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设计了一种直动式二维(Two Dimensional,2D)电液压力伺服阀,采用2D伺服活塞机构产生液压力来驱动主阀芯运动,输出需要的负载压力。设计的2D伺服活塞机构采用直线位移传感器(Linear Variable Differential Transformer,LVDT)进行检测从而形成闭环位置反馈,精确控制2D活塞位移;主阀芯与2D伺服活塞通过弹簧连接,2D活塞在两侧压力差作用下运动,通过弹簧来对主阀芯施加作用,控制主阀阀口的开度,来精确控制输出的负载压力;为提高压力伺服阀的稳定性和可靠性,主阀阀芯根据挤压油膜缓冲理论进行了圆盘结构设计,以增大系统黏性阻尼。在建立该阀的数学模型的基础上,仿真分析了该阀的静动态特性,并通过设计样阀及实验研究,验证了该阀设计的可行性,实验结果表明:在系统压力28 MPa下,该阀的阶跃响应时间在30ms,其滞环<3%,线性度<2%,压力跟随特性和输出稳定性好;相较于传统直动式比例伺服压力阀,该阀的结构特点决定了其抗污染能力强,可靠性高,且质量和体积分别仅为同类伺服阀的1/5和1/7左右,非常适用于机载液压刹车系统。
A two dimensional (2D) electrohydraulic servo valve was designed. The 2D servo piston mechanism was used to generate hydraulic pressure to drive the main spool and output the required load pressure. The designed 2D servo piston mechanism is detected by a Linear Variable Differential Transformer (LVDT) to form closed-loop position feedback to precisely control the displacement of the 2D piston. The main spool and the 2D servo piston are connected by a spring, and the pressure difference of the 2D piston on both sides Under the action of the spring to exert the role of the main spool to control the opening of the main valve port to accurately control the output load pressure; in order to improve the stability and reliability of the pressure servo valve, the main valve spool according to squeeze Oil film buffer theory of the disc structure design to increase the system viscosity damping. Based on the mathematical model of the valve, the static and dynamic characteristics of the valve were simulated and analyzed. The feasibility of the valve design was verified by designing the sample valve and the experimental study. The experimental results show that under the system pressure of 28 MPa, The valve step response time of 30ms, the hysteresis <3%, linearity <2%, pressure follow-up characteristics and good output stability; compared to the traditional direct acting proportional servo valve, the structural characteristics of the valve decision Its anti-pollution ability, high reliability, and the quality and size of the servo valves are only 1/5 and 1/7, respectively, is very suitable for on-board hydraulic brake system.