NSK skeleton of oil seal structure and sealing principle

Skeleton oil seal is simple, general has three parts: the oil seal body, strengthen skeleton and the tight spiral spring. FAG bearing seal according to different body parts and into the bottom, waist, the blade and the sealing lip, etc. Usually, in the free state of the skeleton oil seal, its inner diameter turn-on than small, which has certain “over surplus quantity”? Therefore, when oil seal into oil seal seat and shaft after, oil seal the blade pressure and the tight spiral spring contraction of axial force produce certain radial tight force, after a period of time operation, the pressure will quickly reduce and even disappear, therefore, plus spring can at any time compensation from the tight seal the force.

Sealing principle: SKF bearing in oil seal and axis due to exist the control of oil film oil, the oil film with fluid lubrication characteristics. In the liquid surface tension, under the action of oil film just make oil film rigidity contact with air end forms a new moon surface to prevent the leakage of medium, so as to realize the axis of the seal. Oil seal sealing ability, depending on the thickness of the sealing surface oil film, thickness is too large, oil seal leakage; Thickness is too small, possible dry friction, cause oil seal and axis wear; The sealing lip and no oil film between shaft, the easy cause fever, wear.

Therefore, at the time of installation must besmear on some oil in sealing ring, INA bearing and ensure skeleton oil seal and axis vertical line, if not vertical, oil seal sealing lip of the oil from vista shaft dry, also can cause the sealing lip excessive wear. In operation, the casing of the lubricant slightly a little, in order to achieve the sealing surface of the oil film formation in place of the state is most ideal.