The main Hydraulic Pump,commonly known as the large pump,is the power heart of the entire hydraulic system of excavators.The vast majority of them are variable displacement piston pumps,and some small excavators use gear pumps.The engine power is transmitted to the hydraulic pump,which converts mechanical energy into high-pressure hydraulic oil,providing high-pressure oil for the main control valve,various oil cylinders,walking motor,rotary motor,and Fan Motor.All the power for the entire machine comes from the main hydraulic pump.

　　Mainstream medium and large excavators often use dual pump merging,consisting of a combination of two plunger pumps and a regulator(elevator).The core components include:pump housing,cylinder body,plunger slide shoe,distribution plate,swash plate,servo piston,and regulator.The regulator receives pilot pressure and power control signals,and changes the angle of the inclined plate in real time to adjust the output displacement of the pump.Reduce displacement and engine power consumption under light load conditions;When mining heavy loads,increase the displacement and output a large flow rate.At the same time,it has constant power control to prevent the pump from absorbing more power than the engine output,and to avoid stalling the vehicle.

　　The internal plunger,slide shoe,and friction pair of the hydraulic pump rely entirely on hydraulic oil lubrication and cooling.Metal impurities and moisture in hydraulic oil can directly strain the friction pair,causing early wear.Mining heavy load conditions,long-term high flow and high pressure output of pumps,high impact load,and faster wear rate;The workload of earthwork leveling operations is relatively relaxed.

　　Hydraulic pump failure does not trigger a separate alarm.Common manifestations include slow and sluggish operation of the entire machine,stalling and losing speed,uncoordinated operation,abnormal heating of the pump body,loud noise,and excessive return oil flow from the drain port.Many fault phenomena are similar to those of the main valve and pilot system,and it is necessary to measure the pressure and flow rate with a pressure gauge to confirm that the pump body is damaged.The main hydraulic pump is a high-value precision hydraulic component that requires professional hydraulic test bench maintenance and calibration after wear and tear.Pay attention to the maintenance of hydraulic oil and filter elements,which can effectively extend the service life of hydraulic pumps and avoid complete machine paralysis and shutdown.