Patent Publication Number: US-2013248523-A1

Title: Microwave oven

Description:
FIELD OF TECHNOLOGY 
     The present invention relates to a microwave oven, and more particularly, to a microwave oven in which electronic parts are disposed in a space formed at a rear side of a cavity so as to be smoothly cooled down by one cooling fan. 
     BACKGROUND 
     In general, a microwave oven is a device for cooking food through intermolecular frictional heat generated by disturbing the molecular arrangement of the food using a high frequency of about 2, 450 MHz as a heating source. 
     Such a microwave oven may be mainly divided into a type having a single magnetron and a type having a plurality of magnetrons. 
     The microwave oven having a single magnetron may be used as a microwave oven for home use which is used at a low frequency, and the large-sized microwave oven having a plurality of magnetrons may be used as a microwave oven for business use which is used at a high frequency. 
     The above-described configuration is a related art for helping an understanding of the present invention, and does not mean a related art which is widely known in the technical field to which the present invention pertains. 
     SUMMARY 
     Technical Problem 
     Since the conventional large-sized microwave oven includes a plurality of electronic parts which are spread here and there, the microwave oven has a complex structure for cooling the electronic parts. Furthermore, since the conventional microwave oven includes a plurality of cooling fans to obtain sufficient cooling efficiency, the structure becomes complex, and the manufacturing cost increases. 
     Therefore, there is a demand for a structure capable of solving the problems. 
     The present invention is conceived to solve such problems of the related art, and an aspect of the invention is to provide a microwave oven in which electronic parts are disposed in a space formed at a rear side of a cavity so as to be smoothly cooled down by one cooling fan. 
     Technical Solution 
     According to an aspect of the invention, a microwave oven includes: a cabinet forming the exterior of the microwave oven; a base plate coupled to the cabinet and forming a bottom surface of the microwave oven; a rear plate coupled to the cabinet and forming a rear surface of the microwave oven; a cavity installed on the base plate so as to be spaced from the rear plate, thereby forming a space at a rear side of the base plate; a first high-voltage transformer positioned in the space, and installed in one side of the base plate; a second high-voltage transformer positioned in the space, and installed in the center of the base plate; a first magnetron positioned in the space and disposed in the opposite side of the first high-voltage transformer; a second magnetron positioned in the space and disposed over the first magnetron; a fan assembly positioned in the space and disposed over the first transformer; a fan housing covering the fan assembly and having an air introduction portion formed to face the first high-voltage transformer; and an air guide tube connected to the fan housing, and guiding an air flow generated by operation of the fan assembly to the first and second magnetrons. 
     The base plate may include air suction holes formed at a front surface thereof, through which air is introduced. 
     The external air may be introduced through the air suction holes by the operation of the fan assembly, and then introduced to the fan housing through the air introduction portion while cooling down the first and second high-voltage transformers. 
     The cavity may include: a side plate formed in a U-shape to form both side surfaces and a rear surface of the cavity and spaced from the rear plate; a top plate coupled to the top of the side plate, and protruded rearward from the side plate so as to be coupled to the rear plate; and a bottom plate coupled to the bottom of the side plate, and protruded rearward from the side plate so as to be coupled to the rear plate. 
     The top plate may be coupled to the second magnetron, and the bottom plate may be coupled to the first magnetron. 
     The bottom plate may have a groove portion formed at an edge thereof so as not to interfere with the first and second high-voltage transformers. 
     The air guide tube may be positioned in the space and has one side connected to the fan housing and the other side divided into two portions, a first divided portion may be bent downward toward the first magnetron, and a second divided portion may be bent upward toward the second magnetron. 
     The first divided portion may be coupled to the first magnetron between the second high-voltage transformer and the first magnetron, and the second divided portion may be coupled to the second magnetron between the second magnetron and the fan assembly. 
     The rear plate may have a first discharge hole through which air having cooled down the first magnetron is discharged. 
     The rear plate may have a second discharge hole through which air having cooled down the second magnetron is discharged. 
     Advantageous Effects 
     According to the embodiment of the invention, since various electronic parts may be cooled down by one fan assembly, the size of the microwave oven may be reduced, and the number of parts may be simplified. 
     Furthermore, since the plurality of high-voltage transformers and magnetrons may be cooled down by one fan assembly, the cooling structure may be simplified. 
     Furthermore, the manufacturing cost may be simplified by the reduction in the number of parts and the simplification of the cooling structure. 
    
    
     
       BRIEF DESCRIPTION 
       The above and other aspects, features and advantages of the invention will become apparent from the following detailed description in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a rear perspective view of a microwave oven in accordance with an embodiment of the present invention; 
         FIG. 2  is a rear perspective view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which a rear plate is removed; 
         FIG. 3  is a rear perspective view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which a cabinet and the rear plate are removed; 
         FIG. 4  is a rear view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which the cabinet and the rear plate are removed; 
         FIG. 5  is a side view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which the cabinet is removed; 
         FIG. 6  is a front view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which the cabinet is removed; 
         FIG. 7  is a rear view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which a fan housing is removed from  FIG. 4 ; 
         FIG. 8  is a perspective view of a bottom plate of the microwave oven in accordance with the embodiment of the present invention; and 
         FIG. 9  is a plan view of the bottom plate of the microwave oven in accordance with the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the invention will hereinafter be described in detail with reference to the accompanying drawings. It should be noted that the drawings are not to precise scale and may be exaggerated in thickness of lines or sizes of components for descriptive convenience and clarity only. Furthermore, the terms as used herein are defined by taking functions of the invention into account and can be changed according to the custom or intention of users or operators. Therefore, definition of the terms should be made according to the overall disclosures set forth herein. 
       FIG. 1  is a rear perspective view of a microwave oven in accordance with an embodiment of the present invention.  FIG. 2  is a rear perspective view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which a rear plate is removed.  FIG. 3  is a rear perspective view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which a cabinet and the rear plate are removed.  FIG. 4  is a rear view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which the cabinet and the rear plate are removed.  FIG. 5  is a side view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which the cabinet is removed.  FIG. 6  is a front view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which the cabinet is removed.  FIG. 7  is a rear view of the microwave oven in accordance with the embodiment of the present invention, illustrating a state in which a fan housing is removed from  FIG. 4 .  FIG. 8  is a perspective view of a bottom plate of the microwave oven in accordance with the embodiment of the present invention.  FIG. 9  is a plan view of the bottom plate of the microwave oven in accordance with the embodiment of the present invention. 
     Referring to  FIGS. 1 to 3 , the microwave oven in accordance with the embodiment of the present invention includes a cabinet  10 , a base plate  20 , a rear plate  30 , a cavity  40 , a first high-voltage transformer  50 , a second high-voltage transformer  51 , a first magnetron  60 , a second magnetron  61 , a fan assembly  70 , a fan housing  80 , and an air guide tube  90 . 
     The cabinet  10  is formed in a plate shape bend in a U-shape and forms both side surfaces and the top surface of the exterior of the microwave oven. The base plate  20  is coupled to the bottom of the cabinet  10 , and forms the bottom surface of the exterior of the microwave oven. 
     The base plate  20  includes a plurality of air suction holes  21  formed on the front surface thereof. The air suction holes  21  are formed from one side to the other side of the base plate  20 , and the external air is introduced into the microwave oven through the air suction holes  21 . 
     The rear plate  30  is coupled to the rear end of the cabinet  10 , and forms the rear surface of the exterior of the microwave oven. The front plate  11  is coupled to the front end of the cabinet  10 , and forms the front surface of the exterior of the microwave oven. 
     Referring to  FIGS. 3 to 6 , the cavity  40  forms a cooking room, and is installed on the base plate  20 . The cavity  40  includes a side plate  41 , a top plate  42 , and a bottom plate  43 . 
     The side plate  41  is formed in a plate shape bent in a U-shape, and forms both side surfaces and the rear surface of the cavity  40 . The top plate  42  is coupled to an upper end of the side plate  41  so as to form the top surface, and the bottom plate  43  is coupled to a lower end of the side plate  41  so as to form the bottom surface. 
     The rear surface of the side plate  41  is spaced from the rear plate  30 , thereby forming a space  44  therebetween. That is, the space  44  is defined at the rear side (right side in  FIG. 5 ) of the base plate  20  by the rear surface of the side plate  41  and the rear plate  30 . 
     The top plate  42  is protruded rearward from the side plate  41  and coupled to the rear plate  30 . The bottom plate  43  is protruded rearward from the side plate  41  and coupled to the rear plate  30 . 
     Therefore, the cavity  40  is reliably fixed and coupled to the rear plate  30  by the top plate  42  and the bottom plate  43 , even though the side plate  41  is separated from the rear plate  30 . 
     The first high-voltage transformer  50  is positioned in the space  44 , and installed in one side (right side of  FIG. 3 ) of the base plate  20 . The second high-voltage transformer  51  is positioned in the space  44 , and installed in the center of the base plate  20 . 
     The first and second high-voltage transformers  50  and  51  are arranged in parallel to each other, when seen from the front. Furthermore, the first and second high-voltage transformers  50  and  51  are arranged to overlap each other, when seen from the side. 
     The first magnetron  60  is positioned in the space  44 , and disposed in the opposite side of the first high-voltage transformer  50 . That is, the first magnetron  60  is disposed in the other side (left side of  FIG. 3 ) of the base plate  20 , and coupled to the top surface of the bottom plate  43 . 
     The second magnetron  61  is positioned in the space  44 , and disposed over the first magnetron  60 . The second magnetron  61  is coupled to the bottom surface of the top plate  42 , and disposed in the center when seen from the front. 
     Microwaves generated by the first and second magnetrons  60  and  61  are provided to upper and lower spaces of the cavity  40 , respectively, through a waveguide (not illustrated). 
     Referring to  FIGS. 8 and 9 , the bottom plate  43  has a groove portion  43   a  formed at an edge thereof so as not to interfere with the pair of high-voltage transformers  50  and  51  installed on the base plate  20 . In accordance with the embodiment of the present invention, the bottom plate  43  is formed in an L-shape, and coupled to the rear plate  30  through a portion protruded toward the rear side. Furthermore, the high-voltage transformers  50  and  51  may be easily installed on the base plate  20  through a portion depressed from a corner edge of the bottom plate  43 , that is, the groove portion  43   a.    
     Referring to  FIGS. 3 ,  4 , and  7 , the fan assembly  70  is positioned in the space  44 , and disposed over the first high-voltage transformer  50 . The fan assembly  70  includes a cooling fan  71  and a fan motor  72  to transmit a driving force to the cooling fan  71 . In accordance with the embodiment of the present invention, the fan motor  72  is disposed over the cooling fan  71 . 
     The fan housing  80  covers the fan assembly  70 . Specifically, since the fan housing  80  covers only the cooling fan  71 , the fan motor  72  is disposed in a space separate from the cooling fan  71  by the fan housing  80 . Accordingly, heat generated by the operation of the fan motor  72  is prevented from being contacted with external air introduced to the fan housing  80 . 
     The fan housing  80  has an air introduction portion  81  formed at the bottom thereof. The air introduction portion  81  is formed to face the first high-voltage transformer  50 , and serves as an entrance of air introduced to the fan housing  80  while cooling the first and second high-voltage transformers  50  and  51 . 
     The air guide tube  90  is connected to the fan housing  80 , guides an air flow generated by the operation of the fan assembly  70  to the first and second magnetrons  60  and  61 , and cools down the first and second magnetrons  60  and  61 . 
     The air guide tube  90  is positioned in the space  44 , and has one side connected to a side portion of the fan housing  80  and the other side formed to face the first and second magnetrons  60  and  61 . The other side of the air guide tube  90  is divided into two portions. Between the two portions, a first divided portion  91  is formed to be bent downward toward the first magnetron  60 , and a second divided portion  92  is formed to be bent upward toward the second magnetron  61 . 
     The first divided portion  91  is coupled to the first magnetron  60  between the second high-voltage transformer  51  and the first magnetron  60  so as not to interfere with the second high-voltage transformer  51 . That is, based on  FIG. 4 , the first divided portion  91  is formed to be bent downward past the second high-voltage transformer  51  and coupled to a side portion of the first magnetron  60 . 
     The second divided portion  92  is coupled to a side portion of the second magnetron  61  between the fan motor  72  and the second magnetron  61  such that the length of the second divided portion  92  is minimized. 
     The air introduced from outside by the operation of the fan assembly  80  is introduced to the fan housing  80  through the air introduction portions  81 . Then, the air is guided by the first divided portion  91  and cools down the first magnetron  60 . The air heated while cooling down the first magnetron  60  is guided by a first connection tube  91   a  and discharged to the outside through a first discharge hole  31  formed in the rear plate  30 . 
     That is, when the air having cooled down the first magnetron  60  remains in the microwave oven, the internal temperature of the microwave oven is increased. Therefore, in order to prevent the increase of the internal temperature, the rear plate  30  has the first discharge hole  31  to discharge the air to the outside. Therefore, the first discharge hole  31  is formed at a place corresponding to the installation position of the first magnetron  60 . 
     Furthermore, the air introduced by the operation of the fan assembly  80  is guided by the second divided portion  92  so as to cool down the second magnetron  61 , and then guided by a second connection tube  92   a  so as to be discharged to the outside through a second discharge hole  32  formed in the rear plate  30 . 
     That is, when the air having cooled down the second magnetron  61  remains in the microwave oven, the internal temperature of the microwave oven is increased. Therefore, in order to prevent the internal temperature of the microwave oven, the rear plate  30  has the second discharge hole  32  formed to discharge the air to the outside. Therefore, the second discharge hole  32  is formed at a place corresponding to the installation position of the second magnetron  61 . 
     Hereinafter, referring to the accompanying drawings, the air flow process in the microwave oven in accordance with the embodiment of the present invention will be described. 
     When the operation of the microwave oven is started, the fan motor  72  is driven to rotate the cooling fan  71 . The rotations of the cooling fan  71  generate an air suction force, and the external air is introduced into the microwave oven through the air suction holes  21  formed at the front surface of the base plate  20  by the air suction force. 
     The air is moved to the fan housing  80 , in which the air suction force is generated, through the space formed by the base plate  20  and the bottom plate  43  of the cavity  40 . 
     The first and second high-voltage transformers  50  and  51  are disposed in the space  44  at the rear side of the base plate  20 , and the fan housing  80  is disposed over the first high-voltage transformer  50 . Accordingly, the air is introduced to the fan housing  80  through the first and second high-voltage transformers  50  and  51 . Therefore, the first and second high-voltage transformers  50  and  51  placed on the flow path of the air are automatically cooled by the air. 
     Since the groove portion  43   a  is formed in the bottom plate  43  guiding the air flow and the first and second high-voltage transformers  50  and  51  are disposed at the position corresponding to the groove portion  43   a , the cooling efficiency is improved more than when the first and second high-voltage transformers  50  and  51  are disposed at different positions. 
     The air which is introduced to the fan housing  80  through the air introduction portion  81  while cooling down the first and second high-voltage transformers  50  and  51  is guided by the first and second divided portions  91  and  92  communicating with the fan housing  80 , thereby cooling down the first and second magnetrons  60  and  61 . 
     The air having cooled down the first magnetron  60  is guided by the first connection tube  91   a  and discharged to the outside through the first discharge hole  31 , and the air having cooled down the second magnetron  61  is guided by the second connection tube  92   a  and discharged to the outside through the second discharge hole  32 . 
     Although some embodiments have been provided to illustrate the invention in conjunction with the drawings, it will be apparent to those skilled in the art that the embodiments are given by way of illustration only, and that various modifications and equivalent embodiments can be made without departing from the spirit and scope of the invention. The scope of the invention should be limited only by the accompanying claims.