HIGH PERFORMANCE, TWO-STAGE DESIGN
PROVIDING FLOW CONTROL IN A SIMPLE,
RUGGED, DEPENDABLE, LONG LIFE DESIGN
WHAT MOVES YOUR WORLD
Rev. L, January 2014
SERVO VALVES
PILOT OPERATED
FLOW CONTROL VALVE
WITH ANALOG INTERFACE
G631/631 SERIES
ISO 4401-05-05-0-94
Moog G631/631 Series Flow Control Servo Valves
INTRODUCTION
2
Whenever the highest levels of motion control
performance and design flexibility are required, you’ll find
Moog expertise at work. Through collaboration, creativity
and world-class technological solutions, we help you
overcome your toughest engineering obstacles. Enhance
your machine’s performance. And help take your thinking
further than you ever thought possible.
INTRODUCTION
Product Overview 3
Features and Benefits 4
Description of Operation 5
TECHNICAL DATA
Performance Characteristics 6
Dynamic Characteristics 7
Electrical Data 8
Installation Drawings and
Null Adjust Instructions 9
Hole Pattern for Mounting Surface 10
BACKGROUND
Null Flow Adjustment 11
Flow Calculation and Null Cut Options 12
Related Products 13
Routine Maintenance Guidelines 14
About Moog 15
ORDERING INFORMATION
Accessories and Spare Parts 17
Ordering Code 18
This catalog is for users with technical knowledge. To ensure all necessary characteristics for function and safety of the system, the user has
to check the suitability of the products described herein. The products described herein are subject to change without notice. In case of doubt,
please contact Moog.
Moog is a registered trademark of Moog Inc. and its subsidiaries. All trademarks as indicated herein are the property of Moog Inc. and its
subsidiaries. For the full disclaimer refer to www.moog.com/literature/disclaimers.
For the most current information, visit www.moog.com/industrial or contact your local Moog office.
Rev. L, January 2014
TABLE OF CONTENTS
PRODUCT OVERVIEW
The G631/631 Series flow control servo valves are
throttle valves for 3 and preferably 4-way applications.
They are a high performance, 2-stage design that covers
the range of rated flows from 5 to 75 l/min (1.3 to 20 gpm)
at 35 bar (500 psi) valve drop per spool land.
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 spool position is pro vid ed by a
cantilever spring. The valve design is simple and rugged for
de pendable, long life op era tion.
These valves are suitable for electrohydraulic position,
speed, pressure or force control systems with high dynamic
response requirements.
Moog G631/631 Series Flow Control Servo Valves
INTRODUCTION
TIIS
Intrinsically safe valve versions are available for use in potentially hazardous environments. Specific models are certified to
FM, ATEX and CSA standards. Contact Moog for details.
Valve design 2-stage, with spool and bushing and dry torque motor
Mounting pattern ISO 4401-05-05-0-94
Maximum operating pressure to ports P, T, A, B 315 bar (4,500 psi)
Pilot stage Nozzle Flapper
Rated flow at ∆p
N
35 bar/spool land 5 l/min 10 l/min 20 l/min 40 l/min 60 l/min 75 l/min
(500 psi/spool land) (1.3 gpm) (2.5 gpm) (5 gpm) (10 gpm) (15 gpm) (20 gpm)
Step response time for 0 to 100% stroke with
spool and bushing design 18 ms 18 ms 18 ms 18 ms 18 ms 18 ms
3 Rev. L, January 2014
TIIS
Features Benefits
100% factory tested to ensure critical specification Ensures smooth and easy startup, reduces downtime and
performance insures long life in critical industrial applications
2-stage design Enables high machine performance, faster cycle times
and greater accuracy - all resulting in higher productivity
Dual Coil torque motor Redundancy for high reliability
Dual Precision Nozzles in Torque Motor Precision flow control and predictability
Dry torque motor design Eliminates potential contamination issues in the air gaps
of the torque motor that could cause machine downtime
Hardened 440C Bushing and Spool Provides for high life, wear resistance when used in the
harsh environments; provides for low sliding friction
during use
Emergency failsafe positioning Most valves are set up to return to a failsafe position
when the command signal is interrupted or eliminated
Field replaceable pilot stage filter Enables preventive maintenance in the field, saving
precious machine downtime and service costs
External null bias adjustment Enables technicians to manually adjust the null bias of the
valve to adapt to the conditions of the machine (see
section on null flow adjustment – Page 11). This feature
provides a simple adjustment to machine performance
without the need to adjust a controller.
FEATURES AND BENEFITS
The G631/631 Series is proven technology that performs
reliably in machines where high performance,
stability and accuracy are required. Moog’s Mechanical
Feedback Valves are designed to provide high reliability
and long service life.
Moog G631/631 Series Flow Control Servo Valves
INTRODUCTION
4 Rev. L, January 2014
DESCRIPTION OF OPERATION
The G631/631 Series Flow Control Servo Valve consists
of a polarized electrical torque motor and two stages
of hydraulic power amplification. The motor armature
extends into the air gaps of the magnetic flux circuit and
is supported in this position by a flexure tube member. The
flexure tube acts as a seal between the electromagnetic
and hydraulic sections of the valve. The 2 motor coils
surround the armature, one on each side of the flexure
tube.
The flapper of the first stage hydraulic amplifier is rigidly
attached to the armature. The flapper extends through the
flexure tube and passes between 2 nozzles, creating two
variable orifices between the nozzle tips and the flapper.
The pressure controlled by the flapper and nozzle variable
orifice is fed to the end areas of the second stage spool.
The second stage is a conventional four-way spool design in
which output flow from the valve, at a fixed valve pressure
drop, is proportional to spool displacement from the null
position. A cantilevered feedback spring is fixed to the
flapper and engages a slot at the center of the spool.
Displacement of the spool deflects the feedback spring
which creates a force on the armature/flapper assembly.
Input signals induce a magnetic charge in the armature
and causes a deflection of the armature and flapper. This
assembly pivots about the flexure tube and increases the
size of one nozzle orifice and decreases the size of the
other.
The differential pressure created by this action causes
spool motion. The resulting spool displacement induces a
linear force in the feedback wire which opposes the original
input signal torque. Spool movement continues until the
feedback wire force equals the input signal force.
Moog G631/631 Series Flow Control Servo Valves
INTRODUCTION
5 Rev. L, January 2014
T
A
P
B
X
View from ''T'' side
Spool
Feedback Wire
Flapper
Electrical Connector
Upper Polepiece
Inlet
Orifice
Flexure Tube
Coil
Armature
Lower Polepiece
Magnets (not shown)
Bushing
Pilot
Stage Filter
Electro-hydraulic Servo Valve Cut-away
Deviation of rated flow ± 10% of rated flow
Step response time for 0 to 100% stroke 18 ms
Threshold 1.0% of rated signal
Hysteresis < 3% of rated signal
Null shift at ∆ T = 38 °C (100 °F) < 4% of rated signal
G631/631 SERIES - SERVO VALVES
Moog G631/631 Series Flow Control Servo Valves
TECHNICAL DATA
6 Rev. L, January 2014
General Technical Data
Valve design 2-stage, with spool and busing and dry torque motor
Pilot stage Nozzle Flapper
Mounting pattern ISO 4401-05-05-0-94
Installation postion Any orientation, fixed or movable
Weight 2.2 kg (4.9 lb)
Storage temperature range -40 to +60 °C (-40 to +140 °F)
Ambient temperature range -40 to +135 °C (-40 to +275 °F)
Vibration resistance 30 g, 3 axis, 10 Hz to 2 kHz
Shock resistance 30 g, 3 axis
Seal material Fluorocarbon (FKM) 85 Shore A
Others upon request
Hydraulic Data
Maximum operating pressure to ports P, A, B, X 315 bar (4,500 psi)
Maximum operating pressure to port T 20% of pilot pressure, max 100 bar (1,450 psi)
Rated flow at p
N
35 bar/spool land (500 psi/spool land) 5, 10, 20, 40, 60, 75
Null adjust authority Greater than 10% of rated flow
Hydraulic fluid Hydraulic oil as per DIN 51524 parts 1 to 3 and ISO 11158
Other fluids on request.
Temperature range -40 to +60 °C (-40 to +140 °F)
Recommended viscosity range 10 to 85 mm
2
/s (cSt)
Maximum permissible viscosity range 5 to 1,250 mm
2
/s (cSt)
Recommended cleanliness class as per ISO 4406
For functional safety 19/16/13
For longer life 17/14/11
Recommended filter rating
For functional safety ß
10
≤ 75 (10 µm absolute)
For longer life ß
5
≤ 75 (5 µm absolute)
Static and Dynamic Data
G631/631 SERIES SERVO VALVES
Moog G631/631 Series Flow Control Servo Valves
TECHNICAL DATA
7 Rev. L, January 2014
100
20
40 50
30
10
0
0
25
50
75
Stroke (% of Rated Signal)
Time (ms)
Step Response Standard Frequency Response
3,000PSI DTE -24 at 38° C (100° F)
±25% Input Amplitude
0510 10050
90
70
50
30
10
+2
0
-2
-4
-6
-8
-10
Amplitude Ratio (Decibels)
Frequency (Hz)
Phase Lag (Degrees)
ELECTRICAL DATA
Moog G631/631 Series Flow Control Servo Valves
TECHNICAL DATA
8
Rev. L, January 2014
Rated current and coil resistance
A variety of coils are available for G631/631 Series Servo
Valves, which offer a wide choice of rated currents.
Coil impedance
The resistance and inductance of standard coils are
given below. The 2 coils in each Servo Valve are wound
with equal turns giving a normal production tolerance
on coil resistance of ±12 %. Copper magnet wire is
used, so the coil resistance will vary significantly with
temperature. The effects of coil resistance changes can be
essentially eliminated through use of a current feedback
servoamplifier having high output impedance.
Inductance is determined under pressurized operating
conditions and is greatly influenced by back electromagnetic
forces of the torque motor. These effects vary with
most operating conditions, and vary greatly with signal
frequencies above 100 Hz. The apparent coil inductance
values given are determined at 50 Hz.
Ordering code Coil inductance [H] Coil restance Power consumption [W]
Command signal [Ohms/coil at
25°C (77°F)]
Single coil Series coil Parallel coil Single coil Series coil Parallel coil
Q ±30 ±15 ±30 300 0.27 0.14 0.14
R ±100 ±50 ±100 28 0.28 0.14 0.14
Ordering code Coil inductance [H]
Measured at 50 Hz
Single coil Series coil Parallel coil
Q 2.0 7.0 2.0
R 0.2 0.8 0.2
Coil connections
A 4-pin electrical connector that mates with an
MS3106F14S-2S is standard. All 4 torque motor leads are
available at the connector so that external connections
can be made for series, parallel, or differential operation.
G631/631 Series Servo Valves can be supplied on special
order with other connectors or pigtail.
Configuration for valve opening P B, A T
A B C
DA
B C D
A B C D
Single Series Parallel
A (+), B (-) or C (+), D (-) A (+), D (-), B and C connected A and C (+), B and D (-)
Fluid:
Industrial hydraulic fluid per DIN 51524 parts 1 to 3 and
ISO 11158, maintained to ISO 4406 Code 19/16/13
recommended. Viscosity 10 to 85 mm
2
/s (cSt) at 38 °C
(60 to 300 SUS at 100 °F)
Operating Temperature Range:
Fluid: -40 to +60 °C (-40 to +140 °F)
Ambient: -40 to +135 °C (-40 to +275 °F)
Valve Phasing:
Flow out port B results when:
Series coils: B & C connected, A+, D-
Parallel coils: A & C connected, B & D connected, A+/B- or C+/D-
Single coils: A & C+, B & D-
Null Adjust:
Flow out port A results with the clockwise rotation of
the null adjust screw.
INSTALLATION DRAWINGS AND NULL ADJUST INSTRUCTIONS
5
PIN D
4
PIN C PIN B
3
2
PIN A
54.0
(2.126)
1
A B C D
A
D
B
C
46.0
(1.811)
70.0
(2.74)
135
(5.31)
119
(4.70)
106.40
(4.189)
58.0
(2.29)
121
(4.75)
127
(5.00)
97.30
(3.831)
77.0
(3.05)
22.99
(0.905)
6
Moog G631/631 Series Flow Control Servo Valves
TECHNICAL DATA
9
Rev. L, January 2014
1 Typical wiring schematic
2 Filter location
3 4X Ø 6.76 (0.266) thru Ø 11.10 (0.437) to depth shown Mounting Holes
4 Null adjust cover. Remove for screw access (requires 1/8” hex key)
5 Connector mates with MS3106F14S-2S (Moog P/N: -49054F014S002S)
6 Optional Manual Override
G631/631 SERIES HOLE PATTERN FOR MOUNTING SURFACE
B
F4
F4 F3
F2
A
T
P
Y
X
X
Notes
1. Surface to which the valve is mounted requires flatness
of 0.03 mm (0.001 in) over 100 mm (3.94 in) and an
average finish R
a
better than 0.8 µm (0.000032 in).
2. Ports:
P and T: 10 mm (0.390 in) diameter, counter-bored
15.75 mm (0.620) in) by 1.5 mm (0.061 in) deep
A and B: 9 mm (0.344 in) diameter, counter-bored
15.75 mm (0.620 in) by 1.5 mm (0.061 in) deep
X: 7.5 mm (0.295 in) diamter, counter-bored
11.75 mm (0.463 in) by 1.5 mm (0.061 in) deep
Designation P A B T X F1 F2 F3 F4
Size Ø mm 11.13 11.13 11.13 11.13 3.18 M6 M6 M6 M6
in 0.438 0.438 0.438 0.438 0.125 1/4-20 1/4-20 1/4-20 1/4-20
Position X mm 27.0 16.69 37.31 3.20 -10.59 0 54.0 54.0 0
in 1.063 0.657 1.469 0.126 -0.417 0 2.126 2.126 0
Position Y mm 6.32 21.41 21.41 32.51 7.39 0 0 46.02 46.02
in 0.249 0.843 0.843 1.280 0.291 0 0 1.812 1.812
Moog G631/631 Series Flow Control Servo Valves
TECHNICAL DATA
10 Rev. L, January 2014
Conversion Instruction
For operation with internal or external pilot connection.
Pilot flow supply Screw and seal washer location (M4 X 6 DIN EN ISO 4762)
X P
Internal P closed open
External X open closed
3. Recommended Seals:
90 durometer that is compatible with the hydraulic fluid.
P, A, B and T: 12 mm inside diameter by 2 mm
cross-section
X: 8 mm inside diamter by 2 mm
cross-section
4. Location of X port in valve body does not correspond to
ISO standards.
NULL FLOW ADJUSTMENT
It is often desirable to adjust the null flow of a servo valve
independently of other system parameters. The mechanical
null adjustment permits convenient control function set-
ups. Valves with mechanical null adjustment allow for at
least ±10% adjustment of null flow. Mechanical feedback
elements position the spool relative to the valve body for a
given input signal.
Mechanical Adjustment Procedure
The mechanical null adjustor is a hex socket adaptor
located behind the pan head screw in the motor cap (see
illustration below) which, when adjusted, provides control
of the spool position to obtain the desired flow null.
Normal adjustment should require less than ± one turn.
Limit null screw adjustment to less than ± two turns.
Adjustment Procedure
a. Using a blade screwdriver, remove the null access screw
to permit adjustment of the hex socket setscrew.
b. Using a 1/8 inch Allen Wrench, adjust the setscrew to
obtain the desired flow null.
Note: Clockwise rotation of the null adjuster produces flow
out port A.
c. After the desired flow null has been obtained, replace the
null access screw.
Tools and Equipment
a. Blade screwdriver
b. Allen wrench set (1/8 inch)
Optional Manual Override Operation
At times it may be convenient to activate the servo
valve manually rather than with an electrical control
signal. This can be done on the G631/631 series with the
optional manual override. With supply pressure applied,
rotating the manual override handle on the motor cap fully
counterclockwise will result in the right port pressure
increasing. Rotating the manual override handle on the
motor cap fully clockwise will result in the left port
pressure increasing.
Moog G631/631 Series Flow Control Servo Valves
BACKGROUND
11 Rev. L, January 2014
Optional Manual Override
FLOW CALCULATION
The actual flow is dependent upon electrical command
signal and valve pressure drop. The flow for a given valve
pressure drop can be calculated using the square root
function for sharp edge orifices.
Q = Q
N
Q actual flow
Q
N
rated flow
∆p actual pressure drop per spool land
∆p
N
rated pressure drop per spool land
Standard Axis Cut Open Center Spool Valves Closed Center Spool Valves
Input Current
Control Flow
Q
I
Overlap
Zone
Input Current
Control Flow
Q
I
Control Flow
Input Current
Q
I
Underlap
Zone
7.5 (2)
4 (1)
2 (0.5)
38 (10)
14
(200)
75 (20) G631-3006B
60 (15) G631-3005B
40 (10) G631-3004B
20 (5) G631-3003B
10 (2.5) G631-3002B
5 (1.3) G631-3001B
21
(300)
28
(400)
70
(1000)
140
(2000)
315
(4500)
76 (20)
114 (30)
152 (40)
190 (50)
19 (5)
15 (4)
11 (3)
∆p [bar (psi)]
Q [l/min (gpm)]
Flow Diagram
NULL CUT OPTIONS
Default, without request for
optional cuts
Normally used in hydraulic motor
applications
Normally used in failsafe
applications
∆ p
∆ p
N
Moog G631/631 Series Flow Control Servo Valves
BACKGROUND
12 Rev. L, January 2014
See Ordering Code for reference
RELATED PRODUCTS
Moog G631/631 Series Flow Control Servo Valves
BACKGROUND
13 Rev. L, January 2014
Din Rail Modules - Analog Control Cards
Moog’s DIN rail mounted module analog control cards
are ideal for use in enclosures where space is limited.
Modules include servoamplifers, transducer conditioning
electronics, command and auxiliary function modules,
valve drive amplifiers, and power supplies. All of these
modules are CE marked and require a 24V DC supply. The
modules mount to standard 35mm DIN rail mount for easy
installation and removal.
Portable Valve Testers - Evaluates Valves in the Field
Valve testers are a cost effective method for evaluating
valves in the field. They provide a quick and easy means of
differentiating between hydraulic and electronic problems.
There are five models to choose from, each with different
levels of capability and flexibility to meet your specific
requirements. All valve testers have a compact, easily
portable design.
Mounting Manifolds - Easier Installation and Maintenance
Various mounting manifolds are available for standard
industrial valves, including base and adapter types for
mounting and flushing requirements. Other hardware such
as bolts and connectors are also available.
The specific accessories you may need for a particular
model are listed in the relevant product catalogs and can
be ordered through your local office.
The most effective way to reduce life cycle costs of an
oil hydraulic system, regardless of the types of valve
used, is through close attention to contamination control.
For industrial servo systems the ideal system filter
arrangement is summarized as follows:
• Use a 10 micron (Beta 10 >= 75) high pressure filter
without by-pass just before the valve or critical parts
of the valve (e.g. pilot)
• Use a 3 micron (Beta 3 >= 75) low pressure filter in the
return or bypass line.
• Use a filter in the tank breather that is at least the
same filtration level as the finest filter in the system.
This recommendation is based on the fact that most servo
and proportional valves can accept the odd particle up to
25 microns so the pressure filter will protect the valve
from catastrophic failure. The real work is done by the low
pressure filter reducing the small particle contamination
which is the prime contributor to component wear and
silting.
Assuming that the filters are properly dimensioned and
care is taken during initial installation and maintenance,
the aim should be to limit oil contamination to 16/13
(under ISO 4406:1987) or 19/16/13 (under ISO 4406:
1999).
For long life, the maximum levels per ISO 4406: 1987
and 1999 are 14/11 and 17/14/11, respectively.
It is important to note that these are maximum
contamination levels and with proper care and regular
filter change, significantly lower levels can and should
be achieved. Attention must also be paid to a number of
other factors that contribute to oil condition problems
such as elevated temperatures, high tank humidity,
“dirty” new oil, etc.
Filtration - Oil Filtration Requirements for
Industrial Servo Systems
Din Rail Module
Valve Tester
Mounting Manifolds
Hydraulic Filters
ROUTINE MAINTENANCE GUIDELINES
Moog G631/631 Series Flow Control Servo Valves
BACKGROUND
14 Rev. L, January 2014
Every six months or 4,000 operating hours, check for
proper operation of the control valve assembly by
performing the preventative maintenance steps outlined
below. These checks do not require removal of the valve
from the process line. If a problem is suspected, repair the
valve assembly prior to returning the unit to service.
• Replace the hydraulic filter element
• Stroke the valve and check for smooth, full-stroke
operation; unsteady motion could indicate a servo
valve, actuator or process valve problem
GENERAL INFORMATION
Effects when Storing Valves
The following effects may occur when storing valves for
a long time:
• Sealing materials become brittle, possibly resulting
in leaks
• Hydraulic fluid becomes gummy, possibly resulting in
friction
Storage Time
The storage time starts at stock receipt and ends at
mounting of the valve.
Preservatives
If preservation is carried out, use only preservatives
which are compatible with the sealing materials and do
not affect the valve, spare parts and accessories.
BEFORE STORAGE
Note: If the valves are exposed to aggressive
environmental influences during storage, vacuum
packaging may be necessary. We recommend the
following preparatory measures for storage:
Mount the shipping plate on the valve.
This is the only way of adequately protecting the valves
against the ingress of dirt and moisture and protecting
the seals against the effects of ozone and UV.
Put the valve, spare parts and accessories into the
original packaging.
Package each valve separately.
Enclose anti-tarnish paper or package the valve, spare
parts and accessories with corrosion inhibiting film.
(Only for storage time > 1 year.)
Multipacks of single valves in their individual packages
are allowed.
Seal the original packaging properly.
This is the only way of adequately protecting the valves,
spare parts and accessories against damage.
STORAGE CONDITIONS
We recommend the following ambient conditions for
storage:
• Dust-free, moderately ventilated
• As vibration-free and shock-free as possible
Shock resistance (as per EN 60068-2-27):
50 g, 6 directions, half-sine 3 ms
Vibration resistance (as per EN 60068-2-6):
30 g, 3 axes, frequency 10 to 2,000 Hz
Temperature
Recommended: +15 to +25 °C (+59 to +77 °F)
Permissible: -40 to +60 °C (-40 to +140 °F)
Temperature fluctuations >10 °C (50 °F) must be
avoided.
Distance to shielded radiators: > 1 m (3 ft)
No direct exposure to sunlight
No sources of light with a high UV content
UV rays generate ozone, which damage sealing
materials.
Relative air humidity: < 65 %, non condensing
AFTER STORAGE
We recommend to check the original packaging, valve,
spare parts and accessories for possible damage or
alterations due to storage, that is, before use.
Damaged or not functional valves, spare parts and
accessories must not be started up.
Sealing materials with the following characteristics
must not be used:
• Contamination
• Cracking
• Hardening/softening
• Stickiness
• Discoloration
Storage Time > 5 Years
We recommend that the valve be checked by us or one
of our authorized service centers after a storage time
of more than 5 years.
Storage Time > 10 Years
After a storage time of more than 10 years the valves
have to be checked by us or one of our authorized
service centers.
Moog G631/631 Series Flow Control Servo Valves
BACKGROUND
15 Rev. L, January 2014
ABOUT MOOG
Moog Inc. is a worldwide designer, manufacturer and
integrator of precision control components and systems.
Moog’s Industrial Group designs and manufactures
high performance motion control solutions combining
electric, hydraulic, and hybrid technologies with expert
consultative support in a range of applications including
energy production and generation machinery, industrial
production machinery and simulation and test equipment.
We help performance-driven companies design and
develop their next-generation machines.
Moog maintains facilities in 26 countries around the globe.
This vast scope ensures that our engineers remain close
to the needs of machine builders and provide flexible
design solutions and technical expertise tailored to our
customers’ toughest challenges.
Moog experts work in close collaboration with machine
builders and application engineers to design motion
control systems for greater productivity, higher reliability,
superior connectivity, less costly maintenance and more
effective operations. Our regional presence, industry
knowledge and design flexibility ensures Moog motion
control solutions are tailored to their environment—
from meeting operating regulations and performance
standards, to taking machine performance to a higher
level.
Products
At the heart of every Moog solution is an array of products
engineered for precision, high performance and reliability.
For more than six decades, Moog products have been
specified for critical machine applications.
Some are developed specifically for unique operating
environments. Others are standard equipment on
machines across many industries. All are continuously
improved to take advantage of the latest technology
breakthroughs and advancements.
Moog products include:
• Servo Valves and Proportional Valves
• Servo Motors and Servo Drives
• Servo Controllers and Software
• Radial Piston Pumps
• Actuators
• Integrated Hydraulic Manifold Systems and Cartridge
Valves
• Slip Rings
• Motion Bases
Radial Piston Pumps
Servo Drives
Active Cartridge Valves
Servo Valves
Moog G631/631 Series Flow Control Servo Valves
BACKGROUND
16 Rev. L, January 2014
ABOUT MOOG
Hydraulic solutions
Since Bill Moog invented the first commercially viable
servo valve in 1951, Moog has set the standard
for world-class hydraulic technology. Today, Moog
products are used in a variety of applications -
providing high power, enhanced productivity and ever
better performance for some of the world’s most
demanding applications.
Electric solutions
Clean operation, low noise generation, less
maintenance and reduced power consumption
make Moog electric solutions ideal for applications
worldwide. Moog is the ideal partner for applications
where transitioning technologies requires special
expertise.
Hybrid solutions
By incorporating the advantages of existing hydraulic
and electric technologies - including modular
flexibility, increased efficiency and cleanliness -
into innovative hybrid solutions, Moog offers new
performance potential in specialized applications.
Moog Global Support
Moog Global Support is our promise to offer world-class
Repair and Maintenance Services delivered expertly by our
trained technicians. With the reliability only available from
a leading manufacturer with facilities around the world,
Moog offers you service and expertise you can count on to
keep your equipment operating as it should.
This promise offers many benefits to our customers
including:
• Reduce your downtime by keeping critical machines
running in peak performance
• Protect your investment by ensuring reliability,
versatility and long-life of products
• Better plan your maintenance activities and make
systematic upgrades
• Leverage our flexible programs to meet the unique
service requirements of your facility
Look to Moog for global support including:
• Repair services using OEM parts are performed by
trained technicians to the latest specifications
• Stock management of spare parts and products to
prevent unplanned downtime
• Flexible programs, tailored to your needs such as
upgrades, preventative maintenance and annual/
multi-year contracts
• On-site services bring the expertise to you, providing
quicker commissioning, set-up and diagnostics
• Access to reliable services that are guaranteed to
offer consistent quality anywhere in the world
For more information on Moog Global Support
visit www.moog.com/industrial/service.
Flight Simulation
Formula One Simulation Table
ACCESSORIES AND SPARE PARTS
Series Dependent Accessories and Spare Parts
Accessories G631/631 Series
Part designation Description Part number
Attachment screws 4 required M8x45 ISO 4762-10.9 (5/16-18NC by 1.75 long) tightening B64929-007B070
Metric Torque 13 Nm (11.5 lbf-in)
Attachment screws 4 required 5/16-18NC by 1.75 long tightening torque 13 Nm (11.5 lbf-in) C66391-144B
Inch
Mating connector 4 pin electrical connector B46744-004
(-49054F014S002S) [MS3106F14S-2S]
Mounting manifold Base mounting manifold B52576AM001
Flushing plate Manifold employed in place of valve when initially cleaning hydraulic fluids B67728-002
AMO manifold Adjustable metering orifice manifold used to bleed fluid between A and B B64820AM003
ports for better pressure control
Safety manifold Sandwich manifold used to lock, extend and retract cylinder upon loss B64291AMNNXXXX
of electrical signal or hydraulic pressure
Part designation Description Material Part number
Base O-ring for P, T, A 5 required for P, T, A, and B ports 12 mm Fluorocarbon FKM 85 shore A25163-012-020
and B ports (0.472 in) inside diameter x 2.0 mm (0.079 in) (G2141-012-020)
cross section.
X port O-ring 1 required 8.0 mm (0.315 in) x 2.0 mm (0.079 in) A25163-008-020
cross section. (G2141-008-020)
Replaceable filter, 100 µm nominal A67999-100
Filter replacement kit Contains the following: Fluorocarbon FKM 85 shore B52555RK200K001
2 pieces O-ring 13 mm (0.512 in) inside diameter
x 1.5 mm (0.059 in) cross section
1 piece filter disc 100 µm
Spare Parts G631/631 Series
Part designation Description Remark Part number
Catalog G631/631 series general information Note: Visit CDL 6641
www.moog.com/industrial/literature
to download document
Service manual G631/631 standard series Note: Visit CDS 6672
www.moog.com/industrial/literature
to download document
Service manual G631/631 intrinsically safe (K) series Note: Visit CDS 6750
www.moog.com/industrial/literature
to download document
Documents (not included in scope of delivery)
Moog G631/631 Series Flow Control Servo Valves
ORDERING INFORMATION
17
Rev. L, January 2014
ORDERING CODE
Moog G631/631 Series Flow Control Servo Valves
ORDERING INFORMATION
18 Rev. L, January 2014
05
10
10
O
D
10
Q
R
8
V
Fluorocarbon (FKM) 85 Shore A
G631/631
-
--
7
5
6
M
5
9
B
12345678910
5.0
20
20
J
F
4
3
1
2
315
4
Model Number Type Designation Rated Flow (∆1,000 psi) Internal Leakage (at 3,000 psi) Rated Current (single coil)*
lpm gpm lpm gpm mA
G361-3001B H05JOFM4VBR 5 1.3 < 0.52 < 2.0 100
G631-3002B H10JOFM4VBR 10 2.5 < 0.60 < 2.3 100
G631-3003B H20JOFM4VBR 19 5.0 < 0.70 < 2.6 100
G631-3004B H40JOFM4VBR 40 10.0 < 0.78 < 3.0 100
G631-3005B H60JOFM4VBR 60 15.0 < 0.86 < 3.2 100
G631-3006B H75JOFM4VBR 75 20.0 < 0.96 < 3.6 100
*Overdrive more than 10% current is NOT recommended.
Model designation
Factory Identification (Revision Level)
Valve version
Rated flow in l/min (gpm)
Maximum operating pressure in bar (psi) and body material
Bushing/spool design
4-way/±10 % overlap/linear
4-way/axis cut/linear
(4,500) aluminum
± 15 mA series
± 50 mA series
Signals for 100 % spool stroke
Seal material
Internal
Exernal
Pilot connections
Low flow, nozzle-flapper
Pilot stage design
Spool position without electrical signal
Mid position
For = 35 bar (500 psi) per spool land p
Valve connector
Model number (assigned at the factory) Type designation
(2.5)
(1.3)
(5.0)
N
Optional feature
Connector over B-side
H
High response
Series specification
40
40 (10)
60
60 (15)
Assigned at the factory
Preferred Models
75
75 (20)
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G631/631 Series Flow Control Servo Valves
TJW/PDF, Rev.L, January 2014, Id. CDL6641-en
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