Rexroth A2VK variable displacement hydraulic pump

The A2VK is a variable displacement axial piston pump built on the bent-axis design, produced by Bosch Rexroth as part of its A2V/A2VK product family. Unlike swash-plate pumps (like the more common A4VG or A10VG series), the A2VK tilts the entire cylinder block relative to the drive shaft to vary displacement, rather than tilting a swash plate against a fixed cylinder block.

How the A2VK Pump Works

The Bent-Axis Principle

In a bent-axis pump, the cylinder block sits at an angle to the drive shaft rather than in line with it. Pistons connect to the drive flange through ball joints, and as the shaft rotates, the angled arrangement forces the pistons in and out of their bores — drawing in fluid on one side and displacing it on the other.

Changing the bend angle between the cylinder block and the drive shaft changes the stroke length of each piston, which directly changes displacement per revolution. Swing that angle toward zero, and displacement approaches zero. Increase it, and displacement — and flow — increase proportionally.

This is mechanically different from swash-plate pumps, and it matters in practice because bent-axis units generally tolerate:

Higher operating pressures for a given frame size

Greater misalignment and shock loading

More compact packaging in certain mounting orientations

Displacement Control

The "K" in A2VK typically denotes a specific control variant within the family (control options vary by generation and region, so always confirm against the current Rexroth datasheet for your unit). Broadly, displacement adjustment on these pumps is handled through one of the standard Rexroth control philosophies:

Pressure control (DR): limits maximum system pressure by de-stroking the pump as a set pressure threshold is reached

Power control (LR/DA): holds the prime mover's power draw within a defined limit across the speed range

Load-sensing (LS): matches pump flow to actual downstream demand, minimizing throttling losses

Electric proportional control (EP): allows displacement to be commanded directly by a controller, useful in systems with electronic drive management

Construction and Key Components

Housing and Bearing Arrangement

The A2VK uses a robust housing that supports the drive shaft on heavy-duty bearings capable of absorbing both the radial loads from external belt or gear drives and the axial reaction forces generated internally by the bent-axis geometry. This bearing arrangement is one reason these pumps hold up well in applications with side-loaded shafts.

Cylinder Block and Piston Assembly

The cylinder block houses the pistons and rotates with the drive shaft. Piston shoes connect through ball-and-socket joints to the drive flange, transmitting force at the bend angle rather than through a swash plate. Precision-ground bores and pistons keep internal leakage low, which preserves volumetric efficiency even as the pump ages.

Control Valve and Servo Piston 

A servo piston, actuated by the selected control type (DR, LS, EP, etc.), physically swings the cylinder block to the commanded angle. This is the pump's "brain and muscle" — it's what translates a pressure signal, a lever position, or an electrical command into an actual change in flow output.

Shaft Seal and Case Drain

Like all axial piston pumps, the A2VK requires a case drain line to route internal leakage back to the tank, and a shaft seal rated for the pump's case pressure. Undersized case drain lines are a frequent, avoidable cause of premature seal failure in the field.

Typical Applications

Mobile construction equipment — excavator auxiliary drives, drum mixers, compactors

Agricultural machinery — self-propelled sprayers, forage harvesters, specialty drive systems

Municipal and utility vehicles — sweepers, vacuum trucks, and similar PTO-driven hydraulic circuits

Industrial machinery — winches, conveyors, and other variable-speed drive applications where a bent-axis pump's compact envelope and high-pressure tolerance are advantageous

For more information on the A2VK hydraulic pump, please visit https://www.baolilaihydraulic.com/product/.

Specifications

Selection Table

Q1: Is the A2VK a swash-plate or bent-axis pump?

A1: Bent-axis. The cylinder block itself tilts relative to the drive shaft to vary displacement, unlike swash-plate designs, where a fixed cylinder block is driven in line with the shaft and a tiltable plate varies stroke.

Q2: What causes most premature failures in variable displacement piston pumps like the A2VK?

A2: Contamination-related wear and dry starts are the two most common root causes industry-wide, followed by installation issues like misalignment and incorrect case drain routing. Genuine manufacturing defects are comparatively rare.

Q3: How to purchase an A2VK 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 A2VK hydraulic pump?

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