Operational Clearances for Bearings

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deevamp40 Active Contributor Join Date: Sep 2009 Posts: 23	Operational Clearances for Bearings 12/17/2009 3:25 AM
	Hai Tech Savvys; I was going through the standards of bearings regarding the design of certain mechanisms (conveyor mechanisms) used in a system design process. My boss asked me to put "operational clearence" for the bearings which are mounted on a shaft.I got confused.I couldn't find a thing abt that. How could a Bearing work if there is a clearence in it?. Here the fit used is "precision fit".If the clearence exists, Where are they used & in what types of fits are they used?
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#3 "Re: Operational Clearances for Bearings" by isloorkar on 12/22/2009 9:12 AM (score 2)

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#1 "Re: Operational Clearences for bearings?" by Anonymous Poster on 12/17/2009 9:10 AM (score 1)

Anonymous Poster	#1 Re: Operational Clearences for bearings? 12/17/2009 9:10 AM
	Go to any of the standard manufacturer's site. SKF, FAG, Timken all have it. Try to find the catalogue of the roller bearing of the type you want - BB, DGBB, SRB, CRB, TRB,... based on our applications and load type - shock, intermittent, heavy shock,... there is a page where they give the recommended fits and end-plays. I can tell you the page number Let Us say SKF general catalogue it is on Page 137 , Page 165 onwards (for type of fit) etc. Similar pages i can search out from other catalogues too. But What I will advice you is to get hold of one of these and go through- there are extensive explanations, reasons, calculations etc. This is catalogue 5003E of SKF, I don't know it is on soft copy or not. But has a lot of info. FAG has one called bearing Mounting design. Timken catalogue has an Engg section of about 200 pages, this aspect is on A73 and so on. But that is not important, You have to know your load and design the housing, shafts, preload and endplay. Else if you are in a mass production, the bearing manufacturer will be more than ready to help you.
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Ed Weldon Guru Join Date: Oct 2008 Location: I'm outa here Posts: 1924 Good Answers: 196	#2 Re: Operational Clearances for Bearings 12/18/2009 12:31 AM
	Your boss sounds like he is reacting to past experiences, perhaps painful, that were cause by bearing failures of some kind, and that this is an area of technology where he has little technical knowledge. Guest in answer #1 begins to explore this complex subject with good comments. You need to learn more about bearings and their "maintenance and installation". These are key words for antifriction bearing manufacturers. Most publish well written and illustrated literature on this exact subject and have this information available on the internet. If you are dealing with conveyors and other ordinary materials handling systems most of the bearings you will encounter will be antifriction bearings of which the largest proportion is ordinary grease lubricated ball bearings. Plain or sleeve bearings may be present in some equipment especially very large and very small machinery and are usually engineered for the specific application. Here you are best advised to follow the equipment manufacturer's recommendations. In the case of old equipment where the manufacturer is not a good information source you are best advised to follow the advice of an experienced machinery mechanic or millwright as knowledge of such bearings is a basic part of their trade. Ed Weldon
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isloorkar

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Join Date: Jan 2008

Location: Pune, India

Posts: 59

Good Answers: 4

Re: Operational Clearances for Bearings

12/22/2009 9:12 AM

22.12.09

Honestly, I copied and pasted the table below. You may find it useful.

Tolerance Code

over 3 upto 6

over 6 upto 10

over 10 upto 18

over 18 upto 30

over 30 upto 50

over 50 upto 80

over 80 upto 120

over 120 upto 180

over 180 upto 250

over 250 upto 315

over 315 upto 400

over 400

upto 500

g 6

Crane runner wheels ; self-aligning spherical bearings.

Vibratory screens ; self-aligning spherical roller bearings as floating bearings.

g 6

-4

-12

-5

-14

-6

-17

-7

-20

-9

-25

-10

-29

-12

-34

-14

-39

-15

-44

-17

-49

-18

-54

-20

-60

h 5

-5

-6

-8

-9

-11

-13

-15

-18

-20

-23

-25

-27

h 6

Automobile front wheels ; angular contact ball bearings in inner position, taper roller bearings in outer position (adjustment over inner ring).

Automobile gears : Deep groove ball bearings.

Rolling mills flywheels : Barrel type roller bearings and self aligning spherical roller bearings (stationery inner ring).

Closed bearings for rope sheaves.

Vibratory screens : double row self aligning spherical roller bearings as floating

h 6

-8

-9

-11

-13

-16

-19

-22

-25

-29

-32

-36

-40

j 5

Automobile pinion shafts : Double row angular contact ball bearings (see k 5)

Small motors : Deep groove ball bearings 6200-6208.

Generators : Magneto type bearings.

Machine tool spindles : Deep groove and angular contact ball bearings.

Spindles for woodworking machines: Deep groove ball bearings.

Rotors of rotary piston blowers : Double row angular contact ball bearings.

Shaft seatings for thrust bearings.

j 5

-1

-12

-3

-4

-5

-7

-9

-11

-13

-16

-18

-20

j 6

Automobile front wheels : Angular contact ball bearings and taper roller bearings in outer position (adjustment over inner ring).

Automobile gears : Deep groove ball bearings.

Rail vehicles : Double row self aligning spherical roller bearings for pit tubs

j 6

+ 7

-1

+ 7

-2

-3

-4

+11

-5

+12

-7

+13

-9

+14

-11

+16

-13

+16

-16

+18

-18

+20

-20

k 5

Automobile pinion shafts : Double row angular contact ball bearings (under certain conditions ) (see j 5).

Electric motors : Deep groove ball bearings above 6208 and 6306, cylindrical roller bearings with bore diameters up to 60 mm.

Machine tool spindles : Taper and cylindrical roller bearings.

Fans : Deep groove ball bearings.

k 5

+11

+13

+15

+18

+21

+24

+27

+29

+32

k 6

Light gasoline engines, crankshafts, gears : Deep groove ball bearings.

Automobile pinion shafts, spiral drive gear : Taper roller bearings.

rope sheaves : Cylindrical roller bearings with stationery inner ring.

Shipbuilding : ships propellor thrust blocks : Double row self aligning spherical roller bearings.

Vibratory screens, fixed bearings : Double row self aligning spherical roller bearings.

k 6

+10

+12

+15

+18

+21

+25

+ 3

28 +

+ 3

+ 33

+ 36

+40

+45

m 5

Electric motors : Cylindrical roller bearings and double row self aligning spherical roller bearings, bore diameters over 60 mm.

Heavy machine tool spindles : Taper roller bearings and cylindrical roller bearings.

High speed fans, rope winding drums : Cylindrical roller bearings.

m 5

+12

+15

+17

+20

+24

+11

+28

+13

+33

+15

+37

+17

+43

+20

+ 46

+21

+ 50

+ 23

Tolerance Code

over 3 upto 6

over 6 upto 10

over 10 upto 18

over 18 upto 30

over 30 upto 50

over 50 upto 80

over 80 upto 120

over 120 upto 180

over 180 upto 250

over 250 upto 315

over 315 upto 400

over 400

upto 500

m 6

Medium gasoline and light Diesel engines, crankshaft : Deep groove ball bearings.

Crane runner wheels and rope sheaves : Cylindrical roller bearings.

Electric motors : Cylindrical roller bearings and double row self aligning spherical roller bearings, bore diameter over 60 mm.

Rolling mill gear units : Double row self aligning spherical roller bearings.

Axle boxes for rail vehicles : Cylindrical roller bearings and double row self aligning spherical roller bearings, diameter of bore up to 100 mm.

m 6

+12

+15

+18

+21

+25

+30

+11

+35

+13

+40

+15

+46

+17

+52

+20

+57

+21

+63

+23

n 6

Medium and heavy Diesel engines, crankshaft : Cylindrical roller bearings, double row self aligning spherical roller bearings and single row self aligning barrel roller bearing.

Vibrating screens : Cylindrical roller bearings.

Electric rail traction motors : Cylindrical roller bearings and double row self aligning spherical roller bearings over 50 mm dia bore.

Axle boxes for rail vehicles : Cylindrical roller bearings and double row self aligning spherical roller bearings, diameter of bore over 100 mm.

+16

+19

+10

+23

+12

+28

+15

+33

+17

+39

+20

+45

+23

+52

+27

+60

+31

+66

+34

+73

+37

+80

+40

p 6

Supporting rollers of rotary kilns : Cylindrical rollers bearings.

Frame saws, crank pins : Double row self aligning spherical roller bearings.

Locomotive coupling rods : Cylindrical roller bearings and double row self aligning spherical roller bearings, axle boxes of rail vehicles from 150 mm dia bore on, Rolling mills, cold and hot rolls : Cylindrical roller bearings.

p 6

+ 20

+ 12

+ 24

+ 15

+ 29

+18

+ 35

+22

+ 42

+26

+ 51

+ 32

+ 59

+ 37

+ 68

+ 43

+ 79

+ 50

+ 88

+ 56

+ 98

+ 62

+ 108

+ 68

h 7

Ring row mills and beater mills : Double row self aligning spherical roller bearings with withdrawal sleeve.

Frame saw, crank pins " Double row self aligning spherical roller bearings with withdrawal sleeve.

Locomotive crank pins : Double row self aligning spherical roller bearings with withdrawal sleeve.

Rolling mills, roll journals : Double row self aligning spherical roller bearings with withdrawal sleeve.

h 7

-12

-15

-18

-21

-25

-30

-35

-40

-46

-52

-57

-63

h 9

Rope sheaves : Double row self aligning spherical roller bearings with withdrawal sleeve.

Axle boxes for rail vehicles : Cylindrical roller bearings and double row self aligning spherical roller bearings with withdrawal sleeve.

h 9

-30

-36

-43

-52

-62

-74

-87

-100

-115

-130

-140

-155

h 10

Shaker and sifter shafts : Double row self aligning spherical ball bearings with adaptor sleeve.

Frame saw main shaft : Double row self aligning spherical roller bearings with adaptor

Line shafting : Double row self aligning ball bearings and self aligning barrel type roller bearings with adaptor sleeve.

Ship's propellor shafts, journal bearings : Cylindrical roller bearings with adaptor sleeve.

Rudder shafts : Double row self aligning spherical roller bearings with adaptor.

h 10

-48

-58

-70

-84

-100

-120

-140

-160

-185

-210

-230

-250

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lyobearing Participant Join Date: May 2012 Location: luoyang ,china Posts: 2	#4 Re: Operational Clearances for Bearings 05/31/2012 2:37 AM
	what is the rotation speed of the bearing ? Generally speaking , different speed use different radial clearance . clearance is not equal to tolerance . __________________ design precision bearing
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#3 "Re: Operational Clearances for Bearings" by isloorkar on 12/22/2009 9:12 AM (score 2)

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#1 "Re: Operational Clearences for bearings?" by Anonymous Poster on 12/17/2009 9:10 AM (score 1)

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Users who posted comments:

Anonymous Poster (1); Ed Weldon (1); isloorkar (1); lyobearing (1)

You might be interested in: Miniature Bearings and Instrument Bearings, Plain Bearings and Sleeve Bearings, Angular Contact Bearings

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