Spherical Roller Bearings: uses, dimensions, advantages

Spherical Roller Bearings

Spherical Roller Bearings are designed for carrying high loads. Of all rolling bearings spherical roller bearings are applied wherever high shock forces are present. In addition to shock loading this type of bearing is capable of handling various  misalignment and shaft deflections.

Spherical Roller Bearings are of a double row design, with two rows of rollers sharing a common spherical raceway in the outer ring. This feature enables this bearing to be completely self aligning. The wide series version of Spherical roller bearings has an integral flange which guides the roller and is utilized between the raceways of the inner ring. When in no load the rollers maintain line contact with the raceways of the inner ring and point contact at an extremely high degree of osculation with the raceway in the outer ring.

The rollers are barrel shaped with one end larger than the other. As a result of this design the rollers are pushed against the center guide flange with a  force which  while small is great enough to hold the larger end surface of the rollers in continuous contact with the flange ensuring proper guidance. With both the guiding surface of the flange and the end surfaces being  spherical, full surface contact is maintained. The real purpose of the flanges is keeping the rollers in the bearing when the outer ring is removed.

Machine brass cages with open pockets are commonly used in this type of bearing. This type of cage design allows for lubricants to reach the rolling and sliding surfaces from both sides easily. As a rule the outer ring likely has a peripheral groove with three radial holes in the outer ring which allows for feeding lubricant to the bearing efficiently.

Bearing rings and rolling elements are generally manufactured using AISI 52100 chromium steel. While brass cages are the most common for roller retention other materials used include Sheet steel, Polymide and machined steel.

All sizes and types of spherical roller bearings are made with tapered bores where they can be mounted using and adapter, a removable sleeve or directly mounted on a mating tapered shaft.

Narrow Spherical  roller bearings

In the narrow type of spherical roller bearing no integral flanges are used in the design. The rolling guidance is accomplished by a separate guide inserted into the outer ring by elastic deformation. The narrow spherical roller bearing is very useful for high radial capacity applications. The reduced width and reduced angularity of the rollers causes this type of bearing to have a lesser axial capacity than the wide type. Sometimes the narrow version is substituted for a ball bearing where they would have insufficient load carrying capacity and where then narrow width could be used. This type of bearing can also be manufactured in small sizes.

The most common series are 213, 222, 223, 231, 232, 238 and 239.

Applications for Spherical roller bearings include vibrating screens, rolling mills, shakers, conveyors, transmissions, heavy support rollers , stone crushers, Wind turbines, all types of mining and construction equipment and material handling equipment.