Excavator cylinder crawling, check these places right
In fact, every excavator is shipped from the factory, and there are certain quantitative specifications for this crawl index. The ambition is best not to crawl. However, in the actual production process, it is difficult to reach. Therefore, the “upper limit and lower limit of the specification” are set. Only when When this “crawling amount” exceeds the upper and lower limits, it can be determined that the digging machine is defective.
Of course, each manufacturer has its own specifications for each manufacturer, and each one has its own difference, that is, the size of the cylinder and the bucket cylinder are not the same.
Only when this “crawling amount” exceeds the upper and lower limits, then the excavator can be determined to be defective. What is the cause of the problem?
The cause of the crawling phenomenon is due to reasons other than the hydraulic cylinder and the hydraulic cylinder itself.
1, check whether the cylinder into the air:
a. If air is mixed in the oil and air is drawn from the hydraulic pump, the air pump inlet air can be removed first.
b. For cylinders with new hydraulic cylinders, repaired hydraulic cylinders, or equipment that have been shut down for too long, there will be air in the cylinders and pipes.
It can be exhausted by the air vent plug of the hydraulic cylinder. For hydraulic cylinders without special exhaust devices, the inlet and outlet pipe joints of the two ends of the hydraulic cylinder can be slightly loosened first, and the hydraulic cylinder can be reciprocated several times to exhaust.
If the oil leaking from the joint is changed from cloudiness to clearness, it indicates that the air has been cleaned and the pipe joints can be tightened from the head.
For hydraulic cylinders that are difficult to drain with this method, the air can be exhausted by loading the exhaust gas and filling the cylinder with oil.
c. In the case of negative pressure in the cylinder and easy to draw air from the piston rod, pay attention to the rationality of the piston rod seal planning.
d. After starting the machine, let the hydraulic cylinder run for 10 minutes at the maximum stroke and maximum speed to force the gas to discharge.
2, check whether the hydraulic cylinder due to poor installation accuracy:
It should improve the installation quality of hydraulic cylinders.
For example, when the piston rod and the piston do not have the same center of mind, the coaxiality is calibrated; when the piston rod is bent, the piston rod is straightened, and the cooperation between the piston rod and the guide sleeve is selected by the cooperation of H8/F8. The use of the regular manufacturer is strictly required by the standard and quality specifications. When the seal ring or V-ring is selected, the seal friction should be adjusted to a moderate degree.
3, check the hydraulic cylinder cover seal is too tight or too loose:
Adjust the sealing ring so that it is neither tight nor loose, the guide sleeve is concentric, ensuring that the piston rod can be moved back and forth by hand (or tapped only with a hammer), while the piston rod is slightly covered with a film of oil.
4, check whether the hydraulic cylinder installation accuracy is poor:
If the load and the piston rod connection point as close as possible to the sliding surface of the guide rail; the piston rod axis line and the load center line strive to be common; the length of the touch with the guide rail should be as long as possible; load and the hydraulic cylinder connection position should be the thrust of the hydraulic cylinder is not Make sure that the load is skewed; the guidance is better, the machining accuracy and installation accuracy are better, and watch for smoothness.
5, check whether the guide rail production and installation of poor quality, smooth and bad, etc.:
Can be adopted to clean and smooth the slide guide, adjust the smooth pressure and smooth flow from the head, apply a layer of anti-creep oil (such as molybdenum disulfide smooth oil) between the relative movement surface of the guide rail, etc., and scrape the guide rail from the head if necessary.