The Baile Hydraulic A4VG series axial piston variable displacement pump is a high-performance hydraulic power component specifically designed for closed-circuit hydrostatic transmission systems. Built on a robust swashplate axial piston structure, the A4VG pump is engineered to deliver high pressure, high efficiency, and precise control under demanding working conditions.
It is widely applied in construction machinery, mining equipment, industrial drive systems, and heavy-duty mobile machinery. With its wide displacement range, strong load capacity, and flexible control options, the A4VG series has become one of the most important hydraulic pump solutions in modern high-power hydraulic systems.
1. Product Concept and Working Principle
The Baile Hydraulic A4VG pump is based on the axial piston swashplate principle. In this design, a set of pistons arranged in a circular cylinder block rotates with the drive shaft. The pistons reciprocate due to the angle of the swashplate, converting mechanical rotational energy into hydraulic energy.
The key feature of the A4VG is its variable displacement capability, achieved by adjusting the swashplate angle. When the swashplate angle increases, the displacement and flow output increase; when the angle decreases, the flow output reduces. When the swashplate passes through the neutral position, the flow direction reverses, making it ideal for hydrostatic drive systems requiring bidirectional movement.
Another important feature is the integrated charge pump (boost pump), which maintains a constant replenishment of oil in the closed loop circuit. This ensures stable system pressure, prevents cavitation, and improves operational reliability.
The pump is also equipped with high-pressure relief valves, which protect the hydraulic system from overload conditions and sudden pressure spikes.
2. Technical Parameters of Baile Hydraulic A4VG Series
The A4VG series is available in multiple displacement sizes, allowing engineers to select the appropriate model based on power requirements, flow demand, and system design.
2.1 Displacement Range
The Baile Hydraulic A4VG series includes the following standard displacement sizes:
- A4VG 28 cm³/rev
- A4VG 40 cm³/rev
- A4VG 56 cm³/rev
- A4VG 71 cm³/rev
- A4VG 90 cm³/rev
- A4VG 125 cm³/rev
- A4VG 180 cm³/rev
- A4VG 250 cm³/rev
This wide displacement range enables the pump to cover small mobile machinery up to large industrial hydraulic systems.
2.2 Pressure Ratings
One of the most important performance characteristics of the A4VG pump is its high-pressure capability:
- Nominal operating pressure: up to 400 bar
- Maximum peak pressure: up to 450 bar
The pump is designed for continuous operation under high-pressure conditions, making it suitable for heavy-duty applications such as mining equipment and construction machinery.
2.3 Speed Range
The pump is designed for medium to high-speed operation:
- Minimum speed: approximately 500 rpm
- Rated operating speed: 1500 – 4000 rpm (depending on displacement)
- Maximum intermittent speed: up to 4500 rpm
The wide speed range allows compatibility with diesel engines, electric motors, and industrial drive systems.
2.4 Flow Output Characteristics
The flow rate of the A4VG pump is proportional to displacement and rotational speed. Typical maximum flow outputs include:
- A4VG 28: ~110 L/min
- A4VG 40: ~160 L/min
- A4VG 56: ~200 L/min
- A4VG 71: ~240 L/min
- A4VG 90: ~300 L/min
- A4VG 125: ~360 L/min
- A4VG 180: ~500 L/min
- A4VG 250: up to ~600 L/min
These high flow rates enable the pump to drive large hydraulic cylinders, hydraulic motors, and heavy load transmission systems.
2.5 Hydraulic Power Range
The output power of the A4VG pump depends on pressure and flow. Under rated operating conditions, the approximate hydraulic power ranges are:
- Small frame (28–56): 60 – 120 kW
- Medium frame (71–125): 120 – 250 kW
- Large frame (180–250): 250 – 400+ kW
This makes the A4VG suitable for both medium-duty mobile machinery and large-scale industrial hydraulic systems.
2.6 Control Types
The Baile Hydraulic A4VG pump supports multiple control methods, providing flexibility for system integration:
1. Mechanical Control (M)
Simple and reliable displacement adjustment using mechanical linkage.
2. Hydraulic Control (H)
Uses pilot hydraulic pressure to adjust swashplate angle.
3. Electro-Hydraulic Proportional Control (EP)
Allows precise electronic control of flow output, widely used in modern intelligent machinery.
4. Electric Displacement Control (EDC)
Provides direct electronic control of pump displacement for automated systems.
These control options make the A4VG highly adaptable to both traditional hydraulic systems and modern electro-hydraulic integrated systems.
2.7 Structural Features
- Closed-loop hydrostatic design
- Integrated charge pump (boost pump)
- High-pressure relief valves for both directions
- Swashplate axial piston structure
- High power density compact design
- Bidirectional flow capability
- High efficiency under variable load conditions
3. Application Fields of Baile Hydraulic A4VG Pump
The A4VG series is specifically designed for closed-loop hydrostatic transmission systems and is widely used in industries requiring high torque, high reliability, and precise speed control.
3.1 Construction Machinery Applications
Construction machinery is the most important application field for the A4VG pump.
Typical equipment includes:
- Excavators (travel drive and swing drive systems)
- Wheel loaders
- Bulldozers
- Road rollers
- Asphalt pavers
- Concrete pump trucks
- Drilling machines
In these applications, the A4VG provides:
- Smooth acceleration and deceleration
- High torque output at low speed
- Fast response to load changes
- Reliable bidirectional control
Its ability to handle frequent directional changes and shock loads makes it ideal for mobile construction machinery.
3.2 Mining and Heavy-Duty Equipment
Mining environments require hydraulic systems that can withstand extreme loads, dust, vibration, and continuous operation.
Typical applications include:
- Mining drilling rigs
- Underground loaders
- Crushing and screening equipment
- Heavy transport mining vehicles
- Material handling machines
Key advantages in mining applications:
- High pressure resistance up to 450 bar
- Strong anti-shock capability
- Stable continuous operation
- Excellent durability in harsh environments
The A4VG pump is widely used in modern mining machinery due to its reliability and long service life.
3.3 Metallurgy and Steel Industry
In steel production plants, hydraulic systems must operate under high temperature and continuous load cycles.
Applications include:
- Continuous casting machines
- Steel handling manipulators
- Rolling mill auxiliary systems
- Furnace loading and unloading systems
- Coil handling equipment
The A4VG provides stable flow control and high resistance to contamination, making it suitable for heavy industrial environments.
3.4 Industrial Hydrostatic Drive Systems
The A4VG is widely used in closed-loop industrial transmission systems where precise speed control is required.
Applications include:
- Hydraulic winch systems
- Conveyor belt drives
- Industrial testing equipment
- Material transport systems
- Track-driven industrial vehicles
In these systems, the pump enables smooth and efficient energy transfer with precise control over speed and direction.
3.5 Special Vehicles and Marine Systems
The compact design and strong performance of the A4VG make it suitable for special-purpose applications such as:
- Military engineering vehicles
- Port handling machinery
- Offshore hydraulic systems
- Marine auxiliary drive systems
- Emergency rescue equipment
These environments require reliable performance under variable load and harsh operating conditions.
4. Key Advantages of Baile Hydraulic A4VG Pump
The A4VG series offers a combination of technical and operational advantages:
- High working pressure up to 400–450 bar
- Wide displacement range (28–250 cm³/rev)
- Excellent power density
- Precise variable displacement control
- Multiple control options for system integration
- Suitable for closed-loop hydrostatic systems
- Strong resistance to shock loads and vibration
- High efficiency under variable operating conditions
- Long service life and low maintenance requirements
5. Engineering and System Design Benefits
From a system design perspective, the A4VG pump offers several important advantages:
- Simplifies hydrostatic transmission system design
- Reduces need for external directional valves
- Improves energy efficiency in mobile machinery
- Enhances controllability of hydraulic drive systems
- Supports intelligent electro-hydraulic integration
Its modular design allows engineers to adapt it to different machine types without major redesign of hydraulic architecture.
6. Conclusion
The Baile Hydraulic A4VG axial piston variable displacement pump is a high-performance hydraulic solution designed for demanding closed-loop hydrostatic transmission systems. With its wide displacement range, high-pressure capability, flexible control options, and excellent durability, it has become a core component in modern construction machinery, mining equipment, industrial drives, and special-purpose hydraulic systems.
Its ability to deliver stable hydraulic power under extreme conditions, combined with precise flow control and bidirectional operation, makes it one of the most reliable and widely used pump series in the global hydraulic industry.
For engineers and equipment manufacturers seeking a balance of performance, efficiency, and durability, the A4VG series remains a proven and highly effective solution.
