Question

Gearing contact is which one of the following?

(a) Sliding contact

(b) Sliding contact, only rolling at pitch point

(c) Rolling contact

(d) Rolling and sliding at each point of contact

This question was addressed to me during an interview.

Origin of the question is Reverted Gear Train topic in portion Toothed Gearing & Gear Trains of Machine Kinematics

Answer 1

The correct choice is (b) Sliding contact, only rolling at pitch point

The best I can explain: When pair of teeth touch at the pitch point ,they have for the instant pure rolling action. At any other position they have the sliding action.