Abstract:
Air in the first section is allowed to run into a second section through first and second air vents in an electronic apparatus. This causes an increase in the amount of airflow in the first section. In particular, if the pressure loss is larger in the first section, airflow blocked in the first section is forced to run into the second section. A smooth airflow can be established in the first section. Moreover, if the pressure in the first section is set larger than the pressure in the second section, a smoother airflow is established from the first section to the second section. A further superior airflow can be established in the first section.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an electronic apparatus such as a server computer. 
   2. Description of the Prior Art 
   A back panel stands upright in the enclosure of a server computer, for example. System board units and input/output units are respectively coupled to the front and back surfaces of the back panel through connectors, for example. A fan unit or units are incorporated in the enclosure for the purpose of cooling these units. The fan unit serves to generate airflow running in the vertical direction through first and second spaces defined along the front and back surfaces of the back panel, respectively. 
   Assume that a power source unit is mounted on the upper rack of the enclosure in the first space. The airflow generated by the fan unit collides against the bottom of the power source unit in the first space. On the contrary, the airflow is discharged out of the second space through an air outlet formed in the top of the enclosure, for example. The airflow in the first space thus suffers from a larger pressure loss. Since the pressure increases in the first space, the airflow is prevented from smoothly running in the first space. The system board units and the input/output units in the first space cannot sufficiently be cooled. 
   SUMMARY OF THE INVENTION 
   It is accordingly an object of the present invention to provide an electronic apparatus enabling a smooth airflow therein. 
   According to a first aspect of the present invention, there is provided an electronic apparatus comprising: an enclosure including a panel, the enclosure defining first and second sections therein; an outer panel attached to the outer surface of the panel, the outer panel and the panel in combination defining a third section therebetween; a first air vent formed in the panel at a position corresponding to the position of the first section, the first air vent connecting the first section to the third section; and a second air vent formed in the panel at a position corresponding to the position of the second section, the second air vent connecting the second section to the third section. 
   The electronic apparatus allows airflow in the first section to move into the second section through the first and second air vents. This results in an increase in the amount of airflow in the first section. In particular, a large pressure loss in the first section causes the blocked airflow in the first section to easily move into the second section. The airflow is allowed to smoothly run in the first section. In addition, if the pressure of the first section is set larger than the pressure of the second section, for example, the airflow in the first section smoothly runs toward the second section. The airflow runs more smoothly in the first section. 
   The electronic apparatus may further comprise a fan placed with in the enclosure, the fan generating airflow running at least in the first section. The generated airflow may run from the first air vent to the second air vent through the third section. Even though the pressure loss in the first section increases, the airflow is allowed to move into the second section. The airflow is in this manner promoted in the first section. The first section may be located in front of the second section. Alternatively, the first and second sections maybe located side by side in the horizontal direction. 
   According to a second aspect of the present invention, there is provided an electronic apparatus comprising: an enclosure including at least partly a panel defining first and second spaces, the first space having a first pressure, the second space extending in parallel with the first space and having a second pressure smaller than the first pressure; an outer panel or exterior panel attached to the enclosure, the outer panel and the panel of the enclosure in combination defining a third space therebetween; a first air vent formed in the panel of the enclosure, the first air vent connecting the third space to the first space; and a second air vent formed in the panel of the enclosure, the second air vent connecting the third space to the second space. 
   The first pressure of the first space is set larger than the second pressure of the second space in the electronic apparatus, so shat airflow smoothly moves from the first space into the second space. This results in an increase in the amount of airflow in the first space. The blocked airflow in the first space can easily move into the second space. The airflow is allowed to smoothly run in the first space in this manner. 
   According to a third aspect of the present invention, there is provided an electronic apparatus comprising: an enclosure; and an exterior panel opposed to the outer surface of the enclosure, the exterior panel utilized to define an air passage outside the enclosure, the air passage connecting the inner spaces of the enclosure. 
   The air passage is defined outside the enclosure with the assistance of the exterior panel in the electronic apparatus. The air passage connects the inner spaces of the enclosure to each other. If airflow is blocked in one of the inner spaces while airflow smoothly runs in the other inner space, the air passage serves to realize the movement of the blocked airflow toward the other inner space. This results in realization of a smooth airflow in both of the inner spaces of the enclosure. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiment in conjunction with the accompanying drawings, wherein: 
       FIG. 1  is a perspective view schematically illustrating a server computer as a specific example of an electronic apparatus according to the present invention; 
       FIG. 2  is a sectional view taken along the line  2 - 2  in  FIG. 1 ; 
       FIG. 3  is a perspective view schematically illustrating the server computer without an exterior panel; 
       FIG. 4  is a sectional view of the server computer for schematically illustrating air passages; 
       FIG. 5  is a front view of the server computer for schematically illustrating the air passages; and 
       FIG. 6  is a sectional view, corresponding to  FIG. 2 , for schematically illustrating airflow moving from a first space into a second space. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  schematically illustrates a server computer  11  as a specific example of an electronic apparatus according to the present invention. The server computer  11  includes an enclosure  12 . Input/output units  13  are mounted on the lower rack of the enclosure  12 . A PCI board is incorporated in the individual input/output unit  13 . A LAN cable is coupled to the PCI board, for example. The PCI board stands upright in the vertical direction perpendicular to the floor. 
   System board units  14  are mounted on the middle rack of the enclosure  12 . A system board is incorporated in the individual system board unit  14 . Electronic circuit elements such as a central processing unit (CPU), a memory, and the like, are mounted on a printed wiring board of the system board, for example. The CPU executes various kinds of processing based on software programs and/or data temporarily stored in the memory, for example. The system board stands upright in the vertical direction. 
   Fan units  15  are mounted on the upper rack of the enclosure  12 . The individual fan unit  15  includes axial flow fans, for example. A rotor is incorporated in the individual axial flow fan. The rotation of the rotor in the fan unit  15  generates airflow running in the enclosure  12 . The rotation axis of the rotor is set to extend in the vertical direction. The airflow thus runs in the vertical direction from the bottom of the enclosure  12  toward the top of the enclosure  12 , for example. 
   Power source unit sets  16  are mounted on the uppermost rack of the enclosure  12 . The power source unit sets  16  are arranged in four lines in the horizontal direction parallel to the floor, for example. The individual power source unit set  16  includes power source units  17  stacked in three tiers in the vertical direction, for example. The power source units  17  individually extend in the horizontal direction from the front of the enclosure  12  toward the rear of the enclosure  12  as described later. The power source units  17  serve to transform the alternating current supplied from an outlet into the direct current. 
   The enclosure  12  includes a panel at the top of the enclosure  12 , namely a top panel  12   a , extending in the horizontal direction. A first air discharge opening  18  is formed in the top panel  12   a . The first discharge opening  18  may extend widely along the front edge of the top panel  12   a , for example. A second air discharge opening  19  is formed in the top panel  12   a  at the back of the first air discharge opening  18 . The airflow generated by the fan units  15  is discharged outside through the first and second air discharge openings  18 ,  19  as described later in detail. 
   The individual power source unit  17  includes an enclosure, namely a duct  21 , defining an inner space extending in the horizontal direction from the front of the enclosure  12  toward the rear of the enclosure  12 . A fan is incorporated in the inner space of the duct  21 . The fan serves to generate airflow running from the front end of the duct  21  toward the rear end of the duct  21 . Here, the adjacent ones of the power source unit sets  16  are spaced from each other at a predetermined interval. Likewise, the outermost power source unit sets  16  are spaced from the sides of the enclosure  12  at predetermined intervals, respectively. 
   An outer panel, namely an exterior or dressing panel  22 , is attached to each side of the enclosure  12 .  FIG. 2  is a sectional view taken along the line  2 - 2  in  FIG. 1 . The downside of  FIG. 2  corresponds to the front of the server computer  11 . Referring also to  FIG. 2 , the enclosure  12  includes panels  12   b  at the sides of the enclosure  12 , namely side panels  12   b , extending in the vertical direction inside the exterior panel  22 . The exterior panel  22  is fitted into the corresponding side panel  12   b . The side panel  12   b  is opposed to the exterior panel  22  at a predetermined interval. A space  23  in the form of a flat parallelepiped is in this manner defined between the exterior panel  22  and the side panel  12   b  outside the enclosure  12 , for example. 
   A first section or first space  24  and a second section or second space  25  are defined inside the enclosure  12 . The first space  24  is defined at the foreside of the enclosure  12 . The second space  25  is defined at the backside of the enclosure  12 . The first and second spaces  24 ,  25  are located adjacent to each other. The first space  24  is defined between the top panel  12   a  and the fan units  15  at a position downstream of the axial flow fans  15   a  of the fan units  15 . The power source unit sets  16  are placed in the first space  24 . Likewise, the second space  25  is defined between the top panel  12   a  and fan units  26  at a position downstream of axial flow fans  26   a  of the fan units  26 . The fan units  26  are placed within the enclosure  12  at the backside of the enclosure  12 . The fan units  15 ,  26  may be placed at the same level above the floor. 
   First and second air vents  27 ,  28  are formed in the individual side panel  12   b . The first air vent  27  serves to connect the space  23  to the first space  24 . The second air vent  28  serves to connect the space  23  to the second space  25 .  FIG. 3  schematically illustrates the server computer  11  without the exterior panel  22 . Referring also to  FIG. 3 , the first air vent  27  is formed at a position corresponding to the position of the power source units  17  in the enclosure  12 . The first air vent  27  is opposed to the side of the duct  21  of the power source unit  17  closest to the side panel  12   b , for example. The second air vent  28  is formed at a position corresponding to the position of the second space  25 . Here, the first and second air vents  27 ,  28  may be placed at the same level above the floor. The first and second air vents  27 ,  28  may be equal in size. 
     FIG. 4  is a vertical sectional view of the server computer  11 . The arrows stand for airflow in  FIG. 4 . As shown in  FIG. 4 , an air intake opening  29  is formed in the bottom of the enclosure  12 . The air intake opening  29  is opposed to the floor. A fresh air is introduced into the inner space of the enclosure  12  through the air intake opening  29 . A back panel  31  is placed in the inner space of the enclosure  12 . The back panel  31  stands upright in the vertical direction. The system board units  14  and the input/output units  13  are coupled to the front surface of the back panel  31 . The electronic component units  32  and the input/output units  13  is coupled to the back surface of the back panel  31 . 
   The individual electronic component unit  32  includes an interface unit controlling the interface of the server computer  11  and a controller unit controlling the processing of the server computer  11 , for example. The electronic component unit  32  includes a printed wiring board extending in the horizontal direction. Here, a predetermined interval may be defined between the electronic component units  32  and the inward surface of the side panel  12   b.    
   The fan units  15  serve to generate airflow running in the vertical direction from the air intake opening  29 . The PCI boards of the input/output units  13  and the system boards of the system board units  14  stand upright in the vertical direction. The airflow thus runs in the vertical direction through the input/output units  13  and the system board units  14 . The airflow absorbs heat from the PCI boards and the electronic circuit elements in the system board units  14 . The PCI boards and the electronic circuit elements are thus prevented from a rise in temperature. The airflow then enters gaps between the power source unit sets  16 . 
     FIG. 5  is a front view of the server computer  11 . The arrows stand for airflow in  FIG. 5 . Referring also to  FIG. 5 , the airflow runs in the vertical direction between the power source unit sets  16 . The airflow is then discharged outside through the first air discharge opening  18 . 
   As shown in  FIG. 4 , the airflow collides against the bottoms of the power source units  17  in the first space  24 . This causes a change in the direction of part of the airflow. Such airflow runs in the horizontal direction between the ducts  21  and the fan units  15  from the first space  24  toward the second space  25 . The airflow is then discharged outside through the second air discharge opening  19 . 
   The fans placed within the ducts  21  allow airflow running in the horizontal direction through the power source units  17  from the front ends of the power source units  17  toward the rear ends of the power source units  17 . The airflow absorbs heat from the power source units  17 . The power source units  17  are thus prevented from a rise in temperature. The airflow runs from the rear ends of the ducts  21  toward the second space  25 . The airflow is then discharged outside through the second air discharge opening  19 . 
   The axial flow fans  26   a  of the fan units  26  generate airflow running in the vertical direction from the air intake opening  29  in the same manner as the axial flow fans  15   a  of the fan units  15 . The printed wiring boards of the input/output units  13  stand upright in the vertical direction. The airflow thus runs in the vertical direction through the input/output units  13 . The airflow absorbs heat from the electronic circuit elements on the input/output units  13 . The electronic circuit elements are prevented from a rise in temperature. 
   The airflow then runs in the vertical direction between the electronic component units  32  and the side panels  12   b . Part of the airflow runs in the horizontal direction along the printed wiring boards of the electronic component units  32 . The airflow thus absorbs heat from the electronic circuit elements on the electronic component units  32 . The electronic circuit elements are prevented from a rise in temperature. The airflow is then discharged outside through the second air discharge opening  19 . 
   The ducts  21  inevitably serve to block airflow in the first space  24 . This causes a change in the direction of the airflow. The pressure loss thus increases in the first space  24 . The airflow from the fan units  15  causes an increase in the pressure of the first space  24 . On the contrary, the airflow is smoothly discharged outside through the second air discharge opening  19  in the second space  25 . There is no increase in the pressure of the second space  25 . The pressure of the first space  24  thus gets larger than that of the second space  25 . 
   The larger pressure of the first space  24  causes the airflow in the first space  24  to move out of the enclosure  12  into the spaces  23  through the first air vents  27 , as shown in  FIG. 6 . The airflow then moves into the second space  25  through the second air vents  28 . The spaces  23  serve as air passages connecting the first space  24  and the second space  25  in this manner. The airflow is then discharged outside through the second air discharge opening  19 . 
   Since the pressure of the first space  24  is set larger than that of the second space  25  in the server computer  11 , the airflow smoothly moves out of the first space  24  into the second space  25  through the spaces  23 . The amount of the airflow increases in the first space  24 . The airflow blocked within the first space  24  can easily move into the second space  25 . The airflow is allowed to smoothly run in the first space  24 . The PCI boards  24  and the electronic circuit elements in the first space  24  can thus sufficiently be cooled. The narrow gaps between the side panels  12   b  of the enclosure  12  and the exterior panels  22  are utilized as the spaces  23 . The enclosure  12  is not required to make room for establishment of air passages. The enclosure  12  can surely be prevented from getting larger. In addition, it is not necessary to enhance the performance of the fan units  15 ,  26 . The fan units  15 ,  26  may not be replaced with ones having a higher performance. The server computer  11  is thus prevented from suffering from an increase in the production cost.