Modeling and dynamic analysis of spiral bevel gear coupled system of intermediate and tail gearboxes in a helicopter

The coupled dynamic model of the intermediate and tail gearboxes’ spiral bevel gear-oblique shaft-laminated membrane coupling was established by employing hybrid modeling method finite element lumped mass. Among them, equation shaft constructed Timoshenko beam; gears were derived theoretically lumped-mass method, where effects time-varying meshing stiffness, transmission error, external imbalance excitation like considered simultaneously; laminated simplified to a parameter model, in which stiffness obtained simulation experiment. On this basis, several important parameters, including unbalance value, rotor excitation, oblique shaft’s length error amplitude, on system’s characteristics discussed. results showed that influences amplitude vibration response prominent, should be taken into consideration model. Due bending-torsional effect, lateral caused gear eccentricity would enlarge torsional vibration; similarly, rotor’s also varies shaft. effect between pairs mainly hit vibration. Also, as increased, tended diminish while axis orbit became larger. research provides theoretical support for design helicopter system.