Design and modelling of an active balancing device for washing machines
Examensarbete för masterexamen
In this thesis the possibility of actively balancing the spin drum in a washing machine is examined. Due to the fact that the unbalance in washing machines is highly variable, e.g. by water leaving the laundry during spin drying, active balancing is required where the balancing system continuously is changing according to how much unbalance there is to counterbalance. The idea is to use a concept which with the help of an eccentric mechanism displaces the spin drum during spin drying, thus counteract the unbalance which arises when the laundry has been unevenly distributed before spin drying. In the thesis a preliminary study in rotor dynamics has been done to examine what kind of different techniques there are for active balancing whereupon a development of other concepts to be compared to the eccentric mechanism was done. Primarily to find out if the concept already exists but also to examine if there are other concepts that could be comparable to or even better than the eccentric mechanism. The eccentric mechanism was considered to be the most potential concept. A design including the mechanical parts of the eccentric mechanism has been dimensioned to be able to use in a physical prototype and to make it possible to execute a spin drying speed of 2000 rpm without excessive vibrations. The eccentric mechanism was modelled in Pro/ENGINEER and its behaviour has been studied in a computerised model of ASKO Cylinda washing machine in ADAMS/View. Through analysis in the virtual model it was found that the model is comparable to a physical machine and the vibrations caused by the unbalance can be strongly reduced by the use of the eccentric mechanism.
Konstruktionsteknik , Construction engineering