What is the working principle of the bearing oil seal?

1. In the free state, the inner diameter of the oil seal lip is smaller than the shaft diameter and has a certain amount of interference.
2. After installation, the interference pressure of the oil seal edge and the contraction force of the self-tightening spring will produce a certain radial pressure on the rotating shaft.
3. When working, the oil seal lip forms a sealing contact ring with a width of 0.25 to 0.5 mm under the action of radial pressure. Under the action of lubricating oil pressure, the oil penetrates into the oil seal cutting edge and the shaft to form a very thin oil film. The oil film formed by the internal friction of the lubricant at the contact point and the stirring and squeezing of the lubricant is affected by the surface tension of the oil, forming a "crescent" surface on the outer edge of the rotating shaft and the oil seal to prevent the oil from spilling and play a sealing role.