A Detailed Explanation of the Composition and Working Principle of the Excavator Hydraulic System: Structural Analysis and Function Description

 

As the core power transmission unit of the equipment, the design of the excavator hydraulic system directly affects the operation efficiency and mechanical stability. This article will conduct an analysis from three aspects: system composition, working principle, and functional characteristics, helping readers comprehensively understand the operating mechanism of the hydraulic system.

 

I. Core Components of the Hydraulic System

1. Power Component: Hydraulic Pump

The hydraulic pump is the power source of the system, responsible for converting the mechanical energy of the engine into hydraulic energy. Common pump types include gear pumps, vane pumps, and piston pumps. Among them, piston pumps are widely used in large - scale excavators due to their high - pressure and high - efficiency characteristics.

 

2. Actuating Components: Hydraulic Cylinders and Hydraulic Motors

Hydraulic cylinders achieve linear motion (such as the extension and retraction of the boom), and hydraulic motors are responsible for rotational actions (such as the slewing platform). Both are driven by pressurized oil, converting hydraulic energy into mechanical energy to complete core actions such as excavation and lifting.

 

3. Control Component: Multi - Way Valve Group

As the control center of the system, the multi - way valve precisely coordinates each actuating component by regulating the flow direction, pressure, and flow rate of the oil. It mainly includes directional control valves (to control the direction of action), pressure control valves (to limit the system pressure), and flow control valves (to adjust the speed of action).

 

4. Auxiliary Components: Ensure Stable System Operation

- Hydraulic Oil Tank: Stores hydraulic oil and has the functions of heat dissipation and sedimentation of impurities.

- Filter: Filters impurities in the oil to protect precision components.

- Radiator: Maintains the oil temperature in the optimal working range of 50 - 80°C.

- Pipelines and Seals: Ensure the leak - free transmission of high - pressure oil.

 

5. Working Medium: Hydraulic Oil

Select hydraulic oil with anti - wear, anti - oxidation, and stable viscosity - temperature properties. It is not only a carrier for energy transfer but also plays the roles of lubrication and cooling.

 

II. Working Principle of the Hydraulic System

The hydraulic system follows Pascal's law and transmits pressure through a closed oil circuit:

1. The engine drives the hydraulic pump to generate high - pressure oil.

2. The multi - way valve group distributes the oil to the specified actuating components according to the operation instructions.

3. The hydraulic oil pushes the piston of the hydraulic cylinder or the rotor of the motor to produce mechanical motion.

4. The return oil returns to the tank after filtering and cooling, forming a complete cycle.

 

This process can achieve a power amplification effect. For example, a small - flow control valve can be used to manipulate a large - tonnage hydraulic cylinder, reflecting the unique advantage of the hydraulic system of "using a small force to achieve a large effect".

 

III. System Functional Characteristics and Advantages

1. Efficient Power Transmission

The transmission efficiency of the hydraulic system can reach 80% - 90%, far exceeding that of mechanical transmission methods, especially suitable for heavy - load operation scenarios.

 

2. Precise Motion Control

Through the combination of proportional valves and electronic control technology, modern hydraulic systems have achieved millimeter - level motion accuracy to meet the needs of complex working conditions.

 

3. Compact Structural Design

Hydraulic components have a high power density. Compared with mechanical transmission, they save more than 40% of space, which is beneficial for the optimization of equipment layout.

 

4. Multiple Safety Protections

- Pressure limiting valves prevent system overloading.

- Temperature sensors monitor the state of the oil.

- Emergency manual pumps ensure basic operations during power outages.

 

IV. Maintenance Points and Common Fault Prevention

1. Regularly Replace the Hydraulic Oil (It is recommended to replace it every 2000 hours).

2. Maintain the Filter Element on Schedule (Check it every 500 hours).

3. Monitor the Condition of Seals (Prevent efficiency decline caused by leakage).

4. Response to Typical Faults

- Slow Action: Check for pump wear or spool jamming.