This is a presentation on Bearings. if any one wants this contact me on moulik.parmar6@gmail.com.

1. BEARINGSBEARINGS
By - Moulik ParmarBy - Moulik Parmar

2. BEARINGS?BEARINGS?
 A bearing is a machine element which support another
moving machine element (known as journal).
 It permits a relative motion between the contact surfaces of
the members, while carrying the load.

3. WHY DO WE NEED THEM?WHY DO WE NEED THEM?
1. Reduce Friction
2. Carry Loads
3. Guide Moving Parts

4. FRICTION?FRICTION?
 Resistance to movement either it may be sliding or rotation.

5. SECTIONAL VIEWSECTIONAL VIEW

6. COMPONENTS OF BEARINGSCOMPONENTS OF BEARINGS

7. PROPERTIES OF SLIDING CONTACTPROPERTIES OF SLIDING CONTACT
BEARING MATERIALSBEARING MATERIALS
1. Compressive strength.
2. Fatigue strength.
3. Comformability.
4. Embeddability.
5. Bondability.
6. Corrosion resistance.
7. Thermal conductivity.
8. Thermal expansion.

8. MATERIALS USED FOR SLIDINGMATERIALS USED FOR SLIDING
CONTACT BEARINGCONTACT BEARING
1. Babbit metal.
2. Bronzes.
3. Cast iron.
4. Silver.
5. Non-metallic bearings.
 soft rubber bearings.
 wood bearings.

10. PROPERTIES OF LUBRICANTSPROPERTIES OF LUBRICANTS
1. Viscosity.
2. Oiliness.
3. Density.
4. Viscosity index.
5. Flash point.
6. Fire point.
7. Pour point or freezing point

11. LUBRICANTSLUBRICANTS
 Liquid(oil).
o Cheapness and stability.
 Semi-liquid(Grease).
o Slow speed and heavy pressure exist and
where oil drip from the bearing is undesirable.
 Solid.(Graphite).
o where oil films cannot be maintained because
of pressures or temperatures.

12. CLASSIFICATIONCLASSIFICATION
 Depending on Direction of load to be Supported.
1. Radial Bearing.
2. Thrust Bearing.
 Depending on Nature of Contact
1. Sliding Contact Bearing.
2. Rolling Contact Bearing.

13. TYPES OF BEARINGSTYPES OF BEARINGS

14. CLARIFICATIONCLARIFICATION

16. PLAIN BEARINGSPLAIN BEARINGS
 Plain bearing, also known by the specific styles: bushing,
journal bearing, sleeve bearing, rifle bearing.

17. ANTIFRICTION BEARINGSANTIFRICTION BEARINGS
BALL BEARINGS
•RADIAL BALL BEARING
•ANGULAR CONTACT BALL BEARING
 ROLLER BEARINGS
• CYLINDRICAL ROLLER BEARING
• TAPER ROLLER BEARING
• SPHERICAL ROLLER BEARING
• NEEDLE ROLLER BEARING

18. FORCES ACTING ON BEARINGFORCES ACTING ON BEARING
1. Radial Load.
2. Axial Load.
3. Combination of Radial & Axial Load.

19. RADIAL & THRUST BALL BEARINGRADIAL & THRUST BALL BEARING
 In radial bearings, the load acts perpendicular to the direction
of motion of the moving element.
 In thrust bearings, the load acts along the axis of rotation.

20. RADIAL & THRUST LOADRADIAL & THRUST LOAD

21. SOME MORE TYPESSOME MORE TYPES
 Jewel bearing, in which the load is carried by rolling the
axle slightly off –center.

22.  Fluid bearing, in which the load is carried by a gas or liquid.
 Magnetic bearing, in which the load is carried by a magnetic
field.

23.  Flexure bearing, in which the motion is supported by a load
element which bends.

24. ROLLER BEARINGSROLLER BEARINGS

25. NEEDLE ROLLER BEARINGSNEEDLE ROLLER BEARINGS

26. TYPES OF SLIDING CONTACTTYPES OF SLIDING CONTACT
BEARINGBEARING
 Guide Bearing:- The sliding contact bearings in which the
sliding action is guided in a straight line and carrying radial
loads, may be called slipper or guide bearings.
 Example:- Cross Head Of steam engine.

27.  Journal /Sleeve Bearing:- The sliding contact bearings in
which the sliding action is along the circumference of a circle
or an arc of a circle and carrying radial loads are known as
journal or sleeve bearings.
 When the angle of contact of the bearing with the journal is
360° then the bearing is called a full journal bearing.

28.  Partial Journal Bearing:- When the angle of contact of the
bearing with the journal is 120°then the bearing is said to be
partial journal bearing.
 Example:- Rail road car axle.
 The full and partial journal bearings may be called as clearance
bearings because the diameter of the journal is less than that of
Sliding Bearing.
 When a partial journal bearing has no clearance i.e. the
diameters of the journal and bearing are equal, then the
bearing is called a fitted bearing.

29. CLASSIFICATION ON BASIS OFCLASSIFICATION ON BASIS OF
LUBRICANT THICKNESSLUBRICANT THICKNESS
 Thick film bearings:- The thick film bearings are those in
which the working surfaces are completely separated from
each other by the lubricant. Such type of bearings are also
called as hydrodynamic lubricated bearings.
 Thin film bearings:- The thin film bearings are those in which,
although lubricant is present, the working surfaces partially
contact each other atleast part of the time. Such type of
bearings are also called boundary lubricated bearings.

30.  Zero film bearings:-The zero film bearings are those which
operate without any lubricant present.
 Hydrostatic or externally pressurized lubricated bearings:-The
hydrostatic bearings are those which can support steady
loads without any relative motion between the journal and the
bearing. This is achieved by forcing externally pressurized
lubricant between the members.

31. HYDRODYNAMIC LUBRICATEDHYDRODYNAMIC LUBRICATED
BEARINGSBEARINGS
 Load carrying ability of a hydrodynamic bearing arises simply
because a viscous fluid resists being pushed around.
 So on basis of load carrying capacity.
1. Wedge film lubrication
2. Squeeze film lubrication

32. WEDGE FILM JOURNAL BEARINGSWEDGE FILM JOURNAL BEARINGS
 The load carrying ability of a wedge-film journal bearing
results when the journal and/or the bearing rotates relative to
the load. Eg:- Static load bearings.

33. SQUEEZE FILM BEARINGSSQUEEZE FILM BEARINGS
 In certain cases, the bearings oscillate or rotate so slowly that
the wedge film cannot provide a satisfactory film thickness. If
the load is uniform or varying in magnitude while acting in a
constant direction, this becomes a thin film or possibly a zero
film problem. But if the load reverses its direction, the
squeeze film may develop sufficient capacity to carry the
dynamic loads without contact between the journal and the
bearing. Such bearings are known as squeeze film journal
bearing.

34. Journal Bearing
Types
Solid Journal Bearing

35. Journal Bearing
Types
Split Journal Bearing

36. Journal Bearing
Types
Half Bearing

37. Journal Bearing
Types
Tilting Pad

38. TILTING PAD DESCRIPTIVETILTING PAD DESCRIPTIVE

39. GUIDE VERTICAL FANGUIDE VERTICAL FAN
THRUST BEARINGTHRUST BEARING

40. BEARING LIFEBEARING LIFE

41. NOMENCLATURENOMENCLATURE

42. Clearance
Normal clearance Increased clearance
because of temperature
Reduced clearance
because of tight fit
Example:
6210/C3 = Deep groove ball bearing with
clearance greater than Normal
CN does not normally appear in the
bearing designation
clearance
less than C2
less than Normal
Normal
greater than Normal
greater than C3
greater than C4
Suffix
/C1
/C2
/CN
/C3
/C4
/C5

43. BEARING DESIGNATIONBEARING DESIGNATION

44. BEARING DESIGNATIONBEARING DESIGNATION

45. TOLERANCETOLERANCE

46. DESIGN CONSIDERATIONDESIGN CONSIDERATION
1. Determine the bearing length by choosing a ratio of l / d.
2. Check the bearing pressure.
3. Assume a lubricant from Table its operating temperature (t0).
This temperature should be between 26.5°C and 60°C with
82°C as a maximum for high temperature installations such
as steam turbines.
4. Determine the operating value of ZN / p ( Sommerfeld No.)
for the assumed bearing temperature and check this value
with corresponding values in Table to determine the
possibility of maintaining fluid film operation.
dl
W
p
*
≈
10*58.14*
2
≈





c
d
p
Zn

47. 5. Assume a clearance ratio c / d from Table.
6. Determine the coefficient of friction (μ) by using the relation.
(k=0.002 for 0.75 - 2.5 l/d ratios)
7. Determine the heat generated by using the relation. (V=
Velocity, W=Load)
8. Determine the heat dissipated by using the relation. (C= Heat
coefficient, A= Area Projected.)
9. Determine the thermal equilibrium to see that the heat
dissipated becomes atleast equal to the heat generated. In
case the heat generated is more than the heat dissipated
then either the bearing is redesigned or it is artificially cooled
by water.
k
c
d
p
Zn
⊕≈ **
10
33
8
µ
VWQg µ≈
( )abd ttACQ −≈ **

48. 10. Temperature of bearing is approximately mid-way between
temperature of atmosphere and temperature of oil film.
( )aab tttt −≈− 0
2
1

49. SAFE DESIGNSAFE DESIGN
1. For well designed bearing, the temperature of the oil film
should not be more than 60°C, otherwise the viscosity of the
oil decreases rapidly and the operation of the bearing is
found to suffer. The temperature of the oil film is often called
as the operating temperature of the bearing.
2. In case the temperature of the oil film is higher, then the
bearing is cooled by circulating water through coils built in
the bearing.
3. The mass of the oil to remove the heat generated at the
bearing may be obtained by equating the heat generated to
the heat taken away by the oil.(m= mass of oil, s=specific
heat of oil(1840-2100J/Kg/degree Celsius, t= difference
between inlet & outlet temperature of oil).
tmsQ ∆≈

52. THANK YOUTHANK YOU