Discussion on the life index and rationality of seals2018-11-16
Due to defects in the sealing material, uncertainties in processing and use, there is no guarantee that the service life of each seal will be consistent. Second, we need to understand the test method for seal life. The life test is a destructive test, the service life is measured, and the seal is scrapped. Therefore, in the conventional case, the life of the seal is measured by sampling. In a large number of materials, a small amount of samples are taken from the seals with the same processing conditions for testing, and the life of the seals is estimated based on the test results.
To understand the rationality of the life of the seal, it is also necessary to understand the meaning of the life indicator of the seal. The life indicator is a probabilistic indicator, such as the most used mechanical oil seal in a car, and its life is based on the integrity rate. Taking 1000 mechanical oil seals as samples for life test, there may be the following situation: 1 mechanical oil seal is damaged when running 100 hours, 2 mechanical oil seals are damaged when running 100,000 hours, 5 mechanical oil seals are damaged when running 150,000 hours, running 1000000 When there were 10 mechanical oil seals damaged as a child, the rated life was 150,000 hours with a 95% good condition and 1000000 hours with a 90% perfect condition. In other words, your car is equipped with a mechanical oil seal seal with a rated life of 1,000,000 hours. It is also in accordance with the probability index when it is destroyed for 100 hours.