Solution Of Hydraulic Cylinder Crawling Low Speed Problem

- May 29, 2019-

1. The hydraulic cylinder of the hydraulic cutting machine has low-speed crawling caused by the presence of gas in the rod cavity and the rodless cavity. The purpose of exhausting can be achieved by repeatedly operating the hydraulic cylinder, and if necessary, exhausting is provided in the two chambers of the pipeline or the hydraulic cylinder. The device is vented while the hydraulic system is operating.

2. The low-speed crawling caused by the improper design of the hydraulic cylinder of the hydraulic cutting machine can correctly design the sliding fit clearance between the internal piston of the hydraulic cylinder and the cylinder block, the piston rod and the guide sleeve. The theoretical matching clearance is H9/N or H9/ F8, also has H8/f8; according to the author's experience, the cylinder diameter and rod diameter of the hydraulic cylinder are from small to large, as designed to match the clearance, for larger bore diameter (≥?200mm) and rod diameter (≥140mm The matching clearance is too large. In the actual process, the hydraulic cylinders of this type are crawling at a low speed. The cylinders with smaller cylinder diameters appear more frequently. The matching clearance of the sliding surfaces of such hydraulic cylinders is generally designed to be 0.05mm∽0. .15mm, from the actual comparison results, the low-speed crawling problem of the hydraulic cylinder is significantly improved. Therefore, it is recommended to use this method for large cylinder hydraulic cylinders.

3. Low-speed crawling caused by uneven friction of the guiding elements in the hydraulic cylinder of the cutting machine. It is recommended to use metal as the guiding support, such as QT500-7, ZQAL9-4, etc. If non-metallic support ring is used, it is recommended to use the size in the oil. The non-metallic support ring with good stability, especially the coefficient of thermal expansion should be small, and the thickness tolerance and thickness uniformity must be strictly controlled for the thickness of the support ring.