Camshaft and Crankshaft, the Difference Between The Two
A camshaft has a cam follower that rides on the cam. The cam on the camshaft can have more than one high spot on it, so it is possible for the cam follower to move forward and backward a couple of times for each rotation of the camshaft. Usually the power flows in only one way. The cam can have a complex shape, so the cam follower can move in motion patterns that are wave like. The cam follower usually cannot drive the cam, so the camshaft drives the cam follower.
A crankshaft has either one or more offset sections where a connecting rod is attached to it. The crank will always move in a circle, moving the connecting rod in a smooth wave like motion. The connecting rod can only move once back and for every rotation of the crankshaft. The power can flow in either direction. In crankshaft, it can drive the connecting rod, or vice versa.
If minimal power motion needs to be transmitted, particularly if it is a non sinusoidal motion, then a camshaft is used. If a significant amount of power needs to be transmitted, a crankshaft is usually used.