Patent ID: 7576464

Claim:
A device for driving a cylinder ( 1 ) of a printing machine, having an electric motor ( 3 ) with a rotor ( 14 ) arranged coaxially with respect to the cylinder ( 1 ) and is connected so as to rotate with the cylinder, and a stator ( 15 ) is held on a frame construction ( 2 ) in which the cylinder ( 1 ) is mounted such that it can be displaced axially, the rotor ( 14 ) and the stator ( 15 ) being dimensioned and coupled to the cylinder ( 1 ) and the frame construction ( 2 ), respectively, so that during any axial displacement of the cylinder ( 1 ) possible during the operation of the printing machine, the gap ( 16 ) formed between stator ( 15 ) and rotor ( 14 ) remains constant both with regard to gap width (s) and with regard to gap length, wherein a housing ( 9 ) of the electric motor ( 3 ) that accommodates the stator ( 15 ) is fixed to an outer ring ( 7 ) of an antifriction bearing ( 5 ) used to mount the cylinder ( 1 ) in the frame construction ( 2 ) wherein the rotor ( 14 ) is guided such that it can be displaced axially relative to the cylinder ( 1 ).