Washing machine and control method thereof

Abstract

A washing machine provided with a structure thereof capable of draining and circulating by using a single pump and capable of enhancing washing performance by using a circulation of water and a rotation of a drum, and a control method thereof, in which the structure of the washing machine is simplified through the change of the flow path that enables the draining and the circulation of water by using a general pump while decreasing the number of the components of the washing machine. The manufacturing cost of the washing machine is reduced, because the washing machine accelerates the dissolution of detergent by generating large amount of bubbles by using the circulation of water and the rotation of the drum, without additional components, thereby washing performance of the washing machine is enhanced, and by maintaining the bubbles that are generated, the non-tangible quality that a user feels in the course of washing is enhanced.

What is claimed is: 
     
         1 . A method of controlling a washing machine provided with a tub, a drum rotatably installed inside the tub, and a pump configured to circulate water in the tub, the method comprising:
 (a) rotating the drum toward one direction for a first period of time after supplying washing water to the tub;   (b) stopping the drum for a second period of time after rotating the drum toward the one direction;   (c) rotating the drum toward an opposite direction opposite to the one direction for a third period of time after the second period of time is expired; and   (d) stopping the drum for a fourth period of time after rotating the drum toward the opposite direction,   wherein during a forward/backward alternate operation of the drum comprising (a) to (d), a bubble generating cycle to generate bubbles through rotation of the drum and friction of the circulated water is performed by driving the pump.   
     
     
         2 . The method of  claim 1 , wherein:
 the bubble generating cycle is performed after a water supplying cycle in which water and detergent are supplied to the tub to perform a washing.   
     
     
         3 . The method of  claim 1 , further comprising:
 a washing motor configured to rotate the drum,   wherein during the rotating of the drum toward the one direction, the washing motor is driven toward a normal direction for the first period of time while maintaining at a predetermined revolutions per minute (RPM).   
     
     
         4 . The method of  claim 3 , wherein:
 during the rotating of the drum toward the opposite direction, the washing motor is driven toward a reverse direction for the third period of time while maintaining at a predetermined RPM.   
     
     
         5 . The method of  claim 4 , wherein:
 the first period of time is same as the third period of time.   
     
     
         6 . The method of  claim 5 , wherein:
 the second period of time is same as the fourth period of time.   
     
     
         7 . The method of  claim 6 , wherein:
 the second period of time is set to be shorter than the first period of time.   
     
     
         8 . The method of  claim 7 , wherein:
 the first period of time is about 14 seconds.   
     
     
         9 . The method of  claim 7 , wherein:
 the second period of time is about 6 seconds.   
     
     
         10 . The method of  claim 4 , wherein:
 the first period of time is different from the third period of time.   
     
     
         11 . The method of  claim 4 , wherein:
 the second period of time is different from the fourth period of time.   
     
     
         12 . The method of  claim 4 , wherein:
 during the forward/backward alternate operation of the drum, the predetermined RPM is 80 RPM or above.   
     
     
         13 . The method of  claim 4 , further comprising:
 during the forward/backward alternate operation of the drum, changing the RPM of the motor.   
     
     
         14 . The method of  claim 1 , further comprising:
 during the forward/backward alternate operation of the drum, changing a driving time of the motor or a stopping time of the motor.   
     
     
         15 . The method of  claim 1 , wherein:
 the forward/backward alternate operation of the drum comprising from (a) to (d) is performed for a predetermined period of time.   
     
     
         16 . The method of  claim 1 , further comprising:
 counting the number of proceedings of the bubble generating cycle, wherein if the counted number of proceedings of the bubble generating cycle reaches to a predetermined reference number of proceedings, the bubble generating cycle is finished.   
     
     
         17 . The method of  claim 16 , wherein:
 the predetermined reference number of proceedings is determined by considering a washing time at each washing cycle.   
     
     
         18 . A washing machine, comprising:
 a tub to accommodate water;   a drum rotatably installed inside the tub;   a washing motor configured to rotate the drum;   a flow path switching apparatus configured to switch a flow path of water such that water in the tub is drained or circulated; and   a control unit, after water and detergent are supplied to the tub, configured to perform a bubble generating cycle in which water in the tub is circulated by controlling the flow path switching apparatus and the drum is alternately rotated forward and backward by controlling the washing motor.   
     
     
         19 . The washing machine of  claim 18 , wherein:
 the control unit, during the forward and backward alternate rotation of the drum, is configured to drive the washing motor at a predetermined revolutions per minute (RPM) and a predetermined driving factor.   
     
     
         20 . The washing machine of  claim 19 , wherein:
 the control unit is configured to alternately rotate the drum while having the RPM of the motor at 80 RPM or above.   
     
     
         21 . The washing machine of  claim 20 , wherein:
 the control unit, during the forward/backward alternate rotation of the drum, is configured to change the RPM of the motor.   
     
     
         22 . The washing machine of  claim 20 , wherein:
 the control unit, during the forward/backward alternate rotation of the drum, is configured to change the driving factor of the motor.   
     
     
         23 . The washing machine of  claim 18 , wherein:
 the control unit is configured to count a time that the forward/backward alternate rotation of the drum is performed, and to stop the forward/backward alternate rotation of the drum if the counted time reaches to a predetermined period of time.   
     
     
         24 . The washing machine of  claim 18 , wherein:
 the flow path switching apparatus comprises a pump configured to pump the water in the tub, and a flow path switching valve configured to switch a flow path such that water being discharged from the tub is drained to an outside or the water is circulated to the tub.   
     
     
         25 . A method of controlling a washing machine provided with a tub, a drum rotatably installed inside the tub, a washing motor to rotate the drum, and a pump configured to circulate water in the tub, the method comprising:
 supplying water and detergent to the tub;   performing a bubble generating cycle, in which water being discharged from the tub is circulated to the tub by driving the pump at the same time of alternately rotating the drum forward and backward by driving the washing motor at a predetermined revolutions per minute (RPM) and a predetermined driving factor; and   performing a washing cycle, in which the drum alternately rotates forward and backward, by driving the washing motor at a target RPM and a target driving factor,   wherein a proceeding time of the bubble generating cycle and a proceeding time of the washing cycle are counted, and if the counted proceeding time of the bubble generating cycle and the counted proceeding time of the washing cycle pass over a predetermined period of time, the bubble generating cycle and the washing cycle are alternately performed with each other.   
     
     
         26 . The method of  claim 25 , wherein the bubble generating cycle comprises:
 rotating the drum toward one direction for a first period of time;   stopping the drum for a second period of time after rotating the drum toward the one direction;   rotating the drum toward an opposite direction for the first period of time after the second period of time is expired; and   stopping the drum for the second period of time after rotating the drum toward the opposite direction.   
     
     
         27 . The method of  claim 25 , wherein:
 the bubble generating cycle comprises generating bubbles through rotation of the drum and friction of the circulated water by driving the pump during the forward and backward alternate rotation of the drum.   
     
     
         28 . The method of  claim 26 , wherein:
 the bubble generating cycle comprises driving the washing motor toward a normal direction or toward a reverse direction for the first period of time while maintaining the washing motor at the predetermined RPM during the forward and backward alternate rotation of the drum.   
     
     
         29 . The method of  claim 25 , wherein:
 the predetermined RPM of the washing motor of the bubble generating cycle is set to be higher than the target RPM of the washing motor of the washing cycle.   
     
     
         30 . The method of  claim 25 , wherein:
 a proceeding time of the bubble generating cycle is set to be shorter than a proceeding time of the washing cycle.   
     
     
         31 . The method of  claim 25 , further comprising:
 counting the number of proceedings of the bubble generating cycle, and   finishing the bubble generating cycle when the counted number of the proceedings reaches to a predetermined reference number of proceedings.   
     
     
         32 . The method of  claim 31 , further comprising:
 only performing the washing cycle during a remaining washing time after the finishing of the bubble generating cycle.   
     
     
         33 . The method of  claim 31 , wherein:
 the predetermined reference number of proceedings is at least twice.   
     
     
         34 . A method of controlling a washing machine provided with a tub, a drum rotatably installed inside the tub, a pump to pump water in the tub, and a flow path switching valve configured to switch a flow path to drain or circulate the water in the tub, the method comprising:
 determining whether a current cycle is a washing cycle;   switching the flow path so that water being discharged from the tub is introduced to the tub by driving the flow path switching valve if determined as the washing cycle;   introducing the water being discharged from the tub by driving the pump to the tub; and   performing a bubble generating cycle to generate bubbles through friction of the water introduced to the tub and the drum by rotating the drum.