1、the working principle of oil seal
1) free state under the oil seal lip diameter smaller than the journal has a certain amount of interference;
2) after the installation of the oil seal edge of the interference pressure and self-tightening of the spring force to deal with the rotation axis to produce a certain radial pressure;
3) Working oil seal lip under the action of radial pressure to form 0.25 ~ 0.5mm wide sealed contact ring. In the role of lubricating oil pressure, the oil into the oil seal edge, and the shaft between the formation of a very thin layer of oil film, the oil film by the role of surface tension in the shaft and oil seal edge edge to form a "new moon" To prevent the oil spill from sealing.
2、 the main factors that cause leakage of oil seal
Sealing of the oil seal is the main factor causing leakage. When the shaft appears to wear to form a groove, even if the replacement of the new oil seal can not be sealed because the oil seal lip and the contact pressure drop caused by the installation of oil seal lip diameter and journal clearance is too small.
3、 the seal of the oil seal and leakage of the response measures
1) master and identify the basic knowledge of shoddy products to buy high quality, standard oil seal.
2) If the outer surface roughness of the journal is low or rust, rust, burr and other defects to use fine sand or linoleum polished smooth; in the oil seal lip or journal corresponding to the location of cleaning oil or grease. Oil seal on the outer ring coated with a hard paper to the shaft of the keyway part of the package to avoid scratching the oil seal with a special tool to the oil seal in the rotation into the pressure can not be hard to hit the hard to prevent the oil seal deformation or squeeze the spring Failure; if there is lip flanging, spring off and oil seal skew must be removed when the reload. It should be noted that when the journal is not worn and the oil seal spring is sufficient, do not tighten the inner spring.
3) Application of the mechanical seal on the mechanical conditions of the general working conditions harsh environmental temperature difference between the dust and more frequent vibration of the mechanical parts of the mechanical conditions continue to change, so to check, maintenance and ground maintenance.
4) If the journal and bearings wear serious, oil seal rubber aging or spring failure should be timely repair and replacement of the corresponding parts.
5) on the abnormal heat of the parts or assembly should be promptly lifted to avoid mechanical overspeed, overload operation to prevent the oil seal lip temperature rise rubber aging lip early wear.
6) to always check the oil level If the oil impurities too much alloy powder, metal iron scraps to completely replace the new oil replacement oil grades and quality to meet the requirements of the season.
7) Temporarily unused oil seal should be kept in good condition to prevent contamination with oil, dust or sun exposure.
8) When the journal wear into a "V" -shaped groove so that the new oil seal lip contact with the pressure drop can not play the role of sealing oil can be used AR-5 two-component adhesive adhesive that is simple and reliable and wear can also be used Oil seal shift method to make up.