Question

A commercial enclosed gear drive consists of a 20° spur pinion having 16 teeth driving a 48-tooth gear. The pinion speed is 300 rev/min, the face width 2.25 in, and the diametral pitch 6 teeth/in. The gears are grade 1 steel, through-hardened at 200 Brinell, made to No. 6 quality standards, uncrowned, and are to be accurately and rigidly mounted. Assume a pinion life of 10^8 cycles and a reliability of 0.90. Determine the AGMA bending stresses of the gear and the corresponding factors of safety if 5 hp is to be transmitted. Assume Ko = KB = KT = Cf = 1

Answer 1

S_h(new) = 1.29

yes new design S_h>S_h(old)

Step-by-step explanation:

solution:

Change Np into change Dp, V,
`W^(t)`, Y,
`K_(v)`,
`K_(s)`, I

Dp = Dp(old) = 2.667 ==> Dp(new) = 3.667

V = V(old) = 209.4 ==> V(new) = 288

`W^(t)` =
`W^(t)`(old) = 787.8 ==>
`W^(t)`(new) = 573

Y = Y(old) = 0.296 ==> Y(new) = 0.331

`K_(v)` =
`K_(v)`(old) = 1.20 ==>
`K_(v)`(new) = 1.23

`K_(s)` =
`K_(s)`(old) = 1.088 ==>
`K_(s)`(new) = 1.091

I = I(old) = 0.121 ==> I(new) = 0.110

S_h(new) = S_h(old)*(
`K_(v)`(old)/
`K_(v)`(new))*(
`W^(t)`(old)/
`W^(t)`(new))*(
`K_(s)`(old)/
`K_(s)`(new))*(I(new)/I(old))

S_h(new) = 1.29

yes new design S_h>S_h(old)