Premium Industrial Hydraulic Gear Pumps | High-Performance Replacement & Custom OEM Solutions

1. What Is a Gear Pump?

A hydraulic gear pump is a robust, positive-displacement mechanical unit engineered to convert mechanical input into hydraulic fluid power through the synchronized meshing of two or more high-precision gears inside a close-tolerance housing.

How It Operates: As the gears rotate, fluid enters through the suction (inlet) port and fills the expanding cavities between the gear teeth and internal housing walls. The fluid is carried smoothly along the outer circumference of the gears to the discharge (outlet) port, where the re-meshing teeth displace the fluid under pressure into the hydraulic system.

Why Gear Pumps Dominate the Global Fluid Power Market:

• Exceptional Power Density: Compact footprint delivering high pressure and substantial flow output without excessive weight.

• Cost-Efficient Durability: Engineered with fewer moving parts for simplified maintenance, reduced operating costs, and extended service intervals.

• Superior Contamination Tolerance: Highly resilient in real-world operating conditions with particulate exposure compared to sensitive piston or vane pumps.

• Consistent, High Volumetric Efficiency: Optimized internal clearances ensure steady, nearly pulse-free flow even under fluctuating thermal and load conditions.

2. Types of Gear Pumps: Mechanical Configurations

Gear pumps are primarily categorized into two distinct families based on internal gear architecture, each suited for targeted operating envelopes:

① External Gear Pumps (The Workhorse of Hydraulics)

Configuration: Features two identical, precision-cut interlocking gears (a driving gear and an idler gear), each mounted on its own heavy-duty shaft and supported by low-friction hydrodynamic or roller bushings.

Key Advantages: Wide displacement flexibility, high operating pressure resilience, simple serviceability, and unmatched cost-to-performance ratio.

Primary Use: The universal industry standard for mobile machinery, earthmoving equipment, agricultural attachments, lubrication circuits, and industrial power units.

② Internal Gear Pumps (Low Noise & High Viscosity Specialist)

Configuration: Utilizes an inner drive rotor meshing eccentrically inside an outer internal ring gear, with a precision-machined crescent partition separating the suction and pressure zones.

Key Advantages: Exceptionally quiet acoustic footprint, virtually pulsation-free discharge, low shear stress, and unmatched suction capability for high-viscosity media.

Primary Use: Indoor manufacturing plants, plastic injection molding, CNC hydraulic systems, chemical metering, and noise-sensitive municipal machinery.

Available Configurations to Match Every System:

• Displacement Modes: Standard fixed-displacement units and specialized variable-displacement solutions.

• Multi-Stage & Tandem Power: Available in single-section, double, triple, and multi-section designs to drive multiple independent hydraulic circuits from a single prime mover.

• Rotation Flexibility: Clockwise (CW), Counter-Clockwise (CCW), and fully bi-directional (reversible) models for versatile integration.

3. Demanding Industry Applications

Engineered to operate continuously under severe shock loads, extreme temperatures, and harsh jobsite conditions, our gear pumps power critical hydraulic functions worldwide:

Construction & Earthmoving Machinery: Main & auxiliary circuits in excavators, mini-excavators, wheel loaders, backhoes, motor graders, and mobile cranes.

Agricultural & Forestry Equipment: Steering, three-point hitches, lifting arms, and auxiliary hydraulic functions in tractors, combine harvesters, balers, and timber handlers.

Material Handling & Logistics: Mast elevation, carriage tilting, and auxiliary attachments for counterbalance forklifts, pallet stackers, reach trucks, and scissor lifts.

Mining & Heavy Drilling Machinery: Surface and underground drilling rigs, rock crushers, conveyors, and heavy tunneling machinery.

Municipal, Waste & Road Maintenance: Street sweepers, garbage compaction trucks, salt spreaders, snow plows, and highway repair platforms.

Industrial Manufacturing Systems: Heavy hydraulic presses, CNC machine tool feeds, automated assembly fixtures, centralized lubrication skids, and hydraulic power units (HPUs).

Marine, Forestry & Off-Highway Platforms: Winch control, marine steering gears, log splitters, and rough-terrain transport vehicles.

4. Key Performance Features & Engineering Advantages

High Volumetric Efficiency with Low Pulsation: Precision gear profiling and optimized relief grooves eliminate fluid trapping, reduce internal turbulence, and guarantee steady, high-efficiency output.

High Power Density in a Lightweight Body: High-tensile extruded aluminum alloy or heavy-duty ductile iron bodies deliver maximum pressure endurance with minimum total weight.

Hardened Precision Gears & Extended Bearing Life: Gears are case-hardened, micro-finish ground, and heat-treated to resist cavitation, wear, and mechanical fatigue over millions of cycles.

Excellent Fluid Contamination Tolerance: Engineered internal hydrodynamic balancing plates maintain micron-level sealing while tolerating typical industrial particulate contamination.

100% 1:1 Direct Interchangeability: Built strictly to international dimensional standards (SAE, ISO, DIN), ensuring immediate drop-in replacement without piping or mounting modifications.

Pre-Shipment Pressure Bench Testing: Every single unit undergoes computerized pressure-holding, flow validation, and seal-integrity testing before leaving our facility.

5. Technical Specifications (Techspecs)

Our gear pump portfolio offers extensive dimensional and performance modularity to meet exact engineering specifications:

Note: Specific displacement, pressure, and mounting combinations can be customized. Contact our technical team for the complete engineering datasheet of any specific model.

6. Seamless Direct-Fit Replacement for Global Brands

Eliminate Costly Machine Downtime & High OEM Markups

Waiting weeks for expensive original brand gear pumps can cripple your operations. Hengyuhang Hydraulics manufactures premium direct-fit replacement pumps that match the mounting dimensions, shaft extensions, port locations, and hydraulic performance curves of leading global manufacturers—at competitive factory-direct pricing.

Comprehensive Cross-Reference Brand Coverage:

We provide 1:1 interchangeable replacement units for:

• A – B: ARGO-HYTOS, ASEDA, ATOS, B&C, BLUEASCEND, Boden, BONDIOLI, Brevini, BUCHER

• C – D: Caproni, CASAPPA, CONCENTRIC, DANFOSS, DAVID BROWN, DUPLOMATIC

• E – H: ECKERLE, Galtech, GPD, GRH, HANSA-TMP, HESPER, HIDRAULICA, HOERBIGER, HONOR, HPI, HYDAC, HYDRECO, HYDROMAX, HYDRONIT, HYTEK

• J – M: JCB, JIHOSTROJ, JOYANG, KOMPASS, KOMATSU, KRACHT, MARZOCCHI, MetaHydra, METARIS

• N – P: NACHI, NIHON SPEED, OKDO, PARKER, PERMCO

• R – S: REXPOWER, Rexroth, REXROTH-SIGMA, RONZIO, ROQUET, SALAMI, SCENERY, SDH, SETTIMA, SHIMADZU, STEIMEL, SUMITOMO, SUNNY

• V: VIVOLO, VOITH

Direct Match Guarantee: Simply provide your existing pump model number, nameplate photo, or equipment brand, and our engineering team will identify the exact drop-in replacement within hours.

7. Step-by-Step Gear Pump Selection Guide

To ensure optimal performance, efficiency, and longevity, verify the following core parameters when choosing your gear pump:

1. Calculate Required Flow Rate (Q): Determine your required actuator speed to select the right displacement (cc/rev) at your prime mover's operating speed (rpm).

2. Confirm Working & Peak Pressures: Ensure the pump's continuous pressure rating meets your normal operating load, with adequate peak pressure overhead (up to 300 bar) for transient relief spikes.

3. Verify Drive Speed & Rotation Direction: Match the prime mover speed (400 – 3000 rpm) and check rotation facing the drive shaft: Clockwise (Right-Hand / CW) or Counterclockwise (Left-Hand / CCW).

4. Select Mechanical Interfaces: Verify mounting flange pattern (SAE A/B/C or ISO 4-bolt) and shaft style (involute spline, keyed, or tapered) for zero-clearance coupling.

5. Determine Port Configuration: Confirm thread type (BSPP, Metric) or split flange, port size, and whether side or rear ports best fit your space envelope.

6. Evaluate Operating Media: Check operating temperature (−20 °C to +80 °C) and fluid viscosity (12 – 800 cSt) to select standard NBR or high-temperature Viton seals.

7. Single vs. Multiple Stages: Determine if a single pump or a space-saving tandem multi-section pump is required to operate distinct sub-circuits.

Unsure about the exact specifications? Share your application requirements or machine photos, and our fluid power engineers will calculate and specify the ideal pump for you.

8. High-Capacity OEM & Private-Label Manufacturing Services

Scale your business with Hengyuhang's full-spectrum OEM and ODM customization services. We support global equipment manufacturers, distributors, and aftermarket parts brands with end-to-end production capabilities:

Custom Hydraulic Engineering: Build from client-supplied CAD drawings or collaborate with our R&D engineers to design customized displacement, non-standard mounting flanges, or integrated valve blocks (pressure relief or check valves).

Flexible Private-Label Branding: Laser engraving of custom brand logos, customized model numbering, tailored nameplates, and bespoke export packaging.

From Rapid Prototyping to Volume Mass Production: Rapid sample prototyping and testing benches ensure rapid verification before launching into recurring container-volume production.

Strict Quality Consistency: Comprehensive quality control protocols across raw material sourcing, CNC precision machining, heat treatment, assembly, and 100% end-of-line pressure testing.

9. About Hengyuhang Hydraulics – Your Trusted Manufacturing Partner

Hengyuhang is an established, professional hydraulic gear pump manufacturer and global supply partner. With extensive precision manufacturing facilities and a dedicated team of fluid power specialists, we deliver:

Advanced Precision Production Lines: Equipped with high-precision CNC machining centers, specialized gear hobbing and grinding equipment, and automated inspection tools.

Dependable Global Supply Chain: Delivering reliable, defect-free hydraulic products to distributors, repair workshops, and machinery builders across Europe, North America, South America, and Asia.

Competitive Factory-Direct Pricing: Maximum performance and reliability without unnecessary intermediary markups.

Fast Response & Reliable Lead Times: Large stock of standard components for rapid assembly and expedited international shipping.

10. Frequently Asked Questions (FAQ)

Q1: What is a gear pump primarily used for?

A: Gear pumps are positive-displacement units used to transfer and pressurize hydraulic fluid across mobile, industrial, agricultural, and marine machinery. Common applications include lifting, steering, auxiliary attachments, and continuous lubrication circuits.

Q2: Can Hengyuhang gear pumps directly replace original international brand units?

A: Yes, 100%. Our replacement pumps are manufactured to identical dimensional, mounting, and performance standards as brands like Rexroth, Parker, Casappa, Danfoss, Marzocchi, Bucher, and Salami. They provide a seamless "drop-in" replacement without modifying hydraulic lines, brackets, or couplings.

Q3: What essential details do I need to provide when ordering a replacement pump?

A: The easiest method is to send a photo of your existing pump nameplate or the model code. If the nameplate is missing, provide:

• Displacement (cc/rev) or required flow output.

• Operating pressure (bar).

• Operating speed (rpm) and direction of rotation.

• Mounting flange style, shaft dimensions, and port thread/flange size.

Q4: Do you offer custom engineering or private-label OEM manufacturing?

A: Yes. We provide comprehensive OEM/ODM manufacturing. Clients can provide their own technical drawings, or our engineering team can design to your operational requirements. We also offer private labeling, laser logo engraving, and customized packaging.

Q5: What is the Minimum Order Quantity (MOQ) for OEM/custom orders?

A: We maintain flexible MOQs tailored to your specific requirements. We support initial prototype sample orders for testing and validation, as well as recurring scheduled batch orders for volume distribution.

Q6: What is the expected service life of a Hengyuhang gear pump?

A: Under recommended operating conditions, proper hydraulic oil viscosity (12 – 800 cSt), and standard system filtration (ISO 4406 Class 19/17/14 or better), our pumps provide years of dependable, trouble-free service life, backed by precision-ground, case-hardened gears and durable friction-reducing bushings.

Q7: What are your typical production lead times and delivery capabilities?

A: Standard replacement pumps and modular components are kept in stock for fast dispatch within several business days. Customized OEM batch orders typically ship within 3 to 4 weeks depending on batch volume and specialized tooling requirements. Exact delivery timelines are confirmed upon quotation.