137
ECB 22240 CCK JA / C3 W33
12
34
5
Spherical rollerbearings
6
W Without relubrication feature(W33) on E style bearings only
W4 High point of eccentricity markedon inner ring or sleeve
W22 Special reduced outside diameter tolerance for outer ring
W26 Six lubrication holes in inner ringW31 Bearing inspected to special
quality requirement
W33 Three oil holes and circumferentialgroove in outside diameter
W33X Lubrication groove and sixholes in outer ring
W502 Combination of W22 & W33W507 Combination of W4, W31 & W33W509 Combination of W26, W31 & W33HA1 Case hardened outer and
inner rings
HA3 Case hardened inner rings(equal to ECB)
VA405 Vibrating screen specificationVA751-VA759 Printing/coater roller specificationVT143 SKF grease LGEP2 supplied in
sealed spherical roller bearings
ECB Air melt carburized steel,inner ring only
BS2 Two row spherical rollerbearing, special dimensions
J Pressed steel cageJA Hardened steel cage, ring guidedM2 Machined brass roller guided cage,
no guide ring
MA Machine brass cage, ring guided2CS Sheet steel reinforced contact seal
of acrylonitrile butadiene rubber(NBR) on both sides of the bearing.Annular groove and three lubricationholes in the outer ring covered with a polymer band. Lubricated with amedium temperature grease.
2CS2 Sheet steel reinforced contact sealof fluoro rubber (FPM) on both sidesof the bearing. Annular groove and three lubrication holes in the outerring; covered with a polymer band.Lubricated with a high temperaturegrease.
2CS5 Sheet steel reinforced contact seal of hydrogenated acrylonitrile buta-diene (HNBR) on both sides of thebearing. Otherwise same as 2CS2.
F Machine steel cage, ring guidedY Pressed brass cage, ring guided
C1 Clearance < C2C2 Clearance < Normal(C0)* Normal clearanceC3 Clearance > NormalC4 Clearance > C3C08 RBEC 5 running accuracy,
inner and outer rings
1. Prefix: 4. Cage designs / seals: 6. Features:
5. Clearance / tolerance:
CA Integral side flanges,inner ring guided one-piece machined brass cage
CAC Same as CA designed sphericalroller bearing with improved rollerguidance
CAFA Bearing with symmetrical rollers,retaining flanges on the inner ring.Guide ring centered on the innerring, one-piece machined steelcage of the double pronged typecentered in the outer ring
CAMA As CAFA, but with a machinedbrass double pronged cage
CC Flangeless inners, symmetricalrollers, floating guide ring, pressedsteel cage
E Improved internal design,W33 feature is standard
2. Internal design:
Cylindrical boreK Bearing with 1 to 12
tapered bore
K30 Bearing with 1 to 30 tapered bore
3. Bore type:
*Not marked on bearing or package
Nom
enclature
138
Spherical roller bearings
* See width tolerances in SKF General Catalog (publication #6000 EN)
Product Details
Boundary dimensions In accordance with ISO 15-1998
Tolerances SKF spherical roller bearings are manufactured as Standard to Normal (RBEC 1, ISO P7) tolerances. SKF Explorer bearings up to 315 mm bore diameter are produced to higher precision than Normal tolerances. The width tolerance is considerably tighter*. The running accuracy is to tolerance class P5 as Standard.For larger bearings P5 tolerances are also available with the suffix C08 or closertolerances are available with suffix VQ424. Vibratory bearings are manufactured to bore P6 and O.D. P5.
Heat stabilization 392 F (200 C)
Misalignment Series 21300 - 1 degree Series 22200 - 1.5 degreesSeries 22300 - 2 degrees Series 23000 - 1.5 degreesSeries 23100 - 1.5 degrees Series 23200 - 2.5 degreesSeries 23900 - 1.5 degrees Series 24000 - 2 degreesSeries 24100 - 2.5 degrees
Cage materialStandard SteelOptional Machined brass (CA) larger bearings only
Axial load max For adapter mounts Fap = 3 x B x dwhere B = bearing width (mm)
Fap = axial load in NewtonsFor cylindrical mounts contact SKF
Seals 2CS 2 nitrile seals with med. temp. grease2CS2 2 vitron seals with high temp. grease2CS5 2 nitrile seals with high temp. grease
Technical features
Figure 1
139
Introduction Spherical roller bearings have two rows ofrollers with a common sphered raceway in theouter ring. The two inner ring raceways areinclined at an angle to the bearing axis. Thebearings are self-aligning and consequentlyinsensitive to errors of alignment of the shaftrelative to the housing, and to shaft bending. In addition to radial loads, the bearings can also accommodate axial loads acting in bothdirections.
SKF spherical roller bearings have a largenumber of long, symmetrical rollers of largediameter and consequently have very high loadcarrying capacity. Their internal design differsslightly depending on series and size, but hasbeen continually improved over the years. Thespecial form and optimized surface finish of theraceways provide that the bearings, especiallythose of the SKF Explorer, CC, CAC and Edesigns, have a minimum of friction. Thesebearings have lower operating temperatures orcan accommodate heavier axial loads, or can be operated at higher speeds than conventionalspherical roller bearings.
The E design constitutes the newer SKFstandard design for spherical roller bearings.There have been many developments andimprovements in design over the years andthey have been put together to produce an evenbetter bearingthe SKF Explorer. This repre-sents a new class of performance. Explorerbearings give more performance for the samesize: they can carry more load for longer, orthey can carry the same load as before evenmore reliably for much, much longer.
SKF spherical roller bearings are availablewith cylindrical bore and tapered bore. Thetapered bore of bearings in series 240 and 241have a taper of 1:30 (designation suffix K30)whereas the taper of all other bearings is 1:12(suffix K).
Introduction
Basic design SKF spherical roller bearings are made to oneof the designs described in the following para-graphs, depending on size and series.
CC and EC designs (Figure 1a)These bearings have symmetrical rollers, aflangeless inner ring and a pressed steel cagefor each roller row. The guide ring is centeredon the inner ring between the two rows ofrollers. EC design bearings incorporate rein-forced roller sets for increased load carryingcapacity. The surface finish of the rollers andraceways of bearings of the CC design has beenoptimized to promote roller guidance andreduce friction.
CAC, ECAC, CA and ECA designs(Figure 1b) These designs are used for the larger sizes ofSKF spherical roller bearings. The rollers aresymmetrical and the inner ring has retainingflanges. The guide ring is centered on the innerring between the two rows of rollers and thecage is a one-piece, double pronged machinedbrass cage. The CAC and ECAC designs incorporate the surface finish refinements ofthe CC design and the ECAC and ECA designshave reinforced roller complements forincreased load carrying capacity.
E design (Figure 1c) These bearings have symmetrical rollers, aflangeless inner ring and a sintered guide ringbetween the two rows of rollers, which is posi-tioned towards the outer ring and centered onthe two pressed steel window-type cages usedfor each row of rollers.
The E design bearings incorporate all theadvantages of the well-proven SKF CC bearingsas well as additional refinements. The pressedsteel cages have been newly developed andpermit the inclusion of a greater number and/orlarger diameter rollers of increased length,
imparting even higher load carrying capacity tothe bearings.
The positioning of the guide ring towards theouter ring enables lubrication at the roller endguide ring contact to be improved. The guidering contributes to the reduced friction in thebearing as it helps to guide the rollers in theunloaded zone and assists their entry into theloaded zone.
Self-aligning, robust designAllows misalignment between shaftand housing without increasing frictionor reducing bearing life. Also insensitiveto misalignment caused by shaft orhousing deflection due to heavy load.
Very high load carrying capacityOptimum internal design providesmaximum radial and axial load carryingcapacity.
Reduced friction and minimumheat generationSelf-guiding rolleran SKF patentmeans reduced friction and minimumheat generation.
Excellent performance at hightemperaturesHigh-strength, dimensionally stablebearing rings minimize the risk of ring breakage and also allow good performance at high temperatures.
Seals integrationUnder normal operating conditions,sealed SKF spherical roller bearings aregreased for life and make external sealsunnecessarysimplifying bearingarrangements and requiring minimummaintenance.
Special bearing series availablefor demanding applicationsHigh precision printing press bearingsand bearings for vibrating screenapplications.
Product highlights
Figure 2
140
Spherical roller bearings
Introduction
SKF Explorer class bearingsAvailabilityThe popular small and medium size sphericalroller bearings in the series 213, 222, 223,230, 231, 232 and a few sizes in the 239, 240and 241 are available as SKF Explorer bearings.The range is being extended in these bearingsseries as well as in other series.
In the product tables, the SKF Explorerbearing designations are printed in blue.
Product designationsThe SKF Explorer bearings retain the designa-tions of the earlier standard bearings, e.g.22218 E or 23032 CC/W33. However, eachbearing and its box is marked with the nameSKF Explorer so that there can be no confusion.
Additional details on Explorer perf
