Electromagnetic switching-valve position detection system

Abstract

This electromagnetic switching-valve position detection system is provided with: a current control circuit that obtains a smoothed direct current by smoothing a current from a power source via a rectifier bridge diode and a primary-side smoothing capacitor, that transmits the direct current to the secondary side by a switching transformer as an alternating current of pulse waves from a switching element where switching is controlled in accordance with a pulse signal from a pulse signal generation device, and that outputs same as a direct current that has been smoothed via a secondary-side diode and a secondary-side capacitor; a carrier wave generation device for superimposing high-frequency carrier waves for position detection onto signal waves of a current command; and a detection unit for extracting a frequency component of the carrier waves from a voltage feedback signal of a solenoid, and detecting a voltage amplitude thereof to obtain an amplitude signal. A control unit further comprises: a position determination unit for determining a valve spool position on the basis of the amplitude signal and preset criterion reference values corresponding to respective valve spool positions, and outputting a determination signal; and a determination circuit for outputting a valve position signal on the basis of the determination signal.

Description

technical field [0001] The present invention relates to a system for detecting the position of an electromagnetic switching valve by detecting the position of a spool valve without using a position detection sensor. Background technique [0002] In the electromagnetic switching valve used in the hydraulic system, the coil of the solenoid is generally energized to make the movable iron core move toward the fixed iron core, so that the position of the valve core linked with the movable iron core is in the axial direction. The upward displacement and the port connection are switched, switching the flow path of the hydraulic circuit. [0003] Examples of such electromagnetic switching valves include a single solenoid type including one solenoid at one end of the valve element, and a double solenoid type including a pair of solenoids at both ends of the valve element. In the single solenoid type, in general, the so-called spring bias type in which the spool returns to a predeter...

AI Technical Summary

Problems solved by technology

[0005] In order to improve the reliability of the switching movement of the solenoid-based spool, the above-mentioned detection mechanism and sensor are required, but since these devices are installed, the electromagnetic switching valve Overall lengthening and large-scale are unavoidable

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