Created on:2021-08-25 13:43

Fault diagnosis and maintenance of marine hydraulic equipment_ Noise and vibration fault of hydraulic system of ship crane

Fault diagnosis and maintenance of marine hydraulic equipment_ Noise and vibration fault of hydraulic system of ship crane

The causes of noise and vibration faults are very complex. Not only the mechanical equipment and electrical appliances of the system can cause noise and vibration, but also almost every link of the hydraulic system. Air mixing in the system, mechanical vibration, failure of control valve and other components, pressure and flow pulsation in the system, as well as the resulting resonance are all the causes of noise and vibration. It is difficult to analyze and deal with this kind of fault. We must preliminarily judge which type of cause is caused according to the fault characteristics, and then find out the fault cause and eliminate it through oil pouring, inquiry, inspection, and even disassembly inspection.

The hydraulic system of a certain wheel of cargo crane screamed during operation. Through careful inspection, it is found that this sound occurs when the system pressure is 4.5 ~ 6.5MPa, and increases with the increase of pressure. When the pressure rises to 6.5MPa, the system produces continuous howling. In addition, it was found that the whistling occurred on the overflow valve of the outlet pipeline of the hydraulic pump, but there was no such sound on the pump and other valves. Therefore, it is considered that the howling is related to the overflow valve. After disassembling the valve, it is found that the damping hole on the main valve core is too large. After replacing the valve core, the whistling sound is eliminated.

The damping hole on the main valve core is too large. When the pressure oil under the main valve core passes through the damping hole on the valve core and acts on the cone valve on the pilot valve, the pressure pulsation of the pressure oil resonates with the spring on the cone valve, causing the vibration of the cone valve to produce noise. After the damping hole becomes smaller, the pressure oil acts on the cone valve through the damping hole. Since the pressure of the pressure oil reaches equilibrium after passing through the damping hole, it will no longer resonate with the spring on the cone valve, the cone valve will no longer vibrate, and the roar will be eliminated immediately.

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