Abstract:
A refrigerator includes a main body provided with storage chambers having doors, one of the doors being provided with an opening, the opening having at least one stepped plane; a rack installed in the storage chamber at a height corresponding to that of the lower end of the opening; a sub door to open and close the opening; and a connection member to prevent a height difference between a rear surface of the sub door and the opening. The connection member is configured to slide relative to the sub door to cover the at least one stepped plane, whereby the connection member closes the at least one stepped plane when the sub door is closed, and opens the at least one stepped plane when the sub door is opened so that the rear surface of the sub door and the connection member form substantially a level plane with the rack.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. application Ser. No. 12/805,918 filed on Aug. 24, 2010, which claims the benefit of Korean Patent Application No. 10-2009-0101910, filed on Oct. 26, 2009 in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    1. Field 
         [0003]    Embodiments relate to a refrigerator having a sub door which is installed on a main door so as to allow articles stored in a storage chamber to be withdrawn without opening of the main door and serves as a homebar door. 
         [0004]    2. Description of the Related Art 
         [0005]    In general, a refrigerator is an apparatus which stores frozen food and refrigerated food in a fresh state within storage chambers by controlling temperatures of the storage chambers by circulating cool air generated from a refrigerating cycle. 
         [0006]    Doors to open and close the storage chambers rotated forwards are installed on a main body of such a refrigerator, and a homebar door (hereinafter, referred to as a sub door), through which articles stored in the storage chambers is withdrawn to the outside without opening of the doors, or, which is horizontally supported when the sub door is opened such that the stored articles are temporarily mounted on the sub door, is provided on the doors. 
         [0007]    The conventional refrigerator having the sub door includes a receipt space provided on the rear surface of the door of the refrigerator and communicated with the outside through an opening formed through the door, the sub door installed at the opening such that the front end of the sub door is vertically rotatable about the lower end of the sub door so as to selectively open and close the receipt space, and stoppers provided on both side surfaces of the opening and supporting the lower ends of both sides of the rear surface of the sub door under the condition that the opening is opened so as to restrict the range of rotation of the sub door. 
         [0008]    The above conventional refrigerator generates heat loss at the sub door, thus increasing energy loss compared with a refrigerator without a sub door. Further, the temperature of a portion around the sub door at the inside of the storage chamber is relatively high, and thus storage performance of the refrigerator is lowered. 
       SUMMARY 
       [0009]    Therefore, it is an aspect to provide a refrigerator having a sub door which reduces energy loss. 
         [0010]    It is another aspect to provide a refrigerator having a sub door which improves storage performance of a storage chamber. 
         [0011]    It is a further aspect to provide a refrigerator having a sub door which transmits cool air to a stored article, if the sub door is opened and the article is placed on the opened sub door. 
         [0012]    Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention. 
         [0013]    In accordance with one aspect, a refrigerator includes a main body provided with storage chambers formed therein, doors opening and closing the storage chambers, and provided with an opening, a sub door to open and close the opening, and a cooling unit provided on the rear surface of the sub door. 
         [0014]    The cooling unit may be made of a metal having a high heat capacity. 
         [0015]    The cooling unit may be made of stainless steel. 
         [0016]    The cooling unit may include a cold storage pack containing a liquid material, the phase of which is changeable. 
         [0017]    The refrigerator may further include a rack installed in the storage chambers at a height corresponding to that of the lower end of the opening, and a connection member to prevent a height difference between the rear surface of the sub door and the opening when the sub door is opened. 
         [0018]    The connection member may slide on the rear surface of the sub door based on opening and closing of the sub door. 
         [0019]    The cooling unit may include a first stepped plane, and a second stepped plane lower than the first stepped plane, and the connection member may slide relative to the sub door and thus close the second stepped plane, when the sub door is closed, and may slide relative to the sub door and thus open the second stepped plane, when the sub door is opened. 
         [0020]    The refrigerator may be a kimchi refrigerator to store kimchi. 
         [0021]    The storage chambers provided in plural number may be vertically divided from each other, and the sub door may be provided on the door to open and close the upper storage chamber out of the plural storage chambers. 
         [0022]    The storage chambers provided in plural number may be horizontally divided from each other, the number of the doors may be equal to the number of the storage chambers, and the sub door may be provided on at least one door of the doors. 
         [0023]    The sub door may have a width corresponding to that of the doors. 
         [0024]    In accordance with another aspect, a refrigerator includes a main body provided with storage chambers formed therein, doors opening and closing the storage chambers, and provided with an opening, and a sub door has a width corresponding to that of the doors so as to open and close the opening, wherein the sub door includes a first plane contacting the edge of the opening, a second plane protruded from the first plane and inserted into the opening, and a cooling unit provided on the second plane and made of a material having a higher heat capacity of an injection molded product. 
         [0025]    In accordance with a further aspect, a manufacturing method of a sub door to open and close an opening of a door of a refrigerator includes preparing a frame having a size corresponding to the opening, and provided with front and rear openings on the front and rear surfaces thereof, fixing a front panel forming the front surface of the sub door to the edge of the front opening of the frame, fixing a cooling unit made of a material having a higher heat capacity than an injection molded product to the rear opening of the frame, and filling the inside of the sub door formed by the frame, the front panel, and the cooling unit with a foamed material so as to attach the frame, the front panel, and the cooling unit to each other by means of the foamed material. 
         [0026]    The fixing of the front panel to the edge of the front opening of the frame may be achieved by attaching the front panel to the edge of the front opening using a double-sided adhesive tape. 
         [0027]    The fixing of the cooling unit to the rear opening of the frame may be achieved by attaching the cooling unit to the edge of the rear opening using a double-sided adhesive tape 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which: 
           [0029]      FIG. 1  is a perspective view illustrating a schematic configuration of a refrigerator in accordance with one embodiment; 
           [0030]      FIG. 2  is a perspective view of a main door of the refrigerator in accordance with the embodiment, from which a sub door is separated; 
           [0031]      FIG. 3  is a longitudinal-sectional view of the refrigerator in accordance with the embodiment, illustrating the sub door in a closed state; 
           [0032]      FIG. 4  is a longitudinal-sectional view of the refrigerator in accordance with the embodiment, illustrating the sub door in an opened state; 
           [0033]      FIG. 5  is an exploded perspective view of the sub door illustrating a manufacturing method of the sub door in accordance with the embodiment; and 
           [0034]      FIG. 6  is a perspective view illustrating a schematic configuration of a refrigerator in accordance with another embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    Reference will now be made in detail to the embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
         [0036]    Hereinafter, a refrigerator in accordance with one embodiment will be described with reference to the accompanying drawings. 
         [0037]      FIG. 1  is a perspective view illustrating a schematic configuration of a refrigerator in accordance with one embodiment,  FIG. 2  is a perspective view of a main door of the refrigerator in accordance with the embodiment, from which a sub door is separated, and  FIG. 3  is a longitudinal-sectional view of the refrigerator in accordance with the embodiment, illustrating the sub door in a closed state. 
         [0038]      FIG. 4  is a longitudinal-sectional view of the refrigerator in accordance with the embodiment, illustrating the sub door in an opened state, and  FIG. 5  is an exploded perspective view of the sub door illustrating a manufacturing method of the sub door in accordance with the embodiment. 
         [0039]    The refrigerator in accordance with this embodiment, as shown in  FIG. 1 , includes a main body  10 , the inside of which is divided into storage chambers  11 ,  12 , and  13 , and the storage chambers  11 ,  12 , and  13  within the main body  10  include an upper storage chamber  11 , a central storage chamber  12 , and a lower storage chamber  13 , which are vertically divided from each other. First to third storage chamber doors  20 ,  14 , and  15  to open and close the respective storage chambers  11 ,  12 , and  13  are installed on the front surface of the main body  10 . 
         [0040]    The main body  10  is formed in a box shape filled with a urethane foamed material, and a machinery chamber (not shown) in which various electric components are installed is provided at a rear region of the lower portion of the main body  10 . Components of a refrigerating cycle, such as a compressor (not shown), a condenser (not shown) to condense a refrigerant in a high-temperature and high-pressure state discharged from the compressor, and a control box (not shown), are installed in the machinery chamber in the same manner as a conventional refrigerator. 
         [0041]    The refrigerator in accordance with this embodiment may be an indirect type refrigerator in which an evaporator (not shown) is installed at the rear portion of a storage chamber to supply cool air, heat-exchanged with the evaporator, to the storage chamber, or may be a direct type refrigerator in which a refrigerant pipe of an evaporator is wound on the external surface of a storage chamber to supply heat of the evaporator directly to the storage chamber. 
         [0042]    A configuration of such a refrigerating cycle is well known in general, and a detailed description thereof will thus be omitted. 
         [0043]    The first storage chamber door  20 , the second storage chamber door  14 , and the third storage chamber door  15  are respectively provided on the front surfaces of the first to third storage chambers  11 ,  12 , and  13 . The first storage chamber door  20  is hinged to the main body  10  and is rotated to open and close the first storage chamber  11 , and the second and third storage chamber doors  14  and  15  are slidably provided on the main body  10  and are slid to open and close the second and third storage chambers  12  and  13 . 
         [0044]    A plurality of racks  16   a,    16   b  and  16   c  vertically dividing the inside of the first storage chamber  11  to efficiently and separably store various articles is disposed in the first storage chamber  11 . A sub door  30  to allow stored articles to be withdrawn without opening of the first storage chamber door  20 , which opens and closes an opening  11   a  of the first storage chamber  11 , is provided in front of one storage space  17  of storage spaces divided from each other by the plural racks  16   a,    16   b  and  16   c.    
         [0045]    The lower rack  16   c  maintains a height about equal to that of the height of the rear surface of the sub door  30  when the sub door  30  is opened, thereby enabling articles stored in the storage space  17  to be easily withdrawn. 
         [0046]    The sub door  30  serves to enable the articles stored in the first storage chamber  11  to be withdrawn without opening of the first storage chamber door  20 . An opening  21  having a size corresponding to the sub door  30  is formed through the first storage chamber door  20  so as to allow the storage space  17  formed by the racks  16   b  and  16   c  to be communicated with the outside, when the sub door  30  is opened. 
         [0047]    A stepped part  22  wider than the opening  21  by a designated width is provided at the edge of the front portion of the opening  21 . 
         [0048]    Hinge holes  22   a  to rotatably fix the sub door  30  are formed at the lower portions of the side surfaces of the stepped part  22 , and a hook insertion hole  22   b  to allow the sub door  30  to be opened and closed is formed on the upper portion of the stepped part  22 . The rear surface portion of the sub door  30  is formed in a size and a shape corresponding to the opening  21 , and the front surface portion of the sub door  30  is formed in a size corresponding to the stepped part  22 . 
         [0049]    Hinge protrusions  31   a  corresponding to the hinge holes  22   a  of the stepped part  22  are formed on the lower ends of the side surfaces of the sub door  30 , and a hook  31   b  corresponding to the hook insertion hole  22   b  is formed on the upper portion of the rear surface of the sub door  30  so as to allow the sub door  30  to be opened and closed. 
         [0050]    The sub door  30  is vertically rotated to be opened and closed. When the sub door  30  is opened, the sub door  30  is supported in the horizontal direction and functions as a rack on which food is placed. 
         [0051]    The sub door  30  is hinged to the stepped part  22 , and the upper end of the sub door  30  is rotated about the lower end of the sub door  30 , thereby opening and closing the opening  21 . 
         [0052]    The sub door  30 , as shown in  FIG. 5 , includes a frame  32  provided with closed upper, lower, left, and right surfaces and openings  37  and  36  formed on front and rear surfaces thereof, a front panel  33  closing the front opening  37  of the frame  32  and forming the front surface of the sub door  30 , a cooling unit  50  closing the rear opening  36  of the frame  32  and made of a material having a higher heat capacity than the frame  32  made of an injection molded product, and a connection member  40  (with reference to  FIG. 2 ) slidably provided on the rear surface of the sub door  30  to prevent a height difference between the opening  21  and the rear surface of the sub door  30  when the sub door  30  is opened. 
         [0053]    For example, the front panel  33  is made of tempered glass printed with a decorative pattern. Further, the front panel  33  may be made of metal or other materials. 
         [0054]    The frame  32  is obtained by injection molding using a resin material. As shown in  FIG. 5 , the front panel  33  is attached to the edge of the front opening  37 , and the cooling unit  50  is attached to the edge of the rear opening  36 . 
         [0055]    Double-sided adhesive tapes or other adhesive materials are provided on the edges of the front opening  37  and the rear opening  36 , thereby fixing the front panel  33  and the cooling unit  50  to the frame  32 . 
         [0056]    A foamed material fills the above sub door  30 , thereby forming a heat insulating layer. 
         [0057]    Further, the frame  32  includes a first plane  34  contacting the stepped part  22  of the opening  21 , and a second plane  35  protruded from the first plane  34  and inserted into the opening  21 . 
         [0058]    The connection member  40  is disposed on the lower portion of the rear surface of the sub door  30  such that the connection member  40  is vertically slidable. A pair of bending parts  41  which is bent downwardly so as to surround the rear surface of the sub door  30  is formed on both sides of the connection member  40 , and guide protrusions  42  to guide the sliding movement of the connection member  40  relative to the rear surface of the sub door  30  are provided on the inner surfaces of the upper portions of the bending parts  41 . 
         [0059]    Guide holes  31   c  elongated to guide the rectilinear movement of the guide protrusions  42  of the connection member  40  are provided on both sides of the rear surface of the sub door  30 . 
         [0060]    Rotating protrusions  43  to rotatably fix the connection member  40  are formed on the outer surfaces of the lower portions of the bending parts  41  of the connection member  40 . Rotating holes  21   a  corresponding to the rotating protrusions  43  are formed at the lower portions of both side surfaces of the opening  21 . 
         [0061]    Therefore, when the sub door  30  is vertically rotated, the connection member  40  is vertically rotated in connection with the rotation of the sub door  30 , and performs a vertical sliding movement relative to the rear surface of the sub door  30 . 
         [0062]    The cooling unit  50  may be a cooling plate  51  made of a metal panel having a higher heat capacity than the resin material. For example, the cooling plate  51  is made of stainless steel. 
         [0063]    The cooling plate  51  is mounted on the second plane  35  of the frame  32 , and is exposed to the outside. 
         [0064]    The cooling plate  51  includes a first stepped plane  51   a,  and a second stepped plane  51   b  lower than the first stepped plane  51   a.  The connection member  40  performs the sliding movement along the second stepped plane  51   b.    
         [0065]    Therefore, when the sub door  30  is closed, the connection member  40  performs the sliding movement relative to the sub door  30  and thus closes the second stepped plane  51   b,  and when the sub door  30  is opened, the connection member  40  performs the sliding movement relative to the sub door  30  and thus opens the second stepped plane  51   b.    
         [0066]    The cooling unit  50  further includes a cold storage pack  52  containing a liquid material, the phase of which is changeable. 
         [0067]    The liquid material, i.e., a cold storage material, is a liquid material, the phase of which is changeable. Alcohol, an aqueous sodium chloride solution, a chemical material containing polyethylene glycol or polyvinyl alcohol, or a mixture of the chemical material and water or alcohol may be used as the cold storage material. Further, a metal or a solid material having high specific heat and thermal conductivity may be used as the cold storage material. 
         [0068]    The cold storage pack  52  is provided integrally with or separately from the cooling unit  50 , and then is fixed to the frame  32 . 
         [0069]    Therefore, when the sub door  30  is opened, if a stored article is placed on the rear surface of the opened sub door  30 , the cooling unit  50  provided on the sub door  30  transmits cool air of the article placed on the rear surface of the sub door  30 . 
         [0070]    Further, when the sub door  30  is closed, the cooling unit  50  lowers the temperature of the opening  21  of the door  20  which is relatively high, thereby achieving relatively uniform temperature distribution in the storage chamber and thus improving storage performance of the refrigerator. 
         [0071]    Now, a manufacturing method of the sub door of the refrigerator in accordance with this embodiment will be described. 
         [0072]    First, the frame  32  provided with the front and rear openings  37  and  36  on the front and rear surfaces thereof and having a size corresponding to the door  20  is prepared, the front panel  33  forming the front surface of the sub door  30  is fixed to the edge of the front opening  37  of the frame  32 , the cooling unit  50  made of a material having a higher heat capacity than the injection molded product forming the frame  32  is fixed to the rear opening  36  of the frame  32 , and the inside of the sub door  30  formed by the frame  32 , the front panel  33 , and the cooling unit  50  is filled with a foamed material so as to attach the frame  32 , the front panel  33 , and the cooling unit  50  to each other by means of the foamed material. 
         [0073]    Here, in order to reinforce the sub door  30 , a reinforcing member (not shown) may be provided at the inside of the sub door  30 . 
         [0074]    In order to fix the front panel  33  to the edge of the front opening  37  of the frame  32 , the front panel  33  is attached to the edge of the front opening  37  using a double-sided adhesive tape  62 . Further, in order to fix the cooling unit  50  to the rear opening  36  of the frame  32 , the edge of the cooling unit  50  is attached to the edge of the rear opening  36  using a double-sided adhesive tape  61 . 
         [0075]    Here, in addition to the above double-sided adhesive tapes  61  and  62 , various adhesive agents may be used to attach the front panel  33  and the cooling unit  50  to the frame  32 . 
         [0076]    Next, an opening and closing operation of the sub door of the refrigerator in accordance with this embodiment will be described with reference to  FIGS. 3 and 4 . 
         [0077]    In the refrigerator in accordance with this embodiment, the connection member  40  maintains a state of completely closing the second stepped plane  51   b  under the condition that the sub door  30  is closed. Then, when the sub door  30  is opened, the sub door  30  is rotated downwardly using the hinge protrusions  31   a  as a rotary axis. Here, the connection member  40  is rotated using the rotating protrusions  43  as a rotary axis in connection with the rotation of the sub door  30 . 
         [0078]    Since the center of rotation of the sub door  30  differs from the center of rotation of the connection member  40 , when the sub door  30  is opened, the connection member  40  is rotated in connection with the rotation of the sub door  30  and thus performs a sliding movement in a direction of exposing the second stepped plane  51   b.    
         [0079]    Thereafter, when the sub door  30  continues to be rotated, the rear surface of the sub door  30  is located at a position higher than a lower surface  21   b  of the opening  21 . At this time, the connection member  40  is rotated at an angle of about 90 degrees about the rotating protrusions  43 , and is located above the lower surface  21   b  of the opening  21 , thereby preventing a height difference between the sub door  30  and the opening  21 . 
         [0080]    Further, when the sub door  30  is closed, the connection member  40  is rotated in connection with the upward rotation of the sub door  30  and thus performs a sliding movement in a direction of closing the second stepped plane  51   b.  Thereby, as shown in  FIG. 3 , the sub door  30  closes the opening  21  under the condition that the connection member  40  closes the second stepped plane  51   b.    
         [0081]      FIG. 6  is a perspective view illustrating a schematic configuration of a refrigerator in accordance with another embodiment. 
         [0082]    The embodiment of the present invention, as shown in  FIGS. 1 to 5 , illustrates a stand type kimchi refrigerator. On the other hand, the embodiment shown in  FIG. 6  illustrates a side-by-side refrigerator in which a main body  100  is horizontally divided into storage chambers such that one storage chamber is used as a freezing chamber  110  and the other storage chamber is used as a refrigerating chamber  120 . As shown in  FIG. 6 , the side-by-side refrigerator may also employ a sub door  130  in accordance with the embodiment. 
         [0083]    As is apparent from the above description, in a refrigerator having a sub door and a manufacturing method of the sub door in accordance with one embodiment, a cooling unit provided on the sub door transmits cool air of the cooling unit to a stored article put on the rear surface of the sub door, when the sub door is opened. 
         [0084]    Further, the cooling unit lowers the temperature of an opening of a main door which is relatively high, when the sub door is closed, thereby achieving relatively uniform temperature distribution in a storage chamber and thus improving storage performance of the refrigerator. 
         [0085]    Although a few embodiments have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.