Question

Which of the following is the correct mathematical formula for module?

(a) D/N

(b) D/2N

(c) 2D/N

(d) 4D/N

This question was addressed to me during a job interview.

I need to ask this question from Terminology of Gear Tooth topic in portion Measurement and Testing of Gears of Engineering Metrology

Answer 1

Right choice is (a) D/N

For explanation I would say: Module is defined as the length of the pitch circle diameter / tooth. Thus, if Pitch Circle Diameter of gear is D and number of teeth is N, then module (m) is equal to D/N. It is generally expressed in millimeter.