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FAX: +86-574-62501118
E-mail: sales@nbkbearings.com

Technology

Technology ProcessTechnology Proces-01Technology Process-02Technology Process-03 Technology Process-04Technology Process-05
Bearing Clearance
The radial paly of NBK bearings might be divided into five groups according to ISO standard.
Borediameterd(mm) C2 C0 C3 C4 C5
Overt To Min Max Min Max Min Max Min Max Min Max
2.5 6 0 7 2 13 8 23 14 29 20 37
6 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

Shield,seal and lubrication
The structure of bearings consists of open and close types,and the close type might be equipped with shield sing or both sides(z,z);with non-contact seal on single single or both sides (L, 2L ),and with contact seal on single side or both sides (RS,2RS).
Our bearings are alreaby filled with proper oil grease, whitch can be used directly without any wash .They are fit for low or middle load,and low or middle speed.The work temperature is -20•C ~+ 110 •C .lf the conditions. Change,please connect with our engineers.
Bearing collarand ball materidl
The best material for bearing is high carbon chromium bearing steel,which has hardness,strong rolling fatigue resistance,wearing resistance and stable dimension.lts chemical composition is:
(wt%) C 0.9-1.05 Cr 1.40-1.63 Si 0.15-0.35 Mn 0.25-0.45 P 0.027 P = 0.02
(wt%) Ni <0.23 Cu = 0.25 Mo = 0.1 Sn <0.03 As <0.04 As <0.005
(wt%) Sb <0.002 Pb <0.002 O <0.001 Al <0.05 Ca <0.01  

Technology Process-06
Beraing accuracy
Bearing accuracy refers to accuracy on dimension and rotation. According to national standard, the bearing accuracy is divided into five classes:Classes 0,Classes 6,Classes 5,Classes 4,Class 2.AII of them are equivalent to ISO standard.The Comparison of different accuracy classes are shown as follows:
Inner ring
Bore Diameterd(mm) over to Dmp Bore Tolereance limits Kia Radial Runout SD Side Runout with bore Sia Axis Runout Bs Width limits Vbs Width Variation
Class0 Class6 Class5 Class4 Class2 Class0 Class6 Class5 Class4 Class2 Max Class5 Class4 Class2 Max Class5 Class4 Class2 Max Class0 Class6 Class5 Class4 Class2 Class0 Class6 Class5 Class4 Class2 Max
2.5 10 10 18 18 30 30 50 0 -8 0-7 0-5 0-4 0-2.5 0 -8 0-7 0-5 0-4 0-2.5 0 -10 0-8 0-6 0-5 0-2.5 0 -12 0-10 0-8 0-4 0-2.5   •  6 4 2.5 1.5 •  7 4 2.5 1.5 •  8 4 3 2.5 15 10 5 4 2.5 7 3 1.5 7 3 1.5 8 4 1.5 8 4 1.5 7 3 1.5 7 3 1.5 8 4 2.5 8 4 2.5 0 -120 0 -40 0 -40 0 -120 0 -80 0 -80 0 -120 0 -120 0 -120 0 -120 0 -120 0 -120 15 15 5 2.5 1.5 20 20 5 2.5 1.5 20 20 5 2.5 1.5 20 20 5 3 1.5
Outer ring
Out Diameter D(mm) Dmp Bore Tolerance limits Kea Radia1Runout Max SD Side Runout with bore Max Sea Axis Runout Max Cs Width limits Vcs Width Variaton Max
Class0 Class6 Class5 Class4 Class2 Class0 Class6 Ckass5 Class4 Class2 Class5 Class4 Class2 Class5 Class4 Class2 Class0 Class6 Class5 Class4 Class2 Class0 Class6 Class5 Class4 Class2
6 18 18 30 30 50 50 80 80 120 0 -8 0 -7 0 -5 0 -4 0 -2.5 0 -9 0 -8 0 -6 0 -5 0 -4 0 -11 0 -9 0 -7 0 -6 0 -4 0 -13 0 -11 0 -9 0 -7 0 -4 0 -15 0 -13 0 -10 0 -8 0 -5 15 8 5 3 1.5 15 9 6 4 2.5 20 10 7 5 2.5 25 13 8 5 4 35 18 10 6 3 8 4 1.5 8 4 1.5 8 4 1.5 8 4 1.5 9 5 2.5 8 5 1.5 8 5 1.5 8 5 2.5 10 5 4 11 6 5 Same as the matched inner ring 5 2.5 1.5 5 2.5 1.5 Same 5 2.5 1.5 as the 6 3 1.5 Matched 8 4 2 inner ring