Abstract:
A non-welding cooler module includes a heat sink formed of a stack of radiation fins, a base block tightly fitted into the bottom side of the heat sink, heat pipes tightly inserted through the radiation fins and partially fitted into respective bottom open grooves of the base block with a respective flat wall portion thereof kept in flush with the bottom wall of the base block, and a thermal pad affixed to the bottom wall of the base block to hold down the heat pipes in the bottom open grooves of the base block for transferring heat energy from an external electronic chip to the heat pipes and the heat sink for quick dissipation.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    (a) Field of the Invention 
         [0002]    The present invention relates to a cooler module for cooling an electronic chip and more particularly to such a cooler module, which has its parts tightly fitted together with a thermal pad at the bottom side of the base block thereof kept in close contact with the hot part of an electronic chip for dissipation of heat energy from the electronic chip rapidly. 
         [0003]    (b) Description of the Prior Art 
         [0004]    Heat pipes are intensively used in cooler modules for cooling semiconductor chips or the like. In addition to heat tubes, a cooler module further comprises a heat sink formed of a stack of radiation fins, and a base block. The radiation fins are extruded from aluminum or copper. The heat tubes are enclosed metal tubes filled with a working fluid. The base block is an aluminum or copper block. Because the heat tubes and base block of this design of cooler module are made of different materials, a nickel plating technique is necessary so that the heat pipes and the base block can be bonded together by applying a tin solder or thermal glue. The fabrication and assembly of this cooler module is complicated, resulting in low yield rate and high manufacturing cost. Soldering between the base block and the heat tubes relatively lowers the heat transfer efficiency of the cooler module. Further, soldering the heat tubes to the base block may cause environmental pollution, not in conformity with environmental regulations. Although a copper base block has a thermal conductivity better than an aluminum base block, use of expensive copper material relatively increases the cost of the cooler module. Therefore, aluminum is commonly used for making base blocks for cooler modules. However, an aluminum base block has a relatively lower thermal conductivity relative to a copper base block. It is difficult to cut the cost while maintaining a high thermal conductivity. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention has been accomplished under the circumstances in view. According to one aspect of the present invention, the cooler module comprises a plurality of radiation fins, a plurality of heat tubes, a base block, and a thermal pad. The component parts of the cooler module are tightly fitted together. The heat tubes each have a flat wall portion exposed out of the base block and kept in flush with the bottom wall of the base block. The thermal pad is a thin sheet of metal (such as copper), and affixed to the bottom wall of the base block to cover the heat tubes partially, holding down the heat tubes on the base block for quick dissipation of heat energy from the hot part of the electronic chip to which the thermal pad is attached. 
         [0006]    According to another aspect of the present invention, the component parts of the cooler module are tightly fitted together. Upon thermal expansion, the connection of the component parts of the cooler module is enhanced, thus providing excellent heat conduction and heat dissipation performance. Because the cooler module eliminates tin soldering or nickel plating, the fabrication of the present invention does not cause environmental pollution. Therefore, the fabrication of the present invention is in conformity with environmental regulations. 
         [0007]    According to another aspect of the present invention, the base block is extruded from aluminum, and the thermal pad is extruded from copper and fixedly fastened to the bottom wall of the base block to hold down the heat pipes for quick dissipation of heat from the electronic chip to which the thermal pad is attached. Therefore, the invention effectively reduces the manufacturing cost while maintaining excellent thermal conduction. 
         [0008]    According to still another aspect of the present invention, the thermal pad can be riveted, fitted, or compression-bonded to the bottom wall of the base block to hold down the heat pipes, keeping the heat pipes, the heat sink and the base block tightly together. This assembly process is simple and inexpensive, and can hold the parts firmly together against vibration during transportation. The parts will not fall from one another upon a drastic temperature change. 
         [0009]    According to still another aspect of the present invention, the base block has a plurality of bottom open grooves, which receive the heat pipes respectively, and a plurality of clamping ribs protruded from the bottom wall and extending along two opposite sides of each of the bottom open grooves. After insertion of the heat pipes into the bottom open grooves of the base block, the clamping ribs clamp the heat pipes, holding the heat pipes firmly in the associated bottom open grooves. 
         [0010]    According to still another aspect of the present invention, the heat pipes are configured to fit the configuration of the base block, keeping the respective flat wall portion exposed to the outside of the base block for close contact with the thermal pad. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a top perspective view of a cooler module in accordance with a first embodiment of the present invention. 
           [0012]      FIG. 2  is an exploded view of the heat pipes and the base block for the cooler module in accordance with the first embodiment of the present invention. 
           [0013]      FIG. 3  is an exploded view of the cooler module in accordance with the first embodiment of the present invention. 
           [0014]      FIG. 4  is another exploded view of the heat pipes and the base block for the cooler module in accordance with the first embodiment of the present invention. 
           [0015]      FIG. 5  is a bottom perspective view of the cooler module in accordance with the first embodiment of the present invention. 
           [0016]      FIG. 6  is a cross-sectional view of the cooler module in accordance with the first embodiment of the present invention. 
           [0017]      FIG. 7  is a top perspective view of a cooler module in accordance with a second embodiment of the present invention. 
           [0018]      FIG. 8  is an exploded view of the cooler module in accordance with the second embodiment of the present invention. 
           [0019]      FIG. 9  is an elevational assembly view of the cooler module in accordance with the second embodiment of the present invention. 
           [0020]      FIG. 10  corresponds to  FIG. 9  when viewed from another angle. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    Referring to  FIG. 1 , a cooler module in accordance with a first embodiment of the present invention is shown comprised of a plurality of radiation fins  1 , a plurality of heat pipes  2 , a base block  3 , and a thermal pad  4 . 
         [0022]    The radiation fins  1  are stacked together, forming a heat sink  10 . Each radiation fin  1  has a plurality of through holes  11  for receiving the heat pipes  2  in a tight manner, and a bottom notch  12  of a predetermined profile for matching the upper part of the base block  3 . 
         [0023]    The heat pipes  2  are enclosed pipes filled with a working fluid, each having a flat wall portion  21  and fastened to the bottom side of the base block  3  and kept in flush with the bottom surface of the base block  3 . 
         [0024]    The base block  3  is a solid metal (copper or aluminum) block, having a top wall  31  that fits the bottom wall of the heat sink  10 , a plurality of bottom open grooves  32 , which receive the heat pipes  2  respectively, a plurality of clamping ribs  33  respectively longitudinally extending along two opposite sides of each of the bottom open grooves  32  for securing the heat pipes  2  to the bottom open grooves  32 . 
         [0025]    The thermal pad  4  is a thin metal (copper) sheet of good thermal conductivity fitting the bottom wall of the bottom block  3  in size and closely bonded to the bottom wall of the bottom block  3  to shield the heat pipes  2 . After installation, the two opposite sides of the thermal pad  4  are kept in close contact with the flat wall portions  21  of the heat pipes  2  and the hot part of an electronic chip (CPU or GPU; not shown). The thermal pad  4  may be bonded to the bottom wall of the bottom block  3  by means of a joint, compression bonding, or any of a variety of other conventional techniques. According to this embodiment, the thermal pad  4  has a plurality of rivet holes  41  fastened to respective rivets  34  at the bottom wall of the bottom block  3 . 
         [0026]    The aforesaid radiation fins  1 , heat pipes  2 , base block  3  and thermal pad  4  are tightly fastened together. By means of the heat expansion effect of the thermal pad  4  and the heat pipes  2 , the parts of the cooler module fit one another tightly (the thermal conductivity of the heat pipes  2  is higher than that of the thermal pad  4 ). After installation of the cooler module, the thermal pad  4  is kept in close contact with the hot part of the electronic chip to transfer heat energy from the electronic chip to the heat pipes  2  rapidly for quick dissipation. 
         [0027]    Because the parts of the cooler module fit one another tightly, the parts are firmly secured together without vibration, and the fabrication of the cooler module is easy and rapid, lowering the cost. Further, because the thermal pad  4  is kept with its large surface area in close contact with the hot part of the electronic chip, the surface contact between the thermal pad  4  and the electronic chip is reinforced upon a heat expansion. Therefore, the cooler module provides excellent thermal conduction and heat dissipation performance. Further, because the invention eliminates tin soldering, the fabrication of the cooler module does not cause environmental pollution, i.e., the invention is in conformity with environmental regulations. 
         [0028]    The clamping ribs  33  of the base block  3  are respectively disposed at two sides of each of the bottom open grooves  32 , each having a longitudinal cut  331 . By means of the longitudinal cuts  331 , the clamping ribs  33  are transversely compressible. When setting the heat pipes  2  into the respective bottom open grooves  32 , the clamping ribs  33  are radially compressed and clamped on the associated heat pipes  2  (see  FIGS. 5 and 6 ). 
         [0029]    In addition to the configuration shown in  FIGS. 1˜4 , the base block  3  can be extruded from copper in any of a variety of other shapes to match the heat pipes  2 . 
         [0030]      FIGS. 7˜10  show a cooler module in accordance with a second embodiment of the present invention. According to this embodiment, the cooler module comprises a plurality of radiation fins  1 , a plurality of heat pipes  2 , an aluminum base block  3   a , and a thermal pad  4 . The base block  3   a  is a solid metal block extruded from aluminum, having a plurality of upright fins  35   a  perpendicularly protruded from the top wall, a plurality of bottom open grooves  32   a  arranged on the bottom wall, a plurality of longitudinal cuts  321   a  respectively made in each of the two opposite ends of each of the bottom open grooves  32   a  (see  FIG. 7 ), a plurality of clamping ribs  33   a  respectively extending along two opposite sides of each of the bottom open grooves  32   a , and a plurality of longitudinal cuts  331   a  respectively formed in the clamping ribs  33   a . When heat pipes  2  are set in the bottom open grooves  32   a  of the base block  3   a , the clamping ribs  33   a  are forced to clamp the heat pipes  2 , securing the heat pipes  2  firmly to the associated bottom open grooves  32   a  (see  FIG. 8 ). The thermal pad  4  is bonded to the bottom wall of the base block  3   a  to shield the heat pipes  2 . After installation, the two opposite sides of the thermal pad  4  are kept in close contact with the flat sections  21  of the heat pipes  2  and the hot part of the electronic chip (not shown) to transfer and dissipate heat from the electronic chip. 
         [0031]    The base block  3   a  is extruded from aluminum for the advantage of low cost. The base block  3   a  matches the copper thermal pad  4 . During heat expansion, the base block  3   a  and the thermal pad  4  are tightly secured together, and the thermal pad  4  is fully kept in contact with the hot part of the electronic chip to effectively transfer heat energy from the electronic chip to the heat pipe  2 , enabling the heat pipe  2  to carry heat energy away from the electronic chip rapidly. This second embodiment is less expensive, however it achieves the same effect as the aforesaid first embodiment of the present invention. 
         [0032]    In the aforesaid first embodiment as shown in  FIGS. 1˜6 , the heat pipes  2  each have a first extension arm  22  disposed at one end and tightly fitted into the through holes  11  of the radiation fins  1  of the heat sink  10 , and a second extension arm  23  tightly fitted into the bottom wall of the base block  3  and covered by the thermal pad  4 . The flat section  21  of each heat pipe  2  is formed on the bottom wall of the second extension arm  23 . 
         [0033]    In the aforesaid second embodiment as shown in  FIGS. 7˜10 , the first and second extension arms  22  and  23  of the heat pipes  2  are respectively and tightly inserted through the radiation fins  1  of the heat sink  10 , and the U-turn  24  of each heat pipe  2  between the associated first extension arm  22  and the associated second extension arm  23  is respectively and tightly fitted into the bottom open grooves  32   a  of the base block  3   a  (the flat section  21  of each heat pipe  2  is formed on the bottom side of the associated U-turn  24 ). After setting of the U-turn  24  of each of the heat pipes  2  into the bottom open grooves  32   a  of the base block  3   a , the first and second extension arms  22  and  23  extend through the longitudinal cuts  321   a  of the bottom open grooves  32   a  respectively and the thermal pad  4  is fastened to the bottom wall of the base block  3   a  to hold down the U-turns  24  of the heat pipes  2 . 
         [0034]    A prototype of cooler module has been constructed with the features of  FIGS. 1˜10 . The cooler module functions smoothly to provide all of the features discussed earlier. 
         [0035]    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.