ELECTROHYDRAULIC REGULATING DRIVE

摘要

There is described an electrohydraulic regulating device comprising a regulating cylinder, a regulating piston in the cylinder capable of being loaded at either end thereof for repositioning the piston in the cylinder. A pair of magnetically operable valves are connected to opposite ends of the cylinder, each of the valves also being connected to both supply and return conduits for conducting pressurized hydraulic fluid from a supply thereto and for returning hydraulic fluid to a reservoir therefrom, respectively. The valves are operable to alternatively effect fluid communication between the respective supply and return conduits connected thereto and the respective end of the cylinder connected thereto to alternatively conduct hydraulic fluid to and from the respective end of the cylinder connected thereto. A computer is operable to produce switch pulses of variable duration to operate the valves to effect corresponding adjustments in the relative position of the piston in the cylinder. Also included is a pair of restrictors, one of the restrictors being in one of the supply and return conduits connected to each of the valves, both of the restrictors being in the same respective conduits relative to the respective valves, whereby, when the valves are operated to effect piston adjustments, the pressure drop in the fluid between the valves is minimized to minimize the effects of the compressibility of the fluid and thereby permit enhanced accuracy in the adjustments. Finally, there is provided a pair of pressure sensors. One of the sensors is connected to the respective conduit of the device between each of the restrictors and the adjacent valve to detect a pressure change therein. Each of the sensors is also connected to the computer for transmitting a signal thereto in response to the pressure change to indicate the operation of the adjacent valve.