Question

The contact ratio is the ratio of

(a) length of pair of contact to the circular pitch

(b) length of arc of contact to the circular pitch

(c) length of arc of approach to the circular pitch

(d) length of arc of recess to the circular pitch

I have been asked this question in an interview.

I would like to ask this question from Systems of Gear Teeth in chapter Toothed Gearing & Gear Trains of Machine Kinematics

Answer 1

Correct answer is (b) length of arc of contact to the circular pitch

The explanation: The ratio of the length of arc of contact to the circular pitch is known as contact ratio i.e. number of pairs of teeth in contact.