What is vibration damper

VIBRATIONS DAMPER

The power impulses tend to set up a twisting vibration in the crankshaft. When a piston moves down on its power stroke, it thrusts, through the connecting rod, against a crankpin with a force that may exceed 2 tons. This force tends to twist the crankpin ahead of the rest of  crankshaft. Then as the force against the crankpin recedes, it tends to untwist, or move back into its original relationship  with the rest of the crankshaft. This twist-untwist action, repeated with every power impulse, tends to set up an oscillating motion in the crankshaft. This is called torsional vibration. If it were not controlled, it could cause the crankshaft to break at certain speeds. To control torsional vibration, devices which are called vibration dampers, or harmonic balancers, are used. These dampers are usually mounted on the front end of the crankshaft and the  drive-belt pulleys are incorporated into them.

    A typical damper is made in two parts, a small inertia ring or damper flywheel and the pulley. They are bounded to each other by a rubber insert about 1/4 inch ( 6mm ) thick. The damper is mounted to the front end of the crankshaft. As the crankshaft speeds up or slows up or down, the damper flywheel has a dragging effect. This effect, which slightly flexes the rubber insert, tends to hold the pulley and crankshaft to a constant speed. This tends to check the twist, untwist action, or torsional vibration, of the crankshaft.