Noise Analysis Of Hydraulic Valve
Noise analysis of hydraulic valve
1. Noise of plunger pump or motor
(1) The phenomenon of air absorption is one of the main causes of high noise of hydraulic pump. When the oil is mixed with air, it is easy to form cavitation phenomenon in the high-pressure zone, and it is transmitted in the form of pressure wave, which causes the oil oscillation and the system produces cavitation noise.
The main reasons are:
1. Hydraulic Pump oil filter, plugging into the tubing or oil viscosity too high, can cause the pump into the mouth of the vacuum through high, hydraulic valve so that air infiltration.
2. The hydraulic pump, the pilot pump shaft end oil seal damage, or enters the tubing seal to be bad, causes the air to enter o 3. The oil tank is too low to make the hydraulic pump enter the tubing directly.
When the hydraulic pump is in high noise, the above parts should be inspected first and the problem should be dealt with in time.
(2) Excessive abrasion of internal components of hydraulic pump, such as plunger pump cylinder and flow plate, plunger and column female and other parts of the wear and tear, so that the leakage of hydraulic pump is serious, hydraulic valve when the hydraulic pump output high-pressure, small flow of oil will produce flow pulsation, triggering higher noise. At this time, the deflection angle of the pilot system variable mechanism can be enlarged to improve the effect of internal leakage on pump output flow.
Hydraulic Pump servo valve spool, control flow piston will also be due to local wear, tensile injury, so that the piston in the movement of the pulse, resulting in the hydraulic pump output flow and pressure fluctuations, so that the pump at the exit to produce greater vibration and noise. At this time can wear, pull the serious components of the brush plating or replacement treatment.
(3) The hydraulic pump plate is also one of the important components that easily cause noise. In the use of the flow plate due to surface wear or sludge deposition in the unloading groove opening, will make the unloading Groove shorten and change the unloading position, resulting in the phenomenon of trapped oil, hydraulic valve and then lead to higher noise. In the normal repair process, the flat grinding repair of the flow plate will also appear to be short of the consequences of unloading slots, at this time if not in time to the appropriate slender, will also produce greater noise. In the assembly process, the large unloading groove of the flow plate must be installed in the high-pressure cavity of the pump, and its sharp angle direction and the cylinder body's rotation must be opposite, otherwise it will bring the big noise to the system.
2. Noise of overflow valve
Overflow valve is easy to produce high-frequency noise, mainly caused by the unsteady performance of the pilot valve, that is, the noise caused by the high frequency oscillation of the front cavity pressure of the pilot valve.
The main reasons are:
(1) Mixing the air in the oil liquid, forming the cavitation phenomenon in the front cavity of the pilot valve and causing the high-frequency noise. At this time, the air should be discharged in time to prevent the outside air to re-enter.
(2) needle valve in the use of the process due to frequent opening and excessive wear, so that the needle valve cone and valve seat can not be closed, resulting in a pilot flow instability, resulting in pressure fluctuations caused by noise, hydraulic valve it should be repaired or replaced in time.
(3) The pilot valve due to the spring fatigue deformation caused by the instability of its voltage regulator, making the pressure fluctuation big and caused by noise, the spring should be replaced.
3. The noise of the hydraulic cylinder
(1) in the oil liquid mixed with air or hydraulic cylinder in the air is not fully discharged, under high pressure to produce cavitation phenomenon caused by greater noise. hydraulic valve At this time, the air must be discharged in time.
(2) The cylinder oil is sealed too tightly or the piston rod bends, in the movement process also may cause the noise by the strength. At this point, the timely replacement of oil seals or straightening piston rod.
4. Pipe noise
Too much die bending or a fixed clamp can also generate vibration and noise. Therefore, in the pipeline layout should try to avoid dead bends, hydraulic valve to loosen the clamp must be tightened in time.