A2FM16/61W-VBB040 Rexroth Hydraulic Motor 16cc 400 bar

Product Overview

The A2FM16/61W-VBB040 is a bent-axis axial piston fixed displacement motor built on the Bosch Rexroth A2FM Series 61 platform, in the A2FM16 displacement size (16 cm³/rev). The motor features a bent-axis design with axial tapered piston rotary group, engineered for hydrostatic drives in both open and closed circuits. It offers a nominal pressure of 400 bar, peak pressure of 450 bar, maximum speed of 8,000 rpm, maximum input flow of 128 L/min, and theoretical torque of 102 N·m at nominal pressure.

The A2FM series employs a bent-axis design where pistons are arranged at an angle to the drive shaft and rest directly on the drive shaft to generate torque. The one-piece tapered piston with piston rings ensures reliable sealing, reducing internal leakage and improving volumetric efficiency. The series offers finely graduated displacement sizes from 5 to 1000 cm³/rev, enabling precise adjustment to specific application requirements.

The model code A2FM16/61W-VBB040 decodes as follows: A2FM designates the bent-axis fixed motor series, 16 is the displacement size (16 cm³/rev), 61 is the series designation (Series 61), W indicates bidirectional rotation, and VBB040 is the combination code for mounting flange, port configuration, and shaft type. The motor’s fixed displacement design eliminates the need for variable adjustment mechanisms, offering simple construction, low failure rate, and low maintenance requirements.

Engineered as a form-fit-function replacement for original Bosch Rexroth A2FM16 series motors, this model maintains identical mounting flange dimensions (ISO 3019-2 four-hole flange), shaft specifications (DIN 5480 splined shaft), and port locations, enabling drop-in interchangeability without modification to the host machine’s mounting interface or hydraulic circuit. Each unit undergoes 100% simulated load testing prior to shipment, validating output torque and volumetric efficiency against original specifications.

Technical Specifications 

• Model: A2FM16/61W-VBB040

• Material Number: R902196980

• Series: Bosch Rexroth A2FM Series 61

• Motor Type: Bent-axis axial piston fixed displacement motor

• Design Feature: Bent-axis configuration, axial tapered piston rotary group, one-piece tapered piston with piston rings

• Displacement (Vg): 16 cm³/rev

• Nominal Pressure (p nom): 400 bar (40 MPa / 5,800 psi)

• Peak Pressure (p max): 450 bar (45 MPa / 6,525 psi)

• Maximum Speed (n max): 8,000 rpm

• Maximum Input Flow (qV max): 128 L/min

• Theoretical Torque at p nom: 102 N·m

• Theoretical Torque at 350 bar: 89 N·m

• Rotation: Bidirectional (W)

• Mounting: ISO 3019-2 four-hole flange

• Shaft Type: DIN 5480 splined shaft

• Seal Material: FKM

• Working Ports: SAE flange or thread

• Weight (approx.): 5.4 kg (11.9 lb)

• Moment of Inertia (Rotary Group): 0.0004 kg·m²

• Circuit: Open circuit / Closed circuit

• Optional Features: Integrated pressure relief valve, counterbalance valve (BVD/BVE), flushing and boost-pressure valve

Key Technical Advantages

1. Bent-Axis Tapered Piston Design with High Mechanical Efficiency

The A2FM16/61W-VBB040 employs the classic bent-axis design of the Bosch Rexroth A2FM series, where pistons are arranged at an angle to the drive shaft and rest directly on the drive shaft to generate torque.Compared to swashplate designs, the bent-axis configuration reduces friction losses between pistons and the drive plate, achieving mechanical efficiency of 94–96%—3 to 5 percentage points higher than comparable swashplate motors.The one-piece tapered piston with piston rings ensures reliable sealing, reducing internal leakage and improving volumetric efficiency.

2. High Power Density with Compact Construction

The A2FM16 achieves a displacement of 16 cm³/rev, nominal pressure of 400 bar, and maximum input flow of 128 L/min at a weight of only 5.4 kg, offering an exceptionally high power-to-weight ratio. The bent-axis design achieves high power density within a compact envelope, suitable for mobile hydraulic systems with limited installation space.Finely graduated displacement sizes (5 to 1000 cm³/rev) enable precise adjustment of the same series to specific applications, simplifying system selection and integration.

3. High-Speed Capability with Excellent Starting Efficiency

The A2FM16 reaches a maximum speed of 8,000 rpm, suitable for applications requiring high-speed output. The A2FM series features excellent starting efficiency and high total efficiency, with no significant difference between starting torque and running torque, maintaining stable torque output during low-speed starts and heavy-load conditions. Output speed is proportional to pump flow and motor displacement, while output torque increases with the pressure differential between high and low-pressure sides.

4. Multi-Standard Mounting Compatibility with Functional Extensibility

The A2FM series motor’s mounting flange conforms to ISO 3019-2 standard (four-hole flange), with DIN 5480 splined shaft configuration, SAE flange or threaded working ports, and FKM fluorocarbon seals suitable for high-temperature and chemically aggressive media.The motor can be optionally equipped with an integrated pressure relief valve for additional safety protection. Counterbalance valves (BVD/BVE), flushing valves, and boost-pressure valves can also be mounted directly onto the motor, simplifying system piping design and reducing external connection points and leakage risks.

Application Areas

• Construction Machinery: Excavator travel drives, wheel loader travel drives, roller travel drives

• Agricultural Machinery: Combine harvester travel drives, self-propelled sprayers

• Mining Equipment: Mining truck travel drives, underground transport equipment

• Material Handling: Forklift drives, reach stacker travel systems

• Industrial Drives: Closed-circuit hydrostatic transmission systems, winch drives

• Specialty Vehicles: Concrete mixer truck drives, municipal service vehicles

Expert Maintenance Tips

1. Shaft Alignment Requirements: During installation, ensure the coaxiality deviation between the motor shaft and drive-end spline does not exceed 0.05 mm. The bent-axis motor’s tapered piston rotary group is sensitive to radial forces; excessive radial forces will accelerate wear on the piston tapered surfaces and drive plate, degrading volumetric efficiency.

2. Hydraulic Fluid Cleanliness Control: The A2FM series motor features precision clearances in the piston and distribution pairs. Maintain hydraulic fluid cleanliness at ISO 20/18/13 or better. Replace hydraulic fluid and filter elements every 1,000 operating hours or annually, with filter element filtration accuracy no less than 10 μm.

3. Viscosity and Temperature Management: The optimum viscosity range is 16–36 mm²/s. Hydraulic fluid temperature should not exceed +115°C during continuous duty. If external housing temperature rises abnormally, check for system pressure overload or sudden increases in case drain leakage.

4. Initial Startup Preparation: Fill the motor housing with clean hydraulic fluid during initial installation to prevent dry friction on piston pairs during startup. The drain port must be connected separately to the reservoir with back pressure not exceeding 0.5 MPa.

5. Restart After Extended Storage: For motors stored over 6 months, manually rotate the shaft 2–3 revolutions to confirm free rotation, then run at low pressure (10 MPa) under no load for 10 minutes, confirming normal case temperature and leakage before gradually applying load.