Bearing the seal can be divided into two categories comes with seals and external sealing. 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.

Bearing seals plus several choices should consider the following factors:

1. Bearing lubricant and type (grease and lubricants);

2. Bearing operating environment, the size of the space occupied;

3. Advantages shaft support structure, allowing angular deviation;

4. The peripheral speed of the sealing surface;

5. Bearing operating temperature;

The manufacturing costs.

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.