what is crankshaft

A crankshaft is a mechanical component used in a piston engine to convert the reciprocating motion of the pistons into rotational motion. It is a rotating shaft containing one or more crankpins, which are driven by the pistons via the connecting rods. The crankpins are also called rod bearing journals, and they rotate within the "big end" of the connecting rods. The crankshaft is located within the engine block, held in place via main bearings which allow the crankshaft to rotate within the block. The up-down motion of each piston is transferred to the crankshaft via connecting rods. A flywheel is often attached to one end of the crankshaft to smoothen the power delivery and reduce vibration. Crankshafts are made from steel or cast iron, using either a forging, casting, or machining process. They are subjected to enormous stresses, in some cases more than 8.6 tonnes (19,000 pounds) per cylinder.