R910999472 AA4VSO250LR2D/30R-VPB13N00 Original German Rexroth piston pump

Rexroth Axial Piston Variable Pump AA4VSO250LR2D/30R-VPB13N00 (R910999472)

FAQ:

Q1: What is the function of the "LR2D" control? How does it differ from DRG?

A:​ The LR2D​ is a sophisticated Power Control (Load-Sensing). Unlike the DRG (Pressure Control) which maintains constant pressure, the LR2D automatically adjusts the pump's displacement to maintain a constant pressure margin (Δp)​ above the load pressure. This ensures the pump delivers only the flow and pressure needed by the system, resulting in significant energy savings. The "D" suffix indicates a specific control characteristic (hyperbolic curve) optimized for high efficiency.

Q2: What does the "VPB13N00" suffix indicate?

A:​ This code defines the mechanical configuration:

• V: FKM (Viton)​ seals, offering superior chemical and high-temperature resistance compared to standard NBR (P).

• P: Standard parallel key shaft​ (DIN 6885).

• B13: Port size code 13​ (SAE flange ports with metric threads).

• N00: No through-drive​ (solid shaft end, cannot mount additional pumps on the shaft).

Q3: What is the key application advantage of the LR2D control?

A:​ The primary advantage is energy efficiency in variable flow systems. It is ideal for machines where the load pressure varies but a constant flow is not always required (e.g., injection molding machines, large presses). It prevents unnecessary high-pressure flow during idle or low-load periods, reducing heat generation and power consumption compared to simple pressure-compensated (DR) pumps.

Q4: How do I connect the LS (Load-Sensing) port?

A:​ The LS port​ must be connected to the highest load pressure point in the system (typically after the directional valve). This feedback signal tells the pump how much pressure to generate. Important:​ The LS line must be protected with a pressure relief valve (typically 400 bar) and a damping orifice to ensure stable control.

Q5: Can this pump be used in a closed-loop hydrostatic system?

A:​ No.​ The A4VSO LR2D is designed exclusively for open-circuit applications​ (pump → valve → actuator → tank). For closed-loop hydrostatic transmissions (e.g., travel drives), you would need an A4VG or A2FM series unit.