MBP MBB MBW YUKEN Hydraulic Modular Relief Valve 01 03 NG6 NG10

Product Overview

This series covers MBP / MBA / MBB / MBW relief modular valves, fully interchangeable with the YUKEN equivalents — the standard pressure-control building blocks of stacked hydraulic manifolds. Mounted between the solenoid directional valve and the base plate with no piping, they provide pressure limiting and overload protection for the pump source or individual actuator branches:

• MBP — relief on the P line (pump / system pressure protection)
• MBA — relief on the A line (A-port branch overload protection)
• MBB — relief on the B line (B-port branch overload protection)
• MBW — relief on both A and B lines (dual-branch overload protection)

Engineered as a direct drop-in interchange: mounting surface, port identification, body thickness and stacking order match the original, so the valve replaces the OEM unit without modifying the manifold, bolts or circuitry. Every unit is 100% simulated working-condition tested before shipment, with actuation performance verified at set pressure and flow.

Technical Specifications

Series common data:

• Mounting surface: 01 size = ISO 4401-AB-03-4-A (NG6 / D03 / CETOP-3 / NFPA-D01); 03 size = ISO 4401-05-03-0-05 (NG10 / D05 / CETOP-5 / NFPA-D02)
• Mounting: stack-type (sandwich), stud-bolt mounting on base plate, no piping; up to 1–5 stacks (incl. directional valve)
• Fluids: mineral hydraulic oil (ISO VG 32 / VG 46), phosphate ester / polyol ester (F- special seals required), water-glycol
• Recommended viscosity: 15–400 mm²/s; operating temperature: -15°C to +70°C
• Displacement: N/A — valves are rated by max flow, not displacement
• Max speed: N/A — static-mount component, no rotating elements

MBP-01-H-30 (P-line relief, 01 size, design 30):

• Max operating pressure: 21 MPa (210 kgf/cm²)
• Max flow: 35 L/min
• Pressure adjustment range (H): 7–21 MPa
• Control: direct-acting relief (mechanical adjusting screw + lock nut)
• Mass: 1.1 kg
• Seal kit: KS-MBP-01-30

MBA-01-H-30 (A-line relief, 01 size, design 30):

• Max operating pressure: 21 MPa; max flow: 35 L/min
• Pressure adjustment range (H): 7–21 MPa
• Control: direct-acting relief; mass: 1.1 kg

MBB-01-H-30 (B-line relief, 01 size, design 30):

• Max operating pressure: 21 MPa; max flow: 35 L/min
• Pressure adjustment range (H): 7–21 MPa
• Control: direct-acting relief; mass: 1.1 kg

MBP-03-B-30 (P-line relief, 03 size, design 30):

• Max operating pressure: 31.5 MPa (4570 PSI)
• Max flow: 70 L/min (18.5 US GPM)
• Pressure adjustment range (B): ★~7 MPa (★ = minimum adjustment pressure per characteristic curve + tank back pressure; market equivalents typically spec ≈0.8–7 MPa)
• Control: direct-acting relief; mass: 3.1 kg
• Seal kit: KS-MBP-03-30

MBW-01-B-10T (A&B dual-line relief, 01 size, manufacturer-compatible code):

• Note: this code is a manufacturer-compatible designation (YUKEN’s official 01-series catalog lists MBP/MBA/MBB only; the official A&B dual-relief type is MBW-03-*-30 in the 03 series). Function: relief on both A and B lines.
• Parameter basis: per the 01-series relief family — max operating pressure 21 MPa class, max flow 35 L/min class, B adjustment range ★~7 MPa class, mass ≈1.1 kg class; manufacturer-published figures, confirm against the nameplate / factory test certificate
• Peak pressure: N/A — valves are rated by max operating pressure

Key Technical Advantages

1. True drop-in interchangeability: identical mounting surface, port layout, body thickness and stacking sequence to the YUKEN original — replace the OEM valve directly with no manifold rework or extended downtime.
2. Precision direct-acting design: poppet/spool with a precision adjusting spring gives immediate, stable response; the locking nut holds the set point against vibration.
3. 100% simulated working-condition testing: each unit is individually validated under load-simulating pressure cycles before shipping.
4. Piping-free stacking: eliminates tube fittings, leak paths, vibration and noise at the source — the documented design benefit of this modular valve class.
5. High pressure margin, wide flow coverage: 21 MPa / 35 L/min (01) and 31.5 MPa / 70 L/min (03) cover machine-tool auxiliary circuits through medium/high-pressure main circuits.
6. Broad fluid and temperature compatibility: mineral oil, phosphate ester (F- seals) and water-glycol; 15–400 mm²/s, -15°C to +70°C.

Application Areas

• Injection molding machines: clamping/injection pressure limiting and system overload protection
• Machine tools and special-purpose machines: hydraulic clamping, feed and lubrication pressure control
• Hydraulic presses and die-casting machines: main-circuit pressure setting, branch overload protection
• Hydraulic power units (HPUs): pump outlet pressure limiting, accumulator circuit protection
• Metallurgy and automated production lines: independent A/B-port branch pressure limiting
• Auxiliary circuits of mobile machinery where industrial-grade stacked valves are specified

Expert Maintenance Tips

• Adjustment: loosen the lock nut, turn the adjusting screw clockwise to raise pressure, and re-tighten the lock nut firmly after setting (official operating instruction).
• Minimum adjustment pressure: minimum set point = minimum-adjustment characteristic value + tank-line back pressure (including the T-line pressure drop of all stacked valves below); allow margin when the tank back pressure is high.
• Low-flow stability: at small flows the set pressure may become unstable — operate within the allowable range of the minimum-flow characteristic curve.
• Stacking order: follow the prescribed stacking sequence when combining with reducing and pilot-operated check valves to prevent internal-leakage-induced actuator creep; do not exceed 5 stacks (incl. directional valve).
• Seals: keep mounting faces clean and burr-free; renew seal kits (KS-MBP-01-30 for 01 series; KS-MBP-03-30 / KS-MBW-03-30 for 03 series); use the F- special-seal version for phosphate ester fluids.
• Fluid maintenance: keep oil cleanliness and viscosity within the recommended band (15–400 mm²/s) and sample regularly to prevent contamination from affecting adjustment accuracy.