International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This study presents to determine the contact stress in rolling bearings by using analytical and numerical method. Analytical solution is obtained by using Hertizan contact theory. Obtained analytical solution by this theory require comparison with the numerical calculations to obtain more accurate results for contact problems. Because of that the same problems are also examined by using finite element method. The geometry of the model being studied gives different type of contact configurations such as a point or line of contact. In cylindrical roller bearing the contact form is line contact and for the ball bearing the contact characteristic is point contact. High stress occurs on both of these two contact areas. Contact stress causes elastic or plastic deformation and the contact area will change depending on the magnitude of the contact stress. Therefore, it is really important to calculate more accurate stress at the contact area.

In this study, optimisation of speed gears for a tractor transmission was performed with KISSsoft software. Optimisation was carried out under three constraints. These constraints are input power-torque, volume for system in transmission and gear ratio for each speed. The purpose of this study was to optimize the module, face width, gear quality, centre distance, number of teeth, helix angle, addendum modification coefficient and pressure angle for each speed considering the constraints. Tooth bending stress, tooth contact stress, contact ratio and specific sliding were considered for evaluation during optimisation. Strength calculation of gear pairs which were optimized and defined all geometrical parameters with KISSsoft were also calculated with mathematical model indicated in ISO 6336. Then, the results were compared.