Danfoss 51C160 bent axis variable hydraulic motor

The 51C160 is a variable displacement, bent-axis, axial piston motor from Danfoss's Series 51 and 51-1 product family (originally developed under Sauer-Sundstrand and later Sauer-Danfoss branding). "Bent axis" refers to the internal architecture: the cylinder block sits at an angle relative to the drive shaft, rather than in line with it, which is what distinguishes this design from swashplate-style axial piston motors.

How the Bent Axis Design Works

The Core Mechanism

In a bent-axis motor, pistons reciprocate within a cylinder block that's tilted relative to the output shaft — typically at up to 32 degrees in Danfoss's H-series and Series 51 designs. As pressurized hydraulic fluid enters the cylinder bores, it pushes the pistons outward. Because the cylinder block is angled, that linear piston motion translates into rotational force at the shaft through connecting rods and a drive flange.

This geometry has a practical payoff: bent-axis motors generally tolerate higher pressures and speeds than swashplate motors of similar size, because the piston side-loading forces are lower. That's a major reason Danfoss positions the Series 51 and H1B families for demanding propel and winch applications rather than light-duty auxiliary functions.

Why "Variable Displacement" Matters

Fixed displacement motors deliver a constant torque-to-speed relationship — you get what the geometry gives you. A variable displacement motor like the 51C160 changes its effective piston stroke on the fly, which means:

High torque at low speed when displacement is large (useful for starting a heavy load or climbing a grade)

High speed at reduced torque when displacement is reduced (useful for transport speed on flat ground)

This is the same principle that lets a bulldozer crawl through a heavy cut at full torque, then shift into a faster travel mode without changing pumps or adding a mechanical transmission.

Typical Applications

The 51C160 shows up wherever a machine needs a compact, high-force rotary actuator paired with a variable-displacement hydrostatic pump. Common examples include:

Crawler and Track Drive Systems

Bulldozers, excavators, and other tracked machines utilize bent-axis motors, such as the 51C160, in closed-loop circuits to drive final drives. The wide displacement ratio allows the machine to dig at high torque and travel at a higher speed without requiring a separate gearbox to do all the work.

Winch and Hoist Drives

Because the motor can be commanded to shift its displacement, winch systems use it to control line speed and pulling force independently — fast payout under light load, slow and powerful retrieval under heavy load.

Rail and Wheel Drive Applications

Road-going and rail maintenance equipment often pairs the 51C160 with a variable pump in a closed hydrostatic loop to drive wheels or rail bogies, giving smooth, stepless variable speed control.

Road Construction Machinery

Pavers, milling machines, and similar equipment use bent axis motors for propel functions where operators need fine control at crawl speeds as well as adequate transport speed.

Control Options Explained

The Series 51 family, including the 51C160, is available with several control schemes. Understanding which one is fitted matters a great deal for diagnostics and parts ordering.

H2 Control (Two-Position, Hydraulic)

A directly operated hydraulic two-position control shifts the motor between two fixed displacement settings — essentially a "high range / low range" switch, often paired with a pressure compensator override (PCOR) for automatic downshifting under high load.

Proportional Controls (E1/E2, F1/F2)

These allow continuous variable displacement across the full range, commanded electrically or hydraulically, rather than a simple two-position jump. This is the control family of choice when an operator or controller needs smooth, stepless speed transitions.

N2 Control (Pressure Compensator)

A pressure compensator regulator automatically adjusts displacement to limit system pressure, protecting the motor and driveline from stalling or overload without operator intervention.

S1 and HZ Controls

Additional hydraulic control variants exist for specific OEM requirements; note that PCOR is not available with the HZ control, which is a detail that trips up a lot of aftermarket rebuilds if it's missed.

For more information on the 51C160 hydraulic motor, please visit https://www.baolilaihydraulic.com/product/.

Specifications

Selection Table

Q1: What causes premature failure in these motors?

A1: The most common culprits are fluid contamination beyond the rated ISO cleanliness code, sustained operation above rated case pressure or temperature, and control malfunctions that force the motor to run at full displacement under conditions that call for destroking.

Q2: How does it differ from a fixed-displacement motor of the same size?

A2: A fixed displacement motor delivers one torque/speed relationship for a given flow and pressure. The 51C160 can vary its displacement across a 5:1 range, letting a single motor cover both high-torque, low-speed and low-torque, high-speed conditions — reducing the need for a separate mechanical gearbox.

Q3: What is the price and delivery time of the 51C060 hydraulic motor?

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

Q4:How to purchase a 51C060 hydraulic motor?

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