Method for controlling dehydration or water removal in drum washing machine

Abstract

A method for controlling dehydration or water removal in a drum washing machine, which repetitively measures an unbalance value at different speeds during balance spin-drying for spreading laundry items before main spin-drying is performed in a drum washing machine, and senses an unbalance for forward and backward directions of a drum as well as an unbalance for the rotational direction of the drum so that the laundry items are redistributed in a relatively normal manner. Thus, since vibrations of the tub may be reduced during the spin-drying process, the spin-drying efficiency may be improved.

1 . A method for controlling dehydration or water removal in a drum washing machine, comprising:
 agitating and balance spin-drying laundry in a drum of the washing machine, then accelerating a motor of the washing machine to a laundry adherence speed;   detecting a first unbalance value when the motor reaches the laundry adherence speed;   accelerating the motor to a water removal speed according to the first unbalance value;   detecting a second unbalance value when the motor reaches the water removal speed to obtain a comparison result; and   comparing the first unbalance value and the second unbalance value, and performing main spin-drying according to a comparison result.   
     
     
         2 . The method of  claim 1 , wherein:
 when the first unbalance value is less than a preset value, the motor is accelerated to the water removal speed, and   when the first unbalance value is equal to or greater than the preset value, the method continues or repeats balance spin-drying.   
     
     
         3 . The method of  claim 1 , wherein, after detecting the second unbalance value,
 when the first unbalance value is equal to or less than the second unbalance value, main spin-drying is performed, and   when the first unbalance value is greater than the second unbalance value, the method repeats balance spin-drying.   
     
     
         4 . The method of  claim 1 , wherein detecting the second unbalance value comprises detecting a variation between forward and backward motions of a tub of the washing machine. 
     
     
         5 . The method of  claim 4 , wherein, after detecting the variation between the forward and backward motions of the tub,
 when the variation between the forward and backward motions of the tub is less than a preset variation, main spin-drying is performed, and   when the variation between the forward and backward motions of the tub is equal to or greater than the preset variation, the method repeats balance spin-drying.   
     
     
         6 . The method of  claim 4 , wherein the variation between the forward and backward motions of the tub is measured using a distance from the tub by a distance measurement sensor on a rear surface of a front panel of the washing machine. 
     
     
         7 . The method of  claim 4 , wherein the variation between the forward and backward motions of the tub is measured using a distance from a magnet attached to the tub by a Hall sensor on a rear surface of a front panel. 
     
     
         8 . A method for controlling dehydration or water removal in a drum washing machine, comprising:
 balance spin-drying laundry in a drum of the washing machine, then accelerating a motor of the washing machine to a laundry adherence speed;   detecting a first unbalance value when the motor reaches the laundry adherence speed;   accelerating the motor to a water removal speed when the first unbalance value is less than or equal to a preset value, and repeating balance spin-drying when the first unbalance value is greater than the preset value;   detecting a second unbalance value when the motor reaches the water removal speed; and   performing main spin-drying when the second unbalance value is less than or equal to a preset variation, and repeating balance spin-drying when the second unbalance value is greater than the preset variation.   
     
     
         9 . The method of  claim 8 , wherein detecting the second unbalance value comprises measuring a variation in a distance of a tub of the washing machine from a distance measurement sensor on a rear surface of a front panel of the washing machine. 
     
     
         10 . The method of  claim 8 , wherein detecting the second unbalance value comprises measuring a variation in a distance of a magnet attached to a tub of the washing machine from a Hall sensor on a rear surface of a front panel of the washing machine. 
     
     
         11 . The method of  claim 8 , wherein the laundry adherence speed is 50-150 RPM. 
     
     
         12 . The method of  claim 8 , wherein the water removal speed is greater than the laundry adherence speed. 
     
     
         13 . The method of  claim 8 , wherein the water removal speed is 125-250 RPM. 
     
     
         14 . A control circuit for a drum washing machine, comprising:
 a load cell sensor configured to sense a weight of laundry in a drum of the drum washing machine,   a water level sensor configured to sense a level of wash water in the tub,   a microcomputer, microcontroller or other logic circuit configured to receive values from the load cell sensor and the water level sensor, and control operations of the drum washing machine,   a motor driving controller configured to control a motor that rotates the drum, and   a distance measurement sensor configured to detect forward and backward motions of the tub.   
     
     
         15 . The control circuit of  claim 14 , further comprising a water supply controller configured to control the operation of a water supply valve according to a water supply control signal from the microcomputer, microcontroller or other logic circuit. 
     
     
         16 . The control circuit of  claim 14 , further comprising a drain controller configured to control the operations of a drain valve and/or a drain motor of the drum washing machine, according to a drain control signal from the microcomputer, microcontroller or other logic circuit. 
     
     
         17 . The control circuit of  claim 14 , wherein the motor driving controller controls the motor according to a motor control signal from the microcomputer, microcontroller or other logic circuit. 
     
     
         18 . A drum washing machine, comprising:
 the control circuit of  claim 14 ,   the tub,   the drum, horizontally rotatable in the tub, and having a number of holes in its circumference, and   the motor.   
     
     
         19 . The drum washing machine of  claim 18 , further comprising a washing heater that heats wash water according to a control signal from the microcomputer, microcontroller or other logic circuit. 
     
     
         20 . The drum washing machine of  claim 18 , further comprising a plurality of dampers and a plurality of springs configured to reduce vibrations of the tub.