An Improved Load Distribution Model for Gear Transmission in Thermal Elastohydrodynamic Lubrication

Abstract

The gear drive generally operates in elastohydrodynamic lubrication (EHL) contacts, and the existence of oil film effectively reduces wear and improves transmission stability. However, little research has been devoted to studying the effect of lubrication characteristics on load distribution of gear transmissions. In order to investigate the coupling effect between the lubrication behavior and load distribution, an analytical load distribution model suitable for EHL contact spur gear pairs is proposed. The non-Newtonian transient thermal EHL solution, flexibility of meshing teeth, structural coupling deformation of the gear body and extended tooth contact are considered in the deformation compatibility condition for iteratively solving the load distribution. A parametric analysis is performed to determine the influence of load torque and rotation speed on load sharing ratio and loaded static transmission error. The transient lubrication behaviors based on the proposed load distribution model is compared with that obtained from the traditional model. A series of comparisons with different models demonstrated the correctness, significance and generality of the present model. The results show that it is necessary to consider the thermal EHL calculation into the iterative solution procedure of load distribution model for EHL contact gear pairs. The proposed model is a useful supplement for an accurate study of thermal EHL characteristics of gear transmissions.