Analysis on Stiffness of Armature Assembly of Jet Pipe Servo Valve

The jet pipe servo valve is an advanced core component in the hydraulic control system, and analysis on stiffness of the servo valve armature assembly is very important for the establishment of the servo valve mechanical model. The jet pipe is regarded as a rigid body in most literature. In this paper, the stiffness of each part of armature assembly such as the jet pipe, the oil guiding tube, the adjusting wire, the spring pipe and the ear spring piece are calculated based on the integral method and superposition principle. The correctness of the calculation model of the jet pipe stiffness is verified based on the finite element analysis method. Through the parameter sensitivity analysis, the relative sensitivity of the equivalent stiffness of the jet pipe to its geometrical dimensions is obtained. It is found that the stiffness of the jet pipe is most sensitive to the outer diameter of the upper end and length of the pipe, sensitive to the outer diameter of the lower end, and insensitive to the diameter of the flow channel. Taking a certain type of jet pipe servo valve as an example, the dimensionless characteristics of the dimensions of the jet pipe are obtained.