Mechanistic insights into contact fatigue of helical gears under cyclic loading: Impact of center distance error in eccentric load and uniform load scenarios

The fatigue life of helical gear transmission systems is highly sensitive to critical geometric parameters, particularly center distance error (CDE). This study employs a combined approach of theoretical analysis and numerical simulation to systematically investigate the impact of CDE on the fatigue life of helical gears under cyclic operating conditions, along with its causal mechanisms. A rigid-flexible coupling finite element model based on eccentric load (EL) and uniform load (UL) configuration was established to analyze the influence mechanism of CDE on fatigue life. The results show that the life of the gear decreases with the increase of the center distance. The mechanism analysis determines the dynamic impact, bearing capacity, and oil film thickness (OFT) that the CDE affects the fatigue life, and then affects the contact stress. These findings provide important insights for the reliability-driven design and precision installation control of helical gear systems, and are of great significance for optimizing the performance of helical gear transmission systems in applications.