Failure modes of any gears gear life evaluationsSolutionFail

Failure modes of any gears gear life evaluations

Solution

Failure modes of gears

1. Shock and impact loading

2. Fatigue - fluctuating load bue to bending, eccentricity and vibration

3. Pitting - severe wearing of gear teeth

4. Abrasion - gradual wear

5. Corrosion

3, 4. 5 are caused mainly due to insufficient or improper lubrication and moisture in lubricant.

Gear life evaluation

AGMA Standard 2105-D04 has introduced useful information to consider the fatigue load capacity of steel gears in the case of a high number of cycles

Rating methods accepted by standards to evaluate the load capacity of external spur and helical involute gear teeth operating on parallel axes are based on the contact stress resistance and bending strength]. The formulas evaluate gear tooth capacity as influenced by the major factors which affect progressive pitting of the teeth and gear tooth fracture at the fillet radius. The pitting and fracture of gear teeth are considered to be a fatigue phenomenon depending on stress cycles. Certification of gear load capacity is based on the confrontations of stress calculated by gear-tooth rating formulae with the bending and contact permissible stresses for gear materials.

AGMA Standard 2105-D04 provides the rating formulas and permissible stresses applicable for calculating the pitting resistance and bending strength of external gear teeth operating on parallel axes.