1. Chapter 9 Bearings Topics Introduction to bearings Types of bearings
MECH 1200
Chapter 9 Bearings
Topics
Introduction to bearings
Types of bearings
Plain bearings
Antifriction bearings
Axial and Radial Loads
Questions

2. Introduction Purpose of bearings: Support loads Reduce friction
MECH 1200
Purpose of bearings:
Support loads
Reduce friction
The PV factor:
PV factor refers to the Pressure and Velocity ratings of the bearing.
Pressure is the load on the bearing in pounds divided by the projected area in square inches.
Velocity is the surface velocity of the shaft.

3. Plain (Journal) Bearings Antifriction (rolling) Bearings
MECH 1200
Some types of Bearings
Plain (Journal) Bearings
Antifriction (rolling) Bearings
Solid
Deep Groove Ball Bearing
Split
Angular Contact Ball Bearings
Self Aligning Ball Bearing
Pure Thrust Ball Bearing
Cylindrical Roller Bearing
Spherical Roller Bearing
Tapered Roller Bearing
Needle Roller Bearing

4. Plain Bearings Other names: journal, friction, or sleeve bearings
MECH 1200
Other names: journal, friction, or sleeve bearings
They work by sliding action in contrast to rolling action of the antifriction bearings.
Types: Solid and split types
Advantages:
Can handle high loads
Quite operation: because no rolling elements exist.
Require less space than antifriction bearings.
Low cost
Disadvantages:
Limited to low speed applications
Require precise alignment
Lubrication is essential for their performance.

5. Antifriction Bearings
MECH 1200
Antifriction Bearings
Parts: inner ring, outer ring, rolling element, and retainer.
They work by rolling action.
Advantages:
Higher efficiency than plain bearings
Can handle high speeds
Can tolerate misalignment better than journal bearings
Bearing Types by rolling elements:
Ball bearings
Cylindrical Roller Bearings
Taper Roller Bearings
Spherical Roller Bearings
Point contact vs line contact:
Ball bearings make a point contact with the race, but cylindrical bearings make line contact, therefore ball bearings are more efficient, but cylindrical roller bearings can handle higher loads.
Spherical roller
Taper roller
Ball
Cylindrical roller

6. Axial and Radial Loads Radial load Radial load Axial load
MECH 1200
Some bearings are designed to handle only radial loads, others are designed to handle axial loads, others are designed to handle a combination of both.
Radial load
Radial load
Axial load
Axial (thrust) load

7. Light axial (thrust) load
Ball Bearings
MECH 1200
Light radial load
Moderate radial load
Light axial load
Light axial (thrust) load
Self-aligning double row ball bearing
Deep groove ball bearing
Moderate radial load
Light radial load
High axial load
Angular contact ball bearing
High axial load
Single acting thrust ball bearing

8. Other Antifriction Bearings
MECH 1200
High radial load
High radial load
Low axial load
Moderate axial load
Cylindrical roller bearing
Spherical roller bearing
Tapered roller bearing
High radial load
High axial load
Needle roller bearing

9. Questions What other names are plain bearings called?
MECH 1200
What other names are plain bearings called?
Other names are journal, friction, or sleeve bearing
Why cylindrical roller bearings can handle more radial load than ball bearings can?
Because the cylindrical roller element makes a line contact with the rings, but the ball bearing makes a point contact, therefore a higher pressure is exerted on the ball element from the load.
Which of the two bearings mentioned above is more efficient?
Ball bearings because of the less contact area, and less friction.

10. What type of bearing is shown in the figure below?
MECH 1200
What type of bearing is shown in the figure below?
Journal bearing
Double row deep groove ball bearing
Spherical roller bearing
Self aligning double row ball bearing
Tapered roller bearing
The bearing is designed to carry:
High radial loads
High axial loads
Moderate radial but high axial loads
High radial and axial loads
It only can carry light loads

11. These bearings shown above are:
MECH 1200
Determine if each of the following bearings is loaded correctly or not:
These bearings shown above are:
Friction bearings
Journal bearings
Plain bearings
Antifriction bearings
correct
Incorrect
Incorrect
correct
Incorrect

12. Do the student exercise on page 235 of the text.
MECH 1200
Homework
Do the student exercise on page 235 of the text.
Answer questions 1,2,34,8,10, and 14 on page 236.