A chain drive unit (4, 5, 6) for reducing chain vibrations comprising a chain wheel unit (43) with at least two sprockets (431, 432) that are arranged parallel on a common rotation axle, at least two parallel chains (51, 52) engaging these sprockets (431, 432). At least one damping element (6) connecting two adjoining chains (51, 52). The circumferential orientation of two adjoining sprockets (431, 432) differs by a partial pitch (pP) and the damping element (6) comprises a first fixation (61) on its one free end for the lateral fixation to the first chain (51), a second fixation (62) on its opposite free end for the lateral fixation to the second chain (52) and a force transmission unit (63, 8, 9) arranged between the first and the second fixation transmitting an applied force from the first fixation (61) to the second fixation (62) and vice versa.