Bevel Gear Strength Calculation According to Merrit
Based on the fixed end beam calculation. Anticipates that the total circumferential force can only be carried by one tooth. Adds an extra contact check.
Allowable load
F all = π c min b w ζ m en μ≥ F t
where:
| | c min = min (c b , c c ) | minimum tooth allowable stress |
| | b w | operating facewidth |
| | m en | normal module at end (normal diametral pitch at end inverse value) |
| | μ | factor of dependence on the precision degree (material property) |
| | F t | circumferential force acting on the teeth |
| | 
| width factor |
| | where: | |
| | | K = 1.4 for straight teeth, 1.25 for helical teeth |
Safety factor
S = F all / F t
Bending factor
where:
| | σ Ab | allowable stress in bending (material property) |
| | r b | speed bending factor (table value) |
| | y b | shape bending factor (table value) |
Contact factor
where:
| | σ Ac | allowable stress in contact (material property) |
| | r c | speed pressure factor (material property) |
| | y c | shape pressure factor (material property) |
| | 
| size factor |
