| 摘要 |
FIELD: mechanical engineering. ^ SUBSTANCE: invention relates to positive-displacement hydraulic drives of construction and road-building machines from high-pressure overloads. Proposed valve has housing in form of stepped hollow bushing with threaded section and seals on outer mounting surfaces, radial outlet and central inlet channels, main, make-up and auxiliary shutoff members, inner chamber and radial holes for connection with drain space. Main shutoff member has cylindrical and conical parts and axial throttling hole. Auxiliary shutoff member has cone-shaped sealing surface and outer ring two side step-bead. The latter takes up load of coil compression spring. Spring thrust by its opposite end against support end face of valve regulating member. Valve is made in form of unit-module designed for building-in directly into housing of hydraulic drive and is formed by two automatic control devices arranged coaxially in central channel of housing, mechanically intercoupled and successively interacting to control shutoff members with common control pressure chamber. Said chamber is hermetically arranged between said devices to provide communication through throttle with control pressure source. Device to control main and make-up shutoff members consists of housing with main seat with intake and drain spaces and main and make-up shutoff members separating the spaces. Shutoff members are spring-loaded relative to control device of auxiliary shutoff member and are made integral, in form of plunger with inner through multistep bore. Plunger is installed for reciprocating in guide bore of housing and simultaneous contacting and engaging through conical sealing part with seat of inlet channel of housing, and inner of larger step, with sealing piston part of housing of auxiliary shutoff member. Housing of the latter is secured motionlessly in threaded bore of housing. Control device of auxiliary shutoff member is made in form of separate unit-module for building into threaded bore of housing to form circular drain space and passing of medium in one direction. Said device has housing in form of threaded bushing sealed over mounting surfaces with guide piston cylindrical part and dividing outer ring groove with radial through channels. Stepped cylindrical bore section of threaded surface and seat in bore of smaller step is made inside bushing. Bores accommodate auxiliary shut-off member with axial outer shank of cylindrical form with spherical support and mounting end face. End face is coaxially brought out into zone of control pressure common chamber. Shutoff member is installed for simultaneous contact through its conical part with seat of bushing, and through peripheral surface of ring two-side step, with surface of larger step bore. Longitudinal through semicylindrical bores uniformly spaced over circumference are made on ring step. Depth of bores is arranged out of zone of contact of conical surface of shutoff member and seat of threaded bushing. Shank of auxiliary shutoff member is installed in bore of bushing smaller step with guaranteed ring clearance to pass working medium. Said mechanical coupling is made in form of stepped cylindrical indicator rod-pusher with guide outer part provided with two-side step and coaxial end face bore-seat with central through throttling hole arranged in inner bore of smaller step of main shutoff member. Pusher is installed for axial displacement and engagement through end face bore with spherical surface of shank of auxiliary shutoff member. ^ EFFECT: improved operation reliability, manufacturability and repairability of valve. ^ 7 cl, 6 dwg
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