Design of machine Elements- Rolling Contact Bearing- Theory and solved problems (PSGDB followed)

1. DESIGN OF MACHINE ELEMENTS
Rolling Contact Bearing
DEVAN P D
Assistant Professor
Kumaraguru College of Technology

2. Rolling Contact Bearings
•Sliding bearing starts from rest with practically metal-to-metal contact and has a high
coefficient of friction.
•Rolling contact bearing has a low starting friction.
•Due to this low friction it is called as antifriction bearings.
•These bearings can take radial load, thrust load and combination of thrust and radial
load

3. Classifications

5. Nomenclature

6. Bearing Selection
Bearing Life:
•Life of bearing is expressed in terms of million rev or hours at constant
speed that the bearing runs before the first evidence of crack developed.
Rating life:
•Rating life is defined as the life of a group of apparently identical ball or
roller bearings, in number of revolutions or hours, rotating at a given
speed, so that 90% of the bearings will complete or exceed before any
indication of failure occur.

7. Reliability

8. Static Load Carrying Capacity :
The static load which corresponds to a total permanent deformation of
balls and races, at the most heavily stressed point of contact, equal to
0.0001 of the ball diameter.
Dynamic Load Capacity:
The life of an individual ball bearing is defined as the number of
revolutions (or hours of service at some given constant speed), which the
bearing runs before the first evidence of fatigue crack in balls or races.

9. Equivalent Dynamic Load

10. Load Life Relationship

11. Cubic Mean Load

12. Problem 1:

14. Problem 2:

17. Problem 3: