Dynamics Analysis And Profile Modification Of Helical Gears In Marine

With the developing of industrialization, Gearbox systems are widely used in engineering, because of accurate drive ratio, high cycle life and great transmission power. The entire process of gear transmission is very complicated, vibration and noise of gear is exacerbated by load fluctuation and gear backlash. Therefore, the requirements on transmission performance have been increasing recently, it is significant for improving the capacity of the gear, reducing vibration noise and fatigue damage to study the dynamic characteristics of the gear transmission system.This thesis focused on gear transmission system in marine. The influence of backlash on the system was considered, the time-varying torque and the contact stress in the process of gear meshing were studied under the tooth profile modification through the statics and dynamics analysis. The main contents in this thesis are following:1. Helical gear model was built by parameterized design. The finite element model of gear pair was established through ANSYS Workbench, the static contact deformation, contact stress and contact pressure at different meshing positions were carried out.2. The gear stiffness coefficient, damping coefficient and impact index and other parameters on contact surface were determined via multiple simulations. The coupled model of rigid and flexible of gear transmission system was built through ADAMS, the dynamic meshing force and time-varying load torque curve were extracted under considering the influence of backlash.3. Gearbox system models were established, and the natural frequencies of the system were gained using ANSYS Workbench. Using AWE transient dynamics module, the time-varying torque was as a dynamic stimulation. The time-varying contact stress curve and the contact pressure curve were obtained and the change of the load mutation was revealed.4. Two profile modifications such as long and short were proposed by determined the parameters of the tooth profile. Aiming at gear pair meshing transmission with and without modification, the statics and dynamics performance of contact were analyzed. It shows that profile modification could improve the equivalent stress distribution of tooth surface effectively, and decrease the magnitude changes of the load torque and contact stress.