A CROP PROCESSING ASSEMBLY FOR A COMBINE HARVESTER

A crop processing assembly comprises a tube-shaped cage structure and a threshing and separation rotor (7) mounted in said cage structure. The cage structure comprises one or more curved gratings (10) at the bottom and a cover (16) at the top, so that the rotation of the rotor actuates the movement of crops along a helicoidal path through the gap between the rotor and the cover and gratings. Inclined guide vanes (30) are preferably arranged on the inner surface of the cover to provide guidance to the crops. The cover comprises a step (17) between an upstream portion (16a) of the cover and a downstream portion (16b) of the cover, so that the gap between the rotor and the cover is larger in the downstream portion than in the upstream portion. The step is oriented at an oblique inclination angle (α), when the cover is regarded in a parallel projection view from a position above the step. The inclination angle is configured so that the step (17) has the function of guiding the crops along the helicoidal path. When guide vanes are present, the step itself performs the same function as the vanes, so that the mounting of one or more additional vanes in the stepped transition area is not required.