Technical & Hydraulic Specifications
- Valve Stage Structure: Two-Stage Direct Drive DDV architecture, no flapper-nozzle pilot stage
- ISO Mounting Standard: ISO 4401 Size 05 manifold mounting pattern
- Maximum Operating Supply Pressure: 350 bar (5000 psi)
- Rated Flow @ 70 Bar Pressure Drop: 140 L/min
- Control Input Signal: ±10 VDC differential analog command signal
- Spool Position Feedback: Integrated LVDT linear variable differential transformer closed-loop spool position sensor
- Hysteresis Index: ≤0.8% full stroke
- Flow Linearity Deviation: ≤3% rated flow range
- Null Drift Temperature Coefficient: ±1.2% per 40 °C temperature variation
- 90° Phase Lag Frequency Response: 75 Hz at 25% rated spool stroke
- Permitted Hydraulic Fluid Viscosity Range: 60–450 SUS at 38 °C
- Fluid Cleanliness Requirement: ISO 4406 Code 16/13 maximum particulate contamination, recommended 14/11
- Operating Temperature Range: -40 °C to +120 °C fluid temperature; -30 °C to +85 °C ambient valve housing temperature
Functional Features
- Direct linear force motor spool actuation removes fragile flapper-nozzle pilot components prone to particle clogging
- Built-in high-precision LVDT spool position closed-loop feedback eliminates open-loop spool drift
- Integrated on-board signal conditioning electronics for LVDT signal amplification and command signal comparison
- Zero mechanical deadband zero-lapped spool machining for micro-displacement control resolution
- Built-in fluid bypass pressure compensation circuit maintaining consistent flow gain under variable supply pressure
- Over-temperature internal thermal protection circuit cutting drive current to prevent force motor burnout
Working Principle
±10 VDC external motion controller command signal inputs to valve integrated electronics, compared against LVDT real-time spool position feedback signal to generate differential drive current for linear force motor. Force motor directly pushes main control spool without intermediate pilot fluid stage; LVDT continuously measures spool travel distance to form inner spool position closed loop. Spool displacement modulates hydraulic fluid flow between supply port P, actuator ports A/B and return port T; flow volume proportionally matches input analog command signal magnitude. Integrated electronics compensate supply pressure fluctuation and fluid viscosity variation to stabilize flow gain performance.
Material Composition
- Valve Main Body: High-strength forged carbon steel, hard chrome plated internal flow passages for wear resistance
- Control Spool: Precision ground martensitic stainless steel with nitride surface hardening treatment
- Linear Force Motor Core: High-grade silicon electrical steel lamination stack, rare-earth permanent magnet rotor assembly
- LVDT Sensor Housing: Sealed stainless steel tube with PTFE fluid isolation sleeve
- Sealing Components: Fluorosilicone FKM high-temperature hydraulic oil resistant O-rings
- Onboard Electronic Enclosure: Die-cast aluminum alloy sealed housing with IP67 environmental protection
Structural Characteristics
- Standard ISO 4401 Size 05 four-port manifold bottom mounting interface
- Side-mounted sealed electrical connector with integrated shield grounding terminal for analog command wiring
- Axial integrated LVDT sensor coaxial with main spool for compact single-body integration
- External fluid drain port for pilot leakage fluid recovery (zero pilot flow DDV design with minimal leakage volume)
- Ribbed aluminum electronic housing for passive heat dissipation of drive circuit
Advantage Highlights
- Pilot-stage-free DDV design reduces valve blockage failure rate by over 80% under moderate fluid contamination
- Superior low hysteresis and linearity delivering micron-level positioning repeatability
- Wide fluid temperature and supply pressure operating range adaptable to variable industrial hydraulic conditions
- Integrated LVDT inner closed-loop eliminates external spool position feedback hardware requirement
- Hard chrome plated internal flow passages extend service life under abrasive hydraulic fluid media
- IP67 sealed electronic housing resistant to workshop oil mist, water splash and metal dust ingress
Applicable Industries
Automotive hydroforming presses, aerospace component test hydraulic rigs, precision CNC hydraulic machine tools, wind turbine pitch hydraulic control systems, steel mill strip tension hydraulic control
Installation Requirements
- Mount on flat precision machined ISO 4401 Size 05 steel manifold surface with torque calibrated mounting bolts (torque value 42 N·m)
- Hydraulic manifold internal filtration installed upstream of valve inlet port with nominal filtration rating 3 μm absolute
- Analog control signal wiring use double-shielded twisted pair cable, shield grounded only at controller cabinet end
- Install fluid temperature sensor upstream of valve supply port to monitor hydraulic oil operating temperature
Usage Precautions
- Forbid operation with hydraulic fluid cleanliness exceeding ISO 4406 16/13 particulate code; install bypass offline filtration unit for contaminated fluid systems
- Do not exceed maximum 350 bar supply pressure to avoid permanent spool body deformation
- Conduct annual LVDT zero offset calibration per factory maintenance procedure
- Replace all FKM sealing components every 3000 operating hours to prevent high-temperature oil leakage
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