Washing machine and method of controlling the same

Abstract

The present invention relates to a washing machine configured to have a drum, into which cloth is loaded, that is rotated around a horizontal axis. The washing machine includes a plurality of protrusions which are extended in a front and rear direction on an inner circumferential surface of the drum, and are spaced along a circumferential direction, and the protrusion has a height protruding inwardly into the drum is 2.0 to 6.0% of a diameter of the drum.

1 . A washing machine comprising: a drum having an elongated cylindrical shape and providing a space into which laundry;
 a motor configured to rotate the drum; and   a plurality of lifter which are extended along a longitudinal direction of the drum on an inner circumferential surface of the drum and are spaced apart from each other in a circumferential direction of the drum, wherein the lifter protrudes from the inner circumferential surface of the drum and has a height of 2.0% to 6.0% of a diameter of the drum, and   a protrusion structure higher than any one of the plurality of lifters does not exist, between a pair of adjacent lifters among the plurality of protrusions, on the inner circumferential surface of the drum.   
     
     
         2 . The washing machine of  claim 1 , wherein the drum further comprises a plurality of embossing, on the inner circumferential surface, formed to be lower than any of the plurality of lifters, and
 wherein a protrusion structure does not exist excluding the plurality of embossings, between the pair of adjacent protrusions arbitrarily selected from among the plurality of protrusions, on the inner circumferential surface of the drum.   
     
     
         3 . The washing machine of  claim 2 , wherein a height of the embossing is 5 mm or less. 
     
     
         4 . The washing machine of  claim 1 , wherein the lifter comprises a first side surface and a second side surface extending in a longitudinal direction of the lifter,
 wherein a first angle is an angle between the first side surface and a portion of the drum, the portion of the drum is positioned between the first side surface and the second side surface,   wherein a second angle is an angle between the second side surface and the portion of the drum,   wherein at least one of the first angle and the second angle is 17.5 degrees or more.   
     
     
         5 . The washing machine of  claim 1 , wherein a length from a front end to a rear end of the lifter is 50 to 100% of a length of the drum. 
     
     
         6 . The washing machine of  claim 5 , wherein the drum has a front end band portion and a rear end band portion that are flat and formed in a front end and a rear end, respectively,
 wherein the lifter is disposed between the front end band portion and the rear end band portion.   
     
     
         7 . The washing machine of  claim 1 , wherein the lifter is formed integrally with the drum. 
     
     
         8 . The washing machine of  claim 7 , wherein the drum is manufactured by processing a metal sheet of stainless steel, and has a thickness of 0.4 to 0.6 mm. 
     
     
         9 . The washing machine of  claim 1 , wherein the drum is formed of stainless steel, and the lifter is made of synthetic resin and coupled with the drum. 
     
     
         10 . The washing machine of  claim 1 , wherein the lifter has a height of 10 mm to 30 mm. 
     
     
         11 . The washing machine of  claim 1 , wherein the drum is configured to rotate one or more revolutions in one direction at a set speed between 60 to 90 rpm such that the cloth is lifted to a certain height by the lifter and then dropped at least once. 
     
     
         12 . The washing machine of  claim 11 , wherein the set speed is set such that the cloth in the drum is lifted to an angle of 90 degrees or less in a rotational direction of the drum from a lowest point of the drum and then dropped. 
     
     
         13 . The washing machine of  claim 11 , wherein the set speed is set such that the cloth in the drum is lifted to an angle of 90 degrees or more and 180 degrees or less in a rotational direction of the drum from a lowest point of the drum and then dropped. 
     
     
         14 . The washing machine of  claim 1 , further comprising a controller configured to control a rotation of the motor.