Study of the effects of tooth geometry on characteristics of contact

Study of the effects of tooth geometry on characteristics of contact In the aeronautic field even the smallest aspect can results determining in term of performance and competitiveness. There is a continuous request for lighter product to minimize weights and costs. In this context vibrations have a very important role. They are source of noise and could bring at unexpected resonances, therefore represents a critical aspect to analyze paying extreme attention. Even if this kind of investigations would be referred to a system, it it not possible yet to neglect the sub-systems analysis. For this reason, this thesis is focused on static and dynamic aspects of gears, in particular way on spur gears. One of the main causes of vibrations in these elements is that gears are not infinitely rigid, but they have teeth whose deformations varies in time. The reason of this variation is that the number of theet varies during a mesh cycle. This variable stiffness is called Mesh Stiffness and it is the cause of Transmission Error, a discrepancy between the pinion motion and the wheel motion. The aim of this thesis is to understand how geometric characteristics of the gears could affect on the variation of transmission error and, then, on the mesh stiffness. To realize that, after a brief description of of the main kind of gears and of their relative dynamic, the following step will be a detailed description of the two main modeling software used. Then will be analyzed from a static approach a model a gears pair varying the profile modifications and the torque applied, calculating the mesh stiffness with two traditional method and one slightly different to check the precious two. Once again form the static approach, form tooth geometry it will pass on the gear geometry, calculating the mesh stiffness studying what happens analyzing rigid and flexible gears varying the rim thickness. In the end, it will be presented a modeling solution in Transmission 3D, an Ansol software, which allows a fats and reliable dynamic analysis. In particular, thanks to this solution the time analysis has been reduced by 80%.