Rexroth Axial Piston Variable Pump A4VSO

General:

During commissioning and operation, it is crucial to fill the axial piston unit with hydraulic fluid and bleed the air. This procedure should also be followed after extended periods of inactivity, as the axial piston unit may drain through the hydraulic lines. This is especially important for installations with the drive shaft facing upwards, as improper filling and air bleeding could lead to dry running.

Direct the leakage from the housing area to the reservoir through the highest drain port (T, K1, K2, R(T)). For combination pumps, ensure that each pump’s leakage is drained individually. If multiple units share a drain line, ensure that the case pressure of each unit does not exceed the permissible limit. The shared drain line must be sized to maintain the maximum permissible case pressure for all connected units under any operating conditions, particularly during cold starts. If necessary, use separate drain lines to achieve this.

To reduce noise, decouple all connecting lines using flexible elements and avoid installations above the reservoir. Ensure that, in all operating conditions, both the suction and drain lines flow into the reservoir below the minimum fluid level. The permissible suction height (hS) is determined by the total pressure loss but must not exceed hS max = 800 mm. During operation and cold starts, the minimum suction pressure at port S must not fall below 0.8 bar absolute (without a charge pump) or 0.7 bar absolute (with a charge pump).

When designing the reservoir, maintain adequate distance between the suction line and the case drain line to prevent the heated, possibly foaming return flow from being drawn directly back into the suction line.