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Timken - Saf Split-Block Housed Units

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<strong>Timken</strong> ® SAF SPLIT-BLOCK HOUSED UNITS<br />

Engineering • Bearing Types and Cages / Metric System Tolerances<br />

RADIAL SPHERICAL ROLLER BEARING TYPES and Cages<br />

The principle styles of radial spherical roller bearings that <strong>Timken</strong><br />

offers are:<br />

• ≤280 mm bore: EJ, EM and EMB<br />

• >280 mm bore: YM and YMB<br />

Above suffixes correspond to different types of designs depending<br />

on a bearing size and geometry. Main differences are the cage<br />

type used in the assembly. Spherical roller bearings with an EJ<br />

cage suffix are fitted with a stamped-steel cage. YM/EM/YMB<br />

suffixes are used with brass cage designs.<br />

The newly redesigned <strong>Timken</strong> ® EJ, EM and EMB bearings offer<br />

higher load ratings, increased thermal speed ratings and reduced<br />

operating temperatures compared to the previous offering.<br />

In addition to these improvements, cage designs vary between<br />

the different styles as noted below.<br />

Style<br />

EJ<br />

EM/YM<br />

EMB/YMB<br />

Cage Design<br />

land-riding steel cage; one per row<br />

Roller-riding one-piece brass cage<br />

Land-riding one-piece brass cage<br />

Most <strong>Timken</strong> ® spherical roller bearings are available with a<br />

cylindrical bore as well as a tapered bore. Tapered bore bearing<br />

part numbers are designated with a K suffix.<br />

Metric System Tolerances<br />

Spherical roller bearings are manufactured to a number of<br />

specifications, with each having classes that define tolerances<br />

on dimensions such as bore, O.D., width and runout. Metric<br />

bearings have been manufactured to corresponding standard<br />

negative tolerances.<br />

Boundary dimension tolerances for spherical roller bearing<br />

usage are listed in the following tables. These tolerances are<br />

provided for use in selecting bearings for general applications,<br />

in conjunction with the bearing mounting and fitting practices<br />

offered in later sections.<br />

The following table summarizes the different specifications and<br />

classes for spherical roller bearings and other available <strong>Timken</strong><br />

bearing lines. For the purposes of this catalog, ISO specifications<br />

are shown for spherical roller bearings.<br />

Table D-1. Bearing Specifications and classes<br />

System Specification Bearing Type Standard Bearing Class Precision Bearing Class<br />

Metric ISO/DIN All Bearing Types P0 P6 P5 P4 P2 –-<br />

Imperial ABMA Spherical RBEC 1 RBEC 3 RBEC 5 RBEC 7 RBEC 9 –-<br />

D-4 TIMKEN ® HOUSED UNIT CATALOG

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