Bosch Rexroth A2FM A6VM A6VE hydraulic motors for Soilmec construction machinery 50740028 50760087 50760124 50760125 50760123 50760135

Soilmec machines don't move earth the way an excavator does. They apply enormous rotational torque to a drill string, kelly bar, or auger while simultaneously managing crowd force, hoist, and winch functions. Every one of those functions is powered hydraulically, and the motor is where hydraulic energy becomes usable mechanical rotation.

A2FM, A6VM, and A6VE — share the same fundamental architecture: bent-axis axial piston design. Understanding this shared foundation makes the differences between the three much easier to follow.

How Bent-Axis Axial Piston Motors Work

In a bent-axis motor, the cylinder block sits at an angle relative to the output shaft (typically around 25 to 40 degrees depending on the model). Pressurized hydraulic fluid pushes pistons within the cylinder block, and because the block is angled, that piston motion translates directly into rotational torque on the output shaft — with minimal side loading on the bearings compared to swash-plate designs.

This geometry gives bent-axis motors a few practical advantages that matter on a drilling rig:

Higher pressure ratings, since the design handles side loads well

Strong efficiency across a wide speed range

Compact size relative to the torque they produce

Durability under the shock loading typical of drilling and piling work

Fixed vs. Variable Displacement

This is where the three model families start to diverge in purpose.

A2FM is a fixed-displacement motor. Output speed and torque are directly proportional to flow and pressure, with no internal adjustment mechanism.

A6VM is a variable-displacement motor, meaning the swivel angle of the cylinder block can change, adjusting displacement on the fly.

A6VE is also variable-displacement, generally used in mobile and traction-type applications where a wide speed range from a single motor is essential.

A2FM: The Workhorse Fixed-Displacement Motor

The A2FM series is Rexroth's fixed-displacement bent-axis motor, commonly found in Soilmec applications where a constant torque-to-flow relationship is exactly what's needed — winch drives, certain auger drive stages, and secondary rotation functions on multi-motor drive trains.

A6VM: Variable Displacement for the Main Rotary Drive

The A6VM series is where things get more interesting for a drilling rig's primary function: rotating the kelly bar or drill string. Because A6VM motors can vary displacement, they let a single motor deliver high torque at low speed for breaking through tough ground, then automatically shift toward higher speed and lower torque once the drill string is moving freely.

A6VE: Variable Displacement for Travel and Track Drive

The A6VE series shares the variable-displacement principle of the A6VM but is optimized for closed-loop travel circuits — think track drive motors on a crawler-mounted Soilmec rig. When the rig needs to reposition itself around a job site, the A6VE motor manages the transition between high-torque, low-speed crawling (useful on soft or uneven ground) and higher-speed travel on firmer surfaces.

Selecting the Right Motor for a Soilmec Application

Matching the right Rexroth motor to a specific function on a Soilmec machine comes down to a handful of practical questions:

1. Does the function need constant torque proportional to flow, or does it need to adapt across a wide speed/torque range? Constant relationship functions (many winch and auxiliary drives) point toward A2FM. Wide-range functions (main rotary drive, track propulsion) point toward A6VM or A6VE.

2. Is the application rotary (drilling head) or linear travel (track drive)? This typically separates A6VM from A6VE, since each series is optimized for its respective duty cycle.

3. What's the expected pressure and flow range? Displacement size within each family (measured in cm³ per revolution) needs to be matched to the rig's pump output and the torque targets of the specific drive.

4. What control signal does the rig's hydraulic system use? Hydraulic, electric proportional, or hydro-electric control options on A6VM/A6VE need to match the rig's existing control architecture.

Because Soilmec builds a wide range of machines — from compact micropiling rigs to large-diameter rotary drilling rigs — the specific motor size and control variant will differ significantly between models, even when the underlying Rexroth series is the same.

For more brand and equipment models, please visit https://www.baolilaihydraulic.com/brand/

Q1: What's the main difference between the A2FM, A6VM, and A6VE series?

A1: A2FM is fixed-displacement, meaning speed and torque scale directly with flow and pressure. A6VM and A6VE are variable-displacement, meaning the motor can adjust its internal geometry to shift the balance between torque and speed. A6VM is generally applied to rotary/drive functions, while A6VE is optimized for closed-loop travel circuits.

Q2: Why does Soilmec use motors from more than one Rexroth series on the same rig?

A2: Because a single rig has multiple hydraulic functions with very different requirements. A winch might only need a simple, linear torque-to-flow relationship (A2FM), while the main rotary drive needs to adapt across a wide torque/speed range within a single bore (A6VM), and the track drive needs the same adaptability applied to travel (A6VE).

Q3:What is the price and delivery time of the Rexroth A6VM/A6VE/A2FM motor for the Soilmec construction machinery？

A3: The specific price and delivery time will depend on the equipment model or specific product model you provide.

Q4:How to purchase a Rexroth A6VM/A6VE/A2FM motor for the Soilmec construction machinery?

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