Low Speed Problem Of Hydraulic Cylinder Of Cutting Machine

- Dec 14, 2020-

1. Hydraulic cylinder of hydraulic pressure cutting machine has low speed creep caused by the existence of gas in the rod cavity and without the rod cavity. The purpose of exhaust can be achieved through repeated running of the hydraulic cylinder.

2. Low speed creep caused by improper design clearance of hydraulic cylinder of hydraulic cutting machine can correctly design sliding fit clearance between piston and cylinder body, piston rod and guide sleeve inside hydraulic cylinder. Theoretically, fit clearance is H9 / N or H9 / F8, and there are also H8 / F8; According to the author's experience, the cylinder diameter and rod diameter of the hydraulic cylinder are from small to large, if the fit clearance is designed according to this, for the larger cylinder diameter (≥? 200 mm) and stem diameter (140 mm) or higher fit clearance gap is too big, actually should process, this kind of hydraulic cylinder at low speed crawl phenomenon appear smaller diameter hydraulic cylinder, such hydraulic cylinder fitting clearance of the slip plane with the general design abroad ∽ 0.15 mm and 0.05 mm from the point of the results of actual comparison, the hydraulic cylinder of low-speed crawling problem obviously improved. Therefore, this method is recommended for large diameter hydraulic cylinders

3. Guide element within three, cutting machine, hydraulic cylinder friction uneven produced by low speed crawl, preferred with metal as the guide, such as QT500-7, ZQAL9-4, such as using non-metallic support ring, choose the dimensional stability in oil good advice non-metallic support ring, especially the thermal expansion coefficient should be small, in addition to the thickness of the support ring, must strictly control the uniformity of size tolerance and thickness.

4. For the low speed creep of the hydraulic cylinder of the cutting machine caused by the material problem of sealing parts, it is suggested that teflon is preferred as the sealing combination sealing ring, such as the commonly used greyring and Steppe seal, etc. under the permissible working conditions; If the lip seal is chosen, it is recommended to choose butadiene rubber or similar material seals, which have good follow - up.

5, the influence of the precision parts processing, in the manufacturing process of hydraulic cylinder hydraulic cutting machine should strictly control the cylinder wall and piston rod surface machining accuracy, especially the geometric accuracy, especially the straightness is the key, in the domestic processing technology, processing on the surface of the piston rod is basically a car after grinding, ensure straightness problem is not big, but for the inner wall of the cylinder block processing, the processing method are many, boring, rolling, boring - direct honing honing, etc, but due to the basic level of domestic materials, compared with foreign gap pipe blank straightness error, uneven uneven thickness, hardness and other factors, It often directly affects the straightness of the inner wall of the cylinder block, so it is recommended to adopt boring - rolling and boring - honing technology, such as direct honing, the straightness of the pipe blank must be improved first.