Practical Formula for Contact Stress of Helical Gear Teeth.

In the present paper, a practical formula for the contact stress of helical gear teeth was investigated. The contact stresses of meshed helical gears with various helix angles, numbers of teeth and overlap ratios were calculated, and the meshing position (worst loading position) of maximum contact stress on the pitch point of helical gears was examined. On the basis of the calculated results, approximate equations for the load sharing factor and the maximum distributed load at the worst loading position were derived. By using these approximate equations, a new practical formula for the maximum contact stress of helical gear teeth was proposed. Furthermore, the results by this formula were compared with measured results and the results calculated by the various conventional formulas for surface durability of helical gears.