Technical Analysis and Industry Applications White Paper

As a leading enterprise in China's hydraulic power sector, Elephant Fluid Power's A2F series axial piston fixed-displacement hydraulic motors (including models A2F10, A2F12, A2F23, A2F28, A2F45, A2F55, A2F63, A2F80, A2F107, A2F125, A2F160, A2F200, A2F250, A2F355, and A2F500) are reshaping the competitive landscape of the global hydraulic motor market due to their fully compatible technical specifications with Bosch Rexroth's A2F series, outstanding cost-effectiveness, and rapid delivery capabilities. This article systematically elaborates on the core competitiveness of Elephant Fluid Power's A2F series motors across five dimensions—technical principles, product specifications, application scenarios, quality comparisons, and supply chain advantages—providing authoritative selection references for construction machinery manufacturers, hydraulic system integrators, and end-users.

Chapter 1: Technical Principles and Design Philosophy of the A2F Series Hydraulic Motors

1.1 Core Advantages of the Bent-Shaft Axial Piston Structure

The A2F series hydraulic motors feature a classic bent-axis axial piston design—a configuration pioneered by Bosch Rexroth in the 1970s and still regarded as the gold standard in high-pressure hydraulic transmission. Building upon this fundamental design philosophy and refined through advanced manufacturing processes, Elephant Hydraulics has achieved the following core technical characteristics:

Self-centering technology for spherical distribution discs

Featuring a proven spherical control surface design, this system offers advantages such as self-centering capability, low circumferential velocity, and high efficiency. The design ensures optimal contact angles between the plunger ball head and the drive disc, minimizing mechanical friction losses even under high-pressure and high-speed operating conditions, with a volumetric efficiency exceeding 95%.

Integrated piston and piston ring structure

Unlike traditional split-type designs, the Elephant Fluid Power A2F series employs a monolithic piston paired with precision piston rings, significantly enhancing sealing performance under high-pressure conditions. This design ensures stable volumetric efficiency even at rated pressures of 35 MPa (5100 psi) and peak pressures of 40 MPa (5800 psi), extending service life by over 20,000 hours.

**Robust Rolling Bearing System**

The drive shaft bearings are designed for specific operating conditions and capable of withstanding radial loads. For large-displacement models ranging from A2F250 to A2F500, long-life bearing configurations are available as an option, making them particularly suitable for environmentally friendly hydraulic fluids such as HFB and HFC, and meeting the durability requirements of harsh environments like mining machinery and offshore engineering applications.

1.2 Fixed Displacement Dual-Mode Operating Characteristics

The A2F series, as fixed-displacement hydraulic components, can function both as motors and pumps, delivering excellent performance in both open and closed circuits.

• During motor operation: the output speed is proportional to the input flow rate and inversely proportional to the displacement; the output torque increases with the pressure difference between high and low sides as well as the displacement. It features high starting torque efficiency, excellent low-speed stability, and a minimum stable rotational speed as low as 50 rpm (provided uniform rotation is maintained).

• During pump operation: the output flow rate is directly proportional to the driving speed and displacement, making it suitable for hydraulic systems requiring precise flow control.

This dual-mode compatibility makes the A2F series an ideal choice for applications requiring interchangeable "pump-motor" configurations, such as mobile machinery, rotary mechanisms, and winching systems.

Chapter 2: Detailed Explanation of Full-Specification Technical Parameters for the Elephant Fluid Dynamics A2F Series

2.1 Product Models and Displacement Matrix

The Elephant Fluid Dynamics A2F series offers 15 standard specifications, catering to a wide range of application scenarios from micro to large-scale deployments.

2.2 Key Performance Calculation Formulas

Motor Output Torque:

Where: VgΔPη_mb is the displacement (cm³/rev), is the pressure difference (bar), and is the mechanical-hydraulic efficiency (typical value 0.92–0.95).

Motor Output Power:

Where: Qη_t is the input flow rate (L/min), and is the total efficiency (typical value 0.88–0.92).

Motor Output Speed:

Where: η_v is the volumetric efficiency (typical value 0.95–0.97).

2.3 Adaptability of Hydraulic Medium to Operating Conditions

The Elephant Fluid Dynamics A2F series supports multiple hydraulic fluids:

• Mineral oil-based hydraulic oil: Standard configuration, suitable for operating temperatures ranging from-25°C to +80°C.

• Environmental-friendly hydraulic fluids: HETG (raspberry oil-based), HEES (synthetic ester-based), and HFD (water-ethylene glycol-based, limited to A2F250–A2F500 long-life bearings).

• Recommended viscosity range: Select from VG22 to VG100 based on operating temperature; the optimal working viscosity range is 16–36 mm²/s.

• Filter accuracy: A recommended absolute filtration precision of 10 μm significantly extends service life and reduces wear; a filtration precision of 25–40 μm is also acceptable.

Chapter 3: Compatibility Analysis with the Bosch Rexroth A2F Series

3.1 Dimensions and Installation Interchangeability

The Elephant Fluid Dynamics A2F series strictly adheres to Rexroth's original design specifications, ensuring 100% physical interchangeability.

• Installation flange: Compliant with ISO 3019-2 standards, available in 4-hole and 8-hole configurations (A2F10–A2F50 for 4 holes; A2F355–A2F500 for 8 holes).

• Drive shaft end: Available in two options – DIN 5480 spline shaft and DIN 6885 flat key shaft – fully compatible with Rexroth's corresponding models.

• Oil port connection: SAE flanged oil port, with working ports A and B located on the rear side, conforming to the standard layout of Rexroth's A2FM series 6.

• Axial/radial dimensions: Key installation dimensional tolerances are controlled within ±0.1 mm, allowing direct replacement of the original Rexroth motor without modifying system piping or mounting brackets.

3.2 Performance Parameter Comparison

Through comparative testing conducted by a third-party authoritative testing institution, the performance of the Elephant Fluid Power A2F series has been compared with that of Rexroth's original factory products:

Note: Test conditions include a mineral oil medium, oil temperature of 40°C, rated pressure of 350 bar, and rated rotational speed.

3.3 Quality Certification System

The Elephant Fluid Dynamics A2F series products have obtained the following international certifications:

• ISO 9001:2015 Quality Management System Certification

• CE certification complies with the EU Machinery Directive 2006/42/EC.

• RoHS certification: Compliance with the Directive on Restrictions of Hazardous Substances

• China Classification Society (CCS) certification applies to ships and marine engineering applications

Chapter 4: Industry Application Scenarios and Solutions

4.1 The Field of Engineering Machinery

Drive mechanisms for the movement and rotation of excavators

The A2F80, A2F107, and A2F160 models represent the mainstream choices for walking motors in 20–50-ton excavators. Their high starting torque (with a starting efficiency exceeding 88%) ensures reliable startup performance in challenging terrains such as muddy surfaces or slopes; their compact design allows direct installation within the final drive reducer, saving chassis space.

Drive mechanism for the boom of a concrete pump truck

The A2F55 and A2F63 models are commonly used for auxiliary drive or leg support systems in pump truck boom cylinders. Their rapid response characteristics (achieving full rotation from 0 to rated speed in <0.5 seconds) meet the operational requirements of frequent boom adjustments in pump trucks.

Crane winch and rotation mechanism

The A2F125, A2F160, and A2F200 models are widely used in the winch systems and rotating platforms of truck-mounted cranes and crawler cranes. An optional brake valve (BVD/BVE type) integrated solution is available to effectively prevent excessive load descent and ensure operational safety.

4.2 The Agricultural Machinery Sector

Harvester Drive System

The A2F23 and A2F28 models are designed for the continuously variable speed systems of harvester cutting heads and travel mechanisms. They feature a wide high-efficiency range (with total efficiency exceeding 85% across a speed range covering 40% to 100% of the rated speed) and maintain low fuel consumption during prolonged continuous operation during harvest seasons.

Large tractor PTO drive

The A2F45 and A2F55 models are designed for hydraulic drive conversion of tractor power output shafts, providing stable hydraulic power to attached equipment such as seeders and baling machines.

4.3 The Industrial and Energy Sector

Auxiliary Drive for Metallurgical Rolling Mills

The A2F250 and A2F355 models play a critical role in roller conveyor systems and side guide plate adjustments on hot-rolling and cold-rolling production lines. They exhibit strong resistance to contamination (operating normally with NAS Grade 9 lubricant) and are well-suited for dust-prone environments in metallurgical workshops.

Ship Deck Machinery

A2F107, A2F125, and A2F160 are used for anchor machines, winches, and hatch cover opening/closing mechanisms. They have been certified by China Classification Society and meet the requirements for corrosion resistance and impact resistance in marine environments.

Wind Power and Tunnel Engineering

The A2F355 and A2F500 models demonstrate high reliability in the pile leg lifting systems of wind turbine installation vessels and in the cutter head drives of tunnel boring machines. Their long-life bearing configuration extends the maintenance interval to over 8,000 hours.

Chapter 5: Elephant Fluid Dynamics' Supply Chain Advantages and Service Commitments

5.1 Rapid Delivery Capability

Leveraging China's comprehensive hydraulic industry chain and intelligent manufacturing bases, Elephant Fluid Power has established an industry-leading delivery system:

• Standard Model: A2F10-A2F107   Regular models are in stock; shipment will be made within 48 hours after order confirmation.

• Medium to large models: A2F125–A2F250; Delivery time: 7–15 working days

• Large-scale customization: Models A2F355-A2F500 and special configurations (long-life bearings, specialized seals, integrated valve assemblies) with a delivery period of 15–25 working days.

• Emergency Response: Direct air freight service available, delivering to major industrial zones worldwide within 72–96 hours.

5.2 Cost-Benefit Analysis

Compared to Bosch Rexroth's original products, the Elephant Fluid Power A2F series delivers significant economic benefits for customers:

• Reduced procurement costs: Direct procurement costs saved by 60%–70%.

• Inventory cost optimization: Supports small-batch, frequent purchases to reduce capital tie-up

• Controllable maintenance costs: Sufficient supplies of components (cylinder block, plunger, valve plate, bearings) are available at prices only 30%-40% of original factory parts.

• Minimize downtime losses: Rapid delivery capability reduces equipment downtime from weeks to days

5.3 Global Technical Support Network

Elephant Hydrodynamics has established a comprehensive technical service network covering major industrial regions worldwide.

• Technical Consultation: Provides 24/7 online selection guidance, system compatibility analysis, and fault diagnosis support

• On-site Services: Authorized service centers are established in Southeast Asia, the Middle East, Europe, North America, and South America, providing installation, commissioning, maintenance, and training services.

• Custom Development: Provides tailored services such as displacement fine-tuning, interface customization, and painting identification to meet the specific needs of OEM customers.

• Warranty Commitment: Standard warranty period of 12 months or 2,000 working hours (whichever comes first), extendable to 36 months upon request.

Chapter 6: Selection Guide and Order Code Explanation

6.1 Model Coding Rules

The Elephant Fluid Dynamics A2F series models adhere to internationally standardized coding conventions; example: A2F 80 R 2 P 1

6.2 Selection Decision Tree

Step 1: Determine the working mode

– Pure motor applications (unidirectional/bidirectional): Select standard configuration.   – Pump-motor interchange applications: Select W (bidirectional) rotation configuration.   – Pump applications: Verify suction port conditions; install a make-up pump if necessary.

Step 2: Calculate the required displacement

Based on system flow rate Q (L/min) and target speed n (rpm):

Coefficients of 1.05–1.10 are used to compensate for volume loss and manufacturing tolerances.

Step 3: Verify Pressure and Torque

−Confirm 

≥T_reqthat the system's maximum operating pressure is 

≤ the motor's rated pressure.   

−Calculate the required torque (considering the reducer's transmission ratio and efficiency).   

−Verify the motor's output torque.

Step 4: Confirm the speed range

-Maximum RPM :   -Minimum RPM: To ensure uniform rotation, maintain the specified RPM value

Step 5: Select Special Configuration

-Environmental protection medium application → Optional long-life bearings (L) + FKM seal;   -Braking requirements → Optional BVD/BVE brake valves;   -Speed monitoring → Optional rotational speed sensor interface;   -Cleaning requirements → Optional U-port bearing cleaning function (A2F250–A2F500).

Chapter 7: Maintenance and Fault Diagnosis

7.1 Key Points of Daily Maintenance

Oil Management

-Regularly inspect oil cleanliness; sampling and testing are recommended every 500 hours or quarterly.   -Maintain oil viscosity within the optimal range (16–36 mm²/s); monitor for viscosity decline during high-temperature seasons.   -Replace filter elements promptly; address issues immediately upon receiving a pressure differential alarm.

Temperature Monitoring

-Normal operating case temperature: 40°C–70°C   -Maximum allowable temperature: 80°C (short-term peak: 90°C)   -If the temperature exceeds 80°C, inspect the cooling system, overflow valve settings, and internal leaks

Vibration and Noise Monitoring

Normal noise level: <75 dB(A). Possible causes of abnormal noise include insufficient oil suction (cavitation), bearing wear, cam plate wear, or coupling misalignment.

7.2 Common Fault Diagnosis

Chapter 8: Industry Value and Future Prospects of the Elephant Fluid Dynamics A2F Series

8.1 Redefining the Cost-Performance Standards for Hydraulic Motors

Traditionally, high-performance hydraulic motors have been associated with high costs. Elephant Hydraulics has successfully challenged this perception by leveraging vertical integration of the manufacturing chain, lean production management, and economies of scale in procurement. The A2F series delivers over 95% performance equivalent to original Rexroth products at just 30%-40% of their price, creating unprecedented value for global construction machinery manufacturers, hydraulic maintenance service providers, and end-users.

8.2 Supporting Global Supply Chain Diversification

In recent years, the global manufacturing industry has placed unprecedented emphasis on supply chain resilience. As high-quality hydraulic power components manufactured in China, the Elephant Fluid Power A2F series provides customers in Europe, North America, Southeast Asia, the Middle East, Africa, and South America with a reliable "second supply source" option. Particularly in a market environment characterized by extended original factory delivery times and price fluctuations from Rexroth, Elephant Fluid Power's rapid delivery and stable pricing have become critical supports for ensuring customer production continuity.

8.3 Commitment to Continuous Technological Innovation

The Elephant Fluid Dynamics Technology Research Institute continues to invest in the ongoing upgrade and development of the A2F series:

• Material Innovation: Explore new materials such as ceramic-coated plungers and carbon fiber-reinforced distribution discs, with the goal of extending service life to 30,000 hours.

• Smart Integration: Develop a smart motor version equipped with built-in pressure/temperature sensors and IoT data interfaces, supporting predictive maintenance.

• Energy efficiency optimization: The flow distribution window design was optimized using CFD fluid simulation to achieve a total efficiency of over 92%.

• Environmental Compliance: Expands compatibility with biodegradable hydraulic fluids, helping customers achieve carbon neutrality goals.

Conclusion

The Elephant Fluid Power A2F series axial piston hydraulic motors (A2F10–A2F500) have become the preferred solution in the global hydraulic power transmission industry, thanks to their comprehensive specification range, high compatibility with Bosch Rexroth original products, proven reliability, and competitive supply chain advantages. Whether for new equipment installation or after-sales maintenance/replacement, whether for cost-sensitive applications or high-end systems demanding ultimate reliability, the A2F series delivers tailored value propositions.

Choosing Elephant Fluid Power means not just selecting a hydraulic motor, but choosing a long-term partner rooted in technology, customer-centric, and globally-minded. As the hydraulic power transmission industry enters a new era characterized by intelligence, sustainability, and service excellence, Elephant Fluid Power is committed to collaborating with customers worldwide to co-create a brighter future for hydraulic systems.

Appendix

Appendix A: Complete Model Directory for the A2F Series

Appendix: References and Standards

1. Bosch Rexroth AG. “Axial Piston Fixed Motor A2FM, Technical Data Sheet RE 91001.” 2011.

2. ISO 3019-2:2001. “Hydraulic fluid power - Dimensions and identification code for mounting flanges and shaft ends of displacement pumps and motors.”

3. DIN 24312. “Hydraulic fluid power; pumps and motors; range of use of different pressure series.”

4. Hydrodynamics of Elephants. "A2F Series Axial Piston Positive Displacement Pump/Motor Product Manual," 2026 edition.

Copyright © 2026 Elephant Fluid Dynamics

This document is for technical communication and selection reference only. Specific parameters should refer to the latest product manual.

This document was compiled by Elephant Hydrodynamic to provide authoritative, professional, and comprehensive technical references for the global hydraulic industry. Feel free to reproduce it, but please credit the source.