Calculating Worm Gear Strength With CSN 01 4686
Based on the fixed-end beam calculation. Includes the majority of effects.
Safety factor of contact fatigue
where:
σ Hlim | contact fatigue limit (material value) | |
F t | tangential force acting at teeth | |
b w | operating facewidth |
Safety factor of bending fatigue
where:
Increase of Temperature Check
Safety against overheating: Q od ≥ P z
where:
Deflection Check of Worm Shaft
Resultant deflection if the worm is symmetrically mounted and has the length l = 2.5 b 1 :
where:
|
| moment of inertia | |
Allowable deflection: | ||
y D ≈ 0.004m | shaft with hardened worm | |
y D ≈ 0.01m | shaft with heat-treated worm |
Factor calculations
Z N ... service life (for contact)
1 ≤ ZN ≤ 1.8
Y N ... service life (for bending)
1 ≤ ZN ≤ 1.85
N Hlim , N Flim ... base number of load cycles (material value)
N K1,2 ... required number of load cycles (speed)
N K2 = 60 L h n 2
Z L ... lubricant
Z v ... circumferential speed
Z E ... material mechanical properties
where:
Z H ... mating teeth shape
Z ε ... length of contact curves
Y ε ... profile mesh effect
Y β ... helix direction
where:
Y F ... tooth shape (table value)
K H ... additional loads (for contact)
K H = K A K Hv K Hβ K Hα
K F ... additional loads (for bending)
K F = K A K Fv K Fβ K Fα
K A ... outside dynamic forces
where:
