G771K203A G77X/- 77x系列流量控制伺服阀

G771K203A

The G77X/-77XSeries flow control servo valves arethrottle valves for 3 and preferably 4-way applications.They are a high performance, 2-stage design that coversthe range of rated flows from 4 to 57 l/min (l to 15 gpm) at210 bar (3000 psi) valve pressure drop per spool land.
The output stage of the valve is a closed center, four-waysliding spool. The pilot stage is a symmetrical double-nozzleand flapper, driven by a double air gap, dry torque motor.Mechanical feedback of spool position is provided by acantilevered spring,The valve design is simple and ruggedfor dependable, long life operation.
These valves are suitable for electrohydraulic position,speed, pressure or force control systems with high dynamicresponse requirements.The G77X/-77Xis ideally suited forapplications where superior dynamics are a must.
Intrinsically safe valve versions are available for use inapplications with potentially hazardous environments.Specific models are certified to FM, ATEX, CSA, TllS andIECEx standards.

The G77X/-77XSeries is proven technology that performsreliably in machines where high performance,stability andaccuracy are required.Moog’s Mechanical Feedback Valvesare designed to provide high reliability and long service life.

The G77X/-77XSeries Flow Control Servo Valve consistsof a polarized electrical torque motor and two stagesof hydraulic power amplification. The motor armatureextends into the air gaps of the magnetic flux circuit andis supported in this position by a flexure tube. The flexuretube acts as a seal between the electromagnetic andhydraulic sections of the valve. The 2 motor coils surroundthe armature, one on each side of the flexure tube.
The flapper of the first stage hydraulic amplifier is rigidlyattached to the midpoint of the armature. The flapperextends through the flexure tube and passes between2 nozzles, creating two variable orifices between thenozzle tips and the flapper. The pressure controlled by theflapper and nozzle variable orifice is fed to the end areasof the second stage spool.

The second stage is a conventional four-way spool design inwhich output flow from the valve, at a fixed valve pressuredrop,is proportional to spool displacement from the nullposition, A cantilevered feedback spring is fixed to theflapper and engages a slot at the center of the spool.Displacement of the spool defects the feedback springwhich creates a force on the armature/flapper assembly.
Input signals induce a magnetic charge in the armatureand cause a deflection of the armature and flapper.Thisassembly pivots about the flexure tube and increases thesize of one nozzle orifice and decreases the size of theother.
This action creates a differential pressure from the one endof the spool displacement causing a force in the feedbackwire which opposes the original input signal torque. Spoolmovement continues until the feedback wire force equalsthe input signal force.