Bearing Knowledge

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On 2020-08-12

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Bearing knowledge include bearing inner diamater calculation, bearing precision and internal clearance.

Bearing Inner Diameter：

ID（mm）	ID Code（mm）	For Example
10	0	6201 Bearing, 01 stands for bearing ID is 12mm
12	1
15	2
17	3
20~480	Bearing ID= ID Code*5	6205 Bearing , 05 standars for bearing ID is 25mm

Bearing Knowledge- Bearing Precision：

Bearing precision, in other words dimensional accuracy and rotation accuracy, has corresponding international standards and national standards.
National standards for different countries are consistent with international standard.

Country	Standard	Precision
China	GB/T307.1	P0	P6	P5	P4	P2
USA	ANSI/AFBMA Std.20	ABEC-1	ABEC-3	ABEC-5	ABEC-7	ABEC-9
Japan	JIS B 1514	0	6	5	4	2
Germany	DIN 620	P0	P6	P5	P4	P2
International	ISO 492	Class 0	Class 6	Class5	Class4	Class2

Internal Clearance:

Internal bearing clearance refers to the amount of radial or axial displacement when either the inner ring or the outer ring is fixed, and the unfixed one is moved. Depending on the direction of movement, it can be divided into radial clearance and axial clearance.
Generally we control the radial clearance for deep groove ball bearings , while we control axial clearance for double row angular contact ball bearings.

For deep groove ball bearings, radial clearance is as below,

Bearing ID(mm)		C2		C0		C3		C4		C5
＞	≤	min	max	min	max	min	max	min	max	min	max
2.5	10	0	7	2	13	8	23	14	29	20	37
10	18	0	9	3	18	11	25	18	33	25	45
18	24	0	10	5	20	13	28	20	36	28	48
24	30	1	11	5	20	13	28	23	41	30	53
30	40	1	11	6	20	15	33	28	46	40	64
40	50	1	11	6	23	18	36	30	51	45	73
50	65	1	15	8	28	23	43	38	61	55	90
65	80	1	15	10	30	25	51	46	71	65	105
80	100	1	18	12	36	30	58	53	84	75	120

For double row angular contact ball bearings, axial clearance is as below,

Bearing ID (mm)		C2		C0		C3
＞	≤	min	max	min	max	min	max
—	10	1	11	5	21	12	28
10	18	1	12	6	23	13	31
18	24	2	14	7	25	16	24
24	30	2	15	8	27	18	37
30	40	2	16	8	29	21	40
40	50	2	18	11	33	23	44
50	65	3	22	13	36	26	48
65	80	3	24	15	40	30	54
80	100	3	26	18	46	35	63

If you have any questions or suggestion about the bearing knowledge that we shared, just leave a comment and we will give you reply within 12 hours !

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