Pressure Control Valve

with integrated Electronics

Cetop 3 · Series D 635

MOOG DDV PCV features the following advantages:

r Direct drive with high force level permanent magnet

linear motor for high reliability

r No pilot stage oil flow

r Low hysteresis, high resolution, excellent linearity

r Pressure independent dynamic performance of servo

valve

r Pressure control in mainstream and bypass function

General

The series D635 is a direct driven pressure control valve (PCV)

of size NG 6 (Cetop 3). The PCV consists of a DDV servovalve,

pressure control electronics, pressure sensor and ramp circuit

for the pressure command signal. All elements are integrated

in a compact unit. This provides the control of the PCV direct

from the machine control without interface electronics.

r Standardised, accurate pressure feedback signal for

monitoring

r 2 x 2 way operation extends the flow capacity in bypass

mode

r At loss of supply voltage, the valve returns to its spring

centered safe position and connects ports A with T or

P with A.

r Improved false polarity protection and over voltage

protection

r IP 65 (DIN 40050) degree of protection

Our quality management

system is certified in accor-

dance with DIN EN ISO 9001.

given, the user has to check

the suitability of the products

described here.

In case of doubt please con-

tact MOOG.

This catalogue is for users with

technical knowledge.

To ensure that all necessary

characteristics for function

and safety of the system are

Series D635

Operation

Pressure Control function

The actual pressure in port A

is measured by a pressure

transducer and the output

signal is conditioned and

compared with the pressure

command signal. If there is

an error between pressure

command signal and actual

pressure value, the pressure

controller changes current to

the linear motor in such a way

that the error becomes zero.

The pressure command signal

can be directed via a ramp

circuit with 20 s ramp up /

ramp down time or direct to

the comparison point (see

block diagram page 3).

Valve Flow function

The valve flow function is a

sub function within the

pressure control valve and not

controllable externally. With

zero current through the li-

Q [l/min] = calculated flow per land at Dp

[l/min] = rated flow per land at Dp

Dp [bar] = actual valve pressure drop per land

[bar] = rated valve pressure drop per land

Q=Q

∆

Valve Flow and Pressure Drop

At maximum valve opening, the valve flow at rated valve

pressure drop, Dp

= 5 bar per metering land, is rated flow, Q

per land. For other than rated pressure drop, the valve flow

changes at constant valve opening according to the following

function for a sharp edged orifice (metering land).

The valve flow Q calculated in this way should result in an

average flow velocity in ports P, A, B or T of no more than 30

m/s.

near motor, the output force

is zero and the centering

spring moves the spool to its

neutral position, where port

A is connected to port T, and

port P to B. Port B is normally

blanked off. This position is

defined as fail safe, (e.g. at

loss of supply voltage).

As the motor current in-

creases, the flow paths A ç T

and P ç B start to close and

eventually are fully closed. For

the 2 x 2 way version (valve in

bypass) this is the case at 90

% and for the 3 - way version

at approx. 50 % of total spool

stroke (see flow functions

page 4).

Further increasing of the

current through the linear

motor in the 3-way version

causes the flow paths to open

again to their max. opening

for max. valve flow Q (Q

Principle of

Permanent magnet linear

motor operation

The linear motor is a perma-

nent magnet excited diffe-

rential motor. The permanent

magnets provide a part of the

required magnet force. For a

linear motor, the current

needed is considerably lower

than would be required for a

comparable proportional so-

lenoid.

The spool driving linear motor

has a neutral position at zero

coil current given by the

centering spring. The spool

driving force is proportional

to coil current and moving

the spool against the cen-

tering spring. The linear motor

needs no current in the spring

centered (neutral) position.

The high spool driving force

ensures a reliable spool

movement against flow and

friction forces. This makes the

valve very insensitive to

contamination.

Kabel-

bohrung

Permanent

magnets

Centering

springs

Bearing

Coil Armature Verschlussschraube

Series D635

Block Diagram / Symbols

Sectional View

Block Diagram

Hydraulic Symbols

2 x 2 - Way - Function

3 - Way - Function

Sectional View

Example :

By-pass flow characteristic

(standard) with Q

= 36 l/min per

land

Double flow: 2 x Q

= 72 l/min

Series D635

Typical Characteristic Curves

Flow Function

at Dp

= 35 bar per land

3 - Way function

Pressure control function

Pressure in port A

Application note

The pressure controller needs

to be adapted to the load to

optimise dynamic perfor-

mance.

The load is mainly influenced

by:

valve rated flow Q

, actual

valve pressure drop per land

Dp, fluid volume to be con-

trolled connected to port A,

mechanical load stiffness etc.

Contact our application engi-

neers for assistance.

Example :

Symmetric flow characteristic

with Q

= 20 l/min

2 x 2 - Way function

Valve design Spool type, single stage with bushing

Actuation Direct with permanent magnet linear motor

Mounting pattern DIN 24340 / ISO 4401 / Cetop Form A6 / Cetop 3 with or without leakage port Y ²

)

Port diameter P, A, B, T 7,9 mm

Pilot supply none

Mounting direction any (air vent of valve must be possible)

Seal material NBR, FPM

Degree of protection DIN 40050, with mating connector IP 65

Mass 2,5 kg

Rated flow Q

2,5 / 5 / 10 / 20 / 40 (at 3-way function)

at Dp

= 35 bar per land, tolerance ± 10 % 4,5 / 9 / 18 / 36 (at 2-way function)

2 x 36 (at 2 x 2 way function)

Null leakage flow Q

0,15 / 0,3 / 0,6 / 1,2 l/min

max. Operating pressure p

max

, static

ports P, A, B 350 bar

port T without Y 50 bar

port T with Y 350 bar

port Y direct to tank

Mating connector standard (DIN 43563) 6 + PE

Supply voltage for integrated electronics U

nom

+ 24 V DC

Tolerance range U

min

+ 19 V DC

max

+ 32 V DC

Current consumption at U

nom

= + 24 V DC

min

at pressure command zero 0,150 A

(linearmotor without current)

max

1 A

Pressure command signals 0 to 10 V, 0 to 10 mA, 4 to 20 mA

Actual pressure signal + 4 to + 20 mA

Ramp up time = Ramp down time 20 s

Relative duty cycle 100 % ED

External fuse per valve 1,6 A T (slow blow)

Threshold

< 0,1 %

Hysteresis

< 0,2 %

Nullshift at DT = 55 K < 1,5 %

Linearity < 0,5 %

Operating fluid DIN 51524 Mineral oil based hydraulic fluid, others on request

Fluid temperatur range – 20 ... + 80 ° C

Viscosity recommended 15 ... 45 mm²/s

allowable 5 ... 400 mm²/s

Filter rating recommended ß

³ 75 x £ 6 (6 µm absolute)

allowable ß

³ 75 x £ 10 (10 µm absolute)

Class of cleanliness according to NAS 1638 at least 6

ISO 4406 at least 15 / 11

System filter High pressure filter, mounted in the main flow

without bypass, but with contamination indicator

1) measured at p

= 140 bar pressure and viscosity of n = 32 mm

2) leakage port Y must be used at p

> 50 bar

3) for long life wear protection of metering lands

Series D635

Technical Data

Series D635

Connector wiring

Dimensions

Notes:

Supply voltage U

nom

= + 24 VDC.

Current consumption I

max

= 1 A

Power supply according to VDE 0551

All signal lines (also those of external transducers) are shielded.

Shielding connected radially to ^ (0V) on power supply

+ 24 VDC ( 19 to 32 VDC )

^ ( 0 V )

0 to + 10 mA

load resistance 200 W

+ 4 to + 20 mA

load resistance 200 W

Current command

0 to ± 10 mA

Current command

+ 4 to + 20 mA

load resistance 300 to 500 W, with respect to ^ ( 0 V )

Voltage command

0 to ± 10 VDC

0 to + 10 VDC

Input resistance 10 kW

Supply

Supply / Signal ground

Not used

Pressure command

signal

Pressure inverted

command signal

Connector wiring

Protectiv grounding

Function

Valve

Connector

Mating

connector

Machine side

0 to – 10 VDC

Input resistance 10 kW

0 to – 10 mA

load resistance 200 W

Actual pressure value

Not used

Valve with 6+PE pole connector to DIN 43563 and mating connector (metal shell) with leading protective grounding connection ( ).

Thread 7/8-20 UNF 2A.

Dimensions

Valve connector

S 6 + PE-pole DIN 43563

Seal material

N NBR (Buna N) Standard version

V FPM (Viton) Special version

others on request

Y - Port

0 Closed with plug p

Tmax

= 50 bar

1 Open, with filter insert p

> 50 bar

Bushing / spool type

B 3 way: P ç A, A ç T: ~ Axis cut, linear characteristic

Z 2 x 2 way: P ç B, A ç T: 10 % overlap, linear characteristic (only bypass)

X Special version on request

Pressure ranges

Rated pressure max. operating pressure

C 100 100

F 210 250

J 315 400

K 350 400

X Special range on request

Rated flow

(l/min) at Dp

per land

5 bar 35 bar

01 1 2,5

02 25

04 410

08 820

16 16 40

Valve version

P Proportional valve

Series D635

Ordering information

All combinations may not be available. Options may increase price.

Technical changes are reserved.

Valve type

Pressure control without ramp

B Valve in by-pass

M Valve in main stream

Pressure control with ramp

P Valve in by-pass

R Valve in main stream

llll lllllllllllll

Specification status

– Series-

Specification

E Preseries-

Specification

Z Special-

Specification

Model designation

assigned at the factory

Linear motor

1 Standard

Factory identification

D635

Spool position without electrical supply

A defined end position A ç T connected

B defined end position P ç A connected

Signals for pressure control

Command Output

M 0 to 10 V +4 to +20 mA

P 0 to 10 mA +4 to +20 mA

S +4 to +20 mA +4 to +20 mA

Electrical supply

2 + 24 VDC (19 to 32 VDC)

D 635 E / Rev. 3 / 08.99

MOOG Controls Limited

Ashchurch

Tewkesbury

Gloucestershire

GL20 8NA

Telephone (0684) 29 66 00

Telefax (0684) 29 67 60

Australia Melourne

Austria Vienna

Brazil São Paulo

Denmark Birkerød

England Tewkesbury

Finland Espoo

France Rungis

Germany Böblingen

Hong Kong Kwai Chung

India Bangalore

Ireland Ringaskiddy

Italy Malnate(VA)

Japan Hiratsuka

Korea Kwangju

Philippines Baguio

Russia Pavlovo

Singapore Singapore

Spain Orio

Sweden Gothenburg

USA East Aurora (NY)

This catalougue is for users

with some basic technical

knowledge. To ensure that

all necessary characteristics

for function and safety of the

system are con-sidered, the

user is cautioned to check the

suitability of the products.

If there are questions or con-

cerns, please contact MOOG.

MOOG GmbH

Hanns-Klemm-Straße 28

D - 71034 Böblingen

Postfach 1670

D - 71006 Böblingen

Telefon (07031) 622-0

Telefax (07031) 622-191