LAUSR

In most servo valve control systems, the flow force is a critical factor influencing the control precision of the servo valve, especially in the pilot stage. In this paper, the generating mechanism of the flow force in the pilot stage is analyzed, showing that it is mainly generated by the impacting jet. Then, a three-dimensional numerical model of the deflector servo valve is built, and the pressure distribution on the deflector is simulated under different offsets. Due to the complicated structure of the deflector jet valve, it is impossible to measure the flow force directly. Thus, an indirect method is proposed for the flow force measurement. Compared with the theoretical analysis and the simulation results, it is found that the indirect method can be an effective way to get a reliable relationship between the flow force and the deflector offsets. The experiment shows the flow force increases linearly with the deflector offsets and the growth rate is 7.32×10 N/μm. Meanwhile, the maximum flow force can reach 0.0366N in working condition.