Product Overview
The A6VM series bent-axis axial piston variable motors are a flagship product line within the Bosch Rexroth hydraulic transmission platform, classified as all-purpose high-pressure motors. Featuring a bent-axis design with axial tapered piston rotary groups, these motors are specifically engineered for hydrostatic drives in both open and closed circuits. Designed to fully comply with Rexroth A6VM Series 63 mounting and interface standards, these motors offer 100% direct interchangeability with original Rexroth units—enabling plug-and-play replacement without any管路 modifications or adapter plates, significantly minimizing downtime and retrofit costs.
The A6VM series covers a wide displacement range from 28 to 1000 cc/rev (including 28/55/80/107/140/160/200/250/355/500/1000 cc specifications). Through various variable control methods—electrical proportional, hydraulic proportional, and hydraulic two-point control—the displacement can be continuously adjusted from Vg max down to Vg min ≈ 0. Every unit undergoes 100% factory testing under simulated real-world working conditions, validating pressure, flow, volumetric efficiency, and control characteristics before shipment—ensuring reliable operation from the very first start.
Model Code Interpretation:
A6VM250HZ/63W2-VZB027B
A6VM – Series code: Bent-axis axial piston variable motor
250 – Displacement size: 250 cm³/rev
HZ – Control type: Two-point hydraulic control
63 – Series number: Series 63
W – Rotation direction and port configuration
2 – Design code
VZB027B – Specific control and configuration code
A6VM160HD1D/63W-VAB020B
A6VM – Series code: Bent-axis axial piston variable motor
160 – Displacement size: 160 cm³/rev
HD1D – Control type: Hydraulic proportional control (specific sub-type)
63 – Series number: Series 63
W – Rotation direction and port configuration
VAB020B – Specific control and configuration code
Technical Specifications (Bulleted List)
A6VM250HZ/63W2-VZB027B
Model: A6VM250HZ/63W2-VZB027B
Type: Bent-axis axial piston variable motor
Displacement: 250 cm³/rev
Nominal Pressure: 350 bar
Maximum Pressure: 400 bar
Maximum Speed: 3000 r/min
Control Type: HZ – Two-point hydraulic control
Housing Material: Cast iron
Operating Temperature Range: -25°C to +90°C
Medium: Mineral oil, synthetic hydraulic oil (viscosity 15–160 mm²/s)
Weight: Approx. 60 kg
A6VM160HD1D/63W-VAB020B
Model: A6VM160HD1D/63W-VAB020B
Type: Bent-axis axial piston variable motor
Displacement: 160 cm³/rev
Nominal Pressure: 350–400 bar (sizes 28–200: 400 bar/450 bar)
Maximum Pressure: 400–450 bar
Maximum Speed: Configuration dependent
Control Type: HD1D – Hydraulic proportional control
Housing Material: Cast iron
Operating Temperature Range: -25°C to +90°C
Medium: Mineral oil, synthetic hydraulic oil
Weight: Approx. 66 kg
Series General Parameters (A6VM Series 63) :
Displacement Range: 28–1000 cm³/rev (28/55/80/107/140/160/200/250/355/500/1000)
Sizes 28–200: Nominal pressure 400 bar / Peak pressure 450 bar
Sizes 250–1000: Nominal pressure 350 bar / Peak pressure 400 bar
Circuits: Open and closed circuits
Mounting: SAE standard flange mounting
Key Technical Advantages
1. 100% Direct Interchangeability – Zero Modification Required
The A6VM series is engineered to exact Rexroth A6VM Series 63 mounting and interface specifications, with identical dimensions, port locations, and shaft end configurations. End users can replace original units directly without any管路 modifications or adapter plates—transforming unplanned downtime into scheduled, rapid maintenance while significantly reducing spare parts procurement costs and equipment downtime losses.
2. Bent-Axis Design with High Power Density and Wide Control Range
The bent-axis (curved shaft) design with axial tapered piston rotary groups delivers exceptional power density. Displacement can be steplessly adjusted from Vg max down to Vg min ≈ 0, with a maximum adjustment range of Vmax/Vmin = 3.47. By eliminating gear-shifting mechanisms, smaller pumps can be used to achieve a wide speed range, significantly reducing system cost and space requirements.
3. High-Speed Capability with Long-Life Bearing System
Approved for very high-speed operation. Equipped with a compact, robust long-life bearing system featuring an excellent power-to-weight ratio, superior starting characteristics, and low moment of inertia. The wide bent-axis swivel range provides strong adaptability.
4. Multiple Control Options for Flexible Adaptation
A wide range of control options is available—electrical proportional control, hydraulic proportional control, and hydraulic two-point control (HZ) . For HZ control, the control oil is internally taken from the high-pressure side of the motor (port A or B), requiring a minimum operating pressure of 30 bar (435 psi) for reliable control. Optional attached flushing and boost pressure valves, as well as integrated or attached counterbalance valves, are available.
5. 100% Factory Testing Under Simulated Working Conditions
Every A6VM series unit undergoes rigorous factory testing under simulated real-world conditions, validating pressure, flow, volumetric efficiency, control response characteristics, and thermal performance across the full operating range. Test media match actual operating conditions, ensuring each unit is ready for immediate installation and reliable operation upon delivery—eliminating the risk of “dead on arrival” components.
6. Compact Design with Modular Architecture
The bent-axis compact design and high-strength bearing system deliver high power density and low moment of inertia, balancing long service life with fast dynamic response. Optimized hydraulic circuits and low-friction structures ensure high starting efficiency and smooth operation characteristics. Modular components support rapid maintenance and upgrades.
Application Areas
The A6VM series variable motors are widely deployed across the following industries and equipment types:
Construction Machinery: Excavators, rotary drilling rigs, cranes, loaders
Road Construction Equipment: Rollers, asphalt pavers
Metallurgical Industry: Rolling mill hydraulic stations, forging equipment
Mining Equipment: Underground equipment, mining machinery
Marine & Shipbuilding: Marine equipment, deck machinery
Specialty Vehicles: Municipal vehicles, waste collection trucks
Industrial Equipment: Plastic injection molding machines, ceramic and refractory presses
Petrochemical: Petroleum machinery, chemical equipment
Specific model applications include:
Rotary drilling rigs: A6VM107HA2T/63W-VAB010, A6VM160HA2T/63W-VAB020
Cranes: A6VM160EP2D/63W-VZB010FPB, A6VM160HD1D/63W-VAB010A
Expert Maintenance Tips
1. Hydraulic Fluid Cleanliness Management
The A6VM series utilizes bent-axis axial piston designs with minimal clearances between pistons and cylinder bores, making them highly sensitive to fluid contamination. It is recommended to install filters with ≤10μm filtration rating, maintaining fluid cleanliness to ISO 4406 19/17/14 or better. Never use degraded or substandard hydraulic fluids.
2. HZ Two-Point Hydraulic Control Tuning (A6VM250HZ)
For HZ control, the control oil is internally taken from the high-pressure side of the motor (port A or B). To ensure reliable control, the operating pressure must be at least 30 bar (435 psi) . During commissioning, verify that system pressure meets this requirement; otherwise, control response will be unreliable.
3. Air Bleeding and Pre-filling Before Start-up
Always bleed air from the motor housing via the highest vent port before initial start-up or after extended shutdown periods to prevent cavitation damage. Ensure the motor housing is completely filled with hydraulic fluid prior to starting.
4. Coupling Alignment Requirements
Maintain shaft alignment within 0.05 mm concentricity and 0.5° angular deviation between the drive shaft and the load shaft. Excessive misalignment will lead to premature bearing wear and shaft seal leakage. The use of flexible couplings is recommended to compensate for minor installation deviations.
5. Case Drain and Backpressure Control
Ensure the case drain line is unrestricted with no flow restrictions. Excessive case backpressure will cause shaft seal damage and premature bearing failure. The drain line should return directly to the reservoir, not in parallel with the return line.
6. Periodic Inspection and Maintenance
Inspect shaft seals for leakage and listen for abnormal operating noise every 1,000 operating hours or every 6 months (whichever comes first). If reduced volumetric efficiency or insufficient output torque is observed, timely overhaul of the piston assembly and valve plate is recommended.
