Analysis of the Dynamic of Vector Nozzle Adjustment Mechanism Considering the Effect of Joint Clearance

IntroductionThe axisymmetric vector nozzle is an important mechanism to realize thrust vectoring technology, which is a complex spatial multilink mechanism, consisting of multi-stage linkage driven by multiple actuators. Under the action of the actuator load, there is resistance between all levels of linkage, which is prone to phenomena such as stagnation and poor adjustment accuracy, and thus affects the reliability of the aero-engine.Materials and methodsA single-link dynamics model of the vector nozzle regulating mechanism is constructed by using Lagrange equations of the first kind. According to the above whole chain vector nozzle adjustment mechanism, three actuators are evenly distributed on one side of the ring, and 12 branch chains are evenly distributed on the right side, and the whole machine model of the vector nozzle adjustment mechanism is constructed. Due to the fact that all branched chains have the same structure and working principle, only four branched chains are analyzed in this paper.ResultsThe correctness of the dynamic model is verified by comparing the ADAMS simulation results with the numerical simulation results. The simulation results show that the presence or absence of clearance in the single-chain structure has the greatest influence on the motion joint 3. The force on the four joints is almost the same when the mechanism is doing the retracting and expanding motion, and the collision force on joint C is the largest when it is doing the deflecting motion, followed by A, B and D are almost the same with the smallest force. The effect of changing the joint clearance on the retardation force of the three actuators when doing retracting and deflecting motions is also considered. At last, the results show that the clearance will produce wear, and the larger the clearance, the greater the depth of wear and the more intense the degree of wear.ConclusionThe results show that the model presented in this paper can simulate the vector nozzle regulating mechanism well.