On the classification of rolling bearings

The following is copied over; please, everyone in charge, add the following details: 1. Classification by the structural type of rolling bearings: (1) Bearings are classified according to the direction of the load they can withstand or their nominal contact angle, as follows: 1) Radial bearings – Rolling bearings that are primarily used to bear radial loads, with a nominal contact angle ranging from 0 to 45 degrees. Based on the nominal contact angle, they are further divided into: radial contact bearings – centrifugal bearings with a nominal contact angle of 0; angular contact bearings – centrifugal bearings with a nominal contact angle ranging from greater than 0 to 45 degrees. 2) Thrust bearings——Rolling bearings primarily used to bear axial loads, with a nominal contact angle of more than 45 to 90 degrees. Based on the nominal contact angle, they are further divided into: axial contact bearings – thrust bearings with a nominal contact angle of 90 degrees; angular contact thrust bearings – thrust bearings with a nominal contact angle greater than 45 but less than 90 degrees. (2) Bearings are classified according to the type of their rolling elements as follows: 1) Ball bearings——with rolling elements that are balls; 2) Roller bearings——with rolling elements that are rollers. Roller bearings can be further classified according to the type of rollers as follows: Cylindrical roller bearings – these are bearings whose rolling elements are cylindrical rollers, with the length-to-diameter ratio of these cylindrical rollers being less than or equal to 3 ； Needle roller bearings – bearings whose rolling elements are needle rollers, with a length-to-diameter ratio of more than 3, but a diameter of 5 mm or less; Tapered roller bearings – bearings whose rolling elements are tapered rollers; Self-aligning roller bearings – bearings whose rolling elements are spherical rollers. (3) Bearings are classified according to their ability to self-align during operation as follows: 1) Self-aligning bearings – bearings whose raceways are spherical in shape, allowing them to accommodate angular deviations and angular movements between the axes of the two raceways ； 2) Non-self-aligning bearings (rigid bearings)----Bearings that can resist angular displacement of the axis lines between the raceways. (4) Bearings are classified according to the number of rows of rolling elements as follows: 1) Single-row bearings – bearings with one row of rolling elements; 2) Double-row bearings – bearings with two rows of rolling elements; 3) Multi-row bearings – bearings with more than two rows of rolling elements, such as three-row and four-row bearings. (5) Bearings are classified according to whether their components can be separated: 1) Separable bearings——Bearings with separable components ； 2) Indivisible bearings——Bearings in which the rings cannot be separated from each other at will after final assembly. (6) Bearings can also be classified into various structural types based on their shape and structure (such as the presence or absence of filling grooves, the presence of inner and outer rings as well as the shape of the rings, the structure of the flanges, and even the presence or absence of retainers). 2. Classification by rolling bearing size: Bearings are classified according to their outer diameter as follows: (1) Miniature bearings – bearings with a nominal outer diameter of 26 mm or less; (2) Small bearings – bearings with a nominal outer diameter ranging from 28 to 55 mm; (3) Medium-small bearings – bearings with a nominal outer diameter ranging from 60 to 115 mm; (4) Medium-large bearings – bearings with a nominal outer diameter ranging from 120 to 190 mm; (5) Large bearings – bearings with a nominal outer diameter ranging from 200 to 430 mm; (6) Extra-large bearings – bearings with a nominal outer diameter of 440 mm or more.

Bearing types can be identified from their codes. The composition of a bearing code is as follows: www.yr-jx.com. Prefix codes indicate the various components of the bearing; www.yr-jx.com. Basic codes represent the type and size of the bearing, among other key characteristics; www.yr-jx.com. Suffix codes denote the precision level and material properties of the bearing. The components of a bearing code are shown in the table below: Prefix code www.yr-jx.com, Basic code www.yr-jx.com, www.yr-jx.com, Suffix code www.yr-jx.com. Components of the bearing include codes for its internal structure, sealing and dust protection features, the support frame and its material, special bearing materials, tolerance grades, clearance values, multi-bearing arrangements, and other codes. Type code, size series code, inner diameter code, width series code, and diameter series code. For the inner diameter, it is generally calculated by multiplying the last two digits of the basic code by 5 to get the inner diameter in millimeters. For example, the inner diameter of bearing 6204 is 04×5=20 mm. www.yr-jx.com Common special cases: ㈠ When the inner diameter of the bearing is less than 20mm, www.yr-jx.com The inner diameter sizes in mm are 10, 12, 15, 17; the corresponding inner diameter codes are 00, 01, 02, 03. ㈡ When the inner diameter of the bearing is less than 10mm, the last digit of the basic code is used to represent the inner diameter size ； Example: For bearing 608Z, the last digit ‘8’ of the basic code ‘608’ is used as the inner diameter value; thus, the inner diameter of bearing 608Z is 8 mm. By the same logic, the inner diameter of 627 is 7 mm, and that of 634 is 4 mm. www.yr-jx.com ㈢ If the inner diameter of the bearing is not a multiple of 5 or is greater than or equal to 500 mm, the inner diameter codes are separated by a slash ‘/’. Another case: in some old codes for needle roller bearings, the inner diameter codes are separated directly by a ‘/’. In these cases, the numbers following ‘/’ represent the inner diameter of the bearing. See the examples below: www.yr-jx.com Bearing model: www.yr-jx.com 619/1.5 62/22 60/500 3519/1120 7943/25 Inner diameter size (mm): www.yr-jx.com 1.5 22 500 1120 25 These are some common ways of indicating the inner diameter of bearings; some companies around the world use different codes ； It should be based on the actual situation. Specifically, it is necessary to refer to various materials and sample products from different manufacturers. www.yr-jx.com Dimension series codes: Used to denote bearings with the same inner diameter but different outer diameters and widths, as shown in the figure. www.yr-jx.com: Diameter code ↑ ↑ www.yr-jx.com→→Width code. www.yr-jx.com: Outer diameter series codes: Extra light (0,1), Light (2), Medium (3), Heavy (4). www.yr-jx.com: Width series codes: The normal width is “0”; it is usually not indicated. However, for types such as tapered roller bearings (category 7) and self-aligning roller bearings (category 3), the “0” cannot be omitted. 6010 belongs to the lightweight series and is used for light loads and high speeds ； 6210 is part of the lightweight series; it has the most optimal speed for light loads, and it is the type with the widest range of applications ； 6310 is part of the medium-heavy series ； 6410 is a heavy-duty series, used for heavy loads at low speeds. Medium and heavy-duty types are the most widely used; they are found in various mechanical components, small and medium-sized electric motors, conveyor belts on assembly lines, motorcycles, and almost all other types of mechanical equipment. www.yr-jx.com Type codes: Remember the common bearing code categories: 3, 5, 6, 7, N; these correspond to the old code categories of 7, 8, 0, 6, 2 respectively. For www.yr-jx.com, the code for tolerance grades is shown in the table below: Centrifugal bearings and angular contact ball bearings are classified into five grades, from highest to lowest, as indicated in the table. New grade codes: www.yr-jx.com P2, P4, P5, P6, P0; Old grade codes: www.yr-jx.com B, C, D, E, G. Tapered roller bearings are classified into four grades, from highest to lowest, as shown in the table below. New grade codes: www.yr-jx.com P4, P5, P6x, P0; Old grade codes: www.yr-jx.com C, D, Ex, G(E). Thrust ball bearings are also classified into four grades, from highest to lowest. New grade codes: www.yr-jx.com P4, P5, P6, P0; Old grade codes: C, D, E, G. There are many examples available on this website. Deep groove ball bearings are mainly used in applications that experience high radial loads.