The A2FO series axial piston fixed pump utilizes a bent-axis design with tapered piston rotary groups, engineered specifically for hydrostatic drives in open-circuit applications. By maintaining a fixed displacement, the unit provides a constant flow rate proportional to the drive speed and displacement volume, making it a robust solution for industrial and mobile machinery requiring consistent hydraulic power density. The design incorporates a spherical control plate that facilitates self-centering of the cylinder block, effectively minimizing wear and maintaining high volumetric efficiency even under high-pressure differentials.
Operational Characteristics and Design Architecture
The A2FO pump operates on the principle of a bent-axis rotary group, where the cylinder block axis is inclined at an angle relative to the drive shaft axis. This geometry allows for high power-to-weight ratios and exceptional suction characteristics. The pistons are connected to the drive shaft via ball-and-socket joints, ensuring the transmission of torque through the cylinder block.
In accordance with DIN 24340 and ISO 4401 mounting standards, the A2FO is designed for flange mounting, ensuring compatibility with standard power take-off (PTO) interfaces. The pump is capable of continuous pressures up to 350 bar and peak pressures reaching 400 bar, depending on the specific frame size and fluid viscosity parameters.
Technical Specifications Table
| Parameter | Unit | Specification Range |
|---|---|---|
| Displacement (Vg) | cm³/rev | 5 – 500 |
| Maximum Pressure (p_max) | bar | 350 – 400 |
| Max Speed (n_max) | rpm | 1,200 – 6,300 |
| Mounting Standard | – | ISO 3019-2 / DIN 24340 |
| Fluid Temperature Range | °C | -40 to +115 |
Fluid Cleanliness and Contamination Control
System reliability in axial piston units is highly sensitive to particulate contamination. To ensure the longevity of the rotating group and the control plate interface, the hydraulic fluid must meet a minimum cleanliness level of 20/18/15 according to ISO 4406.
Contamination particles exceeding 10–20 microns can lead to “spool silting” in associated control valves or abrasive wear on the cylinder block face, leading to internal leakage and a subsequent drop in volumetric efficiency. It is recommended to utilize pressure-rated filtration systems with a Beta ratio (βx) ≥ 75 to maintain system integrity.
Seal Elastomer Compatibility
The selection of seal materials is critical for the chemical compatibility of the A2FO pump with the working fluid.
* NBR (Nitrile Butadiene Rubber): Suitable for standard mineral oil-based hydraulic fluids (HLP, HLPD) within a temperature range of -40°C to +90°C.
* FKM (Viton): Required for high-temperature applications or when utilizing synthetic hydraulic fluids (e.g., HFD-R phosphate esters). FKM provides superior thermal stability and chemical resistance, preventing seal degradation and external leakage paths.
Users must verify that the chosen seal material is compatible with the specific fluid additives, as some anti-wear (AW) or extreme-pressure (EP) additives can induce premature swelling or hardening of NBR compounds.