Performance Study Of Feedback Torque Motor For (2D) Valve

The electro-hydraulic servo or proportional valve is an important executive component of the electro-hydraulic control system,which is the link between the hydraulic part and the electrical part.It has always been the core research object of the fluid transmission,and plays a key role in the performance of the entire hydraulic system.With the development of national economy,the role of electro-hydraulic servo and proportional control technology in industrial production,aerospace science and technology,mining and metallurgy,national defense and military and other fields has been continuously deepened.As the driving element of hydraulic valve,the static and dynamic characteristics of electro-mechanical converter have a great influence on the performance of electro-hydraulic proportional valve / servo valve.In this paper,a new type of electro-mechanical converter with direct feedback characteristic is proposed.(1)The structure and working principle of the two-dimensional(2D)valve feedback torque motor are analyzed,and compared with the existing common torque motor,it is proposed that it has force displacement feedback characteristics.Connected with the valve core,the armature axial movement can obtain the feedback electromagnetic torque,which is conducive to the realization of the two degrees of freedom movement of the hydraulic valve.It is proposed that the external structure of the torque motor coil not only ensures the sufficient rotating space of the armature,but also optimizes the space proportion of the permanent magnet and the excitation coil.(2)Based on the classical electromagnetic theory,the magnetic circuit of the feedback torque motor is analyzed.Maxwell equations are used to solve the basic laws of electromagnetic field,and Dirichlet boundary condition and Neumann boundary condition are added to describe the static magnetic field characteristics of feedback torque motor.Using the finite element software Anosft Maxwell,the magnetic field distribution,driving characteristics and feedback characteristics of the torque motor under different working conditions are calculated.(3)The static and dynamic experiments of three different angle feedback torque motors are carried out on the test bench.The driving torque angle characteristics and feedback torque displacement characteristics are tested under different ampere turns.The step response and dynamic response of the torque motor are tested.The experimental results are basically consistent with the theoretical analysis data,which shows that the torque motor meets the requirements of 2D valve.(4)Optimize the electromagnetic stiffness of the feedback torque motor,further improve the output characteristics,mainly through adding magnetic fluid,reasonably reducing the working air gap,and optimize the magnetic steel structure.The effect of the optimized coefficient on the driving torque and feedback torque is analyzed.