plain bearings

Question 1

name 3 types of radial loads?

Answer 1

stationary
osculating load
reciprocating load

Question 2

stationary load?

Answer 2

present on bearings supporting a horizontal rotor

Question 3

oscillating load?

Answer 3

act on bearings in the crank end of connecting rods in engines.
much smaller clearances

Question 4

advantages of split bearings?

Answer 4

very high load capacity ,high precision ,inexpensive to replace, quick to change out, available in over sizes and undersizes, wide range of material can be used in their construction

Question 5

spherical seated bearings are usually used where?

Answer 5

turbines with a vary long span between bearings

Question 6

what are bushings?

Answer 6

type of plain bearing that has not been split and can handle radial and axial loads

Question 7

advantages of a wrapped bushing?

Answer 7

high fatigue strength
available in pre-finished sizes that are oversized until installed
(should only be used in lightly loaded non critical applications.

Question 8

what is a solid bushing?

Answer 8

bored out of a solid piece of bearing material ( lead,bronze, teflon)

Question 9

advantages of solid bushings?

Answer 9

can be bored out to non standard sizes,easily made from suitable round stock
they can accommodate deep lubricant grooves

Question 10

limitations of solid bushings?

Answer 10

do not have the fatigue strength of wrapped bushings

Question 11

what is a floating bushing?

Answer 11

consists of an outer bushing with a loosely fitted inner bushing

Question 12

applications of water lubricated bushings?

Answer 12

used when water is continuously flushing the bearing and makes it impossible to retain any other lubricant

Question 13

limitations of water lubricated bushings?

Answer 13

only suitable for light loads such as vertical shafts with out side load.

Question 14

pre lubricated bushings are made of?

Answer 14

porous material soaked with lubricant ,lubricant squeezed out under load

Question 15

dry lubricated bushing?

Answer 15

can run dry or with lubricants
available with large range of liner materials
not good for high speeds or heavy loads

Question 16

hydro dynamic bearing is ?

Answer 16

most widely used type of plain bearing
depends on rotation of shaft to drag oil into the loaded area
at normal speed the bearing is supported on a full film of oil

Question 17

What kind of Bearing at start up has virtually no oil in the loaded area which results in dry rubbing friction and boundary lubrication

Answer 17

Hydro dynamic bearings

Question 18

Hydro dynamic bearings are designed to carry any load at?

Answer 18

Very high speeds

Question 19

And unsteady load at high speeds, and develop a condition called what?

Answer 19

oil whirl

Question 20

hydrostatic bearings are found on equipment that operate to?

Answer 20

To slowly to form a Hydro dynamic film or to operate with heavy shock loads. I can breakthrough Hydro dynamic film.

Question 21

What is the minimum speed on a hydrostatic Bearing?

Answer 21

There is no minimum speed load supporting film can be provided at zero speed
Full film of the oil with no dry rub in friction or boundary lubrication on start up

Question 22

Where is an oil left journal Bearing commonly used

Answer 22

Large turbines and compressors this bearing uses hydrostatic pressure to lift the shaft off the Bearing surface before it starts to turn and continues to support it until reaches a speed with the Hydro. Dammit lubrication can take over.

Question 23

Jacking oil must be up to what on a oil lift journal bearing

Answer 23

Must be up to pressure before the shaft just turned, if not, could result in immediate destruction of the Bearing

Question 24

Where is a hybrid bearing used?

Answer 24

Used in situations where there is an imbalance such as an Ecentric weight on the load or that causes radial load to increase as speed increases

Question 25

What does a thrust bearing do?

Answer 25

Function of a thrust bearing us to hold a shaft Axially in the required positions

Question 26

Where are magnetic bearings used?

Answer 26

They are used on large, high-speed, central, fugal compressors

Question 27

What is compressive strength?

Answer 27

Bearing material must be strong enough to support the shops load at maximum operating temperature

Question 28

What is fatigue resistance?

Answer 28

Is the resistance of the bearing material to cracking and flaking by loads that increase and decrease in rapid cycles, fatigue resistance can be increased by keeping the liner material as thin as possible to allow the backing to handle the stress

Question 29

What is high embeddability

Answer 29

Determines how well a material handles contaminants without failing

Question 30

what is deformability?

Answer 30

Allows the material to yield to misalignment or inperfections in the shaft, insurers all parts of the bearing carry a share of the load

Question 31

what is wet ability?

Answer 31

Ability to retain a film of lubricant

Question 32

What is compatibility?

Answer 32

Must not seize or weld to journal under rubbing conditions, such as during start up

Question 33

What is Babbitt?

Answer 33

Babbitt is a white metal alloy is composed of soft alloys, such as tin lead copper and add atimony Lead provides the bearing properties while bronze or copper, provides the strength

Question 34

Where is Teflon used?

Answer 34

It is used for light duty bushings and it is used in bronze matrix for extra strength

Question 35

What are some advantages of Teflon?

Answer 35

It is self lubricating. It is chemically inert It can be used with soft journals

Question 36

What are the disadvantages of Teflon?

Answer 36

It is limited by temperature it emits poisonous gas when burned it absorbs water

Question 37

What is a limitation of aluminum alloys?

Answer 37

They have less embeddability and conformability than babit

Question 38

What is false loading?

Answer 38

A small chip or burr can cause a bearing to support the load on only part of its surface. It results in premature wear

Question 39

What is crush and spread?

Answer 39

crush-crush and spread ensure the insert is mated tightly to the bearing housing bore. Spread is the amount that the insert diameter is wider than the bearing housing diameter

Question 40

Using a vernier, check the journal for taper, and out of round to check for out of round three measurements are taken at what intervals

Answer 40

60 deg intervalls

Question 41

true or false-Plane bearings can be either journal bearings to support radialloads or thrust bearings to sport axial loads

Answer 41

true

Question 42

true or false ?Water lubricated bearings are made of rubber but can be nylon or Teflon.

Answer 42

true

Question 43

true or false--Dry bushings are made of graphite, or Teflon or a bronze matrix containing graphite or Teflon.

Answer 43

true

Question 44

What kind of bearings are found on equipment that operate two slowly to form a Hydro dynamic film

Answer 44

hydrostatic bearings

Question 45

What is another name for the tilting pad thrust bearing?

Answer 45

Kingsbury

Question 46

Where are magnetic bearings used?

Answer 46

large high speed centrifugal compressors

Question 47

Where are gas lubricated bearings used?

Answer 47

They are used for lightly loaded, high-speed applications

Question 48

Use a driver and a ____ when removing a bushing?

Answer 48

adapter