Page 66 - NSK_CAT_E1102m_A7-141

TECHNICAL DATA

15.5 Coefficients of Dynamic Friction and (3) Radial Internal Clearance & r and Fatigue Life L Table 15. 7 ε and f (ε), Lε/L
Other Bearing Data (Fig. 15.13)
Deep Groove Ball Bearings Cylindrical Roller Bearings
(1) Bearing Types and Their Coefficients of Dynamic For the radial internal clearance & r and the function f
ε f (ε) L⎯Lε f (ε) L⎯Lε
Friction μ (ε) of the load factor, the following equations are valid:
For Deep Groove Ball Bearings 0.1
μ= M 0.2 33.713 0.294 51.315 0.220
d 1 0.3 10.221 0.546 14.500 0.469
0.737 0.691
P⋅ 2 f (ε) = & r ⋅ Dw 3 ....................................(N) 0.4 4.045 5.539
0.5
( )0.00044 Fr 2 0.6 1.408 0.889 1.887 0.870
3 0 1.0 0 1.0
Z 0.7 − 0.859 1.069 − 1.133 1.075
Table 15.5 Coefficients of Dynamic Friction 0.8
1 0.9

Bearing Types Approximate values of μ f (ε) = & r ⋅ Dw 3 ....................................{kgf }2 1.0 − 1.438 1.098 − 1.897 1.096
( )0.002 Fr 3 1.25 − 1.862 1.094 − 2.455 1.065
Deep Groove Ball Bearings 0.0013 1.5 − 2.195 1.041 − 2.929 0.968
Angular Contact Ball Bearings 0.0015
Self-Aligning Ball Bearings 0.0010 Z 1.67 − 2.489 0.948 − 3.453 0.805
Thrust Ball Bearings 0.0011 1.8 − 3.207 0.605 − 4.934 0.378
For Cylindrical Roller Bearings 2.0 − 3.877 0.371 − 6.387 0.196

Cylindrical Roller Bearings 0.0010 f (ε) = & r ⋅ L 0.8 ..................................(N) 2.5 − 4.283 0.276 − 7.335 0.133
Tapered Roller Bearings 0.0022 we 3 − 4.596 0.221 − 8.082 0.100
Spherical Roller Bearings 0.0028 4 − 5.052 0.159 − 9.187 0.067
( )0.000077 Fr 0.9
Z 5 − 6.114 0.078 −11.904 0.029
10 − 7.092 0.043 −14.570 0.015
Needle Roller Bearings (ε) &r ⋅ L 0.8 − 8.874 0.017 −19.721 0.005
with Cages 0.0006 we
0.0015 ( )f = . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .{kgf } −10.489 0.008 −24.903 0.002
Full Complement Needle 0.0025 Fr 0.9 −17.148 0.001 −48.395 0.0002
Roller Bearings 0.0028
Z
Spherical Thrust Roller
Bearings The relation between the load factor ε and f (ε) and

Lε / L , when the radial internal clearance is & r is as
shown in Table 15.7.

From the above equations, first obtain f (ε) and then ε

and Lε / L can be obtained.

(2) Circumferential Speeds of Rolling Elements
about Their Centers and Bearing Center

Table 15.6 Circumferential Speeds of Rolling Elements about Lε 1.0
Their Centers and Bearing Center L
P=Cr/5 6208
P=Cr/10 Cr=29 100 N
0.8 P=Cr/15

Items Rotating inner ring, fixed outer ring Rotating outer ring, fixed inner ring Life Ratio 0.6

Ball rotating speed ( )− Dpw − cos2α ni ( )+ Dpw − cos2α ne
Dw Dpw/Dw 2 Dw Dpw/Dw 2
na (min–1)

0.4

Cicumferential ( )− π ⋅ Dw Dpw − cos2α ni ( )+ π ⋅ Dw Dpw − cos2α ne 0.2 NU208 P=Cr/5
speed around 60 × 103 Dw Dpw/Dw 2 60 × 103 Dw Dpw/Dw 2 Cr=43 500 N P=Cr/10
bearing ball's center
P=Cr/15
υa (m/sec)

Revolving ( )+ 1− cos α ni ( )+ 1− cos α ne −60 −40 −20 0 20 40 60 80 100 120
speed around Dpw/Dw Dpw/Dw
bearing center 2 2

nc (min–1) Radial Internal Clearance & r μm

Cicumferential ( )− π ⋅ Dpw ni ( )+ π ⋅ Dpw ne
speed around 60 × 103 60 × 103
bearing center 1− cos α 2 1− cos α 2 Fig. 15.13 Radial Internal Clearance and Life Ratio

υc (m/sec) Dpw/Dw Dpw/Dw

Remarks 1. + sign indicates CW rotation and − sign CCW
Remarks 2. The revolving speed and circumferential speed of the rolling elements are the same as those of the

cage.

A 136 A 137