Abstract:
A nozzle assembly capable of evenly spraying wash water at an inside a washing tub and a dishwasher having the same, the nozzle assembly including a nozzle configured to rotate on a rotating axis thereof, an inside rotor having a shape of a cylinder and configured to rotate according to a rotation of the nozzle while coupled to the rotating axis, and an outside rotor case having a larger radius than a radius of the inside rotor to accommodate the inside rotor therein, and having an opening hole through which the rotating axis passes, and the rotating axis of the nozzle revolves around a circumference of the opening hole.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2012-0002103, filed on Jan. 6, 2012 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND 
       [0002]    1. Field 
         [0003]    Embodiments of the present disclosure relate to a nozzle assembly of a dishwasher, and more particularly, to a nozzle assembly capable of evenly spraying wash water at an inside a washing tub and a dishwasher having the same. 
         [0004]    2. Description of the Related Art 
         [0005]    A dishwasher is configured to spray high-pressure wash water on a dishware to clean the dishware, and goes through a preliminary cleaning, a main cleaning, a rinsing, and a drying stage. In the preliminary cleaning stage, by spraying wash water without the input of a detergent, the residue of dishware is eliminated. In the main cleaning stage, while wash water is sprayed, a detergent is input by a detergent supply apparatus, and thereby the cleaning of the dishware is performed. 
         [0006]    A dishwasher includes a body provided with a washing tub at an inside thereof, a movable basket configured to contain dishware and inside the washing tub. A nozzle assembly provided at upper/lower portions of the basket to spray wash water, and the wash water sprayed from the nozzle assembly cleans dishware. 
         [0007]    A nozzle assembly is configured to spray wash water while rotating at a fixed position, and in a case when the nozzle assembly is disposed as such, a dead zone to which wash water is not reached is present at an inside the washing tub. 
       SUMMARY 
       [0008]    Therefore, it is an aspect to provide a nozzle assembly configured to spray wash water to a throughout inside a washing tub and a dishwasher having the same. 
         [0009]    Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosure. 
         [0010]    In accordance with one aspect, a nozzle assembly includes a nozzle, an inside rotor, and an outside rotor case. The nozzle may be configured to rotate on a rotating axis thereof. The inside rotor may have a shape of a cylinder and configured to rotate according to a rotation of the nozzle while coupled to the rotating axis. The outside rotor case may have a larger radius than a radius of the inside rotor to accommodate the inside rotor therein, and have an opening hole through which the rotating axis passes. The rotating axis of the nozzle may revolve around a circumference of the opening hole. 
         [0011]    The rotating axis of the nozzle, while rotating, may revolve around a center of the outside rotor case. 
         [0012]    The outside rotor case may include a plurality of outside protrusions protrudedly formed in a radial inward direction from the circumference of the opening hole. 
         [0013]    The inside rotor may include a projection protruded from an upper surface of the inside rotor and formed to pass through the opening hole of the outside rotor case. 
         [0014]    The inside rotor may further include a plurality of inside protrusions protrudedly formed in an outer radial direction along a circumference of the projection at a side surface of the projection. 
         [0015]    The number of the plurality of inside protrusions may be less than the number of the plurality of outside protrusions. 
         [0016]    The inside protrusion may be formed in a corresponding shape to an indentation part formed in between the outside protrusions. 
         [0017]    The nozzle may include an outlet port through which wash water is sprayed. 
         [0018]    The outlet port may be provided in a way that a direction of the wash water sprayed from an upper surface of the nozzle is formed in an inclined manner with respect to an upper surface of the nozzle. 
         [0019]    At least one of the nozzle and the inside rotor may be rotated by a reaction against the wash water sprayed from the outlet hole. 
         [0020]    In accordance with another aspect, a nozzle assembly includes a nozzle, a rotor, a rotor case and an eccentric rotation guide. The nozzle may be configured to rotate on a rotating axis thereof. The rotor may be configured to rotate according to a rotation of the nozzle while coupled to the rotating axis. The rotor case may be configured to accommodate the rotor and have an opening hole through which the rotating axis passes. The eccentric rotation guide may be formed in a circular-shape plate and have a rotor coupling hole formed to allow the rotor to be coupled while being positioned at a side away from a center of the eccentric rotation guide. The rotating axis of the nozzle, by the eccentric rotation guide, may revolve along a circumference of the opening hole. 
         [0021]    The rotor may have inside teeth protrudedly formed in an outward radial direction along a circumference of a side surface of the rotor. The rotor case may have outside teeth protrudedly formed along the circumference of the opening hole in an inward radial direction in a corresponding shape to the inside teeth. 
         [0022]    The nozzle may include an outlet port through which wash water is sprayed. 
         [0023]    The outlet port may be provided in a way that a direction of the wash water sprayed from the upper surface of the nozzle is formed in an inclined manner with respect to an upper surface of the nozzle. 
         [0024]    At least one of the nozzle and the rotor is rotated by a reaction against the wash water sprayed from the outlet hole. 
         [0025]    In accordance with another aspect, a dishwasher includes a case, a washing tub, and at least one nozzle assembly. The washing tub may be disposed at an inside the case and accommodating dishware. The at least one nozzle assembly may be configured to spray wash water to an inside the washing tub to clean the dishware at an inside the washing tub. The nozzle assembly may include a nozzle, an inside rotor, and an outside rotor case. The inside rotor may have a shape of a cylinder and configured to rotate according to a rotation of the nozzle while coupled to the rotating axis. The outside rotor case may have a larger radius than a radius of the inside rotor to accommodate the inside rotor therein, and have an opening hole through which the rotating axis passes. The nozzle may be configured to rotate on the rotating axis thereof, and the rotating axis may be configured to revolve around a center of the outside rotor case. 
         [0026]    The outside rotor case may include a plurality of outside protrusions protrudedly formed in an inward radial direction from a circumference of the opening hole. 
         [0027]    The inside rotor may include a projection and a plurality of inside protrusions. The projection may be protruded from an upper surface of the inside rotor and formed in a way to penetrate the opening hole of the outside rotor case. The plurality of inside protrusions may be protrudedly formed in an outward radial direction along a circumference of the projection from a side surface of the projection. 
         [0028]    In accordance with another aspect, a nozzle assembly includes a case, a washing tub, and at least one nozzle assembly. The washing tub may be disposed at an inside the case and accommodate dishware. The at least one nozzle assembly may be red to spray wash water to an inside the washing tub to clean the dishware at an inside the washing tub. The nozzle assembly may include a nozzle, a rotor, a rotor case and an eccentric rotation guide. The nozzle may be configured to rotate on a rotating axis thereof. The rotor may be configured to rotate according to a rotation of the nozzle while coupled to the rotating axis. The rotor case may be configured to accommodate the rotor and have an opening hole through which the rotating axis passes. The eccentric rotation guide may be formed in a circular-shape plate and have a rotor coupling hole formed in a way that the rotor is coupled while being positioned at a side away from a center of the eccentric rotation guide. 
         [0029]    As a rotating axis of a nozzle revolve while rotating along with the rotation of the nozzle, wash water is reached to a corner of a washing tub. 
         [0030]    By the driving force alone caused by the reaction of the wash water sprayed from a nozzle, the rotating and the revolving of the rotating axis are realized, and thus, a separate driving force is not needed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]    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: 
           [0032]      FIG. 1  is a drawing illustrating a structure of a dishwasher in accordance with one embodiment. 
           [0033]      FIG. 2  is a drawing illustrating a nozzle assembly in accordance with one embodiment of the present disclosure. 
           [0034]      FIG. 3  is a perspective view of the structure of the nozzle assembly on  FIG. 2 . 
           [0035]      FIG. 4  is a cross-sectional view of the nozzle assembly on  FIG. 2 . 
           [0036]      FIG. 5  is a drawing illustrating an inside rotor and an outside rotor case of the nozzle assembly on  FIG. 2 . 
           [0037]      FIG. 6  is a drawing illustrating a rotation of the nozzle assembly on  FIG. 2 . 
           [0038]      FIG. 7  is a drawing illustrating a structure of a nozzle assembly in accordance with one embodiment. 
           [0039]      FIG. 8  is a cross-sectional view of the nozzle assembly on  FIG. 7 . 
           [0040]      FIG. 9  is a drawing illustrating an inside rotor and an outside rotor case of the nozzle assembly on  FIG. 7 . 
           [0041]      FIG. 10  is a drawing illustrating a structure of a nozzle assembly in accordance with one embodiment. 
           [0042]      FIG. 11  is a cross-sectional view of the nozzle assembly on  FIG. 10 . 
           [0043]      FIG. 12  is a drawing illustrating a rotor and a rotor case of the nozzle assembly on  FIG. 10 . 
       
    
    
     DETAILED DESCRIPTION 
       [0044]    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. 
         [0045]      FIG. 1  is a drawing illustrating a structure of a dishwasher in accordance with one embodiment. 
         [0046]    As illustrated on  FIG. 1 , a dishwasher  1  includes a body  10  forming an exterior thereof, a washing tub  20  provided at an inside the body  10  and forming a washing space of dishware, and a sump  30  provided at a lower portion of the washing tub  20  and at which wash water is stored. 
         [0047]    A front surface of the body  10  is open is open in the front to allow dishware to be stored or withdrawn from wash tub  20 . The front surface of the body  10  is provided with a door  11 , a lower portion of which is hingedly coupled to the front surface of the body  10  to open/close the washing tub  20 . 
         [0048]    At an inside the washing tub  20 , a pair of dishware baskets  51 , each is provided with an accommodating part having a upper side thereof open for dishware to be stored, are installed at an upper portion and a lower portion of the washing tub  20  in a way to move forward/backward. The dishware basket  51 , by at least one rack  56  configured to slidably support the dishware basket  51 , is put into/taken out from the washing tub  20  through the front of the body  10 . 
         [0049]    The dishware basket  51  is formed by wires formed in, for example, a grid pattern, such that the dishware stored at an inside thereof is exposed to an outside and cleaned. 
         [0050]    At least one nozzle assembly  100  is mounted and rotatively installed at an upper side, a lower side, and a central side of the two dishware baskets  51  at an inside the washing tub  20 , and configured to spray water for the dishware stored in the dishware baskets  51  is cleaned. At least the one nozzle assembly  100  may include an upper portion nozzle  103 , a central nozzle  102 , and a lower portion nozzle  101 . On the drawing, the total of three nozzle assemblies  100  are illustrated, but having more or less than three nozzle assemblies  100  may be included in an embodiment of the present disclosure. 
         [0051]    A heater  35  to heat wash water and a heater installing groove  36  may be formed at the washing tub  20 . The heater installing groove  36  is provided at a bottom of the washing tub  20 , and the heater  35  is installed at the heater installing groove  36 . 
         [0052]    The sump  30  is provided at a center of a bottom of the washing tub  20  to collect wash water and pump the collected wash water. The sump  30  includes a cleaning pump  31  configured to pump at high pressure, and a pump motor  32  to drive the cleaning pump  31 . 
         [0053]    The cleaning pump  31  is configured to pump wash water to the upper portion nozzle  103  through a first supply pipe  41 , and through a second supply pipe  42  branching from the first supply pipe  41 , the cleaning pump  31  pumps wash water to the central nozzle  102 . Through a third supply pipe  43 , wash water is pumped to the lower portion nozzle  101 . 
         [0054]    The sump  30  may include a turbidity sensor (not shown) to detect the pollution level of wash water. A control unit (not shown) of the dishwasher  1 , by using the turbidity sensor (not shown), detects the pollution level of wash water, and may control the number of frequencies in processing a cleaning cycle and a rinsing cycle. That is, in a case when pollution level is high, a cleaning or rinsing cycle is increased, and in a case when pollution level is low, a cleaning or rinsing cycle may be decreased. 
         [0055]      FIG. 2  is a drawing illustrating a nozzle assembly in accordance with one embodiment of the present disclosure, and  FIG. 3  is a perspective view of the structure of the nozzle assembly on  FIG. 2 . 
         [0056]    As illustrated on  FIGS. 2 to 3 , the nozzle assembly  100  includes a nozzle  110 , an inside rotor  120  coupled to the nozzle  110  and rotates along with the nozzle  110 , and an outside rotor case  130  accommodating the inside rotor  120  and connected to a supply pipe  40 . 
         [0057]    An upper surface  111  of the nozzle  110  is provided with at least one outlet port  115  ( FIG. 6 ), which is protruded from the upper surface  111 , formed thereto 
         [0058]    A rotating axis  112  is formed while protruded from a central portion of the nozzle  110  toward a lower side. Along the circumference of the side surface of the rotating axis  112 , screw threads are formed for the coupling with the inside rotor  120 . 
         [0059]    A projection  122  is protrudedly formed from an upper surface  121  of the inside rotor  120  toward an upper side. A plurality of inside protrusions  123 , while is protruded along the circumference of the side surface of the projection  122  in a radial direction toward an outer side, is formed while each of the plurality of inside protrusion  123  is provided with a gear shape. 
         [0060]    As a central portion of the projection  122  is open, a nozzle coupling hole  124  is formed such that the rotating axis  112  of the nozzle  110  of inside rotor  120  is coupled to the nozzle coupling hole  124 . An inside surface  125  of the projection  122  is provided with screw threads configured to be coupled to the screw threads formed at the circumference of the rotating axis  112 , so that the nozzle  100  is coupled the inside rotor  120 . 
         [0061]    The outside rotor case  130  is formed as an upper portion cover  140  and a lower portion cover  150  are coupled to each other. The lower portion cover  150  includes a lower portion cover bottom  151  and a lower portion cover side surface  152  protruding from the lower portion cover bottom  151  and forming a rotor accommodation space  153 . Along the circumference of the lower portion cover side surface  152 , screw threads are formed. A supply pipe coupling part  154  is formed by extending toward a lower side from the lower portion cover bottom  151 . As the supply pipe coupling part  154  is inserted into the supply pipe  40 , the supply pipe  40  and the outside rotor case  130  are connected to each other. 
         [0062]    The upper portion cover  140  is provided with an open upper portion thereof to form an opening hole  141 , and the opening hole  141  is surrounded by an upper portion cover side surface  142 . At an inner side surface of the upper portion cover side surface  142 , screw threads is formed to be coupled to the screw threads of the lower portion cover side surface  152 . 
         [0063]    A plurality of outside protrusions  143  is formed while being bent in an inward radial direction from an upper portion of the upper portion cover side surface  142 . The plurality of outside protrusions as a whole is formed in a shape of a gear. Indentation parts  144 , which are shown as indentations relative to the outside protrusions  143  protrudedly formed, are formed in between the outside protrusions  143 . 
         [0064]    The projection  122  of the inside rotor  120  is disposed in a way to penetrate the opening hole  141  of the outside rotor case  130 . Thus, the inside protrusions  123  of the inside rotor  120  are disposed in between the indentation parts  144  of the outside rotor case  130 . Furthermore, the rotating axis  112  of the nozzle  110 , which is coupled to the nozzle coupling hole  124  of the projection  122 , is disposed to penetrate the opening hole  141 . 
         [0065]    The number of the inside protrusions  123  of the inside rotor  120  is one less than the number of the indentation parts  144  of the outside rotor case  130 . The forming of the inside rotor  120  and the outside rotor case  130  as such is referred to as a gerotor. 
         [0066]    In the embodiment, for example, the total of six of the inside protrusions  123  and the total of seven of the outside protrusions  143  are formed, but as long as the number of the inside protrusions  123  of the inside rotor  120  is one less than the number of the indentation parts  144  of the outside rotor case  130 , the setting of the number of the inside protrusions  123  and the outside protrusions  143  is not set. 
         [0067]    By controlling the number of the inside protrusions  123  and the outside protrusions  143 , the revolving path of the inside rotor  120  that revolves around the opening hole  141  of the outside rotor case  130  may be variably changed. 
         [0068]      FIG. 4  is a cross-sectional view of the nozzle assembly on  FIG. 2 , and  FIG. 5  is a drawing illustrating an inside rotor and an outside rotor case of the nozzle assembly on  FIG. 2 . 
         [0069]    As illustrated on  FIGS. 4 to 5 , the inside rotor  120  rotates, as the inside protrusions are positioned at the indentation parts  144  of the outside rotor case  130 . Thus, the rotating axis  112  of the nozzle  110  and the center of a rotation C 100  of the inside rotor  120 , as well as the center of a rotation C 130  of the outside rotor case  130  are present on different lines from one another while not forming a straight line. That is, the nozzle  110  and the inside rotor  120  are disposed in a way that the center of the rotation C 110  of the rotating axis  112  is disposed at a position spaced away from the center of the rotation C 130  of the outside rotor case  130 . 
         [0070]    If the inside rotor  120  and the nozzle  110  are disposed as such, the rotating axis  112  as well rotates along the circumference of the opening hole  141  of the outside rotor case  130  by the rotation of the nozzle  110 , and thus, the rotating axis  112  is simultaneously rotated and revolves. 
         [0071]    By the rotation of the rotating axis  112  as such, the moving range of the nozzle  110  is also widened, and as the movement of the nozzle  110  is larger, wash water may be sprayed to each and every corner of an inside the washing tub  20  ( FIG. 1 ). 
         [0072]      FIG. 6  is a drawing illustrating a rotation of the nozzle assembly on  FIG. 2 . 
         [0073]    As illustrated on  FIG. 6 , a plurality of outlet ports  115  is formed at the upper surface  111  of the nozzle  110 . The outlet ports  115  includes a third outlet port  116  formed to spray wash water in a perpendicular direction to the upper surface  111 , a first outlet port  118  formed to face a first direction F from the upper surface  111 , such that wash water is sprayed while inclined by a predetermined angle with respect to a perpendicular direction from the upper surface  111  toward the first direction F, and a second outlet port  117  formed to face a second direction B from the upper surface  111 , such that wash water is sprayed while inclined by a predetermined angle with respect to a perpendicular direction from the upper surface  111  toward the second direction B. 
         [0074]    In accordance with the embodiment, by having one side of the nozzle  110  as a reference, the total of four units of the second outlet port  117  facing the second direction B is formed, and the total of two units of the first outlet port  118  facing the first direction F is formed. Thus, the number of the second outlet port  117  is greater than the number of the first outlet port  118 . By the sum of the forces caused by the reaction of the wash water sprayed from the outlet ports  115 , the nozzle  110  is rotated toward the first direction F. 
         [0075]    The number of each of the outlet ports  115  formed differently from the illustration on the drawing may be included in the aspect of the present disclosure. Furthermore, the rotating of the nozzle  110  rotating toward the second direction B as more number of the first outlet port  118  is formed may also be included in the aspect of the present disclosure. 
         [0076]    As the nozzle  110  is rotated as such, accordingly, the inside rotor  120  also is rotated. 
         [0077]      FIG. 7  is a drawing illustrating a structure of a nozzle assembly in accordance with another embodiment of the present disclosure. 
         [0078]    As illustrated on  FIG. 7 , a nozzle assembly  200  includes a nozzle  210 , an inside rotor  220  coupled to the nozzle  210  and rotates along with the nozzle  210 , and an outside rotor case  230  accommodating the inside rotor  220  and connected to the supply pipe  40 . The outside rotor case  230  is not rotated, but is configured to limit the rotation path of the inside rotor  220  while performing a role as a case to accommodate the inside rotor  220 . 
         [0079]    A rotating axis  212  is formed while protruded from a central portion of the nozzle  210  toward a lower side. Along the circumference of the side surface of the rotating axis  212 , screw threads are formed for the coupling with the inside rotor  220 . 
         [0080]    A projection  222  is protrudedly formed from an upper surface  221  of the inside rotor  220  toward an upper side. A central portion of the projection  222  is open, and a nozzle coupling hole  224  is formed. An inside surface of the projection  222  is provided with screw threads formed coupled to the screw threads formed at the circumference of the rotating axis  212  such that the nozzle  200  is coupled to the inside rotor  220 . As the rotating axis  212  is inserted into the nozzle coupling hole  224 , the nozzle  210  is coupled to the inside rotor  220  by the screw threads of the rotating axis  212  and the projection  212 . 
         [0081]    The outside rotor case  230  is formed as an upper portion cover  240  and a lower portion cover  250  are coupled to each other. The lower portion cover  250  includes a lower portion cover bottom  251  and a lower portion cover side surface  252  protruding from the lower portion cover bottom  251  and forming a rotor accommodation space  253 . Along the circumference of the lower portion cover side surface  252 , screw threads are formed. A supply pipe coupling part  254  is formed while extended toward a lower side from the lower portion cover bottom  251 . As the supply pipe coupling part  254  is inserted into the supply pipe  40 , the supply pipe  40  and the outside rotor case  230  are connected to each other. 
         [0082]    The upper portion cover  240  includes an upper portion cover side surface  242  forming a side surface circumference of the upper portion cover  240 , and an upper portion cover upper surface  243  formed while bent from an upper portion of the upper portion cover side surface  242  toward an inner side. The central portion of the upper portion cover upper surface  243  is open, and forms an opening hole  241 . 
         [0083]    The projection  222  of the inside rotor  220  and the rotating axis  212  coupled to the nozzle coupling hole  224  of the projection  222  are disposed to penetrate the opening hole  241  of the outside rotor case  230 . Thus, the projection  222  may be freely moved at an inside the opening hole  241  of the outside rotor case  230 . 
         [0084]    By the rotation of the nozzle  210 , the inside rotor  220  also rotates, and at the same time, freely moves at an inside the opening hole  241 . Accordingly, the nozzle  210  is not rotated at a fixed position, but also revolves around. However, as the projection  222  of the inside rotor  220  is engaged at an inside the opening hole  241 , the movement of the inside rotor  220  is limited by the shape and size of the opening hole  241 . 
         [0085]      FIG. 8  is a cross-sectional view of the nozzle assembly on  FIG. 7 , and  FIG. 9  is a drawing illustrating an inside rotor and an outside rotor case of the nozzle assembly on  FIG. 7 . 
         [0086]    As illustrated on  FIGS. 8 to 9 , the center of the rotation C 210  of the nozzle  210  and the center of the rotation C 230  of the outside rotor case  230  may be present on different lines from one another, while not forming a straight line, as the inside rotor  220  is freely moved at an inside the outside rotor case  230  and the opening hole  241 . And, depending on a circumstance, the center of the rotation C 210  of the nozzle  210  and the center of the outside rotor case  230  may be placed on a straight line. With this possible irregular revolution of the nozzle  210  around the center of the outside rotor case  230 , washing water spray pattern is varied. 
         [0087]    As the nozzle  210  may be able to move, while rotating on the center of rotation C 210  at an inside the opening hole  241  according to the movement of the inside rotor  220 , wash water may be able to be sprayed to each and every corner of the inside the washing tub  20  ( FIG. 1 ). 
         [0088]      FIG. 10  is a drawing illustrating a structure of a nozzle assembly in accordance with another embodiment of the present disclosure. 
         [0089]    As illustrated on  FIG. 10 , a nozzle assembly  300  includes a nozzle  310 , a rotor  320  configured to rotate along with the nozzle  310  while coupled to the nozzle  310 , an eccentric rotation guide  330  coupled to the rotor  320  and configured for the rotor  320  to eccentrically rotate, and a rotor case  340  accommodating the rotor  320  and the eccentric rotation guide  330 . 
         [0090]    An upper surface  311  of the nozzle  310  is provided with at least one outlet port  315 . The description of the shape of the outlet port  315  is replaced with the description provided in the above embodiment. 
         [0091]    A rotating axis  312  is formed while protruded from a central portion of the nozzle  310  toward a lower side. Along the circumference of the side surface of the rotating axis  312 , screw threads are formed for the coupling with the rotor  320 . 
         [0092]    The rotor  320  includes a bottom panel  322 , and a projection  321  protrudedly formed from the bottom panel  322  toward an upper side. 
         [0093]    A central portion of the rotor  320  is open to form a nozzle coupling hole  324  such that the rotating axis  312  of the nozzle  310  is coupled to the rotor  320 . An inside surface of the projection  321  is provided with screw threads, which correspond to the screw threads formed at the circumference of the rotating axis  312 , formed thereto. 
         [0094]    Inside teeth  323  are protrudedly formed in a radial direction along the circumference of the outer surface of the projection  321  toward an outside. 
         [0095]    The rotor  320  is rotatably coupled to the eccentric rotation guide  330 . The eccentric rotation guide  330  includes a circular-shape plate  332 , and a rotor coupling hole  331  formed as some portion of the plate  332  is open. The rotor coupling hole  331  is formed while being eccentrically placed at a position at a side away from the center of the plate  332 . The rotor  320  is rotatably coupled to the rotor coupling hole  331  while the projection  321  of the rotor  320  penetrates the rotor coupling hole  331 . 
         [0096]    As the rotor coupling hole  331  is coupled while eccentrically placed from the center of the plate  330  to an edge of the plate  332 , in a case when the rotor  320  is rotated by the rotation of the nozzle  310 , the rotor  320  is not rotated at a fixed position, but revolves around the center of the plate  332 . 
         [0097]    A rotor case  340  is formed as an upper portion case  350  and a lower portion case  360  are coupled to each other. The lower case  360  has a bottom  361  and a side surface  362  protruding from the bottom  361  and forming a rotor accommodation space  366 . For example, a circular rib  365  may be provided on the bottom  361  to support the plate  332  so as to reduce a friction between the bottom  361  and the plate  332  while the eccentric rotation guide rotates within the rotor case  340 . The rib  365  may have different shapes as long as the rib  365  can support the plate  332  while rotating. The lower portion case  360  is extended toward a lower side from a bottom  361  to form a supply pipe coupling unit  364 . As the supply pipe coupling unit  364  is inserted into the supply pipe  40 , the supply pipe  40  and the rotor case  40  are connected to each other. 
         [0098]    The upper portion case  350  includes an opening hole  351  formed while having the upper portion thereof open, and an upper portion case side surface  353  surrounding the opening hole  351 . Outside teeth  352 , which correspond to the inside teeth  323  of the rotor  320 , are formed at an inner side surface of the upper portion case side surface  353 . The inside teeth  323  and the outside teeth  352  are formed to be interlocked to each other, such that the rotor  320  revolve along the opening hole  351  of the upper portion case  350 . 
         [0099]      FIG. 11  is a cross-sectional view of the nozzle assembly on  FIG. 10 , and  FIG. 12  is a drawing illustrating a rotor and a rotor case of the nozzle assembly on  FIG. 10 . 
         [0100]    As illustrated on  FIGS. 11 to 12 , the center of the rotation C 310  of the nozzle  310  and the eccentric rotation guide  330 , as well as the center C 340  of the rotor case  340  are not present on a straight line, but are present on different lines from one another. Thus, the nozzle  310  is rotated on the center of rotation C 310 , and at the same time, the nozzle  320  and the rotor  320  revolve around the center of the eccentric rotation guide  330  and the center C 340  of the rotor case  340 . According to this structure, irregular revolution of the rotor  320  around the center C 340  of the rotor case  340  can be prevented by the eccentric rotation guide. It is apparent to apply the eccentric rotation guide to previously described embodiments as shown in  FIGS. 3 and 7  in order to make sure a rotation and a regular revolution of the nozzle of the dishwasher around the center of the supply pipe  40 . 
         [0101]    Through the movement as such, wash water may be sprayed to each and every corner of an inside the washing tub  20  ( FIG. 1 ). 
         [0102]    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 disclosure, the scope of which is defined in the claims and their equivalents.