Bearings and Lubrication
Prepared By
Muhammad Nadeem

Agenda
 Bearing Basic
 Bearing Definition
 Main Types of Bearing
 Anti friction Bearing types, Advantage & Disadvantage
 Identify Bearings by Bearing Number-Calculation and
Nomenclature
 Plain Bearing and its Materials
 Plain Bearing types
 Lubrication System

Bearing Basics
 Bearings permit smooth low-friction rotary or linear movement between two
surfaces. Bearings enhance the functionality of machinery and help to save
energy. Bearings do their work silently, in tough environments, hidden in
machinery where we can't see them. Nevertheless, bearings are crucial for the
stable operation of machinery and for ensuring its top performance.
 Bearings are evaluated on the basis of;
 How much load they can carry,
 At what speeds they can carry this load,
 And how long they will serve under the specified conditions.
 And how Reduced friction .
 Ability to withstand impact or harsh environments,

Bearing
 Definition
 Bearing Refers to any kind of support, which is in direct
contact with a moving machine part.
 Bearings are designed to minimize friction, wear and
power loses. Every kind of machine uses bearings of some
kind.
 Main Types of Bearings
 Anti-friction Bearings
 Plain Bearings

Anti-friction Bearings
Antifriction bearings provide rolling contact rather then sliding
contact therefore the total effective contact area is much less in
antifriction bearings as compared to plain bearings. Starting
friction of antifriction bearings is therefore considerably less
than in plain or sleeve bearings.
Types of Anti friction Bearing
1 Ball Bearing
2 Roller Bearing
3 Needle Bearing

Anti- Friction Bearings
 Ball Bearing Types
 Deep Groove Ball Bearing.
 Single Row Angular Contact Ball Bearing.
 Double Row Angular Contact Ball Bearing.
 Ball Thrust Bearing.

Ball Bearing Parts & Construction
 Outer race
 Retainer or cage
 Inner race
 Rolling elements

Anti- friction Bearings
 Roller Bearing Types and parts.
 Cylindrical Roller Bearing
 Spherical Roller Bearing.
 Tapered Roller Bearing
 Needle Roller Bearing
 Roller Thrust Bearing
Outer race
(cup)
Rollers

Advantage & Disadvantage of
Anti-Friction Bearing
Advantage
 Less power demand because of low starting friction
 Less maintenance and lubrication is required.
 Both radial and axial loads can be carried by certain types.
 Higher speed operation
 Ability to perform under adverse condition.
Disadvantage
 More noisy at very high speeds.
 Low resistance to shock loading.
 More initial cost.
 Design of bearing housing is complicated.

How to Identify Bearings by Bearing
Number-Calculation and
Nomenclature

How to Identify Bearings by Bearing
Number-Calculation and Nomenclature

How to Identify Bearings by Bearing Number –
Calculation and Nomenclature

Plain Bearing
 Plain bearings have sliding contact between the shaft and the
bearing surfaces.
 The simplest type of bearing is made by supporting the shaft
directly in a hole in the supporting component as shown in Fig
2, The supporting component is often the casing of the
machine.

Plain Bearings Materials
 Bronze
 Babbitt metal (Tin Alloy)
 Cast iron/steel
 Aluminum alloys

Plain Bearing Types
 Journal Bearing
 Thrust Bearing
 Guide Bearing

Journal Bearing
 The Journal Bearing includes a Babbitt, sleeve and shell
bearing. The journal bearings only for the radial load that is
perpendicular to the shaft, usually because of the downward
load or weight of the shaft

Thrust Bearing.
Purpose of Thrust Bearings
• Absorb axial thrust forces generated by Process differential
pressures on Shaft or Rotor, discharge to suction
• Axially position rotor with respect to stationary parts

Thrust Bearing Construction

Advantages of Plain Bearings
 Lower costs
 Longer fatigue-free service life of their elements.
 Lighter weight.
 Less noisy.
 They require less radial space, since they are built with thin
walls.
 Their installation is simpler.
 Using self-lubricating bearings, lubrication procedures are
not required.
 They allow for higher rotational speeds.
 Greater shock resistance.

Disadvantages of Plain Bearing
 Higher friction during transient processes (especially during
startup).
 They require more axial space.
 The use of friction resistant materials in their manufacturing
is indispensable.
 Greater wear when compared to rolling bearings, since there
is a direct friction between the bush and the shaft

Journal Bearing Damages.
Plain bearings have been used for many years in all types of rotating
machinery and the vast majority gives excellent service over long
periods of time. When, however, they suffer damage the cause
may be vague
Typical Damage Types
1. Scoring Due To Foreign Matter Or ’Dirt’
2. Fatigue Cracking Of Bearing Surface
3. Pivot Fatigue Or Fretting
4. Corrosion
5. Lacquering Due To Oil Breakdown Or Contamination
6. "Black Scab" Or "Wire Wool" Damage

Journal Bearing Damages contd….
1. Scoring Due to Foreign Matter or ’Dirt’
Fig. 1
Material: White metal
Severity: Moderate
Description: Bearing scored and pitted with dirt
Fig. 2
Material: White metal
Severity: Severe
Description: “Holes” caused by dirt particles

Journal Bearing Damages contd….
1. Scoring Due to Foreign Matter or ’Dirt’
Fig. 3
Material: Tin-based white metal
Severity: Severe
Description: Concentric scoring of thrust due to
dirt entering bearing at high speed
Fig. 4
Material: Tin-based white metal
Severity: Moderate
Description: Scoring by dirt entering at start-up
Fig. 5
Material: Tin-based white metal
Severity: Moderate
Description: Surface of pad in Fig. 4 at higher
magnification showing irregular tracks caused
by rolling of shot-blast spherical steel particles

Journal Bearing Damages
Recommended Action:
Bearings in condition shown in Figs 2 & 3 should be scrapped or
relined, and replacement bearings fitted after cleaning journal, oil
ways and filters. Bearings in condition shown in Fig 1, 4, and 5,
should be refitted, after cleaning bearings and journal surfaces,
provided clearance increase due to wear can be tolerated. In all
cases, consideration should be given to improving the level of full-
flow filtration or installing a by-pass centrifugal filter.

Bearing Lubrication.
 Bearings cannot be discussed without considering lubrication.
Lubricant film separates the shaft journal from bearing and thus
reduces friction and prevents the shaft and the bearing from
overheating.
 When the shaft begins to rotate, a wedge of oil is forced under the
journal, lifts it away from the bearings and thus Full-film
lubrication is achieved.
 Both Oil and grease can be used as a lubricant. However grease is
used where the shaft rotates at a very slow rpm.

Lubrication Systems.
1. Manual Lubrication
Manual lubrication requires the use of a portable pump, which
is not part of the machine, and an oil cup or grease fitting.
Tubing or drilled passages carry the lubricant from the fittings
to the friction points. Lubricant is applied by connecting the
pump outlet to the fitting and injecting a specified amount of
lubricant.

Centralized / forced Lubrication Systems
Centralized lubricating systems lubricate all the friction
points from a single pump source. The pump can be manual,
mechanical, or motor operated. Positive pressure controls
the flow rate and also provides a means of indicating correct
operation or malfunction.

Self-lubrication
In this process, the material is inherently self-lubricating or
the mechanism does the work of delivering lubricant to
critical points. Examples of the latter are oil splash systems,
oil slingers, and oil baths.

WHAT IS MIST LUBRICATION
Oil-Mist is centralized lubrication system that continuously
atomizes oil into small particles and then conveys and delivers
the correct amount of the pressurized lubricant to the surfaces
requiring lubrication. Oil mist can be used to continuously
lubricate several different classes of operating or stand-by
equipment in widely dispersed physical locations within the
same facility using only one type of lubricant.
•Oil mist is considered a “best practice” by many companies in
the process industries. Many mist systems are retrofits on
existing oil lubricated applications pumps and motors. Oil mist
was developed in Europe in the early 1900’s to replace grease
and circulating oil systems on high speed spindle bearings.

SCHEMATIC VIEW OF OIL-MIST SYSTEM

ADVANTAGES OF MIST SYSTEMS
 •Bearing failures reduced 50-90%
 •Positive pressure prevents ingression of contamination
 •Lower friction, no oil churning, reduced bearing temperatures
(typically 10°F and often 20°F)
 •Very slight cooling by air
 •Application without contamination in dirty environment
 •Automated system ensures the right amount of lubricant all
the time
 •Rust and corrosion protection of non-running pumps
(maintains an oil fog environment)
 •Elimination of thermal cycling in idle equipment
 •Reduce energy consumption (bearings operate in a thin film of
oil instead of a pool of oil, typically 3 percent)

ADVANTAGES OF MIST SYSTEMS
 •Better lubricant properties, because the oil on the bearings
is always new (not so with closed loop systems)
 •No oil changes, less maintenance
 •Reduction in cooling water usage, elimination of cooling
water in bearing housing
 •Increases safety -- eliminates hand labor next to moving
machines
 •Reduced lubricant consumption (up to 40 percent compared
to sump lubrication)
 •Low maintenance (no moving parts, lubes difficult areas, no
need to check individual housings)

THANKS
Thank you so much for your patience
& kind attention !!!