Answer to Question #162405 in Mechanical Engineering for Johan Nieuwoudt

Question

A 12 - diametrical pitch spur gear having 21 teeth rotates at 2000 rpm and drives a pinion at 750 rpm.

Calculate:

a) The number of teeth on the pinion

b) The pitch diameter of the gear

c) The pitch diameter of the pinion

NB: Assume the pitch diameter is measured in inches

Answer 1

a) 12 = $\frac{15}{Dg}$

$Dg = 1.25$ unit

b) $D =\frac{Tc \times Pc}{\pi}$

= $\frac{21 \times 0.262}{\pi}$

= 1.752 unit

c) Tp = $\frac{2000\times 21}{750}$

=56 teeth