Question

An imaginary circle which by pure rolling action, gives the same motion as the actual gear, is called

(a) addendum circle

(b) dedendum circle

(c) pitch circle

(d) clearance circle

I got this question during an interview.

This question is from Law of Gearing-1 topic in section Toothed Gearing & Gear Trains of Machine Kinematics

Answer 1

Correct choice is (c) pitch circle

Explanation: Addendum circle is the circle drawn through the top of the teeth and is concentric with the pitch circle.

Dedendum circle is the circle drawn through the bottom of the teeth. It is also called root circle.

Pitch circle  is an imaginary circle which by pure rolling action, would give the same motion as the actual gear.