Rotor bearing for an electrical machine

A disk armature generator for generating electrical energy from rotational energy of a wind power turbine installation, wherein the disk armature generator comprises at least two stator components mutually offset axially along a generally horizontal rotation axis of the disk armature generator, and a disk armature with at least one ring- or disk-shaped rotor component which is mounted between the at least two stator components via at least one ball bearing comprising a radially inner connection element and a radially outer connection element, so as to be rotatable around the rotation axis of the disk armature generator, wherein a first one of the at least two stator components comprises a gearbox-side stator winding, wherein a second one of the at least two stator components comprises a tower-side stator winding, wherein the at least one ring- or disk-shaped rotor component comprises magnets between the gearbox-side stator winding and the tower-side stator winding, and wherein the rotor comprises an input-side connection for a planetary gearbox, wherein an output shaft of a sun gear of the planetary gearbox extends coaxially with the rotation axis of the disk armature and is coupled to the at least one ring- or disk-shaped rotor component of the disk armature, wherein the at least one ball bearing associated with the at least one ring- or disk-shaped rotor component of the disk armature is configured as a double-row angular contact ball bearing with two rows of balls having a contact angle of between 40° and 50° relative to the rotation axis of the disk armature generator, which double row angular contact ball bearing is supported by a housing of the generator, wherein the balls in both rows of balls roll along a respective raceway for each row, which raceways are formed on a common ring of the double-row angular contact ball bearing, which common ring of the double-row angular contact ball bearing with its both raceways is penetrated by the output shaft of the sun gear of the planetary gearbox, wherein the output shaft of the sun gear of the planetary gearbox is coupled to the at least one ring- or disk-shaped rotor component of the disk armature at a place beyond the ball bearing, and the output shaft of the sun gear of the planetary gearbox extends through the ball bearing, wherein the coupling between the output shaft of the sun gear of the planetary gearbox and the at least one ring- or disk-shaped rotor component of the at least one disk armature is implemented by means of at least one device for elastic force transmission arranged inside the generator rotatably about the rotation axis of the disk armature generator, wherein the device for elastic force transmission comprises at least two rotating elements, at least one of which comprises a shaft ring or a coupling disc.