Abstract:
Mechanism of maintaining balance of a washing machine during operation thereof. A lower balancer is coupled to a lower portion of the inner tub of the washing machine. The lower balancer has a receptacle for temporarily retaining washing water. During rotation of the inner tub, the retained water moves laterally within the lower balancer and presses an “L shaped” balancing side wall member in the direction of centrifugal force. Once the rotation stops, retained water drains automatically from the lower balancer.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Korean Patent Application No. 10-2014-0125821, filed on Sep. 22, 2014, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
       TECHNICAL FIELD 
       [0002]    The present disclosure relates to washing machine and washing method, and more particularly, to rotation balance mechanism of washing machine. 
       BACKGROUND 
       [0003]    In general, a washing machine is an apparatus that eliminates foreign matter or substances on or in laundry by agitating and/or rotating water and the laundry. A washing machine typically uses a motor and performs washing, rinsing, and spin-drying processes to clean the laundry. 
         [0004]    Washing machines may be classified into types including cylinder type washing machines, agitator type washing machines, and pulsator type washing machines. A pulsator type washing machine washes the laundry using water flow generated by motion (e.g., rotation) of a pulsator in a washing tub. 
         [0005]    Basically, a pulsator type washing machine includes an outer tub to store water, a drum (or a basket) to contain the laundry, and a drive motor disposed below the outer tub to rotate the drum. The drum is an inner tub disposed inside the outer tub. 
         [0006]    A hydraulic balancer mounted at an upper side of the drum is used to reduce vibration caused by eccentricity resulting from unbalanced distribution of the laundry load. 
         [0007]    However, in a conventional washing machine, a hydraulic balancer is mounted only at the upper side of the drum. As a result, undesirable vertical vibration at a lower side of the drum is not effectively reduced due to an unbalanced distribution of the laundry load. 
         [0008]    In a case in which a balancer is also mounted at the lower side of the drum, in order to solve this problem, the weight of the washing tub as well as the overall weight of the washing machine is undesirably increased. Moreover, other components of the washing machine, such as the drive motor for operating the washing tub and the suspension system, have to be substantially redesigned to accommodate the lower balancer. 
       SUMMARY 
       [0009]    It would be advantageous to provide a mechanism and method to maintain balance at both the upper and lower sides of a washing tub without introducing significant weight increase. 
         [0010]    Accordingly, an exemplary embodiment of the present disclosure provides a washing machine including: an outer washing tub which stores washing water; an inner washing tub which is positioned inside the outer washing tub and has water holes formed therein; a drive unit which rotates the inner washing tub; and a lower balancer which is formed at a lower side of the inner washing tub, which stores a part of the washing water and maintains balance of the inner washing tub when the inner washing tub is rotated. 
         [0011]    The washing water which is used to maintain balance at the lower side of the inner washing tub may be drained to the outside when the inner washing tub is stopped, or when the rotation is stopped. 
         [0012]    The lower balancer may include a water remaining portion having a container shape which is opened upward and stores a part of the washing water, and a balancing side wall portion which is formed outside the water remaining portion in a direction of centrifugal force, and has a drain port that is formed at a lower side of the balancing side wall portion in a direction toward a rotation center of the inner washing tub. 
         [0013]    In one embodiment, the balancing side wall portion may include an “L”-shaped cross section. 
         [0014]    A height of an outer wall body of the water remaining portion may be greater than a height of an inner wall body of the water remaining portion. 
         [0015]    The washing machine may further include an upper balancer which is formed at an upper side of the inner washing tub. 
         [0016]    Another exemplary embodiment of the present disclosure provides a washing method which includes a process of spin-drying laundry by rotating an inner washing tub, the washing method including: storing a part of the washing water at a lower side of the inner washing tub; maintaining balance at the lower side of the inner washing tub by moving the stored washing water from the lower side of the inner washing tub in a lateral direction by centrifugal force when the inner washing tub is rotated; and draining the washing water, which is moved from the lower side of the inner washing tub in the lateral direction, by gravity when the rotation of the inner washing tub is stopped. 
         [0017]    Balance at upper and lower sides of the inner washing tub may be dually maintained when the inner washing tub is rotated, by maintaining balance at the upper side of the inner washing tub at all times. 
         [0018]    According to the exemplary embodiment of the present disclosure, the washing machine and the washing method may advantageously maintain balance at both the upper and lower sides of the washing tub, and minimize an increase in overall weight of the washing tub. 
         [0019]    This summary contains, by necessity, simplifications, generalizations and omissions of detail; consequently, those skilled in the art will appreciate that the summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the present invention, as defined solely by the claims, will become apparent in the non-limiting detailed description set forth below. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    Embodiments of the present invention will be better understood from a reading of the following detailed description, taken in conjunction with the accompanying drawing figures in which like reference characters designate like elements and in which: 
           [0021]      FIG. 1  is a cross-sectional view of an exemplary washing machine including a lower balancer according to an exemplary embodiment of the present disclosure; 
           [0022]      FIG. 2  is a cross-sectional view illustrating an exemplary lower balancer used in the washing machine of  FIG. 1 ; 
           [0023]      FIGS. 3 ,  4  and  5  are cross-sectional views sequentially illustrating operational states of the washing machine according to the exemplary embodiments of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of embodiments of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be recognized by one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the embodiments of the present invention. The drawings showing embodiments of the invention are semi-diagrammatic and not to scale and, particularly, some of the dimensions are for the clarity of presentation and are shown exaggerated in the drawing Figures. Similarly, although the views in the drawings for the ease of description generally show similar orientations, this depiction in the Figures is arbitrary for the most part. Generally, the invention can be operated in any orientation. 
       Notation and Nomenclature: 
       [0025]    It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the present invention, discussions utilizing terms such as “processing” or “accessing” or “executing” or “storing” or “rendering” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system&#39;s registers and memories and other computer readable media into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or client devices. When a component appears in several embodiments, the use of the same reference numeral signifies that the component is the same component as illustrated in the original embodiment. 
       Lower Balancer of a Washing Machine 
       [0026]    Hereinafter, a washing machine  101  according to an exemplary embodiment of the present disclosure will be described with reference to  FIGS. 1 and 2 . 
         [0027]    As illustrating in  FIG. 1 , the washing machine  101  according to the exemplary embodiment of the present disclosure includes an outer washing tub  210 , an inner washing tub  220 , a drive unit  800 , and a lower balancer  320 . 
         [0028]    The washing machine  101  also includes an upper balancer  310 , a drainage device  480 , a pulsator  500 , a casing  400 , and a suspension system  600 . 
         [0029]    The casing  400  defines an exterior housing of the washing machine  101 , and the outer washing tub  210  is installed inside the casing  400 . The outer washing tub  210  stores washing water for laundry. 
         [0030]    The inner washing tub  220  (e.g., a basket) is rotatably positioned inside the outer washing tub  210 . The inner washing tub  220  has water holes for water to flow in and out of the inner washing tub  220 . 
         [0031]    The pulsator  500  is rotatably coupled to the bottom of the inner washing tub  220  and servers to agitate the water while it rotates. 
         [0032]    The drive unit  800  drives the rotation of the pulsator  500  and the inner washing tub  220 . More specifically, the drive unit  800  may include a drive motor  810 , a driving shaft  830  coupled to the drive motor  810 , and a clutch device  820  which may intermittently supply a rotational force to the driving shaft  830 . 
         [0033]    When the drive motor  810  rotates the pulsator  500  during a washing process, the pulsator  500  in turn agitates the washing water and the laundry contained in the inner washing tub  220 . 
         [0034]    When the drive motor  810  rotates the inner washing tub  220  during a spin-drying process, the laundry is spin-dried as the moisture is removed by centrifugal force. 
         [0035]    When the washing process is completed, e.g., before the spin-drying process, the drainage device  480  drains the washing water from the outer washing tub  210  to the outside of the washing machine. The drainage device  480  may include a drain pipe coupled to the outer washing tub  210 , and a control valve which opens and closes the drain pipe. 
         [0036]    The upper balancer  310  is located at an upper side of the inner washing tub  220 . It is appreciated that the upper balancer  310  is filled with a balance maintaining fluid. The balance maintaining fluid is retained in the upper balancer  310  and is not regularly discharged from the upper balancer  310 . 
         [0037]    According to the present disclosure, the lower balancer  320  is located at a lower side of the inner washing tub  220 . The lower balancer  320  receives a part of the washing water, e.g., when the washing water is drained. Advantageously, the lower balancer  320  temporarily stores the part of the washing water as a balancing weight for maintaining balance of the inner washing tub  220 , when the inner washing tub  220  is rotated, for example during a spin-dry process. When the rotation of the inner washing tub is stopped, the water is then drained from the lower balancer to the outside. That is, the washing water is not always retained in the lower balancer  320 . 
         [0038]    Specifically, as illustrated in  FIG. 2 , the lower balancer  320  may be annular-shaped overall and include a receptacle  321  to retain water and a balancing side wall portion  325 . 
         [0039]    In this example, the receptacle  321  and the balancing side wall portion  325  are annular-shaped, but the present disclosure is not limited thereto. For example, in some embodiments, a plurality of receptacles  321  and a plurality of balancing side wall portions  325  may be formed radially, e.g., in different radii relative to a rotation center of the inner washing tub  220 . 
         [0040]    The receptacle  321  is an annular groove formed by an inner upright wall, an outer upright wall and a horizontal bottom. The receptacle  321  opens upward so it can hold washing water. In this example, the outer annular wall of the receptacle  321  is coupled to a lower portion of the inner washing tub  220  and has an opening so the water can flow from the receptacle to the space formed between outer annular wall and the balancing side wall portion  325 , as will be described below. 
         [0041]    The balancing side wall portion  325  is formed outside the receptacle  321  along the direction of the centrifugal force. The balancing side wall portion  325  has an upright part having a larger radius than the outer upright wall of the receptacle  321 . The balancing side wall portion  325  may have a drain port  329  (or draining opening) at a lower side of the balancing side wall portion  325  in a direction toward the rotation center of the inner washing tub  220 . In this example, the balancing side wall portion  325  has an “L”-shaped cross section and includes the upright part and a horizontal part. The space between the receptacle  321  and the horizontal part of the side wall portion forms the drain port. 
         [0042]    It is appreciated that the washing water stored in the receptacle  321  can flow to the balancing side wall portion  325  via the opening on the outer upright wall under the centrifugal force generated by the rotation of the inner washing tub  220 . The washing water presses the balancing side wall portion  325  under the impact of the centrifugal force. Consequently, in accordance with embodiments of the present disclosure, the combination of the lower balancer  320  and the upper balancer  310  can advantageously maintain the balance of the inner washing tub  220  simultaneously at both the upper and lower sides, thereby attenuating the vibration more effectively than using merely an upper balancer. 
         [0043]    In one embodiment, the height of the outer upright wall of the receptacle  321  is greater than the height of the inner upright wall of the receptacle  321 , such that the washing water in the receptacle  321  only flows to the balancing side wall portion  325  when the inner washing tub  220  rotates at a predetermined speed or higher. 
         [0044]    Accordingly, when the inner washing tub  220  rotates at such a speed that the washing water flowing to the balancing side wall portion  325  is not drained due to the centrifugal force but remains in the balancing side wall portion  325 , the washing water in the receptacle  321  may flow to the balancing side wall portion  325 . 
         [0045]    In the exemplary embodiment of the present disclosure, the lower balancer  320  may be configured such that the balancing is only effectuated when the inner washing tub  220  rotates at a sufficiently high speed where the vibration becomes serious. 
         [0046]    As described above, according to the exemplary embodiments of the present disclosure, the washing machine  101  can effectively advantageously attenuate vibration caused by the rotation of the inner washing tub  220 . 
         [0047]    As illustrated in  FIG. 1 , the suspension system  600  has one side coupled to the outer washing tub  200  and the other side coupled to the casing  400 . The suspension system can further dampen the vibration of the outer washing tub  210  and the inner washing tub  220  caused by the rotation of the drive motor  810 . 
         [0048]    With the aforementioned configuration, the washing machine  101  according to the exemplary embodiments of the present disclosure can maintain balance of the inner washing tub  220  at both the upper and lower sides of the inner washing tub  220 . At the same time, no significant product weight of the inner washing tub  220  as well as the washing machine  101  is introduced due to the addition of the lower balancer according to the present disclosure. 
         [0049]    Hereinafter, a washing method using the washing machine  101  according to the exemplary embodiment of the present disclosure will be described with reference to  FIGS. 2 ,  3 ,  4  and  5 . In this case, the washing method includes a process of spin-drying laundry by rotating the inner washing tub  220 . 
         [0050]    First, as illustrated in  FIG. 2 , the outer washing tub  210  is filled with the washing water during a washing process. At the same time, the receptacle  321  of the lower balancer  320  is also filled with the washing water. 
         [0051]    Next, as illustrated in  FIG. 3 , when the washing water in the outer washing tub  210  is drained through the drainage device  480 , most of the washing water in the inner washing tub  220  is drained to the outside of the washing machine, but the receptacle  321  of the lower balancer  320  can retain some amount of the washing water. 
         [0052]    That is, while the majority of the washing water is drained from the inner washing tub  210 , some washing water is retained at the lower side of the inner washing tub  220  by the lower balancer  320 . 
         [0053]    As illustrated in  FIG. 4 , when the inner washing tub  220  rotates and a spin-drying process begins, the washing water in the receptacle  321  moves to the balancing side wall  325  under the centrifugal force. 
         [0054]    That is, the washing water stored at the lower side of the inner washing tub  220  moves from the lower side of the inner washing tub  220  in a lateral direction, thereby maintaining balance at the lower side of the inner washing tub  220 . 
         [0055]    Some washing water, which flows out during the spin-dry process, may move to the balancing side wall  325 . 
         [0056]    Due to the centrifugal force, the washing water moving to the balancing side wall  325  does not flow downward by gravity but is retained within the balancer. The retained washing water presses the balancing side wall  325  in the direction of centrifugal force, thereby maintaining balance at the lower side of the inner washing tub  220 . 
         [0057]    As described above, according to the exemplary embodiment of the present disclosure, the balance at both the upper and lower sides of the inner washing tub  220  can be maintained. That is, the vibration caused by the rotation of the inner washing tub  220  can be effectively attenuated during the spin-drying process. 
         [0058]    Next, as illustrated in  FIG. 5 , when the spin-drying process is finished and the rotation of the inner washing tub  220  is stopped, the washing water, which has moved from the lower side of the inner washing tub  220  in the lateral direction, is drained downward by gravity. Specifically, as the centrifugal force disappears, the washing water lodged the balancing side wall  325  drains through the drain port  329 . 
         [0059]    With the aforementioned process, the washing method using the washing machine  101  according to the exemplary embodiments of the present disclosure can maintain balance of the inner washing tub  220  at both the upper and lower sides of the inner washing tub  220 , without introducing significant product weight of the washing machine  101 . 
         [0060]    Although certain preferred embodiments and methods have been disclosed herein, it will be apparent from the foregoing disclosure to those skilled in the art that variations and modifications of such embodiments and methods may be made without departing from the spirit and scope of the invention. It is intended that the invention shall be limited only to the extent required by the appended claims and the rules and principles of applicable law.