The A4VSO pump operates on the axial piston principle. It converts mechanical rotation into hydraulic flow by utilizing a rotating cylinder block containing pistons. These pistons reciprocate within their bores as they slide against a tilted swash plate. This reciprocating motion changes the volume of the sealed chambers, drawing in fluid during the expansion phase and pressurizing and expelling it during the compression phase, thereby achieving suction and discharge.

Key advantages include high rated pressure (up to 350 bar, peak 400 bar), compact structure, high efficiency, convenient flow regulation, excellent suction characteristics, low noise levels, long service life, and a wide range of control options (e.g., pressure, flow, power).

• Foundation: The base mount or flange mount must be rigid.
• Alignment: Precise alignment between the drive motor shaft and the pump shaft is crucial. The maximum allowable misalignment is < 0.05mm.
• Shaft Loading: Avoid installing pulleys, chains, or gears directly on the pump shaft, as this imposes radial loads which the pump is not designed to handle.
• Reservoir Mounting: If mounted on the reservoir, the pump's centerline should ideally not be more than 500 mm above the oil surface to facilitate good suction conditions and avoid cavitation.
• Filling: Before initial start-up, the pump casing must be filled with hydraulic oil through the designated filling port.
• Suction Line: Use a flexible connection for the suction line. The use of a suction line filter is generally not recommended; a pressure line filter is preferred.

The pump can be installed in various orientations (horizontal or vertical). For vertical installation with the shaft pointing upwards, external bearing flushing is strongly recommended to ensure adequate lubrication for the front bearing and shaft seal.

Oil Types: Recommended fluids include mineral oils (RC 90220), environmentally friendly fluids (RC 90221), and HF fluids (HFA, HFB, HFC - check seal compatibility, typically FKM for HFD; RC 90223). Specify the fluid type when ordering.

Viscosity Range: The optimal operating viscosity range (at operating temperature) is 16 to 36 mm²/s. Absolute limits are:

• Minimum: 10 mm²/s (short-term, max. case drain temp 90°C)
• Maximum: 1000 mm²/s (short-term, cold start).