Causes of Noise Generation in Excavator Hydraulic Systems

Operators with years of experience operating excavators have likely encountered situations where the hydraulic system produces abnormal sounds. What are the reasons behind the noise generated in the hydraulic system of excavators? Today, let's analyze the causes of noise generation in excavator hydraulic systems and how to address them.

1. Air Intrusion

When air intrudes into the hydraulic system of excavators, it experiences compression as it moves from low-pressure areas to high-pressure areas. This sudden change in volume, known as the "explosion" phenomenon, occurs when air bubbles suddenly change volume, resulting in noise.

The usual solution is to install exhaust devices on hydraulic cylinders for air release. Another common method is to operate the components rapidly through the full stroke several times after driving to release air.

2. Poor Quality Hydraulic Pump or Motor

Poor-quality hydraulic pumps may not meet technical requirements in terms of precision, leading to fluctuations in pressure and flow, inadequate elimination of trapped oil, poor sealing, and low-quality bearings, all of which are major causes of noise. Additionally, wear and tear on hydraulic pump components during use, resulting in excessive clearances and inadequate flow, can also cause noise.

The solution is to choose high-quality hydraulic pumps or motors and perform regular maintenance and repairs. For example, if the gear teeth have low precision, they should be re-profiled to meet contact surface requirements. If there is trapped oil in vane pumps, the triangular grooves of the distributor plate should be corrected to eliminate trapped oil. If there is excessive axial clearance in the hydraulic pump resulting in insufficient oil delivery, it should be repaired to maintain clearance within permissible limits. If the hydraulic pump selection is incorrect, it should be replaced immediately.

3. Improper Adjustment of Directional Valves

Inadequate adjustment of directional valves, causing the valve spool to move too quickly, results in directional impact, leading to noise and vibration.

During operation, the valve spool of the hydraulic valve is supported on a spring. When its frequency is close to the pulsation frequency of the hydraulic pump or other vibration sources, it may cause vibration and noise.

The solution is to adjust the throttle components in the control oil circuit of the directional valve to ensure smooth and impact-free directional changes. Changing the inherent frequency of the pipeline system, adjusting the position of the control valve, or adding accumulators appropriately can prevent vibration and reduce noise.

4. Unstable Relief Valve

For example, improper mating of the spool and valve hole, blockage of debris at the contact between the conical valve and valve seat, blockage of the damping hole, or misalignment or failure of the spring, causing the valve spool to jam or move poorly in the valve hole, resulting in pressure fluctuations and noise in the system.

The solution is to pay attention to cleaning and unblocking the damping holes and to inspect relief valves. If damage is found, repair or replacement should be performed promptly.

5. Mechanical Vibration

Long and slender oil pipes with many elbows that are not properly secured can cause pipe vibration when the oil flow rate is high. Unbalanced rotating parts of electric motors and hydraulic pumps, poor alignment during installation, or loose coupling joints can all generate vibration and noise.

The solution is to suggest separating longer oil pipes and isolating them from the machine wall with appropriate support pipe clamps. Adjust the installation accuracy of electric motors and hydraulic pumps and reinstall the coupling joints to ensure coaxiality is less than 0.1mm.

In conclusion, addressing these issues related to noise generation in excavator hydraulic systems not only improves operational efficiency but also enhances the safety and comfort of operators, underscoring the importance of regular maintenance and proactive measures in ensuring optimal performance and longevity of hydraulic equipment.

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