A4VG140EP4D11/32L-NSF60F021DP-S Rexroth Closed Circuit Pump 400 bar

Product Overview:

The A4VG140EP4D11/32L-NSF60F021DP-S belongs to the Bosch Rexroth A4VG series of closed-circuit high-pressure variable displacement axial piston pumps (related sizes include A4VG90 and A4VG125). Featuring a swash-plate design for hydrostatic closed-circuit transmissions, flow is proportional to drive speed and displacement and is infinitely variable. Swivelling the pump over centre smoothly changes the direction of flow. Fully interchangeable with genuine Rexroth units, it enables direct drop-in replacement without modification to mounting interfaces or piping. Every unit undergoes 100% simulated operating-condition testing to ensure high efficiency and reliability under high pressure.

Technical Specifications 

• Model: A4VG140EP4D11/32L-NSF60F021DP-S (related series A4VG90 / A4VG125)
• Displacement (Vg max): A4VG90 90 cm³/rev; A4VG125 125 cm³/rev (A4VG140 is a closely related size in the series)
• Continuous / Rated Pressure: up to 400 bar
• Peak / Intermittent Pressure: up to 450 bar
• Continuous Max. Speed (at Vg max): A4VG90 approx. 3050 rpm; A4VG125 approx. 2850 rpm
• Control Type: Variable (EP electric proportional, etc., code dependent)
• Design: Swash-plate axial piston, closed circuit (with integral boost pump)
• Weight: A4VG90 approx. 60 kg; A4VG125 approx. 80 kg
• Brand / Series: Bosch Rexroth A4VG closed-circuit high-pressure variable piston pump

Key Technical Advantages:

1. Closed-Circuit High-Pressure Design: Continuous rating of 400 bar and peak of 450 bar, optimized for hydrostatic transmissions, deliver high power density in a compact package.
2. Infinitely Variable Displacement & Bidirectional Flow: Displacement is steplessly adjustable from 0 to Vg max. Crossing centre smoothly reverses flow direction, ideal for reversible drive systems.
3. Integral Boost Pump & Safety Valves: Built-in boost pump supplies make-up and control oil. Dual high-pressure relief valves protect the transmission from overload, enhancing system reliability.
4. Versatile Controls & High Efficiency: Supports electric proportional (EP) and other control options. Optimized swash-plate geometry maintains high volumetric efficiency and low noise.
5. True Interchangeability & Long Service Life: Fully compatible with OEM mounting dimensions and interfaces. High-load bearings and precision manufacturing ensure reliable long-term operation.

Application Areas:

• Travel drive systems on construction machinery (excavators, loaders, rollers, cranes)
• Agricultural and forestry equipment hydrostatic transmissions
• Port and material-handling equipment
• Industrial closed-circuit hydraulic drive systems
• Any mobile or stationary application requiring bidirectional variable control

Expert Maintenance Tips:

1. Ensure proper drive-shaft alignment during installation; use a flexible coupling and avoid excessive radial/axial loads. Verify correct closed-circuit piping connections.
2. Use anti-wear hydraulic oil meeting ISO cleanliness and viscosity requirements; system filtration should be at least 10 μm. Thoroughly bleed air and check case and boost pressure before initial start-up.
3. Regularly monitor boost pressure and case drain to prevent cavitation or over-pressure. Verify control signals and relief valve settings.
4. During service, inspect pistons, cylinder block and valve plate for wear; replace complete rotating groups when necessary. Store long-term units in a dry environment and rotate the shaft periodically.