Sources of Noise in Hydraulic Systems
01.Noise of pressure relief valve
Relief valve is easy to produce high-frequency noise, mainly due to the unstable performance of the pilot valve, that is, for the pilot valve front cavity pressure high-frequency oscillation caused by air vibration and noise. Its main reasons are:
①Oil mixed into the air, in the pilot valve front cavity to form air pockets phenomenon and trigger high-frequency noise. At this time, the air should be exhausted in time and prevent the re-entry of outside air.
②Needle valve in the course of use due to frequent opening and excessive wear, so that the needle valve cone and the valve seat can not be closed, resulting in unstable pilot flow, pressure fluctuations and noise, which should be promptly repaired or replaced.
③Pilot valve due to spring fatigue and deformation caused by the unstable function of the pressure regulator, making the pressure fluctuations caused by noise, the spring should be replaced.
02.Noise of hydraulic cylinder
①Air mixed in the fluid or hydraulic cylinder air is not completely exhausted, under the action of high pressure to produce cavitation phenomenon and cause greater noise. At this point, the air must be exhausted in a timely manner.
②Cylinder head oil seal is too tight or piston rod bending, in the process of movement will also produce noise due to holding power. At this time, it is necessary to replace the oil seal or straighten the piston rod in time.
03. Piping noise
Too many dead bends in the pipeline or loose fixed clamps can also produce vibration and noise. Therefore, in the pipeline arrangement should try to avoid dead bends, the loose clamps must be tightened in time.
04. Noise of hydraulic pump or hydraulic motor
① Air absorption phenomenon is one of the main reasons for excessive noise of hydraulic pump. When the oil mixed with air, easy to form cavitation phenomenon in its high-pressure area, and propagated in the form of pressure waves, resulting in oil oscillation, resulting in the system to produce cavitation noise. Its main reasons are:
- (1)Hydraulic pump oil filter, oil inlet pipe clogging or oil viscosity is too high, can cause the pump inlet vacuum is too high, so that air infiltration.
(2)Hydraulic pump, pilot pump shaft end oil seal damage, or poor sealing of the inlet pipe, resulting in air entry.
(3)The oil level of the oil tank is too low, so that the hydraulic pump inlet pipe directly sucks air. When the hydraulic pump works with high noise, the above parts should be checked first, and the problem should be dealt with in time.
②Excessive wear of internal components of the hydraulic pump, such as piston pump cylinder and flow distribution disk, plunger and plunger hole and other mating parts of the wear, strain, so that the hydraulic pump internal leakage is serious, when the hydraulic pump output high-pressure, small flow of oil will produce flow pulsation, triggering higher noise. At this time, you can appropriately increase the deflection angle of the pilot system variable mechanism, in order to improve the internal leakage on the pump output flow.
Hydraulic pump servo valve spool, control the flow of the piston will also be due to localized wear and tear, strain, so that the piston in the process of moving pulsation, resulting in fluctuations in the output flow and pressure of the hydraulic pump, thus generating a large vibration and noise at the pump outlet. At this time, wear, strain serious components can be brushed and plating research and development or replacement processing.
③Hydraulic pump flow distribution disk is also easy to trigger the noise of one of the important components. Distributor disk in use due to surface wear or sludge deposits in the unloading tank open, will make the unloading tank shorten and change the unloading position, resulting in oil trapping phenomenon, which in turn triggered a high noise.
In the normal repair process, the flat grinding repair of the flow distribution disk will also appear in the unloading slot shortened consequences, at this time, if not in a timely manner will be appropriate to repair the length, will also produce greater noise.
In the assembly process, the large unloading groove of the flow distribution disk must be installed in the high pressure chamber of the pump, and the direction of its sharp angle and the rotation of the cylinder body must be relative, otherwise, it will also bring greater noise to the system.
