Core Engineering Principles

Pressure rating: Continuous duty at 350 bar (5,076 psi), intermittent peaks up to 400 bar (5,800 psi).
Displacement variability: Swashplate design enables flow from minimal to full output, cutting parasitic energy losses.
Rear‑mount flexibility: Additional pumps (gear or piston) can be bolted to the rear, saving engine‑bay space.

The twin‑pump layout is vital for load‑sensing circuits – one section can drive travel motors, the other runs attachments, eliminating the need for a separate flow divider.

Swashplate Control Variants

Rexroth provides several regulator options, but the three most frequent on high‑pressure tandem pumps are:

LR (Load‑sensing with pressure limiting): Suited for fluctuating flow/pressure needs (e.g., hammer circuits).
EP (Electro‑proportional): Allows direct electronic displacement adjustment via PLC or joystick signals.
HD (Hydraulic pilot): Used in open‑loop mobile systems where simplicity and ruggedness are priorities.

Installation & Maintenance Essentials

Experienced operators know the A20VO520 delivers long life only when these three rules are followed:

1. Inlet condition: Maintain suction pressure above 0.8 bar absolute; fit a suction strainer of 200 µm maximum.

2. Drain line routing: Each pump section requires its own case‑drain line – never combine them; backpressure above 2 bar will ruin the shaft seal.

3. Initial startup: Pre‑fill both housings through the top port. Running a dry axial piston unit for even 10 seconds destroys the copper‑alloy slippers.