Construction and Function of Excavator Pump

Excavator pump is a general term. On excavators, the pump is the core hydraulic power component, equivalent to the "heart" of the excavator. Its main function is to convert the mechanical energy generated by the engine into hydraulic energy (high-pressure fluid), which then drives the various actuators (hydraulic cylinders, hydraulic motors) of the excavator to perform all actions such as digging, slewing, and traveling. Simply put: without the pump, the excavator is just a pile of immobile steel.

In reality, an excavator typically has several key pumps, which can be mainly categorized into the following types:

Main Hydraulic Pump(s): This is the most important pump, usually consisting of one or two variable displacement piston pumps (referred to as a "double pump" or "triple pump"). It primarily supplies high-pressure hydraulic oil for the excavator's main actions like the boom, arm, bucket, swing, and travel. They are typically variable displacement pumps, which can automatically change the output flow and pressure according to the control lever commands and system pressure, enabling precise, efficient, and energy-saving control.

Pilot Pump: This is a small gear pump or fixed displacement piston pump. It primarily generates lower-pressure pilot oil. This oil does not directly drive the actuators but is used to: Control the swash plate angle of the main hydraulic pump (changing displacement). Move the spools in the control levers, enabling pilot hydraulic control (resulting in lighter and more precise operation). Provide control fluid for some control valves. Although the pressure is lower, stability is crucial, making it key for achieving precise control.

Other Auxiliary Pumps: On some excavator models, there may also be: Water pump: For the cooling system, circulating coolant. Fuel transfer pump: Transfers fuel from the tank to the engine. Lubrication pump: Provides centralized lubrication for large or specific mechanisms.

Among excavator hydraulic pumps, the most common type is the axial piston variable displacement pump, whose core technology is the "swash plate" or "bent axis" design. By changing the angle of the swash plate, the stroke of the pistons is altered, thereby varying the displacement.

Common problems with excavator pumps include:

Loss of Efficiency/Sluggish Operation: Internal wear (e.g., pistons, valve plates) leading to increased internal leakage, resulting in insufficient pressure and flow.

Abnormal Noise: Insufficient suction (clogged filter), air ingress, or damaged internal components.

Overheating: Severe internal leakage or fluid contamination.

Failure to Variable: Abnormal pilot pressure or stuck variable mechanism.

Key maintenance points:

Maintain Hydraulic Fluid Cleanliness: Regularly changing the hydraulic fluid and filters (return filter, pilot filter, suction filter) is the most important measure to protect the pump. The vast majority of pump failures originate from fluid contamination.

Use the correct grade of hydraulic oil.

Avoid prolonged overload operation.

Conduct regular inspections: Detect abnormal noise or temperature rise early.

Excavator Pump specifically refers to the core pump assembly that provides power for the excavator's hydraulic system, mainly including: Main Pump(s): Provides power, does the "heavy lifting". Pilot Pump: Provides control, does the "precision work".

Together, they convert the diesel engine's power into hydraulic energy, directing the excavator to perform various complex actions. Due to their critical importance, they are also among the most closely watched components in excavator maintenance and repair.

You can think of it this way: The engine is the excavator's "stomach" (digesting fuel to produce energy), while the hydraulic pump is the "heart" (pressurizing and distributing that energy to all parts of the body)

Elephant Fluid Power company boasts over a decade of manufacturing experience and is now the largest producer of hydraulic products in Northern China. We operate three specialized production lines equipped with advanced German manufacturing equipment. If you are interested in our products, please feel free to contact us for purchasing inquiries.

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