Introduction to the Noise Causes of Hydraulic Parts

1. Noise of hydraulic cylinder (1) The oil is mixed with air or the air in the hydraulic cylinder is not completely exhausted, and cavitation occurs under the action of high pressure, which causes large noise. At this time, the air must be exhausted in time. (2) If the oil seal of the cylinder head is too tight or the piston rod is bent, noise will also be generated due to different strength during the movement. At this time, it is necessary to replace the polyurethane oil seal or straighten the piston rod in time. 2. The noise of the plunger pump or motor (1) The phenomenon of air suction is one of the main reasons for the excessive noise of the hydraulic pump. When air is mixed into the oil, it is easy to form cavitation in its high-pressure area, and it spreads in the form of pressure waves, causing the oil to oscillate and cause the system to produce cavitation noise. (2) The internal components of the hydraulic pump are excessively worn, such as the wear and tear of the matching parts such as the cylinder block and the valve plate of the plunger pump, the plunger and the plunger hole, which cause serious leakage in the hydraulic pump. When the oil is flowing, flow pulsation will be generated, causing high noise. At this time, the deflection angle of the variable mechanism of the pilot system can be appropriately increased to improve the influence of internal leakage on the output flow of the pump. The servo valve spool of the hydraulic pump and the piston that controls the flow will also pulsate due to local wear and tear, causing the piston to pulsate during the movement process, resulting in fluctuations in the output flow and pressure of the hydraulic pump, resulting in greater vibration and noise at the pump outlet. . At this time, brush plating, grinding, or replacement can be performed on the components that are severely worn and strained. (3) The hydraulic pump distribution plate is also one of the important components that easily cause noise. When the valve plate is in use, due to surface wear or sludge deposits on the opening of the unloading groove, the unloading groove will be shortened and the unloading position will be changed, resulting in the phenomenon of trapped oil, which will cause higher noise. In the normal repair process, the distribution plate repaired by flat grinding will also have the consequence of shortening the unloading groove. During the assembly process, the large unloading groove of the valve plate must be installed in the high pressure chamber of the pump, and the direction of the sharp corner must be opposite to the rotation direction of the cylinder, otherwise it will bring greater noise to the system. 3. Noise of overflow valve The overflow valve is prone to high-frequency noise, which is mainly caused by the unstable performance of the pilot valve, which is the noise generated by the high-frequency oscillation of the pressure in the front chamber of the pilot valve caused by air vibration. The main reasons are: (1) Air is mixed into the oil, which forms cavitation in the front cavity of the pilot valve and causes high-frequency noise. At this time, the air should be exhausted in time and the outside air should be prevented from re-entering. (2) The needle valve is excessively worn due to frequent opening during use, so that the needle valve cone surface and the valve seat cannot be tightly fitted, resulting in unstable pilot flow, pressure fluctuations and noise. At this time, it should be repaired or replaced in time. (3) The pressure regulating function of the pilot valve is unstable due to the fatigue deformation of the spring, which makes the pressure fluctuate greatly and causes noise. At this time, the spring should be replaced. https://www.orksealing.com/