Abstract:
A water-cooled heat sink includes a base, a box, a propelling module, a driving module, and a plurality of conduits. The box is disposed above the base, and receives a cooled liquid. The driving module includes a first magnet. The base defines a plurality of channels. The propelling module includes a cylinder, a piston, a second magnet, and a valve. The cylinder is disposed on an inner wall of the box. The piston is disposed in the cylinder, and defines a through hole in a middle portion thereof. The second magnet is fixed to the piston. The valve is fixed in the through hole. The conduits interconnect the cylinder and the box. The first magnet can repel or attract the second magnet, thereby sliding the piston toward the cylinder to close the valve or away from the cylinder to open the valve.

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to heat sinks, and particularly, to a water-cooled heat sink. 
     2. Description of the Related Art 
     An electronic component, such as a CPU, generates considerable heat, which, if not dissipated, can degrade performance or damage the electronic component. 
     A frequently used water-cooled heat sink includes a box, a cover, a driving module, and a propelling module. The box receives a cooled liquid. The driving module and the propelling module are received in the box. The driving module is isolated from the cooled liquid, and the propelling module is immersed in the cooled liquid. The box cover seals the box at a top thereof. The box cover defines an inlet for introducing the cooled liquid and an outlet for draining the cooled liquid. The driving module includes a rotatable shaft, a stator coil, a magnet ring and a waterproof plate. The propelling module includes an impeller between the inlet and the outlet. The impeller and the magnet ring are fixed at opposite ends of the rotatable shaft. The waterproof plate is disposed between the stator coil and the magnet ring, and is connected to an inner sidewall of the box to seal the stator coil. The stator coil attracts the magnet ring to drive the impeller to rotate, such that the cooled liquid is introduced into the inlet and drained out from the outlet. However, the driving module often generates vibration during use. In time, a gap can occur between the waterproof and the inner sidewall of the box, through which cooled liquid may permeate to the stator coil, which may cause a short circuit. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE 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 disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout several views, and all the views are schematic. 
         FIG. 1  is an exploded, isometric view of a first embodiment of a water-cooled heat sink. 
         FIG. 2  is similar to  FIG. 1 , but viewed from another aspect. 
         FIG. 3  is an assembled, isometric view of the water-cooled heat sink shown in  FIG. 1 . 
         FIG. 4  is a cross-section of the water-cooled heat sink taken along line IV-IV of  FIG. 3 . 
         FIG. 5  is a cross-section of a second embodiment of a water-cooled heat sink. 
         FIG. 6  is a cross-section of a third embodiment of a water-cooled heat sink. 
         FIG. 7  is a cross-section of the water-cooled heat sink taken along line VII-VII of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , a first embodiment of a water-cooled heat sink  100  includes a base  10 , a first conduit  21 , a second conduit  22 , a driving module  30 , a box  40 , a propelling module  50 , and a box cover  60 . The box  40  is substantially rectangular and has an opening  41  at a top thereof. The box  40  defines a receiving groove  43  to receive the driving module  30  in a bottom plate of the box  40 . The box  40  is disposed on the base  10 . The box  40  further defines a water inlet hole  411  and a through hole  413  at opposite sidewalls. The water inlet hole  411  is configured to connect with the second conduit  22 . the through hole  413  is configured tom allow the first conduit  21  to pass through. The driving module  30  is fixed between the base  10  and the box  40 . The propelling module  50  is received in the box  40 . The first conduit  21  passes through the through hole  413  of the box  40 , and interconnects the base  10  and the propelling module  50 , and the second conduit  22  interconnects the base  10  and the box  40 . The box cover  60  seals the opening  41  at the top of the box  40 . 
     The base  10  includes a plurality of cooling fins  11  on the upper surface of the base  10  contacting the bottom of the box  40 . The cooling fins  11  cooperatively define a receiving portion  12  in a middle portion thereof. The base  10  further defines a plurality of channels  13  in a body of the base  10 . The channels  13  are substantially parallel. 
     Each conduit of the first conduit  21  and the second conduit  22  is a flexible tube. The first conduit  21  and the second  22  are respectively fixed to opposite sides of the base  10  to communicate with the corresponding channels  13 . The first conduit  21  includes a first guiding portion  211  and a second guiding portion  212  extending from the first guiding portion  211 . The first guiding portion  211  has a substantially a same shape with the second conduit  22 . The first guiding portion  211  interconnects the channels  13  and the through hole  413  of the box  40 , and passes through the through hole  413 . The second guiding portion  212  interconnects the propelling module  50  and the first guiding portion  211 , thereby the first conduit  21  interconnects the channels  13  of the base  10  and the propelling module  50 . The second conduit  22  interconnects the channels  13  of the base  10  and the water inlet hole  411  of the box  40 . 
     The driving module  30  includes a motor  31 , a rotor  33 , and a plurality of first magnets  35 . The motor  31  includes a rotatable shaft  312  fixed to the rotor  33 . The rotor  33  includes a through hole  331  defined in a middle portion of the rotor  33  and a plurality of fixing holes  332  defined in the rotor  33  surrounding the through hole  331 . Each first magnet  35  is received in the corresponding fixing hole  332 . A free end of the rotatable shaft  312  is fixed into the through hole  331 . In the illustrated embodiment, each first magnet  35  is a cylindrical permanent magnet. 
     The propelling module  50  includes a cylinder  51 , a plurality of second magnets  52 , a valve  53 , a piston  54 , a spring  55  and a cylinder cover  56 . The cylinder  51  is fixed in a bottom of the box  40 . The cylinder  51  defines a water outlet hole  511  corresponding to the through hole  413  or the box  40 . The water outlet hole  511  is configured to connect the first conduit  21 . Polarity of the second magnet  52  is the same as the first magnet  35 . The piston  54  defines a through hole  541 , an annular groove  542  and a plurality of fixing grooves  545 . The through hole  541  is defined in a middle portion of an end surface of the piston  54 . The annular groove  542  is defined in the end surface of the piston  54  surrounding the through hole  541 . The plurality of fixing grooves  545  is defined in the other end surface of the piston  54 . Each second magnet  52  is received in the corresponding fixing groove  545 . The valve  53  is received in the through hole  541 , and flexibly fixed to the piston  54 . The cylinder cover  56  is fixed at an open end of the cylinder  51 . The cylinder cover  56  includes a fixing portion  561  disposed at a first surface of the cylinder cover  56 . The cylinder cover  56  defines a through hole  562  in a middle portion of a second surface of the cylinder cover  56  opposite to the first surface. The spring  55  is received in the cylinder, and biases the cylinder cover  56  and the piston  54 . In the illustrated embodiment, the cylinder  51  and the box  40  are integrally formed. Each second magnet  52  is a cylindrical permanent magnet, and the through hole  541  is stepped. 
     The box cover  60  includes a base plate  61 , and a plurality of first cooling fins  63  and plurality of second cooling fins  65  disposed on opposite sides of the base plate  61 . The second cooling fins  65  are smaller than first cooling fins  63 . The second cooling fins  65  are received in the box  40 . 
     Referring to  FIG. 3 and 7 , during assembly of the water-cooled heat sink  100 , the driving module  30  is received in the receiving portion  12  of the base  10 . The box  40  is fixed on the cooling fins  11  of the base  10 . The driving module  30  is received in the receiving groove  43  of the box  40 . The valve  53  is fixed into the through hole  541 . The second magnets  52  are fixed into the fixing grooves  542  of the piston  54 . The piston  54  slides in the cylinder  51 . An end of the spring  55  is disposed in the annular groove  542 . The cylinder cover  56  is fixed at an open end of cylinder  51 . The second conduit  22  interconnects the water inlet hole  411  of the box  40  and the channels  13  of the base  10 , and the second guiding portion  212  of the first conduit  21  is received in the box  40  and connects the water outlet hole  511  of the cylinder  51 , thereby the first conduit  21  interconnects the water outlet hole  511  of the cylinder  51  of the propelling module  50  and the channels  13  of the base  10 . The box cover  60  seals the opening  41  of the box  40 , and the second cooling fins  65  are received into box  40 . 
     In use, the base  10  of the water-cooled heat sink  100  is fixed to an electronic component  102 . The electronic component  102  is fixed to a fixing plate  101 . In the illustrated embodiment, the electronic component  102  is a CPU of a computer (not shown). The fixing plate  101  is a motherboard of the computer. The cooled liquid absorbs heat produced by the electronic component  102  via the cooling fins  11  of the base  10 , and radiates the heat via the box cover  60  and the sidewalls of the box  40 . 
     Referring to  FIGS. 3 ,  4  and  7 , a function of the water-cooled heat sink  100  is described below. 
     In a first stoke, the rotor  33  of the driving module  30  rotates at a first position, where the first magnet  35  of the driving module  30  repels the second magnet  52  of the propelling module  50 . The spring  55  is elastically deformed by resisting the piston  54 . The piston  54  of the propelling module  50  slides toward the cylinder cover  56  and opens the valve  53 , whereby cooled liquid is introduced from the box  40  into the cylinder  51 . 
     In a second stoke, the rotor  33  of the driving module  30  rotates at a second position where a repellent force between the first magnet  35  and the second magnet  52  is less than the elastic force of the spring  55 . The spring  55  is again deformed. The piston  54  slides toward to the driving module  30  and closes the valve  53 , whereby cooled liquid in the cylinder  51  is drained from the water outlet hole  511  the cylinder  51  into the channels  13  of the base  10 . The liquid absorbs heat produced by the electronic components  102  via the coolings fins  11  of the base  10 , and then flow into the box  40  from the water inlet hole  411  of the box  40 , thus the liquid radiates the heat via the box cover  60  and the sidewalls of the box  40 . 
     The driving module  30  is fixed on an outer surface of the box  40 , and not contacting the propelling module  50 . The cooled liquid cannot permeate the box  40 , and the propelling module  50 , thus the driving module  30  remains dry and undamaged. 
     It is to be understood that the second magnet  52  can be an electromagnet. The spring  55  can also be omitted, whereby the piston  54  slides in the cylinder  51  by its own weight. Only one first magnet  35  and one second magnet  52  can be used instead. 
     Referring to  FIG. 5 , a second embodiment of a water-cooled heat sink  200  differs from the first embodiment of the water-cooled heat sink  100  only in that the first magnet  70  is an electromagnet replacing the driving module  30 . The first magnet  70  utilizes a unipolar pulse current, such that a repellent force is intermittently generated between the first magnet  70  and the second magnet  52 . 
     Referring to  FIG. 7 , a third embodiment of an water-cooled heat sink  300  differs from the second embodiment of the water-cooled heat sink  100  only in that the box cover  80  is a flat plate and the spring  55  is omitted. The first magnet  90  uses a bipolar pulse current, such that repellent and attraction forces are alternately generated between the first magnet  90  and the second magnet  52 . 
     Finally, while the present disclosure has been described with reference to particular embodiments, the description is illustrative of the disclosure and is not to be construed as limiting the disclosure. Therefore, various modifications can be made to the embodiments by those of ordinary skill in the art without departing from the true spirit and scope of the disclosure as defined by the appended claims.