Abstract: A driving assembly for controllably driving a slide with respect to a bed includes a rack and at least a controllable-motor driven pinion engaged with the rack. The pinion forms a single body with the motor shaft, which is rigid with a supporting element defining a circumferential chamber for providing the supporting element body with a U-shape cross-section. The motor includes a rotor having a rotor shaft, the end portions of which are supported by bearings engaged in recesses defined in cover elements which are rigidly coupled to a body of a motor stator.