Rexroth A4VHO axial piston hydraulic pumps

The A4VHO is a variable-displacement axial piston pump built in swashplate design, manufactured by Bosch Rexroth AG for open-circuit hydrostatic drives. It belongs to the same family as the better-known A4VSO and A4VBO series, but it's purpose-built for the high-pressure end of the range — currently offered in Size 450 (NG 450), with a nominal pressure of 630 bar and a maximum pressure rating of 700 bar.

That pressure class is the whole point of the design. Where a standard A4VSO tops out around 350 bar, the A4VHO is engineered specifically for applications where 350 bar simply isn't enough — think high-force presses, heavy metal-forming lines, and test rigs that need to simulate extreme loads.

Key identifiers at a glance:

Design type: Swashplate, variable displacement, open circuit

Displacement: Up to 450 cm³ per revolution (Vg max)

Nominal pressure: 630 bar

Maximum pressure: 700 bar

Maximum speed: 1,500 rpm

Maximum flow: Up to 675 l/min at nominal speed and full displacement

Power output: Up to 709 kW at nominal pressure and full displacement

Control option: HS5 electro-hydraulic control with proportional valve

Where the A4VHO Actually Gets Used

This isn't a general-purpose pump, and Rexroth doesn't market it as one. It shows up specifically where standard 350-bar architecture runs out of headroom.

Heavy Press and Forming Applications

Metal-forming presses — forging presses, deep-drawing presses, extrusion presses — routinely need pressure spikes well above what a conventional A4VSO can deliver comfortably. The A4VHO's 630 bar nominal rating (with 700 bar peak capability) lets machine builders hit those forces without stacking multiple lower-pressure pumps or oversizing cylinders just to compensate for the pressure headroom they don't have.

High-Force Test Rigs

Structural and fatigue test rigs that simulate extreme loading — aerospace component testing, automotive structural testing, large-scale material testing — need a pump that can deliver both high pressure and a fast, accurate response to rapidly changing setpoints. The HS5 control's sub-second actuating time (as low as 300 ms) and tight linearity specs make the A4VHO a natural fit for closed-loop servo-hydraulic test systems.

Combination and Tandem Pump Setups

Because many industrial machines need more than one independent hydraulic circuit, Rexroth designed the A4VHO to be combined with a second A4VHO or an A4VSO pump on a shared through-drive, eliminating the need for a separate splitter gearbox. A typical combination — for example, A4VHO 450 + A4VSO NG250 — lets one prime mover drive two independent circuits at two different pressure classes from a single shaft.

Installation and Maintenance Considerations

A few practical notes that come up repeatedly in the field:

Bearing flushing is mandatory, not optional. Ports U and U1 must always be connected, with a flushing quantity of 10 l/min each, or the pump's bearings run without adequate cooling and lubrication.

Orientation affects air bleeding. In "drive shaft upward" installation positions, complete filling and air bleeding before startup is critical — running dry, even briefly, on a pump this size is an expensive mistake.

Preservation has a shelf life. Units ship with protection good for up to 12 months in standard storage; anything longer needs to be specified at order time.

A pressure relief valve is still required. The pump's own pressure controller is not a substitute for system-level overpressure protection — Rexroth is explicit about this in its safety documentation.

Watch the natural frequency. At certain rotational speeds, the pump's excitation frequency (roughly nine times shaft speed) can resonate with the hydraulic system's natural frequency. Line routing and dampening are the usual fixes.

For more information on the A4VHO hydraulic pump, please visit https://www.baolilaihydraulic.com/product/.

Specifications

Selection Table

Q1: How is the A4VHO controlled?

A1: Primarily through the HS5 electro-hydraulic control — a proportional valve with an inductive position transducer feeding back to Rexroth's VT-HPC-1-1X control electronics, enabling closed-loop displacement, pressure, and torque control.

Q2: Can two A4VHO pumps be mounted in tandem?

A2: Yes. Rexroth supports tandem and combination mounting of an A4VHO with a second A4VHO or with an A4VSO/A4VBO pump on a shared through-drive, allowing independent hydraulic circuits from a single prime mover without a splitter gearbox.

Q3: How to purchase an A4VHO hydraulic pump?

A3: You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.

Q4: What is the price and delivery time of the A4VHO hydraulic pump?

A4:The specific price and delivery time will be provided based on the specific model you provide.