MODULE 2 (1.3) - BEARING TYPE SELECTION

Question 1

dependent on a number of parameters as laid out by engineering advisory organizations, such as ASM (American Society of Materials) and EDSU (Engineering Sciences Data Unit) (UK)

Answer 1

Selection of Bearing Types

Question 2

also include the following factors: mechanical requirements, environmental conditions and economics

Answer 2

Selection of Bearing Types

Question 3

Rubbing, porous metal, rolling element, oil film

Answer 3

100

Question 4

Porous metal, rolling
element, oil film

Answer 4

1,000

Question 5

Rolling element, oil film

Answer 5

10,000

Question 6

Oil film

Answer 6

100,000

Question 7

an advantage of ball and roller bearings

Answer 7

low starting friction under load

Question 8

usually considered on large, heavy machines such as electric generators at hydroelectirc dams and in utility power plants

Answer 8

Friction and Power Loss

Question 9

speed limits for fluid film bearings are higher than rolling element bearings

Answer 9

Speed

Question 10

rolling element bearings are generally more versatile in being able to carry their fatigue rated load at all speeds with normal lubrication

Answer 10

Load

Question 11

hydrostatic bearings can support enormous structures

Answer 11

Load

Question 12

rolling element bearings have a distinct fatigue life limit which results from the repeated contact stressing of the balls and rollers

Answer 12

Life

Question 13

fluid film bearings provide essentially unlimited life

Answer 13

Life

Question 14

dry and semi lubricated bearings are affected by its wear coeffcient

Answer 14

Life

Question 15

rolling element bearings require only enough lubricant to provide a film coating over the surface roughness of the surfaces

Answer 15

Lubrication

Question 16

rolling element bearings require only enough lubricant to provide a film coating over the surface roughness of the surfaces

Answer 16

Lubrication

Question 17

fluid film bearings (oil) require relatively large quantities of oil to maintain the separating film

Answer 17

Lubrication

Question 18

dry and semi lubricated bearings require smaller space compared to rolling element and fluid film ones

Answer 18

Space Requirement

Question 19

temperature range, moisture, dirt and corrosive atmospheres are the important considerations

Answer 19

Environmental Considerations

Question 20

fluid film bearings generally are limited in temperature range

Answer 20

Environmental Considerations

Question 21

rolling element bearings can be adapted to meet wide ranging environmental demands

Answer 21

Environmental Considerations

Question 22

capital costs and maintenance/replacement costs are the usual consideration

Answer 22

Economics

Question 23

dry and semi lubricated bearings have the lowest costs and are usually mass produced

Answer 23

Economics

Question 24

rolling element bearings are a step higher in cost, while fluid film bearings are the expensive ones

Answer 24

Economics

Question 25

fluid film bearings require little or no maintenance, while rolling element bearings require occasional attention for a change of oil, new filter or general cleaning

Answer 25

Economics