Rexroth A6VM Bent Axis Variable Displacement Hydraulic Motor: The Definitive Guide to Smart Rotary Power, Variable Displacement Controls, OEM Replacements, and Spare Parts for Excavators, Road Rollers, and Heavy-Duty Drives in 2026

Author: Elephant Fluid Power Co., Ltd. | Updated: July 14, 2026 | Reading Time: 20 minutes

Quick Answer: If your equipment demands a hydraulic motor that automatically adapts its displacement to match the load — delivering high speed when unloaded and maximum torque when working hard — the Rexroth A6VM bent axis variable displacement hydraulic motor is the intelligent solution. Featuring infinitely adjustable displacement from Vg max down to Vg min = 0, the A6VM delivers 400 bar nominal pressure (450 bar peak) across 11 sizes from 28 to 1,000 cm³, with six control options including the industry-favorite HA (high-pressure-related automatic control) that automatically modulates displacement based on working load. Elephant Fluid Power Co., Ltd. manufactures complete A6VM motors in all sizes and all control configurations and over 1,300 types of 100% interchangeable spare parts — cylinder blocks, piston assemblies, spherical valve plates, swivel angle control devices, drive shafts, and seal kits — delivering OEM-equivalent performance at 50-75% lower cost with same-day shipping from stock. With nearly 20 years of manufacturing excellence, German CNC production equipment, and distribution to 80+ countries, Elephant Fluid Power provides the fair pricing, fine quality, fast delivery, and world-class service that equipment operators and rebuilders worldwide depend on.

1. What Is the Rexroth A6VM Bent Axis Variable Displacement Motor?

The Rexroth A6VM is a variable displacement axial piston hydraulic motor of bent-axis design, engineered to convert hydraulic fluid pressure and flow into intelligent, adaptive rotary mechanical power. While the A2FM (covered in our companion article) is a fixed-displacement bent-axis motor that always operates at its maximum displacement, the A6VM introduces a revolutionary capability: its displacement is infinitely adjustable from Vg max (maximum displacement, maximum torque, minimum speed) all the way down to Vg min = 0 (zero displacement, freewheeling). This variable displacement capability enables the motor to automatically adapt its torque-speed characteristic to match the demands of the application — a feature that delivers substantial efficiency gains, broader operating ranges, and elimination of mechanical gearboxes in many hydraulic drive systems.

The operating principle builds on the proven bent-axis architecture shared with the A2FM. A cylindrical barrel is mounted at a fixed angle to the drive shaft axis, containing precision pistons whose spherical ends engage with a spherical socket plate on the drive shaft. The critical difference is the swivel mechanism: the cylinder barrel assembly is mounted on a pivoting cradle that allows the swivel angle (and thus the effective piston stroke) to be adjusted. When the swivel angle is at maximum, the pistons achieve their full stroke, delivering maximum displacement and torque. When the swivel angle is reduced toward zero, the piston stroke decreases, reducing displacement and increasing the motor’s maximum achievable speed for a given flow rate. At zero swivel angle (Vg min = 0), the motor effectively freewheels with minimal internal drag.

This variable displacement capability is controlled by one of six control device options — from simple hydraulic two-point switching (HZ) to sophisticated electronic proportional control (EP) — but the most widely deployed and industry-favored is the HA (high-pressure-related automatic control), which requires no external control signals, sensors, or pilot lines. The HA control simply measures the working pressure internally and automatically adjusts the swivel angle to provide just the right amount of displacement for the current load — maximum displacement under heavy load, minimum displacement when cruising.

1.1 A6VM vs. A2FM: When Variable Displacement Matters

The choice between A6VM (variable) and A2FM (fixed) is one of the most important decisions in hydraulic drive system design. Understanding when each motor type is the optimal choice is essential:

Key Insight: The A6VM’s variable displacement eliminates the need for mechanical gear shifting in many applications. An excavator travel drive using an A6VM with HA control can accelerate rapidly at low displacement (high speed, low torque) and then automatically increase displacement as load builds when climbing a slope or pushing into material — all without any gearbox or operator intervention. This “intelligent” torque-speed adaptation is the primary reason the A6VM dominates mobile equipment drive applications.

1.2 Two Series, One Platform: A6VM Series 63 and Series 65

The A6VM is produced in two series with overlapping size ranges to serve different application requirements:

Series 65 covers the most common mobile equipment sizes (55-200 cm³) with the highest pressure ratings (400/450 bar), while Series 63 extends the range to both the compact size 28 and the very large sizes 250-1000 for heavy industrial and mining applications.

2. Complete A6VM Technical Specifications: All 11 Displacement Sizes

2.1 Series 65: The Mobile Equipment Workhorse (55-200 cm³)

The Series 65 sizes represent the most widely specified A6VM motors for construction machinery, road equipment, and mobile cranes — all rated at 400 bar nominal and 450 bar peak pressure.

2.2 Series 63: Compact and Heavy-Duty Extremes (28, 250-1000 cm³)

2.3 Pressure Ratings Summary

3. Six Control Device Options: Matching Control Strategy to Application

The A6VM’s versatility is greatly expanded by its six control device families, each suited to specific application requirements. Selecting the correct control is essential for optimal system performance.

3.1 HA — Automatic High-Pressure Related Control (Most Popular)

The HA control is the most widely specified A6VM control for good reason: it is fully automatic, requires no external control signals or pilot lines, and delivers optimal efficiency across the entire operating range.

How HA Works: The control device internally measures working pressure at port A or B. At low pressure (light load), the motor operates at Vg min (minimum displacement, maximum speed). As pressure increases (load builds), the controller automatically swivels the motor toward Vg max, increasing displacement and torque. The displacement is continuously modulated between Vg min and Vg max depending on the actual load.

HA Control Example — Excavator Travel Drive: When the excavator is traveling on flat ground (low resistance), the HA control maintains the motor at Vg min (small displacement), allowing high travel speed with minimal flow consumption. When the excavator encounters a slope or soft ground (increased resistance → higher pressure), the HA control automatically increases displacement, providing more torque to maintain traction while the operator hasn’t touched any controls. This load-adaptive behavior improves fuel efficiency by 20-30% compared to fixed-displacement motors and eliminates the need for mechanical gearboxes.

3.2 HD — Hydraulic Control, Pilot Pressure Related

The HD control adjusts motor displacement proportionally to an external pilot pressure signal. A pilot pressure of 10 bar (HD1) or 25 bar (HD3) applied to the control port drives the motor from Vg min to Vg max.

Best For: Industrial machinery, test equipment, and systems where an external hydraulic control signal is readily available.

3.3 EP — Electric Proportional Control

The EP control provides infinite displacement adjustment via an electric current signal to a proportional solenoid. The motor displacement is directly proportional to the control current.

Best For: Automated systems, electronically controlled machinery, and applications requiring precise, programmable displacement control.

3.4 EZ — Electric Two-Point Control

The EZ control provides simple on/off displacement switching between Vg max and Vg min via a switching solenoid.

Best For: Applications requiring only two operating modes (e.g., transport speed vs. working speed) with minimal control complexity.

3.5 DA — Hydraulic Control, Speed Related

The DA control is specifically designed for travel drive applications. It combines speed-related control with an integrated travel direction valve that prevents undesirable swiveling during downhill travel.

Best For: Excavator and dozer travel drives where downhill braking behavior must be controlled.

3.6 HZ — Hydraulic Two-Point Control

The HZ control provides hydraulic on/off switching between Vg max and Vg min using an external pilot pressure signal.

Best For: Simple applications requiring hydraulic switching between high-torque and high-speed modes.

3.7 Control Device Selection Guide

4. Application Guide: Where A6VM Variable Motors Deliver Smart Rotary Power

4.1 Hydraulic Excavators — Travel and Swing Drives

The A6VM with HA control is the dominant motor choice for hydraulic excavator travel and swing drives, where its automatic displacement adaptation eliminates the need for mechanical transmissions while optimizing fuel efficiency.

4.2 Road Rollers and Compaction Equipment

The A6VM with HA2 control (gradual 100 bar pressure increase) is widely used in vibratory road rollers where smooth, vibration-isolated drive characteristics are essential.

4.3 Winch and Crane Drives

4.4 Concrete Pump Trucks

The A6VM powers various auxiliary drives on concrete pump trucks, including agitator drives, boom extension, and outrigger operation.

4.5 Mining, Forestry, and Agriculture

5. Complete Spare Parts Program: 100% Interchangeable with Original Rexroth A6VM

Elephant Fluid Power manufactures over 1,300 types of hydraulic motor spare parts with 100% dimensional and functional interchangeability with original Rexroth A6VM components. The A6VM’s variable displacement mechanism adds swivel angle control components not found in fixed-displacement motors, requiring specialized manufacturing expertise.

5.1 Core Spare Parts for A6VM Motors

5.2 Cost Comparison

6. Why Elephant Fluid Power? Fair Pricing, Fine Quality, Fast Delivery, World-Class Service

6.1 Fair Pricing: 50-75% Cost Savings

Elephant Fluid Power delivers OEM-equivalent A6VM motors and parts at 50-75% lower cost through manufacturing efficiency advantages in China’s advanced industrial corridor. For a contractor with 5 excavators using A6VM 107 travel motors, annual maintenance savings exceed $20,000-35,000.

6.2 Fine Quality: German CNC, Premium Materials

German CNC machining centers, CMM inspection, hydraulic test benches to 600 bar, and material laboratory ensure consistent quality. Every A6VM motor undergoes documented quality control with 1.5× pressure testing before shipment.

6.3 Fast Delivery

6.4 Service That Serves the World

Elephant Fluid Power provides motor selection assistance, control device selection guidance, troubleshooting support, 12-month warranty, and custom engineering.

“Very satisfied, good quality, fast delivery, saving a lot of costs for my motor.” — Martin, Europe

“Wow, it’s perfect. They sent the right accessories to me, and the installation is completely suitable.” — Filippo, Italy

7. How to Order: A6VM Motor and Parts Procurement Guide

7.1 Decoding the Rexroth A6VM Model Number

Common model numbers:

• A6VM107HA1/63W-VAB020 — Standard excavator travel motor

• A6VM80HA1/63W-VAB010 — Midi excavator travel/swing motor

• A6VM55HA2/63W-VAB020 — Road roller drive motor

• A6VM140HA1/63W-VZB010 — Large excavator travel motor

• A6VM160EP2/63W-VZB010 — Electronically controlled industrial drive

• A6VM200HA1/63W-VZB010 — Mining/heavy-duty drive motor

7.2 Contact Information

• Website: www.hydpumpparts.com

• Email: elephant@sjzhjsm.com

• Phone/WhatsApp: +86-180-3112-1586

• Address: No.398 Youyi Street, Xinhua District, Shijiazhuang City, Hebei, China

8. Frequently Asked Questions: A6VM Variable Motors and Parts

Q1: What is the difference between A6VM and A2FM motors?

A6VM is variable displacement (Vg max to Vg min=0 adjustable), while A2FM is fixed displacement (constant Vg). The A6VM’s variable displacement enables automatic torque-speed adaptation via controls like HA, eliminating the need for gearboxes in many applications. Choose A6VM for excavators, road rollers, and variable-load drives. Choose A2FM for concrete mixers, winches, and constant-speed drives where simplicity and lowest cost are priorities.

Q2: How does the HA control work on A6VM motors?

The HA (high-pressure-related automatic) control internally measures working pressure and automatically adjusts displacement — at low pressure (light load), the motor stays at Vg min for high speed; as pressure increases (heavy load), it swivels toward Vg max for more torque. This requires no external signals, sensors, or pilot lines. The HA1 variant responds over ~10 bar pressure increase; HA2 over ~100 bar for smoother transition.

Q3: What is the best replacement for a Rexroth A6VM motor?

Elephant Fluid Power manufactures complete A6VM motors in all 11 sizes (28-1000) with all six control types and 100% dimensional interchangeability with original Rexroth motors. All motors use German CNC-machined components, premium materials, and undergo 1.5× pressure testing. Buyers receive OEM-equivalent performance at 50-75% lower cost.

Q4: Which A6VM control type should I choose?

• For excavator travel/swing drives: HA (automatic, no external control needed)

• For road rollers: HA2 (gradual transition, smoother)

• For winch drives (lifting): HA (but NOT with Vg min start for safety)

• For electronically controlled systems: EP (proportional electric)

• For simple two-speed systems: EZ (electric on/off)

• For travel drives with downhill control: DA (speed-related with direction valve)

Q5: How much can I save by buying A6VM parts from Elephant Fluid Power?

Complete A6VM motors cost 65-70% less than original Rexroth — an A6VM 107 HA costs approximately $650-1,100 versus $2,000-3,500 OEM. An A6VM 160 costs $1,000-1,700 versus $3,000-5,000 OEM. Spare parts offer 65-75% savings. For a contractor with 5 excavators, annual maintenance savings exceed $20,000-35,000.

Q6: Does Elephant Fluid Power supply A6VM motors with all control types?

Yes. Elephant Fluid Power supplies A6VM motors with all control types: HA (HA1, HA2, HA.T3, HA.U1/U2, HA.R1/R2), HD (HD1, HD3, HD1D1, HD3D1), EP (EP1, EP2, EP5, EP6), EZ (EZ1, EZ2), DA (DA0, DA1, DA2), and HZ.

Q7: What is the warranty on Elephant Fluid Power A6VM motors and parts?

12-month warranty from shipment date against defects in materials and workmanship. Covers free replacement of defective components. Motors must be operated within published specifications.

Q8: Can Elephant Fluid Power supply parts for other motor brands?

Yes. Compatible parts for Rexroth (A2FM, A2FE, A10FM, A10VO motor, A4VG motor), Eaton, Parker, Kawasaki, Sauer, Linde, and other brands. Over 1,300 types of spare parts.

Q9: What is a BVD/BVE counterbalance valve and do I need one?

The BVD/BVE counterbalance valve is an optional safety device for A6VM travel drives (sizes 55-160). It prevents overspeeding when traveling downhill by automatically throttling return flow if pressure drops. We strongly recommend ordering the BVD with the motor for travel drive applications.

Q10: How do I order from Elephant Fluid Power?

Send motor model number or part description to elephant@sjzhjsm.com or WhatsApp +86-180-3112-1586. Quotations within 24 hours.

9. Technical Specifications Summary: A6VM Series at a Glance

About Elephant Fluid Power Co., Ltd.

Established in Shijiazhuang, Hebei Province, China, Elephant Fluid Power Co., Ltd. is a professional manufacturer and global supplier of hydraulic piston pumps, hydraulic motors, and over 1,300 types of 100% interchangeable spare parts. We produce Rexroth-compatible A6VM, A2FM, A2FE, A10VSO, A10VO, A11VO, A20VO, A4VG, A4VSO, A2FO, and A7VO series. Serving 80+ countries with fair pricing, fine quality, fast delivery, and world-class service.

Contact: www.hydpumpparts.com | elephant@sjzhjsm.com | +86-180-3112-1586