Tonkee Machinery 로고
1. What type of hydraulic pump is the Rexroth A4VG Series?
The Rexroth A4VG Series is a line of high-pressure variable displacement axial piston pumps (variable piston pumps) engineered for heavy-duty mobile and industrial hydraulic systems. Designed by Bosch Rexroth, they feature a robust bent-axis design (distinct from swashplate designs) for superior torque transmission, 고효율, and exceptional durability—ideal for applications demanding precise flow control, extreme pressure resistance, and reliability in harsh operating environments.
2. What are the key design features of the A4VG Series?
- Bent-Axis Technology: The piston cylinder block is angled relative to the drive shaft (bent-axis design), enabling higher power density, smoother operation, and better resistance to shock loads compared to swashplate pumps.
- Variable Displacement: Adjusts displacement (0–100% of nominal) dynamically via control mechanisms to match system flow/pressure demands, optimizing energy efficiency.
- High-Pressure Capacity: Engineered for ultra-high operating pressures, suitable for heavy-load applications.
- Modular Design: Supports multiple control options, mounting configurations, and accessory integrations (e.g., auxiliary pumps, sensors) for versatile system adaptation.
- Wear-Resistant Components: Hardened steel piston-cylinder pairs, diamond-lapped surfaces, and robust bearings ensure long service life under high stress.
3. What sub-series and displacement ranges are available in the A4VG Series?
The A4VG Series covers a wide displacement spectrum (typically 28–180 cm³/rev) with dedicated sub-series for different flow/power needs:
- Small Displacement: A4VG28, A4VG40 (28–40 cm³/rev) – for medium-load mobile equipment (e.g., small excavators, skid-steer loaders).
- Medium Displacement: A4VG56, A4VG71, A4VG90 (56–90 cm³/rev) – versatile for both mobile (wheel loaders, cranes) and industrial (hydraulic presses) systems.
- Large Displacement: A4VG125, A4VG140, A4VG180 (125–180 cm³/rev) – for heavy-duty applications (mining trucks, large excavators, offshore machinery).
4. What control modes are offered for the A4VG Series?
Rexroth provides multiple control options to suit diverse system requirements:
- Pressure-Compensated Control (PC): Automatically reduces displacement when system pressure reaches the set limit (prevents overpressure).
- Load-Sensing Control (LS): Adjusts displacement based on actual load demand (minimizes energy loss, ideal for mobile machinery).
- Electro-Proportional Control (EP): Precise flow/pressure regulation via electrical signals (for automated industrial systems).
- Dual-Control Modes (e.g., PC + LS): Combines pressure protection and load adaptation for complex applications.
- Torque-Limiting Control (TL): Prevents the pump from exceeding maximum torque output (protects the drive system).
5. What are the core performance specifications of the A4VG Series?
| Parameter | Typical Range (varies by model) |
|---|---|
| Nominal Displacement | 28–180 cm³/rev |
| Maximum Working Pressure | 40 MPA (continuous); 45 MPA (short-term peak) |
| 속도 범위 | 800–2800 rpm (minimum: 800 rpm to avoid cavitation; maximum: 2800 rpm for large-displacement models) |
| Output Flow | Calculated by: Flow (L/분) = Displacement (cm³/rev) × Speed (RPM) ÷ 1000
Example: A4VG90 at 2000 rpm → 90 × 2000 ÷ 1000 = 180 L/분 |
| Volumetric Efficiency | ≥ 95% (under rated pressure/speed) |
| Total Efficiency | ≥ 90% (combines volumetric and mechanical efficiency) |
| Control Response Time | ≤ 0.3 seconds (for rapid adaptation to system changes) |
6. What hydraulic fluids are compatible with A4VG pumps?
- Recommended: Mineral-based hydraulic oils (ISOS VG 32, VG 46, or VG 68) with viscosity 15–46 cSt (optimal: 20–30 cSt).
- Compatible Alternatives: Synthetic hydraulic oils (PAO, ester-based) and biodegradable oils (for eco-sensitive applications like agriculture or marine use).
- Restrictions: Avoid oils with particle contamination > 10 μm, water content > 0.1%, or incompatible additives (refer to Rexroth’s fluid compatibility manual).
7. What applications are the A4VG Series pumps suitable for?
They excel in high-pressure, heavy-duty hydraulic systems requiring precision and durability:
- Mobile Machinery: Excavators, wheel loaders, mining trucks, hydraulic cranes, forestry equipment, and agricultural harvesters.
- Industrial Machinery: Heavy-duty hydraulic presses, metal forming equipment, marine propulsion systems, and offshore drilling rigs.
- Specialized Systems: Tunnel boring machines, waste compactors, and large-scale material handling equipment.
8. What maintenance is required for A4VG Series pumps?
- Oil Filtration: Use a ≥ 10 μm precision oil filter (Rexroth recommends R9280 series filters); replace filters every 2000–2500 operating hours.
- Fluid Maintenance: Monitor oil temperature (10–60°C optimal) and replace hydraulic oil every 5000–8000 hours (or sooner in dusty/extreme conditions).
- Component Inspection: Check shaft seals, O-rings, and piston packs quarterly for leaks; inspect bent-axis joints and bearings for wear at 10,000–15,000 hours.
- Startup & Shutdown: Prime the pump with oil before startup to avoid dry friction; relieve system pressure before shutdown to protect seals and valves.
- Alignment Check: Ensure proper alignment between the pump and drive motor (misalignment causes premature bearing failure).
