The hydraulic cylinder cannot drive the load when it is working. The main manifestations are inaccurate stop of the piston rod, insufficient thrust, speed drop, and unstable work. What is the reason why the ydraulic cylinder cannot drive the load when working:
(1) Internal leakage of hydraulic cylinder. The internal leakage of the hydraulic cylinder includes the leakage caused by the hydraulic cylinder body seal, the seal of the piston rod and the seal cover, and the excessive wear of the piston seal.
The reason for the leakage of the piston rod and the sealing cover of the hydraulic cylinder is that the seal is wrinkled, squeezed, torn, worn, aging, deteriorated, deformed, etc. At this time, a new seal should be replaced.
The main reason for excessive wear of the piston seal of the hydraulic cylinder is improper adjustment of the speed control valve, resulting in excessive back pressure and improper installation of the seal or contamination of the hydraulic oil. The second is that foreign matter enters during assembly and the quality of the sealing material is not good. The consequence is slow movement and weakness. In severe cases, it will cause damage to the piston and cylinder, causing the phenomenon of "cylinder pulling". The treatment method is to adjust the speed control valve, and make necessary operations and improvements according to the installation instructions.
(2) The hydraulic cylinder hydraulic circuit leaks. Including leakage of valves and hydraulic lines. The maintenance method is to check and eliminate the leakage of the hydraulic connection pipeline by operating the reversing valve.
(3) The hydraulic oil of the hydraulic cylinder is bypassed back to the oil tank through the overflow valve. If dirt enters the overflow valve and jams the spool, making the overflow valve normally open, the hydraulic oil will bypass the overflow valve and directly flow back to the oil tank, causing the hydraulic cylinder to run out of oil. If the load is too large, although the regulating pressure of the relief valve has reached the maximum rated value, the hydraulic cylinder still cannot get the thrust required for continuous action and does not move. If the adjustment pressure is low, the vertebral force required for still loading cannot be achieved due to insufficient pressure, which is manifested as insufficient thrust. At this time, check and adjust the overflow valve.
