Abstract:
A radiator includes a core unit, which includes a flow inlet which coolant enters, a flow outlet from which the coolant exits, a plurality of coolant pathways including at least an outer coolant pathway, an inner coolant pathway, a branching point, and a merging point, the outer coolant pathway being disposed to surround the inner coolant pathway, the coolant being divided at the branching point and merging at the merging point, and a connecting pathway to connect between the merging point of the outer coolant pathway and the branching point of the inner coolant pathway, wherein the flow inlet is in communication with a branching point of an outermost one of the plurality of coolant pathways, and the flow output is in communication with a merging point of an innermost one of the plurality of coolant pathways.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2010-196732 filed on Sep. 2, 2010, with the Japanese Patent Office, the entire contents of which are incorporated herein by reference. 
       FIELD 
       [0002]    The disclosures herein relate to a radiator and an electronic apparatus. 
       BACKGROUND 
       [0003]    Electronic apparatuses such as personal computers and workstations include electronic components such as a central processing unit (i.e., CPU) that generates heat. Electronic apparatuses are provided with a cooling unit for absorbing heat generated by electronic components. 
         [0004]    In a cooling unit that circulates coolant to absorb heat generated by electronic components, the coolant having an increased temperature by absorbing the heat is cooled by a radiator. For example, a heat exchanger may include a flat tube having a planar spiral shape such that adjacent tube sections are spaced at constant intervals, and coolant flows from the center to the perimeter. 
         [0005]    A fan may be provided at the core section of a radiator, and generates an air current to cool coolant flowing in the core section. In such a case, the distribution of air current speed is not even. When the distribution of speed of air currents flowing toward the core section is not taken into account, the cooling efficiency of a fan is not sufficiently high. 
       RELATED-ART DOCUMENTS 
     Patent Document 
       [0000]    
       
         [Patent Document 1] Japanese Laid-open Patent Publication No. 2005-214545 
       
     
       SUMMARY 
       [0007]    According to an aspect of the embodiment, a radiator includes a core unit, which includes a flow inlet which coolant enters, a flow outlet from which the coolant exits, a plurality of coolant pathways including at least an outer coolant pathway, an inner coolant pathway, a branching point, and a merging point, the outer coolant pathway being disposed to surround the inner coolant pathway, the coolant being divided at the branching point and merging at the merging point, and a connecting pathway to connect between the merging point of the outer coolant pathway and the branching point of the inner coolant pathway, wherein the flow inlet is in communication with a branching point of an outermost one of the plurality of coolant pathways, and the flow output is in communication with a merging point of an innermost one of the plurality of coolant pathways. 
         [0008]    According to another aspect of the embodiment, a radiator includes a core unit, which includes a flow inlet which coolant enters, a flow outlet from which the coolant exits, and a spiral-shape coolant pathway through which the coolant flows, wherein the flow inlet is in communication with an outer end of the coolant pathway, and the flow outlet is in communication with an inner end of the coolant pathway. 
         [0009]    The object and advantages of the embodiment will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 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 DRAWINGS 
         [0010]      FIG. 1  is a drawing illustrating an example of the internal structure of a personal computer according to a first embodiment; 
           [0011]      FIG. 2  is a drawing illustrating an example of the configuration of a liquid cooling unit according to the first embodiment; 
           [0012]      FIG. 3  is a perspective view of an example of a radiator according to the first embodiment; 
           [0013]      FIG. 4  is a perspective view of an example of an axial flow fan according to the first embodiment; 
           [0014]      FIG. 5  is a plan view of an example of a core unit according to the first embodiment; 
           [0015]      FIG. 6  is a perspective view of a first variation of the radiator; 
           [0016]      FIG. 7  is a perspective view of a second variation of the radiator; 
           [0017]      FIG. 8  is a perspective view of a third variation of the radiator; and 
           [0018]      FIG. 9  is a plan view of an example of a core unit according to the second embodiment. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
     First Embodiment 
       [0019]    By referring to  FIG. 1 , a description will be first given of a personal computer  100  which is an example of an electronic apparatus.  FIG. 1  is a drawing illustrating an example of the internal structure of the personal computer  100  according to the present embodiment. As illustrated in  FIG. 1 , the personal computer  100  includes an electronic component  110  and a liquid cooling unit  120 . 
         [0020]    The electronic component  110  may be an LSI (large scale integration) circuit, for example. The electronic component  110  such as an LSI circuit has a CPU (central processing unit) chip implemented therein. The CPU chip performs predetermined computations by executing an OS (operating system) and application programs. As the CPU chip performs computations, the electronic component  110  such as an LSI circuit generates heat. 
         [0021]    The personal computer  100  is provided with the liquid cooling unit  120  for absorbing heat generated by the electronic component  110 . 
         [0022]    In addition to the electronic component  110  and the liquid cooling unit  120 , the personal computer  100  includes a hard-disk drive, a DVD (digital versatile disk) drive, a card unit, and the like. The hard-disk drive stores the OS and application programs described above, for example. The DVD drive reads data from a recording medium such as a DVD, and writes data to a recording medium such as a DVD. The card unit receives a memory card, a LAN (local area network) card, or the like inserted thereinto. 
         [0023]    The liquid cooling unit  120  of the present embodiment will now be described by referring to  FIG. 2 .  FIG. 2  is a drawing illustrating an example of the liquid cooling unit  120 . As illustrated in  FIG. 2 , the liquid cooling unit  120  includes a pump  122 , a heat receiving unit  124 , and a radiator  130 . The members constituting the liquid cooling unit  120  are connected through a plurality of hoses  126  to form a circulation pathway. Coolant flowing through this circulation pathway releases heat generated by the electronic component  110  to outside the personal computer  100 . The coolant may be an antifreeze liquid of propylene glycol series, for example. 
         [0024]    The pump  122  is situated downstream relative to the radiator  130 . The pump  122  delivers the coolant to generate coolant flow inside the circulation pathway. Specifically, the pump  122  generates a coolant flow in the direction illustrated by arrows in  FIG. 2 . The pump  122  may be a piezoelectric pump. 
         [0025]    The heat receiving unit  124  is situated downstream relative to the pump  122 . As illustrated in  FIG. 1 , the heat receiving unit  124  is disposed on the electronic component  110  that generates heat. The heat receiving unit  124  absorbs heat generated by the electronic component  110 . 
         [0026]    The radiator  130  is situated downstream relative to the heat receiving unit  124 . The radiator  130  takes heat from the coolant flowing into the radiator  130 . The radiator  130  is situated in the proximity of an exhaust opening that is formed at a lateral side of the case of the personal computer  100 . The radiator  130  includes an axial flow fan  140  and a core unit  150 . The axial flow fan  140  generates an air current that goes outside trough the exhaust opening. With this arrangement, heat that the radiator  130  has taken from the coolant is released to outside the personal computer  100  through the exhaust opening. In the example illustrated in  FIG. 2 , there are two axial flow fans  140  and two core units  150 . The detailed configuration of the radiator  130  will be described later. 
         [0027]    In the liquid cooling unit  120 , the circulation pathway as described above is formed. 
         [0028]    In the following, the configuration of the radiator  130  of the present embodiment will be described by referring to  FIG. 3 ,  FIG. 4 , and  FIG. 5 . There are two axial flow fans  140  and two core units  150  illustrated in  FIG. 2 .  FIG. 3  through  FIG. 5 , however, illustrate one axial flow fan  140  and one core unit  150 .  FIG. 3  is a perspective view of an example of the radiator  130  according to the present embodiment. In  FIG. 3 , the axial flow fan  140  is simplified and illustrated in dotted lines.  FIG. 4  is a perspective view of an example of the axial flow fan  140 .  FIG. 5  is a plan view of an example of the core unit  150 . The arrows illustrated in  FIG. 5  indicate coolant flows. 
         [0029]    A description will first be given of the structure of the axial flow fan  140  of the present embodiment by referring to  FIG. 4 . As illustrated in  FIG. 4 , the axial flow fan  140  includes a plurality of blades  142 . The plurality of blades  142  rotate around a rotation axis  144 . As the plurality of blades  142  rotates around the rotation axis  144 , an air current is generated to flow from the rear side of the axial flow fan  140  to the front side thereof. 
         [0030]    In the vicinity of the rotation axis  144  of the axial flow fan  140 , the blades  142  are not in existence, so that an air current is not prominently present. Further, the speed of air currents generated by the rotation of the blades  142  is generally not even in the area where the blades  142  of the axial flow fan  140  are situated. Specifically, the air current speed increases from the rotation axis  144  toward the tips of the blades  142 . 
         [0031]    A description will be next given of the structure of the core unit  150  of the present embodiment by referring to  FIG. 5 . As illustrated in  FIG. 5 , the core unit  150  includes a flow inlet  152 , a flow outlet  154 , a plurality of coolant pathways  156 , connecting pathways  162 , and a plurality of heat dissipating fins  164 . The core unit  150  illustrated in  FIG. 5  includes five coolant pathways  156 . The coolant pathways  156  are arranged such that an outer-side coolant pathway  156  surrounds an inner-side coolant pathway  156 . 
         [0032]    The coolant flows into the core unit  150  through the flow inlet  152 . In the example illustrated in  FIG. 5 , the coolant flows in a direction perpendicular to the drawing sheet (e.g., downward) to enter the flow inlet  152 . The coolant flows out of the core unit  150  through the flow outlet  154 . In the example illustrated in  FIG. 5 , the coolant flows in a direction perpendicular to the drawing sheet (e.g., upward) upon exiting from the flow outlet  154 . 
         [0033]    The coolant pathways  156  are disposed to allow the coolant to circulate inside the core unit  150 . The shape of the coolant pathways  156  may be rectangular, for example. The shape of the coolant pathways  156  is not limited to a particular shape, and may be any shape as long as it allows the coolant to circulate inside the core unit  150 . For example, the shape of the coolant pathways  156  may be circular. 
         [0034]    The radiator  150  includes a branching point  158  and a merging point  160 . Coolant that flows into the branching point  158  is divided at the branching point  158  to flow in different directions through the coolant pathways  156 . The coolant having flown in the different directions merge at the merging point  160 . In the example illustrated in  FIG. 5 , the branching point  158  and the merging point  160  are respectively situated at the diagonally opposite corners of a rectangular-shape coolant pathway  156 . 
         [0035]    Between two adjacent coolant pathways  156 , a connecting pathway  162  connects between the merging point  160  of an outer-side coolant pathway  156  and the branching point  158  of an inner-side coolant pathway  156 . The core unit  150  illustrated in  FIG. 5  includes four connecting pathways  162 . The coolant having merged at the merging point  160  of an outer-side coolant pathway  156  runs through the connecting pathway  162 , and is then divided at the branching point  158  of an inner-side coolant pathway  156 . 
         [0036]    The heat dissipating fins  164  are disposed between adjacent coolant pathways  156 . The heat dissipating fins  164  extend in a direction parallel to the rotation axis  144  of the axial flow fan  140 . Heat generated by the electronic component  110  and absorbed by the coolant is transferred to the heat dissipating fins  164  from the coolant flowing through the coolant pathways  156 . This heat is then released to outside the personal computer  100  by the air currents generated by the axial flow fan  140 . 
         [0037]    As illustrated in  FIG. 5 , the flow inlet  152  is in communication with the branching point  158  of the outermost coolant pathway  156  among the plurality of coolant pathways  156 . Further, the flow outlet  154  is in communication with the merging point  160  of the innermost coolant pathway  156  among the plurality of coolant pathways  156 . 
         [0038]    With the arrangement described above, the coolant flowing into the core unit  150  at the flow inlet  152  is divided at the branching point  158  of the outermost coolant pathway  156  to flow in different directions through the outermost coolant pathway  156 . The coolant having flown in the different directions merge at the merging point  160  of the outermost coolant pathway  156 . The coolant having merged at the merging point  160  of the outermost coolant pathway  156  runs through the connecting pathway  162 , and is then divided at the branching point  156  of a next inner coolant pathway  156  to flow in different directions through this next inner coolant pathway  156 . After this, coolant merging at the merging point  160  and coolant separating at the branching point  158  are repeated until the coolant flows out of the core unit  150  through the flow outlet  154  after running through the merging point  160  of the innermost coolant pathway  156 . 
         [0039]    The axial flow fan  140  and the core unit  150  described heretofore are disposed such that the rotation axis  144  of the axial flow fan  140  is aligned with the center area of the core unit  150  as illustrated in  FIG. 3 . The center area of the core unit  150  refers to an area within the innermost coolant pathway  156 . In the radiator  130  of the present embodiment, the coolant pathways  156  are disposed in the core unit  150  such that the coolant flows from the outer area in which air current speed is faster to the inner area in which air current speed is slower. The outer area is at a distance in the radial direction from the rotation axis  144  and the inner area is in the proximity of the rotation axis  144 . With this arrangement, the coolant having an increased temperature by absorbing heat from the electronic component  110  first flows through the coolant pathways  156  that are disposed in the outer area of the core unit  150  in which air current speed is faster. This improves the cooling efficiency of coolant. [First Variation] 
         [0040]    A first variation of the radiator  130  will be described by referring to  FIG. 6 .  FIG. 6  is a perspective view of a first variation of the radiator  130 . The radiator  130  illustrated in  FIG. 6  includes two core units  150  and two axial flow fans  140 . The two core units  150  are arranged side by side. The axial flow fans  140  are also arranged side by side to air-cool the respective core units  150 . The configurations of the core units  150  and the axial flow fans  140  are the same as or similar to the configurations used in the first embodiment. 
         [0041]    The radiator  130  may include three or more core units  150  and three or more axial flow fans  140 . 
         [0042]    When a relatively large area is available for the radiator  130 , this variation may be suitable. According to this variation, coolant having an increased temperature due to the absorption of heat by the heat receiving unit  124  flows through a plurality of core units  150 , which further improves the cooling efficiency of coolant. 
       [Second Variation] 
       [0043]    A second variation of the radiator  130  will be described by referring to  FIG. 7 .  FIG. 7  is a perspective view of the second variation of the radiator  130 . The radiator  130  illustrated in  FIG. 7  includes two core units  150  and one axial flow fan  140 . The two core units  150  are arranged in tandem (i.e., arranged one behind the other) in the direction of air flow generated by the axial flow fan  140 . The flow inlets  152  of the two core units  150  are in communication with each other. Further, the flow outlet  154  of the two core units  150  are in communication with each other. The configurations of the core units  150  and the axial flow fans  140  are the same as or similar to the configurations used in the first embodiment. 
         [0044]    The radiator  130  may include three or more core units  150 . 
         [0045]    When a relatively small area is available for the radiator  130 , this variation may be suitable. According to this variation, coolant having an increased temperature due to the absorption of heat by the heat receiving unit  124  flows through the core units  150  that are arranged in tandem in the direction of air flow generated by the axial flow fan  140 . Accordingly, the cooling efficiency of coolant is improved even when only a relatively small area is available for the radiator  130 . 
       [Third Variation] 
       [0046]    A third variation of the radiator  130  will be described by referring to  FIG. 8 .  FIG. 8  is a perspective view of the third variation of the radiator  130 . The radiator  130  illustrated in  FIG. 8  includes two core units  150  and one axial flow fan  140 . The two core units  150  are arranged in tandem (i.e., arranged one behind the other) in the direction of air flow generated by the axial flow fan  140 , with the axial flow fan  140  intervening therebetween. The flow inlets  152  of the two core units  150  are in communication with each other. Further, the flow outlet  154  of the two core units  150  are in communication with each other. The configurations of the core units  150  and the axial flow fans  140  are the same as or similar to the configurations used in the first embodiment. 
         [0047]    The radiator  130  may include three or more core units  150 . 
         [0048]    According to this variation, as in the case of the second variation, coolant having an increased temperature due to the absorption of heat by the heat receiving unit  124  flows through the core units  150  that are arranged in tandem in the direction of air flow generated by the axial flow fan  140 . Accordingly, the cooling efficiency of coolant is improved even when only a relatively small area is available for the radiator  130 . 
       Second Embodiment 
       [0049]    In the following, the radiator  130  of a second embodiment will be described. The radiator  130  of the second embodiment differs from the radiator  130  of the first embodiment in the configuration of the core unit  150 . The remaining configurations are the same as or similar to the configurations of the first embodiment. The core unit  150  of the present embodiment will now be described by referring to  FIG. 9 .  FIG. 9  is a plan view of an example of the core unit  150  according to the present embodiment. The arrows illustrated in  FIG. 9  indicate coolant flows. 
         [0050]    As illustrated in  FIG. 9 , the core unit  150  of the present embodiment includes a flow inlet  152 , a flow outlet  154 , and a coolant pathway  156 . The coolant flows into the core unit  150  through the flow inlet  152 . In the example illustrated in  FIG. 9 , the coolant flows in a direction perpendicular to the drawing sheet (e.g., downward) to enter the flow inlet  152 . The coolant flows out of the core unit  150  through the flow outlet  154 . In the example illustrated in  FIG. 9 , the coolant flows in a direction perpendicular to the drawing sheet (e.g., upward) upon exiting from the flow outlet  154 . 
         [0051]    The coolant pathway  156  of the present embodiment has a spiral shape. As illustrated in  FIG. 9 , the flow inlet  152  is in communication with an outermost end of the coolant pathway  156 . Further, the flow outlet  154  is in communication with an innermost end of the coolant pathway  156 . 
         [0052]    With this arrangement, the coolant entering the core unit  150  via the flow inlet  152  flows from the outermost end of the coolant pathway  156  toward an inner side through the spiral-shape coolant pathway  156 . The coolant then passes through the innermost end of the coolant pathway  156  and the flow outlet  154  to flow out of the core unit  150 . 
         [0053]    Similarly to the first embodiment, the axial flow fan  140  and the core unit  150  are disposed such that the rotation axis  144  of the axial flow fan  140  is aligned with the center area of the core unit  150 . In the radiator  130  of the present embodiment, also, the coolant pathway  156  is disposed in a spiral shape in the core unit  150  such that the coolant flows from the outer area in which air current speed is faster to the inner area in which air current speed is slower. The outer area is at a distance in the radial direction from the rotation axis  144  and the inner area is in the proximity of the rotation axis  144 . With this arrangement, the coolant having an increased temperature by absorbing heat from the electronic component  110  first flows through the coolant pathway  156  that is disposed in the outer area of the core unit  150  in which air current speed is faster. This improves the cooling efficiency of coolant. 
         [0054]    According to the disclosed radiator, cooling efficiency is improved. 
         [0055]    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 embodiment(s) 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.