Bosch Rexroth A6VM28 axial piston variable hydraulic motor

The Bosch Rexroth A6VM28 is a variable displacement axial piston motor with a swashplate design. This mature and reliable architecture is known for its high power density and high efficiency.

Axial Piston Swashplate Mechanism

The cylinder block contains several pistons arranged axially around a central drive shaft. These pistons move against a tilted plate – the swashplate. As the cylinder block rotates, the swashplate angle causes the pistons to reciprocate within their bores. The precise timing of this reciprocation with the motor's porting produces smooth, continuous rotary motion from pressurized hydraulic fluid. The A6VM28 provides a displacement of 28 cm³ per revolution at maximum setting, offering a balance of torque and speed.

Variable Displacement for Ultimate Control

The key feature is its variable displacement. The swashplate angle is adjustable hydraulically, even during operation. A smaller swashplate angle shortens the piston stroke, reducing the motor's displacement. This enables:
• Higher output speeds at the same input flow
• Precise speed control without changing pump output
• "Horsepower matching," optimizing power draw to the load requirement and saving energy

Key Performance Characteristics and Engineering Specifications

The A6VM28 is engineered to meet the rigorous standards of the Rexroth A6VM series, renowned for its durability. Key specifications and features include:

Maximum Operating Pressure: Up to 450 bar (6,525 psi) continuous, providing exceptionally high power density.

High Torque Output: Delivers high starting and running torque directly from the shaft, often reducing or eliminating the need for gear reduction.

Excellent Overall Efficiency: Achieves high volumetric and hydro-mechanical efficiency (>90% in optimal ranges), minimizing heat generation and energy loss.

Robust Bearing Design: Designed to withstand substantial radial and axial loads, making it suitable for direct mounting in harsh environments.

Primary Application Sectors: Where the A6VM28 Excels

This motor is not intended for light-duty use. Its design serves industries where equipment is capital-intensive and downtime is extremely costly.

Mining and Tunneling Machinery

In winches, conveyor drives, and cutter heads, the A6VM28 delivers relentless torque and resistance to shock loads common in mineral extraction. Its sealed housing protects against contaminated environments.

Marine and Offshore Technology

It powers deck machinery (winches, windlasses), propulsion systems for workboats, and stern drives. Corrosion-resistant options and reliable performance during continuous operation are essential in these applications.

Heavy-Duty Mobile Equipment

From tracked vehicle travel drives and swing drives in material handlers to main propulsion in forest harvesters, this motor provides the mobile power required.

Selection and Integration: Critical Considerations for System Design

Specifying an A6VM28 involves more than matching a datasheet. Expert integration is essential.

Hydraulic Circuit Configuration

The motor is typically integrated into a closed-loop hydrostatic transmission circuit, paired with a variable displacement pump such as a Rexroth A4VG or A10VG. This setup requires an integrated charge pump and flush valve circuit for cooling and lubrication. Proper sizing of these ancillary components is crucial for longevity.

Control Modalities: HD, EP, or DA?

The A6VM28 is available with different control types for the swashplate:

HD (Hydraulic Control): Proportional control via an external hydraulic pilot signal.

EP (Electro-Proportional Control): Enables seamless integration with modern PLCs and control systems for precise electronic control.

DA (Dual Control): Allows two independent control methods, providing redundancy and flexibility.

Maintenance and Longevity: Ensuring Decades of Service

Preventive maintenance is essential to achieve the motor's potential 20,000+ hour service life.

1.Fluid Cleanliness: This is the most important factor. Adherence to ISO 4406 cleanliness codes (typically 18/16/13 or better) is mandatory.

2.Optimal Temperature Range:​ Maintain hydraulic oil between 40°C and 60°C. Use heat exchangers to prevent overheating, which degrades seals and fluid.

3.Regular Fluid Analysis:​ Scheduled oil sampling can predict internal wear (e.g., from pistons or the cylinder block) long before a failure occurs.

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Specifications

Selection Table

Q1: How does the "brake" function work on models with an integral brake?

A1:Many A6VM models offer an optional spring-applied, hydraulically released parking brake. When system pressure is removed, internal springs engage a multi-disc brake pack onto the shaft. Pressure must be applied (typically to a separate port) to release the brake before the motor can turn. This is a critical safety feature for holding loads.

Q2:What are common failure modes, and how can they be prevented?

A2: The most common failures are due to contamination (leading to wear of the valve plate/piston interface) and cavitation (often from restricted inlet flow or high viscosity). Prevention is strict adherence to filtration standards, ensuring proper charge pressure, and using the correct viscosity fluid for the operating temperature.

Q3: What is the price and delivery time of the A6VM28 hydraulic motor?

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

Q4:How to purchase an A6VM28 hydraulic motor?

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