Study Of Torque Motor Static Characteristics With Magnetic Fluid

As the electric-mechanism converter of the servo valve, torque motor is the key component of the electro-hydraulic servo valve. Its output torque characteristic has a significant influence on the performance of servo valve. Based on the special property of magnetic fluid (MF), we fill the magnetic fluid into the working clearances of the servo valve torque motor. One side, the magnetized magnetic fluid can exert a damping torque on the torque motor armature and reduce vibration of the armature; on the other side, it can improve the magnetic circuit efficiency of the torque motor because of the magnetic fluid's larger magnetic permeability. This paper brings forward a method of improving torque motor static characteristics with the application of magnetic fluid, and investigates static characteristics of torque motor with MF and without MF.Firstly, this paper proposes the mathematical model and finite-element analysis model of torque motor with MF and without MF. Secondly, the electromagnetic field of torque motor is analyzed using the Ansoft Maxwell software; static output torque of torque motor with MF and without MF is calculated. Then the rotary angle of torque motor with different input electric current and MF is measured using three-coordinate measurement device. At last, this paper derives the rules of damping torque due to magnetic fluid in the working clearances of torque motor and lays the groundwork for the study of torque motor dynamic characteristics and servo valve characteristics.