Danfoss MMV series axial piston variable hydraulic motor

The MMV series is a medium-power, variable-displacement axial piston motor built on the same rugged platform as Danfoss's fixed-displacement Series 40 motors. Where the fixed units deliver a constant output relationship between flow in and speed/torque out, the MMV motor can change its displacement on the fly — typically through a trunnion-mounted, spring-and-pressure-actuated swashplate — letting a single motor cover a range of speed and torque combinations instead of just one fixed point.

In practical terms, that means the MMV can start a load with high torque at low speed, then shift toward higher speed and lower torque as conditions change, without swapping components or adding a second motor. That flexibility is why it shows up so often in fan drives, where cooling demand swings constantly with engine load and ambient temperature.

Key Design Features

Rigid cast-iron housing for durability in dirty, high-vibration mobile environments

Parallel axial piston/slipper design riding against a swashplate, a proven layout shared across much of Danfoss's mobile motor lineup

Variable displacement control, commonly via a trunnion-style swashplate actuator, allows the effective displacement to shrink or grow under changing pressure conditions

Displacement range in the roughly 35–46 cm³ (2.14–2.80 in³) family, matching the M35/M44/M46 fixed-displacement counterparts

Pressure capability rated up to roughly 345 bar (5,000 psi) in standard configurations

Compatibility with both open and closed-loop circuits, depending on the control and porting configuration ordered

How the MMV Series Works

The Core Mechanism

Like other axial piston motors in the Danfoss lineup, the MMV uses a cylinder block full of pistons riding against a tilted swashplate. Hydraulic fluid entering the motor pushes the pistons, which in turn rotate the cylinder block and output shaft. The torque produced is proportional to the pressure differential across the motor; the speed is proportional to the flow rate feeding it.

What sets the MMV apart is that the swashplate angle isn't fixed. A control mechanism — usually spring-biased and modulated by system pressure — shifts the swashplate angle in response to operating conditions. Tilt the swashplate further, and displacement increases, which raises torque capacity but lowers speed for a given flow. Reduce the angle, and the displacement drops, favoring speed over torque. This is the same basic principle used in larger Danfoss variable motors like the H1B bent-axis line, just packaged for the medium-power Series 40 frame size.

Typical Control Options

Variable motors in this class are generally available with a few standard control philosophies:

Pressure-compensated control, which automatically de-stroks the motor as system pressure climbs past a set point, protecting the circuit and the prime mover from stalling under heavy load

Two-position or multi-position control, switching between discrete displacement settings rather than modulating continuously

Manual or fixed-percentage override, used in simpler machine architectures where full automatic control isn't needed

The right choice depends heavily on the application's duty cycle — a fan drive with rapidly shifting cooling demand behaves very differently from a winch or auger that mostly runs at one or two set points.

Common Applications

Fan Drives

This is arguably the MMV's signature application. Engine cooling fans in construction, agricultural, and forestry equipment don't need constant speed — they need just enough airflow for current conditions, and no more, since over-driving a fan wastes horsepower and fuel. A variable-displacement motor like the MMV lets the fan speed track cooling demand rather than running flat-out all the time, which is a meaningful efficiency gain over a fixed-displacement setup.

Mobile and Off-Highway Equipment

Wheel loaders, agricultural machinery, and material-handling equipment use motors from this family in various propel and auxiliary functions where a machine needs to trade torque for speed, depending on load — climbing a grade versus traveling on flat ground, for instance, or a loader bucket working under heavy resistance versus light material.

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

Specifications

Selection Table

Q1: What displacement sizes are available in the MMV series?

A1: The family generally spans roughly 35–46 cm³ (2.14–2.80 in³), matching the M35, M44, and M46 designations depending on the specific model.

Q2: What industries commonly use MMV motors?

A2: Construction, agriculture, forestry, and material handling are the most common sectors, largely because these machines rely heavily on engine-driven cooling fans and variable-demand hydrostatic functions where a variable-displacement motor pays for itself in efficiency.

Q3:How to purchase an MMV hydraulic motor?

A3: You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.

Q4:What is the price and delivery time of the MMV hydraulic motor?

A4: The specific price and delivery time will be provided based on the specific model you provide.