| 摘要 |
<p>Hydraulic valves such as hydraulic flow control valves, pressure regulating valves, and servo valves are all formed with metering passageways which reduce and eliminate their susceptibility to electro-kinetic corrosion erosion that occurs at very low flow when the valves are in their null position or nearly shut off. The metering passages and the metering edges comprising the overall metering passageways are shaped to favorably control the flow characteristics of phosphate ester based fluids, which, if not controlled favorably would produce severe electrokinetic streaming current and its wall current, which would induce electrokinetic corrosion erosion. The shapes and dimensions of the metering passages and metering edges are derived from the results of a mathematical quantitative analysis. In one embodiment of a hydraulic valve, the sleeve, i.e. the non moving member, of the relatively moving metallic hydraulic valve components, has the orifice of the intake passageway, which thereby is serving as part of a hydraulic fluid metering passageway, formed with a rounded metering edge, when viewed in a geometric plane parallel to the axis of the intake passageway, and also formed with spaced parallel metering sides joined at each of their spaced ends by curved corners, and tangent thereto, also by concave metering end edges, formed on the arcs of circles, when viewed in a geometric plane perpendicular to the axis of the intake passageway. Also in this embodiment, the slide, i.e. the moving member movable at right angles to the intake passageway, has its leading cylindrical circumferential edge, which thereby is serving as part of a hydraulic fluid metering passageway, formed with a rounded metering edge.</p> |
