Print this page Salient Features of Bearing Lubrication
A. Bhatia, B.E.
Course Outline
Improper lubrication
accounts for up to 50% of bearing failures!
The purpose of this 2-hour course is to help you to recognize the relationship
of bearings and proper lubrication. Selection of the proper lubricant is an
important design function in the use of bearings, since lubricant affects bearing
life and operation.
This course material is based entirely on the US Army Corps of Engineers document
EM 1110-2-1424, "Lubricants and Hydraulic Fluids" and covers Chapter
10 "Bearings".
The course includes a multiple-choice quiz at the end, which is designed to
enhance the understanding of the course materials.
At the conclusion of this course, the readers will:
- Learn the various types of plain and rolling contact bearings;
- Understand the merits and limitations of using mineral oil v/s grease lubrication;
- Learn the methods of liquid lubricant supply;
- Learn the key parameters for choosing between grease and oil lubrication;
- Understand the effect of method of application and environmental conditions on choice of suitable grade of grease; and
- Learn how to
calculate bearing lubrication interval.
This course is aimed at students, mechanical and process engineers, O & M professionals, H &S professionals, machinery specialists, energy auditors, plant layout professionals and general audience.
Course Introduction
The major functions
of lubrication in bearing application are:
1) to minimize friction at points of contact within the bearing
2) to protect the precision finishes on bearing surfaces from becoming corroded
3) to dissipate heat generated within the bearing
4) to remove or prevent the entry of foreign matter within the bearing
Bearing applications have wide variations of load, speed, temperature and environment,
and proper lubrication calls for matching the oil/grease precisely to the bearing
application.
In this course, you will learn the various types and applications of bearings
and understand different lubrication methods and applications to reduce friction.
Course Content
In this course, you are required to study US Army Corps of Engineers document EM 1110-2-1424, "Lubricants and Hydraulic Fluids":
EM 1110-2-1424, "Lubricants and Hydraulic Fluids" - Chapter 10 "Bearings"
You need to open or download above documents to study this course.
Course Summary
Two basic types
of lubricants-oils and greases-are used with anti-friction bearings. Each has
its advantages and limitations. The applications of both are summarized below:
Oil
Oil retains its physical characteristics over a wide range of temperatures,
making it ideal for high speed and high temperature applications. The quantity
of oil supplied to the bearing may be controlled accurately allowing for better
circulation, cleansing and cooling. Note the following advantages:
1) Better for high speed operation.
2) Easier dispersion over bearing surfaces.
3) Diffuses heat quicker because of viscosity
4) Easier to handle and control amount of lubricant reaching the bearing
5) Variety of ways to deliver oil (drip, wick, circulation, batch, air-oil mist)
make it easier to introduce into bearing
6) Easier to keep clean for recirculation systems
7) Easily controlled lubrication. Carries away moisture and particulate matter.
Grease
As a thicker substance, grease can seal a bearing better than oil, while allowing
seal design simplification. It can be confined easily in the bearing housing,
and permits pre-lubrication of sealed or shielded bearings. A No. 1 or a No.
2 grease is generally satisfactory for operation at ordinary temperatures; the
lighter grease should be used for operation at high speed or at low room temperature.
Note the following key advantages:
1) Clings to surfaces better. Is squeezed out of roller path to lesser extent
2) Easier to retain in bearing.
3) Lubricant loss is lower than oil loss.
4) Generally requires less frequent lubrication
5) Lasts longer and protects better than oil
6) Acts as an efficient bearing sealant. Allows seal design simplification
7) Easily confined in housing, an important plus in food, textile and chemical
industries.
The value and importance of using the right bearing lubrication should not be
underestimated. Before selecting a suitable method remember the 3 key points:
1) Determine the maximum load for the bearing. This is important both vertically
and horizontally
2) Determine the minimum and maximum running speeds for the bearing. This will
help determine the correct lubricant and bearing for the application.
3) Determine all possible environmental conditions to which the bearing will
be exposed. Very hot or cold environments often require varied bearing specifications.
This may, in turn,
change the type of lubricant and relubrication requirements as well.
For specific recommendations, always consult the manufacturer's manual.
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
