How to choose oil seal?
When choosing an oil seal, first pay attention to its model and specification (i. e. inner diameter, outer diameter and thickness). Oil seal specifications are generally marked on the oil seal, i.e. outer diameter × inner diameter × thickness, in mm. If no marked can be measured with vernier caliper, when buying oil seal, check its quality. First, see whether the appearance is smooth and bright, fine workmanship, with the finger extrusion outside diameter and a certain degree of hardness and rigidity, but also a certain degree of flexibility. On the contrary, the appearance of rough hair dark, quality must have problems.
The lip of the oil seal should be smooth and even, without burr, and the tension spring should be free from rust and have good pulling force. When the lip is pulled with finger hook, it has certain elasticity and does not deform. When the oil seal is scratched on the floor tile, wood or hard object, it is a quality problem if the scratch is thicker, darker or more obvious. On the contrary, no obvious scratches after delimit, oil seal is still smooth and lossless generally for better quality.
When selecting the oil seal material, the compatibility of the material to the working medium, the adaptability to the working temperature range and the ability of the lip edge to follow the rotation axis at high speed must be considered. Generally, the temperature of the lip edge of the oil seal is 20~50℃ higher than that of the working medium. The operating range of oil seals is related to the materials used: -40~120℃ for nitrile butadiene rubber (NBR), -30~180℃ for Alec rubber (ACM), -25~300℃ for fluororubber (FPM).
How to install oil seal?
Before oil seal assembly should be the groove of the oil seal, with a scraper, saw blade and other things will be removed when the burr and trauma flat, scrape, and then touch the edge with your finger, if no burr can be felt.
Remove the iron filings and grease in the groove and shaft, wipe the dirt with a clean cloth, and then apply a little oil or grease to the inner diameter of the oil seal to facilitate oil seal loading.
If the oil seal feels too tight when loading, do not force it in, otherwise, it will cause deformation of the oil seal and damage the outer diameter, affecting its sealing property. If necessary, use wood file to file the outer diameter gently (when filing, it should prevent looseness and repeatedly measure), or further check and remove impurities and foreign bodies in the oil seal groove.
After the oil seal is loaded, check whether it is in place. First, observe the depth of the oil seal in the groove to see whether there is any deviation. The second is to observe the size of the gap between the inner diameter of the oil seal and the shaft to judge, the gap is large, load more, small gap, load less, at this time should be timely correction, to prevent oil leakage caused by deviation.
In addition, if there is no oil seal of the same model in the assembly, the specification and model are less different to replace it. When the outer diameter is larger, it can be filed for processing. When the outer diameter is smaller, it can be dried by applying a little glue on the outer diameter, or wrapping adhesive cloth to increase the processing.
Inner diameter is generally allowed small not big, but not too tight, otherwise cause friction too large, accelerate oil seal damage, and finally check its oil seal, to the lip coating soapy water and oil inspection, start the engine if there are bubbles out, can conclude that there is oil leakage, leakage phenomenon exists. Finally, according to the situation to deal with.