Patent Publication Number: US-2023157514-A1

Title: Dishwasher

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation application, under 35 U.S.C. §111(a), of international application No. PCT/KR2022/012950, filed on Aug. 30, 2022, which claims priority to Korean Patent Application No. 10-2021-0164530, filed on Nov. 25, 2021, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety 
     BACKGROUND 
     1. Field 
     The disclosure relates to a dishwasher including a spray device including an improved structure. 
     2. Description of Related Art 
     In general, a dishwasher is a device for washing and drying dishes by spraying washing water at a high pressure. The dishwasher is operated in such a way that washing water is sprayed at high pressure into a washing chamber in which dishes are stored, and the sprayed washing water comes into contact with the dishes to wash foreign substances such as food waste on a surface of the dishes. 
     The dishwasher may include a main body, a tub arranged inside the main body, a sump in which washing water is stored, a storage container arranged inside the tub to accommodate dishes, and a spray device configured to spray the washing water into the storage container. 
     For example, the spray device of the dishwasher may be provided with a plurality of rotors. In this case, due to the structure in which the plurality of rotors is coupled, foreign substances such as food waste may be caught between the rotors, and the rotors may be shaken during rotation because a fixation thereof is not easy. In addition, a flow loss may occur while the washing water pumped from the sump is introduced into the plurality of rotors. 
     SUMMARY 
     Therefore, it is an aspect of the disclosure to provide a dishwasher including a spray device including an improved structure. 
     Additional aspects of the disclosure 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. 
     In accordance with an aspect of the disclosure a dishwasher includes a tub, a basket inside the tub to accommodate an object to wash, a spray device configured to spray washing water to wash the object accommodated in the basket, and a sump configured to supply the washing water stored therein to the spray device. The spray device includes a first spray rotor including a first spray arm configured to spray the washing water and a shaft integrally formed with the first spray arm to guide the washing water supplied from the sump, to the first spray arm therethrough, a second spray rotor rotatably coupled to the shaft, the second spray rotor including a second spray arm configured to spray washing water branched from the washing water which is guided to the first spray arm through the shaft, and a shaft hole formed in the second spray arm to allow the shaft to pass therethrough, and a communication hole formed in the shaft to allow the shaft to communicate with the second spray arm so that a portion of washing water, which is guided to the first spray arm, to flow into the second spray arm. 
     The dishwasher may further include a holder coupled to an outer peripheral surface of the shaft to support the second spray rotor. 
     The second spray rotor may further include a rotation guide formed in the shaft hole to reduce friction with the shaft, and the rotation guide comprising a plurality of guide protrusions protruding toward a center of the shaft hole and to be in contact with an outer peripheral surface of the shaft when the shaft is inserted into the shaft hole, the plurality of guide protrusions being spaced apart from each other along a peripheral direction of the shaft hole. 
     The second spray arm may further include an upper body and a lower body coupled to a lower side of the upper body to form a flow path through which the washing water flows. The shaft hole may further include a first shaft hole formed in the upper body and a second shaft hole formed in the lower body. The rotation guide may further include a first rotation guide formed in the first shaft hole and a second rotation guide formed in the second shaft hole and vertically spaced apart from the first rotation guide. 
     The dishwasher may further include a supporting tube provided to support the outer peripheral surface of the shaft and formed such that one end of the supporting tube is connected to the holder and the other end of the supporting tube is connected to the sump. 
     The shaft and the holder may be inserted into the supporting tube. The shaft may include a first support protrusion protruding to be in contact with an inner peripheral surface of the supporting tube. The holder may include a second support protrusion protruding to be in contact with the inner peripheral surface of the supporting tube and vertically spaced apart from the first support protrusion. 
     The first spray rotor may further include at least one first sealing protrusion protruding toward the second spray arm of the second spray rotor and at least one first sealing groove adjacent to the at least one first sealing protrusion. The second spray rotor may further include at least one second sealing protrusion protruding toward the first spray arm of the first spray rotor and at least one second sealing groove adjacent to the at least one second sealing protrusion. When the first spray rotor is coupled to the second spray rotor, the at least one first sealing protrusion may be inserted into the at least one second sealing groove corresponding to the at least one first sealing protrusion. The second spray rotor may further include at least one third sealing protrusion protruding toward the holder. The holder may further include at least one fourth sealing protrusion protruding toward the second spray rotor and alternately arranged with the at least one third sealing protrusion with respect to the radial direction. 
     Each of the second sealing protrusion and the third sealing protrusion of the second spray rotor may be a ring shaped. An outermost diameter of the second sealing protrusion may be greater than an outermost diameter of the third sealing protrusion, and a protruding length of the second sealing protrusion may be greater than a protruding length of the third sealing protrusion. 
     The first spray rotor may further include a curved member formed to be curved between the shaft and the first spray arm to reduce a pressure loss of the washing water guided to the first spray arm through the shaft. 
     The holder may further include a hook protruding toward the shaft, and the shaft may further include a hook groove to be engaged with the hook. 
     The supporting tube may further include a flange bent outward in a radial direction from the one end of the supporting tube, and the holder may further include a flange hook protruding radially inward toward the flange to be engaged with the flange of the supporting tube. 
     The first spray rotor and the second spray rotor may be formed of a material different from a material of the holder to reduce friction with the holder. 
     The shaft may include a truncated cone shape in which a diameter of the shaft is reduced as a distance from the first spray arm is increased. 
     Each of the first spray arm and the second spray arm may extend in a direction perpendicular to an extension direction of the shaft, and an extension length of the first spray arm may be greater than an extension length of the second spray arm. The first spray arm may include a plurality of first nozzles along a longitudinal direction of the first spray arm, and the second spray arm may include a plurality of second nozzles along a longitudinal direction of the second spray arm. A number of the plurality of first nozzles may be greater than a number of the plurality of second nozzles. 
     The at least one first sealing protrusion and the at least one first sealing groove may be alternatively formed in a radial direction, and the at least one second sealing protrusion and the at least one second sealing groove may be alternatively formed in the radial direction. 
     In accordance with another aspect of the disclosure a dishwasher includes a tub forming a washing chamber, a first spray arm to be rotated in a first direction to spray washing water to the washing chamber, a shaft integrally formed with the first spray arm to extend downwardly from the first spray arm and to guide the washing water to the first spray arm, a second spray arm on a lower side of the first spray arm and to be rotated in a second direction to spray the washing water to the washing chamber, a shaft hole formed in the second spray arm and to allow the shaft to penetrate through the second spray arm so that the second spray arm is rotatably coupled to an outer peripheral surface of the shaft, a pair of sealing members between the first spray arm and the second spray arm to prevent a leakage of the washing water, the pair of sealing members including a first sealing member formed on a lower side of the first spray arm and a second sealing member formed in an upper side of the second spray arm to correspond to the first sealing member, and a pair of rotation guides in the shaft hole to guide a rotation of the second spray arm and the shaft, the pair of rotation guides including a first rotation guide and a second rotation guide vertically spaced part from the first rotation guide. 
     The dishwasher may further include a ring-shaped holder on a lower side of the second spray arm and coupled to the outer peripheral surface of the shaft to support the second spray arm. 
     The dishwasher may further include a communication hole formed in the shaft to allow a portion of the washing water, which is guided by the shaft, to branch into the second spray arm. 
     In accordance with another aspect of the disclosure a dishwasher includes a tub forming a washing chamber, a sump to store washing water in the washing chamber, and a spray device in a lower portion of the tub to spray the washing water to an inside of the washing chamber. The spray device may include a shaft to guide the washing water introduced from the sump, the shaft having a truncated cone shaped in which a diameter thereof is increased as a distance to an upper portion is reduced, a first spray blade integrally extending from an upper end of the shaft to form a first flow path into which a portion of the washing water guided by the shaft is introduced, a second spray blade coupled to a lower side of the first spray blade and an outer peripheral surface of the shaft, and to form a second flow path into which a remaining portion of the washing water guided by the shaft is introduced, a holder on a lower side of the second spray blade to be coupled to the outer peripheral surface of the shaft to support the second spray blade, and a supporting tube into which the shaft and the holder are inserted to support the shaft. 
     The shaft may further include a communication hole formed therein to communicate with the second flow path of the second spray blade. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects of the disclosure will become apparent and more readily appreciated from the following description of embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG.  1    is a schematic perspective view illustrating a dishwasher according to an embodiment of the disclosure; 
         FIG.  2    is a schematic side view illustrating the dishwasher according to an embodiment of the disclosure; 
         FIG.  3    is a perspective view illustrating an example of a spray device of the dishwasher according to an embodiment of the disclosure; 
         FIG.  4    is an exploded view illustrating an example of the spray device of the dishwasher according to an embodiment of the disclosure; 
         FIG.  5    is an exploded view illustrating the spray device of  FIG.  4    when viewed from another direction; 
         FIG.  6    is an exploded cross-sectional view illustrating an example of the spray device of the dishwasher according to an embodiment of the disclosure; 
         FIG.  7    is a view illustrating a part, which is cut, of an example of the spray device of the dishwasher according to an embodiment of the disclosure; 
         FIG.  8    is a view illustrating the spray device of  FIG.  7    when viewed from a cut surface; 
         FIG.  9    is an enlarged-view illustrating a part of an upper portion of the spray device of  FIG.  8   ; and 
         FIG.  10    is an enlarged-view illustrating a part of a lower portion of the spray device of  FIG.  8   . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments described in the disclosure and configurations illustrated in the drawings are merely examples of the embodiments of the disclosure, and may be modified in various different ways at the time of filing of the present application to replace the embodiments and drawings of the disclosure. 
     In addition, the same reference numerals or signs illustrated in the drawings of the disclosure indicate elements or components performing substantially the same function. 
     Also, the terms used herein are used to describe the embodiments and are not intended to limit and/or restrict the disclosure. The singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. In this disclosure, the terms “including”, “having”, and the like are used to specify features, numbers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more of the features, elements, steps, operations, elements, components, or combinations thereof. 
     It will be understood that when an element is referred to as being “connected” another element, it can be directly or indirectly connected to the other element. Similarly, it will be understood that when an element is referred to as being “coupled” another element, it can be directly or indirectly coupled to the other element. 
     Throughout the description, when a member is “on” another member, this includes not only when the member is in contact with the other member, but also when there is another member between the two members. 
     It will be understood that, although the terms first, second, third, etc., may be used herein to describe various elements, but elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the disclosure, a first element may be termed as a second element, and a second element may be termed as a first element. The term of “and/or” includes a plurality of combinations of relevant items or any one item among a plurality of relevant items. 
     The terms of “front and rear”, “front”, “rear”, “upper”, “lower”, “vertical direction”, “height direction”, etc. used in the following description are defined based on the drawings, but the shape and the location of the component is not limited by the term. For example, as shown in  FIG.  1   , a direction in which a door  20  faces in a dishwasher  1  may be defined as a front side (+X direction), and the opposite direction may be defined as a rear side (−X direction). A direction in which a plurality of baskets is arranged in the dishwasher  1  may be defined as a vertical direction or a height direction (Z direction). 
     Hereinafter an embodiment according to the disclosure will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a schematic perspective view illustrating a dishwasher according to an embodiment of the disclosure.  FIG.  2    is a schematic side view illustrating the dishwasher according to an embodiment of the disclosure. 
     Referring to  FIGS.  1  and  2   , the dishwasher  1  may include a main body  10 . The main body  10  may form an appearance thereof. 
     The dishwasher  1  may include a tub  12  arranged inside the main body  10 . The tub  12  may be formed in a substantially box shape. One side of the tub  12  may be openable. That is, the tub  12  may include an opening  12 a. As an example, a front surface of the tub  12  may be openable. 
     The dishwasher  1  may include a door  11  configured to open and close the opening  12   a  of the tub  12 . The door  11  may be installed in the main body  10  to open and close the opening  12   a  of the tub  12 . The door  11  may be rotatably installed in the main body  10 . The door  11  may be removably mounted to the main body  10 . 
     The dishwasher  1  may further include a storage container arranged in the tub  12  to accommodate dishes. 
     The storage container may include a plurality of baskets  51 ,  52  and  53 . Relatively large dishes may be stored in the plurality of baskets  51 ,  52 , and  53 . However, the kind of dishes accommodated in the plurality of baskets  51 ,  52 , and  53  is not limited to relatively large dishes. That is, the plurality of baskets  51 ,  52  and  53  may accommodate not only relatively large dishes but also relatively small dishes. 
     The storage container may include an intermediate basket  52  positioned in the middle with respect to the height direction of the dishwasher  1 , and a lower basket  51  positioned in a lower portion with respect to the height direction of the dishwasher  1 . The intermediate basket  52  may be provided to be supported by an intermediate guide rack  13   a , and the lower basket  51  may be provided to be supported by a lower guide rack  13   b . The intermediate guide rack  13   a  and the lower guide rack  13   b  may be installed on a side surface  12   d  of the tub  12  so as to be slidable toward the opening  12   a  of the tub  12 . Particularly, the intermediate guide rack  13   a  and the lower guide rack  13   b  may be installed on an inner surface of the side surface  12   d  of the tub  12 . 
     The storage container may include an upper basket  53  positioned in an upper portion with respect to the height direction of the dishwasher  1 . The upper basket  53  may be formed in a rack assembly to accommodate relatively small dishes. It is appropriate that the upper basket  53  may contain a cooking utensil such as a ladle, a knife, or a turner, or cutlery. In addition, the rack assembly may accommodate a small cup such as an espresso cup. However, the kind of dishes accommodated in the upper basket  53  is not limited to the above example. 
     In addition, the shape of the storage container is not limited to the shape shown in  FIGS.  1  and  2   . For example, the upper basket  53  may not be included according to the size of the tub  12 . Therefore, the storage container may be implemented only with the intermediate basket  52  and the lower basket  51 . 
     The dishwasher  1  may include a washing chamber C formed inside the tub  12 . 
     The washing chamber C may be defined as an inner space of the tub  12 . 
     The dishwasher  1  may include a sump  70  configured to store washing water. The sump  70  may be configured to collect washing water and pump the washing water. For example, a lower surface  12   b  of the tub  12  may be inclined toward the sump  70  to allow the sump  70  to easily collect washing water, and the washing water flowing along the lower surface  12   b  of the tub  12  may be collected in the sump  70 . 
     The sump  70  may be configured to supply the pumped washing water to the tub  12 . For example, the sump  70  may include a washing pump (also referred to as a circulation pump)  30  configured to pump washing water, and a pump motor (not shown) configured to drive the washing pump  30 . Further, the sump  70  may be arranged below the tub  12  to easily collect the washing water. 
     The dishwasher  1  may include a spray device  100  configured to spray washing water. 
     The spray device  100  may include a plurality of spray devices  41 ,  42 , and  43 . The plurality of spray devices  41 ,  42 , and  43  may include a first spray device  41  arranged below the lower basket  51  in the height direction of the dishwasher  1 , a second spray device  42  arranged below the intermediate basket  52  in the height direction of the dishwasher  1 , and a third spray device  43  arranged above the upper basket  53  in the height direction of the dishwasher  1 . 
     The first spray device  41 , the second spray device  42 , and the third spray device  43  may be configured to spray washing water while rotating. 
     However, the spray devices  41 ,  42  and  43  may spray washing water in a method different from the above-mentioned example. For example, the first spray device  41  may be fixed to one side of the lower surface  12   b  unlike the second spray device  42  and the third spray device  43 . In this case, the first spray device  41  may be configured to spray washing water in a substantially horizontal direction by a fixed nozzle, and the washing water sprayed in the horizontal direction from the nozzle of the first spray device  41  may be directed to the upper side because a direction of the sprayed water is changed by a switching assembly. The switching assembly may be installed on a rail by a holder and translated along the rail. 
     The third spray device  43  may spray the washing water toward the dishes stored in the upper basket  53 , the intermediate basket  52 , and the lower basket  51 . The second spray device  42  may spray the washing water toward the dishes stored in the intermediate basket  52  and the upper basket  53 . 
     The first spray device  41  may be arranged in a lower portion of the washing chamber C. For example, the first spray device  41  may be arranged on the lower surface  12   b  of the tub  12 . The first spray device  41  may be connected to the sump  70 . 
     The dishwasher  1  may include a circulation pump  30  configured to pump water stored in the sump  70  toward the spray device  100 . The washing water pumped by the circulation pump  30  may be supplied to the first spray device  41  through an alternating device  80  connected to the circulation pump  30 . Alternatively, the washing water pumped by the circulation pump  30  may be moved upward by a duct  90  and then supplied to the second spray device  42  or the third spray device  43 . 
     The washing water stored in the sump  70  or washing water introduced into the dishwasher  1  from the outside may flow to the alternating device  80  by the circulation pump  30 . 
     The alternating device  80  may supply the washing water to the first spray device  41  through a connector  81  connected to the first spray device  41 , and may supply the washing water to the duct  90  through a flow path  62  connected to the duct  90 . The alternating device  80  may supply the washing water to at least one of the connector  81  and the duct  90 . 
     The dishwasher  1  may include a machine room L arranged below the tub  12 . A configuration for circulating washing water may be arranged in the machine room L. 
     For example, at least a part of the connector  81 , and the flow path  62  may be arranged in the machine room L arranged below the washing chamber C. That is, at least a part of the connector  81  and the flow path  62  may be arranged lower than the lower surface  12   b  of the tub  12  with respect to the height direction of the dishwasher  1 . 
     Through the connector  81  and the flow path  62 , the washing water may flow to the first spray device  41  and the duct  90  arranged inside the washing chamber C. The washing water may flow to the second spray device  42  and the third spray device  43  through the duct  90 . 
     The above-described circulation pump  30 , and sump  70 , and alternating device  80  may be arranged in the machine room L and further a water supply hose (not shown) and a drain hose (not shown) may be arranged in the machine room L. 
     A capacity of the washing chamber C may be increased or decreased according to a height of the machine room L. As the height of the machine room L is reduced, the height of the washing chamber C may be increased. That is, in order to secure the capacity of the washing chamber C, it is required to reduce the height of the machine room L by arranging the components arranged in the machine room L compactly. 
       FIG.  3    is a perspective view illustrating an example of a spray device of the dishwasher according to an embodiment of the disclosure.  FIG.  4    is an exploded view illustrating an example of the spray device of the dishwasher according to an embodiment of the disclosure.  FIG.  5    is an exploded view illustrating the spray device of  FIG.  4    when viewed from another direction.  FIG.  6    is an exploded cross-sectional view illustrating an example of the spray device of the dishwasher according to an embodiment of the disclosure. 
     The spray device  100  according to an embodiment will be described with reference to the first spray device  41 . The spray device  100  to be described below is not limited to the first spray device  41 , and may be the second spray device  42  or the third spray device  43 . That is, it will be understood that a structure of the first spray device  41  to be described below is applied to the second spray device  42  and the third spray device  43 . 
     Referring to  FIGS.  3  to  6   , the spray device  100  may include a first spray rotor  110  and a second spray rotor  120 . 
     The first spray rotor  110  may include a first spray arm  111  configured to spray washing water, and a shaft  130  integrally formed with the first spray arm  111 . The shaft  130  may extend from the first spray arm  111 . 
     The first spray arm  111  may be configured to spray washing water while rotating in a first direction R 1 . The first spray arm  111  may include a shape extending in one direction. For example, the first spray arm  111  may extend in one direction perpendicular to the extending direction of the shaft  130 . 
     A first flow path  112  through which the washing water flows may be formed inside the first spray arm  111 . A first nozzle  113  provided to spray washing water toward the washing chamber C may be formed in the first spray arm  111 . The washing water flowing in the first flow path  112  may be sprayed through the first nozzle  113  communicating with the first flow path  112 . The washing water sprayed through the first nozzle  113  may collide with the dishes to generate a strong washing power. 
     The first nozzle  113  may be provided in plurality, and the plurality of first nozzles  113  may be arranged to be spaced apart from each other in a longitudinal direction of the first spray arm  111 . 
     The first spray arm  111  may be configured as an assembly. For example, the first spray arm  111  may include an upper body  111   a  and a lower body  111   b  coupled to a lower side of the upper body  111 a. As the upper body  111   a  and the lower body  111   b  are coupled to each other, the first flow path  112  may be formed in the first spray arm  111 . In this case, the lower body  111   b  may be integrally formed with the shaft  130 . However, the disclosure is not limited thereto, and the first spray arm  111  may be provided as a single structure. 
     Further, the first spray arm  111  may be referred to as a first spray blade. 
     The shaft  130  may be integrally formed with the first spray arm  111 . The shaft  130  may communicate with the first spray arm  111 . The shaft  130  may extend in a vertical direction from the first spray arm  111 . 
     The shaft  130  may guide the washing water supplied from the sump  70  to the first spray arm  111 . 
     The shaft  130  may include a truncated cone shape in which a diameter is decreased as the distance from the first spray arm  111  is increased. Because the shaft  130  is formed in a truncated cone shape, an area, through which the washing water passes, gradually increases as the shaft  130  approaches the first spray arm  111 . Accordingly, a speed of the washing water may decrease and a pressure of the washing water may increase. That is, in a process in which the washing water is guided by the shaft  130 , the pressure of the washing water may be increased. As a result, as the pressure of the washing water sprayed through the spray device  100  increases, the washing power of the spray device  100  may be increased. 
     The shaft  130  may include a shaft body  131  forming an exterior and a guide flow path  132  formed inside the shaft body  131  to guide the washing water supplied from the sump  70 . The shaft body  131  includes an outer peripheral surface  131   a  and an inner peripheral surface  131 b. The washing water stored in the sump  70  may be introduced through an end of the shaft  130  and flow through the guide flow path  132 , and then introduced into the first flow path  112  of the first spray arm  111  and a second flow path  122  of a second spray arm  121 . 
     The shaft  130  may be coupled to the second spray rotor  120 . The shaft  130  may be coupled to a holder  140  to be described later. For example, the shaft  130  may include a hook groove  134  corresponding to a first hook  147  of the holder  140 . The hook groove  134  may be formed in an outer peripheral surface  131   a  of the shaft  130 . The hook groove  134  may be provided in plurality, and the plurality of hook grooves  134  may be arranged to be spaced apart from each other along a peripheral direction of the outer peripheral surface  131   a  of the shaft  130 . 
     The shaft  130  may include at least one communication hole  133  formed in the shaft body  131 . The communication hole  133  may be provided to communicate with the second flow path  122  of the second spray rotor  120 . That is, the guide flow path  132  of the shaft  130  and the second flow path  122  of the second spray rotor  120  may communicate through the communication hole  133 . Accordingly, the communication hole  133  may guide a portion of the washing water, which is guided to the first spray arm  111  by the guide flow path  132 , to flow into the second spray arm  121 . That is, a portion of the washing water guided to the first spray arm  111  by the guide flow path  132  may be branched into the second spray arm  121 . A detailed description of this will be provided later. 
     A first support protrusion  138  may be formed on the outer peripheral surface  131   a  of the shaft  130 . The first support protrusion  138  may be arranged adjacent to an end side of the shaft  130 . The first support protrusion  138  may be provided in plurality. The plurality of first support protrusions  138  may be provided to be spaced apart from each other along the peripheral direction of the outer peripheral surface  131   a  of the shaft  130 . The first support protrusion  138  may be provided to be in contact with a supporting tube  150  to be described later. 
     The first spray rotor  110  may include a sealing member  115  provided to prevent leakage of washing water. A detailed description of this will be provided later. 
     The first spray rotor  110  may include curved members  161  and  162  provided to smooth the flow of washing water. A pressure loss of the washing water may occur in the process of moving to the spray device  100  through the sump  70 , and the curved members  161  and  162  may be provided to reduce the pressure loss of the washing water. 
     For example, the curved members  161  and  162  may include a first curved member  161  provided to be curved between the shaft  130  and the first spray arm  111 . The curved members  161  and  162  may include a second curved member  162  provided to allow an upper inner surface of the shaft  130  to be curved. 
     The second spray rotor  120  may be coupled to the first spray rotor  110 . The second spray rotor  120  may be rotatably coupled to the shaft  130 . 
     The second spray rotor  120  may include the second spray arm  121  configured to spray washing water. The second spray arm  121  may be provided to surround the shaft  130 . 
     The second spray arm  121  may be provided to spray washing water while rotating in a second direction R 2 . For example, the second direction R 2  may be opposite to the first direction R 1 . That is, the first spray arm  111  and the second spray arm  121  may spray washing water while rotating in opposite directions. Accordingly, the spray device  100  may spray the washing water in a wide range. However, the disclosure is not limited thereto, and the first spray arm  111  and the second spray arm  121  may rotate in the same direction. In addition, the first spray arm  111  and the second spray arm  121  may rotate at the same speed or at different speeds. 
     The second spray arm  121  may include a shape extending in one direction. For example, the second spray arm  121  may extend in one direction perpendicular to the extending direction of the shaft  130 . 
     For example, the lower surface  12   b  of the tub  12  may be inclined downward, and additional components configured to wash dishes may be arranged on the lower surface  12   b  of the tub  120 . Accordingly, a length L 2  of the second spray arm  121  may be less than a length L 1  of the first spray arm  111 . That is, for a compact arrangement in the washing chamber C, the length of the first spray arm  111  and the length of the second spray arm  121  may be adjusted. 
     The second flow path  122  through which the washing water flows may be formed inside the second spray arm  121 . A second nozzle  123  provided to spray washing water toward the washing chamber C may be formed in the second spray arm  121 . The washing water flowing in the second flow path  122  may be sprayed through the second nozzle  123  communicating with the second flow path  122 . The washing water sprayed through the second nozzle  123  may collide with the dishes to generate a strong washing power. 
     The second nozzle  123  may be provided in plurality, and the plurality of second nozzles  123  may be arranged to be spaced apart from each other in a longitudinal direction of the second spray arm  121 . 
     Meanwhile, the number of the plurality of first nozzles  113  may be greater than the number of the plurality of second nozzles  123 . Accordingly, a flow rate of the washing water W 1  flowing to the first flow path  112  may be greater than a flow rate of the washing water W 2  flowing into the second flow path  122 . However, the disclosure is not limited thereto, and the number of the plurality of first nozzles  113  may be less than or equal to the number of the plurality of second nozzles  123 . 
     The second spray arm  121  may be configured as an assembly. For example, the second spray arm  121  may include an upper body  121   a  and a lower body  121   b  coupled to a lower side of the upper body  121 a. As the upper body  121   a  and the lower body  121   b  are coupled to each other, the second flow path  122  may be formed in the second spray arm  121 . However, the disclosure is not limited thereto, and the second spray arm  121  may be provided as a single structure. 
     Further, the second spray arm  121  may be referred to as a second spray blade. 
     The second spray rotor  120  may include a shaft hole  124  formed in the second spray arm  121  to allow the shaft  130  to pass therethrough. The shaft hole  124  may be formed in a central portion of the second spray arm  121 . For example, the shaft hole  124  may include a first shaft hole  1241  formed in the upper body  121   a  and a second shaft hole  1242  formed in the lower body  121   b.    
     The second spray rotor  120  may include a rotation guide  128  formed in the shaft hole  124  to reduce friction with the shaft  130  during rotation. The rotation guide  128  may reduce a frictional resistance with the shaft  130  to promote a smooth rotation of the second spray rotor  120 . 
     The rotation guide  128  may include a plurality of guide protrusions  1281   a  and  1282   a  protruding toward the shaft  130  so as to be in contact with the outer peripheral surface of the shaft  130  and spaced apart along the peripheral direction of the shaft hole  124 . In addition, as the plurality of guide protrusions  1281   a  and  1282   a  protrude inward by a predetermined length in the radial direction, a gap may be generated between a region, in which the plurality of guide protrusions  1281   a  and  1282   a  is not formed in the rotation guide  128 , and the shaft  130 . Through the predetermined gap, very small food residues and the like (for example, coffee powder) may be easily discharged. In addition, the plurality of guide protrusions  1281   a  and  1282   a  may support the outer peripheral surface of the shaft  130 . The plurality of guide protrusions  1281   a  and  1282   a  may be arranged along the peripheral direction of the shaft hole  124  at regular intervals, and may support the outer peripheral surface of the shaft  130  with a uniform force. Therefore, the vibration of the shaft  130  may be reduced, and excessive water leakage between the shaft  130  and the second spray rotor  120  may be prevented. 
     For example, the rotation guide  128  may include a first rotation guide  1281  formed in the first shaft hole  1241  of the upper body  121   a  and a second rotation guide  1282  formed in the second shaft hole of the lower body  121   b . The first rotation guide  1281  may include the plurality of first guide protrusions  1281   a  protruding toward the shaft  130  and spaced apart from each other in the peripheral direction of the first shaft hole  1241 . The second rotation guide  1282  may include the plurality of second guide protrusions  1282   a  protruding toward the shaft  130  and spaced apart from each other in the peripheral direction of the second shaft hole  1242 . 
     For example, the first rotation guide  1281  and the second rotation guide  1282  may be provided as a pair. 
     The second rotation guide  1282  may be vertically spaced apart from the first rotation guide  1281 . That is, an upper portion and a lower portion of the shaft  130 , to which the second spray rotor  120  is coupled, are supported by the first rotation guide  1281  and the second rotation guide  1282 , and thus during the rotation of the shaft  130 , the vibration of the shaft  130  may be reduced. 
     The second spray rotor  120  may include sealing member  125  and  126  provided to prevent leakage of washing water. A detailed description of this will be provided later. 
     The dishwasher  1  may further include the holder  140  provided to support the second spray rotor  120 . The holder  140  may be arranged below the second spray rotor  120 . The holder  140  may be coupled to the outer peripheral surface of the shaft  130 . 
     The holder  140  may include a holder body  141  forming a hollow  142 . The shaft  130  may be inserted into the hollow  142  of the holder  140 . The shaft  130  may be fitted into the hollow  142  of the holder  140 . The holder body  141  may surround the outer peripheral surface of the shaft  130 . The holder  140  may include a substantially ring shape. 
     The holder body  141  may include the first hook  147  protruding toward the shaft  130  from an inner peripheral surface  141   b  of the holder body  141 . The first hook  147  may be formed on one side of the inner peripheral surface  141   b  adjacent to the second spray rotor  120 . For example, the first hook  147  may be provided in plurality, and the plurality of first hooks  127  may be arranged to be spaced apart from each other along a peripheral direction of the inner peripheral surface  141   b  of the holder body  141 . 
     The first hook  147  may correspond to the hook groove  134  formed on the outer peripheral surface  131   a  of the shaft  130 . The first hook  147  may be provided to engage the hook groove  134 . Accordingly, the hook  140  and the shaft  130  may be stably coupled to each other, and the vibration of the first spray rotor  110  may be reduced. In addition, an assembling property of the spray device  100  may be improved. 
     A shaft support  145  provided to support the outer peripheral surface  131   a  of the shaft  130  may be provided on the inner peripheral surface  141   b  of the holder body  141 . The shaft support  145  may protrude toward the shaft  130 . The shaft support  145  may be formed on one side of the inner peripheral surface  141   b  far from the second spray rotor  120 . For example, the shaft support  145  may elastically support the outer peripheral surface  131   a  of the shaft  130 . 
     The holder  140  may include a rotor support  143  provided to support the lower portion of the second spray rotor  120 . A part of a lower portion of the second spray arm  121  of the second spray rotor  120  may be mounted on the rotor support  143 . The rotor support  143  may extend radially from an upper end of the holder body  141 . For example, a maximum diameter of the rotor support  143  may be greater than a maximum diameter of the holder body  141  and thus the rotor support  143  may stably support the second spray rotor  120 . 
     The holder  140  may include an extension  144  extending from the rotor support  143 . The extension  144  may extend downward. 
     The holder  140  may include a flange hook (second hook)  148  formed on an inner surface of the extension  144  to engage a flange  153  of the supporting tube  150  to be described later. The flange hook  148  may protrude radially inward toward the flange  153 . For example, the flange hook  148  may be provided in plurality, and the plurality of flange hooks  148  may be arranged to be spaced apart from each other along a peripheral direction of the extension  144 . 
     The holder  140  may include a second support protrusion  149  formed on an outer peripheral surface  141   a  of the holder body  141 . The second support protrusion  149  may be arranged on the side of the outer peripheral surface  141   a  adjacent to the second spray rotor  120 . The second support protrusion  149  may be provided in plurality. The plurality of second support protrusions  149  may be provided to be spaced apart from each other along a peripheral direction of the outer peripheral surface  141   a  of the holder body  141 . The second support protrusion  149  may be provided to be in contact with the supporting tube  150  to be described later. 
     The holder  140  may include a sealing member  146  provided to prevent leakage of washing water. A detailed description of this will be provided later. 
     The spray device  100  may be formed of a material resistant to chemical deformation, thermal deformation, and the like. For example, the spray device  100  may be formed of a material such as polypropylene (PP), or polyoxymethylene (POM). However, the disclosure is not limited thereto, and the spray device  100  may be formed of various materials having excellent corrosion resistance and heat resistance. 
     The first spray rotor  110  and the second spray rotor  120  may be formed of a material different from that of the holder  140 . Accordingly, a frictional resistance between the first spray rotor  110  and the holder  140  may be reduced, and a frictional resistance between the second spray rotor  120  and the holder  140  may be reduced. That is, the first spray rotor  110  and the second spray rotor  120  may rotate more smoothly. For example, the first spray rotor  110  and the second spray rotor  120  may be formed of a polypropylene (PP) material, and the holder  140  may be formed of a polyoxymethylene (POM) material. However, the disclosure is not limited thereto, and it is sufficient that the first and second spray rotors  110  and  120  and the holder  140  are formed of different materials to reduce friction. Alternatively, the first and second spray rotors  110  and  120  and the holder  140  may be formed of the same material. 
     In addition, each of the first spray rotor  110 , the second spray rotor  120 , and the holder  140  may include only one material as an integral body, or may include a plurality of materials as necessary. For example, the first spray rotor  110 , the second spray rotor  120 , and the holder  140  may be provided such that only a material of a member coupled to the other component is different. For example, only the material of the sealing member and the rotation guide may be provided to be different. 
       FIG.  7    is a view illustrating a part, which is cut, of an example of the spray device of the dishwasher according to an embodiment of the disclosure.  FIG.  8    is a view illustrating the spray device of  FIG.  7    when viewed from a cut surface.  FIG.  9    is an enlarged-view illustrating a part of an upper portion of the spray device of  FIG.  8   .  FIG.  10    is an enlarged-view illustrating a part of a lower portion of the spray device of  FIG.  8   . 
     Referring to  FIGS.  7  to  10   , the dishwasher  1  may further include the supporting tube  150  provided to support the outer peripheral surface  131   a  of the shaft  130 . 
     The supporting tube  150  may be provided such that one end thereof is connected to the holder  140  and the other end thereof is connected to the sump  70 . The other end of the supporting tube  150  may receive washing water through the connector  81  connected to the sump  70 . The washing water may be introduced into the other end of the supporting tube  150 . 
     The supporting tube  150  may include a tube body  151  forming a hollow  152 . The tube body  151  may form an exterior of the supporting tube  150 . 
     The supporting tube  150  may include the flange  153  bent radially outward from one end. The flange  153  may be provided to engage the flange hook (second hook)  148  of the holder  140 . The separation of the flange  153  may be prevented by the flange hook  148  of the holder  140 . 
     Referring to  FIG.  8   , the shaft  130  may include the first support protrusion  138  protruding to be in contact with an inner peripheral surface  151   b  of the supporting tube  150 . The holder  140  may include the second support protrusion  149  protruding to be in contact with the inner peripheral surface of the supporting tube  150 . The first support protrusion  138  may be formed on the outer peripheral surface  131   a  of the shaft  130  to correspond to the inner surface  151   b  of a portion of the supporting tube  150 , and the second support protrusion  149  may be formed on the outer peripheral surface  141   a  to correspond to the inner surface  151   b  of another portion of the supporting tube  150 . 
     For example, the first support protrusion  138  and the second support protrusion  149  may be vertically spaced apart from each other. Accordingly, a portion corresponding to a relatively upper side of the supporting tube  150  may be in close contact with the first support protrusion  138 , and a portion corresponding to a relatively lower side of the supporting tube  150  may be in close contact with the second support protrusion  149 . Accordingly, the shaft  130  inserted into the hollow  152  of the supporting tube  150  may be supported. A portion corresponding to a relatively lower side of the shaft  130  may be supported by the supporting tube  150  and the first support protrusion  138 . A portion corresponding to a relatively upper side of the shaft  130  may be supported by the supporting tube  150  and the second support protrusion  149 . 
     That is, because the upper and lower portions of the shaft  130  are supported by the supporting tube  150  and the support protrusions  138  and  149 , the vibration of the shaft  130  may be effectively reduced. 
     Referring to  FIGS.  6  to  9   , the first spray rotor  110  may include the first sealing member  115 . The first sealing member  115  may be arranged adjacent to the shaft  130 . The first sealing member  115  may be arranged adjacent to the second spray rotor  120 . 
     The first sealing member  115  may include at least one first sealing protrusion  1151  protruding toward the second spray arm  121  of the second spray rotor  120 . The first sealing protrusion  1151  may extend integrally from the lower body  111   b  of the first spray arm  111 . The first sealing member  115  may include at least one first sealing groove  1152  arranged adjacent to the first sealing protrusion  1151 . The first sealing protrusion  1151  and the first sealing groove  1152  may be alternately formed in the radial direction. 
     For example, the first sealing protrusion  1151  may include a ring shape. The first sealing protrusion  1151  may extend along the peripheral direction of the shaft  130 . The first sealing protrusion  1151  may include a shape surrounding the shaft  130 . A portion of the first sealing protrusion  1151  may be cut out. For example, the first sealing member  115  may include a cutout  1153  in which the first sealing protrusion  1151  is partially cut out. That is, when it is assumed that the first sealing protrusion  1151  includes a ring shape, the ring shape may include an intermittent ring shape as well as a continuous ring shape. The cutout  1153  may be provided to prevent refuse such as food waste from being caught. 
     Based on the first sealing protrusion  1151  being provided in plurality, the protrusions  1151   a  and  1151   b  having different diameters may be formed to share the same center. That is, the protrusions  1151   a  and  1151   b  may be provided as concentric circles. At least one first sealing groove  1152  may be provided between the protrusions  1151   a  and  1151   b  or between the protrusion  1151   a  and the shaft  130 . 
     The second spray rotor  120  may include the second sealing member  125  corresponding to the first sealing member  115 . The second sealing member  125  may be arranged adjacent to the first spray arm  111  of the first spray rotor  110 . The second sealing member  125  may be arranged adjacent to the shaft hole  124 . The second sealing member  125  may be arranged adjacent to the first shaft hole  1241  provided in the upper body  121   a  of the second spray arm  121 . 
     The second sealing member  125  may include at least one second sealing protrusion  1251  protruding toward the first spray arm  111  of the first spray rotor  110 . 
     The second sealing protrusion  1251  may extend integrally from the upper body  121   a  of the second spray arm  121 . The second sealing member  125  may include at least one second sealing groove  1252  arranged adjacent to the second sealing protrusion  1251 . The second sealing protrusion  1251  and the second sealing groove  1252  may be alternately formed in the radial direction. 
     For example, the second sealing protrusion  1251  may include a ring shape. The second sealing protrusion  1251  may extend along the peripheral direction of the shaft hole  124 . A portion of the second sealing protrusion  1251  may be cut out. For example, the second sealing member  125  may include a cutout  1253  in which a portion of the second sealing protrusion  1251  is cut out. That is, when it is assumed that the second sealing protrusion  1251  includes a ring shape, the ring shape may include an intermittent ring shape as well as a continuous ring shape. The cutout  1253  may be configured to prevent refuse such as food waste from being caught. 
     Further, the cutouts  1153  and  1253  may be provided in at least one of the first sealing member  115  and the second sealing member  125 . That is, the cutout may be provided only in the first sealing member  115 , only in the second sealing member  125 , or may be provided in both the first sealing member  115  and the second sealing member  125 . 
     Based on the second sealing protrusion  1251  being provided in plurality, the protrusions  1251   a  and  1251   b  having different diameters may be formed to share the same center. That is, the protrusions  1251   a  and  1251   b  may be provided as concentric circles. At least one second sealing groove  1252  may be provided between the protrusions  1251   a  and  1251   b.    
     The first sealing member  115  of the first spray rotor  110  and the second sealing member  125  of the second spray rotor  120  may be coupled to each other to reduce leakage of washing water. 
     For example, the first sealing member  115  and the second sealing member  125  may be provided in a labyrinth seal structure. At least one first sealing protrusion  1151  of the first sealing member  115  may be inserted into the at least one second sealing groove  1252  of the second sealing member  125 . At least one second sealing protrusion  1251  of the second sealing member  125  may be inserted into the at least one first sealing groove  1152  of the first sealing member  115 . The at least one second sealing protrusion  1251  may be provided to be alternately arranged with the first sealing protrusion  1151  in the radial direction. 
     In a conventional dishwasher in which the spray device is provided with a plurality of rotors, a ball bearing or a roller bearing may be provided between the plurality of rotors. The ball bearing or roller bearing may be used for coupling between the plurality of rotors or to reduce friction. However, refuse such as food waste may be caught between the rolling element (ball or roller) and a case thereof. That is, the ball bearing or roller bearing may be susceptible to contamination. 
     In contrast, a predetermined gap g 1  may be provided between the first sealing member  115  and the second sealing member  125 . Even if refuse is caught between the sealing members, washing water may flow in the gap g 1  and thus the refuse may be easily washed. That is, the structure of the sealing members  115  and  125  of the disclosed spray device  100  may be resistant to contamination. Accordingly, the cleaning of the spray device  100  becomes easier, and thus the ease of use may be improved. 
     In addition, the cutouts  1153  and  1253  may be provided in at least one of the first sealing member  115  and the second sealing member  125 , and thus even when refuse such as food waste is introduced into between the first sealing member  115  and the second sealing member  115 , the refuse may easily escape through the cutout. That is, the refuse caught between the first sealing member  115  and the second sealing member  125  may be easily discharged to the outside of the spray device  100  through the cutouts  1153  and  1253 . Accordingly, the cleaning of the spray device  100  is easy. 
     For example, the first sealing member  115  and the second sealing member  125  may be provided in a pair. 
     The second spray rotor  120  may include the third sealing member  126 . The third sealing member  126  may be arranged adjacent to the holder  140 . The third sealing member  126  may be arranged adjacent to the shaft hole  124 . The third sealing member  126  may be arranged adjacent to the second shaft hole  1242  provided in the lower body  121   b  of the second spray arm  121 . 
     The third sealing member  126  may include at least one third sealing protrusion  1261  protruding toward the holder  140 . The third sealing protrusion  1261  may extend integrally from the lower body  121   b  of the second spray arm  121 . The third sealing member  126  may include at least one third sealing groove  1261  arranged adjacent to the third sealing protrusion  1261 . The third sealing protrusion  1261  and the third sealing groove  1261  may be alternately formed in the radial direction. 
     For example, the third sealing protrusion  1261  may include a ring shape. The third sealing protrusion  1261  may extend along the peripheral direction of the shaft hole  124 . A portion of the third sealing protrusion may be cut out. For example, the third sealing member  126  may include a cutout (not shown) in which a part of the third sealing protrusion is cut out to allow foreign substances such as food waste to easily escape. 
     On the drawings, the third sealing protrusion  1261  is illustrated as a protrusion including a single ring shape, but the disclosure is not limited thereto. Accordingly, the third sealing protrusion  1261  may be provided in plurality. For example, the plurality of third sealing protrusions may be provided in concentric circles, and at least one third sealing groove may be provided between the plurality of third sealing protrusions. 
     The holder  140  may include the fourth sealing member  146  corresponding to the third sealing member  126 . The fourth sealing member  146  may be arranged adjacent to the second spray rotor  120 . The fourth sealing member  146  may be provided at the upper end of the holder body  141 . The fourth sealing member  146  may be arranged adjacent to the hollow  142 . 
     The fourth sealing member  146  may include at least one fourth sealing protrusion  1461  protruding toward the second spray rotor  120 . The fourth sealing protrusion  1461  may extend integrally from the holder body  141 . The fourth sealing member  146  may include at least one fourth sealing groove  1462  arranged adjacent to the fourth sealing protrusion  1461 . The fourth sealing protrusion  1461  and the fourth sealing groove  1462  may be alternately formed in the radial direction. For example, the fourth sealing groove  1462  may be provided on the same plane as the rotor support  143 . The fourth sealing protrusion  1461  may be provided to protrude more than the rotor support  143 . 
     For example, the fourth sealing protrusion  1461  may include a ring shape. The fourth sealing protrusion  1461  may extend along the peripheral direction of the hollow  142 . The fourth sealing protrusion  1461  may include a shape surrounding the hollow  142 . A portion of the fourth sealing protrusion  1461  may be cut out. For example, the fourth sealing member  146  may include a cutout (not shown) in which a part of the fourth sealing protrusion  1461  is cut out to allow foreign substances such as food waste to easily escape. 
     Meanwhile, a cutout (not shown) may be provided in at least one of the third sealing member  126  and the fourth sealing member  146 . Even when refuse, such as food waste, is introduced into between the third sealing member  126  and the fourth sealing member  146 , the refuse may easily escape through the cutout, and thus the cleaning of the spray device  100  is easy. 
     For example, the third sealing member  126  and the fourth sealing member  146  may be provided in a pair. 
     On the drawings, the fourth sealing protrusion  1461  is illustrated as a protrusion including a single ring shape, but the disclosure is not limited thereto. Accordingly, the fourth sealing protrusion  1461  may be provided in plurality. For example, the plurality of fourth sealing protrusions may be provided in concentric circles, and at least one fourth sealing groove may be provided between the plurality of fourth sealing protrusions 
     The third sealing member  126  of the second spray rotor  120  and the fourth sealing member  146  of the holder  140  may be coupled to each other to reduce leakage of washing water. 
     For example, the third sealing member  126  and the fourth sealing member  146  may be provided in a labyrinth seal structure. The at least one third sealing protrusion  1261  may be inserted into the at least one fourth sealing groove  1462 . At least one fourth sealing protrusion  1461  of the fourth sealing member  146  may be inserted into the at least one third sealing groove  1262 . The at least one third sealing protrusion  1261  may be provided to be alternately arranged with the at least one fourth sealing protrusion  1461  in the radial direction. 
     A predetermined gap g 2  may be provided between the third sealing member  126  and the fourth sealing member  146 . Even if refuse is caught between the sealing members, washing water may flow in the gap g 2 , and thus the refuse may be easily washed. That is, the structure of the sealing members  126  and  146  of the disclosed spray device  100  may be resistant to contamination in comparison with a structure to which a ball bearing or a roller bearing is applied. 
     Referring to  FIG.  9   , an outermost diameter D of the second sealing protrusion  1251  may be greater than an outermost diameter d of the third sealing protrusion  1261 . The third sealing member  126  may be provided to receive a greater load than the second sealing member  125 , and thus the third sealing member  126  and the fourth sealing member  146  may be in close contact with each other. Accordingly, even when the third sealing protrusion  1261  of the third sealing member  126  protrudes less than the second sealing protrusion  1251  of the second sealing member  125 , the third sealing member  126  and the fourth sealing member  146  corresponding to the third sealing member  126  may effectively prevent leakage of washing water. That is, even when the third sealing member  126  and the fourth sealing member  146  are provided in the shape of a small labyrinth seal, it is possible to sufficiently perform the function of reducing the leakage of washing water. For example, a protruding length A of the second sealing protrusion  1251  may be greater than a protruding length B of the third sealing protrusion  1261 . 
     Further, in the conventional dishwasher, because a separate ball bearing or roller bearing is provided and assembled between the spray rotors, the structure of the spray device may become complicated, and manufacturing cost and manufacturing time may increase. In contrast, the spray device  100  may be configured only by a combination of the first spray rotor  110  and the second spray rotor  120  without a separate ball bearing or roller bearing. That is, because the spray device  100  is provided with a simple structure, the cost and time required for manufacturing the spray device  100  may be greatly reduced. For example, the first sealing member  115  of the first spray rotor  110  may be coupled to the second sealing member  125  of the second spray rotor  120 . The rotation guide  128  provided in the shaft hole  124  of the second spray rotor  120  may be coupled to the outer peripheral surface of the shaft  130  of the first spray rotor  110 . In addition, the holder  140  may be coupled to the outer peripheral surface of the shaft  130 , thereby stably supporting the second spray rotor  120 . 
     Washing water introduced into the spray device  100  may flow into the second spray arm  121  while flowing to the first spray arm  111  along the guide flow path  132  of the shaft  130 . That is, the washing water may be branched into the first flow path  112  and the second flow path  122  while being guided in one guide flow path  132 . Hereinafter an example of a flow process of washing water will be described with reference to  FIGS.  7  and  8   . 
     Washing water stored in the sump  70  may be pumped by the washing pump  30  and introduced into the end of the shaft  130  through the connector  81 . 
     The washing water W introduced into the shaft  130  may flow along the guide flow path  132 . For example, a moving direction of the washing water introduced into the shaft  130  may correspond to the extending direction of the guide flow path  132  of the shaft  130 . For example, the washing water introduced into the shaft  130  may flow upward. 
     The washing water introduced into the shaft  130  may be guided to the first spray arm  111  by the shaft  130 . In this case, the shaft  130  may include a truncated cone shape in which an area increases along the guide direction. Due to the shape of the shaft  130 , the speed and pressure of the washing water may increase in the process of being guided. 
     A portion W 2  of the washing water guided by the shaft  130  may be introduced into the second flow path  122  through the communication hole  133  that connects the guide flow path  132  and the second flow path  122  of the second spray rotor  120 . That is, the portion W 2  of the washing water guided by the shaft  130  may be branched to the second spray arm  121 . The washing water introduced into the second flow path  122  may be sprayed into the washing chamber C through the second nozzle  123 . 
     Washing water W 1 , which is not introduced into the second flow path  122  through the communication hole  133 , may collide with the upper inner surface of the first spray arm  111  during the flow process, and be introduced into the first flow path  112  of the first spray arm  111  extending from the guide flow path  132 . The washing water introduced into the first flow path  112  may be sprayed into the washing chamber C through the first nozzle  113 . 
     For example, because the first spray rotor  110  is relatively closer to the dishes than the second spray rotor  120 , it may be appropriate that an injection pressure of the washing water of the first spray rotor  110  is greater than or equal to an injection pressure of the washing water of the second spray rotor  120  based on the cleaning power efficiency. According to the disclosed example, most of the washing water W flowing into the spray device  100  may flow along the extension direction of the guide flow path  132  and flow into the first flow path  112  integrally connected to the guide flow path  132 . Therefore, a flow rate of the washing water W 1  flowing into the first flow path  112  may be greater than a flow rate of the washing water W 2  flowing into the second flow path  122 . In addition, because the pressure of the washing water increases while being guided by the guide flow path  132 , a hydraulic pressure of the washing water W 1  flowing into the first flow path  112  may be relatively high compared to a hydraulic pressure of the washing water W 2 . Accordingly, the washing water having a strong injection pressure may be sprayed from the first spray rotor  110 . However, this is merely exemplary and is not limited thereto. According to the structure of the washing chamber C, washing water having a stronger injection pressure than that of the first spray rotor  110  may be sprayed from the second spray rotor  120 . 
     Meanwhile, as the washing water W 1  collides with the upper inner surface of the first spray arm  111  while flowing into the first flow path  112 , a pressure loss may occur. A direction of the washing water W 1  may change while flowing into the first flow path  112 , and thus a pressure loss may occur. For example, while the washing water W 1  flows upward along the guide flow path  132  and flows into the first flow path  112  and moves in the left and right directions, a pressure loss may occur. 
     To prevent the pressure loss, the first spray rotor  110  may include curved members  161  and  162  provided to smooth the flow of washing water. The curved members  161  and  162  may be provided to reduce the pressure loss of the washing water. 
     For example, the curved members  161  and  162  may include the first curved member  161  provided to be curved between the shaft  130  and the first spray arm  111 . The curved members  161  and  162  may include the second curved member  162  provided to allow an upper inner surface of the shaft  130  to be curved. Accordingly, the curved members  161  and  162  may reduce the pressure loss of the washing water by preventing a rapid change in the flow direction of the washing water. That is, the flow loss of washing water may be minimized. 
     Although not shown in the drawing, a curved member provided to reduce the pressure loss of the washing water W 2  flowing into the second flow path  122  may be provided. For example, the edge of the communication hole  133  may include a curved shape. Accordingly, the pressure loss of the washing water may be reduced. 
     Flow losses of washing water may be minimized. 
     As is apparent from the above description, a dishwasher may effectively fix a plurality of rotors with a simpler structure. 
     Further, a dishwasher may reduce a pressure loss of washing water supplied to a spray device. 
     Further, a dishwasher may prevent foreign substances from being caught in a spray device. 
     Although a few embodiments of the disclosure 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.