Study on the Contact Characteristics of High-Contact-Ratio Spur Gear Pairs with Flank-Modification under Dynamic Loading

Although the high-contact-ratio spur gear pair has the advantages of no axial force and reduced noise and vibration, it is easily affected by deformation and shaft deviation, which causes tip corner contact on tooth surface. As a result, vibration and tooth surface damage occurs. In practice, tooth flank modification is often used. However, the flank modification is an artificially designed tooth profile error, so the contact characteristics of the modified tooth surface must be simulated in advance. However, the existing loaded tooth contact analysis method is mainly aimed at the problem of tooth contact under static load, which has not yet incorporated the effect of dynamic load.Therefore, the aim of the study, as planned for two years, is to develop a dynamically loaded tooth contact analysis model for spur gear pairs based on the complete gear-shaft-bearing system. The tooth contact characteristics of the high-contact-rate spur gear pair having flank modification under dynamic load can be thus explored and also compared by other commonly used methods.This project, the first-year project, will focus on the development of the basic model for dynamically loaded tooth contact analysis. Not only the dynamic behavior of the gear drive can be analyzed by applying the actually calculated instantaneous meshing stiffness of the modified tooth flanks, but also the contact characteristics of the engaged modified tooth surface. The teeth of the gears always in contact, the tip corner contact and the torsional deformation of the shaft are only considered in this project, and the effects of errors, shaft deflection shaft, bearing deformation and friction forces are excluded. The research method is divided into four sub-items. Through "design and gear mesh analysis of modified high-contact-ratio spur gear pairs", a "dynamically loaded tooth contact analysis model" is established to analyze the dynamic characteristics of the gear system and the variation in the contact stress distribution on the tooth surface under the different conditions for gear-bearing arrangement, tooth flank modification and contact ratio. The calculated results are also are compared and verified by the "gear dynamic system model analysis" and "Co-Simulation with MSC.Adams and MSC.Marc software", respectively.The results of this project can be applied to design and develop of aerospace high-speed gears, and can also further to develop the dynamically loaded tooth contact analysis model for helical gear transmission and planetary gear transmission, which is helpful to improve the design technology in the field of high-speed gears and electric vehicle transmission gears.