Hydraulic cylinder design purpose is based on the site working temperature, working medium and factory processing conditions. According to the mechanical design manual, calculate the size of the internal structure.
1. The selection of sealing must be based on the site working temperature, environmental pollution, working medium to choose. The water-glycol medium cannot be sealed with polyurethane.
2. The cylinder head of the cylinder adopts V-type combination seal as far as possible, which can make up for the error of the finish of the groove processing.
3. The size of the sealing groove is designed in strict accordance with the design manual.
4. The piston seal of the cylinder generally uses Gray ring plus guide belt, Gray ring has good high temperature resistance and pollution resistance.
5. The cylinder seal is generally made of Japanese NOK series. Do not use domestic cylinder seals, otherwise the cylinder starts resistance is too large, the action is not smooth or even does not work.
6. The O-ring seal between the head and the bottom of the cylinder of the cylinder, and it is best to add a retaining ring, so as to make up for the processing error.
7. The connection between cylinder, cylinder head and bottom as well as the middle swing should not be welded as far as possible, because welding will cause cylinder deformation. Thread connection or other connection methods can be used.
Hydraulic cylinder common problems and maintenance
Hydraulic cylinder oil leakage
External leakage refers to the oil leakage from the seal is not strict to the atmosphere outside the hydraulic cylinder, the most common external leakage has the following three places:
(1) Oil leakage in the sealing part of the hydraulic cylinder liner and the cylinder head (or guide sleeve) (Solution: replace the new O-ring);
(2) The piston rod and guide sleeve surface relative movement to the external oil leakage (solution: if the piston rod has damage, it can be cleaned with gasoline, after drying with metal glue smeared on the damage, and then use the piston rod oil seal to move back and forth on the piston rod to scratch the excess glue, such as glue fully cured before being put into use. If the guide sleeve wear, can be processed a slightly smaller guide sleeve to replace);
(3) Oil leakage caused by lax sealing of hydraulic cylinder pipe joint (Solution: in addition to checking the sealing of the sealing ring, it should also check whether the joint is correctly assembled, whether it is reliably tightened and whether the contact surface is scarred, etc., replace or repair if necessary)
Hydraulic cylinder leakage refers to the leakage of oil from the high pressure chamber to the low pressure chamber through various gaps in the hydraulic cylinder. Internal leakage is more difficult to detect, only through the system operating conditions, such as insufficient thrust, speed decline, unstable work or high oil temperature rise to judge. Hydraulic cylinder leakage generally has the following two places:
(1) The static sealing part between the piston rod and the piston (solution: install O-ring on the sealing surface of both);
(2) The dynamic seal between the inner wall of the cylinder liner and the piston (Solution: When internal leakage is found, strict inspection should be carried out on the matching parts first. The repair of cylinder liner adopts the method of boring the inner hole, and then matched with the enlarged diameter of the piston);
