Bearings and seals 150402b Flashcards Preview

yr 4 machinist > Bearings and seals 150402b > Flashcards

Flashcards in Bearings and seals 150402b Deck (61):
1

when compared to roller bearings , plain bearings are

  1. noisier
  2. more expensive
  3. easier to maintain
  4. quieter

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quieter

when compared to roller bearings, plain bearings require less space, operate more quietly cost less and are more rigid

2

the bearing material which is inexpensive but requires generous lubrication is

  1. bronze
  2. sintered bronze
  3. cast iron
  4. nylon

cast iron

3

the two halves of a split bearing are held in place by

  1. press fit
  2. adhesive
  3. a key
  4. a locking tab or dowel

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a locking tab or dowel

4

the anti friction bearings that accomodates both radial and bidirectional thrust loads is the ?

  1. single row deep groove bearing
  2. tapered roller bearing
  3. needle roller bearing
  4. cylindrical roller thrust bearing

single row deep groove bearing

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5

the roller bearing that must be used in pairs is the ?

  1. single row deep groovebearing
  2. double row tapered roller bearing
  3. double row spherical bearing
  4. single row angular contact bearing

single row angular contact bearing

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6

the roller bearing that can accomodate up to 2 1/2 degrees of misalighnment is the 

  1. single row deep groove bearing
  2. internally self aligning bearing
  3. externally self aligning bearing
  4. double row sperical bearing

double row spherical bearing

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7

the bearing that takes up the least radial space is the?

  1. double row tapered bearing
  2. needle roller bearing
  3. cylindrical roller bearing
  4. double row angular contact bearing

needle roller bearing

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8

what is the upper limit for the shaft bearing seat for a 40 mmbearing having a class h5 fit?

  1. 1.5748
  2. 1.5744
  3. 1.5746
  4. 1.5742

  1. consult table of fits 
  2. consult table of tolerances

9

the type of seal used for static assemblies only is a 

  1. gasket
  2. o ring
  3. u ring
  4. lip seal?

gasket

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10

the width of a o ring groove should be approximately?

  1. equal to the width of the o ring
  2. 80% of the width of the o ring
  3. 70% of the width of the o ring
  4. 150% of the width of the o ring

150% of the width of the o ring

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11

a u ring can be held in place with a ?

  1. support ring
  2. adhesive
  3. sealant
  4. anti extrusion ring

support ring

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12

what is another name for a solid plain bearing ?

bushing

13

what are the 4 types of plain bearings?

  1. soilid plain often called bushings
  2. radial bearings
  3. thrust bearings
  4. guide of slipper bearings

14

plain bearings require _____ space

operate more quietly cost____ and are more rigid

plain bearings require Less space

operate more quietly cost less and are more rigid

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15

the round part of a shaft  that rides in a plain bearing is called a _____ and plain bearings for rotating shafts are called journal bearings

he round part of a shaft  that rides in a plain bearing is called a JOURNAL and plain bearings for rotating shafts are called journal bearings

16

______ bearings support rotating shafts.______bearings support  axial loads and _____ quide  or slipper bearings quide moving parts in a straight line

radial bearings support rotating shafts.thrust bearings support  axial loads and  quide  or slipper bearings quide moving parts in a straight line

17

solid bearings are most likely made out of what materials?

  1. bronze
  2. sintered bronze
  3. cast iron
  4. plasic

18

why is bronze used for solid plain bushings?

  1. easy to use
  2. wont gaull
  3. wont seize on steel journals
  4. best for meadium speeds and loads

19

anothe rname for  sintered bronze is?

oilite

20

why are sintered bronze bearings commonly called oilite bushings?

because they are porous so they can be soaked in oil. the oil contentent is usually between 3 and 30%

21

what are sintered bronze bearings used?

they are used where its  not practical to supply lubricant  from the outside

22

cast iron bearings are used for _____ speeds {130 feet per minute}

and ________loads they are inexpensive but require lots of lubrication

low speeds and light loads

23

why is it becoming encreasenly common to make bearings out of plastic?

  1. resist corrosion
  2. easy to machine
  3. quiet 
  4. require little lubrication

24

why is nylon used to make bearings?

used in small bearings for light loads

25

why use teflon to make bearings?

extremely slippery and needs no lubricationbut is only good for low loads bearing and its expensive

26

what advantage does using rubber have to make bearings?

its used when bearing is exposed to water. it helps dampen vibration and compestes for small degrees of misalignment

27

what are some of the advantages of using a split bearing?

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  1. easily replaced by removing the bearing cap
  2. clearence on some bearing can be ajusted by adding shim

28

the two broad catagoriesof split bearings are?

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  1. thickwall and thin wall

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29

what is this and what is its function?

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this is known as a thrust bearing it is used to prevent a shaft from moving under end thrust.. thrust bearimgs consist of one or more support surfaces perpendicular to the axis of the shaft

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30

what is another name for a tapered land thrust bearing? and why is it better than a flat plate thrust bearing?

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profiles pad thrust bearing

 provides greater load capacity because if its superior hydronamic lubrication

31

what are the 5 types of ball bearings?

  1. single row deep groove
  2. double row deep groove
  3. single row angular contact
  4. double row angular contact
  5. self aligning
  6. just remember single double single double self aligning

32

with anti friction bearings the rollers can be r____ b______

shaped or T_________ and are hardend and ground to tollerances of .0001. they are normally  sealed 

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with anti friction bearings the rollers can be round barrel

shaped or Tapered and are hardend and ground to tollerances of .0001. they are normally  sealed 

33

what is the type of bearing called? and what are its characteristics?

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this is a single row deep groove bearing

  • meant for radial loads
  • moderate thrust
  • not self aligning so shaft and housing bore must be aligned to 10 minutes of  a degree

34

what type of bearing is this and what are its characteristics?

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double row deep groove bearing

  • has filling slots 
  • has been replaced by the double row angular contact bearing

35

what kind of bearing is this and what are its characteristics?

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single row angular contact

  • these are used in pairs opposite each other
  • they only tolerate a small amount of misalignment

36

what kind of bearing is this and what are its characteristics?

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double row angular contact

  • meant for heavy radial and axial loads 
  • can take axial load in both directions
  • slow speed rating
  • no misalignment 

37

what kind of bearing is this and what are its characteristics?

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self aligning

  • used when shaft is to run at high speeds with extreme accuracy

38

self aligning internal bearing tolerates up to how many degrees of misalignment?

1.5

39

 a self aligning external bearing tolerates up to how many degrees of misalignment?

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2 degrees

40

whay do roller bearings support a much higher radial load than ball bearings?

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they have line contact while bearings have point contact

41

what are the four main types of roller bearing?

hint

  1. c
  2. single and d
  3. t
  4. n

  1. cylindrical
  2. single and double row sperical
  3. tapered
  4. needle

42

what type of roller bearing are these?

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cylindrical

43

what type of bearings are these? and whats the allowable misalignment?

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these are single row and doible row spherical bearings. as you can see they are barrel shaped which spreads the load over a larger  area.

they can have up to 2.5 degrees misalignment

44

what type of bearings are these?

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tapered roller bearings

45

tapered roller bearings are to be used in __________to accomodate re______ loads and to prevent separation of the bearing. they run at 2/__ the speed of comparable deep groove ball bearings tapered roller bearings tolerate only ____ minutes of misalignment

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tapered roller bearings are to be used in  pairs to accomodate reverse loads and to prevent separation of the bearing. they run at 2/3 the speed of comparable deep groove ball bearings tapered roller bearings tolerate only 3 minutes of misalignment

46

what kind of bearing roller is this?

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single row tapered

47

what kind of bearing set up is this?

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double row cup and cone tapered roller bearing

48

what kind of bearing are these?

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needle roller bearings

  • the first two with no inner ring are good for areas wheere you have no space as the bearings ride on the shaft. this is why you must have hardend shaft they also must be run slower

49

what kind of bearings are these?

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thrust bearings

50

what kind of bearing is this?

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double direction ball thrust bearing

51

what am i looking at?

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this is the correct way to install a bearing

52

a good rule of thumb is that the diameter changes _______ an inch per inch of diameter for every 15 degrees of temperature change

.0001

53

what is the purpose of a seal?

seals are used to keep lubricant in and unwanted contaminants out

54

what are the four main types of seals?

hint

  1. g
  2. o
  3. u
  4. l

  1. gaskets
  2. o rings
  3. u section rings
  4. lip seals

55

gaskets 

gaskets are meant for static assemblies. this is to say the gasket is placed between two mating surfaces that are then boltedtogether s o they cant move.  what are gaskets made of?

simple gaskets for low to medium pressure are made of cork  cellulose(paper) and rubber like compounds called elastomers

gaskets  for high pressure  are made of materials like lead , copper brass monel.

for very high pressure applications they are made of stainless steel

56

what are the gasket styles?

  1. flat face
  2. tongue and groove
  3. male and female

the quality of the seal can sometimes be improved by using a sealant  the sealant can be hardening or non hardening

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57

never put excessive pressure on an o ring or this will happen.

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58

your prime responsiblity is to machine the groove for the o ring .the groove can either the id of the bore or the od of the shaft. what should the clearance be between>

the clearance between the grrove should be between .002 to .010 the width should be 1.5 x the width

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59

another name for a u-ring is called?

what are they usually used in?

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  1. u-cup
  2. used in hydrolic cylinders

60

u-rings  are meant to resist pressure in____ direction only and are most comminly used in __________. sometimes a ______ ring is needed to hold the u ring in position.and for high pressure applications an anti extrusion ring is placed behind the u ring to reinforce it.

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u-rings  are meant to resist pressure in one direction only and are most comminly used in hydrolic cylinders. sometimes a support ring is needed to hold the u ring in position.and for high pressure applications an anti extrusion ring is placed behind the u ring to reinforce it.

61

lip seals are used on ?

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shafts preferably on shafts thats are ground or have a micro finish of .8 microns