Rexroth A4VG71 for Compact Drive Systems
Overview and key specifications
The A4VG71 is a swashplate‑type, variable‑displacement axial‑piston pump for closed‑circuit hydrostatic drives. It features a geometric displacement of 71 cm³/rev, a nominal pressure of 400 bar, and a maximum pressure of 450 bar. At the maximum speed for this size (n max ≈ 3300 rpm at Vg max), the theoretical flow is about 234 L/min. Typical applications include compact drive systems in construction and industrial machines where high power density and responsive control are required.
Parameter | Value |
|---|---|
Displacement (Vg max) | 71 cm³/rev |
Nominal pressure (p nom) | 400 bar |
Maximum pressure (p max) | 450 bar |
Max. speed at Vg max (n max) | 3300 rpm |
Theoretical flow at n max, Vg max | ≈ 234 L/min |
Typical control family | EP / HD / HW / DA / EZ / DG / NV |
Circuit | Closed circuit |
Integrated charge pump | Yes |
Integrated pressure cut‑off | Yes |
Core features and protection
Flow is proportional to drive speed and displacement, and can be varied steplessly from zero to maximum by adjusting the swashplate angle; the pump reverses flow smoothly through neutral.
Two high‑pressure relief valves on the high‑pressure side protect the closed‑circuit transmission (pump and motor) from overload; these also function as charge (boost) valves.
An integrated charge pump supplies pilot and control oil; the maximum charge pressure is limited by an internal relief.
Pressure cut‑off is standard to limit maximum system pressure and reduce unnecessary relief operation.
Compact, robust design with through‑drive capability for adding an auxiliary pump of the same nominal size on the same shaft.
Control options and typical uses
Control families include: NV (no control), DG (direct hydraulic), EZ (electrical two‑point), HD (hydraulic, pressure‑related), HW (mechanical servo), EP (electro‑proportional), DA (hydraulic, speed‑related). Choose the variant that matches your system’s control strategy, response, and interface.
Typical applications for the A4VG family (including size 71) are closed‑circuit drives in construction machinery and industrial systems such as pavers, vibratory rollers, harvesters, coal support carriers, beam transporters, and other compact drive systems requiring high power density and reliable closed‑circuit performance.
Model code and ordering guidance
The A4VG family uses a structured type code (e.g., size, control device, series suffix, mounting/through‑drive, and design variant). Examples of valid A4VG71 variants include: A4VG71DA1DT4/32R‑NZF02F001DH, A4VG71EP2D1/32R‑NZF02F011SH‑E, A4VG71HWD1/32R‑NZF02F001S. Always match the complete type code to your machine’s parts list and the pump nameplate to ensure control compatibility and correct configuration.
Commissioning and maintenance essentials
Pre‑fill and bleed the closed circuit; ensure the charge pump is primed and the oil meets OEM cleanliness and viscosity specs.
Verify through‑drive alignment and coupling end play; check case drain flow and temperature during first runs.
Set high‑pressure relief valves and any installed pressure cut‑off per machine specs; respect the control’s adjustment range and response.
Inspect and, if needed, replace the charge strainer/filter; confirm all electrical connections for the selected control variant.
After start‑up, recheck noise, vibration, and leakage, and confirm the control response matches expected behavior at low and high pressure.
