Study Of Dynamics And Unbalance Correction In Vertical Hard Bearing Balancing Machine

Due to the unreasonable design,the material defect,the manufacture error and so on,it is usual that there is unbalance with the disk rotor.When the rotor with excess unbalance operates,the vibration and the noise will be generated,which may accelerate the wear of the bearing,damage the machine and even lead to the accident.So it is important to balancing the rotor.The manual balancing method,which utilizes the balancing machine followed by the manual correction,is domestically widely applied.However the efficiency and the precision stability of this artificial dependent method are far from satisfactory.As an alternative,the automatic balancing machine proves an ideal solution.Domestic products,unfortunately,are immature in quality,while their well-performed foreign made counterparts are expensive and adaptable to only a few rotors,which greatly hinder its wide domestic application.This thesis made an effort to solve the problems mentioned above and developed a vertical hard bearing automatic balancing system,which is aimed at the balancing of the domestic disc rotor.The mass of the rotor is below 20kg and the inner diameter ranges from 12mm to 250mm.The main work includes:1.The overall framework of the system is analyzed.The system is divided into the mechanical subsystem as well as the measurement&control subsystem.2.Dynamics of the unbalance test unit is studied.The stiffness ratio of between the main spring and the sensor is summarized.The test data proves that the automatic balancing machine has high measurement precision and low minimum achievable residual unbalance(emar).3.The asymmetric unbalance distribution algorithm(AUDA)is deducted on the basis of the symmetric one.Experiment shows that the AUDA can work effectively to eliminate the unbalance.4.The circular milling method for the thin-walled disc rotor is discussed,and the corresponding mathematical expression is derived.On the basis of the derivation,the theoretical value as well as the actual value of this method,and the error between them,are calculated.According to the engineering tolerances,the appropriate number of arc segments is selected.Through experiment this method is also verified.5.The unbalance measuring method during the rotor speedup is investigated,and the required actual achievement condition is introduced.The study and the test data show that this method is able to measure the unbalance accurately and hosts a similar precision of the normal method.