Wind screen mechanism based on grain screening integrated machine

The invention discloses a wind screen mechanism based on a grain screening integrated machine. A supporting ring is fixed to the inner surface of the circumferential side of an outer ring, and the supporting ring and a supporting column are connected through connecting strips. A worm gear is movably arranged on the surface of the supporting ring and engaged with a worm, and a rotation through holeis formed in the surface of the worm gear. A supporting plate is fixed to the bottom face of a bevel gear ring, and an air blower is fixed to the surface of the supporting plate. An inner threaded hole is formed in the surface of the supporting plate and internally movably provided with a threaded shaft. A large-hole screen is arranged in a discharging port for separating large particles and straw; an air blowing port is formed below the discharging port, air blowing is conducted for conducting gravity sorting on impurity particles which are similar to the grain granularity but different in proportion, and a screen p