Extended calculation method for determining the pitting load carrying capacity of bevel and hypoid gears

The flank load carrying capacity of bevel and hypoid gears is mainly limited by the failure modes pitting, scuffing, tooth flank fracture and the phenomenon micropitting. By application of a standardized calculation method, e.g. according to the international standard ISO 10300:2014, a first estimation of the flank load carrying capacity can be made based on the macro geometry of the bevel or hypoid gear set. According to method B of ISO 10300:2014 the complexity of the real geometry of bevel and hypoid gears is reduced to a virtual cylindrical gear geometry. The load carrying capacity regarding scuffing, micropitting and tooth flank fracture can be determined by using the virtual cylindrical gear geometry along the path of contact. However, the determination of the pitting load carrying capacity is carried out on a single representative point on the path of contact of the virtual cylindrical gear. This paper shows an extended calculation method for the determination of the pitting load carrying capacity of bevel and hypoid gears along the path of contact of the virtual cylindrical gear geometry. Due to the calculation along the path of contact the extended method allows a more precise estimation of the pitting load carrying capacity than the current standard calculation method ISO 10300-2:2014 using the same input data. Within this paper all relevant factors of the extended calculation method are explained in detail. Furthermore, the verification of the extended calculation method with calculation results of an intense validated loaded tooth contact analysis, corresponding to method A of ISO 10300-2:2014, is presented.