Q: How to calculate bearing outer diameter?

Common special cases:

When the bearing inner diameter is less than 20mm

Bearing inner diameter is (mm)

10

12

15

17

The corresponding inner diameter code is

00

01

02

03

2. When the inner diameter of the bearing is less than 10mm, directly use the last digit of the basic code to indicate the size of the inner diameter of the bearing; for example: for the bearing 608Z, use the last digit 8 of the basic code ‘608’ as the inner diameter. The inner diameter of the bearing 608Z is 8mm. By analogy, the inner diameter of 627 is 7mm, and the inner diameter of 634 is 4mm.

3. The inner diameter of the bearing is not a multiple of 5 or greater than or equal to 500mm. The inner diameter code is separated by a slash '/'. In another case: some old needle bearing inner diameter codes are directly separated by '/'. In these cases, the number of digits behind the '/' is the bearing inner diameter. See the example below:

Bearing Type

619 / 1.5

62/22

60/500

3519/1120

7943/25

Inner diameter size (mm)

1.5

twenty-two

500

1120

25

The above are several common methods of bearing inner diameter. Some companies in the world have different codes; the actual situation shall prevail. Specific reference to various materials and manufacturers' samples.

Size series code: It is used to express bearings with the same inner diameter but different outer diameters and widths, see figure.

Outer diameter series code: Extra light (0,1), light (2), medium (3), heavy (4)

Width series code: Generally the normal width is "0", which is usually not marked. However, "0" cannot be omitted for tapered roller bearings (type 7) and spherical roller bearings (type 3).

Deep groove ball bearing 6010 is a light and thin series, which is used for light loads and high speeds; 6210 is a light series, which has the most reasonable speed for light loads and the most widely used type; 6310 is a medium and heavy series; 6410 is a heavy series for heavy loads and low speeds. Medium and heavy-duty applications are the most widely used, such as various types of mechanical transmission parts, small and medium-sized motors, assembly line conveyors, motorcycles, and other various machinery and equipment. These two types are almost used.

Type code: Remember the commonly used bearing code: 3,5,6,7, N five types, corresponding to the old code is 7,8,0,6,2. For details, please refer to the product classification on the homepage of this site.

See the table of tolerance grade codes:

Radial bearings and angular contact ball bearings are divided into five levels as shown in the table below (high → low)

P2

P4

P5

P6

P0

Old rank code

B

C

D

E

G

Tapered roller bearings are divided into four levels as shown in the table below (high → low)

P4

P5

P6x

P0

Old rank code

C

D

Ex

G (E)

Thrust ball bearings are divided into four levels as shown in the table below (high → low)

P4 P5 P6 P0

Old rank code

C D E G

If a higher tolerance level bearing is required, a suitable tolerance level bearing can be selected according to the GB307 standard.

Clearance code: The clearance code is divided into six levels with / C1 / C2 / C3 / C4 / CM as the code, CM is the bearing clearance group for the motor, and the larger the value of other clearance groups, the larger the clearance; C0 is the basic group The clearance is not marked. When selecting the bearing clearance, full consideration must be given to the bearing mounting hole and the tolerance and temperature of the bearing and the shaft. For details, please refer to the GB / T4604 standard or consult this site.

Example code method:

Example ① 6308 6--Deep groove ball bearings, 3--medium series, 08--inner diameter d = 40mm, tolerance class "O", clearance group is "0" group are not marked;

Example ② N105 / P5 N--Cylinder roller bearing, 1--Extra light series, 05--Inner diameter d = 20mm, Tolerance class is 5th grade, Clearance group is “0” Group is not marked;

Example ③7214C / P4 7--Angular contact ball bearings, 2--light series, 14--inner diameter d = 70mm, C--nominal contact angle α = 15 °, P4--tolerance level is 4th, clearance group is "0" group;

Example ④ 30213 3--tapered roller bearing, 0--normal width (0 cannot be omitted), 2--light series, 13--inner diameter d = 65mm, tolerance class is 0, clearance group is "0" group;