FRICTION WHEELS

The motion which is transmitted by gear is usally a kinematic motion which is equivalent to the friction wheels or disc motions.

in order to understand the motion which is transmitted by the two toothed wheels consider one small and big circular wheels mounted on shaft having sufficient rough surfaces and pressing against each other.

now consider that the big wheel is keyed to the rotating shaft and the small wheel to the shaft to be rotated.

a little consideration will show you that when the big wheel starts rotating then with the help of this small shaft will also start rotate.

now see the small wheel rotated by big wheel upto that limit when the tangential force exerted by the big wheel does not exceed the maximum frictional force between these two wheels.