Model Code Definition

D664 = NG25 ISO4401 mounting dimension, ServoJet jet-pipe pilot, built-in amplifier + full-range LVDT spool closed-loop feedback, high-flow D660 subseries

4406 = Factory preset zero-overlap four-way spring-centered metering spool with fixed original flow gain, null position fully calibrated during OEM production, standard factory amplifier parameter setting without K customized circuit modification

Technical Specifications

Hydraulic Parameters

Rated Flow:402 L/min @35bar single-side differential pressure; peak instantaneous flow 1485 L/min @70bar supply differential pressure

Max Working Pressure:P/A/B main control ports up to 350bar; internal T drain ≤210bar; external Y drain full 350bar permissible working pressureMoog Inc.

100% Full Stroke Step Response:≤31ms under nominal 210bar supply hydraulic pressure

Control Precision:Hysteresis＜0.28%FS, Resolution＜0.078%FS, total thermal drift(-20~+80℃)＜2.4%FS

Null Leakage:0.32~1.95 L/min subject to factory spool machining tolerance

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

Net Weight:5.59kg

Electrical Parameters

Input Power Supply:24VDC wide input range(18~32VDC), quiescent standby current ≤910mA

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

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

EMC Standard:Compliant with EN55011 industrial electromagnetic compatibility specification

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, standard X pilot port blocked with factory blank plug for non-external pilot oil setup

Electrical Interface:11-pin circular socket integrates 24V power supply, ±10V 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 outperforms traditional nozzle-flapper pilot on anti-pollution performance, ensuring long-term stable continuous running under moderately contaminated hydraulic oil of metallurgical workshopsMoog Inc..

2.Standard fixed-gain built-in amplifier with factory original calibration; four-way zero-lap spool realizes high-precision closed-loop position/speed/force control for rolling mill and heavy forging equipment; onboard LVDT dynamically compensates spool drift caused by ambient temperature fluctuation.

3.Spring-centered fail-safe neutral layout: main spool automatically returns to middle position upon power failure to isolate A/B oil circuits and lock hydraulic cylinder, preventing unexpected equipment malfunction and roller runaway.

4.Original factory fixed gain matches regular cyclic load of metallurgical production lines; ±10VDC analog input owns outstanding anti-interference property for long-distance field wiring under harsh industrial environment.

Typical Application

Hot & cold rolling mill roll gap closed-loop servo control, strip thickness AGC automatic adjusting system of continuous rolling line, large slab hydraulic compression equipment, heavy-duty forging master cylinder flow precision regulation, hydraulic component fatigue test bench, large metal extrusion forming machinery.

Installation & Maintenance Instructions

1.Install 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 independent 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 4406 edition are fully pre-calibrated at MOOG factory; only minor on-site potentiometer fine-tuning is permitted; complete disassembly of ServoJet pilot assembly and main spool unit is strictly forbidden.

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