The calculation formula for gear bending strength can be selected and adjusted according to different situations and requirements. The following are several commonly used calculation formulas:

Calculate based on the bending fatigue strength limit of the tooth root:

σ F=(KFt/bm) · Yf · Ys

Among them, σ F is the bending fatigue strength limit of the tooth root, KFt is the load factor or safety factor, bm is the modulus, Yf is the stress adjustment coefficient, and Ys is the correction coefficient. This formula is mainly used for checking and designing the bending fatigue strength of the tooth root.

Calculate based on the fatigue strength limit of tooth contact:

σ H=(KHt/bm) · Yh · Ys

Among them, σ H is the fatigue strength limit of tooth contact, KHt is the load factor or safety factor, bm is the modulus, Yh is the stress adjustment coefficient, and Ys is the correction coefficient. This formula is mainly used for checking and designing the contact fatigue strength of tooth surfaces.

Calculate based on overall bending strength:

σ = （ σ F+ σ H) /2

Among them, σ F is the bending fatigue strength of the tooth root, σ H is the contact fatigue strength of the tooth surface. This formula is mainly used for checking and designing the overall bending strength.