Abstract: An electromagnetic switching-valve position detection system includes: an electric current control circuit in which an electric current from a power supply is smoothed to be a direct current, and is turned into a pulse wave alternating current, the pulse wave alternating current being transmitted to the secondary side and outputted as a smoothed direct current; a carrier wave generator configured to superimpose a high frequency carrier wave for position detection on a signal wave of the electric current command; and a detecting unit configured to extract a carrier wave frequency component for the position detection from a voltage feedback signal of the solenoid, detect a voltage amplitude from the frequency component, and obtain an amplitude signal. The control unit has a position determining unit configured to determine a position of the valve spool, and a determination circuit configured to output a valve position signal based on the determination signal.

Abstract: A hydraulic device with the position sensor feedback-controlled by a servo amplifier on the basis of a deviation between a command value of a command signal and a position sensing value from a position sensor includes: a computation processing section that outputs the position sensing value as a sensing signal; a communication device that transmits the sensing signal to the servo amplifier, and receives a signal from the servo amplifier; and a storage section storing characteristics information of the hydraulic device to be read via the communication device. The characteristics information at least includes: calibration information which is measured and acquired in advance in a test stand in a manufacturing process of the hydraulic device, and includes a position sensing value from the position sensor and a characteristics value of the hydraulic device, associated with each other; and flow rate characteristics information including a flow rate of the hydraulic device.

Abstract: A bipolar current control drive circuit for an inductive load includes a switching power supply circuit in which an alternating current from a power supply is formed to a direct current smoothed through a rectifier bridge diode and a primary smoothing capacitor, the current is transmitted to a secondary side using a switching transformer, and the current is formed to a direct current. The switching transformer includes a first secondary coil and a second secondary coil for one primary coil to form alternating currents from the secondary coils to direct currents in reverse orientations and output the currents to an inductive load. A polarity control circuit controls switching between closing and opening of a first secondary switching element and a second secondary switching element and controls the polarity of an electric current.

Abstract: An electromagnetic switching-valve position detection system includes: an electric current control circuit in which an electric current from a power supply is smoothed to be a direct current, and is turned into a pulse wave alternating current, the pulse wave alternating current being transmitted to the secondary side and outputted as a smoothed direct current; a carrier wave generator configured to superimpose a high frequency carrier wave for position detection on a signal wave of the electric current command; and a detecting unit configured to extract a carrier wave frequency component for the position detection from a voltage feedback signal of the solenoid, detect a voltage amplitude from the frequency component, and obtain an amplitude signal. The control unit has a position determining unit configured to determine a position of the valve spool, and a determination circuit configured to output a valve position signal based on the determination signal.

Abstract: A bipolar current control drive circuit for an inductive load includes a switching power supply circuit in which an alternating current from a power supply is formed to a direct current smoothed through a rectifier bridge diode and a primary smoothing capacitor, the current is transmitted to a secondary side using a switching transformer, and the current is formed to a direct current. The switching transformer includes a first secondary coil and a second secondary coil for one primary coil to form alternating currents from the secondary coils to direct currents in reverse orientations and output the currents to an inductive load. A polarity control circuit controls switching between closing and opening of a first secondary switching element and a second secondary switching element and controls the polarity of an electric current.

Abstract: Disclosed is a solenoid type electromagnetic operating device which needs a relatively large current only for a limited short period at an excitation start initial stage and is adapted to achieve the speeding up at an excitation start stage and an improvement in responsiveness as well as power saving without increasing a power load on each of a drive circuit and power supply.