The solution to hydraulic cylinder crawling at low speed

The low-speed crawling caused by gas in the rod cavity and rodless cavity of the hydraulic cylinder can be exhausted by repeatedly operating the hydraulic cylinder. If necessary, set an exhaust device in the pipeline or the two chambers of the hydraulic cylinder to work in the hydraulic system Exhaust at time.

For low-speed crawling caused by uneven friction of the guiding elements in the hydraulic cylinder, it is recommended to use metal as the guiding support first, such as QT500-7, ZQAL9-4, etc. If a non-metallic support ring is used, it is recommended to use a good dimensional stability in the oil The non-metallic support ring, especially the coefficient of thermal expansion, should be small. In addition, the thickness of the support ring must be strictly controlled in terms of dimensional tolerance and thickness uniformity.

The machining accuracy of parts and components should be strictly controlled during the manufacturing process of the hydraulic cylinder, especially the geometric accuracy, especially the straightness is the key. In the domestic machining process, the machining of the piston rod surface should be strictly controlled. Basically, it is grinding after turning, ensuring straightness is not a big problem, but for the processing of the inner wall of the cylinder, there are many processing methods, including boring-rolling, boring-honing, direct honing, etc., but due to the basis of domestic materials There is a gap in level compared with foreign countries. Factors such as poor straightness of pipe blanks, uneven wall thickness, uneven hardness, etc., often directly affect the straightness of the inner wall of the cylinder after processing. Therefore, it is recommended to use the boring-rolling, boring-honing process. For direct honing, the straightness of the tube blank must first be improved.

For low-speed crawling of hydraulic cylinders caused by seal material problems, it is recommended to use polytetrafluoroethylene as the sealing combination seal ring, such as the commonly used Glyy ring, Ster seal, etc., when the working conditions permit. For the lip seal, it is recommended that the material is preferably nitrile rubber or similar seals, which have better followability. If the wall thickness of the hydraulic cylinder is allowed, the safety factor should be selected as large as possible to increase the thickness of the cylinder, especially the cylinder used under high pressure conditions to reduce the deformation of the cylinder under oil pressure. The cylinder body will also cause the hydraulic cylinder to crawl at low speed.