Design and Analysis for a Drum Type Washing Machine with a Fixed Tub Structure

This paper presents the design and analysis processes for a drum type washer that can achieve the biggest capacity within limited installation space using a fixed-tub structure. Among limitations against increasing the capacity of a conventional drum type washer, a certain amount of space which is necessary to avoid collision between the outer tub and the cabinet, while passing through the resonance region, is effectively minimized by adapting a fixed-tub structure. In the designing phase, strength analysis and modal analysis are carried out to assure the safety of the proposed structure. Automatic ball balancers are designed and applied to mitigate the steady-state vibration of the drum. Along with ball balancers, a rubber gasket is designed and its stiffness is also analytically optimized to insulate transmitted forces into base structures. Comparing conventional drum type washers, the newly designed fixed-tub washer can increase its capacity by over 20% and its vibration on hard floors is diminished by more than 50%.