A4VG71EP2DM1/32L-NZF02F001DXS A4VG 40 56 71 90 125 High Pressure Hydraulic Oil Axial Piston Variable Pump

I. Technical Parameters
Core performance parameters
– Pump type: Axial variable piston pump, swash plate structure, right-rotating steering, suitable for high-pressure open hydraulic circuits, adopts electro-proportional + load sensitive compound control, supports displacement 0-71mL/r stepless adjustment, providing high-pressure stable oil supply for heavy-duty single/multiple actuators.
– Displacement and pressure parameters: Rated displacement 71 mL/r (estimated based on model “71”); Rated working pressure: 31.5 MPa, maximum allowable pressure: 35 MPa (for a duration of ≤10 seconds); Rated speed: 1500 r/min, maximum speed: 2000 r/min (short time ≤5 minutes).
– Flow and efficiency parameters: Maximum flow at rated speed is 106.5 L/min, and the variable range is continuously adjustable from 0 to 106.5 L/min. Volumetric efficiency ≥94%, total efficiency ≥86%; The flow regulation accuracy is ±1.5%, and the pressure control accuracy is ±0.2 MPa.
– Operating characteristics: Continuous operating oil temperature ≤85℃, rated working condition inlet vacuum degree ≤ 0.02MPa; Noise value ≤85 dB (measured at 1 meter); The fault-free operating life under rated conditions is ≥ 15,000 hours.
2. Structure and connection parameters
– Structural type: Swash plate axial plunger structure, integrating a double plunger cylinder body, an electric proportional variable swash plate, a return plate, and built-in dual high-pressure relief valves + oil replenishment valves; It adopts flange installation, is equipped with a high-efficiency oil suction filter screen and a pressure compensation valve, and supports dual regulation of hydraulic pilot and electrical proportional.
– Core material: The plunger is made of stainless steel 17-4PH (quenched and tempered, hardness HRC42-45); The cylinder block is made of alloy cast iron QT600-3 (aged treatment, hardness HB280-320). The swash plate is made of bearing steel GCr15 (quenched treatment, hardness HRC62-66). The sealing part is a combination of high-pressure resistant fluororubber and polytetrafluoroethylene (with a temperature resistance of ≤120℃).
– Connection specifications: The oil suction port (S) is a DN80 flange, and the oil outlet port (P) is a DN65 flange. The drive shaft is spline connected (specification: 14×50×55). Install flange bolts with a center distance of 220×160 mm. The weight of the pump body is approximately 120 kg, and its external dimensions (length × width × height) ≈680×420×450 mm.
3. Medium and Environmental requirements
– Medium requirements: L-HM 46/68 anti-wear hydraulic oil is suitable for normal temperature, and L-HM 32 is selected for low-temperature environment; The allowable medium viscosity is 20-400 mm²/s, and the moisture content is ≤0.03%. It is strictly prohibited to use media containing solid particles (particle size > 5 μm) or corrosive media.
– Cleanliness standard: The oil cleanliness should reach ISO 4406 14/11 grade. A 5 μm fine filter should be placed in front of the oil suction port. The filter should be replaced immediately when the pressure difference of the filter is greater than 0.06 MPa.
– Environmental parameters: Operating environment temperature -20℃ to 90℃, relative humidity ≤95% (short-term condensation is allowed); With a protection grade of IP54, it is suitable for scenarios such as heavy engineering machinery, large industrial hydraulic stations, and mining equipment.Ii. Working Principle
This pump is a swashplate axial variable piston pump. The core achieves efficient output of hydraulic energy through the mechanism of “piston reciprocating volume change – swashplate Angle electrical proportional adjustment – load dynamic adaptation”. The specific process is as follows:
1. Core process of oil suction and discharge
The drive shaft rotates the cylinder block at high speed. Under the combined action of the spring force of the return disc and the hydraulic force, the plunger inside the cylinder block is always in close contact with the surface of the swash plate. When the plunger rotates with the cylinder block to the side of the swash plate that is farther from the center, the plunger extends outward, increasing the volume of the plunger chamber in the cylinder block and creating a negative pressure. Hydraulic oil is then drawn into the chamber through the suction port and the filter screen. When the plunger rotates to the side of the swash plate closer to the center, the inclined surface of the swash plate compresses the plunger to retract inward, causing a sharp reduction in volume. The oil is then discharged from the oil outlet under high pressure, completing the continuous oil suction and discharge cycle.
2. Variables and Control Mechanisms
– Electro-proportional stepless variable: By inputting a 0-5V signal through the electro-proportional controller, the proportional electromagnet is driven to adjust the tilt Angle of the swash plate (adjustable from 0 to 18°). Changes in the Angle directly modify the plunger stroke, achieving stepless adjustment of the flow rate from 0 to 106.5L /min. The response time is ≤0.3 seconds and it can precisely adapt to the dynamic changes of the load.
– Load sensitivity and safety Assurance: The load sensitive valve monitors the system load pressure in real time, automatically matches the output flow, reduces the non-working flow to below 5 L/min, and lowers the idle consumption by 45%. The built-in high-pressure relief valve automatically unloads when the system pressure exceeds 33 MPa. The oil replenishment valve prevents cavitation caused by excessive vacuum and protects the mating surface between the plunger and the cylinder block.Iii. Product Features and Advantages
– Strong heavy-duty high-pressure adaptability: With a large displacement of 71 mL/r and a working pressure of 31.5MPa, the maximum flow rate at the rated speed is 106.5 L/min. It can drive multiple actuators of 50-80 ton class equipment to work in coordination (such as excavator boom + bucket arm + rotation), without the need for multiple pumps in parallel, simplifying the system layout.
– Electro-proportional precise control: Electro-proportional + load sensitive compound control, flow regulation accuracy ±1.5%, pressure control accuracy ± 0.2MPa, can achieve fine adjustment of the speed or force of the actuator, suitable for precision heavy-duty operations (such as large hydraulic press pressing).
– High efficiency, long life and stable operation: The plunger and cylinder block are precisely ground (fit clearance ≤ 0.006mm), volumetric efficiency ≥94%; The core components are made of reinforced wear-resistant materials, capable of withstanding a short-term high-pressure impact of 35 MPa. The rated working condition fault-free operation life is ≥ 15,000 hours, which is 25% longer than that of ordinary plunger pumps.
– Integrated, reliable and easy to maintain: Integrates core components such as relief valves, oil replenishment valves, and pressure compensation valves, eliminating the need for additional valve groups. Equipped with an oil level observation window and a pressure test interface, operation and maintenance do not require disassembling the pump body. Vulnerable parts (seals, plungers, etc.) have strong versatility and relatively low annual maintenance costs.

Iv. Usage Functions and Purposes
1. Core usage functions
High-pressure variable oil supply: It provides adjustable flow rates ranging from 0 to 106.5 L/min for heavy-duty systems, meeting the all-working condition requirements of multiple actuators such as “fast action – uniform heavy load – pressure holding”, for instance, the compound actions of excavators and the multi-stage pressing of large hydraulic presses.
– Dynamic load adaptation: Real-time monitoring of system load pressure, automatic adjustment of output flow to prevent excessive flow overflow loss, adaptation to the coordinated or alternating operation of multiple actuators, and significant energy-saving effects.
– Multi-loop drive: It can be adapted to 3-4 light/heavy-duty actuators (such as crane luffing + extension + lifting) through the diverter and collector valves, achieving multi-action coordinated control, enhancing system integration, and reducing the configuration cost at the power end of the equipment.
2. Main application fields
In the field of heavy construction machinery: 50-80 ton crawler excavators (active operation circuit), 40-60 ton wheel loaders (lifting + steering + bucket circuit), 200-500 ton truck cranes (luffing + telescopic boom circuit), suitable for mining and large-scale infrastructure operations.
In the field of industrial equipment: 1000-3000 ton large hydraulic presses (main cylinder circuit), auxiliary hydraulic systems for heavy steel rolling mills (pressing device circuit), 1000-2000 ton injection molding machines (mold closing circuit), suitable for precision operations in heavy manufacturing.
– Specialized fields in mining: Medium-sized mine roadheaders (propulsion + cutting circuits), large-scale mine crushing stations (multi-hammer drive circuits), 50-100 ton cranes in ports (lifting circuits), suitable for continuous heavy loads and harsh working conditions.

V. Applicable Machines and Scenarios
1. Adapt to the core machine
– Heavy construction machinery: 50-80 ton crawler excavators, 40-60 ton wheel loaders, 200-500 ton truck cranes, large hydraulic crushing stations.
– Industrial equipment: 1000-3000 ton hydraulic presses, heavy-duty steel rolling mills, 1000-2000 ton injection molding machines, large forging machines.
– Special equipment: Medium-sized mine tunnel boring machines, 50-100 ton gantry cranes for ports, large ship hydraulic systems, garbage compression and transfer station equipment.
2. Typical application scenarios
– Excavator compound operation scenarios: As the main pump of a 60-ton crawler excavator, it distributes the flow rate through electro-proportional control (35 L/min for the boom, 30 L/min for the boom, 25 L/min for rotation, and 16.5 L/min for travel). During heavy-load excavation, the pressure remains stable at 31.5 MPa, which saves 40% energy compared to traditional multi-pump systems and is suitable for hard rock excavation operations in mines.
– Large hydraulic press forming scenario: It is used for a 2000-ton factory hydraulic press. When closing the mold quickly, it outputs a flow rate of 106.5 L/min to improve efficiency. When pressing parts, it reduces to a small flow rate of 15 L/min for pressure holding (pressure 31.5MPa), with a pressure holding accuracy of ± 0.2MPa. It is suitable for the stamping forming requirements of aerospace components and large steel structures.
– Mine tunneling scenario: It is equipped with a medium-sized mine tunneling machine, providing fuel for the propulsion cylinder (40 L/min) and the drive motor of the cutting head (66.5 L/min). It automatically adjusts the flow rate and pressure according to the hardness of the rock. The shock-resistant structure is suitable for tunneling operations, meeting the daily tunneling efficiency requirement of 15 meters.

Six. Similar models
1. Alternative models of the same series
-A4VG56EP2DM1/32L -NZF02F001DXS: Among the displacement models of the same structure, the rated displacement is 56 mL/r, the maximum flow rate is 84 L/min, and the pressure parameters are consistent. It is suitable for equipment of 40-50 tons (such as 40-ton loaders), and the cost is 22% lower than the original model.
-A4VG90EP2DM1/32L -NZF02F001DXS: Large-displacement models in the same series, with a rated displacement of 90 mL/r, a maximum flow rate of 135 L/min, and the same pressure parameters. They are suitable for equipment of 80-100 tons (such as the main circuit of an 80-ton excavator), but the cost is 30% higher than that of the original model.
2. Cross-series alternative models
-A4VG71EP2DM1/32L -NZF02F001DXS-L: Left-rotating model, with exactly the same structure and parameters, suitable for power sources with left-rotating drive shafts (such as some heavy-duty diesel engines), and the cost is the same as the original model.
-A4VG71EP2DM1/25L -NZF02F001DXS: Low-pressure compatible model, rated pressure 25 MPa, consistent displacement and flow parameters, suitable for medium and high-pressure heavy-duty systems (such as large injection molding machines), cost 18% lower than the original model.
-A4VG71DP2DM1/32L -NZF02F001DXS: Hydraulic pilot control model, no electrical proportional function, regulates flow through hydraulic signals, suitable for heavy equipment without electrical control systems (such as old cranes), cost 35% lower than the original model.

Vii. Precautions for Use
1. Medium management
At normal temperature, L-HM 46/68 anti-wear hydraulic oil is selected; at low temperature, L-HM 32 is selected. It is strictly prohibited to mix oils of different grades. Before the new pump is used for the first time, the pump body and pipelines should be flushed with clean oil in a circulating manner for ≥30 minutes to ensure that the cleanliness meets ISO 4406 14/11 grade.
– Check the pressure difference of the oil suction filter weekly (replace the filter element when it exceeds 0.06 MPa), test the moisture content of the oil monthly (≤0.03%), and take samples to test the cleanliness quarterly. When emulsification, discoloration or presence of metal impurities in the oil is detected, immediately stop the machine, change the oil and clean the pump body.
2. Installation and commissioning
When installing, ensure that the coaxiality of the drive shaft and the motor shaft is no more than 0.05mm (using an elastic coupling for positioning), and the flange bolts are evenly tightened with a torque of 800 N·m. The diameter of the oil suction pipeline should be no less than DN80, the length no more than 3m, and the number of elbows should not exceed 2 to avoid excessive oil suction resistance.
Before debugging, add hydraulic oil to the upper limit of the oil level gauge in the oil tank, and manually turn the wheel 3 to 5 times to confirm there is no jamming. Jog the motor to verify the rotation direction (right rotation), run it at low speed (1000 r/min) without load for 20 minutes, and then test the variable regulation performance through the proportional controller (no lag in flow regulation and stable pressure).
The oil suction port should be at least 500mm lower than the oil level in the oil tank, and a 0-40MPa high-pressure pressure gauge should be installed at the oil outlet. Install rain and dust covers outdoors to ensure that the protection level remains at IP54. After the hydraulic pipelines are connected, they need to be vented to prevent cavitation.
3. Operation and Maintenance
During operation, real-time monitoring of the pump body temperature (normal ≤80℃, maximum ≤90℃), outlet pressure and noise is carried out. If the temperature rises sharply by more than 15℃, the pressure fluctuates by more than 1.5MPa, or the noise abnormally increases (> 90dB), stop the machine immediately for inspection, with a focus on checking for oil contamination or wear of the plunger.
– Regular maintenance every 3,000 hours: Clean the oil suction filter screen and relief valve, and check the fit clearance between the plunger and the cylinder block (replace the matching parts when > 0.012mm). Replace the high-pressure seals and hydraulic oil, and recalibrate the relief valve pressure to 33 MPa and the zero point of the proportional controller.
– Do not run without oil (running without oil for more than 3 seconds may cause the plunger to sinter). It is strictly prohibited to operate at an excessive speed (> 2000 r/min) or under long-term overpressure (> 35 MPa). When adjusting variables, avoid sudden changes in flow rate to prevent system shock from damaging the pipelines.
4. Storage protection
When stored for a long time, use special plugs to block the oil suction port and the oil outlet, inject anti-rust oil into the pump body, and apply grease to the splines of the drive shaft. Store in a dry warehouse with a temperature ranging from 0 to 45℃ and a humidity of no more than 60%. Avoid direct sunlight and heavy object compression. Manually turn the machine once a month to prevent component adhesion.
Before putting the pump into use after being idle for more than 18 months, thoroughly clean the inner cavity of the pump and replace all high-pressure seals. After adding new oil, conduct a low-speed trial run for 2 hours to test the variable performance and pressure stability. Once no abnormalities are confirmed, connect to the system.