Patent Publication Number: US-2018044836-A1

Title: Clothes treating apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a laundry treating apparatus and a method of controlling the same. 
     BACKGROUND ART 
     A conventional laundry treating apparatus includes a cabinet forming an external appearance, a tub provided inside the cabinet, a drum rotatably provided inside the tub to wash laundry, and a motor of which rotary shaft is fixed to the drum by passing through the tub to rotate the drum. 
     The drum may be rotated without maintaining dynamic equilibrium depending on a position of laundry stored therein. 
     Dynamic equilibrium means ‘the state that a centrifugal force or a moment made by the centrifugal force is 0 with respect to a rotary shaft when a rotor is rotated’. In case of a rigid body, if mass distribution of the rigid body is uniformly maintained around the rotary shaft, dynamic equilibrium is maintained. 
     Therefore, dynamic equilibrium in the laundry treating apparatus may be understood that mass distribution of laundry is within an allowable range around the rotary shaft of the drum when the drum is rotated in a state that laundry is stored in the drum (the case that the drum is rotated while being vibrated within the allowable range). 
     In contrast, the state that dynamic equilibrium has been broken (i.e., unbalance) in the laundry treating apparatus means that mass distribution is not maintained uniformly around the rotary shaft of the drum when the drum is rotated. This unbalance is generated when laundry is not distributed uniformly inside the drum. 
     If the drum of the unbalance state is rotated, the drum is vibrated, and the vibration of the drum is delivered to the tub or the cabinet, whereby noise may be caused. 
     The conventional laundry treating apparatus includes balancing units to solve unbalance of the drum. The balancing units provided in the conventional laundry treating apparatus are ball balancers or fluid balancers having a ball or a fluid received in a housing fixed to the drum. 
     The ball balancer or the fluid balancer included in the conventional laundry treating apparatus functions to control unbalance by moving the ball or the fluid to an opposite side of a direction where laundry causing unbalance is located when a rotation track of the drum wobbles by means of the laundry causing unbalance. 
     However, the aforementioned unbalance control is useful for a steady state that vibration of the drum is within a certain range, whereas a problem occurs in that the unbalance control is not effective at a transient vibration state of the drum. Also, the conventional balancing unit has a structure that it is difficult to immediately solve unbalance (actively solve unbalance) when unbalance is generated. 
     DISCLOSURE 
     Technical Problem 
     An object of the present invention is to provide a laundry treating apparatus that may solve unbalance by supplying water to balancers while a drum is being rotated without stopping its rotation in an unbalance state that laundry is not distributed uniformly. 
     Another object of the present invention is to provide a laundry treating apparatus that includes a structure for discharging water supplied to balancers of a drum after solving unbalance. 
     Still another object of the present invention is to provide a laundry treating apparatus that includes balancers for actively solving unbalance by supplying water thereto at upper and lower portions of a drum while the drum is being rotated. 
     Further still another object of the present invention is to provide a laundry treating apparatus that includes at least one balancer provided at an upper portion or a lower portion of a drum to actively solve unbalance by supplying water thereto while the drum is being rotated. 
     Technical Solution 
     To achieve these objects and other advantages and in accordance with the purpose of the invention, the present invention provides a laundry treating apparatus comprising a cabinet forming an external appearance and including a door provided on a top surface to take or put laundry out of or into the top surface; a tub provided inside the cabinet to store washing water therein; a drum rotatably provided inside the tub to receive the laundry therein; a balancer provided in a single body to be rotated together with the drum and provided to maintain dynamic equilibrium of the drum by supplying water thereinto; and a water supply unit supplying water to the balancer, wherein the balancer includes a drainage unit provided to drain the water received in the balancer when a rotating speed of the drum reaches a predetermined speed or less. 
     Also, the balancer is provided on at least one of an upper portion and a lower portion of the drum. 
     Also, the balancer includes a housing in which water is stored, at least one or more barriers partitioning the inside of the housing, and an inlet provided in the housing to allow the water to enter the inside of the housing. 
     Also, the drainage unit is provided at a circumferential inner side of the housing to drain the water inside the housing when the rotating speed of the drum reaches a predetermined speed or less. 
     Also, the barriers include a main barrier provided to partition the inside of the housing, and at least one or more sub barriers provided in a space partitioned by the main barrier to prevent the water received in the housing from being concentrated on one side. 
     Also, the sub barriers are provided to have their respective heights which gradually become higher along a rotating direction of the drum. 
     Also, the water supply unit includes a water supply nozzle provided to spray water to a desired position in a state that the balancer is rotated, and a water supply guider guiding the water sprayed by the water supply nozzle to enter the inside of the balancer. 
     Also, the water supply nozzle is provided to be communicated with a washing water supply unit for supplying washing water to the tub. 
     Also, the laundry treating apparatus further comprises a fluid balancer or a ball balancer provided at an upper portion or lower portion of the drum, having a fluid or a ball therein to maintain dynamic equilibrium of the drum. 
     Also, the drum is provided such that its rotary shaft is vertical to a lower surface of the cabinet. 
     Also, each of the drum and the tub includes an opening on an upper surface to put or take laundry into or out of the upper surface. 
     Also, the drainage unit is provided to drain the water received in the balancer in a direction vertical to a gravity direction. 
     Also, the barrier is extended in a direction vertical to a gravity direction to partition the inside of the housing. 
     Also, the laundry treating apparatus may further comprise a driving unit for rotating the drum. The driving unit includes a motor providing a rotating force, a shaft having one end communicated with the motor and the other end communicated with the drum, wherein the shaft is provided in parallel with a gravity direction. 
     Advantageous Effects 
     According to the present invention, it is possible to solve unbalance by supplying water to balancers while a drum is being rotated without stopping its rotation in an unbalance state that laundry is not distributed uniformly. 
     Also, according to the present invention, since a laundry treating apparatus includes a structure for discharging water supplied to balancers of a drum after solving unbalance, the water supplied to the balancers may be discharged efficiently. 
     Also, according to the present invention, it is possible to actively solve unbalance by supplying water balancers at upper and lower portions of a drum while the drum is being rotated. 
     Also, according to the present invention, since a laundry treating apparatus includes at least one balancer provided at an upper portion or a lower portion of a drum to supply water thereto while the drum is being rotated, unbalance may be solved more efficiently. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example of a laundry treating apparatus according to the present invention. 
         FIG. 2  illustrates an example of a sensor unit provided in the present invention. 
         FIG. 3  illustrates an example of an upper balancer provided in the present invention. 
         FIGS. 4, 5 and 6  illustrate an example of a lower balancer provided in the present invention. 
         FIG. 7  illustrates an example of a method for controlling unbalance generated in a laundry treating apparatus of the present invention. 
         FIG. 8  is a flow chart illustrating an example of a control method for determining a water supply amount and a water supply position of water supplied to an upper balancer and a lower balancer provided in a laundry treating apparatus of the present invention. 
         FIGS. 9 and 10  illustrate an example of water supply units provided in an upper balancer and a lower balancer to supply water. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Meanwhile, elements or control method of apparatuses which will be described below are only intended to describe the embodiments of the present invention and are not intended to restrict the scope of the present invention. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       FIG. 1  illustrates an example of a laundry treating apparatus according to the present invention. 
     Referring to  FIG. 1 , the laundry treating apparatus according to the present invention includes a cabinet  10  for forming an external appearance, a tub  20  provided inside the cabinet  10 , storing washing water therein, and a drum  30  rotatably provided inside the tub  20 , for receiving laundry therein. 
     Since the laundry treating apparatus of the present invention is a top loading type for putting or taking laundry into or out of a top surface, a rotary shaft of the drum  30  may be provided to be vertical to a lower surface of the cabinet  10 . 
     The cabinet  10  may include a cabinet opening  12  and a door  111  on the top surface of the cabinet  10 , wherein the cabinet opening  12  is provided to put or take laundry into or out of the top surface of the cabinet, and the door  11  is rotatably provided to open or close the cabinet opening  12 . 
     The tub  20  may include a tub opening  11  on a top surface thereof to put or take laundry into or out of the top surface. 
     Although not shown, the drum  30  may include a drum opening (not shown) for allowing laundry to be put into or taken out of the cabinet opening  12  and the tub opening  21 . 
     That is, a user may put laundry into the drum  30  sequentially through the cabinet opening  12 , the tub opening  21  and the drum opening (not shown) by opening the door  11  rotatably provided on the top surface of the cabinet  10 . 
     Also, the laundry treating apparatus of the present invention may include a water supply unit  70  for supplying water to the tub  20  and a drainage unit  60  for draining washing water from the tub  20 . 
     The water supply unit  70  may include a water supply hose  71  and a water supply valve  73 . One end of the water supply hose  71  may be protruded toward the outside of the cabinet  10  such that water may externally be supplied thereto, and the other end of the water supply hose  71  may be communicated with one side of the tub  20  such that the externally supplied water may be supplied to the tub  20 . The water supply valve  73  may be provided in the water supply hose  71  to control the amount of water supplied to the tub  20  through the water supply hose  71 . 
     The drainage unit  60  may include a drainage hose  61  and a drainage valve  63 . The drainage hose  61  has one end communicated with the tub  20  and the other end protruded to the outside of the cabinet  10 , whereby the washing water drained from the tub  20  may be discharged to the outside of the laundry treating apparatus. The drainage valve  63  may be provided in the drainage hose  61  to control the amount of the washing water discharged to the outside of the laundry treating apparatus through the drainage hose  61 . 
     The drum  30  is rotatably provided, and the laundry treating apparatus of the present invention may include a power unit  40  for rotating the drum  30 . 
     The power unit  40  may include a shaft  41  provided to be communicated with the drum  30  to deliver a rotational force generated in the power unit  40  to the drum  30 , a stator  45  for generating a rotating magnetic force for rotating the shaft  41 , a rotor  47  rotatably provided inside the stator  45  in a single body with the shaft  41 , and a bearing housing  43  provided to support gravity of the shaft  41  which is rotated. 
     The shaft  41  may be provided to be vertical to a lower surface of the cabinet  10 . 
     In other words, the shaft  41  may be provided in parallel with a gravity direction. 
     A BLDC motor typically used in the related art of the laundry treating apparatus may be used as the power unit  40  used in the laundry treating apparatus of the present invention. Since the BLDC motor is already known, its detailed description will be omitted. 
     Since the drum  30  is rotatably provided, vibration generated in the drum  30  may be delivered to the tub  20 , and the vibration delivered to the tub  20  may again delivered to the cabinet  10 . 
     If the tub  20  is vibrated, horizontal displacement or vertical displacement is generated. For this reason, interference between the tub  20  and the cabinet  10  is generated, whereby noise or damage may occur. 
     To avoid noise or damage, the laundry treating apparatus of the present invention may include a vibration unit for preventing vibration of the tub  20  from being delivered to the cabinet  10 . 
     The vibration unit may include a first holder  51  provided on one surface of the cabinet  10 , a second holder  53  provided on one surface of the tub  20 , a connector  55  connecting the first holder  51  with the second holder  53 , and an elastic member  57  provided at one end of the connector  55 , providing an elastic force to the second holder  53  and the connector  55 . 
     Also, the connector  55  may include a first clamp portion  551  provided at one end to prevent the connector  55  from being detached from the first holder  51 , and a second clamp portion  553  provided at the other end to prevent the connector  55  from being detached from the second holder  53 . 
     The drum  30  of the laundry treating apparatus according to the present invention may include balancers  31  and  32  on at least one of an upper portion or a lower portion of the drum  30  to prevent unbalance from being generated in the laundry stored in the drum  30  while the drum  30  is being rotated as described above. 
     As shown in  FIG. 1 , the upper balancer  31  may be provided on the upper portion of the drum  30 , and the lower balancer  32  may be provided on the lower portion of the drum  30 . 
     As described above, the conventional ball balancer or fluid balancer is provided to solve unbalance in such a manner that a ball or fluid moves passively in an opposite direction of a wobble direction of laundry stored in the drum  30  when the laundry wobbles. 
     However, the balancers  31  and  32  of the laundry treating apparatus according to the present invention may effectively solve unbalance even in a transient state as well as a steady state. 
     In more detail, the balancers  31  and  32  may be active balancers that identify a position where unbalance is generated by sensing a vibration state of the drum  30  or the tub  20  and then actively solve unbalance by supplying water in an opposite direction of the position where unbalance is generated. 
     However, if the active balancers  31  and  32  are provided on the upper and lower portions of the drum  30 , it may act as load in view of the material cost and efficiency of production. Therefore, the active balancer  31  or  32  may be provided on at least one of the upper and lower portions of the drum  30 , and the conventional ball balancer or fluid balancer may be provided on the other portion. 
     Preferably, since it is more effective to solve unbalance that the aforementioned active balancers  31  and  32  are provided on the upper and lower portions of the drum  30 , the laundry treating apparatus of the present invention will be described on the assumption that the active balancers  31  and  32  are provided on the upper and lower portions of the drum  30 . 
     To solve unbalance in the laundry treating apparatus of the present invention, the vibration state of the tub  20  or the drum  30  should be sensed. To this end, the laundry treating apparatus may further include a sensor unit. 
     The sensor unit may include a top sensor  81  provided on the upper surface of the tub  20  to sense vertical vibration on the upper surface of the tub  20 , an upper sensor  83  provided on an upper portion of a side of the tub  20  to sense horizontal vibration at the upper portion of the side of the tub  20 , and a lower sensor  85  provided on a lower portion of the side of the tub  20  to sense horizontal vibration at the lower portion of the side of the tub  20 . 
     In more detail, the sensors used in the sensor unit may be provided as optical sensors. The top sensor  81 , the upper sensor  83  and the lower sensor  85  may respectively derive sinusoidal shaped profiles by sensing a vertical distance between the upper surface of the tub  20  and the upper surface of the cabinet  10 , a horizontal distance between the upper portion of the side of the tub  20  and the upper portion of the side of the cabinet  10 , and a horizontal distance between the lower portion of the side of the tub  20  and the lower portion of the side of the cabinet  10  in real time. 
     The controller (not shown) determines a portion of the drum  30  where laundry causing unbalance is concentrated on by modeling the profiles sensed by the respective sensors of the sensor unit, and sprays water to the positions of the upper balancer  31  and the lower balancer  32  to solve unbalance. 
       FIG. 2  illustrates an example of a sensor unit  80  provided in the present invention. 
     Referring to  FIG. 2( a ) , the laundry treating apparatus of the present invention may include a top sensor  81  provided on the upper surface of the tub  20  to measure a distance YC from the upper surface of the tub  20  to the upper surface of the cabinet  10 . 
     Referring to  FIG. 2( b ) , the laundry treating apparatus of the present invention may include an upper sensor  83  provided on the upper portion of the side of the tub  20  to measure a distance YT from the upper portion of the side of the tub  20  to the upper portion of the side of the cabinet  10 . 
     Referring to  FIG. 2( c ) , the laundry treating apparatus of the present invention may include a lower sensor  85  provided on the lower portion of the side of the tub  20  to measure a distance YB from the lower portion of the side of the tub  20  to the lower portion of the side of the cabinet  10 . 
     More preferably, the top sensor  81 , the upper sensor  83  and the lower sensor  85  are provided as optical sensors. 
     The top sensor  81  serves to sense vertical vibration of the tub  20 , and the upper sensor  83  and the lower sensor  85  serve to sense horizontal vibration of the tub  20 . 
     Basically, since the upper sensor  83  and the lower sensor  85  serve to sense horizontal vibration, there is no big problem in sensing the position of the laundry causing unbalance even though one of the two sensors is only provided. 
     However, if the laundry is located in the drum  30  in a diagonal direction to cause unbalance, for example, if the laundry is located at the upper portion of the right side of the drum  30  and at the same time is located at the lower portion of the left side of the drum  30 , unbalance is generated, whereby noise of the laundry treating apparatus may be generated. 
     Therefore, to solve unbalance through more precise control, it is preferable that the upper sensor  83  and the lower sensor  85  are respectively provided at the upper portion of the side of the tub  20  and the lower portion of the side of the tub  20 . 
       FIG. 3  illustrates an example of an upper balancer provided in the present invention. 
     Referring to  FIG. 3( a ) , the laundry treating apparatus of the present invention may include an upper balancer  31  provided in a hollow shape to solve unbalance at the upper portion of the drum  30 . 
     Since the upper balancer  31  is provided to surround the drum  30  and the laundry should be put into or taken out of the drum  30 , it is preferable that the upper balancer  31  is provided in a hollow shape provided with an opening at the center. 
     The upper balancer  31  may include an upper housing  311  providing a space for receiving water for solving unbalance, a first barrier portion  313  provided inside the upper housing  311 , a first water supply unit  315  provided to solve unbalance by supplying water to the inside of the upper housing  311 , and a first drainage unit  317  for discharging the water received in the upper housing  311  after solving unbalance. 
     The upper housing  311  may include a first upper housing  3111  forming an inner circumference surface of the upper balancer  31 , and a second upper housing  3113  for forming an outer circumference surface of the upper balancer  31 . 
     In more detail, a section of the first upper housing  3111  may be provided in a vertical direction to form the inner circumference surface of the upper balancer  31 , and a section of the second upper housing  3113  may be provided to form the lower surface, the outer circumference surface and the upper surface of the upper balancer  31 . 
     An upper surface of the second upper housing  3113  may be provided to be spaced apart from the first upper housing  3111  at a predetermined interval. 
     This is to provide a path for supplying water to the upper balancer  31  to solve unbalance. In other words, the upper surface of the first upper housing  3111  and the upper surface of the second upper housing  3113  may be formed to be spaced apart from each other to form the path that can supply water. 
     That is, the shapes of the first upper housing  3111  and the second upper housing  3113  have only to be provided to form the path for supplying water to the upper balancer  31  as described above without limitation to the shapes shown in  FIG. 3 . 
     The shape of the first water supply unit  315  is not limited to the shape shown in  FIG. 3 . That is, the shape of the first water supply unit  315  has only to be provided to supply water to the upper housing  311  without stopping rotation of the drum  30  in a state that the drum  30  is rotated. 
     The first drainage unit  317  may be provided at the lower end of the first upper housing  3111 . 
     The laundry treating apparatus of the present invention may solve unbalance generated in the drum  30  by supplying water in an opposite direction of the laundry in a state that the drum  30  is rotated. 
     After unbalance is solved, if the water supplied into the upper housing  311  is not drained, another unbalance may be generated. 
     Therefore, after unbalance is solved in a state that the drum  30  is rotated, rotation of the drum  30  should be stopped, and the water received in the upper housing  311  should be drained in a state that rotation of the drum  30  is stopped. Therefore, it is preferable that the first drainage unit  317  is provided at the lower portion of the inner side of the upper housing  311 , that is, the lower portion of the first upper housing  3111 . 
     That is, the first drainage unit  317  may be provided to drain the water received in the upper housing  311  in a direction vertical to a gravity direction. 
     While the drum  30  is being rotated, the upper balancer  31 , the upper housing  311  and the water supplied into the upper housing  311  perform circular motion, whereby a centrifugal force acts on an outer direction of a radius direction based on the rotation center of the drum  30 . 
     Therefore, the water supplied into the upper housing  311  is not drained due to the centrifugal force while the drum  30  is being rotated, whereby unbalance may be solved. After unbalance is solved, rotation of the drum  30  is stopped, whereby the water received in the upper housing  311  may be drained into the drum through the first drainage unit  317 . 
     The first barrier portion  313  may include a plurality of first barriers provided inside the upper housing  311  to partition the inside of the upper housing  311 . 
     Although the first barrier portion  313  is provided to partition the inside of the upper housing  311  into 8 spaces in  FIG. 3( b ) , the number of the inner spaces of the upper housing  311 , which are partitioned by the first barrier portion  313 , is not limited to the example of  FIG. 3( b ) . That is, the number of the first barriers  313  has only to be provided to solve unbalance, and may be provided differently if necessary. 
       FIGS. 4, 5 and 6  illustrate an example of a lower balancer provided in the present invention. 
     Referring to  FIG. 4 , the laundry treating apparatus of the present invention may include a lower balancer  32  provided in a hollow shape to solve balance at the lower portion of the drum  30 . 
     The laundry treating apparatus of the present invention may further include a power unit  40  for rotating the drum  30 . The power unit  40  may be provided on the lower surface of the drum  30 . Therefore, it is preferable that the lower balancer  32  is provided in a hollow shape to prevent interference with the power unit  40  from occurring. 
     The lower balancer  32  may include a lower housing  321  providing a space for receiving water for solving unbalance, a second barrier portion  323  provided inside the lower housing  321 , a second water supply unit  325  provided to solve unbalance by supplying water to the inside of the lower housing  321 , and a second drainage unit  327  for discharging the water received in the lower housing  321  after solving unbalance. 
     The lower housing  321  may include a first lower housing  3211  forming an inner circumference surface of the lower balancer  32 , and a second lower housing  3213  for forming an outer circumference surface of the lower balancer  32 . 
     In more detail, a section of the first lower housing  3211  may be provided in a vertical direction to form the inner circumference surface of the lower balancer  32 , and a section of the second lower housing  3213  may be provided to form the lower surface, the outer circumference surface and the upper surface of the lower balancer  32 . 
     An upper surface of the second lower housing  3213  may be provided to be spaced apart from the first lower housing  3211  at a predetermined interval. 
     This is to provide a path for supplying water to the lower balancer  32  to solve unbalance. In other words, the upper surface of the first lower housing  3211  and the upper surface of the second lower housing  3213  may be formed to be spaced apart from each other to form the path that can supply water. 
     That is, the shapes of the first lower housing  3211  and the second lower housing  3213  have only to be provided to form the path for supplying water to the lower balancer  32  as described above without limitation to the shapes shown in  FIG. 4 . 
     The shape of the second water supply unit  325  is not limited to the shape shown in  FIG. 4 . That is, the shape of the second water supply unit  325  has only to be provided to supply water to the lower housing  321  without stopping rotation of the drum  30  in a state that the drum  30  is rotated. 
     The second drainage unit  327  may be provided at the lower end of the first lower housing  3211 . 
     The laundry treating apparatus of the present invention may solve unbalance generated in the drum  30  by supplying water in an opposite direction of the laundry in a state that the drum  30  is rotated. 
     After unbalance is solved, if the water supplied into the lower housing  321  is not drained, another unbalance may be generated. 
     Therefore, after unbalance is solved in a state that the drum  30  is rotated, rotation of the drum  30  should be stopped, and the water received in the lower housing  321  should be drained in a state that rotation of the drum  30  is stopped. Therefore, it is preferable that the second drainage unit  327  is provided at the lower portion of the inner side of the lower housing  321 , that is, the lower portion of the first lower housing  3211 . 
     While the drum  30  is being rotated, the lower balancer  32 , the lower housing  321  and the water supplied into the lower housing  321  perform circular motion, whereby a centrifugal force acts on an outer direction of a radius direction based on the rotation center of the drum  30 . 
     Therefore, the water supplied into the lower housing  321  is not drained due to the centrifugal force while the drum  30  is being rotated, whereby unbalance may be solved. After unbalance is solved, rotation of the drum  30  is stopped, whereby the water received in the lower housing  321  may be drained into the drum through the second drainage unit  327 . 
     The second barrier portion  323  may include a plurality of second barriers provided inside the lower housing  321  to partition the inside of the lower housing  321 . 
     Although the second barrier portion  323  is provided to partition the inside of the lower housing  321  into 8 spaces in  FIG. 5 , the number of the inner spaces of the lower housing  321 , which are partitioned by the second barrier portion  323 , is not limited to the example of  FIG. 5 . That is, the number of the second barriers  323  has only to be provided to solve unbalance, and may be provided differently if necessary. 
     The second barrier portion  323  provided in the lower balancer  32  will be described with reference to  FIG. 6 . Although the structure of the second barrier portion  323  of the lower balancer  32  is only shown in  FIG. 6 , this structure may equally be applied to the upper balancer  31 . 
     The second barrier portion  323  may be provided to be extended in a direction vertical to a gravity direction so as to partition the inside of the lower housing  321 . 
     The second barrier portion  323  may include second main barriers  3231  partitioning the inside of the lower housing  321  into a plurality of spaces, and at least one or more second sub barriers  3233  provided in the partitioned spaces. 
     Unbalance generated in the laundry treating apparatus of the present invention may be solved even in the case that the second barrier portion  323  includes the second main barriers  3231  only. 
     However, since the drum  30  is rotated, the water received in the lower housing  321  is concentrated on an opposite direction of a rotational direction by its inertia, whereby unbalance cannot be solved efficiently. 
     To solve this, the upper balancer  31  and the lower balancer  32  of the laundry treating apparatus according to the present invention may include at least one or more second sub barriers  3233  provided between the main barriers  3231  to have their respective heights different from each other. 
     In more detail, the second sub barriers  3233  may be provided to have their heights which become gradually higher along the rotational direction of the drum  30 . 
     In this case, concentration of the water received in the upper housing  311  or the lower housing  321  due to inertia may be prevented from occurring, whereby unbalance may be solved more efficiently. 
     For example, in  FIG. 6 , one second main barrier  3231  is provided and five second sub barriers  3233  are provided. 
     The five second sub barriers  3233  may be provided as B6, B5, B4, B3 and B2 of which heights become higher in due order, and the second main barrier  3231  may be provided as the highest B1. 
     However, the number of second sub barriers  3233  is not limited to this embodiment, and may be provided differently depending on the need of a user. 
     The second main barrier  3231  should be provided to partition the lower housing  321 . However, since the second sub barriers  3233  are intended to prevent concentration of the water received in the lower housing  321  from occurring as described above, the second sub barriers  3233  should be provided so as not to partition the lower housing  321 . 
     That is, the water received in the lower housing  321  should be provided to freely move among the plurality of second sub barriers  3233 . 
     Therefore, as shown in  FIG. 6 , it is preferable that a length of the lower surface of the second sub barriers  3233  is shorter than a length of the lower surface of the second main barrier  3231  as much as A in a diameter direction. 
     However, the length difference between the lower surface of the second main barrier  3231  and the lower surface of the second sub barrier  3233  may be provided differently if necessary, and is not limited to the ratio shown in  FIG. 6 . 
       FIG. 7  illustrates an example of a method for controlling unbalance generated in a laundry treating apparatus of the present invention. 
     In more detail, the method of  FIG. 7  relates to a control method for determining a position of water supplied to the upper balancer  31  or the lower balancer  32  to solve unbalance generated in the laundry treating apparatus of the present invention more efficiently. 
     As described above, unbalance means that mass distribution is not maintained uniformly around the rotary shaft of the drum  30  when the drum  30  is rotated. This may mean that the drum  30  is rotated in a state that the laundry in the drum  30  is concentrated on one side. 
     The laundry treating apparatus of the present invention solves unbalance by identifying the concentrated position of the laundry and spraying water in an opposite direction of the concentrated position of the laundry based on the rotary shaft of the drum  30 . Since the laundry has its mass and rotated together with the drum  30 , in case of a primary control, an inertia error ε 1  is generated by inertia as shown in  FIG. 7( a ) . 
     Therefore, to overcome the inertia error ε 1  according to the primary control, a secondary control is performed considering the primary control value. 
     Meanwhile, even though the secondary control is performed considering the inertia error ε 1  generated in the primary control as shown in  FIG. 7( b ) , a counter electromotive force error ε 2  may be generated. 
     The counter electromotive force means an electromotive force generated in an opposite direction of an electromotive force of a power source in either an armature coil of an electric motor or a primary coil of a transformer. 
     That is, although the secondary control is performed in an opposite direction to compensate for the inertia error ε 1 , the counter electromotive force error ε 2  is generated by the counter electromotive force. 
     Therefore, the laundry treating apparatus of the present invention may include a third control for more precise control as shown in  FIG. 7( c ) . 
     The third control may control the balancers  31  and  32  by considering the counter electromotive force error ε 2  generated in the secondary control. 
     A residual error ε 3  may be generated through the aforementioned control. If this residual error ε 3  is within a preset allowable error mε, it is possible to efficiently solve unbalance. 
       FIG. 8  is a flow chart illustrating an example of a control method for determining a water supply amount and a water supply position of water supplied to an upper balancer and a lower balancer provided in a laundry treating apparatus of the present invention. 
     Referring to  FIG. 8 , the control method of the laundry treating apparatus according to the present invention may include a distance measuring step S 10  of measuring an upper distance YT and a lower distance YB through the upper sensor  83  and the lower sensor  85 , and a measurement comparing step S 20  of determining whether the upper distance YT and the lower distance YB measured in the distance measuring step are the same as each other. 
     If profiles of the upper distance YT and the lower distance YB are the same as each other in the measurement comparing step S 20 , the laundry in the drum  30  is concentrated on the upper portion of the drum  30  or the lower portion of the drum  30 . Since the laundry is not concentrated in a diagonal direction when viewed from a front end of the drum  30 , it is possible to solve unbalance by supplying water to only one of the upper balancer  31  and the lower balancer  32 . 
     Although the control method for supplying water to the lower balancer  32  only is shown in this embodiment, the control method is not limited to this embodiment and water may be supplied to only the upper balancer  31  if necessary. 
     Therefore, if the profiles of the upper distance YT and the lower distance YB are the same as each other in the measurement comparing step S 20 , the control method of the laundry treating apparatus according to the present invention may include a lower amplitude measuring step S 30  of measuring an amplitude of the lower distance YB from the profile of the lower distance YB, and a lower phase measuring step S 40  of measuring a phase of the lower distance YB. 
     The control method may further include a lower water supply amount determining step S 31  of determining a water supply amount of the lower balancer  32  through the amplitude of the lower distance YB measured in the lower amplitude measuring step S 30 , and a first lower water supply position determining step S 41  of determining a water supply position of the lower balancer through the phase of the lower distance YB. 
     Afterwards, the laundry treating apparatus of the present invention may solve unbalance through a first lower balancer water supply step S 50  of supplying water to the lower balancer  32  based on the water supply amount and the water supply position, which are determined by the lower water supply amount determining step S 31  and the first lower water supply position determining step S 41 . 
     If the profiles of the upper distance YT and the lower distance YB are not the same as each other in the measurement comparing step S 20 , since the laundry is concentrated in a diagonal direction when viewed from a front end of the drum  30 , water should be supplied to both the upper balancer  31  and the lower balancer  32  to solve unbalance. 
     In this case, the water should be supplied to the upper balancer  31  and the lower balancer  32  unlike the first lower balancer water supply step S 50 . Since the upper balancer  31  and the lower balancer  32  are provided on the upper and lower portions of the drum  30  in a single body with the drum  30  to be rotated together with the drum  30 , the upper balancer  31  and the lower balancer  32  are coupled to each other. Unbalance cannot be solved by simple water supply depending on the amplitude and the phase of the profiles of the upper distance YT and the lower distance YB. 
     In other words, the phase of the profile of the upper distance YT used for control of the upper balancer  31  should again be applied to the control of the lower balancer  32 . 
     Therefore, if the profiles of the upper distance YT and the lower distance YB are not the same as each other in the measurement comparing step S 20 , the control method of the laundry treating apparatus may include an upper amplitude measuring step S 60  of measuring an amplitude of the upper distance YT, an upper water supply amount determining step S 61  of determining a water supply amount of the upper balancer  31  through the determined amplitude of the upper distance YT, an upper phase measuring step S 70  of measuring a phase of the upper distance YT, an upper water supply position determining step S 71  of determining a water supply position of the upper balancer  31  through the measured phase of the upper distance, and an upper balancer water supply step S 80  of supplying water to the upper balancer  31  based on the water supply amount and the water supply position, which are determined by the upper water supply amount determining step S 61  and the upper water supply position determining step S 71 . 
     The control method may further include a lower balancer water supply amount determining step S 31  of determining a water supply amount of the lower balancer through the lower amplitude measured in the lower amplitude measuring step of  30  of measuring the lower amplitude, a phase difference computing step S 90  of computing a phase difference between the lower phase measured in the lower phase measuring step S 40  of measuring a lower phase and the upper phase measured in the upper phase measuring step S 70  of measuring the upper phase, a second lower water supply position determining step S 91  of determining a water supply position of the lower balancer by using the phase difference between the upper phase and the lower phase, which is computed by the phase difference computing step S 90 , and a second lower balancer water supply step S 51  of supplying water to the lower balancer based on the water supply amount and the water supply position, which are determined by the lower water supply amount determining step S 31  and the second lower water supply position determining step S 91 . 
       FIGS. 9 and 10  illustrate an example of water supply units provided in an upper balancer and a lower balancer to supply water. 
     Referring to  FIG. 9 , since the laundry treating apparatus of the present invention should supply water to the upper balancer  31  in a state that the drum  30  is rotated, the laundry treating apparatus may further include a first water supply unit  315 . 
     The first water supply unit  315  may include a first water supply nozzle  3153  which is a means for supplying water into the upper balancer  31  by using a predetermined pressure, and a first water supply guider  3151  provided to guide the water sprayed from the first water supply nozzle  3153  into the upper housing  311 . 
     The water supplied from the first water supply unit  315  moves into the upper housing  311 . In more detail, the water may be supplied into the upper housing  311  through a path formed by the first and second upper housings  3111  and  3113  spaced apart from each other at a predetermined distance. 
     Referring to  FIG. 10 , since the laundry treating apparatus of the present invention should supply water to the lower balancer  32  in a state that the drum  30  is rotated, the laundry treating apparatus may further include a second water supply unit  325 . 
     The second water supply unit  325  may include a second water supply nozzle  3253  which is a means for supplying water into the lower balancer  32  by using a predetermined pressure, and a second water supply guider  3251  provided to guide the water sprayed from the second water supply nozzle  3253  into the lower housing  321 . 
     The water supplied from the second water supply unit  325  moves into the lower housing  321 . In more detail, the water may be supplied into the lower housing  321  through a path formed by the first and second lower housings  3211  and  3213  spaced apart from each other at a predetermined distance. 
     It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit and essential characteristics of the invention. Thus, the above embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the invention should be determined by reasonable interpretation of the appended claims and all change which comes within the equivalent scope of the invention are included in the scope of the invention.