PVD-15B-32BP-9AG5-4634G Nachi Hydraulic Pump 19cc/rev 2600rpm

Product Overview

The PVD-15B-32BP-9AG5-4634G and PVD-15B-37P-9AG5-5599B belong to the Nachi PVD Series of variable split-flow axial piston pumps, purpose-built for 1–6 ton class mini excavators. The PVD Series features a unique single-pump architecture that delivers two equal flow streams through coaxial output, with flow deviation between circuits controlled to within 1% — fundamentally ensuring excavator straight-line travel stability. Constant horsepower control is integrated as standard equipment, and the internal drain design eliminates the need for external drain piping, making the pump compact enough for confined engine compartments.

Our products are manufactured to original Nachi technical specifications with full drop-in interchangeability. The PVD-15B-32BP-9AG5-4634G is a direct replacement for the Takeuchi TB135 excavator main pump (OEM part # 19020-16100), while the PVD-15B-37P-9AG5-5599B fits Kubota and other mini excavator applications. Every pump undergoes 100% simulated load testing at the factory, covering pressure hold, dual-circuit flow balance, and constant horsepower control valve dynamics for seamless replacement and reliable operation in demanding job sites.

Technical Specifications 

• Series: Nachi PVD Series

• Design: Variable split-flow axial piston pump, swashplate type, dual-circuit equal output

• Displacement per Circuit: 19 cm³/rev

• Total Theoretical Displacement: 38 cm³/rev (both circuits combined)

• Rated Continuous Pressure: 21 MPa (210 bar)

• Maximum Intermittent Peak Pressure: 24.5 MPa (245 bar)

• Maximum Allowable Speed: 2,600 rpm

• Rated Operating Speed: 2,400 rpm

• Minimum Speed: 900 rpm

• Control Type: Constant horsepower control (standard equipment); optional power shift (total horsepower control)

• Drain Type: Internal drain — no external drain piping required

• Applicable Excavator Class: ≤4.0 ton

• Pump Body Reference Weight: Approx. 38 kg

• Optional Configurations: Gear pump (single/dual), valve block

Model Code Interpretation (Examples):

• PVD-15B-32BP-9AG5-4634G: PVD-15B pump body size, 32BP as total nominal displacement and standard configuration code, 9AG5 as control type / interface specification / gear pump configuration code, 4634G as design number and customization suffix — corresponds to Takeuchi TB135 OEM adaptation.

• PVD-15B-37P-9AG5-5599B: PVD-15B pump body size, 37P as total nominal displacement and configuration code, 9AG5 as control and interface specification, 5599B as design number — corresponds to Kubota mini excavator adaptation.

Data based on Nachi PVD Series technical documentation. Maximum working pressure is uniformly 24.5 MPa across the series, with constant horsepower control as standard equipment.

Key Technical Advantages

1. Dual-Circuit Equal Flow Design — Ensures Straight-Line Travel

The defining engineering feature of the PVD Series is its single-pump coaxial dual-circuit equal output architecture. Conventional solutions employ two separate pumps in series, where flow deviation between circuits is governed by manufacturing tolerances. The PVD Series delivers two identical flow streams from a single pump body, with port-to-port flow variation controlled to within 1% — fundamentally eliminating left-right travel motor flow imbalance and ensuring trajectory accuracy during straight-line excavator travel. This design also simplifies hydraulic circuit routing and reduces potential leak points.

2. Constant Horsepower Control — Full Engine Power Utilization

The PVD Series integrates constant horsepower control as standard equipment. This control mechanism adjusts swashplate tilt angle based on the combined power output of both pump circuits. Even when only one circuit is under load, the constant horsepower control still maximizes engine power utilization, improving machine speed and productivity. The optional power shift (total horsepower control) mode further extends the pump’s power regulation range to suit varying operating conditions.

3. Internal Drain Structure and Compact Design

The PVD Series employs an internal drain structure, with case leakage returning to the reservoir through internal passages — no external drain lines required. This design reduces the number of external fittings and potential leak points while significantly shortening overall pump length for easy installation in space-constrained mini excavator engine compartments. The base pump body weighs approximately 38 kg, offering clear power density advantages among comparable dual-circuit pumps.

4. Axial Piston Architecture and High-Efficiency Operation

The PVD Series utilizes swashplate-type axial piston architecture, maintaining high efficiency (η ≥ 90%) across high-pressure operating regimes. Piston pairs are manufactured from high-strength alloy steel with precision-honed cylinder bores, sustaining stable volumetric efficiency at 24.5 MPa peak pressure. Optional rear-mounted gear pumps (single or dual) can be integrated on the back of the piston pump to power auxiliary hydraulic circuits, further enhancing system integration.

Application Areas

• Mini Excavator Main Pump: 1–6 ton class mini excavator travel, swing, boom, arm, and bucket hydraulic drive

• Compatible OEM Machines: Takeuchi TB135 (PVD-15B-32BP-9AG5-4634G, OEM part # 19020-16100), Kubota KX91-2/KX91-2S, Kubota U30-6, and other mini excavators

• Municipal Engineering Machinery: Compact municipal excavators, micro-tunneling equipment auxiliary hydraulic systems

• Agricultural Machinery: Small tractor hydraulic hitch and steering systems

• Industrial Hydraulic Power Units: Compact hydraulic power packs, machine tool auxiliary hydraulic systems

Expert Maintenance Tips

Pre-Installation Inspection: Before installing PVD-15B Series pumps, verify hydraulic system cleanliness meets ISO 4406 18/16/13 or better. Port plugs should be removed and piping connected immediately after unboxing — environmental exposure should not exceed 15 minutes. Before first start, fill the pump case with clean hydraulic oil to the maximum allowable level. Dry-start is strictly prohibited. Since the PVD Series uses internal drain structure, no external drain line connection is required during installation, but adequate oil level in the pump case must be ensured.

Operating Oil Temperature Management: The PVD Series recommended operating oil temperature range is 15–60°C. When starting with oil temperature below 15°C, warm the hydraulic oil or run at low speed and low load until oil temperature reaches 15°C before applying full load. Prolonged operation above 60°C accelerates seal aging and fluid degradation — inspect the cooling system if oil temperature consistently exceeds this threshold.

Constant Horsepower Control Valve Calibration: The PVD Series constant horsepower control mechanism regulates the combined power output of both pump circuits. During calibration, monitor both outlet pressures with separate gauges and verify power matching under simultaneous dual-circuit loading conditions. The objective of constant horsepower control is to keep total pump drive power below the engine power curve to prevent engine stall. After control valve replacement or major overhaul, verify dual-circuit synchronization in accordance with Nachi factory test standards.

Oil Maintenance Schedule: Replace hydraulic oil and filter after the first 500 hours of operation. Thereafter, replace every 2,000 hours or 12 months, whichever comes first. Recommended viscosity grade: VG 32–68 mineral hydraulic oil, viscosity range 10–200 cSt. If the system is equipped with an online particle counter, replace oil and inspect filter differential pressure immediately when cleanliness drops to ISO 4406 20/18/15.

Long-Term Storage Protection: For pumps stored over 3 months, drain case oil, fill with rust-preventive oil, and plug all ports. Before recommissioning, flush with flushing oil for 30 minutes and confirm flushing oil cleanliness meets specification before connecting to the system. Always refill the case to the maximum allowable level before restart.