W-N Type Gear Tooth Profile in View of the Radius Curvature

The feature of W-N (Wildhaber-Novikov) gear is that the engagement of tooth surfaces becomes a contact between concave and convex surfaces, resulting in small relative curvature and high surface durability. However, this gear has a defect that it is very sensitive to the center distance error. So, we developed the tooth profile that causes it to become insensitive to the center distance error without injuring the advantages of the W-N gears. We clarified that the relationship between the change in the center distance and the operating pressure angle differs depending upon the rate of change of radius curvature of the tooth profile, and studied and indicated the tooth profile having what radius curvature is suitable for the W-N type gears.