To Örebro University

In gear design, it is essential to use accurate geometry and generate calculations and all dimensions correctly. In helical gears, the geometrical calculation of the tooth root has not been sufficiently presented to facilitate gear tooth root modelling by equations. In the present article, an analytical method is presented to calculate the root geometry of helical gears and also the necessary design parameters are introduced. Method 1, which was presented in an earlier article for calculating the root fillet, is used and tested in the present article and it is shown that incorrect results are generated for helical gears, but however for spur gears, this method works accurately. In the present article, a new alternative method, namely Method 2, is developed and presented for the root fillet geometric calculation for helical gears. The geometry from both Windows LDP software and the developed method are compared. A perfect agreement is shown in the results, and thus, the equations presented in this article can be applied to helical gear geometry.