Based on the fixed-end beam calculation. Includes the majority of effects.
Safety factor of contact fatigue
where:
|
S fe |
contact fatigue limit (material property) |
|
|
F t |
tangential force acting at teeth |
|
|
b w |
operating tooth width |
|
|
d 1 |
pitch diameter of pinion |
Safety factor of bending fatigue
where:
|
S n |
bending fatigue limit (material property) |
|
|
P |
diametral pitch (module inverse value) | |
|
b wF1,2 = min (b 1,2 , b w + 2m) |
tooth width for bending |
Factor calculations
where:
| μ |
Poisson's ratio (material property) |
|
E |
modulus of elasticity (material property) |
|
m |
module |
|
l |
geometry factor |
|
|
|
|
C Li |
life factor |
|
C R |
reliability factor |
|
K v |
|
|
K o |
overload factor |
|
K m |
|
|
J |
|
|
C G |
gradient factor |
|
C G = 1 for P > 5 |
|
|
C G = 0.85 for P ≤ 5 |
|
|
C S |
|
|
k r |
reliability factor |
|
k t |
temperature factor |
|
k ms |
mean stress factor |
