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. Through various variable control methods, 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 (Series 63) :
A6VM107EP2/63W-VAB017HPB
A6VM – Series code: Bent-axis axial piston variable motor
107 – Displacement size: 107 cm³/rev
EP2 – Control type: Electric proportional control, 24V, with HIRSCHMANN connector (without suppressor diode)
63 – Series number: Series 63
W – Rotation direction and port configuration
VAB017HPB – Specific configuration code (including flushing valve, boost-pressure valve options)
A6VM250HA1/63W1-VZB020A
A6VM – Series code: Bent-axis axial piston variable motor
250 – Displacement size: 250 cm³/rev
HA1 – Control type: Automatic control, high-pressure related, with minimum pressure increase Δp ≤ approx. 10 bar
63 – Series number: Series 63
W1 – Rotation direction and port configuration
VZB020A – Specific configuration code
Technical Specifications
A6VM107EP2/63W-VAB017HPB
Model: A6VM107EP2/63W-VAB017HPB
Type: Bent-axis axial piston variable motor
Displacement: 107 cm³/rev
Rated Pressure: 400 bar (sizes 28–200: 400 bar)
Maximum Pressure: 450 bar
Maximum Speed (at Vg max): 3550 r/min
Maximum Speed (at Vg < Vg max): 5600 r/min
Maximum Inlet Flow (at nmax): 380 L/min
Shaft Torque (Δp=400 bar): 681 Nm
Control Type: EP2 – Electric proportional control, 24V
Weight: Approx. 47 kg
Housing Material: Cast iron
Medium: Mineral oil, synthetic hydraulic oil
Operating Temperature Range: -25°C to +90°C
A6VM250HA1/63W1-VZB020A
Model: A6VM250HA1/63W1-VZB020A
Type: Bent-axis axial piston variable motor
Displacement: 250 cm³/rev
Rated Pressure: 350 bar (sizes 250–1000: 350 bar)
Maximum Pressure: 400 bar
Maximum Speed (at Vg max): 2700 r/min
Maximum Speed (at Vg < Vg max): 3600 r/min
Maximum Inlet Flow (at nmax): 675 L/min
Shaft Torque (Δp=350 bar): 1391 Nm
Control Type: HA1 – Automatic control, high-pressure related (with minimum pressure increase)
Weight: Approx. 90 kg
Housing Material: Cast iron
Medium: Mineral oil, synthetic hydraulic oil
Operating Temperature Range: -25°C to +90°C
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 design with axial tapered piston rotary groups delivers exceptional power density. Displacement can be steplessly adjusted from Vg max down to Vg min ≈ 0. 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
The A6VM series offers a wide range of control options—EP2 electric proportional control (24V), HA1 high-pressure related automatic control, HD hydraulic proportional control, HZ hydraulic two-point control, EZ electric two-point control, and more. The HA1 control requires no external pilot oil supply—it automatically adjusts displacement based on the high-pressure side pressure of the motor, enabling constant torque/power control and simplifying system design. The EP2 electric proportional control supports remote precision displacement adjustment with rapid response.
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, with optional flushing and boost-pressure valves available.
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
Agricultural Machinery: Tractors, combine harvesters
Specialty Vehicles: Municipal vehicles, waste collection trucks
Industrial Equipment: Injection molding machines, presses
Specific model applications include:
A6VM107EP2/63W-VAB017HPB: Medium excavators, rotary drilling rig power head systems
A6VM250HA1/63W1-VZB020A: Large crane hoisting mechanisms, large roller travel drives
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. EP2 Electric Proportional Control Tuning (A6VM107EP2)
The EP2 control operates at 24V with a HIRSCHMANN connector (without suppressor diode). Before wiring, verify that the control system output voltage matches the coil specifications (24V) to avoid coil burnout from voltage mismatch or sluggish control response. The control signal is current-based; PWM regulation is recommended.
3. HA1 High-Pressure Related Automatic Control Tuning (A6VM250HA1)
The HA1 control is an automatic control, high-pressure related type with minimum pressure increase Δp ≤ approx. 10 bar. No external pilot oil source is required—displacement is automatically adjusted based on the motor high-pressure side pressure. For size 250 and above HA1 controls, note that pilot oil supply at port X requires an external pressure of pmin = 30 bar (pmax = 100 bar). To avoid pilot pressure build-up, port X should be relieved to the reservoir.
4. 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.
5. 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.
6. 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.
7. 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.
