Abstract: A drive train is situated between an electric motor and a rotatable support disk to which an exchangeable cleaning or treatment implement or tool is fastened. In order to prevent overloading of the motor as well as to optimally adapt the speed of rotation of the support disc to operating conditions, especially the surface properties of the floor, the drive train possesses a friction transmission drive, in particular a friction wheel drive. This friction transmission drive automatically alters the rotational speed of the support disc in accordance with the torque required by it with a constant driving torque of the motor.