The problem approached by the present paper is the determination of the gear tooth stiffness in helical gears using gear technique in a particular case of an overlap contact ratio equal to a natural number ([[epsilon].sub.[beta]] =1). The justifications of this task are: a) the decisive effect of the variation in time of the gear tooth stiffness on gear vibration and noise behavior; b) the possibility to use modern techniques of FEA in the complicated analysis of displacement specific for helical gears.
A short description of the state of the art in this problem is carried out below. Pioneering studies pertaining to the decisive effect of the variation in time of the gear tooth stiffness on gear vibration and noise behavior carried out, for example, Rettig (1957); Schlaf (1962), Bosch (1965). Previous research regarding the effect of contact ratio on the dynamic behavior of cylindrical gears achieved Rettig (1956), Baethge (1969), Ziegler (1971), Geiser (2002). The team of authors developed a careful and profound use of FEA techniques in the mentioned subject, some of their papers being Dobre, Mirica, Sorohan. (2006) and Dobre, Mirica, Gabroveanu (2008).
The present paper explores aspects of FEA studies (model, analysis, post-processing) of the static torsion gear tooth stiffness along the line of action for the geometrical case of [[epsilon].sub.[beta]] =1, for a model with a lower density on wheel length: 8 elements. This results in a new diagram of variation respecting the accuracy requirements related to the interference and a comparison with previous results (model with 25 elements/wheel length) given by Dobre, Mirica, Sorohan. (2006) and Dobre, …