Patent ID: 8621896

Claim:
A washing machine, comprising: a tub that receives washing fluid therein; a drum rotatably installed in the tub; a shaft that penetrates the tub and is connected to the drum, wherein the shaft transmits a driving force generated by a motor to the drum; a stator positioned on and fixed to a rear wall of the tub; and an outer rotor including a rotor frame rotatably positioned outside the stator, a plurality of magnets, and an annular back yoke that defines a magnetic path, wherein the rotor frame is made of a die cast aluminum material, and wherein the rotor frame comprises: a side wall portion that supports the plurality of magnets and the annular back yoke; and a rear wall portion formed integrally with the side wall portion, wherein the rear wall portion transmits a rotating force of the outer rotor to the shaft, and wherein the back yoke includes a plurality of recesses or protrusions formed at an outer circumferential surface thereof, and the side wall portion of the rotor frame includes a plurality of protrusions or recesses formed at an inner circumferential surface thereof, respectively corresponding to the plurality of recesses or protrusions formed at the outer circumferential surface of the back yoke such that the back yoke is coupled within the side wall portion of the rotor frame by engagement between the plurality of protrusions or recesses of the side wall portion and the plurality of recesses or protrusions of the back yoke, respectively, wherein the plurality of magnet is attached to an inner circumferential surface of the back yoke by an adhesive and is arranged in a circumferential direction of the back yoke.