A Comprehensive Analysis of the Working Principle and Maintenance of the Crane Hydraulic System

 

I. Working Principle of the Crane Hydraulic System

The core principle of the crane hydraulic system is based on Pascal's Law, which states that the pressure in a confined liquid can be uniformly transmitted to all points of the liquid without changing the direction. When the hydraulic pump exerts pressure on the hydraulic oil, this pressure is transmitted through the pipeline to the hydraulic cylinder or hydraulic motor, converting hydraulic pressure into mechanical energy to drive the crane to perform actions such as lifting, extension, and rotation. For example, when the boom is lifted, the high - pressure oil output by the hydraulic pump pushes the piston of the hydraulic cylinder to move. The pressure amplification effect (through pistons of different areas) enables the system to easily handle heavy loads.

 

II. Key Steps in Hydraulic System Maintenance

1. System Flushing

New hydraulic systems or those after major overhauls need to be thoroughly flushed to remove residual metal chips, contaminants, etc. When flushing, special cleaning agents should be used, and the oil circulation should be ensured for more than 2 hours to avoid early failures caused by impurities.

 

2. Regular Maintenance Plan

- Filter Element Replacement: Check and replace the oil filter every 500 hours or three months to prevent clogged filters from causing a drop in oil pressure.

- Oil Detection: Regularly test the acid value, water content, and pollution level of the hydraulic oil, and promptly replace the deteriorated oil.

- Sealing Inspection: Repair leaks in pipelines, joints, etc., ensure that the tank vent cap and return oil pipeline are well - sealed to prevent external particles from entering.

- Pump and Valve Maintenance: Clean the inlet filter of the oil pump, check the wear of the valve core, and reduce the risk of internal leakage.

 

III. Diagnosis and Troubleshooting of Common Faults

1. Slow or Weak Boom Lifting

Cause: Insufficient working oil pressure, which is often caused by clogged oil circuits (such as clogged filter elements) or external leakage (such as damaged sealing rings).

Treatment: Check the condition of the filter element, clean the clogged pipeline; replace the failed sealing parts; if the internal leakage of the hydraulic cylinder is serious, replace the piston sealing assembly.

 

2. Slow Action of the Swing Mechanism

Cause: Insufficient oil supply to the hydraulic motor or internal leakage, which may be caused by stuck spool valves due to oil contamination.

Treatment: Clean the control valve of the swing motor, check the cleanliness of the oil; test the volumetric efficiency of the motor, and replace the worn parts if necessary.

 

3. System Overheating

Cause: Improper oil viscosity, clogged cooler, or frequent opening of the relief valve.

Treatment: Adjust the oil viscosity to the recommended value, clean the radiator fins of the cooler, and calibrate the set pressure of the relief valve.

 

IV. Impact of Maintenance on System Lifespan

Standardized maintenance can significantly extend the lifespan of the hydraulic system. For example, regularly replacing the filter element can reduce the wear of pumps and valves and avoid sudden failures caused by particle pollution; timely repair of leaks can maintain stable system pressure and reduce energy consumption. According to statistics, the failure rate of the hydraulic system of cranes that strictly follow the maintenance plan can be reduced by more than 60%.

 

V. Conclusion

The stable operation of the crane hydraulic system depends on the scientific application of Pascal's Law and meticulous management. Through measures such as regular flushing, filter element replacement, and leakage inspection, faults can be effectively prevented and the operation efficiency can be improved. At the same time, mastering the diagnostic methods for common problems can quickly restore the equipment performance and ensure the safety and economy of lifting operations.