Model Code Definition

D664 = NG25 ISO4401 mounting dimension, ServoJet jet-pipe pilot structure, onboard integrated amplifier + full-range LVDT spool closed-loop feedback, large-flow D660 sub-series

4747 = Factory preset zero-overlap four-way spring-centered metering spool with exclusive optimized flow gain, null position fully OEM pre-calibrated, standard amplifier circuit without K-type customized modification

Technical Specifications

Hydraulic Parameters

Rated Flow:492 L/min @35bar single-land differential pressure; peak instantaneous flow 1660 L/min @70bar supply differential pressure

Max Working Pressure:P/A/B main ports up to 350bar; built-in T drain ≤210bar; external Y drain supports full 350bar rated pressureMoog Inc.

Full Stroke Step Response:≤27.5ms under nominal 210bar supply oil pressure

Control Precision:Hysteresis＜0.23%FS, Resolution＜0.065%FS, overall thermal drift(-20~+80℃)＜2.0%FS after factory gain fine calibration

Null Leakage:0.25~1.79 L/min depending on original spool machining tolerance

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

Net Weight:5.76kg

Electrical Parameters

Input Power Supply:24VDC wide input range(18~32VDC), static standby current ≤865mA

Default Control Command:Factory standard ±10VDC differential analog input; ±10mA /4~20mA current signal available via factory custom modificationMoog Inc.

Connector:11-pin circular aviation receptacle, IP65 protection after complete cable assembly

EMC Compliance:Conforms to EN55011 industrial electromagnetic compatibility standard

Port & Connection Configuration

Hydraulic Interface:ISO4401 NG25 standard hole layout including P supply port, A/B actuator control ports, separated built-in T internal drain and dedicated Y external drain; pre-installed original NBR mounting gasket, unused X pilot port sealed with factory blank plug for non-external pilot oil application

Electrical Interface:11-pin circular socket integrates 24V power supply, ±10V command signal and full-travel 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 owns superior contamination resistance versus traditional nozzle-flapper pilot, ensuring continuous stable operation under medium-impurity hydraulic oil of metallurgical production site and test laboratory.

2.Optimized fixed flow gain of 4747 spool matches high-precision large-flow closed-loop control demand; four-way zero-lap spool achieves accurate position/speed/force closed-loop adjustment for hot/cold rolling mill and heavy forging master cylinder; onboard LVDT automatically compensates temperature-induced spool drift.

3.Spring-centered fail-safe neutral design: main spool returns to middle position automatically once power fails to block A/B oil circuit and lock hydraulic actuator to avoid unexpected equipment runaway damage.

4.Factory pre-calibrated built-in amplifier features strong anti-interference performance to adapt long-distance analog wiring under harsh industrial environment.

Typical Application

Hot & cold continuous rolling mill AGC roll gap closed-loop servo control, heavy slab hydraulic forging press cylinder precise flow regulation, full-scale hydraulic component fatigue test bench, large aluminum/steel extrusion forming equipment, marine hydraulic servo test system.

Installation & Maintenance Instructions

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

2.Arrange power cable and shielded control wire inside separated wiring ducts to avoid inverter harmonic interference to analog control signal; fasten valve with factory specified bolt tightening torque and standard flat washers.

3.Flow gain and null offset parameters of standard 4747 version are fully pre-set at MOOG factory; only minor on-site potentiometer fine-tuning is permitted; full disassembly of ServoJet pilot assembly and main spool unit is strictly prohibited.

4.Seal unused spare T/Y drain ports with original factory blank plugs during spare part storage; store valve in dry dustproof warehouse to prevent NBR rubber seal ageing and subsequent oil leakage.