Product Overview
The A2FM80/61W-VBB010 is a Bosch Rexroth A2FM Series bent-axis axial piston fixed displacement motor with a displacement of 80.4 cm³/rev, belonging to the Series 61 high-pressure open/closed circuit family. Featuring a 40° bent-axis design with tapered piston rotary group, it operates at a nominal pressure of 400 bar and can withstand peak pressures up to 450 bar, delivering exceptional power density and compact construction for mobile and industrial hydraulic drive systems. The series also includes the A2FM90/61W-VBB010-H (90 cm³) and A2FM107/61W (106.7 cm³) frame sizes.
Manufactured to original Bosch Rexroth specifications with guaranteed drop-in interchangeability, this motor directly replaces the OEM A2FM series motor without modification to mounting interfaces or hydraulic plumbing. Critical rotating components — including the cylinder block, tapered pistons, valve plate, and drive shaft — are precision-machined to OEM tolerances. The mounting flange, spline configuration, and port locations are identical to the original. Every unit undergoes 100% simulated working-condition dyno testing prior to shipment, including rated pressure cycling, torque output verification, and leakage inspection, ensuring volumetric efficiency, mechanical efficiency, and starting characteristics meet OEM-equivalent standards.
Technical Specifications
A2FM80/61W-VBB010 Primary Parameters:
Model: A2FM80/61W-VBB010
OEM Material #: R902138457
Series: Rexroth A2FM Series 61
Type: Bent-axis axial piston fixed displacement motor (open/closed circuit)
Displacement: 80.4 cm³/rev
Nominal Pressure: 400 bar
Maximum Pressure: 450 bar
Maximum Speed (nmax): 4,500 rpm
Maximum Flow (at nmax): 360 L/min
Maximum Torque (Δp=400 bar): 508 N·m
Direction of Rotation: Bidirectional (W = bidirectional)
Weight: Approx. 23 kg
A2FM90/61W-VBB010-H Primary Parameters:
Model: A2FM90/61W-VBB010-H
Series: Rexroth A2FM Series 61
Displacement: 90 cm³/rev
Nominal Pressure: 400 bar
Maximum Pressure: 450 bar
Maximum Speed (nmax): 4,500 rpm
Maximum Flow (at nmax): 405 L/min
Maximum Torque (Δp=400 bar): 572 N·m
Weight: Approx. 23 kg
A2FM107/61W-VZB027 Primary Parameters:
Model: A2FM107/61W-VZB027
OEM Material #: R902137953
Series: Rexroth A2FM Series 61
Displacement: 106.7 cm³/rev
Nominal Pressure: 400 bar
Maximum Pressure: 450 bar
Maximum Speed (nmax): 4,000 rpm
Maximum Flow (at nmax): 427 L/min
Maximum Torque (Δp=400 bar): 680 N·m
Weight: Approx. 32.5 kg
A2FM Series 61 Common Specifications:
Mounting: SAE standard flange (metric version)
Working Ports: SAE flange or threaded port options
Shaft: Tapered shaft with threaded pin and Woodruff key (DIN 6888)
Optional Valves: Integrated pressure relief valve, counterbalance valve (BVD/BVE), flushing and boost pressure valve
Bearing Options: Long-life bearings available (sizes 250–1000)
Hydraulic Fluid: Mineral-based hydraulic oil (ISO VG 32–68)
Filtration: ISO 4406 cleanliness level 20/18/15 or better
Key Technical Advantages
1. 40° Bent-Axis Tapered Piston Design with High Starting Efficiency
The A2FM series utilizes a 40° bent-axis design with tapered pistons and piston ring sealing. Output torque increases linearly with the pressure differential between high and low pressure sides and with increasing displacement. This design enables the motor to establish a stable hydrodynamic lubrication film immediately upon start-up, delivering excellent starting efficiency — particularly suited for drive systems requiring frequent start-stop cycles or loaded starts. The tapered piston sealing method accommodates high pressure differential conditions better than conventional slipper-type designs, effectively reducing internal leakage.
2. High Power Density with Compact Lightweight Construction
The A2FM80 delivers 508 N·m of torque at 400 bar nominal pressure while weighing only approximately 23 kg. The Series 61 design is more compact than the previous generation, and with high power density, it transmits greater power within a limited installation envelope. The A2FM series offers finely graduated displacements from 5 to 1000 cm³/rev, allowing precise matching of drive system parameters to specific application requirements.
3. Integrated Valve Options with Modular Expansion
A2FM series motors support direct mounting of various functional valves on the housing, including counterbalance valves (BVD/BVE), flushing and boost pressure valves, and an optional integrated pressure relief valve. These valves connect to the motor housing through standardized interfaces without additional piping or mounting brackets, significantly simplifying system layout. The modular design also allows the motor to be used as a pump in closed circuits, increasing application flexibility.
4. Precision Valve Plate and Low-Noise Operation
The valve plate flow passages are hydrodynamically optimized to effectively reduce pressure loss and flow pulsation during the porting cycle, ensuring smooth operation even at the maximum speed of 4,500 rpm. Cylinder bores are precision-honed with micron-level clearances, ensuring volumetric efficiency across the full pressure range. The housing is cast from high-strength iron, balancing structural rigidity with lightweight requirements.
Application Areas
The A2FM80/61W-VBB010, A2FM90/61W-VBB010-H, and A2FM107/61W are widely used in the following equipment:
Concrete mixer truck drum drive systems
Excavator swing and travel drive circuits
Vibratory roller propel drives
Rotary drilling rig power head drives
Marine hydraulic winches and deck machinery
Agricultural machinery hydraulic drive systems
Industrial hydraulic power units (coilers, levelers, etc.)
Lifting and transport equipment travel and winch circuits
Expert Maintenance Tips
Pre-Installation Checks: Verify that the motor shaft configuration (spline or tapered shaft per DIN 6888) matches the drive end before installation. For tapered shaft connections, torque must be transmitted through the tapered press fit; tighten fixing bolts to the specified torque values to ensure full taper contact. Apply a light coating of grease to spline surfaces. Ensure full contact between the mounting flange and the mounting pad. Never force the motor into position by tightening the fixing bolts.
Oil Cleanliness Control: A2FM series motors are sensitive to fluid contamination. System oil cleanliness should be maintained at ISO 4406 level 20/18/15 or better. Under high-pressure operating conditions (above 400 bar), a cleanliness level of 19/17/14 is recommended. Suction filters should be rated at 10 μm or finer; return-line filters at 10 μm or finer are recommended. Check suction line sealing before first start-up to prevent air ingress and cavitation.
Case Drain Management: The case drain line must remain unrestricted; case pressure must not exceed 2 bar (gauge). Route the drain line directly to the reservoir below the oil level to avoid backpressure affecting motor operation. In multi-motor series installations or where long case drain lines are required, pay special attention to return backpressure — a separate drain line may be necessary.
Start-Up and Break-In: During initial start-up, operate at low speed and low pressure for 10–15 minutes to purge air from the system and check all connections for leakage. Fill the motor case with clean hydraulic oil through the case drain port before starting to prevent dry-start damage to the rotary group. If the motor has been stored for an extended period, repeat these steps upon recommissioning.
Routine Maintenance: Periodically check fluid level and contamination levels; replace hydraulic oil and filter elements at recommended intervals. Monitor motor noise and vibration during operation. If abnormal noise, reduced output torque, or excessive case temperature is observed, stop the machine immediately and investigate. Setting values of integrated valves (such as counterbalance or flushing valves) should not be adjusted arbitrarily — refer to the original Rexroth technical manual if adjustment is required.
