Abstract:
Disclosed is a heat pipe with expanded heat receiving section, and a heat dissipation module using the heat pipe. The heat-receiving section is in physical engagement with a heat conduction box of the heat dissipation module. A fan is arranged between the heat conduction box and a heat dissipation fin module. The heat conduction box and the heat dissipation fin module form, at locations corresponding to the heat-receiving section and the heat-dissipating section, a heat-receiving section receiving slot and a heat-dissipating section receiving slot, respectively, to receive and retain the heat-receiving section and the heat-dissipating section therein.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a heat pipe, and in particular to a heat pipe having a heat receiving section comprised of expanded tube to provide an enlarged area for thermal transfer, and a heat dissipation module using the heat-receiving-section-expanded heat pipe.  
       BACKGROUND OF THE INVENTION  
       [0002]     Integrated circuit devices have been widely used in a variety of industrial facility, measuring equipments, and computers. The integrated circuit devices must be maintained within specific working temperatures in order to function normally. Thus, the integrated circuit devices are often coupled to heat dissipation devices or systems to effectively dissipate heat to the surroundings for maintaining the specific working temperatures. This is particularly true for a central processing unit, which serves as an operation center of a computer system and thus the requirement for heat dissipation is even more severe.  
         [0003]     With the increased speed of the central processing unit, and other integrated circuit devices, the performance of the heat dissipation or system has to be improved accordingly. The conventionally used heat dissipation board and heat dissipation fin are no longer capable to effectively cool the integrated circuit down to the specific working temperature. Thus, heat dissipation fans and heat pipes are additionally include in the heat dissipation system to enhance the heat removal rate and realizes effective heat dissipation. Further, since a notebook computer or a tablet computer is often of a smaller size and lighter weight, as compared to the regular desktop computer, the heat dissipation for the central processing unit of the notebook computer or tablet computer is subject to very severe requirement in performance. However, due to the smaller size, internal space of the notebook computer and the tablet computer is very limited, which imposes constraint to the design and installation of heat dissipation system in the notebook computer or the tablet computer.  
         [0004]      FIG. 1  of the attached drawings shows a conventional heat-pipe-included heat dissipation module for a notebook computer. As shown in  FIG. 1 , the conventional heat dissipation module, which is generally designated with reference numeral  1 , is positioned on and maintained in physical contact with a top face of a heat-generating element  2 , such as a central processing unit. The heat dissipation module  1  comprises a heat conduction box  11 , a fan  12 , a heat dissipation fin module  13 , a heat dissipation channel  14 , and a heat pipe  15 .  
         [0005]     The heat dissipation module  1  is constructed so as to fix the fan  12  between the heat conduction box  11  and the heat dissipation fin module  13  and the heat dissipation fin module  13  is received and retained in the heat dissipation channel  14  that extends from the heat conduction box  11  and defines a plurality of air passages therein through which heat dissipation airflows caused by the fan  12  pass. The heat generated by the heat-generating element  2  can be effectively dissipated by the airflows generated by the fan  12 , together with heat exchange effected by the heat dissipation fin module  13 .  
         [0006]     Also referring to  FIG. 2  of the attached drawings, the heat pipe  15  of the heat dissipation module  1  is comprised of a heat-receiving section  151 , a heat-transfer section  152 , and a heat-dissipating section  153 . The heat-receiving section  151  is connected to an end of the heat conduction box  11  of the heat dissipation module  1  that is in physical contact with the heat-generating element  2  and the heat dissipating section  153  is coupled to the heat dissipation fin module  13 , whereby heat generated by the heat-generating element  2  is transferred through the heat-transfer section  152  and the heat-dissipating section  153  to the heat dissipation fins that comprise the heat dissipation fin module  13 , which, together with the operation of the fan  12  that induces airflows for heat dissipation, may dissipate heat that is transferred to the heat dissipation fins to the surroundings.  
         [0007]     A heat-receiving section receiving slot  16  and a heat-dissipating section receiving slot  17  are respectively formed in suitable locations on the heat conduction box  11  and the heat dissipation fin module  13 . The heat-receiving section  151  and the heat-dissipating section  153  are respectively received and retained in the heat-receiving section receiving slot  16  and the heat-dissipating section receiving slot  17 . This improves the heat transfer rate between the heat pipe  15  and the heat conduction box  11 .  
         [0008]     The conventional heat dissipation modules, although subject to severe constraint of limited inside space, can realize effect heat dissipation for notebook computers. In practical applications, although the heat pipe comprised of the conventional heat dissipation module plays a good role in heat transfer and the heat-receiving section of the heat pipe that is connected to the end of the heat dissipation module that is in physical contact with the heat-generating element does transfer heat from the connection therebetween, through the heat pipe, to the fin section, a portion of the heat is incorrectly transferred through the heat conduction box and inducing an undesired thermal build-up therein.  
         [0009]     Adding one or more extra heat pipes or using a heat pipe of increased cross-section area has been proposed to overcome the poor performance of heat transfer in the conventional designs. These solutions, however, require additional occupation of the very limited space inside the notebook computers and are not, to some extents, economic.  
         [0010]     Thus, the key challenge here is to improve the structure of the heat pipe itself, which allows for efficient transfer of heat from the heat-generating element to the heat dissipation fin module to effect excellent heat dissipation performance.  
       SUMMARY OF THE INVENTION  
       [0011]     An objective of the present invention is to provide a heat pipe having an expanded heat-receiving section, which effectively enhances the heat dissipation performance of a heat dissipation module that incorporates the heat pipe without addition of extra heat pipe(s).  
         [0012]     Another objective of the present invention is to provide an improvement on the structure of heat pipe, which allows for further increasing contact area between the heat pipe and a heat source at positions of intense eat distribution identified by experiment and analysis of thermal and temperature distribution to further enhance performance of heat dissipation.  
         [0013]     A further objective of the present invention is to provide a heat dissipation comprised of a heat pipe having an expanded heat-receiving section, whereby the performance of heat dissipation of the heat dissipation module is enhanced by the expanded heat-receiving section of the heat pipe in physical engagement with a heat conduction box of the heat dissipation module.  
         [0014]     To realize the above objectives, in accordance with an embodiment of the present invention, a heat pipe comprises a heat-receiving section comprising an expanded tube of different geometry by which a contact area for heat transfer is increased to effectively enhance the performance of heat dissipation. In accordance with the present invention, the heat-receiving section of the heat pipe is extended to integrally form an expanded heat-receiving segment, which extends from an end of the heat-receiving section of the heat pipe and is in physical engagement with a heat conduction box of a heat dissipation module. A fan is further arranged between the heat conduction box of the heat dissipation module and a heat dissipation fin module.  
         [0015]     In a preferred embodiment of the present invention, the heat conduction box and the heat dissipation fin module form, at positions corresponding to the heat-receiving section and a heat-dissipating section of the heat pipe, a heat-receiving section receiving slot and a heat-dissipating section receiving slot, respectively, for receiving and retaining therein the heat-receiving section and the heat-dissipating section of the heat pipe.  
         [0016]     Compared to the conventional devices, the present invention enhances the heat dissipation performance of a heat dissipation module without adding extra heat pipe(s) and allows for further improvement of the heat dissipation performance by means of comparison and verification by experiments and analyses. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     The present invention will be apparent to those skilled in the art by reading the following description of preferred embodiments thereof, with reference to the attached drawings, in which:  
         [0018]      FIG. 1  is a perspective view showing a conventional heat dissipation module for a notebook computer;  
         [0019]      FIG. 2  is an exploded view of the conventional heat dissipation module with a heat pipe detached from the module;  
         [0020]      FIG. 3  is a perspective view of a heat dissipation module constructed in accordance with a first embodiment of the present invention;  
         [0021]      FIG. 4  is an exploded view of the heat dissipation module of the present invention with a heat pipe detached therefrom;  
         [0022]      FIG. 5  is a plan view of the heat pipe in accordance with the present invention;  
         [0023]      FIG. 6  is a cross-sectional view taken along line  6 - 6  of  FIG. 5 ;  
         [0024]      FIG. 7  is a cross-sectional view taken along line  7 - 7  of  FIG. 5 ;  
         [0025]      FIG. 8  is a cross-sectional view taken along line  8 - 8  of  FIG. 5 ;  
         [0026]      FIG. 9  is an exploded view of a heat dissipation module constructed in accordance with a second embodiment of the present invention with a heat pipe detached from the module;  
         [0027]      FIG. 10  is a perspective view of a heat dissipation module constructed in accordance with a third embodiment of the present invention;  
         [0028]      FIG. 11  is an exploded view of the heat dissipation module of the third embodiment of the present invention with a heat pipe detached therefrom; and  
         [0029]      FIG. 12  is an exploded view of a heat dissipation module constructed in accordance with a fourth embodiment of the present invention with a heat pipe detached from the module. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0030]     With reference to the drawings and in particular to  FIGS. 3 and 4 , which show a perspective view and an exploded view of a heat dissipation module constructed in accordance with a first embodiment of the present invention, generally designated with reference numeral  1 , the heat dissipation module  1  of the first embodiment of the present invention comprises a uniformly-expanded heat pipe  3 , which comprises a heat-receiving section  31 , a heat-transfer section  32 , and a heat-dissipating section  33 .  
         [0031]     The heat-receiving section  31  is coupled to an end of a heat conduction box  11  of the heat dissipation module  1  that physically contacts a heat source formed by a heat-generating element  2  and the heat-dissipating section  33  is coupled to a heat dissipation fin section  13  of the heat dissipation module  1  whereby heat generated by the heat-generating element  2  is transferred through the heat-transfer section  32  and the heat-dissipating section  33  to heat dissipation fins that constitute the heat dissipation fin module  13 , which, together with heat dissipation airflows induced by a fan  12 , effectively dissipates heat transferred to the heat dissipation fins to the surroundings.  
         [0032]     A major difference between the instant embodiment and the conventional heat pipe is that the heat-receiving section  31  of the uniformly-expanded heat pipe  3  of the present invention comprises a primitive segment  311  and an expanded segment  312 . An end of the primitive segment  311  is connected to the heat-transfer section  32 . The expanded segment  312  has a gradually-expanded portion  312   a  and a uniformly-expanded portion  312   b.    
         [0033]     The gradually-expanded portion  312   a  has an end connected to an opposite end of the primitive segment  311  and the uniformly-expanded portion  312   b  extends from an opposite end of the gradually-expanded portion  312   a.  In the instant embodiment, the uniformly-expanded portion  312   b  has a cross-sectional dimension greater than a cross-sectional dimension of the primitive segment  311 , while cross-sectional dimension of the gradually-expanded portion  312   a  is gradually increased from the connection thereof with the primitive segment  311  toward the connection thereof with the uniformly-expanded portion  312   b.    
         [0034]     The heat conduction box  11  and the heat dissipation fin module  13  form, at suitable locations, a heat-receiving section receiving slot  16  and a heat-dissipating section receiving slot  17 . The heat-receiving section  31  and the heat-dissipating section  33  of the uniformly-expanded heat pipe  3  are received and retained in the heat-receiving section receiving slot  16  and the heat-dissipating section receiving slot  17  of the heat dissipation module  1 , respectively.  
         [0035]     In practice, the primitive segment  311 , the gradually-expanded portion  312   a,  and the uniformly-expanded portion  312   b  are integrally formed together.  
         [0036]     Also referring to  FIGS. 5-8 , which show a plan view of the heat pipe  3 , and cross-sectional views taken along lines  6 - 6 ,  7 - 7 , and  8 - 8  of  FIG. 5 , respectively, the dimensions of the heat-receiving section  31 , the expanded segment  312 , the heat-transfer section  32 , and the heat-dissipating section  33  will be discussed.  
         [0037]     By designating a first dimension (height) and a second dimension (width) of the expanded segment  312  of the heat-receiving section  31  with h 1  and w 1  respectively; a first dimension (height) and a second dimension (width) of the heat-transfer section  32  with h 2  and w 2  respectively; and a first dimension (height) and a second dimension (width) of the heat-dissipating section  33  with h 3  and w 3  respectively, the following conditions are satisfied:  
         [0038]     (a) The first dimension h 1  of the expanded segment  312  is greater than the first dimension h 2  of the heat-transfer section  32 ;  
         [0039]     (b) The first dimension h 1  of the expanded segment  312  is greater than the first dimension h 3  of the heat-dissipating section  33 ;  
         [0040]     (c) The second dimension w 1  of the expanded segment  312  is greater than the second dimension w 2  of the heat-transfer section  32 ; and  
         [0041]     (d) The second dimension w 1  of the expanded segment  312  is greater than the second dimension w 3  of the heat-dissipating section  33 .  
         [0042]     With reference to  FIG. 9 , which shows an exploded view of a heat dissipation module, also designated with reference numeral  1  for simplicity, constructed in accordance with a second embodiment of the present invention, the heat dissipation module  1  of the second embodiment comprises a uniformly-expanded heat pipe, designated with reference numeral  3 ′ for distinction, which is different from the uniformly-expanded heat pipe  3  of the first embodiment in that the heat-receiving section  31  of the uniformly-expanded heat pipe  3  of the first embodiment is replaced by a heat-receiving section  31 ′ that, instead of being comprised of a primitive segment and an expanded segment, is totally comprised of an expanded segment, which comprises a gradually-expanded portion  311 ′ and a uniformly-expanded portion  312 ′. The gradually-expanded portion  311 ′ is connected to the heat-transfer section  32 , and the uniformly-expanded portion  312 ′ is connected to the gradually-expanded portion  311 ′ and is constructed to have a cross-sectional dimension greater than that of the heat-transfer section  32 . The gradually-expanded portion  311 ′ has a cross-sectional dimension that is increased from the connection thereof with the heat-transfer section  32  toward the connection thereof with the uniformly-expanded portion  312 ′.  
         [0043]     With reference to  FIGS. 10 and 11 , which show a perspective view and an exploded view of a heat dissipation module, also designated with reference numeral  1  for simplicity, constructed in accordance with a third embodiment of the present invention, the heat dissipation module  1  of the third embodiment comprises a gradually-expanded heat pipe  4  comprising a heat-receiving section  41 , a heat-transfer section  42 , and a heat-dissipating section  43 .  
         [0044]     The heat-receiving section  41  is coupled to an end of a heat conduction box  11  of the heat dissipation module  1  that physically contacts a heat source formed by a heat-generating element  2  and the heat-dissipating section  43  is coupled to a heat dissipation fin section  13  of the heat dissipation module  1  whereby heat generated by the heat-generating element  2  is transferred through the heat-transfer section  42  and the heat-dissipating section  43  to heat dissipation fins that constitute the heat dissipation fin module  13 , which, together with heat dissipation airflows induced by a fan  12 , effectively dissipates heat transferred to the heat dissipation fins to the surroundings.  
         [0045]     The instant embodiment is different from the conventional heat pipe in that the heat-receiving section  41  of the gradually-expanded heat pipe  4  of the present invention comprises a primitive segment  411  and an expanded segment  412 . The primitive segment  411  is connected to the heat-transfer section  42 . The expanded segment  412  is connected to the primitive segment  411 . The expanded segment  412  is formed in a gradually-expanded structure having a cross-sectional dimension gradually increased from the connection thereof with the primitive segment  411  toward a free end.  
         [0046]     A heat-receiving section receiving slot  16  and a heat-dissipating section receiving slot  17  are formed at suitable locations of the heat conduction box  11  an the heat dissipation fin module  13  respectively. Furthermore, the heat-receiving section  41  and the heat-dissipating section  43  of the gradually-expanded heat pipe  4  are received and retained in the heat-receiving section receiving slot  16  and the heat-dissipating section receiving slot  17  of the heat dissipation module  1 , respectively.  
         [0047]     With reference to  FIG. 12 , which shows an exploded view of a heat dissipation module, also designated with reference numeral  1  for simplicity, constructed in accordance with a fourth embodiment of the present invention, the heat dissipation module  1  of the fourth embodiment comprises a gradually-expanded heat pipe, designated with reference numeral  4 ′ for distinction, to replace the gradually-expanded heat pipe  4  of the third embodiment. The gradually-expanded heat pipe  4 ′ of the fourth embodiment is different from the gradually-expanded heat pipe  4  of the third embodiment in that the heat-receiving section  41  of the gradually-expanded heat pipe  4  of the third embodiment is replaced by a heat-receiving section  41 ′ that has a gradually expanded structure. The gradually-expanded heat-receiving section  41 ′ has a cross-sectional dimension that is increased from the connection thereof with the heat transfer section  42  toward a free end.  
         [0048]     Although the present invention has been described with reference to the preferred embodiment thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.