The Crankshaft Is The Most Important Part Of An Engine

The crankshaft is the most important part of an engine. It takes the force from the connecting rod and converts it into torque which is output through the crankshaft and drives the other accessories on the engine to work. The crankshaft is subjected to the combined action of centrifugal force of rotating mass, gas inertia force of periodic change and reciprocating inertia force, which makes the crankshaft bear the action of bending and torsional load. Therefore, the crankshaft is required to have enough strength and stiffness, and the journal surface should be wear-resistant, uniform and balanced.
In order to reduce the mass of the crankshaft and the centrifugal force generated during movement, the crankshaft journal is often made hollow. Oil holes are cut on each journal surface to allow oil to be introduced or extracted to lubricate the journal surface. In order to reduce stress concentration, the connection of the spindle neck, the crank pin and the crank arm are connected by a transition arc.
The function of the crankshaft counterweight (also called counterweight) is to balance the rotating centrifugal force and its moments, and sometimes the reciprocating inertial force and its moments. When these forces and moments themselves reach balance, the balance weight can also be used to reduce the load of the main bearing. The number, size and placement of balance weight should be considered according to the number of engine cylinders, cylinder arrangement form and crankshaft shape. The balance weight is usually cast or forged in one piece with the crankshaft. The balance weight of high power diesel engines is manufactured separately from the crankshaft and then bolted together.