Product Overview
The HRR057BLS2520NNA3S1N4A1NAAANNNNNN is a Sauer-Danfoss (now part of Danfoss Group) Series 45 Frame H swashplate-type axial piston variable displacement pump with a displacement of 57 cm³, purpose-built for open-circuit hydraulic systems in mobile machinery. The “RR” suffix denotes right-hand (clockwise) rotation. Featuring an SAE-B mounting flange, this Frame H pump is more compact and lighter than its Frame G counterpart, enabling direct replacement of SAE-B interface Frame F (74/90 cm³) pumps without adapters.
Manufactured to original Sauer-Danfoss specifications with guaranteed drop-in interchangeability, this pump requires no modification to mounting interfaces, spline connections, or port positions. Every unit undergoes 100% simulated working-condition dyno testing prior to shipment, including rated pressure cycling, displacement response verification, and leakage inspection, ensuring volumetric efficiency, pressure stability, and dynamic response meet OEM-equivalent standards.
Technical Specifications
Model: HRR057BLS2520NNA3S1N4A1NAAANNNNNN
Series: Sauer-Danfoss Series 45 (Frame H)
Type: Swashplate axial piston variable displacement pump (open circuit)
Displacement: 57 cm³/rev
Rated Working Pressure: 310 bar
Peak Pressure: 400 bar
Rated Speed: 2600 rpm
Minimum Speed: 500 rpm
Rotation: Clockwise (RR = right-hand)
Control Type: Load sensing (LS)
Mounting Flange: SAE-B
Shaft Configuration: Per model code
Weight: Approx. 30–35 kg (standard configuration)
Hydraulic Fluid: Mineral-based hydraulic oil (ISO VG 32–68)
Key Technical Advantages
1. Bimetallic Valve Plate with Optimized Flow Geometry
The HRR057 features a bimetallic valve plate with hydrodynamically optimized flow passages, effectively reducing pressure loss and flow pulsation during the porting cycle. Compared to conventional valve plate designs, this configuration maintains high volumetric efficiency across a wide range of pressures and speeds while significantly reducing operating noise. The cylinder block slides on the valve plate surface with a stable hydrodynamic lubrication film, minimizing metal-to-metal contact and extending the service life of the porting pair.
2. High-Capacity Tapered Roller Bearing System
The input shaft is supported by large-diameter tapered roller bearings capable of withstanding both the axial forces from swashplate displacement and radial loads from the drive end. Bearing preload is precisely calculated to maintain stable running clearance across the full speed range. A Viton lip seal effectively prevents shaft-end leakage, making the pump suitable for high-temperature and high-speed applications.
3. Adjustable Maximum Displacement Limiter
The pump is equipped with an adjustable mechanical maximum displacement limiter, allowing the maximum output flow to be restricted directly on the machine without modifying the hydraulic circuit. This feature is particularly valuable for applications requiring actuator speed matching or system overload prevention, simplifying commissioning and reducing circuit complexity.
4. Modular Auxiliary Mounting Pads
The housing provides SAE-A / SAE-B / SAE-C auxiliary mounting pads, enabling a tandem pump (such as a gear pump or a second piston pump) to be bolted directly to the main pump housing, forming a compact tandem assembly without separate support brackets. This modular design significantly reduces axial installation length, making it ideal for space-constrained mobile hydraulic systems.
5. Compact and Lightweight SAE-B Mounting Interface
Frame H utilizes an SAE-B mounting flange instead of the SAE-C flange found on Frame G, resulting in a significantly smaller and lighter pump package that mounts directly to SAE-B interface equipment without transition adapters. This design offers a distinct advantage in weight-sensitive mobile equipment such as telehandlers and wheel loaders.
Application Areas
The HRR057 series pump is widely used in the following equipment:
Telescopic handlers (Merlo, JCB, Manitou, Dieci)
Wheel loaders (Volvo, Caterpillar)
Municipal sweepers and snow removal equipment
Agricultural machinery hydraulic drive systems
Aerial work platforms (Haulotte, etc.)
Material handling equipment
Expert Maintenance Tips
Pre-Installation Checks: Verify that the pump shaft spline matches the drive end configuration before installation. Apply a light coating of grease to the spline surface. Ensure full contact between the mounting flange and the mounting pad. Never force the pump into position by tightening the fixing bolts, as this may cause abnormal bearing preload or housing deformation.
Oil Cleanliness Control: Series 45 pumps are sensitive to fluid contamination. System oil cleanliness should be maintained at ISO 4406 level 20/18/15 or better. Suction filters should be rated at 10 μm or finer; return-line filters at 10 μm or finer are recommended. Check suction line sealing before first start-up to prevent air ingress.
Start-Up and Break-In: During initial start-up, operate at low speed and low pressure for 10–15 minutes to purge air from the system and check all connections for leakage. Fill the pump case with clean hydraulic oil through the case drain port before starting to prevent dry-start damage to the porting pair.
Control Mechanism Maintenance: Periodically inspect load-sensing control line connections for tightness. No leakage or blockage should exist in the control circuit. If sluggish flow response or unstable pressure is observed, first inspect the control lines and pressure compensator valve. Once the maximum displacement limiter is set, avoid frequent adjustment unless necessary.
Case Drain Management: The case drain line must remain unrestricted; case pressure must not exceed 2 bar (gauge). Route the drain line directly to the reservoir below the oil level to avoid backpressure affecting pump operation.
