The helix angle factor of helical gears.

This paper presents a study on the helix angle factor in considering the difference between root stresses of the helical gear and its virtual spur gear in the normal section. The calculation of bending strength of the helical gear is commonly based on the virtual spur gear. The root stresses of helical gears with various helix angles, numbers of teeth and overlap ratios were calculated, and the meshing position of maximum root stress (worst loading position) was examined. On the basis of these results, the helix angle factor of helical gears was clarified, in which the effect of load distribution on the line of contact is taken into account. Furthermore, the helix angle factors used in the various formulas for the bending strength of helical gear were compared with the results obtained in this paper.