METHOD OF RESONANCE PREVENTION IN DRUM TYPE WASHING MACHINE Russian patent published in 2009 - IPC D06F37/20 

FIELD: individual supplies.

SUBSTANCE: invention relates to method of resonance prevention in drum type washing machine. The method comprises regulation of self-resonant frequency of the system. The centrifugal spinning of laundry is carried out within three stages τ₁, τ₂, and τ_3. Each stage is characterised by the value of drum rotation speed Ω₁, Ω₂, and Ω₃, rigidity of elastic support of a washing unit of the machine C₁, C₂ and C₃ and self-resonant frequency of the washing unit ω₁, ω₂, and ω₃. The drum is accelerated during centrifugal spinning of laundry within the first stage of time τ₁ till the value of angular frequency of rotation Ω₁ which is lower than oscillation frequency of the washing unit ω₁ characterised by subresonance oscillating mode of the washing unit is achieved. When angular frequency of drum rotation is achieved the value Ω₁<ω_1, rigidity of the elastic supports is abruptly reduced till the value C₂<C₁ so that oscillation of the washing unit is characterised by subresonance mode. The drum is accelerated till value is Ω₂>Ω_1, which defines set spin of laundry and set oscillation mode of the washing drum. Thereafter, the drum is decelerated with reducing angular frequency of its rotation Ω₂ till the value Ω_3, which is higher than self-resonant frequency of the washing unit ω₂ and corresponds to subresonance oscillation mode of the system. When angular frequency of drum rotation achieves the value Ω₃>ω₂ rigidity of the elastic supports is increased abruptly till the value C₃=C₁>C₂ so that oscillation of the washing unit is characterised by subresonance mode after which the drum is kept on decelerating till full stop.

EFFECT: vibration reduction with centrifugal spin during acceleration and deceleration of the drum.

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