Basic structure of bearing: inner ring, outer ring, rolling element and cage

Outer ring

The bearing ring is an annular part of a radial rolling bearing with one or several raceways.

Type of outer ring:

Tapered outer ring (tapered roller bearing)

Double raceway conical outer ring (double row tapered roller bearing)

Self aligning outer ring (self-aligning ball bearing, self-aligning roller bearing)

Outer spherical outer ring (outer spherical bearing)

Inner ring

Inner ring type:

Tapered inner ring (tapered bore bearing, such as self-aligning ball bearing, self-aligning roller bearing, outer spherical bearing)

Double raceway inner ring (double row ball bearing, double row roller bearing, double row tapered roller bearing)

Wide inner ring (outer spherical bearing)

Inner ring with flange (cylindrical roller bearing)

Rolling element

Rolling element is the core component of rolling bearing. Due to its existence, there is rolling friction between relative moving surfaces.

The types of rolling elements include ball, cylindrical roller, tapered roller, needle roller, etc

Bearings are divided into:

(1) Ball bearing - the rolling element is a ball, such as deep groove ball bearing, self-aligning ball bearing, angular contact ball bearing and outer spherical bearing

(2) Cylindrical roller bearing - the rolling element is cylindrical roller, such as cylindrical roller bearing, cylindrical roller bearing, roller bearing and tandem bearing

(3) Drum roller bearing - the rolling element is drum roller, such as self-aligning roller bearing

(4) Tapered roller bearing -- the rolling element is tapered roller, such as tapered roller bearing and thrust tapered roller bearing

(5) Needle roller bearing - the rolling element is a needle roller. The ratio of the length to the diameter of the needle roller is greater than 3, but the diameter is less than or equal to 5mm.

4. Cage

Bearing cage refers to the bearing parts that partially wrap all or part of the rolling element and move with it. It is used to isolate the rolling element and usually guide the rolling element and keep it in the bearing.

Main purpose of cage:

The heat generated by the rolling element of the bearing is reduced by friction

The rolling elements are evenly spaced to optimize the load distribution

Guide the rolling element in the no-load area of the bearing

For separate bearings, the rolling element can be kept as a whole when installing or removing one of the bearing rings

The main types of cages are:

Stamped metal cage

Stamped metal cages (steel or brass sheet) are lightweight and can withstand high temperatures.

Machine cut metal cage

The machined metal cage is made of brass, steel or light alloy. It can withstand high speed, high temperature, high acceleration and high vibration.

Polymer cage

Made of polyamide, ether ketone or other polymeric materials. Polymer material cages have good sliding properties and almost no friction, so they can allow high speed. In case of poor lubrication, these cages can reduce the risk of sudden failure and side effects of failure, because they can work under limited lubrication conditions for a period of time.

Strut type cage

Steel strut type cage is a pin through roller with perforation, and is only used for large-size roller bearings. This cage is relatively light and can accommodate a large number of rollers.

5. Bearing seal

Sealing can significantly extend the service life of the bearing because it retains lubricant in the bearing and keeps contaminants out.

Dust cover

There is a small gap between the dust cover and the inner ring. Bearings with dust covers are suitable for relatively clean conditions or applications where low friction is necessary due to speed or operating temperature. The dust cover is usually stamped from thin metal plate, fixed on one ring or washer of the bearing and extends towards another ring or washer, but does not contact with another ring or washer. It is a non-contact seal. The letter codes are ZZ, 2Z, ZZ and 2Zr

Sealing element

Bearings with seals are preferred for moderate contamination configurations. Where moisture and moisture cannot be removed, contact seals are usually used. These seals make active contact with the sliding surface of one of the bearing rings.

Letter code: 2RZ, 2RS, 2rs1, 2rsr, VV, DDU