Roller bearings are widely used on various kinds of the fundamental element of machinery. Roller bearings are consists of inner ring, outer ring, rollers, and cage. Normally inner ring is used to assemble on the shaft and rotate with shaft. Outer ring is used to assemble in bearing housing or machinery housing to support. In some application there is also outer ring rotates, but inner ring fixed or both inner ring and outer ring rotate.

Types of roller bearings

1.According to the bearing structures

(1)According to the rolling element type

1)Ball bearings—the rolling element is ball
2) Roller bearings—the rolling element is roller
2-1) Cylindrical roller bearings—rolling element is cylindrical roller, the ratio of the length to diameter of the cylindrical roller is less than or equal to 3.
2-2) Needle roller bearings—rolling element is needle roller the ratio of the length to diameter of the needle roller is larger than 3 with diameter less or equal 5mm
3) Tapered roller bearings—rolling element is tapered roller
4) Self-aligning roller bearings—rolling element is spherical roller

(2)According to the direction of bearing capacity

1)Radical bearing—Mainly adapt to the radical capacity the angle contact from 0°-45° . By different angles they are divided in to following:
1-1)Radical contact bearings—nominal contact angle is 0°
1-2)Centripetal bearings—nominal contact angle is larger than 0°but less than 45°
2)Thrust bearings—Mainly adapt to the axial load capacity. By different angle among 45°-90°, they are divided into following:
2-1)Axial contact bearings—nominal contact angle is 90° thrust bearing
2-2)Thrust angle contact bearings—nominal contact angle is larger than 45°but less than 90°

(3).According to the rows of roller

1)Single row bearing—there is only one row roller of the bearing
2)Double rows bearing—there are two rows roller of the bearing
3)Multi-rows bearing—there are more than two rows of the bearing, like three rows roller of bearing or four rows roller of bearing

(4).According to the bearing can be separate or not

1)Separate bearing—there is part to separate of the bearing
2)Non-separate bearing— Rings can’t separate after assembling final.

2.According to bearing sizes

(1)Miniature bearings—Outer ring diameter is less than 26mm
(2)Small bearings—Outer diameter is among 28-55mm
(3)Medium and small size bearings—Outer diameter is among 60mm-115mm
(4)Medium and large size bearings—Outer diameter is among 120-190mm
(5)Large size bearings—Outer diameter is among 200-430mm
(6)Especially large size bearings—Outer diameter is larger than 440mm