skf sealed spherical roller bearings increase profits and...

SKF sealed spherical roller bearingsincrease profits and environmentalwelfare

Contents

Made by SKF® stands for excellence. It symbolises our consistent endeavour to achieve total quality in everything we do. For those who use our products, “Made by SKF” implies three main benefits.

Reliability – thanks to modern, efficient products, based on our worldwide application know-how, optim-ised materials, forward-looking designs and the most advanced production techniques.

Cost effectiveness – resulting from the favourable ratio between our product quality plus service facilities,and the purchase price of the product.

Market lead – which you can achieve by taking advantage of our products and services. Increased operating time and reduced down-time, as well as improved output and product quality are the key to a successful partnership.

1 Product information.................................................... 3

Economic and reliable .................................................... 3Why sealed spherical roller bearings from SKF? .......... 4A wide assortment range .............................................. 5Unique design features.................................................. 6

Where economy is desirable .......................................... 8

2 Recommendations.................................................... 10

Reduce costs with the SKF Trouble-Free Operation program .......................................................................... 10

Seal selection guidelines ............................................ 12Design of bearing arrangements ................................ 13Lubrication .................................................................. 14Maintenance ................................................................ 15Methods and tools to make things simpler ................ 16

3 Product data .............................................................. 19

Bearing data – general .................................................. 19Sealed spherical roller bearing designations .............. 21

Bearing tables ................................................................ 22Bearings d 40 – 100 mm ............................................ 22Bearings d 110 – 220 mm .......................................... 24

Other related products for optimum performance .... 26

The SKF Group – a worldwide corporation................ 30

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1Economic and reliable

Of particular and ever-increasingimportance is that sealed sphericalroller bearings are environmentallyfriendly and conserve resources.

Sealed spherical roller bearings areideal especially for bearing positionswhere, because of limited space or forcost reasons, sufficiently effectiveexternal seals cannot be provided.

Due to the integral seals and the in-corporated grease fill, they are able to:

● allow simpler as well as space-saving bearing arrangements, thussaving total costs;

● provide long service life and highreliability with minimal maintenancerequirements.

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Sealed spherical roller bearings arecharacterised by several valuableproperties. They are:

● sealed at both sides with rubbingseals which retain grease in thebearing;

● protected against contaminationand moisture;

● ready to mount and normally main-tenance-free;

● not susceptible to normal angularmisalignment and shaft alignmenterrors;

● capable of carrying heavy loads.

1 Product information 2 Recommendations 3 Product data

Customer benefits Page ............. 10 Page ............. 19

The use of SKF sealed sphericalroller bearings will provide the follow-ing benefits:

● Very high combined load carryingcapacityBoth radial and axial as the internalgeometry of the bearings corre-sponds to that of the open (unsea-led) bearings.

● Wide range of applicationTwo different seal variants and twodifferent greases can be supplied –for normal and for high operatingtemperatures.

● Long service lifeProven design, appropriate greasesand efficient sealing make this poss-ible.

● Minimum maintenance requirementsHighly efficient seals keep contam-inants and moisture out and the grease in.

● Better for the environmentThe bearings are normally mainten-ance-free. This reduces grease con-sumption and conserves resources– also for the user.

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Why sealed sphericalroller bearings fromSKF?Quite simply because of the expertisebehind the efficient seals.

In 1919, SKF invented the sphericalroller bearing. SKF has continued tofurther develop and refine the designincluding the way it is sealed. The bestproof of the total quality of SKF spher-ical roller bearings is their success.Twice as many SKF spherical rollerbearings are used today as those ofany other bearing manufacturer.

SKF spherical roller bearings arestate-of-the-art products. They are thesubject of a continuous improvementprocess designed to further enhanceperformance and reliability with theaim of conquering new and even moredemanding applications.

SKF is active worldwide to fulfil itsresponsibilities and as a consequence,many bearing arrangement problemscan be solved using SKF standardbearings, where otherwise expensivespecial bearings would have beenrequired.

The development of the sealedspherical roller bearing has followedthe SKF tradition. High demands onsealing efficiency and operational re-liability had to be fulfilled. The sealshave been extensively tested both inthe laboratory and in the field andhave proven their reliable performanceand efficiency.


Customer benefits Page ............. 10 Page ............. 19

Rugged

Tolerant to align-ment errors

Resistant to elev-ated temperatures

1The seals have been specially de-

veloped for the spherical roller bear-ings and effectively prevent contam-inants from penetrating to the rollingcontact area. This is not only true inoperation, but also during bearing in-stallation, resulting in long service life.

Two particularly suitable greaseshave been chosen for the bearings.One is an SKF grease recommendedfor normal operating temperatures.The other, a special high-temperaturegrease, is used in combination withfluoro rubber seals for high-temper-ature operation.

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A wide assortment rangeThe SKF range of sealed sphericalroller bearings comprises bearingswith cylindrical bore for shaft diametersof 40 to 220 mm from seven differentbearing series. Bearings with taperedbore can be produced to special order.

SKF sealed spherical roller bearings,depending on series and size, areproduced in the E or the CC design.The sealed bearings of the CC designgenerally have the same boundarydimensions as the correspondingopen bearings.


Product range Page ............. 10 Page ............. 19

Solid contaminantsexcluded

Moisture cannotenter

Always operatio-nally reliable

Unique design featuresThe design of SKF sealed sphericalroller bearings corresponds to that ofthe open (unsealed) standard bearings,and incorporates the same uniquedesign features. These include:

● symmetrical rollers with specialprofile;

● self-guiding rollers – an SKF patent;● floating guide ring between the two

rows of rollers;● bearing components dimensionally

stabilised for high temperatures and● window-type steel cages.

Additional features of the SKF sealedspherical roller bearings include:

● double-lip, sheet steel reinforcedseals and

● a grease appropriate to the oper-ating conditions.

The result is a ready-to-mount, lubric-ated-for-life bearing unit with a longservice life and which normally onlyrequires the same space as a standardopen bearing. The advantages includea simplification of the bearing arrange-ment design, and the option to down-size the arrangement. Equipment forrelubrication is not required, there isno waste grease in cooling watersystems, and there are no disposalcosts for used grease.

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Design features Page ............. 10 Page ............. 19

Very high loadcarrying capacityThe symmetricalrollers positionthemselves auto-matically so that theload is evenly dis-tributed over thewhole roller length.This results in veryhigh load carryingcapacity.

No edge stressesBecause of the spe-cial roller profilethere is virtually nodanger of edgestresses.

E designThe bearings havesymmetrical rollers,two window-typesteel cages centredon the inner ring, aflangeless inner ringand a floating guidering between thetwo roller rows.

CC designThe bearings havesymmetrical rollers,two window-typesteel cages, a flange-less inner ring and afloating guide ringbetween the tworoller rows. Theguide ring, which iscentred on the innerring, also guides thecages.

Low friction and low heatgenerationThe patented self-guidance of the rol-lers and the floatingguide ring, whichguides the rollersaxially through theunloaded zone,keep friction andheat generationdown.

Little risk of ringbreakageHigh-strength,dimensionally sta-bilised bearing ringsminimise the risk ofbreakage. They alsoallow the bearingsto perform welleven at very hightemperatures up to+180 °C (356 °F).

E design CC design

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Design features Page ............. 10 Page ............. 19

Light-weight, high-strength cagesThe window-typesteel cages are lightbut very stable andwear-resistant. Theytake up very littlespace so that anample supply ofgrease can be con-tained in the bear-ing.

Well protectedThe bearings have asheet steel reinforc-ed double-lip sealat each side. Theseals are made ofnitrile rubber orfluoro rubber. Thenitrile rubber sealsare for normal op-erating conditionsand can operate athigh speeds. Thefluoro rubber sealsare for high temper-atures and primarilyintended for lowspeed operation.

Well lubricatedBearings with nitrilerubber seals fornormal operatingtemperatures andreasonable speedsare lubricated withan SKF lithium basegrease with goodrust inhibiting prop-erties. The bearingsfor high temperatureuse have fluoro rub-ber seals and arelubricated with ahigh-temperaturepolyurea basegrease.

▲ ▲

Where economy is desirable

high contamination (water, dirt, scaleand coolant additives) – all factorswhich can be minimised when thecorrect bearings and seals are used.

Instead of tonnes of grease –freedom from maintenanceNormally a continuous casting plantrequires 10 to 100 tonnes of grease toprotect the bearings.

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Long service life, high reliability, min-imum maintenance and compactarrangement design have fuelled highdemand for SKF spherical roller bear-ings throughout industry. One primeexample is the steelmaking industry.The demands made on bearings whensteel is produced include extremelyheavy loads, high temperatures and

Applications

● Metallurgical● Mining & construction● Pulp & paper● Fluid machinery● Materials handling● Industrial gearboxes● Textile● Robotics● Railways

Requirements

● Long service life● High load carrying capacity● Insensitive to angular misalign-

ments and other errors ofalignment

● Minimum maintenance● Reduced operating costs● Improved environment

Solution

Sealed spherical roller bearingsenable a maintenance-free solution.The bearings are filled with a high-per-formance, high-temperature greasewhich does not have to be renewed.And, although the bearings have inte-gral rubbing seals, the bearings havethe same high load carrying capacityas their unsealed counterparts.


Many branches of industry Page ............. 10 Page ............. 19

The background photo is published by kind permission of British Steel –Sections, Plates & Commercial Steels.

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Many branches of industry Page ............. 10 Page ............. 19

Reduce costs with the SKFTrouble-Free Operation™ programme

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Page ............. 3 Trouble-free operation Page ............. 19

Today’s tough competition makes itcritical to utilise manufacturing plantsand machines to their fullest. Properbearing maintenance will help keepequipment running, but this requiresforesight, planning and the use of thebest available bearing accessories,mounting/dismounting methods andtools, and maintenance equipment.

SKF provides all the products andservices needed to achieve maximumequipment uptime, through the SKFTrouble-Free Operation programme.The benefits include reduced sparepart stores, minimised unplannedstops, and reduced repair downtime.

Single source for all bearings SKF mounting and dismounting tools

SKF service engineer on site

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Page ............. 3 Trouble-free operation Page ............. 19

The programme offers:

● high quality bearings and access-ories, whenever and wherever theyare needed;

● top-of-the-line mounting/dismount-ing tools, monitoring equipment,seals and lubricants;

● efficient and meaningfulmounting/dismounting and main-tenance training and

● advanced application engineeringservices locally and worldwide.

More information about the SKFTrouble-Free Operation programmeconcept will be supplied on requestfrom your local SKF sales office orsales representative.

Particles in the lubricantDirt in the bearing will damage both race-ways and rollers. The bearing will work, butscaling will soon start at one of the indenta-tions resulting in breakdown. Proper exter-nal seals, clean lubricant and a clean as-sembly process provide effective protectionfrom this type of bearing damage. However,the best and simplest method is to use SKF sealed spherical roller bearings.

Insufficient lubricant Inadequate lubrication will cause wear onthe surfaces subjected to load. Subsequentstress concentration around these areaswill result in scaling. Lubricant forms a filmwhich prevents direct contact between thesteel surfaces. If the film is too thin thecontacting surface peaks will weld togheterand then tear apart, leaving small pits in thesurfaces. Integral seals contribute to effici-ent lubrication by keeping the lubricant inposition inside the bearing.

Water in the lubricantWater penetrating because of inadequateexternal seals will cause deep corrosionand considerable wear. The bearing hasbeen standing still for some time, eviden-ced by the galvanic corrosion where therollers have been in contact with the bear-ing ring. Corrosion of this nature is danger-ous because it causes scaling and crackingof the bearing. This type of bearing damagecan be avoided by employing efficient sealsand correct anticorrosive lubricant.

Expert advice from the SKF applicationengineering service

Practical SKF seminars cover all there isto know about mounting and maintain-ing rolling bearings

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See also SKF catalogue 4006“CR seals”.

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Fluoro rubberFluoro rubber has very good thermaland chemical resistance and is alsoresistant to ageing and ozone attack.Seals of this material have exceptionalproperties. Even under extreme en-vironmental conditions they will withs-tand temperatures up to +200 °C (392°F) They are also resistant to oils andhydraulic fluids, fuels, mineral acidsand aliphatic and aromatic hydro-carbons which would cause nitrilerubber to fail.

Because of their special properties,fluoro rubber seals are available asstandard on most SKF sealed spher-ical roller bearings.

Warning: The chemical compositionof fluoro rubber is very stable andharmless under the above operatingconditions. However, if subjected toextreme temperatures there is a riskthat toxic vapours can be formed. Thissituation may occur for instance whena cutting torch is used to dismountand scrap bearings. Safety instruc-tions for how to act in these situationsare supplied by SKF on request.

Seal selection guidelinesSKF sealed spherical roller bearingsare available with seals of either

● nitrile rubber (NBR) or● fluoro rubber (FPM).

These materials have properties thatmake them particularly suited for spe-cific applications, which are describedin the following paragraphs.

Nitrile rubberNitrile rubber, or more properly acrylo-nitrile butadiene rubber, is virtually theuniversal material for all types of seal.The material is a co-polymer of acrylo-nitrile and butadiene and has, amongother properties, good resistance to

● many mineral oils and greases withmineral oil base,

● animal and vegetable oils andgreases, and to

● hot water.

The operating temperature range is −50 to +110 °C (−58 to +230 °F). Thematerial will harden at elevated tem-peratures.

Seal Grease Bearing Permissible operating conditionsmaterial design Rotational Temperature

(designation speed °Csuffix)

Nitrile rubber SKF normal Can be Speed rating up to +110(NBR) temperature relubricated in bearing table

grease (2CS with if bearing is polymer band relubricatedremoved)Cannot be 50 % of speed rating up to +70relubricated in bearing table(2CS withpolymer band)

Fluoro rubber High Can be Speed rating up to +180(FPM) temperature relubricated in bearing table

grease (2CS2 with if bearing ispolymer band relubricatedremoved)Cannot be Speed rating up to +180relubricated in bearing table(2CS2 withpolymer band)Cannot be Speed rating up to +180relubricated in bearing table(2CS2W – norelubricationfeature)

Selection of SKF sealed spherical roller bearings

Table


Page ............. 3 Seals Page ............. 00

Seals for spherical roller bearings

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1 2 3

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Design of bearingarrangementsFor the axial location of sealed spher-ical roller bearings on shaft ends, SKFnuts KM(L) with locking washers MB(L)are recommended. For bearingshaving a bore diameter larger than 200mm nuts of series HM 30 with lockingclip, series MS 30, are available.

When axially securing sealed spher-ical roller bearings in position, careshould be taken to see that no adja-cent component, e.g. shaft or housingshoulder, can foul the sealing lip. Whenusing a nut to locate the bearing, it isnecessary to insert an intermediatering between the bearing and the nut,and to extend the threaded portion ofthe shaft (➔ fig ).The outside dia-meter of this ring should not exceedthe maximum limits shown in thebearing table.

To make the dismounting of bear-ings with bore diameters of 80 mmand above easier, it is advisable to usethe SKF oil injection method, where oilunder high pressure is injected be-tween shaft seating and bearing. Thisconsiderably reduces the force re-quired to dismount the bearing, andalso practically eliminates any risk ofthe seating or bearing being damaged.

To use the oil injection method, it isnecessary to provide the requisiteducts and distributor grooves in theshaft (➔ fig ). Details of the recom-mended dimensions for the ducts,grooves and connecting threads will

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Seal selectionSeveral factors influence the choice ofseal type on SKF spherical roller bear-ings. The most important are

● the circumferential speed of thesealing lip;

● the thermal conditions, and● the chemical resistance or required

mechanical properties.

Depending on the application, one oranother of these factors will dominate.However, the price, availability and thegrease used must also be taken intoaccount. Table gives an overviewof the standard seals and the greasesused for SKF sealed spherical rollerbearings. It also indicates suitability ofthe bearings in respect of rotationalspeed and temperature conditions.

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See also SKF catalogue 4003“Large bearings”.

be found, for example, in the SKFcatalogue 4003 “Large bearings”.

As with other bearings with integralseals, SKF sealed spherical roller bear-ings should not be exposed to directjets of water. If there is a risk of freewater reaching the seals, it is advis-able to provide additional externalsealing for the bearing (➔ fig ).

Due to the efficient integral seals noadditional external seals are normallyrequired, which implies that compactbearing arrangements can be pro-duced in most cases. However, wherethe environmental conditions are verytough (heavy contamination, waterspray etc.) external seals should beemployed.

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Fig Fig Fig


Page ............. 3 Bearing arrangements Page ............. 19

An intermediate ring between bearingand locking washer (of the nut) protectsthe seal

Bearing seating with oil ducts andgrooves for easy dismounting

A sealed spherical roller bearing in anSNL plummer block housing

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LubricationSKF sealed spherical roller bearingsare supplied filled with high perform-ance grease and are ready to mount.There is a choice of two standardgreases: A normal temperature highquality SKF lithium base grease havinga mineral oil base, and a special high-temperature grease with a polyureabase. The most important technicaldata are given in Table .

RelubricationSKF sealed spherical roller bearingsare maintenance-free under normaloperating conditions. If they operateunder moderate loads and temperat-ures they can be considered as lubric-

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ated for life. When speeds and tem-peratures are high, relubrication canbe beneficial. When relubrication is tobe adopted, bearings incorporatingrelubrication features must be ordered.These bearings are identified by theabsence of suffix W in the bearingdesignation (➔ designation scheme on page 21).

Grease can be supplied via theannular groove and three lubricationholes in the outer ring. The bearingmust rotate during relubrication toachieve proper distribution of thegrease.

The lubrication holes in these bear-ings are covered as standard with apolymer band, which must be re-moved before mounting (➔ fig ). 4

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The same grease should beused for relubrication as thatoriginally supplied in the bear-ing. When relubricating, careshould be taken not to damagethe seals.

Technical data for grease used in SKFsealed spherical roller bearings


Page ............. 3 Lubrication Page ............. 19

Property SKF normal High temperaturetemperature grease grease

Consistency (NLGI Scale) 2 2 – 3

Soap base lithium polyurea

Colour light brown light beige

Base oil mineral ester

Operating temperaturerange, °C −20 to +110 −25 to +180

Dropping point toISO 2176, °C min. 180 min. 250

Kinematic viscosityof base oil at 40 °C, mm2/s 200 440

at 100 °C, mm2/s 16 38

Table

Fig Fig

Series BS2-22 bearing with polymerband

Retaining rings hold the seal in the outerring

876

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MaintenanceSKF sealed spherical roller bearingshaving a bore diameter of 110 mm andabove can be washed, inspected andregreased. The retaining rings shouldbe removed with care. The head of thetool used should have well roundededges (➔ fig ). Once the retainingrings have been removed, the innerring can be swivelled out and the sealsremoved via the rollers from thegrooves in the outer ring side faces.

When the seals are to be replacedthey should be inserted in the groovein the outer ring. While one hand isused to hold part of the seal in thegroove, the remainder should be pres-sed into the groove in sections, usinga thumb (➔ fig ). The seal shouldthen be fixed in position using theretaining ring. Compress the retainingring to insert it into the groove, thenre-expand it using a suitable toolotherwise the seals may be damaged.

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The appropriate quantity of greaseto be supplied to the bearing whenrelubricating can be obtained from

G = 0,0005 B D

whereG = grease quantity required for

relubrication, gB = bearing width, mmD = bearing outside diameter, mm

The seals of SKF sealed sphericalroller bearings having a bore diameterof 110 mm and above are secured byretaining rings inserted in the outerring (➔ fig ). The seals can thus beremoved from the bearing so that itcan be maintained, i.e. washed andregreased, after which the seals canbe reinserted and secured.

Bearing storageBefore leaving the factory, SKF sealedspherical roller bearings are treatedwith a corrosion inhibitor. They can bestored in their unopened original pack-ages for up to three years, providedthe relative humidity in the store doesnot exceed 60 % (➔ fig ).6

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Page ............. 3 Maintenance Page ............. 19

Fig Fig Fig

Correct storage of bearings and seals Removing a retaining ringInserting the retaining ring in the outerring

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See also SKF catalogue MP200“The Tools for Trouble-FreeOperation”.

bearing damage. Non-metallic compon-ents such as the seals remain cold, asdoes the heater itself.

Bearings with tapered boreTo effectively mount sealed sphericalroller bearings with tapered bore ontapered seatings it is only possible touse the drive-up distance as a meas-ure, and the “New SKF MountingProcedure” is recommended. This is based on measuring the axialdisplacement of the bearing on itstapered seating and allows an accur-ate determination of the initial startingposition.

The SKF catalogue MP200 “TheTools for Trouble-Free Operation” con-tains guideline values for the startingposition and axial displacement for allbearings with a bore diameter of 50mm and above.

Methods and tools tomake things simpler

MountingSkill and cleanliness are essentialwhen mounting bearings if they are toperform satisfactorily and attain theirfull potential. Above all, the correctmethod of mounting should be chosenand suitable tools used. This is par-ticularly important where sealed spher-ical roller bearings are concernedsince misalignments of the inner ringrelative to the outer ring in excess of0,5° may damage the seals.

Bearings with cylindrical boreSealed spherical roller bearings arenormally mounted with an interferencefit on the shaft and cannot simply bepressed into position. It is recommend-ed that the bearings be mounted when hot (➔ fig ). The temperaturedifferential between bearing and seat-ing depends on the degree of inter-ference and the bearing size. General-ly, bearings which are 60 to 80 °C (140 to 176 °F) hotter than the shaftcan be mounted with ease. Pleaseremember that the bearings shouldnever be heated to more than 110 °C(230 °F).

The use of an SKF induction heaterhas been found very advantageous (➔ fig ). An induction heater heatsthe bearing rapidly, and most modelsprovide a temperature control thatprevents overheating and consequent

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Page ............. 3 Mounting Page ............. 19

Fig Fig

Mounting a heated bearing Bearing on an SKF induction heater

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DismountingIf bearings, or other associated com-ponents, are to be re-used afterinspection, they must be dismountedas carefully as they were mounted. Forthis reason, it is wise when designingthe bearing arrangement, to makeprovisions for easy dismounting.

Recesses in the housing shoulder,or the use of a support ring betweenthe bearing and a shaft shoulderwhich the withdrawal tool can engage,are examples of such provisions.Small bearings can generally be re-moved using a mechanical puller.These withdrawal tools should gripover the rings from the inside or out-side and engage the side faces toprevent damage.

Dismounting large bearings with aninterference fit on the shaft is consid-erably easier if the SKF oil injectionmethod is used (➔ fig ). If thismethod is to be used, it is necessaryto make provisions at the bearing ar-rangement design stage for the neces-sary ducts and distributor grooves (➔ “Design of bearing arrangements”on page 12).

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See also SKF publication 4100 “SKF Bearing MaintenanceHandbook”.


Page ............. 3 Dismounting Page ............. 19

Fig Dismounting a bearing from a cylin-drical seating using the oil injectionmethod

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Condition monitoring of bearings in operationProperly dimensioned and mountedbearings are exceptionally reliablemechanical components as long as anadequate supply of suitable lubricantis available and other damagingevents or adverse operating condi-tions are avoided.

In spite of this, it is recommendedthat bearing condition be monitored incertain applications either periodicallyor continuously. Condition monitoringenables incipient bearing damage tobe detected and evaluated, so thatbearing replacement can be sched-uled for a time when the machine is notin operation, to avoid unplanned stop-pages. With careful planning it is poss-ible to exploit bearing service life com-pletely. It is recommended that bear-ing arrangements be routinely check-ed for noise (➔ fig ) and temperat-ure (➔ fig ) as well as visually, andthat the lubrication is also checkedregularly.

The most efficient way of monitoringbearing and/or machine condition isby vibration analysis (➔ fig ).14

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Page ............. 3 Condition monitoring Page ............. 19

Fig Fig

Noise testing Taking the temperature

Recording vibration measurements using an SKF Microlog data collection unit

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ating temperatures above +110 °C (230 °F), however, it is necessary touse bearings fitted with fluoro rubberseals, designation suffix 2CS2, andthe special high temperature grease.

Speed ratingsThe permissible speeds at whichsealed spherical roller bearings can be operated depends on the type ofseal and the type and quantity of thegrease used, the magnitude of theload and the ambient temperature,and they are considerably lower thanfor the corresponding open (unsealed)bearings. The speed ratings for bear-ings with nitrile rubber seals, lubric-ated with normal temperature grease,are approximately 40 % of those for

DimensionsThe boundary dimensions of SKFsealed spherical roller bearings are inaccordance with ISO 15-1981, exceptfor the width of bearings of seriesBS2-22. These are basically bearingsof series 222 E or 222 CC but aremade slightly wider in order for theseals to be integrated.

TolerancesSKF sealed spherical roller bearingsare produced to Normal tolerances asspecified in ISO 492:1994.

Internal clearanceSKF sealed spherical roller bearingsare produced as standard with Normalradial internal clearance to ISO5753:1991. To special order the bear-ings can be supplied with greaterradial internal clearance to C3 or C4specifications (➔ Table ). The valuesin the table apply to bearings beforemounting and under zero measuringload.

MisalignmentSKF sealed spherical roller bearingscan accommodate angular misalign-ments of the shaft with respect to thehousing of up to approximately 0,5°.This guideline value applies as long asloads are normal (C/P >10), and whenthe position of the misalignment isconstant with respect to the outer ring.Provided the guideline value is not ex-ceeded, there will be no detrimentaleffect on the efficiency of the seals.

Influence of operating temperatureon the bearing materialsAll SKF spherical roller bearings, includ-ing the sealed bearings, are subjectedto a special heat treatment so thatthey can be used at temperatures upto +200 °C (392 °F) for up to 2 500hours without any inadmissible dimen-sional changes occurring. For oper-

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Bearing data – general

Radial internal clearance of spherical roller bearings with cylindrical bore

open bearings. Bearings fitted withfluoro rubber seals and lubricatedwith the special high temperaturegrease are only intended for low speedoperation. The permissible speeds inthis case are determined by the quant-ity of grease incorporated.

Bore diameter Radial internal clearence d Normal C3 C4 over incl. min max min max min max

mm µm

40 50 35 55 55 75 75 10050 65 40 65 65 90 90 12065 80 50 80 80 110 110 145

80 100 60 100 100 135 135 180100 120 75 120 120 160 160 210120 140 95 145 145 190 190 240

140 160 110 170 170 220 220 280160 180 120 180 180 240 240 310180 200 130 200 200 260 260 340

200 225 140 220 220 290 290 380


Page ............. 3 Page ............. 10 Bearing data – general

Table

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Minimum loadTo guarantee satisfactory perform-ance, spherical roller bearings mustalways be subjected to a given min-imum load, especially if they are usedin applications with high accelerationsor rapid changes in the direction ofload. Under such conditions the inertiaforces of the rollers and cage and thefriction in the lubricant can have adetrimental influence on rolling condi-tions in the bearing and may causedamaging sliding movements to occurbetween the rollers and raceways.

The minimum load required forsealed spherical roller bearings in suchcases can be estimated using

Frm = 0,02 C – Y0Fa

whereFrm = minimum radial load, NC = basic dynamic load rating, NY0 = calculation factorFa = axial component of combined

load, N

The values of C and Y0 will be found inthe product table.

When starting up at low temperat-ures when the lubricant may be highlyviscous, even greater loads may berequired. The weights of the compon-ents supported by the bearing, to-gether with the external forces, oftenexceed the requisite minimum load. Ifthis is not the case, the bearing mustbe subjected to an additional radialload.

Equivalent dynamic bearing loadFor spherical roller bearings

P = Fr + Y1Fa when Fa /Fr ≤ eP = 0,67 Fr + Y2Fa when Fa /Fr > e

The values of e, Y1 and Y2 will befound in the bearing table.

Equivalent static bearing loadFor spherical roller bearings

P0 = Fr + Y0Fa

The values of Y0 will be found in thebearing table.


Page ............. 3 Page ............. 10 Bearing data – general

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shown opposite and the meaning ofthe individual figures and letters ex-plained in the order in which theyappear.

Sealed spherical rollerbearing designationsThe complete designation of a sealedspherical roller bearing consists of theseries and size identification and suf-fixes which identify the design, theseals, the grease and any other fea-tures. The designation scheme is

Designation scheme for SKF sealed spherical roller bearings

Designation examples: BS2-2215 C-2CS24030-2CS2W

Prefix– Bearing with standard dimensionsBS2 Bearing with non-standard width; special bearing

Bearing series22 Bearing of series 222 with increased width230 Bearing of series 230231 Bearing of series 231232 Bearing of series 232239 Bearing of series 239240 Bearing of series 240241 Bearing of series 241

Bore diameter08 × 5 40 mm bore diameterto44 × 5 220 mm bore diameter

Design– CC or E design – bearings with suffix 2CSW are CC design bearings while

bearings denoted with suffix 2CS are E design bearingsC CC design

Seals and grease2CS Sheet steel reinforced rubbing seal of nitrile rubber at both sides; normal

temperature grease; grease fill corresponds to 40 % of free space in bearing

2CS2 Sheet steel reinforced rubbing seal of fluoro rubber at both sides; high temperaturegrease; grease fill corresponds to 70 to 100 % of free space in bearing

Other features– Normal radial internal clearanceC3 Radial internal clearance greater than NormalC4 Radial internal clearance greater than C3W Without relubrication facility

BS2 C-2CS22 15-

2CS2240 30 W-


Page ............. 3 Page ............. 10 Designation scheme

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Principal Basic load ratings Fatigue Speed Mass Designationdimensions dynamic static load rating

limitd D B C C0 Pu

mm N N r/min kg –

40 80 28 89 700 98 000 10 600 2 200 0,57 BS2-2208-2CS80 28 89 700 98 000 10 600 280 0,57 BS2-2208-2CS2

45 85 28 77 100 88 000 9 500 2 000 0,62 BS2-2209 C-2CS85 28 77 100 88 000 9 500 260 0,62 BS2-2209 C-2CS2

50 90 28 84 500 100 000 11 000 1 900 0,67 BS2-2210 C-2CS90 28 84 500 100 000 11 000 240 0,67 BS2-2210 C-2CS2

55 100 31 115 000 137 000 15 000 1 700 1,00 BS2-2211-2CS100 31 115 000 137 000 15 000 200 1,00 BS2-2211-2CS2

60 110 34 140 000 173 000 19 000 1 600 1,30 BS2-2212-2CS110 34 140 000 173 000 19 000 190 1,30 BS2-2212-2CS2

65 120 38 148 000 183 000 21 200 1 500 1,60 BS2-2213 C-2CS120 38 148 000 183 000 21 200 180 1,60 BS2-2213 C-2CS2

70 125 38 179 000 228 000 25 500 1 400 1,80 BS2-2214-2CS125 38 179 000 228 000 25 500 170 1,80 BS2-2214-2CS2

75 115 40 152 000 232 000 28 500 950 1,55 24015-2CS115 40 152 000 232 000 28 500 130 1,55 24015-2CS2130 38 184 000 240 000 26 500 1 300 1,90 BS2-2215-2CS130 38 184 000 240 000 26 500 170 1,90 BS2-2215-2CS2

80 140 40 207 000 270 000 29 000 1 200 2,40 BS2-2216-2CS140 40 207 000 270 000 29 000 160 2,40 BS2-2216-2CS2

85 150 44 244 000 325 000 34 500 1 100 3,00 BS2-2217-2CS150 44 244 000 325 000 34 500 140 3,00 BS2-2217-2CS2

90 150 72 322 000 510 000 56 000 90 4,80 BS2-6359-2CS2160 48 282 000 375 000 39 000 1 000 3,70 BS2-2218-2CS160 48 282 000 375 000 39 000 130 3,70 BS2-2218-2CS2

100 150 50 248 000 415 000 45 500 800 3,20 24020-2CS150 50 248 000 415 000 45 500 95 3,20 24020-2CS2W

165 52 322 000 490 000 53 000 850 4,40 23120-2CS165 52 322 000 490 000 53 000 100 4,40 23120-2CS2W170 65 397 000 640 000 68 000 85 6,00 BS2-6169-2CS2

180 55 368 000 490 000 49 000 900 5,50 BS2-2220-2CS180 55 368 000 490 000 49 000 110 5,50 BS2-2220-2CS2180 60,3 414 000 600 000 63 000 700 6,70 23220-2CS180 60,3 414 000 600 000 63 000 85 6,70 23220-2CS2W

Serie BS2-22-2CS(2) Serie BS2-22 C-2CS(2) Design 2CS2W


Page ............. 3 Page ............. 10 Sealed spherical roller bearingsd 40 – 100 mm

The speed rating for bearings of the2CS design is valid only when thebearing is relubricated (➔ Table 1,page 12).

3

23

Dimensions Abutment and fillet dimensions Calculation factors

d d2 D1 r1,2 b K da da Da ra e Y1 Y2 Y0≈ ≈ min min max max max

mm mm –

40 47 73 1,1 5,5 3 47 47 73 1 0,28 2,4 3,6 2,547 73 1,1 5,5 3 47 47 73 1 0,28 2,4 3,6 2,5

45 53 77,1 1,1 5,5 3 52 53 78 1 0,26 2,6 3,9 2,553 77,1 1,1 5,5 3 52 53 78 1 0,26 2,6 3,9 2,5

50 58,1 82,1 1,1 5,5 3 57 58 83 1 0,24 2,8 4,2 2,858,1 82,1 1,1 5,5 3 57 58 83 1 0,24 2,8 4,2 2,8

55 64 91,9 1,5 5,5 3 64 64 92 1,5 0,24 2,8 4,2 2,864 91,9 1,5 5,5 3 64 64 92 1,5 0,24 2,8 4,2 2,8

60 69,3 100 1,5 5,5 3 69 69,3 101 1,5 0,24 2,8 4,2 2,869,3 100 1,5 5,5 3 69 69,3 101 1,5 0,24 2,8 4,2 2,8

65 74 111 1,5 5,5 3 74 74 111 1,5 0,24 2,8 4,2 2,874 111 1,5 5,5 3 74 74 111 1,5 0,24 2,8 4,2 2,8

70 80,1 115 1,5 5,5 3 79 79 116 1,5 0,23 2,9 4,4 2,880,1 115 1,5 5,5 3 79 79 116 1,5 0,23 2,9 4,4 2,8

75 81,8 105 1,1 5,5 3 81,8 81,8 108 1 0,28 2,4 3,6 2,581,8 105 1,1 5,5 3 81,8 81,8 108 1 0,28 2,4 3,6 2,584,5 119 1,5 5,5 3 84 84,5 121 1,5 0,22 3 4,6 2,884,5 119 1,5 5,5 3 84 84,5 121 1,5 0,22 3 4,6 2,8

80 92,0 128 2 5,5 3 90 92 130 2 0,22 3 4,6 2,892,0 128 2 5,5 3 90 92 130 2 0,22 3 4,6 2,8

85 98,2 138 2 5,5 3 95 98 140 2 0,22 3 4,6 2,898,2 138 2 5,5 3 95 98 140 2 0,22 3 4,6 2,8

90 100 131 1,1 5,5 3 97 100 143 1 0,40 1,7 2,5 1,6103 148 2 5,5 3 100 103 150 2 0,24 2,8 4,2 2,8103 148 2 5,5 3 100 103 150 2 0,24 2,8 4,2 2,8

100 108 139 1,5 5,5 3 108 108 141 1,5 0,28 2,4 3,6 2,5108 139 1,5 – – 108 108 141 1,5 0,28 2,4 3,6 2,5

113 152 2 5,5 3 110 113 155 2 0,27 2,5 3,7 2,5113 152 2 – – 110 113 155 2 0,27 2,5 3,7 2,5110 150 2 5,5 3 110 110 160 2 0,37 1,8 2,7 1,8

114 160 2,1 8,3 4,5 112 114 168 2 0,24 2,8 4,2 2,8114 160 2,1 8,3 4,5 112 114 168 2 0,24 2,8 4,2 2,8114 160 2,1 8,3 4,5 112 114 168 2 0,30 2,3 3,4 2,2114 160 2,1 – – 112 114 168 2 0,30 2,3 3,4 2,2


Page ............. 3 Page ............. 10

24

Principal Basic load ratings Fatigue Speed Mass Designationdimensions dynamic static load rating

limitd D B C C0 Pu

mm N N r/min kg –

110 170 45 267 000 440 000 46 500 900 3,75 23022-2CS170 45 267 000 440 000 46 500 110 3,75 23022-2CS2W180 56 374 000 585 000 61 000 800 5,55 23122-2CS180 56 374 000 585 000 61 000 95 5,55 23122-2CS2W180 69 460 000 750 000 78 000 630 6,85 24122-2CS180 69 460 000 750 000 78 000 80 6,85 24122-2CS2W

120 180 46 305 000 510 000 53 000 850 4,20 23024-2CS180 46 305 000 510 000 53 000 100 4,20 23024-2CS2W180 60 374 000 670 000 68 000 670 5,40 24024-2CS180 60 374 000 670 000 68 000 80 5,40 24024-2CS2W200 80 575 000 950 000 95 000 560 10,0 24124-2CS200 80 575 000 950 000 95 000 70 10,0 24124-2CS2W

130 200 52 374 000 610 000 61 000 800 6,10 23026-2CS200 52 374 000 610 000 61 000 95 6,10 23026-2CS2W200 69 477 000 830 000 81 500 600 7,95 24026-2CS200 69 477 000 830 000 81 500 75 7,95 24026-2CS2W210 80 598 000 1 000 000 100 000 530 11,0 24126-2CS210 80 598 000 1 000 000 100 000 67 11,0 24126-2CS2W

140 210 69 495 000 900 000 88 000 560 8,45 24028-2CS210 69 495 000 900 000 88 000 70 8,45 24028-2CS2W225 85 673 000 1 160 000 112 000 500 13,0 24128-2CS225 85 673 000 1 160 000 112 000 60 13,0 24128-2CS2W

150 225 75 564 000 1 040 000 100 000 530 10,5 24030-2CS225 75 564 000 1 040 000 100 000 67 10,5 24030-2CS2W250 100 897 000 1 530 000 146 000 450 19,5 24130-2CS250 100 897 000 1 530 000 146 000 56 19,5 24130-2CS2W

160 240 80 656 000 1 200 000 114 000 500 13,0 24032-2CS240 80 656 000 1 200 000 114 000 60 13,0 24032-2CS2W270 86 845 000 1 400 000 129 000 530 20,5 23132-2CS270 86 845 000 1 400 000 129 000 67 20,5 23132-2CS2W

170 280 109 1 070 000 1 860 000 170 000 400 26,5 24134-2CS280 109 1 070 000 1 860 000 170 000 50 26,5 24134-2CS2W

180 280 100 937 000 1 730 000 156 000 430 23,0 24036-2CS280 100 937 000 1 730 000 156 000 55 23,0 24036-2CS2W

190 320 128 1 400 000 2 500 000 212 000 340 42,0 24138-2CS320 128 1 400 000 2 500 000 212 000 50 42,0 24138-2CS2W

200 340 140 1 580 000 2 800 000 232 000 320 52,0 24140-2CS340 140 1 580 000 2 800 000 232 000 50 52,0 24140-2CS2W360 128 1 610 000 2 700 000 228 000 340 58,0 23240-2CS360 128 1 610 000 2 700 000 228 000 50 58,0 23240-2CS2W

220 300 60 546 000 1 080 000 93 000 600 13,0 23944-2CS

Design 2CS Design 2CS2W


Page ............. 3 Page ............. 10 Sealed spherical roller bearingsd 110 – 220 mm

The speed rating for bearings of the2CS design is valid only when thebearing is relubricated (➔ Table 1,page 12).

3

25

Dimensions Abutment and fillet dimensions Calculation factors

d d2 D1 r1,2 b K da da Da ra e Y1 Y2 Y0≈ ≈ min min max max max

mm mm –

110 122 157 2 8,3 4,5 120 122 160 2 0,22 3 4,6 2,8122 157 2 – – 120 122 160 2 0,22 3 4,6 2,8123 166 2 8,3 4,5 120 123 170 2 0,27 2,5 3,7 2,5123 166 2 – – 120 123 170 2 0,27 2,5 3,7 2,5121 163 2 5,5 3 120 121 170 2 0,35 1,9 2,9 1,8121 163 2 – – 120 121 170 2 0,35 1,9 2,9 1,8

120 133 168 2 5,5 3 130 133 170 2 0,20 3,4 5 3,2133 168 2 – – 130 133 170 2 0,20 3,4 5 3,2130 166 2 5,5 3 130 130 170 2 0,28 2,4 3,6 2,5130 166 2 – – 130 130 170 2 0,28 2,4 3,6 2,5132 179 2 5,5 3 130 132 190 2 0,37 1,8 2,7 1,8132 179 2 – – 130 132 190 2 0,37 1,8 2,7 1,8

130 145 186 2 8,3 4,5 140 145 190 2 0,21 3,2 4,8 3,2145 186 2 – – 140 145 190 2 0,21 3,2 4,8 3,2141 183 2 5,5 3 140 141 190 2 0,30 2,3 3,4 2,2141 183 2 – – 140 141 190 2 0,30 2,3 3,4 2,2142 190 2 5,5 3 140 142 200 2 0,33 2,0 3,0 2,0142 190 2 – – 140 142 200 2 0,33 2,0 3,0 2,0

140 152 194 2 5,5 3 150 152 200 2 0,28 2,4 3,6 2,5152 194 2 – – 150 152 200 2 0,28 2,4 3,6 2,5153 203 2,1 8,3 4,5 152 153 213 2 0,35 1,9 2,9 1,8153 203 2,1 – – 152 153 213 2 0,35 1,9 2,9 1,8

150 162 206 2,1 5,5 3 162 162 213 2 0,28 2,4 3,6 2,5162 206 2,1 – – 162 162 213 2 0,28 2,4 3,6 2,5163 221 2,1 8,3 4,5 162 163 238 2 0,37 1,8 2,7 1,8163 221 2,1 – – 162 163 238 2 0,37 1,8 2,7 1,8

160 173 218 2,1 8,3 4,5 172 173 228 2 0,28 2,4 3,6 2,5173 218 2,1 – – 172 173 228 2 0,28 2,4 3,6 2,5180 244 2,1 13,9 7,5 172 180 258 2 0,28 2,4 3,6 2,5180 244 2,1 – – 172 180 258 2 0,28 2,4 3,6 2,5

170 185 249 2,1 8,3 4,5 182 185 268 2 0,37 1,8 2,7 1,8185 249 2,1 – – 182 185 268 2 0,37 1,8 2,7 1,8

180 195 251 2,1 8,3 4,5 192 195 268 2 0,31 2,2 3,3 2,2195 251 2,1 – – 192 195 268 2 0,31 2,2 3,3 2,2

190 210 284 3 11,1 6 204 210 306 2,5 0,4 1,7 2,5 1,6210 284 3 – – 204 210 306 2,5 0,4 1,7 2,5 1,6

200 220 300 3 11,1 6 214 220 326 2,5 0,4 1,7 2,5 1,6220 300 3 – – 214 220 326 2,5 0,4 1,7 2,5 1,6227 318 4 16,7 9 218 225 342 3 0,35 1,9 2,9 1,8227 318 4 – – 218 225 342 3 0,35 1,9 2,9 1,8

220 239 284 2,1 8,3 4,5 232 239 288 2 0,15 4,5 6,7 4,5


Page ............. 3 Page ............. 10

26

Other related products for optimum performance

See also SKF publication 4401“SKF spherical roller bearings – profit from our leadership”.

Spherical roller bearingsSelf-aligning bearings are the SKF flag-ship. The spherical roller bearing wasinvented at SKF by Arvid Palmgren in1919. Since then it has undergonethree major development stages. Thefirst of these culminated in the C de-sign which had markedly improvedperformance. The second brought theCC design with lower friction and high-er speed capability. The third andmost recent produced the E designwith optimised load carrying capacity.

The SKF range of spherical rollerbearings covers all the 12 dimensionseries found on the market today and

sizes range from 20 to 2 300 mm borediameter. This is the most comprehens-ive range available from any sourcetoday. All sizes can be supplied witheither a cylindrical or a tapered boreenabling various methods of shaftmounting to be used.

For specific demands several spe-cial bearings are available, e.g. bear-ings for vibrating machines or for cold Pilger mills.

27

Lock nutsSKF lock nuts, also referred to as shaftnuts, are available in several designsto axially locate bearings on shaftends. The most popular are those ofseries KM, KML and HM. These nutshave four or eight equally spaced slotsin the outside diameter and are lockedin position with locking washers orlocking clips engaging a groove in theshaft. The nut dimensions are inaccordance with ISO 2982-2:1995 as

See also SKF catalogue 3766/I“Bearing accessories”.

are the dimensions of the series MBand MBL locking washers.

Other lock nuts produced by SKFinclude those of series KMT, KMK andKMF which do not require a specialgroove in the shaft.

28

Lubricating greasesLubrication is an integral part of rollingbearing technology. For SKF, therefore,lubricating greases are bearing designcomponents. For this reason, SKF has13 lubricating greases for rolling bear-ings, each suitable for different applica-tion areas.

See also SKF catalogue MP200“The Tools for Trouble-FreeOperation”.

Tools and methods for mounting anddismountingSKF sealed spherical roller bearingsrequire a high degree of skill whenmounting or dismounting them as wellas the correct tools and methods.

The comprehensive SKF range oftools and equipment includes all thatis required, e.g. various sizes of induc-tion heater and several designs ofhydraulic equipment.

SKF lubricating greases and grease gun

Induction heater,hydraulic pumps,hydraulic nut,mounting fluid andanti-fretting pastefrom SKF

30

The SKF Group– a worldwide corporation

SKF is an international industrial Groupoperating in some 130 countries and isworld leader in bearings.

The company was founded in 1907following the invention of the self-align-ing ball bearing by Sven Wingquist and,after only a few years, SKF began toexpand all over the world.

Today, SKF has some 43 000 em-ployees and around 80 manufacturingfacilities spread throughout the world.An international sales network includesa large number of sales companies andsome 20 000 distributors and retailers.Worldwide availability of SKF productsis supported by a comprehensive technical advisory service.

The key to success has been a con-sistent emphasis on maintaining thehighest quality of its products and services. Continuous invest-ment in research and

development has also played a vitalrole, resulting in many examples ofepoch-making innovations.

The business of the Group consistsof bearings, seals, special steel and acomprehensive range of other high-tech industrial components. The experi-ence gained in these various fieldsprovides SKF with the essential know-ledge and expertise required in orderto provide the customers with the mostadvanced engineering products andefficient service.

31

The SKF house colours are blue and red,but the thinking is green. The latest exampleis the factory in Malaysia, where the bearingcomponent cleaning process conforms tothe strictest ecological standards. Instead of trichloroethylene, a water-based cleaningfluid is used in a closed system. The clean-ing fluid is recycled in the factory's own treatment plant.

The SKF Engineering & Research Centre is situated just outside Utrecht in TheNetherlands. In an area of 17 000 squaremetres (185 000 sq.ft) some 150 scientists,engineers and support staff are engaged inthe further improvement of bearing perform-ance. They are developing technologiesaimed at achieving better materials, betterdesigns, better lubricants and better seals – together leading to an even better under-standing of the operation of a bearing in itsapplication. This is also where the SKF LifeTheory was evolved, enabling the design of bearings which are even more compact and offer even longer operational life.

SKF has developed the Channel concept infactories all over the world. This drasticallyreduces the lead time from raw material toend product as well as work in progressand finished goods in stock. The conceptenables faster and smoother informationflow, eliminates bottlenecks and bypassesunnecessary steps in production. TheChannel team members have the know-ledge and commitment needed to share theresponsibility for fulfilling objectives in areassuch as quality, delivery time, productionflow etc.

SKF manufactures ball bearings, roller bearings and plain bearings. The smallestare just a few millimetres (a fraction of aninch) in diameter, the largest several metres.In order to protect the bearings effectivelyagainst the ingress of contamination andthe escape of lubricant, SKF also manu-factures oil and bearing seals. SKF's subsidiaries CR and RFT S.p.A. are amongthe world's largest producers of seals.

© Copyright SKF 1998The contents of this publication are thecopyright of the publisher and may notbe reproduced (even extracts) unlesspermission is granted. Every care hasbeen taken to ensure the accuracy ofthe information contained in this publica-tion but no liability can be accepted for any loss or damage whether direct,indirect or consequential arising out ofthe use of the information containedherein.

Publication 4404 E

Printed in Sweden on environmentallyfriendly, chlorine-free paper (MultiartSilk) by Halls Offset AB.

skf sealed spherical roller bearings increase profits and...

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