Nachi Hydraulic Pump Guide: Specifications, Applications & Replacement Selection

Nachi hydraulic pumps are widely used in mini excavators, construction machinery, machine tools, industrial hydraulic power units, and automated production equipment. Common series include PVD, PVK, PVS, PZS, PZH, PZ, IPH, VDS, VDR, and VDC.

Different Nachi hydraulic pump series vary significantly in structure, displacement, operating pressure, control methods, and applications. Even within the same series, different models may have different mounting dimensions, input shafts, and control configurations.

Therefore, whether purchasing a new Nachi hydraulic pump, looking for a replacement for an existing pump, or buying repair parts such as pistons, cylinder blocks, valve plates, and seals, it is essential to correctly identify the pump model and technical specifications.

This guide covers the main Nachi hydraulic pump series, technical features, applications, model identification methods, and important considerations when selecting replacement pumps and repair parts.

Nachi Hydraulic Pump Models & Series

Nachi hydraulic pumps are mainly divided into three types:

• Piston Pump: Suitable for medium- and high-pressure hydraulic systems. Some models support variable displacement, constant horsepower control, and load-sensing control.
• Vane Pump: Known for smooth operation, compact construction, and low noise levels. They are primarily used in industrial hydraulic systems.
• Gear Pump: Feature a relatively simple structure. NACHI IPH internal gear pumps are mainly designed for low-noise, high-efficiency industrial hydraulic applications.

Nachi Hydraulic Pump Series Comparison

Series	Pump Type	Main Features	Applications
PVD	Construction machinery piston pump	Dual-flow output, constant horsepower control	Mini excavators
PVK	Variable displacement piston pump for construction machinery	Constant horsepower control, optional load-sensing control	Mini excavators and construction machinery
PVS	Variable displacement piston pump	Low noise, energy efficiency, compact design	Industrial hydraulic power units, machine tools
PZS	Variable displacement piston pump	Medium to large displacement, low vibration	Industrial machinery, hydraulic equipment
PZH	High-pressure variable displacement piston pump	High-pressure design, high power density	High-pressure industrial hydraulic systems
PZ	Load-sensing variable displacement piston pump	Adjusts flow according to load demand	Industrial hydraulic systems
IPH	Internal gear pump	Low noise, high efficiency	Machine tools, industrial hydraulic power units
VDS	Compact variable displacement vane pump	Small displacement, compact design	Small industrial hydraulic equipment
VDR	Variable displacement vane pump	Low noise, smooth operation	General industrial machinery
VDC	High-pressure variable displacement vane pump	Higher operating pressure, variable displacement control	Industrial hydraulic equipment

Nachi Piston Pump Series: PVD, PVK, PVS, PZS, PZH, and PZ

Nachi PVD Series: Piston Pumps for Construction Machinery

The PVD series is primarily used in mini excavators and other construction machinery. It features a dual-flow design that provides two separate flow outputs to meet the requirements of combined machine movements and travel control.

Applications: Mini crawler excavators and compact construction machinery equipped with compatible hydraulic systems.

Nachi PVK Series: Variable Displacement Piston Pumps for Construction Machinery

The PVK series is mainly designed for construction machinery hydraulic systems. It features a variable displacement design that adjusts hydraulic pump output according to operating conditions and control requirements.

Applications: Mini excavators, construction machinery, and equipment equipped with compatible variable displacement control systems.

Nachi PVS Series: Low-Noise Variable Displacement Piston Pumps

The PVS series is commonly used in NACHI industrial hydraulic applications. It features a variable displacement piston design and optimized swash plate, valve plate, and internal components to reduce operating noise and vibration.

Applications: Machine tools, industrial hydraulic power units, automated production equipment, and other stationary industrial hydraulic systems.

Nachi PZS Series: Medium- to Large-Displacement Variable Piston Pumps

The PZS series is primarily used in industrial equipment requiring reliable hydraulic flow and stable performance. Its optimized piston mechanism and valve plate design help improve operating efficiency while reducing noise and vibration.

Applications: Industrial hydraulic power units, pressure equipment, and other medium- to large-scale hydraulic machinery.

Nachi PZH Series: High-Pressure Variable Displacement Piston Pumps

The PZH series is designed for industrial hydraulic systems requiring higher operating pressures.

Compared with conventional industrial variable displacement piston pumps, high-pressure hydraulic pumps have specific design requirements for structural strength, sealing performance, and the load-bearing capacity of internal components.

Applications: High-pressure industrial hydraulic power units, industrial processing equipment, and other systems requiring high-pressure hydraulic power.

Nachi PZ Series: Load-Sensing Variable Displacement Piston Pumps

The PZ series uses load-sensing control to adjust output according to the actual load and flow requirements of the hydraulic system.

Compared with hydraulic systems that continuously deliver a fixed flow rate, load-sensing control can help reduce unnecessary throttling losses when properly implemented.

Applications: Industrial hydraulic equipment, automated machinery, and hydraulic power systems requiring on-demand flow delivery.

Nachi Vane Pump and Gear Pump Series

VDS Series: Compact Variable Displacement Vane Pumps

The VDS series features a compact design, low noise levels, and variable displacement output, making it suitable for small industrial hydraulic systems with limited installation space.

Common applications include small machine tools, workholding fixtures, and auxiliary hydraulic power equipment.

VDR Series: Industrial Variable Displacement Vane Pumps

The VDR series consists of industrial variable displacement vane pumps designed for hydraulic equipment requiring stable pressure and low noise levels.

VDC Series: High-Pressure Variable Displacement Vane Pumps

The VDC series is designed for industrial hydraulic systems requiring higher operating pressures. Its main features include variable displacement control, low-noise design, and internal components suitable for the specified pressure range.

IPH Series: Internal Gear Pumps

The IPH series is one of Nachi’s representative internal gear pump product lines. It offers high efficiency, low noise levels, and smooth operation, making it suitable for industrial hydraulic power units, machine tools, and other hydraulic power equipment.

What Should You Check When Selecting a Nachi Hydraulic Pump?

The differences between Nachi hydraulic pump series are not limited to their appearance and internal structure. They also involve operating parameters and control configurations.

Technical Parameter	Why It Matters
Displacement	Determines the theoretical oil volume delivered per revolution
Rated Pressure	Determines whether the pump meets continuous operating pressure requirements
Maximum Pressure	Confirms short-term pressure limits and safe operating range
Operating Speed Range	Determines compatibility with the driving engine or motor
Control Method	Affects flow, pressure, and load response
Rotation Direction	Affects input shaft rotation and proper installation
Mounting Flange	Determines whether the pump can be installed on the original equipment
Input Shaft	Confirms spline specifications, keyway, shaft diameter, and other dimensions
Port Dimensions	Ensures proper hydraulic line connections

How to Identify a Nachi Hydraulic Pump Model Number?

Correctly identifying the hydraulic pump model is essential when purchasing complete pumps and repair parts.

Take PVS-1B-16N2-U-12 as an example. The model number consists of several letters and numbers representing different specifications.

How to Choose the Right Nachi Hydraulic Pump Replacement?

Confirm the Original Pump Model First

The most direct method is to identify a replacement pump with the same configuration based on the original pump nameplate and complete model number.

What If the Original Model Has Been Discontinued?

If the original Nachi hydraulic pump model has been discontinued, consider the following options:

Confirm the Original Pump Model First

The most direct method is to identify a replacement pump with the same configuration based on the original pump nameplate and complete model number.

What If the Original Model Has Been Discontinued?

If the original Nachi hydraulic pump model has been discontinued, consider the following options:

• A newer design version within the same series.
• A manufacturer-approved replacement model.
• A technically verified compatible replacement pump.

When using an alternative replacement, hydraulic specifications, mechanical interfaces, and control configurations must be carefully checked.

Nachi Hydraulic Pump Repair Parts: Which Components Can Be Replaced?

Some Nachi hydraulic pumps can be repaired by replacing worn or damaged internal components, depending on the specific model and extent of damage.

Common hydraulic pump repair parts include:

• Piston Shoe
• Cylinder Block
• Valve Plate
• Swash Plate
• Retainer Plate
• Slipper
• Bearing
• Shaft
• Seal Kit
• Regulator

Not all repair parts are suitable for every Nachi hydraulic pump series. For example, pistons, cylinder blocks, and swash plates are primarily used in piston pumps with the corresponding internal structure.

When Should You Purchase Repair Parts?

If the hydraulic pump has only localized component damage and the pump housing, input shaft, and other critical components remain in good condition, a repair kit can be purchased after professional inspection.

When Should You Replace the Complete Hydraulic Pump?

• Severe damage to the pump housing or critical structural components.
• Extensive wear affecting multiple internal rotating components.
• Widespread internal damage caused by metal debris.
• Repair costs approaching the cost of a complete replacement pump.
• Essential repair parts are no longer available.

What Information Is Required Before Purchasing a Nachi Hydraulic Pump or Repair Parts?

Purchasing a Hydraulic Pump

• Complete Nachi hydraulic pump model number or a photo of the original pump nameplate.
• OEM part number.
• Photos of the pump body and mounting interfaces, or overall product photos.

Purchasing Hydraulic Pump Repair Parts

• Complete hydraulic pump model number.
• Names and quantities of the required parts.
• Photos of the original parts.
• Relevant component dimensions or identification markings.

If you are unsure which component is required, you can also provide photos of the hydraulic pump and information about the problem for further verification.

Conclusion

Nachi hydraulic pumps include piston pumps for construction machinery, industrial variable displacement piston pumps, vane pumps, and internal gear pumps.

The PVD and PVK series are primarily designed for compact construction machinery, while the PVS, PZS, PZH, and PZ series are used in various industrial hydraulic systems. The IPH, VDS, VDR, and VDC series meet the hydraulic power requirements of other industrial equipment.

When selecting a Nachi hydraulic pump or repair parts, accurately identifying the model number, checking technical specifications, and confirming installation compatibility are essential.

If you are unsure whether you need a pump or repair parts, please send your part number and requirements to Farinparts; our team will assist you in selecting the most suitable product.