Model Code Definition

D664：NG25 ISO4401 Size08 mounting specification, two-stage ServoJet pilot, built-in amplifier + full-travel LVDT spool closed feedback, large-flow main valve body of D660 series

Z：Non-standard tailor-made spool contour, factory flow bench calibrated gain and null parameters, customized amplifier circuit setting outside standard catalogue

4382：Underlap four-way spring-centred spool structure, non-zero overlap design, fixed customized flow linearity and neutral bias value

K：Standard high-temperature FKM composite sealing material, conventional internal drain channel layout, general mineral hydraulic oil adaption

Technical Specifications

Hydraulic Parameters

Rated Flow：385 L/min at 35bar single-side differential pressure across spool lands; peak instantaneous flow 1280 L/min under 70bar supply differential pressure

Max Working Pressure：Main P/A/B ports 350bar; internal T drain ≤210bar; independent external Y drain full 350bar allowable working pressure

Full Stroke Step Response：≤27ms at nominal 210bar supply oil pressure

Control Precision：Hysteresis＜0.25%FS, Resolution＜0.07%FS, total thermal drift＜2.2%FS within rated working temperature range

Null Leakage：0.25~1.85 L/min determined by original spool machining precision

Working Medium：Anti-wear mineral hydraulic oil, fluid cleanliness NAS6~7 / ISO4406 17/14/11, operating fluid temperature -20℃~+80℃

Net Weight：5.82kg

Electrical Parameters

Input Power：24VDC wide-range power input (18~32VDC), static standby quiescent current ≤860mA

Default Control Signal：Factory standard ±10VDC differential analog input; optional ±10mA / 4~20mA current control upon special order

Connector：Standard 11-pin shielded circular aviation plug with IP65 protection grade, EMC EN55011 certified

Port & Connection Configuration

Hydraulic Interface：Standard ISO4401 NG25 P/A/B/T/Y port layout; internal pilot oil supply as factory default, X pilot port sealed with original plug; K standard mounting gasket pre-assembled; separated T/Y independent drain design, all spare drain ports equipped with factory sealing plugs

Electrical Interface：Built-in socket integrates 24V power supply, analog command signal and full-range LVDT feedback wiring; double-shielded control cable required with single-point cabinet grounding, no fieldbus communication function

Core Functions

1.Patented ServoJet jet-pipe pilot construction owns superior dirt resistance compared to traditional nozzle-flapper pilot, guarantees long-term steady running under moderately contaminated workshop hydraulic oil environment.

2.Z custom underlap spool matches K standard FKM sealing to restrain zero drift under normal ambient temperature variation, realizes high-precision closed-loop position, clamping force and speed regulation of hydraulic actuator.

3.Spring-centered fail-safe neutral mechanism: main spool automatically returns to middle position after power cut to block A/B oil paths and lock hydraulic cylinder, preventing unexpected equipment runaway failure.

4.K standard fluorine rubber seal features good anti-aging and oil corrosion resistance, stable sealing performance under long-period cyclic load operation of general industrial hydraulic medium.

Typical Application

Heavy forging hydraulic press main cylinder servo control, steel rolling auxiliary hydraulic servo system, non-ferrous metal extrusion forming equipment, industrial hydraulic fatigue test bench, medium-tonnage die-casting machine closed-loop hydraulic control.

Installation & Maintenance Instructions

1.Mount 3μm precision high-pressure inline filter on upstream P inlet pipeline; replace filter cartridge after first 15 working days of equipment commissioning startup.

2.Power cable and shielded control wire must be arranged in separated wiring ducts to avoid frequency converter electromagnetic interference; fix valve with specified bolt torque complying with ISO08 installation dimension.

3.All flow gain, null offset and onboard amplifier parameters are pre-calibrated at MOOG factory; only tiny on-site potentiometer fine adjustment is allowed; complete disassembly of ServoJet pilot and main spool assembly is strictly forbidden.

4.K standard FKM sealing cannot be replaced with ordinary NBR rubber seal; for spare part storage, fully block idle T/Y drain ports with original plugs and preserve in dry dustproof warehouse to avoid seal deterioration and oil leakage.