Threshing and cleaning device of corn harvester

The utility model discloses a threshing and cleaning device of a corn harvester. The device comprises a vibrating screen arranged below a roller and concave plate combination of the harvester, three main fans are arranged on the side, located at the inlet end of the roller, of the vibrating screen, the three main fans are evenly arranged in the width direction of the vibrating screen, the three main fans are frequency conversion fans, each main fan is provided with a main air outlet and an auxiliary air outlet, the main air outlets are located on the upper side of the vibrating screen, and the auxiliary air outlets are located on the lower side of the vibrating screen. A suction fan is arranged on the side, located at the outlet end of the roller, of the vibrating screen; an impurity rate sensor is arranged below the vibrating screen, and the main fan, the impurity rate sensor and the suction fan are all electrically connected with the VCU controller; the cross section of the vibrating screen is in an arc sha