Patent ID: 8820124

Claim:
A drum type washing machine comprising: a housing; a spin tub rotatable by receiving rotational force from a driving motor through a rotating shaft, the spin tub including a spin tub body having a cylindrical structure formed with a plurality of pores allowing water to pass through the spin tub, the spin tub body having a front section with a laundry receiving opening provided and a rear section opposite to the front section; a rear balancer installed at the rear section of the spin tub to reduce a dynamic imbalance during rotation thereof, the rear balancer including an annular-shaped race having a closed internal space in which a plurality of balls and viscous fluid are accommodated, the annular-shaped race including a first annular-shaped member and a second annular-shaped member joined to each other to define the closed internal space, the first annular-shaped member including a first side wall, a second side wall and a connecting wall between the first side wall and the second side wall, the first annular-shaped member having an open side opposite to the connecting wall, and the second annular-shaped member being adapted to cover the open side of the first annular-shaped member; and a shaft flange including a hub section to fixedly install the rotating shaft and a plurality of arm sections extending radially outward from the hub section and mounted to the spin tub so as to transfer the rotational force to the spin tub, each of the plurality of arm sections having a mounting groove opened toward the rear section of the spin tub to accommodate at least one portion of the rear balancer.