Tapered roller bearings are designed so that the imagined conical apices formed by the raceways of the inner and outer rings and the rollers all converge at one point on the bearing axis. The trapezoidal tapered rollers used as the rolling elements are guided by a large rib on the inner ring. TRBs can take radial loads and axial loads in one direction. When load is applied, the axial component generated inside the bearing generally requires the use of two opposed bearings (similar to angular contact ball bearings) or double-row bearings. Spacers are used to adjust the inner and outer rings in the axial direction to achieve the proper internal clearance. Since they are separable, the inner ring (cone) assemblies and outer rings (cups) can be mounted independently. The HR Series increases both the size and number of rollers for even higher load capacity. Tapered roller bearings are divided by their contact angle into normal-, medium-, and steep-angle types. In addition to double-row types, four-row tapered roller bearings are also available. Pressed cages are generally used, though large bearings may utilize pin-type cages. Metric series medium- and steep-angle tapered roller bearings use contact angle code “C” or “D” respectively after the bore number, while no code is used with normal-angle bearings. Medium-angle tapered roller bearings are primarily used for the pinion shafts of differential gears in automobiles. Bearings in the high-load capacity HR Series with “J” after the basic designation conform to ISO specifications for outer ring width, outer ring raceway small end diameter, and contact angle. This makes the inner ring (cone) assemblies and outer rings (cups) of bearings with the same basic designation internationally interchangeable. Some metric-design tapered roller bearings specified by ISO 355 have new dimensions different than those used in previous 3XX dimension series. For more information, please see the catalog bearing tables. Bearing designations are structured as follows (note that past Metric Series have a different nomenclature): Tapered roller bearings also come in Inch Series specifications. The designations of inner ring assemblies and outer rings of inch-design bearings (excluding four-row tapered roller bearings) are formulated differently: In tapered roller bearings, the outer ring is sometimes referred to as the “cup” and the inner ring assembly as the ”cone". These are sometimes called “sub-units”, with a single bearing referred to as a “unit”. Bearing designations are formed with the code for the inner ring assembly first, followed by the code for the outer ring. Download NSK Rolling Bearing Catalog