An auto-balancer device for high spin-drying frequencies (LoWash Project)

VIBRATEC, 28 chemin du Petit Bois, 69131 Ecully Cedex, France

^a Corresponding author: christian.clerc@vibratec.fr

Abstract

Auto-balancing or active control balancing can be efficient solutions for high speed rotors with changing out-of-balance loads like washing machines in spin-drying mode. In the LoWash EU project, Vibratec is in charge to design, to build and to validate a balancing system for reducing the vibrations at high spin-drying speeds. The system is based on two trolleys rolling in a ring linked to the drum. The trolley shape allows a ring cross section optimization and they are equipped with a mechanism for escaping the disadvantage encountered at low speeds by similar devices. Analytical and multi-body models are first made for understanding the mechanisms, highlighting the driving parameters and drawing the final design of a first prototype which is inserted in a washing machine drum. Different tests are carried out for different initial unbalances and different rotation speeds: the residual unbalance is measured by means of a set of accelerometers mounted on the tub, while the mobile masses behaviour is observed by means of a large aperture swift camera. The test results highlight the auto-balancer high efficiency but also the sensitivity to geometrical defects which should be corrected in the next systems. According the theory, the balancing is efficient when the rotation frequency is significantly greater than the hanging frequencies. The multi-body model relevance is also demonstrated. A washer-dryer prototype including an auto-balancer second prototype and two other innovations, regarding thermal exchange efficiency and drum insulation, will be tested in operating conditions.