Effects of Wear, Backlash, and Bearing Clearance on Dynamic Characteristics of a Spur Gear System

A six-degree-of-freedom gear pair torsional vibration model considering time-varying stiffness, damping, dynamic backlash, bearing radial clearance and comprehensive wear of the tooth surface is established by using the lumped mass method in this paper. According to the comprehensive wear of tooth surface, the wear severity is divided into non-wear, slight wear and severe wear. The triangular function is used to simulate the wear failure of tooth surface. The effects of backlash, bearing clearance and comprehensive wear of tooth surface on the steady-state response of the gear system are analyzed respectively. The results show that the radial clearance of the bearing intensifies the vibration and causes the step phenomenon at high speed. The backlash increases the amplitude of vibration, the meshing force and the impact of back of teeth. Moreover, the side frequency bands generated by amplitude modulation appear on both sides of bearing vibration frequency, and the continuous spectrum line appears near the meshing frequency as well. The increase of wear leads to the increase of transmission error amplitude, tooth back impact and the disappearance of side frequency bands on both sides of bearing vibration frequency. The main frequencies in the spectrum are meshing frequency and its high-order harmonic frequency, and the modulated sideband appears near the meshing frequency and its high-order harmonic.