Question

In a reverted gear train, the input pinion (15 teeth) drives a gear (60 teeth) compounded with a pinion (20 teeth), which in turn drives the output gear. If all the gears are of same module, the velocity ratio (input/output) is?

• A. 4
• B. 12
• C. 14
• D. 11

Answer 1

The correct option is D 11


$z_A=15$
$z_B=60$
$z_C=20$
$z_D=z_A+z_B-z_C$
$z_D=55$

$\frac{N_A}{N_D}=\frac{z_D\times z_B}{z_A\times z_C}=\frac{55\times 60}{15\times 20}$

$\frac{N_A}{N_D}=11$