ELECTROMAGNETIC CHANGEOVER VALVE POSITION DETECTION SYSTEM

摘要

To provide a position detection system capable of detecting a detection signal for reading a valve spool position change without the degradation after enabling an electromagnetic changeover valve to speed-up by current control of solenoid.SOLUTION: An electromagnetic changeover valve position detection system comprises: a current control circuit 10 in which a current from a power source is converted into a direct current that is smoothed via a rectifier bridge diode 11 and a primary side smoothing capacitor 12, and is transmitted to a secondary side by a switching transformer 16 as an alternating current of a pulse wave by a switching element 15 and outputted as smoothed DC through a secondary diode and a secondary capacitor; a carrier wave generator 30 which superimposes a high-frequency carrier wave for position detection on a signal wave of the current command; and a detection part 40 which extracts a frequency component of a carrier wave from a voltage feedback signal of a solenoid, detects a voltage amplitude to obtain an amplitude signal. A valve spool position is determined based on the amplitude signal and a determination reference value corresponding to each valve spool position, and a valve position signal is output.SELECTED DRAWING: Figure 1