The self-contained seal is mainly a contact seal design. Because the seal is in direct contact with the shaft, friction and wear are severe during operation, so it is only suitable for low-speed places. Contact seals mainly include felt seals and lip seals. The felt ring seal is to open a trapezoidal groove on the deep groove ball bearing cover, make the felt into a ring or belt row according to the specification, and place it in the trapezoidal groove to make close contact with the shaft.
The felt ring seal is mainly used in grease-smooth places. The structure is simple, but the friction coefficient is large. It is only used in the center where the sliding speed is less than 4-5m/s and the working temperature is not higher than 90°C. The lip seal is to place a lip seal made of oil-resistant rubber in the deep groove ball bearing cover, which is tightly sleeved on the shaft by the elastic force of the bent rubber and the clasping action of the additional annular coil spring, to play a sealing role.
The direction of the sealing lip of the lip seal should be towards the sealing part. That is, the sealing lip should face the deep groove ball bearing (inward), assuming that it is primarily for oil sealing. Assuming that the main purpose is to avoid foreign intrusion, the sealing lip should face away from the deep groove ball bearing. Assuming that both requirements are required, it is to use two lip seals with the sealing lips placed in opposite directions. The lip seal can be used in places where the sliding speed of the contact surface is less than 10m/s or less than 15m/s.
Professional technical dry goods, the introduction of deep groove ball bearing sealing method, external seal, and external seal mainly adopt the design of labyrinth type and contact type. The more stages of the labyrinth (not lower than the two poles), the smaller the gap, the better the sealing effect. The clearance of the labyrinth is 0.6~1.5mm on one side in the radial direction and 4~6mm in the axial direction according to the size of the deep groove ball bearing. The contact-type skeleton oil seal is widely used in rolling mills, and to increase the effect, two or three can be used in parallel.
