Nachi IPH Series High Pressure Internal Gear Pump IPH-2B-5-11 IPH-2B-6.5-11 IPH-2B-8-11

The industrial-grade Nachi Compatible IPH Series High-Pressure Internal Gear Hydraulic Pumps, engineered by Chengyuan Hydraulic, are recognized as benchmark fluid power components for applications requiring ultra-low noise, high pressure preservation, and long-term mechanical survival. Operating as the primary power component within modern micro-positioning servo networks, this series incorporates a unique fluid dynamic profile and dual radial/axial clearance compensation technology to eliminate the high-pressure flow pulsations and acoustic chattering typical of traditional external gear designs.

This professional B2B product documentation profiles and directly replaces Nachi’s original factory IPH-2B series size 2 configurations, specifically focusing on the high-demand reference codes: IPH-2B-5-11, IPH-2B-6.5-11, and IPH-2B-8-11 (where “IPH” specifies the internal gear high-pressure configuration, “2B” denotes the size 2 frame platform, “5 / 6.5 / 8” represents the target geometric displacements, and “-11” designates the optimized latest generation engineering platform revision). These precise pumps are widely selected for energy-efficient servo hydraulic stations, heavy CNC sheet metal press brakes, automated testing stands, and assembly line manifolds with strict acoustic boundaries.

Chengyuan’s alternative internal gear pumps align perfectly with authentic Nachi installation dimensions, featuring standard SAE 2-bolt mounting flanges, straight keyed driveshafts, and side-mounted four-bolt split flange port distances. B2B purchasing agents and OEM machinery builders can perform rapid field swap-outs onto existing electric motor blocks without modifying custom steel adapter structures or high-pressure piping links.

High-pressure internal gear pumps maintain exceptionally tight internal tolerances and often operate under demanding conditions, including continuous peak loading up to 300 bar, fluctuating servo-driven rpm cycles, or extended high-pressure dwell phases. Lower-grade alternatives often fail due to loose tolerances across their clearance-compensation components, resulting in rapid volumetric efficiency degradation and sharp fluid vibration noise. To ensure dependable operational safety, 100% of Chengyuan’s IPH series replacement pumps undergo 100% strict dynamic load testing on digitized simulation benches. Each pump is verified under full system pressure to validate thermal volumetric output, casing temperature profiles, and micron-level flow stability before packaging.

Technical Specifications

• Product Classification: High-Performance Fixed Displacement Internal Gear Hydraulic Pump

• Compatible Reference Platform Series: Nachi IPH Series Size 2B Framework Group

• Geometric Displacement Configurations per Model Code:

  • Replacement Reference: IPH-2B-5-11: Displacement calibrated at 5.2 cc/rev

  • Replacement Reference: IPH-2B-6.5-11: Displacement calibrated at 6.5 cc/rev

  • Replacement Reference: IPH-2B-8-11: Displacement calibrated at 8.1 cc/rev

• Maximum Rated Continuous Operating Pressure: 250 bar (25 MPa / 3625 psi)

• Maximum Permissible Peak Intermittent Pressure: Up to 300 bar (30 MPa / 4350 psi)

• Operational Rotational Speed Horizons: Minimum 600 rpm, with continuous maximum speeds up to 3000 rpm (optimized for fast servo motor acceleration profiles)

• Target Volumetric Efficiency Rating: $\ge 96\%$ under full continuous high-temperature load conditions

• Input Drive Shaft Configuration: Standard straight cylindrical keyed shaft matching original 2B framework specifications

• Mounting Flange Matrix Alignment: Standard SAE A 2-bolt mounting configuration

• Fluid Suction & Discharge Interface Setup: Side-mounted standard 4-bolt split flange interfaces with metric retaining threads

• Fluid Medium Compatibility & Viscosity Horizons: Premium mineral-based anti-wear hydraulic fluids (HLP), supporting operating viscosities from 20 cSt to 150 cSt

• Acoustic Emissions Index: Maintained between 50 dB(A) and 58 dB(A) under full continuous pressure (exceptionally low-noise performance)

Key Technical Advantages

• Hydraulic Radial and Axial Dual-Clearance Compensation Systems: The pump interior features a precision floating crescent seal paired with hydrostatically balanced axial thrust plates. This setup utilizes high-pressure fluid from the discharge port to automatically adjust internal clearances in real time based on system load. Even at continuous 250 bar operations, internal bypass leakage is minimized to maintain high volumetric efficiency.

• Involute Short-Crest Internal Gear Set Geometries: The driving pinion and internal ring gear are forged from high-alloy steel, case-hardened via carbonitriding, and finished on CNC internal profile grinders. The specialized short-crest involute profiles minimize fluid trapping during gear meshing, reducing flow pulsation by over 70% compared to external gear pumps to eliminate a major source of system resonance.

• Hydrodynamic Force-Fed Journal Bushing Supports: The main drive shaft is supported by high-rigidity hydrodynamic sliding journal bearings instead of standard rolling elements. These bushings are continuously cooled and lubricated via high-pressure fluid channels that suspend the rotating shaft on a rigid fluid film, providing excellent shock resistance and preventing binding under continuous heavy loads.

• Nodular Cast Iron Acoustic Casing Matched with Low-Resistance Fluid Channels: The main housing is cast from high-grade nodular iron (QT600) to ensure high structural rigidity. This design prevents wall deformation under intense pressure cycles, while the internal flow passages are shaped to damp high-frequency cavitation noise for quiet operation under full continuous loads.

Application Areas

Chengyuan’s high-performance replacement Nachi IPH series internal gear pumps provide stable, low-noise fluid power across demanding industrial automated applications:

• Energy-Efficient Eco-Drive Servo Hydraulic Systems: Providing reliable power for high-tonnage injection molding machinery, blow-molding equipment, and automated die-casting cells.

• Precision CNC Metal Forming & Press Brakes: Delivering pulse-free fluid flow to maintain micrometer-level positioning accuracy for heavy sheets during bend cycles.

• High-End Automated Testing Stands & Laboratory Systems: Serving as a quiet, stable fluid reference source for proportional servo valve calibration blocks and component fatigue testing.

Expert Maintenance Tips

• Because the IPH Internal Gear Pump Features Micrometer-Level Tolerances, It Is Highly Sensitive to Particulate Contamination; Always Maintain Fluid Cleanliness at NAS Class 7 (or ISO 4406 17/14/11) or Better: Fine abrasive particles entering the pump can score the floating plates or crescent seals. This creates internal bypass paths that cause permanent loss of discharge pressure and excessive oil heating.

• Always Pre-Fill the Pump with Clean, Filtered Hydraulic Oil via the Suction Port Prior to Initial Operation; Never Dry-Start or Jog the Drive Motor: The internal gear profiles and hydrodynamic journal bearings rely on immediate fluid film lubrication. Running the pump dry—even during initial jogging cycles before fluid is drawn from the reservoir—can cause rapid frictional heating and damage the bimetallic floating side faces.

• Utilize a Properly Rated Flexible Coupling for Motor Alignment, and Never Use a Hammer or Impact Tool to Force Components onto the Drive Shaft: Impact forces applied directly to the shaft can shift the assembly axially. This internal movement damages the precision thrust washers and clearance compensation components, which can cause increased internal leakage and audible ticking noises during operation.