A crankshaft assembly which is designed for a reciprocating-piston machine of an internal combustion engine includes a crankshaft, a torsional vibration damper for damping resonance torsional vibrations of the elastic torsion modes of the crankshaft, and an output. The torsional vibration damper has a primary mass inertia and a secondary mass inertia, the primary mass inertia being rigidly connected to a crankshaft and the secondary mass inertia being coupled as a seismic mass with a viscous liquid to the primary mass inertia. The torsional vibration damper is configured to assume the function of a flywheel for reducing rotational non-uniformity in addition to the function of reducing the resonance torsional vibrations of the crankshaft. The torsional vibration damper is attached to an output end of the crankshaft, and the torsional vibration damper forms a centrifugal mass which is divided into a primary mass inertia and a secondary mass inertia, wherein the three functions of a clutch functional section, a flywheel and a torsional vibration damper are integrated into the torsional vibration damper.