Product Overview
The A2F5W3P1 and A2F6W3P1 are small-displacement models within the Bosch Rexroth A2F series of bent-axis fixed displacement axial piston pumps and motors. Featuring a bent-axis design with fixed displacement, these units operate as either pumps or motors in open or closed hydrostatic drive circuits. When operating as a pump, flow is proportional to drive speed and displacement; when operating as a motor, output speed is inversely proportional to displacement, and output torque increases with the pressure differential between high and low pressure sides.
The model code breakdown: A2F denotes fixed displacement bent-axis pump/motor; 5 and 6 indicate displacement sizes (4.93 cc/rev and 6.0 cc/rev); W indicates alternating (bi-directional) rotation; 3 is the series number; P1 denotes keyed shaft and port plate specification 1.
Manufactured to exact Rexroth OEM specifications, these units deliver true drop-in interchangeability with original A2F series pumps — same mounting flange, P1 keyed shaft, port configuration, and rotation direction. Every unit undergoes 100% simulated load testing prior to shipment, validating volumetric efficiency and thermal stability under conditions replicating real-world duty cycles.
About the A2F Series: The Rexroth A2F series spans displacements from 4.93 cc/rev (A2F5) to 1000 cc/rev (A2F1000), available in open and closed circuit configurations for construction machinery, mining equipment, and industrial hydraulic systems.
Technical Specifications
Model A2F5W3P1:
Model Code: A2F5W3P1
Series: Rexroth A2F (Bent-Axis Fixed Displacement Pump/Motor)
Displacement: 4.93 cc/rev (4.93 cm³/rev)
Rated Pressure: 315 bar
Peak Pressure: 350 bar
Rated Speed: 5600 rpm
Theoretical Flow at Rated Speed: Approx. 27.6 L/min
Theoretical Torque (Δp = 315 bar): Approx. 24.7 N·m
Input Power (Δp = 315 bar): Approx. 14.5 kW
Control Type: Fixed Displacement (Quantitative)
Rotation: Bi-directional (W — Alternating)
Shaft: P1 — Keyed shaft (GB1096-79)
Mounting: Flange mount
Housing Material: High-strength cast iron
Operating Temperature: -25°C to +80°C (case drain)
Weight: Approx. 2.5 kg
Model A2F6W3P1:
Model Code: A2F6W3P1
Series: Rexroth A2F (Bent-Axis Fixed Displacement Pump/Motor)
Displacement: 6.0 cc/rev (6.0 cm³/rev)
Rated Pressure: 315 bar
Peak Pressure: 350 bar
Rated Speed: 5600 rpm
Theoretical Flow at Rated Speed: Approx. 33.6 L/min
Theoretical Torque (Δp = 315 bar): Approx. 30.1 N·m
Input Power (Δp = 315 bar): Approx. 17.6 kW
Control Type: Fixed Displacement (Quantitative)
Rotation: Bi-directional (W — Alternating)
Shaft: P1 — Keyed shaft (GB1096-79)
Mounting: Flange mount
Housing Material: High-strength cast iron
Operating Temperature: -25°C to +80°C (case drain)
Weight: Approx. 2.5 kg
A2F Series General Specifications (Reference):
Rated Pressure (Sizes 10–200): 400 bar
Peak Pressure (Sizes 10–200): 450 bar
Rated Pressure (Sizes 250–1000): 350 bar
Peak Pressure (Sizes 250–1000): 400 bar
Circuit Type: Open circuit / Closed circuit
Mounting: SAE flange / ISO flange
Shaft Options: Keyed shaft / Splined shaft
Key Technical Advantages
1. Bent-Axis Design with High Power Density
The A2F series employs a bent-axis tapered piston rotary group design, where the piston axis is angled relative to the drive axis. The key advantage: minimal lateral force exerted by pistons on the cylinder block, reducing the tilting moment between the cylinder block and valve plate, allowing the rotary group to maintain a stable hydrostatic bearing film at high speeds. Compared to swash plate designs, the bent-axis configuration achieves higher power density and more compact dimensions at equivalent displacement. The A2F5 and A2F6 achieve power densities of approximately 5.8 kW/kg and 7.0 kW/kg respectively, leading their displacement class.
2. One-Piece Tapered Piston with Piston Ring Sealing
The piston features a one-piece tapered design with piston rings for sealing between the piston and cylinder bore. Piston ring sealing provides superior sealing performance and lower leakage compared to conventional clearance sealing. The elastic deformation capability of the piston rings compensates for thermal expansion differences between the piston and cylinder bore, maintaining stable volumetric efficiency across a wide temperature range.
3. Self-Centering Spherical Control Area with Long-Life Bearings
The A2F rotary group incorporates a well-proven self-centering spherical control area design, where pistons automatically center within the spherical zone, achieving torque-free piston bearing support. This design reduces friction and wear between the piston and cylinder bore while enabling the drive shaft to accommodate radial loading. The drive shaft uses robust rolling bearings selected through system-level load analysis for long service life at high speeds.
4. True Drop-in Interchangeability with High-Strength Cast-Iron Housing
The A2F5W3P1 and A2F6W3P1 are dimensionally matched to the original Rexroth A2F specification for mounting flange, P1 keyed shaft, port layout, and rotation direction, achieving complete drop-in interchangeability. The high-strength cast-iron housing provides superior structural damping, effectively suppressing structural vibration and fluid-borne noise. The two-piece housing construction simplifies field service and reduces equipment downtime.
5. Bi-Directional Rotation with Wide Hydraulic Fluid Compatibility
The W-code A2F5W3P1 and A2F6W3P1 support bi-directional (alternating) rotation, suitable for hydraulic systems requiring forward/reverse switching. The units are compatible with mineral oil (per DIN 51524) and HFB, HFC, and HFD environmentally acceptable hydraulic fluids. A2F series pumps are not suitable for operation with HFA hydraulic fluid.
Application Areas
Construction Equipment: Mini excavator travel drives, compact wheel loader hydraulic systems, vibratory roller vibration circuits
Industrial Equipment: Hydraulic fixture power sources, machine tool coolant pump drives, hydraulic test benches
Material Handling: Electric forklift travel drives, small lift platform hydraulic motors
Environmental Equipment: Dust collector fan hydraulic drives (A2F5/A2F6 with dust collector fans is a typical application in this field)
Marine & Offshore: Deck machinery hydraulic drives, small steering gear hydraulic systems
Agricultural Machinery: Compact tractor hydraulic hitch systems, mower hydraulic drives
Expert Maintenance Tips
1. Hydraulic Fluid Cleanliness
A2F series pumps are highly sensitive to fluid contamination, particularly given the extremely tight clearances between the one-piece tapered piston and piston rings. System filtration must meet ISO 4406 18/15 or better. Replace filter elements at 500 hours after first commissioning, then every 1,000 operating hours or 6 months, whichever comes first. Finer filtration improves fluid cleanliness levels, which directly extends the service life of the axial piston unit.
2. Pre-Start Priming and Air Bleeding
Before first start, fill the pump housing with clean hydraulic fluid through the uppermost case drain port. After installation, turn the drive shaft by hand several revolutions to confirm free rotation without binding. Start at low speed with zero load and run for 5–10 minutes. Verify continuous bubble-free flow from the case drain. For “drive shaft upwards” installation positions, filling and air bleeding must be performed completely as there is a risk of dry running.
3. Hydraulic Fluid Viscosity and Temperature Control
Optimum operating viscosity range is 17–180 cSt. Case drain temperature is influenced by pressure and speed and is always higher than reservoir temperature. System temperature must never exceed 115°C (sizes 5–200) at any point. For continuous high-temperature applications, select a higher viscosity grade hydraulic fluid.
4. Installation Alignment and Plumbing
Ensure drive shaft alignment with radial deviation not exceeding 0.05 mm. The case drain line must return directly to the reservoir with back pressure not exceeding 2 bar (0.2 MPa). The drain outlet must terminate below oil level at all times. Minimum absolute pressure at the suction port must be maintained at 0.08 MPa (absolute) or higher to prevent cavitation.
5. Preventive Replacement of Piston Rings and Valve Plate
Piston rings and the valve plate are key wear components. Perform preventive inspection at 8,000–10,000 operating hours. Replace if piston ring tension decreases, valve plate surface scoring is evident, or volumetric efficiency drops significantly. When replacing piston rings, simultaneously inspect cylinder bore wall wear to ensure mating surface integrity.
