"Crawling" is an abnormal movement state that often occurs in the hydraulic transmission of full-automatic mixer. Slight "crawling" causes the moving parts to vibrate imperceptibly, while significant "crawling" causes the moving parts to jump at a large distance. Creeping phenomenon is very harmful, so eliminating "creeping" phenomenon is very important to improve the stability of hydraulic system and improve the machining accuracy of machine tools.
"Creeping" caused by poor driving rigidity
After the air enters the oil, part of it will dissolve in the pressure oil, and the rest will form bubbles to float in the pressure oil. Because the air has compressibility, the hydraulic oil has obvious elasticity, resulting in poor driving rigidity and "crawling".
When manufacturing and repairing parts, the tolerance requirements shall be strictly met, and the fit clearance shall be ensured during assembly. Tighten the connections of all pipelines to prevent leakage. Tighten the connecting screws at all joint surfaces evenly, and the sealing gasket shall be uniform. Multi layer paper pads are not allowed. The oil filter with sufficient capacity shall be used to remove the dirt attached to the oil filter. Improve the hydraulic system, try to prevent local vacuum in the system, and set necessary vent plug or vent valve.
"Creeping" caused by large clearance of hydraulic components
When the moving part moves at low speed, once dry friction occurs, the resistance increases. At this time, the hydraulic pump is required to increase the pressure, but due to the large clearance of the hydraulic pump and serious oil leakage, it can not adapt to the pressure change of the actuator due to the change of resistance, resulting in "crawling".
Repair or replace the parts in the hydraulic pump to ensure the clearance required for assembly, so as to reduce the leakage of the hydraulic pump.
"Crawling" caused by control valve failure: the damping holes and throttles of various control valves are blocked by dirt, and the valve core is not flexible to move, which makes the pressure fluctuate greatly, resulting in "crawling" due to large thrust or small flow.
Keep the oil clean, clean and replace regularly, and strengthen the maintenance of components to prevent hydraulic oil pollution.
"Creep" caused by friction resistance change
The manufacturers of full-automatic mixer truck believe that this phenomenon occurs more in the hydraulic cylinder, mainly because the center line of the hydraulic cylinder is not parallel to the piston rod, the piston rod is partially or fully bent, the inner circle of the cylinder barrel is roughened and scratched, the accuracy of the cylinder barrel cannot meet the technical requirements, and the oil seals at both ends of the piston rod are adjusted too tightly, which will cause "crawling".
Inspect the accuracy and damage of the hydraulic cylinder item by item, and repair or update it. The installation accuracy of hydraulic cylinder shall meet the technical requirements.
The above is the relevant introduction to the problem. I hope it can help you. You can follow our website www.zkzdsljbc COM, for more detailed information, our professional customer service staff will also provide you with good service!