Patent Publication Number: US-2011048679-A1

Title: Heat dissipation device

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to heat dissipation apparatuses, and particularly to a heat dissipation apparatus for dissipating heat generated by electronic components. 
     2. Description of Related Art 
     It is widely acknowledged that heat is produced during operation of electronic components such as central processing units (CPUs) of computers. The heat produced by an electronic component must be quickly removed to protect the electronic component. Typically, a heat dissipation apparatus is provided to remove heat from the electronic component. The heat dissipation apparatus includes a heat pipe and a plurality of fins stacked together. One end of the heat pipe thermally connects with the electronic component, while the other end of the heat pipe connects with the fins. Heat generated by the electronic component is transferred to the fins via the heat pipe. Generally, the heat pipe and the fins are jointed together by soldering. Thus, the soldering quality directly and significantly affects a heat transfer efficiency between the heat pipe and the fins. 
       FIGS. 1 and 2  show a conventional heat dissipation apparatus  100 . The conventional heat dissipation apparatus  100  includes a flat heat pipe  11  and a plurality of fins  12 . Each fin  12  defines an elongated receiving hole  121  therein for receiving the flat heat pipe  11  and an accommodating hole  122  therein communicating with the receiving hole  121  for accommodating a solder paste  13 . The accommodating hole  122  is located above the receiving hole  121  and at a center of a top edge of the receiving hole  121 . A collar  123  extends vertically from a periphery of the receiving hole  121  and a periphery of the accommodating hole  122  of the fin  12 . 
     Referring to  FIG. 1 , the flat heat pipe  11  is inserted in the receiving holes  121  of the fins  12 . A clearance exists between the flat heat pipe  11  and the collar  123  of each fin  12  before the flat heat pipe  11  and the fins  12  being soldered together. The solder paste  13  is accommodated in the accommodating hole  122  of each fin  12 . When soldering, the solder paste  13  is heated to its melting point. The molten solder paste  13  flows from the accommodating hole  122  into the receiving hole  121  of each fin  12  to fill up the clearance between the flat heat pipe  11  and the collar  123  of each fin  12 . Referring to  FIG. 2 , after the molten solder paste  13  is cooled, a solder layer  14  is formed between the flat heat pipe  11  and the collar  123  of each fin  12 , combining the flat heat pipe  11  and the fins  12  together. 
     However, in the above-mentioned heat dissipation apparatus  100 , due to the accommodating hole  122  being located at a center of the top edge of the receiving hole  121 , a flow distance of the molten solder from the accommodating hole  122  to a center point of a bottom edge of the receiving hole  121  is so longer that the molten solder paste can not fully fill up a clearance between a bottom planar face of the flat heat pipe  11  and a bottom planar plate of the collar  123 . Thus, insufficient solder easily occurs between the bottom planar face of the flat heat pipe  11  and the bottom planar plate of the collar  123 , which reduces the heat transfer efficiency between the flat heat pipe  11  and the fins  12 . In addition, an effective contacting surface of the flat heat pipe  11  for combining with the collars  123  of the fin  12  includes both of the top and bottom planar faces of the flat heat pipe  11 . The accommodating hole  122  at a center of the top edge of the receiving hole  121  reduces the effective contacting area of the flat heat pipe  11  for combining with the collars  123  of the fins  12 . 
     For the foregoing reasons, therefore, there is a need in the art for a heat dissipation apparatus which overcomes the limitations described. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present embodiment 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 embodiment. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is a cross-sectional view of a conventional heat dissipation apparatus, showing a state before a flat heat pipe and fins thereof are soldered together. 
         FIG. 2  is similar to  FIG. 1 , but showing a situation after the flat heat pipe and the fins of the heat dissipation apparatus have been soldered together. 
         FIG. 3  is an isometric view of a heat dissipation apparatus in accordance with a first embodiment, with a fin thereof being separated therefrom for a better illustration. 
         FIG. 4  is a cross-sectional view of the heat dissipation apparatus of  FIG. 3 , showing a state before a flat heat pipe and fins thereof are soldered together. 
         FIG. 5  is similar to  FIG. 4 , but showing a state after the flat heat pipe and the fins of the heat dissipation apparatus have been soldered together. 
         FIG. 6  is a cross-sectional view of a heat dissipation apparatus in accordance with a second embodiment. 
         FIG. 7  is a cross-sectional view of a heat dissipation apparatus in accordance with a third embodiment, showing a state before a flat heat pipe and fins thereof are soldered together. 
         FIG. 8  is similar to  FIG. 7 , but showing a state after the flat heat pipe and the fins of the heat dissipation apparatus have been soldered together. 
         FIG. 9  is a cross-sectional view of a heat dissipation apparatus in accordance with a fourth embodiment. 
         FIG. 10  is a cross-sectional view of a heat dissipation apparatus in accordance with a fifth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 3 , a heat dissipation apparatus  200  according to a first embodiment includes a flat heat pipe  21  and a plurality of fins  22  stacked together. The flat heat pipe  21  has an L-shaped configuration. The flat heat pipe  21  includes an evaporator section  211  used for thermally connecting with an electronic component (not shown), and a condenser section  212  thermally connecting with the fins  22  to transfer heat therebetween. 
     Referring also to  FIGS. 4 and 5 , an outer surface of the flat heat pipe  21  includes a top planar face  213 , a bottom planar face  214  opposite and parallel to the top planar face  213 , and two curved faces  215  respectively located at two opposite sides of the flat heat pipe  21  and connected between the top planar face  213  and the bottom planar face  214 . 
     Each fin  22  includes a main body  221  and two flanges  222  bending from top and bottom ends of the main body  221 . The fin  22  defines an elongated receiving hole  223  therein for receiving the condenser section  212  of the flat heat pipe  21 . The receiving hole  223  is substantially rectangular-shaped, with straight, parallel top and bottom sides, an arced right side, a straight left side with an arced bottom, left corner between the left side and the bottom side. The fin  22  further defines a small-sized, substantially semicircular accommodating hole  224  therein for accommodating a solder paste  23 . The accommodating hole  224  is located a top, left corner of the receiving hole  223  and communicates with the receiving hole  223 . 
     A combining sidewall  24  extends vertically from an edge of the receiving hole  223  of the fin  22 . The combining sidewall  24  includes an elongated top planar plate  241 , an elongated bottom planar plate  242  opposite to the top planar plate  241 , a left short plate  243  at a left side of the receiving hole  223 , and a right short plate  244  at a right side of the receiving hole  233 . The left short plate  243  extend substantially straight from a left end of the bottom planar plate  242  towards a left end of the top planar plate  241 , while the right short plate  244  extend curvedly from a right end of the bottom planar plate  242  to a right end of the top planar plate  241 . The accommodating hole  224  is located at the left end of the top planar plate  241  and a top end of the left short plate  243 . In other words, the accommodating hole  224  is located at a junction of the top planar plate  241  and the left short plate  243 . The accommodating hole  224  extends along a width direction of the receiving hole  223  and is located above the receiving hole  233 . A combining plate  245  extends vertically from an edge of the accommodating hole  224  of the fin. The combining plate  245  is connected between the left end of the top planar plate  241  and the top end of the left short plate  243  of the combining sidewall  24 . A top end of the right short plate  244  connects with a right end of the top planar plate  241 . Thus, the combining plate  245  and the combining sidewall  24  cooperatively form a closed wall enclosing the receiving hole  223  and the accommodating hole  224 . 
     Referring to  FIG. 4 , the flat heat pipe  21  is inserted in the receiving holes  224  of the fins  22 . A clearance exists between the outer surface of the flat heat pipe  21  and the combining sidewall  24  of each fin  22  before the flat heat pipe  21  and the fins  22  being soldered together. The solder paste  23  is accommodated in the accommodating hole  224  of each fin  22 . When soldering, the solder paste  23  is heated to its melting point. The molten solder paste  23  flows from the accommodating hole  224  into the receiving hole  223  of each fin  22  to fill up the clearance between the flat heat pipe  21  and the combining sidewall  24  of each fin  22  via capillary force and gravity. Referring to  FIG. 5 , after the molten solder paste  23  is cooled, a solder layer  231  is formed between the flat heat pipe  21  and the combining sidewall  24  of each fin  22 , securely combining the flat heat pipe  21  and the fins  22  together. 
     In this heat dissipation apparatus  200 , the accommodating hole  224  is arranged at a corner of the receiving hole  223 . The effective contacting surface of the flat heat pipe  21  (i.e., the top planar face  213  and the bottom planar face  214 ) is fully combined to the combining sidewalls  24  of the fins  22 . Comparing with the conventional heat dissipation apparatus  100  shown in  FIGS. 1 and 2 , the heat transfer efficiency between the flat heat pipe  21  and the fins  22  is greatly increased. In addition, due to the accommodating hole  224  being arranged at a corner of the receiving hole  223 , the molten solder paste  23  firstly flows downwardly towards the bottom planar plate  242  quickly via gravity, and then flows horizontally along the bottom planar plate  242  via capillary force. The molten solder paste  23  can fully fill up a clearance between the bottom planar face  214  of the flat heat pipe  21  and the bottom planar plate  242  of the combining sidewall  24 . Thus, an insufficient soldering will not occur between the bottom planar face  214  of the flat heat pipe  21  and the bottom planar plate  242  of the combining sidewall  24 . The heat transfer efficiency between the flat heat pipe  21  and the fins  22  is further increased. 
     Referring to  FIG. 6 , a heat dissipation apparatus  200   a  in accordance with a second embodiment is shown. The heat dissipation apparatus  200   a  includes the flat heat pipe  21  and a plurality of fins  22   a . Each fin  22   a  defines an elongated receiving hole  223   a  therein for receiving the flat heat pipe  21  and a small-sized accommodating hole  224   a  therein for accommodating solder paste. Except the following difference, the heat dissipation apparatus  200   a  of the present embodiment is essentially the same as the heat dissipation apparatus  200  illustrated in  FIGS. 3-5 . In the present embodiment, the accommodating hole  224   a  extends along a length direction of the receiving hole  223   a  and is located a left side of the receiving hole  233   a.    
     Referring to  FIGS. 7 and 8 , a heat dissipation apparatus  200   b  in accordance with a third embodiment is shown. The heat dissipation apparatus  200   b  includes the flat heat pipe  21  and a plurality of fins  22   b . Each fin  22   b  defines an elongated receiving hole  223   b  therein for receiving the flat heat pipe  21 . A combining sidewall  24   b  extends vertically from an edge of the receiving hole  223   b  of the fin  22   b . The combining sidewall  24   b  includes an elongated top planar plate  241   b , an elongated bottom planar plate  242   b  opposite to the top planar plate  241   b , and two curved short plates  243   b ,  244   b  (i.e., left short plate  243   b  and right short plate  244   b ) at left and right sides of the receiving hole  233   b . Except the following differences, the heat dissipation apparatus  200   b  of the present embodiment is essentially the same as the heat dissipation apparatus  200  illustrated in  FIGS. 3-5 . In the present embodiment, the fin  22   b  defines two accommodating holes  224   b  therein for accommodating two solder pastes  23   b . The accommodating holes  224   b  are located at two corners of the receiving hole  223   b  (i.e., top left corner and top right corner of the receiving hole  223   b ) and communicate with the receiving hole  233   b . In other words, the two accommodating holes  224   b  are respectively located at two ends of the top planar plate  241   b  and are respectively located at top ends of the two short plates  243   b ,  244   b . One of the two accommodating holes  224   b  is located at a junction of the top planar plate  241   b  and the left short plate  243   b , while the other of the two accommodating holes  224   b  is located at a junction of the top planar plate  241   b  and the right short plate  244   b . The two accommodating holes  224   b  extend along a width direction of the receiving hole  223   b  and are located above the receiving hole  233   b . A combining plate  245   b  extends vertically from an edge of each accommodating hole  224   b  of the fin  22   b . Two ends of each combining plate  245   b  connect with a top end a corresponding short plate  243   b  ( 244   b ) and one end of the top planar plate  241   b  of the combining sidewall  24   b . Thus, the combining plate  245   b  and the combining sidewall  24   b  cooperatively form a closed wall. 
     Referring to  FIG. 7 , the flat heat pipe  21  is inserted in the receiving holes  233   b  of the fins  22   b . A clearance exists between the outer surface of the flat heat pipe  21  and the combining sidewall  24   b  of each fin  22   b  before the flat heat pipe  21  and the fins  22   b  are soldered together. Two solder pastes  23   b  are accommodated in the two accommodating holes  224   b  of each fin  22   b , respectively. When soldering, the solder pastes  23   b  are heated to their melting point. The molten solder pastes  23   b  flow from the two accommodating holes  224   b  into the receiving hole  223   b  of each fin  22   b  to fill up the clearance between the flat heat pipe  21  and the combining sidewall  24   b  of each fin  22   b  via capillary force and gravity. Referring to  FIG. 8 , after the solder pastes  23   b  are cooled, a solder layer  231   b  is formed between the flat heat pipe  21  and the combining sidewall  24   b  of each fin  22   b , securely combining the flat heat pipe  21  and the fins  22   b  together. 
     In the heat dissipation apparatus  200   b  of this embodiment, the two accommodating holes  224   b  are arranged at two corners of the receiving hole  223   b  (i.e., junctions of the top planar plate  241   b  and the two short plates  243   b ,  244   b ). The effective contacting surface of the flat heat pipe  21  (i.e., the top planar face  213  and the bottom planar face  214 ) is fully combined to the combining sidewalls  24   b  of the fins  22   b . Comparing with the conventional heat dissipation apparatus  100  shown in  FIGS. 1 and 2 , the heat transfer efficiency between the flat heat pipe  21  and the fins  22   b  is greatly increased. In addition, due to the two accommodating holes  224   b  being arranged at two corners of the receiving hole  223   b , a flow distance of the molten solder paste  23   b  from each accommodating hole  224   b  to a center portion of the bottom planar plate  242   b  of the combining sidewall  24   b  is decreased. The molten solder paste  23   b  can fully fill up a clearance between the bottom planar face  214  of the flat heat pipe  21  and the bottom planar plate  242   b  of the combining sidewall  24   b . Thus, an insufficient soldering will not occur between the bottom planar face  214  of the flat heat pipe  21  and the bottom planar plate  242   b  of the combining sidewall  24   b . The heat transfer efficiency between the flat heat pipe  21  and the fins  22   b  is further increased. 
     Referring to  FIG. 9 , a heat dissipation apparatus  200   c  in accordance with a fourth embodiment is shown. The heat dissipation apparatus  200   c  includes the flat heat pipe  21  and a plurality of fins  22   c . Each fin  22   c  defines an elongated receiving hole  223   c  therein for receiving the flat heat pipe  21  and two small-sized accommodating holes  224   c  therein for accommodating solder pastes. Except the following difference, the heat dissipation apparatus  200   c  of the present embodiment is essentially the same as the heat dissipation apparatus  200   b  illustrated in  FIGS. 7-8 . In the present embodiment, the two accommodating holes  224   c  extend along a length direction of the receiving hole  223   c  and are located left and right sides of the receiving hole  233   c.    
     Referring to  FIG. 10 , a heat dissipation apparatus  200   d  in accordance with a fifth embodiment is shown. The heat dissipation apparatus  200   d  includes the flat heat pipe  21  and a plurality of fins  22   d . Each fin  22   d  defines an elongated receiving hole  223   d  therein for receiving the flat heat pipe  21  and a small-sized accommodating hole  224   d  therein for accommodating solder paste. A combining sidewall  24   d  extends vertically from an edge of the receiving hole  223   d  of the fin  22   d . The combining sidewall  24   d  includes an elongated top planar plate  241   d , an elongated bottom planar plate  242   d  opposite to the top planar plate  241   d , and a curved short plate  243   d  at a left side of the receiving hole  233   d . The accommodating hole  224   d  is located at a junction of the top planar plate  241   d  and the left short plate  243   d . Except the following difference, the heat dissipation apparatus  200   d  of the present embodiment is essentially the same as the heat dissipation apparatus  200  illustrated in  FIGS. 3-5 . In the present embodiment, a right side of the receiving hole  223   d  (i.e., a side opposite to the left short plate  243   d ) is open. 
     It is to be understood, however, that even though numerous characteristics and advantages of the disclosure have been set forth in the foregoing description, together with details of the structure and function of the disclosure, 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.