0510425025 AZPF-1X-008RQR20MB German original Rexroth gear pump

Frequently Asked Questions (FAQ)

1. Basic Parameters & Selection

Q: What is the displacement of this pump?

A: The geometric displacement is 8.0 cm³/rev.

Q: What is the maximum working pressure?

A: The maximum continuous working pressure is 250 bar, the maximum intermittent pressure is 280 bar, and the peak pressure is 300 bar.

Q: What is the rotation direction of the pump?

A: Clockwise rotation when viewed from the shaft end.

Q: What type of shaft does this model have?

A: This model (RQR) features a straight shaft with a keyway, unlike the tapered shafts common in other AZPF models.

2. Installation & Commissioning

Q: What are the critical installation requirements?

A:

• Shaft Alignment:​ The pump shaft and motor shaft must be connected via a flexible coupling. The radial runout should be less than 0.1 mm, and the angular error should be less than 1 degree. Rigid connections are strictly prohibited.

• Suction Conditions:​ The inlet line should be short and straight. The absolute pressure at the pump inlet must not fall below 0.7 bar. A flooded suction or boost pump is recommended for high-speed operation.

• Priming:​ The pump housing must be filled with clean hydraulic oil before the first start. Never run the pump dry.

Q: How should the case drain port be connected?

A: The case drain line must be connected directly, without restriction, and without a filter, back to the reservoir. The connection point should be below the fluid level but above the pump centerline. The backpressure in the drain line must not exceed 1 bar.

3. Operation & Troubleshooting

Q: The pump is very noisy. What is the cause?

A: Noise is usually caused by cavitation​ (whining) or aeration​ (crackling).

• Cavitation:​ Check for clogged inlet filters, oil viscosity that is too high, or a low oil level.

• Aeration:​ Check for air leaks in the suction line.

• Mechanical Noise:​ Check for misalignment or damaged bearings.

Q: How do I calculate the actual flow output?

A: Theoretical flow = 8.0 (cm³/rev) × Speed (rpm) / 1000. Actual flow will be 5-10% lower​ due to internal leakage (slip). If the flow drops more than 15%, the pump is likely worn.

Q: The pressure does not reach the rated value. What is the reason?

A: Possible causes include:

1. Internal Pump Wear:​ Increased clearance between the gear set and side plates.

2. System Leakage:​ Check other valves and actuators.

3. Low Motor Speed​ or incorrect relief valve setting.

4. Maintenance

Q: What type of oil is recommended?

A: The use of ISO VG 32/46/68 mineral-based hydraulic oils (HL, HLP) is recommended. Other fluids (HFC, HFD, etc.) are permissible, but seal material compatibility must be verified.

Q: What is the required oil cleanliness level?

A: A cleanliness level of NAS Class 9 or cleaner​ is mandatory. This is critical for ensuring the long service life of the precision sliding bearings.

Q: Can I disassemble and repair the pump myself?

A: It is not recommended for critical applications. While seal replacement is possible, the installation of the sliding bearings and pressure-compensated side plates requires special tools and pressure testing. For most users, an exchange unit is safer.

Disclaimer:​ This data is based on standard Rexroth documentation for the AZPF series. Always refer to the official datasheet (RE 10 250) for your specific application and safety guidelines.