Bosch Rexroth A2FM80 axial piston hydraulic motor

The A2FM series has been a benchmark for decades. The “80” refers to its geometric displacement of 80 cc per revolution. What sets it apart is the bentaxis design: pistons operate at an angle to the drive shaft, which yields higher starting torque efficiency and smoother lowspeed operation than swashplate motors.

Design and Construction: What’s Inside

HighPressure Housing and Bearings

The onepiece housing incorporates highcapacity tapered roller bearings that absorb both radial and axial shaft loads. This matters when coupling directly to a pinion or sprocket.

Piston and Cylinder Block

Five or nine pistons? The A2FM80 uses nine pistons for reduced flow ripple. The cylinder block is held against the valve plate by hydraulic force, not mechanical springs—eliminating a common wear point.

Shaft Seal and Drain Ports

Two independent shaft seals (with a leakoff port between them) protect against contamination ingress. Always connect the case drain line to tank with minimal backpressure—exceeding 2 bar absolute will damage the shaft seal.

Applications and Examples

Example 1: Auger Drive on a Skid Steer

Paired with a 45 gpm auxiliary circuit, the A2FM80 delivers 1,800 Nm of torque at 250 bar. Operators report consistent rotation speed even when the auger hits clay or roots—thanks to the motor’s stiff torquespeed characteristic.

Example 2: Plastic Injection Molding Machine Screw Drive

In an industrial setting, the motor sees rapid starts/stops every 4 seconds. The A2FM80’s low compressibility volume (small trapped oil volume between pistons) enables precise screw positioning without a separate braking valve.

Example 3: Marine Crane Slewing Drive

Subject to salt spray and shock loads, the motor’s galvanically protected surfaces and optional stainless steel nameplate extend service life. One port operator noted 12,000 hours before first seal replacement.

Installation and Common Pitfalls

Mounting Orientation

The A2FM80 can be mounted in any position, but the highest case drain port must be uphill to vent air. Never run the motor with trapped air—it causes hammering and breaks the piston slippers.

Shaft Alignment

Misalignment beyond 0.2 mm TIR (total indicator reading) will reduce bearing life by 50%. Use a flexible coupling or cardan shaft if the mounting flange is not perfectly true.

Cold Start Protocol

Below 10°C (14°F), viscosity may exceed 2,000 mm²/s. Run the motor at no load for 2–3 minutes. A common mistake is deadheading the motor on cold oil—this generates transient pressure spikes above 600 bar, cracking the valve plate.

Performance Optimization Tips

Boost pressure: Maintain at least 2 bar absolute at the motor inlet to prevent cavitation in highspeed applications (>2,500 rpm).

Case drain filtration: Install a 10 µm absolute filter in the drain line. Debris from the motor often travels back to tank and reenters the pump.

Torque ripple: At low speed (<50 rpm), expect ±4% torque ripple. Add a flow control valve with damping if precise positioning is required.

For more information on the A2FM80 hydraulic motor, please visit https://www.baolilaihydraulic.com/product/.

Specifications

Selection Table

Q1: How do I know if the A2FM80 is failing internally?

A1:Measure case drain flow. At 250 bar and full speed, drain flow should be <6 L/min. Anything above 10 L/min suggests worn pistons or a scored valve plate.

Q2:Is the A2FM80 interchangeable with an A2F80?

A2:Generally yes—the A2F series was an earlier metric designation. Check the shaft extension and mounting flange pattern (ISO 3019-2 is standard).

Q3:What is the price and delivery time of the A2FM80 hydraulic motor?

A3: The specific price and delivery time will be provided based on the specific model you provide.

Q4:How to purchase an A2FM80 hydraulic motor?

A4:You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.