Patent Publication Number: US-9416478-B2

Title: Washing machine and washing method

Description:
This claims priority to Korean Application No. 10-2009-0027664 filed in Korea on Mar. 31, 2009, and Korean Application No. 10-2009-0087141 filed in Korea on Sep. 15, 2009 the entirety of which is incorporated herein by reference. 
     BACKGROUND 
     1. Field 
     This relates to a washing machine and associated washing method. 
     2. Background 
     Generally, a washing machine cleans laundry items by washing, rinsing, and spinning in order to separate dirt from the items using water, wash agents such as detergent, and a mechanical operation. An agitator type washing machine washes laundry items by rotating a washing rod positioned at the center of the washing tub in left and right directions. A pulsator type washing machine washes laundry using friction force between the laundry items and water current generated by a circular plate shaped pulsator formed in a lower portion of the washing tub. A drum type washing machine washes laundry items by rotating a drum containing washing water, wash agents and the laundry items. 
     In the drum type washing machine, a tub holding wash fluid therein is mounted within a cabinet, and a drum having the laundry items loaded therein is mounted within the tub, with a motor that rotates the drum being mounted at the rear of the tub. A drive shaft is axially connected to a rear side of the drum, passing through the tub. A lifter is mounted within the drum so as to lift laundry during a rotation of the drum. In such a drum type washing machine, laundry items are lifted by the lifter mounted inside the drum during rotation of the drum and then released from the inside of the drum and dropped as the drum rotates (referred to as tumbling). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein: 
         FIG. 1  is a perspective view of a washing machine according to an exemplary embodiment as broadly described herein; 
         FIG. 2  is a side cross-sectional view of the washing machine shown in  FIG. 1 ; 
         FIGS. 3A-3C  illustrate a squeezing motion in a washing method according to an exemplary embodiment as broadly described herein; 
         FIGS. 4A-4E  illustrate various drum motions of the washing machine and associated method as embodied and broadly described herein; 
         FIG. 5  is a flow diagram of a washing method according to an exemplary embodiment as broadly described herein; and 
         FIG. 6  is a graph of rotation speed of the drum with respect to time. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments of a washing machine and washing method will be hereinafter described in detail with reference to the accompanying drawings. 
     The exemplary washing machine  100  shown in  FIGS. 1 and 2  may include a cabinet  110 , a tub  120  installed in the cabinet  110 , a drum  130  rotatably installed in the tub  120 , a driver  140  for rotating the drum  130  by applying a torque to the drum  130 , and a controller  115  for controlling an overall operation of the washing machine  100  in response to an external input. 
     The cabinet  110  may include a cabinet main body  111 , a cabinet cover  112  coupled to a front surface of the cabinet main body  111 , and a top plate  116  coupled to a top of the cabinet main body  111 . The cabinet cover  112  may include a laundry entrance hole  114  and a door  113  rotatably coupled to the cabinet cover  112  so as to open and close the laundry entrance/exit hole  114 . 
     The washing machine  100  may also include a gasket  121  disposed between the inlet of the drum  130  and the laundry entrance hole  114 . The gasket  121  alleviates impact transferred to the door  113  during rotation of the drum  130  and also prevents washing fluid in the tub  120  from leaking out. The tub  120  installation in the cabinet  110  may be damped by springs and a damper. 
     The tub  120  contains washing fluid during operation of the washing machine  100 . A plurality of holes for passing washing fluid therethrough may be formed in the drum  130 , and a lifter  135  may be provided on an inner circumferential surface of the drum  130  so as to lift the laundry items by a predetermined height when the drum  130  rotates. 
     The driver  140  rotates the drum  130  within the tub  120 . The driver  140  may include a motor and a switching element for controlling the motor. The driver  140  may implement various motions in response to inputs received by the controller  115 . 
     A supply valve  153  may introduce washing fluid from an external source, and a supply hose  151  may guide the washing fluid from the supply valve to a detergent box  152 , the detergent box  152  containing washing agents such as a laundry detergent, bleach, a fabric softener, and the like. A supply bellows  154  may introduce the washing fluid including a washing agent from the detergent box  152  into the drum  130 . The supply valve  153 , the supply hose  151 , and the supply bellows  154  may be connected/coupled so as to form a fluid supply device. 
     The washing machine  100  may also include a discharge hose  162  for discharging washing fluid from the tub  120 , a pump  163  for pumping the discharged the washing fluid, a circulation path  164  for guiding washing fluid to the drum  130 , a nozzle  165  provided at the gasket for introducing the washing fluid into the drum  130 , and a drain path  173  for guiding the washing fluid to an outside of the cabinet  110 . The discharge hose  162 , the pump  163 , the circulation path  164 , and the nozzle  165  may be coupled/connected so as to form a circulation device, and the discharge hose  162 , the pump  163 , and the drain path  173  may be coupled/connected so as to form a draining device. The discharge hose  162  and the pump  163  may be provided separately for the circulation device and the draining device, respectively. 
     The controller  115  may control an overall operation of the washing machine  100  in response to an external input, and may display a current operation state. The controller  115  may be provided at an upper portion of the cabinet cover  112 . The controller  115  may be provided with a manipulation button for receiving a user input, a microcomputer for controlling the operation of the washing machine  100 , and a display device such as an LCD display. 
       FIGS. 3A-3C  illustrate a squeezing motion in a washing method as embodied and broadly described herein. In this method, a squeezing motion is a motion repeated in a short cycle in which the drum  130  is accelerated to a high speed during a wash cycle or rinse cycle. This acceleration causes laundry  10  in the drum  130  to rotate, clinging to or squeezing against the inner circumferential surface of the drum  130 . The drum  130  is then decelerated to cause the laundry  10  to be separated or released from the inner circumferential surface of the drum  130 . 
     More specifically, as shown in  FIG. 3A , when the drum  130  rotates at a high speed, the laundry  10  in the drum  130  rotates, clinging to the inner circumferential surface of the drum  130 . For example, the drum  130  may rotate to about 100 RPM to cause the laundry  10  to cling to the inner circumferential surface of the drum  130  due to centrifugal force. The drum  130  and laundry  10  therein may be rotated for an appropriate amount of time at an appropriate speed so that it is evenly distributed and clings to the inner circumferential surface of the drum  130 . 
     At this time, washing fluid may be introduced from the supply bellows  154  or the nozzle  165  and evenly distributed onto the laundry  10 . That is, washing fluid may be supplied from the outside during a squeezing motion in a laundry soaking step, or washing fluid may be circulated so as to evenly soak the laundry  10  during the squeezing motion in a rinsing or washing step. 
     As shown in  FIG. 3B , when the drum  130  is decelerated, the laundry  10  is separated from the inner circumferential surface of the drum  130 . When the drum  130  is decelerated to a speed at which little to no centrifugal force is applied to the laundry  10 , the laundry  10  is separated due to gravity and the drum  130  continues to rotate, thus moving and mixing the laundry  10  uniformly. At this time, washing fluid may be introduced from the supply bellows  154  or the nozzle  165  and evenly distributed onto the laundry  10 . 
     As shown in  FIG. 3C , when the drum  130  is fully decelerated, the laundry  10  is gathered at the center of the drum  130 . For example, when the drum  130  rotates at about 50 RPM, the laundry  10  is gathered at the center of the drum  130  and rolls over. As described above, washing fluid may be introduced from the supply bellows  154  or the nozzle  165  and evenly distributed onto the laundry  10 . 
     Afterwards, the drum  130  is again accelerated in the same direction or a reverse direction so that the laundry  10  gathered at the center of the drum  130  as shown in  FIG. 3C  is rotated so as to evenly distribute the laundry  10  so that it clings to the inner circumferential surface of the drum  130 , as shown in  FIG. 3A . If the direction is reversed, the drum  130  will rotate counter-clockwise in  FIG. 3A . 
     In certain embodiments, each of the steps  3 A- 3 C may be repeated in short cycle. In certain embodiments, a cycle time in which acceleration and deceleration may be repeated may be, for example, 1 to 4 seconds, and a time to accelerate from about 50 rpm to about 100 rpm may be about 2 seconds, and in certain circumstances about 1.2 seconds. A time to decelerate from about 100 rpm to about 50 rpm may be about 1 second, and in certain circumstances about 0.5 seconds. Each of the acceleration and deceleration is repeated at least twice. 
       FIGS. 4A-4E  illustrate various drum motions of a washing machine and associated washing method as embodied and broadly described herein. 
     In  FIG. 4A , the driver  140  rotates the drum  130  in a predetermined direction so that the laundry is lifted from the lowest position of the drum  130  and is chopped in the vicinity of half the vertical height of the drum  130  (hereinafter, referred to as “tumbling motion”). In certain embodiments, the drum  130  may continuously rotate at about 45 rpm in the tumbling motion, and the laundry in the drum  130  is washed by impact and frictional force. 
     In  FIG. 4B , the driver  140  rotates the drum  130  in a predetermined direction so that the laundry is lifted from the lowest position of the drum  130  and is dropped at a height of less than half the vertical height of the drum (hereinafter, referred to as “rolling motion”). In certain embodiments, the drum  130  may continuously rotate at about 40 rpm or below in the rolling motion, and the laundry in the drum  130  is washed by bending and stretching force and frictional force by being dropped and rolling over each other/itself. 
     In  FIG. 4C , the driver  140  rotates the drum  130  in different directions so that the laundry is lifted from the lowest position of the drum  130  and dropped in the vicinity of half the height of the drum  130  (hereinafter, referred to as “swing motion”). In certain embodiments, the drum  130  rotates at about 40 rpm or below in different directions in the swing motion. The laundry in the drum  130  is washed by bending and stretching force and frictional force by being dropped and rolling over each other/itself. 
     In  FIG. 4D , the driver  140  rotates the drum  130  in a predetermined direction so that the laundry is lifted from the lowest position of the drum and dropped in the vicinity of the top of the drum  130  (hereinafter, referred to as “step motion”). In certain embodiments, the drum  130  may be rotated at about 60 rpm or above to raise the laundry in the step motion. The laundry is raised higher than half the height of the drum  130  and then the driver  140  controls the drum  130  so that the laundry is dropped in the vicinity of the top of the drum  130 . After the laundry is dropped, the drum  130  raises the laundry by rotating in the same direction again. The laundry in the drum  130  is washed by a high impact force using a head of washing fluid. 
     In  FIG. 4E , the driver  140  changes the speed of the drum  130  in short cycle so that the laundry is gathered and distributed in a repeated manner. In certain embodiments, the speed of the drum  130  in the squeezing motion may be changed in short cycle within a speed range of about 50 to 100 rpm to cause the laundry to be alternately drawn toward and separated from the inner circumferential surface of the drum  130  in a repeated manner. As the movement of the laundry is facilitated, washing deviation may be reduced and the laundry may be brought into uniform contact with the washing fluid. In addition, when the laundry clings to the inner circumferential surface of the drum  130 , the washing fluid that has soaked through the laundry may be discharged through the holes in the drum  130  as if being squeezed out of the laundry. Therefore, contaminants on the laundry may be discharged during washing as if being squeezed out, and a detergent remaining on the laundry may also be discharged as if being squeezed out. Moreover, as the laundry is repeatedly drawn toward and separated from the inner circumferential surface of the drum  130 , the user may visually check the movement of the laundry. 
       FIG. 5  illustrates a washing method according to an exemplary embodiment as broadly described herein. 
     When washing is started, an amount of laundry contained in the drum  130  is detected (S 410 ). A washing course is selected through manipulation of a button of the controller  115  and the microcomputer of the controller  115  starts the corresponding washing course and detects the amount of laundry in the drum  130 . 
     The detection of the amount of laundry in the drum  130  may be implemented by various methods or devices. In one exemplary embodiment, the driver  140  rotates the drum  130  at a predetermined speed for a predetermined period of time and then measures a deceleration time to detect the amount of laundry in the drum  130 . The longer the deceleration time of the drum  130 , the greater the amount of laundry in the drum  130 . The amount of laundry may be calculated by the microcomputer of the controller  115 , or other means as appropriate. 
     An initial supply of washing fluid is then provided (S 420 ). When the supply valve  153  is opened and washing fluid is supplied from the external source, the washing fluid is guided to the detergent box  152  along the supply hose  151  is mixed with a washing agent, and is introduced into the drum  130  by the supply bellows  154 . 
     Upon completion of the washing fluid supply or during the washing fluid supply, laundry soaking is performed (S 430 ). During laundry soaking, laundry is moved so that the laundry contained in the drum  130  may be soaked by the washing fluid supplied to the inside of the tub  120 . In general, laundry soaking is performed by a tumbling motion, but may also be performed by the above-described squeezing motion. If laundry soaking is performed by the squeezing motion, washing fluid may be introduced from the supply bellows  154  and/or the nozzle  165  and evenly distributed onto the laundry. 
     It is then determined whether or not the amount of laundry is out of a set range (S 440 ). More specifically, it is determined whether a detected amount of laundry is greater than a predetermined level so as to determine whether to perform a drum motion in the wash cycle. 
     If the amount of laundry is out of the set range, a general motion may be performed (S 450 ), and the squeezing motion may be performed (S 460 ). The general motion refers to a rolling motion, a swing motion, and a step motion, as well as the tumbling motion discussed above with respect to  FIGS. 4A-4D . 
     If the general motion is repeated when the amount of laundry is large, the laundry may become entangled, thus hindering or preventing movement of the laundry. Accordingly, the general motion may be performed for a predetermined period of time, and then the squeezing motion may be performed. If the amount of laundry is small, the laundry may cling to the inner circumferential surface of the drum  130  even at a low rpm, thus hindering the squeezing motion. 
     The squeezing motion changes the speed of the drum  130  in short cycle to move the laundry by repeatedly gathering and spreading the laundry. As the movement of the laundry is facilitated, washing deviation may be reduced and the laundry may be brought into uniform contact with the washing fluid. In addition, when the laundry clings to the inner circumferential surface of the drum  130 , the washing fluid soaked through the laundry may be discharged through the holes in the drum  130  as if being squeezed out of the laundry. Therefore, contaminants on the laundry may be discharged during washing as if being squeezed out, and wash agents remaining on the laundry may be discharged as if being squeezed out. Moreover, as the laundry is repeatedly drawn to and separated from the inner circumferential surface of the drum  130 , the user may visually check the movement of the laundry. 
     In certain embodiments, execution time of the squeezing motion during a wash cycle may be about 10 minutes. However, this may differ according to the amount of laundry being washing and/or a particular washing course selected. 
     In the squeezing motion, the washing fluid may be circulated to evenly soak the laundry. At the time of the squeezing motion, the pump  163  may be operated so that washing fluid discharged to the discharge hose  162  is circulated along the circulation path  164  and introduced into the drum  130  through the nozzle  165 . 
     It is then determined how many times N the general motion and the squeezing motion are repeated (S 470 ). The general motion and the squeezing motion may be performed N times so as to reduce/eliminate washing deviation by virtue of the movement of the laundry. The number of times N the general motion and squeezing motion are repeated may be varied according to a selected course and an amount of laundry. 
     After the general motion and the squeezing motion are repeated N times, simple spinning is performed (S 490 ) so that the washing fluid used in washing may be discharged to an outside of the washing machine. 
     If the amount of laundry in the drum  130  is within the set range (S 440 ), the general motion is performed (S 480 ), and the simple spinning is performed (S 490 ). 
     If the above-described process leading up to the simple spinning step S 490  is a general wash cycle, after simple spinning (S 490 ), the supply step (S 420 ) may be performed again to initiate a rinse cycle. The washing fluid supplied at this time may be water or water mixed with a fabric softener or the like. 
     In certain embodiments, execution time of the squeezing motion during the rinse cycle may be about 3 minutes. However, this may differ according to the amount of laundry in the drum  130  and/or a particular washing course selected. The above-described steps may be repeated in the rinse cycle. However, the operation time of each step and the repeated number of times N may be changed as appropriate. 
       FIG. 6  is a graph of rotation speed of the drum with respect to time in the washing method according to the exemplary embodiment as broadly described herein. In particular,  FIG. 6  illustrates an example in which a general motion is a tumbling motion. In such a general motion, the drum  130  may continuously rotate at about 45 rpm. In the squeezing motion, the speed of the drum  130  may be changed in short cycle within a speed range of about 50 to 100 rpm. 
     Cycle time in which acceleration and deceleration are repeated may be between about 1 to 4 seconds. Time to accelerate from 50 rpm to 100 rpm may be 2 seconds, and, in certain embodiments, about 1.2 seconds. Time to decelerate from 100 rpm to 50 rpm may be about 1 second and, in certain embodiments, about 0.5 seconds. 
     In the wash cycle or the rinse cycle, the general motion and the squeezing motion may be repeated as appropriate. 
     It will be understood by those skilled in the art that example embodiments can be implemented in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be noted that the forgoing embodiments are merely illustrative in all aspects and are not to be construed as limiting the invention. The scope of the invention is defined by the appended claims rather than the detailed description of the invention. All changes or modifications or their equivalents made within the meanings and scope of the claims should be construed as falling within the scope of the invention. 
     In a washing machine and washing method as embodied and broadly described herein, in the washing or rinsing of a large amount of laundry, the laundry is brought into good, uniform contact with washing fluid, thereby improving washing performance. 
     In a washing machine and washing method as embodied and broadly described herein, the movement of laundry is facilitated, thereby reducing washing deviation in the washing or rinsing of a large amount of laundry. 
     In a washing machine and washing method as embodied and broadly described herein, contaminants on the laundry may be discharged as if being squeezed out, thereby improving washing performance. 
     In a washing machine and washing method as embodied and broadly described herein, detergent remaining on the laundry may be discharged as if being squeezed out, thereby improving rinsing performance. 
     In a washing machine and washing method as embodied and broadly described herein, a user may visually check the movement of the laundry. 
     A washing machine and associated washing method which can improve washing performance are provided. 
     A washing machine and associated washing method which can uniformly mix laundry during a wash cycle or a rinse cycle are provided. 
     A washing machine and associated washing method which can allow laundry to be brought into uniform contact with washing water during a wash cycle or a rinse cycle are provided. 
     A washing method according to an exemplary embodiment as broadly described herein may include supplying washing water into a drum containing laundry; repeatedly dropping the laundry while rotating the drum in a predetermined direction; and sticking or separating the laundry to and from the inside of the drum by repeatedly accelerating and decelerating the drum. 
     A washing method according to another exemplary embodiment as broadly described herein may include rotating a drum to cause the laundry in the drum to be rotated, clinging to the inside of the drum, in a wash cycle or rinse cycle of a drum type washing machine; decelerating the drum to separate the laundry from the inside of the drum; and accelerating the drum to cause the laundry to be rotated, clinging to the inside of the drum. 
     A washing machine according to an exemplary embodiment as broadly described herein may include a drum which holds laundry and rotates; a drive unit for rotating the drum; and a control unit for performing a general motion in which the drive unit repeatedly drops the laundry by rotating the drum in a predetermined direction in a wash cycle or rinse cycle and a squeezing motion in which the drive unit sticks and separates the laundry to and from the inside of the drum by accelerating and decelerating the drum. 
     Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments. 
     Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, numerous variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.