In everyday use, in order to maintain good bearing lubrication conditions and normal working environment, full performance of the bearing, prolong the service life of the bearings must have an appropriate seal. Seal prevents lubricant leakage and dust, moisture or other contaminants intrusion.
Overall, bearing the seal can be divided into two categories comes with seals and external sealing. According to the working conditions and working environment bearing seal degree requirements in engineering design often use a combination of sealed form, in order to achieve a better seal.
The so-called built-sealed bearing is to manufacture the bearing itself into a sealing performance of the device. Such as bearings with dust cover, ring. This seal is very small footprint, easy installation and removal, the cost is relatively low.
The so-called plus bearing sealing performance device that is installed inside the cover, such as sealing device manufactured with a variety of properties. Plus non-contact seal is divided into two kinds of contact. Are as follows:
1) non-contact seal
Non-contact seal is a seal relative thereto moving parts are not in contact, and there is adequate clearance seal. This form of the seal, at work almost no friction heat, no wear, especially for high-speed and high-temperature applications. Non-contact seal commonly various forms gap type, labyrinth and gasketed and other structures were used in different occasions.
Non-contact seal gap as small as possible is better.
2) contact seals
Contact seal is sealed relative thereto in contact with moving parts and no gap seal. This seal seals due to direct contact with the mating parts, a larger friction at work, the heat is also large, easily lead to poor lubrication, the contact surface is easy to wear, causing the sealing effect and performance. Therefore, it is only suitable for medium and low speed operating conditions. Contact seals common form felt seals, cup sealing structure, used in different occasions.
Bearing seals plus several choices should consider the following factors:
1. Bearing lubricant and type (greases and oils);
2. The bearing of the working environment and the size of the space;
3. The advantage of the support structure axis, allowing angular deviation;
4. The peripheral speed of the sealing surface;
5. Bearing operating temperature;
6. The manufacturing costs.