Analysis of hydraulic noise:
1 hydraulic pump or motor noise
(1) suction phenomenon is one of the main reasons for the high noise of hydraulic pump. When mixed with oil in the air, easy formation of cavitation in the high pressure region, and pressure wave form of communication, caused by oil shocks, resulting in cavitation noise generated.
The main reasons are:
1 hydraulic pump oil filter, oil inlet pipe plug or oil viscosity is too high, can cause the pump inlet is too high vacuum, so that air infiltration.
2 hydraulic pump, the pump shaft end seal damaged, or into the tubing seal, causing air to enter.
The 3 tank level is too low, the direct suction pump air into the pipeline.
When the hydraulic pump in the work of high noise, should be the first to check the above parts, found that the problem in a timely manner.
(2) the internal components of the hydraulic pump excessive wear, such as hydraulic pump cylinder and valve plate, and with blade rotor parts wear, tear, make a serious leak in the hydraulic pump, when the hydraulic pump output pressure and flow pulsation will produce small flow oil, causing high noise. This may be appropriate to increase the angle of the pilot system of variable mechanism, to improve the internal leakage of the pump output flow.
Hydraulic pump control flow of the piston will be due to local wear and tear, so that the piston in the moving process of pulsation, resulting in the output flow and pressure of the hydraulic pump fluctuations, resulting in greater vibration and noise at the pump outlet. At this time, wear and tear, a serious component of the brush plating research or replacement treatment.
(3) the hydraulic pump valve plate is easy to cause one of the important components of noise. The valve plate in use for surface wear or sludge deposition in the open unloading groove will make shorter unloading slot and change the unloading position, produce trapped oil phenomenon, sparking a high noise. In the normal repair process, by grinding flat valve plate repair will appear shorter unloading slot of the consequences, if not timely at this time due to its slender, will also have a greater noise. In the assembly process, the valve plate unloading tank must be installed in the high pressure cavity pump, and the cylinder rotation direction and angle relative to the need to, otherwise the system will also bring more noise.
2 overflow valve noise
Relief valve is easy to produce high frequency noise, mainly due to the pilot valve performance is not stable, that is, before the pilot valve cavity pressure high frequency oscillation caused by air vibration and noise.
The main reasons are:
(1) mixed with oil in the air, the pilot valve in the cavity prior to the formation of cavitation caused by high frequency noise. At this point, it should be timely discharge of air and prevent the re entry of the outside air.
(2) the needle in the process due to the frequent use of open and excessive wear, the cone valve and valve seat can not be closed, causing the pilot flow instability and pressure fluctuations caused by noise, this time should be timely repair or replacement.
(3) the pilot valve due to spring fatigue deformation caused by its pressure regulating function is not stable, so that the pressure fluctuations caused by noise, at this time should be replaced by the spring.
3 the noise of the hydraulic cylinder
(1) the oil mixed with air or hydraulic cylinders in air is not completely drained, cavitation phenomenon under high pressure caused by noise. At this time, must be timely exhaust air.
(2) the cylinder head or piston rod seal tight bend in the process of movement will be because of other strong noise. At this time, should be the timely replacement of oil seal or straightening piston rod.
4 pipe noise
The pipe bends too much or the fixing clips can also produce vibration and noise. Therefore, arrangements should be in the pipeline to avoid dead corner Nagarze to loose to be timely tightening.
Two, the hydraulic system vibration and noise generation causes and elimination measures
1, the source of vibration and noise caused by the vibration and noise sources in the hydraulic system a lot, generally have mechanical systems, hydraulic pumps, hydraulic valves and piping, etc.. Mechanical system vibration and noise mechanical system vibration and noise, mainly driven by the mechanical transmission of the hydraulic pump system, mainly in the following aspects.
1) rotational imbalance in the practical application, mostly through motor coupling drives the hydraulic pump to work, to make these rotary fully dynamic balance is very difficult, if the unbalanced force is too large, it will lead to bigger bending vibration of shaft in rotation and noise.
2) improper installation of hydraulic system is often installed on the existing problems, and cause vibration and noise. Such as the system of supporting pipeline and bad based defect or hydraulic pump and motor shaft, and loose coupling, which will lead to greater vibration and noise.
2 hydraulic pump (hydraulic motor) is usually the main hydraulic components of vibration and noise of the whole hydraulic system. The reason of vibration and noise of hydraulic pump, on the one hand is due to mechanical vibration, on the other hand is due to the accumulation of liquid flow and pressure changes.
1) cycle change of hydraulic pump pressure and flow
The hydraulic pump gear, vane and piston in the oil absorption process, oil pressure in the process of making the corresponding work produce periodic flow and pressure, changes in the working chamber corresponding to produce periodic flow and pressure, and cause the pump flow and pressure pulsation of hydraulic pump components caused by vibration while the component vibration has caused the vibration of contact with the air density change, and spread out the noise wave.
2) the cavitation of the hydraulic pump
The hydraulic pump at work, if the hydraulic oil suction pipe of the resistance is too large, the hydraulic oil to the oil absorption cavity less than full pump suction caused by cavity, partial vacuum, negative pressure is formed. If the pressure reaches the air separation pressure oil, the original air dissolved in fluid will precipitate the formation. The free state of the bubble pump. With this move,