1. Bearings, Lubricants and Couplings
Chapter 16
Bearings, Lubricants and Couplings

2. Bearings Used to reduce friction between two surfaces
Different designs to accommodate rotational or linear motion
Different designs for different load directions

3. Bearing Loads Radial Load
Load acting perpendicular to the axis of the shaft

4. Thrust Load
Load parallel to the axis of the shaft
Combination Load
Both radial and thrust loads applied to the bearing

5. 2 categories of bearings
Plain bearings
Rolling element bearings

6. Plain Bearings Operation is based on sliding action between 2 parts
Bearing will have a press fit into the housing and a clearance fit to the shaft
No moving parts
Also called sleeve bearings, journal bearings and bushings

8. Plain bearing materials
Bronze-needs to be lubricated
Phosphor bronze-oil impregnated
Various plastics
These materials allow low friction movement

9. Rolling Element Bearings
Have moving parts to reduce friction
Several types
Ball Bearings
Most common
High speed applications

11. Roller Bearings
Cylindrical roller element
Higher load capacity, lower speeds
Several styles

12. Bearing Symbols Bearings are purchased parts
Different symbols used depending on drawing type
Schematic symbols used for machine layout drawings

13. 3D models of products using bearings can use a simplified 3D model of any bearings in the product

14. Machine Layout Drawing

15. Lubrication Roller bearings require lubrication
Too much can result in high temps and bearing failure
Too little and friction will cause heat and failure
Lubricants
Oil-slippery hydrocarbon liquids
Grease-semisolid, a fluid lubricant with a thickening agent

16. Assets of Oil
Easy to control volume
Travels well
Carry away heat
Carry away products of wear
Assets of Grease
Stays put
Less maintenance
Seals out moisture

17. Couplings
Devices used to join two shafts together
3 categories

18. 1. Solid Couplings
Used only when driving and driven shafts are mounted to a solid base (can’t move around)

19. 2. Flexible Couplings Compensate for unintentional misalignment
Prevent shock from being transferred between the shafts

21. 3. Universal Couplings
Used when shafts are at an angle to each other (angle can change)
Also called universal joints

22. Flexible Shafts Transmits power at angles and around corners
Helically wound wire designed to transmit rotary motion

23. TEST REVIEW
Mechanism
Linkage
Cam
Cam follower
Bearings
Plain bearing
Roller bearings
Ball bearings
Couplings
Flexible couplings
Universal couplings

24. Gear types and orientation of their shafts:
Spur
Bevel
Worm
Rack and pinion
Gear train problem
Plastic gear advantages (3)
Bearing loads list and explain
Assets of oil
Assets of grease