Research On Rotor Unbalance Fault Mechanism And Its Precise Dynamic Balance Method

With the progress and development of modern industry,rotating machinery has become the most widely used type of equipment in the industrial sector.The most common type of failure in rotating machinery is unbalance.Therefore,the mechanism of rotor unbalance failure and dynamic balancing technology Development is very important.In practical rotor engineering applications,due to factors such as the structure of the rotor system itself,the rotor must be anisotropic.The anisotropy of the rotor will make the response of the same section of the rotor different in different directions.The axis trajectory of the rotor frequency is elliptical.If the vibration state of the rotor is still described in a certain direction of vibration,and according to the vibration in this direction,To perform dynamic balancing,errors will inevitably be introduced.However,the homologous information fusion technology of full vector spectrum can more fully describe the vibration state of the rotor,which makes up for the shortcomings of the traditional method.The full vector dynamic balance technology combining the full vector spectrum technology and the influence coefficient method can be well solved.Anisotropic rotor dynamic balance problem.According to the study of the unbalanced response of anisotropic rotor,the analytical solutions of unbalanced response under the Jeffcott rotor model,the anisotropic rotor model and the finite element model are derived.The anisotropy is numerically simulated to further study the characteristics of the unbalanced response of the anisotropic rotor.By combining the responses obtained from the three models and the results of numerical simulation,it can be concluded that the rotor axis trajectory is elliptical,the amplitudes in the x and y directions are different,and the phase difference is not 90 °.Under the influence of anisotropy during the entire speed increase,the response amplitude of the x and y directions will reach the maximum at different speeds,that is,the critical speeds in the two directions are different,so it is difficult to control the rotor system from only one direction.Perform a complete state description.Using the full vector spectrum can well integrate the differences caused by anisotropy,and have a more complete description of the power frequency response,which is helpful to judge the imbalance fault.The response of the rotor in different directions is affected not only by the anisotropy,but also by the excitation in the rotor system.Generally speaking,when performing dynamic balancing,it is generally believed that the frequency response is caused by unbalanced excitation.However,due to the environment in which the rotating machinery is located,there is also an environmental excitation at the same frequency as the frequency conversion.The dynamic characteristics of the system will change.At this time,there will be errors in the full vector dynamic balance method using the main vibration vector as the dynamic balance reference.Therefore,the balance target of the full vector dynamic balance method needs to be optimized.This paper proposes two optimization methods: 1 After the most physical parameters of the rotor are known,the angle of the environmental excitation can be obtained through numerical calculation.The dynamic balance can be performed by taking the vertical direction of the angle of the environmental excitation as a reference.2.Based on the full vector spectrum technology,the frequency conversion ellipse is equivalent to a frequency conversion circle,and the radius of the equivalent frequency conversion circle is used to replace the balance target in the full vector dynamic balance method,and the equivalent vibration vector unbalance response(EVUR)is defined.),Using the equivalent transduction circle radius as the magnitude of the unbalanced response,and the ellipse phase angle as its phase,this method averages the impact of environmental excitation in a certain direction,which can greatly reduce the environment The impact of incentives.Numerical simulations and model simulations have proved the advantages of the equivalent vector unbalanced response(EVUR)over the full vector unbalanced response(FVUR)under dynamic environmental excitation effects on the rotor.Because environmental incentives are like many non-linear factors,it is too expensive to perform simulations in experiments.Simulations are generally performed in simulations.Therefore,in the end,the dynamic balance table experiments of the anisotropic rotor under the influence of environmental excitations were performed using finite element software to verify the effectiveness of the equilibrium target of the equivalent vibration vector in the balance process and the advantages over the full vector dynamic balance method.