The spherical shape of the raceway in the outer ring enables the misalignment of the rings and ensures balanced distribution of load over the rolling elements even under the slightest shaft deflection, or even when the alignment of the bearing beds is not kept.
These unique parameters enable spherical bearings to:
• reach lower operating temperature and higher rotation speed,
• accommodate higher axial load,
• accommodate higher combined load,
• longer operating life.
At the same time certain mutual misalignment of the rings is allowed and so the bearings cope better with the real operating conditions and contribute to a better reliability and durability during the operating life of the bearings. Cylindrical Roller Bearings are suitable for arrangements, with high requirements for load transfer in connection with high rotation speed, e. g. machine tools, rolling mills, vehicle axle, etc.
The main dimensions of double row spherical roller bearings specified in the dimension tables are in accordance with the international standards ISO 15 (STN 02 4629).
Structure
The internal structure of the double row spherical roller bearings utilizes symmetric cylindrical rollers and in dependence on the cage design it has a number of modifications. The design with two-part pressed steel cage, with a floating central collar of the inner ring is marked “E…J” The bearing with a one-part brass cage running on the inner ring is marked “M” and two part brass cage is marked “MB”.
Tolerance
Double-row spherical roller and spherical roller thrust bearings are commonly produced in the basic P0 tolerance class. Production of bearings with a higher tolerance class should be discussed in advance with the manufacturer. The limit values of deviations in tolerances and the operation are specified in ISO 492.
Radial Clearance
Commonly produced double-row spherical roller bearings have normal radial clearance which is not indicated. In specific cases bearings with radial clearance C2 (smaller than normal clearance) or with the radial clearance C3, C4, C5 (greater than normal clearance) can be produced.
Lubrication Groove and Holes in the Outer Ring
In order to ensure better lubrication and higher reliability of the operation double-row spherical roller bearings have a groove and three lubrication holes (W33) in the outer ring.
Bore of the Inner Ring
Double row spherical roller bearings are produced with a cylindrical or a tapered bore (K), taper 1:12 or 1:30. Bearings with tapered bore are mounted directly to a tapered pivot or to a cylindrical pivot using adapter or withdrawal sleeves in accordance with ISO 2982-1,2.
Stabilisation for Operation at Higher Temperature
For arrangements with operating temperature higher than 120°C specially stabilised double row spherical roller bearings with stabilised shape for operating temperature from 150°C to 400°C (S0, S1, S2, S3, S4 and S5) that are in accordance with ISO 2982-1,2 are produced. Delivery of stabilised bearings should be discussed in advance with the manufacturer.
