Research On Dynamic Modeling Of Gear Spalling And Fault Diagnosis Of Intelligent Bearing Signal

Gear transmission systems have been widely used in various fields due to advantages in structure,transmission stability and transmission efficiency.However,the gear transmission systems often work at high-speed and overload conditions or sever environment,thus the gears are injured easily.The results of the gear faults ranges from economic losses to accident casualties.At present,due to the diversity of gear faults and the complexity of gear transmission systems,the study of the fault dynamic mechanism is not enough and sufficient.In addition,the traditional gear fault diagnosis is often based on vibration signal analysis of the gear box,however,due to the complex internal excitating sources and vibration transmission paths,the fault feature is easily weakened,resulting a certain error in diagnosis result.The appearance of intelligent bearing improved the situation.Therefore,it is of great theoretical and practical significance for improving the safety and reliability of the mechanical equipment to study the gear fault dynamic characteristics and the fault diagnosis method combined with the intelligent bearing vibration signal.Taking spur gear as the research object,a spalled gear tooth model is established,and the influence of spall locations and sizes on the time varying meshing stiffness are analyzed.Also,a dynamic model of the 6 degree of freedom is established to discuss the dynamic response.Based on the intelligent bearing technology,the micro sensor is integrated to the traditional bearing.It verified the advantage of fault feature extraction compared with the vibration signal outside the gear box.According to the characteristics of the dynamic response the vibration signal of intelligent bearing,a fault diagnosis method based on AR model is adopted,and the diagnosis and identification of the spall fault of gear is carried out.Which of all proof method is effective.This article mainly carried out the following work:(1)Considering the root circle and base circle do not coincide,the spalled gear model is established,the calculation formula of mesh-stiffness is derived,the time-varying mesh stiffness of the gear is calculated,and the influence of the different peeling positions and sizes on the time-varying meshing stiffness is analyzed.(2)The dynamic model of 6 degree of freedom gear transmission system is established.The dynamic response of the normal gear and fault gear in different working conditions is obtained.The characteristics of the time and frequency domain of the vibration response are analyzed,and the law of the influence between the gear spall fault and the vibration response is obtained and analyzed.(3)Using the technology of intelligent bearing,the bearing structure is restructured to integrated with MEMS sensor.The simulation experiment of the gear fault is designed and the test rig is built.The measurement point of acceleration sensor is arranged reasonably,and the vibration signal in different working conditions is acquired and analyzed.(4)Combining the characteristics of the dynamic response of spalled gear system and the vibration signal of intelligent bearing,a gear fault diagnosis method intelligent bearing signal is proposed,and the validity of the method is verified though the vibration signal of intelligent bearing.