18-10-2023

SELECTION OF ROLLING
ELEMENT BEARING FROM
MANUFACTURER CATALOGUE

RA

SELECTION PROCEDURE OF ROLLING CONTACT (Anti-Friction) Bearings :

The manual procedure for the selection of bearing from manufacture's catalogue
consists following steps;
1. Calculate radial and axial load acting on the bearing
2. Calculate the diameter of the shaft where bearing is to be fitted
3. Select the type of bearing for the given application
4. Select a suitable bearing type from manufacturer's catalogue based upon the
standard shaft diameter(start from the lowest series for the chosen bearing type).
5. Note the static load rating Co, Dynamic load rating Cand Life of bearing.
6. Calculate ratio eCo and find corresponding value of e
Fa
7. calculate the ratio of
VF
onthe basis of axial force F, and radial force F,.
where V= race rotation factor. Compare this value with design factor e.

1
 18-10.

R
. Whi
Y, the radial and thrust factors, from the
8. Now, determine the value of X and rac

the limiting value "e". to

catalogue, which depends upon the ratios , a and Co' VEr
9. Then calculating the equivalent dynamic load (FJ from the
equation,
F = (XVF, + YF)C,
Cg = Load application factor
10. Decide expected bearing life in million of revolution.
11. Then calculating C(dynamic load capacity) from the equation

or C= FLa
where,a = 3, for ballbearings,
10/3, for roller bearings.
12. Now, we check whether the bearing has the required dynamic capacity. If not,
selecting the bearing of the next series and go back to step (4).

Comparisonof Static Load Capacity and Dynamic load Capacity

The static capacity for deep-groove ball bearings commonly ranges from about half or less
of the basic dynamic load rating Cfor quite small bearings up to near equality for larger
bearings of the common series. For large roller thrust bearings, the static capacity may
range up to over twice the dynamic rating.
Table 13.11 Typical CoJC ratios of statie capacity to basie dynamic load raling
Angulur-contact Cylindrical
Deep-groove ball bearings ball bearings roller bcarings
Bearing
bore 19XX 01XX 02XX 03XX 72XX 73XX N2XX N3XX
serics series series serics Series series
(mm) Series scrics

0.34 0.36
7 0.36 0.42
0.38 0.42 0.46 0.42 0.48
0.51 0.51 0.48 0.47 0.54 0.52 0.82 0.79
0.57 ).53 0.52 0.49 0.59 0.55 0.88 0.84
20
30 0.63 0.62 0.57 0.57 0.66 0.61 0.96 0.94
0.6| 0.78 0.69 I.08 L.02
50 0.7| 0.74 0.66
0.82 0.74 0.65 0.84 0.76 1.18
70 0.77
0.98 0.89 0.75 ).81 0.90 0.94 1.21 1.26
L.00 0.95 L03 1.15 L21 1.24 L37
|50 L.05

2
 18-10-2023

18-10
ROLLING BEARING MATERIALS
" Whlle the contact surfaces of a bearing's Propertlesi
AISI 52100 Chromo Stoel Data Sheet

raceways and rolling elements are subjected Mardness 00-07 RC TO0.D00 HV

to repeated heavy stress, they still must Sllength.
maintaln high precislon and rotational ve srengi 203,000 pai
accuracy, To acCompllsh this, the raceways chemical Make Up %1
and rolling elements must be made of a rbonC To 99. 10 .
material that has high hardness, is resistant Çhromiun C!
Manganese Mn 025 % Max
to rolling fatigue, is wear resistant, and has on S
LPhosphot
) 15.0 .10 %
0 03Mav
g0od dimensional stability. The most o028 NM¡x

Common cause of fatigue in bearings 0s the speclficatlon1

inclusion of non-metallic impurities in the Epachcalon Equivalent $tandards
AISI 31200
steel. _Nonmetallic inclusion includes hard OIN100co
AFNT00C
oxides that can cause fatigue crack. Clean
steel with minimal non-metallic inclusion
BSSMA09
must therefore be used. JIS GJA05 SUJ2

Problem
A50 mm bore (02-series) deep-groove ballbearing, such as shown in Figure,
carries a combined load of 9kN radially and 6 kN axially at 1200rpm. Calculate
a. The equivalent radial load
b. The median life in hours
Assumptions:The inner ring rotates and the load is steady.

Solution:
Referring to Table, we find that, for a 50 mm bore bearing, C= 35.1 kN and Co = 19.6 kN.
To obtain the values of the radial load factors Xand Y
6 E, 6
=0.306, =0.667.
C 19.6 VE, 1(9)

3
 Dimensions and Basic Led Ratings tor 02-Series BallBearngs
Load Ratings (kN)
Deep Groove Angular Contact
OD, D. Width, u Fillet Radius, r
Bore, D (mm) (mm) (nm) (mm) C
507 224 494 212
3 10 7 02 305
0.6 7 SU 355 8.06 3.65
17 0.6 956 450 9 95 475
20 127 h 20 133 6.55
25 52 I0 140 65 765
l0 195 100 203
5 73 17 25,5 |37 270 150
I8 I0 07 |66 3|9 18.6
85 19 I0 112 I8 6 15.8 21.2
0 20 35 1 196 37.7 22 8
55
21 15 436 250 46 2 285
15 475 28 0 559 35 5
65
I5 555 34 0 63.7 41.5
70
125 15 175 64 9 455
28 405 715 490
20 702 450 55 0
20 832 530 04 63.0
20 95.6 62 0 106 73.5
170 20 108 695 121 850

Dimensions and Basic Load Ratings for Straight

Cylindrical Bearings
02-Series
03-Series
OD, D, Width, w Load Rating, C OD, D,
Bore, D (mm) (mm) (mm) (kN)
Width, w Load Rating,
(mm) (mm)
25 52
C(kN)
)5 16.8
30 62 17
62 28.6
22.4 72 19
35 36.9
31.9 80 21 44.6
18 41.8
45 90 23
85 19 56.1
44.0 100 25
90 20 72.1
45.7 110
55 27 88.0
100 21 56.1 120 2
60 110 22 102
64.4 130
65 31 123
120 23 76.5 140 33
70 125 24 138
79.2 150
75 35 151
130 25 91.3 160 37
80 140 26 183
106 170 39
85 150 28 190
119 180
90 160 30 212
142 190
95 43 242
170 32 165 200 45
264
Source. Bamberger, E.N. et al., Life Adjustment
Factors for Ball and Roller Bearings: An
Design Guide, New York, ASME, 1971. Engieering
Note: Bearing life capacities,C, for 10° revolution life with
kips, divide the given values by 4.448. 90% reliability. Toconvert from kN to

4 2
 18-10-2023

Factors for Deep-Croove Ball Bearings

FJC, X Y

0.014* 0.19 2.30

0.21 0.21 2.15
0.028 0.22 1.99
0.042 0.24 1.85
0.056 0.26 L.71
0.070 0.27 1.0 () ),56 163
0.084 0.28 1.55
0.110 0.30 1.45
0.17 0.34 1.31
0.28 0.38 1.15
0.42 0.42 1.04
0.56 0.44 1.00

Source: Based on Bamberger, E.N. et al., Life Adjustment Factors for Ball and Roller
Bearings: An Engineering Desigu Guide, New York, ASME, 1971.
a Use 0.014 if F,/C <0.014.

Factorsfor Commonly Used Angular-Contact Ball Bearings

Single-Row Bearing Double-Row Bearing
FJVE, > e F/VE, S EJVE,>

Contact Angle (a) X Y X Y X

0.38 0.015 1.47 1.65 2.34

0.40 0.029 1.40 1.57 2.28
0.43 0.058 1.30 146 2.1|
0.46 0.087 1.23 1.38 2.00
15° 0.47 ).12 0.44 1.19 1.0 134 0.72 1.93
0.50 0.17 1.12 1.26 1.82
0.55 ().29 L02 1.14 1.66
0.56 0,44 1.00 1.12 l.63
0.56 ).58 1.00 1.12 1.63
25 ().68 (0.4| 0 87 L0
35 0 95 (037 () 66 L0 () 60 107

Soure: Adapted from Bamberger, E.N. t al., Lte Adustmet lactos r Ball and Rolley
Beurings: AnEngierg DesgnGuide, New York, AS\ME, 1971.
Number of rows of balls.

5
 >e:X=0.56 andY= 1.13 by interpolation
We find from the table thata
VE

equivalent dynamic load Fe = (XVE, + YE)C,

(0.56)(1)(9) +(113)(6) =11.82 kN
F = V = 19) = 9 kN.
Since 11.95 >9 kN, the larger value is used for life calculation.
The rating life
L10
-) 11.82 ) =26.19(10*) rev
life in working hours is given by L= 60N Lh/10
106
Lh = Lx 60N = 364 h
The median life is therefore Lso = 5L10 =1820 h

Problem:Find the median Life of aDeep-Groove Ball Bearing under Moderate Shock if
outer ring rotates
We now have V = 1.2
Now

6 106
0.556 Ly =Lx = 35.5364 h
VE 1.2(9) 60N

Table shows that still Fa/VFr> e;

the median life is
therefore,X=0.56 and Y= 1.13, as
before
F = (XVF, + YF)C, Lso =5L0 = 177.5 h
= 2(0.56 x1.2 x9 +1.13 x6) = 25.66 kN

6
 18-10-2023

10

Problem: What change in the loading of a ball bearing willincrease the expected life
by 25%?

Solution :We know that

1/3
F, = F

F; = 0.928F

Shock or Service Factors K.

Type of Load Ball Bearing Roller Bearing
Constant or steady 1.0
Light shocks 1.5
Moderate shocks 2.0 1.3
Heavy shocks 2.5 1.7
Extrenne shocks 3.0 2.0

7
 Radial and Thrust Factors for Statically Loaded
Bearings
Bearing type Single row Double row
Xo Yo Yo
Radial dewp-groove ball 0,6 05 06 )5
Radial angular-contact ball B- 20 0.5 0.42 0.84
B25° 0.5 0.38 0.76
30 0.5 0.33 0.66
B 35° 0.5 0.29 0.58
B 40 0.5 0.26 1 0.52
Radial self-aligning ball 0.5 0.22 cot3 0.44 cot
Radial spherical roller 0.5 0.22 cot3 0.44 cot
Radial tapered roller 0.5 0.22 cot3 0 44 cot 6

Table 13.8: Radial factor X, and thrust factor Y, for statically stressed radial
bearings.

Problem: Agleaning-cylinder support shaft for aproposed "new concept" agricultural

combine has been stress-analyzed to find that the minimum required strength-based
shaft diameter is 1.60 inches at one of the proposed bearing sites. From the associated
force analysis and other design specifications, the following information has been
assembled:
1. Radial bearing load =370lb (steady).
2. Axial bearing load= 130lb (steady).
3. Shaft speed -350rpm.
4. Design life specification is 10 years of operation, 50days/year, 20 hr/day.
5. Design reliability specification is 95 percent.
6. The shaft is to be V-belt driven. Select a rolling element bearing for this application.

Example11.1 Collins
 Problem :A No. 207 radial-contact ball bearing supports ashaft that rotates 1000rpm.
A radial load varies in such a way that 50, 30, and 20 percent of the time the load is 3, 5,
and 7 kN, respectively. The loads are unifornm, so that Ka = 1. Estimate the
the median life of the B10 life and
bearing.

Problem:A single-row deep groove ball bearing is used to

specdaulomobile gear box. Il is subjected to the support the lay shatt of a four
The lay shaft is fixed to the engine shaft and following loads in respective speed ratios.
rotates at 1750 rpm. The static and dynamic load
carrying capacities of the bearings are 11600 and 17600 N respectively. The bearing is
Cxpected to be in use for 4000 hours of operation. Find out the
couldbe expected reliability with which the lite

Gear Axial Load(N) Radial Load (N) %time engaged

First Gear 3250 4000 1%
Second Gear 500 2750 3%
Third Gear 50 2750 21%
FourthGear Nil Nil 75%
 Solution
Given: N= 1750 rpm Co = 11600N C= 17600N Lh = 4000h

Equivalent load for complete work cycle Gear Axial Load(N) Radial Load (N) %time engaged
First Gear 3250 4000 1%
Second Gear 500 2750 3%
Third Gear 50 2750 21%
Fourth Gear Nil Nil 75%
Firstgear
Fa 3250
=0.8125
VE, F 4000

3250
and = 0.28
11600

From Table 15.4, it is observed that the value of e will be from 0.37 to 0.44.

From Table 13.7, it is observed that the value of e will be from 0.38

Factors for Deep-Groove Ball Bearings Table 15.4 Aand Y ha tar Át S n e

Trail irurm
FJVE, S e F/VE, > e
X Y
FJC, )

0.014 0.19 2.30 0025 0.56 0

0.21 0.21 2.15 0.0H0 0

0 070
O.028 0.22 199

O C42 024 185

0

O56 0.26 1.71

O70 0.27 1.0 0.56 1.63

0.28 1.55
0.110 0.30 1.45
017 0.34 1.31
028 0.36
042 0.42
0,44

Bawed on Bamberges, EN al. Iie Adjust atorstr Ball ant Klle

Brang Anlngmng DesguGuutr, NewYork, ASME, I971
 pemisSIon)
FAG Bearing Catalogue, with
TABLE 13-7 ctors und )' or Radial Bearings. (From
Single row Double row bearings
bcarings
>e
F,
F, F,
X
Y X Y
Bcnng tyTe

Fa F,
C iZD;
Radial
2.30 0.19
Contat 0.014 25 2.30
L.99 0.22
Goove 0.028 50 1.99
I.71 0.26
Ball 0.056 100 1.71
Bearings L.55 0.28
0.084 150 1.55
0.11 200 0.56 145 1 0.56 I.45 0.30
0.17 300 131 L.31 0.34
0.28 S00 1.15 1.15 0.38
0.42 750 L.04 I.04 0.42
0.56 1000 1.00 L.00 0.44
20 0.43 L.00 1.09 0.70 L.63 0.57
25 0.41 0.87 0.92 0.67 L.44 0.68

Single nw
berings' Double row beanings
F
F

Bearing lype
0.39 (0.76 0.78 0.63
0.S0
35 037 0,66 0.66 0.60 L.07 0,9$
035 (0 67 (055 0.57 (093 1.14
0 40 04 cot 042 cOt
Self-Aligning S nY
Ball Beafings
) 40 04 cot (0 45 col?
Spherical and (067
1.5 (an
Taperal Roller Beaings
For sngle row heanngs, wheneue.A
hwanpgs untcd "'lac-w-fwe r "hack-o-back uM the valuCs of. and Y
For (ko single rOW angular conuCt ball or ollg which apply to double roW
tlic valucs olN anl wheh apply to iugle row ben
beurings. For (wo or more sngle nw beanug» ounted "n undem" use
Double row beurings ure presumed to he symneuical.
nunber of oll1ng elonents/rs, D, -hall diamete.
C,=statie loud rating, i - number of rows of rolling clements.
the beanng ublev.
Y values for tapered ruller beringN are shun n
 Table 15.4 X and Yfactors for single-row decp
Fa groove ball bearings
Here
VE,
->e
a
e) ) ) )
Hence( From Table 15.4)
0.025 0.56 2.0 0.22
X= 0.56 0.040 0.56 |8 0.24

0.070 0.56 0.27

The value of factor Y is obtained by linear 0.130 0.56 |4 0.31

nterpolation. 0.250 0.56 I.2 0.37

0.56 L.0 0.44
Y=1.2 (1.2-1.0) x(0.28-0.25) = 1.176 0.500

(0.5 -0.25)
Service factor/load factor/ shock factor not the
Fe1 = (XV, + YF)C static load capacity
= XF, + YF, =0.56(4000) + 1.176(3250)
= 6062N

Second gear Third gear

= 0.182 = 0.0182

500
and = 0.0431
and = 0.00431

From Table 15.4, it is observed that the

value of e will be from 0.24 to 0.27.
From Table 15.4, it is observedthat the
value of e will be 0.22 or less.
Fa <e
VE, (use 0.014 if<0.014 and hence e=0.19)
VE,
Hence, from table X=1, Y=0 Fa <e
Fez = (XVE, + YF)C;
Pe3 = (XV}, + YF,DC;
Fe2 = F =2750N Pes = ; = 2750N
 11/a
Fourth gear |Fl, + Fl2 t F3l3
Fe = (l, + l, + l3)
Fes = 0
Considering the work cycle of 17.5(6062)' +52.5(2750) + 367.5(2750) +1312.5(0)
one minute duration, 1750

(1750) = 17.50 rev. F = 1932.67 N

100
3
l,= -(1750) = 52.50 rev.
100
21
l3= 1750)= 367.50rev.
l4 75 (1750) = 1312.50 rev. 17600
3

100 = 755.2m. o.r

L10 =
(l, + l4 + l3 + l¡)= 750rev. 1932.67)

L = a4azagb10 Roo = 0.9 and b = 1.17

1 L = 60N L,/106
In
R
a, = 1
Lh =4000h N= 1750rpm
1
1 LA =60 ×1750X 4000/100 = 420 m. o.r
(n R
LA = 1 LË0
n Roo 1

ln |n Roo
LA R
1
Ly0 |n Rgo R= 0.9483 or 94.83%
Problem

ball bearing operates on the following work cycle:

A
Element time
Element No Radial Load(N) Speed(rpm)
(%)
1 3000 720 30
2 7000 1440 50

5000 900 20
3

Calculate
The dynamic load capacity of the bearing is 16.6 KN.
i. The average speed of rotation:
ii. The equivalent radial load; and
iii. The bearing life.
200 hours of operation.
iv. The bearing is expected to be in use for
Find out the reliability with which the life couldbe expected.

Equivalent load for complete work cycle

Consider the work cycle of one minute duration Revolutions
Element Element time Speed
(sec.) (r.p.m.) in clennent ume
No. (N)
3000 720 216

7000 30 1440 720

1/a 900 Is0
3 S000
| F ,+ F%l2 + Fsl3 total
F = (l, + lz + l3)
Total (6)

Average speed of rotation

216(3000)'+ 720(7 000)' +180(5000)"
Average specd of rotation=1116r.p.m.

= 6271.57 N
 18-10

Bearing life (L1oh)

l6.6x10 = 18.54 million rev.
Lw 6271.57

L1oh = L10 X 10/60n = 276.94 hr

LhA Inp
\La10 1
Ln Roo

Problem: Aball bearing subjected to a radial load of 3000 Nis expected to have satisfactory life of 10000h
at 720 rpm with areliability of 95%. Calculate the dynamic load carrying capacity of the bearing, so that it
can be selected from a manufacturer's catalogue based on the 90% reliability. If there are four such bearings.
cach with areliability of 95% in a system, what is the reliability of the complete system

1
Bearing life for 95% reliability
1
R Lg5 n60L9sh = 432 m.o.r.
1
106
ln 1
Roo 1.17

Lg5 n o.95
In R L0 1
= 0.5405
1 LË0

Los 133
LA In 0.545 0.545 -799,26 m.o.r
1
L10 n Roo
Dynamic load carrying capacity
C=F (L)=3000(799.26)' =27 840.94 N

System reliability

R, = (R) = (0.95) = 0.8145 Or 81.45%

with rolling bearings and loads is shown in Sketch f. The bearings are
Problem :A shaft
forces caused by the external loads are
mounted such that both the axial and radial
cylindrical with no flange on the inner
absorbed. For bearing NU205ECP the geometry is
only radial load can be absorbed. The full axial thrust load Pa is thus taken
race. so that
deep-groove balI bearing 6205. Determine the Lo lives of each of the Iwo
up by the
bearings whileassuming length dimensions are in meters.
Bearin9 1000
Beec
NU 6205

500

02 02

Skotch Llor Problerm 13 53

 18

Problem
cylindricalroller bearing
gearbox is shown in Figure 1. Bearing Ais a Bearing B is a
1aring aTangement for a shafi in a nmm, width 1|mm,
and C= 12,500 N.
35
0! CP) wh bore dia I` mm, outside dia outside dia = 100 mm, width = 25
mm, C= 55,300 N,
(6309) with bore dia =45 mm.
dovp-gOe ballbearing 4000 N
andc 1`00 N Length dimensions are in millimeters. -300
2500 N
1000 N

200 4

inner-race, rolling element contact,

bearings have the samecomposite surface roughness of the
Inese th0 0.5
of the inner race is 9.65 mm, the roller
(R + R6) =0.10 um. For bearing NU202ECP at A. the outer radius
outer race is 15.35 mm. For
length and diameter is 8.5 mm and 5.7 mm respectively. and inner radius of the inner radius
27.4 mm, and the
bearing 6309 at B, the ball diameter is 17 mm, the outer radius of the inner race is
ring is 0.53 while for
of the outer race is 44.4 mm. The race conformity(radius of groove/dia of ball) for the outer
the inner ring it is 0.52. The lubricant used has the absolute viscosity of 0.1 N-s/m² and the pressure-viscosity
coefficient =2 xl0-m²/N. The bearing rotational speed is 5000 rpm. The cylindrical roller bearing has 13 rollers
and the ballbearing has 10 balls. The ball bearing is made of AISI 440C (E =200 GPa, p =7650 Kg'm'). and the
rollerhearing is made of AISI 52100 (E - 207 GPa, 7810 Kg/m³ ); both materials have poison's ratio =0.3.
Determine the adjusted life of both the bearings to predict, which bearing will fail first.

R,

ER, G= a'

PR: