Virbration And Noise Analysis Of Bridge Crane Reducer Under Typical Operating Conditions

Bridge crane is an very important tool in modern industrial production,it is a device to carry materials,reduce physical labor,improve work efficiency and achieve safe production,which widely used in the factory workshop,port and warehouse to lifting tasks.There is an alternating movement of lifting,moving and unloading in the working cycle of bridge crane.Therefore,the mechanical system will produce strong impact vibration during bridge crane operation.As the core part of the bridge crane,the reliability and operating comfort of bridge crane are directly affected by the vibration and noise performance.The reducer with high reliability,light weight and low vibration direction is urgently needed along with the development of equipment manufacturing technology.Therefore,it is of great significance to study dynamic characteristics of the reducer under typical working conditions,which can provide the guidance for the design and control of the vibration and noise.This paper takes the reducer of bridge crane as the research object,the dynamic load of crane reducer under typical working conditions are calculated;the internal dynamic excitations are obtained under the condition of load torque variation;Based on shafting element method and finite element method,the dynamic characteristics of reducer are studied,the test of vibration and noise are carried out.The main research works in this paper can be summarized as follows:(1)According to the actual parameters of crane,the dynamic model of crane hoisting system under three typical working conditions are established by using lumped mass method.The dynamic differential equations under the conditions of lifting,lowering and braking are respectively obtained.The load variation curves of the reducer under different conditions are obtained.(2)Considering the contact,bending,shear,axial compression and the elastic stiffness,the time-varying meshing stiffness of helical gear pairs are calculated by analytical method,and the results are compared with those obtained by static contact finite element analysis,the correctness of the analytical method is verified.The time-varying meshing stiffness of gear pairs at different levels are calculated by analytical method,and the dynamic excitations of the transmission system are simulated.(3)Based on the shafting element method,the dynamic model for transmission system of bridge crane reducer is established.The vibration characteristics of the transmission system under rated working condition are calculated and compared with the ANSYS analysis results and the vibration experimental results.The accuracy of the dynamic model built by the shafting element method is verified.The vibration characteristics of the transmission system under typical working conditions of lifting,lowering and braking are calculated respectively by using the shafting element method.(4)The acoustic boundary element model of the reducer box is established,the frequency domain value of vibration displacement of reducer’s surface node is used as boundary condition.The surface sound pressure and the sound pressure of the filed points under rated working conditions are calculated by using the direct boundary element method.The radiated noise of each field point is compared with the measured ones,and the results are in good agreement.