Patent ID: 9528213
Filing Date: 2016-12-27
CPC Classification: B23P,D06F,H02K,Y02B,Y10T

Claim Text:
1. A washing machine comprising: a cabinet defining an outer appearance; a tub disposed within the cabinet; a main drum rotatably mounted in the tub; a sub drum mounted in the main drum to be relatively rotatable with respect to the main drum; an outer shaft for rotating the main drum; an inner shaft for rotating the sub drum upon, being disposed inside the outer shaft; a driving motor having a stator, an outer rotor connected to the inner shaft and rotatable outside the stator, and an inner rotor connected to the outer shaft and rotatable inside the stator, wherein the stator is formed with an inner stator facing the inner rotor and an outer stator facing the outer rotor; and an insulator configured to form the inner stator and the outer stator integrally, wherein a ratio of a outer diameter of the inner rotor with respect to an outer diameter of the inner stator is in the range of 0.7˜0.8.