Method for controlling electromagnetic proportional pressure control valve

摘要

In vibrating a spool of a spool-valve type electromagnetic proportional pressure control valve by applying a dither current so that no static friction acts on the spool, the dither effect tends to weaken in a region where the current is small and in a region where the current is so large as to cause magnetic saturation. An alternating dither current is superimposed on the current supplied to an electromagnet to vibrate the spool with an amplitude small enough not to affect the liquid pressure, and in a control region where the ratio of the solenoid force Fsol to the current I is small, the dither current is controlled so that its amplitude is larger or its frequency is lower than in other regions.