Hydraulic valve is almost an indispensable hydraulic component in all hydraulic systems, hydraulic valve plays a role in the control of the speed, direction and pressure of the actuator in the hydraulic system, hydraulic valve failure will have a huge impact on the entire hydraulic system, and even directly lead to the hydraulic system can not run or crash accident, today, the hydraulic valve failure is more concentrated phenomenon as a starting point, The failure reasons of hydraulic valve are briefly summarized, hoping to provide some reference for everyone.
Hydraulic valve failure of the 4 major reasons and corresponding preventive measures
1. Hydraulic valve failure reasons
1) Mechanical failure
(1) Wear: The moving pairs of hydraulic spool, valve sleeve, valve body and other mechanical parts continue to produce friction during use, making the size, shape and surface quality of the parts change and fail.
(2) Fatigue: working under long-term variable load, the spring in the hydraulic valve will become soft due to fatigue, shorten the length of the spring or break the whole; The spool and seat will also be cracked, spalling or other damage due to fatigue. These can cause the valve to fail.
(3) Deformation: When the residual stress of the hydraulic valve parts in the processing process and the external load stress in the use process exceed the yield strength of the parts material, the parts are deformed and can not complete the normal function and fail.
(4) Corrosion: the hydraulic oil is mixed with too much water or acidic substances, and after long-term use, it will corrode the relevant parts of the hydraulic valve, making it lose its due accuracy and failure.
Hydraulic valve failure of the 4 major reasons and corresponding preventive measures
2), hydraulic clamping
When the pressure oil flows through the cylindrical slide valve structure of the hydraulic valve, the radial unbalanced force acting on the spool makes the spool stuck, which is called "hydraulic clamping".
Hydraulic valve failure of the 4 major reasons and corresponding preventive measures
3), hydraulic shock
Due to the rapid reversal or closure of the hydraulic system, the oil flowing in the system suddenly reverses or stops flowing, causing a sharp rise in pressure and forming a large pressure peak, that is, hydraulic shock.
4) Cavitation phenomenon
In the hydraulic system, the phenomenon of bubbles caused by the pressure drop caused by the change of liquid flow rate is called "air pocket". Cavitation and cavitation make the performance of hydraulic system deteriorate and the reliability decrease.
Hydraulic valve failure of the 4 major reasons and corresponding preventive measures
2. Corresponding preventive measures
1) The mechanical failure of the hydraulic valve has a large relationship with the design of the valve and the processing of the parts, so the preventive measures we can take in maintenance are relatively limited
2) Improve the cleanliness of hydraulic oil, help to reduce the spool due to impurities caused by the stuck phenomenon, install the spool screw screw as far as possible according to the design requirements, avoid due to force deformation caused by the spool stuck, pay attention to the oil temperature of hydraulic oil, as far as possible to avoid the deformation caused by excessive temperature change, because the gap between the spool and the valve body is very small, a little deformation may lead to poor operation and stuck.
3) In the case of not affecting the rhythm, try to slow down the switching speed of the reversing valve, you can also install a suitable damping (throttle) to slow down the switching speed, so as to extend the switching time and reduce the impact, you can also increase the accumulator to absorb the impact, reduce the impact, with a hose instead of a hard tube can also play a cushioning role to a certain extent.
4) Reducing the content of air in hydraulic oil can greatly reduce the occurrence of air pockets, so it is necessary to pay attention to the sealing of the pump and the sealing of the joints in the pipeline to ensure that there is no leakage, reduce the probability of adding air into the oil, and ensure that the suction pipe is smooth, ensure that the suction pressure is greater than the air separation pressure, and prevent the oil from mixing water and other volatile substances.
In summary: the mechanical failure of hydraulic valve in addition to processing and manufacturing factors, mainly related to the management and maintenance of hydraulic equipment, so do not wait until the hydraulic system can not work properly. Usually, more pre-judgment and pretreatment should be done to eliminate equipment failures caused by hydraulic valve failure in the bud.
