| Due to the clean and renewable nature of wind energy,wind power generation is becoming more and more widely used.Gearbox is an important mechanical component of wind turbines,however,the complex working environment leads to frequent failures and difficult maintenance,so the fault diagnosis of gear transmission system has important research significance.The research on gear failure mechanism is the premise and basis of fault diagnosis,and this paper takes the gear transmission system as the research object to solve the meshing stiffness of gear under crack fault,pitting corrosion fault and coupling fault,and analyze the dynamic response characteristics of the system under coupling fault.The main research contents of this paper are as follows:Firstly,the meshing stiffness change of the gear under crack and pitting single fault is analyzed.Aiming at the phenomenon that the gear base circle and the tooth root circle do not coincide,a corresponding variable-section cantilever beam model is proposed,and the meshing stiffness calculation formula under different conditions is derived.A crack failure model with linear expansion in the depth direction is constructed,the gear meshing stiffness under different crack fault degrees is solved,and the influence of crack depth and crack angle on stiffness and its components is comparatively analyzed.A cylindrical pitting corrosion distribution model is established,and different pitting corrosion degrees were realized by changing the pitting radius,depth and number,and the influence of pitting corrosion parameters on stiffness and its components is compared and analyzed.Then,based on the calculation principle of gear crack and pitting single fault meshing stiffness,a pitting corrosion-crack coupling fault model is established.On the basis of the improved potential energy method,according to the relationship between crack and pitting corrosion,the calculation formula of meshing stiffness in different states is derived.The meshing stiffness of the coupling model under different fault degrees is solved,and the evolution law of the meshing stiffness of the coupling model with pitting corrosion propagation is studied when the crack degree is fixed.The meshing stiffness is solved based on the finite element method,and the results obtained by the improved potential energy method and the finite element method are compared to verify the effectiveness of the coupling model.Finally,the dynamic response of the gear drive system with coupling fault is studied.The centralized parameter model of the six-degree-of-freedom gear transmission system is established,and the vibration displacement response of the system is obtained by solving the gear meshing parameters under different fault degrees.The fault signal characteristics are analyzed from the perspective of time domain and frequency domain,and the influence of fault degree on the signal frequency band is studied.Compare the simulation signal with the experimental signal,and analyze and verify the accuracy of the established coupling model.The changes of time-domain indexes of different fault signals are analyzed,and the sensitive indexes of coupling faults are compared. |
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