Taking gear as the research object, starting from different research methods, through the establishment of gear system dynamic model, the theoretical modeling and simulation research are carried out for the early micro pitting fault and the moderate degree pitting fault of gear respectively. By analyzing the dynamic response signal of the simulation model in time domain and frequency domain, the influence law of gear pitting fault on the dynamic response of gear system is explored. The experimental platform for early micro pitting fault of gear and the experimental platform for moderate pitting fault of gear are built respectively. The correctness of the theoretical model and simulation results of gear pitting fault is verified by analyzing the vibration acceleration signal measured by the experiment. At the same time, the dynamic strain of gear tooth root is measured by using FBG sensor, and the meshing stiffness and dynamic response of gear system are calculated based on semi analytical method. Based on this, a set of diagnosis method for gear pitting is proposed.
1: Firstly, the source of the subject is explained, and the research purpose and significance of the subject are discussed. The significance of gear system dynamics research and gear system experiment research is expounded. This paper summarizes the research status of the four related fields
1) Research on the simulation model of gear pitting fault;
2) The dynamic model of gear system is studied;
3) The research of gear stiffness excitation and friction excitation;
4) Experimental research on gear pitting failure.
2: Firstly, the meshing process of gear is briefly introduced, and then a nonlinear gear dynamic model with six degrees of freedom considering the influence of sliding friction is established by using the lumped parameter method. Then the method of calculating the time-varying meshing stiffness of healthy gear and pitting failure gear based on energy method is introduced. Finally, the gear friction model is briefly described.
3: Based on the established gear system dynamics model, the gear system dynamics simulation is carried out from three aspects, that is, only considering the stiffness excitation, only considering the friction excitation, and considering the stiffness excitation and friction excitation comprehensively. By analyzing the dynamic response signal of gear system dynamic model in time domain and frequency domain, the influence law of gear pitting fault degree on dynamic response of gear system is explored.
4: The dynamic response calculation method of gear pitting fault based on experimental data is mainly studied. The vibration response of the gear system and the dynamic strain of the gear root are measured by using the vibration acceleration sensor and the fiber Bragg grating sensor respectively. According to the potential energy principle and material mechanics theory, the relationship between the tooth root bending strain and the gear meshing stiffness is deduced, and the meshing stiffness of the healthy gear and the gear with moderate pitting corrosion is obtained by calculating the dynamic strain of the tooth root measured by the fiber Bragg grating sensor, and then the dynamic response of the gear system is analyzed by using the dynamic model of the gear system. The simulation results are verified by the vibration acceleration signals measured by experiments.
5: This paper mainly studies the early micro pitting failure of gears, and builds an experimental platform for early micro pitting failure of gears. Vibration acceleration sensor and fiber Bragg grating sensor are used to monitor the gear boxes with different gear states (healthy gears and 3 gears with different degrees of pitting failure). Firstly, the correctness of theoretical modeling and simulation results of gear early micro pitting fault in the analysis of vibration acceleration signal in time domain and frequency domain is verified, and then the performance of fiber Bragg grating sensor in the diagnosis of gear early micro pitting fault is evaluated by analyzing the fiber Bragg grating strain signal in time and frequency domain.