Βέλτιστος σχεδιασμός ποδός σε ευθείς οδόντες εξειλιγμένης για μέγιστη αντοχή σε κάμψη με χρήση καμπυλών Bezier

Abstract

In this thesis, a method of using a novel fillet design for spur gear teeth, in order to improve their strength and their loading capacity, is developed and presented. According to this method, the conventional trochoidal fillet profile and the segment of the root circle that corresponds to the half of the space between two successive teeth is replaced by a suitable Bézier curve. The shape of this curve is altered by changing two parameters in order to create a tooth profile with reduced first tensile principal stress at its root fillet. These teeth are first modelled geometrically and then their behaviour in bending is studied by assuming loading at their Highest Point of Single Tooth Contact (HPSTC). The maximum principal stress that appears at the root fillet of each model is calculated using Finite Element Analysis (FEA). After the analysis of all the models, an interpolation method is used, in order to define the combination of the parameters that corresponds to the optimum model. The next step is to investigate if interference between the tip of the mating gear and the resulting tooth geometry, exists. Finally, the results of this thesis are compared with similar efforts that have been made in the past on improving the strength of spur gears.