Rear duct ejector provided with circumferentially tightly covered valve body

The invention discloses a rear duct ejector provided with a circumferentially tightly covered valve body. The rear duct ejector comprises an outer casing, a pair of hydraulic actuating cylinders, a pair of hydraulic actuating rods, a pair of cranks and a pair of spherical hinge connecting rods, wherein the pair of hydraulic actuating cylinders, the pair of hydraulic actuating rods, the pair of cranks and the pair of spherical hinge connecting rods are separately mounted symmetrically about the center of a plane, the valve body actuating circumferentially and an inner casing. According to the technical scheme, the external duct outlet area of a variable cycle engine can be adjusted; a circumferential sliding groove is formed between the valve body and the inner casing in a fit manner, so that opening and closing of an air flow channel can be achieved by circumferential rotation; and the valve body is an integral valve body which is tightly closed circumferentially, rather than a plurality of valve body sheets