Rexroth AA4VSO355 Open circuit piston hydraulic pump

The AA4VSO355 is built on the swashplate design, an engineering framework optimized for variable displacement in open-circuit configurations. In an open circuit, hydraulic fluid flows from the reservoir to the pump, travels to the consumers (valves and cylinders), and returns directly back to the tank.

Modular Control Options: Tailoring the Output

One of the primary reasons engineers specify the Rexroth AA4VSO355 is its extensive range of modular control devices. The pump doesn't just push fluid; it actively communicates with and adapts to the system's load requirements.

1. Power Controls (LR2, LR3)

These controllers regulate the pump's displacement relative to the operating pressure so that the drive power (input torque) remains constant. This prevents the electric motor or diesel engine from stalling under sudden high loads.

2. Pressure Controls (DR, DRG)

The pressure control overrides the displacement function to maintain a constant pressure within the hydraulic system. When the preset pressure is reached, the pump automatically de-strokes (reduces flow to near zero) to maintain that pressure without wasting energy.

3. Electro-Proportional Controls (HS4, EO2)

For modern, automated industrial setups, electro-proportional displacement controls integrate seamlessly with electronic control units (ECUs) or PLCs. This allows for digital closed-loop control of pressure, flow, and power via proportional valves.

Real-World Applications: Where the AA4VSO355 Excels

The 355cc displacement size is engineered for heavy industrial environments where smaller, medium-duty pumps fail.

Heavy Industrial Presses

In metal forging or deep-drawing hydraulic presses, the AA4VSO355 delivers the immense, sustained pressure required to shape raw steel, while its rapid de-stroking capability ensures safe pressure holding phases.

Marine and Offshore Machinery

From massive deck winches on cargo ships to steering gear and offshore drilling rigs, this pump is frequently specified with special sealing compounds and corrosion-resistant coatings to withstand harsh, salty environments.

Civil Engineering and Mining

Large-scale tunnel boring machines (TBMs), mining excavators, and heavy material handling systems rely on the AA4VSO355 to actuate high-torque hydraulic motors under unpredictable load spikes.

Maintenance and Longevity: Best Practices

Investing in a component of this caliber requires a rigorous preventative maintenance strategy to ensure a return on investment.

Fluid Cleanliness is Paramount

Axial piston pumps operate with incredibly tight tolerances between the pistons and the cylinder boring. Contamination is the number one killer of these systems.

Maintain a minimum fluid cleanliness level of ISO 4406 18/16/13.

Regularly sample hydraulic oil for varnish, water ingress, and particulate matter.

Case Drain Monitoring

The case drain line relieves internal leakage back to the reservoir, keeping the pump housing cool and lubricated. Monitoring the temperature and flow rate of the case drain line is the best way to diagnose internal wear before a catastrophic failure occurs. A sudden spike in case drain flow indicates worn piston shoes or valve plates.

For more information on the AA4VSO355 hydraulic pump, please visit https://www.baolilaihydraulic.com/product/.

Specifications

Selection Table

Q1: What is the difference between the Rexroth A4VSO and the AA4VSO?

A1: The "A4VSO" is the standard European/Global designation, while the "AA4VSO" typically denotes a version manufactured or configured to meet American standards (SAE mounting flanges, shaft configurations, and port threads). Internally, the core hydraulic design and performance specs remain highly consistent.

Q2: What causes a Rexroth piston pump to become excessively noisy?

A2: Excessive noise in an AA4VSO355 is usually caused by **cavitation** (air bubbles forming and collapsing in the fluid due to restricted suction), aeration (air entering the suction line), or severe internal mechanical wear (such as a damaged swashplate bearing). Inspect the suction strainer and check for loose fittings immediately if noise levels rise.

Q3: What is the price and delivery time of the AA4VSO355 hydraulic pump?

A3: The specific price and delivery time will be provided based on the specific model you provide.

Q4: How to purchase an AA4VSO355 hydraulic pump?

A4: You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.