Abstract:
A heat dissipation device includes a heat sink and a heat pipe extending through the heat sink. The heat sink includes a plurality of fins overlapped with each other. An air passage channel is defined between every two adjacent fins for an airflow flowing therethrough. Each of the fins defines a through hole therein for extension of the heat pipe. Each of the fins includes a main plate and an air guiding member formed on the main plate. The air guiding member includes a curved bar. The curved bar extends slantwise on the main plate to a back side of the heat pipe for guiding the airflow to the back side of the heat pipe.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to heat dissipation devices, and more particularly to a heat dissipation device for dissipating heat generated by electronic components of computers. 
         [0003]    2. Description of Related Art 
         [0004]    With the development of the electronic technology, some electronic components, for example, central processing units (CPUs), operate at faster and faster speeds, which causes the electronic components to generate redundant heat. If the heat is not quickly removed from the electronic components, stable and fast performances of the electronic components will not be sustained. Usually, people in the art install a heat dissipation device on a electronic component to help dissipating the heat of the electronic component. 
         [0005]    A typical heat dissipation device includes a heat sink, a heat pipe extending through the heat sink, and a fan mounted on the heat sink. The heat sink includes a plurality of plate-shaped metallic fins overlapped with each other at a constant interval. An air passage channel is defined between every two adjacent fins. Each of the fins defines a through hole therein. The heat pipe includes an evaporation section and a condensation section at two opposite end thereof. The evaporation section of the heat pipe is thermally contacted with the electronic component to absorb heat therefrom, and the condensation section of the heat pipe runs through the through holes of the fins. 
         [0006]    During operation, the heat of the electronic component is transferred from the evaporation section of the heat pipe to the condensation of the heat pipe, and then transferred to the fins of the heat sink. The fan is configured to generate an airflow which flows through the air passage channels of the heat sink to take away the heat of the fins. However, when the airflow flows through the air passage channels of the heat sink, the airflow can not reach a leeward side of the condensation section of the heat pipe because the airflow is blocked by the condensation section. A hot swirl is accordingly formed at the leeward side of the condensation section of the heat pipe. Thus, a portion of the fins at the leeward side of the condensation section of the heat pipe cannot exchange heat efficiently and adequately with the airflow of the fan, causing a relatively high temperature occurred at the leeward side of the condensation section. As a result, the heat dissipation efficiency of the heat dissipation device is decreased. 
         [0007]    What is desired, therefore, is a heat dissipation device which can overcome the above described shortcomings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an exploded, isometric view of a heat dissipation device in accordance with an embodiment of the present disclosure. 
           [0009]      FIG. 2  is an assembled, isometric view of the heat dissipation device of  FIG. 1 . 
           [0010]      FIG. 3  is a schematic view of an airflow directions on a fin of the heat dissipation device. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    Reference will now be made to the drawing figures to describe the present disclosure in detail. 
         [0012]    Referring to  FIGS. 1-2 , a heat dissipation device  10  in accordance with an embodiment of the present disclosure is shown. The heat dissipation device  10  includes a heat absorbing plate  12 , a first heat sink  14  above the heat absorbing plate  12 , a second heat sink  16  above the first heat sink  14 , and two heat pipes  18  thermally connecting the heat absorbing plate  12  and the second heat sink  16 . The first heat sink  14  is located between the second heat sink  16  and the heat absorbing plate  12  and thermally connects to the heat absorbing plate  12  and the heat pipes  18 . 
         [0013]    The heat absorbing plate  12  has a rectangular plate-shaped profile and is provided with a flat lower surface  120  and a flat upper surface  122  opposite to the lower surface  120 . The upper surface  122  defines two grooves  123  therein. The two grooves  123  are parallel to each other and extend between two opposite lateral sides of the upper surface  122  of the heat absorbing plate  12 . In this embodiment, each of the grooves  123  extends from a left lateral side of the upper surface  122  to a right lateral side of the upper surface  122 . 
         [0014]    The first heat sink  14  is attached on the upper surface  122  of the heat absorbing plate  12 . The first heat sink  14  includes a base plate  140  and a plurality of first fins  142  extending upwardly and perpendicularly from the base plate  140 . The base plate  140  is rectangular and plate-shaped, and has a size larger than that of the heat absorbing plate  12 . The base plate  140  defines two pairs of first through holes  143  therein, wherein one pair of the through holes  143  is located above the left side of the heat absorbing plate  12  and the other pair of the through holes  143  is located above the right side of the heat absorbing plate  12 . 
         [0015]    The second heat sink  16  is positioned above the first heat sink  14  and includes a plurality of second fins  160  stacked together along a bottom-to-up direction. The second fins  160  are plate-shaped and parallel to each other. The second fins  160  are parallel to the heat absorbing plate  12  and the base plate  140  of the first heat sink  14 . An air passage channel  162  is defined between every two adjacent second fins  160 . Each of the second fins  160  includes a main plate  161  and an air guiding member  163  formed at a middle portion of the main plate  161 . The main plate  161  is rectangular and defines two pairs of second through holes  164  therein. Each pair of second through holes  164  of the second fins  160  are aligned with a corresponding pair of first through holes  143  of the base plate  140  of the first heat sink  14 . The air guiding member  163  is located between the two pairs of second through holes  164  of the main plate  161 , and protrudes upwardly and perpendicularly from the main plate  161 . A height that the air guiding member  163  protrudes up from the main plate  161  of one fin  160  is less than a width of the air passage channel  162 , whereby a top of the air guide member  163  is spaced a little from an adjacent above fin  160 . The air guiding member  163  is substantially triangular in shape, and includes a straight bar  165  and two curved bars  167 . The straight bar  165  and the two curved bars  167  are connected with each other end to end to form a triangular ring. The straight bar  165  is located at a back side of the two pair of second through holes  164  and extends along the main plate  161  from a position adjacent to one pair of the second through holes  164  to a position near the other pair of the second through holes  164 . The two curved bars  167  are symmetric about a midline between the two pair of second through holes  164 . Each of the two curved bars  167  includes a windward end  1671  and a leeward end  1672  at two opposite ends thereof. Each of the two curved bars  167  faces a corresponding pair of second through holes  164 . The windward ends  1671  of the two curved bars  167  intersect at a middle of the second fin  160 . The leeward ends  1672  of the two curved bars  167  extend to the back side of the two pair of second through holes  164  and respectively intersect with two opposite ends of the straight bar  165 . 
         [0016]    The two heat pipes  18  are substantially U-shaped. Each of the two heat pipes  18  includes an evaporation section  180  and two condensation sections  182  extending upwardly and perpendicularly from two opposite ends of the evaporation section  180 . 
         [0017]    In assembly of the heat dissipation device  10 , the evaporation sections  180  of the two heat pipes  18  are respectively received in the two grooves  123  of the heat absorbing plate  12 , and the condensation sections  182  of the two heat pipes  18  protrude upwardly. The first heat sink  14  is then placed on the heat absorbing plate  12  with the base plate  140  thereof attached on the upper surface  122  of the heat absorbing plate  12 . The condensation sections  182  of the two heat pipes  18  extend respectively through the two pairs of first through holes  143  of the first heat sink  14 . The second heat sink  16  is then placed on the first heat sink  14 , and the condensation sections  182  of the two heat pipes  18  extend respectively into the two pairs of second through holes  164  of the second heat sink  16 . 
         [0018]    Referring to  FIG. 3 , in use, an airflow (designated by the arrows) generated by a fan (not shown) flows along a direction from the windward ends  1671  of the two curved bars  167  to the leeward ends  1672  of the two curved bars  167 . A portion of the airflow directly flows through the air passage channels  162  of the second heat sink  16  and the first heat sink  14  to take away the heat of the heat dissipation device  10 . Another portion of the airflow is guided by the curved bars  167  to flow from the windward ends  1671  to the leeward ends  1672  of the curved bars  167 , such that the airflow is guided to a leeward side of the condensation sections  182  of the heat pipes  18 , whereby the portion of the second fins  16  behind the leeward side of the condensation sections  182  of the heat pipes  16  can be quickly cooled, and accordingly, the hot swirl behind the leeward side of the condensation sections  182  of the heat pipes  18  is thus eliminated. 
         [0019]    In the present heat dissipation device  10 , the straight bar  165  of the air guiding member  163  is located at a leeward side of the airflow and perpendicular to a flow direction of the airflow. The two curved bars  167  are located in the middle portion of each second fin  160  and disposed between the condensation sections  182  of the heat pipes  18 . The windward ends  1671  of the two curved bars  167  are converged at a windward side of the airflow. The two curved bars  167  expand outwardly from the windward side towards the leeward side of the airflow and the leeward ends  1672  of the curved bars  167  are respectively connected to the opposite ends of the straight bar  165 . As a result, the airflow can be guided smoothly by the curved bars  167  of the air guiding member  163  to the back side of the condensation sections  182  of the heat pipes  18 . A heat dissipation efficiency of the heat dissipation device  10  is thus greatly increased. 
         [0020]    It is to be understood, however, that even though numerous characteristics and advantages of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of the embodiments, 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 disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.