3. • Rolling Contact Bearings
• Sliding Contact Bearings

4. W
Hydrodynamic
bearings
W
Hydraulicoil
Hydrostatic
bearings

5. • Ball bearings
 Single row ball bearing
 Double row ball bearing
 Self alignment ball bearing
 Angular contact ball bearing
 Thrust ball bearing
• Roller contact bearings
 Taper roller bearing
 Straight roller bearing
 Conical roller bearing
 Concave roller bearing
 Thrust roller bearing
 Needle bearings

6. Ball bearing
Ball
thrust
bearing
Roller thrust
bearing
Roller bearing
Spherical roller
thrust bearing
Radial tapered
roller bearing

7. The loading on bearings can be classified into
threegroups:
 Solely radial loading
 Solely axial loading
 Combined radial and axial loading

8. Extra
light
Light Medium Heavy

9. STANDARDISATION OF BALL BEARINGS :
• Light : 200
• Medium: 300
• Heavy : 400
6309
Bearing type
Bore diameter
Series number

10. Inner ring
Ball Ball retainer
Outer ring

11. •The bearing must be of the series best suited to the
installation, in regard to both:
•capacity and
•dimensions.
•The type of bearing selected must be suitable for the type of
imposed load,
•radial,
•thrust or
•combined.
•The size of the bearing must be such as to give the required
length of service with sufficient assurance.

12.  Bearings have to resist some combination of
radial and thrustloads.
 Combined load must be reduced to an equivalent
radial load
 In general the equivalent load Fe may be computed
by the equation:
 Fe XF r YFa
Type of bearing Y X
Deep groove 1.5 1
Angular contact 2 0.5
Self aligning 2.5 0.5

13.  Experiments have shown that the life of a ball bearing is a
function of the load it carries
.
e
n
F
L = ( C d
)3
– Cd: dynamic specific capacity of bearing.
– Ln: Life of bearing in millions of revolution.
– Fe : Equivalentload
 The above equation can be rewritten as
C 1 /3
d = Fe Ln

14. BEARINGLIFE Class of machine
Life in
working
hours
1
Instruments and apparatus that are used only seldom. Demonstration
apparatus, mechanisms for operating sliding doors
2 Aircraft engines 1000 - 2000
3
Machines used for short periods or intermittently and whose brake down
would not have serious consequences; hand tools, lifting tackles in
workshops, hand operated machines, generally agricultural machines,
cranes in erecting shops, domestic machines
4000 - 8000
4
Machines working intermittently and where breakdown would have
serious consequences. Auxiliary machines in power stations, conveyor
plant for flow production, lifts cranes for piece goods; machine tools
used infrequently
8000 - 12000
5
Machine for use 8 hours per day and fully utilized: stationary electric motors,
general purpose gear units.
12000 - 20000
6
Machine for use 8 hours per day and fully utilized: machines for engineering
industry generally: cranes for bulk goods, ventilating fans, countershafts
20000 - 30000
7
Machines for continuous use 24 hours per day: Separators, compressors,
pumps, mine hoist, stationary electric machines, machines in continuous
operations on board naval ships
40000 - 60000
8
Machines required to work with high degree of reliability 24 hours per day:
pulp and paper machinery; public power plants, mine pumps, pumps in water
works, machinery in continuous operation on board merchant ships
100000 - 200000

15. Load
conditions
Safety factor, life of 5 to 10 years
Safety
factor, life
of 10 to 20
years
Intermittent 10 hours per day Continuous Continuous
Steady load 0.5 ----- 1 1.5 2 3
Light shock 1 ------- 2 2.5 3 4
Moderate
shock
2 ------- 3 3.5 4 5
Severe shock 3-------- 4 4.5 5 6

16. SAE
Bearing
Number
Bore of inner race (d) Outside diameter D mm Width B (mm)
mm in
200
series
300
series
400
series
200
series
300
series
400
series
…… ……
…… ……
…… ……

17.  The shaft must be designed to take the inner
ring (race)., see fig. (6.7)
 A suitable mounting must be designed for
the outer ring (race).
 Lubrication must be provided for the bearing
 Methods of sealing the lubricant and
preventing penetration of foreign matter
must beprovided.

19. 16
 A shaft is supported by two bearings. One of the
bearings carries a radial load of 1200 lb and an axial
load of 600 lb with minor shocks. The shaft runs at
230 rpm and operates 10 hours per day for 5 days per
week. Select a suitable ball bearing with a service life
of 2 years if the diameter of the shaft can be varied
between 3 15and 3 1 inch.
2
Fr = 1200 lb
Fa = 500 lb
Speed = 230 rpm
Operating hours =10/day
Working days = 5/week
Years = 2
Minor shock

20. SELECT FACTOR OF SAFETY
FACTOR OF SAFETY = 2.5
Ln =
Continuous
3
4
3
2.5
5
4
3.5
6
5
4.5
3-------- 4
Severe shock

21. Fe = XFr+ Yfa
Load = 1 x 1200+1.5 x 600
Service Life(Ln)=

22. 
 101.01<d<88.9 mm
 From tables
 Select deep grove ball bearing
 SAE219 with dynamic capacity 17600
 Bore diameter = 95mm
3 15
<d<
16
3 1
2