Danfoss Sauer FRR074 FRR090 Open Circuit Piston Hydraulic Pump,FRR090 Plunger Pump

Sauer Series 45 is a complete family of variable displacement, axial piston pumps for open 

circuit applications. Each frame within the Series 45 family is uniquely designed to 

optimize performance, size, and cost, matching the work function requirements of the 

demanding mobile equipment marketplace.

High performance

• Displacements from 25 cm³ - 147 cm³ [1.53 - 8.97 in3

/rev]

• Speeds up to 3600 rpm

• Pressures up to 310 bar [4495 psi] continuous, and 400 bar [5800 psi] peak

• Variety of control system options including load sensing and pressure compensated

• Through-drive capability for multi-circuit systems

• Range of mounting flanges, shafts, and porting options for ease of installation

Latest technology

• Customer-driven using quality function deployment (QFD) and design for 

manufacturability (DFM) techniques

• Optimized valve plates for maximum efficiency and quiet operation

• Computer-modeled castings to optimize inlet conditions for maximum pump speed

• Compact package size minimizing installation space requirements

• Heavy-duty tapered roller bearings for long life

• Single piece rigid housing to reduce noise and leak paths

• Integrated controls for high speed response and system stability

Reliability

• Designed to rigorous standards

• Proven in both laboratory and field

• Manufactured to rigid quality standards

• Long service life

• Significantly fewer parts

• No gasketed joints

• Robust input shaft bearings to handle large external shaft loads

• Integrated gauge ports for monitoring operating conditions

• Cranes

• Telescopic handlers

• Forklift trucks

• Wheel loaders

• Sweepers

• Backhoe loaders

• Forestry and agricultural machinery

• Fan drives

• Other uses

Series 45 Frame F pumps have a dual servo piston design with a cradle-type swashplate 

set in polymer-coated journal bearings. The bias piston increases swashplate angle. The 

servo piston decreases swashplate angle. At equal pressure, the larger diameter servo 

piston overpowers the bias piston. Nine reciprocating pistons displace fluid from the 

pump inlet to the pump outlet as the cylinder block rotates on the pump input shaft. 

The block spring holds the piston slippers to the swashplate via the slipper retainer. The 

cylinder block rides on a bi-metal valve plate optimized for high volumetric efficiency 

and low noise. Tapered roller bearings support the input shaft and a viton lip-seal 

protects against shaft leaks.

An adjustable one spool (PC only, not shown) or two spool (LS) control senses system 

pressure and load pressure (LS controls). The control ports system pressure to the servo 

piston to control pump output flow.