Analysis of dynamic characteristics of aviation gear transmission <?A3B2 pi6?>system under abnormal state of misalignment

To solve the fatigue fracture problem caused by misalignment of the gear transmission system of an aero-engine, the Hertz contact theory and transient dynamic analysis method were used to establish a transient dynamic analysis model of the spur gear pair, and the time-varying meshing stiffness and contact stress of the gear pair were analyzed. The results show that the time-varying meshing stiffness also presents a periodic change with the periodic change of the double-single meshing. The time-varying meshing stiffness decreases when two teeth are meshed and increases when one tooth is meshed. The maximum meshing stiffness increases as the parallel misalignment angle increases. The parallel angle of the gear axis affects the contact stress of the tooth surface and the response of axial vibration displacement. With the increase of the misalignment angle, the gear meshing trace gradually shifts downward, the contact stress of the tooth surface increases obviously, and the stress concentration occurs. When the misalignment angle increases from 0.25° to 1.00°, the average contact stress value of the tooth surface increases from 100 to 550 MPa. The amplitude of axial vibration displacement increases with the increase of misalignment angle, and the maximum total displacement reaches 3.161 mm. With the increase of misalignment angle, the load at the tooth root of the gear increases, and the increase of the load at the tooth root manifests as the increase of the amplitude of the rotation frequency in the spectrum diagram. The research method and analysis results can be reference for the simulation analysis of the assembly abnormal state of the aviation gear transmission system.