Excavator main pump

The excavator main pump is the core power source of the hydraulic system, and its performance directly affects the operational efficiency and reliability of the equipment.

First, structure and working principle

Excavator main pump is mostly swash plate axial piston pump, through the drive shaft to drive the cylinder rotation, the plunger in the swash plate tilt under the action of reciprocating motion, to realize the oil suction and discharge. Take Kawasaki K3V series as an example:

Dual-pump tandem design: the front pump and rear pump share the same suction port and are connected by spline joints to achieve synchronized oil supply.

Variable control: Displacement is changed by adjusting the swashplate inclination, adapting to load changes and reducing energy consumption.

Key components:

1、Rotary mechanism: the drive shaft, cylinder body, plunger and so on form the rotary motion unit.

2、Swash plate mechanism: swash plate, servo cylinder, etc. to realize the displacement adjustment.

3, valve cover mechanism: valve block, valve plate to control the flow of oil.

Second, common types and features

1、Double pump linkage main pump

Characteristics: to realize forward, backward and other multi-action synergies, to adapt to complex working conditions.

Disadvantage: high risk of internal leakage, need to regularly check the seals.

2、Triple linkage main pump

Characteristics: support a variety of action status, convenient maintenance.

Disadvantage: poor flow balance, need to optimize the system design.

3、Single pump independent main pump

Features: simple structure, low maintenance costs, suitable for small and medium-sized excavators.

Disadvantages: unable to support multiple actions at the same time, efficiency is limited.

4、K3V/K5V main pump

Characteristics: low oil temperature, no fluid addition, low noise, widely used in modern excavators.

Advantage: significant energy saving effect, long life.

Third, maintenance and troubleshooting about hydraulic main pump

1, Daily Maintenance

Fluid management: Change hydraulic oil and filter element every 2000 hours to ensure NAS8 level cleanliness.

Seal check: check the seal ring every 500 hours to prevent leakage.

No-load operation: avoid prolonged no-load operation to prevent the pump from overheating.

2、Common faults and treatment

Pump output flow is low, pressure can not be established: check the flow distribution disk wear, plunger vice clearance.

Vibration, noise: check the bearing, gear and other rotating parts wear.

Engine overload: check whether the system pressure is too high, adjust the flow regulator.

Main hydraulic pump diagram

Excavator hydraulic pump types