Analytical Study of Engine Central Drive Bevel Gear Fracture

This study investigates the repeated fracture of intermediate driven bevel gear webs in engine central transmission systems. Morphological, fracture surface, and finite element analyses were conducted on four consecutive failure cases to identify the underlying mechanisms. Results indicate that the failures are characteristic of high-cycle fatigue (HCF) driven by nodal diameter-type vibrational stress. In three cases, surface pits induced by laser marking served as critical stress concentrators, initiating cracks away from maximum nominal stress locations. To mitigate these failures, vibration-damping rings were integrated into the web, and laser marking depth was strictly controlled. These optimizations effectively prevented subsequent gear fractures. This work provides a practical reference for the structural design and manufacturing reliability of similar high-load transmission components.