6.8

Question 1

What does a bearing do ?

Answer 1

Constrains relative motion to Desired motion and reduces friction between moving parts.

Question 2

What does the design of a bearing provide ?

Answer 2

Provides linear movement / rotation around fixed axis

Question 3

What is the role of gears ?

Answer 3

Transmits power, change drive directions and increases / decreases rotational speed.

Question 4

What’s the two major groups of bearings ?

Answer 4

1. Plain - made up of a plain cylinder or flat washer
   2.Rolling - Made up of rolling components

Question 5

What two good characteristics does bearings have ?

Answer 5

1. Made from strong material
2. Provides Quiet and efficient operation

Question 6

What’s the two forces acting upon a bearing ?

Answer 6

1. Axial
2. Radial
   ( bearing can have combo of both )

Question 7

What distributes lubricant over all of the bearing ?

Answer 7

Oil grooves/wells

Question 8

What are synthetic bearings lubricated with ?

Answer 8

Water, whicch also acts as coolant

Question 9

With sliding bearings, why is grease lube used ?

Answer 9

Used on stressed bearings to with large bearing play.

Question 10

What loads does plain bearings take ?

Answer 10

Radial ( journal )

Question 11

When are plain bearings used ?

Answer 11

When load is light a motion is continuous.

Question 12

What’s pivot ( axial ) bearings used for ?

Answer 12

Longitudinal forces

Question 13

What’s 3 advantages of roller and ball bearings ?

Answer 13

1. Almost eliminate all friction
2. Carry heavy loads
3. Don’t heat as much as plain bearings

Question 14

What the 5 types of anti-friction bearings ?

Answer 14

1. Tapered
2. Ball
3. Needle
4. Cylindrical
5. Spherical

Question 15

What separates the different raceways ?

Answer 15

Cage

Question 16

What’s the raceways made from on anti-friction bearing ?

Answer 16

1. Chromium steel
2. Chromium - nickel steel
   ( tracks are polished )

Question 17

What is the distinction between ball bearings and roller bearings ?

Answer 17

Ball bearings - low starting resistants, and high rotational speed.
Roller bearings - are used if stress is too much for ball bearings

Question 18

What are the major components of ball bearing ?

Answer 18

1. Outer ring
2. Inner ring
3. Rolling elements
4. Retrainer

Question 19

What’s the shields and sealants inside the races used for ?

Answer 19

To retain lubricant and protect bearing from contamination.
( races can be machined externally or internally to make them self angling )

Question 20

What are ball bearings used for ?

Answer 20

Accessory drives, gearings
( anywhere narrow bearing is required )

Question 21

What load is ball bearings poor at withstanding due to their point contact

Answer 21

Oscillating loads.

Question 22

When is cylindrical bearings commonly used ?

Answer 22

Non-locating positions

Question 23

What two types of bearings are placed at the end of shaft ?

Answer 23

1. Locating (fixed)
2. Non-locating (floats)

Question 24

What does the cylindrical bearings line contact with races allow it to do over ball bearings ?

Answer 24

Carry more radial loads.

Question 25

Why does the cylindrical bearing have lower lad capacity ?

Answer 25

Has heavier cage and few rollers in order to retain the rollers

Question 26

What properties does a needles bearings long thin rollers give it ?

Answer 26

Very high radial load capacity

Question 27

True or false, spherical roller bearings are self aligning ?

Answer 27

True - self aligning allows it to make minor angle adjustments between shaft and housing.

Question 28

What causes the skidding of rollers in a spherical roller bearing ?

Answer 28

Rolling motion only occurs in two contact points on each roller

Question 29

What load does a spherical roller bearing take ?

Answer 29

Radial - but stress isn’t evenly distributed when under heavy loads .

Question 30

When is a spherical bearing best suited to be used?

Answer 30

1. Risk of misalignment while assembly 2. Where speed isn’t exacting

Question 31

4 Advantage of tapered roller bearing ?

Answer 31

1. Less vulnerable to contaminants due to natural pumping action 2. Low fiction 3. Loner service life 4. Can take radial and axial loads

Question 32

2 Advantages of air bearings ?

Answer 32

1. Zero- friction 2. Don’t need lubricant and don’t wear

Question 33

How’s air bearings fluid film created ?

Answer 33

By applying flow of air through bearing face and into bearing gap.

Question 34

What 3 bearings are designed purely for thrust loads ?

Answer 34

1. Roller 2. Ball 3. Needle

Question 35

How is a thrust bearing often mounted ?

Answer 35

Vertically - this supports heavy machinery. - used on propellers as well.

Question 36

What loads do thrust bearings take ?

Answer 36

Axial loads, Limited radial loads (They have high load capacity)

Question 37

If radial load is expected, what is placed next to the thrust bearing ?

Answer 37

Another bearing

Question 38

What is the function a bearing ?

Answer 38

Reducer friction between moving parts