Solution to low speed crawling problem of hydraulic cylinder of cutting machine
First, the oil pressure cutting machine hydraulic cylinder has the low speed crawling produced by the rod cavity and the non rod cavity, and can achieve the exhaust by repeatedly running the hydraulic cylinder. When necessary, the exhaust device is set in the two cavity of the pipe or the hydraulic cylinder, and the exhaust is carried out in the hydraulic system.
Second. The low speed crawling produced by the improper design clearance of hydraulic cylinder hydraulic cylinder can correctly design the sliding fit gap between the piston and the cylinder body, the piston rod and the guide sleeve in the hydraulic cylinder. The theoretical matching clearance is H9 / N or H9 / F8, and also H8 / F8; according to the experience of the author, the hydraulic cylinder is the hydraulic cylinder. The cylinder diameter and rod diameter from small to large, such as according to the design of the gap, for larger cylinder diameter (> 200mm) and the gap between the diameter of the rod (> 140mm), the gap is too large, in the actual process, the hydraulic cylinder at low speed crawling smaller cylinder hydraulic cylinder appears more, foreign such hydraulic cylinders. The joint clearance of the sliding surface is generally designed to be 0.05mm 0.15mm. From the actual comparison, the problem of low speed crawling of the hydraulic cylinder is obviously improved. The hydraulic cylinder on the large diameter and suggested the use of this method
Third. It is suggested that metal be used as a guide support, such as QT500 7, ZQAL9 4, etc., such as non metal support ring, which is a non metal support ring, especially thermal expansion. The coefficient should be small. Besides, for the thickness of the supporting ring, we must strictly control the size tolerance and the uniformity of the thickness.
Fourth. As to the low speed crawling of the hydraulic cylinder of the cutting machine caused by the seal material problem, it is suggested that the polytetrafluoroethylene as the sealed sealing ring, such as the common grill ring and the sterling seal, should be preferred under the conditions permitted by the working conditions, such as the seal of the lip and the seal of the lip, the material is preferred to choose the seal of butadiene rubber or similar material. It is better to follow.
Fifth. The influence of the machining precision of parts and parts, in the manufacturing process of the hydraulic cylinder, the machining precision of the inner wall of the cylinder and the piston rod should be strictly controlled, especially the geometric precision, especially the straightness is the key. In the domestic processing technology, the machining of the piston rod surface is basically the rear grinding to ensure the straightness. But for the inner wall of the cylinder, there are many processing methods, such as boring - rolling, boring - honing, direct honing, etc., but because of the difference in the basic level of the domestic material, the straightness of the blank, the uneven thickness of the wall, the uneven hardness of the wall and so on, often affect directly the straight of the inner wall of the cylinder. Therefore, it is suggested that boring, rolling, boring and honing processes, such as direct honing, must first improve the straightness of tube billets.