Washing machine

Abstract

A washing machine including a fixed tank; a rotary drum accommodated in the fixed tank and into which laundry is loadable; a drain configured to discharge water collected in the fixed tank; a ball balancer installed in the rotary drum; a controller; and a driver configured to rotate the rotary drum, the driver including a shaft fixed to the rotary drum, and configured to be rotatable to rotate the rotary drum, a motor including a stator and a rotor, a reducer, and a clutch configured to be switched between a first mode in which rotation of the rotor is transmitted to the shaft through the reducer, and a second mode in which the rotation of the rotor is transmitted to the shaft without passing through the reducer.

1 . A washing machine comprising:
 a fixed tank;   a rotary drum accommodated in the fixed tank and into which laundry is loadable;   a drain configured to discharge water collected in the fixed tank;   a ball balancer installed in the rotary drum;   a controller; and   a driver configured to rotate the rotary drum, the driver including:
 a shaft fixed to the rotary drum, and configured to be rotatable to rotate the rotary drum, 
 a motor including a stator and a rotor, 
 a reducer, and 
 a clutch configured to be switched between:
 a first mode in which rotation of the rotor is transmitted to the shaft through the reducer, and 
 a second mode in which the rotation of the rotor is transmitted to the shaft without passing through the reducer. 
 
   
     
     
         2 . The washing machine of  claim 1 , wherein the controller is configured to:
 perform a first operation of setting the clutch to the first mode in a first process before a second process in which spin-drying is performed, and   control the motor in the first mode so that a rotation speed of the rotary drum is a first rotation speed higher than a predefined rotation speed that causes laundry inside the rotary drum to stick to an inner wall of the rotary drum.   
     
     
         3 . The washing machine of  claim 2 , wherein the controller is configured to:
 in the first operation, control the motor to have the first rotation speed and detect a vibration period of a vibration system including the rotary drum, the laundry inside the rotary drum, and the ball balancer.   
     
     
         4 . The washing machine of  claim 3 , wherein the controller is configured to:
 perform a second operation of controlling the motor so that the rotation speed of the rotary drum is higher than the first rotation speed and lower than a second rotation speed in a high-speed rotation period corresponding to a period excluding a maximum amplitude time point at which an amplitude of the vibration period of the vibration system detected during the first operation is maximum.   
     
     
         5 . The washing machine of  claim 3 , wherein the controller is configured to:
 perform the first operation until a second maximum amplitude time point following a first maximum amplitude time point at which an amplitude of the detected vibration period is maximum during the first operation.   
     
     
         6 . The washing machine of  claim 4 , wherein the controller is configured to:
 end the first operation and initiate the second operation when an end condition of the first operation is satisfied.   
     
     
         7 . The washing machine of  claim 6 , wherein
 the end condition of the first operation is determined according to the first rotation speed, and   a length of time before an end time of the first operation increases as the first rotation speed increases.   
     
     
         8 . The washing machine of  claim 4 , wherein
 the controller is configured to fix the rotation speed of the rotary drum to the second rotation speed while performing the second operation.   
     
     
         9 . The washing machine of  claim 8 , wherein
 the second rotation speed is a maximum rotation speed of the rotary drum, and is lower than a resonant rotation speed of the washing machine.   
     
     
         10 . The washing machine of  claim 4 , wherein the controller is configured to:
 estimate a next vibration period from the vibration period of the vibration system detected in the first operation, and   detect a high-speed rotation period excluding a start time and an end time from the estimated next vibration period.   
     
     
         11 . The washing machine of  claim 10 , wherein
 the controller is configured to perform the second operation during the high-speed rotation period.   
     
     
         12 . The washing machine of  claim 10 , wherein
 the controller is configured to estimate the next vibration period based on a difference between the rotation speed of the rotary drum in the first operation and the rotation speed of the rotary drum in the second operation.   
     
     
         13 . The washing machine of  claim 4 , wherein
 the controller is configured to end the second operation and initiate a spin-drying process when an end condition of the second operation is satisfied.   
     
     
         14 . The washing machine of  claim 13 , wherein
 the end condition of the second operation includes a condition that a predefined time elapses, and   the predefined time is determined by a load of the rotary drum.   
     
     
         15 . The washing machine of  claim 2 , wherein
 the controller is configured to:
 control the drain so that water collected in the fixed tank in the second process is discharged, 
 set the clutch to the second mode, and 
 control the motor so that the rotation speed of the rotary drum is higher than the first rotation speed. 
   
     
     
         16 . The washing machine of  claim 15 , wherein
 the rotation speed of the rotary drum in the second mode is a maximum rotation speed of the rotary drum.   
     
     
         17 . The washing machine of  claim 1 , wherein
 the controller is configured to:
 set the clutch to the first mode in a washing process before a second process in which spin-drying is performed, and 
 control the motor so that a rotation speed of the rotary drum is a washing rotation speed lower than a predefined rotation speed that causes laundry inside the rotary drum to stick to an inner wall of the rotary drum. 
   
     
     
         18 . The washing machine of  claim 17 , wherein
 the controller is configured to set the clutch to the second mode in the second process in which the spin-drying is performed,   torque of the motor in the second mode is lower than the torque of the motor in the first mode, and   the rotary drum rotates at a same speed as the motor in the second mode.   
     
     
         19 . The washing machine of  claim 1 , wherein the controller is configured to:
 set the clutch to the first mode to rotate the rotary drum in a detangling process before a second process in which spin-drying is performed, so that a load caused by laundry inside the rotary drum is reduced, and   set the clutch to the second mode in the second process.   
     
     
         20 . The washing machine of  claim 1 , wherein
 the clutch includes a clutch that is moved by a magnetic field of a clutch coil or a clutch that is moved by an operation of a mechanical actuator.