Abstract:
A heat dissipating device incorporating heat pipes is disclosed. The heat dissipating device includes a base, a plurality of heat-dissipating fins and at least one heat pipe. The heat pipe includes an evaporating portion attached to the base, a middle-portion and a condensing portion extending through the fins. Bottoms of the evaporating portion of the heat pipe and the base are coplanar, and the condensing portion extends opposite to the evaporating portion.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates generally to heat dissipating devices for removing heat from heat-generating devices, and more particularly to a heat dissipating device incorporating with heat pipes for promoting heat dissipation effect thereof  
       BACKGROUND  
       [0002]     Computer electronic devices such as central processing units (CPUs) generate lots of heat during normal operation. If not properly removed, such heat can adversely affect the operational stability of computers. Solutions must be taken to efficiently remove the heat from the CPUs. Typically, a heat sink is mounted on a CPU to remove heat thereon, and a fan is often attached to the heat sink for improving heat-dissipating efficiency of the heat sink. The heat sink commonly comprises a base and a plurality of heat-dissipating fins arranged on the base.  
         [0003]     Nowadays, CPUs and other related computer electronic devices are becoming functionally more powerful and more heat is produced consequently, resulting in an increasing need for removing the heat away more rapidly. Conventional heat sinks made of metal materials, even a fan is used, gradually cannot satisfy the need of heat dissipation. Accordingly, another kind of heat dissipating device incorporating with heat pipes has been designed to meet the current heat dissipation need, as the heat pipe possesses an extraordinary heat transfer capacity and can quickly transfer heat from one point to another thereof Commonly, a heat pipe consists of a sealed aluminum or copper container with the internal walls lined with a capillary wick structure that is filled with a working fluid. As the heat pipe absorbs heat at one end thereof fluid is vaporized, and a pressure gradient is formed in the pipe. This pressure gradient forces the vapor to flow along the pipe from the one end to the other end where the vapor condenses and gives out its latent heat of vaporization. The working fluid is then returned back to the one end of the pipe via the capillary forces developed in the wick structure. When used, an end of the heat pipe is attached to the base of a heat sink, and the other end of the heat pipe is attached to a plurality of heat-dissipating fins of the heat sink. Thus the heat generated by electronic devices is conducted to the base and then rapidly transferred to the heat-dissipating fins via the heat pipe for further dissipating to ambient air.  
         [0004]     However, the above-mentioned heat dissipating device incorporating with heat pipes has a disadvantage that it exists a big thermal resistance between the heat pipe and an electronic device, which decreases the heat dissipation efficiency of the heat dissipating device.  
         [0005]     Therefore, it is desired to design a novel heat dissipating device to overcome the aforementioned problems and increase the heat dissipation effect thereof  
       SUMMARY  
       [0006]     Accordingly, an object of the present invention is to provide a heat dissipating device incorporating with heat pipes which decreases heat resistance between the heat pipe and an electronic device to increase the heat dissipation efficiency thereof  
         [0007]     In order to achieve the object above, a heat dissipating device for removing heat from heat-generating component in accordance with the present invention comprises a base, a plurality of heat-dissipating fins and at least one heat pipe. The heat pipe comprises an evaporating portion attached to the base, a middle-portion and a condensing portion extending through the fins. Bottoms of the evaporating portion of the heat pipe and the base are coplanar, and the condensing portion extends opposite to the evaporating portion.  
         [0008]     Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is an exploded, isometric view of a heat dissipating device in accordance with one preferred embodiment of the present invention;  
         [0010]      FIG. 2  is an assembled view of the heat dissipating device of  FIG. 1 ; and  
         [0011]      FIG. 3  is an exploded, isometric view of a heat dissipating device in according with an alternative embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0012]     Reference will now be made to the drawing figures to describe the present invention in detail.  
         [0013]      FIG. 1-2  show a preferred embodiment of a heat dissipating device in accordance with present invention. The heat dissipating device comprises two heat sinks  1 ,  2 , a heat receiver such as a base  4 , three heat pipes  5  thermally connecting the base  4  with the heat sinks  1 ,  2 .  
         [0014]     The base  4  has a top surface  43  and a bottom surface  42  opposite to the top surface  43 . The bottom surface  42  of the base  4  is planar for contacting a heat-generating component (not shown). The base  4  defines three grooves  40  in the bottom surface  42  thereof One end of the base  4  defines three gaps  41  in connection with the grooves  40 . The gaps  41  are extended through the top and bottom surfaces  42 , 43  of the base.  
         [0015]     Each heat pipe  5  is tube-shaped and has an evaporating portion  51 , a middle-portion  53  and a condensing portion  52  extending opposite to the evaporating portion  51 . The middle-portion  53  is a curved-portion. The evaporating portion  51  of the heat pipe  5  defines a plane surface  510  directly contacting the heat-generating component. The plane surface  510  is coplanar with the bottom surface  42  of the base  4 . The roughness of the plane surface  510  and the bottom surface  42  is better less than  0 . 08 mm. Then, the plane surface  510  can intimately contact the heat-generating component. The plane surface  510  is made by means of precision machining, such as milling. The condensing portion  52  is extended parallel to the plane surface  510 , which can save room along a direction perpendicular to the plane surface  510 .  
         [0016]     The heat sinks  1 ,  2  each comprise a plurality of parallel fins. The heat sink  1  comprises a face  10  facing the top surface  43  of the base  4 . Three U-shaped cavities  11  are defined in an end of the heat sink  1 . The middle-portions  53  of the heat pipe  5  are engaging with the heat sink  1  in the cavities  11 . The heat sink  2  defines holes  20  therein.  
         [0017]     In assembly, The heat sink  1  is attached to the top surface  43  of the base  4 . Said end of the heat sink  1  where the cavities  11  are defined is aligned with said end of the base  4  where the gaps  41  are defined. The evaporating portions  51  of the heat pipes  5  are thermally engaged in the slots  40  of the base  4 , with part thereof exposed beyond the base  4 . The exposed part of the evaporating portions  51  and the bottom surface  42  of the base  4  are simultaneity milled to form the plane surfaces  510  which is coplanar with the bottom surface  42  of the base  4 . The heat sink  1  is thermally mounted on the top surface  43  of the base  4 . The cavities  11  of the heat sink  1  are engaged with the middle-portions  53  extending through the gaps  41  of the base  4 . The condensing portions  52  are thermally inserted in the holes  20  of the heat sink  2 . The evaporating portions  51 , the middle-portions  53  and the condensing portions  52  might be engaged in the slots  40 , cavities  11  and the holes  20  respectively, by means of soldering, bonding, or be interferentially received respectively in the slots  40 , cavities  11  and the holes  20 .  
         [0018]     Referring to  FIGS. 1-2 , when used, the base  4  might be in thermally conductive relation to the heat-generating component. The heat pipes  5  directly absorb heat from the heat-generating component via the evaporating portion  51 , and transfer the heat to the heat sink  2  via the condensing portions  52  and to the heat sink  1  via the base  4 . The base  4  also absorbs heat from the heat-generating component and transfers the heat to the heat sink  1 . The heat on the heat sink  1 ,  2  is further radiated to ambient air via the fins thereon.  
         [0019]     As illustrated in  FIG. 3 , two heat sinks  2 ′ are used. Each heat sink  2 ′ is almost the same as the heat sinks  2  of  FIG. 1 . Each heat pipe  45  has an evaporating portion  451  attached to a corresponding groove defined in a base  4 ′, two condensing portions  452  and two middle-portions  453  thermally connecting the evaporating portion  451  to the condensing portions  452 . The evaporating portion  451  has a plane surface  450  directly contacting a heat-generating component. Two condensing portions  452  respectively thermally contact the heat sink  2 ′. A top surface of the base  4 ′ thermally contacts a heat sink  1 ′.  
         [0020]     The heat dissipating devices of the present invention have achieved much better heat dissipation efficiency since the surfaces  510 ,  450  directly contact the heat-generating component. Heat resistance between the heat pipes and the heat-generating component can be decreased Selectively, a fan unit can be attached to the heat dissipating device for providing forced airflow to further enhance the heat dissipation efficiency of the heat dissipating device.  
         [0021]     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 fill extent indicated by the broad general meaning of the terms in which the appended claims are expressed.