Abstract: In order to research the dynamical responses of high-speed class helical gear transmission system with the wind turbine, the nonlinear dynamical model coupled with lateral, torsional and shaft for helical gear-rotor-bearing transmission system is established including the time-varying input/output torque, gear eccentricity, synthetic mesh errors, gravity and the nonlinearity of bearing. The dynamics differential equation is deuced by using Lagrange’s equation. On that basis, the dynamical characteristics with the effects of rotational speed, gear eccentricity, bearing clearance are analyzed. The simulation results reveal that the torsional vibration displacement is larger than those in lateral and shaft directions due to the influence of lateral-torsional-shaft coupled vibration, and the torsional vibration is the main vibration. With the increase of rotational speed, the vibration displacement increases obviously, the amplitudes of frequency exhibit significant fluctuation and the continuous spectrum components appear near the rotational frequency. The vibration responses of the system are significantly intensified with the increase gear eccentricity, which has deeper influence upon the vibration response in torsional direction than those other directions. The bearing clearance has not obviously effect on vibration response of the system, but the bearing has its own resonance frequency, and the effect of the variable stiffness frequency of the bearings on the system should be avoided during the system design. The research results lay a foundation for dynamical characteristics and fault diagnosis of the helical gear-rotor-bearing system of the wind turbine.

Key words: bearing clearance, coupled lateral-torsional-axial gear eccentricity, dynamic vibration, helical gear