Balancer and drum washing machine having the same

摘要

Disclosed is a drum washing machine having ball balancers (50) for rapidly reducing the vibration of a drum (30). The drum washing machine includes a drum rotatably installed so as to wash or dehydrate laundry; and balancers (50), each including a plurality of masses (51); a housing provided with a race (54) having a rectangular section, on which the masses move in a circumferential direction; and a fluid filling the inside of the race for reducing noise caused by the circumferential movement of the masses. The race has a rectangular section, corner portions (54a) of which are rounded, and a value obtained by dividing the radius of the corner portions by the radius of the masses is between 0.4 and 0.9 so as to effectively reduce the vibration of the drum. The drum washing machine effectively reduces the vibration of the drum while using a small amount of the fluid.