Question

A gear of 40 teeth drives a pinion by doubling the speed. If the module is 3mm, the centre distance is

• A. 180 mm
• B. 120 mm
• C. 90 mm
• D. 60 mm

Answer 1

The correct option is C 90 mm

$\frac{N_G}{N_P}=\frac{1}{2}\left(given\right)$

$\Rightarrow \frac{z_P}{z_G}=\frac{1}{2}$

$\Rightarrow z_P=\frac{z_G}{2}=\frac{40}{2}$

$\Rightarrow z_P=20$

Centre distance (CD) = $r_P+r_G$

$=\frac{m}{2}(z_P+z_G)$

$=\frac{m}{2}(20+40)$

$=CD=90mm$