Adjustable spray pipe outer cover mechanism

The invention belongs to the field of aero-engine nozzles, and particularly relates to an adjustable nozzle outer cover mechanism. Comprising an expansion adjusting sheet 7, a convergence adjusting sheet 10, a pull rod 5, an outer cover rear section 1, an outer cover middle section 2 and an outer cover front section. According to the adjustable spray pipe outer cover mechanism, a spray pipe actuating mechanism pushes an expansion adjusting piece 7 and a contraction adjusting piece 10 to move, one end of a pull rod 5 rotates around a hinge hole of the expansion adjusting piece 7, the other end of the pull rod 5 slides along a sliding way of a sliding rail 6, the pull rod 5 drives an outer cover middle section 2 to move, and the tail end of a second outer cover front end 3 is always attached to the front end of the outer cover middle section 2 due to inward torsion of a torsion spring 8. The adjustable spray pipe outer cover mechanism can be applied to a two-dimensional thrust vectoring spray pipe, moves along