Patent Publication Number: US-2009236077-A1

Title: Heat dissipation device

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a heat dissipation device, and more particularly to a heat dissipation device for dissipating heat generated by an electronic component. 
     2. Description of related art 
     A computer central processing unit (CPU) is the core controller of electrical signals in the contemporary personal computers. Continued development of the CPUs has enabled them to perform more and more functions. Heat generated by the CPUs has thus increased enormously. Such heat can adversely affect the operational stability of the computers. Measures must be taken to efficiently remove the heat from the CPU. Typically, a dissipation device having great heat conductivity is mounted on the CPU to remove the heat therefrom. 
     The conventional heat dissipation device commonly comprises a base thermally contacting with the CPU, a plurality of fins extending upwardly from a top of the base, and a fan mounted on a top portion of the heat sink. The fins are perpendicular to the base and parallel to each other with a predetermined distance; thus, a plurality of linear airflow passages is defined between the fins. When the heat dissipation device works, airflow generated by the fan blows spirally and downwardly into the airflow passages of the heat sink. The fins are so oriented that they have varied confronting angles with the airflow. Accordingly, a part of the fins cannot have a thorough contact with airflow, whereby heat in the part of the fins cannot be effectively taken away by the airflow flowing through the heat sink. Thus, heat dissipation efficiency of the heat dissipation device is not high and still needs to improve. 
     Thus, it is desired to devise a heat dissipating device which having a good heat dissipation efficiency. 
     SUMMARY OF THE INVENTION 
     A heat dissipation device for dissipating heat generated by an electronic component includes a base, a fin group and a heat pipe connecting the base with the fin group. The base thermally contacts with the electronic component. The fin group includes a plurality of fins located at a top of the base. The heat pipe includes an evaporating portion received in the base, a condensing portion extending spirally and upwardly from an end of the evaporating portion. The condensing portion of the heat pipe extends through the fin group. The fins of the fin group are arranged to have an arch-shaped profile. A fan is mounted over the fin group. 
     Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the present embodiments 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 embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an assembly view of a heat dissipation device in accordance with a preferred embodiment of the present invention; 
         FIG. 2  is an exploded view of the heat dissipation device of  FIG. 1 ; 
         FIG. 3  is an exploded view of heat sinks of the heat dissipation device of  FIG. 2 ; and 
         FIG. 4  is a front elevational view of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1-2 , they illustrate a heat dissipation device for dissipating heat generated by an electronic component (not shown) mounted on a printed circuit board (not shown). The heat dissipation device comprises a heat sink assembly  10  thermally contacting with the electronic component, a fan holder  20  securing the heat sink assembly  10  on the printed circuit board, and a fan  30  mounted on a top of the heat sink assembly  10  and supported by the fan holder  20 . 
     The heat sink assembly  10  comprises a base  12  contacting with the electronic component and a pair of heat sinks  19  located at a top of the base  12 . Each heat sink  19  comprises a fin group  14 , and a first heat pipe  16  and a second heat pipe  18  connecting the fin group  14  with the base  12 . 
     The base  12  is located at a bottom of the fin groups  14  and spaced from the fin groups  14 . The base  12  is substantially rectangular and made of metal with high degree of heat conductivity such as copper or aluminum. Four spaced grooves  124  are parallel to each other and defined in a bottom portion of the base  12  for receiving the first and second heat pipes  16 ,  18 . A plurality of ribs (not labeled) extends from a top of the base  12 . Two locking portions (not labeled) are formed at opposite sides of the base  12  for engaging with a pair of locking members  13 . Each locking member  13  comprises a mounting plate (not shown) located below the locking portions of the base  12  and a pair of legs  132  extending outwardly from opposite ends of the mounting plate. Screws (not shown) extend through the mounting plates and engage with the locking portions of the base  12  to mount the locking members  13  on the base  12 . 
     Referring to  FIGS. 3-4  also, each first heat pipe  16  comprises a flattened and horizontal evaporating portion  160  received in a corresponding groove  124  of the base  12 , an arc-shaped condensing portion  166  received in the fin group  14 , and a connecting portion  164  interconnecting the evaporating portion  160  and the condensing portion  166 . The connecting portion  164  and the condensing portion  166  extend spirally and upwardly from an end of the evaporating portion  160  along an anti-clockwise direction. Each second heat pipe  18  comprises a flattened evaporating portion  180  received in a corresponding groove  124  of the base  12 , an arc-shaped condensing portion  186  received in the fin group  14 , and a connecting portion  184  connecting the evaporating portion  180  with the condensing portion  186 . More specifically, the arc-shaped condensing portion  186  has a semicircular configuration. As shown in  FIG. 4 , the connecting portions  164 ,  184  of the heat pipes  16 ,  18  in connection with one of the fins groups  14  extend from a front side of the base  12 , while the connecting portions  164 ,  184  of the heat pipes  16 ,  18  in connection with the other of the fin groups  14  extend from a rear side of the base  12 . The two evaporating portions  160 ,  180  of the first and second heat pipes  16 ,  18  are adjoined. The connecting portion  184  and the condensing portion  186  extend spirally and upwardly from an end of the evaporating portion  180  along an anti-clockwise direction. The condensing portion  186  is located at an outer side of the fin group  14  and the condensing portion  166  is located at an inner side of the fin group  14 . The condensing portion  186  and the condensing portion  166  in the same fin group  14  are parallel to each other. 
     Each fin group  14  comprises a plurality of vertical fins  140 . The fins  140  are spaced from each other with a predetermined distance; thus a plurality of airflow passages (not labeled) is defined between every neighboring two of the fins  140 . Each fin  140  is substantially rectangular and perforated with two through holes (not labeled) at a centre portion thereof. An outward corner of each fin  140  is bent to form a bent plate  148  for guiding airflow generated by the fan into the airflow passages of the fin group  14 . A cutout  144  is defined in a lower portion of each fin  140  to receive the connecting portions  164 ,  184  of the first and second heat pipes  16 ,  18  of the other heat sink  19 . Annular flanges  146  are formed during punching the through holes of the fins  14 . The flanges  146  in each fin group  14  are soldered together to form a spiral-shaped channel (not labeled) along an anti-clockwise direction; thus, when the fins  140  of each fin group  14  are assembled together, two spiral channels (not labeled) are defined in the each fin group  14 . The condensing portions  166 ,  186  of the first and second heat pipes  16 ,  18  are soldered in the channels, so that the first and second heat pipes  16 ,  18  and the fin group  14  are assembled together. The fins  140  of the fin group  14  are perpendicular to the condensing portions  160 ,  180  of the first and second heat pipes  16 ,  18 . 
     The pair of heat sinks  19  are located at opposite sides of the base  12 . The evaporating portions  160 ,  180  of the first and second heat pipes  16 ,  18  are received in the grooves  124  of the base  12  and coplanar with a bottom surface of the base  12  to contact with the electronic component. The connecting portions  164 ,  184  of the first and second heat pipes  16 ,  18  of one of the heat sinks  19  are opposite those of the other of the heat sinks  19 . The connecting portions  164 ,  184  of the first and second heat pipes  16 ,  18  of the two heat sinks  19  are received in the cutouts  144  of the fin groups  14 . The fin groups  14  each are formed with a substantially arch-shaped configuration. The fin groups  14  together form an annular configuration. 
     The fan holder  20  comprise four sleeves  22  each with a bottom portion abutting a corresponding leg  132  of the locking members  13 , a pair of arc-shaped supporting plates  24  mounted on tops of the sleeves  22  and four elongated screws  26 . The screws  26  extend through the supporting plates  24 , the sleeves  22  and the legs  132  to threadedly engage with a fastening plate (not shown) under the printed circuit board thereby to mount the heat sink assembly  10  and the fan holder  20  on the printed circuit board. Opposite ends of each supporting plates  24  define mounting holes  240  respectively, whereby screws  50  can extend through the fan  30  to threadedly engage in the mounting holes  240  to thereby mount the fan  30  on the supporting plates  24 . 
     The fan  30  has a circular configuration and comprises a cage (not labeled) and an impeller assembly (not labeled) received in the cage. Four mounting portions  35  extend outwardly from the cage of the fan  30 , located corresponding to the opposite ends of the supporting plates  24 . The screws  50  extend through the mounting portions  35  and engage into the mounting holes  240  of the supporting plates  24  to mount the fan  30  on the supporting plates  24 . 
     In use, heat generated by the electronic component is absorbed by the base  12 , then transferred to the fin group  14  via the first and second heat pipes  16 ,  18 , and finally dispersed into ambient cool air. Airflow generated by the fan  30  spirally blows into airflow passages of the fin groups  14  along the anti-clockwise direction to dissipate heat generated by the electronic component. Due to the airflow passages of the fin groups  14  extending upwardly along the anti-clockwise direction and the airflow spirally blowing into the airflow passages along the anti-clockwise direction, the airflow generated by the fan  30  can easily blow into the airflow passages to have a thorough contact with all of the fins  140 . Thus, heat dissipation efficiency of the heat dissipation device is improved. Furthermore, the bent plates  148  of the fin groups  14  extend outwardly from the fins  140 ; thus, the airflow generated by the fan  30  can more easily blow into the airflow passages by a guidance of the bent plates  148  to take away heat in the fins  140 . 
     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 invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.