Parker Hydraulic Group
VO40 Open-Center Directional Control Valve

The VO40 is an open-center directional control valve with the flexibility of sectional construction.  Spools have metering notches in the three critical areas – open-center, parallel path and tank, which optimizes simultaneous metering.

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  • Enhanced metering – especially during simultaneous operation, this is accomplished by having notches in the three critical areas of the spool: open center, parallel path and tank.
  • Improved simultaneous metering – having a transition check in each work section ensures that a load does not “dip” downward when metering two or more work-sections.
  • Repeatability – consistent metering from valve to valve is achieved by flycutting all of the critical cast lands. This means that the notch position relative to the spool stroke is controlled and predictable. The result is consistent machine control.
  • Reduced operator fatigue – the open-center core is a split wing or “Y” core design, which provides for a consistent lever force when selecting the spool from neutral to both power positions.
  • Reduced function drift – low internal leakage accomplished thru the use of contemporary honing technology. Also, for those functions requiring near zero drift, pilot-operated checks are available.
  • Small footprint – port accessories are installed vertical to the spool, allowing the handle to be positioned closer to the valve body.
  • Ease of service – the bottom two stud assemblies are slotted, enabling a work section to be replaced without completely disassembling the valve assembly. This is accomplished by loosening the top tie bolt and then liftingthe section out of the assembly. Downtime is minimized.
  • Easy conversion from a left-handed to a right-handed section – the work section housing and spool are symmetrical, which enables the spool to be inserted in either end of the housing.
  • Improved spool seal life – the enclosed handle assembly protects the spool and spool seal area from contamination and the potential corrosion.

Pressures:

  • Inlet Port: 300 Bar (4350 PSI)
  • Tank Port: 50 Bar (725 PSI)
  • Work Ports: 300 Bar (4350 PSI)

Flow Rates (maximum recommended): 40 LPM (10.6 GPM)

Internal Pilot Pressure: Required for solenoids – consult factory

Spool Leakage from work port to tank:

  • Max. 6 mL/min @172 Bar (2500 PSI)
  • Oil temp. 50ºC (122ºF), and viscosity 40 cSt