Control method of laundry machine

Abstract

A control method of a laundry machine is disclosed. The control method of laundry machine having a drum, a front balancer provided with a front portion of the drum and a rear balancer provided with a rear portion of the drum includes accelerating the drum and rotating the drum at a constant speed of a predetermined rotation speed for a predetermined time period, the predetermined rotation speed allowing that perpendicular displacement at the front portion of the drum is different from that at the rear portion of the drum.

1 . A control method of laundry machine having a drum, a front balancer provided with a front portion of the drum and a rear balancer provided with a rear portion of the drum, the control method comprising:
 accelerating the drum and rotating the drum at a constant speed of a predetermined rotation speed for a predetermined time period, the predetermined rotation speed allowing that perpendicular displacement at the front portion of the drum is different from that at the rear portion of the drum.   
     
     
         2 . The control method as claimed in  claim 1 , wherein the predetermined rotation speed is included in the transient region. 
     
     
         3 . The control method as claimed in  claim 1 , wherein perpendicular displacement at the front portion of the drum with respect to a rotational shaft of a transient region is contrary to that at the rear portion of the drum at the predetermined rotation speed. 
     
     
         4 . The control method as claimed in  claim 1 , wherein the control method further comprising:
 a first transient region step for entering a transient region by accelerating the drum;   a third constant speed rotation step for rotating the drum at a constant speed of a third rotation speed for a first predetermined time, the third rotation speed allowing that perpendicular displacement at the front portion of the drum with respect to a rotational shaft of the transient region is contrary to that at the rear portion of the drum; and   a second transient region step for straying from the transient region by accelerating the drum at the third rotation speed or more.   
     
     
         5 . The control method as claimed in  claim 4 , wherein the second transient region step includes a rotation speed allowing a natural vibration mode where perpendicular displacement to the rotational shaft of the drum at the front portion of the drum is contrary to that at the rear portion of the drum. 
     
     
         6 . The control method as claimed in  claim 5 , wherein the first predetermined time of the third constant speed rotation step is determined such that an angle between the front balls and front unbalance of the drum is 90° or more and an angle between the rear balls and rear unbalance of the drum is 90° or more. 
     
     
         7 . The control method as claimed in  claim 6 , wherein the first predetermined time of the third constant speed rotation step is determined such that an angle between a centrifugal force center of the front balls and the front unbalance is 180° and an angle between a centrifugal force center of the rear balls and the rear unbalance is 180°. 
     
     
         8 . The control method as claimed in  claim 7 , wherein the first predetermined time of the third constant speed rotation step is determined such that the angle between the centrifugal force center of the front balls and the front unbalance and the angle between a centrifugal force center of the rear balls and the rear unbalance are uniformly maintained, respectively. 
     
     
         9 . The control method as claimed in  claim 6 , wherein, at the second transient region step, an angle between the centrifugal force center of the front balls and the centrifugal force center of the rear balls is 90° or more when viewed at the front portion of the drum. 
     
     
         10 . The control method as claimed in  claim 6 , wherein the third rotation speed of the third constant speed rotation step is maintained in the range of 250 rpm to 290 rpm. 
     
     
         11 . The control method as claimed in  claim 10 , wherein the third rotation speed of the third constant speed rotation step is maintained at 270 rpm. 
     
     
         12 . The control method as claimed in  claim 6 , wherein the third rotation speed allows the front balancer and the rear balancer to be subjected to balancing. 
     
     
         13 . The control method as claimed in  claim 12 , wherein the second transient region step has an acceleration inclination greater than that of the first transient region step. 
     
     
         14 . The control method as claimed in  claim 4 , further comprising the step of a fourth constant speed rotation step for rotating the drum at a constant speed of a fourth rotation speed for a second predetermined time after the second transient region step. 
     
     
         15 . The control method as claimed in  claim 14 , wherein the fourth rotation speed allows the drum to be vibrated such that perpendicular displacement to the rotational shaft of the drum at the front portion of the drum is equal to that at the rear portion of the drum. 
     
     
         16 . The control method as claimed in  claim 4 , wherein the first transient region step includes a rotation speed allowing a natural vibration mode where perpendicular displacement to the rotational shaft of the drum at the front portion of the drum is equal to that at the rear portion of the drum. 
     
     
         17 . The control method as claimed in  claim 16 , wherein, at the first transient region step, an angle between the centrifugal force center of the front balls and the centrifugal force center of the rear balls is within 90° when viewed at the front portion of the drum. 
     
     
         18 . The control method as claimed in  claim 4 , further comprising:
 a first constant speed rotation step for rotating the drum at a constant speed of a first rotation speed, sensing a first unbalance, and comparing the sensed first unbalance with a first allowable unbalance; and   a second constant speed rotation step for sensing a second unbalance at a second rotation speed of the drum greater than the first rotation speed and comparing the sensed second balance with a second allowable balance.   
     
     
         19 . A control method of a laundry machine having a drum, a front balancer provided with a front portion of the drum, and a rear balancer provided with a rear portions of the drum, the control method comprising:
 a first transient region step for passing through a rotation speed allowing a natural vibration mode where perpendicular displacement to a rotational shaft of the drum at the front portion of the drum is equal to that at the rear portion of the drum;   a constant speed rotation step for rotating the drum at a constant speed for a predetermined time after the first transient region step; and   a second transient region step for passing through a rotation speed allowing a natural vibration mode where perpendicular displacement to a rotational shaft of the drum at the front portion of the drum is contrary to that at the rear portion of the drum.   
     
     
         20 . The control method as claimed in  claim 1 , wherein the laundry machine comprises a driving unit comprising a shaft connected to a drum, a bearing housing to rotatably support the shaft, and a motor to rotate the shaft, and a suspension assembly is connected to the driving unit. 
     
     
         21 . The control method as claimed in  claim 1 , wherein the laundry machine comprises a rear gasket for sealing to prevent washing water from leaking from a space between a driving unit and a tub, and enabling the driving unit movable relative to the tub. 
     
     
         22 . The control method as claimed in  claim 1 , wherein a tub is supported rigidly more than a drum being supported by a suspension assembly. 
     
     
         23 . The control method as claimed in  claims 20 , wherein the front balancer and the rear balancer have 14 balls, respectively, each of the balls has a diameter of 18.55 mm to 19.55 mm, a race for receiving the balls includes a ball space portion having a sectional area in the range of 410 mm  2  to 413 mm  2 , and a center diameter of the sectional area of the ball space portion is in the range of 500 mm to 510 mm. 
     
     
         24 . The control method as claimed in  claim 20 , wherein each of the ball space portions of the front balancer and the rear balancer is filled with oil having viscosity of 300 cs at a filling level of 340 cc to 360 cc. 
     
     
         25 . The control method as claimed in  claim 7 , wherein the third rotation speed of the third constant speed rotation step is maintained in the range of 250 rpm to 290 rpm. 
     
     
         26 . The control method as claimed in  claim 8 , wherein the third rotation speed of the third constant speed rotation step is maintained in the range of 250 rpm to 290 rpm. 
     
     
         27 . The control method as claimed in  claim 9 , wherein the third rotation speed of the third constant speed rotation step is maintained in the range of 250 rpm to 290 rpm. 
     
     
         28 . The control method as claimed in  claim 7 , wherein the third rotation speed allows the front balancer and the rear balancer to be subjected to balancing. 
     
     
         29 . The control method as claimed in  claim 8 , wherein the third rotation speed allows the front balancer and the rear balancer to be subjected to balancing. 
     
     
         30 . The control method as claimed in  claim 9 , wherein the third rotation speed allows the front balancer and the rear balancer to be subjected to balancing. 
     
     
         31 . The control method as claimed in  claim 21 , wherein the front balancer and the rear balancer have 14 balls, respectively, each of the balls has a diameter of 18.55 mm to 19.55 mm, a race for receiving the balls includes a ball space portion having a sectional area in the range of 410 mm  2  to 413 mm  2 , and a center diameter of the sectional area of the ball space portion is in the range of 500 mm to 510 mm. 
     
     
         32 . The control method as claimed in  claim 22 , wherein the front balancer and the rear balancer have 14 balls, respectively, each of the balls has a diameter of 18.55 mm to 19.55 mm, a race for receiving the balls includes a ball space portion having a sectional area in the range of 410 mm  2  to 413 mm  2 , and a center diameter of the sectional area of the ball space portion is in the range of 500 mm to 510 mm. 
     
     
         33 . The control method as claimed in  claim 21 , wherein each of the ball space portions of the front balancer and the rear balancer is filled with oil having viscosity of 300 cs at a filling level of 340 cc to 360 cc. 
     
     
         34 . The control method as claimed in  claim 22 , wherein each of the ball space portions of the front balancer and the rear balancer is filled with oil having viscosity of 300 cs at a filling level of 340 cc to 360 cc.