprises a flat engaging portion  4220   a  engaging with a top surface of the base plate  10   a.    
         [0029]    In the present invention, by the provision of the supporting brackets  40 ,  40   a  formed by the bottom fin of the fin assembly  50 ,  50   a,  the fin assembly  50 ,  50   a  can be firmly mounted to the base plate  30 /base plate  10   a.  Thus, strength of the heat sink assembly is increased. 
         [0030]    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.