美国摩根伺服阀G761系列样本

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美国摩根伺服阀G761系列样本G761 SERIES SERVOVALVES
The G761 Series flow control
servovalves are throttle valves
for 3- and preferably 4-way
applications.They are a high
performance， two-stage design
that covers the range of rated
flows from 1 to 16.5 gpm at
1000 psi valve drop.The
output stage is a closed center，
four-way， sliding spool.The pilot
stage is a symmetrical double-nozzle and flapper， driven by a
double air gap， dry torque
motor. Mechanical feedback of
the spool position is provided
by a cantilever spring.The valve
design is simple and rugged for
dependable， long life operation.
These valves are suitable for
electrohydraulic position，
speed， pressure or force con-trol systems with high dynamic
response requirements.
Principle of operation
An electrical command signal
(flow rate set point) is applied
to the torque motor coils and
creates a magnetic force， which
acts on the ends of the pilot
stage armature.This causes a
deflection of armature/flapper
assembly within the flexure
tube. Deflection of the flapper
restricts fluid flow through one
nozzle， which is carried through
to one spool end， displacing
the spool.
Movement of the spool opens
the supply pressure port (P) to
one control port， while simul-taneously opening the tank
port (T) to the other control
port.The spool motion also
applies a force to the cantilever
spring， creating a restoring
torque on the armature/flapper
assembly. Once the restoring
torque becomes equal to the
torque from the magnetic
forces， the armature/flapper
assembly moves back to the
neutral position， and the spool
is held open in a state of equi-librium until the command sig-nal changes to a new level.
In summary， the spool position
is proportional to the input
current.With constant pressure
drop across the valve， flow to
the load is proportional to the
spool position