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and )bearingFluid film bearing(Journal Comparison between :roller bearing

Roller bearing Journal bearing comparison

operate efficiently in low speed

operate efficiently in high speed Speed

lower friction in lower speed but higher friction in high speed

Friction

relatively less reliable more reliable Reliability

doesn't need maintenance need maintenance Maintenance

we must replace it if failure occurred

Possible re-repair Repairing

relatively lower rpm precision

higher rpm precision Accuracy

less rigid more rigid Rigidity

Doesn’t withstand the shocks and high loads

Bear the shocks and high loads Shocks

relatively less length very long to bear the shocks and high loads

Axial length(width)

used in lower speed application like gear box

used in higher speed application like turbines and compressors….etc

Application

expensive Relatively inexpensive Cost

Short life Long life Bearing Life

Higher possibility to failure occur

Lower possibility to failure occur failure

Ball bearing, Cylindrical roller bearing, Taper roller bearing and Needle bearing.

Journal bearing(sleeve bearing) Examples

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Jmetal و power loss HIDوfriction @ABCDه6Bearing @ABCD Eف ا<9=9> ;: ا6789ام 4ا2 -1to metal contact @ABCDوwear .

2- KABL=Mroller bearing 6وثO2 failure <2ا PQRS82 T2ة وذRAWآ dust and fatigue

.اوآT2a اذا ;H` ;: اEZ [B8\ P]=Z ^\_2ر 3- `Hc\ =d\6ejournal bearing @d; KHAS; ادE; :; ص=iR2س وا=OH2ا ak] ذا=Z lubrication =Zك @mS\و R4cHD دة=m2ا naن ه lubricated.<Z=آ RAp نEq\ PHq2و. 4- roller bearing سR82ا Rms <Bs tZ=O\ P]u T2وس وذR826وق اHi <Z `QEB2 Jw]ن اEq\

<Bs ىE8O\ > P]ا =mآ Rdاآ large clearance yqs <Bs journal bearing ىE8O\ ىa2ا <Bslarge clearance 6مs <2دى اzAZ =4{SL `; 6A| @q}L وسR82ا ~A}SD.

5- K2=e <Z wind mill 678مw\cylindrical roller bearing @mO8\ P]u T2وذradial load

KA2=s ز\=دة JWwL T2وذcontact surface 678مw\ ={\واaxial thrust bearing @mO8\ <qDaxial load 678مw\ >و journal bearing نu T2وذ wind mill K{k7H; KsRwL 6ورD.

6-ms ك=Hاذا آ=ن هE @q� <Bs دsimply supported 6ىHs وآ=ن axial load ان JIAZ

<Bs @mO2ا اaه @A}]bearing �CZ 6eوا JHI82thermal stresses

. 7- deep groove ball bearing Angular @A}AL axial load نEq\ �CZ 6eوا n=IDا <Z

two angular deep groove ball bearing �AOL وBs{=ن \{A@ اZ @mO2> اID=ه678w] :Aم Eq\ اE]و :Aw;�8;�SL yqs .

8- self alignment ball bearing نEqAL outer race @q� <Bs spherical P]ا PD6�=Zو

@mO8\ 6رC\ high slope @BCAL P]ا JAs :q2د وEmS2ا <Z @cO\ :qm; <B2اload capacity n=IDا <Zaxial 6ثO\ ن=mوآ metal to metal contact.

9- Thrust bearing n=IDا <Z ل=me>ا naة و هRAWل آ=meu ضRS8\ axial �CZ.

10- Cylindrical roller bearing n=IDا <Z KA2=s ل=meا @A}\ radial �CZ. Zfriction :AL> اsRw2=ت اKA2=S2 وذ6e JWw\ P]u T2وث 678w\ >ball bearingم -11

balls &separator <mO\ ىa2اballs 824=;: ا{SL `; y;�.

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12-journal bearing yqs ةRAWq2ل ا=me>6;=ت واc2ا @mO8\ ان `A�8w\roller bearing

T2ن وذ>oil film thickness <Zjournal bearing @mSD ن=m6;=ت وآc2ا :; @BCDdamping :; @BC8Znoise ان =mآrigidity yqs <Bs K8L=� roller bearing نEq8Z

rigidity ة ;` دورانRA�8;rollers JWwAZ ^L=� RAp @mO2ن اEqAZnoise 6ا| KA2=s.

13- KA68ا�L>ا KkBq82ا roller bearing K268S; KkBq82ن اEqD =4H; RAW6د آs ^\R8او ا� :q2و KSkDR;.

@ 6Hs ا6789ا;Z P> اCAW�82=ت اq}L @mSD <82@ دا�� ;Djournal bearing d_داد آk=ءة -14turbines @ms 6Hs PDء=kآ =CDوon & off ارRm89=L.

15- K2=e <Zjournal bearing 678مw] :qm;needle bearing `QED �Aeneedle 6لL

oil :ALjournal & sleeve ود_] :qm; T2aLوload n=ID>ا <Z.

16- rating life( life of bearing) ^W| E2 �d; bearing100 �4Dاص ودورE72ا yk] �42 parallel RwqH\ <8e �m\ ىa2ا ^ME2=Z10 bearings <mw\rating life (L10).

وآZ `; T2a> اCAW�82=ت ا678w\ grease <Zlubrication K{k7H; KsRwL @mSD <82م -17

K{k7Hm2ارة اRO2در|=ت ا)up to 90ºc ( `; yqS2ا <Bs oil .

.واBs Kmmc;oil �AOi yqS2> ا6789ام bearingو greaseام < \�Bc ا18-6789

19- `Qو @{k\seal <Bsbearing ا6789ام K2=e <Zgrease @ms <Zlubrication >و . K2=e <Z `QE\oil ا6789ام

20- predictive maintenance ا|_اء <Z 6ثOD <82ل ا=�s>678م <آ8{=ف اw\bearing

<Z اذا آ=نouter race or inner race @q� <2ا R�H2ا ~\R� :s T2وذspectrum KZRS;و .وq; 6\6OD=ن اpeaks �W{2=L @�S2ا;=آ:

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