A6VM160HA1T/63W Rexroth Bent Axis Motor 160cc 400Bar Variable Displacement

Product Overview

The A6VM Series variable displacement axial piston motor is a high-pressure hydraulic motor platform from Bosch Rexroth, widely deployed in mobile machinery and stationary equipment. The motor features an axial tapered piston rotary group of bent-axis design, suitable for hydrostatic drives in both open and closed circuits. The series covers displacements from 28 to 1,000 cm³/rev. Sizes 28 through 200 achieve a nominal pressure of 400 bar with peak pressure up to 450 bar, while sizes 250 through 1,000 operate at 350 bar nominal with 400 bar peak. The wide control range enables the variable motor to satisfy requirements for both high speed and high torque.

The specific models covered in this document — A6VM160HA1T/63W-VZB380A-SK and A6VM160HA2/63W-VAB020A-S — are both A6VM160 frame size configurations (160 cm³/rev displacement) within the Series 63 standard range. At maximum displacement, the A6VM160 achieves a nominal speed of 3,100 rpm, maximum inlet flow of 496 L/min, and output torque of 1,019 Nm at a pressure differential of 400 bar. These motors are manufactured to original Rexroth specifications with 100% drop-in interchangeability, requiring no modification to mounting interfaces, port positions, or hydraulic connections. Every unit undergoes 100% simulated operating condition testing at the factory, including rated pressure loading, volumetric efficiency verification, control response characterization, and seal integrity assessment prior to shipment.

Model code breakdown: A6VM160 — A6VM designates the bent-axis variable displacement motor series, 160 indicates a maximum displacement of 160 cm³/rev; HA1T and HA2 denote two different automatic high-pressure related control modes; 63W specifies the Series 63 standard range and mounting configuration; VZB380A and VAB020A define port locations, control valve body, and additional feature configurations; -SK and -S are special option identifiers.

Technical Specifications 

A6VM160HA1T/63W-VZB380A-SK:

• Series / Type: Rexroth A6VM bent-axis axial tapered piston variable motor, Series 63

• Maximum displacement: 160 cm³/rev

• Minimum displacement: 0 cm³/rev (Vg min = 0, steplessly adjustable to zero)

• Nominal pressure (continuous): 400 bar (40 MPa)

• Maximum pressure (intermittent): 450 bar (45 MPa)

• Maximum speed at Vg max: 3,100 rpm

• Maximum speed at Vg < Vg max: 4,900 rpm

• Maximum inlet flow: 496 L/min

• Output torque at Δp = 400 bar: 1,019 Nm

• Torque constant: 2.54 Nm/bar

• Control type: HA1T automatic high-pressure related control with hydraulic override (T-type), external X pilot port

• Control start pressure range: 80–350 bar (adjustable)

• HA1T control characteristic: displacement from Vg min to Vg max requires only approximately 10 bar pressure change

• Mounting: SAE flange mount

• Port configuration: VZB configuration, side ports

• Direction of rotation: Bidirectional

• Housing material: High-strength cast iron

• Approximate weight: 64 kg

A6VM160HA2/63W-VAB020A-S:

• Series / Type: Rexroth A6VM bent-axis axial tapered piston variable motor, Series 63

• Maximum displacement: 160 cm³/rev

• Minimum displacement: 0 cm³/rev (Vg min = 0, steplessly adjustable to zero)

• Nominal pressure (continuous): 400 bar (40 MPa)

• Maximum pressure (intermittent): 450 bar (45 MPa)

• Maximum speed at Vg max: 3,100 rpm

• Maximum speed at Vg < Vg max: 4,900 rpm

• Maximum inlet flow: 496 L/min

• Output torque at Δp = 400 bar: 1,019 Nm

• Torque constant: 2.54 Nm/bar

• Control type: HA2 automatic high-pressure related control, positive control (pressure-increase control)

• Control start pressure range: 80–350 bar (adjustable)

• HA2 control characteristic: displacement change requires approximately 100 bar pressure variation, suited for speed/torque modulation under heavy-load conditions

• Mounting: SAE flange mount

• Port configuration: VAB configuration, side ports

• Direction of rotation: Bidirectional

• Housing material: High-strength cast iron

• Approximate weight: 64 kg

A6VM Series displacement range (for reference):

• A6VM28: 28.1 cm³/rev

• A6VM55: 54.8 cm³/rev

• A6VM80: 80 cm³/rev

• A6VM107: 107 cm³/rev

• A6VM140: 140 cm³/rev

• A6VM160: 160 cm³/rev

• A6VM200: 200 cm³/rev

• A6VM250: 250 cm³/rev (nominal pressure 350 bar)

• A6VM355: 355 cm³/rev (nominal pressure 350 bar)

• A6VM500: 500 cm³/rev (nominal pressure 350 bar)

Key Technical Advantages

1. Bent-Axis Axial Tapered Piston Rotary Group Design
The A6VM160 employs an axial tapered piston rotary group of bent-axis design, transmitting piston force to the output shaft through the most direct path. This architecture achieves high mechanical efficiency with a short torque transmission path. Compared to swashplate-type variable motors, the bent-axis structure accommodates higher working pressures at equivalent displacement, while generating lower side forces between pistons and cylinder bores — reducing friction losses and wear rates in the running gear. Motor displacement is infinitely variable from Vg max to Vg min = 0. Output speed depends on pump flow and motor displacement, while output torque increases with the pressure differential between high-pressure and low-pressure sides and with increasing displacement.

2. Dual Automatic High-Pressure Related Control Options: HA1T and HA2
Both HA1T and HA2 are Rexroth automatic high-pressure related control modes. The core principle involves the controller internally measuring operating pressure at port A or B; upon reaching the set beginning of control, the controller automatically adjusts motor displacement for pressure-adaptive operation. The critical distinction between the two control modes lies in sensitivity:

• HA1T control: Motor displacement from Vg min to Vg max requires only approximately 10 bar pressure change for full stroke adjustment — highly responsive, ideal for applications requiring precise speed control with minimal load pressure fluctuation.

• HA2 control: Displacement change requires approximately 100 bar pressure variation, permitting speed/torque modulation within a 10 MPa working pressure range — more stable under heavy-load conditions where working pressure varies significantly, making it ideal for rotary drilling rig power head applications and similar heavy-duty use.

The HA1T variant additionally features hydraulic override control (T-type), whereby external pilot pressure at port X enables override intervention of the HA control function for greater system control flexibility. Control start pressure for both variants is adjustable within 80–350 bar.

3. Compact and Robust Bearing System with Long Service Life
The A6VM160 output shaft is supported by a heavy-duty bearing system designed for extended service life. The compact, robust construction achieves high power density within a limited envelope, with good starting characteristics and small swing torque. The motor offers a range of control device options including attached flushing and boost pressure valves or integrated/attached counterbalance valves, accommodating diverse system integration requirements.

4. Series 63 Platform Commonality and System Integration Advantages
The A6VM160 belongs to the Series 63 standard range and shares platform architecture and numerous components with other A6VM displacement sizes. The Series 63 design has been field-proven over decades of operation in mobile machinery and stationary equipment. Platform commonality delivers twofold engineering value: repair parts can be sourced from the same inventory across the platform, reducing spare parts management complexity; and reliability validation accumulated across extensive field applications transfers directly to specific models, enhancing fleet-level maintenance economics. The motor is suitable for both mobile and stationary applications, with a wide control range enabling the variable motor to satisfy requirements for both high speed and high torque.

Application Areas

• Rotary drilling rig power heads: The A6VM160HA2 series is among the most commonly used hydraulic motors for rotary drilling rig power heads, with HA2 control providing superior speed/torque modulation under heavy-load conditions

• Construction equipment: Hydraulic excavator swing drives, crawler dozer travel drives, wheel loader travel systems, vibratory roller travel drives

• Lifting and transport machinery: Truck cranes, port gantry cranes, forklift travel drives, loading/unloading machinery

• Mining machinery: Hydraulic supports, rock drills, roadheaders, crushers, hoists

• Agricultural machinery: Tractor hydraulic transmissions, combine harvester ground drives, implement suspension systems

• Petroleum and chemical equipment: Oil exploration and drilling equipment drives

• Marine industry: Deck machinery, windlass drives

• Industrial applications: Machine tool drives, winch and conveyor drives

Expert Maintenance Tips

1. Case Filling and Air Purging — The First Step Before Startup
Axial piston units must always remain filled with hydraulic fluid and purged of air during commissioning and operation. This requirement also applies after extended shutdown periods, as the axial piston unit may drain hydraulic fluid back to the reservoir through hydraulic lines. This is especially critical for “drive shaft upward” mounting positions, where thorough filling and venting are essential to prevent risk of dry running. Before startup, fill the case through the highest drain port until fluid overflows, then retighten.

2. Case Drain Line Configuration Requirements
Case drain from the motor housing must be routed to the reservoir through the highest drain ports (T1, T2). For combinations of multiple units, ensure that the respective case pressure limits of each unit are not exceeded. Where pressure differentials exist between unit drain ports, shared drain lines must be replaced to ensure that the minimum permissible case pressure of all connected units is not exceeded under any circumstances. If this cannot be achieved, separate drain lines must be installed. Under all operating conditions, the case drain line must terminate below the minimum oil level in the reservoir.

3. HA1T Control-Specific Commissioning Points
For the A6VM160HA1T model, the HA1T control requires only approximately 10 bar pressure change for displacement from Vg min to Vg max — control sensitivity is extremely high. During commissioning, pay particular attention to precise setting of the control start pressure (within the 80–350 bar range) to avoid abnormal displacement response due to setting deviation. The external X pilot control port should remain plugged when override control is not required. The control oil is internally taken from the high-pressure side of the motor (A or B). For reliable control, an operating pressure of at least 30 bar is required at A (B). If control operation is performed at an operating pressure below 30 bar, an auxiliary pressure of at least 30 bar must be applied at port G via an external check valve.

4. HA2 Control Advantages Under Heavy-Load Conditions
The A6VM160HA2 model is suited for heavy-load applications such as rotary drilling rig power heads. HA2 control permits speed/torque modulation within a 10 MPa working pressure variation range. By contrast, with HA1 control, the motor displacement from 0 to 100% requires only 10 bar pressure change; under heavy-load conditions (where working pressure variation far exceeds 1 MPa), motor displacement remains essentially constant, preventing effective speed/torque modulation. Therefore, for applications with significant load pressure fluctuation, HA2 control is recommended.

5. Fluid Cleanliness and Viscosity Management
The A6VM Series operates with micron-level clearances between pistons and cylinder bores and between the valve plate and cylinder block face. Systems must be equipped with filtration rated to ISO 4406 18/16/13 or better. Fluid viscosity should be maintained within the optimum range: at operating temperature, VG 46 or VG 68 viscosity grades are recommended, with VG 68 preferred for higher ambient temperatures. Replace filter elements at the first 500-hour interval, then every 1,000–2,000 hours or based on oil analysis results.

6. Installation Position and Vibration/Noise Reduction
Recommended installation positions are horizontal mounting or drive shaft horizontal orientation. For favorable noise characteristics, all connecting lines should be isolated with elastic elements, and installation above the reservoir should be avoided. Under certain installation conditions, effects on control characteristics can be expected: gravity, net weight, and case pressure may cause slight variations in control characteristics and altered response times. Tighten mounting bolts in stages to the specified torque value and re-check torque after 500 operating hours.

7. Restart Procedure After Extended Shutdown
If the motor has been idle for more than three months, manually rotate the output shaft to confirm freedom of movement, and inspect the case oil level and shaft seal for leakage before restarting. Extended shutdown can cause oil film drainage from piston-slipper interfaces, creating a dry-start risk. Before restarting, replenish clean hydraulic fluid through the case fill port and operate at low speed and reduced load for 10–15 minutes before returning to normal duty.