PVD-15B-32BP-9AG5-4634G Nachi PVD-15B Piston Pump 19cc 24.5MPa

Product Overview

The PVD-15B-32BP-9AG5-4634G and PVD-15B-37P-9AG5-5599B are core models in NACHI (NACHI-FUJIKOSHI) PVD series dual split-flow variable displacement axial piston pumps, specifically developed for 1 to 6-ton class mini excavators and compact construction machinery. The series features a coaxial dual-circuit equal-flow output design with flow deviation between the two ports of ≤1%, ensuring straight-line travel accuracy. The PVD-15B offers a single pump theoretical displacement of 19 cm³/rev, total theoretical displacement of 38 cm³/rev, rated continuous working pressure of 21 MPa, maximum intermittent peak pressure of 24.5 MPa (3,553 psi), maximum permissible speed of 2,600 rpm, rated working speed of 2,400 rpm, suitable for ≤4.0-ton class excavators, with a base pump body reference weight of approximately 38 kg.

The PVD-15B-32BP-9AG5-4634G is fitted to Takeuchi TB135 and similar mini excavators, while the PVD-15B-37P-9AG5-5599B is compatible with Kubota U30-6, U35, and similar models. Both models feature flange-type mounting (B type), P for standard configuration, 9AG5 as the control and interface specification code, and 4634G/5599B as design numbers and customization suffixes for different OEM adaptations.

Manufactured to NACHI original engineering specifications, these pumps achieve 100% drop-in interchangeability — mounting flange, shaft dimensions, port locations, and control interfaces are dimensionally identical to the OEM unit. No piping modifications or mounting alterations are required for direct replacement. Every unit undergoes 100% simulated load testing prior to shipment, including rated pressure loading, flow-pressure characteristic verification, and thermal rise testing.

Technical Specifications 

PVD-15B-32BP-9AG5-4634G

• Model: PVD-15B-32BP-9AG5-4634G

• Series: PVD Series (NACHI / NACHI-FUJIKOSHI)

• Pump Type: Dual split-flow variable displacement axial piston pump, open circuit

• Single Pump Displacement: 19 cm³/rev

• Total Displacement: 38 cm³/rev (dual equal-flow output)

• Rated Continuous Pressure: 21 MPa (3,046 psi)

• Max Intermittent Peak Pressure: 24.5 MPa (3,553 psi)

• Max Permissible Speed: 2,600 rpm

• Rated Working Speed: 2,400 rpm

• Control Type: Constant horsepower control (standard), power shift control (optional)

• Mounting: B — Flange mounting

• Rotation: Clockwise (viewed from shaft end)

• Drain Design: Internal drain, no external case drain line required

• Excavator Class: ≤4.0 t

• OEM Compatibility: Takeuchi TB135, etc.

• Base Pump Weight: Approx. 38 kg

• Housing Material: High-strength cast iron

• Friction Pair Material: High-precision ground steel and bronze

• Recommended Fluid: ISO VG32 / VG46 anti-wear hydraulic oil

• Fluid Cleanliness: ISO 4406 18/16/13 or higher

• Operating Temperature: 10 to 60°C

PVD-15B-37P-9AG5-5599B

• Model: PVD-15B-37P-9AG5-5599B

• Series: PVD Series (NACHI / NACHI-FUJIKOSHI)

• Pump Type: Dual split-flow variable displacement axial piston pump, open circuit

• Single Pump Displacement: 19 cm³/rev

• Total Displacement: 38 cm³/rev (dual equal-flow output)

• Rated Continuous Pressure: 21 MPa (3,046 psi)

• Max Intermittent Peak Pressure: 24.5 MPa (3,553 psi)

• Max Permissible Speed: 2,600 rpm

• Rated Working Speed: 2,400 rpm

• Control Type: Constant horsepower control (standard), power shift control (optional)

• Mounting: P — Flange mounting, standard configuration

• Rotation: Clockwise (viewed from shaft end)

• Drain Design: Internal drain, no external case drain line required

• Excavator Class: ≤4.0 t

• OEM Compatibility: Kubota U30-6, U35, etc.

• Base Pump Weight: Approx. 38 kg

• Housing Material: High-strength cast iron

• Friction Pair Material: High-precision ground steel and bronze

• Recommended Fluid: ISO VG32 / VG46 anti-wear hydraulic oil

• Fluid Cleanliness: ISO 4406 18/16/13 or higher

• Operating Temperature: 10 to 60°C

PVD Series Key Characteristics

• Displacement Range: 8 to 33 cm³/rev per pump, 16 to 66 cm³/rev total (dual)

• Rated Pressure: 21 MPa (3,046 psi) across the series

• Peak Pressure: 24.5 MPa (3,553 psi) across the series

• Max Speed: 2,400 to 2,800 rpm (depending on size)

• Control Type: Constant horsepower control (standard), power shift control (optional)

• Optional Integration: High-pressure auxiliary gear pump, pilot control gear pump, control valve block

• Design Features: Extremely short overall length for compact engine compartments; internal drain eliminating drain piping

• Flow Deviation: ≤1% between the two output ports

• Target Machines: 1 to 6-ton mini excavators and compact construction equipment

Key Technical Advantages

1. 100% Drop-in Interchangeability

The PVD-15B-32BP-9AG5-4634G and PVD-15B-37P-9AG5-5599B feature flange-type mounting, with shaft dimensions, port locations, and control interfaces machined to NACHI original drawings, achieving complete physical and hydraulic interchangeability with the OEM pump. Products are completely interchangeable with originals, compatible with OEM repair kits. No piping modifications, coupling changes, or baseplate alterations are required for direct replacement, minimizing downtime and reducing total maintenance costs.

2. Dual Equal-Flow Design & Straight-Line Travel Accuracy

The PVD series’ core design advantage lies in its coaxial dual-circuit equal-flow architecture. NACHI was one of the first manufacturers worldwide to design axial piston pumps with ten pistons, enabling the total flow to be precisely divided into two exactly equal volumes. With flow deviation of ≤1% between the two ports, this ensures mini excavators maintain precise straight-line travel trajectories, avoiding steering drift caused by uneven flow distribution.

3. Constant Horsepower Control & Maximum Engine Power Utilization

The PVD-15B series features constant horsepower control as standard, continuously monitoring delivery pressure and pump displacement to limit pump input power below the engine power curve, preventing engine overload and stall. The constant horsepower control simultaneously regulates the combined power of both pumps, so even when only one pump is loaded, maximum engine output power can still be utilized. Additionally, optional power shift control provides dual power curve switching to suit light- and heavy-load conditions.

4. Compact Construction & Internal Drain Design

The PVD series features an extremely short overall length, facilitating installation in the limited engine compartments of compact excavators. The internal drain structure is standard, eliminating the need for external drain piping, simplifying system layout, and reducing potential leak points. The housing is cast from high-strength cast iron, providing excellent rigidity and vibration resistance under frequent impact loads on construction sites. Internal friction pairs are manufactured with high-precision grinding technology, ensuring low leakage and long service life even under high pressure and harsh dusty conditions.

5. High Volumetric Efficiency & Low Noise Operation

The axial piston pump architecture ensures sustained efficiency exceeding 90% across high-pressure regimes. Pistons and cylinder bores are precision-matched with micron-level clearances, effectively minimizing internal leakage. The valve plate transition zone is optimized to pre-pressurize the piston chamber before it connects with the discharge port, significantly reducing fluid-borne noise from pressure transients and maintaining low noise levels among comparable products.

Application Areas

• Mini Excavators: Takeuchi TB135, Kubota U30-6/U35, Yanmar, IHI, and other ≤4-ton class mini excavators — main hydraulic pump

• Compact Construction Equipment: Mini skid steer loaders, compact wheeled excavators, micro crawler excavators — main hydraulic power source

• Municipal & Landscape Machinery: Small maintenance equipment, landscaping machinery hydraulic drive systems

• Agricultural Machinery: Small tractor auxiliary hydraulic systems

The PVD-15B series is specifically developed for 1 to 6-ton mini excavators, with two equal-flow circuits driving the travel motor and work equipment circuits respectively, enabling precise straight-line travel and compound action control in confined working spaces.

Expert Maintenance Tips

Pre-Installation Check: Before installation, the pump case must be filled with clean ISO VG46 anti-wear hydraulic oil. Internal bearings and high-speed sliding components (including piston shoes and spherical bushings) require continuous lubrication — never dry-start the pump. All pipes and tubing must be thoroughly cleaned before installation.

Coupling Alignment: The coaxiality deviation (TIR) between pump shaft and engine flywheel shaft must be controlled within 0.05 mm. Misalignment leads to premature bearing wear, shaft seal leakage, and abnormal noise. Flexible couplings must be used; never use tire-type couplings.

Fluid Cleanliness Management: System oil cleanliness must achieve ISO 4406 18/16/13 or higher. Contamination is the primary cause of premature piston pump failure. Install high-precision return-line filters and inspect regularly. ISO VG32 or VG46 anti-wear hydraulic oil is recommended; operating oil temperature should be maintained between 10 and 60°C.

Internal Drain Design Note: The PVD-15B series utilizes internal drain design, eliminating the need for an external case drain line. However, ensure the drain passage at the pump mounting position is unobstructed; the pump body must not be blocked by foreign objects or sealant blocking the drain port.

First Start-up & Air Purge Procedure: After initial installation or extended shutdown, perform the air purge procedure. First check hydraulic oil level, open the air bleed screw on the pump body, run the engine at idle for approximately 15 minutes, then slowly increase speed for another 15 minutes after bubble-free oil flows out, and only apply load after confirming complete air expulsion.

Periodic Inspection: Every 1,000 to 3,000 operating hours or six months, inspect pump operating conditions including oil temperature, pressure, flow, and vibration. The first hydraulic oil change should be performed after 3 months of operation, then annually or when contamination is detected. Inspect suction and return filter elements; blocked filters cause cavitation and abnormal noise.

Troubleshooting Priority: If abnormal noise or temperature rise occurs during operation, inspect in the following order: ① Excessive air content in hydraulic fluid; ② Blocked suction filter; ③ Coupling misalignment exceeding tolerance; ④ Internal bearing or piston pair wear.