(1) Wear: friction between the moving pairs of mechanical parts such as hydraulic valve core, valve sleeve, valve body, etc., constantly generates friction during use, which makes the size, shape and surface quality of the parts change and fail.
(2) Fatigue: When 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 valve core and valve seat will also be fatigued, resulting in cracks, peeling or other damage. These all have the potential to cause the valve to fail.
(3) Deformation: When the residual stress of hydraulic valve parts during processing and the external load stress during use exceed the yield strength of the part material, the parts are deformed and fail to complete their normal functions.
(4) Corrosion: The hydraulic oil is mixed with too much water or acidic substances. After long-term use, it will corrode the relevant parts in the hydraulic valve, causing it to lose its due precision and fail.
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 causes the spool to be stuck, which is called “hydraulic clamping”.
3. Hydraulic shock
Due to the rapid reversal or closing of the oil passage in the hydraulic system, the oil flowing in the system suddenly changes direction or stops flowing, causing the pressure to rise sharply, forming a large pressure peak, which is hydraulic shock.
4. Cavitation phenomenon
In hydraulic systems, the phenomenon of air bubbles caused by pressure drop caused by changes in liquid flow rate is called “cavitation”. Cavitation and cavitation deteriorate hydraulic system performance and reduce reliability.
To sum up, the mechanical failure of hydraulic valves is mainly related to management in addition to processing and manufacturing factors, so don’t wait until the hydraulic system fails to work properly. Usually, more pre-judgment and pretreatment are needed to eliminate equipment failures caused by valve failures in the bud.