A10VSO71 Pump: Compact Axial Piston Powerhouse

The  a10vso71 pump exemplifies Bosch Rexroth's axial piston variable displacement engineering for open-circuit hydrostatic drives. With 71 cm³/rev displacement, this swashplate design delivers maximum flows up to 184 L/min at 2,600 rpm while maintaining 280 bar nominal pressure and 350 bar peaks. Optimized for medium excavators, wheel loaders, and compact cranes, the A10VSO71 balances high performance density, rapid response, and exceptional durability in space-constrained applications.

Technical Specifications and Operating Envelope

A10VSO71 achieves nominal pressure pN of 280 bar continuously, peak pressure pmax of 350 bar for overload conditions. Maximum speed nnom reaches 2,600 rpm at Vg max, producing theoretical flow qV max of 184 L/min. Drive power peaks at 84 kW under nominal conditions, maximum torque Tmax of 280 Nm at full displacement and 280 bar differential.

Viscosity requirements specify νopt 36-50 mm²/s optimal, νmin 10 mm²/s minimum short-term, fluid temperatures -20°C to +110°C (FKM seals standard). Filtration demands 10 µm absolute (β10 ≥75), case pressure pS max 2.5 bar. Unit weight measures 59 kg, SAE B ****** mounting (82 mm bolt circle).

Efficiency ratings include volumetric ηv ≥94%, mechanical ηhm ≥98%, total ηges ≥92% across operating range. Self-priming suction hS max 800 mm, minimum immersion depth 200 mm.

Swashplate Operating Mechanism

Nine axial pistons reciprocate within precision-honed rotating barrel bores, maintaining contact with tilting swashplate via spherical slippers. Piston stroke varies with swashplate angle α (0-18°), generating flow qV = Vg × n × sin α / 1000 (L/min). Counterbored valve plate kidney ports alternately connect barrel ports to suction chamber S and pressure port P.

Optimized port timing minimizes pressure ripple <5%, internal leakage controlled to <2% qV via 0.02 mm piston-to-bore clearances. Case drain R returns leakage for bearing lubrication. Torque calculation T = Vg × Δp / (20π ηhm) yields 280 Nm design maximum.

Control Configurations and Response Characteristics

Pressure compensator (DR) automatically destrokes swashplate at adjustable setpoints 140-350 bar, maintaining constant Δp with hysteresis <4 bar. Load-sensing DFR/DFR1 holds ΔpLS margins 15-25 bar using pilot pressures 10-40 bar, t90 response 50-100 ms against 220 bar.

Electric proportional EP control employs 12/24V solenoids (Imax 1.6A) for programmable ramp stroking. Mechanical servo M enables direct linkage adjustment. Power limiter PL integrates pressure/torque protection curves. Two-point DG switches Vg max/min via port X ≥50 bar.

Servo piston areas optimized for 30:1 force ratios responding to 20-60 bar differentials.

Hydraulic Fluid Requirements

HLP DIN 51524 Part 2 mineral oils satisfy specifications, contamination class /c/ 20/18/15 maximum. Cold-start νmax 1,600 mm²/s permitted 3 minutes maximum; warm-up phase 400-1,000 mm²/s. Bearing flushing qFl 1.5-4 L/min required.

Temperature rise pump-to-fluid ≤13 K preserves seals. Case fill ratio 0.8-1.0 prevents aeration. Suction line ≥DN25 nominal diameter recommended.

Mechanical Interfaces and Standards

SAE B ****** (82 mm bolt circle) standardizes mounting, through-drive supporting tandem configurations to 1.5×Tmax torque. Shaft options: splined SAE B 13T 16/32DP, parallel keyed 32 mm, tapered. Porting SAE J518 code 61 flanges (#16 standard) or threaded SAE J1926/1 a10vso71 pump.

Radial load Fq max 2,300 N shaft center (X/2), axial Fax ±4,000 N. Bearing life L10h >20,000 hours Δp=280 bar, nnom. Mounting torque 60-180 Nm.

Performance Characteristic Curves

Flow-pressure curves confirm qV constancy at fixed Δp across swashplate range, volumetric losses 6-8%. Torque peaks proportionally at Vg max/280 bar. Power maintains linear scaling partial to full load.

Static pressure rise Δpmax hysteresis 3-6 bar typical. Dynamic stroking response 50 ms against 220 bar, destroking 70 ms zero stroke. Efficiency ηges 92% optimal 150-250 bar range.

Size 71 Detailed Specifications

Parameter
Metric
Imperial
Displacement Vg max
71 cm