Crankshaft - An Overview

The Crankshaft is a rotating components which converts the reciprocating motion of the piston into rotary motion.  The power generated by the pistons is transmitted to the crankshaft.  The Crankshaft has a number of crankpin to which the pistons are connected.  The crankshaft has counterweights to provide static balancing. 

The Crankshaft rests on the engine block.  The crankshaft is supported by bearing journals.  The crankshaft is made of ductile iron.  It is designed to withstand heavy impact loads and high centrifugal forces.  The Crankshaft also has high fatigue strength to withstand cyclic loading.  Crankshafts can be made by either forging or casting.  Forged castings are stronger. They are used for heavy duty applications.  For small and moderate sized engines, cast crankshafts are used.

Crankshafts are made of steels containing manganese, chromium, molybdenum, etc.  They are hardened using techniques such as surface hardening and nitriding.