一、二种伺服阀前置级的比较图1为具有二个固定节流孔的正开口四通滑阀,圈2为双喷咀挡板阀,二者的结构形式虽然不同,但从实质上看,二者的组成、原理、功能和等效液压桥路却完全相同。从组成上看,二者都属于具有二个圈定节流孔、二个可变节流口的四通阀。只是图1为滑阀结构,阀口3和4为可变节流窗口; Comparison of Pre-stage and Pre-stage of Two Types of Servo Valves Figure 1 shows a positive opening four-way slide valve with two fixed throttles and a circle 2 with double nozzle flapper valves. Although the structure of the two is different, Point of view, both the composition, principle, function and equivalent hydraulic bridge are exactly the same. From a composition point of view, both belong to a four-way valve with two orifices and two variable restrictors. Figure 1 is only a slide valve structure, the valve orifice 3 and 4 for variable throttle window;