Feature: flange crack usually occurs at the root between two adjacent teeth. Some of the web cracks are caused by the radial propagation of the flange cracks, some of them are generated in the web itself, not necessarily to the flange.
Cause: flange fracture is usually the result of fatigue crack development of gear root fillet. If the residual stress of some part of gear is too high, it will form and promote the fatigue crack growth. For the insert type gear, the excessive interference between the flange and the wheel center can also cause the flange fracture. The damage of the spoke is mainly caused by the insufficient strength, stress concentration or vibration of the spoke.
Preventive measures: the size of rim and spoke plate shall meet the strength requirements. Local stress concentration factors, such as cutting marks, grinding and quenching cracks, sharp fillets at the transition between rim and spoke plate, should be reduced or eliminated. In the structural design, vibration reduction and anti vibration measures should be taken. For the inserted gear, the interference should be controlled properly.