Abstract:
A radiator for dissipating heat by liquid coolant flowing includes a plate including at least two flat sections parallel to each other, a flection connecting the flat sections, a passage configured within the two flat sections and the flection to allow the liquid coolant to flow from a first opening to a second opening provided at each end of the two flat sections, the two flat sections opposed to each other, and the plate including a plurality of fins; an inlet tube having an opening formed so as to fit the first opening and an end opening for allowing the liquid coolant to flow in the passage; and an outlet tube having an opening so as to fit of the second opening and an end opening for allowing the liquid coolant to flow out the passage. The outlet tube is disposed in parallel with the inlet tube.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2008-309925, filed on Dec. 4, 2008, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The embodiments discussed herein are related to a radiator and a cooling unit. 
       BACKGROUND 
       [0003]    There are units configured to cool electronic components included within an electronic apparatus using a liquid coolant. Such units include those having a radiator for dissipating heat from the coolant. Such units are disclosed, for example, in Japanese Laid-Open Patent Publications No. 10-185466, No. 2007-170718, and No. 2007-192429. 
         [0004]    Some of radiators include a tube which allows passage of a liquid coolant or a coolant in the interior thereof and a tank connected to both ends of the tube. However, when employing the unit having the radiator as described above in a compact electronic apparatus, the employment of the unit may be difficult depending on the size of the tank of the radiator. 
       SUMMARY 
       [0005]    According to an embodiment, a radiator for dissipating heat by the use of liquid coolant flowing therein includes a plate including at least two flat sections parallel to each other, a flection connecting the flat sections, a passage configured within the two flat sections and the flection to allow the liquid coolant to flow from a first opening to a second opening provided at each end of the two flat sections, the two flat sections opposed to each other, the plate including a plurality of fins outside thereof, an inlet tube having an opening formed along a longitudinal direction thereof so as to fit the first opening and an end opening for allowing the liquid coolant to flow in the passage, and an outlet tube having an opening formed along a longitudinal direction thereof so as to fit of the second opening and an end opening for allowing the liquid coolant to flow out the passage, the outlet tube disposed in parallel with the inlet tube, wherein each longitudinal direction of the inlet tube and the outlet tube are in parallel with at least one of each surface of the two flat sections. 
         [0006]    The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
         [0007]    It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIGS. 1A to 1C  are explanatory diagrams of a laptop computer; 
           [0009]      FIG. 2  is a perspective view of the cooling unit according to an embodiment of the present invention; 
           [0010]      FIG. 3  is a diagram of an internal structure of a jacket; and 
           [0011]      FIG. 4A  is a side view of the radiator where a tube is illustrated as a section view and  FIG. 4B  is a perspective view of the radiator; and 
           [0012]      FIG. 5  is a diagram around a portion of a connecting portion between a pump and the jacket. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0013]    Referring now to the drawings, an embodiment will be described. 
         [0014]    A laptop personal computer will be described as an example of an electronic apparatus.  FIGS. 1A to 1C  are explanatory drawings of a laptop personal computer  1 . The laptop personal computer  1  includes a display portion  2  and a body portion  3  connected to each other so as to be openable and closable. The display portion  2  includes a liquid crystal display  4 . The body portion  3  includes a keyboard  5 . The body portion  3  includes various electronic components built therein.  FIGS. 1B and 1C  are a perspective view of the laptop personal computer  1  viewed from a bottom side, and  FIG. 1C  illustrates arrangement of components where a bottom cover of the body portion  3  is removed. As shown in  FIG. 1C , the body portion  3  includes a cooling unit  8  built therein. The cooling unit  8  cools electronic components in the laptop personal computer  1 .  FIG. 2  is a perspective view of the cooling unit  8  with a printed circuit board  50 . The cooling unit  8  is mounted on a printed circuit board, and includes a cooling jacket  10 , a pump  20 , a radiator  30 , and a cooling fan  40 . 
         [0015]    The cooling jacket (hereinafter, referred to as “jacket”)  10  allows a liquid coolant to flow through the interior thereof. The jacket  10  includes a case  11   a  and a lid  11   b . The case  11   a  and the lid  11   b  correspond to a casing. The case  11   a  and the lid  11   b  are formed of metal having a high thermal conductivity such as copper or aluminum, for example. The jacket  10  has a flat shape. The jacket  10  comes into abutment with electronic components such as a central processing unit (CPU)  70   b , illustrated with dotted lines, which mounted on a printed circuit board  50 . Accordingly, the heat of the electronic components is transferred to the liquid coolant flowing in the jacket  10 . 
         [0016]    The pump  20  allows circulation of the liquid coolant between the jacket  10  and the radiator  30 . The pump  20  is a motor-driven pump. The pump  20  and the jacket  10  are in communication with each other via rubber tubes  60 . The rubber tubes  60  are configured to prevent a leakage of the liquid coolant. The rubber tubes  60  are fastened by metallic belts. The pump  20  has a flat shape. 
         [0017]    The radiator  30  dissipates heat from the liquid coolant which is heated by the jacket  10 . The radiator  30  is formed of metal such as aluminum or the like, for example. The radiator  30  includes a single tube  34 , which is a plate with a passage therein, a surrounding board  36 , an exhaust tube or an outlet tube  32   a , and an introduction tube or an inlet tube  32   b . The tube  34  allows the liquid coolant to flow in the interior thereof and has a flat shape and assumes a substantially a U-shape. That is, the tube  34  includes two flat sections parallel to each other, a flection connecting the flat sections, a passage configured within the two flat sections and the flection to allow the liquid coolant to flow in the passage. The exhaust tube or outlet tube  32   a  is in communication with the other end of the tube  34 , where an opening as an end of the passage is positioned, through a side surface thereof for discharging the liquid coolant from the tube  34  through the communicating portion. The introduction tube  32   b  is in communication with one end of the tube  34 , where an opening as an end of the passage is positioned through a side surface thereof for introducing the liquid coolant to the tube  34  through the communicating portion. The surrounding board  36  surrounds the tube  34 . The exhaust tube  32   a  and the introduction tube  32   b  are respectively in communication with the jacket  10 . The exhaust tube  32   a , the introduction tube  32   b , and the jacket  10  are in communication with each other via the rubber tubes  60 . 
         [0018]    The cooling fan  40  includes an opening  41 , and has a cooling fan  42  stored in the interior thereof. When the cooling fan  42  is rotated, air is taken into the cooling fan  40  via the opening  41 , and is discharged from a vent port  46 . The vent port  46  opposes the radiator  30 . The air discharged from the vent port  46  is blown to the radiator  30 . Accordingly, the heat dissipation of the liquid coolant in the radiator  30  is accelerated. 
         [0019]    The printed circuit board  50  is a hard printed wiring board and has a predetermined patterning applied thereon. A plurality of electronic components are mounted on the printed circuit board  50 . These electronic components generate heat when power is supplied thereto. The CPU  70   b  is one of the electronic components mounted on the printed circuit board  50 . The CPU  70   b  is arranged so as to contact with the bottom of lid  11   b . Accordingly, the liquid coolant flowing in the interior of the jacket  10  receives heat from the CPU  70   b , so that the CPU  70   b  is cooled. The jacket  10 , the radiator  30 , and the cooling fan  40  are fixed onto the printed circuit board  50 . 
         [0020]    The liquid coolant is, for example, water or antifreeze solution. The antifreeze solution is water added with antifreeze liquid formulation (for example, propylene glycol) which prevents freezing of water. 
         [0021]      FIG. 3  is an explanatory drawing of an internal structure of the jacket  10  where the lid  11   b  is removed from the case  11   a  where the printed circuit board  50  is illustrated additional in order to clarify the understanding of the positional relationship between the cooling unit  8  or the jacket  10  and the printed circuit board  50 . 
         [0022]    Flow channels  12   a ,  12   b  are provided in the interior of the jacket  10 . More specifically, the flow channels  12   a ,  12   b  are provided in the case  11   a . The flow channels  12   a ,  12   b  are isolated from each other so that the flow channels  12   a  and  12   b  do not merge with each other. Projecting portions  15   a  and  16   a  are provided for trapping air bubbles in the flow channel  12   a . A fin  15   b  is provided in the flow channel  12   b  for accelerating the dissipation of heat caused by the CPU  70   b  which is disposed so as to contact with the bottom of the case  11   a.    
         [0023]    The liquid coolant is discharged from the exhaust tube  32   a  and flows through the flow channel  12   a . The liquid coolant flowing in the flow channel  12   a  is sucked by the pump  20 , and is discharged into the flow channel  12   b . The liquid coolant flowing in the flow channel  12   b  flows to the introduction tube  32   b . The liquid coolant is sucked into the tube  34 , and is discharged from the exhaust tube  32   a  to the flow channel  12   a  again. 
         [0024]    Referring to  FIGS. 4A and 4B , the radiator  30  will be described in detail.  FIG. 4A  is a side view of the radiator  30  where the tube  34  is illustrated as a section view.  FIG. 4B  is a perspective view of the radiator  30  where the fin  38  is omitted in order to clarify the understanding of the whole configuration of the radiator  30 . As illustrated in  FIG. 4A , the tube  34  includes extending portions  34   a ,  34   b , and a curved portion  34   c . The extending portion  34   b  is connected to the communicating portion of the introduction tube  32   b , and extends in a predetermined direction. The curved portion  34   c  is continued from the extending portion  34   b . The extending portion  34   a , being continued from the curved portion  34   c , extends so as to oppose the extending portion  34   b  and is connected to the communicating portion of the exhaust tube  32   a . The tube  34  is formed into a substantially U-shape when viewed from the side as illustrated in  FIG. 4A . The extending portions  34   a  and  34   b  extend in parallel to each other. 
         [0025]    The surrounding board  36  has a U-shape in side view and surrounds the tube  34 . As illustrated in  FIG. 4A , fins  38  are provided between the extending portions  34   a  and  34   b , and between the tube  34  and the surrounding board  36 . Accordingly, the efficiency of the heat dissipation of the radiator  30  is improved. The fins  38  are omitted also in  FIGS. 2 and 3  in order to clarify the understanding of the whole configuration of the radiator  30 . 
         [0026]    Since the cooling fan  40  in  FIG. 3  delivers air toward a space surrounded by the surrounding board  36  and the air passes through the interior of the surrounding board  36 , hence the efficiency of the heat dissipation of the radiator  30  is improved. 
         [0027]    Since there is only the single tube  34 , the number of connecting portions of the tube  34  with respect to the exhaust tube  32   a  and the introduction tube  32   b  is small in comparison with the case of radiators having a plurality of tubes. Therefore, the reliability of the radiator  30  is improved by the reduction of the number of connecting points. The number of components is also reduced, so that the manufacturing cost is reduced. 
         [0028]    As illustrated in  FIGS. 4A and 4B , the exhaust tube  32   a  and the introduction tube  32   b  are juxtaposed or are parallel to each other, and are arranged in the direction along a virtual extended plane of the extending portion  34   b . Accordingly, the thickness of the radiator  30  in the direction orthogonal to the virtual extended plane of the extending portion  34   a  or the extending portion  34   b  is reduced. Accordingly, the reduction of the thickness of the radiator  30  is achieved. Therefore, the radiator  30  is easily mountable on a thin electronic apparatus such as the laptop personal computer  1 . 
         [0029]      FIG. 5  is a diagrammatic illustration of a portion around a connecting portion between the pump  20  and the jacket  10  where the lid  11   b  is removed in order to clarify the understanding of the inside of the jacket  10 . The pump  20  has a suction tube  22   a  and a discharge tube  22   b . The suction tube  22   a  is in communication with the flow channel  12   a  of the jacket  10 , and the discharge tube  22   b  is in communication with the flow channel  12   b  of the jacket  10 . The liquid coolant in the interior of the flow channel  12   a  is sucked into the pump  20  through the suction tube  22   a . The sucked liquid coolant is discharged from the discharge tube  22   b  into the flow channel  12   b . As illustrated in  FIG. 5 , the suction tube  22   a  and the discharge tube  22   b  are connected to the jacket  10  via the rubber tubes  60 . The suction tube  22   a  and the discharge tube  22   b  are disposed parallel to each other. 
         [0030]    Here, oscillations of the cooling unit  8  will be described. The pump  20  sucks the liquid coolant from the suction tube  22   a , and discharges the liquid coolant from the discharge tube  22   b . In other words, a force is applied to the suction tube  22   a  from the jacket  10  side to the pump  20  side, and a force is applied to the discharge tube  22   b  from the pump  20  side to the jacket  10  side. Accordingly, the pump  20  oscillates due to the forces and the oscillations are transferred to the jacket  10 . By the oscillations of the jacket  10 , the entire cooling unit  8  oscillates. Also, the liquid coolant in the interior of the jacket  10  is introduced into the interior of the tube  34  via the introduction tube  32   b , and the liquid coolant in the interior of the tube  34  is discharged from the exhaust tube  32   a  to the jacket  10 . The jacket  10  oscillates also by the movement of the liquid coolant as described above as well. In this manner, the suction tube  22   a , the discharge tube  22   b , the exhaust tube  32   a , and the introduction tube  32   b  are oscillation sources of the jacket  10 . 
         [0031]    However, as illustrated in  FIGS. 3 and 5 , the exhaust tube  32   a  and the suction tube  22   a , and the introduction tube  32   b  and the discharge tube  22   b  are positioned substantially on the same straight line so as to extend along the same direction. Therefore, the oscillation sources of the jacket  10  are positioned on the same straight line. Accordingly, the oscillations of the jacket  10  are smaller than that where the suction tube  22   a  and the discharge tube  22   b , and the exhaust tube  32   a  and the introduction tube  32   b  are not substantially on the same straight line. Accordingly, an oscillation noise is also restrained. 
         [0032]    All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present inventions have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.