D636 Direct-Operated Servo Valves with Fieldbus Interface

ISO 4401 SIZE 03


  • Directly driven by linear force motor with no pilot flow required
  • Linear force motor with high force range offering no flow limitations
  • Directly driven design means pressure-independent dynamic performance
  • Low current consumption at and near hydraulic null
  • Integrated digital electronics allows a high grade of flexibility with fieldbus interface

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Flow Information

  • Flow Calculation
  • Flow Diagram

The actual valve flow is dependent on the spool and the pressure drop Δp across spool lands.

At 100% command signal the valve flow at rated pressure drop ΔpN = 35 bar (500 psi) per metering land is rated flow QN.  For other than rated pressure drop, the valve vlow changes at constant signal according to the following formula:

Q = QN√(Δp/Δpn)

Q = actual flow [l/min (gpm)]
QN = rated flow [l/min (gpm)]
Δp = actual valve pressure drop [bar (psi)]
ΔpN = rated valve pressure drop [bar (psi)]

The actual flow Q must not exceed a mean flow velocity of 30 m/s (96.54 ft/s) at ports P, A, and T.

Design Data

Design Single-stage spool valve with bushing
Actuation Directly with permanent magnet linear force motor
Valve configuration 2-way, 3-way, 4-way and 2x2-way operation
Mounting pattern ISO 4401-03-03-0-05 (with or without leakage port Y)
Diameter of ports 7.9 mm (0.31 in)
Installation position As desired
Mass 2.5 kg (5.5 lb)
Storage temperature range -40 °C to +80 °C (-40 °F to +176 °F)
Ambient temperature range -20 °C to +60 °C (-4 °F to +140 °F)
Vibration resistance 30 g, 3 axes, 10 Hz to 2 kHz (as per EN 60068-2-6)
Shock resistance 50 g, 6 directions, half-sine 3 ms (as per EN 60068-2-27)

Hydraulic Data

Measured at 140 bar (2,000 psi), fluid viscosity 32 mm2/s (cSt) and fluid temperature 40°C (104°F)

Maximum operating pressure range, port P, A, B 350 bar (5,000 psi)
Maximum operating pressure range, port T without Y 50 bar (725 psi)
Maximum oprtating pressure range, port T with Y 350 bar (5,000 psi)
Maximum operating pressure range, port Y Depressurized to tank
Maximum flow 75 l/min (19.8 gpm)
Rated Flow (model dependent) at Δp rated 35 bar (500 psi)/land 5 / 10 / 20 / 40 l/min (1.3 / 2.6 /5.3 / 10.6 gpm)
Leakage flow at zero lap (model dependent) 0.15 / 0.3 / 0.6 / 1.2 l/min (0.04 / 0.08 / 0.16 0.32 gpm)
Hydraulic fluid Per DIN 51524 Parts 1 and 3 and ISO 11158
(Other fluids upon request)
Seal material HNBR, FKM, others upon request
Temperature range of hydraulic fluid -20°C to 80°C (-4°F to 176°F)
Viscosity range, recommended 15 mm2/s (cSt) to 100mm2/s (cSt)
Viscosity range, maximum permissible 5 mm2/s (cSt) to 400 mm2/s (cSt)
Recommended cleanliness class for functional safety as per ISO 4406*

< 18 / 15 / 12

Recommended cleanliness class for endurance (wear) as per ISO 4406* < 17 / 14 / 11

The cleanliness of the hydraulic fluid has a great effect on functional safety (reliable spool positioning, high resolution) and wear of the spool lands (pressure gain, leakage losses)

Static and Dynamic Data

Step response time for 0 to 100% stroke 8 ms
Hysterisis < 0.05 % (typical) 0.10 % (maximum)
Null shift at ΔT = 55 K < 1.5%
Manufacturing tolerance with respect to Q_rated <3%

Electrical Data

Duty Factor 100%
Degree of protection as per EN 60529 IP 65 with mounted mating connectors or with mounted dust protection caps with sealing function.
Supply voltage 18 V DC to 32 V DC
Maximum power consumption

1.7 A

Fuse protection, external per valve 2 A (slow blowing)
Power consumption of motor in neutral position 9.6 W (0.4 A 24 V DC)
Maximum power consumption 28.8 W (1.2 A at 24 V DC)
EM Compatability

Emittered interference as per EN 61000-6-4:2005.
(CANopen and Pofibus-DP)
Emitted interference as per EN 6-3:2005.
Immunity to interference as per EN 61000-6-2: 2005
(evalaution crtierion A)

Connector Type See Page 8 in catalog
Triggered electronics Intergrated in the valve; see electronics section in catalog

Characteristic Curves (typical)

  • Step Response
  • Frequency Response
  • Pressure Signal Curve
  • Flow Signal Curve
At operating pressure pp = 140 bar (2,000 psi), fluid viscosity ν = 32 mm2/s (cSt) and a fluid temperature of 40° C (104 °F)

Installation Drawings

User Manuals and Software

  • EtherCAT
  • CANopen
  • Software


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