Washing machine and control method thereof

Abstract

A washing machine includes a drum, a water supply device, and a controller. The drum accommodates laundry, and the water supply device supplies water to the inside of the drum. The controller controls supply of water so that water is supplied into the drum from when rotational speed of the drum reaches a first predetermined speed, is decelerated and reaches a second predetermined speed, to when the rotational speed of the drum reaches to a third speed more than the second speed and less than the first speed, in a spin-drying cycle.

What is claimed is: 
     
         1 . A washing machine comprising:
 a drum accommodating laundry;   a water supply device supplying water to the inside of the drum; and   a controller controlling supply of water so that water is supplied into the drum from when the rotational speed of the drum reaches a first predetermined speed, to when the rotational speed of the drum is decelerated, reaches a second predetermined speed and then reaches a third speed more than the second speed and less than the first speed, in a spin-drying cycle.   
     
     
         2 . The washing machine according to  claim 1 , wherein the water supply device includes:
 an injection nozzle injecting water into the drum; and   a water supply valve adjusting supply of water from the outside of the washing machine to the injection nozzle.   
     
     
         3 . The washing machine according to  claim 2 , wherein the first speed is a rotational speed greater than the second speed, and the second speed is a resonant speed. 
     
     
         4 . The washing machine according to  claim 3 , wherein the controller adjusts at least one of an opening and closing time and an opening and closing degree of the water supply valve. 
     
     
         5 . The washing machine according to  claim 3 , wherein the controller stops injection of water into the drum by closing the water supply valve if the rotational acceleration of the drum is greater than a predetermined acceleration while the rotational speed of the drum reaches the second speed and then reaches the third speed. 
     
     
         6 . The washing machine according to  claim 2 , wherein the controller causes water to be supplied to the inside of the drum until the rotational speed of the drum reaches the second speed, maintains the second speed and then reaches the third speed. 
     
     
         7 . The washing machine according to  claim 6 , wherein the first speed is a rotational speed greater than the second speed, and the second speed is a rotational speed smaller than a resonant speed. 
     
     
         8 . The washing machine according to  claim 7 , wherein the controller adjusts at least one of an opening and closing time and an opening and closing degree of the water supply valve. 
     
     
         9 . The washing machine according to  claim 8 , wherein the controller stops injection of water into the drum by closing the water supply valve if the rotational acceleration of the drum is greater than a predetermined acceleration while the rotational speed of the drum reaches the second speed and then reaches the third speed. 
     
     
         10 . A control method of a washing machine comprising:
 injecting water into a drum accommodating laundry using an injection nozzle from when the rotational speed of the drum reaches a first predetermined speed in a spin-drying cycle; and   stopping injection of water into the drum when the rotational speed of the drum is decelerated and reaches a second predetermined speed and then the rotational speed of the drum reaches to a third speed more than the second speed and less than the first speed.   
     
     
         11 . The control method according to  claim 10 , wherein the first speed is a rotational speed greater than the second speed, and the second speed is a resonant speed. 
     
     
         12 . The control method according to  claim 11 , wherein the injection of water into the drum using the injection nozzle includes injecting water into the drum by adjusting at least one of an opening and closing time and an opening and closing degree of a water supply valve adjusting supply of water to the injection nozzle. 
     
     
         13 . The control method according to  claim 11 , wherein the stoppage of injection of water into the drum includes stopping injection of water into the drum if the rotational acceleration of the drum is greater than a predetermined acceleration while the rotational speed of the drum reaches the second speed and then reaches the third speed. 
     
     
         14 . The control method according to  claim 10 , wherein the stoppage of injection of water into the drum includes stopping injection of water into the drum when the rotational speed of the drum reaches the second speed, maintains the second speed and then reaches the third speed. 
     
     
         15 . The control method according to  claim 14 , wherein the first speed is a rotational speed greater than the second speed, and the second speed is a rotational speed smaller than a resonant speed. 
     
     
         16 . The control method according to  claim 15 , wherein the injection of water into the drum using the injection nozzle includes injecting water into the drum by adjusting at least one of an opening and closing time and an opening and closing degree of a water supply valve adjusting supply of water to the injection nozzle. 
     
     
         17 . The control method according to  claim 15 , wherein the stoppage of injection of water into the drum includes stopping injection of water into the drum if the rotational acceleration of the drum is greater than a predetermined acceleration while the rotational speed of the drum reaches the second speed, maintains the second speed and then reaches the third speed. 
     
     
         18 . A control method of a washing machine, comprising:
 draining water from a tub to outside the washing machine;   driving a drum of the washing machine at an accelerated speed;   sensing an RPM of the drum;   judging whether or not the rotational speed of the drum reaches a first reference speed, and stop driving the drum upon judging that the rotational speed of the drum reaches the first predetermined reference speed;   during deceleration of the drum after stopping the driving of the drum, begin injecting water into the drum;   re-driving the drum motor to a second reference speed;   judging whether or not the rotational acceleration of the drum is greater than a predetermined reference acceleration;   upon judging that the rotational acceleration of the drum is greater than the predetermined reference acceleration, stopping injection of water into the drum;   accelerating the drum to a maximum speed; and   stopping the driving of the drum.   
     
     
         19 . the control method according to  claim 18 , wherein the first predetermined reference speed is greater than a resonant speed of the washing machine. 
     
     
         20 . the control method according to  claim 19 , where the resonant speed is a rotational speed of the drum at the moment when vibration is rapidly generated due to properties of the washing machine. 
     
     
         21 . The control method according  claim 20 , wherein the second reference speed is the resonant speed. 
     
     
         22 . The control method according  claim 18 , wherein injecting water into the drum comprises injecting water into the drum for a designated time. 
     
     
         23 . The control method according  claim 22 , wherein the designated time is about 20 seconds. 
     
     
         24 . The control method according  claim 18 , wherein injecting water into the drum comprises injecting a designated amount of water into the drum. 
     
     
         25 . The control method according  claim 18 , wherein the predetermined reference acceleration is 6 rpm/s.