Abstract :
A new method for computer aided tooth contact analysis in mismatched spiral bevel gears is presented. As the introduced tooth surface modifications in spiral bevel gears are relatively small and the conjugation of the mating surfaces is relatively good, thus it is assumed that the theoretical point contact of mismatched spiral bevel gears under load spreads over a surface along the whole or part of the “potential” contact line made up of the points of the meshing teeth surfaces in which the geometrical separations of these surfaces along the tooth face width are minimal. The method is based on the minimization of the function that determines these separations, defined as the distances of the corresponding surface points that are the intersection-points of the straight line parallel to the common surface normal in the instantaneous theoretical contact point with the pinion and gear tooth surfaces. The points with these minimal separations make up the potential contact lines. The method includes the determination of path of contact and transmission errors, too. A computer program implements the method. By using this program the path of contact, the potential contact lines, the separations of the meshing tooth surfaces along these contact lines, the angular displacements of the gear member and the variation of the angular velocity ratio through a mesh cycle are calculated. The influence of machine tool setting and relative position errors of meshing pinion and gear on tooth contact is investigated and discussed.
