Sauer danfoss 51V060 variable displacement hydraulic motor

The Sauer Danfoss Series 51 is a family of bent-axis, variable displacement axial piston motors designed for demanding closed-circuit hydrostatic transmission applications.

Core Design Architecture

Bent-Axis Axial Piston Design

Unlike swashplate motors, the Series 51 uses a bent-axis configuration where the cylinder barrel is inclined at an angle relative to the drive shaft. This geometry produces several meaningful advantages:

Higher mechanical efficiency at elevated pressures

Greater tolerance to contaminated fluid due to the larger piston-to-bore clearance ratios

Excellent power density-the 51V060 delivers high torque from a compact envelope

More symmetrical radial loading on the shaft bearings, extending bearing life

The pistons themselves bear directly on a spherical piston-to-shaft interface, eliminating the slipper pad that swashplate designs require. For high-duty-cycle applications, this translates to longer mean time between overhauls.

Variable Displacement Mechanism

The displacement range of the 51V060 spans from minimum (approximately 20–25% of maximum) to full 60 cm³/rev, achieved by varying the angle of the rotating group relative to the output shaft. This is controlled by an internal servo piston acting on the cradle or yoke assembly.

The motor can be ordered with several control options:

Two-position control-shifts between minimum and maximum displacement via a solenoid signal

Proportional hydraulic control-continuously variable displacement via a pilot pressure signal

Electrohydraulic (EH) control-proportional displacement set by an electric command signal (typically 0–600 mA or similar), enabling integration with electronic control units (ECUs)

For most modern applications, the EH control option is preferred because it allows closed-loop speed or torque regulation through the machine's CAN-bus-connected controller.

Port Configuration and Case Drain

The 51V060 features SAE-flanged work ports (typically SAE B or SAE C, depending on the specific build code) and a case drain port that must be piped to the reservoir. Case drain flow carries heat and any internal leakage fluid away from the motor housing. Neglecting to connect or adequately size the case drain line is one of the most common installation errors and a leading cause of shaft seal failure.

Common Failure Modes and Troubleshooting

Loss of Torque or Speed

Symptoms: The motor produces less torque than expected, or the top speed is lower than specified.

Likely causes:

Internal leakage due to worn valve plate or piston/bore wear, check volumetric efficiency by measuring actual case drain flow vs. expected

Control system not commanding full displacement-verify pilot pressure or EH command signal

System charge pressure below specification, low charge pressure allows the motor to cavitate, dramatically reducing efficiency

Shaft Seal Leakage

Symptoms: Fluid weeping from the shaft area, often collecting on the output flange or gearbox input.

Likely causes:

Case drain back-pressure exceeding 3 bar

Shaft seal lip damage from contaminated fluid

Shaft runout due to misaligned or overloaded output coupling

Noise and Vibration

Symptoms: Hammering, grinding, or erratic speed fluctuation.

Likely causes:

Cavitation due to low charge pressure or restricted suction

Air ingestion through a loose case drain fitting or a low reservoir level

Worn or cracked cylinder block valve plate requires disassembly to confirm

Displacement Control Not Responding

Symptoms: Motor stays at minimum or maximum displacement regardless of the command signal.

Likely causes:

Failed solenoid or proportional valve in the control section

Contamination in the servo control circuit-the servo orifices are extremely small (0.4–0.8 mm) and block readily

Loss of pilot supply pressure to the control valve

For more information on the 51V060 hydraulic motor, please visit https://www.baolilaihydraulic.com/.

Specifications

Selection Table

Q1: For which type of applications is the 51V060 hydraulic motor most suitable?

A1: The 51V060 hydraulic motor is engineered for demanding mobile and industrial applications requiring substantial power in a compact package. It is ideally suited for tough environments in construction machinery, agricultural equipment, drilling rigs, and material handling systems.

Q2:What hydraulic fluid is recommended?

A2: Danfoss specifies mineral-based hydraulic oil meeting ISO VG 46 or VG 68 for most operating temperatures, with a viscosity range of 10–160 cSt at operating temperature and an optimum of 16–40 cSt. Some manufacturers also approve certain synthetic and biodegradable fluids — consult the current fluid compatibility chart in the Series 51 service manual.

Q3: What is the price and delivery time of the 51v060 hydraulic motor?

A3: The specific price and delivery time will be provided based on the specific model you provide.

Q4:How to purchase a 51v060 hydraulic motor?

A4:You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.