Abstract:
A low thermal resistance cooler module includes a heat-transfer base member defining a recess and multiple elongated, curved locating grooves, flat heat pipes set in the elongated, curved locating grooves with respective hot interfaces thereof suspending in the recess and respective cold interfaces thereof bonded to the heat-transfer base member, a heat-transfer block fixedly mounted with the hot interfaces of the flat heat pipes in the recess of the heat-transfer base member for transferring waste heat from a heat source of an external circuit board by direct contact, and connection plates respectively connected between the heat-transfer block and the heat-transfer base member.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to cooling technology for embedded system and more particularly, to a low thermal resistance cooler module for embedded system, which enables a heat-transfer block to be positively kept in contact with a heat source of a circuit board in the embedded system to evenly distribute the bearing pressure, reducing thermal resistance and facilitating quick dissipation of waste heat. 
         [0003]    2. Description of the Related Art 
         [0004]    Following fast development of technology, advanced computers having a relatively higher level of arithmetic function and faster operating speed have been continuously developed. During the operation of CPU, image processor and other electronic components of the mainboard in a high speed computer, industrial computer, computer server, embedded system or other computer design, much waste heat will be produced. In order to maintain the internal temperature of a computer in a predetermined operating temperature range, cooler modules may be used. 
         [0005]    Different sizes of cooler modules may be used to fit different heat sources (electronic components) at a circuit board in a computer. Alternatively, cooler modules of one same size may be used with different thicknesses of heat-transfer plates to fit different heat sources (electronic components) at a circuit board in a computer. However, when setting a heat-transfer plate between a cooler module and a heat source (electronic component) at a circuit board, the thermal resistance between the cooler module and the heat source (electronic component) will be relatively increased. When increasing the thickness of the heat-transfer medium, the thermal resistance will be relatively increased. 
         [0006]      FIG. 9  illustrates a conventional cooler module A. 
         [0007]    According to this prior art design, the cooler module A comprises a flat base member A 1  defining a plurality of heat pipe grooves A 11 , openings A 12  and a plurality of screw holes A 13 , a plurality of flat heat pipes A 2  set in the heat pipe grooves A 11  and fixedly bonded to the flat base member A 1 , a plurality of metal blocks A 3  bonded to respective one ends A 21  of the flat heat pipes A 2  and suspending above the openings A 12  of the flat base member A 1 , and screws A 32  respectively mounted in respective countersunk holes A 31  of the metal blocks A 3  and threaded into the screw holes A 13  at the flat base member A 1 , and compression springs A 33  respectively mounted around the screws A 32  and stopped between the metal blocks A 3  and the flat base member A 1 . 
         [0008]    The aforesaid prior art cooler module A uses the compression springs A 33  to support the metal blocks A 3  on the flat base member A 1 , enabling the metal blocks A 3  to be stopped against respective heat sources (electronic components) at an external circuit board. However, due to the arrangement of the compression springs A 33  between the metal blocks A 3  and the flat base member A 1 , the metal blocks A 3  can simply be kept in contact with the top walls of the flat heat pipes A 2 , lowering the heat transfer efficiency. Further, when the metal blocks A 3  are stopped against respective heat sources (electronic components) at an external circuit board, the pressure from the respective heat sources (electronic components) may not be evenly distributed through the metal blocks A 3  to the flat heat pipes A 2  and the compression springs A 33 , causing metal block surface damage and affecting structural stability. Further, when setting the compression springs A 33  between the countersunk holes A 31  of the metal blocks A 3  and the flat base member A 1  during installation, the compression springs A 33  must be kept compressed, making installation much more difficult. An improvement in this regard is desired. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention has been accomplished under the circumstances in view. It is therefore one object of the present invention to provide a low thermal resistance cooler module, which enables a heat-transfer block to be positively kept in contact with a heat source of a circuit board in an embedded system to evenly distribute the bearing pressure, reducing thermal resistance and facilitating quick dissipation of waste heat. 
         [0010]    To achieve this and other objects of the present invention, a low thermal resistance cooler module comprises a heat-transfer base member defining a recess and multiple elongated, curved locating grooves, flat heat pipes set in the elongated, curved locating grooves with respective hot interfaces thereof suspending in the recess and respective cold interfaces thereof bonded to the heat-transfer base member, a heat-transfer block fixedly mounted with the hot interfaces of the flat heat pipes in the recess of the heat-transfer base member for transferring waste heat from a heat source of an external circuit board by direct contact, and connection plates respectively connected between the heat-transfer block and the heat-transfer base member. Further, a the heat sink is attached to a rectangular locating groove at the heat-transfer base member to hold down one flat heat pipe in one elongated, curved locating groove of the heat-transfer base member. By means of supporting the heat-transfer block on the connection plates above the recess of the heat-transfer base member, the heat-transfer block can be positively kept in contact with an external heat source at an external circuit board to absorb and transfer waste heat from the external heat source efficiently during operation of the external circuit board, enhancing quick heat dissipation. 
         [0011]    Further, the heat sink comprises a heat-transfer plate arranged at the top side thereof; the heat-transfer block comprises a heat-transfer plate of a phase change material arranged at the top side thereof. Subject to the arrangement of the heat-transfer plate of the heat sink and the heat-transfer plate of the heat-transfer block, the heat sink and the heat-transfer block can be kept in contact with heat sources of an external circuit board positively, compensating any manufacturing tolerances or uneven component surfaces. Subject to the structural design of the heat-transfer base member and the heat-transfer block and the arrangement of the heat-transfer base member, the heat-transfer block, the flat heat pipes and the connection plates, the vertical thickness of the low thermal resistance cooler module can be minimized, providing a low profile characteristic. 
         [0012]    Further, the heat-transfer block comprises a plurality of vertical screw holes respectively formed in respective mounting portions thereof. Further, the heat-transfer base member comprises a plurality of mating connection structures each comprising a screw hole. Further, each connection plate comprises a circular through hole at a first connection end thereof and an oblong through hole at a second end thereof. Further, the circular through holes and oblong through holes of the connection plates are respectively affixed to the vertical screw holes in the mounting portions of the heat-transfer block and the screw holes of the mating connection structures of the heat-transfer base member by by respective screws. 
         [0013]    Further, the heat sink and the heat-transfer block are made of aluminum or copper alloy. When the low thermal resistance cooler module is installed in a circuit board to keep the heat sink and the heat-transfer block in positively contact with respective heat sources of the circuit board, the heat sink and the heat-transfer block absorb waste heat from the heat sources and transfer absorbed waste heat to the flat heat pipes, wherein, the liquid in the hot interface of each flat heat pipe turns into a vapor by absorbing heat from the hot interface; the vapor then travels along the respective flat heat pipe to the cold interface, condenses back into a liquid, releasing the latent heat; the liquid then returns to the hot interface through a capillary action where it evaporates once more and repeats the cycle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is an oblique elevational view of a low thermal resistance cooler module in accordance with the present invention. 
           [0015]      FIG. 2  is an exploded view of the low thermal resistance cooler module in accordance with the present invention. 
           [0016]      FIG. 3  corresponds to  FIG. 2  when viewed from another angle. 
           [0017]      FIG. 4  is a sectional side view of the low thermal resistance cooler module in accordance with the present invention. 
           [0018]      FIG. 5  is an exploded view illustrating an application example of the low thermal resistance cooler module in accordance with the present invention. 
           [0019]      FIG. 6  is a schematic sectional applied view of the present invention, illustrating the low thermal resistance cooler module attached to the circuit board. 
           [0020]      FIG. 7  corresponds to  FIG. 6 , illustrating the low thermal resistance cooler module and the circuit board affixed together. 
           [0021]      FIG. 8  is an exploded view of an alternate form of the low thermal resistance cooler module in accordance with the present invention. 
           [0022]      FIG. 9  is an oblique elevational view of a cooler module according to the prior art. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]    Referring to  FIGS. 1-4 , a low thermal resistance cooler module for embedded system in accordance with the present invention is shown. The low thermal resistance cooler module comprises a heat-transfer base panel  1 , a plurality of flat heat pipes  2 , a heat sink  22 , a heat-transfer block  3 , and a plurality of connection plates  4 . 
         [0024]    The heat-transfer base member  1  comprises a flat base panel  11 , a recess  12  located at the top wall of the flat base panel  11 , a plurality of mating connection structures  13  located at the top wall of the flat base panel  11  around the recess  12 , an opening  121  cut through the recess  12 , a plurality of elongated, curved locating grooves  14  located at the top wall of the flat base panel  11  and extended from the opening  121  in the recess  12  for accommodating the flat heat pipes  2 , a rectangular locating groove  141  located at the top wall of the flat base panel  11  across which one of elongated, curved heat pipe grooves  14  extends, and a plurality of upright female screw rods  15  extended from the top wall of the flat base panel  11  around the border area thereof. Each mating connection structure  13  comprises a positioning groove  132  extended from the recess  12 , and a screw hole  131  disposed adjacent to the locating groove  132  remote from the recess  12 . 
         [0025]    The flat heat pipes  2  are respectively set in the elongated, curved heat pipe grooves  14 , each having two opposing end portions  21 , one forming a hot interface and other forming a cold interface. 
         [0026]    The heat sink  22  is bonded to the rectangular locating groove  141  of the heat-transfer base member  1  to hold down one flat heat pipe  2 , having a positioning groove  221  defined in the bottom side thereof and tightly attached to the flat heat pipe  2  and a heat-transfer plate  23  arranged at the top side thereof. 
         [0027]    The heat-transfer block  3  is a rectangular block comprising a plurality of mounting portions  31  around the border area thereof, a stepped bottom groove  312  located at the bottom side of each mounting portion  31 , a plurality of vertical screw holes  311  respectively formed in the mounting portions  31  in communication with the respective stepped bottom grooves  312 , a positioning groove  32  defined in the bottom side thereof and tightly attached to one end portion  21  of each of the flat heat pipes  2 , and a heat-transfer plate  33  of a phase change material arranged at the top side thereof. 
         [0028]    The connection plates  4  each comprises opposing first connection end  41  and second connection end  42 , a circular through hole  411  located at the first connection end  41  for the mounting of one respective tie screw  412 , and an oblong through hole  421  located at the second connection end  42  for the mounting of one respective lock screw  422 . 
         [0029]    During installation of the low thermal resistance cooler module, set the flat heat pipes  2  in the elongated, curved heat pipe grooves  14  at the flat base panel  11  of the heat-transfer base member  1  to suspend one end portion  21  of each of the flat heat pipes  2  in the opening  121  in the recess  12  of the heat-transfer base member  1 , and then bond the other end portion  21  of each of the flat heat pipes  2  to the flat base panel  11  of the heat-transfer base member  1  by welding, and then attach the heat-transfer block  3  to the recess  12  over the opening  121  to keep the positioning groove  32  in close contact with the respective end portions  21  of the flat heat pipes  2  and bond the respective end portions  21  of the flat heat pipes  2  and the heat-transfer block  3  together by welding, and then attach the heat sink  22  to the rectangular locating groove  141  of the heat-transfer base member  1  to have one flat heat pipe  2  be tightly received in the positioning groove  221  and bonded to the heat sink  22  by welding. It is to be understood that the aforesaid welding technique to affix the heat-transfer base member  1 , the heat pipes  2 , the heat sink  22  and the heat-transfer block  3  together is simple an application example of the present invention, other fastening technique or means or thermal adhesive may be used to achieve the same effect. 
         [0030]    Thereafter, install the connection plates  4  to connect the respective first connection ends  41  and second connection ends  42  to the mounting portions  31  of the heat-transfer block  3  and the mating connection structures  13  of the heat-transfer base member  1 . At this time, insert the first connection ends  41  of the connection plates  4  into the respective stepped bottom grooves  312  in the mounting portions  31  of the heat-transfer block  3 , and then insert the respective tie screws  412  upwardly from the opening  121  of the heat-transfer base member  1  through the circular through holes  411  at the respective first connection ends  41  of the connection plates  4  and thread the respective tie screws  412  into the respective vertical screw holes  311  in the mounting portions  31  of the heat-transfer block  3 , and then insert the respective lock screws  422  downwardly through the respective oblong through holes  421  at the second connection ends  42  of the connection plates  4  and thread the respective lock screws  422  into the screw holes  131  of the respective mating connection structures  13  of the heat-transfer base member  1 . Thus, the heat-transfer block  3  is supported on the connection plates  4  at the heat-transfer base member  1 . 
         [0031]    As stated above, the first connection ends  41  and second connection ends  42  of the connection plates  4  are respectively fastened to the mounting portions  31  of the heat-transfer block  3  and the respective mating connection structures  13  of the heat-transfer base member  1  by tie screws  412  and lock screws  422 . However, in actual application, welding, riveting, thermal adhesive bonding and other fastening techniques may be selectively used to achieve the same effect. 
         [0032]    Further, in the aforesaid application example, tie screws  412  are inserted upwardly from the opening  121  of the heat-transfer base member  1  through the circular through holes  411  at the respective first connection ends  41  of the connection plates  4  and threaded into the respective vertical screw holes  311  in the mounting portions  31  of the heat-transfer block  3 . Alternatively, the heat-transfer base member  1  can be configured without the aforesaid opening, and the tie screws  412  can be inserted upwardly through respective through holes (not shown) at the heat-transfer base member  1  and the circular through holes  411  at the respective first connection ends  41  of the connection plates  4  and threaded into the respective vertical screw holes  311  in the mounting portions  31  of the heat-transfer block  3 . 
         [0033]    Referring to  FIGS. 5 ,  6  and  7 , the low thermal resistance cooler module can be attached to a circuit board  5  to dissipate heat from electronic components at the circuit board  5 . As illustrated, the circuit board  5  comprises a plurality of heat sources  51  that can be a CPU, image processor, chip module or any other electronic component. The low thermal resistance cooler module is attached to a circuit board  5  to keep the heat-transfer plate  23  of the heat sink  22  and the heat-transfer plate  33  of the heat-transfer block  3  in close contact with the heat sources  51  of the circuit board  5 , and then respective screws  53  are inserted through respective mounting through holes  52  at the circuit board  5  and into the respective female screw rods  15  of the heat-transfer base member  1  to affix the heat-transfer base member  1  and the circuit board  5  together. After installation, the circuit board  5  is supported on the female screw rods  15  and kept at a distance from the flat base panel  11  of the heat-transfer base member  1 , and therefore, open spaces are provided between the heat-transfer base member  1  and the circuit board  5  around the heat sink  22  and the heat-transfer block  3  for air circulation. Subject to the arrangement of the heat-transfer plate  23  of the heat sink  22  and the heat-transfer plate  33  of the heat-transfer block  3 , the heat sink  22  and the heat-transfer block  3  can be kept in contact with the heat sources  51  of the circuit board  5  positively, compensating any manufacturing tolerances or uneven component surfaces. Further, after a phase change of the phase change material of the heat-transfer plate  33  of the heat-transfer block  3 , the liquefied compound of the phase change material flows evenly within the pressed area that covers the whole working area of the respective heat source  51 . This phase change material functions as a thermal paste, but it does not flow over unexpected area. 
         [0034]    Further, when the low thermal resistance cooler module and the circuit board  5  are attached together, one heat source  51  of the circuit board  5  is stopped against the heat-transfer plate  33  of the heat-transfer block  3  to impart a pressure to the heat-transfer block  3  in direction toward the recess  12  of the heat-transfer base member  1 . Because the connection plates  4  are suspending in the opening  121  of the heat-transfer base member  1  and have the first connection ends  41  and second connection ends  42  thereof respectively fastened to the mounting portions  31  of the heat-transfer block  3  and the respective mating connection structures  13  of the heat-transfer base member  1  by the tie screws  412  and the lock screws  422 , the connection plates  4  buffer the pressure imparted by the circuit board  5  to the heat-transfer block  3  in direction toward the recess  12  of the heat-transfer base member  1 , ensuring positive contact between the heat-transfer block  3  and the respective heat source  51  of the circuit board  5  that is stopped against heat-transfer plate  33 . Subject to the structural design of the heat-transfer base member  1  and the heat-transfer block  3  and the arrangement of the heat-transfer base member  1 , the heat-transfer block  3  and the connection plates  4 , the vertical thickness of the low thermal resistance cooler module can be minimized, providing a low profile characteristic. 
         [0035]    Further, the heat sink  22  and the heat-transfer block  3  can be made of aluminum or copper alloy. During operation of the heat sources  51  of the circuit board  5 , the heat sink  22  and the heat-transfer block  3  absorb waste heat from the heat sources  51  and transfer absorbed waste heat to the heat pipes  2 , wherein, the liquid in one end portion  21  (hot interface) of each of the flat heat pipes  2  turns into a vapor by absorbing heat from that end portion  21 ; the vapor then travels along the respective flat heat pipes  2  to the other end portions  21  (cold interface), condenses back into a liquid, releasing the latent heat; the liquid then returns to the hot interface through a capillary action where it evaporates once more and repeats the cycle. 
         [0036]    Referring to  FIG. 8  and  FIGS. 2 ,  5  and  7  again, the connection plates  4  are flat, elongated metal plate members. The design of the oblong through hole  421  at the second connection end  42  of each connection plate  4  allows each connection plate  4  to be moved relative to the respective lock screw  422  to adjust the position. Further, in order to enhance the flexibility of the connection plates  4 , each connection plate  4  can be made having an S-shaped, W-shaped, or zigzag-shaped, elastically deformable body connected between the first connection end  41  and second connection end  42  thereof. 
         [0037]    Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.