Research On Tooth Profile Modification Of Spur Gear Engagement Pair

Gear drive, as we know, the most popular used form in mechanical transmission, has an extremely vital part in machine tools.drive to a large extent influences the precision of the whole machine tool. Just for this reason, the performance of gear drive is of great significance to the excellent performance and reliability of the entire machine tool. However, variation of contact ratio, manufacturing and installation error, for example, always lead to vibration and the noise, seriously impacts gear performance of transmission. According to many studies the modification of gear tooth is an effective measure to solve this trouble. So, in this paper, so as to give a theoretical base for the modification of gear tooth and better the performance of gear transmission, the tooth profile modification ways of spur gear and also the dynamic response of modified gear system are analyzed.First and foremost, in this paper, literatures about gear tooth modification and gear system dynamics are summarized, fundamental theories of tooth profile modification and transmission error are provided, and the three elements of tooth profile modification are offered. It also proposed a method on the basis of the maximum amount of tooth interference under static load.Next, finite element method and analytical method are respectively used to tackle with the static transmission error. The results have shown that approximations and limitations appear using the analytical method, so it shows finite element method is the right choice for this study. Next giving the detail process of modeling parameterized finite element model of the gear pair, solving static transmission error of gear pair with different modification curves, and finally evaluating the modification effects on the basis of harmonic component amplitudes of static transmission error, thus in this way, the relatively good modification curve is gotten.What follows next is using the aforementioned relatively good modification curve, the effects of load, gear hole radius and extended tooth contact to the static transmission error of gear systems. According to further analysis of the static transmission error curve, a better modification curve is proposed. The superiority of improved modification curve is testified by comparing it with others, and then, by applying different gear parameters under work conditions, the universality is verified.Finally, a nonlinear dynamic model of modified gear system is established by taking time varying meshing stiffness and time varying nonlinear backlash caused by gear tooth modification into consideration. The validity of the modification method is verified from the perspective of dynamic response through comparing dynamic results with improved modification curve or not. Afterwards the effects of the maximum modification amount and load to the dynamic response of gear systems are discussed, conclusions are arrived that under certain load condition only targeted modification design would lead to the favorable modification effect, while one certain modification cannot be suitable for all load cases.