BACKED-UP ELECTROHYDRAULIC DRIVE Russian patent published in 2004 - IPC

FIELD: automatic control systems.

SUBSTANCE: proposed drive contains housing with delivery and drive channels for working liquid, single-chamber hydraulic motor with space channels and series-connected electromagnetic cut-in - cross-feeding valve, electrohydraulic power amplifier and servo cylinder, hydraulic distributor with mechanical non-power run of drive connected with rod of servo cylinder and hydraulic systems change-over valve communicating with two independent hydraulic supply systems. Hydraulic systems change-over valve is provided with discrete-action automatic bypass devices with indicator rods and is made in form of two control devices opposite built into common cylindrical channel of housing and separated by bushing and provided with "valve-seat" locking elements, each consisting of cover, guide cup and support bushing with sealing rings on outer cylindrical surfaces and inner step bores secured in cover housing channel and mechanically interconnected spring-loaded disk nonreturn valve with bypass device installed in bores of support bushing, and spring-loaded plunger hermetically fitted in larger bore step guide cup and furnished with inner partition, at one side of which spring is mounted, and at other side operating control chamber is formed which can communicate with supply pressure main line and, through disk nonreturn valve, built into smaller step of guide cup bore, with pressure channel of operating mechanism. Bores of large steps of support bushings of both control devices are cross-fed and are placed in communication with drain channel of operating mechanism. Said mechanical circuit is made in form of axially movable piston-seat of nonreturn valve bypass device sealed over outer surface and placed in inner bore, stepped cylindrical indicator rod installed for axial displacement and interacting through its working end faces with end face surfaces of partition of plunger and shutoff member of nonreturn valve formed as flat plate gate with outer spherical guide part and lopped to sealing edges of piston-seat made in form of ring concentrically arranged knife projections. Groove between knife projections is made toroidal, with radius of circle forming the torus, equal to height of projection, and center of torus is located in plane of sealing edges of knife projections. Guaranteed ring clearance to pass working medium set between outer surface of small step of indicator rod and surface of inner bore of piston-seat.

EFFECT: increased reliability.

2 cl, 8 dwg