Reduction in vibration of a washing machine by means of a disengaging damper

• The electromechanical damper for a washing machine was designed.
• The structure of the damper and the controlling unit are very simple.
• The damper can be applied in a rotating machine operating above resonance.
• The dynamic model is presented to validate the concept of vibration reduction.
• Numerical simulations and experimental measurements were carried out and compared.

This paper presents a new semi-active technique for reducing the vibration of a washing machine frame during the spin cycle. A new electromechanical damper was proposed for this purpose. The damper is disengaged during the spin cycle, which results in the reduction of the vibration of the frame. A unit for switching the state (on/off) of the damper is presented. A dynamic model of the washing unit was developed to simulate the motion of the system after the damping forces are disengaged. Numerical results proved that there is no danger of the collision between the drum and the frame. The model also allowed estimation of the forces transmitted from the drum onto the frame through the suspension. The model was validated by the experiments carried out at a stand dedicated to measuring the vibration of the washing unit suspended on original and new dampers. The reduction of the frame vibration without perceptible increase in the drum vibration was observed.