There is a thin viscous oil film between the oil seal lip and the shaft contact surface. The presence of this oil film not only seals the fluid medium, but also lubricates the lips and shaft. However, during the use of oil seals, due to the effect of the oil seal lip, differences in axial, rotational, and fluid sealing performance, as well as their interactions and coordination conditions, oil seals are often in a dynamic state of alternating fluid lubrication, boundary lubrication, and dry friction lubrication, with fluid lubrication being the main mode. Therefore, by ensuring that the oil film thickness is within an appropriate range, good sealing can be achieved.

Oil seal skeleton, which is the sealing of lubricating oil. Commonly used bearings for various machines, especially rolling bearings. Its function is to isolate the oil chamber from the outside, seal the oil inside, and prevent dust outside. The difference between oil seals and other lip seals is that they have a lip with greater elasticity, a narrow sealing contact surface width (about 0.5mm), and a sharp distribution pattern of contact stress. Typical structure of oil seal and schematic diagram of lip contact stress. The cross-sectional shape of the oil seal and the clamping spring provide better follow-up compensation for the lip to the shaft. So oil seals can achieve better sealing with less lip force.

 

Compared with other sealing devices, oil seals have the following advantages: ① simple structure and easy manufacturing. Simple oil seals can be molded in one go, and even the most complex oil seal manufacturing process is not complicated. Metal skeleton oil seals only need to be stamped, glued, embedded, and formed to form the desired oil seal from metal and rubber Lightweight and requires minimal consumables. Each oil seal is composed of thin-walled metal parts and rubber parts, with minimal material consumption, so the weight of each oil seal is very light The installation position of the oil seal is small, the axial dimension is small, the processing is easy, and the machine is compact Good sealing performance and long service life. Has certain adaptability to machine vibration and spindle eccentricity Easy to disassemble and maintain. ⑥ cheapness.