Post on 02-Jun-2018
transcript
8/10/2019 Bearings-131 Part 1
1/74
S.Mekid 1
Equivalent load
1
Except for pure thrust bearings and cylindrical roller
bearings, all other bearings are usually operated with
somecombinationof radialFrand thrust loadF
a.
Since catalog ratings are based only on radial loading (oronly on thrust loading),an equivalent radial loadF
emust
be calculated.
Remember equivalent stress
8/10/2019 Bearings-131 Part 1
2/74
S.Mekid 2
Equivalent load
2
efD FaF
The equivalent radial loadFe(for radial bearings) is calculated
using the following AFBMA equation:
airie FYVFXF
The design Load is thus:
FD Design Load
af Application Factor (service factor) obtained from table 11.5
Fe Radial Equivalent loadFr Radial load
Fa Axial (thrust) load
V Rotation factor (V = 1 for rotating inner ring, V= 1.2 for outer ring )
Xi & Yi respectively radial and thrust load factors obtained from table 11.1
8/10/2019 Bearings-131 Part 1
3/74
S.Mekid 3
Equivalent load
3
Variation of Equivalent Load
with thrust (axial) Fa( Figure
11.6 see Table 11.1).
8/10/2019 Bearings-131 Part 1
4/74
S.Mekid 4
Bearing Selection
4
8/10/2019 Bearings-131 Part 1
5/74
S.Mekid 5
Bearing Selection
5
Only to ball, straight roller and spherical roller bearings
8/10/2019 Bearings-131 Part 1
6/74
S.Mekid 6
Sample Problem on Bearing Selection
6
Select a ball Bearing for an industrial machine intended for
continuous one-shift 8-h/day operation at 1800 rpm.
The radial and thrust loads are 1.7 and 1.2 kN
respectively.
The machine operates with light to moderate impact
The desired reliability is 95%.Given
1. Ball bearing (a = 3)
2. Machine working 8-hr continuous (table 11.4)
3. nD
= 1800 rpm
4. Fr= 1.7 kN
5. Fa= 1.2 kN
6. Light to moderate impact
7. R = 0.95
Required:
Select ball bearing (C10?)
8/10/2019 Bearings-131 Part 1
7/74
S.Mekid 7 7
6.0)95.01(439.402.0
)1(439.402.0
483.1/1
483.1/1
DR
RK
a
R
DDKxFC
/1
10
483.1/1)1(439.402.0 DR RK
324010
60180030000
60
60/
610
RR
DDD
nL
nLLLx
Table 11.4 take highest to be conservativeBall bearing
5115.1
tablefroma
FaF
f
efD
Now the problem is finding the equivalent load Fe
Sample Problem on Bearing Selection
8/10/2019 Bearings-131 Part 1
8/74
S.Mekid 8
PROCEDURE:
Compute Equivalent Load?
SELECTION?
?7.17.11111 MaxkNVFXF re
2.17.1156.0 2222 YFYVFXF are1stIteration:1. Assume a value mid-range from Table 11.1: Y2=1.71or 1.63
Another method is to start from table 11.2 directly selecting candidate bearing
2. Compute Fe2:
3. Compute C10:
4. Select candidate bearing from Table 11.2 (02-series)
a. Try deep groove first (cheaper, easier to mount) C=83.2 kN and C0
=53 kN
b. If angular contact is considered: C=80.6 kN and C0=55 kN
kNFkNF ee 7.104.32.17.1156.0 12 71.1
kNK
xFC
a
R
DD 05.80
6.0
32405.104.3
3/1/1
10
Y2=?
8/10/2019 Bearings-131 Part 1
9/74
S.Mekid 9 9
21.00218.055
2.1
Re)(71.199.1
22.00226.053
2.1
0
2
0
eC
F
peatAssumedYtheneVF
F
eC
F
a
r
a
aFor Deep-Groove Bearing
For Angular Contact Bearing
2ndIteration:2. Compute Fe2:
3. Compute C10:
4. Select candidate bearing from Table 11.2 (02-series)
a. Try deep groove first (cheaper, easier to mount) C= 95.6 kN and C0= 62 kN
b. If angular contact is considered: C=90.4 kN and C0=63kN
kNFkNF ee 7.134.32.17.1156.0 12 99.1
kNK
xFC
a
R
DD 9.87
6.0
32405.134.3
3/1/1
10
8/10/2019 Bearings-131 Part 1
10/74
S.Mekid 10 10
For Deep-Groove Bearing
For Angular Contact Bearing
3rdIteration:2. Compute Fe2:
3. Compute C10:
4. Select candidate bearing from Table 11.2 (02-series)
a. Try deep groove first (cheaper, easier to mount) C= 95.6 kN and C0= 62 kN
b. If angular contact is considered: C= 90.4 kN and C0= 63kN
kNFkNF ee 7.142.32.115.27.1156.0 12
kNK
xFC
a
R
DD 90
6.0
32405.142.3
3/1/1
10
21.0019.063
2.1
Re)(99.115.2
21.0019.0
62
2.1
0
2
0
eC
F
peatoldYtheneVF
F
e
C
F
a
r
a
a
8/10/2019 Bearings-131 Part 1
11/74
S.Mekid 11 11
Since the 3rdbearing is the same as the 2ndwe stop and summarize:
02 series deep-groove ball bearing with load rating of 95.6 kN
and dimensions: d = 90 mm, D = 160 mm and W = 30 mm is the
suitable bearing for the application.
02 series angular contact ball bearing with load rating of 90.4
kN and dimensions: d = 90 mm, D = 160 mm and W = 30 mmmay also be selected for the application.
Note that in solving this problem no constraints concerning the
size of shaft and housing were considered. In reality, shaft and
housing dimensions are considered in the selection of bearings.
Tables 11.2 and 11.3 do not allow the freedom for such selection
but real catalogs do as shown in following SKF catalog tables.
8/10/2019 Bearings-131 Part 1
12/74
S.Mekid 12 12
Bearing SelectionTable 11-2
8/10/2019 Bearings-131 Part 1
13/74
S.Mekid 13 13
Bearing SelectionTable 11-3- Straight (Cylindrical) Roller Bearings
8/10/2019 Bearings-131 Part 1
14/74
S.Mekid 14
Bearing Selection
14
8/10/2019 Bearings-131 Part 1
15/74
S.Mekid 15 15
Bearing Selection
Principal Dimensions Basic load ratings Allowable
load limit
Speed ratings Abutment and fillet
Dimensions
Designation
db da bw
dynamic
C
static
C0 wall
grease oil
Db,min Da,max ra,max
mm
in
mm
in
mm
in
N
lbf
rpm mm
in
mm
in
mm
in
2.5
0.0984
8
0.3150
2.8
0.1102
319
71.7
106
23.8
4
0.899
67000 80000 3.7
0.146
6.8
0.268
0.1
0.004
60/2.5
5
0.1969
11
0.4331
3
0.1181
637
143
255
57.3
11
2.47
53000 63000 6.2
0.244
9.8
0.386
0.1
0.004
618/5
190.7480
60.2362
1720387
620139
265.85
36000 43000 70.276
170.669
0.30.012
635
7
0.2756
14
0.5512
3.5
0.1378
956
215
400
89.9
17
3.82
45000 53000 8.2
0.323
12.8
0.504
0.1
0.004
618/7
10
0.3937
19
0.7480
5
0.1969
1380
310
585
132
25
5.62
36000 43000 12
0.472
17
0.669
0.3
0.012
61800
26
1.0236
8
0.3150
4620
1040
1960
441
83
18.7
30000 36000 12
0.472
24
0.945
0.3
0.012
6000
35
1.3780
11
0.4331
8060
1810
3400
764
143
32.1
20000 26000 14
0.551
31
1.220
0.6
0.024
6300
15
0.5906
24
0.9449
5
0.1969
1560
351
800
180
34
7.64
28000 34000 17
0.669
22
0.866
0.3
0.012
61802
28
1.1024
7
0.2756
4030
906
2040
459
85
19.1
24000 30000 17
0.669
26
1.024
0.3
0.012
61902
32
1.2598
8
0.3150
5590
1260
2850
641
120
27.0
22000 28000 17
0.669
30
1.181
0.3
0.012
16002
32
1.2598
9
0.3543
5590
1260
2850
641
120
27.0
22000 28000 17
0.669
30
1.181
0.3
0.012
6002
35
1.3780
11
0.4331
7800
1750
3750
843
160
36.0
19000 24000 19
0.748
31
1.220
0.6
0.024
6202
42
1.6535
13
0.5118
11400
2560
5400
1210
228
51.3
17000 20000 20
0.787
37
1.457
1
0.039
6302
See Tables 11.2 for BB
11.3 for SRB
1998 McGraw-Hill
Single Row, Deep Groove Ball Bearings[From SKF Catalog (1991)]
with full outer
ring shoulders
with recessed outer
ring shoulders
ra
dadb
bw
Da Db
8/10/2019 Bearings-131 Part 1
16/74
S.Mekid 162010/2011 Chapter 11-Notes 16
1998 McGraw-Hill
Single Row Deep Groove Ball Bearings20-30 mm
Principal Dimensions Basic load ratings Allowableload limit
Spe ed ratings Abutm ent and filletDimensions
db da bw
dynamicC
staticC0 wall
grease oilDb,min Da,max ra,max
mmin
mmin
mmin
Nlbf
rpm mmin
mmin
mmin
200.7874
321.2598
70.2756
2700607
1500337
6314.2
19000 24000 220.866
301.181
0.30.012
371.4567
90.3543
63701430
3650821
15635.1
18000 22000 220.866
351.378
0.30.012
421.6535
80.3150
68901550
4050910
17338.9
17000 20000 220.866
401.575
0.30.012
421.6535
120.4724
93602100
50001120
21247.7
17000 20000 240.945
381.496
0.60.024
47
1.8504
14
0.5512
12700
2860
6550
1470
280
62.9
15000 18000 25
0.984
42
1.654
1
0.03952
2.047215
0.5906159003570
78001750
33575.3
13000 16000 26.51.043
45.51.791
10.039
722.8346
190.7480
307006900
150003370
640144
10000 13000 26.51.043
65.52.579
10.039
250.9843
371.4567
70.2756
4360980
2600585
12528.1
17000 20000 271.063
351.378
0.30.012
471.8504
120.4724
112002520
65501470
27561.8
15000 18000 291.142
431.693
0.60.024
622.4409
170.6693
225005060
116002610
490110
11000 14000 31.51.240
55.52.185
10.039
803.1496
210.8268
358008050
193004340
815183
9000 11000 331.299
722.835
1.50.059
301.1811 421.6535 70.2756 44901010 2900652 14632.8 15000 18000 321.260 401.575 0.30.01255
2.165413
0.5118133002990
83001870
35579.8
12000 15000 351.378
501.969
10.039
722.8346
190.7480
281006320
160003600
670151
9000 11000 36.51.437
65.52.579
10.039
903.5433
230.9055
436009800
236005310
1000225
8500 10000 381.496
823.228
1.50.059
Bearing Selection
8/10/2019 Bearings-131 Part 1
17/74
8/10/2019 Bearings-131 Part 1
18/74
S.Mekid 18
Tapered Roller Bearings
2008/2009 Ch 11. Notes 18
Cup Can be easily removedfrom cone and
roller assembly because of this and
because even a pure radial load willinduce a thrust load because of the
taper TRB have to be mounted in
pairs:
Back to Back (Direct mounting)
Front to Front (Indirect mounting)
Timken Co.Data shows that the induced
thrust force can be estimated from Eq.
11-15:
Nomenclature
K
FF ra o
47.0)180(
K =ratio of rated radial to rated thrust
load approximated 1.5 for radialTRB
and 0.75 for steep angle bearings
Span
8/10/2019 Bearings-131 Part 1
19/74
S.Mekid 19
Selection of Tapered Roller Bearings
The load rating for Timken Co. tapered roller bearings is
calculated as follows:a
RRRvT
DDf
nLKff
nLPaCC
/1
1090
60
60
For Timken Co. Catalogs:
LR
= 3000 Hours and nR
= 500 rpm (3000500 x60
= 90.10 6revolutions)
FD= a
fP
P is calculated as follows
3/25.1/1 )1(48.4))/1(ln(48.4 DDR RRK
8/10/2019 Bearings-131 Part 1
20/74
S.Mekid 20
Selection of Tapered Roller Bearings
8/10/2019 Bearings-131 Part 1
21/74
S.Mekid 21 21
X
O
Selection of Tapered Roller Bearings
X
O
8/10/2019 Bearings-131 Part 1
22/74
S.Mekid 22
Indirect mounting
Direct mounting
Indirect mounting
provides greater rigidity
when pair of bearings is
closely spaced: front
wheel of a car, drums,
sheaves,..
Direct mounting
provides greater rigidity
when pair of bearings is
not closely spaced:transmission, speed
reducers, rollers,..
X
O
8/10/2019 Bearings-131 Part 1
23/74
S.Mekid 23
Selection of Tapered Roller Bearings
23
fV= Viscosity factor obtained from figure 11.17.
8/10/2019 Bearings-131 Part 1
24/74
S.Mekid 24
fT=Temperature factor
estimated from figure(11-16):
Selection of Tapered Roller Bearings
8/10/2019 Bearings-131 Part 1
25/74
S.Mekid 25
8/10/2019 Bearings-131 Part 1
26/74
S.Mekid 26 26
8/10/2019 Bearings-131 Part 1
27/74
S.Mekid 27 27
Solved Example
8/10/2019 Bearings-131 Part 1
28/74
S.Mekid 28 28
Direct
mount
Shaft + right
to Left
8/10/2019 Bearings-131 Part 1
29/74
S.Mekid 29 29
8/10/2019 Bearings-131 Part 1
30/74
S.Mekid 30 30
8/10/2019 Bearings-131 Part 1
31/74
S.Mekid 31
Mountingand Enclosure of Bearings
31
Alternative Mounting
dsdH
Positioning Floating
Takes thrust
No thrust and allows for
shaft expansion when hot
Retaining nuts on inner ringNo retaining devices on inner ring
Outer races completely retained
Shoulders in shaft and housing: See tables 11.2
and 11.3 for dimensions
8/10/2019 Bearings-131 Part 1
32/74
S.Mekid 32 32
Use of 2 or more bearingsin one end of shaft for
additional rigidityor increased load capacity.
Mountingand Enclosure of Bearings
8/10/2019 Bearings-131 Part 1
33/74
S.Mekid 33 33
Two-bearing mounting with use
of washers against cone
Mountingand Enclosure of Bearings
8/10/2019 Bearings-131 Part 1
34/74
S.Mekid 34 34
Duplex Mountingof angular contact bearings: Bearings manufacturedfor this purpose have their rings ground with an offset so that they are
tightly clamped together and apreloadis automatically established
(as you have seen on the animation).
a) Face to face mounting (DF)for heavy Fr
and Fa
from either direction
b) Back to back mounting (DB)=a)+ aligning stiffness
c) Tandem arrangement (DT)for thrust which is always in the same
direction. Preload required.
Mountingand Enclosure of Bearings
8/10/2019 Bearings-131 Part 1
35/74
S.Mekid 35 35
8/10/2019 Bearings-131 Part 1
36/74
S.Mekid 36
Mountingand Enclosure of Bearings
http://www.toydirectory.com/monthly/new_product.asp?id=251638/10/2019 Bearings-131 Part 1
37/74
S.Mekid 37
http://www.toydirectory.com/monthly/new_product.asp?id=23961http://www.toydirectory.com/monthly/new_product.asp?id=251638/10/2019 Bearings-131 Part 1
38/74
S.Mekid 38
Needs preloadingSee p. 600.
Mountingand Enclosure of Bearings
8/10/2019 Bearings-131 Part 1
39/74
S.Mekid 39
Low speeds Moderate to high speedsHigh to very
high speeds
spring
rubber
Mountingand Enclosure of Bearings
8/10/2019 Bearings-131 Part 1
40/74
S.Mekid 40
Lubrication
40
Elastohydrodynamic lubrication:Remember the movie showing athin film (mm) of oil between rolling elements subjected to
extreme pressures is transformed from a liquid lubricant (oil) into
a solid for a nano fraction of a second.
(from presentation by Saeed S. Aramco)
8/10/2019 Bearings-131 Part 1
41/74
S.Mekid 41
Liquids (oils)
Semi-Liquids (greases)
Solids (Graphite)
41
Types of Lubricant
See Page 597 of text book for conditions
8/10/2019 Bearings-131 Part 1
42/74
S.Mekid 42 42
Mineral
AdditivesBase Oil
Synthetic
NaphthenicParraffinic
Lubricating Oil
(from presentation by Saeed S. Aramco)
8/10/2019 Bearings-131 Part 1
43/74
S.Mekid 43 43
Grease
BaseOil Thickener Additives
70 90
%
3 30
%1 10
%
o Simple Metal Soapso Complex Metal Soap
o Non-Soap
(from presentation by Saeed S. Aramco)
8/10/2019 Bearings-131 Part 1
44/74
S.Mekid 44
Common Oil Physical and Chemical Properties
Color Appearance
Flash point
Pour point
TAN
TBN
Density
Oxidation stability Viscosity
Viscosity Index
44
8/10/2019 Bearings-131 Part 1
45/74
S.Mekid 45
Common Oil Physical and ChemicalProperties
Appearance Flash Point
Pour Point
TAN TBN
Density
Specific Gravity Viscosity
Viscosity Index
2008/2009 Ch 11. Notes 45
8/10/2019 Bearings-131 Part 1
46/74
S.Mekid 46
FAILURE OF BEARINGS
Failure causes1. - Manufacture and assembly
Mounting with improper tools,
Loose/tight fits, Misalignment, ...2. - Design and Operating conditions
Bad selection, Overload, Fatigue, ...
3. - LubricationUnsuitable/ excess/ lack, Contamination
8/10/2019 Bearings-131 Part 1
47/74
S.Mekid 47
FAILURE OF BEARINGS
Failure modes
Fracture/Separation
Spalling, Cracks, Smearing, Seizing,
DeformationIndentations, Brinnelling, Fluting,
Wear
Abrasive, Burning, Scuffing, ...
Corrosion
Etching, Fretting, Rust Staining
8/10/2019 Bearings-131 Part 1
48/74
S.Mekid 48Ch 11. Notes 48
Table 10
Failure Causes of Rolling and Plain Bearings [5]
Failure Cause Occurrence, %
Rolling Plain
Bearings Bearings
Vendor problems 30.1 23.4
Workmanship 14.4 10.7
Errors in design/applications 13.8 9.1 Wrong material of construction 1.9 3.6
User-induced problems 65.9 69.6
Operational errors, maintenance
deficiencies, failure of monitoring 37.4 39.1
equipment
Wear 28.5 30.5
External problems 4.0 7.0
Contaminated lubricants; intermittent
failure of oil supply system 4.0 7.0
8/10/2019 Bearings-131 Part 1
49/74
S.Mekid 49
FATIGUE FAILURE
49
VIDEOS 1 & 3
Simulation of progression of
8/10/2019 Bearings-131 Part 1
50/74
S.Mekid 50
Simulation of progression offatigue failure
50
Hamrock , J acobson and SchmidMcGraw-Hil l 1998
Fatigue Wear
.
Text Reference: Figure 8.2 2, page 346
FATIGUE (E d f f l lif ) S lli
8/10/2019 Bearings-131 Part 1
51/74
S.Mekid 51 51
FATIGUE (End of useful life) Spalling
Progression of fatigue failure.
Spot
Flaking Failure-Noise
8/10/2019 Bearings-131 Part 1
52/74
S.Mekid 52
FATIGUE- Spalling
52
P i
8/10/2019 Bearings-131 Part 1
53/74
S.Mekid 53
Prevention
53
Fatigue failure cannot be prevented, but it can be
delayed by taking three steps:
1. Make sure that the replacement bearing is designed
to take the desired load.
2. Protect the bearing from damage and keep it clean
during the installation.
3. Lubricate adequately.
Mi li t
8/10/2019 Bearings-131 Part 1
54/74
S.Mekid 54
Misalignment
54
Certain types of bearings cantolerate only limited amounts
of misalignment.
In deep groove ball bearings
misalignmentwill produce
load zones not parallelto ballgroove which can be detected
easily.
MISALIGNMENT
8/10/2019 Bearings-131 Part 1
55/74
S.Mekid 55 55
MISALIGNMENT
Advanced spalling
caused by edge loading.
In cylindrical and tapered roller bearings
edge-load caused by misalignment causespremature spalling.
Fatigue caused by edge loading.
P ti
8/10/2019 Bearings-131 Part 1
56/74
S.Mekid 56
Prevention
56
1. Make sure that the component is correctly aligned
during installation
2. Inspect shaft for any bowing
3. If new or modified design, the distance between bearings
should be determined by deformation analysis.
4. Make sure that bearing seat is smooth
5. After bearings are in place the shaft should be aligned
with the machine6. Whenever possible use correct self-aligning bearings
Lubrication related failures
8/10/2019 Bearings-131 Part 1
57/74
S.Mekid 57
Lubrication-related failures
57
1. Inadequate lubricationis the cause of a large
number of bearing premature failures.
2. Inadequate lubrication will cause surface damage
such as roughening, frostingleading to spalling.
3. Inadequate lubrication will cause discolorationof the surface
Spalling and discolration caused by
8/10/2019 Bearings-131 Part 1
58/74
S.Mekid 58
p g yinadequate lubrication
58
Progressive stages of spalling Dislocationcaused by
inadequate lubrication
Inadequate lubrication
8/10/2019 Bearings-131 Part 1
59/74
S.Mekid 59
Inadequate lubrication
59
Discolorationcaused by inadequate lubrication
Contamination & Improper
8/10/2019 Bearings-131 Part 1
60/74
S.Mekid 60
p pLubrication
60
The bearing failureappears to have beencaused by eitherabrasive wear from theintroduction of fineforeign particles and /or
over-lubrication
The failed rollers weresubjected to contactfatigue followed by heatchecking
Optimize frequency oflubrication and amountof clean grease
Contamination & Corrosion
8/10/2019 Bearings-131 Part 1
61/74
S.Mekid 61
Contamination & Corrosion
Corrosion results from the
chemical attack on bearingmaterials.
Symptoms include
red/brown areas on rollingelements, raceways, orcages.
Corrosion usually resultsin increased vibrationfollowed by wear, withsubsequent increase inradial clearance
61
Prevention
8/10/2019 Bearings-131 Part 1
62/74
S.Mekid 62
Prevention
62
1. Make sure that the correct Manufacturer specified type o
lubricant is used.
2. Sufficient elastohydrodynamic film prevents surface distress
(glazing, pitting).
3. Good boundary lubrication guards against smearing and sliding
surface wear.
4. Clean lubricants prevent significant wear of rolling surfaces.
5. Sufficient lubricant flow keeps bearings from overheating.
6. Change the oil or grease in the bearing according
Manufacturers schedule.
Mounting Related Failures
8/10/2019 Bearings-131 Part 1
63/74
S.Mekid 63
Mounting Related Failures
63
Fatigue from chipin bore Fragment denting
Improper mounting practices can cause:
1. Smearing or fragment denting2. Fatigue spalling (dirt)
3. Impact damage
Mounting Related Failures
8/10/2019 Bearings-131 Part 1
64/74
S.Mekid 64
gSmearing
64
Smearing caused by excessive
force in mountinga cylindrical
roller bearing.
(X 8) Enlargement ofsmearing.
Mounting Related Failures
8/10/2019 Bearings-131 Part 1
65/74
S.Mekid 65
gParasitic Thrust
65
Spalling from parasitic thrust (self-alignment bearing)
Damage due to improper fits
8/10/2019 Bearings-131 Part 1
66/74
S.Mekid 66
Damage due to improper fits
66
The degree of tightness or looseness is
Governed by both the levels of load and speed.
In general the rotating ring is mountedwith interference fitand the non-rotating
ring with slip-fit.
Damage due to improper fits
8/10/2019 Bearings-131 Part 1
67/74
S.Mekid 67
(Scoring)
67
Scoringof inner ring caused by creep, relative
movement between ring and shaft.
Damage due to improper fits
8/10/2019 Bearings-131 Part 1
68/74
S.Mekid 68
Damage due to improper fits(Wear)
68
Wear due to creep. Brilliant polish due to lubrication
penetration between ring and shaft seating. Face of ring
is also damaged by shaft shoulder.
Damage due to improper fits
8/10/2019 Bearings-131 Part 1
69/74
S.Mekid 69
Excessive Interference Fit
69
Axial crackscaused by excessive
interference fit.
Damage due to improper fits
8/10/2019 Bearings-131 Part 1
70/74
S.Mekid 70
Fretting Corrosion
70
Wear due Fretting corrosion
caused by unnecessary loose
housing fit.
Advanced Wear due to
Fretting corrosion.
Damage due to improper fits
8/10/2019 Bearings-131 Part 1
71/74
S.Mekid 71
Damage due to improper fits
71
Crack caused by faulty
housing fit.
Fretting caused by yield.
Electric Fluting
8/10/2019 Bearings-131 Part 1
72/74
S.Mekid 72
Electric Fluting
Findings:
The bearing hadundergone anincipient stage of
electrical pitting(fluting)
Recommendations:
Insulate thebearings properly
72
Other causes of failure
8/10/2019 Bearings-131 Part 1
73/74
S.Mekid 73
Other causes of failure
73
Electric current arcing
Ineffective sealingVibration
References
8/10/2019 Bearings-131 Part 1
74/74
References
1. J. E. Shigley and C. R. Mischke, Mechanical EngineeringDesign,McGraw-Hill, 2004 (7thEd.)
2. J. E. Shigley and C. R. Mischke, Mechanical EngineeringDesign,McGraw-Hill, 2000 (6thed.).
3. J. E. Shigley and C. R. Mischke, Standard Handbook ofMachine Design,McGraw-Hill, 1986.
4. B. J. Hamrock, B. Jacobson and S. R. Schmid,Fundamentalsof Machine Elements, McGraw-Hill,1999.
5. R. C. Juvinall and K. M. Marshek Fundamentals of Machine
Component Design,John Wiley & Sons, 2000 (3rd ed.). 6. H. P. Bloch and F. K. Geitner, Machinery Failure Analysis
and Troubleshooting, Vol.2, 2nd Ed., Gulf PublishingCo., USA, 1994.