Practical Formula for True Root Stress of Internal Spur Gear Tooth

Abstract

The true root stresses of internal spur gears with various numbers of teeth and addendum modification coefficients were calculated by 2-dimensional elasticity theory and mapping function, and the position of critical section on tensile side of internal spur gear tooth was indicated. The stress concentration factors at the position of critical section were calculated under different loading conditions. A practical formula for true root stress of internal spur gear tooth was derived on the basis of these calculated results. Furthermore the root stresses calculated by this practical formula were compared with those by FEM and measured ones, and the validity of the practical formula was confirmed.