Study On Transient Vibration Suppression Method Of A Vertical Axis Washing Machine

Washing machine has become an indispensable household appliance,and the vertical axis washer occupies a larger market share in Asia.During the dehydration process of the vertical axis washer,strong transient vibration often ocurrs,which reduces the user’s experience.For solving this problem,two new damping structures,lateral damping structure and planar variable damping structure,are proposed.The vibration suppression effects of these two structures are analyzed and verified through experiments.Firstly,the dynamic model of the vertical axis washing machine is established.The main parts of vertical axis washing machine are classified into two types,the kinetic energy and potential energy of each type are derived and the generalized forces of the suspension system are presented.The dynamic model of the liquid balancer is established and a ball model for simulating its effect is presented.At last,the dynamic model of the vertical axis washing machine is established using Lagrange equation.Secondly,a new lateral damping structure is designed with its working principle described.The damping force of the lateral structure is analyzed and a generalized force model is established.The influence of the key parameters,such as lateral damping,tangential damping,axial damping and spring stiffness,on the transient amplitude is studied.Then,the influence of the new damping structure on the stability characteristics of the vertical axis washing machine is disscussed.The bifurcation theory is used and the property of the dynamic balancer under the effect of the lateral damping structure is studied.The stability parameter regions are obtained,whose correctness is verified through numerical simulations.The result shows that stability of the system can be enhanced by the new damping structure.A physical prototype of the vertical axis washing machine equipped with the lateral damping structure is made.Experiments are carried out,different imbalances including fixed eccentric masses and real clothes are considered,which verifies the improvement and enhancement of the new lateral damping structure on the transient vibration and stability of the system.Then,a new variable damping structure is designed with its working principle introduced.Simulations are carried out and the effect of the structure for suppressing transient vibrations of the washing machine is proved.The influence of the structure on stability characteristics of the suspension structure and the balancer is analyzed.It is shown that the stability of the washing machine is not affected by the structure.The effect of several important parameters on the vibration amplitude and phase angle of the washer is analyzed,and the relationship between phase variation and system stability is studied.A physical prototype of the washer with a new variable damping structure is made,the optimal departure speed of the structure is determined through experiments,and its ability to suppress transient vibrations under different imbalances is verified.Finally,the influence of the lateral damping structure on vibrations of the cabinet is stduied.The model of the cabinet is established using a finite element software and the natural frequencies and vibration modes are analyzed.The accuracy of the finite element model is verified through modal experiments.Then,the rigid-flexible coupling model of the whole washer is established,and the influence of the lateral damping structure on vibrations of the cabinet is analyzed,and the correctness of several conclusions is verified through experiment.