Product Overview
The A2F55W2P2 is a 55 cm³/rev displacement model from Bosch Rexroth’s A2F series of bent-axis axial tapered piston fixed displacement pumps/motors. The A2F series employs an axial tapered piston rotary group of bent-axis design with displacements ranging from 4.93 to 1000 cm³/rev, serving as Rexroth’s classic fixed displacement pump/motor dual-purpose platform operable as either pump or motor in open and closed circuits. The series is renowned for high power density, compact dimensions, high total efficiency and long service life.
The A2F55 mid-range displacement size balances torque output and flow demand, with 350 bar nominal pressure, 400 bar peak pressure, maximum speed up to 3500 rpm and weight of approximately 16–18 kg. The models listed on this page — A2F55W2P2, A2F55R2P3, A2F55W2Z2 — all belong to the A2F55 frame size, with primary differences in rotation direction code (R=clockwise, L=anti-clockwise, W=alternation/bidirectional), rear cover configuration code (2/3) and shaft end type (P=keyed shaft GB1096-79, Z=splined shaft DIN 5480). The A2F160W2P2, A2F125W2P2 and A2F63W2P2 listed on the same page belong to other displacement sizes in the same A2F series platform, sharing the same bent-axis rotary group technology.
Every A2F55W2P2 unit undergoes 100% simulated operating-condition bench testing prior to shipment, covering pressure cycling, speed stepping and volumetric efficiency verification. Mounting flange, shaft end and port dimensions comply with ISO/SAE standards and are identical to the original Rexroth A2F55 series, ensuring true drop-in interchangeability with zero modification required.
Technical Specifications
A2F Series Frame Size Specifications:
A2F10: Displacement 9.4 cm³/rev, nominal pressure 350 bar, peak pressure 400 bar, max speed 7500 rpm, max flow 71 L/min, weight ~5 kg
A2F12: Displacement 11.6 cm³/rev, nominal pressure 350 bar, peak pressure 400 bar, max speed 6000 rpm, max flow 70 L/min, weight ~5 kg
A2F23: Displacement 22.7 cm³/rev, nominal pressure 350 bar, peak pressure 400 bar, max speed 5600 rpm, max flow 127 L/min, weight ~12 kg
A2F28: Displacement 28.1 cm³/rev, nominal pressure 350 bar, peak pressure 400 bar, max speed 4750 rpm, max flow 133 L/min, weight ~12 kg
A2F45: Displacement 44.3 cm³/rev, nominal pressure 350 bar, peak pressure 400 bar, max speed 4500 rpm, max flow 199 L/min, weight ~23 kg
A2F55 (This Model): Displacement 54.8 cm³/rev, nominal pressure 350 bar (35 MPa), peak pressure 400 bar (40 MPa), max speed 3750 rpm, max flow 206 L/min, weight ~23–33 kg
A2F63: Displacement 63.0 cm³/rev, nominal pressure 350 bar, peak pressure 400 bar, max speed 4000 rpm, max flow 252 L/min, weight ~33 kg
A2F80: Displacement 80.0 cm³/rev, nominal pressure 350 bar, peak pressure 400 bar, max speed 3350 rpm, max flow 268 L/min, weight ~33 kg
A2F107: Displacement 107 cm³/rev, nominal pressure 350 bar, peak pressure 400 bar, max speed 3000 rpm, max flow 321 L/min, weight ~44 kg
A2F125: Displacement 125 cm³/rev, nominal pressure 350 bar, peak pressure 400 bar, max speed 3150 rpm, max flow 394 L/min, weight ~63 kg
A2F160: Displacement 160 cm³/rev, nominal pressure 350 bar, peak pressure 400 bar, max speed 3650 rpm, max flow 424 L/min, weight ~63 kg
A2F55W2P2 Additional Specifications:
Model Codes: A2F55W2P2, A2F55R2P3, A2F55W2Z2, A2F63W2P2, A2F125W2P2, A2F160W2P2
Type: Bent-axis axial tapered piston fixed displacement pump/motor
Displacement: 54.8 cm³/rev (3.34 in³/rev), fixed and non-adjustable
Nominal Pressure (Continuous): 350 bar (5,076 psi)
Peak Pressure (Intermittent): 400 bar (5,802 psi)
Rated Speed (n nom): 3000 rpm
Maximum Speed (n max): 3750 rpm
Limit Speed: 4500 rpm (open circuit)
Maximum Flow (at n max): 206 L/min
Torque (at Δp=350 bar): ~306 N·m
Rotation: Bidirectional (W = Alternation/Bidirectional)
Shaft Type: Keyed shaft (P = Keyed Shaft, GB1096-79)
Rear Cover Configuration: No. 2 rear cover
Mounting Flange: ISO standard flange (from size 55)
Port Connections: SAE flange ports
Hydraulic Fluid: Mineral oil (ISO VG46/68), synthetic oil, water glycol
Operating Temperature Range: -25°C to +80°C (not exceeding 90°C under load)
Optimal Operating Viscosity: 16–36 mm²/s, max allowable 1000 mm²/s, min allowable 10 mm²/s
Filtration Accuracy: Optimal 5–10 μm, minimum not exceeding 25 μm
Weight: ~23–33 kg (depending on configuration)
Original Design: Bosch Rexroth, Germany
Key Technical Advantages
1. Bent-Axis Tapered Piston Design for High Power Density and Total Efficiency
The A2F55W2P2 employs Rexroth’s signature bent-axis axial tapered piston rotary group design, with the cylinder block angled relative to the output shaft and tapered pistons transmitting force directly to the drive shaft through a thrust plate. The design features self-centering, low peripheral speed and high efficiency, with a high-performance rotary group featuring a well-proven spherical control area that effectively reduces internal leakage and friction losses. One-piece tapered pistons with piston rings maintain high volumetric and mechanical efficiency across the full speed and pressure range, with typical volumetric efficiency exceeding 95%.
2. High Pressure Capability — 350 Bar Nominal, 400 Bar Peak
The A2F55W2P2 supports 350 bar nominal working pressure and 400 bar maximum working pressure, with approximately 306 N·m torque at Δp=350 bar. This power density leads among comparable bent-axis pumps/motors, offering significant advantages in travel drive and tool drive applications requiring high torque density. Output torque increases with the pressure differential between high and low pressure sides, meeting the demands of various heavy-duty conditions.
3. Pump/Motor Dual-Purpose and Open/Closed Circuit Compatibility
As a member of the A2F series, the A2F55W2P2 can operate as either a pump or a motor, suitable for hydrostatic drives in open and closed circuits. When operated as a pump, flow is proportional to drive speed and displacement; when operated as a motor, output speed is proportional to flow and inversely proportional to displacement. This dual-purpose capability enables a single component to cover both pump drive and motor drive application requirements, significantly simplifying hydraulic system component selection and inventory management.
4. Robust Bearing Design and Radial Load Capability
Drive shaft bearings are designed for the bearing service life requirements usually encountered in these areas and are capable of adopting radial loading. Robust rolling bearings ensure long service life, and the drive shaft is capable of adopting radial loading, simplifying drivetrain design without additional bearing support mechanisms. The compact construction and lightweight design (approximately 23–33 kg) deliver excellent installation flexibility in space-constrained applications.
5. 100% Simulated Load Testing & Drop-In Interchangeability
Each A2F55W2P2 unit is bench-tested under simulated operating conditions prior to dispatch, covering pressure cycling, speed stepping and volumetric efficiency verification. Mounting flange, shaft end and port dimensions comply with ISO/SAE standards, matching the original Rexroth A2F55 series exactly, enabling direct replacement without any interface modification.
Application Areas
The A2F55W2P2 is deployed across demanding applications:
Construction: 6–12 ton excavator travel motors (Liebherr, Schaeff, O&K, Wacker Neuson, Bobcat, Atlas, Terex, Caterpillar, John Deere brands)
Road Rollers: medium-class road roller vibration motors
Concrete Machinery: concrete mixer truck hydraulic drive systems
Lifting Equipment: crane hydraulic systems, hoist mechanisms, slewing drives
Industrial: high-speed mixing equipment, conveyor drives, fan drives
Marine: deck machinery, winch drives
Material Handling: forklift hydraulic systems, aerial work platforms
Auxiliary Systems: auxiliary/charge pump in larger hydraulic systems
Expert Maintenance Tips
1. Installation Requirements and Housing Priming: Pump/motor and prime mover or load connection shall use elastic coupling, with coaxiality not exceeding 0.1 mm after connection. The drain port must be at the highest position of the component itself during installation, ensuring the pump/motor housing is filled with oil. Fill the housing with clean hydraulic oil before first startup. When the pump is self-priming, the pump installation position should be lower than the minimum oil level in the tank to ensure unobstructed suction piping and minimize suction resistance.
2. Oil Selection and Viscosity Control: The A2F series is suitable for mineral oil (RE 90220), environmentally acceptable hydraulic fluids (RE 90221) and HF hydraulic fluids (RE 90223). The fixed pump A2F is unsuitable for operation with HFA. No. 40 low-pour hydraulic oil is recommended, with optimal operating viscosity range of 16–36 mm²/s, maximum allowable viscosity of 1000 mm²/s and minimum allowable viscosity of 10 mm²/s. VG 46 or VG 68 is recommended at 60°C operating temperature, with the higher viscosity class VG 68 preferred.
3. Drain Line Management and Temperature Control: The drain line must be unobstructed, and case drain pressure must not exceed 0.1 MPa. Case drain temperature is affected by pressure and speed and is always higher than tank temperature. At no point in the system may the temperature be higher than 115°C for sizes 5 to 200 or 90°C for sizes 250 to 500. Replace hydraulic oil and filter after the first 500 hours, then follow a 2,000-hour or annual replacement cycle.
4. Filtration Accuracy and Cleanliness Control: Optimal filtration accuracy is 5–10 μm, with a minimum not exceeding 25 μm. Maintain system oil cleanliness at ISO 4406 18/16/13 or better. Pump/motor connecting pipes and fittings shall be strictly cleaned, with no residual debris allowed inside the pipes.
5. Periodic Tapered Piston Group and Bearing Inspection: The A2F55’s tapered piston rings and bent-axis bearings are primary wear components. Inspect tapered piston ring wear, cylinder bore clearance and bent-axis bearing clearance every 2,000 hours. Abnormal efficiency loss, noise or vibration requires immediate shutdown and service. Use Rexroth original specification parts when replacing piston groups to ensure fit accuracy and assembly torque per technical manual requirements. This series pump/motor is a precision hydraulic component; in case of malfunction, it should not be disassembled by the user to avoid unnecessary losses.
