Abstract:
A heat dissipation device is for dissipating heat generated from an electronic device, and includes a fan duct and a heat sink. The fan duct includes a top plate having a receiving hole penetrating therethrough. The heat sink is configured to dissipate heat from a heat-generating electronic component of the electronic device, and includes a base configured to be mounted on the heat-generating electronic component and a number of heat dissipating sheets positioned on the base. The heat dissipating sheets are long enough to extend towards the fan duct and into the receiving hole when the heat dissipation device is installed in the electronic device.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to heat dissipation technology for electronic apparatuses, and more particularly, to a heat dissipation device and an electronic device using the heat dissipation device. 
         [0003]    2. Description of Related Art 
         [0004]    Electronic devices such as servers usually employ a heat dissipation device to dissipate heat generated by multiple heat-generating electronic components including a central processing unit in the electronic device. The heat dissipation device includes heat sinks and a fan duct. The heat sinks each include a base mounted on a corresponding heat-generating electronic component, and a plurality of upright fins positioned on the base. The fan duct covers the heat sinks and the corresponding electronic components in the electronic device. The fins of the heat sinks extend towards the fan duct and keep a certain distance from the fan duct. The heat sinks are configured to have increased length of the fins along the extending direction of the fins towards the fan duct, to improve heat dissipation efficiency. However, the fin length of the heat sinks is still limited due to the blockage by the fan duct. Accordingly, it is difficult for each fin to have a large cooling surface area. 
         [0005]    What is needed, therefore, is a heat dissipation device and an electronic device using the heat dissipation device which can overcome the described limitations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the various views, and all the views are schematic. 
           [0007]      FIG. 1  is an exploded, isometric view of an electronic device according to a first embodiment of the present disclosure. 
           [0008]      FIG. 2  is a slightly enlarged, assembled view of the electronic device of  FIG. 1 , but omitting a top cover thereof. 
           [0009]      FIG. 3  is an assembled view of the electronic device of  FIG. 1 . 
           [0010]      FIG. 4  is an enlarged, cross-sectional view of a portion of the electronic device of  FIG. 3 , taken along a line IV-IV thereof. 
           [0011]      FIG. 5  is similar to  FIG. 2 , but showing an electronic device according to a second embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Reference will now be made to the drawings to describe specific exemplary embodiments of the present disclosure in detail. 
         [0013]    Referring to  FIGS. 1-2 , an electronic device  10  includes an enclosure  12 , a circuit board  13 , at least one processor, and a heat dissipation device  20 . The circuit board  13 , the at least one processor, and the heat dissipation device  20  are received in the enclosure  12 . The at least one processor is positioned on the circuit board  13  and is electrically connected to the circuit board  13 . The at least one processor may generate large amounts of heat during operation. The heat dissipation device  20  dissipates heat from the at least one processor. In the present embodiment, the at least one processor is two processors, namely a first processor  15  and a second processor  16 . The first processor  15  and the second processor  16  may be central processing units (CPUs), for example. In addition, the electronic device  10  further comprises a first memory module  27  and a second memory module  28 . The first memory module  27  and the second memory module  28  each include a memory slot (not labeled) electrically connected to the circuit board  13 , and a memory (not labeled) inserted into the memory slot. The first processor  15  and the first memory module  27  may be positioned on the circuit board  13  in alignment with each other, for example. The second processor  16  and the second memory module  28  may be positioned on the circuit board  13  in alignment with each other, for example. 
         [0014]    The enclosure  12  defines a first receiving space  129  (shown in  FIG. 2 ), which receives the circuit board  13 , the at least one processor, the first memory module  27 , the second memory module  28 , and the heat dissipation device  20  therein. The enclosure  12  includes a top cover  121 , a bottom board  120 , and a plurality of sidewalls  123  connecting the top cover  121  with the bottom board  120 . The distance between the bottom board  120  and the top cover  121  is D 1  (shown in  FIG. 4 ), which is defined as the height of the first receiving space  129 . In the illustrated embodiment, the plurality of sidewalls  123  extend from an edge of the bottom board  120 , and two opposite front and rear sidewalls  123  each include a plurality of ventilation holes  33 . 
         [0015]    The heat dissipation device  20  includes at least one heat sink and a fan duct  19 . In the present embodiment, the heat dissipation device  20  includes a first heat sink  17  and a second heat sink  18 , and the first and second heat sinks  17 ,  18  are substantially similar to each other. The first heat sink  17  is mounted on the first processor  15 . The second heat sink  18  is mounted on the second processor  16 . The first heat sink  17  dissipates the heat generated by the first processor  15 . The second heat sink  18  dissipates the heat generated by the second processor  16 . 
         [0016]    In detail, the first heat sink  17  includes a base  178  (shown in  FIG. 1 ) and a plurality of heat dissipating sheets (or plates)  170  (shown in  FIG. 2 ). The base  178  is mounted on the first processor  15 . The heat dissipating sheets  170  are perpendicular to the base  178 , and are positioned on the base  178  in parallel. Every two adjacent heat dissipating sheets  170  define a channel (not labeled) therebetween, to allow airflow to pass through. The second heat sink  18  includes a base  188  (shown in  FIG. 1 ) and a plurality of heat dissipating sheets  180  (shown in  FIG. 2 ). The base  188  is mounted on the second processor  16 . The heat dissipating sheets  180  are perpendicular to the base  188 , and are positioned on the base  188  in parallel. Every two adjacent heat dissipating sheets  180  define a channel (not labeled) therebetween, to allow airflow to pass though. The combined height of the first processor  15  and the first heat sink  17  is greater than the height of the first memory module  27 . The combined height of the second processor  16  and the second heat sink  18  is greater than the height of the second memory module  28 . 
         [0017]    Referring to  FIGS. 2-4 , the fan duct  19  is positioned between the circuit board  13  and the top cover  121 , and is fixed to the circuit board  13 . The fan duct  19  and the circuit board  13  cooperatively define a second receiving space  128 . The fan duct  19  includes a top plate  190 . The top plate  190  defines at least one receiving hole. The number of receiving hole(s) is the same as the number of heat sink(s). That is, the at least one receiving hole corresponds to the at least one processor. In the present embodiment, the at least one receiving hole is two receiving holes, namely a first receiving hole  195  and a second receiving hole  196 . The first receiving hole  195  corresponds to the first processor  15  and the first heat sink  17 . The heat dissipating sheets  170  extend towards the first receiving hole  195 , and have a shape and a size matching with a shape and a size of the first receiving hole  195 . The second receiving hole  196  corresponds to the second processor  16  and the second heat sink  18 . The heat dissipating sheets  180  extend towards the second receiving hole  196 , and have a shape and a size matching with a shape and a size of the second receiving hole  196 . 
         [0018]    When the fan duct  19  is mounted on the electronic device  10 , the heat dissipating sheets  170  extend into the first receiving hole  195 , and top surfaces  171  of the heat dissipating sheets  170  facing away from the base  178  are substantially coplanar with an upper surface  200  of the top plate  190  facing away from the base  178 . The heat dissipating sheets  180  extend into the second receiving hole  196 , and top surfaces  181  of the heat dissipating sheets  180  facing away from the base  188  are substantially coplanar with the upper surface  200  of the top plate  190 . 
         [0019]    In the present embodiment, the fan duct  19  further includes two opposite sidewalls  197  extending from two opposite edges of the top plate  190  towards the bottom board  120 . The sidewalls  197  support the top plate  190 , and each of the sidewalls  197  is mounted on one of the bottom board  120  and the circuit board  13 . In the present embodiment, both the sidewalls  197  are mounted on the circuit board  13 . In addition, a right side of the top plate  190  is fixed to a right one of the sidewalls  123  of the enclosure  12 . 
         [0020]    In other embodiments, the two opposite sidewalls  197  may be omitted. In such case, a width of the top plate  190  is configured to be substantially the same as a width of the enclosure  12 , and the top plate  190  is fixed to both of the sidewalls  197  of the enclosure  12 . 
         [0021]    The heat dissipation device  20  further includes a first fan  21  and a second fan  22 . The first fan  21  and the second fan  22  generate airflow flowing through the first and second heat sinks  17 ,  18 , to enhance heat dissipation into the surrounding air. In detail, the first and second fans  21 ,  22  are positioned on the front sidewall  123  at the ventilation holes  33  thereof. The first fan  21  faces the channels of the first heat sink  17  defined by the heat dissipating sheets  170 . The second fan  22  faces the channels of the second heat sink  18  defined by the heat dissipating sheets  180 . 
         [0022]    When the heat dissipation device  10  operates, the airflows from the first and second fans  21 ,  22  pass along the directions of the arrows shown in  FIG. 2  under the guidance of the fan duct  19 . Because ends of the heat dissipating sheets  170  of the first heat sink  17  facing away from the base  178  are received in the first receiving hole  195 , and ends of the heat dissipating sheets  180  of the second heat sink  18  facing away from the base  188  are received in the second receiving hole  196 , the first and second heat sinks  17 ,  18  are higher than comparable heat sinks completely covered by a conventional fan duct. In other words, lengths of the heat dissipating sheets  170  along the extending direction of the heat dissipating sheets  170  towards (and into) the fan duct  19  and lengths of the heat dissipating sheets  180  along the extending direction of the heat dissipating sheets  180  towards (and into) the fan duct  19  are greater than corresponding lengths of conventional heat sinks. Accordingly, cooling surface areas of the heat dissipating sheets  170 ,  180  are large, thereby enhancing the heat dissipation performance of the electronic device  10 . 
         [0023]    Referring to  FIG. 5 , in alternative embodiments, a first heat sink  30  may be higher than the first heat sink  17 , and a second heat sink  31  may be higher than the second heat sink  18 . Accordingly, the first heat sink  30  may extend (protrude) out from a first receiving hole  400  of a top plate  490  of a fan duct  40 . The second heat sink  31  may extend (protrude) out from a second receiving hole  401  of the top plate  490  of the fan duct  40 . 
         [0024]    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 present disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments.