A2FM107/61W-VAB010 A2FM63/61W-VAB020 A2FM63/61W-VAB027-Y Rexroth Piston Motor

Product Overview

The A2FM series bent-axis fixed displacement piston motors are a flagship product line within the Bosch Rexroth hydraulic transmission platform, classified as all-purpose high-pressure motors. Featuring a bent-axis design with axial tapered piston rotary groups, these motors are specifically engineered for hydrostatic drives in both open and closed circuits. Designed to fully comply with Rexroth A2FM Series 61 mounting and interface standards, these motors offer 100% direct interchangeability with original Rexroth units—enabling plug-and-play replacement without any管路 modifications or adapter plates, significantly minimizing downtime and retrofit costs.

The A2FM series covers an ultra-wide displacement range from 5 to 1000 cc/rev, with sizes 10–200 rated at 400 bar nominal pressure and 450 bar peak pressure. The 40° bent-axis design delivers exceptional power density, very high total efficiency, and outstanding starting efficiency. Every unit undergoes 100% factory testing under simulated real-world working conditions, validating pressure, flow, and sealing performance before shipment—ensuring reliable operation from the very first start.

Model Code Interpretation:

A2FM107/61W-VAB010 (Part No.: R902137953 / R902230003)

• A2FM – Series code: Bent-axis fixed displacement piston motor

• 107 – Displacement size: 106.7 cm³/rev

• 61 – Series number: Series 61

• W – Rotation: Bidirectional (viewed on drive shaft)

• VAB010 – Specific configuration code

A2FM63/61W-VAB020 (Part No.: R902230038 / R992001357 / R902186118)

• A2FM – Series code: Bent-axis fixed displacement piston motor

• 63 – Displacement size: 63 cm³/rev

• 61 – Series number: Series 61

• W – Rotation: Bidirectional (viewed on drive shaft)

• VAB020 – Specific configuration code (SAE working ports, etc.)

A2FM63/61W-VAB027-Y (Part No.: R902155634)

• A2FM – Series code: Bent-axis fixed displacement piston motor

• 63 – Displacement size: 63 cm³/rev

• 61 – Series number: Series 61

• W – Rotation: Bidirectional

• VAB027-Y – Specific configuration code

Technical Specifications 

A2FM107/61W-VAB010

• Model: A2FM107/61W-VAB010

• Part Number: R902137953 / R902230003

• Type: Bent-axis fixed displacement piston motor (Series 61)

• Geometric Displacement: 106.7 cm³/rev

• Nominal Pressure: 400 bar

• Maximum Pressure: 450 bar

• Maximum Speed: 2500 r/min

• Net Weight: 32.5 kg

• Rotation: Bidirectional (viewed on drive shaft)

• Design: 40° bent-axis

• Mounting Flange: ISO 3019-2 standard

• Medium: Mineral oil, synthetic hydraulic oil (HFB/HFC)

• Operating Temperature Range: -20°C to +80°C

• Seal Material: FKM (fluoroelastomer)

• Circuits: Open and closed circuits

A2FM63/61W-VAB020

• Model: A2FM63/61W-VAB020

• Part Number: R902230038 / R992001357 / R902186118

• Type: Bent-axis fixed displacement piston motor (Series 61)

• Geometric Displacement: 63 cm³/rev

• Nominal Pressure: 400 bar

• Maximum Pressure: 450 bar

• Maximum Speed: Approx. 3000 r/min (varies by configuration)

• Rotation: Bidirectional (viewed on drive shaft)

• Mounting Flange: ISO 3019-2 4-hole flange

• Drive Shaft: Splined shaft DIN 5480

• Port Configuration: SAE working ports A and B at side, opposite

• Seal Material: FKM (fluoroelastomer)

• Medium: Mineral oil, synthetic hydraulic oil (HFB/HFC)

• Circuits: Open and closed circuits

• Weight: Approx. 28 kg

A2FM63/61W-VAB027-Y

• Model: A2FM63/61W-VAB027-Y

• Part Number: R902155634

• Type: Bent-axis fixed displacement piston motor (Series 61)

• Geometric Displacement: 63 cm³/rev

• Nominal Pressure: 400 bar

• Maximum Pressure: 450 bar

• Rotation: Bidirectional

• Design: Bent-axis

• Medium: Mineral oil, synthetic hydraulic oil

• Circuits: Open and closed circuits

A2FM Series General Parameters:

• Displacement Range: 5–1000 cc/rev

• Sizes 10–200: Nominal pressure 400 bar / Peak pressure 450 bar

• Circuits: Open and closed circuits

• Design: Bent-axis, 40° bent-axis design

• Seal Material: FKM (fluoroelastomer)

• Mounting: ISO 3019-2 standard flange mounting

Key Technical Advantages

1. 100% Direct Interchangeability – Zero Modification Required

The A2FM series is engineered to exact Rexroth A2FM Series 61 mounting and interface specifications, with identical dimensions, port locations, and shaft end configurations. End users can replace original units directly without any管路 modifications or adapter plates—transforming unplanned downtime into scheduled, rapid maintenance while significantly reducing spare parts procurement costs and equipment downtime losses.

2. 40° Bent-Axis Design – High Power Density and Superior Efficiency

The 40° bent-axis design with axial tapered piston rotary groups delivers exceptional power density within a compact footprint. Very high total efficiency and outstanding starting efficiency make it critical for operations requiring immediate response. The bent-axis compact design ensures minimal friction losses and superior mechanical efficiency.

3. High-Pressure Capability with Wide Displacement Selection

Rated at 400 bar nominal pressure with 450 bar peak pressure, these motors maintain superior performance under high-load conditions. The A2FM series offers an ultra-wide displacement selection from 5 to 1000 cc/rev, allowing precise matching to specific application requirements.

4. Bidirectional Rotation with Flexible Configuration

Bidirectional rotation design (viewed on drive shaft) enables adaptation to various system requirements without the need for model changes based on rotation direction. Mounting flanges comply with ISO 3019-2 standards, and ports are compatible with SAE universal interfaces, enabling direct gearbox connection with high integration and easy installation.

5. Spherical Port Plate Technology – Self-Centering with Long Service Life

The cylinder block and port plate employ a spherical port plate design that automatically self-centers during rotation, reducing friction losses and enhancing efficiency. Reinforced bearings and wear-resistant friction pairs provide excellent shock and contamination resistance, operating within a -20°C to +80°C temperature range. Optional integrated pressure relief valves, counterbalance valves (BVD/BVE), flushing valves, and boost-pressure valves are available.

6. 100% Factory Testing Under Simulated Working Conditions

Every A2FM series unit undergoes rigorous factory testing under simulated real-world conditions, validating pressure, flow, volumetric efficiency, and sealing performance across the full operating range. Test media match actual operating conditions, ensuring each unit is ready for immediate installation and reliable operation upon delivery—eliminating the risk of “dead on arrival” components.

Application Areas

The A2FM series fixed displacement motors are widely deployed across the following industries and equipment types:

• Construction Machinery: Excavator travel/swing drives, rotary drilling rig power heads

• Road Construction Equipment: Roller travel drives, asphalt pavers

• Crane Machinery: Crane hoisting mechanisms, swing mechanisms

• Mining Equipment: Mining machinery, rock drilling rigs

• Metallurgical Industry: Rolling mill hydraulic stations, forging equipment

• Marine & Shipbuilding: Marine winches, deck machinery

• Agricultural Machinery: Large tractors, combine harvesters

• Industrial Equipment: Injection molding machines, conveyors

Specific model applications include:

• A2FM107/61W-VAB010: Medium excavator travel drives, rotary drilling rig power heads, bulldozer hydraulic systems

• A2FM63/61W-VAB020: Medium/small construction machinery travel/swing drives

• A2FM63/61W-VAB027-Y: Roller travel drives, industrial equipment hydraulic systems

Expert Maintenance Tips

1. Hydraulic Fluid Cleanliness Management

The A2FM series utilizes bent-axis piston designs with minimal clearances between pistons and cylinder bores, making them highly sensitive to fluid contamination. It is recommended to install filters with ≤10μm filtration rating, maintaining fluid cleanliness to ISO 4406 19/17/14 or better. Mineral oil or synthetic hydraulic oil (HFB/HFC) is recommended. Never use degraded or substandard hydraulic fluids.

2. Case Drain and Backpressure Control

Ensure the case drain line is unrestricted with no flow restrictions. For sizes 10–200, continuous case backpressure must not exceed 10 bar. Excessive case backpressure will cause shaft seal damage and premature bearing failure. The drain line should return directly to the reservoir, not in parallel with the return line.

3. Air Bleeding and Pre-filling Before Start-up

Always bleed air from the motor housing via the highest vent port before initial start-up or after extended shutdown periods to prevent cavitation damage. Ensure the motor housing is completely filled with hydraulic fluid prior to starting.

4. Coupling Alignment Requirements

Maintain shaft alignment within 0.05 mm concentricity and 0.5° angular deviation between the drive shaft and the load shaft. Excessive misalignment will lead to premature bearing wear and shaft seal leakage. The use of flexible couplings is recommended to compensate for minor installation deviations.

5. Rotation Direction Confirmation

The A2FM series features bidirectional rotation as viewed on the drive shaft. Verify that the system circuit direction matches the required rotation direction before installation—reversing fluid flow will reverse the motor’s direction of rotation.

6. Periodic Inspection and Maintenance

Inspect shaft seals for leakage and listen for abnormal operating noise every 1,000 operating hours or every 6 months (whichever comes first). Operating noise is typically ≤70dB(A). If reduced volumetric efficiency or insufficient output torque is observed, timely overhaul of the piston assembly and valve plate is recommended.