Excavator Hydraulic Piston Pump A8V055 A8V080 A8V0107 A8V0120 A8V0140 A8V0200 Series A8VO80LA1KH1/61R1-NZG05F004

I. Core Technical Parameters
1. Basic performance parameters- Pump body type: Special closed-loop swashplate axial piston variable pump for excavators, integrated constant power control and pressure cut-off device, supports unidirectional rotation, suitable for the main hydraulic system of medium and large excavators

– Displacement and pressure parameters: Rated displacement 80 cc/rev (” 80 “in the model indicates the core displacement), variable range 0-80 cc/rev continuously adjustable; The rated working pressure is 350 bar, the maximum allowable pressure for walking/rotating conditions is 400 bar (short-term ≤10 seconds), the pilot control pressure is 10-14 bar, and the pressure cut-off set value is 380 bar±5%

– Rotational speed and flow parameters: Rated rotational speed 2000 rpm (compatible with the commonly used rotational speed of excavator engines), maximum rotational speed 2400 rpm (short-term ≤5 minutes), minimum stable rotational speed 600 rpm; The maximum output flow at the rated speed is 160 L/min (80 cc/rev×2000 rpm÷1000), the flow pulsation rate is ≤3%, and the constant power regulation flow response time is ≤150 ms

– Efficiency parameters: Rated working condition volumetric efficiency ≥94%, total efficiency ≥87%; The power fluctuation in the constant power control range is no more than 5%, and the system pressure loss at the rated flow is no more than 4 bar

2. Structure and connection parameters

– Structural type: High-strength ductile iron pump body (tensile strength ≥400 MPa), surface cathodic electrophoresis anti-rust treatment; The cylinder body is symmetrically distributed with 9 plungers, featuring nitrided alloy steel plungers (hardness HRC62-65), high-frequency quenched swash plates (surface hardness HV900-1000), and static pressure balanced distribution plates. Double-row angular contact ball bearing support, skeleton mechanical seal + polytetrafluoroethylene lip seal combination, static leakage ≤1.0 mL/min; Integrated anti-cavitation oil suction valve and high-pressure buffer valve

– Installation and connection specifications: Flange installation (compatible with the standard of excavator engine flywheel housing, “61R1” corresponds to installation positioning); Oil port threads: Suction port G1½, high-pressure outlet port G1¼, pilot port G1/4; The output shaft is connected by involute splines (specification 8×32, special spline standard for excavators). The overall weight is approximately 32 kg, and the external dimensions (length × width × height) are approximately 380×260×220 mm, which is suitable for the compact layout of the excavator engine compartment

– Protection grade: IP67, suitable for dusty, rainy and high-vibration (vibration acceleration ≤ 20g) conditions on construction sites, supports horizontal axial installation, and allows an installation inclination deviation of ±5°

3. Medium and Environmental requirements

– Medium requirements: Suitable for excavator-specific L-HM 46 anti-wear hydraulic oil. In low-temperature areas, L-HM 32 low-pour anti-wear hydraulic oil can be selected. The allowable medium viscosity range is 10-350 mm²/s, the optimal working viscosity is 15-45 mm²/s, the moisture content is ≤0.03%, and the solid particle contamination degree should reach ISO 4406 15/12 grade. In harsh working conditions such as mines, it should be raised to 14/11 grade

– Environmental parameters: Working environment temperature -30℃ to 90℃ (suitable for high and low temperature construction sites), relative humidity ≤98%; The optimal working temperature of the oil is 40-60℃, and the short-term allowable temperature is ≤95℃ (≤30 minutes). Adapt to an altitude of no more than 4,000 meters. In high-altitude areas, the pressure of the breathing valve needs to be adjusted

– Filtration requirements: A coarse filter screen of ≥100 mesh (with a differential pressure alarm device) must be installed on the oil suction side. A high-pressure filter with an accuracy of ≤10 μm should be added to the oil outlet. A magnetic filter (with a filtration accuracy of ≤25 μm) should be equipped on the oil return side. The system needs to integrate an online monitoring interface for oil contamination

Ii. Working Principle

This pump is a special swash plate axial piston variable pump for excavators. Its core achieves efficient conversion between mechanical energy and hydraulic energy through “piston reciprocating volume change + constant power variable regulation”. Combined with multiple protection mechanisms, it is suitable for the compound action conditions of excavators. The specific operation mechanism is as follows:

1. Core mechanism of power transformation

The excavator engine drives the pump shaft to rotate through a coupling, which in turn rotates the cylinder block synchronously. Under the combined action of the thrust from the inclined surface of the swash plate and the return spring, the plunger moves back and forth along the plunger holes of the cylinder block in a straight line. When the plunger rotates with the cylinder body to the oil suction zone, the plunger extends outward, increasing the volume of the plunger hole and creating a vacuum environment. The hydraulic oil is then sucked in through the oil suction port, the coarse filter screen and the oil suction chamber of the distribution plate. When the plunger rotates to the oil pressure zone, the swash plate compresses the plunger to retract inward, reducing the volume of the plunger holes. The oil is compressed to generate high pressure, which is then guided through the oil pressure chamber of the distribution plate and the high-pressure filter to the actuator components of the excavator (boom cylinder, bucket rod cylinder, rotary motor, walking motor, etc.) to provide working power. The output flow rate is positively correlated with the inclination Angle of the swash plate. The greater the inclination Angle, the longer the plunger stroke, and the greater the output flow rate.

2. Variable regulation and protection mechanism

It adopts a dual-variable control mechanism of “constant power + pressure cut-off” : The constant power control module monitors the output pressure and flow rate of the pump in real time. Through pressure feedback acting on the variable piston, it changes the inclination Angle of the swash plate, keeping the pump output power always stable within the rated power range of the engine (power fluctuation ≤5%), avoiding engine overload. When the system pressure rises to the pressure cut-off set value of 380 bar, the variable mechanism quickly reduces the swash plate Angle to the minimum, and at the same time, the high-pressure relief valve opens to unload, preventing damage to the pump body and pipelines. The integrated anti-cavitation oil suction valve automatically opens to replenish oil when the suction pressure is too low, preventing cavitation damage. The high-pressure buffer valve can absorb the pressure shock during heavy excavation (with a maximum shock pressure attenuation of 35%). The distribution plate adopts a self-lubricating coating, which can automatically compensate for the wear gap and ensure the long-term stability of volumetric efficiency.

Iii. Product Features and Advantages

– Precise adaptation to excavator operating conditions: Constant power control perfectly matches the excavator’s operation characteristics of “high speed under light load and low speed under heavy load”. The flow distribution accuracy during compound actions is ±3%, which saves 25%-30% energy compared to ordinary variable pumps. The 150ms rapid flow response is adapted to the compound action switching of excavation, rotation and walking, with no lag in operation and a 15% increase in work efficiency

– Strong resistance to harsh environments: With an IP67 protection rating, it can withstand rain, dust, and high-vibration environments on construction sites. The anti-rust life of the cathodic electrophoresis pump body is 50% longer than that of ordinary phosphating treatment. The nitrided plunger and quenched swash plate friction pair have excellent wear resistance. Under rated working conditions, the fault-free operating life is ≥ 12,000 hours, and under harsh working conditions in mines, the service life is ≥ 8,000 hours

– High pressure resistance and safety reliability: A rated pressure of 350 bar is suitable for the heavy-load requirements of excavators, and a short-term pressure resistance capacity of 400 bar can handle impact loads such as walking, climbing slopes, and hard rock excavation. Dual protection of pressure cut-off and relief valve, unloading within 0.2 seconds when overloaded, to avoid the risk of system pipe burst. The anti-cavitation design ensures that the suction vacuum degree is ≤0.02 MPa, making it suitable for low oil level conditions in the oil tank

– Easy maintenance and wide adaptability: The modular valve group design ensures that the core component replacement time is no more than 1 hour, and basic maintenance can be completed on-site at the construction site. By replacing the flange adapter, it can be adapted to excavators of different tonnages ranging from 15 to 25 tons. It supports integrated drive with gear pumps and steering pumps, simplifying the layout of the hydraulic system

Iv. Usage Functions and Purposes

1. Core usage functions

Constant power variable fuel supply: Automatically adjust the displacement according to the engine power, achieving stepless flow variation from 0 to 160 L/min, meeting the flow requirements of different actions such as the lifting of the excavator boom, the digging of the bucket arm, rotation, and walking, and avoiding engine stalling

– Compound action flow distribution: When multiple actuating elements operate simultaneously, the flow is automatically allocated based on the load priority. For instance, when performing a compound action of excavation and rotation, the flow in the excavation circuit is prioritized to ensure the continuity of the operation

– Heavy-load safety protection: In heavy-load conditions such as hard rock excavation and walking and climbing slopes, when the pressure exceeds 380 bar, it can be quickly unloaded. At the same time, the buffer valve absorbs the impact to protect the pump body, pipelines and actuating elements. When the engine speed drops, the displacement is automatically reduced to maintain power balance

– Low-loss and energy-saving operation: When moving rapidly under light load, the displacement automatically increases the speed; when operating under heavy load, the displacement decreases to ensure pressure. Compared with the fixed displacement pump system, the fuel consumption is reduced by more than 25%, and the temperature rise of the hydraulic oil is also reduced at the same time

2. Main uses

As the main hydraulic power source for 15-25 ton excavators, it connects the engine with the hydraulic execution system, achieving efficient conversion of mechanical energy from the engine to hydraulic energy, and providing stable power for core operation actions such as excavation, rotation, lifting, and walking. It is the “power core” of the hydraulic system of excavators and can also be adapted to the main hydraulic systems of excavators and loaders of the same tonnage, small crawler cranes and other construction machinery.

V. Applicable Machines and Scenarios

1. Adapt to the core machine

– Excavators: Main hydraulic systems for 15-ton, 20-ton, and 25-ton crawler excavators, driving boom, bucket, bucket, rotary motor, walking motor and other actuating components

– Other construction machinery: 18-22 ton excavator loader boom system, 20-25 ton small crawler crane luffing and slewing system, 15-20 ton hydraulic breaker power source

– Special engineering equipment: Small tunnel boring machine advancement system for mines, hydraulic grab machine drive system for construction sites

2. Typical application scenarios

– Earthwork excavation scenario: Compatible with 20-ton crawler excavators. When excavating ordinary soil, the pump displacement automatically stabilizes at 60-70 cc/rev (120-140 L/min), and the excavation speed is 0.9m /s. When the load on the hard soil layer increases, the displacement rises to 80 cc/rev (160 L/min) within 150 ms, the pressure increases to 320 bar, and the constant power control keeps the engine speed stable at 1800 rpm without any stalling

In the scenario of compound action operation: When the excavator simultaneously performs the compound actions of boom lifting, bucket retraction and rotation, the constant power system automatically allocates the flow rate. The boom cylinder reaches 60 L/min, the bucket cylinder reaches 40 L/min, and the rotation motor reaches 50 L/min. The actions are coordinated without any lag, and the efficiency is increased by 30% compared with single-action operation

– Heavy-duty mining scenarios: Compatible with 25-ton mining-specific excavators, IP67 protection resistant to mine dust and water spray environments, magnetic oil return filter adsorbs metal grinding debris, and the oil cleanliness is maintained at 15/12 grade. During hard rock excavation, the pressure frequently reaches 350-380 bar. The pressure cut-off device provides stable protection. After continuous operation for 8 hours, the pump body temperature is ≤85℃, and it can run without failure for 10,000 hours

– Walking and climbing scene: When the excavator is climbing a 30° steep slope, the load on the walking motor increases, and the pump pressure rises to 380 bar. The pressure cut-off device quickly reduces the displacement from 80 cc/rev to 40 cc/rev, maintaining the climbing power while avoiding engine overload. The climbing speed is stabilized at 2.5 km/h

Six. Similar models

1. Different models of the same series displacement

-A8VO63LA1KH1/61R1-NZG05F004: Rated displacement 63 cc/rev, rated speed 2000 rpm flow rate 126 L/min, rated pressure 350 bar, suitable for 12-15 ton small excavators, weight approximately 28 kg, volume reduced by 15% compared to the original model

-A8VO107LA1KH1/61R1-NZG05F004: Rated displacement 107 cc/rev, rated speed 2000 rpm, flow rate 214 L/min, maximum pressure 400 bar, suitable for medium-sized excavators ranging from 25 to 30 tons. The power is 34% higher than the original model, and the weight is approximately 38 kg

-A8VO55LA1KH1/61R1-NZG05F004: Rated displacement 55 cc/rev, rated speed 2000 rpm flow rate 110 L/min, rated pressure 350 bar, suitable for 10-12 ton ultra-small excavators, weighing only 22 kg, with a more compact structure

2. Models with the same displacement but different functions

-A8VO80LA1DR1/61R1 -NZG05F004: Constant pressure control type. Once the system pressure reaches the set value, the displacement will automatically decrease. It is compatible with the auxiliary hydraulic system of excavators (such as breakers), with a pressure control accuracy of ±1 bar. The cost is 18% lower than that of the original model

-A8VO80LA1EP1/61R1-NZG05F004: Electric proportional control type, supports remote control of displacement by 4-20mA electrical signal, compatible with intelligent electric control excavators, can achieve one-click switching of operation modes, flow regulation accuracy ±0.5%, cost 40% higher than the original model

-A8VO80LA1LR1/61R1-NZG05F004: Load-sensitive type, it can adjust the flow rate in real time according to the load requirements of the actuator, and is suitable for equipment such as backhoe loaders where multiple actuators frequently switch. The energy-saving effect is 10% higher than that of the original model

Vii. Precautions for Use

Installation and commissioning

When installing, it is essential to ensure that the coaxiality error between the pump shaft and the engine crankshaft is ≤ 0.08mm. Use a special elastic coupling for excavators for connection. Rigid connection or radial force (≥ 150N) acting on the pump shaft is strictly prohibited. The pump body fixing bolts should be 10.9 grade high-strength bolts with a pre-tightening torque of ≥120 N·m to prevent loosening caused by site vibration

The oil suction pipeline should comply with the principle of “short, straight, thick + anti-pollution” : length ≤1.5 meters, inner diameter ≥ 32mm, and the distance from the oil suction port to the bottom of the oil tank ≥ 150mm. The oil suction filter screen needs to be cleaned regularly (every 50 hours). The pipeline connection adopts high-pressure resistant sealing rings to ensure no air leakage. A vacuum gauge (vacuum degree ≤0.02 MPa) is installed on the oil suction side.

Before the first start-up, fill the pump cavity with excavator-specific hydraulic oil (about 500 mL), and manually turn the machine 5-6 times to confirm that the plunger extends and retracts smoothly. When starting, first idle at 800 rpm for 10 minutes, then increase to the rated speed, gradually load to the rated pressure, and at the same time calibrate the constant power control curve and the pressure cut-off value (set at 380 bar). After the debugging is completed, lock the adjusting mechanism to prevent accidental contact

A heat dissipation space of no less than 200mm should be reserved around the pump body, and a forced ventilation device should be installed in the engine compartment. Before starting in winter in the north, the hydraulic oil should be preheated to above 10℃ to avoid wear during low-temperature starting. High-altitude areas (> 3,000 meters) require the replacement of high-altitude dedicated breathing valves

2. Operation and Maintenance

During operation, key parameters need to be monitored in real time: pump body temperature (normal ≤85℃, maximum ≤95℃), outlet pressure (fluctuation ≤5 bar), and operating noise (≤85 dB). When working on the construction site, a check should be conducted every two hours. If there is a sudden temperature rise exceeding 15℃, abnormal pressure or abnormal noise, the machine should be stopped immediately for inspection. The focus should be on checking the cleanliness of the oil (once every 200 hours), jamming of the variable mechanism or leakage of the seal

– Regular maintenance cycle: Under normal working conditions on the construction site, replace the hydraulic oil and the three-stage filter every 1,000 hours. Replace every 600 hours under harsh working conditions in mines. Disassemble and inspect every 8,000 hours. Replace the plunger when the diameter wear is ≥ 0.05mm and the swash plate scratch is ≥ 0.03mm. At the same time, replace the seal and the return spring. Calibrate the constant power control module and the pressure shut-off valve every 1500 hours

– Do not run without oil (running without oil for more than 3 seconds may cause column serra injury). Do not operate for a long time (> 10 seconds) under the maximum pressure of 400 bar. When excavating hard rock, avoid pushing the operation handle forcefully to reduce pressure impact. Before shutting down, it is necessary to idle and run without load for 5 minutes. After the oil temperature is ≤60℃, the power should be cut off

3. Storage and Protection

When stored for a long time (more than one month), all items should be sealed with special plugs