1. According to the structural types of rolling bearings, (1) bearings can be divided into: 1) centripetal bearings, which are mainly used to bear radial loads, with nominal contact angles ranging from 0 to 45. According to the different nominal contact angle, it can be divided into radial contact bearing - radial contact bearing with nominal contact angle of 0: centripetal contact bearing - radial bearing with nominal contact angle greater than 0 to 45. 2) Thrust bearing -- mainly used to bear axial load rolling bearing, its nominal contact angle is more than 45 to 90. According to the different nominal contact angle, it can be divided into axial contact bearing -- thrust bearing with nominal contact angle of 90; thrust angle contact bearing -- thrust bearing with nominal contact angle greater than 45 but less than 90.
2. According to the types of rolling element, bearings are divided into: 1) ball bearing -- rolling element is ball; 2) roller bearing -- rolling element is roller. According to the types of rollers, roller bearings are divided into: cylindrical roller bearing -- the rolling element is the bearing of cylindrical roller, the ratio of length to diameter of cylindrical roller is less than or equal to 3; needle roller bearing -- rolling element is needle bearing, the ratio of needle length to diameter is greater than 3, but the diameter is less than or equal to 5mm; tapered roller bearing -- rolling element is tapered roller bearing; Self aligning roller bearing -- the rolling element is a spherical roller bearing. (3) Bearings can be divided into: 1) self aligning bearings -- bearings with spherical raceways, which can adapt to angular deviation and angular motion between two raceway axes; 2) non self aligning bearings (rigid bearings) -- bearings that can resist the angular deviation between raceways.
3. According to the rolling bearing size classification, the bearing according to its outer diameter size size, can be divided into: (1) micro bearing - bearing with nominal outer diameter less than 26mm; (2) small bearing - bearing with nominal outer diameter size range of 28-55mm; (3) medium and small bearing - bearing with nominal outer diameter size range of 60-115mm; (4) medium and large bearing - bearing with nominal outer diameter size range of 120-190mm (5) Large bearing -- bearing with nominal outer diameter of 200-430mm; (6) extra large bearing -- bearing with nominal outer diameter of 440mm or more.