Patent Publication Number: US-11028515-B2

Title: Washing machine

Description:
CROSS-REFERENCE TO RELATED APPLICATION AND CLAIM OF PRIORITY 
     This application is related to and claims priority to of Korean Patent Application No. 10-2017-0028251, filed on Mar. 6, 2017, the contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     Embodiments of the present disclosure relate to a washing machine, more particularly to a washing machine provided with a pulsator. 
     BACKGROUND 
     Generally, a washing machine is a machine that washes laundry using power, and types of washing machine include a drum type washing machine which washes laundry by lifting the laundry along an inner circumferential surface of a rotating tub and dropping the laundry when a rotating tub is horizontally disposed and rotates about a horizontal axis in forward and backward directions, and a vertical-axis washing machine which washes laundry using a water flow generated by a pulsator when a rotating tub with the pulsator vertically disposed in the washing machine rotates about a vertical axis in forward and backward directions. 
     Generally, the drum type washing machine includes a cabinet configured to form an appearance of the drum washing machine, a tub formed in the cabinet to store washing water, a drum rotatably installed in the tub to accommodate laundry, a drive motor disposed in the rear side of the tub to rotate the drum, and a door installed in the front surface of the cabinet. An inlet communicated with the drum is provided in at least one portion of the cabinet, and the door opens and closes and the inlet. 
     Since a pulsator is not applied to the drum type washing machine, it may be impossible for the drum type washing machine to perform the washing by using the water flow in the same manner as the vertical-axis washing machine. 
     SUMMARY 
     To address the above-discussed deficiencies, it is a primary object to provide a washing machine provided with a pulsator. 
     It is another aspect of the present disclosure to provide a washing machine having an improved support structure of a drum. 
     It is another aspect of the present disclosure to provide a washing machine provided with a drum having an improved durability. 
     It is another aspect of the present disclosure to provide a washing machine capable of preventing laundry from being caught on a drum. 
     Additional aspects of the present 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 present disclosure. 
     In accordance with one aspect of the present disclosure, a washing machine may include a cabinet, a tub provided in the cabinet to store washing water, a drum rotatably provided in the tub, a pulsator configured to be rotatable independently of the drum and a flange shaft configured to transmit a rotational force to the drum. The drum may include a cylindrical portion configured to form a side surface of the drum, and a rear cover disposed in one side of the cylindrical portion while being disposed in the outside of the pulsator, and seated in the flange shaft. 
     The rear cover may comprise a drum rear surface configured to form a rear surface of the drum, and a seating flange bent from the drum rear surface to be seated in the flange shaft. 
     The flange shaft may include a flange body coupled to a shaft configured to transmit power from a drive device, a plurality of blades extended radially from the flange body, and a seating member configured to connect the plurality of blades to each other. The seating flange may be seated in at least one of the plurality of blades and the seating member. 
     The flange shaft may include a seating groove formed in at least one of the plurality of blades and the seating member and into which the seating flange is inserted. 
     The seating groove may include a first seating groove formed in the plurality of blades and a second seating groove formed in the seating member, wherein the first and second seating groove are formed in a circular shape with respect to the center of rotation of the drum. 
     The seating flange may include an insertion rib formed to have a greater thickness than a body of the seating flange and configured to be inserted into the seating groove. 
     The insertion rib may be formed by a hemming structure in which an end portion of the seating flange is folded. 
     The seating member may connect the plurality of blades to each other and supports the plurality of blades in a circumferential direction. 
     The plurality of blades and the seating member may be integrally formed. 
     The seating member may be formed in a ring shape and detachable from the plurality of blades. 
     The seating flange may include a seating rib formed such that an end portion of the seating flange is bent so as to be in contact with the flange shaft. 
     The seating flange may form a separation space with an outer circumferential surface of the pulsator to be disposed to face the outer circumferential surface of the pulsator. 
     The drum rear surface may include a first drum rear surface extended from the cylindrical portion, and a second drum rear surface protruded from the first drum rear surface toward the front side of the drum to be connected to the seating flange, the second drum rear surface disposed in parallel with the front surface of the pulsator. 
     The flange shaft may include a flange protrusion protruded toward a rear surface of the pulsator, and the pulsator comprises a pulsator groove configured to allow the flange protrusion to be inserted thereto. 
     The flange protrusion and the pulsator groove may be formed in a circular shape. 
     In accordance with another aspect of the present disclosure, a washing machine may include a cabinet, a tub provided in the cabinet to store washing water, a drum having a cylindrical portion and a rear cover provided in one side of the cylindrical portion and configured to be rotatably provided in the tub, a pulsator configured to be rotatable independently of the drum and configured to be surrounded by an inner circumferential surface of the rear cover and a flange shaft coupled to the drum to transmit a rotational force to the drum in the rear side of the pulsator and configured to allow the rear cover to be inserted thereinto. 
     The rear cover may include a drum rear surface configured to form a rear surface of the drum, and a seating flange bent from the drum rear surface to be inserted into the flange shaft. 
     The flange shaft may include a flange body coupled to a shaft configured to transmit power from a drive device, a plurality of blades extended radially from the flange body, and a seating member configured to connect the plurality of blades to each other. The seating flange may be seated in at least one of the plurality of blades and the seating member. 
     The flange shaft may include a seating groove formed in at least one of the plurality of blades and the seating member and configured to allow the seating flange to be inserted thereto. 
     In accordance with still another aspect of the present disclosure, a washing machine may include a cabinet, a tub provided in the cabinet to store washing water, a drum configured to be rotatably provided in the tub with respect to a rotation shaft, and provided with a cylindrical portion, and a rear cover provided in the rear side of the cylindrical portion and extended toward the rotation shaft, a pulsator configured to be rotatable independently of the drum in the drum and disposed in the inner side of the rear cover and a flange shaft provided with a seating groove to which rear cover is inserted, and configured to transmit a rotational force to the drum. 
     Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like. 
     Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: 
         FIG. 1  is a perspective view illustrating a washing machine in accordance with an embodiment of the present disclosure; 
         FIG. 2  is a cross-sectional view illustrating the washing machine in accordance with an embodiment of the present disclosure; 
         FIG. 3  is a perspective view illustrating a part of the washing machine in accordance with an embodiment of the present disclosure; 
         FIG. 4  is an exploded-perspective view illustrating a part of the washing machine in accordance with an embodiment; 
         FIG. 5  is a front view illustrating a flange shaft of the washing machine in accordance with an embodiment; 
         FIG. 6  is a side view illustrating the flange shaft of the washing machine in accordance with an embodiment; 
         FIG. 7  is an enlarged view illustrating A of  FIG. 2 ; 
         FIG. 8  is a cross-sectional view illustrating a part of the washing machine in accordance with another embodiment; 
         FIG. 9  is an exploded-perspective view illustrating a part of a washing machine in accordance with another embodiment; 
         FIG. 10  is a view illustrating a flange shaft of the washing machine in accordance with another embodiment; 
         FIG. 11  is a view illustrating coupling of a drum, the flange shaft, and a pulsator of the washing machine in accordance with another embodiment; 
         FIG. 12  is an enlarged view illustrating B of  FIG. 11 . 
         FIG. 13  is an exploded-perspective view illustrating a part of a washing machine in accordance with another embodiment; 
         FIGS. 14 and 15  are views illustrating a flange shaft of the washing machine in accordance with another embodiment; 
         FIG. 16  is a view illustrating coupling of a drum, the flange shaft, and a pulsator of the washing machine in accordance with another embodiment; 
         FIG. 17  is an enlarged view illustrating C of  FIG. 16 , and 
         FIG. 18  is an enlarged view illustrating D of  FIG. 16 . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 through 18 , discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device. 
     In addition, the same reference numerals or signs shown in the drawings of the present 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 present 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 present 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, 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 present 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 present disclosure will be described more fully hereinafter with reference to the accompanying drawings. 
       FIG. 1  is a perspective view illustrating a washing machine in accordance with an embodiment of the present disclosure,  FIG. 2  is a cross-sectional view illustrating the washing machine in accordance with an embodiment of the present disclosure, and  FIG. 3  is a perspective view illustrating a part of the washing machine in accordance with an embodiment of the present disclosure. 
     A washing machine  1  includes a cabinet  10  forming a washing space therein, a tub  20  accommodating washing water or rinse water to be used for washing or rinsing cycle, and a drive device  80  rotating a drum  130 . The washing space in the cabinet may be formed by the tub  20  and the drum  130 . 
     The cabinet  10  is provided with a control panel  79  including an input  77   a  and  77   b  configured to receive an operation command of the washing machine  1  from a user and a display  78  configured to display operation information of the washing machine  1 . 
     The input  77   a  and  77   b  receives commands from the user related to the operation of the washing machine  1  such as a washing time, the number of rinsing times, a spin-dry time, a drying time, an operation and a pause, and the input  77   a  and  77   b  may employ a pressure type button  77   a  and a rotation type button  77   b . The display  78  may display information related to the operation of the washing machine  1  such as an amount of washing water, a cycle that is currently operated, and a period of time that is a remaining time until the washing is completed. The display  78  may employ a Liquid Crystal Display (LCD) panel, or a Light Emitting Diode (LED) panel. 
     According to an embodiment, in the washing machine  1 , the input  77   a  and  77   b , and the display  78  are separately provided, but is not limited thereto. When the washing machine  1  employs a Touch Screen Panel (TSP), an input and a display may be integrally provided. 
     The cabinet  10  includes frames  10   a ,  10   b ,  10   c , and  10   d . The frames  10   a ,  10   b ,  10   c  and  10   d  are formed of an upper frame  10   a  forming an upper surface of the cabinet, a front frame  10   b  and a rear frame  10   c  forming a front and a rear surface of the cabinet  10 , and a side frame  10   d  and a bottom frame connecting the front frame  10   b  to the rear frame  10   c  and forming a side surface and a bottom surface of the cabinet  10 . 
     A first opening  2   a  is formed in the front frame  10   b  of the cabinet  10  to allow laundry to be put into the drum  130 . The first opening  2   a  may be opened and closed by a door assembly  60  installed in the front frame  10   b  of the cabinet  10 . 
     A diaphragm  45  may connect the cabinet  10  to the tub  20 . Particularly, the diaphragm  45  may be disposed between the first opening  2   a  of the cabinet  10  and an opening  21  of the tub  20  corresponding to the first opening  2   a . The diaphragm  45  forms a passage from the first opening  2   a  of the cabinet  10  to the opening  21  of the tub  20 . The diaphragm  45  may reduce a vibration that is transmitted to the front frame  10   b  upon the rotation of the drum  130 . 
     The diaphragm  45  may be formed of an injection material molded by a thermoplastic elastomer. Since the thermoplastic elastomer has the elasticity like rubber at room temperature, the diaphragm  45  formed of the thermoplastic elastomer may effectively attenuate vibration transmitted from the tub  20  to the front frame of the cabinet  10 . 
     Between the tub  20  and the cabinet  10 , a spring  17  may be provided to support the tub  20  from the upper side. By using the elastic force of the spring  17 , the spring  17  serves to mitigate vibrations and noise caused by the movement of the tub  20 . 
     A water supply pipe  13  supplying washing water to the tub  20  is installed at an upper portion of the tub  20 . A water supply valve  14  is provided at one side of the water supply pipe  13 . 
     A detergent supply device  40  is connected to the tub  20  via a connection pipe  16 . Water supplied through the water supply pipe  13  is supplied to the inside of the tub  20  together with the detergent by passing through the detergent supply device  40 . 
     The tub  20  is supported by a damper  42 . The damper  42  connects an inner bottom surface of the cabinet  10  to an outer surface of the tub  20 . In addition, as well as the inner bottom surface, the damper  42  may be positioned on the upper side, left side, and right side of the cabinet  10  so as to support the tub  20 . The damper  42  or the spring  17  may mitigate the vibrations and the shocks caused by the vertical movement of the tub  20  in the upper and lower portions of the tub  20 . The tub  20  may be supported by at least one damper  42 . 
     A drain pump  4  configured to discharge the water inside the tub  20  to the outside of the cabinet  10 , a connection hose  5  configured to connect the tub  20  to the drain pump  4  to allow the water in the tub  20  to flow into the drain pump  4 , and a drain hose  5  configured to guide water, which is pumped by the drain pump  4 , to the outside of the cabinet  10  may be provided in a lower portion of the  20 . 
     The door assembly  60  is configured to open and close the first opening  2   a.    
     The door assembly  60  may include a door portion  62  provided to correspond to the first opening  2   a  and an auxiliary door  68  rotatably provided in the door portion  62 . 
     The door portion  62  may be rotatable with respect to the cabinet  10 . The door portion  62  may include a door body  64  and a door glass  65 . 
     The door body  64  may be provided to form a frame of the door portion  62 . In other words, the door body  64  may be provided to correspond to the first opening  2   a . When the door body  64  is rotated about the cabinet  10 , the door assembly  60  may open and close the first opening  2   a . Therefore, the door body  64  may be formed to correspond to the shape of the first opening  2   a . According to the embodiment, since the first opening  2   a  is formed in an approximately circular shape, the door body  64  may be formed in a circular shape or a ring shape. 
     The door portion  62  may include a second opening  66 . The second opening  66  may be formed in the door body  64 , but is not limited thereto. Alternatively, the second opening  66  may be formed in the door glass  65 . The second opening  66  may be opened and closed by an auxiliary door  68  described later, which is performed independently of the first opening  2   a . Although the first opening  2   a  is closed by the door assembly  60 , the second opening  66  may be opened by the auxiliary door  68  so that a user additionally inputs the detergent or laundry to the inside of the washing machine. That is, the second opening  66  may be connected to the inside of the cabinet  10  or the inside of the drum  130 . 
     The door portion  62  may include the door glass  65 . 
     The door glass  65  may be formed of a transparent material so that the inside of the drum  130  can be seen from the outside of the washing machine even when the door assembly  60  is in the closed position. The door glass  65  may be arranged to protrude convexly from the door body  64 . With such a configuration, when the door assembly  60  is in the closed position, the door glass  65  may be provided to be more inserted into the cabinet  10  than the first opening  2   a.    
     The drum  130  may have a substantially cylindrical shape having a front surface opened and the drum  130  may be rotatably provided inside the tub  20 . That is, the drum  130  may include an opening formed in the front surface thereof. The drum  130  may be disposed such that a central axis thereof is parallel to a central axis of the tub  20 . 
     The drum  130  may rotate inside the tub  20 . The drum  130  may perform washing by lifting and lowering the laundry while the drum  130  rotates. A plurality of through holes  133   a  may be formed around the drum  130  to allow the washing water stored in the tub  20  to flow. In addition, at least one protrusion  133   b  protruding through the inside of the drum  130  may be provided around the drum  130 . When the laundry is washed, the protrusions  133   b  may rub the laundry to improve the washing performance. 
     In this embodiment, since the drum  130  is not provided with a lifter, the plurality of through holes  133   a  and/or protrusions  133   b  may be continuously formed along the circumferential surface of the drum  130 . That is, in the conventional washing machine, since a lifter for lifting the laundry is provided on a part of the inner circumferential surface of the drum  130 , a plurality of through holes cannot be continuously formed along the circumferential surface of the drum  130 . In other words, in the conventional washing machine, the through hole is not formed in a portion where the lifter is provided. Alternatively, in the case of the washing machine  1  according to the embodiment, since the plurality of through holes  133   a  and/or the protrusions  133   b  are continuously formed along the inner circumferential surface of the drum  130 , the washing space may be further secured and the washing water stored in the tub  20  may be further introduced into the drum  130 , so that the washing performance can be improved. 
     A pulsator  70  may be disposed in the inner side of the rear side of the drum  130  and rotatably installed with respect to the drum  130 . The pulsator  70  may be configured to be rotatable independently of the drum  130 . That is, the pulsator  70  may rotate in the same direction as the drum  130 , or may rotate in a different direction from the drum  130 . The rotation axis of pulsator  70  may be the same as the rotation axis of drum  130 . 
     The pulsator  70  may include a pulsator body  72  (refer to  FIG. 4 ) and at least one pulsator blade  74  (refer to  FIG. 4 ) formed in a front surface  72   a  of the pulsator body  72 . During the washing is performed, the pulsator may generate a water flow in the forward and backward directions inside the drum  130  through the pulsator blade  74 . According to an embodiment, it may be possible to improve the washing performance by the pulsator  70 . 
     A drive device  80  including a first drive device  81  configured to supply power to the pulsator  70  and a second drive device  91  configured to supply power to the drum  130  may be provided at the rear side of the tub  20 . 
     The first drive device  81  may include a first drive motor  82  configured to generate a rotational force to rotate the pulsator  70 , a first shaft  83  configured to be extended to the rear side from the pulsator  70  to become a rotation axis of the pulsator  70 , a first pulley  84  connected to the first shaft  83 , and a first belt  85  configured to connect the first drive motor  82  to the first pulley  84 . 
     The first drive motor  82  may be fixed to the outside of the tub  20  and supply power to the pulsator  70 . Particularly, the first drive motor  82  may be mounted on a part of the lower end portion of the outer circumferential surface of the tub  20 . 
     The first drive motor  82  may include a first motor shaft  86 , wherein the first motor shaft  86  may be configured to be more extended to the rear side of the washing machine  1  than a second motor shaft  96  of a second drive motor  92  described later. By using the above mentioned configuration, the first belt  85  may be arranged so as not to interfere with a second belt  95 . 
     The first drive motor  82  may be a motor capable of forward rotation and reverse rotation. Accordingly, the first drive motor  82  may selectively rotate the pulsator  70  in any one direction of the same direction as a rotation direction of the drum  130  and the opposite direction to the rotation direction of the drum  130 . The first drive motor  82  may be a brushless DC (BLDC) motor. 
     The first shaft  83  may be connected to a back surface of the pulsator  70  and extended from the pulsator  70  along the rotation axis of the pulsator  70 . That is, the first shaft  83  may be extended to the rear side of the pulsator  70 . The first shaft  83  may become the rotation axis of the pulsator  70 . The first shaft  83  may be formed separately from the pulsator  70  and then coupled to the pulsator  70 , but is not limited thereto. The first shaft  83  may be integrally formed with the pulsator  70 . 
     A first bearing  87  configured to rotatably support the first shaft  83  may be provided on the outer circumferential surface of the first shaft  83 . The first bearing  87  may be fixed to a second shaft  93 . 
     One end of the first shaft  83  may be connected to the pulsator  70  and the other end of the first shaft  83  may be connected to a first pulley  84  described later. By using the structure, the first shaft  83  may transmit the power, which is received from the first drive motor  82  by the first pulley  84 , to the pulsator  70  so as to rotate the pulsator  70 . 
     The first shaft  83  may be rotatably inserted into the second shaft  93 . Accordingly, the first shaft  83  may rotate in the same direction as the second shaft  93 , or may rotate in the opposite direction to the second shaft  93 . 
     Since the first shaft  83  is longer than the second shaft  93 , the first shaft  83  may be inserted into the second shaft  93  so as to protrude from both ends of the second shaft  93 . According to this configuration, the pulsator  70  connected to one end of the first shaft  83  may be disposed inside the drum  130  connected to one end of the second shaft  93 . The first pulley  84  connected to the other end of the first shaft  83  may be more spaced from the drum  130  than the second pulley  94  connected to the other end of the second shaft  93 . 
     The first pulley  84  may receive the power from the first drive motor  82  and transmit the power to the pulsator  70 . The first pulley  84  may be disposed to be more spaced from the drum  130  than a second pulley  94  described below. 
     The first belt  85  may connect the first drive motor  82  and the first pulley  84  to transmit the power of the first drive motor  82  to the first pulley  84 . Particularly, the inner surface of the first belt  85  may be brought into contact with and coupled to the first motor shaft  86  of the first drive motor  82  and the first pulley  84 . That is, the rotational movement of the first belt  85  may be guided by the first motor shaft  86  of the first drive motor  82  and the first pulley  84 . 
     The first belt  85  may be spaced apart from the second belt  95  by a predetermined distance (d). Accordingly, the second belt  95  may not be interfered with the first belt  85 . 
     The second drive device  91  may include a second drive motor  92  configured to generate a rotational force to rotate the drum  130 , a second shaft  92  configured to be extended to the rear side from the drum  130  to become a rotation axis of the drum  130 , a second pulley  94  connected to the second shaft  93 , and a second belt  95  configured to connect the second drive motor  92  to the second pulley  94 . 
     The second drive motor  92  may be fixed to the outside of the tub  20  and supply the power to the drum  130 . Particularly, the second drive motor  92  may be mounted on a part, which is different from a part of the lower end portion of the outer circumferential surface of the tub  20  to which the first drive motor  82  is fixed. 
     The second drive motor  92  may include a second motor shaft  96 , wherein the second motor shaft  96  may be configured to be less extended to the rear side of the cabinet  10  than the first motor shaft  86  of the first drive motor  82 . By using the above mentioned configuration, the second belt  95  may be arranged so as not to interfere with the first belt  85 . 
     The second drive motor  92  may be a motor capable of forward rotation and reverse rotation. Accordingly, the second drive motor  92  may rotate the drum  130  in a first direction or a second direction different from the first direction. The second drive motor  92  may be a brushless DC (BLDC) motor that is the same as the first drive motor  82 . 
     According to the embodiment, the second drive motor  92  may be a drive motor the same as the first drive motor  82 . Particularly, the second drive motor  92  may be configured to have a driving force the same as the driving force of the first drive motor  82 . 
     The second shaft  93  may be connected to a rear surface of the drum  130  and extended from the drum  130  along the rotation axis of the drum  130 . That is, the second shaft  93  may be extended to the rear side of the drum  130 . The second shaft  93  may become the rotation axis of the drum  130 . The second shaft  93  may penetrate the rear plate of the tub  20  and then connect the drum  130  to the second pulley  94 . The second shaft  93  may be formed separately from the drum  130  and then coupled to the drum  130 , but is not limited thereto. Alternatively, the second shaft  93  may be integrally formed with the drum  130 . 
     Particularly, the second shaft  93  may be coupled to a flange shaft  100  provided on the rear surface of the drum  130 . The flange shaft  100  may be connected to the second shaft  93 . The flange shaft  100  may rotate together with the rotation of the second shaft  93 . The flange shaft  100  may be configured to be extended radially from the second shaft  93 . The flange shaft  100  may be coupled to one side of the drum  130  and thus the rotational force of the second shaft may be transmitted to the drum  130  so that the drum  130  rotates. 
     A second bearing  97  configured to rotatably support the second shaft  93  may be provided on the outer circumferential surface of the second shaft  93 . The second bearing  97  may be fixed to the tub  20 . 
     One end of the second shaft  93  may be connected to the drum  130  and the other end of the second shaft  93  may be connected to the second pulley  94  described later. According to the configuration, the second shaft  93  may transmit the power received from the second drive motor  92  to the drum  130  so as to rotate the drum  130 . 
     In addition, the second shaft  93  may have a hollow therein so that the first shaft  83  is rotatably inserted therein. Particularly, the hollow of the second shaft  93  may be formed to have a certain diameter, which is larger than a diameter of the first shaft  83  by a predetermined size, so that the first shaft  83  can be inserted into the hollow of the second shaft  93  and rotate. According to this configuration, the second shaft  93  may rotate in the same direction as the first shaft  83 , or may rotate in the opposite direction to the first shaft  83 . 
     The second shaft  93  may be shorter than the first shaft  83  so that the first shaft  83  protrudes from both ends of the second shaft  93 . According to this configuration, the rear plate of the drum  130  connected to one end of the second shaft  93  may be disposed in more rear side than the pulsator  70  connected to one end of the first shaft  83 , and the second pulley  94  connected to the other end of the second shaft  93  may be disposed closer to the drum  130  than the first pulley  84  connected to the other end of the first shaft  83 . 
     The second pulley  94  may receive the power from the second drive motor  92  and transmit the power to the drum  130 . The second pulley  94  may be disposed closer to the drum  130  than the first pulley  84 . 
     The second belt  95  may connect the second drive motor  92  and the second pulley  94  to transmit the power of the second drive motor  92  to the second pulley  94 . Particularly, the inner surface of the second belt  95  may be brought into contact with and coupled to the second motor shaft  96  of the second drive motor  92  and the second pulley  94 . That is, the rotational movement of the second belt  95  may be guided by the second motor shaft  96  of the second drive motor  92  and the second pulley  94 . 
     The second belt  95  may be spaced apart from the first belt  85  by a predetermined distance (d). Accordingly, the second belt  95  may not be interfered with the first belt  85 . 
       FIG. 4  is an exploded-perspective view illustrating a part of the washing machine in accordance with an embodiment,  FIG. 5  is a front view illustrating a flange shaft of the washing machine in accordance with an embodiment,  FIG. 6  is a side view illustrating the flange shaft of the washing machine in accordance with an embodiment, and  FIG. 7  is an enlarged view illustrating A of  FIG. 2 . 
     The drum  130  may be rotatably provided inside the tub  20 . The drum  130  may be configured such that its center of rotation coincides with the center of rotation of the tub  20 . The drum  130  may include a cylindrical portion  132  and a rear cover  134 . 
     The cylindrical portion  132  may be provided to form a side surface of the drum  130 . The cylindrical portion  132  may be provided with a plurality of through holes  133   a  and/or protrusions  133   b  as described above. 
     The rear cover  134  may be provided on one side of the cylindrical portion  132 . The rear cover  134  may form the rear surface of the drum  130 . The rear cover  134  may be provided at the rear of the cylindrical portion  132  and extended toward the rotation axis. The rear cover  134  may be disposed along the circumference of the pulsator  70 . That is, the rear cover  134  is disposed apart from the radius of rotation of the pulsator  70 , so that interference between the pulsator  70  and the rear cover  134  can be prevented. The rear cover  134  may be configured to be seated in the flange shaft  100  supporting the drum  130 . That is, the rear cover  134  may be coupled to the flange shaft  100 . 
     The flange shaft  100  may include a flange body  110  and a plurality of blades  112 . The flange body  110  may be coupled to the second shaft  93 . The flange body  110  may be integrally formed with the second shaft  93 . A plurality of blades  112  may be formed to be extended radially from the flange body  110 . In this embodiment, the plurality of blades  112  is provided such that three blades  112  are spaced apart at equal intervals. However, the number or the arrangement of the plurality of blades  112  is not limited thereto. 
     The plurality of blades  112  may include a coupling portion  113  formed in an end portion of the blade to be coupled to the drum  130 . The coupling portion  113  may be coupled to the drum  130  through a screw connection. Particularly, the coupling portion  113  may be coupled to the cylindrical portion  132  of the drum  130 . However, the coupling method of the coupling part  113  and the drum  130  is not limited thereto. 
     When the second shaft  93  is rotated by the drive device  80 , a rotational force may be transmitted to the flange shaft  100  coupled to the second shaft  93  and then the rotational force may be transmitted to the drum  130  connected to the flange shaft  100 . 
     The flange shaft  100  may include a seating member  114 . 
     The seating member  114  is provided to connect the plurality of blades  112  to each other. The seating member  114  may be formed in a substantially ring shape. Since the seating member  114  is provided to connect the plurality of blades  112  to each other, the seating member  114  may support the plurality of blades  112  in the circumferential direction. That is, the seating member  114  may stably support the plurality of blades  112  in the circumferential direction. In this embodiment, the plurality of blades  112  and the seating member  114  are integrally formed, but is not limited thereto. Alternatively, the seating member  114  may be configured to be detachable from the plurality of blades  112 . The flange shaft  100  may further include a connecting member  115 . The connecting member  115  may be extended radially from the flange body  110  and may connect the flange body  110  to the seating member  114 . The connecting member  115  may stably support the seating member  114 . 
     The flange shaft  100  may include a seating groove  116 . 
     The seating groove  116  may be configured to allow one side of the above-described rear cover  134  to be seated. The seating groove  116  may be formed in at least one of the plurality of blades  112  and the seating member  114 . The seating groove  116  may include first and second seating grooves  116   a  and  116   b . The first seating groove  116   a  may be formed in the plurality of blades  112  and the second seating groove  116   b  may be formed in the seating member  114 . The first and second seating grooves  116   a  and  116   b  may be formed in a circular shape with respect to the center of rotation of the drum  130 . 
     The rear cover  134  may include a drum rear surface  136  and a seating flange  138 . 
     The drum rear surface  136  may be provided to be extended from the cylindrical portion  132  of the drum  130  toward the pulsator  70 . The drum rear surface  136  together with the pulsator  70  may form the rear face of the drum  130 . The drum rear surface  136  may be formed around the pulsator  70 . 
     The drum rear surface  136  may include a first drum rear surface  136   a  extended from the cylinder and a second drum rear surface  136   b  bent from the first drum rear surface  136   a . The second drum rear surface  136   b  may be extended from the first drum rear surface  136   a  to protrude toward the inside of the drum  130 . The seating flange  138  may be extended from the second drum rear surface  136   b . The second drum rear surface  136   b  may protrude from the rear surface of the drum  130  to have a height corresponding to the front surface  72   a  of the pulsator  70 . The second drum rear surface  136   b  may be disposed in parallel to the front surface  72   a  of the pulsator  70 . That is, the second drum rear surface  136   b  and the front surface  72   a  of the pulsator  70  may be formed to prevent a step portion. With this configuration, it is possible to prevent the laundry from being caught between the pulsator  70  and the rear cover  134 . In addition, the first and second drum rear surfaces  136   a  and  136   b  are formed to be inclined so that the force applied to the rear cover  134  by laundry or the like may be dispersed. 
     The seating flange  138  may be bent from the drum rear surface  136  and then seated in the flange shaft  100 . The seating flange  138  may be bent rearward from the drum rear surface  136 . The seating flange  138  may be formed in an approximately ring-shape. 
     The inner surface of the seating flange  138  may be formed to face the radial outer circumferential surface of the pulsator  70 . When a space between an inner surface of the seating flange  138  and an outer circumferential surface of the pulsator  70  is referred to as a separation space (S), the separation space (S) may become an minimum interval to prevent the laundry from being introduced thereinto while the pulsator  70  is not interfered with the seating flange  138  when the pulsator  70  rotates. 
     The seating flange  138  may include an insertion rib  138   a.    
     The insertion rib  138   a  may be formed at the end of the seating flange  138 , and the insertion rib  138   a  may be configured to be inserted into the seating groove  116  of the flange shaft  100 . The seating groove  116  may be formed in an approximately circular shape, and the insertion rib  138   a  may be formed in an approximately ring shape by corresponding to the shape of the seating groove  116 . 
     The insertion rib  138   a  may be configured to have a greater thickness than the seating flange  138 . With this configuration, the insertion rib  138   a  may be firmly inserted and fixed in the seating groove  116 . For example, the insertion rib  138   a  may be formed in a hemming structure at an end portion of the seating flange  138 . That is, the insertion rib  138   a  may be formed such that an end portion of the seating flange  138  is overlapped by being folded by 180 degree. 
     Since the rear cover  134  may be positioned in the radial direction from the outer circumferential surface of the pulsator  70 , the pulsator  70  may be not interfered with the rear cover  134  even though the pulsator  70  is rotated in a direction different from the drum  130 . In addition, the rear cover  134  may disperse the force, which is applied to the rear cover  134  by the laundry upon the washing, to the cylindrical portion  132  or the flange shaft  100  so as to prevent the deformation. 
     The flange shaft  100  may include a flange protrusion  118 . 
     The flange protrusion  118  may protrude toward the rear side of the pulsator  70 . The pulsator  70  may include a pulsator groove  76  in which the flange protrusion  118  is inserted into the rear surface of the pulsator  70 . When the pulsator  70  and the drum  130  are installed with respect to the same rotation axis, the flange protrusion  118  may be inserted into the pulsator groove  76 . The flange protrusion  118  and the pulsator groove  76  may prevent the foreign material or the laundry inside the drum  130  from entering into the rear side of the pulsator  70 . The flange protrusion  118  may be spaced apart from the inner surface of the pulsator groove  76  by a predetermined distance so that the rotation of the pulsator  70  is not interfered with the flange protrusion  118 . 
     Hereinafter a washing machine according to another embodiment will be described. 
     In the following description, a description of the same components as those of the above mentioned configuration will be omitted. 
       FIG. 8  is a cross-sectional view illustrating a part of the washing machine in accordance with another embodiment. 
     A rear cover  234  may include a drum rear surface  136  and a seating flange  238 . 
     The seating flange  238  may be bent from the drum rear surface  136  and then seated in a flange shaft  100 . The seating flange  238  may be bent rearward from the drum rear surface  136 . The seating flange  238  may be formed in an approximately ring-shape. 
     An inner surface of the seating flange  238  may be formed to face the radial outer circumferential surface of the pulsator  70 . When a space between an inner surface of the seating flange  238  and an outer circumferential surface of the pulsator  70  is referred to as a separation space (S), the separation space (S) may be an minimum interval to prevent the laundry from being introduced thereinto while the pulsator  70  is not interfered with the seating flange  238  when the pulsator  70  rotates. 
     The seating flange  238  may include a seating rib  238   a.    
     The seating rib  238   a  may be formed at the end of the seating flange  238 , and the seating rib  238   a  may be bent from a body portion of the seating flange  238 . According to an embodiment, the seating rib  238   a  may be bent from the body portion of the seating flange  238  in a rotation center direction of the drum  130 , but is not limited thereto. Alternatively, the seating rib  238   a  may be bent in a radial direction from the center of the rotation. 
     The seating rib  238   a  may be in contact with or be fixed to the flange shaft  100 . The seating rib may be formed in a substantially ring-shape. Force applied to the rear cover  234  may be distributed over the contact area between the seating rib  238   a  and the flange shaft  100 , and thus it is possible to improve the durability of the rear cover  234 . 
     Hereinafter a washing machine according to another embodiment will be described. 
     In the following description, a description of the same components as those of the above mentioned configuration will be omitted. 
       FIG. 9  is an exploded-perspective view illustrating a part of a washing machine in accordance with another embodiment,  FIG. 10  is a view illustrating a flange shaft of the washing machine in accordance with another embodiment,  FIG. 11  is a view illustrating coupling of a drum, the flange shaft, and a pulsator of the washing machine in accordance with another embodiment, and  FIG. 12  is an enlarged view illustrating B of  FIG. 11 . 
     A flange shaft  300  may include a flange body  310 , and a plurality of blades  312 . 
     The plurality of blades  312  may include a coupling portion  313  formed in an end portion of the blade to be coupled to the drum  130 . The coupling portion  313  may be coupled to the drum  130  by using a screw, but the coupling method of coupling portion  313  and the drum  130  is not limited thereto 
     The flange shaft  300  may include a seating groove  316 . 
     The seating groove  316  may allow one side of the rear cover  134  to be seated thereon. The seating groove  316  may be formed in the plurality of blades  312 . An insertion rib  138   a  of the rear cover  134  may be inserted into the seating groove  316  formed in a plurality of blades  312  so that the rear cover  134  is firmly fixed. The flange shaft  300  may include a flange protrusion  318 . 
     Hereinafter a washing machine according to another embodiment will be described. 
     In the following description, a description of the same components as those of the above mentioned configuration will be omitted. 
       FIG. 13  is an exploded-perspective view illustrating a part of a washing machine in accordance with another embodiment,  FIGS. 14 and 15  are views illustrating a flange shaft of the washing machine in accordance with another embodiment,  FIG. 16  is a view illustrating coupling of a drum, the flange shaft, and a pulsator of the washing machine in accordance with another embodiment,  FIG. 17  is an enlarged view illustrating C of  FIG. 16 , and  FIG. 18  is an enlarged view illustrating D of  FIG. 16 . 
     A flange shaft  400  may include a flange body  410 , a plurality of blades  412  and a seating member  414 . A plurality of blades  412  may include a coupling portion  413  formed in an end portion of the blade and coupled to the drum  130 . 
     The seating member  414  is provided to connect the plurality of blades  412  to each other. The seating member  414  may be formed in a substantially ring shape. Since the seating member  414  is provided to connect the plurality of blades  412  to each other, the seating member  414  may support the plurality of blades  412  in the circumferential direction. That is, the seating member  414  may stably support the plurality of blades  412  in the circumferential direction. The seating member  414  may be configured to be detachable from the plurality of blades  412 . The seating member  414  may be fixed to the plurality of blades  412  through a screw, or alternatively, the seating member  414  may be fixed to the plurality of blades  412  through a separate member. The seating member  414  may form a coupling groove  414   a  to which the plurality of blades  412  is coupled. The plurality of blades  412  may be inserted and coupled to the coupling groove  414   a  and thus a first and second seating groove  416   a  and  416   b  may be positioned at the same height. However, the coupling method of the seating member  414  is not limited thereto. 
     The flange shaft  400  may include a seating groove  416 . 
     The seating groove  416  may be configured to allow one side of the rear cover  134  to be seated. The seating groove  416  may include a first and second seating groove  416   a  and  416   b . The first seating groove  416   a  may be formed in the plurality of blades  412  and the second seating groove  416   b  may be formed in the seating member  414 . The first and second seating grooves  416   a  and  416   b  may be formed in a circular shape. 
     The flange shaft  400  may include a flange protrusion  418 . 
     The flange protrusion  418  may protrude toward the rear side of the pulsator  70 . The pulsator  70  may include a pulsator groove  76  in which the flange protrusion  418  is inserted into the rear surface thereof. When the pulsator  70  and the drum  130  are installed with respect to the same rotation axis, the flange protrusion  418  may be inserted into the pulsator groove  76 . The flange protrusion  418  and the pulsator groove  76  may prevent the foreign material or the laundry inside the drum  130  from entering into the rear side of the pulsator  70 . The flange protrusion  418  may be spaced apart from the inner surface of the pulsator groove  76  by a predetermined distance so that the rotation of the pulsator  70  is not interfered with the flange protrusion  418 . The flange protrusion  418  may include a first flange protrusion  418   a  formed in the plurality of blades  412  and a second flange protrusion  418   b  formed in the seating member  414 . 
     As is apparent from the above description, it may be possible to improve the washing efficiency by applying a pulsator structure to a drum type washing machine. 
     It may be possible to stably support the rotation of a drum by improving a coupling structure between the drum and a flange shaft. 
     It may be possible to prevent the rotation of the drum and the rotation pulsator from being interfered with each other. 
     It may be possible to prevent the deformation of the drum caused by the impact upon the rotation of the laundry in the drum. 
     It may be possible to prevent the laundry from being caught between the pulsator and the drum when the drum is rotated. 
     Although a few embodiments of the present 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. 
     Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.