Schaeffler North America

Internal Crankshaft Damper (ICD)

Internal Crankshaft Damper (ICD)

Crankshaft damper

The natural frequency of the crankshaft is excited when running a combustion engine, due to the gas and inertial forces. This causes the two ends of the crankshaft to twist strongly against one another, which can cause noise and torsional fractures of the crankshaft. To reduce the load on the crankshaft, torsional vibration dampers are generally used today, integrated with the belt pulley of the accessory drive at the free end of the crankshaft. In the absence of the space required for such a torsion vibration damper either inside or outside the crank housing, the LuK internal crankshaft damper provides a suitable solutions.

The ICD is seamlessly integrated into the crank arm and, like any damper with spring clutch, consists in principle of a rotating mass with defined mass reactance, which connects to the crankshaft via spring elements. The torsion resistance of the spring element and the mass reactance of the rotating mass produces the intrinsic frequency of the damper, which is matched to the intrinsic frequency of the crankshaft.

The housing of the internal crankshaft damper connects straight to the crankshaft, a speed-dependent damping occurs between housing and rotating mass. Friction damping occurs primarily in the friction bearings, which both absorb the rotating masses and at the same time act as guides. The spring elements are in steel pressure springs routed into cups. Steel pressure springs have the benefit over rubber spring elements of a more constant spring rate over temperature and, due to their higher energy absorption capacity, permit a higher vibration angle. The dampers now in standard production enable both packaging space and weight of the engine to be reduced.