Causes of hydraulic cylinder piston slippage failure

After the hydraulic cylinder has been used for a period of time, some failures will cause the cylinder to work unstable, such as the sliding or crawling of the piston of the hydraulic cylinder. Here is an analysis of the causes of the failure of the piston slip of the hydraulic cylinder.

    1. The hydraulic pump or hydraulic cylinder enters the air. Compression or expansion of air will cause the piston to slip or crawl. The troubleshooting measures are to check the hydraulic pump, set up a special exhaust device, and quickly operate the exhaust for several times throughout the entire stroke.

    2. Poor lubrication or poor machining of hydraulic cylinder bores. Because the piston and the cylinder barrel, the guide rail and the piston rod have relative motion, if the lubrication is poor or the hydraulic cylinder bore is too poor, it will aggravate the wear and reduce the linearity of the cylinder barrel. In this way, when the piston is working in the hydraulic cylinder, the frictional resistance will be large and small, causing slippage or crawling. The elimination method is to grind the hydraulic cylinder first, then prepare the piston according to the matching requirements, grind the piston rod, and configure the guide sleeve.

    3. The inside of the hydraulic cylinder is stagnant. The internal parts of the hydraulic cylinder are improperly assembled, the parts are deformed, worn, or the geometric tolerance exceeds the limit, and the action resistance is too large, so that the piston speed of the hydraulic cylinder changes with the stroke position and slips or crawls. The reason is mostly due to poor assembly quality of parts, scars on the surface or iron filings produced by sintering, which increase resistance and reduce speed. For example: the piston and the piston rod are not concentric or the piston rod is bent, the installation position of the hydraulic cylinder or the piston rod on the guide rail is offset, the sealing ring is installed too tightly or too loosely, etc. The solution is to repair or adjust again, replace damaged parts and remove iron filings.

    4. The quality of the seal is directly related to slippage or crawling. When the O-shaped seal is used under low pressure, compared with the U-shaped seal, due to the higher surface pressure and the larger difference in dynamic and static friction resistance, it is easy to slip or crawl; the surface pressure of the U-shaped seal increases with the pressure However, although the sealing effect is correspondingly improved, the difference between dynamic and static friction resistance also becomes larger. The internal pressure increases, which affects the elasticity of the rubber. As the contact resistance of the lip increases, the sealing ring will tip over and the lip will elongate, which is also easy In order to prevent slippage or crawling, a support ring can be used to keep it stable.