Noise Analysis of Hydraulic Piston Pump

Mechanical noise

The main parts of the mechanical noise from the pump are (1) The joint between the pump main shaft and the engine is damaged. ⑵ pump bearings.

If the main shaft of the pump is not concentric with the output shaft of the engine or is dead, the elastic coupling is damaged and the bolts on the coupling block are loose, all of which will generate noise.

If it is the sound of bearing damage, there will be a continuous beeping sound. As the speed of the pump increases, the noise also increases. If the bearing is damaged, the pump will vibrate.

The mechanical noise of the pump can be heard by the human ear. The best way is to listen to various parts of the pump with an industrial stethoscope or a through screwdriver when the pump is running at low speed.

sudden noise

Once the pump has a sudden noise, the pump must be stopped immediately. In this case, the parts of the pump have been damaged.

The piston of the inclined axis pump is broken or the piston shoe of the swash plate pump falls off, and the return plate is broken. The noise that occurs for this phenomenon is a continuous loud thumping noise that accompanies each revolution of the pump. It's like someone set off firecrackers inside the pump body. At the same time, there is a pulsation phenomenon in the pressure hose of the P port of the pump.

Once there is a sudden noise, the most important thing is not to increase the pressure of the hydraulic system, because the broken metal slag of the parts in the pump casing will enter the system with the pressure oil. The sudden noise of the pump is terrible. It is not just the damage of the pump. Once the broken metal slag enters the hydraulic system, it cannot be removed, and it will cause lifelong damage to the hydraulic system.

Pump noise after changing hydraulic oil

This kind of noise is that the air in the newly replaced oil has not fully escaped. When the pump swallows air bubbles, under the action of high pressure at the outlet of the pump, these air bubbles will suddenly be crushed and burst, causing a cascade sound. The reason is that the quality of the newly replaced hydraulic oil is poor, the storage time is long, the antifoaming additive in the oil is oxidized or the adverse reactions caused by the incompatibility of various chemical additives in the oil cannot eliminate the air in the oil. effect.

Any brand of mineral hydraulic fluid contains about 10% air. The air exists in the oil hydraulics in two ways, one is in the form of bubbles in the oil, and the other is dissolved in the liquid in the form of molecules, which cannot be seen. The increase in volume of the liquid is not noticeable.