Product Overview
The A10VSO74DFLR/31R-PSC12N00 is the 74 cc-class core model within the Bosch Rexroth A10VSO series 31 of open-circuit axial piston variable displacement pumps. The A10VSO series features a swash plate design where pump flow is proportional to drive speed and displacement, with output flow steplessly variable via swash plate angle adjustment. Designed for open-circuit hydrostatic drives, the series operates at a nominal pressure of 280 bar with peak pressure of 350 bar.
A10VSO Series Core Features: Variable displacement axial piston pump in swash plate design for open circuit; flow is proportional to rotational speed and displacement; stepless flow adjustment by adjusting the swash plate angle; 2 case drain ports; excellent suction characteristics; low noise; long service life; outstanding power-to-weight ratio; versatile control options; short control response times; through-drive capable for mounting gear pumps or axial piston pumps up to the same nominal size; suitable for mineral oil and fire-resistant hydraulic fluids.
Model Code Breakdown (for procurement and engineering reference):
A10VSO: Rexroth open-circuit swash plate axial piston variable pump (A10VS = standard industrial version, O = open circuit)
74: Nominal size (NG), geometric displacement 74 cm³/rev. Note: The 74 size is an enhanced displacement version of the 71 size, sharing the same housing
DFLR: Pressure, flow and power composite control (Druck-Förderstrom-Leistungsregler) — integrating pressure regulator, flow regulator and power limiter into one module
/31: Series 31 (Baureihe 3, Index 1)
R: Clockwise rotation (viewed from shaft end)
PSC12N00: P = NBR seals (nitrile rubber); S = ANSI B92.1a standard splined shaft (standard torque); C = port configuration code; 12 = additional configuration code; N00 = without through-drive (standard)
Drop-in Replacement Advantage: Manufactured to exact Rexroth OEM specifications, this pump achieves complete drop-in interchangeability with the original A10VSO series 31 for ISO 3019-2 metric mounting flange, ANSI B92.1a splined shaft, SAE flange port layout, and DFLR control module interface. Every pump undergoes 100% simulated load testing prior to shipment, validating 280 bar pressure loading, DFLR composite control response, and volumetric efficiency under conditions replicating real-world duty cycles.
Technical Specifications
Model A10VSO74DFLR/31R-PSC12N00:
Model Code: A10VSO74DFLR/31R-PSC12N00
Series: Rexroth A10VSO Series 31 (Open Circuit, Swash Plate Design)
Nominal Size: NG 74
Geometric Displacement: 74 cm³/rev
Nominal Pressure: 280 bar (continuous)
Peak Pressure: 350 bar (intermittent)
Minimum Speed: 600 rpm
Maximum Speed: Approx. 2200 rpm
Theoretical Flow at 1500 rpm: 111 L/min
Theoretical Flow at 2200 rpm: 162.8 L/min
Control Type: DFLR — Pressure, Flow and Power Composite Control
Pressure Control Range: 30–280 bar (standard setting 280 bar)
Flow Control Range: 2–74 cm³/rev
Power Control: Built-in power limiter, mechanically adjustable
Rotation: Clockwise (viewed from shaft end, R code)
Seal Material: NBR (nitrile rubber), suitable for mineral oil-based hydraulic fluid
Shaft: ANSI B92.1a standard splined shaft (S code), standard torque rated
Mounting Flange: ISO 3019-2 metric 2-bolt flange
Main Ports: SAE flange connections, metric fixing threads, side opposite arrangement
Case Drain Ports: 2 drain ports
Housing Material: High-strength cast iron
Fluid Cleanliness: ISO 4406 18/15/12 or better
Weight: Approx. 33 kg
Operating Temperature: 30–90°C
Through Drive Capability: N00 = without through-drive (standard configuration)
A10VSO Series Displacement Size Reference:
A10VSO18: 18 cm³/rev, max speed 3300 rpm, weight approx. 12 kg
A10VSO28: 28 cm³/rev, max speed 3000 rpm, weight approx. 15 kg
A10VSO45: 45 cm³/rev, max speed 2600 rpm, weight approx. 21 kg
A10VSO71: 71 cm³/rev, max speed 2200 rpm, weight approx. 33 kg
A10VSO74: 74 cm³/rev, max speed 2200 rpm, weight approx. 33 kg
A10VSO100: 100 cm³/rev, max speed 2000 rpm, weight approx. 45 kg
A10VSO140: 140 cm³/rev, max speed 1800 rpm, weight approx. 60 kg
Key Technical Advantages
1. DFLR Pressure, Flow and Power Composite Control
The A10VSO74DFLR/31R-PSC12N00 is equipped with the DFLR composite controller, the most comprehensive control option in the Rexroth A10VSO series. DFLR integrates a pressure regulator (DR), flow regulator (DFR), and power limiter (LR) into a single module. The DFLR controller’s flow is determined by the pressure differential across a throttle valve, making it independent of drive speed variations, while the constant power control limits the pump’s input power through pressure changes. When in the power limiting region, the pump automatically adjusts displacement so that input power does not exceed the setpoint; when load flow demand decreases, the flow regulator automatically reduces displacement to maintain constant throttle pressure drop; when system pressure reaches the pressure cut-off setting, the pump enters constant pressure control mode. This composite control method enables optimal energy utilization across the entire operating range of the hydraulic system.
2. Swash Plate Design with High Power Density
The A10VSO series employs a swash plate axial piston rotary group design where swash plate inclination angle determines piston stroke and displacement. The size 74 achieves a theoretical flow of up to 162.8 L/min at 2200 rpm and 280 bar nominal pressure, leading its displacement class in power density. The swash plate configuration offers compact axial dimensions suitable for space-constrained industrial installations. The series delivers outstanding power-to-weight ratio and short control response times.
3. Excellent Suction Characteristics with Low Noise Operation
The A10VSO series delivers excellent suction characteristics, with optimized suction flow passages reducing cavitation risk and aeration damage. The housing is precision-cast from high-strength cast iron, with the material’s damping characteristics effectively suppressing structural vibration and fluid-borne noise, achieving industry-leading noise levels.
4. Through Drive and Modular System Expansion
The A10VSO series supports through drive, allowing direct mounting of gear pumps or same-size axial piston pumps on the rear of the main pump for single-motor multi-pump compound hydraulic systems, supporting up to 100% through-drive power. Modular control designs enable field conversion and upgrade, with standardized mounting interfaces requiring no adaptation for replacement.
5. High Pressure Capability with Long Service Life
The A10VSO series is renowned for exceptionally long service life, employing long-life, high-precision bearings selected through system-level load analysis for long-term stable operation at 280 bar continuous pressure. The ISO 3019-2 metric 2-bolt mounting flange provides a robust mounting foundation, and the S-type splined shaft (ANSI B92.1a) accommodates standard torque loads.
6. Wide Hydraulic Fluid Compatibility
The A10VSO series is compatible with mineral oil and HF-type fire-resistant hydraulic fluids (HFA, HFB, HFC excluding Skydrol). The seal material is NBR (nitrile rubber), standard configuration for mineral oil-based hydraulic fluids. For HF-type hydraulic fluid applications, select FKM seal configuration (V code).
Application Areas
Plastic Injection Molding Machines: Clamp and injection hydraulic systems (one of the core application areas for the A10VSO series)
Industrial Hydraulic Power Units (HPU): Small to medium hydraulic power units, central oil supply systems
Pressing Equipment: Hydraulic presses, stamping equipment hydraulic power sources
Machine Tools: CNC machine hydraulic systems, hydraulic fixtures
Metallurgical Equipment: Rolling mill hydraulic systems, smelting equipment hydraulic power sources
Mining Machinery: Mine hoist hydraulic systems, crusher hydraulic drives
Marine & Offshore: Ship deck machinery hydraulic drives, marine winch hydraulic systems
General Industrial Automation: Hydraulic actuators, automated production line hydraulic systems
Expert Maintenance Tips
1. Hydraulic Fluid Cleanliness
The A10VSO series DFLR control spool operates with extremely tight clearances and is highly sensitive to particulate contamination. System fluid cleanliness must meet ISO 4406 18/15/12 or better. Install a 10 μm absolute-rated filter element at the pump inlet. Replace elements at 500 hours after first commissioning, then every 1,000 operating hours or 6 months, whichever comes first.
2. DFLR Composite Controller Commissioning Procedure
The DFLR controller should be adjusted in the following sequence: first set the pressure controller (DR) pressure cut-off value, adjustment range 30–280 bar; then adjust the flow controller (DFR) throttle pressure differential setting to ensure stable pressure drop across the system throttle valve; finally adjust the power limiter (LR) power control curve start point. Specifically: after completing Qmax and Pcomp adjustments, locate the power limit adjustment screw (marked Power/HP lim), apply load and run at rated speed, and adjust the screw to set the power curve (P×Q=constant). Adjust only with the system at zero load. Rotate the adjustment screw slowly and verify stable pressure gauge readings before proceeding.
3. Case Drain Line Requirements
The case drain line must return directly to the reservoir. Maximum permissible back pressure is 2 bar (0.2 MPa). The A10VSO series is equipped with two case drain ports. The drain outlet must terminate below oil level at all times to prevent air ingestion. The drain line diameter must not be smaller than the pump case drain port size.
4. Pre-Start Priming and Air Bleeding
Before first start, fill the pump housing with clean hydraulic fluid through the case drain port. After installation, turn the drive shaft by hand several revolutions to confirm free rotation without binding. Start at low speed with zero load and run for 5–10 minutes. Verify continuous bubble-free flow from the case drain. Only then apply load.
5. Splined Shaft and Coupling Maintenance
The A10VSO74 uses an ANSI B92.1a standard splined shaft (S code). Ensure drive shaft alignment during installation, employing a flexible coupling. Apply appropriate grease to the spline connection to prevent fretting wear. Inspect coupling alignment and spline wear at 500 hours after first commissioning, then recheck every 2,000 operating hours.
