Wear of internal combustion engine crankshaft

Koljenasto vratilo je dio mehanizma kojim se pravoctno gibanje klipova pretvara u kružno gibanje. Koljenasto vratilo je izloženo naglim opterećenjima, zbog udaraca klipova, nedostatkom maziva ili nekontroliranošću nivoa razine ulja u motoru, dolazi i do oštećenja njegovih popratnih dijelova kao što su klip, klipnjača i leteći ležajevi. U teorijskom dijelu prikazan je način izrade koljenastog vratila, teoretski rad klasičnog četverotaktnog motora te sile koje opterećuju koljenasto vratilo u radu motora U eksperimentalnom dijelu analiziran je dosjedni ležaj koljenastog vratila, leteći ležaj te klip. Ispitana je tvrdoća, sastav materijala te je određena mikrostruktura na tri navedena uzorka.The crankshaft is a part of the mechanism by which the rotaring motion of the pistons turns into circular motion. The crankshaft is exposed to sudden loads due to piston stroke, lack of lubricant, or uncontrolled oil level in the engine, resulting in damage to its accompanying parts such as piston, connecting rod and flying bearings. The theoretical part is shows the way of making a crankshaft, the theoretical work of a classic four-stroke engine and the force that loads crankshaft in the engine operation. In the experimental part, the crankshaft bearing, flying bearing and the piston were analyzed. Hardness,chemical composition of material and microstructure were determined on three samples