For the gearbox shown, we know the number of teeth for the following gears: Z1 = 20, Z2 = 34, and Z3 = 18. Shafts 0, B, and Z are coaxial.
The gear sets have modules m12 = 4 mm and m34 = 3 mm.
a) Determine the number of teeth for gear 4 (Z4).
b) Determine the ratio ωZ/ωB, i.e., from shaft Z to shaft B, when ω0=0.
c) Determine the ratio ωZ/ω0, i.e., from shaft Z to shaft 0, when ωB=ω0/2.
N.B. – All gears are cut with a standard rack (α = 200 , ha = m , c = 0.25m), with no displacement.
W1 = 3kN = 3 × 103 N
W2 = 2kN = 2 × 103 N
W3 = 1kN = 1 × 103 N
Number of revolutions
n1 = 0.1n
n2 = 0.2n
n3 = 0.3n
n4 = [1- (0.1+0.2+0.3)]n = 0.4n
Life of the bearing corresponding to reliability of 95% L90 = 20 × 106 rev
Life of the bearing corresponding to reliability of 90% L90 = ?
b = 1.17
Equivalent dynamic loads
So, the dynamic load rating,